ABS continuous prodn. by bulk graft polymerisation - after preheating under pressure to give specified monomer conversion and increase rubber effectiveness

Continuous prodn. of ABS by (graft) polymerisation of a soln. of butadiene rubber (I) in a mixt. of styrene (II) and acrylonitrile (III) monomers is carried out at 80-200 degrees C., followed by removal of volatiles from the ABS melt at 200-230 degrees C. and 10-20 torr. The novelty is that the (I) soln. is heated, before polymerisation, at 60-100 degrees C. and a pressure exceeding the (III) vapour pressure at the temp. used until the degree of conversion of the monomers attained is 3-6%. ABS is widely used for the mfr. of pts. and housings for radio and TV receivers, telephone equipment, typewriters and calculators, refrigerator linings, vehicles pts., tubes, etc. The prod. has the required physical-mechanical properties and a lower copolymer content than usual, which increases its effectiveness.