Abstract WILLIAMS, STEPHANNIA. Hydroentanglement Process as a Finishing Treatment for

the Enhancement of Knitted Fabrics. (Under the direction of Dr. Behnam Pourdeyhimi,

Dr. William Oxenham, and Dr. Tim Clapp.)

This research involves the application of hydroentangling technology as a means of

significantly improving knitted fabric properties. Hydroentanglement describes a

versatile process for manufacturing fabrics using fine, closely spaced, high velocity jets

of water to entangle loose arrays of fibers. Hydroentanglement is a stable, relatively

mature technology that sees mass use in the nonwovens industry.

In the past, various efforts have been made, directed at improving the dimensional

stability and physical properties of woven and knitted fabrics through the finishing

technique of hydroentanglement. In such applications, warp and filling fibers in fabrics

are hydroentangled at crossover points to effect enhancement in fabric cover. Several

U.S. patents describe these efforts, but there remains a need to better reduce the pilling

tendency and better improve abrasion resistance of a pillable fabric utilizing a physical

finishing method that can be employed based upon specific process parameters for

generation of an antipilling fabric.

The process parameters of hydroentangling are investigated and optimized to achieve

desired results. Fabric selection was based on industry interest and includes ring spun

single knit and double knit constructions in fiber combinations of cotton, polyester, and

cotton/polyester blended fibers. Potential benefits include enhanced fabric durability,

stability, and appearance. Fabric properties were tested before and after the

hydroentanglement process.

The experimental design was conducted to optimize testing, material selection, and

process parameters. For the purpose of the experimental model, process parameters

include speed, pressure, and number of manifold passes as the main factors of study

related to hydroentangling. The initial fabric selection included six fabric configurations:

100% cotton single knit, 100% cotton double knit, 100% polyester single knit, 100%

polyester double knit, 65/35 polyester/ cotton single knit, and 65/ 35 polyester/ cotton

double knit. From the model, the process parameters were optimized based on data

provided from testing to achieve a desirable fabric. Pilling, abrasion, air permeability,

thickness, weight and stiffness were investigated as primary testing parameters.

Hydroentanglement Process as a Finishing Treatment for the Enhancement of Knitted Fabrics

BY

Stephannia P. Williams

A thesis submitted to the Graduate Faculty of North Carolina State University in partial fulfillment of the requirements for the Degree of Master of Science

Textiles

Raleigh, NC

March 9, 2006

APPROVED BY:

Dr. Benham Pourdeyhimi (Chair of Advisory Committee)

Dr Timothy Clapp (Advisory Committee Member)

Dr. William Oxenham (Advisory Committee Member)

Biography

Stephannia P. Williams graduated with a Bachelor of Science in Industrial Engineering

from Southern Polytechnic State University in Marietta, Georgia in 2002. She gained

professional experience from Milliken & Company as an engineer, which presented her

with the opportunity to further her education at North Carolina State University.

Conducting research as an Institute of Textile Technology Fellow and a Nonwovens

Cooperative Research Center student, Stephannia was awarded a Master of Science

degree in Textiles in 2006.

ii

Acknowledgements

I would like to thank Dr. Behnam Pourdeyhimi for his tireless efforts to educate and

support future leaders. His boundless energy and dedication has helped shape the

nonwovens industry. Dr. William Oxenham and Dr. Timothy Clapp, both experts in

their fields, have also provided an invaluable amount of support and knowledge

throughout the duration of this research.

There are many people that made this experience a memorable one at North Carolina

State University. I would like to acknowledge the outstanding efforts of the Nonwovens

Cooperative Research Center team: Mr. Stephen Sharp, Mr. Alvin Fortner, Mr. Ben

Lambert, Mr. Sherwood Wallace, Ms. Amy Minton, Mr. William Barnes, Mrs. Wendy

Cox, and Mrs. Sue Pegram. I would like to thank the Institute of Textile Technology

team for their support and expertise including: Mr. Chris Moses, Mrs. Patrice Hill, Dr.

Lei Qian, Mrs. Kerry Nasipac, Mrs. Merisa Velebir, Dr. Henry Boyter, Jr., Mr. Shiqi Li,

and Dr. Gilbert O’Neal. I would also like to acknowledge the faculty and staff of North

Carolina State University including: Mrs. Kate Ryan, Mrs. Jan Pegram, Dr. Banks Lee,

Mr. Jeff Krauss, Mr. Robert Cooper, Dr. Chuck Mooney, Dr. Brent Smith, and Dr.

Blanton Godfrey.

I would like to thank Ms. Paige Kennerly for her support and understanding. A special

thank you goes to Mr. Roger Milliken for supporting the textile community and for

making this experience possible. At Milliken & Company I would to thank Mrs. Patsy

Hammett, Mrs. Jodee Dailey, Mr. Ray Ridgeway, Dr. David Moody, Mr. Joe Waddell,

Mr. Chris DeSoiza, Mr. Kevin Carpenter, Mr. Mike Swofford, Ms. Amanda Goodwin, Mr.

James Glenn, Mrs. Jessica Handy, Mr. Tommy Campbell, Mr. Jeff Thacker, Mr. Don

Wall, Mr. John Hickey, Mr. Jeff Gaffney, and Mr. Tony Miller.

I would like to thank my family Ms. Pam Williams, Mr. Patrik Williams, Mr. Stephen

Williams, Mrs. Christine Williams, Ms. Emma Williams, and Ms. Ellie Williams for always

being there for me.

iii

Table of Contents List of Figures..................................................................................................................vi List of Tables...................................................................................................................ix 1 Introduction ............................................................................................................ 1

1.1 Specific Objectives .................................................................................................... 1 1.2 Value of Research ...................................................................................................... 2

2 Literature Review ................................................................................................... 3 2.1 Hydroentanglement Technology ........................................................................... 3 2.2 Face Finishing............................................................................................................. 5 2.3 Characterization of Fabric Pilling .......................................................................... 8 2.4 Pilling Formation ...................................................................................................... 10 2.5 Knitted Fabrics and Processing .......................................................................... 13 2.6 Pill Prevention........................................................................................................... 15

3 Discussion of Experimental Methodology ......................................................... 16 3.1 General information................................................................................................. 16 3.2 Process Characterization ...................................................................................... 17 3.3 Experimental Design ............................................................................................... 19 3.4 Physical Testing ....................................................................................................... 21 3.5 Equipment Considerations.................................................................................... 24

4 Results and Discussion....................................................................................... 25 4.1 Cotton Single............................................................................................................. 25 4.2 Cotton Double ........................................................................................................... 25 4.3 Polyester Single ....................................................................................................... 26 4.4 Polyester Double ...................................................................................................... 27 4.5 Blend Single .............................................................................................................. 28 4.6 Blend Double............................................................................................................. 28 4.6.1 Abrasion Resistance ........................................................................................... 29 4.6.1.1 Single Cotton..................................................................................................... 31 4.6.1.2 Double Cotton ................................................................................................... 32 4.6.1.3 Single Polyester ............................................................................................... 33 4.6.1.4 Double Polyester .............................................................................................. 34 4.6.1.5 Single Blend ...................................................................................................... 35 4.6.1.6 Double Blend..................................................................................................... 36 4.6.1.7 Abrasion Resistance Discussion................................................................. 37 4.6.2 Pilling Resistance ................................................................................................ 37 4.6.2.1 Single Cotton..................................................................................................... 38 4.6.2.2 Double Cotton ................................................................................................... 39 4.6.2.3 Single Polyester ............................................................................................... 40 4.6.2.4 Double Polyester .............................................................................................. 41 4.6.2.5 Single Blend ...................................................................................................... 42 4.6.2.6 Double Blend..................................................................................................... 43 4.6.3 Scanning Electron Micrographs ...................................................................... 44 4.6.3.1 Single Cotton..................................................................................................... 44 4.6.3.2 Double Cotton ................................................................................................... 45 4.6.3.3 Single Polyester ............................................................................................... 45

iv

4.6.3.4 Double Polyester .............................................................................................. 46 4.6.4 Weight ..................................................................................................................... 46 4.6.4.1 Single Cotton..................................................................................................... 47 4.6.4.2 Double Cotton ................................................................................................... 48 4.6.4.3 Single Polyester ............................................................................................... 49 4.6.4.4 Double Polyester .............................................................................................. 50 4.6.4.5 Single Blend ...................................................................................................... 51 4.6.4.6 Double Blend..................................................................................................... 52 4.6.5 Air Permeability and Water Vapor Transmission Rate (WVTR)............... 53 4.6.5.1 Single Cotton..................................................................................................... 53 4.6.5.2 Double Cotton ................................................................................................... 53 4.6.5.3 Single Polyester ............................................................................................... 54 4.6.5.4 Double Polyester .............................................................................................. 55 4.6.5.5 Single Blend ...................................................................................................... 56 4.6.5.6 Double Blend..................................................................................................... 57 4.6.6 Stiffness (Length of Overhang in Machine and Cross Direction) ........... 58 4.6.6.1 Single Cotton..................................................................................................... 58 4.6.6.2 Double Cotton ................................................................................................... 59 4.6.6.3 Single Polyester ............................................................................................... 60 4.6.6.4 Double Polyester .............................................................................................. 61 4.6.6.5 Single Blend ...................................................................................................... 62 4.6.6.6 Double Blend..................................................................................................... 63 4.6.7 Thickness ............................................................................................................... 64 4.6.7.1 Single Cotton..................................................................................................... 64 4.6.7.2 Double Cotton ................................................................................................... 65 4.6.7.3 Single Polyester ............................................................................................... 66 4.6.7.4 Double Polyester .............................................................................................. 66 4.6.7.5 Single Blend ...................................................................................................... 67 4.6.7.6 Double Blend..................................................................................................... 67 4.6.8 Consumer Wash Shrinkage .............................................................................. 68 4.6.8.1 Single Cotton..................................................................................................... 68 4.6.8.2 Double Cotton ................................................................................................... 69 4.6.8.3 Single Polyester ............................................................................................... 69 4.6.8.4 Double Polyester .............................................................................................. 70 4.6.8.5 Double Blend..................................................................................................... 71 5 Conclusions................................................................................................................... 71 6 Recommendations and Future Work ...................................................................... 73 7 References ..................................................................................................................... 74 Appendix ................................................................................................................................ 76

v

List of Figures

Figure 1: Pilling Rate of Jersey Fabrics from RS and OE Yarn ..................................... 14 Figure 2: Hydroentangling Equipment Schematic ......................................................... 18 Figure 3: Orifice Specification ....................................................................................... 18 Figure 4: NCRC Hydroentangling equipment ............................................................... 19 Figure 5: Specific Energy Range of Experiment............................................................ 21 Figure 6: Allasso Fuzz and Pilling Interface .................................................................. 23 Figure 7: Single Cotton Performance ............................................................................ 25 Figure 8: Double Cotton Performance........................................................................... 26 Figure 9: Single Polyester Performance........................................................................ 27 Figure 10: Double Polyester Performance .................................................................... 27 Figure 11: Single Blend Performance............................................................................ 28 Figure 12: Double Blend Performance .......................................................................... 29 Figure 13: Control 1 Abrasion ....................................................................................... 31 Figure 14: Sample 4 Abrasion....................................................................................... 31 Figure 15: Sample 6 Abrasion....................................................................................... 31 Figure 16: Control 18 Abrasion ..................................................................................... 32 Figure 17: Sample 22 Abrasion..................................................................................... 32 Figure 18: Sample 23 Abrasion..................................................................................... 32 Figure 19: Control 7 Abrasion ....................................................................................... 33 Figure 20: Sample 10 Abrasion..................................................................................... 33 Figure 21: Sample 12 Abrasion..................................................................................... 33 Figure 22: Control 24 Abrasion ..................................................................................... 34 Figure 23: Sample 26 Abrasion..................................................................................... 34 Figure 24: Sample 28 Abrasion..................................................................................... 34 Figure 25: Control 13 Abrasion ..................................................................................... 35 Figure 26: Sample 15 Abrasion..................................................................................... 35 Figure 27: Sample 16 Abrasion..................................................................................... 35 Figure 28: Control 29 Abrasion ..................................................................................... 36 Figure 29: Sample 31 Abrasion..................................................................................... 36 Figure 30: Sample 33 Abrasion..................................................................................... 36 Figure 31: Control 1 Pilling ............................................................................................ 38 Figure 32: Sample 3 Pilling ........................................................................................... 38 Figure 33: Control 18 Pilling .......................................................................................... 39 Figure 34: Sample 20 Pilling ......................................................................................... 39 Figure 35: Control 7 Pilling ............................................................................................ 40 Figure 36: Sample 10 Pilling ......................................................................................... 40 Figure 37: Control 24 Pilling .......................................................................................... 41 Figure 38: Sample 27 Pilling ......................................................................................... 41 Figure 39: Control 13 Pilling .......................................................................................... 42 Figure 40: Sample 17 Pilling ......................................................................................... 42 Figure 41: Control 29 Pilling .......................................................................................... 43 Figure 42: Sample 33 Pilling ......................................................................................... 43 Figure 43: Micrograph Control 1.................................................................................... 44 Figure 44: Micrograph Sample 6 ................................................................................... 44

vi

Figure 45: Micrograph Control 18.................................................................................. 45 Figure 46: Micrograph Sample 23 ................................................................................. 45 Figure 47: Micrograph Control 7.................................................................................... 45 Figure 48: Micrograph Sample 12 ................................................................................. 45 Figure 49: Micrograph Control 24.................................................................................. 46 Figure 50: Micrograph Sample 28 ................................................................................. 46 Figure 51: Single Cotton Weight ................................................................................... 47 Figure 52: Double Cotton Weight .................................................................................. 48 Figure 53: Single Polyester Weight ............................................................................... 49 Figure 54: Double Polyester Weight............................................................................. 50 Figure 55: Single Blend Weight..................................................................................... 51 Figure 56: Double Blend Weight ................................................................................... 52 Figure 57: Single Cotton Air Permeability and WVTR ................................................... 53 Figure 58: Double Cotton Air Permeability and WVTR.................................................. 54 Figure 59: Single Polyester Air Permeability and WVTR............................................... 55 Figure 60: Double Polyester Air Permeability and WVTR ............................................. 56 Figure 61: Single Blend Air Permeability and WVTR .................................................... 57 Figure 62: Double Blend Air Permeability and WVTR ................................................... 57 Figure 63: Single Cotton Length of Overhang ............................................................... 59 Figure 64: Cotton Double Length of Overhang.............................................................. 60 Figure 65: Single Polyester Length of Overhang........................................................... 61 Figure 66: Polyester Double Length of Overhang ......................................................... 62 Figure 67: Blend Single Length of Overhang ................................................................ 63 Figure 68: Double Blend Length of Overhang ............................................................... 64 Figure 69: Single Cotton Thickness............................................................................... 65 Figure 70: Double Cotton Thickness ............................................................................. 65 Figure 71: Single Polyester Thickness .......................................................................... 66 Figure 72: Double Polyester Thickness......................................................................... 66 Figure 73: Single Blend Thickness................................................................................ 67 Figure 74: Double Blend Thickness............................................................................... 67 Figure 75: Single Cotton Wash Shrinkage .................................................................... 68 Figure 76: Double Cotton Wash Shrinkage ................................................................... 69 Figure 77: Single Polyester Wash Shrinkage ................................................................ 70 Figure 78: Double Polyester Wash Shrinkage............................................................... 70 Figure 79: Double Blend Wash Shrinkage .................................................................... 71 Figure 80: Weight Data ................................................................................................. 77 Figure 81: Air Permeability Data ................................................................................... 78 Figure 82: Pill Rating Data ............................................................................................ 79 Figure 83: Thickness Data ............................................................................................ 80 Figure 84: Wash Shrinkage Data .................................................................................. 81 Figure 85: Mullen Burst Data......................................................................................... 82 Figure 86: Ball Burst Data ............................................................................................. 83 Figure 87: Sled Friction Data......................................................................................... 84 Figure 88: MOCON (WVTR) Data................................................................................. 85 Figure 89: Single Cotton Mullen Burst Strength ............................................................ 86 Figure 90: Double Cotton Mullen Burst Strength........................................................... 86

