AU694793B2 - Coated golf ball - Google Patents

Description

AUSTRALIA

PATENTS ACT 1990 COMPLETE SPECIFICATION NAME OF APPLICANT(S): Sumitomo Rubber Industries, Ltd.

ADDRESS FOR SERVICE: DAVIES COLLISON CAVE Patent Attorneys I Little Collins Street, Melbourne, 3000.

INVENTION TITLE: Coated golf ball ft ft.

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4 ft la COATED GOLF BALL DEFINITION OF TERMS The term "coated golf ball" means a golf ball body which is coated with paint. Accordingly, an article which is generally called "golf ball" by consumers and commercially available belongs to the "coated golf ball". In the present specification, the term "golf ball" may sometimes indicate the "coated golf ball" according to the common usage.

The term "golf ball body" means a golf ball before coating with paint.

FIELD OF THE INVENTION The present invention relates to a coated golf ball comprising a golf ball body and a paint layer formed thereon. More particularly, it relates to a coated golf ball having good appearance by improving the leveling properties of the paint.

BACKGROUND OF THE INVENTION Golf balls are generally coated with paint in order to look Si beautiful or to prevent damage to the ball surface. The paint layer is composed of an enamel paint containing pigments such as titanium oxide, etc., and a clear paint containing no pigments, formed on the enamel paint, got 20 or a clear paint only.

Hitherto, the paint has primarily been coated by an air gun and is applied in such a manner that the coated film has 20-30 gm I l ln111)1 n- «T ifinin-'111 nni 1 P:\OPER\AXS'30549-95.CLM- 18/6/98 -2thickness. The golf ball has concave recesses, called "dimples", on all over the surface, to improve flying performance. However, if a paint is applied to form a coated film having over 20 gim thickness with one coat, the dimple profile is deformed and the flying performance are degraded.

Accordingly, the film thickness that can be applied without damaging the dimple profile ha is considered to be about 10 gm, but this coating amount may reduces the leveling property of the paint, adversely impairing the golf ball appearance. Therefore, at a slight sacrifice to the flying performance, golf balls are coated with paint to form a film thickness of about 20 ilm per one coat.

Recently, electrostatic coating is used for coating golf balls and paint is applied at about 20 lm per one coat without damaging the Sdimple profile. However, since atomized paint particles are extremely smaller than those of air gun coating, solvents evaporate during coating and the leveling property of the paint would degrade.

The present invention advantageously provides a coated golf ball E which achieves satisfactory paint levelling property, keeps excellent flying performance, and provides excellent appearance, even when a paint is applied at such a coating amount that would not damage the dimple profile after coating.

1 SUMMARY OF THE INVENTION According to the present invention there is provided a coated golf ball comprising a golf ball body and a paint layer formed thereon, wherein said paint layer is formed from a paint containing a fluorine-containing surfactant in an mount of from 0.1 to 10% by weight based on the solid content of the paint, said

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i i. i. *I~Lur, i- i~i P\OPER\AXD\30549-95.CLM 1816(98 -3fluorine-containing surfactant being selected from the group consisting of a perfluoroalkyl carboxylic acid having 4-20 carbon atoms or its salts, a perfluoroalkyl sulfonic acid having 4-20 carbon atoms or its salts, and a perfluoroalkyl phosphoric ester having 4-20 carbon atoms.

BRIEF DESCRIPTION OF THE DRAWINGS

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4. 4 FIG. 1 is a diagrammatic view in cross section of a dimple on the golf ball surface.

DETAILED DESCRIPTION OF THE INVENTION The paint for the golf ball used for the present invention is characterized by containing a fluorine-containing surfactant. The fluorinecontaining surfactant is art-known, and can be defined as a surfactant of which a part or all of hydrogens bonded to carbons of the hydrophobic group are substituted with F (fluorine). According to the invention, the surfactant is a fluorinecontaining surfactant having 4 to 20 carbon atoms in each molecule. If the number of carbon atoms is less than 4, the desired levelling property is unable to be obtained, while if it exceeds 20, the surfactant is difficult to dissolve in a solvent. In order to achieve a satisfactory levelling property, the surfactant is added within the range of 0.1-10% by weight, preferably 0.5-3% by weight, based on the solid content of the paint.

