Acid functional two-stage polymer dispersion with neutralization between polymerization stages

US6423769B1 · kind B1 · utility

Assignee

• BASF SE

Inventors

• Matthias Gerst · Maikammer, DE
• Alexander Centner · Ludwigshafen am Rhein, DE

Key dates

• Filing date: Dec 14, 1999
• Grant date: Jul 23, 2002
• Expiry date: Dec 14, 2019

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C09D5/34
• WIPO field: Basic materials chemistry
• WIPO sector: Chemistry

Abstract

An aqueous polymer dispersion wherein the polymer particles include at least two different water-insoluble polymers P and P′, obtained by free-radical polymerization of ethylenically unsaturated monomers, which includes the following measures:(1) polymerizing a first monomer mixture M by the method of free-radical aqueous emulsion polymerization to give a polymer P, wherein the polymerization is carried out in an aqueous reaction medium having a pH of less than 5,(2) adding a base to the dispersion of the polymer P to raise the pH of the dispersion by at least 2 pH units, and(3) polymerizing a further monomer mixture M′, which is different from the monomer mixture M, in the dispersion of the polymer P, to give a polymer P′,the monomer mixtures M and M′ independently of one another including from 0.1 to 5% by weight, based on the total amount of the monomers M and M′, respectively, of at least one monomer M1 which has at least one acid group and from 95 to 99.9 by weight of one or more monoethylenically unsaturated, essentially hydrophobic monomers M2, and wherein the polymerization of the first monomer in (1) is carried out to a conversion of at least …