Forming protective skin on intricately molded product

A process for molding in a mold having relatively sharp bends and intricately curving, irregular surface contours a two part bulk particle comprising a sheet molding compound of relatively inferior physical properties and subject to exhibiting sink marks, porosity, waviness, pits, dimples, and the like after molding, defining the bulk of said article, and a resinous film of relatively superior physical properties, having little or no tears or film blemishes after molding, coating said sheet molding compound, said process comprising:

• (a) heating the mold to a temperature sufficient to fuse dry particles of a polyester resin as hereinafter defined,
• (b) electrostatically spraying the mold with substantially dry particles of a partially, cured, cross-linkable polyester resin to fuse said particles and cause them to flow and form a substantially continuous film on said mold, said sprayed particles having an average size of about 70 to about 325 U.S. Standard sieve,
• (c) said polyester resin particles containing within the particles themselves:
• (1) the reaction product of an organic glycol of about 2 to about 12 carbon atoms with a dicarboxylic acid of about 2 to about 16 carbon atoms or an anhydride thereof, a cross-linking amount of a monomer selected from the class consisting of styrene, vinyl toluene, methyl acrylate, methyl methacrylate, diallyl phthalate, acrylamide, diacetone acrylamide, divinyl phthalate, dimethyl fumarate, diethyl fumarate, dially chlorendate, diallyl melamine, and oligomers thereof,
• (2) a catalytic amount of a peroxide catalyst,
• (3) from about 0.05% to about 5% by weight of the polyester of a surface active agent as a flow agent effective to cause said polyester resin particles to flow along the mold after said fusing,
• (d) adding to the mold a heat-curable, bulk sheet molding compound compatible with said polyester resin, and
• (e) heating the mold simultaneously to completely cure the polyester film and the bulk molding compound and interract the bulk compound and polyester resin together to mold said bulk molding compound with a film thereabout of said polyester resin, said molded film having little or no tears or film blemishes in spite of the intricately curved, irregular surface contours of the mold.