Method for manufacturing plastic bowling pins

摘要

A method for manufacturing a plastic bowling pin that has a porous core and a resilient envelope includes the step of blow-forming the envelope in a blowing mold and removing the envelope from the blowing mold. The envelope is then cooled to a temperature of 60 DEG C. to 100 DEG C. A core plastic material containing an exothermic agent is then injected into the envelope for forming the core. The core plastic material is heated to a temperature of 200 DEG C. to 260 DEG C. The inner layer of the envelope is thus fused to the plastic material of the core to provide an intimate connection between the envelope and the core.