JP2008253642A - Golf ball - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a golf ball, having excellent visibility and excellent discrimination performance from a white ball. <P>SOLUTION: The golf ball 2 includes a body 4, a mark layer 6 and a paint layer 8. The surface of the golf ball 2 is discriminated between a mark part 18 and a non-mark part 20. The golf ball has the following expressions (I) to (III). (I) 50≤L1≤80, (II)L1<L2, and (III) (al<SP>2</SP>+b1<SP>2</SP>)<SP>1/2</SP>>(a2<SP>2</SP>+b2<SP>2</SP>)<SP>1/2</SP>, wherein L1 designates L* of the non-mark part; L2 designates L* of the mark part 18; a1 designates a* of the non-mark part 20; a2 designates a* of the mark part 18; b1 designates b* of the non-mark part 20; and b2 designates b* of the mark part 18. L*, a* and b* are indexes in CIELAB display system. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a golf ball having a mark portion.

  The golf ball includes a core and a cover. A general golf ball is colored almost white. Coloring is achieved by dispersing a pigment in the cover. Coloring may be achieved by painting the surface of the cover. There are also golf balls colored in colors other than white, such as blue and pink.

  The golf ball is marked. The brand and ball number are displayed by marking. Golfers can distinguish their balls from others by brand. Golfers can also identify their own balls from others by the ball number.

Various proposals regarding the color of golf balls have been made. JP-A-10-155937 discloses a golf ball having L of 80 or more, a of -30 to 30, and b of -30 to 30. JP-A-2004-33594 discloses a golf ball having (L- (a ² + b ² ) ^1/2 ) of 35 or more and 55 or less. Japanese Patent Application Laid-Open No. 2006-187601 discloses a golf ball in which L is 45 or less and (a ² + b ² ) ^1/2 is 5 or less. Japanese Utility Model Registration No. 3038312 discloses a golf ball having a darker mark than the main body.
Japanese Patent Laid-Open No. 10-155937 JP 2004-33594 A JP 2006-187601 A Utility Model Registration No. 3038312

  The color of the golf ball disclosed in JP-A-10-155937 is a so-called pastel color. The color of this golf ball is close to white. In golf, a golf ball that is stationary after flight is often viewed from a distance. It is difficult to distinguish the golf ball from an ordinary white golf ball from a distance.

In the golf ball disclosed in JP-A-2004-33594, L is small or (a ² + b ² ) is large. When the golf ball flies, the golfer tends to lose sight of the golf ball. This golf ball has poor visibility during flight. The visibility when the background is a tree is particularly bad. Furthermore, this golf ball is inferior in visibility from a distance when it is on the lawn.

  The color of the golf ball disclosed in JP-A-2006-187601 is dark. This golf ball has poor visibility during flight. The visibility when the background is a tree is particularly bad. Furthermore, this golf ball is inferior in visibility from a distance when it is on the lawn.

  In the golf ball disclosed in Utility Model Registration No. 3038312, the color of the non-marked portion is close to white. It is difficult to distinguish the golf ball from an ordinary white golf ball from a distance. Further, the mark portion of this golf ball does not contribute sufficiently to the visibility.

  An object of the present invention is to provide a golf ball having excellent visibility and excellent discrimination from a white ball.

The golf ball according to the present invention includes a mark portion and a non-mark portion on the surface thereof. This golf ball has the following formulas (I) to (III).
50 ≦ L1 ≦ 80 (I)
L1 <L2 (II)
(A1 ² + b1 ² ) ^1/2 > (a2 ² + b2 ² ) ^1/2 (III)
In these formulas, L1 represents a non-mark portion ^{L *,} L2 represents the ^{L *} of the mark portion, a1 represents the ^{a *} unmarked portion, a2 represents the ^{a *} mark portion, b1 is unmarked It represents a part of ^{b *,} and, b2 represents the ^{b *} of the mark portion. L ^* , a ^* and b ^* are indices in the CIELAB display system.

Preferably, L2 exceeds 65, and the difference between L2 and L1 (L2−L1) is 15 or more and 30 or less. Preferably, the difference between (a2 ² + b2 ² ) ^1/2 and (a2 ² + b2 ² ) ^1/2 is 5 or more. Preferably, (a2 ² + b2 ² ) ^1/2 is 15 or less.

