| 摘要 |
<p>Copolymers of ethylene, 30 to 80% by weight vinyl acetate and 0.02 to 0.5% by weight based on the vinyl acetate of a divinyl ester of a C2- 10 saturated aliphatic or C8- 12 aromatic dicarboxylic acid may be prepared by polymerizing the monomers in the presence of a radical addition polymerization catalyst at 10 DEG to 200 DEG C. and pressures greater than 10 atmospheres. Specified divinyl esters are divinyl oxalate, succinate, adipate, azelate, sebacate, phthalate and terephthalate, and 1 to 30 weight per cent of other monomers, e.g. monovinyl esters, monovinyl ethers, vinyl halides and N-vinyl lactams, may also be used. Specified catalysts are lauroyl, acetyl, benzoyl and dichlorobenzoyl peroxides, peroxydicarbonates and azo compounds. Polymerization is preferably effected in the presence of liquid media containing t-butanol. When the reaction medium contains water it is preferably at a pH of 3 to 7. In examples ethylene, vinyl acetate and divinyl adipate are are copolymerized in t-butanol in the presence of (1) and (2) azodiisobutyronitrile and (4) lauroyl peroxide; and (3) ethylene, vinyl acetate, vinyl 3-chloropropionate and divinyl adipate are copolymerized in t-butanol in the presence of azodiisobutyronitrile. Copolymers of ethylene, vinyl acetate and divinyl adipate are compounded with (5) furnace black, dioctyl phthalate, stearic acid, phenyl-a -naphthylamine, triallyl cyanurate, dicumyl peroxide and calcium carbonate and extruded to form profiled sealing strips for windows, and (6) silicic acid stearic acid, triallyl cyanurate, dicumyl peroxide and calcium carbonate and extruded to form tubes.</p> |
