| 摘要 |
A stable aqueous dispersion containing cellulose ester, the dispersion being polymeric microparticles comprised of cellulose ester and a polymer formed from at least two different vinyl monomers of which at least one vinyl monomer is polyethylenically unsaturated. The dispersion of microparticles is formed by a high stress technique prior to polymerization of the vinyl monomers in the presence of the cellulose ester. Typically the dispersion also contains surfactant. A method of making the stable, cellulose ester-containing aqueous dispersion by (a) mixing together a cellulose ester, at least two vinyl monomers of which at least one vinyl monomer is polyethylenically unsaturated, surfactant, and water to form an emulsion; (b) particulating the emulsified mixture of (a) into microparticles by a high stress technique; and (c) copolymerizing the vinyl monomers in the cellulose ester-containing particulated emulsion of (b) to form a crosslinked polymer within the microparticles of the dispersion. Also aqueous coating compositions formed from the stable cellulose ester containing aqueous dispersion; crosslinking material; and, optionally, additional film forming resins. The aqueous coating compositions can also contain pigments. The coating compositions are very advantageous, particularly in automotive base coats containing metallic pigments and exhibit good humidity resistance, appearance, adhesion and chip resistance when used in an automotive "low bake repair" process.
|
