Abstract: Mineral-filled thermosetting molding compositions having both precision-molding or low-shrink characteristics and also high abrasion resistance, plus other desirable properties. "Low profile" molding compositions, known to give smooth surface configurations, have low-shrink properties which also give precision molding characteristics of value in mechanically interfitting molded parts, but have such poor abrasion resistance as to be unusable for desirable applications. Both low-shrink and high abrasion resistance are obtained, with other desired properties, by including a known abrasion-improving polyolefin and by using a long-fiber asbestos as the reinforcing fiber, particularly either chrysotile asbestos or that known as blue asbestos or crocidolite.

Abstract: An integrally bonded composite structure of a substrate part or layer of metal or the like, an elastic interface layer, and a thermoset plastic wall or layer molded in place against it is formed by: (1) coating the substrate, as by spraying, with a thin coating of a thermosetting soluble elastomer, such as a chloroprene rubber (Neoprene), formulated to chemically bond to the substrate surface, and also containing a coupling agent which will react with the thermoset plastic layer during curing of the latter; (2) heating the coating to dry and stabilize the same on the substrate so as to withstand transfer flow of molding composition but without completely curing the coating composition; and (3) molding the plastic layer against the coated substrate under heat and pressure as in a heated molding die while the coating is in incompletely cured state, and thereby completing the curing of the coating as the molded plastic layer is cured and producing an integral chemical bond from the molded layer through the inter

Abstract: Mineral-filled thermosetting molding compositions having improved abrasion resistance. The addition of up to 10% polyethylene or other polyolefin greatly improves the abrasion resistance of conventional molding compositions containing 15% to 60% thermosetting resin, 40% to 85% mineral filler of which 50% may be fiberglass or other fibrous reinforcement. The addition is especially applicable with free radical initiated polymers, particularly polyester resins and epoxy-polybutadiene resins, with which it cross links. In some cases flexure strength is also slightly improved.