GB2144045A

GB2144045A - Golf ball

Info

Publication number: GB2144045A
Application number: GB8418699A
Authority: GB
Inventors: Terence Melvin; Dennis R Nesbitt
Original assignee: Questor Corp
Current assignee: Questor Corp
Priority date: 1983-08-01
Filing date: 1984-07-23
Publication date: 1985-02-27
Also published as: GB2144045B; AU555564B2; GB8418699D0; JPS6040071A; AU2187783A; CA1256231A

Abstract

A golf ball, comprises at its surface a polymeric material which is pigmented white, and includes an optical brightener.

Description

SPECIFICATION Golf ball This invention is concerned with golf balls technology. In accordance with this invention, appearance (e.g. color) of a golf ball is enhanced by use of an original brightener in combination with a pigment system, thereby eliminating the need for a supplemental paint coating. The golf ball can be superior to prior art painted golf balls in both color and optical brightness.

Golf balls are of two types, these types being solid balls and multicomponent balls. The solid ball comprises a polymeric sphere into which is molded a plurality of dimples to aid the flight characteristic of the ball. The multicomponent ball comprises a wound or solid core which is covered with a separate and distinct cover. The present invention is concerned primarily with the latter-mentioned multicomponent type golf balls and a means for enhancing the color of the covers in question. However, the invention can be used with the solid balls as described above.

Golf ball covers have, for decades, consisted principally of balata, a natural resin. In the last twenty years, synthetic polymeric materials and mixtures thereof have come into widespread usage as golf ball covers. With both balata covers and synthetic polymeric golf ball covers, a final multicoat paint system has been utilized in order to give the finished product a white durable finish. In their natural form, neither the above-mentioned balata nor synthetic polymeric materials are white in appearance. In order to provide a white base for the paint system as used in the prior art, it was very common to blend a white pigment (see below) into the cover composition. Regardless of this utilization of a white pigment, it was still necessary to utilize the paint system as described above in order to produce a top-quality white golf ball suitable for professional play.The painting of the pigmented cover is necessary as even with the white pigment the resulting cover is not a bright white.

Over sixty years ago, balata came into widespread usage as a golf ball cover composition.

Balata is a natural resin, and is off white in its natural state when applied as a golf ball cover. It was soon realized that it would be desirable to have a bright white golf ball in order to enhance the aesthetics of the ball and its visibility during play. In order to achieve these ends, pigmentation of the balata golf ball cover material became common practice. A plurality of white pigments was utilized in the early development of the golf ball. In recent years, titanium dioxide became the most prevalent pigment for use in golf ball cover compositions. Regardless of the use of titanium dioxide and other pigments in golf ball cover compositions, it became apparent that a truly white golf ball could not be produced by pigmentation alone. In order to enhance the whiteness of the finished golf ball, at an early date it was decided to paint pigmented golf ball covers.To achieve the desired appearance, it was necessary to utilize a multicoat paint system. This multicoat paint system is expensive and undesirable in the sense that once the paint chips during play, the ball in question becomes unsightly in that the cover material becomes visible. This cover material has a different color from the painted surface. In most instances, the cover stock material is a different shade of white as compared to the white paint.

These differences in color result in an unsightly ball having a used appearance once the paint chips. The use of a multicoat paint system over a pigmented cover stock continues to date.

Starting in the mid-1 960's and increasing rapidly in the early 1 970's, synthetic polymeric compositions came into widespread usage as golf ball cover materials. Polyurethanes, polyethylene, and ionic copolymers have been utilized as golf ball cover materials. In most instances, the synthetic polymeric materials are clear or amber color and, as such, the pigmentation and painting as described above in conjuction with balata covered balls is even more important. A series of polymers, either singularly or in mixtures, as sold by the E.l. DuPont de Nemours 8 Co., of Wilmington, Delaware, under the registered trademark SURLYN have become particularly important as golf ball cover materials in the last decade. At the present, these Surlyn materials are the most widely used cover materials for golf balls.

Typically, a golf ball cover composition comprises a synthetic or natural polymeric base to which is added a pigment in the amount of approximately 2% as based on the weight of the polymeric material. In recent years, titanium dioxide has become the most widely used pigment.

In addition to the pigment, the cover composition can contain additional ingredients to retard oxidation and compositions to improve the processing characteristics of the overall mixture.

