Patent GB-929187-A (GB)
Title: Abrasive articles having unsaturated organic polymeric bonds and the like
IPC: B24D18/00
Filed: 1960-07-21
Abstract: Abrasive articles, e.g. porous wet grinding wheels are manufactured by coating abrasive grains such as hard oxides and/or carbides, e.g. aluminium oxide, silicon carbide, with alkenyl polysiloxane, adding a binding agent comprising unsaturated polymer and, if desired, resin, and compacting and baking the mixture, e.g. at 120 DEG C. to 200 DEG C.  The abrasive grains may comprise from at least 5 to 50%, or even up to 99%, of the article weight, preferably have a knoop hardner greater than 1000, a grain size in the range 220 to 4 grit (U.S. Standard Screen) and are coated with at least 10-8, preferably 10-7 to 10-5, grams per cm2 of their surface of the alkenyl siloxane which is derived from the basic silane structure: <FORM:0929187/III/1> where R is alkenyl, e.g. vinyl, allyl, C is a hydrolysable group, e.g. methoxy, ethoxy, halogen or hydrogen, and A and B either the same or different groups consisting of R and C or are non-hydrolysable and non-reactive with unsaturated polymer.  The binding agent preferably comprises from 3% to 6% unsaturated organic polymer, e.g. one or more of natural rubber, isoprene, polybutadiene, butadiene-styrene, butadiene acrylonitrile, chloroprene, polyester resin, together with 97% to 94% resin, e.g. one or more of phenolic, shellac, aniline-formaldehyde, vinylbutyral, epoxy, or coumarone-indene resins.  Vulcanizing agents, e.g. sulphur, fillers, e.g. clay, iron pyrites, calcium oxide, plasticizers, e.g. anthracine oil, and curing accelerators may be incorporated.  In the example the total porosity of the products was at least 10%.ALSO:Abrasive articles, e.g. grinding wheels, are manufactured by coating abrasive grains, e.g. hard oxides and/or carbides such as aluminium oxide, silicon carbide, with alkenyl polysiloxane, adding a binding agent comprising unsaturated polymer and, if desired, resin, and compacting and baking the mixture, e.g. at 120 DEG  to 200 DEG C.  The abrasive grains may comprise from at least 5 to 50%, or even up to 99%, of the article weight, preferably have a Knoop Hardnen greater than 1,000, a grain size in the range No. 220 to 4 grit (Standard U.S. Screen) and are coated with at least 10-,8 preferably 10-7 to 10-5, grams per cm2 of their surface, of the alkenyl siloxane, which is derived from the basic structure <FORM:0929187/IV(a)/1> where R is alkenyl, e.g. vinyl, allyl, C a hydrolysable group, e.g. methoxy, ethoxy, halogen or hydrogen, and A and B either the same or different groups consisting of R and C or are non-hydrolysable groups which are non-reactive with unsaturated polymer.  The binding agent preferably comprises from 3 to 6% unsaturated organic polymer, e.g. one or more of natural rubber, isoprene, polybutadiene, butadiene-styrene, butadiene acrylonitrile, chloroprene, polyester resin, together with 97 to 94% resin, e.g. one or more phenolic, shellac, aniline, formaldehyde, vinyl butyral, epoxy or coumareneindene resins. Vulcanizing agents, e.g. sulphur, fillers, e.g. clay, iron pyrites, calcium oxide, plasticizers, e.g. anthracene oil, and curing accelerators may be incorporated.ALSO:Abrasive articles, e.g. porous wet grinding wheels, are manufactured by coating abrasive grains such as hard oxides and/or carbides, e.g. aluminium oxide, silicon carbide, with alkenyl polysiloxane, adding a binding agent comprising unsaturated polymer and, if desired, resin, and compacting and baking the mixture, e.g. at 120 DEG C. to 200 DEG C.  The abrasive grains may comprise from at least 5% to 50%, or even up to 99%, of the article weight, preferably have a knoop hardness greater than 1000, a grain size in the range 220 to 4 grit (U.S. Standard Screen) and are coated with at least 10-8, preferably 10-7 to 10-5, grams per cm2 of their surface of the alkenyl siloxane which is derived from the basic silane structure:- <FORM:0929187/V/1> where R is alkenyl, e.g. vinyl, alkyl, C a hydrolysable group, e.g. methoxy, ethoxy, halogen or hydrogen, and A and B either the same or different groups consisting of R and C or are non-hydrolysable and non-reactive with unsaturated polymers.  The binding agent preferably comprises from 3 to 6% unsaturated organic polymer, e.g. one or more of natural rubber, isoprene, polybutadiene butadiene-styrene, butadiene-acrylonitrile, chloroprene, polyester resin, together with 97 to 94% resin, e.g. one or more phenolic, shellac, aniline-formaldhyde, vinyl-butyral, epoxy, or coumarene-indene resins.  Vulcanising agents, e.g. sulphur, fillers e.g. clay, iron pyrites, calcium oxide, plasticizers, e.g. aultracine oil and curing accelerators may be incorporated.  In the examples the total porosity of the products was at least 10%.