# US 2014/0194226 A1 · Hollow core golf ball having a hardness gradient > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0194226 A1 - Document ID: US20140194226A1 - Status: Published application - Kind: A1 - Application number: 14/143,977 - Filed: 2013-12-30 - Published: 2014-07-10 - Earliest claimed: 2013-01-09 - Assignees: Acushnet Company - Applicants: Acushnet Company - Inventors: Michael J. Sullivan; Brian Comeau; Mark L. Binette - Web page: https://patentgrep.com/patent/US20140194226A1 ## CPC - A63B 37/0056: {Hollow; Gas-filled} - A63B 37/0027: {Polyurea} - A63B 37/0039: {characterised by the material} - A63B 37/0041: {Coefficient of restitution} - A63B 37/0043: {Hardness} - A63B 37/0045: {Thickness} - A63B 37/0061: {Coefficient of restitution} - A63B 37/00622: {Surface hardness} - A63B 37/0064: {Diameter} - A63B 37/0076: {Multi-piece balls, i.e. having two or more intermediate layers} - A63B 37/00776: {Slab hardness} - A63B 37/0092: {Hardness distribution amongst different ball layers} - A63B: APPARATUS FOR PHYSICAL TRAINING, GYMNASTICS, SWIMMING, CLIMBING, OR FENCING; BALL GAMES; TRAINING EQUIPMENT (apparatus for passive exercising, massage A61H) ## Abstract A golf ball including a hollow core formed from a spherical inner core shell layer including a stiff thermoplastic composition. The shell layer has an outer surface, an inner surface, and an inner diameter to define a hollow center. Ann outer core layer is disposed about the shell layer and includes a thermoset material. An inner cover layer is disposed about the outer core layer and includes an ionomeric material having a first hardness. An outer cover layer is disposed about the inner cover layer and includes a polyurethane having a second hardness different from the first. The hollow center has a diameter of 0.15 to 1.1 inches, the thermoplastic inner core shell layer has a hardness of 85 Shore C or greater, and the stiff thermoplastic composition has a melt volume flow rate of about 5.0 cm3/10 min or less at 230° C./2.16 kg. ## Claims ### Claim 1 A golf ball comprising a hollow core, the golf ball comprising: a spherical inner core shell layer formed from a stiff thermoplastic composition, the shell layer having an outer surface, an inner surface, and an inner diameter to define a hollow center; an outer core layer disposed about the shell layer, the outer core layer comprising a thermoset material; an inner cover layer disposed about the outer core layer, the inner cover comprising an ionomeric material and having a first hardness; and an outer cover layer disposed about the inner cover layer, the outer cover comprising a polyurea or a polyurethane and having a second hardness different from the first; wherein the hollow center has a diameter of about 0.15 to 1.1 inches, the thermoplastic inner core shell layer has a hardness of about 85 Shore C or greater, and the stiff thermoplastic composition has a melt volume flow rate of about 5.0 cm3/10 min or less at 230° C./2.16 kg. ### Claim 2 (depends on 1) The golf ball of claim 1, wherein the stiff thermoplastic composition has a melt volume flow rate of about 3.0 cm3/10 min or less at 230° C./2.16 kg. ### Claim 3 (depends on 2) The golf ball of claim 2, wherein the stiff thermoplastic composition has a melt volume flow rate of about 1.0 cm3/10 min or less at 230° C./2.16 kg. ### Claim 4 (depends on 1) The golf ball of claim 1, wherein the stiff thermoplastic inner shell layer comprises two pre-molded half shells. ### Claim 5 (depends on 1) The golf ball of claim 1, wherein the stiff thermoplastic inner shell layer is blow molded, rotationally molded, or gas injection molded. ### Claim 6 (depends on 1) The golf ball of claim 1, wherein the stiff thermoplastic composition has a hardness of about 90 Shore C or greater. ### Claim 7 (depends on 1) The golf ball of claim 1, wherein the outer core layer comprises a polybutadiene rubber and has a hardness equal to or less than the shell layer hardness. ### Claim 8 (depends on 1) The golf ball of claim 1, wherein the outer core layer has a thickness of about 0.025 inches to about 0.115 inches. ### Claim 9 (depends on 1) The golf ball of claim 1, wherein the golf ball further comprises an intermediate layer disposed between the outer core layer and the inner cover layer, the intermediate layer comprising a thermoset or thermoplastic material. ### Claim 10 (depends on 1) The golf ball of claim 1, wherein the second hardness is greater than the first. ### Claim 11 (depends on 1) The golf ball of claim 1, wherein the first hardness is greater than the second. ### Claim 12 (depends on 1) The golf ball of claim 1, wherein the golf ball has a first volume and the hollow center has a second volume that is about 2% to 30% of the first volume. ### Claim 13 (depends on 1) The golf ball of claim 1, wherein the spherical inner core shell layer has a coefficient of restitution less than about 0.700 when measured at an incoming velocity of 125 ft/s. ### Claim 14 (depends on 1) The golf ball of claim 1, wherein the outer core layer has a coefficient of restitution, measured at an incoming velocity of 125 ft/s, higher than the coefficient of restitution, measured at an incoming velocity of 125 ft/s, of the inner core shell layer by 10-50%. ### Claim 15 A golf ball comprising a hollow core, the golf ball comprising: a spherical inner core shell layer formed from a stiff thermoplastic composition, the shell layer having an outer surface, an inner surface, and an inner diameter to define a hollow center; an outer core layer disposed about the shell layer, the outer core layer comprising a thermoplastic material; an inner cover layer disposed about the outer core layer, the inner cover comprising an ionomeric material and having a first hardness; and an outer cover layer disposed about the inner cover layer, the outer cover comprising a polyurea or a polyurethane and having a second hardness different from the first; wherein the hollow center has a diameter of about 0.15 to 1.1 inches, the thermoplastic inner core shell layer has a hardness of about 85 Shore C or greater, and the stiff thermoplastic composition has a melt volume flow rate of about 5.0 or less cm3/10 min at 230° C./2.16 kg. ### Claim 16 (depends on 15) The golf ball of claim 15, wherein the outer core layer comprises a highly-neutralized ionomer and has a hardness equal to or less than the shell layer hardness. ### Claim 17 (depends on 15) The golf ball of claim 15, wherein the stiff thermoplastic composition has a melt volume flow rate of about 3.0 or less cm3/10 min at 230° C./2.16 kg. ### Claim 18 (depends on 17) The golf ball of claim 17, wherein the stiff thermoplastic composition has a melt volume flow rate of about 1.0 or less cm3/10 min at 230° C./2.16 kg. ### Claim 19 (depends on 15) The golf ball of claim 15, wherein the stiff thermoplastic inner shell layer comprises two pre-molded half shells. ### Claim 20 (depends on 15) The golf ball of claim 15, wherein the stiff thermoplastic inner shell layer is blow molded, rotationally molded, or gas injection molded.