Thickening agent for aqueous compositions

As a thickening agent for aqueous systems, a composition comprising a mixture of:

• (A) a water swellable clay mineral, and
• (B) a water insoluble emulsion polymer, an aqueous dispersion of which will thicken upon addition of a neutralization agent, of
• (1) 20-50 wt. % of (meth)acrylic acid,
• (2) 0.5-25 wt. % of at least one monomer of the formula (I):
• H.sub.2 C.dbd.C(R)--C(O)--O--(CH.sub.2 CH.sub.2 O).sub.n --R.sup.o
• wherein R is H or CH.sub.3, n is at least 2 and has an average value up to 60 or more, and R.sup.o is a group having at least 8 carbon atoms selected from alkyl, alkaryl and polycyclic hydrocarbyl,
• (3) at least 30 wt. % of an alkyl (meth)acrylate wherein the alkyl group has 1 to 4 carbon atoms, and
• (4) zero to 1.0 wt. % of a polyethylenically unsaturated monomer;
• the proportions of (A) and (B) being effective, upon addition of a neutralizing agent for (B), for thickening an aqueous dispersion formed therewith.