| 摘要 |
548,264. Vinyl polymerization products. DU PONT DE NEMOURS & CO., E. I. March 31, 1941, No. 4289. Convention date, March 30, 1940. [Class 2 (iii)] Moulding compositions having an average molecular weight between 15,000 and 32,000 are prepared by forming an interpolymer of 100 parts .by weight of methyl methacrylate with 5 to 25 parts of one or more of the following, styrene, vinyl acetate and methyl acrylate, having an appropriate molecular weight between 34,000 and 100,000 and malaxating the interpolymer, preferably at an elevated temperature, until the molecular weight of the interpolymer is reduced to the desired figure. The malaxating may be conducted upon mixing rolls running at equal or unequal speeds, or in a masticator mixer or screw stuffer. Examples are given of products obtained by malaxating interpolymers obtained by polymerizing, according to the process described in Specification 427,494, methyl methacrylate in admixture with styrene, vinyl acetate, methyl acrylate, a mixture of styrene and vinyl acetate, or a mixture of vinyl acetate and methyl acrylate, in the presence of a mould lubricant, using benzoyl peroxide as a catalyst. Specification 480,592 is referred to. |
