摘要 |
The outer shell of a bowling ball, vulcanized in situ onto a spherical core, is formed of a mixture of sulfur-vulcanizable rubber, preferably SBR rubber, inert particulate filler such as rubber dust, sulfur, process oil, and polyurethane, with suitable accelerators and pigment. The polyurethane, comprising about two to about ten percent by weight of the shell, is preferably of a kind that is retarded in curing by the presence of the sulfur and is generally incompatible for polymerization with the rubber; the ball exhibits superior hooking and hitting characteristics and has high oil resistance.
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