Extrusion method for making golf balls

Abstract

The present invention relates to a method for making golf balls by an extrusion molding process, particularly forming golf ball cores from an extrusion moldable composition. The present invention also relates to a golf ball having an extruded core, an outer cover layer and, optionally, one or more inner cover layers.

1 . A method for forming a golf ball core or core preform comprising extruding at least one extrusion-processable polymeric material or polymer precursor material through a die. 
     
     
         2 . The method according to  claim 1  where the core comprises a thermoplastic polymer. 
     
     
         3 . The method according to  claim 1  further comprising forming at least one additional layer about the core. 
     
     
         4 . The method according to  claim 3  comprising forming at least one cover layer having a cover composition comprising a reaction product of (a) diol(s), polyol(s), or combinations thereof; (b) diisocyanate(s), polisocyanate(s), or combinations thereof; (c) diamine(s), polyamine(s), or combinations thereof; or any combinations of (a), (b), and (c). 
     
     
         5 . The method according to  claim 3  further comprising forming an outer cover layer about the core. 
     
     
         6 . The method according to  claim 5  further comprising forming at least one intermediate layer disposed between the core and the outer cover layer. 
     
     
         7 . The method according to  claim 3  further comprising forming plural layers about the core by compression molding, injection molding, reaction injection molding, coating, casting, dipping, or combinations thereof. 
     
     
         8 . The method according to  claim 1  comprising extruding a first polymeric composition and subsequently modifying the composition. 
     
     
         9 . The method according to  claim 1  further comprising crosslinking an extruded core preform. 
     
     
         10 . The method according to  claim 1  comprising degassing the polymeric material or polymer precursor to produce a core or core perform substantially free of microvoids. 
     
     
         11 . The method according to  claim 1  where extruding comprises extruding material through a die to form disconnected 3-dimensional shapes. 
     
     
         12 . The method according to  claim 1  where the polymeric material is selected from the group consisting of ionomers, polyalkenamers, crosslinked polyalkenamers, synthetic rubbers, natural rubbers, thermoplastic polymers, and combinations thereof. 
     
     
         13 . The method according to  claim 12  where the thermoplastic material is selected from olefinic thermoplastic elastomers, metallocene catalyzed polymers, rubber-based thermoplastics, co-polyester thermoplastic elastomers, block copolymers comprising an aromatic vinyl group as a first block and a second block comprising a conjugated diene, polylamides, copolyamides, styrene block copolymers, functionalized styrenic block copolymers, polyesters, polyurethanes, ionomers, and combinations thereof. 
     
     
         14 . The method according to  claim 13  where the thermoplastic material is an ethylenically unsaturated thermoplastic elastomer. 
     
     
         15 . The method according to  claim 1  where the polymeric material further comprises a cross-linking agent selected from sulfur compounds, peroxides, azides, maleimides, e-beam radiation, gamma-radiation, a co-cross-linking agent comprising zinc or magnesium salts of an unsaturated fatty acid having from about 3 to about 8 carbon atoms, a base resin, a peptizer, an accelerator, a UV stabilizer, a photostabilizer, a photoinitiator, a co-initiator, an antioxidant, a colorant, a dispersant, a mold release agent, a processing aid, a fiber, a filler including a density adjusting filler, a nano-filler, an inorganic filler, an organic filler, and combinations thereof. 
     
     
         16 . The method according to  claim 3  further comprising forming a cover layer having a cover composition formed by a method comprising:
 mixing at least one component A that is a monomer, oligomer, prepolymer, or polymer comprising at least 5% by weight of anionic functional groups; at least one component B that is a monomer, oligomer, prepolymer, or polymer comprising less by weight of anionic functional groups than the weight percentage of anionic functional groups of the at least one component A; and at least one component C that is a metal cation, thereby forming a first composition; and 
 melt-processing the first composition to produce a reaction product of the anionic functional groups of the at least one component A and the at least one component C to form the polymer blend composition, wherein the polymer blend composition incorporates an in-situ-formed pseudo-crosslinked network of the at least one component A in the presence of the at least one component B. 
 
     
     
         17 . The method according to  claim 1 , further comprising:
 forming a composition comprising the at least one extrusion-processable polymeric material or the polymer precursor material;   extruding the golf ball core or ball core preform comprising the composition through the die; and   forming an outer cover layer about the core.   
     
