Multi-layer golf ball providing improved speed

Abstract

The present invention is directed to a multi-layer golf ball comprising at least one core or core layer, at least one intermediate layer, and at least one cover layer. The core has a diameter of about 1.20 to about 1.56 in. and a PGA compression of about 40 to about 90. The intermediate layer comprises a modified ionomeric polymer, and it has a thickness of about 0.01 to about 0.10 in. and a Shore D hardness of about 30 to about 70. The cover layer has a Shore D hardness of about 40 to about 75. The multi-layer golf balls of the present invention provide high driver ball speed and/or a high Coefficient of Restitution, while maintaining excellent shot feel.

1 . A golf ball comprising: 
 a. a core;    b. an intermediate layer; and    c. a cover layer;    d. wherein said intermediate layer comprises a modified ionomeric polymer comprising: 
 i. a blend composition comprising: 
 (1) ethylene,  
 (2) 5 to 25 weight percent (meth)acrylic acid (based on the total weight of (1), (2), and (3)), and  
 (3) 0 to 40 weight percent of a C 1  to C 8 -alkyl acrylate (based on the total weight of (1), (2), and (3)), and  
 (4) about 5 to about 45 weight percent (based on the total weight of said modified ionomeric polymer), of a fatty acid or one or more metal salts of said fatty acid, or  
 
 ii. a bimodal polymer blend composition comprising: 
 (1) a high molecular weight component having molecular weight of about 80,000 to about 500,000 and comprising one or more ethylene/α,β-ethylenically unsaturated C 3-8  carboxylic acid copolymers and/or one or more ethylene, alkyl(meth)acrylate, (meth)acrylic acid terpolymers; said high molecular weight component being partially neutralized with metal ions selected from the group consisting of lithium, sodium, zinc, calcium, magnesium, and a mixture of any these, and  
 (2) a low molecular weight component having a molecular weight of about from about 2,000 to about 30,000 and comprising one or more ethylene/α,β-ethylenically unsaturated C 3-8  carboxylic acid copolymers and/or one or more ethylene, alkyl(meth)acrylate, (meth)acrylic acid terpolymers; said low molecular weight component being partially neutralized with metal ions selected from the group consisting of lithium, sodium, zinc, calcium, magnesium, and a mixture of any these, and  
 (3) about 5 to about 45 weight percent (based on the total weight of said modified ionomeric polymer) of a fatty acid or one or more metal salts of said fatty acid; or  
 
 iii. a combination of i. and ii.;  
 iv. wherein about 40 to 100 percent of the acid groups present in said modified ionomeric polymer are neutralized with zinc, sodium, lithium, calcium, or magnesium ions, or a combination thereof;  
   e. wherein said core has a diameter in the range of about 1.20 to about 1.56 in. and a PGA compression in the range of about 40 to about 90;    f. wherein said intermediate layer has a thickness in the range of about 0.01 to about 0.10 in. and a Shore D hardness in the range of about 30 to about 75;    g. and wherein said cover layer has a Shore D hardness in the range of about 40 to about 70.    
   
   
       2 . The golf ball of  claim 1 , wherein: 
 a. said core has a diameter in the range of about 1.40 to about 1.52 in. and a PGA compression in the range of about 40 to about 85;    b. said modified ionomeric polymer present in the intermediate layer comprises about 7 to about 35 weight percent (based on the total weight of said modified ionomeric polymer) of said one or more fatty acids or metal salts of a fatty acid, said metal being selected from the group consisting of calcium, sodium, zinc, lithium, magnesium, barium, and combinations thereof;    c. about 50 to 100 percent of the acid groups present in said modified ionomeric polymer present in the intermediate layer are neutralized with zinc, sodium, lithium, calcium, or magnesium ions, or a combination thereof;    d. said intermediate layer has a thickness in the range of about 0.02 to about 0.08 in and a Shore D hardness in the range of about 40 to about 70; and    e. said cover layer has a Shore D hardness in the range of about 45 to about 70.    
   
