Golf Ball with Rubber Core, Layer, or Both and Method

Abstract

Golf ball comprising core, cover, and optional intermediate layer(s) has the core and/or intermediate layer(s) made by crosslinking a rubber composition including at least (a) 100 parts by weight polybutadiene having 85% to 100% cis-1,4 bond content; (b) about 10 to about 50 parts by weight of (i) a zinc, magnesium, or calcium salt of a first carboxylic acid with least two ethylenically unsaturated bonds and (ii) a zinc, magnesium, or calcium salt of a second carboxylic acid with one ethylenically unsaturated bond that is α,β to a carbonyl of a carboxyl group, wherein (b)(i) is about 50% by weight to 100% by weight of the combination of (b)(i) and (b)(ii); (c) a free radical initiator; and (d) an inorganic zinc, magnesium, or calcium compound. Further disclosed is a method of making this golf ball by molding and crosslinking the rubber composition to make the core or intermediate layer(s).

1 . A golf ball comprising a core, a cover, and optionally one or more intermediate layers between the core and the cover, wherein the core, one or a plurality of intermediate layers, or a combination thereof is formed by crosslinking a rubber composition comprising
 (a) 100 parts by weight of a polybutadiene having a cis-1,4 bond content of about 85% to 100%;   (b) from about 10 to about 50 parts by weight of (i) a zinc, magnesium, or calcium salt of a first carboxylic acid having at least two ethylenically unsaturated bonds and, optionally, (ii) a zinc, magnesium, or calcium salt of a second carboxylic acid having one ethylenically unsaturated bond that is α,β to a carbonyl of a carboxyl group, wherein (b)(i) is from about 50% by weight to 100% by weight of the combined weights of (b)(i) and (b)(ii);   (c) a free radical initiator; and   (d) an inorganic zinc, magnesium, or calcium compound.   
     
     
         2 . A golf ball according to  claim 1 , wherein the first carboxylic acid comprises at least two conjugated, ethylenically unsaturated bonds. 
     
     
         3 . A golf ball according to  claim 1 , wherein one of the ethylenically unsaturated bonds of the first carboxylic acid is conjugated with a carbonyl group. 
     
     
         4 . A golf ball according to  claim 1 , wherein the first carboxylic acid is a monocarboxylic acid, or (b)(ii) is present and the second carboxylic acid is a monocarboxylic acid, or both. 
     
     
         5 . A golf ball according to  claim 1 , wherein (b)(i) comprises a zinc salt of a linear carboxylic acid having at least 6 carbon atoms. 
     
     
         6 . (canceled) 
     
     
         7 . A golf ball according to  claim 1 , wherein (b)(ii) is present and comprises a member selected from the group consisting of zinc diacrylate, zinc dimethacrylate, and combinations thereof. 
     
     
         8 . A golf ball according to  claim 1 , wherein (b)(ii) is present and comprises zinc diacrylate and wherein the rubber composition further includes zinc stearate. 
     
     
         9 . A golf ball according to  claim 1 , wherein (b)(ii) is present and (b)(i) is from about 50% by weight to about 90% by weight of the combined weights of (b)(i) and (b)(ii). 
     
     
         10 - 12 . (canceled) 
     
     
         13 . A golf ball according to  claim 1 , wherein the inorganic compound (d) comprises zinc oxide. 
     
     
         14 . A golf ball according to  claim 1 , wherein the rubber composition comprises from about 2 to about 30 parts by weight of the inorganic compound (d). 
     
     
         15 - 19 . (canceled) 
     
     
         20 . A method of making a golf ball having a core, a cover, and, optionally, at least one intermediate layer between the core and the cover, comprising:
 forming a rubber composition comprising
 (a) 100 parts by weight of a polybutadiene having a cis-1,4 bond content of about 85% to 100% Y; 
 (b) from about 10 to about 50 parts by weight of (i) a zinc, magnesium, or calcium salt of a first carboxylic acid having at least two ethylenically unsaturated bonds and, optionally, (ii) a zinc, magnesium, or calcium salt of a second carboxylic acid having one ethylenically unsaturated bond that is α,β to a carbonyl of a carboxyl group, wherein (b)(i) is from about 50% by weight to 100% by weight of the combined weights of (b)(i) and (b)(ii); 
 (c) a free radical initiator; and 
 (d) an inorganic zinc, magnesium, or calcium compound; 
   molding and curing the rubber composition into a core, one or a plurality of intermediate layers, or a combination thereof; and   applying the cover.   
     
     
         21 . A method of making a golf ball according to  claim 20 , wherein the first carboxylic acid comprises at least two conjugated, ethylenically unsaturated bonds. 
     
     
         22 . A method of making a golf ball according to  claim 20 , wherein one of the ethylenically unsaturated bonds of the first carboxylic acid is conjugated with a carbonyl group. 
     
     
         23 . A method of making a golf ball according to  claim 20 , wherein the first carboxylic acid is a monocarboxylic acid, or (b)(ii) is present and the second carboxylic acid is a monocarboxylic acid, or both. 
     
     
         24 . A method of making a golf ball according to  claim 20 , wherein (b)(i) comprises a zinc salt of a linear carboxylic acid having at least 6 carbon atoms. 
     
     
         25 . (canceled) 
     
     
         26 . A method of making a golf ball according to  claim 20 , wherein (b)(ii) is present and comprises a member selected from the group consisting of zinc diacrylate, zinc dimethacrylate, and combinations thereof. 
     
     
         27 . A method of making a golf ball according to  claim 20 , wherein (b)(ii) is present and comprises zinc diacrylate and wherein the rubber composition further includes zinc stearate. 
     
     
         28 . A method of making a golf ball according to  claim 20 , wherein (b)(ii) is present and (b)(i) is from about 50% by weight to about 90%, by weight of the combined weights of (b)(i) and (b)(ii). 
     
     
         29 - 31 . (canceled) 
     
     
         32 . A method of making a golf ball according to  claim 20 , wherein the inorganic compound (d) comprises zinc oxide. 
     
     
         33 . A method of making a golf ball according to  claim 20 , wherein the rubber composition comprises from about 2 to about 30 parts by weight of the inorganic compound (d). 
     
     
         34 - 38 . (canceled)