Non-crosslinked chloroprene polymers - prepd. in presence of xanthic disulphides contg cyclic substituents and blended with crosslinked chloroprene polymers

摘要

Vulcanisable chloroprene polymers which can be worked up easily are prepd. by polymsg (A) 60-100 wt. pts. chloroprene and 40-0 wt. pts of a 4-8C diene, H atoms of which may be replaced entirely or partly by halogen, and/or of an alpha-olefin, in the presence of 0.05-30 wt.pts. of a xanthic disulphide of formula: ROSCSSCSOR (I) (where R is X is H, alkyl, aryl, aralkyl, or halogen; n is 1 to 20) and mixing with (B) a cross-linked, benzene-insoluble chloroprene- homo- or copolymer of 80-100 wt. pts. chloroprene and 20-0 wt. pts. of a divinyl cpd. and/or an alpha-olefin, the wt. ratio of (A):(B) is 20:1 to 1:20 (1:1 to 7:1). Vulcanisates of mixts. contg. (A) have improved tear-strength and higher modulus compared to vulcanisates of mixts. contg. non-cross-linked chloroprene polymers prepd. in presence of dodecyl mercaptan or dialkyl xanthic disulphides.