Low mol. wt. ethylene-vinyl acetate copolymers - prepd. in presence of acetaldehyde in tert butanol reaction medium

摘要

Prepn. of ethylene/vinyl acetate copolymers having mol.-wt. 500-10,000, by polymsn. of ethylene and vinyl acetate in mol. ratios 20:1-1:1 in the presence of free radical polymsn. initiators, at 10-200 degrees C and press. 10-700 bar, takes place in the presence of 0.2-5 (0.4-5)wt.% AcH, w.r.t. monomers, in a tert.-butanol reaction medium. Copolymers contg. ethylene and vinyl acetate in mol ratios 10:1-5:1, having mol. wts. 500-3,000 and limiting viscosity 0.1-0.25 dl/-g., are pref. used as additives for lowering pour point and improving filterability of mineral oil fractions, esp. of "middle distillates" having b. pts. 120-400 degrees C. Copolymers may also be used as adhesives, adhesive components, plasticisers esp. for high Cl-contg. polymers, cellulose esters and polymethacrylates. Copolymer saponification prodts. and their reaction prodts. with OH gp.-reacting cpds., e.g. isocyanate, acid anhydride or -chlorides, carbonyl cpds. and epoxides can be used for prodn. of lacquers, as adhesives and plasticisers.