  In this golf ball, the color of the non-marked portion is significantly different from white. Therefore, this golf ball is excellent in distinguishability from the white ball. In this golf ball, the mark portion contributes to visibility. Since L1 is 50 or more, the non-marked portion does not significantly impair visibility. In this golf ball, both discrimination and visibility are compatible. By using this golf ball, wrong balls and lost balls are suppressed.

  Hereinafter, the present invention will be described in detail based on preferred embodiments with appropriate reference to the drawings.

  FIG. 1 is a cross-sectional view showing a part of a golf ball 2 according to an embodiment of the present invention. The golf ball 2 includes a main body 4, a mark layer 6, and a paint layer 8. The main body 4 includes a spherical core 10 and a cover 12 located outside the core 10. The main body 4 may be composed of a single layer. The golf ball 2 includes dimples 14 and lands 16 on the surface thereof. The golf ball 2 may include another paint layer between the cover 12 and the mark layer 6.

  The core 10 is formed by crosslinking a rubber composition. Examples of the base rubber of the rubber composition include polybutadiene, polyisoprene, styrene-butadiene copolymer, ethylene-propylene-diene copolymer, and natural rubber. Preferably, a co-crosslinking agent is used for crosslinking. Preferably, the rubber composition includes an organic peroxide. The core 10 may be composed of two or more layers.

  The cover 12 is made of a resin composition. A thermoplastic resin or a thermosetting resin can be used for the cover 12. Typical resins are ionomer resins and polyurethanes. The cover 12 may include a styrene elastomer, a polyamide elastomer, a polyester elastomer, and a polyolefin elastomer. The cover 12 may be composed of two or more layers.

  The cover 12 includes a pigment. The cover 12 is colored with the pigment. Blue pigments, purple pigments, green pigments, yellow pigments, orange pigments, red pigments and the like can be used. Examples of blue pigments include bitumen, cobalt blue, alkali blue lake, Victoria blue lake, phthalocyanine blue, metal-free phthalocyanine blue, phthalocyanine blue partially chlorinated, fast sky blue, and indanthrene blue BC. Examples of purple pigments include manganese purple, fast violet B, and methyl violet lake. Examples of the green pigment include chrome green, chromium oxide, pigment green B, malachite green lake, and fanal yellow green G. Yellow pigments include yellow lead, zinc yellow, cadmium yellow, yellow iron oxide, mineral fast yellow, nickel titanium yellow, navel yellow, naphthol yellow S, Hansa yellow G, Hansa yellow 10G, benzidine yellow G, benzidine yellow GR, Examples include quinoline yellow lake, permanent yellow NCG and tartrazine lake. Examples of the orange pigment include red mouth yellow lead, molybdenum orange, permanent orange GTR, pyrazolone orange, vulcan orange, indanthrene brilliant orange RK, benzidine orange G and indanthrene brilliant orange GK. Examples of red pigments include bengara, cadmium red, red lead, mercury cadmium sulfide, permanent red 4R, risor red, pyrazolone red, watching red calcium salt, lake red D, brilliant carmine 6B, eosin lake, rhodamine lake B, and alizarin lake. And brilliant carmine 3B.

  A white colorant is also added to the cover 12. A typical white colorant is titanium dioxide. A cover 12 having a desired color can be obtained by using titanium dioxide in combination with another pigment. The amount of titanium dioxide is preferably 0.1 parts by mass or more and 5 parts by mass or less with respect to 100 parts by mass of the base resin. The amount of the other pigment is preferably 0.001 part by mass or more and 5 parts by mass or less with respect to 100 parts by mass of the base resin.

  An appropriate amount of a filler such as barium sulfate, an antioxidant, an ultraviolet absorber, a light stabilizer, a fluorescent agent, and a fluorescent brightening agent is blended in the cover 12 as necessary.

  The mark layer 6 is made of an ink composition. This ink composition includes a base resin and a pigment. Specific examples of the base resin include epoxy resins, polyester polyols, polyether polyols, polyurethane polyols, and nitrocellulose.

  Preferably, a two-component curable ink composition is used for the mark layer 6. A typical curing agent for this ink composition is an isocyanate. Aliphatic diisocyanates, alicyclic diisocyanates, aromatic diisocyanates and araliphatic diisocyanates can be used. Specific examples of the isocyanate include isophorone diisocyanate, hexamethylene diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, tetramethylxylylene diisocyanate, hydrogenated diphenylmethane diisocyanate and tolylene diisocyanate. As for the compounding quantity of isocyanate, 5 to 30 mass parts is preferable with respect to 100 mass parts of base resin.

