Patent ID: 7723436
Filing Date: 2010-05-25
Classification: C08F,C08L,C09J,Y10T

Abstract:
1. A process for preparing a polyacrylate having an at least bimodal molecular weight distribution, which comprises polymerizing a monomer mixture of a1) 70% to 100% by weight acrylic acid and/or acrylic esters of the formula CH a2) 0 to 30% by weight olefinically unsaturated monomers containing functional groups, in an at least two-phase free-radical solvent polymerization in the presence of an organic solvent or in mixtures of organic solvents to give a polyacrylate having an at least bimodal molecular weight distribution, the polymerization being carried out in a first phase of the at least two-phase polymerization, in the presence of a first initiator concentration, to give a first polymer having a first molecular weight and, before the monomer mixture has been completely consumed by the polymerization, a further phase or phases of polymerization is or are started, by the addition at least once of a regulator, and in this further phase or further phases a second polymer or polymers is or are synthesized, said second polymer having a second molecular weight which second molecular weight is lower than said first molecular weight.