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.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] Priority is claimed under 35 U.S.C. § 119(e) to U.S. Provisional Patent Application No. 60 / 572,432, filed on May 19, 2004, entitled “Multi-Layer Golf Ball Providing Improved Speed,” by Dean A. Snell, Hyun Jin Kim and Eric Loper, which application is incorporated by reference herein.BACKGROUND OF THE INVENTION [0002] This invention relates generally to golf balls, and, more specifically, to multi-layer golf balls. In particular, this invention relates to a golf ball having a core, at least one intermediate layer, and at least one cover layer, wherein the intermediate layer comprises an ionomer, or ionomer blend, and further comprises at least one fatty acid or metal salt thereof. The multi-layer golf balls of the present invention provide a higher ball speed and / or a higher coefficient of restitution (“C.O.R.”) than do analogous balls having an identical core and cover layer, but an intermediate layer made from the identical ionomers or ...

AI Technical Summary

Benefits of technology

[0027] The core preferably comprises a first cross-linking agent having a first characteristic decomposition temperature less than 150° C. for a t1/2 equal to 0.1 hour, and a second cross-linking agent having a second characteristic decomposition temperature greater than 150° C. for a t1/2 equal to 0.1 hour. The composition weight ratio of the first cross-linking agent to the second cross-linking agent is in the range of preferably 5:95 to 95:5, and more preferably 10:90 to 50:50.

[0028] The golf ball of the invention preferably has a coefficient of restitution greater than about 0.790, at 125 ft/sec inbound velocity. In addition, one or more of the core, the intermediate layer, and the cover layer preferably 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.

[0029] The core can comprise a center and one or more core layers disposed around such center. The difference between the hardnesses of one core layer and the next adjacent core layer is preferably greater than 2 Shore D units. This hardness difference can increase outwards, from the center to the outermost core layer. Alternatively, this hardness difference can decrease outwards, from the center to the outermost core layer. The difference between the specific gravity of one core layer and the next adjacent layer preferably is greater than 0.1, and more preferably is greater than 0.2. This specific gravity difference can increase outwards, from the center to the outermost core layer. Alternatively, this specific gravity difference can decrease outwa

Problems solved by technology

Moreover, because wound balls generally have a more complex structure, they generally require a longer time to manufacture and are more expensive to produce than are two-piece balls.

Further, such a combination imparts a high initial velocity to the ball, which results in increased distance.

Due to their hardness, however, these two-piece balls have a relatively low spin rate, which makes them difficult to control, particularly on relatively short approach shots.

Becau

Images