Acrylic-methylene succinic ester emulsion copolymers for thickening aqueous systems

A copolymer obtained by aqueous emulsion copolymerization of a monomer system comprising

• (A) about 1 to about 25 percent of at least one substituted monomer of the formula:
• ##STR11## in which x is an integer from 1 to 150, and y is an integer from 0 to 50, where R is alkoxy, alkylphenoxy, dialkylphenoxy, or alkyl carbonyloxy having 5 to 30 carbon atoms, or a sorbitan fatty ester of the formula ##STR12## where each of p, q, r and s is an integer and the sum of said integers is from 0 to 100, R.sub.1 is H or --COR.sub.2 and R.sub.2 is alkyl, alkylphenyl, or dialkylphenyl having 5 to 30 carbon atoms;
• (B) about 5 to about 70 percent of a copolymerizable .alpha., .beta.-ethylenically unsaturated carboxylic acid monomer of the formula ##STR13## where R is H and R.sub.1 is H, an alkyl group containing from 1 to 4 carbon atoms, or --CH.sub.2 COOX;
• R is --COOX and R.sub.1 is H, and X is H or an alkyl group containing from 1 to 4 carbon atoms,
• (C) about 10 to about 90 percent of at least one nonionic, copolymerizable .alpha., .beta.-ethylenically unsaturated monomer of the formula
• CH.sub.2 .dbd.CYZ
• where Y is H and Z is CN, Cl, --COOR, --C.sub.6 H.sub.4 R, ##STR14## or --CH.dbd.CH.sub.2;
• Y and Z are Cl, and Y is CH.sub.3 and Z is CN, ##STR15## --CH.dbd.CH.sub.2, --C.sub.6 H.sub.4 R, or --COOR.sub.1, and R is H, Cl, Br or alkyl containing from 1 to 4 carbon atoms;
• R.sub.1 is alkyl containing from 1 to 12 carbon atoms, or hydroxyalkyl containing from 2 to 8 carbon atoms, and R.sub.2 is alkyl containing from 1 to 8 carbon atoms;
• and
• (D) up to 1 percent of a copolymerizable polyethylenically unsaturated cross-linking monomer, said percentages being by weight, based on the total weight of said monomers.