     
         18 . The method according to  claim 17  wherein the core comprises at least one thermoplastic polymer. 
     
     
         19 . The method according to  claim 17  comprising forming the outer cover layer by compression molding, injection molding, reaction injection molding, coating, casting, dipping, or combinations thereof. 
     
     
         20 . The method according to  claim 17  where the polymeric material is selected from the group consisting of ionomers, polyalkenamers, crosslinked polyalkenamers, synthetic rubbers, natural rubbers, thermoplastic polymers, and combinations thereof. 
     
     
         21 . A method for forming a golf ball, comprising:
 forming a composition comprising at least one thermoplastic polymer or a polymer precursor material selected from the group consisting of ionomers, alkenomers, and combinations thereof;   extruding a golf ball core comprising the composition through a die;   forming at least one intermediate layer comprising a polymeric material about the core by compression molding, injection molding, reaction injection molding, coating, casting, dipping, or combinations thereof; and   forming an outer cover layer comprising a polymeric material about the core and intermediate layer by compression molding, injection molding, reaction injection molding, coating, casting, dipping, or combinations thereof.   
     
     
         22 . The method according to  claim 21  where extruding further comprises degassing the polymeric material to produce a core substantially free of microvoids. 
     
     
         23 . The method according to  claim 21  where the thermoplastic material is selected from olefinic thermoplastic elastomers, metallocene catalyzed polymers, rubber-based thermoplastics, co-polyester thermoplastic elastomers, block copolymers comprising an aromatic vinyl group as a first block and a second block comprising a conjugated diene, polylamides, copolyamides, styrene block copolymers, functionalized styrenic block copolymers, polyesters, polyurethanes, ionomers, and combinations thereof. 
     
     
         24 . The method according to  claim 21  where thermoplastic material of the core and/or the polymeric material of the at least one intermediate layer and the outer cover layer further comprises a cross-linking agent selected from sulfur compounds, peroxides, azides, maleimides, e-beam radiation, gamma-radiation, a co-cross-linking agent comprising zinc or magnesium salts of an unsaturated fatty acid having from about 3 to about 8 carbon atoms, a base resin, a peptizer, an accelerator, a UV stabilizer, a photostabilizer, a photoinitiator, a co-initiator, an antioxidant, a colorant, a dispersant, a mold release agent, a processing aid, a fiber, a filler including a density adjusting filler, a nano-filler, an inorganic filler, an organic filler, and combinations thereof. 
     
     
         25 . The method according to  claim 21  where the cover layer has a cover composition comprising a reaction product of (a) diol(s), polyol(s), or combinations thereof; (b) diisocyanate(s), polisocyanate(s), or combinations thereof; (c) diamine(s), polyamine(s), or combinations thereof; or any combinations of (a), (b), and (c). 
     
     
         26 . The method according to  claim 21  where forming an outer cover layer comprises forming a cover layer composition by a method comprising:
 mixing at least one component A that is a monomer, oligomer, prepolymer, or polymer comprising at least 5% by weight of anionic functional groups; at least one component B that is a monomer, oligomer, prepolymer, or polymer comprising less by weight of anionic functional groups than the weight percentage of anionic functional groups of the at least one component A; and at least one component C that is a metal cation, thereby forming a first composition; and 
 melt-processing the first composition to produce a reaction product of the anionic functional groups of the at least one component A and the at least one component C to form the polymer blend composition, wherein the polymer blend composition incorporates an in-situ-formed pseudo-crosslinked network of the at least one component A in the presence of the at least one component B. 
 
     
     
         27 . A golf ball comprising an extruded thermoplastic core material substantially free of microvoids and an outer cover layer comprising a polymeric material. 
     
     
         28 . The golf ball according to  claim 27  further comprising a least one intermediate cover layer comprising a polymeric material. 
     
     
         29 . The golf ball according to  claim 28  where a cover layer has a cover composition comprising a reaction product of (a) diol(s), polyol(s), or combinations thereof; (b) diisocyanate(s), polisocyanate(s), or combinations thereof; (c) diamine(s), polyamine(s), or combinations thereof; or any combinations of (a), (b), and (c).