vii

Figure 91: Single Polyester Mullen Burst Strength........................................................ 87 Figure 92: Single Blend Mullen Burst Strength.............................................................. 87 Figure 93: Single Cotton Coefficient of Friction ............................................................. 88 Figure 94: Double Cotton Coefficient of Friction............................................................ 88 Figure 95: Single Polyester Coefficient of Friction......................................................... 89 Figure 96: Double Polyester Coefficient of Friction ....................................................... 89 Figure 97: Single Blend Coefficient of Friction .............................................................. 90 Figure 98: Double Blend Coefficient of Friction ............................................................. 90

viii

List of Tables

Table 1: Principal Fiber Properties of Pill Formation ..................................................... 12 Table 2: Experimental Design ....................................................................................... 20 Table 3: Performance Parameters ................................................................................ 22 Table 4: Best Abrasion Resistant Samples ................................................................... 37 Table 5: Cotton Single Pill Rating.................................................................................. 38 Table 6: Cotton Double Pilling Rating............................................................................ 39 Table 7: Single Polyester Pilling Rating......................................................................... 40 Table 8: Double Polyester Pilling Rating ....................................................................... 41 Table 9: Single Blend Pilling Rating .............................................................................. 42 Table 10: Double Blend Pilling Rating ........................................................................... 43 Table 11: Fabric Weight Single Cotton.......................................................................... 47 Table 12: Fabric Weight Double Cotton ........................................................................ 48 Table 13: Fabric Weight Poly Single ............................................................................. 49 Table 14: Fabric Weight Poly Double ............................................................................ 50 Table 15: Fabric Weight Blend Single ........................................................................... 51 Table 16: Fabric Weight Blend Double.......................................................................... 52

ix

1 Introduction This report is a summary of the investigation of the literature related to

hydroentanglement as a finishing process for knitted fabrics. Hydroentanglement

describes a versatile process for traditionally manufacturing nonwoven fabrics using

fine, closely spaced, high-velocity jets of water to entangle loose arrays of fibers. The

resultant fabrics rely primarily on fiber-to-fiber friction to achieve physical integrity and

are characterized by relatively high strength, flexibility, and conformability. These

technologies can use efficiently the majority of all types of fibers and produce fabrics

that could achieve properties equivalent to wovens.

The aim of this research is to study the effects of hydroentanglement on knitted fabrics,

to investigate some mechanical and physical properties (such as pilling, abrasion and

handle of the finished textile), and to develop guidelines for optimizing process

parameters to achieve desired results.

1.1 Specific Objectives The specific objectives of this proposal are:

• to summarize literature in the field;

• develop an understanding of the hydroentangling process as a finishing

technique for knitted fabric;

• recommend experimental approaches for characterizing mechanical properties;

• suggest a set of fabric properties that should be investigated for their potential

effects.

This document is intended to support research to develop a series of knitted fabrics and

subject those fabrics to the hydroentangling process to determine the boundaries of the

process-performance interactions. The primary approach is to select process and fabric

factors for a design of experiment and perform analysis of these materials. It is

expected that significant improvements in abrasion and pilling will be attained and the

1

handle of the fabric will be modified. Abrasion resistance, pilling, and strength will be

measured.

1.2 Value of Research Due to growing competition facing the textile industry, knitting manufacturers are faced

with meeting the demands of increasing quality standards while remaining competitive

on cost, creating new niche markets for products by being innovative, and improving on

inherent knitting characteristics. The aim of this research is to provide a solution to the

issues facing the knitting industry. While, this research is not a solution to all of the

issues, it does address the need for innovative products and a means to improve fabric

quality. Knitted fabrics were selected for study over woven fabrics because knitted

fabrics have a greater amount of yarn surface area exposed and a looser structure,

which increase pilling tendency. Based on this fact, knitted fabrics stand to have the

greater improvement with respect to mechanical and physical properties over woven

fabrics.

Nonwoven fabrics are characterized as having good bulk, high absorbency, excellent

tensile strength, high tear strength, good hand, low lint, and excellent durability. It is the

intention of this research to add value to traditional knit fabrics used in apparel

applications. Hydroentangling is generally characterized as having high operating

speeds, low manufacturing costs, as well as added value and innovative. It is not the

intention to replace knitted fabrics with nonwoven fabrics but to marry the two processes

together to create engineered fabrics.

Prior attempts have been made to reduce pilling. Antipilling techniques have included

various methods of reducing the pilling tendency of a fabric using chemical or other

process modifications, the need exists for a simpler and more effective finishing method

for producing fabrics that have a lower tendency to pill as well as having improved

abrasion resistance. Pilling is a serious problem of the textile industry. A finished fabric

may have pleasing handle and a clean surface, but when converted into garments, pills

are formed during wearing as well as washing, due to rubbing action. This research

2

hopes to provide an alternative for the textile industry to increase pilling and abrasion

resistance.

With the rising popularity of cotton, greater demands for quality have been required as

end-users have become more aware of its negative properties, and therefore many

studies have been reported on the geometry and dimensional properties of knitted

fabrics produced from different kinds of yarns. Although the problem of knitted fabric

shrinkage can be solved to some extent by replacing some cotton with a cotton/

synthetic fiber blend yarn, the severity and longevity of pilling, in turn greatly increases.

Taking this fact into consideration, industry stands to benefit from the effect

hydroentanglement has on cotton, polyester, and cotton/ polyester blend based fabrics.

2 Literature Review Recent Literature on hydroentanglement and characterizing mechanical properties has

been reviewed. The primary focus of this review is to explore current methods for

addressing the shortcomings of knitted fabrics, product development strategies, pilling

and abrasion characterization, and hydroentanglement capabilities.

2.1 Hydroentanglement Technology Hydroentanglement, spunlacing, hydraulic needling, and water jet entangling are all

terms used to describe a versatile process for manufacturing nonwoven fabrics with

fine, closely spaced, high velocity jets of water used to tangle loose fibers. Water jet

entangled fabrics consist of mechanically interlocked fibers and fiber bundles where the

energy is supplied by high pressure streams of water in the form of columnar jets.

The hydroentangling process began in the mid 1960’s at E.I. DuPont de Nemours. The

original intent of the process was to join two bundle ends in the manufacture of

polyester fiber. The process later evolved to convert un-bonded webs of loose fibers

into mechanically strong, durable fabrics. Today several companies produce

hydroentangled fabrics.

3

In the entanglement operation, water is jetted through the orifices in the manifolds into

the web of un-bonded fibers or filaments. The fibers move and tangle as the high

velocity water penetrates the web. The fibers conform to the topography of the support

medium and produce a mirror image of the support structure. If the support medium is

open, the resultant fabric structure is open. If the support medium is closed or planar,

the resultant fabric will appear non-apertured.

The orifice jet is designed to produce a steady stream of water at high pressures and

high velocities. The streams of water perform like needles of a needle loom; however,

the jets are continuously striking the passing web. Often there is a slight pattern in the

forming belt side of the fabric. Fabrics entangled on micro-porous drums show no

pattern on either side of the fabric but jet streaks can occur.

The hydroentangling processes begins with a web source. Virtually any fiber can be

hydroentangled. The web may include many sources such as: carded, carded and

cross-lapped, wet-laid, air-laid, spunbonded, and meltblown webs. The main

mechanics of the hydroentangling process include the following elements of web

support, water, jet entangling, water extraction, water circulation and filtration.

Hydroentangled fabrics can be finished like traditional woven and knit textiles. Printing,

jet dying, pad dyeing, bleaching cotton fabrics, mercerizing cotton fabrics, and heat

setting can all be applied when developing hydroentangled fabric. Because of the

involvement of water in the process, all hydroentangled fabrics must be dried.

Belt, drums, or flat rolls have been used to transport the loose webs into the

hydroentangling system. As stated previously, the carrying structure is reproduced in

the fabric. The manipulation of the water stream through the web gives the fabric its

mechanical properties. The configuration of the support medium can affect the

properties of the finished fabrics. Configurations with rectangular orientations of the

fibers produce fabrics that are relatively stable in the machine and cross machine

directions. Typically the machine direction / cross direction ratio is 2:1. Forming

4

surfaces that are not rectangular produce fabrics with varying degrees of stretch and

recovery. Solid forming surfaces as described by Unicharm and PerfoJet do not provide

a pattern or design in the entangled fabric. However, the ricochet effect of the jet

passing through the web and then bouncing back through the web has been shown to

significantly reduce the amount of entangling energy required to form a fabric.

Energy is transmitted by the impact of the water onto and through the web. Energy is a

combination of the quantity of water and its velocity. Velocity is proportional to the

square root of the pressure. Quantity is the product of the velocity and the area of the

orifice.

Water striking the fibrous web creates contamination. The contamination can consist of

fiber particles, fiber contamination, fiber finish, or system erosion. Contaminations

should be removed to prevent orifice clogging and deterioration. A clogged orifice will

create a jet streak in the fabric that subsequent passes may not erase. Streaks are

inherent in the hydroentangling process but are considered to be defects for most

applications. A variety of systems have been developed for the filtering process of

water. Both Fleissner and PerfoJet use a combination of sand fibers, bag filters, and

final filters. Contamination levels of less than 1 ppm are desired.

2.2 Face Finishing Several U.S. patents have been granted or filed pertaining to enhancing the physical

and mechanical properties of fabrics using hydroentangling. The abstracts of such

patents are summarized throughout this section.

Given the undesirable nature of a fabric that is subject to pilling, several industrial

means have previously been employed in order to prevent such generation of pills. For

example, U.S. Patent No. 3,975,486 to Sekiguchi et al., filed in 1973, is directed to “a

process for producing an antipilling acrylic fiber wherein the steps of coagulation,

stretching and relaxing heat treatment are conducted under particular conditions.”

5

Likewise, U.S. Patent No. 4,205,037 to Fujimatsu , filed in 1978, is directed to “acrylic

synthetic fibers highly resistant to pilling and having good dyeability produced by

specifying the composition of the acrylic polymer, the condition of the primary stretching

step, the internal water content of the water-swollen gel fibers, and the conditions of the

steps of the drying–compacting, secondary stretching and relaxing heat treatment.”

Additionally, U.S. Patent No. 6,051,034 to Caldwell is directed to “a method for reducing

pilling of cellulosic towels wherein a composition comprising an acidic agent, and

optionally a fabric softener, is applied to a pillable cellulosic towel, preferably to the face

yarns of the towel. The towel is then heated for a time and under conditions sufficient to

effect a controlled degradation of the cellulosic fibers, thereby reducing pilling.”

In the past, various efforts have been directed at improving the dimensional stability and

physical properties of woven and knitted fabrics through the finishing step of

hydroentanglement. In such applications, warp and filling fibers in fabrics are

hydroentangled at crossover points to effect enhancement in fabric cover.

For example, U.S. Patent No. 4,695,500 to Dyer et al. is directed to a “loosely

constructed knit or woven fabric that is dimensionally stabilized by causing staple length

textile fibers to be entangled about the intersections of the yarns comprising the fabric.

The stabilized fabric is formed by covering one or both sides of the loosely constructed

base fabric with a light web of the staple length fibers, and subjecting the composite

material to hydraulic entanglement while supported on a porous forming belt configured

to direct and concentrate the staple length fibers at the intersections of the yarns

comprising the base fabric.”

U.S. Patent No. 5,136,761 to Sternlieb et al. is directed to an “apparatus and method for

enhancement of woven and knit fabrics through the use of dynamic fluids which

entangle and bloom fabric yarns. The process includes a two stage enhancement

process wherein top and bottoms sides of the fabric are respectively supported and

impacted with a fluid curtain included high pressure jet streams. The controlled process

6

energies and use of the support members having open areas which are aligned in offset

relation to the process line produces fabrics having a uniformed finish and improved

characteristics including edge fray, drape, stability, abrasion resistance, fabric weight

and thickness.”

U.S. Patent No. 5,761,778 to Fleissner is directed to a “method for hydrodynamic

entanglement or needling, preferably for binder-free compaction, of fibers of a fiber web,

especially a nonwoven fiber web, composed of natural or synthetic fibers of any type,

wherein the fibers of the fiber web are entangled and compacted with one another by a

plurality of water streams or jets applied at high pressure, with a large number of the

water streams or jets striking the fiber web not only in succession but also several times

on alternate sides of the web for optimum twisting of the fibers on the top and bottom on

the fiber web. “

U.S. Patent No. 6,557,223 to Greenway et al. is directed to “improvements in

hydroenhancement efficiency obtained by operating a manifold in relative movement to

fabric transported under the manifold so as to deliver a low energy to the fabric per pass

in multiple passes on the fabric. This process results in greater enhancement efficiency

and reduced pilling."

Finally, U.S. Patent Application No. 60/529,490, filed December 15, 2003, provides a

method for “reducing the surface pilling tendency and improving resistance of a pillable

fabric. The methods include providing a pillable fabric including fibrils extending from

the surface, supporting the fabric, and exposing the fabric to a hydroentanglement

process that imparts an energy in the range of 4000 to 5000 KJoules/Kg of fabric using

pressures of 200 bars or greater. The presence of fibrils on the fabric surface are

reduced to an amount wherein the pilling production on the fabric is less than about

20% after 5,000 cycles of abrasion on a Martindale device according to ASTM D4970

testing standard and the fabric remaining mass is at least about 80% to 90% after

50,000 cycles of abrasion on a Martindale device according to ASTM D4966 testing

standard.”

7

While these prior art hydroentanglement finishing processes have been directed to

improving dimensional stability and physical properties such as edge fray and drape

and abrasion resistance, there remains a need to better reduce the pilling tendency and

better improve abrasion resistance of a pillable fabric utilizing a physical finishing

method that can be employed based upon specific process parameters for generation of

an antipilling fabric.

2.3 Characterization of Fabric Pilling Pilling is a fabric surface flaw in which small bundles of entangled fibers cling to the

fabric surface by one or more surface fibrils. Pilling is typically preceded by fuzz

formation and when the material is subject to physical stimulation such as friction, the

fuzz clumps together and is gathered by the fibrils. The phenomena are undesirable

because it gives the fabric a worn appearance and generally lowers the commercial

value of the fabric. Pills ultimately break off of the surface. Pilling is a characteristic of

mainly woven and knitted fabrics, and fuzz is more common in nonwovens. In

nonwoven fabrics, abrasion results in the formation of more nonpillable fuzz than

pillable fuzz because of the limitation of available fiber lengths by the presence of the

bond sites. Nonwoven fabrics tend to tear before pills form.

Many test methods have been developed to evaluate pilling, but none can detect pills

conveniently and objectively or describe them comprehensively . Objective and reliable

methods are needed to estimate the effects of both fabric structure and abrasion related

variables on fuzz and pill formation. Image analysis techniques have been used in an

attempt to determine the pill grade instead of the historic method of comparing pill

images with the corresponding images of a set of standard photographs . The

previously described method uses a laser together with an x – y stage to measure the

distance from the laser to the fabric surface, thereby creating a height map (image) of

the surface. A major advantage of this method is that it does not depend on illumination

and measures the true surface character of the fabric. The method is however, slower

and more expensive than most optical systems that are currently available. To

8

objectively identify and estimate both fuzzing and pilling, a method has been developed

that is capable of assessing changes easily and reliably. This is accomplished by

controlling the angle of incident light such that only objects raised from the surface are

illuminated.

The laser method determines the geometric figures of the pill objects, including density

(referring to the total number of pill elements in the same area of the sample) and pill

element size (pill area fraction), expressed as a percentage of the total area examined.

The system uses a ring light and a cylindrical reflector to illuminate the sample by

transmitting a narrow band of light at the desired angle. The light angle and the

distribution can be modified by changing the radius of the cylindrical reflector and/or the

distance of the ring light to the sample. The angular spread of the incident light needs

to be less than 10 degrees. The amount of light scattered by the pill will be relatively

high, resulting in significant contrast in the final image.