  The color of the mark layer 6 is different from the color of the cover 12. The mark layer 6 displays the manufacturer name, brand 16, ball number, and the like. As will be described later, the brightness of the mark layer 6 is high. The kind and amount of the pigment in the ink composition are adjusted so that a desired brightness is obtained. By mainly using a white pigment, the mark layer 6 with high brightness can be obtained. Examples of white pigments include zinc white, titanium oxide, antimony white, zinc sulfide, barite powder, barium carbonate, clay, silica, talc, and alumina white. A small amount of a blue pigment, a purple pigment, a green pigment, a yellow pigment, an orange pigment, a red pigment, and the like may be used together with the white pigment.

  The mark layer 6 is formed by printing on the surface of the cover 12. Pad printing, engraving printing, ink jet printing, transfer film printing, and the like can be employed. From the viewpoint of productivity, pad printing is preferable. In pad printing, an ink composition is prepared by mixing a main agent (including a base resin, a pigment, and the like), a curing agent, and a solvent. With this ink composition, an image is formed on the plate. By pressing the pad against this plate, the image is transferred to the pad. When the pad is pressed against the main body 4 of the golf ball 2, the image is transferred to the main body 4. After the transfer, the ink composition is dried and cured to complete the mark layer 6. Although the golf ball 2 includes the dimples 14, since the pads are flexible and have excellent deformability, printing inside the dimples 14 is also possible.

  The type and amount of the solvent are adjusted so that the desired viscosity of the ink composition is obtained. Specific examples of the solvent include ethyl acetate, propylene glycol monomethyl ether acetate, butanol, cellosolve, 3-methoxy-3-methylbutyl acetate, n-butyl acetate, cyclohexane, methyl ethyl ketone, benzene, toluene and xylene. The ratio of the solvent in the ink composition is 2% by mass or more and 50% by mass or less.

  The thickness of the mark layer 6 is preferably 1 μm or more and 50 μm or less. The mark layer 6 having a thickness of 1 μm or more is excellent in concealment. Due to the excellent concealing property, the golf ball 2 in which the difference between the color of the mark layer 6 and the color of the cover 12 is clear is obtained. In this respect, the thickness of the mark layer 6 is more preferably 3 μm or more, and particularly preferably 5 μm or more. The mark layer 6 having a thickness of 50 μm or less is excellent in productivity. In this respect, the thickness is more preferably equal to or less than 30 μm, and particularly preferably equal to or less than 20 μm.

  The paint layer 8 is colorless and transparent. Through the paint layer 8, the cover 12 and the mark layer 6 can be observed. The paint layer 8 may contain some pigment. The paint layer 8 covers the cover 12 or the mark layer 6. The mark layer 6 is protected by the paint layer 8. The thickness of the paint layer 8 is 3 μm or more and 100 μm or less. The paint layer 8 may be provided only directly above the mark layer 6. The golf ball 2 may include two or more paint layers 8. The paint layer 8 may not be provided.

  The paint layer 8 is formed by applying a paint. Electrostatic coating, spray gun coating, brush coating, etc. can be employed. Examples of the base resin for the paint include polyurethane, epoxy resin, polyester, acrylic resin, and the like. From the viewpoint of the durability of the paint layer 8, a two-component curable paint is preferable. Typically, a two-component curable polyurethane paint is used for the paint layer 8. If necessary, additives such as antioxidants, ultraviolet absorbers, light stabilizers, fluorescent agents, and fluorescent brighteners are blended in appropriate amounts in the paint.

  As shown in FIG. 1, the surface of the golf ball 2 is divided into a mark portion 18 and a non-mark portion 20. The mark portion 18 is a portion immediately above the mark layer 6 in the surface of the golf ball 2 (the surface of the paint layer 8 in the present embodiment). The non-mark part 20 is a part other than the mark part 18 on the surface of the golf ball 2. The ratio of the area of the mark portion 18 to the surface area of the golf ball 2 is 0.5% or more and 20% or less. Most of the surface of the golf ball 2 is the non-mark portion 20.

