Patent ID: 6225429
Filing Date: 2001-05-01
Classification: C08F

Abstract:
A process of making a vinyl caprolactam (VCL)-based terpolymer by suspension polymerization of the monomers in water in the absence of an added protective colloid, said terpolymer contains about 50-86% by wt. VCL, and the rest is vinyl pyrrolidone (VP) monomer and an M.sub.3 monomer, where M.sub.3 is selected from the group consisting of N,N-dimethylanminopropyl methacrylamide (DMAPMA) N,N-dimethylaminoethyl methacrylate, quaternary derivatives thereof,and mixtures thereof; at a polymerization temperature which is at least 35.degree. C. higher than the cloud point of 45.degree. C. of said terpolymer, by the steps of: (a) feeding over time a monomer pre-mix comprising VP and M.sub.3, and initiator, into a reaction vessel containing water as solvent heated to said polymerization temperature, thereby to generate in situ copolymer particles, which function as a dispersing agent for said terpolymer during, the polymerization, (b) thereafter feeding the VCL monomer, and the rest of the VP and M.sub.3 monomers and initiation into said vessel, over a predetermined period, and (c) polymerizing said monomers with said dispersing copolymer therein to provide, upon cooling to room temperature, a clear, viscous aqueous terpolymer solution.