Color-clear composite coatings having improved hardness, acid etch resistance, and mar and abrasion resistance

DETAILED DESCRIPTION In a color-plus-clear application, a composite coating is applied to a substrate The process comprises applying to the substrate a pigmented or colored film-forming composition to form a base coat and applying to the base coat a second film-forming composition to form a transparent top coat, or clear coat, over the base coat.
In a particularly preferred embodiment, additional coating layers such as a primer and/or a primer-surfacer may be applied to the substrate prior to application of the base coat.
The base coat and clear coat compositions used in the process of the present invention preferably are formulated into liquid high solids coating compositions, that is, compositions containing greater than 40 percent, preferably greater than 50 percent by weight resin solids.
The solids content is determined by heating a sample of the composition to 105 -110.
degree.
C.
for 1-2 hours to drive off the volatile material and measuring relative weight loss.
Although the compositions are preferably liquid coating compositions, they may be formulated as powder coating compositions.
The film-forming composition of the base coat can be any of the compositions useful in coatings applications, particularly automotive applications.
The film-forming composition comprises a resinous binder, a tricarbamoyl triazine compound having the formula C.
sub.
3 N.
sub.
3 (NHCOXR).
sub.
3, wherein X is nitrogen, oxygen, sulfur, phosphorus, or carbon, and R is a lower alkyl group having 1 to 12 carbon atoms, or mixtures of lower alkyl groups, and a pigment to act as the colorant.
Particularly useful resinous binders are acrylic polymers, polyethers, polyesters, including alkyds, and polyurethanes, which are described in detail in U.
S.
Pat.
No.
4,650,718.
The acrylic polymers may be copolymers of one or more alkyl esters of acrylic acid or methacrylic acid optionally together with one or more other polymerizable ethylenically unsaturated monomers.
These polymers are preferably of the thermosetting crosslinking type