   
       3 . The golf ball of  claim 1 , wherein: 
 a. said core has a diameter of about 1.45 to about 1.50 in. and a PGA compression of about 40 to about 80;    b. the modified ionomeric polymer present in said intermediate layer comprises about 8 to about 20 weight percent (based on the total weight of the modified ionomeric polymer) of one or more or metal salts of stearic acid, said metal being selected from the group consisting of calcium, sodium, zinc, lithium, magnesium, barium, and combinations thereof;    c. about 70 to 100 percent of the acid groups present in said modified ionomeric polymer of said intermediate layer are neutralized with zinc, sodium, lithium, calcium, or magnesium ions, or a combination thereof;    d. said intermediate layer has a thickness in the range of about 0.03 to about 0.06 in., a Shore D hardness in the range of about 40 to about 65, and an average acid content of in the range of about 5 to about 25 weight percent; and    e. said cover layer has a Shore D hardness in the range of about 50 to about 70.    
   
   
       4 . The golf ball of  claim 1 , wherein said modified ionomeric polymer further comprises a zinc-neutralized ionomer of a polymer having the general formula E/X/Y, where E is ethylene, X is an alkyl(meth)acrylate present in an amount in the range of 0 to about 50 weight percent (based on the total weight of said zinc-neutralized ionomer), and Y is (meth)acrylic acid present in an amount in the range of about 5 to about 25 weight percent (based on the total weight of said zinc-neutralized ionomer).  
   
   
       5 . The golf ball according to  claim 1 , wherein said core comprises: 
 a. at least one unsaturated polymer;    b. at least one cross-linking agent; and    c. at least one co-cross-linking agent.    
   
   
       6 . The golf ball according to  claim 5 , wherein: 
 a. said unsaturated polymer has a Mooney viscosity (ML 1+4 (100° C.)) in the range of about 20 to about 80 and is selected from the group consisting of 1,2-polybutadiene, cis-1,4-polybutadiene, trans-1,4-polybutadiene, cis-polyisoprene, trans-polyisoprene, polychloroprene, polybutylene, styrene-butadiene rubber, styrene-butadiene-styrene block copolymer and partially and fully hydrogenated equivalents, styrene-isoprene-styrene block copolymer and partially and fully hydrogenated equivalents, nitrile rubber, silicone rubber, polyurethane, and combinations thereof; and    b. said cross-linking agent is present in an amount in the range of about 0.05 to about 5 parts by weight of the cross-linking agents per 100 parts by weight of the unsaturated polymer.    
   
   
       7 . The golf ball according to  claim 6 , wherein said core further comprises a peptizer comprising an organic sulfur compound, a metal salt of an organic sulfur compound, and/or a non-metal salt of an organic sulfur compound.  
   
   
       8 . The golf ball according to  claim 7 , wherein said core comprises: 
 a. a first cross-linking agent having a first characteristic decomposition temperature less than 150° C. for a t 1/2  equal to 0.1 hour; and    b. a second cross-linking agent having a second characteristic decomposition temperature greater than 150° C. for a t 1/2  equal to 0.1 hour.    
   
   
       9 . The golf ball according to  claim 8 , wherein the composition weight ratio of the first cross-linking agent to the second cross-linking agent is in the range of 5:95 to 95:5.  
   
   
       10 . The golf ball according to  claim 8 , wherein the composition weight ratio of the first cross-linking agent to the second cross-linking agent is in the range of 10:90 to 50:50.  
   
   
       11 . The golf ball according to  claim 6 , wherein said core further comprises an accelerator present in an amount in the range of about 0.1 to about 10 parts by weight per 100 parts by weight of said unsaturated polymer.  
   
   
       12 . The golf ball according to  claim 6 , wherein said core further comprises a filler selected from the group consisting of precipitated hydrated silica, limestone, clay, talc, asbestos, barytes, glass fibers, aramid fibers, mica, calcium metasilicate, barium sulfate, zinc sulfide, lithopone, silicates, silicon carbide, diatomaceous earth, carbonates such as calcium or magnesium or barium carbonate, sulfates such as calcium or magnesium or barium sulfate, metals, including tungsten steel copper, cobalt or iron, metal alloys, tungsten carbide, metal oxides, metal stearates, other particulate carbonaceous materials, and combinations thereof.  
   
   
       13 . The golf ball according to  claim 5 , wherein: 
 a. said unsaturated polymer is cis-1,4-polybutadiene and has a Mooney viscosity (ML 1+4 (100° C.)) in the range of about 30 to about 70; and    b. said cross-linking agent is present in an amount in the range of about 0.2 to about 3 parts by weight per 100 parts by weight of the unsaturated polymer.    
   
