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BASICS OF YARN TECHNOLOGY
RAW MATERIAL
The basic raw material for Filament Yarn is derived from the
following Polymers.
POLYAMIDE (PA)
POLYESTER (PES)
POLYPROPYLENE (PP)
POLYAMIDE is stronger than PES & PP and with excellent
resistance against
abrasion,sunlight,water absorption and weather. But it develops
yellow tint under
sunlight.
Application : Umbrella,Raincoat,Packing Bag etc.
POLYESTER is easily washable and has good elastic
properties.
Application : Textile Clothing Material
POLYPROPYLENE Withstands high temperature.Clothes produced from
this
material have no wrinkles but have high static electricity.
Application : Fashion Carpets
YARN CHEMISTRY
POLYMARISATIONA combination or association of molecules that may
be of one or more compounds
reacting simultaneoulsy or consecutively to form a regular
system of molecules,
which behaves and reacts primarily as one unit termed
Polymer.
POLYESTERPolyester is by far the most widely used material for
yarn production. This is
manufactured fibre in which fibre forming substances in any long
chain synthetic
polymer composed of at least 85% by weight of an ester of
dihydric alcohol and
terephthalic acid.
Raw materials for Polyester Fibre Manufacture
DMT : Dimethyl Terephthalete PTA : Purified Terephthalic
acid
MEG : Monoethylene Glycol
SPINNING PROCESS
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The polymers are processed in spinning machines to get filament
yarns. Filament is
a single monofilament of a yarn eg. yarn specification 68 f 32
means, the yarn is of
68 Denier and with 32 monofilaments.
In the spinning process,fibre forming polymer substances in a
plastic/ molten state
are forced through the holes of a spinneret/die at a controlled
rate of extrusion intoair or gas where it is cooled and
solidified.The spun yarn is wound in suitable
packages for marketing
DENIER : Definition
Denier is a measure of linear density of yarn,the weight in gms
of 9000 metres of
yarn eg: 80 Denier means that the weight of 9000 metres of the
yarn is 80 gms.
D.TEX : Definition
D.Tex is also a measure of linear density of yarnD.Tex : No.of
gms per 10,000m of yarn
eg. 80 D.Tex : Weight of 10,000m of yarn = 80 gm
YARN ORIENTATION
Oriented Yarn from spinning line is classified as under
FOY : Fully Oriented Yarn HOY : Highly Oriented Yarn POY :
Partially Oriented Yarn MOY : Medium Oriented Yarn
LOY : Low Oriented Yarn
reffered direction of linear molecules in the fine structure of
fibers, usually caused
by stretching an extruded fibre so that length direction of the
molecules tends to lie
paralled to the main axis of the fibre.TEXTURISING PROCESS
yarn at controlled tension and speed is passed through a
rotating set of Ceramic or
Polyurethane Friction Discs mounted on spindle bearings in a
Friction Unit,which is
a part of Draw Texturising Machine.The yarn gets frictional
"Twist" and "Untwist"
on passing through the Friction Unit and develops "Yarn
Bulk".The is called false
twist because the twist does not remain,but a memory of the
twist remains and gives
the yarn torque or stretch as well as the bulk. The yarn passes
through Primary
Heater prior to Friction Unit and then through Secondary Heater
to heat set the
bulk. The relative speed between disc and yarn plays a major
roll in bulking. D/Y
ratio is the ratio of the yarn speed (M/min) and the friction
disc surface speed,which
controls the amount of friction between the rotating discs and
the running yarn.Yarn Path in Texturising
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InputYarn is fed through Bobbins mounted on a creel.Process :
through Primary Heaters,Feed Units,Friction Unit, Secondary
heaters,spin finish oil system etc.>
Output : Texturised Yarn is wound on Bobbins mounted in a
Take-up Unit, in
suitable packages for marketing.
The Texturising Machine
Draw Texturising Machine gets power input through a set of DC or
AC Motors with
a suitable Control Panel for speed control as also to monitor
various yarn process
parameters such as yarn speed,Temperatures, D/Y ratio, No.of
Double strokes per
min.etc.