Prior to this invention, it was not possible to achieve a top-grade, white golf ball without the use of a supplemental paint system. These supplemental paint systems are very expensive and difficult to apply in that the paints themselves are expensive and they must be applied to a small spherical surface. Multicoat paint systems are commonly used which included one or more coats of a pigmented paint followed by, in many instances, clear coats.

A first aspect of the present invention provides a golf ball, comprising: (a) polymeric material which is pigmented white, wherein: the surface of said pigmented polymeric material has optical properties affected by an optical brightener, said pigmented polymeric material optionally being comprised by a golf ball cover composition; and (b) a said optical brightener affecting said optical properties.

A second aspect of the present invention provides a golf ball cover composition suitable for use in manufacturing a golf ball according to said first aspect of the present invention, said composition comprising: polymeric material which is pigmented white; and an optical brightener.

The present invention can be embodied in any suitable manner, e.g. can be in accordance with any of the claims appended to this specification.

In contrast to the prior art painted golf balls, by use of the present invention, a superior golf ball can be produced in the complete absence of a finished painted surface. The present invention enhances the optical appearance of e.g. a resulting cover composition in order to give it a superior white appearance.

Because they are cheaper and have superior processing characteristics, thermoplastic materials are generally preferred for use as cover materials in accordance with this invention. However, thermosetting resins can likewise be used in accordance with this invention. Typical, but not limitative of the properties desirable for the resins, are good flowability, moderate stiffness, high abrasion resistance, high tear strength, high resilience, and good mold release, among others.

Preferred polymeric materials for use in accordance with this invention are ionomer resins comprising a copolymer of ethylene and an unsaturated monocarboxylic acid which are available under the registered trademark Surlyn from E.I. DuPont de Nemours 8 Company of Wilmington, Delaware.

In accordance with a preferred embodiment of this invention, a golf ball cover can be formed from either a zinc or sodium ionic copolymer of ethylene or mixtures thereof. The sodium copolymer is sold by the E.l. DuPont de Nemours 8 Company, Inc., under the registered trademarks Surlyn 1605/8940. The zinc copolymer is sold under the registered trademarks Surlyn 1557/9650, and Surlyn 1706/9910.

The use of singular ionic copolymers of polyethylene materials as golf ball cover stock is described in U.S. Patent No. 3,454,280 issued July 8, 1 969. Mixed Surlyn resins suitable for use in accordance with said preferred embodiment are described in great detail in U.S. Patent No. 3,819,768 issued June 25, 1974. Some ionic copolymers suitable for use in the present invention are further described in great detail in U.S. Patent No. 3,264,272 issued August 2, 1966.

This invention can be used in conjunction with cellular polymeric golf ball covers as are described in U.S. Patent No. 4,274,637 issued June 23, 1981.

In addition to the above-described preferred Surlyn resins, natural polymeric materials may be used in accordance with this invention. Balata or gutta percha is an example of natural polymeric material adapted for use in accordance with this invention.

The range of synthetic polymeric materials which can be used in accordance with this invention, other than the above-described Surlyn resins, is much broader than the range of natural materials. Some polymeric materials suitable for use in this invention are as follows: Homopolymeric and copolymeric substances, such as: (1) vinyl resins formed by the polymerization of vinyl chloride or by the copolymerization of vinyl chloride with unsaturated polymerizable compounds, e.g., vinyl esters; (2) polyolefins such as polyethylene, polypropylene, polybutylene, transpolyisoprene, and the like, and copolymers of polyolefins; (3) polyurethanes such as are prepared from polyols and organic polyisocyanates; (4) polyamides such as poly (hexamethylene adipamide); (5) polystyrene, high impact polystyrene, styrene acrylonitrile copolymer and ABS, which is acrylonitrile, butadiene styrene copolymer; (6) acrylic resins as exemplified by the copolymers of methylmethacrylate, acrylonitrile, and styrene, etc.; (7) thermoplastic rubbers such as the urethanes, copolymers of ethylene and propylene, and transpolyisoprene, block copolymers of styrene an cispolybutadiene, etc.; and (8) polyphenylene oxide resins, or a blend with high impact polystyrene known by the trade name "Noryl". This list is not meant to be limiting or exhaustive, but merely illustrates the wide range of polymeric materials which may be employed in the present invention. Mixtures of the above-described materials may also be used.

