Aqueous emulsion polymer associative thickeners

An aqueous emulsion polymer comprising, as copolymerized units:

• from 8% to 25 wt %, based on polymer weight, acid-containing monomer, from 2% to 30 wt %, based on polymer weight, (meth)acrylic acid ester of the formula:
• H2C═C(R)—C(O)—O—(CH2—CH2O)n—Ro, wherein R is H or CH3, n is from 2 to 100 and Ro is a group containing from 4 to 36 carbon atoms, and
• from 35% to 90 wt %, based on polymer weight, (C1-C4) alkyl (meth)acrylate;
• wherein said polymer is formed in the presence of a compound comprising the group —C(═S)—S—.

A process for providing an aqueous emulsion polymer comprising forming an aqueous emulsion polymer comprising, as copolymerized units:

• from 8% to 25 wt %, based on polymer weight, acid-containing monomer, from 2% to 30 wt %, based on polymer weight, (meth)acrylic acid ester of the formula:
• H2C═C(R)—C(O)—O—(CH2—CH2O)n—Ro, wherein R is H or CH3, n is from 2 to 100 and Ro is a group containing from 4 to 36 carbon atoms, and
• from 35% to 90 wt %, based on polymer weight, (C1-C4) alkyl (meth)acrylate;
• by a living free radical polymerization process.

A process for providing an aqueous emulsion polymer comprising

• forming an aqueous emulsion polymer comprising, as copolymerized units:
• from 8% to 25 wt %, based on polymer weight, acid-containing monomer, from 2% to 30 wt %, based on polymer weight, (meth)acrylic acid ester of the formula:
• H2C═C(R)—C(O)—O—(CH2—CH2O)n—Ro, wherein R is H or CH3, n is from 2 to 100 and Ro is a group containing from 4 to 36 carbon atoms, and
• from 35% to 90 wt %, based on polymer weight, (C1-C4) alkyl (meth)acrylate;
• in the presence of a compound comprising the group —C(═S)—S—.