Aqueous polymer dispersion obtainable by free-radically initiated emulsion polymerization in the presence of lignosulfonate

摘要

Described is an aqueous polymer dispersion comprising a chain growth addition polymer obtainable via free-radically initiated emulsion polymerization from ethylenically unsaturated, free-radically polymerizable monomers, wherein the chain growth addition polymer is formed to an extent of not less than 60 wt % from primary monomers selected from vinylaromatic compounds, conjugated aliphatic dienes, vinyl esters of saturated C1- to C20-carboxylic acids, esters of acrylic acid or of methacrylic acid with monohydric C1- to C20-alcohols, aliphatic hydrocarbons having 2 to 8 carbon atoms and one or two double bonds, or mixtures thereof, wherein the monomers are polymerized in the presence of lignosulfonate and wherein the chain growth addition polymer is branched or crosslinked. Also described is a process for preparing the aqueous polymer dispersion. The polymer dispersion is useful for preparing paper coating compositions.

主权项

1. An aqueous polymer dispersion, comprising:
particles of a crosslinked or branched chain growth addition polymer; and a lignosulfonate; wherein the chain growth addition polymer comprises: not less than 50 wt % of at least one polymerized primary monomer selected from the group consisting of vinylaromatic compounds, conjugated aliphatic dienes, vinyl esters of saturated C1- to C20-carboxylic acids, esters of acrylic acid with monohydric C1- to C20-alcohols, esters of methacrylic acid with monohydric C1- to C20-alcohols, aliphatic hydrocarbons having 2 to 8 carbon atoms and one or two double bonds, and at least one copolymerized branching or crosslinking monomer other than the at least one primary monomer which is selected from monomers having two or more free-radically polymerizable, ethylenically unsaturated groups; wherein the monomers are polymerized via free-radically initiated emulsion polymerization in the presence of the lignosulfonate and wherein a content of the lignosulfonate is from 10 to 100 parts by weight per 100 parts by weight of a total of the primary and the branching or crosslinking monomers.