Patent ID: 6653407
Filing Date: 2003-11-25
Classification: C08F,Y10S

Abstract:
A process for forming a microgel which comprise a core of crosslinked polymer and multiplicity of substantially linear polymeric arms attached to the core;wherein the process comprises (a) polymerizing monoethylenically unsaturated monomers in the presence of a chain transfer agent to form macromonomers, each having a terminal polymerizable ethylenically unsaturated group and the macromonomers having a weight average molecular weight of 1,000-25,000; (b) polymerizing the macromonomers with monomers of the core comprising monoethylenically unsaturated monomers and 0.5-60 mole percent, based on the total moles of monomers of the core, of multi-olefinic crosslinking monomers containing two or more carbon to carbon double bonds which are crosslinked in the core, to form the microgel having a weight average molecular weight of 104-108; and wherein the monoethylenically unsaturated monomers of the core and the macromonomers are individually selected from the group consisting of alkenes having 1-10 carbon atoms, acrylonitrile, isobornyl (meth)acrylate, haloalkyl (meth) acrylates, alkoxyalkyl (meth)acrylates, cycloalkyl (meth)acrylates, phenoxy (meth)acrylate, alkylene glycol (meth)acrylate, poly(alkylene glycol) (meth)acrylate, N-vinylcarbazole, N-vinylpyrrolidone, vinylpyridine, benzyl (meth)acrylate, vinyl acetate, vinyl chloride, vinylidene chloride, and any mixtures thereof.