| 摘要 |
1,164,466. Abrasive articles. ARMOUR & CO. 28 Sept., 1966 [19 Oct., 1965], No. 43417/66. Heading C4V. Coated abrasive product comprises the layers (a) a backing which is a spun bonded web of linear polyethylene fibres which backing has been impregnated with either polyvinyl chloride, a copolymer of vinyl chloride and vinylidene chloride, or a mixture of (1) an epoxy resin formed by the action of a dihydric phenol with epichlorhydrin, (2) a polyamide and (3) a long chain polyester having a chain length of at least 14 members, (b) a layer of abrasive grains bonded to the impregnated backing by means of a flexible metal adhesive and (c) a top-size coating over the grains composed of an epoxy novolac resin having at least 3 reactive epoxy groups. The preferred dihydric phenol is bisphenol A and the epoxy resins which are particularly suitable have an epoxide equivalent of 170 to 200, a viscosity of 25‹ C. of 3000 to 20,000 centipoises, an average molecular weight of twice the epoxide equivalent and are liquid at room temperature. The polyamide component is preferably a condensation polymer, dimerized and trimerized vegetable oils, unsaturated fatty acids, and an aryl or alkyl polyamine. They have preferably molecular weights of from 3000 to 10,000 and melting points ranging up to approximately 190‹ C. Lower molecular weight polyamides of about 6000 are preferred. In preparing the saturant the epoxy resin, polyamide and polyester are mixed together and thinned with a suitable solvent, preferably volatile, such as methylene chloride. The vinyl chloride polymers and copolymers are preferably colloidal dispersions in water having 48 to 58% total solids and preplasticized or internally plasticized latices are preferred. Suitable plasticizers are dioctyl phthalate, dioctyl adipate and tricresyl phosphate. The impregnation may be accomplished by "dip-squeeze". The make coat for embedding the abrasive grains and uniting the grain to the impregnated sheet may consist of a urethane elastomer. |
