Filament-reinforced silicone rubber prodn. - where filament of e.g. polyester is drawn through primer, completely dried, passed through vacuum and then extruded

摘要

A filament-reinforced silicone rubber strip is produced by priming filament, drying it free from moisture or primer solvent, passing it through a vacuum chamber, applying the rubber round it, passing it through an extruder die of the required profile, and heating the product in conventional manner. Pref. the filament (2) is drawn from its reel, is polyester. It is drawn through a tank of the primer at a speed to suit the final extruder, ususally 7-14 m/min.. It comes next to the drying oven, which has an extractor to remove solvent vapour (15) and is fed with warm air operating at 70-80 deg. C. The wire makes repeated passes over e.g. 2-3 mins. before moving through the oven at 70-80 deg. C, then through the air and through a chamber connected to a vacuum pump. It moves through the extruder, a curing oven, a second similar oven, received then a coating of talc, and is finally reeled and post-cured in another oven. ADVANTAGE - The method bonds the filament effectively to its silicone rubber, The prod. has a consistently high quality and the process is simple and reliable.