UNCOATED GOLF BALL

An uncoated golf ball may include a core, an ultraviolet dis-colorable cover about the core and having an exposed outermost surface and a stamp directly upon the outermost surface of the ultraviolet dis-colorable cover.

BACKGROUND

A golf ball may be subjected to ultraviolet light. To prevent the ultraviolet light from discoloring the golf ball, the golf ball is either provided with an outer cover that is resistant to ultraviolet degradation and/or the cover is painted or coated with at least one clear or pigmented coating that protects the cover from degradation due to ultraviolet light.

DETAILED DESCRIPTION OF EXAMPLES

Disclosed are example uncoated golf balls that may provide enhanced consistency and performance as compared to UV light protected golf balls. The example uncoated golf balls comprise covers formed from ultraviolet dis-colorable materials such as polyurethane and polyurea. Such materials may provide the uncoated golf ball with enhanced performance, such as enhanced velocity, spin rate and control. To further enhance the performance of such uncoated golf balls, the ultraviolet dis-colorable covers are neither coated nor painted, such as the cover for the outermost surface of the golf ball, leaving the outermost surface of the cover or a majority of the outermost surface exposed to the elements including ultraviolet light. Because the cover is neither coated nor painted, the uncoated golf balls are less susceptible to variations in the coating due to inconsistent paint or coating coverage. As a result, the uncoated golf balls provide enhanced flight consistency and accuracy.

In addition, the uncoated golf balls exhibit an increase in ball velocity as compared to coated or painted golf balls of the same composition. Moreover, at low swing speeds, the uncoated golf balls may provide increased spin rate. The increased spin rate may result from the coefficient of friction of the uncoated cover of the uncoated golf balls being greater than the otherwise painted or coated surface of a coated golf ball. The higher coefficient of friction may prevent the uncoated golf ball from exhibiting slippage on the clubface of short irons, which may result in increased spin rate and better green side performance.

Traditional golf balls are typically painted with multiple coats of paint and/or clear coating. Due to existing manufacturing processes, these multiple coats of paint are not evenly applied about the golf ball. As a result, unevenly applied coats of paint make the golf ball unbalanced, which can negatively effect the flight of the golf ball. An unbalanced golf ball will not fly as true as a balanced golf ball. The uncoated and unpainted golf balls of the present invention are not susceptible to this common cause of imbalance.

Disclosed is an example uncoated golf ball that comprises a core, an ultraviolet dis-colorable cover about the core and having an exposed outermost surface and a stamp directly upon the outermost surface of the one of the found the floor nice playing with it ultraviolet dis-colorable cover.

Disclosed is an example uncoated golf ball package that comprises a packaging and a plurality of uncoated golf balls within the packaging. Each of the plurality of uncoated golf balls may comprise a core and an ultraviolet dis-colorable cover having an exposed outermost surface about the core.

Disclosed is an example method for forming an uncoated golf ball. The method may comprise forming a cover about a core, wherein the cover has an outermost exposed surface formed from an ultraviolet dis-colorable material. The method may further comprise forming an identifier directly upon selected portions of the outermost surface of the cover.

FIG. 1is a sectional view of an example golf ball20. Golf ball20may provide enhanced consistency and performance as compared to UV light protected golf balls. Golf ball20has characteristics such that golf ball320satisfies the United States Golf Association (U.S.G.A.) golf ball standards, requirements or regulations.

Golf ball20comprises core22and an outermost cover30. Core22comprises extends about the spherical center of golf ball20. In the example illustrated, core22comprises a solid core in the form of a solid sphere centered within golf ball20. In other implementation, core22may comprise a wound core.

Cover30comprises a hollow spherical layer extending about core22. As schematically represented by ellipses, the hollow spherical region23between core22and cover30may take various forms. As we described hereafter, in some implementations, region23may be omitted such that core30directly contacts and is directly formed upon core22. In some implementations, region23may comprise an intermediate layer in the form of a mantle layer. In some implementations, region23may comprise multiple intermediate layers, such as an inner mantle layer and an outer mantle layer.

