Plastic Packaging

PLASTIC PACKAGING COSTALES

LECHAGO

CRUZ

PASCUAL

ESCALANTE

TEODORO

INTRODUCTION LECHAGO, HARVEY

Polymer Chemistry Polymer Chemistry CRUZ, ANTHONY

TYPES OF PLASTIC Thermoplastics Thermosetting Plastic

Thermoplastic ◦

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is a plastic material, polymer, that becomes pliable or moldable above a specific temperature and solidifies upon cooling associate through intermolecular forces, which weaken rapidly with increased temperature, yielding a viscous liquid

Thermoplastic 2 classifications by structure: ◦

Crystalline Polymers

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Amorphous Polymers

Thermoplastic Crystalline Polymers: Have a relatively sharp melting point. Have an ordered arrangement of molecule chains. Generally require higher temperatures to flow well when compared to Amorphous. Reinforcement with fibers increases the load-bearing capabilities considerably. Shrink more than Amorphous, causing a greater tendency for deformation. Fiber reinforcement significantly decreases deformation. Usually produce opaque parts due to their molecular structure.

Thermoplastic Amorphous Polymers: Have no true melting point and soften gradually. Have a random orientation of molecules; chains can lie in any direction. Do not flow as easily in a mold as Crystalline Polymers. Shrink less than Crystalline Polymers. Generally yield transparent, water-clear parts.

Thermosetting Plastic ◦

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Also known as thermoset Is a prepolymer material that cures irreversibly made up of lines of molecules which are heavily cross-linked.

Curing: Heat (above 200 °C) Chemical reaction Suitable radiation ◦

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Thermosetting Plastic Curing process: transforms the resin into a plastic or rubber by a cross-linking process. Energy and/or catalysts are added that cause the molecular chains to react at chemically active sites Results to a rigid, 3-D structure. Yields a molecule with a larger molecular weight, resulting in a material with a higher melting point.

Thermosetting Plastic Properties: ◦

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Generally stronger than thermoplastic Suited to high temperature applications Good chemical resistance More brittle Not recyclable

Classifications of Plastics

PVC

Polyethylene Terephthalate

(PET) The most common thermoplastic polymer

Used in fibers for clothing, container for liquids and foods Inexpensive, lightweight, and easy to recycle

May exist as an amorphous or as a semi-crystalline polymer


(PET) ◦

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Softdrink, water, mouthwash bottles Peanut butter containers Salad dressing and vegetable oil container


(PET) Condensation Polymerization: esterification


(PET) Properties: Stiffness and strength Resilient to deformation Naturally colourless Lightweight Fair moisture barrier ◦ ◦

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Polyethylene ◦

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is a thermoplastic polymer consisting of long hydrocarbon chains. Simplest polymer Addition polymerization of ethylene CH 2= CH2

Variation: ◦ ◦

High Density Polyethylene (HDPE) Low Density Polyethylene (LDPE)

High Density Polyethylene (HDPE) ◦

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Catalyzed by organometallic compounds at moderate pressure (15 to 30 atm) Polymer chains are in great length Linear molecules Crystalline structure

High Density Polyethylene (HDPE) Found in: ◦

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Milk jugs Juice bottles Bleach, detergent, and household cleaners Shampoo bottles Trash and shopping bags

High Density Polyethylene (HDPE) Properties: Strong Opaque Naturally white in color Can withstand higher temp (above 100 °C) Carries a low risk of leaching Rigid Good chemical resistance

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Low Density Polyethylene (LDPE) ◦

Prepared under very high pressures (about 350 MPa) and high temperatures (about 350°C)

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Uses oxygen as initiator

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Yields a hydrocarbon chains with side short and long side branches

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Branches hinders the closely packing of molecules

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Amorphous structure

Low Density Polyethylene (LDPE)

Found in: ◦ ◦

Squeezable bottles Bread, frozen food, dry cleaning and shopping bags

Low Density Polyethylene (LDPE) Properties: Translucent Lightweight Flexible Less strong Lower melting point (75°C) Less chemical resistance

