# US 8,784,236 B2 · Golf balls having dual cores made of polybutadiene rubber / ionomer blends > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,784,236 B2 - Document ID: US8784236B2 - Status: Granted - Kind: B2 - Application number: 13/029,795 - Filed: 2011-02-17 - Published: 2011-06-16 - Granted: 2014-07-22 - Earliest claimed: 2008-01-10 - Assignees: Acushnet Company - Applicants: Michael J. Sullivan; Derek A. Ladd - Inventors: Michael J. Sullivan; Derek A. Ladd - Web page: https://patentgrep.com/patent/US8784236B2 ## CPC - A63B 37/00922: {whereby hardness of the cover is lower than hardness of the intermediate layers} - A63B 37/0039: {characterised by the material} - A63B 37/0043: {Hardness} - A63B 37/0047: {Density; Specific gravity} - A63B 37/00621: {Centre hardness} - A63B 37/00622: {Surface hardness} - A63B 37/0065: {Deflection or compression} - A63B 37/0066: {Density; Specific gravity} - A63B 37/0075: {Three piece balls, i.e. cover, intermediate layer and core} - A63B 37/0076: {Multi-piece balls, i.e. having two or more intermediate layers} - A63B 37/0091: {Density distribution amongst the different ball layers} - A63B 37/0045: {Thickness} - A63B 37/0046: {Deflection or compression} - A63B 37/0064: {Diameter} - A63B: APPARATUS FOR PHYSICAL TRAINING, GYMNASTICS, SWIMMING, CLIMBING, OR FENCING; BALL GAMES; TRAINING EQUIPMENT (apparatus for passive exercising, massage A61H) ## Abstract A multi-piece golf ball comprising at least one component made of a polybutadiene rubber/ionomer resin blend is provided. The ball preferably contains a dual-core comprising an inner core and surrounding outer core layer. Preferably, the polybutadiene rubber/ionomer resin blend is used to form the outer core layer. The center hardness of the inner core is preferably greater than the outer surface hardness of the outer cover layer. The resulting ball has high resiliency and good impact durability. ## Claims ### Claim 1 A multi-piece golf ball, comprising: a dual-core comprising an inner core and outer core layer, the inner core having an outer surface and geometric center and the outer core layer having an outer surface and inner surface; the inner core being formed from a first rubber composition comprising polybutadiene rubber and ionomer resin, wherein the center of the inner core and surface of the outer core layer each has a hardness, and the center hardness of the inner core is greater than the surface hardness of the outer core layer; and a cover disposed about the outer core layer. ### Claim 2 (depends on 1) The golf ball of claim 1, wherein the specific gravity of the inner core is less than or equal to the specific gravity of the outer core layer. ### Claim 3 (depends on 1) The golf ball of claim 1, wherein the inner core has a specific gravity in the range of about 0.50 to about 1.20 g/cc. ### Claim 4 (depends on 1) The golf ball of claim 1, wherein the inner core has a specific gravity in the range of about 0.80 to about 1.18. ### Claim 5 (depends on 1) The golf ball of claim 1, wherein the inner core has a specific gravity in the range of about 0.90 to about 1.13 g/cc, and the outer core has a specific gravity in the range of about 1.00 to about 1.18 g/cc. ### Claim 6 (depends on 1) The golf ball of claim 1, wherein the center hardness of the inner core is in the range of about 51 to about 98 Shore C units and the surface hardness of the outer core is in the range of about 50 to 96 Shore C units. ### Claim 7 (depends on 6) The golf ball of claim 6, wherein the center hardness of the inner core and surface hardness of the out core are each greater than 80 Shore C units. ### Claim 8 (depends on 7) The golf ball of claim 7, wherein the center hardness of the inner core is in the range of about 82 to about 96 Shore C units and the surface hardness of the outer core is in the range of about 81 to about 95 Shore C units. ### Claim 9 (depends on 1) The golf ball of claim 1, wherein the center hardness of