   
       14 . The golf ball according to  claim 13 , wherein said core further comprises a peptizer comprising: 
 a. an organic sulfur compound or metal salt of an organic sulfur compound, present in an amount in the range of about 0.01 to about 10 parts by weight per 100 parts by weight of the unsaturated polymer; or    b. a non-metal salt of an organic sulfur compound, present in an amount in the range of about 0.01 to about 10 parts by weight per 100 parts by weight of the unsaturated polymer.    
   
   
       15 . The golf ball according to  claim 13 , wherein said core further comprises an accelerator present in an amount in the range of about 0.2 to about 5 parts by weight per 100 parts by weight of the unsaturated polymer.  
   
   
       16 . The golf ball according to  claim 5 , wherein: 
 a. said unsaturated polymer is cis-1,4-polybutadiene and has a Mooney viscosity (ML 1+4 (100° C.)) in the range of about 35 to about 50; and    b. said cross-linking agent is present in an amount in the range of about 0.2 to about 2 parts by weight per 100 parts by weight of the unsaturated polymer.    
   
   
       17 . The golf ball according to  claim 16 , wherein said core further comprise a peptizer comprising: 
 a. pentachlorothiophenol, dibenzamido diphenyldisulfide, or a metal salt of pentachlorothiophenol, present in an amount in the range of about 0.10 to about 7 parts by weight per 100 parts by weight of the unsaturated polymer; or    b. an ammonium salt of pentachlorothiophenol, with the ammonium cation having the general cycloaliphatic or aromatic system, or a combination thereof, present in an amount in the range of about 0.1 to about 7 parts by weight per 100 parts by weight of the unsaturated polymer.    
   
   
       18 . The golf ball according to  claim 17 , wherein said peptizer is pentachlorothiophenol, or the zinc salt of pentachlorothiophenol, and is present in an amount in the range of about 0.15 to about 5 parts by weight per 100 parts by weight of said unsaturated polymer.  
   
   
       19 . The golf ball according to  claim 17 , wherein said peptizer is the NH 4   +  salt of pentachlorothiophenol, present in amount in the range of about 0.15 to about 5 parts by weight per 100 parts by weight of the unsaturated polymer.  
   
   
       20 . The golf ball according to  claim 16 , wherein said core further comprises an accelerator present in an amount in the range of about 0.5 to about 1.5 parts by weight per 100 parts by weight of the unsaturated polymer, and wherein the peptizer is selected from the group consisting of 2-mercaptobenzothiazole and a salt of 2-mercaptobenzothiazole.  
   
   
       21 . The golf ball according to  claim 5 , wherein said core comprises: 
 a. a first cross-linking agent having a first characteristic decomposition temperature less than 150° C. for a t 1/2  equal to 0.1 hour; and    b. a second cross-linking agent having a second characteristic decomposition temperature greater than 150° C. for a t 1/2  equal to 0.1 hour.    
   
   
       22 . The golf ball according to  claim 21 , wherein the composition weight ratio of the first cross-linking agent to the second cross-linking agent is in the range of 5:95 to 95:5.  
   
   
       23 . The golf ball according to  claim 21 , wherein the composition weight ratio of the first cross-linking agent to the second cross-linking agent is in the range of 10:90 to 50:50.  
   
   
       24 . The golf ball according to  claim 5 , wherein said cover layer comprises: 
 a. an ionomeric polymer comprising one or more E/X/Y copolymers, wherein E is ethylene, X is a C 3  to C 8  α,β ethylenically unsaturated carboxylic acid, and Y is a softening comonomer selected from the group consisting of alkyl acrylate and alkyl methacrylate, wherein the alkyl groups have from 1 to 8 carbon atoms, or ionomers of such E/X/Y copolymers, wherein X is in the range of about 5 to about 35 weight % of the E/X/Y copolymer and Y is in the range of 0 to about 50 weight % of the E/X/Y copolymer, and wherein the acid groups present in said ionomeric polymer are partially neutralized with a metal selected from the group consisting of zinc, sodium, lithium, calcium, magnesium, and combinations thereof; or    b. a bimodal ionomeric polymer comprising: 
 i. a high molecular weight component having a molecular weight in the range of about 80,000 to about 500,000 and comprising one or more ethylene/α,β-ethylenically unsaturated C 3-8  carboxylic acid copolymers and/or one or more ethylene, alkyl(meth)acrylate, (meth)acrylic acid terpolymers, wherein said high molecular weight component is partially neutralized with metal ions selected from the group consisting of lithium, sodium, zinc, calcium, magnesium, and combinations thereof, and  
 ii. a low molecular weight component having a molecular weight in the range of about 2,000 to about 30,000 and comprising one or more ethylene/α,β-ethylenically unsaturated C 3-8  carboxylic acid copolymers and/or one or more ethylene, alkyl(meth)acrylate, (meth)acrylic acid terpolymers, wherein said low molecular weight component is partially neutralized with metal ions selected from the group consisting of lithium, sodium, zinc, calcium, magnesium, and combinations thereof; or  
   c. a modified ionomeric polymer comprising: 
 i. a blend composition comprising: 
 (1) ethylene,  
 (2) 5 to 25 weight percent (meth)acrylic acid (based on the total weight of said modified ionomeric polymer), and  
 (3) 0 to 40 weight percent of a C 1  to C 8 -alkyl acrylate (based on the total weight of said modified ionomeric polymer), and  
 (4) about 5 to about 45 weight percent (based on the total weight of said modified ionomeric polymer) of a fatty acid or one or more metal salts of a fatty acid, or  
 