It is within the purview of this invention to add useful compatible materials to cover compositions used in this invention, e.g. antioxidants, antistatic agents, and stabilizers.

As can be seen from the discussion above, the present invention can be used in conjunction with a wide variety of polymeric materials which are suitable for the formation of covers.

The white basic color of a golf ball cover is formed by the pigmentation of one of the abovementioned polymeric materials. Some suitable pigments for use in accordance with the present invention are: titanium dioxide; zinc oxide; and zinc sulfide.

The amount of pigment used in conjunction with the polymeric cover composition depends on the particular polymeric material utilized and the particular pigment utilized. The concentration of the pigment in the polymeric cover composition can be from substantially 1 % to substantially 10% as based on the weight of the polymeric material. A more preferred range is from substantially 1% to substantially 5% as based on the weight of the polymeric material. The most preferred range is from substantially 1% to substantially 3% as based on the weight of the polymeric material.

The most preferred cover compositions for use in accordance with the present invention comprises the Surlyn resins as are descried above. The most preferred pigment for use in accordance with the present invention is titanium dioxide. When this combination of components is utilized, it is preferred that the concentration of titanium dioxide in the cover composition be from substantially 1% to substantially 10% as based on the weight of Surlyn resin utilized. A more preferred range for the concentration of titanium dioxide is from substantially 1% to substantially 5% as based on the Surlyn resin utilized. A most preferred concentration for the titanium dioxide is substantially 2% as based on the weight of the Surlyn resin utilized.

The present invention is adapted to utilize a wide variety of optical brighteners. The optical brightener utilized must be compatible with the polymer which is used as a base cover stock and with the pigment used therein. Some specific examples of suitable optical brighteners which can be used in accordance with the present invention will now be mentioned. Uvitex OB as sold by the Ciba-Geigy Chemical Company, Ardsley, New York. While the exact composition of Uvitex OB is proprietary to Ciba-Geigy, it is said to be a bis(benzoxyazoyl) derivative. Leucopure EGM as sold by Sandoz, East Hanover, New Jersey 07936. Leucopure is thought to be 7-(2h naphthol(1 ,2-d)-triazol-2-yl)-3-phenyl-coumarin. Phorwhite K-2002 as sold by Mobay Chemical Corporation, P.O. Box 385, Union Metro Park, Union, N.J. 07083. Phorwhite K-2002 is thought to be pyrazoline derivative.

The percentage of optical brightener which can be used in accordance with the present invention can be from substantially 0.001% to substantially 0.5% as based on the weight of the polymer used as a cover stock. A more preferred range is from substantially 0.01% to substantially 0.2%, with the most preferred range being from substantially 0.01% to substantially 0.1%.

One preferred cover composition for use in accordance with this invention consists of 46.31 parts of sodium ionic copolymer, as sold under the trademark Surlyn 1605/8940; 7.3 parts of a zinc ionic copolymer as sold under the trademark Surlyn 1557/9650; 46.31 parts of a zinc ionic copolymer as sold under the trademark Surlyn 1706/9910; 2.3% of titanium dioxide, 0.1% of Uvitex OB and Ultramarine Blue. The percentages of titanium dioxide and Uvitex OB are based on the combined weight of sodium and zinc ionic copolymers.

Covers for use in accordance with this invention can be injected molded onto a prepositioned core in accordance with injection molding techniques commonly known in the prior art.

Likewise, covers on finished golf balls can be produced by forming, by injection molding techniques, cover half shells two of which are then positioned around a golf ball core. The core with the preformed half shells thereon is then positioned in a compression mold and two half shells are fused together, and dimples formed thereon in accordance with procedures commonly known in the prior art.

As has been discussed above, the present invention can utilize a wide variety of polymers.

When pigmented, many of the polymers in question, and in particular, Surlyn resins, are not glossy after injection molding. Experience has demonstrated that the average golfer prefers a glossy golf ball. In order to produce glossy golf balls, golf balls of the present invention can be coated with a clear epoxy-urethane system subsequent to formation. That system comprises a clear epoxy primer, followed by a clear urethane coat. Use of this clear coat system subsequent to the molding operation is not mandatory in order to achieve desirable results of the present invention. However, it is highly desirable. In addition to high initial gloss, the above-mentioned system produces a golf ball which is durable and maintains its gloss during play. It is understood by one skilled in the art that other clear coated systems can likewise be utilized.