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Polyvinyl Chloride ◦

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Third most used kind of plastic Vinyl Chloride monomer is produced by combining ethylene with Chlorine Addition polymerization of monomers to PVC Amorphous structure

Polyvinyl Chloride Found in: ◦ ◦

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Window cleaner and detergent bottles Shampoo bottles Wire jacketing piping

Polyvinyl Chloride Properties: Fire retarding properties Ignition temperature of 455°C Chemically stable Resistant to oxidation (durable) Chemical resistant to almost all chemicals except for aromatics Flexible physical properties depending on additives Not safe with food use

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Polypropylene ◦ ◦

Addition polymerization of propylene One of the most versatile thermoplastic available commercially

Polypropylene Found in: Yogurt containers Syrup bottles Ketchup bottles Caps Straws Medicine bottles

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Polypropylene Properties: Stronger Stiffer Harder High melting point (170°C) Prone to oxidation

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Polystyrene ◦

Is a synthetic aromatic polymer

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Can be solid or foamed

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Formerly foamed with chlorofluorocarbon

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Addition polymerization of styrene

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Long chain hydrocarbon where alternating carbon center are attached to phenyl group

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crystalline

Polystyrene Found in: ◦ ◦

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Disposable plates and cups Meat trays Egg Cartons Carry out containers CD cases

Polystyrene Properties: ◦ ◦

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Solid PS is transparent Hard and brittle High gas permeability and good water vapor transmission Chemical resistant to acid and bases Good insulator

PLASTICS MANUFACTURING PASCU AL, JOHN RYAN TEODORO, AREEYA KYRA

RAW MATERIALS Resins Natural Resins Synthetic Resins ◦

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Additives Plasticizers Fillers Stabilizers Pigments and Dyes Blowing Agents Catalysts Accelerators Fire-retardants Anti-oxidants ◦

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Resins -are group of sticky, liquid, organic substances that usually hardens into brittle, amorphous, solid substances upon exposure to air -Insoluble in water, soluble in ether, alcohol, and other solvents -Derived from plants or vegetable matter - Oils from seeds - Starch derivatives

-Three classifications: - Hard Resins - Oleoresins - Gum Resins

Resins Hard Resins -hard, brittle, odorless, and tasteless resins that exhibit a glasslike fracture -Ex. Amber, copals, sandarac Oleoresins -obtained by distillation of oleoresin turpentine, which is a stick, amorphous semisolids that contain essential oils. - Ex. Balsam, Dragon’s Blood, Copaiba.

Gum Resins -Mixtures of both true gums and resins - Occur naturally as a form of “tears” on plants and trees

Resins Petrochemical Resins (synthetic) -Derived from oil, coal, and natural gas (crude oil) - Distillation of Crude oil to produce Naphtha - Naphtha cracking - breaking down of naphtha into smaller molecules - Usually in the form or pellets and granules

Distillation of Crude Oil

Naphtha Cracking

Additives -are ingredients added to the resin to produce a more stable plastic -are often used in plastics to produce some desired characteristics

Plasticizer -Plasticizer is the most important additive. -It is an organic liquid chosen to increase flexibility of the plastic.

Additives Filler -Fillers or extenders are added usually to thermosetting plastics to make them less brittle and to reinforce mechanical strength.

Pigments and Dyes -Pigments and dyes are added to give color to the plastic.

Additives Stabilizers -To counteract decomposition during manufacture

Blowing Agents -Commonly found in foamed plastics wherein self-generated or external heat converts blowing agents into gas bubbles expanding the resins into foam plastics

Catalysts -A catalyst, either a chemical or simply applied heat, helps to start the chemical reaction of polymerization

Additives Fire-retardants -Fire-retardants are added to the mixture to produce fire-retarding grades of plastics.

Anti-oxidants -The effect of oxygen on some plastics during manufacture can cause degradation that is why anti-oxidants are incorporated to the process.

