Waterbased coating composition of methylol (meth)acrylamide acrylic polymer, acrylic hydrosol and melamine crosslinking agent

Claim 1

A waterbased coating composition comprising about 10-30% by weight of film forming binder dispersed in an aqueous carrier and having a pH of about 7-10; wherein the binder consist essentially of a blend of about a. 20-85% by weight, based on the weight of the binder, of an methylol (meth) acrylamide acrylic latex polymer having a particle size of about 0.06-2.0 microns consisting essentially of polymerized monomers of alkyl methacrylate, alkyl acryalte or mixtures thereof, 1-15% by weight, based on the weight of the acrylic polymer of ethylenically unsaturated carboxylic acid having reactive carboxyl groups, 0.5-10% by weight of ethylenically unsaturated hydroxyl containing monomer and the polymer, having a glass transition temperature of -40° to +40° C. and a weight average molecular weight of 500,000 to 3,000,000, the carboxyl groups of the carboxylic acid component of the polymer are reacted with ammonia or an amine; b. 10-40% by weight, based on the weight of the binder, of an acrylic hydrosol polymer having a particle size of less than 0.30 microns comprising a methylol (meth) acrylamide acrylic polymer containing about 0.5-10% by weight, based on the weight of the polymer, of an ethylenically unsaturated carboxylic acid, 0.5-10% by weight, base on the weight of the polymer, of an ethylenically unsaturated hydroxyl containing monomer and having a weight average molecular weight of about 5,000-75,000 and the carboxyl groups of the carboxylic acid of the polymer are reacted with ammonia or an amine, c. 5-40% by weight, based on the weight of the binder, of a water soluble or water dispersible alkylated melamine formaldehyde crosslinking agent having 1-4 carbon atoms in the alkylated group.