In the present invention, the colors of the mark portion 18 and the non-mark portion 20 are displayed by the indices L ^* , a ^* and b ^* in the CIELAB display system. The indices L ^* , a ^* and b ^* are calculated by the following mathematical formulas.
L ^* = 116 (Y / Yn) ¹ / 3-16
a ^* = 500 ((X / Xn) ¹ /3-(Y / Yn) ^1/3 )
b ^* = 200 ((Y / Yn) ¹ /3-(Z / Zn) ^1/3 )
In these mathematical formulas, X, Y, and Z are tristimulus values in the XYZ display system, and Xn, Yn, and Zn are tristimulus values on the perfect diffuse reflection surface. The CIELAB display system is a standard determined in 1976 by the International Commission on Illumination (CIE). In Japan, the CIELAB display system is adopted in “JIS Z 8729”.

L ^* is a lightness index. a ^* and b ^* are indices that correlate with hue and saturation. The negative direction of a ^* is the green direction, and the positive direction is the red direction. The negative direction of b ^* is the blue direction, and the positive direction is the yellow direction.

In the present invention, the index L ^* , a ^*, and b ^* of the marked portion 18 and the non-marked portion 20 are measured by a spectrocolorimeter “CM-3500d” manufactured by Konica Minolta. The light receiving portion is applied to the surface of the golf ball 2 (in this embodiment, the surface of the paint layer 8), and measurement is performed. “Standard light D ₆₅ ” is adopted as the light source. The color temperature of this light source is 6504k. As the spectral sensitivity, “2 ° field of view” is adopted.

Herein, L1 represents a non-mark portion 20 ^{L *,} L2 represents the ^{L *} of the mark portion 18, a1 represents the non-mark portion 20 ^{a *,} a2 represents the ^{a *} mark 18 , b1 represents an unmarked portion 20 ^{b *,} and, b2 represents the ^{b *} of the mark portion 18.

This golf ball 2 has the following mathematical formula (I).
50 ≦ L1 ≦ 80 (I)
The golf ball 2 has a lightness index L1 of the non-marked portion 20 of 80 or less. In a general white ball, L1 of the non-mark part 20 is 90 or more. The overall brightness of the golf ball 2 is clearly smaller than that of a normal white ball. After the shot, the golfer moves forward by walking or by cart. The golfer sees his golf ball 2 and another person's ball from a distance. Because the brightness is different, the golfer can distinguish his golf ball 2 from the ball of another person. This golf ball 2 is excellent in distinguishability. From the viewpoint of discrimination, L1 is more preferably 76 or less, and particularly preferably 71 or less.

  In this golf ball 2, L1 is 50 or more. In other words, the color of the non-mark part 20 is not too dark. During the flight of the golf ball 2, even if there is a tree in the background, it is difficult for the golfer to lose sight of the golf ball 2. When the golfer sees the golf ball 2 on the lawn from a distance, the lawn and the golf ball 2 can be distinguished. This golf ball 2 is excellent in visibility. From the viewpoint of visibility, L1 is more preferably 66 or more.

This golf ball 2 has the following mathematical formula (II).
L1 <L2 (II)
In other words, the brightness of the mark portion 18 is greater than the brightness of the non-mark portion 20. This mark portion 18 is conspicuous. Excellent visibility can be achieved by the mark portion 18 having high brightness. From the viewpoint of visibility, L2 is preferably more than 65, more preferably 75 or more, and particularly preferably 90 or more.

  The difference (L2−L1) is preferably 15 or more. In the golf ball 2 in which the difference (L2−L1) is 15 or more, the discrimination by the non-mark part 20 and the visibility by the mark part 18 are compatible. In this respect, the difference (L2−L1) is more preferably 19 or more. The difference (L2−L1) is preferably 30 or less. In the golf ball 2 in which the difference (L2−L1) is 30 or less, the non-marked portion 20 does not hinder the visibility. In this respect, the difference (L2−L1) is more preferably 24 or less.

This golf ball 2 has the following mathematical formula (III).
(A1 ² + b1 ² ) ^1/2 > (a2 ² + b2 ² ) ^1/2 (III)
(A1 ² + b1 ² ) ^1/2 represents the saturation of the non-mark part 20. (A2 ² + b2 ² ) ^1/2 represents the saturation of the mark portion 18. In the golf ball 2 having the mathematical formula (III), the saturation of the non-mark portion 20 is greater than the saturation of the mark portion 18. In the golf ball 2, excellent distinguishability is achieved by the non-mark portion 20, and excellent visibility is achieved by the mark portion 18. Further, the combination of the non-mark part 20 and the mark part 18 achieves an excellent design.