Further, it is understood the use of a clear coat system is not mandatory in accordance with this invention.

One qualification for the optical brightener used in accordance with this invention is the optical brightener must be compatible with the polymer system utilized. The optical brightener must be stable at temperatures necessary to injection molding the golf ball cover onto a prepositioned core if the above-described injection molding technique is utilized. If the compression molding technique is used in the formation of the golf ball, the optical brightener used in accordance with the present invention must be stable at the temperature necessary for the injection molding of the cover half shell and the compression molding of the cover half shells around a preformed core.

The present invention will now be illustrated by the following Examples, wherein Examples 1 to 4 are of the present invention, and Example 5 is a comparative Example.

In the Examples, finished golf balls were prepared by positioning preformed polybutadiene cores in an injection molding cavity. The cores were centrally positioned in the cavities by the use of retractable pins. A cover was injection molded around the core in question.

Example 1 Using the procedures described above, twelve golf balls were prepared wherein the cover had the following composition: Surlyn 1605/8940 46.31 parts by weight Surlyn 1706/9910- 46.31 II " II Surlyn 1557-9650 7.38 w II Titanium dioxide 2.34 " n II Ultramarine Blue 0.012 " Uvitex OB 0.102 " " " The resulting golf ball was removed from the injection mold cavity. The balls had a white appearance and when tested using a Hunter-Lab Colorimeter gave the following coverage values: Reflectance Number: 83.21 (as tested in accordance with standard procedures).

Whiteness Index: 141.18 (as tested in accordance with ASTM E-313-73).

Yellowness Index: - 20.25 (as tested in accordance with ASTM D-1925-70).

The Surlyn resins as used in these Examples are a product of the E.l. DuPont de Nemours e Co., Inc. in accordance with the description herein above.

The Uvitex OB is a product of the Ciba-Geigy Chemical Company in accordance with the description herein above.

Ultramarine Blue is a blue dye as sold by Whitaker, Clark and Daniels, of South Plainsfield, N.J.

Example 2 The procedure described in Example 1 was repeated, except that the balls were finished conventionally with a commercial two-coat, clear finish as follows: 1st coat-clear epoxy TCL 3631/3707-0.055 gm/ball net weight 2nd coat-clear urethane TCL 2119/2061---0.07 gm/ball net weight The average optical properties for these balls were: Reflectance Number: 81.32 Whiteness Index: 113.97 Yellowness Index: - 12.78 The TCL paints as used in this Example are sold by the Technical Coating Laboratories of Avon, Connecticut.

Example 3 Sample slabs of golfs ball material were formed, and tested in accordance with the procedure described in Example 1. In Example 3, the sample slabs had the following composition: Surlyn 1605/8940 46.31 parts by weight Surlyn 1706/9910 46.31 " " V? Surlyn 1557/9650 7.38 ?? n II Titanium dioxide 2.54 " " ' Ultramarine Blue 0.012 " " " Phorwhite K-2002 0.102 " " " The resulting slabs had a white appearance. Visual examination of the samples indicated that the optical properties of the samples were similar to those of the golf ball covers of Example 1.

Phorwhite K-2002 is sold by the Mobay Chemical Corporation in accordance with the description herein above.

Example 4 Sample slabs of golf ball cover material were formed, and tested in accordance with the procedure described in Example 3. In Example 4, the cover had the following composition: Surlyn 1605/8940 46.31 parts by weight Surlyn 1706/9910 46.31 " II IV Surlyn 1557-9650 7.38 n " " Titanium dioxide 2.34 " II VI Ultramarine Blue 0.012 " " " Leucopure EGM 0.102 " " VI Again, the resulting sample slabs had a white appearance and had optical properties which were similar to the golf balls covers of Example 1. Leucopure EGM is sold by Sandoz in accordance with the description herein above.

Example 5 (comparison) Twelve balls were formed, and tested in accordance with the procedure described in Example 1. In Example 5, the cover had the following composition: Surlyn 1605/8940 46.31 parts by weight Surlyn 1706/9910 46.31 " " " Surlyn 1557/9650 7.38 IV II II Titanium dioxide 1.81 II II " Ultramarine Blue 0.012 " II IV The resulting golf ball was removed from the injection mold cavity, and painted in accordance with the following procedure:: One coat TCL Epoxy Primer 2259-A Et B-1 50 mg./ball wet weight was applied, followed by One coat TCL White Urethane 3225/2061-150 mg./ball wet weight followed by One coat TCL Clear Urethane 2119/1061-70 mg./ball wet weight These TCL paints are sold by Technical Coatings Laboratory of Avon, Connecticut. The balls had a white appearance and had the following average optical properties: Reflectance Number: 76.04 Whiteness Index: 103.53 Yellowness Index: 10.28 Golf bails as manufactured in accordance with this Example have been sold by the applicant by the Spalding Division of Questor Corporation.

