1405257 Coated rubber articles DUNLOP LTD 27 April 1973 [10 May 1972] 21751/72 Heading B2E [Also in Division B7] A multi-component article comprising a natural or synthetic rubber component bonded to a polyurethane component is obtained by contacting the natural or synthetic rubber component with a liquid polyurethane forming composition and covering the composition to form a polyurethane, the surface of the rubber component to be bonded to the polyurethane component having been treated with a modifying agent, which is concentrated nitric acid, halogen substituted isocyanuric acids or a salt of mono- or di-chloroisocyanuric acid, prior to contact wih a liquid composition. The method may be used to form pneumatic vehicle tyres, belling, hose, friction-drive wheels, pulley wheels, solid vehicle tyres and air-springs. The modifying agent may be applied by dipping, spraying or brushing. When nitric acid is used it is an advantage to apply it in the form of a gel, that is a paste of concentrated nitric acid and a fine silica powder. Numerous suitable polyurethane-forming materials are specified. Any natural rubber or a synthetic rubber such as stylene/butadiene rubber may be used to form the rubber component.
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