Patent ID: 7988903

Claim:
A process for blending, injection molding and curing of a rubber compound, comprising the steps of: (a) feeding simultaneously separate streams of a first rubber compound, a second rubber compound, and optionally one or more additional rubber compound into an injection chamber of an injection press where the streams of rubber are combined; (b) injecting a stream of combined rubber compounds resulting from step (a) from the injection chamber at a pressure of at least 10,000 psi into a motionless mixer sealedly provided downstream of the injection chamber , wherein the stream of combined rubber compounds is forced to split up and rejoin successively as the stream advances through the motionless mixer, resulting in successively increased blending of the rubber compounds to form a blended rubber stream; and (c) feeding the blended rubber stream into a mold sealedly provided downstream of the motionless mixer, wherein (1) the first rubber compound comprises (a) an elastomer and (b) at least one vulcanizing agent, (2) the second rubber compound comprises (a) an elastomer and (b) at least one cure accelerator, and (3) the one or more optional additional rubber compound comprises (a) at least one elastomer, wherein the elastomer (1)(a) and the elastomer (2)(a) are the same, or belong to the same family of elastomers, and the vulcanizing agent (1)(b) and the cure accelerator (2)(b) together function as a cure system for the elastomers (1)(a) and (2)(a), the first rubber compound comprising no cure accelerator (2)(b) and the second rubber compound comprising no vulcanizing agent (1)(b), and at least one elastomer selected from the group consisting of the elastomer (1)(a), the elastomer (2)(a) and the elastomer (3)(a) has a Mooney viscosity in the range of 20-75 as measured at 100° C. in accordance with ASTM D1646.