Discussion of the Examples Supior golf balls and sample slabs are produced when the procedures of Examples 1, 2, 3, 4 are utilized. It should be noted that in addition to enhancing the Reflectance Number, Whiteness Index, and Yellowness Index, the golf balls produced in accordance with Example 1, 2, 3, and 4 can be formed at a substantial cost saving when compared to the prior art golf balls. That is, the golf balls produced in accordance with Examples 1, 2, 3, and 4 have superior optical properties as compared to the prior art golf balls as per Example 5 and Table I (below). Moreover, the balls produced in accordance with Examples 1, 2, 3, and 4 are significantly cheaper to manufacture in that the expensive white paint system has been eliminated.

Further, because the golf balls of this invention (e.g. as per Examples 1, 2, 3 and 4) are brighter or, in other words, have a whiter appearance, golf balls of the present invention are more saleable when compared to the prior art golf balls. In a white golf ball, it is desirable to have the Reflectance Number as high as possible, the Whiteness Index as high as possible, and the Yellowness Index as low as possible.

Some current preferred ranges of values for Reflectance Number, Whiteness Index, and Yellowness Index are mentioned below.

Reflectance Number: e.g. substantially 80 to substantially 84 (values in excess of substantially 84 may become of especial interest in the future as improved brighteners become available).

Whiteness Index: e.g. substantially 100 to substantially 1 50 (substantially 1 20 to substantially 1 50 may become of especial interest in the future as finishes with improved optical properties are developed; furthermore, values in excess of substantially 1 50 may be of particular interest as improved pigments, brighteners and finishes come on the market). Yellowness Index: e.g.

substantially - 10 to substantially - 25 (yellowness indices less than - 25, for example - 30, may become of especial interest as improved pigments and brighterners become available).

A Table I compares the golf balls of the present inventionfwith a plurality of prior art golf balls. As can be seen, the balls of the present invention have better optical properties when compared to those prior art balls. To the best of the applicant's knowledge, the prior art balls of Table I were painted in accordance with conventional procedures.

Table I Whiteness Yellowness Reflectance Index Index 1) Top-Flite Ball of Example 5 76.04 103.53 -10.28 2) Titleist Pro Trajectory 76.03 83.38 - 2.44 3) Acushnet Pinnacle 78.18 91.59 - 5.11 4) Hogan Apex S 79.42 91.80 - 3.27 5) Wilson Aviator 78.45 Q5.88 - 2.19 6) McGregor MT Tourney 75.50 81.74 - 2.14 7) Dunlop Maxfli 75.72 101.11 - 9.25 Ball of Example 1 83.21 141.18 -20.25 Ball of Example 2 81.32 113.97 -12.78 Ball No. 1 was sold in the past by Spalding Division of Questor Corporation.

Balls Nos. 2 and 3 are sold by the Acushnet Company, New Bedford, MA.

Ball No. 4 is sold by the AMF Ben Hogan Golf Co., Fort Worth, TX.

Ball No. 5 is sold by the Wilson Sporting Goods Co. of River Grove, IL.

Ball No. 6 is sold by the McGregor Golf Co. of Atlanta, GA.

Ball No. 7 is sold by the Dunlop Sports Co. of Greenville, SC.

Claims

1. A golf ball, comprising: (a) polymeric material which is pigmented white, wherein: the surface of said pigmented polymeric material has optical properties affected by an optical brightener, said pigmented polymeric material optionally being comprised by a golf ball cover composition; and (b) a said optical brightener affecting said optical properties.

2. A golf ball as claimed in claim 1, wherein said ball has essentially a uniform cross section.

3. A golf ball as claimed in claim 1 or 2, wherein said ball has a core and a cover.

4. A golf ball as claimed in claim 1 or 2, wherein said ball is a solid golf ball.

5. A golf ball as claimed in any of claims 1 to 3, wherein said surface comprises polymeric material selected from: polyurethane resins; polyolefin resins; and ionic copolymers of olefins having from 2 to 5 carbon atoms and a metal salt of an unsaturated monocarboxylic acid.