There are several different pilling testers available, the Martindale wear and pilling

tester, the ICI pilling box, and the random tumble pilling tester. The kind of pilling tester

has a significant effect on test results. A study was conducted by Goktepe to determine

which tester is more appropriate for given fabric and yarn types. Cooke and Goksoy

compared the results of the pilling box, Martindale, and the accelerator testers and

reported that the Martindale and accelerator gave reliable results, while the results of

the ICI’s pilling box may be misleading. Samples containing more polyester pilled more

compared to fabrics with less polyester according to the box and the drum results

(Goktepe). However, in this situation, the Martindale could not detect any difference

between these samples. When yarn count changed, there was no difference in the box

and drum results, while the Martindale results indicated that there was more pilling as

yarns became coarser. There was a difference in the pilling of bi-stretch and mono-

stretch fabrics. The bi-stretch fabric pilled less according to all three testers.

9

2.4 Pilling Formation There are many factors of fiber, yarn, and fabric construction which relate to pilling.

Pilling depends on the rate of:

• surface fiber fuzz formation

• fuzz entanglement

• pill wear off

Pilling is promoted by a number of factors such as fiber length, denier, twist, hairy,

coarseness of yarns, type of fabric construction, and type of finish. Pill formation is a

dynamic process in which pills are constantly formed and wear off. If the formation rate

is greater than the break off rate, then pills build up on the surface. Any factor which

allows fibers to migrate to the yarn surface will increase the formation rate.

Pilling is considerably influenced by fiber dtex. Rigidity and stiffness increase as the

dtex increases. This inhibits fiber migration and entanglement and minimizes pilling.

There will be less fiber ends per given cross section of yarn to form fuzz and there are

also less fibers with which pills can anchor. It is noted by Dr. Nilgun Ozdil, that finer

yarn involves a high degree of pilling for knitted fabrics. The reason being is, that

coarse yarns produce a tight fabric structure, whereas finer yarns create a slack fabric

structure; therefore, the tendency to pilling increases.

The longer the staple length, the lower the pilling tendency, because there are fewer

fiber ends protruding per unit area. Also, long fibers can be more firmly secured to the

yarn. An increase in fiber length presents less fiber ends to form fuzz and fiber

migration is reduced due to increased frictional contact between the longer fibers when

twisted together. This is not the most important contributor to pilling and a major

change in fiber length is required to achieve a significant difference in pilling resistance.

Fibers having a non-circular or multi-lobal cross section usually pill less than those

which have a round cross section. Non-circular fibers are generally stiffer and in many

10

cases inter-fiber friction is increased leading to a reduction in fiber migration and

entanglement properties. A circular cross section with a smooth fiber surface allows the

fiber to migrate to the surface of a fabric and form pills. Therefore, irregular cross

sections reduce pilling. This is not a primary factor effecting pilling.

Cotton and cotton blend woven and knitted fabrics have a great tendency to generate

pills. Fiber strength is the most important fiber property effecting pilling, particularly with

synthetic fibers which are usually manufactured stronger than the minimum required for

apparel wear. The lower the strength, the greater the wear off of the initial fiber fuzz

before entanglement. Pilling can be controlled to a considerable extent therefore

reducing the strength of the fiber so that the pill wear off dominates pill formation. The

basis of all commercial low pill polyester fiber is reduced strength. This may be

achieved by reducing the tenacity or reducing the I.V. (a function of molecular chain

length and or weight).

Flexural rigidity is a function of decitex, cross section and stress/strain curve of the fiber,

and consequently has a considerable influence on pilling. The stiffer the fiber the more

migration and entanglement will be inhibited and the less will be the potential pilling.

The flexibility of polyester fibers is closely associated with fiber I.V. and tenacity. When

the I.V. is reduced, the flex life and associated durability are rapidly reduced. This is an

important point when considering the acceptability of certain fibers for different end

uses.

Fiber friction is an important property and has a considerable influence on fiber

migration. The greater the inter-fiber friction, the more migration will be prohibited and

the less likely for formation of fuzz and potential pilling sites. Modification of this

property is widely used as an anti-pilling technique in finishing.

Generally, the higher the amount of crimp, the less pilling occurs. The inter-fiber friction

is increased and crimp damage causes tenacity variations along the fiber. Weak points

are made at the crimp apices where maximum deformation of the fiber has taken place.

11

Thus pill anchoring fibers break off more easily particularly when subjected to a caustic

treatment during finishing.

Filament fibers have excellent pilling resistance compared to staple fibers. Filaments do

not abrade and break easily and therefore cannot migrate on the surface, whereas for

short staple fibers, friction during wear and washing easily brings the fibers to the

surface, leading to pill formation. Pills can form for any staple fiber, whether synthetic or

natural.

Natural and synthetic fibers have very different properties and pilling is influenced

considerably by the type of fiber used. All fibers including wool, cashmere, and human

hair pill to some degree, sometimes for different reasons. Table 1 outlines the chief

properties of the main fiber groups and indicates the probable pilling propensity of some

of the fibers within each group.

Table 1: Principal Fiber Properties of Pill Formation

The rate of pill formation of standard polyesters and polyamides greatly exceeds the

rate of pill wear off, whereas the rate of pill formation of some low pill polyesters and

protein fibers is usually exceeded by the rate off pill wear off.

12

The higher the twist, the lower the fiber migration and fuzz formation. However, if a

significant difference in pilling is to be achieved, the twist must be increased to such a

level that the fabric aesthetics are usually completely unacceptable for apparel wear.

Very little advantage can be taken of this concept except to ensure that yarns are not

under twisted.

Due to the fibers being more parallel, open end yarns are not as hairy as ring spun

yarns. Consequently, initial fuzz is less and pilling should be reduced. In practice,

however the fibers form loops which are easily teased out from the body of the fabric

when abraded and consequently the reduction in pilling is not as great as might be

expected. Initial hairiness associated with yarn spun on conventional spinning systems

can increase with: spindle speed, incorrect spinning traveler, and excessive contact with

balloon control rings. Correct spinning conditions therefore are an integral part in

minimizing fuzz formation and pilling potential.

The higher the yarn density (cover factor) and the tighter the construction, the less

chance the fibers have for movement. Shorter floats and stitch lengths also help to

restrict fiber movement and subsequent pilling.

Increasing the weight of knitted fabrics helps to reduce pilling presumably by tightening

up the construction and making fiber migration more difficult. Weight changes do not

generally affect pilling of woven fabrics to the same extent. Fabric weight is not as

important a factor in the control of pilling principally due to end use limitations.

2.5 Knitted Fabrics and Processing It is well known that a series of factors affect the pilling properties of fabrics. The yarns

produced by different spinning systems are expected to impact the pilling resistance of

fabrics, because there are significant differences between the structures. According to

W.D. Cooke, hairiness, low yarn twist and slack fabric structure were reported to favor

fiber fuzz, roll up, and pilling entanglements. There is conflicting evidence to support

which yarn formation process improves pill resistance. Research presented

13

momentarily suggest that open end yarn pills less than ring spun yarn. However, there

is evidence that Open end yarns create more pilling than ring spun yarns.

In a study conducted by Dr. Nilgun Ozdil, the pilling resistance of fabrics knitted from

100% cotton open end and ring spun yarns was investigated and the effects of the

spinning system on the pilling behavior of the knitted fabrics were explained. Open end

yarns have a twisted core and a loosely wrapped sheath with trailing loops, while ring

spun yarns are well aligned along the axis. Ring spun yarns have excellent fiber

orientation. Consequently the strength of ring spun yarn is 15 – 20% higher than open

end spun yarn. Ring spun yarns are also 20- 40 % hairier than open end yarns

according to E. Steffes and W. Schlafhorst.

Using a Martindale pilling and abrasion tester, the test samples were evaluated at 500,

1000, 2000, and 5000 cycles respectively. Testing revealed that there is a significant

difference in the spinning techniques, but the significance decreases at 5000 cycles. At

5000 cycles the differences between ring spun and open end yarn fabrics decreased as

far as pilling rates are concerned. It was found that the open end yarns are more pill

resistant than ring spun yarns. More breakages and entanglements occurred on ring

spun yarn fabrics.

0

0.5

1

1.5

2

2.5

3

3.5

4

500 1000 2000 5000Revolution

Pill

Rat

ing

ring spunopen end

Figure 1: Pilling Rate of Jersey Fabrics from RS and OE Yarn

14

The research concluded that ring spun yarns may be less pill resistant due to the fact

that the yarn is hairier and more compactly structured than open end yarns. The yarn

hairiness was verified by conducting a Uster Yarn Evenness test. Ring spun yarns are

hairier because of the fibers that partly protrude from the yarn center. This structure

causes fiber fuzz, because the protruding fibers easily affect the abrasion strength.

Also, the well aligned compact structure of ring spun yarns does not allow easy fiber pull

out and fuzz removal and, therefore, also contributed to the lower pilling ratings (severe

pills).

A study was conducted by Okubayashi et al, to determine the effects of wet processing

on the pilling mechanism of cellulosic knit fabrics. The length of fuzz and pill after

washing and drying treatments was determined by electrical resistivity, detected by an

apparatus constructed with a thickness meter. The degree of fuzz and pill formation

was related to the corresponding fiber – fiber friction in dry and wet conditions. The

experiment suggests that the end of the fiber comes out from the yarns by mechanical

abrasion due to low fiber – fiber friction. The fuzz then entangles owing to the softness

and the high fiber – fiber friction when swollen with water, thus resulting in pills.

2.6 Pill Prevention There are several methods adapted to reduce pilling before, during, and after

manufacture processing. Some of the methods are chemical, mechanical, or involve

designed engineering to reduce pilling.

Initially, fibers can be selected to reduce pilling. Manufacture yarn and fabric based on

low pilling tendencies. During manufacturing, prevent abrasion during batch processing

by using suitable lubricating agents, as abrasive mechanical action increases pilling.

Use proper heat settings for polyesters and cellulosic blends. Some chemical means of

reducing pilling involve using biopolishing enzymes for cotton and polyester cotton

blends. Using optimum concentrations of silicone softeners to avoid excessive softness

and lubricity, which otherwise could promote migration of fibers on to the surface. Films

can be applied to the fabric during finishing to improve pilling.

15

There are several mechanical means to reduce pilling. Shearing with brushing

techniques help eliminate surface fibers and protruding fibers. Singeing on both

surfaces removes surface fibers. The removal of surface fibers results in decreased

pilling.

3 Discussion of Experimental Methodology 3.1 General information A specific objective of this research project was to characterize the properties of knitted

fabric after being subjected to hydroentangling in the finishing stages. The approach

was to explore an experimental analysis of knitted fabric properties and hydroentangling

process variables coupled with empirical modeling.

The focus of this document was the experimental component of this project.

Experimentation was necessary for completion of simulation work. Any models created

were validated with data. Physical characterization of the fabric was conducted to

provide information for simulation of representative fabric.

This section contains suggested routes for the achievement of the project goals. The

specific topics covered in this section include:

• viable options for characterization of process properties;

• suggested material characterizations;

• recommended experimental approach and prioritization.

In several instances, specific decisions related to experimental approach depended

greatly on the findings of the team, the specific materials available for study, and

preliminary experimentation.

16

3.2 Process Characterization Specific information was needed to validate models of real materials. The initial

decision was to determine the systems to model and analyze. The description of an

experimental system include the:

• type of material structure;

• yarn formation;

• manifold pressure;

• fiber type;

• basis weight;

• number of manifold passes;

• process speed; and

• substrate.

For practical requirements of simulation and measurement, the experiment was limited

to extreme factors within feasible limits. The type of material structure was of critical

importance. For the basis of this experiment the material structure included single knit

jersey and double knit interlock configurations. Fiber type was of equal importance.

The experiment was designed around using ring spun cotton, ring spun polyester, and

ring spun 65/35 polyester/ cotton blend. The yarn was selected on the grounds of

availability, structure, and industry usage. The yarn count in the indirect system was

targeted at 20/1, but varies between 18.5/1 and 22/1 based on availability. The yarn

was classified as 18.5/1 cotton, 20.5/1 T-811 polyester, and 22/1 65/35 T-567

polyester/cotton.

The three yarns were knitted into jersey and interlock constructions using circular knit

technology. The yarns were tested for weight, evenness, and tenacity based on

existing standards. The results were comparable to the manufacturer’s specifications

and thus were considered to be first quality yarns. The control fabric was defined as

fabric that has not been processed after knitting. The control fabrics were tested in the

same manner as the sample (or hydroentangled) fabrics and are comparable to the

17

manufacture’s specifications. Thus the control fabric is considered to be first quality

fabric.

The aim of this experiment is to simulate optimized process parameters that are

conducive to industry practices. Fleissner hydroentangling equipment was used to

conduct the experiments. The equipment is characterized by having five manifolds,

each capable of achieving 400 bar of pressure. The fabric was supported by a flat belt

and drum configuration and allows for fibers to be entangled on the face side, the back

side or both. The belt and drum

velocity was capable of reaching

up to 400 meters per minute.

The belt and drum width was

limited to 24 inches in the

machine cross direction and the

belt was 103 mesh comprised of

polyester. BELT

FABRIC

DRUMMANIFOLDS

MANIFOLDS

BELT

FABRIC

DRUMMANIFOLDS

MANIFOLDS

FABRIC

DRUMMANIFOLDS

MANIFOLDS

Figure 2: Hydroentangling Equipment Schematic

Due to the width limitation of 24 inches in the cross

direction of the hydroentangler, the fabric was further

processed. The original knitted fabric was in tubular

form 64 inches in diameter. The fabric was slit so that

24 inch open width panels remained. The remaining

selvages were discarded. The hydroentangler also

required at least 40 yards of fabric to properly feed the

fabric through the process.

Figure 3: Orifice Specification

The jet strips used in this experiment are identical for each manifold and are

characterized as having 40 holes per inch. Each orifice is 120 microns or 0.12

millimeters in diameter as the figure indicates. The first jet strip located in the first

18

manifold has a cone up configuration and the remaining jet strips have a cone down

configuration as indicates. The cone up configuration is to pre-wet the fabric and thus,

the first manifold position customarily is set at a lower pressure compared to the

remaining manifolds. Much research has been conducted on hydroentangling process

parameters and jet strip configurations.

Figure 4: NCRC Hydroentangling equipment

3.3 Experimental Design The experiment consisted of 33 samples comprising of three different yarn types and

two fabric constructions as indicated in Table 2.

The 33 trials vary by fabric, speed, pressure, and number of passes the fabric was

hydroentangled. Samples 1, 7, 13, 18, 24 and 29 are the control samples. Those

samples were not hydroentangled as the table indicates that the process parameters

are zero. The fabric is comprised of 6 fabric types. Three yarns made up of 100%

cotton, 100% polyester, and 65/35 polyester / cotton are referred to as cotton, poly, and

blend respectively in the above table. Each of the three yarns was knitted into a jersey

and interlock construction referred to as single and double respectively.