Cover30has an outermost surface32that also forms the outermost surface of golf ball20. At least a majority of the outermost surface32is exposed. For purposes of this disclosure, the term “exposed” with respect cover30or with respect to its outermost surface32means that surface32is uncovered, lacking any paints, coatings, films or other additional layers between outermost surface32and the surrounding air or environment. In the example illustrated, cover30comprises a homogenous layer of material, wherein the inner surface34of cover30is provided by the same material as the outermost surface32of cover30. The outermost surface32is a surface intended to be directly contacted and impacted by a golf club during play.

As further shown byFIG. 1, the outermost surface32of cover30comprises an array of dimples36across the entirety of the outermost surface32. Dimples32may have a variety of layouts or configurations. Dimples32may improve flight performance by reducing airflow resistance.

Cover30is formed from an ultraviolet dis-colorable material such as polyurethane, polyurea or mixtures thereof. In one implementation, such materials are cast about the remaining inner portions of golf ball20. Although softer and less durable as compared to Surlyn, such materials may offer enhanced spin while providing a desirable “feel” for highly skilled golfers. Although offering enhanced performance, such materials are also susceptible to discoloring in response to ultraviolet light. Such dis-colorization may be rapid; perceptible dis-colorization occurring within an individual round of golf. As a result, conventional golf balls that employ polyurethane or polyurea are painted or coated with at least one protective film or layer that protects the cover layer from ultraviolet light. The protective layer(s) may be in the form of at least one clear or pigmented coating that protects the cover from dis-colorization due to ultraviolet light. The protective layer maintains a consistent color on the ball surface and may contribute to scuff resistance of the ball.

In contrast to conventional wisdom regarding the use of ultraviolet dis-colorable materials such as polyurethane and polyurea, cover30of golf ball20is uncoated such that the outermost surface32of cover30is exposed. In the example illustrated, a majority of the outer circumferential area of cover32is exposed. In some implementations, the entirety of the outermost surface area of cover32is exposed.

It is been found that the conventional protective coating applied over the polyurethane or polyurea cover impairs performance. Because the outermost surface32of golf ball20is uncoated and at least a majority of which is exposed, golf ball20is less susceptible to variations in the coating due to inconsistent paint or coating coverage. As a result, golf ball20may provide enhanced flight consistency and accuracy.

In addition, golf ball20may exhibit an increase in ball velocity as compared to conventionally coated or painted golf balls of the same composition. Moreover, at low swing speeds, golf ball20may provide increased spin rate. The increased spin rate may result from the coefficient of friction of the uncoated cover30of golf ball20being greater than the otherwise painted or coated surface of a conventionally coated golf ball. The higher coefficient of friction may prevent golf ball20from exhibiting slippage on the clubface of short irons, which may result in increased spin rate and better green side performance.

In the example illustrated, the entirety of the outermost surface32of golf ball20is exposed but for an identifier, in the form of a stamp38which is formed or placed directly upon the outermost surface32of cover30. Stamp38may be in the form of a logo, number, source identifier and/or a ball type descriptor, which covers less than 50% of the outermost surface32of golf ball20. In some implementations, stamp38may additionally or alternatively comprise a line, arrow or other directional indicator to assist in putting alignment or the like which covers less than 50%. In some implementations, stamp38extends over less than 10% of the outermost surface32, and in many implementations, less than 5% of the outermost surface32of golf ball20.

Although identifier38is in the form of a stamp, in other implementations, the additional layer or layers of material forming identifier38may be applied in other manners. In some implementations, identifier38may be omitted. In some implementations, golf ball20may consist of core22, cover30, any intermediate layers (if any) between core22and cover30. In some implementations, golf ball20may consist of core22, cover30, any intermediate layers (if any) between core22and cover30, and one or more individual identifiers38directly formed on the outermost surface of the cover.

