# US 2014/0194222 A1 · Golf ball having a hollow center > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0194222 A1 - Document ID: US20140194222A1 - Status: Published application - Kind: A1 - Application number: 13/736,993 - Filed: 2013-01-09 - Published: 2014-07-10 - Earliest claimed: 2013-01-09 - Assignees: Acushnet Company - Applicants: Acushnet Company - Inventors: Michael J. Sullivan; Mark L. Binette; Brian Comeau - Web page: https://patentgrep.com/patent/US20140194222A1 ## CPC - A63B 37/0056: {Hollow; Gas-filled} - A63B 37/0041: {Coefficient of restitution} - A63B 37/0044: {Hardness gradient} - A63B 37/0064: {Diameter} - A63B 37/0076: {Multi-piece balls, i.e. having two or more intermediate layers} - A63B 37/00776: {Slab hardness} - A63B 37/00921: {whereby hardness of the cover is higher than hardness of the intermediate layers} - A63B 37/0031: {Hardness} - A63B 37/0043: {Hardness} - A63B 37/0051: {Materials other than polybutadienes; Constructional details} - A63B 37/006: {Physical properties} - A63B 37/008: {Diameter} - 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 spherical inner core shell layer formed from a thermoset rubber composition, the shell layer having an outer surface, an inner surface, and an inner diameter to define a hollow center. A thermoplastic outer core layer is formed about the shell layer. An optional inner cover layer is formed about the outer core layer, the inner cover including an ionomeric material. An outer cover layer is formed over the core or option inner cover layer, the outer cover including a polyurea or a polyurethane and having a second hardness less than the optional inner cover layer. The hollow center has a diameter of about 0.15 to 1.1 inches. The shell layer has a surface hardness greater than its inner surface hardness by about 3 to 25 Shore C to define a hardness gradient, and the thermoplastic outer core layer has a second hardness gradient. ## Claims ### Claim 1 A golf ball comprising a hollow core, the golf ball comprising: a spherical inner core shell layer formed from a first thermoset rubber composition, the shell layer having an outer surface, an inner surface, and an inner diameter to define a hollow center; a thermoplastic outer core layer disposed about the shell layer; 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 less than the first; wherein the hollow center has a diameter of about 0.15 to 1.1 inches, the shell layer has a surface hardness greater than an inner surface hardness by about 3 to 25 Shore C to define a first hardness gradient, and the thermoplastic outer core layer has a second hardness gradient. ### Claim 2 (depends on 1) The golf ball of claim 1, wherein the shell layer has a surface hardness greater than about 55 Shore C. ### Claim 3 (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 4 (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 5 (depends on 1) The golf ball of claim 1, wherein the second hardness gradient is about 0 Shore C. ### Claim 6 (depends on 1) The golf ball of claim 1, wherein the second hardness gradient is a negative hardness gradient of about 1 to 10 Shore C. ### Claim 7 (depends on 1) The golf ball of claim 1, wherein the second hardness gradient is a positive hardness gradient of about 1 to 10 Shore C. ### Claim 8 (depends on 1) The golf ball of claim 1, wherein the inner cover has a hardness of greater than about 60 Shore D and the outer cover layer has a hardness of less than about 60 Shore D. ### Claim 9 (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 10 A golf ball comprising a hollow core, the golf ball comprising: a spherical inner core shell layer formed from a first thermoset rubber composition, the shell layer having an outer surface, an inner surface, and an inner diameter to define a hollow center; a thermoplastic outer core layer; a thermoplastic intermediate core layer disposed between the shell layer and the outer core layer; 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 less than the first; wherein the hollow center has a diameter of about 0.15 to 1.1 inches, the shell layer has a surface hardness greater than an inner surface hardness by about 3 to 25 Shore C to define a first hardness gradient, and the thermoplastic outer core layer or the thermoplastic intermediate core layer has a second hardness gradient. ### Claim 11 (depends on 10) The golf ball of claim 10, wherein the second hardness gradient is about 0 Shore C. ### Claim 12 (depends on 10) The golf ball of claim 10, wherein the second hardness gradient is a negative hardness gradient of about 1 to 10 Shore C. ### Claim 13 (depends on 10) The golf ball of claim 10, wherein the second hardness gradient is a positive hardness gradient of about 1 to 10 Shore C. ### Claim 14 A golf ball comprising a hollow core, the golf ball comprising: a spherical inner core shell layer formed from a first thermoset rubber composition, the shell layer having an outer surface, an inner surface, and an inner diameter to define a hollow center; a thermoplastic outer core layer; a thermoset intermediate core layer disposed between the shell layer and the outer core layer, the intermediate core layer comprising a second thermoset rubber composition different from the first; an inner cover layer disposed about the outer core layer, the inner cover comprising an ionomeric material and having a hardness greater than about 60 Shore D; and an outer cover layer disposed about the inner cover layer, the outer cover comprising a polyurea or a polyurethane and having a hardness less than about 60 Shore D; wherein the hollow center has a diameter of about 0.51 to 1.1 inches, the shell layer has a surface hardness greater than an inner surface hardness by about 3 to 25 Shore C to define a first hardness gradient, the thermoplastic outer core layer has a second hardness gradient, and the thermoset intermediate core layer has a third hardness gradient different from the first or second hardness gradients. ### Claim 15 (depends on 14) The golf ball of claim 14, wherein the shell layer has a surface hardness greater than about 55 Shore C. ### Claim 16 (depends on 14) The golf ball of claim 14, 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 17 (depends on 14) The golf ball of claim 14, 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 18 (depends on 14) The golf ball of claim 14, wherein the second hardness gradient is about 0 Shore C. ### Claim 19 (depends on 14) The golf ball of claim 14, wherein the second hardness gradient is a negative hardness gradient of about 3 to 25 Shore C. ### Claim 20 (depends on 14) The golf ball of claim 14, wherein the second hardness gradient is a positive hardness gradient of about 3 to 25 Shore C. ### Claim 21 (depends on 14) The golf ball of claim 14, 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.