JP2012035037A - Color golf ball - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a golf ball which has weatherability and prevents color change, has reassuring and psychologically calming effect on a golfer during play, and has suitable feel.SOLUTION: The golf ball is two-piece structure composed of a core and a cover, the surface of the ball is coated with a coating comprising a pearlescent pigment, and the ball satisfies the following conditions (i-viii): (i) a color difference ΔE* between the core and the ball of at least 30; (ii) the core has a transparency which is up to 10% in terms of total transmittance and up to 1.0% in terms of parallel transmittance; (iii) the core has a lightness L* value, expressed in the L*a*b* color system based on JIS Z8729, of at least 82; (iv) the ball has a lightness L* value of at least 50; (v) the lightness L* value of the ball≤the lightness L* value of the core; (vi) the cover has a thickness of from 0.1 to 2.1 mm; (vii) the cover has a transparency which is at least 50% in terms of total transmittance and at least 1.0% in terms of parallel transmittance; and (viii) the cover has a haze (H), mentioned in JIS K7105 (1981), of up to 98.

Description

  The present invention relates to a color golf ball having a fluorescent color. More specifically, the present invention relates to a fluorescent color golf ball having “high-grade color tone”, “performance” and “excellent discoloration resistance” that can be accepted by advanced golf players. About.

  In recent years, golf balls have begun to be favored from conventional white to yellow, pink and orange color balls. The reason is the psychological impression received from the visibility of the ball and the color of the ball.

  In addition, in the presence of high-performance golf balls, there are still many facts that golfers are seeking two-piece solid golf balls. The reason for this is that the two-piece solid golf ball can be provided at a relatively low cost by using a large portion of rubber, and is easy to obtain for golf users. Further, there is a means for thinning the cover to make an inexpensive two-piece solid golf ball.

  However, in the case of providing an inexpensive two-piece color golf ball, it has not been possible to provide a golf ball excellent in high-class feeling and discoloration resistance. Also, the technology for producing a two-piece color ball with a thin cover is still insufficient.

  Conventionally proposed golf balls have the following prior art.

  Japanese Patent Application Laid-Open No. 2007-21204 proposes a golf ball in which a transparent cover is formed by applying a paint containing glitter on a core, and a metallic texture and a three-dimensional impression of marking are sought. Yes, not intended for fluorescent color balls.

  Japanese Patent Application Laid-Open No. 2007-21205 proposes a golf ball in which the color difference ΔE between the inner layer and the ball is set to be as small as 30 or less. However, the appearance of this ball is dull and lacks the impact of the ball appearance. Furthermore, although it aims at blending a pearl pigment into a cover and exhibiting a pastel tone, it does not aim at high-quality vividness using a fluorescent pigment or fluorescent dye.

  In the golf ball described in US Patent Application No. 11/882216, the amount of the fluorescent pigment added to the cover is large, the transparency is insufficient, the color tone is too strong, and the high-class feeling is lost. Furthermore, the amount of fluorescent pigment added is increased, and the color fastness is inferior.

  The golf balls described in Japanese Patent Application Laid-Open No. 2007-144097 and U.S. Patent Application No. 11/299947 do not have a specific structure of cover transparency, and do not describe any sense of luxury.

  JP-A-10-155937 and JP-A-2000-254250 describe a ball having a pastel tone, but it is a very dark golf ball, visually uncomfortable, and high-class. No discoloration resistance.

  Japanese Patent Application Laid-Open No. 2000-24139 describes a color ball having a vivid color tone with a strong density and excellent visibility. However, the amount of the fluorescent pigment added to the cover is large, the transparency is insufficient, and the color tone is too strong.

Japanese Patent Application Laid-Open No. 2004-33594 describes a golf ball defined by L ^* a ^* b ^* display in order to improve visibility in blue, pink, and yellow, but has a high-class feel, performance, and discoloration resistance. It was not excellent in any aspect.

  Japanese Patent Application Laid-Open No. 2009-45347 gives a high-class feeling by increasing the saturation of the ball and coating the polarizing material, but there is no specific configuration for the transparency of the cover and the color of the background. As a result, it did not have a sufficiently high-class feeling.

JP 2007-21204 A JP 2007-21205 A JP 2007-144097 A Japanese Patent Laid-Open No. 10-155937 JP 2000-254250 A JP 2000-24139 A JP 2004-33594 A JP 2009-45347 A

  The present invention has been made in view of the above circumstances, and provides a two-piece color golf ball that prevents weather resistance and discoloration, and gives a golfer a sense of security during play, psychological calm, and appropriate feeling. The purpose is to provide.

  As a result of intensive studies to achieve the above object, the present inventors have made a two-piece solid golf with a thin cover in order to obtain a fluorescent color ball that is inexpensive, high-class, and excellent in resistance to discoloration. The above object can be achieved by a ball structure, a small amount of pigment or dye added to the cover layer, and a synergistic effect of the predetermined color of the base core and the predetermined transparency (HAZE value) of the cover. I found out.

