Golf ball including a long-chain branched neodymium-catalyzed polybutadiene component

Abstract

The invention is directed to a golf ball comprising a long-chain branched neodymium-catalyzed polybutadiene having a cis-1,4 content of at least about 96% and a solution viscosity of less than 165 mPa·s, wherein the overall golf ball comprises a COR of at least about 0.780 and an Atti compression of from about 25 to about 120. The invention is also directed to a golf ball comprising a core, a cover and optionally an intermediate layer disposed between the core and the cover; wherein at least one of said core, cover and intermediate layer comprises a polybutadiene composition comprising a long-chain branched neodymium-catalyzed polybutadiene having a cis-1,4 content of at least about 96% and a solution viscosity of less than 165 mPa·s. In another embodiment, the golf ball comprises a core, a cover and optionally an intermediate layer disposed between the core and the cover; wherein said core comprises a polybutadiene composition comprising a long-chain branched neodymium-catalyzed polybutadiene having a cis-1,4 content of at least about 96% and a solution viscosity of less than 165 mPa·s.

Description

FIELD OF THE INVENTION[0001]This invention is directed to golf balls and methods for making golf balls incorporating materials which not only create desirable golf ball playing characteristics such as greater distance due to high COR, but also have broad application in targeting a wide range of compressions meanwhile possessing excellent processability in terms of quality of mix, extrudability, appearance (surface smoothness of extrudate), controlled cold flow, greater green strength, suitable tack and less backrinding, all thereby facilitating and reducing overall golf ball manufacturing costs.BACKGROUND OF THE INVENTION[0002]Golf balls are generally classified as either solid or wound. Solid golf balls are typically made with a solid core encased by a cover, both of which can have multiple layers, such as a dual core having a solid center and an outer core layer, or a multi-layer cover having an inner and outer cover layer. Additionally, one or more intermediate layers may be disp...

AI Technical Summary

Benefits of technology

[0016]High COR golf balls according to the invention incorporating a long-chain branched neodymium-catalyzed polybutadiene component (hereinafter referred to as “LCBNCP”) having a cis-1,4 content of at least about 96% and a solution viscosity of less than 165 mPa·s possess excellent golf ball processability and uniformity in product quality across a wide range of overall golf ball compressions. The LCBNCP may comprise at least one of the following: a long-chain branched neodymium-catalyzed polybutadiene; a long-chain branched neodymium-catalyzed polybutadiene composition including a long-chain branched neodymium-catalyzed polybutadiene; and a polybutadiene composition including the long-chain branched neodymium-catalyzed polybutadiene. The LCBNCP may also comprise blends of a long-chain branched neodymium-catalyzed polybutadiene, a long-chain branched neodymium-catalyzed polybutadiene composition and / or a polybutadiene composition.

[0017]The LCBNCP, having long-chain branches and exhibiting a smaller spacial extension in solution, demonstrates a lower solution viscosity than other neodymium-catalyzed polybutadiene compositions at a given molecular weight, Mooney Viscosity and polydispersity. This facilitates coordination between and movement among the various polymeric segments, thereby permitting great and controlled processability as well as particular compatability between the LCBNCP and other golf ball materials. Such processing characteristics include excellent quality of mix, extrudability, extrudate surface smoothness, controlled cold flow, greater green strength, suitable tack and less backrinding. Accordingly, manufacture / production of the golf ball of the invention is easier and less expensive.

[0044]In one embodiment, in any golf ball of the invention incorporating an LCBNCP having a cis-1,4 content of at least about 96% and a solution viscosity of less than 165 mPa·s, the appearance (surface smoothness of extrudate incorporating same), may be improved by up to about 75% over the appearance of extrudate including neodymium-catalyzed polybutadiene components having a solution viscosity of 165 mPa·s or greater.

[0046]In yet another embodiment, in any golf ball of the invention incorporating an LCBNCP having a cis-1,4 content of at least about 96% and a solution viscosity of less than 165 mPa·s, the green strength may be improved by up to about 50% over that of golf balls including neodymium-catalyzed polybutadiene containing golf ball components having a solution viscosity of 165 mPa·s or greater.

Problems solved by technology

Early solid golf balls lacked the softer feel, lower compression and higher spin rate of wound golf balls.

Although the compression of a ball alone does not determine whether a ball flies farther it can certainly influence or contribute to overall distance.

Controlled processability in golf ball materials remains an important consideration as processing difficulties translate to higher overall golf ball production costs.

Here, processing difficulties include both materials handling and manufacturing issues.

One handling concern is cold flow, often encountered with bales of uncured rubber during storage and shipment.

Poor extrudability, roughness of the extrudate, inconsistent quality of mix, insufficient degree of tack and backrinding, are additional processing / handling problems which golf ball manufacturers have faced in manufacturing golf balls with high COR within a wide range of compressions.

Regarding tack, a balance must be struck between a material having sufficient tack to adhere to another material, yet not possessing so much tack that it sticks to the mold for example, thereby interfering with molding operations.

Previous attempts to incorporate neodymium-catalyzed polybutadiene rubbers in high COR golf balls for a broad range of compressions have met processing difficulties.

However, the processing ability of the blend was found to decline as the amount of the highly linear neodymium-catalyzed polybutadiene in the blend was increased and the amount of the cobalt-catalyzed polybutadiene rubber was correspondingly reduced.