| 摘要 |
<p>A fast curing, coating composition that is adapted for use as an automotive topcoat and which upon curing forms a hard, glossy, durable coating exhibiting excellent resistance to solvents and water. The coating composition which may contain greater than about 55 percent by weight of nonvolatile solids and, exclusive of pigments, solvents and other nonreactive components, consists essentially of:
<UnorderedLists id="ula01" listStyle="none"><ListItem>(A) a bifunctional copolymer bearing hydroxy functionality and pendent epoxy functionality, having a number average molecular weight (M<Sub>n</Sub>) of between about 1500 to about 10.000 and a glass transition temperature (Tg) of between about -25° to about 70°;</ListItem><ListItem>(B) a reactive catalyst comprising at least one phosphonic acid derivative;</ListItem><ListItem>(C) an amino resin crosslinking agent; and</ListItem><ListItem>(D) optionally, a hydrcxy functional additive.</ListItem></UnorderedLists></p><p>The phosphonic acid derivative catalyst is ncluded in the composition in an amount sufficient to provide between about 8 to about 1.4 equivalents of acid functionality in copolymer (A), and the amino resin crosslinking agent is Included in the composition in an amount sufficient to provide at least about .4 equivalents of nitrogen crosslinking functionality for each equivalent of hydroxy functionality included in the composition.</p> |