POLYMER SYNTHESIS Polymerization -is the process of building up continuous molecular chains from individual identical monomer units

Two main methods: -Addition Polymerization -Condensation Polymerization

Addition Polymerization -Occurs when an unsaturated monomer molecule opens a double/triple bond to free a valence -Head to tail linking of monomers -Produces thermoplastics such as polyethylene, polypropylene, and polystyrene

Condensation Polymerization -is the process linking up monomer molecules of different compounds that can result with the loss of some simple molecules like water or HCl -produces both thermoplastics and thermosetting plastics such as polyesters and nylon.

Thermoplastic and Thermoset Processing Methods Extrusion

Extrusion Blow Molding

Calendering

Rotational Molding

Film Blowing

Compression Molding

Injection Molding

Casting

Blow molding

Thermoforming

Expanded Bead Blowing

Extrusion Plastic material as granules, pellets, or powder, is first loaded into a hopper and then fed into a long heated chamber . The plastic is melted by the mechanical work of the screw and the heat from the extruder wall. At the end of the heated chamber, the molten plastic is forced out through a small o pening called a die to form the shape of the finished product. As the plastic is extruded from the die, it is fed onto a conveyor belt for cooling or onto rollers for cooling or by immersion in water for cooling.

Extrusion

Calendering An extension of film extrusion. The still warm extrudate is chilled on polished, cold rolls to create sheet. The thickness is well maintained and surface made smooth by the polished rollers. Calendering is used for high output and the ability to deal with low melt strength.

Calendering

Film Blowing This process continuously extrudes vertically a ring of semi-molten polymer in an upward direction. A bubble of air is maintained that stretches the plastic axially and radially into a tube many times the diameter of the ring. The diameter of the tube depends on the plastic being processed and the processing conditions. The tube is cooled by air and is nipped and wound continuously as a flattened tube. The tube can be processed to form saleable bags

Film Blowing

Injection Molding This process can produce intricate three-dimensional parts of high quality and great reproducibility. It is predominately used for thermoplastics but some thermosets and elastomers are also processed by injection molding. In injection molding plastic material is fed into a hopper, which feeds into an extruder. An extruder screw pushes the plastic through the heating chamber in which the material is then melted. At the end of the extruder the molten plastic is forced at high pressure into a clo sed cold mold. The high pressure is needed to be sure the mold is completely filled. Once the plastic cools to a solid, the mold opens and the finished product is ejected.

Injection Molding

Blow Molding Blow molding is a simple process where compressed air is introduced underneath a warmed sheet of thermoplastic material forcing the material into a mold cavity, or allowing it to expand freely into the shape of a hemisphere.

Blow Molding

Expanded Bead Blowing This process begins with a measured volume of beads of plastic being placed into a mold. The beads contain a blowing agent or gas, usually pentane, dissolved in the plastic. The closed mold is heated to soften the plastic and the gas expands or blowing agent generates gas. The result is fused closed cell structure of foamed plastic that conforms to a shape, such as expanded polystyrene cups.

Expanded Bead Blowing

Extrusion Blow Molding This is a combination of extrusion and blow moulding Used where the article to be made has a narrow neck, such as a bottle. The plastic material is first extruded as a tube shape into an open die. The die is then closed to seal the ends of the tube and air is blown in forcing the plastic tube to take up the shape of the die cavity.

Extrusion Blow Molding

Rotational Molding Consists of a mold mounted on a machine capable of rotating on two axes simultaneously. Solid or liquid resin is placed within the mold and heat is applied. Rotation distributes the plastic into a uniform coating on the inside of the mold then the mold is cooled until the plastic part cools and hardens. This process is used to make hollow configurations.

Rotational Molding

Compression Molding This process has a prepared volume of plastic placed into a mold cavity A second mold or plug is applied to squeeze the plastic into the desired shape.

Compression Molding

Casting This process is the low pressure, often just pouring, addition of liquid resins to a mold. Catalyzed thermoset plastics can be formed into intricate shapes by casting.

Casting

Thermoforming Films of thermoplastic are heated to soften the film Then the soft film is pulled by vacuum or pushed by pressure to conform to a mold or pressed with a plug into a mold. Parts are thermoformed either from cut pieces for thick sheet or from rolls of thin sheet. The finished parts are cut from the sheet and the scrap sheet material recycled for manufacture of new sheet.

