PROCESS FOR THE PREPARATION OF TRIOXANE COPOLYMERS

1480536 Trioxan bulk copolymerization procedure HOECHST AG 16 Dec 1974 [18 Dec 1973] 54160/74 Addition to 1444789 Heading C3P Trioxan is bulk copolymerized with up to 10% of a cyclic acetal by (a) mixing the monomers and a cationic catalyst at 62‹ to 115‹ C., (b) cooling the liquid mixture obtained sufficiently rapidly that solidification occurs without the liquid mixture becoming turbid, and (c) heating the solid mixture at 62‹ to 130‹ C. while maintaining it in the solid state, to effect polymerization, the step (b), at least, being carried out in a double-screw extruder. Preferably all three stages are carried out in different zones of a single extruder; the final step (c) may be completed in a screw conveyer. The catalyst may be diluted with gaseous or liquid diluents, while the resulting polymers may be stabilized by hydrolytic or thermal degradation and/or by the addition of stabilizers prior to use as a moulding composition. Examples refer to trioxandioxolan copolymerization in the presence of methylol as regulator and of BF 3 .Bu 2 O.