Flexible Packaging Flexible Packaging Design & SelectionDesign & Selection

Bhupendra Singh

PACKAGING FUNCTIONS

Package is the means of providing

PROTECTION CONTAINMENT

PRESENTATIONIDENTIFICATION/

INFORMATION

CONVENIENCE

BRAND PROTECTION

PACKAGING FUNCTIONS

•• ““Packaging must protect Packaging must protect what it sells, and sell what it sells, and sell what it protectswhat it protects””

Flexible Packaging

Flexible Packaging is defined as construction made from flexible substrates.E.g. Paper, plastic films, aluminum foil

and other laminates. These materials can be coated or laminated.

Applications

A Flexible Pack Offers the Following Advantages: -

• Variety, reduction in size.• Convenience of storage resulting in

space saving.• Ease of opening and reclosing.• Light weight.• Disposability.

Components used :-• Paper, Metallic Foil, Cellophane, LDPE, HDPE,

Polypropylene, Polyester, Nylon, and Oriented Polypropylene etc.

Substrate combination selected On the Basis of:-

• Strength, printability, heat salability, opacity, barrier to moisture & oxygen and similar type of characteristic.

E.g Paper - Stiffness & printability Foil - Barrier properties & aesthetic appeal HDPE - Stiffness& low WVTR

Factors influencing Flexible Packaging Design & Selection

0 . Spoilage of Product1 . Factors Influencing

Pack Design2 . Factors Influencing Package

Material Selection

Spoilage of Product

0 . Spoilage of product results from

- Chemical Incompatibility between the

ingredients of the product / packaging material

-Moisture,

-Oxygen,

-Light &

-Temperature changes

Spoilage of Product

0 .1 Effects of Moisture

Ψ Crystalline substances absorb moisture, e.g.

CaCO3, Na-Sulphate

Ψ Aspirin can be hydrolyzed by water absorption

Ψ Vitamins are also susceptible to moisture

Ψ Suitable packaging material should be used to

prevent / reduce the effect of water / moisture.

Spoilage of Product

0 .2 Effects of Light & OxygenΨ Light has a catalyzing effect on degradation by

oxygen.Ψ The degradation products may be toxic.Ψ It is essential that light does not affect the

product.Ψ Suitable packaging material should be used (e.g.

Amber colour glass Bottle) to prevent / reduce the effect of light or the product should be modified if possible.

Spoilage of Product

0 .3 Effects of HeatΨ Heat can cause product to loose the water of

crystallization & convert the product into amorphous state.

Ψ The rate of vaporization of some products are affected by changes in heat (liquid products).

Ψ Many medications are deactivated / degraded by heat & exposure to light further accelerate the heating effect.

Ψ Suitable packaging material with adequate protection from heat should be used. Insulation may also be used along with coolant for long term transport & storage.

Spoilage of Product

0 .4 Effects of Other FactorsDistribution Hazards

• Mechanical Hazards of transportation• Climatic Hazards of distribution• Biological hazards of distribution• Compatibility

Spoilage of Product

0 .4.1Mechanical Hazards of transport• Hazards of loading & Unloading

• Drops, Height of drop

• Hazards of Movements– Rail : (Shunting Shocks, Vibration, Acceleration /

Deceleration hazards )

– Road : (Vibration, Bouncing of load, Acceleration / Deceleration hazards )

– Water : (Staking, Vibration hazards )

– Air : (Low pressure, High frequency Vibration hazards )

– Multi-modal Transport– Hazards of warehousing

Spoilage of Product

0 .4.2 Climatic Hazards of distribution

• Exposure to liquids/ water

• Exposure to vapour/ humidity

• Temperature Change (Low / High)

• Pressure Changes (Low / High)

• Dust storms

Spoilage of Product

0 .4.3 Biological Hazards of distribution

• Biological Hazards– Microorganisms

• Fungi

• Moulds

• Bacteria

– Insects• Beetle, Ants, Termites

– Mites

– Rodents

• Metal Containers• Fiber / Plywood• Drums• Multi-wall• Heavy-duty Plastics Sacks

Package Design - Bulk Packaging

FLEXIBLE PACKAGING –Manufacturing

(CO-EXTRUSION ANDLAMINATES)

Manufacturing processes of Flexible Composites

i. Laminationii. Extrusion coatingiii. Co-extrusion

LAMINATIONFLEXIBLE LAMINATES FOR

PACKAGINGIt consists of superimposed layers of plastics,

paper or foil bonded together by heat or adhesive or polymer melt to form a composite film of uniform thickness and flexibility.