  Furthermore, it has also been found that in a golf ball having the above structure, a high-class feeling can be improved by applying a pearl paint on the ball surface.

Accordingly, the present invention provides the following color golf balls.
[1] A two-piece color golf ball having a core and a cover on which a large number of dimples are formed on the outer surface. The surface of the ball is painted with a paint containing a pearl pigment and satisfies the following conditions: Color golf ball.
(I) The color difference ΔE ^* between the core and the ball is 30 or more. (Ii) The transparency of the core is 10% or less in total transmittance and 1.0% or less in parallel transmittance. (Iii) L ^* a ^* b ^* based on JIS Z8729 When expressed by the notation, the core lightness L ^* value is 82 or more (iv) the ball lightness L ^* value is 50 or more. (V) the ball lightness L ^* value ≦ the core lightness L ^* value (vi) the cover thickness. 0.1 to 2.1mm
(Vii) Cover transparency: total transmittance 50% or more, parallel transmittance 1.0% or more (viii) Haze (H) based on JIS K7105 (1981) of cover is 98% or less [2] (a ^{* 2} + B ^{* 2} ) The color golf ball according to [1], wherein the saturation C of the core represented by ^1/2 is 30 or less.
[3] The color golf ball according to [1] or [2], wherein in the coating material, a pearl pigment is blended in an amount of 0.1 to 0.6 parts by mass with respect to 100 parts by mass of the base resin.
[4] The color golf according to [1], [2] or [3], wherein in the coating material, a fluorescent brightening agent is blended in an amount of 0.05 to 0.5 parts by mass with respect to 100 parts by mass of the base resin. ball.
[5] The color golf ball according to [4], wherein the blending ratio of the optical brightener / pearl pigment is 0.08 to 5.0.
[6] The color golf ball according to any one of [1] to [5], wherein a pigment or dye is added to the cover in an amount of 0.001 to 0.4 parts by mass with respect to 100 parts by mass of the base resin. .
[7] The color golf ball according to [6], wherein calcium carbonate as a dye diffusing material is added to the cover in an amount of 1.0 part by mass or more based on 100 parts by mass of the base resin.
[8] The ratio of the total dimple area defined by the surface edge of the plane surrounded by the dimple edges to which the number of dimples is 330 or less is 80% of the ball sphere area assuming that no dimples exist. The color golf ball according to any one of [1] to [7].

  Although the two-piece color golf ball of the present invention is a fluorescent ball, it maintains transparency, has a high-class feeling, and can prevent weather resistance and discoloration. In addition, the color golf ball of the present invention can give the golfer a sense of security during play, psychologically calm, and give an appropriate feeling. Further, since the golf ball of the present invention is a two-piece golf ball with a thin cover, it can be manufactured at a relatively low cost.

1 is a schematic cross-sectional view of a two-piece solid golf ball showing an embodiment of the present invention. The dimple pattern no. 1 is a plan view of a ball showing 1. FIG. The dimple pattern no. 2 is a plan view of a ball showing 2. FIG. The dimple pattern no. 3 is a plan view of a ball showing 3. FIG. The dimple pattern no. 4 is a plan view of the ball showing 4. FIG. The dimple pattern no. FIG. 5 is a plan view of a ball showing 5. FIG. The dimple pattern no. 6 is a plan view of the ball showing 6. FIG. The dimple pattern no. 7 is a plan view of a ball showing 7. FIG.

Hereinafter, the present invention will be described in more detail.
The present invention has a ball structure including a core and a cover on which a large number of dimples are formed on the outer surface. For example, as shown in the ball cross-sectional view of FIG. 1, the internal ball structure of the present invention is a two-piece golf ball G including a core 1 and a cover 2 on which a large number of dimples D are formed. The golf ball of the present invention is low in cost and has the minimum performance required by many golfers. And the desired effect of this invention can be implement | achieved by the synergistic effect of the hue of the core mentioned above and the transparency of a cover. Here, in this invention, the desired effect of this invention is fully realizable by satisfy | filling the requirements of (i)-(viii) mentioned later.

