Published October 2015
Ethylene–vinyl alcohol copolymer resins (EVOH) are specialty products that have superior gas barrier properties. They are often used as the internal layer in multilayer food packaging films and blow-molded rigid containers for a variety of purposes including gasoline tanks for automobiles. EVOH can be fabricated by melt processing. The barrier properties of EVOH films decrease in the presence of moisture, so coextrusion with protective polypropylene (especially biaxially oriented material), low-density polyethylene, nylons, or other moisture barrier films provides films or articles that are useful even with liquids.
In all world areas, EVOH is used predominantly in laminated gas barrier packaging films and to a lesser extent in extruded articles including blow-molded or thermoformed plastic parts, sheets and automotive gasoline tanks.
The following pie chart shows world consumption of ethylene–vinyl alcohol resins:
EVOH was first commercialized in Japan around 1972, grew at double-digit rates globally through the 1990s, then slowed to an average annual rate of 6% through 2007 and 2% during 2007–10.
The EVOH industry is an oligopoly, that is, a market with a very limited number of producers, a result of the high market entry barriers of high capital costs and the time-consuming and expensive process of product specification for food usage.
The increasing costs of raw materials manufactured from natural gas and crude oil feedstocks, such as ethylene and vinyl acetate monomer (VAM), could negatively affect the profitability of EVOH consumers; hence, demand may continue to slow from higher historical rates.