Golf balls having an inner core made of a foamed composition are provided. The core assembly preferably includes a foam inner core (center) and surrounding outer core layer. A cross-linked thermoplastic, preferably an ethylene acid copolymer ionomer, is used to form the foam composition. The core layers have different hardness gradients and specific gravity values. The ethylene acid copolymer is reacted with a metallic acrylate salt and peroxide free-radical initiator to form the cross-linked polymer. The foamed, cross-linked composition helps provide the inner core with good resiliency, thermal stability, and durability. Non-foamed thermoplastics or thermosets such as polybutadiene rubber may be used to form the outer core layer. The ball further includes a cover that may be multi-layered.
高尔夫球的内芯由发泡组合物制成。球芯组件最好包括泡沫内芯(中心)和周围的外芯层。交联热塑性塑料,最好是
乙烯酸共聚物离聚物,用于形成泡沫组合物。芯层具有不同的硬度梯度和比重值。
乙烯酸共聚物与
金属
丙烯酸盐和过氧化物自由基
引发剂反应,形成交联聚合物。发泡交联组合物有助于为内芯提供良好的回弹性、热稳定性和耐用性。非发泡热塑性塑料或热固性塑料(如聚
丁二烯橡胶)可用于形成外芯层。球还包括一个可以是多层的外层。