A Laminate is defined flexible, when substantially parts of it can be folded to 180°without cracking and without the need of pre-crease.

Any desired properties can obtained by different combination.

TECHNIQUES OF LAMINATION

• Extrusion coating• Extrusion lamination • Adhesive lamination• Heat lamination • Wax lamination • Hot melt coating

1. Extrusion Coating• Involves the

application of molten polymer from an extruderto the surface of flexible substrate

• Polymer used is LDPE, EVA, HDPE, PP etc.

2) Extrusion lamination :-Hot extruded film is trapped between two other

webs and cooled.3) Adhesive lamination: -

Applying adhesive to one ply then combining with another

4) Heat Lamination :–Heat sealable performed film like polyethylene is

laminated to the backing substrate 5) Wax lamination :–

Molten wax is applied to one ply of material then combined with second ply.

APPLICATION

1) Cellophane/ Polyethylene/ Foil/ Polyethylene

Excellent gas barrier,sandwich printing wv resistance

Pharmaceutical tablets, chocolates.

2) Foil/ Adhesive/ Paper/ Polyethylene

WVbarrier, good machnability, good appearance.

Soup mixes, drink powder and dry milk solids.

APPLICATION3) Foil/ Polyethylene

Excellent barrier to gas, Water vapors and light

Hygroscopic products in strip packaging4) Polyamide/ Polyethylene

Good gas barrier, Good W V resistance, and Aroma retention.

Meat packing, cheese, boil in a bag pouches, heavy machinery parts.

Aluminum foil bearing laminates (food packaging)

• Waxed rappers:-foil /paper/wax• Toffee rappers;-foil/ adhesive/paper/wax • Food overwrapes:-foil/ adhesive/ paper• Boil in bag pouch:-PET/foil/LDPE• Instant coffee:- paper/ foil/ PE • Soft drink conc. :- glassine/foil/LDPE

(withstands product sterilization in package)• Retort pouch:- polyester/foil/HDPE• M.R.E package (meal ready to eat):- PET/ foil /PP

CO-EXTRUSION

Co-extruded film is defined as a multiplayer film in each distinct layer is formed by simultaneous extrusion process through a single die.

Co-extrusion allows one to prepare a multifunctional packaging material in one manufacturing step as opposed to traditional multistep process of coating and lamination.

TECHNOLOGY OF CO-EXTRUSION

• Extrusion of different polymers through different extruders.

• Combining them at a common die as different layers.

• Then blown by compressed air,which forms bubble between the die head and nip rollers

• The nip rollers make the tabular film in lay flats, passed on, to the winding and slitting unit.

• The compressed air settles the bubbles is important to create uniform width

Co-extrusion could be considered depending upon application and number as: -

• Two Layers• Three Layers• Five Layers or more

Extruder

Fig : Schematic illustration of a typical extruder for plastics, elastomers, and composite materials.

Sheet Extruder

Fig : Die geometry (coat-hanger) for extruding sheet.

Film Extruder

Fig : Schematic illustration of the production of thin film and plastic bags from tube first produced by an extruder and then blown by air.

Principle Processes utilizing Co-extrusion Technology

1. Cast Film Co-extrusion.2. Blown film Co-extrusion.3. Co-extrusion Coating.4. Co-extrusion Lamination5. Cast-sheet Co-extrusion.

Cast Film Co-extrusion:-

Main Focal Point of Technology in the Cast Film Process is a Design of Die.

Two Types of Dies used:-

Blown film Co-extrusion

Separate resins are extruded into a Circular die.The molten resin streams are blown into a bubble, cooled by air rings and collapsed in the primary nip. The tabular film is generally slit for specific packaging application.