The color golf ball of the present invention has the following conditions.
(I) The color difference ΔE ^* between the core and the ball is 30 or more. (Ii) The transparency of the core is 10% or less in total transmittance and 1.0% or less in parallel transmittance. (Iii) L ^* a ^* b ^* based on JIS Z8729 When expressed by the notation, the core lightness L ^* value is 82 or more (iv) the ball lightness L ^* value is 50 or more. (V) the ball lightness L ^* value ≦ the core lightness L ^* value (vi) the cover thickness. 0.1 to 2.1mm
(Vii) Cover transparency is total transmittance 50% or more, parallel transmittance 1.0% or more (viii) Haze (H) based on JIS K7105 (1981) of cover is 98% or less

Regarding the condition (i), the color difference ΔE ^* between the core and the ball is 30 or more. In other words, the color difference between the core and the ball is increased, and the cover has transparency as will be described later, so that a clear and high-quality color tone can be exhibited. In this case, based on the L ^* a ^* b ^* color system of “JIS Z8729”, L ^* values (lightness), a ^* and b ^* (chromaticity coordinates) are obtained,
ΔE ^* = {(ΔL ^* ) ² + (Δa ^* ) ² + (Δb ^* ) ² } ^1/2
Can be calculated. The color difference ΔE ^* represents the linear distance between two colors in this color space.

Regarding the condition (ii), the transparency of the core is required to be 10% or less in total transmittance and 1.0% or less in parallel transmittance. When the transparency of the core is larger than the above range, the degree of transparency of the entire ball increases and the color becomes worse. The total transmittance of the core is preferably more than 0%, and the upper limit is preferably 8% or less, more preferably 6% or less. Further, the parallel transmittance is preferably 0% or more, and the upper limit is preferably 0.4% or less, more preferably 0.06% or less. The above-mentioned “total transmittance” and “parallel transmittance” are calculated according to the standard in JIS K7105 (1981).

When the condition of (iii) is expressed by the L ^* a ^* b ^* display method based on JIS Z8729, the lightness L ^* value of the core needs to be 82 or more, preferably 84 or more, more preferably 86 or more. Yes, the upper limit is preferably 98 or less, more preferably 97 or less. The saturation C represented by (a ^{* 2} + b ^{* 2} ) ^1/2 of the core is not particularly limited, but is preferably 30 or less, more preferably 20 or less, and still more preferably 10 or less. is there. When the core is closer to white, the L ^* value as a ball becomes larger and the color becomes brighter. Therefore, the core is preferably white.

Regarding the condition (iv), the lightness L ^* value of the ball needs to be 50 or more, preferably 52 or more, more preferably 54 or more, and the upper limit is preferably 95 or less, more preferably 90 or less. It is. This is a necessary condition for maintaining the visibility, vividness and luxury of the ball.

(V) the conditions it is required to be lightness L ^* value of the lightness L ^* value ≦ the ball core about. This is because it is necessary to increase the L ^* value of the core in order to give the ball a sense of transparency and brightness. It is preferred that the difference between L ^* values and L ^* values of the ball core is 1 or more, more preferably 5 or more, more preferably 10 or more.

Regarding the condition (vi), the cover is formed to be relatively thin in the range of 0.1 to 2.1 mm. To achieve low cost, it is necessary to make the cover gauge thinner. The reason is that it is necessary to make the cover gauge thin in order to realize low cost. The cover has a thickness of 0.1 mm or more, preferably 0.2 mm or more, more preferably 0.3 mm or more, and the upper limit is 2.1 mm or less, preferably 1.8 mm or less, more preferably 1. 4 mm or less. When the cover is too thick than the above range, the transparency of the cover may be lost.

Regarding the condition (vii), the cover transparency is required to be 50% or more in total transmittance and 1.0% or more in parallel transmittance. This is because, in order to give a high-class feeling, it is necessary to finish the entire cover a little transparent and to have a clear color tone. In addition, the brightness of the core can be enhanced. The total transmittance of the cover is preferably 52% or more, more preferably 54% or more, and the upper limit is preferably 100% or less.

Regarding the condition (viii), the haze (H) based on JIS K7105 (1981) of the cover is required to be 98% or less. This is because by suppressing the degree of haze in the color tone of the cover layer, the entire ball has a clear color and leads to an increase in luxury. Here, said haze (H) means the haze (haze value) prescribed | regulated to JISK7105 (1981) standard as a photochemical performance test method of a plastic, and is calculated as follows.
Haze (H) = T _d / T _t × 100 (%)
(T _t : Total light transmittance, T _d : Diffuse transmittance)
In the present invention, the haze (H) of the cover is preferably 30% or more and 98% or less, more preferably 95% or less, and the diffuse transmittance (T _d ) of the cover is preferably 10 or more and 90%. Hereinafter, more preferably, it can be 20 or more and 80 or less.

  The core used in the present invention is based on a known rubber material such as 1,4-cis polybutadiene, and includes a co-crosslinking agent such as unsaturated carboxylic acid and its metal salt, zinc oxide, barium sulfate, etc. It can be obtained by vulcanizing a rubber composition blended with an organic filler such as dicumyl peroxide and 1,1-bis (t-butylperoxy) cyclohexane. In the present invention, the core diameter is not particularly limited. Moreover, there is no restriction | limiting in particular about the color tone of a core.