Thermoforming

Rigid Plastic Packaging ESCALANTE, JOHN

PET Bottles Polyethylene terephthalate is used as a raw material for making packaging materials such as bottles and containers for packaging a wide range of food products and other consumer goods. Examples include soft drinks, alcoholic beverages, detergents, cosmetics, pharmaceutical products and edible oils. PET is one of the most common consumer plastics used.

PET Bottles Advantages Much cheaper than other alternatives Lightweight Recyclable

PET Bottles Recycling When the PET bottles are returned to an authorized redemption center, or to the original seller in some jurisdictions, the deposit is partly o r fully refunded to the redeemer. In both cases the collected post-consumer PET is taken to recycling centers known as materials recovery facilities (MRF) where it is sorted and separated from other materials such as metal, objects made out of other rigid plastics such as PVC, HDPE, polypropylene, flexible plastics such as those used for bags (generally low density polyethylene), drink cartons, glass, and anything else which is not made out of PET.

PET Bottles

HDPE Packaging High density polyethylene (HDPE) was first developed for packaging as a film before being introduced as a bottle for milk in 1964. Its use for packaging has increased because of its low cost, flexibility, durability, ability to withstand the sterilizing process, and resistance to many chemicals. As a food packaging, HDPE is most commonly associated with milk, oil, and juice bottles. Non-food packaging uses include supermarket bags, cleaning product containers, motor oil containers, agricultural films and chemical containers, paper bag liners, bags, crates, drums, and pails.

HDPE Packaging

Plastic Pallets These are HDPE plastic molds used mainly for storage and transportation of goods. Plastic pallets can be made using virgin or recycled resin.

Plastic Pallets - Stackable pallets Stackable pallets are pallets that include bottom runners or picture frame bottoms, allowing the pallets to sit safely on top of each other when the pallets are empty. Stackable pallets allow for the safe double stacking of multiple pallets with product on them during the shipping process. Since they have a consistent bottom deck, these pallets allow for a very steady platform.

Plastic Pallets - Stackable pallets Although there are many benefits for their use, it should be noted that empty stackable pallets can take up a lot of space in storage. In addition, it should be taken into consideration that the shipping process to the manufacturer for the first use or on a back haul to the shipper can result in higher costs. Since stackable pallets are generally a very durable style of pallet, t hey are most often considered for use in a closed loop or returnable type of environment.

Plastic Pallets - Rackable pallets Rackable pallets - Rackable pallets are pallets that include bottom runners or picture frame bottoms, allowing for the pallets to sit safely on top of a rack. Rackable plastic pallets allow for storing the unit load above the floor, ultimately saving space. The bottom deck of a rackable pallet can consist of many different configurations. These configuration variations include:

Three-runner Picture frame Picture frame with a crossbar in the center of the base

Plastic Pallets - Rackable pallets Rackable pallets are usually “heavy duty” in nature due to their load capacities and weigh more due to the additional structure on the underside of the pallet. As a result of this increased structure and stability, rackable plastic pallets are also stronger pallets.

Plastic Pallets - Nestable pallets Nestable pallets - An alternative to a stackable pallet is a nestable pallet. Nestable pallets fit together when empty and reduce the amount of space needed for storage.

Plastic Crates/Baskets/Bins Plastic Crates/Baskets/Bins – a container used for storage or shipping of goods

Plastic Crates/Baskets/Bins Collapsible Crates Collapsible Crate Cratess - Collapsible plastic crate were originally developed for the automotive industry industry years ago to carry Original equipment manufacturer (OEM) parts to the assembly lines. These crates are collapsible in order to save on space in both the warehouse or in transit. They include access doors for easy accessibility to any of your parts or other materials.

Plastic Crates/Baskets/Bins Rotomolded Plastic Bins Rotomolded Plastic Bins - rotomolded plastic bins were originally designed for seafood, meat, poultry, and other food processing environments. Now, they are used in many other different applications such as recycling and bulk storage. Rotomolded bins are the toughest plastic bins on the market making it economically viable for customers.

