Multi-core golf ball having increased initial velocity at high swing speeds relative to low swing speeds

摘要

A golf ball having certain relationships and values of its initial velocities at various club head speeds is provided. The golf ball has a typical initial velocity at a low club head speed, but an increased initial velocity at a high club head speed. Therefore, the golf ball may be advantageously used by both amateur golfers having lower swing speeds and professional golfers having high swing speeds. The golf ball may also achieve an initial velocity of at least about 173 mph at a club head speed of about 125 mph, therefore achieving an increased total shot distance.

主权项

1. A golf ball comprising:
an inner core, the inner core comprising a thermoplastic resin; wherein the inner core layer has a density of 0.85 g/cm3 to about 1.1 g/cm3; wherein the inner core layer has a Shore D hardness cross-sectional hardness between any two points on the cross-section of within ±6; an outer core layer, the outer core substantially surrounding the inner core and comprising a thermoset rubber; and at least one cover layer; wherein the inner core has a compression deformation of from about 3.5 mm to about 4.1 mm, the outer core layer has a compression deformation of from about 2.7 mm to about 3.3 mm, and the outer core layer has a thickness of at least 4.8 mm, wherein compression deformation is measured as a difference between amount of deformation under a 10 kg load and amount of deformation under a 130 kg load; and wherein the golf ball has a first initial velocity measured at a club head speed of about 80 mph, the golf ball has a second initial velocity measured at a club head speed of about 125 mph, the initial velocities being otherwise measured under the same conditions, and the difference between the second initial velocity and the first initial velocity is at least about 86 mph, wherein the inner cover layer has a surface Shore D hardness of at least about 60 and the outer cover layer has a surface Shore D hardness of from about 50 to about 60, wherein the outer cover layer comprises a thermoplastic polyurethane crosslinked by reaction of unsaturated bonds provided by preparing the polyurethane polymer using an unsaturated diol of formula (1): wherein R1 is a substituted or unsubstituted alkyl group, substituted or unsubstituted aryl group, substituted or unsubstituted alkyl-aryl group, substituted or unsubstituted ether group, substituted or unsubstituted ester group, any of these optionally including an unsaturated bond, or H; R2 is a substituted or unsubstituted alkyl group, substituted or unsubstituted aryl group, substituted or unsubstituted alkyl-aryl group, substituted or unsubstituted ether group, substituted or unsubstituted ester group, and R2 includes an allyl group; and x and y are integers independently having any value from 1 to 10.