Plastic Packaging

PACKAGING Archna.R Gokulnath.P Monikumar.S Subha.S

Introduction • Enclosing of physical object – protection from tampering. • provides barrier between enclosed product and its environment. Purpose • protection against physical impact on object, dust and dirt. • agglomeration • Information transmission • Marketing • Prevention of pilferage & tampering

MATERIALS USED IN PACKAGING NAME PROPERTIES HDPE Milky,tran -slucent

APPLICATIONS Milk-bottle, detergent bottle,household chemical bottles,pallet s,bags,sacks.

ADVANTAGE Readily pigmentedattractive colours.

DISADVANTAGE Environmental stress cracking (reduces with comonomer)

MATERIALS USED LDPE

Soft, flexible

Films, Bags

Better clarity than HDPE HP-LDPE Good Films Higher heat seal and bags heat seal material temperature & narrow range

Too soft

Not much toughnes s, stiffness.

MATERIALS USED LDPE

Toughn- Bags & ess, films Stiffness & high barrier property.

Yield stray films at thinner gauge.

Polystyrene

Highly Foam Easy to transpar- packagi- extrude ent ng and thermoform

Cost is more

Brittleness(reduc -ed with rubber)

MATERIALS USED PET

Small crystallites, transparency Nylons Semi (polyami crystallides) ne with thermal stability

Soft drink bottles, ovenable tray. Bags vacuum & medical packages

Better Low melt O2 & strength CO2 resistance. Low Yield strength & flex strength

MATERIALS USED PVC

Good transparency, slight bluish tint

Polycar- Slight bonate yellowish tinge

Water bottles, Thermoformed blisters, stretch wrap Medical, water bottles

Good barrier property, soft & flexible

Level of residual vinyl monomer

Tough, rigid & impact strength

Poor chemical resistance

TYPES OF PACKAGING • Child-Resistant Packaging • Tamper-Evident Packaging • Flexible Packaging • Foam Packaging • Aseptic Packaging

Child-Resistant Packaging • • • • • •

To prevent children from toxicity in product Two designs of packaging Cap must be pressed down and turn Pull-up and turn In form of blisters and pouches Paper and aluminium foil with plastic

Tamper-Evident Packaging • To provide consumer with evidence • Involves plastic packaging • plastic over wraps around containers,plastic neckbands,and inner seals • Grown particularly in food areas • Also termed as freshness seal

Flexible-Packaging • • • •

polarized light used to examine heat seals Bi-refringence patterns guides seal interface Hermatic seals to avoid wrinkles Contamination in seal area to be removed

Foam Packaging • Plastic foam,packaging as cushioning material also used as containers • Polystyrene,urethanes,polyethylene,and polypropylene are used as materials • Classified in to open cell and closed cell • Closed cell are less absorbent than open cell

Aseptic Packaging • • • •

Sterilizing the product with heat Package with hydrogen peroxide Milk,egg mix,soups,juices and liquid foods By canning process

Aseptic Packaging • Convenience-portable,high weight,shatter proof and easy transporting • Food safety-prevent food from harmful bacteria and contaminants • No refrigeration-can be placed in cabinets • More nutrition-less heat than canning so product retain natural taste,color,and texture

Applications Of Packaging • • • • • •

Milk and dairy foods are packaged To maintain product hygiene Protects nutrition and flavour Reduce food spoilage and waste Increase food availability Enable efficient food distribution and to communicate storage instructions

Types Of Packaging In Milk Products • • • •

Cartons-covered by polyethylene plastic Plastic bottles-made of HDPE ,PE ,PET HDPE and PET does not spoil the milk Containers-polystyrene plastics are used to produce tubs and pots for milk packaging

MEDICAL PACKAGING • Polymer films protect the enclosed packaging. • The films are single or laminated structure of polymer films. • Prevents moisture, O2, light, other gases – permeating package structure. • Films can be folded or creased without – structural weakness. • Common types of sterilization – ethylene oxide and gamma radiation. • Gas is introduced – evacuated after destroying micro organisms.

FILM STRUCTURES Coextrusion • Two or more polymers coextruded through single die. • Materials – LDPE, Polypropylene, PVC, Polyamides, Polystyrene. • Features – low gas permeation rate. Lamination • Created when two or more films bonded with special adhesives – through rolling, heated cylinders.

FILM STRUCTURES Lamination • Materials - polyethylene - cellophane, polypropylene – cellophane. • Materials are tested and suitable adhesives are used. Metallization • Developed by vaporizing metal, depositing to polymer web and applying to film. • Aluminum – most commonly used.

FILM STRUCTURES Coating • Application of various materials to film web substrate to impart special features and properties. • Materials – Teflon, polyvinylidene chloride, polyvinylidene fluoride.

BLISTER PACKAGING • Used to make child resistant packaging • Medical application – pouches, diagnostic test kits & disposables. • Two types – 1. push through lidding – tablet or capsule- PVC, PET, polyvinylidene chloride. 2. peelable lidding – sealed packet with or without special adhesives – tyvek coating, polyester coating, polyvinyl acetate.

Different Technique Followed in Packaging • • • • •

Injection Moulding Injection Blow Moulding Extrusion Blow Moulding Positive Thermoforming Negative Thermoforming

Injection Moulding • For Producing Caps and Lids • Uses two stage Extruders,for plasticizing and injection functions • Made of high quality tool grade steel and so expensive • Polymers used have relatively low viscosities • Temperature plays main role

Injection Moulding

Closures • Critical parts of packing System • Has to rectify the errors occurred during the manufacture of Containers • Polypropylene- the most widely used • Polystyrene, HDPE, LDPE and PVC are also used

Closures- Categories • Friction Closures- for Cork typed • Snap on Closures- for Child resistant • Threaded Closures- for those at pressure(Example- Carbonated Beverages)

Blow Moulding • Extrusion Blow Moulding

• Injection Blow Moulding

Extrusion Blow Moulding • Used for Producing Plastic Bottles • Extrusion is in Downward Direction

Injection Blow Moulding • Used for producing Bottles • Two moulds are used • Mold has two halves of cavities and a core rod • Preferred for small bottles • Polystyrene and PET are most commonly used

Injection Blow Moulding

Thermoforming • Used for making Cups, Egg Cartons, Trays etc.. • More than 75% of thermoforming applications are in packaging • HIPS is used • Maintaining temperature is important in Thermoforming

Types of Thermoforming Positive Thermoforming * Convex mould is used * Preferred when tolerances on inside of package are critical Negative Thermoforming * Concave mould is used * Better material distribution, faster cooling than positive thermoforming