 ii. a bimodal polymer blend composition comprising: 
 (1) a high molecular weight component having a molecular weight in the range of about 80,000 to about 500,000 and comprising one or more ethylene/α,β-ethylenically unsaturated C 3-8  carboxylic acid copolymers and/or one or more ethylene, alkyl(meth)acrylate, (meth)acrylic acid terpolymers, wherein said high molecular weight component is partially neutralized with metal ions selected from the group consisting of lithium, sodium, zinc, calcium, magnesium, and combinations thereof,  
 (2) a low molecular weight component having a molecular weight in the range of about 2,000 to about 30,000 and comprising one or more ethylene/α,β-ethylenically unsaturated C 3-8  carboxylic acid copolymers and/or one or more ethylene, alkyl(meth)acrylate, (meth)acrylic acid terpolymers, wherein said low molecular weight component is partially neutralized with metal ions selected from the group consisting of lithium, sodium, zinc, calcium, magnesium, and combinations thereof, and  
 (3) about 5 to about 45 weight percent (based on the total weight of said modified ionomeric polymer) of a fatty acid or one or more metal salts of a fatty acid; or  
 
   d. combinations of a, b, and c.    
   
   
       25 . The golf ball of  claim 24 , wherein said cover layer further comprises a zinc-neutralized ionomer of a polymer having the general formula E/X/Y, where E is ethylene, X is an alkyl(meth)acrylate present in an amount in the range of 0 to about 50 weight percent (based on the total weight of said zinc-neutralized ionomer), and Y is (meth)acrylic acid present in an amount in the range of about 5 to about 25 weight percent (based on the total weight of said zinc-neutralized ionomer).  
   
   
       26 . The golf ball according to  claim 1 , wherein the ball has a coefficient of restitution greater than about 0.790, at 125 ft/sec inbound velocity.  
   
   
       27 . The golf ball according to  claim 1 , wherein one or more of said core, said intermediate layer, or said cover layer further comprises a polymer selected from the group consisting of thermoplastic elastomers, thermoset elastomers, synthetic rubber, thermoplastic vulcanizates, polycarbonate, polyolefin, polyamide, copolymeric polyamide, polyesters, polyvinyl alcohols, acrylonitrile-butadiene-styrene copolymers, polyarylate, polyacrylate, polyphenylene ether, impact-modified polyphenylene ether, high impact polystyrene, diallyl phthalate polymer, metallocene catalyzed polymers, styrene-acrylonitrile (SAN) (including olefin-modified SAN and acrylonitrile-styrene-acrylonitrile), styrene-maleic anhydride (S/MA) polymer, styrenic copolymer, functionalized styrenic copolymer, functionalized styrenic terpolymer, styrenic terpolymer, cellulose polymer, liquid crystal polymer (LCP), ethylene-propylene-diene terpolymer (EPDM), ethylene-vinyl acetate copolymers (EVA), ethylene-propylene copolymer, ethylene vinyl acetate, polyurea, and polysiloxane, or any metallocene-catalyzed polymers of these species.  
   
   
       28 . The golf ball according to  claim 1 , wherein said core comprises a center and one or more layers disposed around said center, and wherein the difference between the hardness of one layer and the next adjacent layer is greater than 2 Shore D units.  
   
   
       29 . The golf ball according to  claim 28 , wherein the hardness increases outwards, from the center to the outermost core layer.  
   
   
       30 . The golf ball according to  claim 28 , wherein the hardness decreases outwards, from the center to the outermost core layer.  
   