In one example implementation, core22may comprise a rubber core comprising a high-cis polybutadiene, a co-crosslinking agent, an activator, a free-radical initiator, optionally a fatty acid or metal salt of a fatty acid, an inert filler to adjust for weight and optionally a peptizer. In such an example implementation, cover30may comprise a cast polyurethane, polyurea material or mixtures thereof. In those example implementations in which region23is occupied by one or more intermediate mantle layers, the intermediate mantle layers may comprise material(s) from the group consisting of copolymer ionomers, terpolymer ionomers, fatty acid modified terpolymer ionomers (Dow HPF) and or mixtures thereof. In other implementations, the core22and/or intermediate mantle layer(s) may be far from other materials or compositions.

FIG. 2is a flow diagram of an example golf ball forming method100. Method100facilitates the forming of complete and final golf ball, ready for play, that may offer enhanced performance. Method100facilitates the forming of a complete and final golf ball that provides the performance benefits of a cover formed from an ultraviolet dis-colorable material such as polyurethane or polyurea while reducing or avoiding the discovered performance detractors associated with the protective coating conventionally applied over such a cover. Although method100is described in the context of forming golf ball20, it should be appreciated that method100may likewise be utilized for forming any of the following described golf balls or for forming other similar golf balls.

As indicated by block104, cover30is formed about core22. As disclosed above, cover30may be directly formed upon the outer circumferential surface of core22or may be formed upon the outermost referential service of an intermediate layer between core22and cover30. Cover30may be formed upon the outermost surface of multiple intermediate layers, such as upon the outermost surface of an outer mantle which itself extends about an inner mantle.

As further indicated by block104, cover30has an outermost surface32that is exposed and that is formed from an ultraviolet dis-colorable material such as polyurethane or polyurea. In other implementations, cover30may be formed from other ultraviolet dis-colorable materials. As disclosed above, because the outermost surface32of golf ball20is uncoated and at least a majority of which is exposed, golf ball20is less susceptible to variations in the coating due to inconsistent paint or coating coverage. As a result, golf ball20may provide enhanced flight consistency and accuracy.

In addition, golf ball20produced by method100may exhibit an increase in ball velocity as compared to conventionally coated or painted golf balls of the same composition. Moreover, at low swing speeds, golf ball20produced by method100may provide increased spin rate. The increased spin rate may result from the coefficient of friction of the uncoated cover30of golf ball20being greater than the otherwise painted or coated surface of a conventionally coated golf ball. The higher coefficient of friction may prevent golf ball20from exhibiting slippage on the clubface of short irons, which may result in increased spin rate and better green side performance.

As indicated by block106, and identifier, such as stamp38, is formed directly upon selected portions of the outermost surface32of the cover30. As described above, stamp38may be in the form of a logo, number, source identifier and/or a ball type descriptor, which covers less than 50% of the outermost surface32of golf ball20. In some implementations, stamp38may additionally or alternatively comprise a line, arrow or other directional indicator to assist in putting alignment or the like which covers less than 50%. In some implementations, stamp38extends over less than 10% of the outermost surface32, and in many implementations, less than 5% of the outermost surface32of golf ball20. Although identifier38is in the form of a stamp, in other implementations, the additional layer of material forming identifier38may be applied in other manners.

FIG. 3is a sectional view of an example uncoated golf ball package200. Package200comprises a packaging202containing a set of individual golf balls20-1,20-2and20-3(collectively referred to as golf balls20) golf balls20are each individually similar to golf ball20described above. Golf balls20are provided in packaging202, ready for commercial sale, wherein golf balls20may be withdrawn from package200for use in play. As disclosed above, in some implementations, golf ball20may omit the identifier38. In some implementations, identification information may be provided on packaging202.

In one implementation, package202encloses golf balls20in a manner so as to inhibit exposure of golf balls22ultraviolet light. As a result, packaging202reduces or eliminates this colorization of golf balls20as a result of exposure to ultraviolet light. In one implementation, packaging202is far from an opaque, light blocking panel or wall. In one implementation, packaging202blocks all of golf balls20from an exposure to ultraviolet light until the opening of packaging202.

