| 摘要 |
PURPOSE:To provide the title saponified copolymer having excellent electrical characteristic, resistance to water and heat, etc. and good gas barrier properties in a high-temperature atmosphere, by specifying the ash content and the alkali metal content of an ethylene/vinyl acetate copolymer. CONSTITUTION:A saponified ethylene/vinyl acetate copolymer having an ethylene content of 2-60mol% and a degree of saponification of the vinyl acetate moiety of not lower than 95% is washed with an aq. soln. of a weak said having a pKa (25 deg.C) of not lower than 3.5 (e.g., acetic acid) to remove salts contg. ash and alkali metal components. The copolymer is then washed with an aq. soln. of a strong acid having a pKa (25 deg.C) of not higher than 2.5 (e.g., oxalic acid), washed with water and dried to obtain a saponified ethylene/vinyl acetate copolymer having an ash content of not higher than 20ppm and an alkali metal content of not higher than 5ppm. |
