| 摘要 |
PURPOSE:To obtain a packaging material having improved resistance to permeation of gases, e.g. oxygen, by preparing a molded article having a layer consisting of a specific ethylene-vinyl alchol copolymer, etc., and heat-treating the resultant molded article under specified conditions to give a plural thermal melting points. CONSTITUTION:A molded article containing a layer consisting of (A) ethylene- vinyl alcohol copolymer containing 50-75mol% vinyl alcohol and 4mol% or less preferably 1mol% or less, based on the total amount of the remaining vinyl ester and the vinyl alcohol ester, the remaining vinyl ester, or (B) a blend of the component (A) with up to 150wt% based on the component (A) an other thermoplastic polymer, e.g. polyethylene. The resultant molded article is then heat-treated at a temperaute and for a time satisfying formula I [Y3 is the heat-treating temperature ( deg.C); X is the content of vinyl alcohol (mol%) in the component (A)] and formula II [t is time (min)]. |