19

Table 2: Experimental Design

TRIAL KNIT

CONSTRUCTION FIBER TYPE

SPEED M/MIN

PRESSURE BAR

NUMBER OF PASSES

1 CONTROL 0 0 0 2 SINGLE COTTON 50 100 1 3 SINGLE COTTON 50 100 2 4 SINGLE COTTON 50 220 3 5 SINGLE COTTON 10 220 1 6 SINGLE COTTON 10 220 3 7 CONTROL 0 0 0 8 SINGLE POLY 50 100 1 9 SINGLE POLY 10 100 1 10 SINGLE POLY 50 220 1 11 SINGLE POLY 10 220 1 12 SINGLE POLY 10 100 2 13 CONTROL 0 0 0 14 SINGLE BLEND 50 100 3 15 SINGLE BLEND 50 220 1 16 SINGLE BLEND 10 100 3 17 SINGLE BLEND 10 220 2 18 CONTROL 0 0 0 19 DOUBLE COTTON 50 100 1 20 DOUBLE COTTON 50 100 3 21 DOUBLE COTTON 10 100 1 22 DOUBLE COTTON 10 220 1 23 DOUBLE COTTON 10 220 2 24 CONTROL 0 0 0 25 DOUBLE POLY 50 220 1 26 DOUBLE POLY 50 220 3 27 DOUBLE POLY 10 100 2 28 DOUBLE POLY 10 220 3 29 CONTROL 0 0 0 30 DOUBLE BLEND 50 220 1 31 DOUBLE BLEND 10 100 3 32 DOUBLE BLEND 10 220 1 33 DOUBLE BLEND 10 220 2

The belt speed or processing speed was set at 10 or 50 meters per minute. The

pressure was set at 100 or 220 Bar. To achieve higher specific energy, the fabric was

hydroentangled either 1, 2, or 3 passes. Figure 5: Specific Energy Range of

Experiment graphically details the specific energy each fabric received. Sample 1 was

the control sample and received no energy. As the sample number increases, the

20

amount of specific energy increases. For example, looking at sample 2 up to sample 6,

energy increased from 478 to 22740 KJ/KG respectively. Specific energy takes fabric

weight into consideration. Because the double knit fabrics are heavier in weight, the

specific energy for those fabrics is lower.

0

5000

10000

15000

20000

25000

30000

35000

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33

KJ/

KG

SINGLE COTTON SINGLE POLYESTER SINGLE BLEND DOUBLE COTTON DOUBLE POLYESTER DOUBLE BLEND

Figure 5: Specific Energy Range of Experiment 3.4 Physical Testing Table 3 lists the material characteristics recommended for measurement during this

study. A short description of a likely test method (or source thereof) is included.

Testing was conducted in several phases: post yarn formation, post knit, and post

hydroentangling. After yarn formation, weight, evenness and tensile testing was

conducted. The tests were conducted on the controlled and sample fabrics, and all

tests were conducted in a manner consistent with industry accepted standards.

For each fabric type, the samples were compared to the control to detect any

improvements or deteriorations. The samples were also evaluated to indicate if the

processing parameters (pressure, speed, and passes) had any impact on the fabrics

and if so, the significance of that impact.

21

Test Equipment Units Standard1 Abrasion Resistance Nu Martindale Weight Loss % ASTM D4966-042 Air Permeability Cubic Feet per Minute ASTM D737-963 Basis Weight Grams/Square Meter ASTM D3776-964 Burst Ball/ Constant Rate Traverse Poundforce ASTM D3787-015 Burst Hydraulic/ Diaphragm Pounds per Square Inch ASTM D3786-016 Count Ends/ Picks per Inch ASTM D 3887-047 Friction Instron INDA IST 140.1-958 Pilling Optical ASTM D 49709 Pilling Random Tumble ASTM D 3512-02

10 Stretch/ Recovery Percentage ASTM D2594-9911 Stiffness Cantilever Millimeters ASTM D1388-0212 Thickness Electronic Thickness Tester Millimeters ASTM D 1777-0213 Wash Shrinkage Consumer Laundering Percentage AATCC 13514 Water Vapor Transmission Mocon Grams / Square Meter Day ASTM D6701-01

Table 3: Performance Parameters

Due to the nature of some tests and knitted fabrics, test results could not be obtained

for every sample. Available results are reported in their entirety throughout this report,

and the exceptions are reported below.

To test abrasion resistance, samples were tested on Martindale equipment at no

energy, medium energy, and high energy. Single knit samples were evaluated for

weight loss at 0, 1000, 3000, and 5000, cycles. The double knit samples were

evaluated for weight loss at 0, 5000, and 10,000. The samples were also evaluated

optically and visually. When evaluating fabric optically, pills appear white in the

photograph because the pills are so dense. The photographs reveal the extent of fuzz

and the size and number of pills.

The samples were evaluated at no energy (the control sample), medium energy (2000

to 5000 KJ/Kg), and high energy (the highest energy for each fabric type). Each sample

was abraded for 5000 cycles and evaluated on percentage of weight loss, rank among

samples, and optically. The percentage of weight loss is calculated by taking the

average of the abraded weight minus the initial weight, divided by the initial weight. A

negative percentage indicates an increase in weight, which is possible in cases where

the sample forms pills with the wool abrasive fabric. Holding the wool to the surface of

the fabric samples causes a slight, but detectible increase in weight. To determine

rank, ten people were asked individually to evaluate the three samples for each fabric

22

type and assign a rank based on the sample’s physical appearance. A sample could be

assigned either a 1, 2, or 3. A sample receiving a 1 was considered to be the best

overall sample, a 3 indicated the worst sample, and a 2 was between the best and worst

case. Lastly, the samples were evaluated optically using an Allasso Optical Tester.

The tester magnifies the fabric surface and indicates pills, fuzz, and other surface

defects as indicated in Figure 6.

Figure 6: Allasso Fuzz and Pilling Interface The software interface enables the operator to view a live image of the test sample and

the respective pilling characterization data all in one screen. The software can be setup

to output the data in comparison to any pictorial standard or use the Allasso Fuzz &

Pilling Index. For the purpose of the abrasion research, the Allasso tester was used to

optically capture the fabric surface. In regard to the pilling research, the fabric surfaces

were captured optically and an Allasso pilling rating was assigned. Typically an Allasso

pilling rating of less than 150 indicates little pilling and values increasing over 150

indicate increasing pill severity.

An attempt was made to test all of the samples on a hydraulic burst tester for burst

strength. All of the double knit fabrics exceeded the limitations of the machine and thus

could not be evaluated. To supplement the loss of data, samples were tested for burst

strength using a ball burst tester. Again, due to the elasticity of the samples, several

single knit samples and all double knit samples failed to burst.

23

To test for stiffness, the fabrics were subjected to tests using the cantilever method.

Hydroentangling reduces the tendency for single knit fabrics to curl. The control fabrics

however, were not hydroentangled, and curled extensively. The results of the cantilever

test for those fabrics were distorted due to the curling of the fabric and thus were not

reported.

Water vapor transmission rate was evaluated at two levels, zero energy and high

energy for each of the fabric types. The assumption was made that hydroentanglement

would not dramatically effect water vapor transmission rates.

3.5 Equipment Considerations Hydroentanglement is a process traditionally utilized to bond or split fibers. Some

considerations must be made in order to process pre-bonded fabrics such as knitted

and woven fabrics. The natural tendency of circular knitted fabric is to curl at the

selvages and distort and shrink in size under the high pressure exerted by the force of

the water. Single knit fabrics are especially prone to the phenomena. When processing

knitted fabrics, if the selvages are unsecured during hydroentangling, the selvages will

turn into the center of the fabric and become bonded to the fabric body creating seams.

It should be noted that the fabric comprising the seams did not receive the same energy

as the body of the fabric and was not used for testing purposes. The fabric curling is

worsened in the winding process preceding hydroentangling.

After processing several hundred yards of fabric, the filtration system became

overwhelmed and caused the system to backwash. The filtration backwash was

attributed to the lint removal from the selvages attributed to the slitting process

necessary to accommodate the fabric. In future processing, considerations should be

made to remove as much lint as possible from the fabric.

24

4 Results and Discussion Each of the six fabric types were evaluated and ranked based on the performance

parameters. Abrasion and pilling resistance were given priority over the remaining

factors. The other performance parameters (weight, air permeability, overhang length,

thickness, wash shrinkage, ball burst strength, friction, and water vapor transmission

rate) were evaluated based on an improvement or deterioration from the control fabric.

Evaluations were based on mean comparisons using statistical analysis.

4.1 Cotton Single Five fabric samples (samples 2 to 6) were compared to control sample 1 for the single

cotton samples. Sample 3 proved to have the best overall performance as highlighted

in Figure 7. Sample 3 was hydroentangled at a low specific energy or 955 KJ/Kg.

Hydroentangling cotton jersey knits at high specific energy (greater than 5000 KJ/Kg)

damages the fibers as is the case with samples 5 and 6. To achieve the optimum

sample at a low level of energy (1000 KJ/Kg), sample 3 was processed at a speed of 50

meters per minute, pressure of 100 Bar, and 2 passes or 10 manifolds. The individual

test results can be found in the following sections.

Figure 7: Single Cotton Performance

4.2 Cotton Double Five fabric samples (samples 19 to 23) were compared to control sample 18 for the

double cotton samples. Sample 20 proved to have the best overall performance as

highlighted in Figure 8. Sample 20 was hydroentangled at a low specific energy or 813

25

KJ/Kg. Hydroentangling cotton double knits at high specific energy (greater than 5000

KJ/Kg) is unnecessary as the performance parameters are not significantly improved

beyond this point. To achieve the optimum sample at a low level of energy (1000

KJ/Kg), sample 20 was processed at a speed of 50 meters per minute, pressure of 100

Bar, and 3 passes or 15 manifolds. The individual test results can be found in the

following sections.

Figure 8: Double Cotton Performance 4.3 Polyester Single Five fabric samples (samples 8 to 12) were compared to control sample 7 for the single

polyester samples. Sample 10 proved to have the best overall performance as

highlighted in Figure 9. Sample 10 was hydroentangled at a medium specific energy or

4305 KJ/Kg. Hydroentangling polyester single knits at high specific energy (greater

than 5000 KJ/Kg) causes the fibers to fuzz, giving the fabric good hand, but may not be

an aesthetically desirable quality. To achieve the optimum sample at a medium level of

energy (4500 KJ/Kg), sample 10 was processed at a speed of 50 meters per minute,

pressure of 220 Bar, and 1 passes or 5 manifolds. The individual test results can be

found in the following sections.

26

Figure 9: Single Polyester Performance 4.4 Polyester Double Four fabric samples (samples 25 to 28) were compared to control sample 24 for the

double polyester samples. Sample 27 proved to have the best overall performance as

highlighted in Figure 10. Sample 27 was hydroentangled at a medium specific energy

or 3457 KJ/Kg. Hydroentangling polyester knits at high specific energy (greater than

5000 KJ/Kg) causes the fibers to fuzz, giving the fabric good hand, but may not be an

aesthetically desirable quality. Fuzzing is not as pronounced in the double knit structure

as it is in the single knit structure. To achieve the optimum sample at a medium level of

energy (4500 KJ/Kg), sample 27 was processed at a speed of 10 meters per minute,

pressure of 100 Bar, and 2 passes or 10 manifolds. The individual test results can be

found in the following sections.

Figure 10: Double Polyester Performance

27

4.5 Blend Single Five fabric samples (samples 14 to 17) were compared to control sample 13 for the

single blend samples. Sample 17 proved to have the best overall performance as

highlighted in Figure 11. Sample 17 was hydroentangled at a high specific energy or

21361 KJ/Kg. Hydroentangling cotton rich blend knits at high specific energy is required

to achieve the desired pilling resistance and abrasion resistance. The high level of

energy is necessary to greatly entangle the protruding fibers into the fabric surface. The

loose fibers on the fabric surface contribute to pilling and pilling is more pronounced

when stronger synthetic fibers are present. Fuzzing is not as pronounced as the 100%

polyester samples. To achieve the optimum sample at a high level of energy , sample

17 was processed at a speed of 10 meters per minute, pressure of 220 Bar, and 2

passes or 10 manifolds. The individual test results can be found in the following

sections.

Figure 11: Single Blend Performance 4.6 Blend Double Four fabric samples (samples 30 to 33) were compared to control sample 29 for the

double blend samples. Sample 33 proved to have the best overall performance as

highlighted in Figure 12. Sample 33 was hydroentangled at a high specific energy or

10681 KJ/Kg. Hydroentangling cotton rich blend knits at high specific energy is required

to achieve the desired pilling resistance and abrasion resistance. The high level of

energy is necessary to greatly entangle the protruding fibers into the fabric surface. The

loose fibers on the fabric surface contribute to pilling and pilling is more pronounced

28

when stronger synthetic fibers are present. Fuzzing is not as pronounced as the 100%

polyester samples. To achieve the optimum sample at a high level of energy, sample

33 was processed at a speed of 10 meters per minute, pressure of 220 Bar, and 2

passes or 10 manifolds. The individual test results can be found in the following

sections.

Figure 12: Double Blend Performance 4.6.1 Abrasion Resistance Abrasion was accelerated using a Martindale Pilling and Abrasion Tester. All of the

samples were evaluated at 5000 cycles, however, there was no indication of holes in

any of the samples. A small sample of fabrics was abraded for 30,000 cycles and there

was still no indication of any holes. For future research, an abradent other than wool

should be explored. Given that the number of cycles to develop a hole could not be

determined, the percentage of weight loss was evaluated instead. However, the

samples showed no significant weight loss. Three samples for each fabric type were

ranked. A rank of 1 was given to the best of the three samples and a rank of 3 was

given to the least desirable sample. Also, the percentage of people that agreed with the

ranking are listed. The rankings and optical pictures are discussed in the following

sections.

Fabric construction and fiber type play a significant role in abrasion resistance. When

performing the abrasion tests, fibers at the fabric surface are mechanically aggravated.

The looser the fabric construction (single knit) the easier it is for surface fibers to move.

29

Tighter fabric constructions (double knit) hold the fibers in place and restrict fiber

movement. The available surface fibers determine whether the fabric will form a hole or

pill. Fabrics constructed from weaker fibers, such as 100% cotton tend to break away

from the fabric surface and form a hole. Fabrics constructed from stronger fibers (100%

polyester and polyester blends) tend to form pills on the fabric surface.

30

4.6.1.1 Single Cotton

Control 1: Rank 3 – 90% Sample 4: Rank 2 – 60% Sample 6: Rank 1 – 60% Figure 13: Control 1 Abrasion Figure 14: Sample 4 Abrasion Figure 15: Sample 6 Abrasion

Control sample 1 when abraded, formed pills on the fabric surface. Those pills

contributed to the undesirable ranking. The optical pictures and rankings of samples 4

and 6 indicate that hydroentangling does improve the fabric surface with respect to

abrasion resistance. However, there is little improvement as energy is increased.

Sample 4 and 6 had the same process parameters (220 Bar and 3 passes) except for

speed (50 meters per minute and 10 meters per minute respectively). This information

suggests that the lower energy levels are optimum to achieve increased abrasion

resistance over the control sample.

When visually ranked, 90% of the graders agreed control 1 had the worst overall

surface appearance. Sample 6 was given the best rank with 60% agreement; however

the fibers were damaged as a result of the high pressure (220 Bar).

31

4.6.1.2 Double Cotton

Control 18: Rank 3 – 100% Sample 22: Rank Tie – 50% Sample 23: Rank Tie – 50%

Figure 16: Control 18 Abrasion Figure 17: Sample 22 Abrasion Figure 18: Sample 23 Abrasion

Control sample 18 when abraded, formed pills on the fabric surface. Those pills

contributed to the undesirable ranking. The optical pictures and rankings of samples 22

and 23 indicate that hydroentangling does improve the fabric surface with respect to

abrasion resistance. However, there is little improvement as energy is increased.

Sample 22 and 23 had the same process parameters (220 Bar and 10 meters per

minute) except for passes (1 and 2 passes respectively). This information suggests

that the lower energy levels are optimum to achieve increased abrasion resistance over

the control sample.

When visually ranked, 100% of the graders agreed control 1 had the worst overall

surface appearance. There was no discernable difference between samples 22 and 23

as 50% agreement was given to both samples.

32

4.6.1.3 Single Polyester

Control 7: Rank 3 – 90% Sample 10: Rank 2 – 50% Sample 12: Rank 1 – 50%

Figure 19: Control 7 Abrasion Figure 20: Sample 10 Abrasion Figure 21: Sample 12 Abrasion All of the samples when abraded, formed pills on the fabric surface. The pilling is

contributed to the stronger polyester fibers not breaking away from the fabric surface.

However, as specific energy increases, the number and size of pills decrease as

indicated in Figure 21. This suggests higher energy is required to further entangle the

surface fibers into the fabric structure. When visually ranked, there was only 50%

agreement that sample 12 is the best abrasive resistant sample. This suggests that

since there is little visible difference that the lower energy sample, or sample 10 is

sufficient.