FIG. 4is a cross-sectional view of golf ball320, an example implementation of golf ball20described above. Golf ball320is similar to golf ball20except that circumferential region23is empty with the size of core22being enlarged to occupy the space of region23. In the illustrated example, cover30is directly cast about and onto core22. Golf ball320has characteristics such that golf ball320satisfies the United States Golf Association (U.S.G.A.) golf ball standards, requirements or regulations. As described above with respect to golf ball20, the cover30of golf ball320has an ultraviolet dis-colorable cover having an outermost surface32that is exposed. In one implementation, a majority of the outermost surface32is exposed. In some implementations, as much as 90% and in some implementations as much as 95% of the outermost surface is exposed. In some implementations, the entirety of the outermost services exposed but for identifiers. The lack of an outermost coating over cover30provides enhanced flight consistency and accuracy. In addition, lack of an outermost coating over cover30may result in increased spin rate and better green side performance.

FIG. 5is a cross-sectional view of golf ball420, an example implementation of golf ball20described above. Golf ball420is similar to golf ball20except that circumferential region23is occupied by an intermediate layer or mantle424. In the illustrated example, cover30is directly cast about and onto mantle424. Golf ball420has characteristics such that golf ball320satisfies the United States Golf Association (U.S.G.A.) golf ball standards, requirements or regulations. As described above with respect to golf ball20, the cover30of golf ball420has an ultraviolet dis-colorable cover having an outermost surface32that is exposed. In one implementation, a majority of the outermost surface32is exposed. In some implementations, as much as 90% and in some implementations as much as 95% of the outermost surface is exposed. In some implementations, the entirety of the outermost services exposed but for identifiers. The lack of an outermost coating over cover30provides enhanced flight consistency and accuracy. In addition, lack of an outermost coating over cover30may result in increased spin rate and better green side performance.

FIG. 6is a cross-sectional view of golf ball520, an example implementation of golf ball20described above. Golf ball520is similar to golf ball20except that circumferential region23is occupied by multiple intermediate layers in the form of inner mantle524and outer mantle526. In the illustrated example, cover30is directly cast about and onto outer mantle526. Golf ball420has characteristics such that golf ball520satisfies the United States Golf Association (U.S.G.A.) golf ball standards, requirements or regulations. As described above with respect to golf ball20, the cover30of golf ball420has an ultraviolet dis-colorable cover having an outermost surface32that is exposed. In one implementation, a majority of the outermost surface32is exposed. In some implementations, as much as 90% and in some implementations as much as 95% of the outermost surface is exposed. In some implementations, the entirety of the outermost services exposed but for identifiers. The lack of an outermost coating over cover30provides enhanced flight consistency and accuracy. In addition, lack of an outermost coating over cover30may result in increased spin rate and better green side performance.

In one implementation, the core22of golf ball520has a diameter of 1.395 to 1.45 inches and comprises 100 phr of a neodymium-catalyzed high-cis polybutadiene, 26.5 to 27.5 phr of zinc diacrylate co-crosslinking agent, 5 phr zinc oxide, 5-7 phr stearic acid, 29 to 32 phr barium sulfate, 0.65 to 1 phr 1,1-Di(tert-butylperoxy)-3,3,5-trimethylcyclohexane, and 0 to 2 phr zinc pentachlorothiophenol. The core will have a compression (ADC) of about 50 to 55 and a deformation (Instron, 200 lb. load) of about 0.140″, and a weight of 28 to 29.5 grams. In one implementation, the inner matter layer524of golf ball520comprises a terpolymer of ethylene, acrylic acid and n-butyl acrylate, wherein the material contains a high amount of fatty acid which allow for 100% of the acid groups to be neutralized with a di-valent metal ion. Materials suitable for use in the example inner mantle524include HPF 1000 and HPF 2000 (manufactured by the Dow Chemical Company). The example inner mantle524has a thickness of 0.060 to 0.070 inches, has an outer diameter of 1.530 to 1.540 inches, a deformation of the core/inner mantle assembly under an applied load of 200 lb. of 0.110 to 0.130 inches (Instron deformation), a surface hardness (as measured on the curved surface of the inner mantle) of about 50 to 55 Shore D, and a weight of 35 to 36.5 grams.

