| 摘要 |
<p>A CONTINUOUS BULK POLYMERISATION PROCESS Copolymers of A 22 to 96 mol-% of styrene and/or .alpha.-methyl styrene, B 0 to 78 mol-% of at least one monoolefinically unsaturated monomer containing nitrile groups, and C 0 to 50 mol-% of at least one monoolefinically unsaturated monomer different from A or B are obtained by continuous bulk polymerisation in a homogeneous liquid phase, in several process stages, in one or more different temperature ranges and in the presence of one or more initiators with different dissociation times in each temperature range and under pressures of from 1 to 20 bars. In first stage the monomers are copolymerized with backmixing up to a conversion of from 10 - 60 mol-% in an ideally mixed tank reactor and then after optionally additional addition of further parts of monomers copolymerization is continued with backmixing in a completely flooded, selfcleaning polymerization kneader up to a residual monomer content of from 10-50 mol-%. Residual monomers are continuously removed from the copolymer up to a content of less than 0.5% by weight based on the copolymer. The process according to the invention provides uniform, compatible, homogeneous products which are free from gel-like particles and which combine improved transparency with greater dimensional stability under heat and better mechanical properties together with improved processibility.</p> |
