process for the production schlagfester pfropfmischpolymerisate from styrene or vinyltoluol and synthetic rubber

摘要

Impact-resistant graft copolymers of styrene or vinyl toluene (I) with synthetic rubber (II) are prepd by dissolving (II) in (I) at is not 80 degrees C adding softening agent (III) and mol. wt regulator (IV) and heating at 85-125 degrees C to 25-40% conversion of (I), suspending 1 wt pt. of this prepolymer in 0.3-0.6 wt. pts water contg. 0.15-1.5 wt. % Ca3(PO4)2 and 0.003-0.02 wt. % wetting agent (V), adding 0.15- 0.35 wt. % CaCO3 whilst heating to 90 degrees C, and continuing heating in stages to higher temps to complete the polymerisation. (II) is e.g. polybutadiene, polyisoprene, polybutadiene/styrene (III) is vaseline oil or butyl stearate. (IV) is e.g. laurylmercaptan. (V) is Na salt 8-18C alkylsulphate. Use of Ca3 (PO4)2, (V) and CaCO3 as stabilising system for the oil-in-water type of suspension formed for final polymerisation is novel. The copolymers are used for moulded components used in transport industry, housing and parts of radio and television receivers, refrigerator parts, packagings for fruit and foodstuffs. The special stabiliser system permits higher polymer, water proportions during polymerisation hence higher mfg. efficiency, greater yields from plant units, lower waste water and associated contamination problems.