| 摘要 |
An epoxy resin coating composition for low temperature film formation and rapid cure on preheated substrates comprises a uniform mixture of powdered components having a particle size 5 to 600 m . The first powder is a mixture of epoxy resin having epoxy equivalency > 1, M.W. 450-2550 and softening pt. > 65 DEG C. which is partially reacted with a BF3-amine complex. The second powder is a polycarboxylic acid anhydride which is present to provide 0.25 to 1.0 equivalents of anhydride per equivalent of epoxy resin. The coating coalesces to a continuous coating above 100 DEG C. (e.g. 125-200 DEG C.). Suitable BF3-amine complexes are derived from: monoethylamine, dibenzylamine, hexylamine, 2-ethylhexylamine and piperidine. Examples of anhydrides are those derived from tetrahydrophthalic, cyclopentane tetracarboxylic, hexachloroendomethylene, tetrahydrophthalic, pyromellitic, trimellitic and benzophenone tetracarboxylic acids. The composition may also contain from 0.5 to 3 parts by weight per 100 parts of epoxy resin of colloidal silica. It may also contain up to 70% of the total weight of the composition of colouring agents and fillers all having a particle size > 325 mesh (U.S.A. Standard). The composition may be prepared by dissolving the BF3-amine complex in the epoxy resin above its softening point, rapidly cooling and solidifying and grinding the mixture which is then blended with the powdered anhydride.
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