From the viewpoint of discriminability, visibility and design, the difference between (a1 ² + b1 ² ) ^1/2 and (a2 ² + b2 ² ) ^1/2 is preferably 5 or more, more preferably 16 or more, and particularly preferably 18 or more. preferable. The difference is preferably 28 or less, particularly preferably 24 or less.

From the viewpoint of discrimination by the non-marked portion 20, (a1 ² + b1 ² ) ^1/2 is preferably 20 or more, more preferably 23 or more. From the viewpoint of visibility by the non-marked portion 20, (a1 ² + b1 ² ) ^1/2 is preferably 33 or less, particularly preferably 29 or less.

From the viewpoint of design and visibility by the mark portion 18, (a2 ² + b2 ² ) ^1/2 is preferably 15 or less, more preferably 10 or less, and particularly preferably 5 or less. (A2 ² + b2 ² ) ^1/2 may be zero.

  The golf ball 2 may include other mark layers. The color of the other mark layer may be the same as or different from the color of the mark layer 6 described above.

  Hereinafter, the effects of the present invention will be clarified by examples. However, the present invention should not be construed in a limited manner based on the description of the examples.

[Example 1]
100 parts by weight of polybutadiene (trade name “BR-730” from JSR), 25 parts by weight of zinc acrylate, 10 parts by weight of zinc oxide, 15 parts by weight of barium sulfate, 0.5 parts by weight of diphenyl disulfide and 0.8 parts by mass of dicumyl peroxide was kneaded to obtain a rubber composition. This rubber composition was put into a mold composed of an upper mold and a lower mold each having a hemispherical cavity and heated at 170 ° C. for 20 minutes to obtain a core having a diameter of 38.9 mm.

  45 parts by weight of sodium-neutralized ionomer resin (DuPont's trade name “Surlin 8945”), 45 parts by weight of zinc-neutralized ionomer resin (DuPont's trade name “Surlin 9945”), 10 parts by weight of styrene block Containing thermoplastic elastomer (trade name “Lavalon SR04” from Mitsubishi Chemical Corporation), 3 parts by mass of titanium dioxide and 0.02 parts by mass of blue pigment (trade name “PE-D 06G177 Blue” from Dainichi Seika Kogyo Co., Ltd.) Were kneaded with a twin-screw kneading extruder to obtain a resin composition. The core was put into a final mold having a large number of pimples on the inner peripheral surface, and the resin composition was injected around the core by an injection molding method to form a cover having a thickness of 1.9 mm. A large number of dimples having a reversed pimple shape were formed on the cover. The color of the cover was blue close to white. The surface of this cover was polished.

  100 parts by mass of a main agent (trade name “EPH 46 indigo” from Navitas), 10 parts by mass of a curing agent (hexamethylene diisocyanate) and 20 parts by mass of a solvent (ethyl acetate) were obtained to obtain an ink composition. A mark layer was formed on the surface of the cover by pad printing using the ink composition, and the color of the mark layer was almost white.

  A clear paint based on a two-component curable polyurethane was prepared. The main component of this paint is a mixture of polyether polyol and polyester polyol. The hydroxyl value of this main agent is 82 mgKOH / g. The curing agent for this paint is hexamethylene diisocyanate. The NCO: OH equivalent ratio of this paint is 1.3: 1.0. This paint was applied to the cover and the mark layer with a spray gun. This paint was dried at a temperature of 40 ° C. for 120 minutes to obtain a paint layer having a thickness of about 10 μm. Thus, a golf ball of Example 1 having a diameter of 42.7 mm and a mass of about 45.4 g was obtained.

[Examples 2 to 3 and Comparative Examples 1 to 2]
Golf balls of Examples 2 to 3 and Comparative Examples 1 to 2 were obtained in the same manner as in Example 1 except that the amount of the blue pigment in the cover was changed as shown in Table 1 below.

[Example 4 and Comparative Examples 3 to 4]
Example 1 except that instead of the blue pigment, a pink pigment mixture (trade name “PE-D 06C579 Pink” manufactured by Dainichi Seika Kogyo Co., Ltd.) was used for the cover and the amount was as shown in Table 2 below. Similarly, golf balls of Example 4 and Comparative Examples 3 to 4 were obtained.

