GB784990A - Improvements in or relating to dynamic seals and material for making them - Google Patents

Abstract

784,990. Proofing against air and liquids; impregnated bearing surfaces; laminates. PRECISION RUBBERS, Ltd., and BLOW, C. M. July 13, 1955 [June 8, 1954; Feb. 14, 1955], Nos. 16763/54 and 4340/55. Class 140. [Also in Group XXVI] A flexible seal of washer, cup or U-section form for pneumatic or hydraulic application is made from a material comprising long-fibred tissue or unwoven fabric sheet impregnated and/or coated with a rubber or rubber-like composition comprising natural or synthetic rubber compounded with a high-styrenebutadiene copolymer together with vulcanizing ingredients, the sheets, if necessary, being combined in two or more layers. The fibrous material may be long-fibred manilla tissue paper which may contain rayon fibres or may be carded or garnetted cotton and/or rayon fibres bonded into handleable form by rubber or similar materials. The rubber composition dissolved in a solvent such as benzene, together with the vulcanizing ingredients, is applied by immersing the sheet in the solution or by spreading the solution on one or both surfaces; different compositions may be applied to opposite surfaces and antifriction material such as graphite may be added to one of the compositions. Where several sheets are placed together to form a laminated material, sheets unimpregnated or only lightly impregnated with the rubber composition may be incorporated in the material and are preferably placed on one or both outer surfaces so as to give a greater proportion of fibrous material at the outer surface or surfaces; a high proportion of graphite may be added to the unimpregnated layers.