| 摘要 |
A process for preparing in aqueous emuision an interpolymer composition have polymerized therein 86 to 92 mole percent vinylidene chloride, 14 to 8 mole percent of a comonomer mixture of methyl methacrylate and a comonomer selected from the group consisting of acrylonitrile, methacrylic acid and methacrylonitrile in a ratio of the comonomer to methyl methacrylate of from 0.5 : 1 to 2 : 1, and 0.5 to 1.0 weight percent itaconic acid, based on weight of vinylidene chloride plus comonomer mixture. The interpolymers are prepared in a three step process wherein the monomer feeding is step-wise reduced for a portion of Step III and a polymerization initiator is added at the same constant rate as in Steps I an II. The process reduces the amount of unreacted mixed monomers remaining after monomer addition is completed and the detrimental results of a large variation in polymer composition particularly from high vinylidene chloride fractions. |