The paint used for the present invention can contain epoxy L c resin, acryl resin or urethane resin as film-forming resin, but the urethanebased paint is most preferable. It is desirable to choose paint, taking adhesion to the golf ball body into account. More concretely, the paint used in the present invention comprises as main resin, an active hydrogen-containing compound, such as polyester-polyol or polyetherpolyol and as curing agent, an isocyanate compound. The two components and may either be divided into two packages which are mixed upon applying, or be one package after controlling the reactivity of the two components. The isocyanate compound may include 1,6hexamethylene diisocyanate modified material (biuret material, trimethylolpropane modification, trimerization, etc.) and tolylene diisocyanate modified material.

If the paint is an enamel paint, a coloring agent, particularly white pigment (for example, titanium oxide) is contained. The coloring agent or pigment may be present in an amount of 40-60 by weight, preferably 50 to 55 by weight, based on a solid content of the paint.

When the amount of the white pigment is smaller than 40 by weight, hiding power is inferior. When it exceeds 60% by weight, the physical properties of the coated film is inferior. In the case of a clear paint, a 20 coloring agent is basically not contained.

The paint may further contain various additives or diluents, etc. in addition to the above-mentioned components. Examples of additives include a ultraviolet inhibitor, photostabilizer, filler pigment, and fluorescence material or fluorescence brightener An amount of the additives is 0.1-10% by weight based on the solid content of the paint.

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i L The fluorescence material or fluorescence brightener to be formulated in the paint can be those commonly known and used in golf balls. Specific examples are 2,5-bis[5'-t-butylbenzoxyazoryl(2)]thiophene (commercially available from Japan Ciba-Geigy Co. as YUBITEX OB), 7- (2h-naphthol(1,2-d)-triazole-2-Y1)-3-phenyl-cusline (commercially available from Sadoz Company as Leucopure EGM), etc., which are preferable, and a biazoline derivative (commercially available from Mobey Chemical Corporation as Phorwhite K-2002), oxazole-based agents (commercially available from Sumitomo Chemical Industries Co. as Whitefuller HCS, PCS, and B, and Hostalux KCB from Hechist Japan An amount of these agents may be 0.005-1.0% by weight based on the solid content of the paint.

The diluents formulated in the paint include ketones such as acetone, methyl ethyl ketone; aromatic hydrocarbons such as toluene, xylene; esters such as ethyl acetate; and the like. An amount of the diluent is not specifically limited but is preferably 30-80% by weight based on the weight of the paint.

The golf ball body may be a one-piece ball obtained by vulcanizing and molding a rubber composition mainly containing cis-1, 4- 20 polybutadiene rubber. It also may be a two-piece ball which is obtained by vulcanizing a rubber composition mainly containing cis-1,4-polybutadiene rubber to form a solid core, which is then covered with an ionomer cover.

In addition, the golf ball body may be a thread-wound ball comprising a thread wound core and a cover layer mainly composed of transpolyisoprene, formed on the thread wound core. The thread wound core is ft ft.

ft I t Vi *1 4 t aI *4 'ft M 0 1111111111 6 composed of a liquid or solid center and a thread rubber layer wound on the center.

A coating method for the paint is not specifically limited, but preferably includes air gun coating or electrostatic coating, and the like.

The paint used in the present invention may preferably has a surface tension of 20-26.5 dyne/cm where wetting to the golf ball surface is satisfactory and uniform coating is achieved. If it exceeds 26.5 dyne/cm, wetting to the ball surface is deteriorated, while if it is less than 20, the effect is not changed.

The coating process can explain as follow. That is, a golf ball body is coated with the enamel paint to form an enamel paint layer on which transfer-marking of tradename, etc. is conducted using a transfer foil, etc. comprising the resin chosen from a group consisting of polyamide resin, acrylic resin, and urethane resin, as well as nitrocellulose as major resin, and then, is coated with a clear paint for finish. This process is publicly known with respect to the golf ball manufacturing. It is also possible to use a method in which the enamel paint is not coated but the clear paint only is applied. In the present invention, it is preferable to use enamel paint and clear paint, both of which provide features of the present i 20 invention.

