Flexible Package Design

Flexible Packaging Design & Selection Bhupendra Singh

PACKAGING FUNCTIONS Package is the means of providing CONTAINMENT

PROTECTION

IDENTIFICATION/ PRESENTATION

INFORMATION

CONVENIENCE BRAND PROTECTION

PACKAGING FUNCTIONS

• “Packaging must protect what it sells, and sell what 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 Basis of:-

On the

• 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 Product 1 . Factors Influencing Pack Design 2 . 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 & Oxygen Ψ

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 Heat Ψ

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 Factors • • • •

Distribution 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

Package Design - Bulk Packaging

• • • • •

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

FLEXIBLE PACKAGING – Manufacturing (CO-EXTRUSION AND LAMINATES)

Manufacturing processes of Flexible Composites i. Lamination ii. Extrusion coating iii. Co-extrusion

LAMINATION

FLEXIBLE LAMINATES FOR PACKAGING It 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 precrease. Any desired properties different combination.

can

obtained

by

• • • • • •

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 extruder to 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.

APPLICATION 3) Foil/ Polyethylene Excellent barrier to gas, Water vapors and light Hygroscopic products in strip packaging 4) 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. 2. 3. 4. 5.

Cast Film Co-extrusion. Blown film Co-extrusion. Co-extrusion Coating. Co-extrusion Lamination 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

SPECIALITY COATINGS PVDC

Hotmelt

Acrylic

Heat Resistant

PVOH

Holograph Effect

LTS

Release

Methyl Acrylic Acid

Nano Composite Materia

Matt U. V. Varnish

Al203 Siox

NEW BARRIER SUBSTRATES

SIOX Coated Film AL203 Coated Film Methyl Acrylic Acid Coated Film Breathable Films PP / PE Composite Film Susceptor Film

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 PROCESS

Wafer

Gas

Metallizing process

Plasma

Uncoated

Cathode Power

Metallized Substrate

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/EVO Ketch –up H/tie/ LLDPE

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

LAMINATE STRUCTURE

REVERSE PRINTED FILM

OPP OR PET

DESIGN

PRINT ADHESIVE

BARRIER

METALLISED

FOIL OR METOPP ADHESIVE

SEALING

PRODUCT

PE, OPP OR CPP

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 : • 1. 2. 3. 4.

Cold Seal For : Sealing without exposure to heat. Excellent seal integrity. High line speeds. “Registered”

Chocolates :

Chocolates :

Chocolates :

Cakes and bakery products :

Bakery products :

Snack Food Gas Flushed • PET / Met PET / PE

Snack Food

Snack Food

Beverages TEA PET / PE BOPP / Paper / PE

COFFEE PET/Foil/PE PET/Met PET/PE

Milk & Health drink LDPE co-ex LLDPE PET / FOIL / PE PET / Met PET / PE

Milk & Health drink

Milk & Health drink

Ketch – Up PET / Foil / PET / PE PET / Met PET / PE PET / 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

INSPECTION / TESTS

BOND / SEAL STRENGTH

OPTICAL DENSITY

DYNAMIC / STATIC COF

DART IMPACT

COLD / HEAT SEAL

COMPRESSION STRENGTH

BALLOON BURST

BLOCKING MEASURE

SEAL LEAKAGE

SCUFF RESISTANCE

BURSTING STRENGTH

PIN HOLE MEASUREMENT

ORGANOLEPTIC TESTS

GAS CHROMOTOGRAPHY

COLOUR SPECTROMETER

OTHER RM TESTS

THICKNESS UNIT : (mm/GAUGE/Microns) EQUIPMENT : DIAL GAUGE MICROMETER IMPORTANT PROPERTY - AFFECTING: • MECHANICAL PROPERTIES • SEALABILITY • BARRIER PROPERTIES • PERFORMANCE • PRODUCT PROTECTION.

TENSILE STRENGTH / ELONGATION ASTM D. 638

• IMPORTANT MECHANICAL PROPERTY. • RESPONSIBLE FOR HIGH SPEED PACKAGING OPERATIONS. • EQUIPMENT : INSTRON TYPE TENSILE TESTER. • UNIT : kg/cm2 PERCENTAGE(%).

IMPACT RESISTANCE IS : 2508 • • • •

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

STATIC COEFFICIENT OF FRICTION ASTM

• • • • •

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 STRENGTH ASTM F-88 DIRECTLY RELATED TO: 1. 2. 3. 4. 5. • • •

DWELL TIME ,TEMPERATURE , PRESSURE. SEAL CONTAMINATION. THICKNESS VARIATION. MFI. TYPE OF SEALANT LAYER TYPE OF SEALING PROCESS (IMPULSE / HIGH FREQUENCY / ULTRASONIC). UNIT : kg/15 mm. EQUIPMENT : TENSILE TESTER.

BOND STRENGTH ASTM D-904. •

RELIABILITY OF CONTINUING ADHESION DURING PACKAGING, SEALING AND STORAGE.

• 1. 2. 3. 4. 5. 6.

THE DEGREE OF BOND VARIES THE INFLUENCE OF OILS / SOLVENTS. THE ADHESIVE USED. THE QUANTITY OF ADHESIVE. AFFINITY TO MOISTURE. EXCESS SOLVENT RETENTION. 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 RATE ASTM 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

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