Disclosed herein is a two-piece type solid golf ball formed by enclosing a solid core with a thermoplastic resin cover. It provides a long overall distance, improved controlability, extended durability, and good shot feeling. The solid core contains polybutadiene having more than 40% of cis-1,4 bonds...http://www.google.com/patents/US4919434?utm_source=gb-gplus-sharePatent US4919434 - Golf ball
