| 摘要 |
PURPOSE:The titled saponified copolymer providing a molded article free from fish eye, etc., having improved heat stability in melt molding, by treating a saponified ethylene-vinyl acetate copolymer with a specific acid and calcium primary salt or magnesium salt of polybasic acid wherein at least one of them contains a phosphate group. CONSTITUTION:A saponified ethylene-vinyl acetate copolymer containing 20-60mol% ethylene content and >=90mol% saponification degree of vinyl acetate component is treated with (A) an acid (e.g., acetic acid, orthophosphoric acid, etc.,) containing an acid group with <=5 pka at 25 deg.C and (B) calcium primary salt or magnesium salt (e.g., calcium primary phosphate, etc.,) of a polybasic acid containing an acid group with <=3.4 pka at 25 deg.C so that the saponified copolymer is adjusted to have 0.001-0.25wt% alkali metal content, a molar ratio of the alkali metal to phosphate group of 0.1-5 and a molar ratio of calcium or magnesium to phosphate group of 0.3-1.3. At least one of the acids A and B contains phosphate group.
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