6. A golf ball having a core and a cover, wherein said cover comprises: from substantially 99 to substantially 89.5 percent of a natural or synthetic polymer; from substantially 1 to substantially 10 percent of a pigment; and from substantially 0.001 to substantially 0.5 percent of an optical brightener.

7. A golf ball as claimed in claim 6, wherein said cover comprises polymeric material selected from: polyurethane resins; polyolefin resins; and ionic copolymers of olefins having from 2 to 5 carbon atoms and a metal salt of an unsaturated monocarboxylic acid.

8. A golf ball as claimed in claim 6, wherein said cover comprises polymeric material selected from: ionic copolymers of olefins having from 2 to 5 carbon atoms and the sodium salt of an unsaturated monocarboxylic acid having from 2 to 8 carbon atoms; and ionic copolymers of olefins having from 2 to 5 carbon atoms and a zinc salt of an unsaturated moncarboxylic acid having from 2 to 8 carbon atoms.

9. A golf ball as claimed in claim 6, wherein said coyer comprises a mixture of ionic copolymers selected from: ionic copolymers of olefins having from 2 to 5 carbon atoms and the sodium salt of an unsaturated monocarboxylic acid having from 2 to 8 carbon atoms; and ionic copolymers of olefins having from 2 to 5 carbon atoms and a zinc salt of an unsaturated monocarboxylic acid having from 2 to 8 carbon atoms.

10. A golf ball having a core and a cover, wherein said cover comprises: from substantially 99 to substantially 94.8 percent of a natural or synthetic polymer; from substantially 1 to substantially 5 percent of a pigment; and from substantially 0.01 to substantially 0.2 percent of an optical brightener.

11. A golf ball as claimed in claim 10, wherein said cover comprises polymeric material selected from: polyurethane resins; polyolefin resins; and ionic copolymers of olefins having from 2 to 5 carbon atoms and a metal salt of an unsaturated monocaboxylic acid.

12. A golf ball as claimed in claim 10, wherein said cover comprises polymeric material selected from: ionic copolymers of olefins having from 2 to 5 carbon atoms and the sodium salt of an unsaturated monocarboxylic acid having from 2 to 8 carbon atoms; and ionic copolymers of olefins having from 2 to 5 carbon atoms and a zinc salt of an unsaturated monocarboxylic acid having from 2 to 8 carbon atoms.

1 3. A golf ball as claimed in claim 10, wherein said cover comprises a mixture of ionic copolymers selected from: ionic copolymers of olefins having from 2 to 5 carbon atoms and the sodium salt of an unsaturated monocarboxylic acid having from 2 to 8 carbon atoms; and ionic copolymers of olefins having from 2 to 5 carbon atoms and a zinc salt of an unsaturated monocarboxylic acid having from 2 to 8 carbon atoms.

14. A golf ball having a core and a cover, wherein said cover comprises: from substantially 99 to substantially 96.9 percent of a natural or synthetic polymer; from substantially 1 to substantially 3 percent of a pigment; and from substantially 0.01 to substantially 0.1 percent of an optical brightener.

1 5. A golf ball as claimed in claim 14, wherein said cover comprises polymeric material selected from polyurethane resins; polyolefin resins; and ionic copolymers of olefins having from 2 to 6 carbon atoms and a metal salt of an unsaturated monocarboxylic acid.

1 6. A golf ball as claimed in claim 14, wherein said cover comprises polymeric material selected from: ionic copolymerts of olefins having from 2 to 5 carbon atoms and the sodium salt of an unsaturated monocarboxylic acid having from 2 to 8 carbon atoms; and ionic copolymers of olefins having from 2 to 5 carbon atoms and a zinc salt of an unsaturated monocarboxylic acid having from 2 to 8 carbon atoms.

17. A golf ball as claimed in claim 14, wherein said cover comprises a mixture of ionic copolymers selected from: ionic copolymers of olefins having from 2 to 5 carbon atoms and the sodium salt of an unsaturated monocarboxylic acid having from 2 to 8 carbon atoms; and ionic copolymers of olefins having from 2 to 5 carbon atoms and a zinc salt of an unsaturated monocarboxylic acid having from 2 to 8 carbon atoms.