Plastic Crates/Baskets/Bins Plastic Crates for Agriculture Plastic Crates for Agriculture - They were developed for harvesting, storage, cooling, and transportation of produce from the field to the packaging shed. They are available in different sizes depending on the produce that you are harvesting.

Plastic Crates/Baskets/Bins Plastic Hopper Bins Plastic hopper bins are extremely popular in areas of processing products in bulk such as: nuts, grains, seeds, resins etc. They are reusable and designed to be stacked and lifted by a forklift. Plastic hopper bins have been recognized for their durability and ease of sanitation.

Plastic Crates/Baskets/Bins Attached lid containers Attached lid containers - Attached lid containers are the workhorse of the distribution industry. These containers are used widely in retail distribution to ship small packaging to and from distribution centers and stores. The attached lid containers can nest when the lids are opened making them efficient for return freight.

Plastic Crates/Baskets/Bins - Hand held plastic crates Hand held plastic crates - are high quality stackable/nestable handheld containers that can be used in supermarkets or your home. Hand held plastic crates - are high quality stackable/nestable handheld containers that can be used in supermarkets or your home.

Plastic Liquid Containers Plastic liquid containers – are containers used as an intermediate or final packaging for products/materials in liquid form.

Plastic Liquid Containers - Pails Pails - this round, open-head pails made from injection molding technology, are engineered to satisfy the stringent requirements of many industries such a s chemicals, dairy, cleaning, and food processing.

Plastic Liquid Containers - Drums Drums - Made from high-density polyethylene, these injection-molded plastic drums are extremely strong and rigid allowing for easy handling and a low shipping cost.

Flexible Plastic Packaging COSTALES, ELIJA H

Flexible Plastic Packaging Flexible plastic packaging is a major group of materials that includes plastic films that can be used to make labels, wrappings, sacks, packs, pouches and sealed or unsealed bags.

Flexible Plastic Packaging Ability to protect foods and extend the shelf-life;

Tough and durable to withstand rough handling during transport and distribution; Handling convenience for both processors and customers, Adds very little weight to the product which reduces transport costs ;

Flexible Plastic Packaging •

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Easily printed on as labels to inform customers about the product Fit closely around the product which reduces space for transport

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Attractive appearance to the mass consumers;

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Mostly inert and unreactive

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Good barrier properties to moisture and air.

Flexible Plastic Packaging Barrier Properties Barrier properties are the resistance that a package has to moisture, air, light, micro-organisms, puncturing, etc. It gives an indication of the amount of protection that is given to a food by a particular packaging material.

Two Factors: •

Water Vapor Transmission Rate (WVTR)

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Oxygen Transmission Rate (OTR)

Flexible Plastic Packaging The polymers that are most commonly used for flexible plastic packaging are low density polyethylene (LDPE) and linear low density polyethylene (LLDPE).

Polyethylene (PE) films •

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It is the oldest thermoplastic film It is the cheapest and most used plastic films used for food packaging; Excellent heat sealability It allows moisture and air to pass through at a higher rate than many films.

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It has very low barrier properties

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It has poor resistance to oils

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Susceptible to damage by sunlight which leads brittleness and opaqueness It is used as single layer to pack products requiring low protection like: Frozen vegetables, Frozen Fish

Low Density Polyethylene (LDPE) films

Low Density Polyethylene (LDPE) films •

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Poor barrier properties to moisture and air; Poor resistance to puncturing, although it does not tear easily; Does not protect foods against mechanical damage, thus, require outer cartons or boxes for transport and distribution;

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It has low melting point which makes it easily heat sealable.

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Inert.