PRINCIPLE RAW MATERIALS

• Polyolefin (polyethylene and polypropylene)

• HDPE-LDPE resin• Copolymers of Ethylene Vinyl Acetate

(EVA), Ethylene Acrylic Acid (EAA) and Ethylene Methacrylic Acid (EMA)

• nylon, polyvinylidine chloride, PVDC and ethylene-vinyl alcohol (EVOH)

RAW MATERIALS FOR LAMINATES

• Paper• Aluminum foil• Plastic film • Rubber hydrochloride• Regenerated cellulose

Materials Involved

• PET -- 10, 12 micron• BOPP -- 15 to 30 micron• Met PET -- 10, 12 micron• MetBOPP -- 15 to 30 micron• Foil – 7 to 12 micron• PE Sealant – 20 to 140 micron• Paper – Maplitho, Glassine, Kraft

Sealant Layer

• Polyethylene based -- LDPE, LLDPE,

• Metallocene LLDPE, Nylon PE, EVOH PE,

• MDPE, HDPE,

• Polypropelene Based -- CPP

PVDC

Acrylic

PVOH

LTS

Methyl Acrylic Acid

Matt

U. V. Varnish

Hotmelt

Heat Resistant

Holograph Effect

Release

Nano Composite Materia

Al203

Siox

SPECIALITY COATINGS

SIOX Coated Film

AL203 Coated Film

Methyl Acrylic Acid Coated Film

Breathable Films

PP / PE Composite Film

Susceptor Film

NEW BARRIER SUBSTRATES

MATERIAL COMBINATION AND PURPOSES

In multilayer film specific function of each layer can be obtained by designing a symmetrical or non-symmetrical structure.

A/B/C/B/A –symmetrical structure

A/B/C/B/D –non-symmetrical structure

For E.g. 3-layer co extrusion process one layer of material A, tie layer & material B.

tie layer consists of a chemically modified polymer that possesses good bonding properties for adhesion to material A as well as B.

Plasma

Metallizing process

MetallizedSubstrate

Wafer

Gas

Cathode Power Uncoated

PLASMA PROCESS

Combination Application Achievable Property

LDPE/LDPE Milk film Two colors

HDPE/EVA a) Blood plasma b) Food products

Good mechanical and sealing property

Nylon/Tie/EVOH/tie/ LLDPE

Ketch –up moisture & gas barrier

PP/HDPE/PA Cosmetics & pharmaceutical products.

Printable, scratch resistant surface

PP/Tie/ EVOH/Tie/ PP

Fruit juice Gas, steam & aroma barrier

ADVANTAGES OF CO-EXTRUSION OVER LAMINATION

• Eliminates the extra production cost involve in Adhesive Lamination.

• Eliminates the use of solvent-based adhesives • Reduce the amount of expensive polymer, by

reducing film thickness

DI SADVANTAGES OF CO-EXTRUSION

Laminate with sandwich printing can not be produced

Scraped produced can not be regranulated

Typical Structures for Typical applications

DESIGN

OPP OR PETPRINTADHESIVEFOIL OR METOPP

PE, OPP ORCPP

REVERSEPRINTEDFILM

BARRIER

SEALING

METALLISED

PRODUCT

ADHESIVE

LAMINATE STRUCTURE

Developments in Flexible Packaging

Biscuits

• BOPP / BOPP hs• BOPP / Met BOPP hs• BOPP / Met PE• PET / Met PET / PE

Biscuits

Biscuits

Candies :

Medium Barrier :• BOPP / CPP• PET / PE• PET / PP-PE

Candies – High Barrier

• BOPP / Met BOPP Hs

Candies :

Candies :

Chocolates :

Bars :

• Cold Seal For :1. Sealing without exposure to heat.2. Excellent seal integrity.3. High line speeds.4. “Registered”

Chocolates :

Chocolates :

Chocolates :

Cakes and bakery products :

Bakery products :