33

4.6.1.4 Double Polyester

Control 24: Rank 3 – 100% Sample 26: Rank 2 – 90% Sample 28: Rank 1 – 90%

Figure 22: Control 24 Abrasion Figure 23: Sample 26 Abrasion Figure 24: Sample 28 Abrasion

The double polyester samples performed in a similar manner to the single polyester

samples in that the number and size of pills decreased as energy increased. When

visually ranked, there was a clear agreement that not hydroentangling (Control 24) is

the worst sample and there was 90% agreement that the high energy sample (sample

28) proved to have the best abrasion resistance performance. Sample 28 received the

highest level of specific energy (5486 KJ/Kg) at a speed of 10 meters per minute,

pressure of 220 Bar, and 3 passes. Sample 26 was processed with very similar

process parameters. Sample 26 was processed at medium specific energy (3292

KJ/Kg) or at 50 meters per minute, 220 Bars of pressure, and 3 passes. The only

processing difference between sample 26 and sample 28 is the speed, which suggests

that the slower speed is necessary to allow the fibers ample time to further entangle into

the fabric surface.

34

4.6.1.5 Single Blend

Control 13: Rank 3 – 90% Sample 15: Rank 2 – 80% Sample 27: Rank 1 – 80%

Figure 25: Control 13 Abrasion Figure 26: Sample 15 Abrasion Figure 27: Sample 16 Abrasion The single blend samples require a high level of energy (21,361 KJ/Kg) to achieve

desirable abrasion resistance results. The high level of energy is contributed to the

presence of the stronger polyester fibers. In order to achieve higher abrasion

resistance, 220 bar of pressure and a speed of 10 meters per minute are necessary.

There is a clear indication from the rankings that hydroentangling does improve

abrasion resistance, as there was a 90% agreement that the control sample showed

significant pilling when abraded as Figure 25 indicates.

35

4.6.1.6 Double Blend

Control 29: Rank 3 – 100% Sample 31: Rank 2 – 80% Sample 33: Rank 1 – 90% Figure 28: Control 29 Abrasion Figure 29: Sample 31 Abrasion Figure 30: Sample 33 Abrasion The double blend samples require a high level of energy (10,681 KJ/Kg) to achieve

desirable abrasion resistance results just as the single blend samples. The high level of

energy is contributed to the presence of the stronger polyester fibers. In order to

achieve higher abrasion resistance, 220 bar of pressure and a speed of 10 meters per

minute are necessary. There is a clear indication from the rankings that

hydroentangling does improve abrasion resistance, as there was a 100% agreement

that the control sample showed significant pilling when abraded as Figure 28 indicates.

Sample 33, hydroentangled at the highest level of specific energy proved to have the

best abrasion resistance.

36

4.6.1.7 Abrasion Resistance Discussion For each of the six fabric types, the best sample with respect to abrasion resistance is

displayed in Table 4 along with the performance parameters of each sample. Ignoring

other performance parameters such as pilling resistance, the process parameters can

be optimized to achieve the greatest abrasion resistance results. For all of the samples,

it is clear that 10 meters per minute achieves better results than a speed setting of 50

meters per minute. The level of pressure and the number of passes however vary

between the samples. Each of the double knit samples (samples 33, 22, and 28)

require pressure of 220 Bar. The single knit samples require 100 Bar of pressure. It is

noted that the best abrasion result for the single cotton sample (sample 6) was

hydroentangled at 220 Bar. However, the fibers were significantly damaged as

discussed in the Scanning Electron Micrograph section of this report. Hydroentangling

the single cotton at the lower pressure level of 100 Bar achieves satisfactory results.

BEST ABRASION

SAMPLE FIBER TYPEKNIT

CONSTRUCTIONSPEED M/MIN

PRESSURE BAR

NUMBER OF

PASSESENERGY

KJ/KG16 BLEND SINGLE 10 100 3 1009633 BLEND DOUBLE 10 220 2 106816 COTTON SINGLE 10 220 3 2274022 COTTON DOUBLE 10 220 1 429812 POLY SINGLE 10 100 2 3228728 POLY DOUBLE 10 220 3 5486

Table 4: Best Abrasion Resistant Samples

4.6.2 Pilling Resistance All 33 samples were evaluated for pilling resistance. The samples for each fabric type

were evaluated according to ASTM standards and the control fabric was compared

optically to the best overall sample. All of the samples showed improvement over the

control sample in regard to pilling resistance.

37

4.6.2.1 Single Cotton

Figure 31: Control 1 Pilling Figure 32: Sample 3 Pilling

SAMPLEASTM

RATINGOPTICAL RATING

SPECIFIC ENERGY

KJ/KG1 1.0 209 02 4.5 130 4783 5.0 109 9554 5.0 81 45485 5.0 54 75806 5.0 97 22740

Table 5: Cotton Single Pill Rating

Control sample 1 displays failing results with respect to pilling resistance as indicated

optically in Figure 31, and in ASTM and optical rankings. Hydroentangling does

improve pilling resistance significantly. As indicated in Table 5, each of the samples

was rated at the various levels. A relatively low amount of energy is required to achieve

optimum pilling resistance results as indicated by sample 3. Hydroentangling beyond

955 KJ/Kg is unnecessary as peak performance occurs at this level. Samples 2 and 3

were both hydroentangled at 50 meters per minute and 100 Bar. The difference is

sample 2 was processed at 1 pass and sample 3 was processed at 2 passes.

38

4.6.2.2 Double Cotton

Figure 33: Control 18 Pilling Figure 34: Sample 20 Pilling

SAMPLEASTM

RATINGOPTICAL RATING

SPECIFIC ENERGY

KJ/KG18 3.0 170 019 4.0 52 27120 5.0 54 81321 4.0 68 135422 5.0 41 429823 5.0 62 8597 Table 6: Cotton Double Pilling Rating

The double cotton samples achieved similar results to the single cotton samples.

Control sample 18 displays the worst performance with respect to pilling resistance as

indicated optically in Figure 33, and in ASTM and optical rankings. Hydroentangling

does improve pilling resistance significantly. As indicated in Table 6, each of the

samples was rated at the various energy levels. A relatively low amount of energy is

required to achieve optimum pilling resistance results as indicated by sample 20.

Hydroentangling beyond 813 KJ/Kg is unnecessary as peek performance occurs at this

level. Samples 19 and 20 were both hydroentangled at 50 meters per minute and 220

Bar. The difference is sample 19 was processed at 1 pass and sample 20 was

processed at 3 passes.

39

4.6.2.3 Single Polyester

Figure 35: Control 7 Pilling Figure 36: Sample 10 Pilling

SAMPLE ASTM

RATINGOPTICAL RATING

SPECIFIC ENERGY

KJ/KG 7 1.0 165 0 8 1.0 169 678 9 3.0 137 3391 10 4.0 130 4305 11 3.5 133 10762 12 1.0 167 32287

Table 7: Single Polyester Pilling Rating

Polyester responds differently to hydroentangling with respect to pilling resistance than

cotton does. Single knit polyester reaches a peak in pilling performance at 4305 KJ/Kg

(sample 10) and deteriorates to failing performance at extreme levels of energy. At low

energy levels (sample 8) and no hydroentangling (Control 7), the surface fibers

protruding from the fabric are free to form pills easily. Hydroentangling polyester at

extremely high energy (sample 12, 32287 KJ/Kg) causes the fabric to fuzz and also

makes the surface fibers available to hold pills to the fabric surface. This indicates that

the fabric must be hydroentangled at a specific level of energy to entangle the available

surface fibers into the fabric surface (sample 10).

40

4.6.2.4 Double Polyester

Figure 37: Control 24 Pilling Figure 38: Sample 27 Pilling

SAMPLE ASTM

RATINGOPTICAL RATING

SPECIFIC ENERGY

KJ/KG 24 1.5 204 0 25 1.0 270 1097 26 2.5 226 3292 27 4.5 181 3457 28 4.5 123 5486

Table 8: Double Polyester Pilling Rating

The double knit structure in itself reduces the tendency of the fabric to pill. However, as

the ASTM a ratings indicate, hydroentangling further increases pilling resistance, and as

the intensity of energy increases pilling resistance improves.

41

4.6.2.5 Single Blend

Figure 39: Control 13 Pilling Figure 40: Sample 17 Pilling

SAMPLE ASTM

RATINGOPTICAL RATING

SPECIFIC ENERGY

KJ/KG 13 1.0 398 0 14 4.0 310 2019 15 4.0 251 2136 16 4.5 227 10096 17 5.0 131 21361

Table 9: Single Blend Pilling Rating

To achieve an ASTM rating of 5.0, single blend fabrics should be hydroentangled at a

high energy level. The control fabric (Control 13) received a failing rating of 1.0

indicating that any level of hydroentangling improves pilling resistance.

42

4.6.2.6 Double Blend

Figure 41: Control 29 Pilling Figure 42: Sample 33 Pilling

SAMPLE ASTM

RATINGOPTICAL RATING

SPECIFIC ENERGY

KJ/KG 29 1.0 226 0 30 2.5 185 1068 31 2.0 205 5048 32 4.0 137 5340 33 4.5 111 10681

Table 10: Double Blend Pilling Rating Like the single blend fabrics, the double knit construction also requires a high level of

energy (sample 33, 10681 KJ/Kg) to increase pilling resistance. The control sample

(sample 29) pilled significantly. As is the case with all of the fabric types,

hydroentangling increases pilling resistance.

43

4.6.3 Scanning Electron Micrographs Micrographs were taken of the cotton and polyester fabrics at 50, 100, and 200

magnifications to determine fiber damage. None of the polyester fabrics appeared to

show fiber damage at any level of energy. The cotton samples however did show signs

of fiber damage as a result of hydroentanglement.

4.6.3.1 Single Cotton Figure 43 is a micrograph of the control fabric for the single knit cotton fabrics. The

micrograph shows that there is minimal fiber damage. Figure 44, however shows

significant fiber damage as a result of hydroentangling. Samples 4, 5, 6 were

hydroentangled at a pressure of 220 Bar and each of the fabric samples displayed fiber

damage. Hydroentangling at 100 Bar greatly reduces fiber damage while still optimizing

pilling resistance and abrasion resistance.

Figure 43: Micrograph Control 1 Figure 44: Micrograph Sample 6

44

4.6.3.2 Double Cotton Like the single knit samples, the double knit samples also display fiber damage as a

result of high pressure (220 Bar). However, the damage is not as pronounced in the

double knit construction as it is in the single knit samples. The double knit construction

allows for better protection of the fibers.

Figure 45: Micrograph Control 18 Figure 46: Micrograph Sample 23

4.6.3.3 Single Polyester The increased strength of the polyester protects the fibers from any damage as a result

of high pressure. High pressures can be used to achieve optimum performance

parameters without causing any fiber damage.

Figure 47: Micrograph Control 7

Figure 48: Micrograph Sample 12

45

4.6.3.4 Double Polyester The polyester fibers do not incur any damage as a result of hydroentangling, but the

fibers are rearranged, giving greater surface coverage.

Figure 49: Micrograph Control 24 Figure 50: Micrograph Sample 28

4.6.4 Weight Knitted fabrics naturally tend to resort to a relaxed state as a result of wetting the fabric.

The hydroentangling process causes the fabric to shrink and then be stabilized due to

surface fibers being further entangled into the fabric structure. Holding the fabric in a

fixed position could reduce shrinkage during the hydroentangling process. For this

experiment however, the fabric was allowed to contract as it was passed under the jets.

As a result, the fabric weight increases because there are more fibers in the same area.

Fabric construction and fiber type do play an integral role in the change in weight or

fabric constriction. Cotton and single knits will incur a greater change than would

polyester and double knits.

46

4.6.4.1 Single Cotton Given the nature of knits, it could be assumed that all of the cotton samples would

increase in weight as energy increases. However, this is not the case. Samples 2 and

3 increased in weight compared to control 1. Samples 2 and 3 were both processed at

50 meters per minute, 100 Bar of pressure, and one and two passes respectively. The

remaining samples were processed at 220 Bar of pressure and 10 meters per minute;

those samples decreased in weight compared to the control. The slight decrease in

fabric weight could be contributed to fibers being washed away. This is also made

evident in the amount of fiber collected by the filtration system.

SPECIFIC ENERGY (KJ/KG)0 5000 10000 15000 20000 25000

WEI

GH

T (G

SM)

160

170

180

190

200

210

Figure 51: Single Cotton Weight

SAMPLE CONSTRUCTIONFIBER TYPE

AVG WEIGHT (GSM) ST DEV

SPEED (M/MIN)

PRESSURE (BAR) PASSES

SPECIFIC ENERGY (KJ/KG)

1 SINGLE COTTON 186.4 3 0 0 0 02 SINGLE COTTON 200.8 4 50 100 1 4783 SINGLE COTTON 197.0 6 50 100 2 9554 SINGLE COTTON 183.8 4 50 220 3 45485 SINGLE COTTON 179.5 3 10 220 1 75806 SINGLE COTTON 173.0 6 10 220 3 22740

Table 11: Fabric Weight Single Cotton

47

4.6.4.2 Double Cotton Hydroentangling caused an increase in weight for all of the double cotton samples.

Pressure of 220 Bar caused a greater fabric contraction than the samples processed at

100 Bar. Sample 20 was processed for 3 passes and as Figure 52 indicates, the

sample did not have as much weight gain as the other samples. This may be due to

some fibers being washed away with the increase in passes.

SPECIFIC ENERGY (KJ/KG)0 2000 4000 6000 8000 10000

WEI

GH

T (G

SM)

300

320

340

360

380

400

420

Figure 52: Double Cotton Weight

SAMPLE CONSTRUCTIONFIBER TYPE

AVG WEIGHT (GSM) ST DEV

SPEED (M/MIN)

PRESSURE (BAR) PASSES

SPECIFIC ENERGY (KJ/KG)

18 DOUBLE COTTON 327.5 4 0 0 0 019 DOUBLE COTTON 383.9 5 50 100 1 27120 DOUBLE COTTON 392.3 3 50 100 3 81321 DOUBLE COTTON 359.8 10 10 100 1 135422 DOUBLE COTTON 408.6 3 10 220 1 429823 DOUBLE COTTON 398.0 3 10 220 2 8597

Table 12: Fabric Weight Double Cotton

48

4.6.4.3 Single Polyester Two trends are made evident as shown in Figure 53. Two samples were processed at

50 meters per minute and the remaining samples were processed at 10 meters per

minute. Samples 8 and 10 vary by pressure at the same high speed setting. The

higher pressure caused a greater increase in weight, which may suggest that higher

pressure causes more shrinkage.

Figure 53: Single Polyester Weight

SAMPLE CONSTRUCTIONFIBER TYPE

AVG WEIGHT (GSM) ST DEV

SPEED (M/MIN)

PRESSURE (BAR) PASSES

SPECIFIC ENERGY (KJ/KG)

7 SINGLE POLY 131.4 14 0 0 0 08 SINGLE POLY 169.7 4 50 100 1 6789 SINGLE POLY 157.6 3 10 100 1 3391

10 SINGLE POLY 190.4 2 50 220 1 430511 SINGLE POLY 170.6 2 10 220 1 1076212 SINGLE POLY 193.9 5 10 100 2 32287

Table 13: Fabric Weight Poly Single

49

4.6.4.4 Double Polyester Like the single knit polyester samples, two trends are also evident in the polyester

double samples. Two samples were processed at high speed and two at low speed. At

the high and low speed settings, the increase in pressure causes an increased fabric

weight.

