Method of curing rubber extrusions

Claim 1

A PROCESS OF MAKING AN ARTICLE WHICH IS SHAPED BY EXTRUSION AND IS OBTAINED IN A CURED STATE IN A SUBSTANTIALLY CONTINUOUS MANNER, WHICH COMPRISES SUBSTANTIALLY UNIFORMLY INCORPORATING INTO A CURABLE SPONGE COMPOUND COMPRISING A BLOWING AGENT AND AN ORGANIC POLYMERIC BINDER, WHICH IS SUITABLY COMPOUNDED TO CURE AT ELEVATED TEMPERATURES, AT LEAST 2 PERCENT OF THE WEIGHT THEREOF OF A FINELY DIVIDED MAGNETIC IRON OXIDE TO FORM A MIXTURE, EXTRUDING SAID MIXTURE INTO AN INDUCTION HEATING ZONE OF DESIRED CROSS SECTIONAL SHAPE, COMPRISING NONMAGNETIC WALLS WHEREIN SAID MIXTURE IS SUABJECTED TO A HIGH FREQUENCY MAGNETIC FLED TO HEAT IT TO A VULCANIZING TEMPERATURE, MAINTAINING THE MIXTURE IN THE DESIRED CROSS SECTIONAL SHAPED FORM WHILE MOVING IT WITH RESPECT TO SAID ZONE AND WITH RESPECT TO THE CONFINING WALLS OF SAID ZONE, AND PASSING THE MIXTURE CONTINUOUSLY FROM SAID INDUCTION HEATING ZONE INTO LUBRICATED CONTACT WITH FLUID HEATED WALLS OF A CURING CHAMBER HAVING A CROSS SECTION OF THE DESIRED SHAPE, AND THEREAFTER MAINTAINING SAID MIXTURE AT A VULCANIZING TEMPERATURE BY CONTACT WITH SAID HEATED WALLS OF SAID CURING CHAMBER FOR A SUFFICIENT TIME TO CAUSE CURING OF SAID POLYMERIC BINDER.