Transparent styrene-acrylonitrile polymer compsn. - contains polystyrene and (non)uniform styrene-acrylonitrile copolymers

摘要

Transparent polymer material consists of polystyrene (I), a non-uniform copolymer (II) of styrene (St) and acrylonitrile (AN) and a St-AN copolymer (III). (II) is prepd. by charging a polymerisation zone with a prim. charge (A) of St and/or AN from prim. source(s) so that the monomer concn. in the charge varies continuously and simultaneously adding different sec. charge(s) of St and/or AN to the prim. source from sec. source(s) to effect this variation. Polymerisation is carried out continuously under monomer-starved conditions. A polymer alloy of (I) and A St-AN copolymer is obtd. with better transparency and clarity, due to the better compatability than a physical mixt. of (I) and a St-AN copolymer. The polymer alloy gives a very high transparency when mixed with (I), A St-AN copolymer or any polymer of these, regardless of the method of mfr.