Stearic-modified ionomers for golf balls
OwnerJohn Chu Cheninventor
Life of this patent
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Abstract
Ethylene/(meth)acrylic acid ionomers which have been modified with relatively low levels of a stearic acid moiety, particularly metal stearates and especially calcium stearate have improved resilience for a given level of hardness or PGA Compression values. The improvement is seen in bulk material when measurements are made on solid neat spheres. When used as cover material, the improvement is more manifest for softer material, and is less, or disappears, for typical mixed metal ionomer hard covers. The stearic-modified ionomers or ionomer blends are especially useful when the ionomer is formulated for use as a golf ball core, center, one-piece ball and as a soft golf ball cover. For covers, softer ionomer compositions will show an improvement.
Claims21
A golf ball cover composition comprising:
- (i) a blend comprising:
- (1) a terpolymer ionomer wherein the terpolymer comprises (a) ethylene, (b) an ethylenically unsaturated carboxylic acid present in an amount of from 5 to 25 wt % of the terpolymer, wherein the acid groups are from 10 to 90 percent neutralized with alkaline metals, alkaline earth metals and/or transition metals, including zinc, sodium, lithium, calcium, magnesium ions or a mixture of any of these, and (c) an alkyl acrylate present in an amount of from 1 wt % up to 40 wt % of the terpolymer;
- (2) an ethylene/unsaturated-carboxylic acid bipolymer which consists of a non-neutralized ethylene/unsaturated carboxylic acid bipolymer component having an acid content of up to 25%, based on the weight of the bi-polymer, and a neutralized ethylene/unsaturated carboxylic acid bipolymer component neutralized with alkaline metals, alkaline earth metals and/or transition metals, including zinc, sodium, lithium, calcium, magnesium ions or a mixture of any of these, wherein the neutralized bi-polymer is derived from the same bipolymer as the non-neutralized bipolymer, and,
- (ii) from 5 to 20 weight percent, based on (i) plus (ii), of a metal carboxylate having at least 12 carbon atoms, the metal selected from the group consisting of alkaline metals, alkaline earth metals and/or transition metals, including calcium, sodium, zinc, lithium, magnesium and barium or a mixture of said metal carboxylates,
- wherein the cover composition has a melt index (MI) of at least 0.5 dg/sec.
A golf ball cover composition comprising:
- (i) a blend comprising:
- (1) a terpolymer ionomer wherein the terpolymer comprises (a) ethylene, (b) an ethylenically unsaturated carboxylic acid present in an amount of from 5 to 25 wt % of the terpolymer, wherein the acid groups are neutralized with metals selected from the group consisting of alkaline metals, alkaline earth metals and/or transition metals, including zinc, sodium, lithium, calcium, magnesium ions or a mixture of any of these, and (c) an alkyl acrylate present in an amount of from 1 to 40 wt % of the terpolymer;
- (2) a neutralized ethylene/unsaturated carboxylic acid bipolymer having an acid content of up to 25%, based on the weight of the bipolymer, neutralized with alkaline metals, alkaline earth metals and/or transition metals, including zinc, sodium, lithium, calcium, magnesium ions or a mixture of any of these, and,
- (ii) from 5 to 20 weight percent, based on (i) plus (ii), of a metal stearate, the metal selected from the group consisting of alkaline metals, alkaline earth metals and/or transition metals, including calcium, sodium, zinc, lithium, aluminum, magnesium and barium or a mixture of said metal stearates,
- wherein the cover composition has a melt index (MI) of at least 0.5 dg/sec.
A golf ball cover composition comprising:
- (i) a blend comprising:
- (1) a terpolymer ionomer wherein the terpolymer comprises (a) ethylene, (b) an ethylenically unsaturated carboxylic acid present in an amount of from 5 to 25 wt % of the.terpolymer, wherein the acid groups are neutralized with zinc, sodium, lithium, calcium, magnesium ions or a mixture of any of these, and (c) an alkyl acrylate present in an amount of from 1 to 40 wt % of the terpolymer;
- (2) a non-neutralized ethylene/unsaturated carboxylic acid bipolymer having an acid content of up to 25%, based on the weight of the bipolymer and,
- (ii) from 5 to 20 weight percent, based on (i) plus (ii), of a metal stearate, the metal selected from the group consisting of alkaline metals, alkaline earth metals and/or transition metals, including calcium, sodium, zinc, lithium, aluminum, magnesium and barium or a mixture of said metal stearates,
- wherein the cover composition has a melt index (MI) of at least 0.5 dg/sec.
Dependencies are inferred from the claim text.