In-mold coating of sheet molding compound moldings

摘要

Liquid compositions suitable for hot post-mold coating of cured sheet molding compound (SMC) parts comprise a reaction product of an epoxide and an unsaturated carboxylic acid mixed with a low shrink additive and a filler having a sheet-like structure. These liquid compositions are used to smooth surfaces, fill porosity and other voids and to eliminate or reduce sink marks. Coatings typically are cured in less than two minutes and appear able to provide many features of normal painting without paint facilities except possibly those needed for touch- up.PP The application method used to date has been to compression mold an SMC part in the usual way, separate the mold halves, inject the liquid composition and reclose the mold for a second cure cycle. A unique feature of the liquid composition is its ability to adhere to an uncleaned SMC molding.