Method for the production of shoe soles

摘要

Rubber compound is introduced into a tool(2) with a die(5) and side parts(7) at just below the vulcanizing temperature. A punch(6) closes the tool and compresses and prevulcanizes the rubber. Both tool sides are opened and partial vulcanization occurs. After punch removal the rubber layer is cooled and degassed. Controlled under-vulcanization occurs in both latter stages. A molding cavity is then formed between a tool-closing shoe last(8), the tool sides and the rubber layer. Reactive polyurethane(PU) injected into the cavity cures and exothermic heat completes vulcanization of the rubber layer and bonds both layers together. The bonding surface of the rubber layer is increased by impressing. The resulting profile corresponds to that of the sole tread profile so that uniform thickness occurs over the entire sole. The punch(6) is heated to 140-220degreesC, the die(5) to 90-150degreesC and the tool sides to 40-80degreesC. During the degassing stage the partially vulcanized rubber surface is heat activated and degassed with radiant heaters.