Figure 54: Double Polyester Weight

SAMPLE CONSTRUCTIONFIBER TYPE

AVG WEIGHT (GSM) ST DEV

SPEED (M/MIN)

PRESSURE (BAR) PASSES

SPECIFIC ENERGY (KJ/KG)

24 DOUBLE POLY 257.4 5 0 0 0 025 DOUBLE POLY 333.5 2 50 220 1 109726 DOUBLE POLY 343.5 4 50 220 3 329227 DOUBLE POLY 329.7 3 10 100 2 345728 DOUBLE POLY 349.4 9 10 220 3 5486

Table 14: Fabric Weight Poly Double

50

4.6.4.5 Single Blend Samples 14 and 15 were hydroentangled at 2019 and 2136 KJ/Kg respectively. Both

samples were processed at high speed, but the pressure and the number of passes

varied, creating different results despite the almost equal amount of energy. In this

case, sample 15 was processed at higher pressure which would suggest that the weight

would be higher, however the weight is lower. This may be attributed to the interaction

of the cotton and the number of passes. The combination of processing the fabric at

high pressure and 3 passes washes away some of the cotton, causing the fabric to not

shrink as much and therefore not increase in weight as much.

Figure 55: Single Blend Weight

SAMPLE CONSTRUCTIONFIBER TYPE

AVG WEIGHT (GSM) ST DEV

SPEED (M/MIN)

PRESSURE (BAR) PASSES

SPECIFIC ENERGY (KJ/KG)

13 SINGLE BLEND 131.5 3 0 0 0 014 SINGLE BLEND 161.4 2 50 100 3 201915 SINGLE BLEND 147.8 1 50 220 1 213616 SINGLE BLEND 154.7 7 10 100 3 1009617 SINGLE BLEND 157.3 2 10 220 2 21361

Table 15: Fabric Weight Blend Single

51

4.6.4.6 Double Blend Sample 31 and 32 were hydroentangled at similar specific energy, 5048 and 5340

KJ/Kg respectively. Despite the similar specific energy, the samples reacted differently.

Although sample 32 was processed at higher pressure, sample 31 was processed for 3

passes. The number of passes does increase the fabric weight by causing greater

fabric shrinkage.

Figure 56: Double Blend Weight

SAMPLE CONSTRUCTIONFIBER TYPE

AVG WEIGHT (GSM) ST DEV

SPEED (M/MIN)

PRESSURE (BAR) PASSES

SPECIFIC ENERGY (KJ/KG)

29 DOUBLE BLEND 264.1 2 0 0 0 030 DOUBLE BLEND 291.4 4 50 220 1 106831 DOUBLE BLEND 304.5 9 10 100 3 504832 DOUBLE BLEND 289.8 7 10 220 1 534033 DOUBLE BLEND 297.5 4 10 220 2 10681

Table 16: Fabric Weight Blend Double

52

4.6.5 Air Permeability and Water Vapor Transmission Rate (WVTR) 4.6.5.1 Single Cotton There is a loss of air permeability as a result of hydroentangling. However, once

hydroentangled at any energy level, air permeability does not continue to decrease, but

remains relatively constant. The loss of air permeance is attributed to the tightened

fabric structure. Hydroentangling creates more bonding points and reduces air flow in

the process. Water vapor transmission rate increases as a result of hydroentangling.

SPECIFIC ENERGY (KJ/KG)0 5000 10000 15000 20000 25000

AIR

PER

MEA

BIL

ITY

(CFM

)

100

150

200

250

300

350

400AIR PERMEABILITY VS SPECIFIC ENERGY

WVT

R (G

/(M2 D

AY)

10000

15000

20000

25000

30000

35000

40000

45000WVTR VS SPECIFIC ENERGY

Figure 57: Single Cotton Air Permeability and WVTR

4.6.5.2 Double Cotton As with the single knit cotton samples, the double knit cotton also show an initial

decrease in air permeability. The loss is constant as energy increases. Water vapor

transmission rate greatly decreases as energy increases, but the fabric is still moisture

permeable.

53

SPECIFIC ENERGY (KJ/KG)0 2000 4000 6000 8000 10000

AIR

PER

MEA

BIL

ITY

(CFM

)

0

50

100

150

200AIR PERMEABILITY VS SPECIFIC ENERGY

WVT

R (G

/(M2 D

AY)

020004000600080001000012000140001600018000

WVTR VS SPECIFIC ENERGY

Figure 58: Double Cotton Air Permeability and WVTR

4.6.5.3 Single Polyester The air permeability loss is not as pronounced as the cotton samples. In this instance,

there is an initial 34% loss at low energy and on ultimate loss of 65% at high energy.

Air permeability continues to decrease as specific energy is increased. There is a great

loss of water vapor transmission rate however, since the control sample tested at such

a high level, 19215 grams per square meter day is still a very high and acceptable level

of water vapor transmission rate.

54

WVT

R (G

/(M2 D

AY)

15000

20000

25000

30000

35000

40000

45000

50000

55000

WVTR VS SPECIFIC ENERGY

SPECIFIC ENERGY (KJ/KG)0 5000 10000 15000 20000 25000 30000 35000

AIR

PER

MEA

BIL

ITY

(PSI

)

100

200

300

400

500

600AIR PERMEABILITY VS SPECIFIC ENERGY

Figure 59: Single Polyester Air Permeability and WVTR

4.6.5.4 Double Polyester Unlike the single knit polyester samples, the double polyester samples increased in

water vapor transmission rate. Looking at air permeability, these samples have an

almost linear rate as specific energy increases. There is an ultimate air permeability

loss of 78%, however, the fabric is still breathable. The greater air permeability loss

over the single polyester samples is attributed to the tightened fabric structure and

increased surface area.

55

SPECIFIC ENERGY (KJ/KG)0 1000 2000 3000 4000 5000 6000

AIR

PER

MEA

BIL

ITY

(CFM

)

0

100

200

300

400AIR PERMEABILITY VS SPECIFIC ENERGY

WVT

R (G

/(M2 D

AY)

6000

8000

10000

12000

14000

16000

18000

20000

22000

WVTR VS SPECIFIC ENERGY

Figure 60: Double Polyester Air Permeability and WVTR

4.6.5.5 Single Blend There is no significant statistical difference in water vapor transmission rate between the

control sample and the high energy sample. There is ultimately a 56% loss in air

permeability compared to the control sample. While the loss is significant, the fabric still

performs at a comfortable level. Air permeability also remains relatively constant as

specific energy increases.

56

WVT

R (G

/(M2 D

AY)

10000

15000

20000

25000

30000

35000

40000WVTR VS SPECIFIC ENERGY

SPECIFIC ENERGY (KJ/KG)0 5000 10000 15000 20000 25000

AIR

PER

MEA

BIL

ITY

(CFM

)

200

300

400

500

600

700AIR PERMEABILITY VS SPECIFIC ENERGY

Figure 61: Single Blend Air Permeability and WVTR

4.6.5.6 Double Blend Like the single blend samples, there is an initial loss in air permeability as a result of

hydroentangling and the loss remains constant as specific energy increases. There

was also a loss in water vapor transmission rates. Even at the highest energy level, the

samples still perform at a comfortable air permeability and water vapor transmission

rate.

SPECIFIC ENERGY (KJ/KG)0 2000 4000 6000 8000 10000 12000

AIR

PER

MEA

BIL

ITY

(CFM

)

0

50

100

150

200

250

300AIR PERMEABILITY VS SPECIFIC ENERGY

WVT

R (G

/(M2 D

AY)

10000

15000

20000

25000

30000

35000

40000

45000

50000

WVTR VS SPECIFIC ENERGY

Figure 62: Double Blend Air Permeability and WVTR

57

4.6.6 Stiffness (Length of Overhang in Machine and Cross Direction) Stiffness was tested using the cantilever method by characterizing the length of

overhang in the machine and cross directions. The higher the length of overhang, the

stiffer the fabric is. In some cases, the length of overhang could not be measured due

to the natural curling tendencies of the fabric. In those cases, the fabric is considered to

be not stiff because could the fabric be tested, the results would have a very low length

of overhang. In general, length of overhang of 4 cm or less for the single knit samples

is considered ideal and 7 cm or less for the double knit samples.

4.6.6.1 Single Cotton It is known that cotton fabrics become stiffer when hydroentangled. This is true to a

certain level. For this fabric, the control fabric could not be tested due to excessive

curling, but the control is considered to not be stiff. The first two samples shown in

Figure 63 at less than 1000 kilojoules per kilogram, have an acceptable and comfortable

level of stiffness. Both of those samples were hydroentangled at 100 Bar. The

remaining samples were hydroentangled at 220 Bar. This suggest that hydroentangling

at the high pressure setting causes the fabric to become too stiff and single cotton

should be hydroentangled at lower pressure settings. As discussed throughout this

report, a low level of specific energy still achieves desirable performance results.

58

SPECIFIC ENERGY (KJ/KG)0 5000 10000 15000 20000 25000

OVE

RH

AN

G L

ENG

TH (C

M)

0

1

2

3

4

5

6OVERHANG LENGTH MD VS SPECIFIC ENERGYOVERHANG LENGTH CD VS SPECIFIC ENERGY

Figure 63: Single Cotton Length of Overhang

4.6.6.2 Double Cotton For the double cotton samples, stiffness does increase as a result of hydroentangling.

But once hydroentangled, the length of overhang is relatively constant as specific

energy increases. This suggests, if 6 cm of overhang length is acceptable, then a high

level of energy can be used to optimize other performance parameters.

59

SPECIFIC ENERGY (KJ/KG)0 2000 4000 6000 8000 10000

OVE

RH

AN

G L

ENG

TH (C

M)

2

4

6

8

10OVERHANG LENGTH MD VS SPECIFIC ENERGYOVERHANG LENGTH CD VS SPECIFIC ENERGY

Figure 64: Cotton Double Length of Overhang

4.6.6.3 Single Polyester Not all of the samples could be tested due to excessive curling of the fabric. From the

samples that could be tested, stiffness increases as specific energy increases. It should

be noted that all of the samples are below 4 cm and are considered to not be stiff.

60

SPECIFIC ENERGY (KJ/KG)0 2000 4000 6000 8000 10000 12000

OVE

RH

AN

G L

ENG

TH (C

M)

1.0

1.5

2.0

2.5

3.0

3.5

4.0OVERHANG LENGTH MD VS SPECIFIC ENERGYOVERHANG LENGTH CD VS SPECIFIC ENERGY

Figure 65: Single Polyester Length of Overhang

4.6.6.4 Double Polyester All of the double polyester samples are not considered to be stiff. Stiffness does

increase as a result of hydroentangling but the overhang length is relatively constant as

specific energy increases.

61

SPECIFIC ENERGY (KJ/KG)0 1000 2000 3000 4000 5000 6000

OVE

RH

AN

G L

ENG

TH (C

M)

0

2

4

6

8

10OVERHANG LENGTH MD VS SPECIFIC ENERGYOVERHANG LENGTH CD VS SPECIFIC ENERGY

Figure 66: Polyester Double Length of Overhang

4.6.6.5 Single Blend Due to excessive fabric curling in the single blend samples, only one sample could be

tested. It is assumed however that all of the samples are flexible.

62

SPECIFIC ENERGY (KJ/KG)0 5000 10000 15000 20000 25000

OVE

RH

AN

G L

ENG

TH (C

M)

0

2

4

6OVERHANG LENGTH MD VS SPECIFIC ENERGYOVERHANG LENGTH CD VS SPECIFIC ENERGY

Figure 67: Blend Single Length of Overhang

4.6.6.6 Double Blend Stiffness does increase as a result of hydroentangling when compared to the control.

The length of overhang, once hydroentangled is relatively constant as specific energy

increases. All of the samples are considered to be within acceptable limits of flexibility.

63

SPECIFIC ENERGY (KJ/KG)0 2000 4000 6000 8000 10000 12000

OVE

RH

AN

G L

ENG

TH (C

M)

0

2

4

6

8

10OVERHANG LENGTH MD VS SPECIFIC ENERGYOVERHANG LENGTH CD VS SPECIFIC ENERGY

Figure 68: Double Blend Length of Overhang

4.6.7 Thickness The fabric was allowed to move freely during hydroentangling. Thus it was

hypothesized that as the fabric shrinks as a result of hydroentangling that the fabric

thickness would also increase. To test the hypothesis, fabric thickness and fabric

weight are plotted together.

4.6.7.1 Single Cotton Fabric thickness follows the same trend as fabric weight except at the high energy level.

At 22,740 kilojoules per kilogram, thickness is lower than the weight, which is the

opposite reaction from the remaining samples. Also, thickness does initially increase at

low energy and at high energy, but at medium energy, there is no difference.

64

THIC

KN

ESS

(MM

)

0.460.480.500.520.540.560.580.600.620.640.66

THICKNESS VS SPECIFIC ENERGY

SPECIFIC ENERGY (KJ/KG)0 5000 10000 15000 20000 25000

WEI

GH

T (G

SM)

160

170

180

190

200

210

WEIGHT VS SPECIFIC ENERGY

Figure 69: Single Cotton Thickness

4.6.7.2 Double Cotton As is the case with the single cotton samples, the double cotton samples also follow the

same pattern in that fabric thickness follows the same trend as fabric weight. The fabric

weight overall is increasing.

SPECIFIC ENERGY (KJ/KG)0 2000 4000 6000 8000 10000

THIC

KN

ESS

(MM

)

0.75

0.80

0.85

0.90

0.95

1.00

1.05

1.10

THICKNESS VS SPECIFIC ENERGY

WEI

GH

T (G

SM)

300

320

340

360

380

400

420

WEIGHT VS SPECIFIC ENERGY

Figure 70: Double Cotton Thickness

65

4.6.7.3 Single Polyester Fabric thickness increases as specific energy and fabric weight increase.

SPECIFIC ENERGY (KJ/KG)0 5000 100001500020000250003000035000

THIC

KN

ESS

(MM

)

0.35

0.40

0.45

0.50

0.55

0.60

0.65

THICKNESS VS SPECIFIC ENERGY

WEI

GH

T (G

SM)

100

120

140

160

180

200

220

WEIGHT VS SPECIFIC ENERGY

Figure 71: Single Polyester Thickness

4.6.7.4 Double Polyester

SPECIFIC ENERGY (KJ/KG)0 1000 2000 3000 4000 5000 6000

THIC

KN

ESS

(MM

)

0.5

0.6

0.7

0.8

0.9

1.0

THICKNESS VS SPECIFIC ENERGY

SPECIFIC ENERGY (KJ/KG)0 1000 2000 3000 4000 5000 6000

WEI

GH

T (G

SM)

240

260

280

300

320

340

360

380

WEIGHT VS SPECIFIC ENERGY

Figure 72: Double Polyester Thickness

66

4.6.7.5 Single Blend

THIC

KN

ESS

(MM

)

0.30

0.35

0.40

0.45

0.50

0.55

0.60

THICKNESS VS SPECIFIC ENERGY

SPECIFIC ENERGY (KJ/KG)0 5000 10000 15000 20000 25000

WEI

GH

T (G

SM)

125

130

135

140

145

150

155

160

165

WEIGHT VS THICKNESS

Figure 73: Single Blend Thickness

4.6.7.6 Double Blend

SPECIFIC ENERGY (KJ/KG)-2000 0 2000 4000 6000 8000 10000

THIC

KN

ESS

(MM

)

0.5

0.6

0.7

0.8

0.9

1.0

1.1

THICKNESS VS SPECIFIC ENERGY

WEI

GH

T (G

SM)

240

260

280

300

320

340

360

380

400

420

WEIGHT VS SPECIFIC ENERGY

Figure 74: Double Blend Thickness

67

4.6.8 Consumer Wash Shrinkage Samples were evaluated for shrinkage using consumer laundering procedures. Since it

is already known that knitted fabrics have a tendency to shrink when introduced to

water, the control sample was evaluated after being laundering once. Hydroentangling

does decrease the severity of shrinkage because the fabric structure is altered. During

hydroentangling, the surface fibers are locked into the structure and stabilized,

preventing further fiber movement. Ideally, shrinkage is inherent, but needs to be

minimized whenever possible. In the following sections describing wash shrinkage as a

function of specific energy, it is desirable for the data to fall near zero in the machine

and cross directions. A positive value indicates that the fabric stretched, and as to be

expected, the majority of shrinkage occurred in the machine direction.

