| 摘要 |
This invention is directed to a process for the preparation of vinyl chloride homopolymers, copolymers thereof with other monomers or graft copolymers containing at least 50% by weight of vinyl chloride units. The monomer or monomer mixture is polymerized in aqueous dispersion in the presence of a radical-forming catalyst in a reactor. The inner walls of the reactor and other portions thereof where polymer deposits may form are coated with a coating containing a compound of the formula I (I) wherein R1 is hydrogen, a hydrocarbon radical of aliphatic character having from 1 to 12 carbon atoms, an acyl having from 2 to 8 carbon atoms, R2 is R1 or R2 and R1 together are alkylidene or aralkylidene, R3 is hydrogen or a hydrocarbon radical of aliphatic character having from 1 to 12 carbon atoms; or at least one of the radicals, R1, R2 or R3 being hydrogen, R4 is R3, furthermore alkoxy having from 1 to 6 carbon atoms, hydroxyl, halogen, amino, (di)alkylamino having from 1 to 12 carbon atoms, carboxyl, sulfoxyl (=SO3H); R5 is R4; or R4 and R5 together are an aromatic ring. |
