Barrier packaging protects products from infiltration or in some cases, exfiltration (the passing out from the container) of contaminants, of flavor, color, odor, etc., as well as preserving the contents. Barrier resins are polymers that are used in packaging to provide a barrier to some unwanted intrusion in or out of the package. Barrier resins block passage of several important substances, including oxygen, moisture, odors, flavors and others. Plastic barrier packaging has shown significant growth since the discovery and development of the first synthetic specialty barrier resin, polyvinylidene chloride in the 1950s and 1960s. The commercialization of ethylene vinyl alcohol (EVOH) came a bit later, in the 1970s. The barrier properties that are very critical are: Oxygen, Carbon Dioxide and Moisture. Unfortunately, sunlight and store lighting cause color fading, vitamin loss, and generally compromise the most carefully designed product and can damage branding image and credibility by low taste or poor visual appearance. For obvious economic reasons, the food, detergent and cosmetics industries constantly search for solutions to extend the shelf life of their products.

As per a new market research report from Business Communications, the demand of barrier resin in USA in 2004 was about 2.7 KT and is expected to grow at 8% to reach about 3.9 KT by 2009. There are 3 basic applications markets of barrier resin. The largest is food and beverage packaging, which accounts for more than 90% of the U.S. market. Other smaller but important markets include chemical/industrial products packaging (including automotive gasoline tanks) and healthcare products packaging such as blister packaging. There are essentially 3 different types of products in the category of barrier resin:

1. Barrier resin
2. Permeable film
3. Tie layer resin

• Ethylene-vinyl alcohol (EVOH) copolymers, the highest oxygen barrier resins are now commercially produced and most used in the U.S. for food packaging.
• PCTFE, the fluoropolymer polychlorotrifluoroethylene, the highest moisture or water vapor barrier resin is mostly used for pharmaceutical blister packaging (PBP) for drugs, which are very moisture sensitive.
• Nitrile resins, copolymers of acrylonitrile (AN) with methyl acrylate (MA) are used in food, chemical/industrial and healthcare packaging
• Polyamide (nylon) barrier resins, primarily oriented nylon 6, is mostly used in food packaging, and is also used in chemical/industrial and healthcare product packaging.
• Thermoplastic polyesters, primarily PET is by far the largest market since we include the use of PET as a carbon dioxide barrier resin in beverage bottles. This market is expected to continue to constitute more than 90% of the barrier resin market as it grows at an AAGR of 8.3% through the forecast period.

Current barrier packaging plastics are good, but problems that restrict their use or hinder their growth remain in many applications. These include:

• High Cost:
  Cost of barrier resins is almost always higher than the cost of a simple monolayer plastic package of LDPE or LLDPE.
• Susceptibility to contamination or degradation especially by moisture:
  EVOH is the best example of this problem, since its hydroxyl groups give it good barrier qualities but also make it susceptible to hydrolysis. As a result, EVOH only can be used as an inner layer in a MLS.
• Recylcing or Disposal problems:
  Since most barrier packaging contains more than one type of plastic, recycled is difficult.
• Challenges from competing materials:
  Silicon oxide glass coatings can provide a superior barrier.