1 8. A golf ball having a core and a cover, wherein said cover comprises substantially 97.9 percent of a natural or synthetic polymer, substantially 2 percent of a pigment, and substantially 0.1 percent of an optical brightener.

1 9. A golf ball as claimed in claim 18, wherein said cover comprises polymeric material selected from: polyurethane resins; polyolefin resins; and ionic copolymers of olefins having from 2 to 5 carbon atoms and a metal salt of an unsaturated monocarboxylic acid.

20. A golf ball as claimed in claim 1 8, wherein said cover comprises polymeric material selected from: ionic copolymers of olefins having from 2 to 5 carbon atoms and the sodium salt of an unsaturated monocarboxylic acid having from 2 to 8 carbon atoms; and ionic copolymers of olefins having from 2 to 5 carbon atoms and a zinc salt of an unsaturated monocarboxylic acid having from 2 to 8 carbon atoms.

21. A golf ball as claimed in claim 18, wherein said cover comprises a mixture of ionic copolymers selected from: ionic copolymers of olefins having from 2 to 5 carbon atoms and the sodium salt of an unsaturated monocarboxylic acid having from 2 to 8 carbon atoms; and ionic copolymers of olefins having from 2 to 5 carbon atoms and a zinc salt of an unsaturated monocarboxylic acid having from 2 to 8 carbon atoms.

22. A golf ball having a core and a cover, wherein said cover comprises (a) from substantially 99 to substantially 89.5 percent of polymeric material selected from: ionic copolymers of olefins having from 2 to 5 carbon atoms and the sodium salt of an unsaturated monocarboxylic acid having from 2 to 8 carbon atoms; and ionic copolymers of olefins having from 2 to 5 carbon atoms and a zinc salt of an unsaturated monocarboxylic acid having from 2 to 8 carbon atoms; (b) from substantially 1 to substantially 10 percent of pigment selected from: titanium dioxide; zinc oxide; and zinc sulfide; and (c) from substantially 0.01 to substantially 0.5 percent of optical brightener which is optionally selected from: Uvitex OB; Phorwhite K-2002; and Leucopure.

23. A golf ball having a core and cover, wherein said cover comprises: (a) from substantially 99 to substantially 89.5 percent of a mixture of ionic copolymers of olefins having from 2 to 5 carbon atoms and the sodium salt of an unsaturated monocarboxylic acid having from 2 to 8 carbon atoms, and ionic copolymers of olefins having from 2 to 5 carbon atoms and a zinc salt of an unsaturated monocarboxylic acid having from 2 to 8 carbon atoms; (b) from substantially 1 to substantially 10 per cent of pigment selected from: titanium dioxide; zinc oxide; and zinc sul.,de; and (c) from substantially 0.01 to substantially 0.5 percent of optical brightener which is optionally selected from: Uvitex OB; Phorwhite K-2002; and Leucopure.

24. A golf ball having a core and a cover, wherein said cover comprises: (a) from substantially 99 to substantially 94.8 percent of polymeric material selected from: ionic copolymers of olefins having from 2 to 5 carbon atoms and the sodium salt of an unsaturated monocarboxylic acid having from 2 to 8 carbon atoms; an ionic copolymers of olefins having from 2 to 5 carbon atoms and a zinc salt of an unsaturated monocarboxylic acid having from 2 to 8 carbon atoms; (b) from substantially 1 to substantially 5 percent of pigment selected from: titanium dioxide; zinc oxide; and zinc sulfide; and (c) from substantially 0.01 to substantially 0.2 percent of optical brightener which is optionally selected from: Uvitex OB; Phorwhite K-2002; and Leucopure.

25. A golf ball having a core and a cover, wherein said cover comprises: (a) from substantially 99 to substantially 94.8 percent of a mixture of ionic copolymers of olefins having from 2 to 5 carbon atoms and the sodium salt of an unsaturated monocarboxylic acid having from 2 to 8 carbon atoms, and ionic copolymers of olefins having from 2 to 5 carbon atoms and a zinc salt of an unsaturated monocarboxylic acid having from 2 to 8 carbon atoms; (b) from substantially 1 to substantially 5 percent of pigment which is selected from: titanium dioxide; zinc oxide; and zinc sulfide; and (c) from substantially 0.01 to substantially 0.2 percent of optical brightener which is optionally selected from: Uvitex OB; Phorwhite K-2002; and Leucopure.