4.6.8.1 Single Cotton For the single cotton samples, the control fabric had the greatest amount of shrinkage at

26.0% in the machine direction. On average, the hydroentangled samples shrunk 9.8

%. As Figure 75 indicates, shrinkage does not increase significantly as specific energy

is increased. Pressure and speed also do not appear to be significant factors in the

severity of shrinkage.

SPECIFIC ENERGY (KJ/KG)0 5000 10000 15000 20000 25000

CO

NSU

MER

WA

SH S

HR

INK

AG

E (%

)

-20

-10

0

10

20

30WASH SHRINKAGE MD vs SPECIFIC ENERGYWASH SHRINKAGE CD vs SPECIFIC ENERGY

Figure 75: Single Cotton Wash Shrinkage

68

4.6.8.2 Double Cotton The control sample had the greatest shrinkage at 14.1% in the machine direction while

the remaining samples shrunk 1.2% on average. As to be expected, shrinkage is less

in the double knit structure than the single knit structure. The samples hydroentangled

at high pressure (4298 and 8597 KJ/Kg) have the most stable fabric structure, however

there is no change as specific energy is increased. This suggests that no amount of

hydroentangling will ever completely alleviate shrinkage.

S P E C IF IC E N E R G Y (K J /K G )0 2 0 0 0 4 0 0 0 6 0 0 0 8 0 0 0 1 0 0 0 0

CO

NSU

MER

WA

SH S

HR

INK

AG

E (%

)

-2 0

-1 0

0

1 0

2 0

3 0

4 0W A S H S H R IN K A G E M D v s S P E C IF IC E N E R G YW A S H S H R IN K A G E C D v s S P E C IF IC E N E R G Y

Figure 76: Double Cotton Wash Shrinkage

4.6.8.3 Single Polyester The control sample shrunk 15.7% in the machine direction while the hydroentangled

samples shrunk 2.5% on average. Shrinkage is minimized as a result of

hydroentangling and the hydrophobic nature of polyester. It is noted that as specific

energy increases, shrinkage is relatively unchanging.

69

SPECIFIC ENERG Y (K J/KG )0 5000 10000 15000 20000 25000 30000 35000

CO

NSU

MER

WA

SH S

HR

INK

AG

E (%

)

-10

-5

0

5

10

15

20W AS H S H R IN KA G E M D vs S PE C IFIC EN E R G YW AS H S H R IN KA G E C D vs S PE C IFIC EN E R G Y

Figure 77: Single Polyester Wash Shrinkage

4.6.8.4 Double Polyester The double polyester samples had similar results to the single polyester samples. The

control fabric shrunk 14.7% in the machine direction and the hydroentangled samples

shrunk 3.2% on average. For the hydroentangled samples, the degree of shrinkage is

directly proportional to the degree of stretch in the cross direction. This suggests that

the experience movement, but shrinkage does not occur. Hydroentangling does

minimize shrinkage but the results are constant as specific energy is increased.

S P E C IF IC E N E R G Y (K J /K G )0 1 0 0 0 2 0 0 0 3 0 0 0 4 0 0 0 5 0 0 0 6 0 0 0

CO

NSU

MER

WA

SH S

HR

INK

AG

E (%

)

-1 0

-5

0

5

1 0

1 5

2 0W A S H S H R IN K A G E M D v s S P E C IF IC E N E R G YW A S H S H R IN K A G E C D v s S P E C IF IC E N E R G Y

Figure 78: Double Polyester Wash Shrinkage

70

4.6.8.5 Double Blend The control fabric had the greatest amount of shrinkage in the machine direction at

18.9%. The hydroentangled samples on average shrunk 5.2% in the machine direction.

This fabric, with regard to shrinkage performed more like a cotton fabric rather than a

polyester fabric. Hydroentangling does minimize fabric shrinkage, but like the other

fabric types, is constant as specific energy increases.

S P E C IF IC E N E R G Y (K J /K G )0 2 0 0 0 4 0 0 0 6 0 0 0 8 0 0 0 1 0 0 0 0 1 2 0 0 0

CO

NSU

MER

WA

SH S

HR

INK

AG

E (%

)

- 1 0

0

1 0

2 0W A S H S H R IN K A G E M D v s S P E C IF IC E N E R G YW A S H S H R IN K A G E C D v s S P E C IF IC E N E R G Y

Figure 79: Double Blend Wash Shrinkage

5 Conclusions Overall, all of the hydroentangled fabric types displayed improvement with respect to

pilling resistance, abrasion resistance, shrinkage and dimensional stability. These

optimizations are realized at various levels of specific energy and air permeability and

water vapor transmission rates are compromised as a result. In all hydroentangled

samples, fabric weight and thickness were found to be related and increased over the

original control samples.

For each fabric type, a certain level of specific energy must be achieved to optimize

performance parameters. The blend samples require the highest level of energy or

21,000 and 10,000 KJ/Kg for the single and double knit constructions respectively. This

level of energy is required to entangle the fibers into the fabric surface to the point that

the fibers are not protruding from the surface and available to form pills. Of the three

71

fabric types tested (cotton, polyester, and a cotton polyester blend) the blend would be

most likely to pill.

The cotton samples require the lowest amount of specific energy to achieve desired

results (1000 and 800 KJ/Kg for single and double knit constructions respectively). A

low amount of energy is needed because cotton fabrics are the least likely to form pills.

Cotton fibers are inherently weak and are thus not prone to pill as much as synthetic

fibers. Hydroentangling cotton fabrics at high energy, or greater than 5000 KJ/Kg

damages the fibers causing the fabric to become stiffer and weaker.

The polyester fabrics require a medium level of specific energy (4300 and 3500 KJ/Kg

for single knit and double knit constructions respectively). Polyester has a greater

tendency to pill than cotton fabrics do because polyester fibers are stronger. Polyester

has a tendency to fuzz when hydroentangled. A delicate balance between causing the

fabric to fuzz and become rough is ideal. Hydroentangling polyester at extremely high

levels of energy (20,000 KJ/Kg) is unnecessary and the high pressure needed to

achieve high levels of energy causes the fabric to bond to the belt. This phenomena

occurs in polyester fabrics because the fibers are stronger and harder to break away

from the fabric surface.

A certain level of air permeability is lost due to hydroentangling because the fabric

structure is bonded and closed more than the control samples. The control samples

have a very open structure and the yarns remain in columns. Micrographs suggest that

hydroentanglement rearranges individual fibers giving the fabric greater surface area.

This closed structure restricts air flow and thus decreases air permeability to an extent.

Once hydroentangled however, air permeability is constant as specific energy is

increased. If the initial loss in air permeability is acceptable, then high levels of energy

can be obtained without incurring further losses.

72

6 Recommendations and Future Work Currently a method does not exist to stabilize the fabric through the hydroentangling

equipment. The fabric is free to move and fabric stability can not be controlled. Single

knit fabrics in particular tend to curl towards the center of the fabric structure. A great

amount of tension can not be placed on the fabric to hold it steady because the knit

would have to be stretched to the point the selvages would no longer be uniform. An

attempt was made to sew a heavy seam along the fabric selvages to prevent curling,

but this method was insufficient. Curling is a serious problem in the hydroentangling

process because the as the fabric curls in, the pressure entangles fibers creating bonds

that make the curl semi-permanent. The fabric continues to curl further as the fabric is

passes through subsequent jets. The more manifolds the fabric is passed under, the

greater the fabric curls. Method needs to be developed to stabilize the fabric selvages.

A standard jet strip was used to hydroentangle the knitted fabrics. Since

hydroentangling equipment is not traditionally used to process knits, some investigation

needs to be conducted to optimize the jet strip configuration. In particular, the jet strip

orifice size may contribute to washing away weaker fibers; such is the case with cotton

fibers and single knit constructions. A larger orifice construction may allow for a lower

specific energy to be used while still achieving desired results. Also, the jet strip that

was used did cause jet streaks and fiber damage at high energy of some of the cotton

samples. Experimenting with various jet strip configurations may improve the fabric

properties.

73

7 References AATCC Technical Manual, American Association of Textile Chemists and Colorists. 75 (2000). ASTM Technical Manual, Annual Book of ASTM Standards. 2004. Bitz, K. “Spunlacing Market Overview – A New Spin on Spunlace.” Nonwovens Industry; April 2001. Candan, C. and Onal L. “Dimensional, Pilling, and Abrasion Properties of Weft Knits Made from Open End and Ring Spun Yarns.” Textile Research Journal. (2002) 72(2): 164-169. Chiweshe, A. and Crews, P. “Influence of Household Fabric Softners and Laundry Enzymes on pilling and Breaking Strength.” Textile Chemist and Colorist and American Dyestuff Reporter. (2000) 32(9): 41-47. Cooke, W.D. “Textile Institute.” (1983) 74 (3): 101. Goktepe, O. “Fabric pilling performance and sensitivity of several pilling testers.” Textile research Journal. (2002) 72 (7): 625-630. Hsi, C., Bresee, R., and Annis, P. “Characterizing Fabric Pilling by Using Image Analysis Techniques, Part I: Pill Detection and Description.” Textile Institute. (1998) 89 (1): 80-95. Hsi, C., Bresee, R., and Annis, P., “Characterizing Fabric Pilling by Using Image Analysis Techniques, Part II: Comparison with Visual Pill Rating.” Textile Institute (1998) 89 (1): 96 – 105. Kim, H. And Pourdeyhimi, B. “Characterizing fabric pilling due to fabric-to-fabric abrasion.” Textile Research Journal. (2001) 71 (7): 640-644. Okubayashi, S., Campos R., Rohrer C., and Bechtold T. “A pilling Mechanism for Cellulosic Knit Fabrics- Effects of Wet Processing.” Journal of the Textile Institute. (2005) 96(1): 37-41. Ozdil, N. “Effect of yarn spinning systems on the pilling resistance of knitted fabrics. “ Knitwear technology (2002) 24(1): 20-21. Palmer, S. and Wang X. “Evaluating the robustness of objective pilling classification with the two-dimensional discrete wavelet transform.” Textile research Journal. (2004) 74 (2): 140-145.

74

Saraf, N., and Alat, D. “ Pilling of textiles: Causes and Remedies.” International Dyer. (2004) 189 (4): 23-24. Turi, M. “The Outlook of Spunlaced Nonwoven.” Nonwovens Industry; November 1988. United States Patent Office. Process for producing anti-pilling acrylic fiber August 17, 1976. Sekigucki, et al. Patent 3,975,486. United States patent Office. Process for producing acrylic synthetic fibers having anti-pilling properties May 27, 1980. Fujimatsu. Patent 4,205,037. United States Patent Office Stabilized fabric September 22, 1987. Dyer, et al. Patent 4,695,500. United States Patent Office Apparatus and method for hydroenhancing fabric. August 11, 1992. Sternlieb, et al. Patent 5,136,761. United States Patent Office Method and device for hydrodynamic entanglement of the fibers of a fiber web June 9, 1998. Fleissner. Patent 5,761,778. United States Patent Office Methods for reduced pilling of towels April 18, 2000. Caldwell. Patent 6,051,034. United States Patent Office Fabric hydroenhancement method and equipment for improved efficiency May 6, 2003. Greenway, et al. Patent 6,557,223. Upkonmwan, J., Mukhopadhyay, A., and Chatterjee, K., “Pilling.” Textile Progress (1998); 28(3), 1 – 58.

75

Appendix

76

SAMPLE 1 SAMPLE 2 SAMPLE 3 SAMPLE 4 SAMPLE 5

1 SINGLE COTTON 181.2 186.6 187.5 188.7 187.92 SINGLE COTTON 194.3 200.4 202.4 203.4 203.73 SINGLE COTTON 187.5 200.0 199.6 202.2 195.84 SINGLE COTTON 178.3 180.8 185.5 189.1 185.15 SINGLE COTTON 181.1 177.1 182.6 175.5 181.46 SINGLE COTTON 173.2 167.3 167.4 175.1 182.27 SINGLE POLY 136.9 139.1 108.7 129.0 143.18 SINGLE POLY 164.7 168.4 173.1 167.3 175.29 SINGLE POLY 156.6 154.0 160.0 157.1 160.410 SINGLE POLY 192.1 190.6 188.1 191.4 189.611 SINGLE POLY 170.2 168.9 169.5 172.4 171.912 SINGLE POLY 185.5 196.8 194.0 199.4 193.813 SINGLE BLEND 128.9 133.3 128.1 131.0 136.414 SINGLE BLEND 159.8 163.3 159.2 162.8 161.815 SINGLE BLEND 146.3 147.5 147.0 150.2 148.016 SINGLE BLEND 156.4 158.6 142.7 157.5 158.417 SINGLE BLEND 155.6 157.6 155.0 160.4 158.018 DOUBLE COTTON 329.3 326.6 324.3 324.4 333.119 DOUBLE COTTON 391.9 385.7 382.7 377.3 382.120 DOUBLE COTTON 391.0 394.7 391.1 389.3 395.521 DOUBLE COTTON 367.4 360.9 349.8 350.3 370.822 DOUBLE COTTON 410.8 408.4 408.4 410.9 404.523 DOUBLE COTTON 398.8 397.2 393.7 398.6 401.724 DOUBLE POLY 251.0 258.2 253.1 260.3 264.625 DOUBLE POLY 335.7 330.8 332.6 332.8 335.726 DOUBLE POLY 349.8 339.3 340.8 343.3 344.427 DOUBLE POLY 330.0 330.9 325.0 328.4 334.128 DOUBLE POLY 355.9 342.8 343.1 343.2 362.029 DOUBLE BLEND 265.2 266.4 262.0 263.8 262.930 DOUBLE BLEND 296.5 289.3 286.1 291.5 293.631 DOUBLE BLEND 291.9 309.5 300.9 305.5 314.832 DOUBLE BLEND 296.8 285.0 288.4 282.6 296.433 DOUBLE BLEND 296.1 298.5 295.4 293.1 304.2

GSMTRIAL KNIT FIBER

Figure 80: Weight Data

77

SAMPLE 1

SAMPLE 2

SAMPLE 3

SAMPLE 4

SAMPLE 5

1 SINGLE COTTON 323 327 338 325 3132 SINGLE COTTON 128 135 132 135 1353 SINGLE COTTON 127 128 129 127 1274 SINGLE COTTON 96.4 122 99 104 1275 SINGLE COTTON 142 135 135 128 1246 SINGLE COTTON 109 104 104 109 1037 SINGLE POLY 516 507 544 556 5878 SINGLE POLY 355 360 375 333 3729 SINGLE POLY 241 294 302 256 29710 SINGLE POLY 214 202 200 202 20011 SINGLE POLY 250 286 266 251 27512 SINGLE POLY 211 192 182 189 18213 SINGLE BLEND 564 555 569 530 52514 SINGLE BLEND 305 278 254 266 27415 SINGLE BLEND 254 253 272 259 26116 SINGLE BLEND 259 238 234 243 22917 SINGLE BLEND 265 279 279 277 28118 DOUBLE COTTON 144 139 133 123 12519 DOUBLE COTTON 37.2 38 37.3 36.5 38.220 DOUBLE COTTON 26.1 26.1 25.8 26.4 26.121 DOUBLE COTTON 30.2 33.3 32.5 31.1 28.122 DOUBLE COTTON 29.1 31.8 32.8 32 31.323 DOUBLE COTTON 36.3 37.8 34.6 34.7 34.224 DOUBLE POLY 253 240 239 239 23525 DOUBLE POLY 69.4 72 73.8 73.8 70.126 DOUBLE POLY 58.3 59.7 59.8 61.1 59.927 DOUBLE POLY 117 122 121 116 11428 DOUBLE POLY 50.7 54.7 52.8 52.9 52.329 DOUBLE BLEND 245 248 257 249 23730 DOUBLE BLEND 56.8 58.8 53.2 53.9 57.731 DOUBLE BLEND 42.9 46.8 45.5 44.5 43.832 DOUBLE BLEND 55.4 60 62.8 60.4 60.533 DOUBLE BLEND 70.6 70.1 75.1 73.5 72.8

