US Patent 7,766,767
Golf balls having a low modulus HNP layer and a high modulus HNP layer
Abstract
The present invention is directed to golf balls consisting of a dual-layer core and a cover. The core consists of a layer formed from a low modulus HNP composition and a layer formed from a high modulus HNP composition. The low modulus HNP composition has a material hardness of 55 Shore D or less and comprises a highly neutralized ethylene/(meth)acrylic acid/alkyl(meth)acrylate copolymer. The high modulus HNP composition has a material hardness of 45 Shore D or greater and comprises a highly neutralized ethylene/(meth)acrylic acid copolymer. The cover preferably consists of a single cover layer.