the inner core is at least 5 Shore C units greater than the surface hardness of the outer core layer. ### Claim 10 (depends on 1) The golf ball of claim 1, wherein the ionomer resin contains greater than 5 weight percent acid groups. ### Claim 11 (depends on 1) The golf ball of claim 1, wherein the ionomer resin contains greater than 11 weight percent acid groups. ### Claim 12 (depends on 10, 11) The golf ball of claim 10 or 11, wherein the acid groups of the ionomer resin are neutralized greater than 70%. ### Claim 13 (depends on 10, 11) The golf ball of claim 10 or 11, wherein the acid groups of the ionomer resin are neutralized greater than 90%. ### Claim 14 (depends on 1) The golf ball of claim 1, wherein the ionomer resin is a E/X/Y copolymer, wherein E is ethylene; X is a C3 to C8 α,β-ethylenically unsaturated mono- or dicarboxylic acid; and Y is a softening monomer. ### Claim 15 (depends on 14) The golf ball of claim 14 wherein the copolymer is selected from the group consisting of ethylene/(meth)acrylic acid/n-butyl acrylate; ethylene/(meth)acrylic acid/ethyl acrylate; ethylene/(meth)acrylic acid/methyl acrylate; ethylene/(meth)acrylic acid/n-butyl acrylate; and ethylene/(meth)acrylic acid/isobutyl acrylate copolymers. ### Claim 16 (depends on 1) The golf ball of claim 1, wherein the ionomer composition thither comprises a fatty acid or salt thereof. ### Claim 17 (depends on 1) The golf ball of claim 1, wherein the first rubber composition further comprises a polymer selected from the group consisting of polyesters; polyamides; polyamide-ethers, polyamide-esters; polyurethanes, polyureas; fluoropolymers; polystyrenes; polypropylenes and polyethylenes; polyvinyl chlorides; polyvinyl acetates; polycarbonates; polyvinyl alcohols; polyethers; polyimides, polyetherketones, polyamideimides; and mixtures thereof. ### Claim 18 (depends on 1) The golf ball of claim 1, wherein the outer core layer is formed from a second rubber composition comprising polybutadiene rubber. ### Claim 19 (depends on 1) The golf ball of claim 1, wherein the cover is formed from a composition comprising a polymer selected from the group consisting of polyesters; polyamides; polyamide-ethers, polyamide-esters; polyurethanes, polyureas; fluoropolymers; polystyrenes; polypropylenes and polyethylenes; polyvinyl chlorides; polyvinyl acetates; polycarbonates; polyvinyl alcohols; polyethers; polyimides, polyetherketones, polyamideimides; and mixtures thereof. ### Claim 20 (depends on 1) The golf ball of claim 1, wherein the cover comprises an inner cover layer and outer cover layer. ### Claim 21 A multi-piece golf ball, comprising: a multi-layered core comprising an inner core, intermediate core layer, and outer core layer, the core having an overall diameter of about 1.40 to about 1.62 inches, and the inner core being formed from a first rubber composition comprising polybutadiene rubber and ionomer resin and having a center hardness of 70 Shore C or greater, an intermediate core layer having a surface hardness of less than 80 Shore C; and an outer core layer having a surface hardness of 70 Shore C or greater, wherein the center hardness of the inner core is greater than the surface hardness of the outer core layer; and a cover disposed about the outer core layer. ### Claim 22 (depends on 21) The golf ball of claim 21, wherein the specific gravity of the inner core is less than or equal to the specific gravity of the outer core layer. ### Claim 23 (depends on 21) The golf ball of claim 21, wherein the specific gravity of the intermediate core layer is substantially the same as the specific gravity of the outer core layer. ### Claim 24 (depends on 21) The golf ball of claim 21, wherein the intermediate core layer and outer core layer each has a specific gravity in the range of about 1.00 to about 1.18 g/cc. ### Claim 25 (depends on 21) The golf ball of claim 21, wherein the cover comprises an inner cover layer and an outer cover layer.