CFMTRIAL KNIT FIBER

Figure 81: Air Permeability Data

78

SAMPLE KNIT FIBERASTM

RATINGOPTICAL RATING

1 SINGLE COTTON 1.0 2092 SINGLE COTTON 4.5 1303 SINGLE COTTON 5.0 1094 SINGLE COTTON 5.0 815 SINGLE COTTON 5.0 546 SINGLE COTTON 5.0 977 SINGLE POLY 1.0 1658 SINGLE POLY 1.0 1699 SINGLE POLY 3.0 13710 SINGLE POLY 4.0 13011 SINGLE POLY 3.5 13312 SINGLE BLEND 1.0 16713 SINGLE BLEND 1.0 39814 SINGLE BLEND 4.0 31015 SINGLE BLEND 4.0 25116 SINGLE BLEND 4.5 22717 SINGLE BLEND 5.0 13118 DOUBLE COTTON 3.0 17019 DOUBLE COTTON 4.0 5220 DOUBLE COTTON 5.0 5421 DOUBLE COTTON 4.0 6822 DOUBLE COTTON 5.0 4123 DOUBLE COTTON 5.0 6224 DOUBLE POLY 1.5 20425 DOUBLE POLY 1.0 27026 DOUBLE POLY 2.5 22627 DOUBLE POLY 4.5 18128 DOUBLE POLY 4.5 12329 DOUBLE BLEND 1.0 22630 DOUBLE BLEND 2.5 18531 DOUBLE BLEND 2.0 20532 DOUBLE BLEND 4.0 13733 DOUBLE BLEND 4.5 111

Figure 82: Pill Rating Data

79

SAMPLE 1

SAMPLE 2

SAMPLE 3

SAMPLE 4

SAMPLE 5

1 SINGLE COTTON 0.5334 0.527812 0.535686 0.537972 0.544832 SINGLE COTTON 0.63119 0.639572 0.611886 0.618998 0.6103623 SINGLE COTTON 0.59055 0.5969 0.595884 0.593598 0.6004564 SINGLE COTTON 0.555498 0.568452 0.517144 0.517144 0.532135 SINGLE COTTON 0.524256 0.491998 0.539496 0.47244 0.519436 SINGLE COTTON 0.606044 0.611124 0.610616 0.600202 0.5885187 SINGLE POLY 0.418084 0.41148 0.421894 0.413512 0.4033528 SINGLE POLY 0.531368 0.533146 0.522986 0.51054 0.5377189 SINGLE POLY 0.469138 0.480568 0.454152 0.46609 0.47904410 SINGLE POLY 0.615696 0.629158 0.612902 0.615696 0.62382411 SINGLE POLY 0.482092 0.485648 0.486664 0.502666 0.48793412 SINGLE POLY 0.600202 0.614426 0.612902 0.60833 0.6134113 SINGLE BLEND 0.425704 0.405638 0.421132 0.403098 0.406414 SINGLE BLEND 0.477012 0.515112 0.508254 0.516128 0.50876215 SINGLE BLEND 0.48387 0.469392 0.494284 0.485648 0.44297616 SINGLE BLEND 0.489966 0.484378 0.487934 0.488696 0.49301417 SINGLE BLEND 0.546608 0.531876 0.538988 0.538988 0.52882818 DOUBLE COTTON 0.794512 0.783844 0.794766 0.786892 0.8089919 DOUBLE COTTON 0.98298 0.979678 0.994664 0.970788 0.99466420 DOUBLE COTTON 0.901954 0.93218 0.93345 0.936752 0.91744821 DOUBLE COTTON 0.83185 0.820928 0.811022 0.824992 0.7848622 DOUBLE COTTON 0.98044 1.00838 1.02006 1.00507 1.0203123 DOUBLE COTTON 1.0413 1.02235 1.03682 1.05994 1.0518124 DOUBLE POLY 0.62484 0.620776 0.62103 0.62357 0.63550825 DOUBLE POLY 0.85344 0.852932 0.855472 0.863346 0.8801126 DOUBLE POLY 0.890778 0.887222 0.901954 0.896366 0.90322427 DOUBLE POLY 0.924052 0.884936 0.891794 0.912622 0.89941428 DOUBLE POLY 0.886714 0.88011 0.8636 0.889 0.88036429 DOUBLE BLEND 0.638556 0.62865 0.631952 0.625602 0.65303430 DOUBLE BLEND 0.70993 0.647954 0.66167 0.6985 0.71856631 DOUBLE BLEND 0.708152 0.694182 0.72517 0.70993 0.7150132 DOUBLE BLEND 0.694182 0.710692 0.708152 0.705866 0.71729633 DOUBLE BLEND 0.842772 0.822198 0.842772 0.87249 0.864108

MMTRIAL KNIT FIBER

Figure 83: Thickness Data

80

SAMPLE 1 WALE

SAMPLE 1

COURSESAMPLE 2 WALE

SAMPLE 2

COURSESAMPLE 3 WALE

SAMPLE 3

COURSE

1 SINGLE COTTON 26.00 -1.50 24.00 -3.25 28.00 -2.002 SINGLE COTTON 9.00 -4.00 10.00 -3.00 7.75 -6.003 SINGLE COTTON 11.50 -5.50 11.00 -6.00 9.50 -6.504 SINGLE COTTON5 SINGLE COTTON 16.50 -6.00 14.00 -7.50 13.50 -9.006 SINGLE COTTON 5.50 -5.00 6.50 -5.00 3.00 -8.507 SINGLE POLY 16.50 0.00 17.00 3.50 13.50 6.008 SINGLE POLY 4.00 3.50 4.00 -2.009 SINGLE POLY -0.50 0.50 1.25 1.25 0.75 -1.0010 SINGLE POLY 1.25 0.50 2.25 2.00 0.00 -2.0011 SINGLE POLY 3.25 -1.50 6.00 -3.50 3.75 -4.0012 SINGLE POLY 2.50 -2.75 2.50 -2.50 2.25 0.0013 SINGLE BLEND14 SINGLE BLEND 2.50 1.00 2.00 0.7515 SINGLE BLEND 13.50 -4.50 14.00 -10.00 12.00 -12.0016 SINGLE BLEND17 SINGLE BLEND18 DOUBLE COTTON 33.00 -8.00 29.00 -8.00 30.00 -8.5019 DOUBLE COTTON 14.00 -6.50 11.00 -8.50 16.25 -9.7520 DOUBLE COTTON 12.50 -8.00 9.00 -6.50 14.00 -13.0021 DOUBLE COTTON 13.50 -10.00 16.50 -12.00 25.00 -12.0022 DOUBLE COTTON 4.25 -4.00 4.00 -5.00 4.00 -4.0023 DOUBLE COTTON 3.50 -1.50 3.50 -1.50 3.00 -5.0024 DOUBLE POLY 15.50 0.00 14.50 -0.75 14.00 -2.0025 DOUBLE POLY 2.50 -2.50 2.75 -2.25 2.25 -2.0026 DOUBLE POLY 3.50 -4.00 3.00 -2.75 3.50 -4.2527 DOUBLE POLY 4.25 -3.50 4.00 -4.25 4.50 -5.5028 DOUBLE POLY 3.50 -3.00 2.50 -3.00 1.75 -3.2529 DOUBLE BLEND 19.75 -2.50 19.00 -5.00 18.00 -2.2530 DOUBLE BLEND 6.00 -5.50 4.50 -5.00 5.00 -6.5031 DOUBLE BLEND 7.25 -8.50 5.50 -8.00 6.00 -11.0032 DOUBLE BLEND 6.75 -6.00 6.25 -5.50 7.75 -5.7533 DOUBLE BLEND 2.25 -2.25 3.25 -5.00 2.00 -4.00

LOSS PERCENTAGETRIAL KNIT FIBER

Figure 84: Wash Shrinkage Data

81

1 SINGLE COTTON 106.42 SINGLE COTTON3 SINGLE COTTON4 SINGLE COTTON5 SINGLE COTTON 94.96 SINGLE COTTON7 SINGLE POLY 115.28 SINGLE POLY9 SINGLE POLY10 SINGLE POLY11 SINGLE POLY 124.512 SINGLE POLY13 SINGLE BLEND 131.814 SINGLE BLEND 115.815 SINGLE BLEND16 SINGLE BLEND17 SINGLE BLEND 104.718 DOUBLE COTTON 191.419 DOUBLE COTTON20 DOUBLE COTTON 203.621 DOUBLE COTTON22 DOUBLE COTTON23 DOUBLE COTTON24 DOUBLE POLY 222.425 DOUBLE POLY26 DOUBLE POLY27 DOUBLE POLY28 DOUBLE POLY29 DOUBLE BLEND30 DOUBLE BLEND31 DOUBLE BLEND32 DOUBLE BLEND33 DOUBLE BLEND 200.7

TRIAL KNIT FIBER AVG (PSI)

Figure 85: Mullen Burst Data

82

SAMPLE 1

SAMPLE 2

SAMPLE 3

1 SINGLE COTTON 84 82 752 SINGLE COTTON 82 86 87.53 SINGLE COTTON 89 79 83.54 SINGLE COTTON 74 63 635 SINGLE COTTON6 SINGLE COTTON 22 25 237 SINGLE POLY 93 91 91.58 SINGLE POLY 85 87.5 909 SINGLE POLY10 SINGLE POLY 73 70 7311 SINGLE POLY 98 89 8612 SINGLE POLY 76 72.5 7513 SINGLE BLEND 89.5 106.5 10114 SINGLE BLEND 91 78.5 9315 SINGLE BLEND 102 95 108.516 SINGLE BLEND17 SINGLE BLEND18 DOUBLE COTTON 113 112.5 11119 DOUBLE COTTON 95.5 95.5 9420 DOUBLE COTTON21 DOUBLE COTTON22 DOUBLE COTTON 103.5 103.5 98.523 DOUBLE COTTON24 DOUBLE POLY 117.5 116 11725 DOUBLE POLY 104.5 104 10326 DOUBLE POLY27 DOUBLE POLY28 DOUBLE POLY 117 106 10629 DOUBLE BLEND 116 117.5 119.530 DOUBLE BLEND 118 12031 DOUBLE BLEND32 DOUBLE BLEND 117 116.5 11833 DOUBLE BLEND

TRIAL KNIT FIBER

Figure 86: Ball Burst Data

83

Figure 87: Sled Friction Data

84

SAMPLE 1

SAMPLE 2

SAMPLE 3

SAMPLE 4

SAMPLE 5

SAMPLE 6

1 SINGLE COTTON 14744.7 18195 23322.3 16837.9 18043.7 23937.82 SINGLE COTTON3 SINGLE COTTON 13004.1 16186.1 19411 12944 14079.5 20541.84 SINGLE COTTON5 SINGLE COTTON 18827.3 27458.2 33395.5 27553.5 38191.4 41530.86 SINGLE COTTON7 SINGLE POLY 31074.8 44175.7 45967.9 37633.2 42473.1 52301.58 SINGLE POLY9 SINGLE POLY10 SINGLE POLY11 SINGLE POLY12 SINGLE POLY 15309.2 18423.8 18500.7 19794.6 20359.5 22904.013 SINGLE BLEND 14938.9 21023.4 26060.5 16738.0 18262.1 25321.914 SINGLE BLEND15 SINGLE BLEND16 SINGLE BLEND17 SINGLE BLEND 15190.4 20337.1 27970.0 20523.6 22977.4 30043.018 DOUBLE COTTON 14856.2 14815.4 14215.5 15989.5 14835.1 18307.019 DOUBLE COTTON20 DOUBLE COTTON21 DOUBLE COTTON22 DOUBLE COTTON23 DOUBLE COTTON 106.250 150.220 569.740 522.820 120.620 109.42024 DOUBLE POLY 6778.1 8851.4 9784.7 6642.4 8330.3 11731.325 DOUBLE POLY26 DOUBLE POLY27 DOUBLE POLY28 DOUBLE POLY 12520.5 16929.2 18046.6 15146.1 17626.3 20500.129 DOUBLE BLEND 28773.8 38614.6 37127.3 35151.8 40800.8 47224.530 DOUBLE BLEND31 DOUBLE BLEND32 DOUBLE BLEND33 DOUBLE BLEND 12025.5 16313.1 18738.4 15422.4 17402.1 19982.9

TRIAL KNIT FIBER gm/(m^2*day)

Figure 88: MOCON (WVTR) Data

85

SPECIFIC ENERGY (KJ/KG)0 2000 4000 6000 8000

MU

LLEN

BU

RST

STR

ENG

TH (P

SI)

90

95

100

105

110

115

Figure 89: Single Cotton Mullen Burst Strength

SPECIFIC ENERGY (KJ/KG)0 200 400 600 800 1000

MU

LLEN

BU

RST

STR

ENG

TH (P

SI)

180

185

190

195

200

205

210

215

220

Figure 90: Double Cotton Mullen Burst Strength

86

SPECIFIC ENERGY (KJ/KG)0 2000 4000 6000 8000 10000 12000

MU

LLEN

BU

RST

STR

ENG

TH (P

SI)

100

105

110

115

120

125

130

Figure 91: Single Polyester Mullen Burst Strength

SPECIFIC ENERGY (KJ/KG)0 5000 10000 15000 20000 25000

MU

LLEN

BU

RST

STR

ENG

TH (P

SI)

90

100

110

120

130

140

150

Figure 92: Single Blend Mullen Burst Strength

87

SPECIFIC ENERGY (KJ/KG)0 5000 10000 15000 20000 25000

CO

EFFI

CIE

NT

OF

FRIC

TIO

N

0.12

0.14

0.16

0.18

0.20

0.22

0.24

0.26

0.28

0.30STATIC FRICTION vs SPECIFIC ENERGYKINETIC FRICTION vs SPECIFIC ENERGY

Figure 93: Single Cotton Coefficient of Friction

SPECIFIC ENERGY (KJ/KG)0 2000 4000 6000 8000 10000

CO

EFFI

CIE

NT

OF

FRIC

TIO

N

0.10

0.12

0.14

0.16

0.18

0.20

0.22

0.24

0.26

0.28STATIC FRICTION vs SPECIFIC ENERGYKINETIC FRICTION vs SPECIFIC ENERGY

Figure 94: Double Cotton Coefficient of Friction

88

SPECIFIC ENERGY (KJ/KG)0 5000 100001500020000250003000035000

CO

EFFI

CIE

NT

OF

FRIC

TIO

N

0.05

0.10

0.15

0.20

0.25

0.30

0.35STATIC FRICTION vs SPECIFIC ENERGYKINETIC FRICTION vs SPECIFIC ENERGY

Figure 95: Single Polyester Coefficient of Friction

SPECIFIC ENERGY (KJ/KG)0 1000 2000 3000 4000 5000 6000

CO

EFFI

CIE

NT

OF

FRIC

TIO

N

0.05

0.10

0.15

0.20

0.25

0.30STATIC FRICTION vs SPECIFIC ENERGYKINETIC FRICTION vs SPECIFIC ENERGY

Figure 96: Double Polyester Coefficient of Friction

89

SPECIFIC ENERGY (KJ/KG)0 5000 10000 15000 20000 25000

CO

EFFI

CIE

NT

OF

FRIC

TIO

N

0.05

0.10

0.15

0.20

0.25

0.30STATIC FRICTION vs SPECIFIC ENERGYKINETIC FRICTION vs SPECIFIC ENERGY

Figure 97: Single Blend Coefficient of Friction

SPECIFIC ENERGY (KJ/KG)0 2000 4000 6000 8000 10000 12000

CO

EFFI

CIE

NT

OF

FRIC

TIO

N

0.05

0.10

0.15

0.20

0.25

0.30STATIC FRICTION vs SPECIFIC ENERGYKINETIC FRICTION vs SPECIFIC ENERGY

Figure 98: Double Blend Coefficient of Friction

90