   
       31 . The golf ball according to  claim 28 , wherein the specific gravity increases outwards, from the center to the outermost core layer.  
   
   
       32 . The golf ball according to  claim 28 , wherein the specific gravity decreases outwards, from the center to the outermost core layer.  
   
   
       33 . The golf ball according to  claim 1 , wherein said core comprises a center and one or more layers disposed around said center, and wherein the difference between the specific gravity of one layer and the next adjacent layer is greater than 0.1.  
   
   
       34 . The golf ball according to  claim 1 , wherein said cover layer comprises: 
 a. an ionomeric polymer comprising one or more E/X/Y copolymers, wherein E is ethylene, X is a C 3  to C 8  α,β ethylenically unsaturated carboxylic acid, and Y is a softening comonomer selected from the group consisting of alkyl acrylate and alkyl methacrylate, wherein the alkyl groups have from 1 to 8 carbon atoms, or ionomers of such E/X/Y copolymers, wherein X is in the range of about 5 to about 35 weight % of the E/X/Y copolymer and Y is in the range of 0 to about 50 weight % of the E/X/Y copolymer, and wherein the acid groups present in said ionomeric polymer are partially neutralized with a metal selected from the group consisting of zinc, sodium, lithium, calcium, magnesium, and combinations thereof; or    b. a bimodal ionomeric polymer comprising: 
 i. a high molecular weight component having a molecular weight in the range of about 80,000 to about 500,000 and comprising one or more ethylene/α,β-ethylenically unsaturated C 3-8  carboxylic acid copolymers and/or one or more ethylene, alkyl(meth)acrylate, (meth)acrylic acid terpolymers, wherein said high molecular weight component is partially neutralized with metal ions selected from the group consisting of lithium, sodium, zinc, calcium, magnesium, and combinations thereof, and  
 ii. a low molecular weight component having a molecular weight in the range of about 2,000 to about 30,000 and comprising one or more ethylene/α,β-ethylenically unsaturated C 3-8  carboxylic acid copolymers and/or one or more ethylene, alkyl(meth)acrylate, (meth)acrylic acid terpolymers, wherein said low molecular weight component is partially neutralized with metal ions selected from the group consisting of lithium, sodium, zinc, calcium, magnesium, and combinations thereof; or  
   c. a modified ionomeric polymer comprising: 
 i. a blend composition comprising: 
 (1) ethylene,  
 (2) 5 to 25 weight percent (meth)acrylic acid (based on the total weight of said modified ionomeric polymer), and  
 (3) 0 to 40 weight percent of a C 1  to C 8 -alkyl acrylate (based on the total weight of said modified ionomeric polymer), and  
 (4) about 5 to about 45 weight percent (based on the total weight of said modified ionomeric polymer) of a fatty acid or one or more metal salts of a fatty acid, or  
 
 ii. a bimodal polymer blend composition comprising: 
 (1) a high molecular weight component having a molecular weight in the range of about 80,000 to about 500,000 and comprising one or more ethylene/α,β-ethylenically unsaturated C 3-8  carboxylic acid copolymers and/or one or more ethylene, alkyl(meth)acrylate, (meth)acrylic acid terpolymers, wherein said high molecular weight component is partially neutralized with metal ions selected from the group consisting of lithium, sodium, zinc, calcium, magnesium, and combinations thereof,  
 (2) a low molecular weight component having a molecular weight in the range of about 2,000 to about 30,000 and comprising one or more ethylene/α,β-ethylenically unsaturated C 3-8  carboxylic acid copolymers and/or one or more ethylene, alkyl(meth)acrylate, (meth)acrylic acid terpolymers, wherein said low molecular weight component is partially neutralized with metal ions selected from the group consisting of lithium, sodium, zinc, calcium, magnesium, and combinations thereof, and  
 (3) about 5 to about 45 weight percent (based on the total weight of said modified ionomeric polymer) of a fatty acid or one or more metal salts of a fatty acid; or  
 
   d. combinations of a, b, and c.    
   
   
       35 . The golf ball according to  claim 34 , wherein said cover layer further comprises a zinc-neutralized ionomer of a polymer having the general formula E/X/Y, where E is ethylene, X is an alkyl(meth)acrylate present in an amount in the range of 0 to about 50 weight percent (based on the total weight of said zinc-neutralized ionomer), and Y is (meth)acrylic acid present in an amount in the range of about 5 to about 25 weight percent (based on the total weight of said zinc-neutralized ionomer).