Aqueous latex coating compositions

摘要

Disclosed are aqueous latex-based coating compositions which comprise a blend of an ethylene-vinyl acetate emulsion copolymer component and a selected type of acrylic emulsion copolymer component. The acrylic copolymer component comprises primarily acrylate ester co-monomers or acrylic ester co-monomers and vinyl aromatic, e.g., styrene, co-monomers. The blend of these two emulsion copolymer types also contains a specific type of hydrazine-based, water-soluble cross-linking agent which can eventually react with the acrylic emulsion copolymer component. The acrylic emulsion copolymer is one which contains minor amounts of both 1) carboxy functional co-monomers such as itaconic and/or (meth)acrylic acids, and 2) keto- or aldehyde-containing co-monomers such as diacetone acrylamide. Such latex-based coating compositions can be formulated in the form of water-based paint compositions. These paint products provide paint coatings that exhibit desirable dry and wet adhesion characteristics and desirable resistance to blocking.

主权项

1. An aqueous latex-based coating composition, said composition comprising a blend of an ethylene-vinyl acetate emulsion copolymer and an acrylic emulsion copolymer wherein:
(a) the ethylene-vinyl acetate emulsion copolymer comprises an emulsion polymerization product of: from about 5 wt % to about 20 wt % of ethylene, from about 70 wt % to about 95 wt % of vinyl acetate, and from about 0 wt % to about 10 wt % of one or more auxiliary co-monomers; said ethylene-vinyl acetate emulsion copolymer being present in the blend in an amount from about 50 wt % to about 95 wt %, based on total weight of ethylene-vinyl acetate and acrylic emulsion copolymers; and (b) the acrylic emulsion copolymer comprises an emulsion polymerization product of: from about 70 wt % to about 99 wt % of one or more C1-C12 esters of (meth)acrylic acid or one or more of said C1-C12 esters of (meth)acrylic acid in combination with one or more vinyl aromatic co-monomers, from about 0.1 wt % to about 10 wt % of one or more carboxy-functional co-monomers selected from (meth)acrylic acids, crotonic acid, itaconic acid, and combinations of these carboxy-functional co-monomers, from about 0.1 wt % to about 10 wt % of one or more carbonyl functional co-monomers, and from about 0 wt % to about 10 wt % of one or more auxiliary co-monomers; said acrylic emulsion copolymer being present in the blend in an amount from about 5 wt % to about 50 wt % based on total weight of ethylene-vinyl acetate and acrylic emulsion copolymers, and (c) the blend further comprises a water-soluble cross-linking agent comprising at least two hydrazine moieties, said water-soluble cross-linking agent being present in said blend in an amount such that the molar ratio of hydrazine groups to carbonyl groups of the acrylic emulsion copolymer in said blend is between about 0.1 and 2.0.