According to the present invention, even when a golf ball is coated at such a coating amount that would not damage the dimple profile after coating, the leveling property of the paint is satisfactory, offering a coated golf ball having excellent flying performance and excellent coating appearance.

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EXAMPLES

The present invention will be described further in detail with reference to the following examples; however, these examples are not construed to limit the scope of the invention.

Examples 1 to 13 and Comparative Examples 1 to 6 Using the following paints, two-piece golf balls having 432 dimples on its surface comprising a solid core and a ionomer cover covering the solid core were coated, The coating method, coating weight, and coating process are explained hereinafter.

(Paints) Clear paint Two-package type clear paint (matrix: polyester polyol; curing agent: hexamethylene diisocyanate modified material; solid content about O t 26%; specific gravity: 0.92).

Enamel paint The enamel paint similar to the clear paint above except that titanium oxide is contained 50% by weight based on the solid content t ,(matrix: polyester polyol; curing agent: hexamethylene diisocyanate S: modified material; solid content: about 45%; specific gravity: 1.12).

20 To both of the above paints, a fluorine-containing surfactant S, chosen from A to E below was formulated in a specified amount. Table 1 shows the type and the formulating amount.

(fluorine-containing surfactant) L 8 A: MEGAFAK F173 (an oligomer having a perfluoroalkyl group and a lipophilic group) B: MEGAFAK F177 (an oligomer having a perfluoroalkyl group, a lipophilic group and a hydrophilic group) C: FLUORARD FC-431 (fluorinated alkylester) D: FLUORARD FC-431 (fluorinated alkylester) E: MEGAFAK F191 (perfluorophosphate) B, and E are commercially available from Dai Nippon Ink and Chemicals Co., Ltd. and C and D from 3M Company) (Electroconducting agent) Only when electrostatic coating was used, a solution in which plastic electric conducting agent NC (available from Cashew Company) was diluted to the concentration of 1% by weight with isopropyl alcohol was coated to a golf ball in advance and dried until isopropyl alcohol evaporated to impart electric conductivity prior to paint application.

(Coating Method) S a. Air-gun coating: The paint was coated while the air gun was moved At 5 m/sec in the distance between 10 cm above and 10 cm below the golf ball. In such event, the golf ball was rotated at 200 rpm.

20 b. Electrostatic coating: 120,000-V electric charge was given to a disc rotating at 30,000 rpm and the disc was tilted at 70 to horizontal.

The golf ball revolves around the disc (R 0.5 m) at 60 rpm while rotating around its axis.

(Coating Weight) The coating weight adhering to the golf ball was given by the 9 following formula after the paint was dried at 500C for one day.

(Coating weight) (Tj T 2 where, T, is the coated film thickness (gim) at the land portion 1 of the golf ball, and T 2 is the coating film thickness at the bottom portion 3 of the golf ball. The land portion 1 and bottom portion 3 are shown in Fig. 1, and the portion 2 is called "edge portion".

4 4 0 a4 Table 1 Paint Paint additives

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Coating method IType ICoating weight (itm) ITypeI Concentration (wt5'o)

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Examples 2 1j 25 A1 1.0 b 3 1 25 A[ 3.0 b 4 1 25 A 8.0 b 1 25 B 1.0 b 6 I 25 C 1.0 b 7 1 25 A 1.0 b 8 1 13 A i.0 1 a g 1 25 1D 1.0 b 25 E .1.0 b 1125 A0.05 b 1jiL 25 B~ 0.05 [b 13 1I 25 I C 10.05 b 4444 4I 4$ *4 4.44 @445 44 4 4 4 I 4 44$444 4 44..

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9 44 .4 #4 44 5 44 1 4491 *9 9 14 1 4: I I Comparative Examples 2 II 40 b 3 1[ 13 4 ji[ 25 a 5 I 25 A 15.0 a i Table 2 Appearance Flying performance Surface tension Example No.I Dimpl _profilej Total Lse Dipecarry Trajectory elevation angle dyne/cm (2300) L 0o 0 250.3 13.5 f25.9 2 0 0 25.13522 3]o 0 0 249.6[ 13.6[ 24.6 4 0 0 249.7 13.7 24.1 0 0 250.1 13.4 25.3 6~ 0 0~ 250.0 13.6 f25.3 Examples 7 0 0 250.6 13.4 25.2 8 ]0 0 249.3 [13.7 25.2 9 0 0 250.6 13.6 25.1 0 0 250.2 13.6 25.3 11 AL 0 f249.9 13.4 26.0 12 AL 0 250.2 13.5 26.1 13 A 0 250.0 13.5 26.0 0 xf 250.51 13.5 26.9 2 0 X241.1 14.7 26.9 Compara- 31 X 1 0 1249.7 13.7 j 26.9 tive examples 4 0 f 240.7 f14.9 J 26.9 0 A 245.2 j14.2 23.9 6- 2 5 0 9 j 13.3j_ *0*4