26. A golf ball having a core and a cover, wherein said cover comprises: (a) from substantially 99 to substantially 96.9 percent of polymeric material selected from: ionic copolymers of olefins having from 2 to 5 carbon atoms and the sodium salt of an unsaturated monocarboxylic acid having from 2 to 8 carbon atoms; and ionic copolymers of olefins having from 2 to 5 carbon atoms and a zinc salt of an unsaturated monocarboxylic acid having from 2 to 8 carbon atoms; (b) from substantially 1 to substantially 3 per cent of pigment which is selected from: titanium dioxide; zinc oxide; and zinc sulfide; and (c) from substantially 0.01 to substantially 0.1 percent of optical brightener which is optionally selected from: Uvitex OB; Phorwhite K-2002; and Leucopure.

27. A golf ball having a core and a cover, wherein said cover comprises: (a) from substantially 99 to substantially 96.9 percent of a mixture of ionic copolymers of olefins having from 2 to 5 carbon atoms and the sodium salt of an unsaturated monocarboxylic acid having from 2 to 8 carbon atoms; and ionic copolymers of olefins having from 2 to 5 carbon atoms and a zinc salt of an unsaturated monocarboxylic acid having from 2 to 8 carbon atoms; (b) from substantially 1 to substantially 3 percent of pigment which is selected from: titantium dioxide; zinc oxide; and zinc sulfide; and (c) from substantially 0.01 to substantially 0.1 percent of optical brightener which is optionally selected from: Uvitex OB; Phorwhite K-2002; and Luecopure.

28. A golf ball having a core and a cover, wherein said cover comprises: substantially 97.9 percent of polymeric material selected from: ionic copolymers of olefins having from 2 to 5 carbon atoms and the sodium salt of an unsaturated monocarboxylic acid having from 2 to 8 carbon atoms; and ionic copolymers of olefins having from 2 to 5 carbon atoms and a zinc salt of an unsaturated monocarboxylic acid having from 2 to 8 carbon atoms; (b) substantially 2 percent of pigment which is selected from: titantium dioxide; zinc oxide; and zinc sulfide; and (c) substantially 0.1 percent of optical brightener which is optionally selected from: Uvitex OB; Phorwhite K-2002; and Leucopure.

29. A golf ball having a core and a cover, wherein said cover comprises: (a) substantially 97.9 percent of a mixture of ionic copolymers of olefins having from 2 to 5 carbon atoms and the sodium salt of an unsaturated monocarboxylic acid having from 2 to 8 carbon atoms; and ionic copolymers of olefins having from 2 to 5 carbon atoms and a zinc salt of an unsaturated monocarboxylic acid having from 2 to 8 carbon atoms; (b) substantially 2 percent of a titanium dioxide; and (c) substantially 0.1 percent of Uvitex OB.

30. A golf ball as claimed in any one of claims 1 to 29, wherein Reflectance Number of a said golf ball is in the range substantially 80 to substantially 84.

31. A golf ball as claimed in claim 30, wherein Reflectance Number is substantially 83.21 or substantially 81.32.

32. A golf ball as claimed in any one of claims 1 to 31, wherein Whiteness Index (ASTM E313-73) of a said golf ball is in the range substantially 100 to substantially 150.

33. A golf ball as claimed in claim 32, wherein said Whiteness Index is in the range substantially 100 of substantially 1 20.

34. A golf ball as claimed in claim 32, wherein said Whiteness Index is substantially 141.18 or substantially 113.97.

35. A golf ball as claimed in any one of claims 1 to 34, wherein Yellowness Index (ASTM D1295-70) of a said golf ball is in the range substantially - 10 to substantially - 25.

36. A golf ball as claimed in claim 35, wherein said Yellowness Index is less than substantially - 25.

37. A golf ball as claimed in claim 35, wherein said Yellowness Index is substantially - 20.25 or substantially - 1 2.78.

38. A golf ball, substantially as described in any one of Examples 1 to 4.

39. A golf ball cover composition suitable for use in manufacturing a golf ball according to any one of claims 1 to 38, said composition comprising: polymeric material which is pigmented white; and an optical brightener.

40. A golf ball which incorporates a polymeric material which is pigmented white wherein the surface of said pigmented polymeric material incorporated optical brightener.