[Example 5 and Comparative Examples 5 to 6]
A yellow pigment mixture (trade name “PE-D 06E320 Yellow” manufactured by Dainichi Seika Kogyo Co., Ltd.) was used for the cover instead of the blue pigment, and the amount thereof was as shown in Table 3 below. Thus, golf balls of Example 5 and Comparative Examples 5 to 6 were obtained.

[Comparative Examples 7 to 8]
Golf balls of Comparative Examples 7 to 8 were obtained in the same manner as in Example 1 except that the ink composition shown in Table 4 below was used for the mark layer.

[Comparative Example 9]
A golf ball of Comparative Example 9 was obtained in the same manner as in Example 1 except that the cover was not mixed with a blue pigment and the ink composition shown in Table 4 below was used for the mark layer.

[Color measurement]
By the above-described method, the indices L ^* , a ^* and b ^* of the non-marked part and the marked part were measured. The results are shown in Tables 1 to 4 below.

[Identity]
The golf balls of Examples and Comparative Examples were placed on the lawn. Ten golfers visually observed these balls and evaluated the color difference from the commercially available white balls. Rating was performed based on the following criteria.
A: Number of golfers evaluated as having a large color difference 9 or more B: Number of golfers evaluated as having a large color difference 7 or more and 8 or less C: Number of golfers evaluated as having a large color difference 4 or more and 6 or less D: The number of golfers evaluated as having a large color difference is 3 or less. The results are shown in Tables 1 to 4 below.

[Visibility during flight]
A driver was attached to the swing machine. The golf balls of the examples and comparative examples were hit under the condition that the head speed was 45 m / sec. A golfer observed the trajectory and evaluated the visibility. Rating was performed based on the following criteria.
A: Number of golfers evaluated as good visibility is 9 or more B: Number of golfers evaluated as good visibility is 7 or more and 8 or less C: Number of golfers evaluated as good visibility is 4 6 or less D: The number of golfers evaluated as having good visibility is 3 or less. The results are shown in Tables 1 to 4 below.

[Visibility on the lawn]
The golf balls of Examples and Comparative Examples were placed on the lawn. The golf ball was observed by a golfer from a point 20 m away from the golf ball, and the visibility was evaluated. Rating was performed based on the following criteria.
A: Number of golfers evaluated as good visibility is 9 or more B: Number of golfers evaluated as good visibility is 7 or more and 8 or less C: Number of golfers evaluated as good visibility is 4 6 or less D: The number of golfers evaluated as having good visibility is 3 or less. The results are shown in Tables 1 to 4 below.

  As shown in Tables 1 to 4, the golf balls of the examples are excellent in distinguishability and visibility. From this evaluation result, the superiority of the present invention is clear.

  The present invention can be applied to golf balls having various structures.

FIG. 1 is a cross-sectional view showing a part of a golf ball according to an embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 2 ... Golf ball 4 ... Main body 6 ... Mark layer 8 ... Paint layer 10 ... Core 12 ... Cover 14 ... Dimple 16 ... Land 18 ... Mark part 20 ... Unmarked parts

Claims (4)

A golf ball having a mark portion and a non-mark portion on the surface thereof and comprising the following formulas (I) to (III):
50 ≦ L1 ≦ 80 (I)
L1 <L2 (II)
(A1 ² + b1 ² ) ^1/2 > (a2 ² + b2 ² ) ^1/2 (III)
(In these formulas, L1 represents a non-mark portion ^{L *,} L2 represents the ^{L *} of the mark portion, a1 represents the ^{a *} unmarked portion, a2 represents the ^{a *} mark portion, b1 non (The mark part represents b ^* , and b2 represents the mark part b ^* . L ^* , a ^* and b ^* are indices in the CIELAB display system.)   The golf ball according to claim 1, wherein L2 exceeds 65, and a difference between L2 and L1 (L2−L1) is 15 or more and 30 or less. The golf ball according to claim 1, wherein a difference between (a2 ² + b2 ² ) ^1/2 and (a2 ² + b2 ² ) ^1/2 is 5 or more. The golf ball according to claim 1, wherein (a2 ² + b2 ² ) ^1/2 is 15 or less.

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