LATEX FOR COATINGS HAVING REDUCED BLUSHING CHARACTERISTICS

This invention relates to the synthesis of a latex which can be formulated into coatings having improved water resistance for both moisture vapor transmission and water spotting. Coatings which are formulated with the latex of this invention axe particularly useful for coating metal substrates because they provide excellent rust and corrosion resistance. The subject invention more specifically discloses a process for producing a neutralized latex that is useful in the manufacture of water reducible coatings which comprises: (1) free radical aqueous emulsion polymerizing at a pH of less than about 3.5 a monomer mixture which comprises, based on 100 weight percent monomers: (a) from about 45 to about 85 weight percent vinyl aromatic monomers, (b) from about 15 to about 50 weight percent of at least one alkyl acrylate monomer, and (c) from about 1 to about 6 weight percent of at least one unsaturated carbonyl compound; in the presence of about 0.5 to 4.0 phm at least one phosphate ester surfactant and in the presence of about 0.5 to 4.0 phm of at least one water insoluble nonionic surface active agent to produce a latex; and (2) neutralizing the latex with ammonia to a pH which is within the range of about 7 to about 10.5 to produce the neutralized latex.