In one example, the outer mantle526of golf ball520comprises an ionomer blend comprising a copolymer of ethylene and methacrylic acid having an acid content of 15% wherein 25 to 70% of the acid groups are neutralized with sodium ions and a copolymer of ethylene and methacrylic acid having an acid content of 15% wherein 40 to 70% of the acid groups are neutralized with zinc ions. Materials suitable use as the sodium portion of the outer mantle blend include Surlyn 8940, Surlyn 8945 and/or Surlyn 8920 (manufactured by the Dow Chemical company). Materials suitable for use as the zinc portion of the outer mantle include Surlyn 9910 and Surlyn 9945 (manufactured by the Dow Chemical Company). The outer mantle has a thickness of 0.045 to 0.55 inches, an outer diameter of 1.620 to 1.635 inches, a deformation of the core/inner mantle/outer mantle assembly under an applied load of 200 lb. of 0.080 to 0.100 inches (Instron deformation), a surface hardness (as measured on the curved surface of the outer mantle) of about 64 to 67 Shore D, and a weight of 41 to 42.5 grams.

In one example, cover30of golf ball520comprises a cast urethane material, the cast urethane material having a thickness of about 0.025 to 0.040″ and a hardness (as measure on the curved surface of the ball) of 78 to 82 Shore C.

In the example implementation, golf ball520is processed through normal finishing process (solvent wash, seam buffing, pre-paint finishing), but unlike conventional urethane covered golf balls the outer surface of the ball is not painted. The logo stamp is applied directly to the surface of the unpainted finished golf ball, and the ball is complete.

Example Golf Ball520:

The golf balls of the Example were made as follows:

A rubber core composition may be mixed using the following formula:

Solid golf ball core22of the above formula may be compression molded at a temperature of approximately 160° C. for approximately 7 minutes to produce a crosslinked core. After cooling, the core was glebarred (centerless ground) to a diameter of about 1.400″. The finished core had a weight of about 39.5 grams and a deflection, compressed using an Instron testing machine and compressed to measure the deformation of the ball under an applied load of 200 lb., of about 0.135 to 0.145 inches.

The inner mantle524of the example may be molded using HPF 1000 (manufactured by the Dow Chemical Company), which is a fatty-acid modified ionomer having 100% of the acid groups neutralized by a metal ion. The inner mantle (after molding) is glebarred to a diameter of 1.525 to 1.535 inches and has a thickness of ˜0.065 inches and a deformation under an applied load of 0.113 to 0.127 inches.

The outer mantle526of the example was molded using a blend of:

50% by weight of Surlyn 8940 (manufactured by the Dow Chemical Company), which is a copolymer of ethylene and methacrylic acid having about 29% of the acid groups neutralized with sodium ions, and

50% by weight of Surlyn 9910 (manufactured by the Dow Chemical Company), which is a copolymer of ethylene and methacrylic acid having about 58% of the acid groups neutralized with zinc ions.

The outer mantle526(after molding) is glebarred to a diameter of 1.625 to 1.635 inches and has a thickness of ˜0.050 inches and a deformation under an applied load of 0.093 to 0.107 inches.

The outer cover30of the example may be molded from a cast polyurethane composition, the outer cover of the molded ball having a thickness of about 0.025 to 0.030 inches and a surface hardness of about 80-82 Shore C.

Shore ‘D’ Hardness—Measured using Shore D durometer manufactured by Shore Instruments—Hardness reading measured on the surface of the golf ball

Compression: Compression testing is as measured using ADC compression tester produced by Automated Design Corporation, Bolingbrook, Ill. In an alternative method of measurement, the deformation of the ball can be measured under a 200 lb. static load, using an Instron compression testing machine produced by Instron Company, Norwood, Ma.

