A golf ball is provided that includes at least two layers of material disposed between a spherical core and a cover layer, wherein the elastic modulus of each is within three orders of magnitude of each adjacent layer or core. The spherical core can be a hollow metal core. This results in a golf ball that is legal for play and capable of drive distances essentially equivalent to those of currently available high performance golf balls, but also provides a golf ball that has less hook and slice during play.

A golf ball is provided that includes at least two layers of material disposed between a spherical core and a cover layer, wherein the elastic modulus of each is within three orders of magnitude of each adjacent layer or core. The spherical core can be a hollow metal core. This results in a golf ball that is legal for play and capable of drive distances essentially equivalent to those of currently available high performance golf balls, but also provides a golf ball that has less hook and slice during play.

Multi-layered golf balls having a dual-layered core and cover of at least one layer are provided. The dual-core construction includes a non-foamed inner core (center) made of a thermoplastic or thermoset composition such as polybutadiene rubber. An outer core layer comprising a foamed composition, such as polyurethane foam, is disposed about the inner core. In one version, the foamed outer core layer is made of a relatively soft foam composition having low flex modulus and density. The foamed outer core layer may specific gravity gradient within the layer, wherein the outer surface specific gravity is greater than the midpoint specific gravity. A cover may be disposed about the core structure. For example, an inner cover made of ethylene acid copolymer ionomer and outer cover made of polyurethane may be used.

Golf balls having multi-layered covers are provided. Preferably, the ball includes an inner cover layer made of an aromatic polyurethane composition; and an outer cover layer made of an aliphatic polyurethane composition. At least one of the cover layers is formed by casting an aromatic or aliphatic thermoplastic polyurethane composition. Ethylene acid copolymer ionomers can be used to make a second inner cover layer. The cover layers are disposed about a single or multi-layered core. The invention also includes casting methods for making such multi-layered covers. The resulting ball has good light-stability, cut/shear-resistance, and impact durability.