However, the plasticizers used to make the film flexible can be absorbed by fats in foods and may be linked to nerve damage to eyes and development of cancers . LDPE should not therefore be used to package fatty foods (including cooking oils, butter, cheese or biscuits)

Low Density Polyethylene (LDPE) films

High Density Polyethylene (HDPE) films •

Thick Polyethylene ;

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Good barrier against moisture, air and odours;

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Stronger, less flexible and more brittle than LDPE;

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It has a higher softening temperature (121°C);

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It is a strong film that gives a strong heat seal

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Ability to withstand puncturing, tearing and stretching;

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Use as sacks for rough handling;

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However, it is more slippery than jute, paper or other natural fibres Poor resistance to sunlight

Polypropylene (PP) films • •

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A clear, glossy, transparent and sparkling film; It is strong, heat sealable and withstands puncturing and tearing. It does not stretch as much as Polythene It has good barrier properties to moisture, air and odours It is not damaged by sunlight nor affected by drying out by low temperatures. Suitable for larger heavy duty packs or as stronger packages ( e.g. pasta, pulses, dried fruits and cereal products)

Polypropylene (PP) films • • •

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There is no movement of plasticizers into fatty foods unlike polyethylene. It has a higher sealing temperature than polyethylene Because of its attractive, glossy appearance and better barrier properties, it is replacing polyethylene in many applications . However it is more expensive than polythene. Polypropylene is also woven into sacks for bulk transport of both fresh and processed foods. PP sacks are very tough and resist puncturing, tearing and stretching. Allow moisture and air to pass through the weave (in contrast to HDPE sacks) and they are therefore more useful for fresh produce or for foods that do not require protection against these factors.

Cast Polypropylene (CPP) films • • •

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Better machinability properties than PE Thickness range between 20μ to 40μ It is transparent with a more crystal-like view than PE It has very low protection barrier Better printability properties than PE, but still must be printed in flexo Not used as laminating layer

Bi-Oriented Polypropylene (BOPP) films • • •

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It is the most used thermoplastic film Thickness range: 15μ to 40μ (most between 20μ-30μ) It can be : transparent, white, opaque, metallized, lacquered, pearly It has very low heat sealing properties Better barrier properties than PE or CPP Excellent printability in flexo or rotogravure Used as simple- or laminated layer Used in snacks, pasta, dish was powders, biscuits, frozen food

Flexible Plastic Packaging Innovations Metalized Films -application of a layer of aluminum to a polymer’s surface -Lower cost and tare weight makes metalized films a popular choice in the food and confectionary fields -resistant to both water and oxygen transmission as well as providing a metallic and glossy appearance

Based on Erin Hoppe’s “Flexible Packaging: Innovations and Developments” University of Wisconsin-Stout 2009

Flexible Plastic Packaging Innovations Smart packaging employed in plastic films:

Active packaging

Intelligent packaging


Flexible Plastic Packaging Innovations Active Packaging Films -employs moisture absorbers, temperature control packaging, preservative releasers, oxygen‐scavenging, and carbon dioxide absorbers -controls and reacts to outside influences that occur inside of the package: light water, oxygen, microbial and chemical contamination


Flexible Plastic Packaging Innovations Modified Atmosphere Packaging Films -it modifies the internal environment of the package; slows down natural deterioration; preserves the product’s fresh state for a longer period of time -Controls the transmission rate of oxygen and carbon dioxide as well as the quantity of oxygen both inside and outside of the package

Based on Erin Hoppe’s “Flexible Packaging: Innovations and Developments”

Flexible Plastic Packaging Innovations Intelligentt Packaging Films Intelligen -involves a ‘smart’ material that is capable of detecting a change in its environmentt through any combination of indicators, sensors, and processors environmen -an automatic response takes place resulting in neither the product, package, or consumer being compromised.


Flexible Plastic Packaging Innovations Intelligentt Packaging Films Intelligen Fi lms -Antimicrobial films capable of controlling the growth of microorganisms microorganisms in food -conductive polymers and the light‐emitting properties they posses -it could be possible for the film to produce advertisements or signal lights


Future Innovations for Flexible Plastics An ongoing trend in the packaging packaging market is the development development of materials which posses high‐barrier properties. There is continuing research regarding biodegradable/compostable films and the push to make them more widely available and utilized. molecules” added to polymer structure has resulted A recent application of “food‐grade flavor molecules” in the development of a film that releases odors/aromas on the inside or outside of a package (Byrne).


Plastic Packaging

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