More polymers and compounds in Packaging

                                                                                         

These various thermoplastic polymers are used in the production of various packaging materials. These polymers (the ones mentioned below) generally have good resistance to alcohols, oils grease and dilute acids and alkalis. Packaging materials made using these, especially PVC, are often longer lasting and can be modified to form almost all kinds of packaging material with insulation and germ repulsing properties, especially useful for overwrap packaging of fresh foods (plastic packets, sandwich wrap etc).

Below is a description of some of the common ethylene polymers used in various forms, especially for the packaging of perishable consumer items (foodstuff and pharmaceuticals).

Acrylonitrile butadiene-styrene - Rubber (ABS)

Properties: Hard and rigid, opaque, glossy, tough, good low temp properties, low creep, very good resistance to dilute acids and alkalis, oils and greases. This type of rubber is predominantly used in other industries and has few uses in packing, being mostly used as a shock absorbent within product cases and boxes for shipping.

Polyamide or 'Nylon' (PA)

Nylon is a generic designation for a family of synthetic polymers known generically as polyamides and is one of the most commonly used polymers. It is a high barrier material to oxygen and carbon dioxide and a moderate barrier to moisture. Widely used as the barrier component in a laminate; it has poor heat sealing characteristics and is an expensive material to produce.

Some other useful properties: Rigid, translucent, tough, fatigue and creep resistant, resistant to fuels, oils, fats and most solvents, steam sterilizable, but with poor resistance to dilute acids and alcohols.

Nylon - PA is used in packaging in the form of nylon film as a starting point. Natural Nylon films are ideal for use in a variety of food packaging applications. They perform well as a vacuum bagging film for the molding of critical composite parts in the production of aircraft parts. They allow a wide range of applications including solvent recovery bags, and environmental disposal bags. They are also available in custom-sized sheets for use in a variety of shielding and overwrap applications.
Nylon films are used to produce various products like;

- Packaging pouches, clear bags and overwrap sheets.
- Pharmaceutical packaging.
- Aluminum foils.
- Packaging bags.
- Dairy packaging etc.

Polycarbonate - Caliber or Makrolon or lexan (PC)

Polycarbonates are a particular group of thermoplastic polymers. They are easily worked, molded, and thermoformed. Their interesting features (temperature resistance, impact resistance and optical properties) position them between commodity plastics and engineering plastics.

Other properties: Rigid, transparent, outstanding impact resistance (to -150° C) good weather resistance, dimensional stability, resistant to flames, good resistance to most fluids.

This material not often used as a food packaging material as it is extremely expensive to purchase. It has excellent clarity and good barrier properties and is generally used in the production of bottles and glasses for drinking.

Polyvinylchloride & Polyvinyl Dichloride – SaranWarp, ClingFilm (PVC & PVdC)

PVC is the third most widely used thermoplastic polymer after polyethylene and polypropylene.

PVC properties: Variable flexibility, clear, durable, weatherproof, flame resistant, good impact strength, good electrical insulation properties, but limited low temperature performance.

It has good barrier properties to gasses and moisture if not highly plasticized. When plasticized, it is a poor barrier material and is used to over-wrap fresh produce. It can be thermoformed and has good heat sealing characteristics. In the past it was widely used to contain bottled water.

There are environmental concerns associated with PVC; consequently its use has decreased in recent years. Furthermore, migration of the vinyl chloride monomer from the packaging material into the packaged food has safety implications which are being investigated.

PVC Packaging: Several simple properties have made PVC invaluable as one of the key plastics used in modern day packaging to protect and preserve products. In the EU, ½ million tons of PVC is used to produce rigid and flexible (cling) film for packaging of foodstuff and closures.

- It is flexible, light, cost-effective, transparent, tough and safe.

- PVC protects against contamination by helping to prevent the spread of germs during manufacture, distribution and display, particularly in the form of cling film.

- PVC film is used in the production of;

- Blisters and presentation trays
- Toiletries
- Toothpaste Tubes
- Salad Packs
- Bottle Sleevings
- Mobile Phone Accessories
- Cash Containers



PVdC (saran wrap): The barrier properties depend on the degree of plasticizer added during manufacture. It is widely used to over-wrap food.

Butadiene (Styrene- Butadiene Rubber (SBR)

This material is an elastomeric copolymer consisting of styrene and butadiene. It has good abrasion resistance and good aging stability when protected by additives.

Major properties: Elastic, translucent, high resilience, good abrasion resistance and low temperature properties.

SBR is generally used in the production of car tires, shoe soles and gaskets, however, it is also used to make sealing caps for bottles and jar-containers as well being used in shock absorbent packaging.

About the author:
ABC Packaging Direct works with you to understand your packaging needs and develop specialty packaging solutions including food packaging, thermoformed plastic trays, stand up pouches, low melt bags, autoclave bags, plastic valve bags and VCI bags.

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