Snack Food

Gas Flushed

• PET / Met PET / PE

Snack Food

Snack Food

Beverages

TEA COFFEEPET / PE PET/Foil/PEBOPP / Paper / PE PET/Met PET/PE

Milk & Health drink

LDPE co-ex LLDPEPET / FOIL / PEPET / Met PET / PE

Milk & Health drink

Milk & Health drink

Ketch – Up

PET / Foil / PET / PEPET / Met PET / PEPET / PE / Foil / Special Poly

Retort Application

PET / Foil / CPP

Retort Application

Retort Application

Retort Application

Oil Packaging

• PET/PE• PET/Met PET/PE

Ice Creams

• BOPP / PE• PEARLISED BOPP hs

Vegetables

Vegetables

Vegetables

Vegetables

Other applications

Flexible Pack

Flexible Pack

Flexible Pack

Flexible Pack

Flexible Pack

Flexible Pack

BOND / SEAL STRENGTH

DYNAMIC / STATIC COF

COLD / HEAT SEAL

BALLOON BURST

SEAL LEAKAGE

BURSTING STRENGTH

ORGANOLEPTIC TESTS

COLOUR SPECTROMETER

INSPECTION / TESTS

OPTICAL DENSITY

DART IMPACT

COMPRESSION STRENGTH

BLOCKING MEASURE

SCUFF RESISTANCE

PIN HOLE MEASUREMENT

GAS CHROMOTOGRAPHY

OTHER RM TESTS

THICKNESSUNIT : (mm/GAUGE/Microns)EQUIPMENT : DIAL GAUGE MICROMETER

IMPORTANT PROPERTY - AFFECTING:• MECHANICAL PROPERTIES• SEALABILITY• BARRIER PROPERTIES• PERFORMANCE• PRODUCT PROTECTION.

TENSILE STRENGTH / ELONGATIONASTM D. 638

• IMPORTANT MECHANICAL PROPERTY.

• RESPONSIBLE FOR HIGH SPEED PACKAGING OPERATIONS.

• EQUIPMENT : INSTRON TYPE TENSILE TESTER.

• UNIT : kg/cm2

PERCENTAGE(%).

IMPACT RESISTANCEIS : 2508

• DART IMPACT TEST.• UNIT g f at 50% FAILURE• DROP HEIGHT : 66 CMS• DROP HEIGHT : 155 CMS.

STATIC COEFFICIENT OF FRICTIONASTM D.1894

• RELATED TO SLIP PROPERTIES.• TILTING PLANE METHOD• SLEDGE 200g.• AGE OF FILM• BLOOMING ACTION OF SLIP ADDITIVES.

KINETIC COEFFICIENT OF FRICTION ASTM D.1894

• FRICTION BETWEEN STEEL COLLAR AND FILM.

HEAT SEAL STRENGTHASTM F-88

DIRECTLY RELATED TO:

1. DWELL TIME ,TEMPERATURE , PRESSURE.2. SEAL CONTAMINATION.3. THICKNESS VARIATION.4. MFI.5. TYPE OF SEALANT LAYER• TYPE OF SEALING PROCESS (IMPULSE /

HIGH FREQUENCY / ULTRASONIC).• UNIT : kg/15 mm.• EQUIPMENT : TENSILE TESTER.

BOND STRENGTHASTM D-904.

• RELIABILITY OF CONTINUING ADHESION DURING PACKAGING, SEALING AND STORAGE.

• THE DEGREE OF BOND VARIES1. THE INFLUENCE OF OILS / SOLVENTS.2. THE ADHESIVE USED.3. THE QUANTITY OF ADHESIVE.4. AFFINITY TO MOISTURE.5. EXCESS SOLVENT RETENTION.6. CLIMATIC CONDITIONS.

UNIT : g / 15mm.EQUIPMENT : TENSILE TESTER.

WATER VAPOUR TRANSMISSION RATE IS 1060 –II, ASTM E-96, ASTM E-398

UNIT: (G/M2/24 HRS.) AT 38 ±1°C & 90± 2% RH.

• MOST IMPORTANT BARRIER PROPERTY FOR MOISTURE SENSITIVE PRODUCTS

• DECIDES SHELF LIFE OF THE PRODUCTS

• DIRECTLY PROPORTIONAL TO THICKNESS

• VARIES FROM POLYMER TO POLYMER

OXYGEN TRANSMISSION RATEASTM D – 3985.

1. MANOMETRIC METHOD.

2. CARRIER GAS (SENSOR).

• UNIT : cc / m2/ 24 hrs / ATM.

• MOST IMPORTANT PROPERTY FOR GAS SENSITIVE PRODUCTS

• VACCUUM PACKAGING / GAS PACKAGING MATERIALS

New Concepts/Materials

Holograms

Bar coding

Expanded content labels

RFID tags