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This email address is being protected from spambots. You need JavaScript enabled to view it. holds a B.S. in Plastics Engineering from the University of Massachusetts - Lowell. He has been affiliated with the converting industry for more than 30 years...more

Common Barrier Packaging Polymers—Their Functions & Applications

Plastics for use in barrier packaging is commonplace today. The list below of common barrier polymers provides their functions and applications in tabular form for easy reference by the reader.

Hundreds of thousands of tons of polymers are used globally each year for various packaging uses. A small percentage of these are barrier polymers, which of course are used to prevent the migration of “something” into the package. That something is usually oxygen, water, and light. Sometimes the purpose is to keep something in, such as in modified atmosphere packaging, and sometimes it is to let something out, such as carbon dioxide in cheese packaging.

Below is a table of common polymers used in multilayer food packaging. It should come in handy for R&D personnel and perhaps even marketing and sales people when presenting a list of capabilities to customers.

Suggestions for follow-up articles are welcomed. If none are received shortly, the next blog will review a list of common adhesives used for lamination in packaging.

Plastic Polymer Functions in Multilayers Applications
Polyethylene (PE)

Heat-sealable food contact layer

Moisture barrier

Can be combined with gas/aroma barriers (e.g., PA, EVOH)

Breathable packaging for fresh produce (LDPE), HDPE)

Carton liners (LLDPE)

Polypropylene (PP)

Moisture barrier

To provide mechanical strength

Can be coated with heat seal coatings (PVDC, acrylate)

Can be combined with gas/aroma barriers (e.g., PVDC coatings, PA, EVOH)

Modified atmosphere packaging thermoformed containers for microwavable packaging, hot-filled packaging
Polyamide (PA)

Gas/aroma barrier

To provide mechanical strength

Heat resistance

Can be used as outside layer of a heat seal film → film will not stick to the sealing bar surface

Boil-in-bag packaging

Thermoformed packaging

Polyethylene Terephthalate (PET)

Gas/aroma barrier

Moisture barrier

To provide mechanical strength

Heat resistance

Plastic bottles for carbonated soft drinks

Meat and cheese packaging

Snack food wrapper

Boil-in-bag

Sterilizable pouches

Ovenware containers

Polystyrene (PS)

Gas permeability

Printability

Can be combined with gas/aroma barriers (coextruded or laminated) → commercially available structures: e.g., PS/PVDC/PS, PS/PVDC/PE, PS/EVOH/PE, PS/EVOH/PP

Breathable packaging for fresh produce (e.g., fresh meat packaging) printable outside layers
Ethylene Vinyl Alcohol (EVOH)

Oxygen barrier

Needs to be protected from moisture → often sandwiched (coextruded) between PE or PP, in some applications also sandwiched between PET, PA, or PS

Modified atmosphere packaging

Packing of oxygen-sensitive food

Polyvinylidene Chloride (PVDC)

Gas/aroma and/or moisture barrier

To protect the surface from scratches and abrasion

Heat-sealable food contact layer

Often copolymers of vinylidene-chloride and ester-type monomers (e.g., ethyl acrylate)

Modified atmosphere packaging applied as coating or coextruded film
Ethylene Vinyl Acetate (EVA)

Moisture barrier

Adhesion layer (tie layer) for coextrusion of polar (e,g., PA, PET-G) and non-polar (e.g., PE) or BOPP films

Modified atmosphere packaging applied as coating or coextruded film
Polycarbonate (PC)

Heat resistance

Mechanical strength

Moisture barrier

Microwavable packaging, hot-filled packaging

Modified atmosphere packaging barriers for fruit juice cartons

Polyvinylchloride (PVC)

Gas/aroma barrier

Mechanical strength

Fresh food packaging (e.g., PVC/PE films)

Modified atmosphere packaging (e.g., PVC, EVOH, PE films)

Polyethylene Naphthalate (PEN)

Gas/aroma and moisture barrier heat resistance

For hot refills, rewashing, reuse beverage bottles (e.g., beer)

Glycol modified polyethylene terephthalate (PET-G)

Heat-sealable food contact layer

Unit dose pharmaceutical

Blister packaging

Ethylene Acrylic Acid (EAA)

Extrusion coating tie layer between aluminum foil and other polymers

Heat-sealable food contact layer

Grease resistance

Chemical resistance

Food packaging applied as tie layer or heat seal layer

Ionomer

Extrusion coating tie layer between aluminum foil and other polymers

Heat-sealable food contact layer

Heat seal through fat and contaminants

Superior grease resistance

Superior chemical resistance

Food packaging applied as tie layer or heat seal layer

 

Remember, your timely suggestions for follow-up articles are welcomed by writing me at This email address is being protected from spambots. You need JavaScript enabled to view it..


 

 

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