PURPOSE: To provide the title compsn. which gives a coating film which is tough and has excellent whiteness and wear resistance, consisting of an aq. binder and a specified non-film-forming polymer emulsion.
CONSTITUTION: 5W70% (by weight; the same applies hereinbelow) α,β- ethylenically unsaturated carboxylic acid is emulsion-polymerized with 5W95% 1W8C alkyl (meth)acrylate, 0W50% arom. vinyl compd. and 0W50% other monomer at 0W100°C to obtain a copolymer (a). 70W99.9pts.wt. mixture of 0W10% α,β-ethylenically unsaturated carboxylic acid, 0.1W10% monomer having a tert. amino group, 50W99.9% arom. vinyl compd. and 0W49.9% other copolymerizable monomer is emulsion-polymerized in the presence of 0.1W30pts.wt. component (a) to obtain a non-film-forming polymer emulsion (B) having a solid content of 20W60%. 100pts.wt. (on a solid basis) aq. binder (A) (e.g., a vinyl resin emulsion) is blended with 0.1W9,900pts.wt. (on a solid basis) component B and 0W300 pts.wt. pigment (C).