U.S.G.A. Initial Velocity—Measured according to U.S.G.A. Initial Velocity Test Protocol TPX3007, which is available on the U.S.G.A. website (U.S.G.A.org). The machine used for testing of U.S.G.A. Initial Velocity is the PTM3 C.O.R. machine, manufactured by Hye Precision Products, Perry, Ga. (Note: This is the machine on which the U.S.G.A. performs their Initial Velocity conformance testing.)

The golf ball of the Example exhibits the following physical properties compared to a control (paint coated) ball:Comparable ball compression (91.9 vs. 93.3).Significantly higher COR (0.010 to 0.011) compared to control (non-coated) ball.Significantly higher U.S.G.A. Initial Velocity (1.3 ft/s) compared to a non-coated ball.

The results of the test show the non-painted ball to have a surprisingly large increase in both C.O.R. and U.S.G.A. velocity compared to the non-coated ball.

TABLE 3Golf Ball Flight Performance Properties (Driver - 105 mph clubhead speed)CarryTotalLaunchMax.BallDist.Dist.AngleHeightS.A.A.VelocitySpinBall(yd.)(yd.)(°)(yd.)(sq. yd.)(mph)(rpm)Example26228512.733.477156.92880Wilson Staff ® Model26128412.534.6120156.32778cont.
Driver test at 105 mph was performed using a GolfLabs robot with the following setup conditions:Launch Angle—12.5°Spin Rate—2500 rpm
Flight properties were measured using TrackMan radar system.

The balls of the Example exhibited the following performance improvements compared to control balls at 105 mph Driver speed:Increase in ball velocity of 0.6 mph (0.88 ft/s).Increase in Driver spin rate of 3.7%.Decrease in S.A.A. (Statistical Area Accuracy—the area in which 95% of balls landed [carry distance] in flight test) of 36%.
As demonstrated by such results, non-painted urethane ball has increased ball velocity, higher spin rate and greater flight accuracy than control coated golf balls.

Driver test at 120 mph was performed using a GolfLabs robot with the following setup conditions:Launch Angle—9.5°Spin Rate—2200 rpm
Flight properties were measured using TrackMan radar system.

The balls of the Example exhibited the following performance improvements compared to control balls at 120 mph Driver speed:Increase in ball velocity of 1.0 mph (1.47 ft/s).Increase in Driver spin rate of 3.7%.Decrease in S.A.A. (Statistical Area Accuracy—the area in which 95% of balls landed [carry distance] in flight test) of 31%.

This test demonstrates that non-painted urethane ball has increased ball velocity, higher spin rate and greater flight accuracy than control coated golf balls.

TABLE 5Golf Ball Flight Performance Properties (9-iron)CarryTotalLaunchMax.BallDist.Dist.AngleHeightS.A.A.VelocitySpinBall(yd.)(yd.)(°)(yd.)(sq. yd.)(mph)(rpm)Example15115822.331.620111.18827Wilson Staff ® Model15015622.432.128110.88630cont.
9-iron test performed Driver test at 81 mph was performed using a GolfLabs robot with the following setup conditions:Launch Angle—22°Spin Rate—9000 rpm
Flight properties were measured using TrackMan radar system.

The balls of the Example exhibited the following performance improvements compared to control balls on 9-iron club:Increase in ball velocity of 0.3 mph (0.44 ft/s).Increase in 9-iron spin rate of 2.3%.Decrease in S.A.A. (Statistical Area Accuracy—the area in which 95% of balls landed [carry distance] in flight test) of 29%.

Driver and 9-iron testing show that the performance of the non-coated ball of the Example exhibits higher ball speed, higher spin rate and greater level of accuracy (lower Statistical Area Accuracy). The performance indicates that the ball of the Example will provide performance improvements as needed for the best golfers.