Patent ID: 6693151
Filing Date: 2004-02-17
Classification: C08F

Abstract:
A method of producing a bimodal polymer product, by semi-continuous, aqueous polymerization, comprising,(a) supplying to a single continuously stirred tank reactor, materials used in the polymerization, comprising water, and at least one ethylenically unsaturated monomer, (b) creating in said reactor, conditions causing polymerization of a first polymer mode to proceed, (c) adding a surfactant to initiate growth of a second polymer mode, (d) continuing said supply, under said conditions, producing a bimodal polymer product, (e) continuing said supply to said reactor, while simultaneously removing part of said bimodal polymer product from said reactor, (f) collecting said removed bimodal polymer product in at least one separate vessel, continuing said supply, and maintaining said conditions until the total supply is at least 1.05 reactor volumes and less than to 2 reactor volumes, (g) completing said polymerization reaction in said separate vessel(s), (h) combining together all of the bimodal polymer product.