Golf balls having an initial velocity greater than 255 ft/sec and/or an overall distance of greater than 320 yards are disclosed. The golf balls comprise one or more core layers, one or more cover layers, and optionally one or more intermediate layers disposed between the core and the cover. At least one layer is optionally formed from a composition comprising from 2 wt % to 50 wt % of a plasticizer, based on the total weight of the composition.

A golf ball 2 includes a core 4, a mid layer 6, a reinforcing layer 8, and a cover 10. When distances (%) from the central point of the core 4 to nine points and JIS-C hardnesses at the nine points, which are obtained by dividing a region from the central point of the core 4 to the surface of the core 4 at intervals of 12.5% of the radius of the core 4, are plotted in a graph, R.sup.2 of a linear approximation curve obtained by a least-square method is equal to or greater than 0.95. The difference (H(100)-H(0)) between a JIS-C hardness H(100) at the surface of the core 4 and a JIS-C hardness H(0) at the central point of the core 4 is equal to or greater than 15.

Golf ball having CoR of at least 0.810, specific gravity SG.sub.B of less than 1.00 g/cc, and initial velocity of at least 250 ft/s and comprising a first layer L.sub.1, a second layer L.sub.2 surrounding L.sub.1, and a third layer L.sub.3 surrounding L.sub.2. L.sub.1 is formed from at least one highly neutralized polymer and has first specific gravity SG.sub.1; L.sub.2 is formed from at least one partially neutralized polymer and has second specific gravity SG.sub.2; and L.sub.3 is formed from at least one of a thermoset or thermoplastic composition and has third specific gravity SG.sub.3. At least two of SG.sub.1, SG.sub.2, and SG.sub.3 is less than 1.13 g/cc. SG.sub.1 may be less than 1.13 g/cc, or less than 1.0 g/cc. The thermoset or thermoplastic composition may comprise polyurethane(s), polyurea(s), polyurethane(s)/polyurea(s) hybrids, and/or ionomers such as at least partially neutralized polymers and/or HNPs.

An ultra-low compression golf ball is disclosed herein. The core preferably has a PGA compression less than 30. The mantle layer and cover have approximately the same thickness. The cover comprises a thermoplastic polyurethane material and has a specific gravity greater than the core and mantle layer. The golf ball has a PGA compression less than 75 and a COR of at least 0.780.

A golf ball can include a core, a mid layer, and a cover. An amount P(Na) of a sodium ion-neutralized ionomer resin in abase resin of the cover can be not greater than 5 parts by mass. The golf ball can satisfy the following mathematical formulas (1) and (2):

[00001]$\begin{array}{cc}\mathrm{Fm}/\left(\mathrm{Hm}*\mathrm{Tm}\right)-\mathrm{Fc}/\left(\mathrm{Hc}*\mathrm{Tc}\right)3.,\mathrm{and}& \left(1\right)\end{array}$$\begin{array}{cc}\mathrm{Mc}*\mathrm{Tc}10.,& \left(2\right)\end{array}$

where Hm: hardness (Shore D) of the mid layer, Tm: thickness (mm) of the mid layer, Fm: bending stiffness (MPa) of the mid layer, Tc: thickness (mm) of the cover, Fc: bending stiffness (MPa) of the cover, and Mc: melt flow rate (g/10 min) of the cover at a temperature of 190 C. under a load of 2.16 Kg.

Golf ball incorporating core consisting of: a solid inner core layer consisting of a peroxide cured polybutadiene rubber composition and having a diameter of 1.25 inches or less and a center Shore C hardness (H.sub.Center) of 50 or less; and an outer core layer consisting of a thermoplastic composition Tc as defined herein and having a thickness of 0.400 inches or greater and an outer surface Shore C hardness (H.sub.outer surface) of 70 or greater, wherein H.sub.outer surface>H.sub.center, and H.sub.outer surfaceH.sub.center40. The peroxide cured polybutadiene rubber composition may comprise a reaction product of polybutadiene and a sufficient amount of peroxide to form the solid inner layer having the center Shore C hardness (H.sub.center) of 50 or less. In one embodiment, 100 phr polybutadiene and from about 0.05 phr to about 3.0 phr of peroxide are mixed with at least one of 5 phr or less of a metal oxide; 5 phr or less of a metal coagent; or 5 phr or less of a metal carbonate. Alternatively, the solid inner core layer has a diameter of 1.10 inches or less or less than 1.0 inches.

The present invention is directed to multi-layer golf balls including a layer formed from a composition comprising a relatively soft or low modulus HNP, a layer formed from a composition comprising a relatively hard or high modulus HNP, an inner cover layer formed from a thermoplastic composition, and an outer cover layer.

The present invention is directed to multi-layer golf balls including a layer formed from a relatively soft or low modulus HNP composition and a layer formed from a relatively hard or high modulus HNP composition. Optionally, the soft (or low modulus) HNP composition and/or the hard (or high modulus) HNP composition is plasticized or is replaced with a different plasticized acid copolymer composition.

An ultra-low compression golf ball is disclosed herein. The core preferably has a PGA compression less than 30. The mantle layer and cover have approximately the same thickness. The cover comprises a thermoplastic polyurethane material and has a specific gravity greater than the core and mantle layer. The golf ball has a PGA compression less than 75 and a COR of at least 0.780.

An ultra-low compression golf ball is disclosed herein. The core preferably has a PGA compression less than 30. The mantle layer and cover have approximately the same thickness. The cover comprises a thermoplastic polyurethane material and has a specific gravity greater than the core and mantle layer. The golf ball has a PGA compression less than 75 and a COR of at least 0.780.