Patent GB-883108-A (GB)
Title: Elastomer bonded abrasive materials
IPC: B24D11/00
Filed: 1959-11-20
Abstract: 883,108. Abrasive sheet materials. AMERICAN VISCOSE CORPORATION. Nov. 20, 1959 [Dec. 2,1958], No. 39501/59. Addition to 794,725. Class 60. A flexible porous fibrous abrasive sheet-like material of elastomeric fibres disposed in random distribution and bonded to each other at their points of contact and abrasive particles embedded in and covered by a thin layer of the elastomeric material is produced by discharging a non-converging unconfined high velocity stream of gas into the ambient atmosphere, expelling a jet of a solution of an elastomeric material dissolved in a volatile solvent and having abrasive particles suspended therein into the high velocity gas stream, the direction of expulsion being coincident with the gas flow, the gas stream serving to evaporate the solvent and attenuate and break the fibre-forming liquid into discontinuous lengths of fibre, and collecting the fibres with the abrasive particles embedded therein. The collected fibres may be heated to cure the elastomeric material, or if collected in the form of a web may be heated and pressed to densify and cure the web. The abrasive particles may be coated with a phenolic or an epoxy resin before being intermixed with the solution of the elastomer which may be a natural or synthetic rubber or rubber substitute, e.g. crepe rubber, chloroprene polymers, neoprene, butadiene-acrylonitrile copolymers such as "Buna-N", "Butaprene", "Ameripal-D", "Parbunan", "Chemigum" or "Hycar-OR" (Registered Trade Marks) and Paracril, butadiene-styrene copolymers such as Ameripal-F, Hycar-OS and GR-S, isoprene isobutylprene, copolymers such as GR-I and butyl rubber. During the expulsion of the solution and collection of the fibres, the elastomeric material may shrink against and lightly coat the abrasive particles. A secondary stream of gas may be provided to surround or envelope the primary stream of gas and the solution of elastomer containing the abrasive may be expelled through a plurality of spraying units surrounded by high velocity gas streams: The solution may contain gassing or blowing agents. fillers, vulcanizing agents, accelerators and the like rubber compounding agents, examples of which are given. In Fig. 1, elastomeric liquid extruded from spray tip 15 mounted concentrically within nozzle 19, is attenuated to form discontinuous fibres, by a high velocity gas stream passing through nozzle 19. The fibres adhere together on endless collecting means 23 to form web 27 which is passed through rollers 29 prior to stripping from the means 23 and curing or vulcanizing in oven 31. The web 27 may be supported by suitable reinforcement, e.g. glass fibre sheet, to provide an end product of desired strength. In Fig. 2, film forming liquid is extruded through upwardly pointing spray tip 43 into a stream of high velocity gas from concentric nozzle 45 mounted in tower 40. The attenuated fibres formed are carried to the top of the tower by a secondary stream of gas from blower 46 and are collected and held on endless porous surface 47 by suction chest 49 to form web 48 which after stripping from the surface is passed through heater 51. As shown in Figs. 2 and 4 a plurality of towers may be associated to produce webs which may be laminated prior to curing. Again, as in tower 53 of Fig. 2, a plurality of spray tips 56 and gas nozzles 58 may be present in each tower. As shown in Fig. 3, the secondary gas stream may be passed in a direction counter-current to the primary or high velocity gas stream.