Process for manufacturing pneumatic tyres

摘要

In a first stage the carcass (1) and unvulcanized rubber (2) is preheated (4) from inside of the carcass to raise the temperature of the interface between carcass and unvulcanized rubber compound to a level below which vulcanization starts to occur. In a second stage the preheated carcass and unvulcanized compounds are located in a mold and vulcanized (16). INDEPENDENTLY CLAIMED is: (a) use of the two part process for tire manufacture. The unvulcanized rubber compound (2) is degassed in a partially filled ram less kneader at 100-150 degrees C and under a 10-100 millibar vacuum. Degassing may also be effected in an on-line vacuum extruder. During mixing the unvulcanized rubber compounds are set to give a scorch time of NOTGREATER 5, preferably NOTGREATER 3 minutes at 130 degrees C. Rubber compound is sprayed onto the carcass at 80-120 degrees C and the tire assembly preheated to 100-170 degrees C with steam. Vulcanized tires are post cured at 60-130 degrees C, preferably 90-110 degrees C.