| 摘要 |
Ethylene and vinyl acetate and/or vinyl propionate are copolymerized at a pressure of at least 10 atmospheres, at between 10 and 200 DEG C., in the presence of a free-radical catalyst, in a homogenous liquid phase containing predominantly t-butyl alcohol. The t-butyl alcohol is present in an amount 3 to 10 times that of the vinyl ester and the ethylene and esters are used in a proportion from 2:1 to 20:1, to produce copolymers in which the vinyl ester is present in an amount not exceeding 35% by weight. Water may be present in an amount to maintain the homogenous phase and to keep the medium at a preferred pH of 3 to 7. Catalysts specified are, acetyl, benzoyl, lauroyl, dichlorobenzoyl peroxides, peroxydicarbonates, and a ,a 1-azodiisobutyric acid nitrile. Films, foils and moulded articles with good transparency and pliability may be formed from the products. |
