Biodegradable vinyl] ester copolymers for packaging film etc. - comprises vinyl] acetate etc. cyclic ketene acetal, esp. 2-methylene-1,3-dioxepane

摘要

Copolymers (I) of mol.wt. above 50,000 are based on vinyl ester(s) of (un)branched 1-18C alkane-carboxylic acids (II) and 0.1-40 wt.% (w.r.t. copolymer) cyclic ketene acetal(s), i.e. 2-methylene-1,3-dioxepane (III), 2-methylene-1,3-dioxolane or 2-methylene-1,3-dioxan. Prodn. of (I) is by copolymerisation in presence of 0.005-0.5 mole% radical initiators (w.r.t. comonomer phase). Copolymers have high mol.wt. and the lowest possible ketene acetal comonomer content. Pref. (I) have mol.wt. of at least 200,000 and are derived from 85-98 wt.% vinyl acetate (VA) and 2-15 wt.% (III) or 70-95 wt.% VA, 5-25 wt.% ethylene and/or dialkyl maleate or fumarate and 2-15 wt.% (III), or 50-70 wt.% VA, 10-30 wt.% vinyl alpha-branched carboxylate, 5-25 wt.% ethylene and 2-15% wt.% (III), or 50-70 wt.% VA, 1-30 wt.% acrylate ester (esp. n-butyl or 2-ethylhexyl acrylate), 5-25 wt.% ethylene and 2-15 wt.% (III). (I) are pref. prepd. by bulk, soln., emulsion or suspension copolymerisation. USE/ADVANTAGE - Biodegradable vinyl ester copolymers (I) are used for the prodn. of film for packaging or mulching, etc., as binders for non-woven, esp. cellulose-based, fabrics and in coating materials.