DISPERSION OF ADSORBING EMULSION POLYMER PARTICLES

摘要

The present invention is a composition comprising a stable aqueous dispersion of polymer particles having a core comprising structural units of: a) a phosphorus acid monomer, b) an acid monomer, c) a multiethylenically unsaturated monomer; and d) a polymerizable ethylenically unsaturated bulk monomer; and a shell comprising structural units of a1) a sulfur acid monomer, and b1) a polymerizable ethylenically unsaturated bulk monomer; wherein the core protuberates from the shell and the ratio of the structural units of the sulfur acid monomer to structural units of carboxylic acid monomer in shell is at least 0.2:1. Control of the proportion of sulfur acid monomer units to carboxylic acid monomer units results in an improvement in the viscosity stability of paint formulations containing latexes possessing acorn morphology without sacrificing hiding.

主权项

1. A composition comprising a stable aqueous dispersion of polymer particles having a shell and a core protuberating from the shell, wherein the protuberating core comprises, based on the weight of the core:
a) from 2 to 15 weight percent structural units of a phosphorous acid monomer or a salt thereof; b) from 0.2 to 20 weight percent structural units of a carboxylic acid monomer or a sulfur acid monomer or a salt thereof or a combination thereof; c) from 0.1 to 30 weight percent structural units of a multiethylenically unsaturated monomer; and d) from 50 to 95 weight percent structural units of a polymerizable ethylenically unsaturated bulk monomer;wherein the shell comprises, based on the weight of the shell:
a1) less than 1 weight percent structural units of a phosphorus acid monomer or salt thereof; b1) from 0.1 to 4 weight percent structural units of a sulfur acid monomer or a salt thereof, based on the weight of the shell; c1) less than 2 weight percent structural units of a carboxylic acid monomer or salt thereof; and d1) from 80 to 99 weight percent structural units of a polymerizable ethylenically unsaturated bulk monomer;wherein the ratio of structural units of the sulfur acid monomer to structural units of carboxylic acid monomer is at least 0.2:1 and wherein the weight-to-weight ratio of the shell to the core is in the range of from 3:1 to 50:1.