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(Evaluation Method) 1. Visually checked appearance Luster 0: Good A: Lustrous but the surface slightly feels' rough.

x: No luster Dimple shape 0: Dimple profile is clear.

A: Dimple edge is slightly dim.

I x: The whole dimple is dim.

2. Flying performance: By a swing machine available from True I Temper Company using a driver, golf balls were hit at a club head speed of m/sec and the total carry and trajectory elevation angle were measured.

Throughout this specification and the claims which follow, unless the Scontext requires otherwise, the word "comprise", and variations such as "comprises" and "comprising", will be understood to imply the inclusion of a stated integer or group of integers or steps but not the exclusion of any other ,tt: integer or group of integers or steps.

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Claims (5)

1. A coated golf ball comprising a golf ball body and a paint layer formed thereon, wherein said paint layer is formed from a paint containing a fluorine-containing surfactant in an amount of from 0.1 to 10% by weight based on the solid content of the paint, said fluorine-containing surfactant being selected from the group consisting of a perfluoroalkyl carboxylic acid having 4-20 carbon atoms or its salts, a perfluoroalkyl sulfonic acid having 4-20 carbon atoms or its salts, and a perfluoroalkyl phosphoric ester having 4-20 carbon atoms.

2. The coated golf ball according to claim 1 wherein said paint comprises epoxy resin, acryl resin or urethane resin as film-forming resin. 9 9

3. The coated golf ball according to claim 1 wherein said paint comprises as a main resin, an active hydrogen-containing compound, such as ea, polyester-polyol or polyether-polyol and as a curing agent, an isocyanate compound.

4. The coated golf ball according to claim 1 wherein said paint comprises a pigment. The coated golf ball according to claim 1 wherein said golf ball body is a two-piece ball which is obtained by vulcanizing a rubber composition mainly containing cis-1, 4-polybutadiene rubber to form a solid core, which is then covered with an ionomer cover. T 0 f I r P:\OPER\AXD\30549-95,CLM 18/6/98

14- 6. The coated golf ball according to claim I wherein said paint has a surface tension of 20 to 26.5 dyne/cm. 7. A golf ball substantially as hereinbefore described with reference to the drawings and/or Examples, but excluding the Comparative Examples. DATED this 18th day of June, 1998 Sumitomo Rubber Industries, Ltd. by DAVIES COLLISON CAVE Patent Attorneys for the Applicants t4* 4* It 14 #441 44 4 4 4 4 444 1 .4,4 4 4 '.44 .4 44 4 4 4 1 *4 -c 4 4 4 41 4,44 *t *1 4 44 44 ~4 4 It 4 4 44 4 4 41 414414 A golf ball substantially as hereinbefore described with reference to the drawings and/or Examples. 11. The steps, features, compositions and compounds disclosed herein or referred to or indicated in the specification and/or claims of this application, individually or collectively, and any and all combinations of any two or more of said steps or features. DATED this TWENTY SIXTH day of SEPTEMBER 1995 Sumitomo Rubber Industries, Ltd. a a *a a Iete a s a a e a a a,* *eo a a a Itt 1 a (I i) 9 by DAVIES COLLISON CAVE Patent Attorneys for the applicant(s) 1 1- I- I-1- ABSTRACT OF THE DISCLOSURE The present invention provides a coated golf ball which achieves satisfactory paint leveling property, keeps excellent flying performance, and provides excellent appearance, even when a paint is applied at such a coating amount that would not damage the dimple profile after coating. The coated golf ball of the present invention comprises a golf ball body and a paint layer formed thereon, wherein the paint layer is formed from a paint containing a fluorine-containing surfactant. i i 1--