  The cover material used in the present invention is mainly formed of a resin material such as a thermoplastic resin or a thermoplastic elastomer, and the effects of the present invention can be obtained by blending various pigments and dyes in appropriate amounts. Can be realized.

  Here, the pigment or dye blended in the cover is not particularly limited. For example, a light collecting dye (pink), solvent yellow (dye), solvent orange (dye), anthraquinone (dye), phthalocyanine ( Dyes), fluorescent pigments (yellow), fluorescent pigments (pink), fluorescent pigments (orange), and the like, and known commercial products can be used.

  The amount of the pigment or dye added to the cover is preferably 0.001 to 0.4 parts by mass with respect to 100 parts by mass of the base resin. By suppressing the addition amount of the pigment or dye within the above range, the discoloration resistance of the entire ball can be improved.

As the dye contained in the cover, a blue dye is preferably used. In this case, the addition amount is 0.1 parts by mass or less with respect to 100 parts by mass of the base resin, and the L ^* value is 50 or more and the a ^* value is -20 to 20, b for the color of the cover surface. ^{* The} value is preferably −20 or less. In particular, the L ^* value is preferably 53 or more, more preferably 55 or more, and the upper limit is preferably 90 or less, more preferably 85 or less, and even more preferably 80 or less. This is because the golf course turf is green in summer and yellow in winter, and blue-based balls positioned opposite to the a ^* axis and b ^* axis with respect to green and yellow are most easily found. In addition, it is generally known that blue has a calming effect.

  Moreover, when mix | blending dye with a cover, it is preferable to employ | adopt calcium carbonate as a spreading | diffusion material of this dye, In that case, the compounding quantity shall be 1.0 mass part or more with respect to 100 mass parts of base resin. It is preferable. This is because calcium carbonate has a lower refractive index than titanium oxide, and thus the transparency of the entire cover increases. The blending amount is more preferably 1.3 parts by mass or more, still more preferably 1.5 parts by mass or more, and the upper limit is preferably 3 parts by mass or less, more preferably 2.8 parts by mass or less, even more preferably. Is 2.6 parts by mass or less.

  Usually, a large number of dimples are formed on the ball surface. In the present invention, the number of dimples formed on the ball surface is not particularly limited, but is preferably 250 or more and 330 or less, and the surface occupation ratio (SR) of the dimples formed on the ball surface is Although there is no particular limitation, it is preferably at least 80%, more preferably at least 90%, and the upper limit is preferably 98% or less, more preferably 95% or less. The reason is that by setting the number of dimples and the surface occupancy ratio within the above range, the bank surface (land portion) on the surface of the ball is relatively reduced, which gives more transparency and a higher-class feeling. is there.

  The cover surface can be painted with paint. When clear coating is used, it is preferable to use a two-component curable urethane coating. The two-component curable urethane coating is composed of a polyol component having a hydroxyl group and a polyisocyanate component having an isocyanate group.

  As the polyol, urethane, polyester, acrylic resin and the like are mainly used, but other resins such as epoxy resin can be used as necessary. On the other hand, as polyisocyanate, TDI, MDI, HDI, IPDI, NDI, PDI, XDI, and HXDI are modified by using one or a plurality, and in general, adduct, burette, and isocyanurate are used. Can take the form of

  The paint in the present invention uses a composition containing a pearl pigment in the base resin described above. In this case, the fluorescent whitening agent is used in an amount of 0.05 to 0.5 parts by mass and the pearl pigment is used in a mass ratio of 0.1 to 0.6 parts by mass with respect to 100 parts by mass of the base resin. And it is preferable to prepare so that the compounding ratio of a fluorescent whitening agent / pearl pigment may be 0.08-5.0. If the amount of the pearl pigment added is too large, the workability of the coating may be extremely reduced, the repulsion as a ball may be reduced, or the coating may be peeled off. In order to bring out the brightness and brightness of the ball, it is important to adjust the ratio of the fluorescent brightener and the pearl pigment. When the addition amount of the optical brightener and the pearl pigment is not appropriate, there is a risk that the appropriate brightness of the ball may be lost, and as a result, the effect of the present invention may not be obtained.

  Pearl pigments can be broadly classified into metal oxide-coated mica, basic lead carbonate, bismuth oxychloride, and natural fish phosphorus foil, but they are non-toxic and have the highest chemical stability. It is preferred to select oxide-coated mica. In general, titanium dioxide and iron oxide are often used as the metal oxide, and various colors and interference effects can be obtained by changing the coverage (the thickness of the coating layer). The greater the particle size of these pigments, the better the glitter. However, since the larger the particle size of the pigment, the more easily the glittering sedimentation occurs, it is desired to select a pigment having an appropriate particle size.

  The golf ball coated with the paint containing the pearl pigment as described above can reflect light at various angles, so that a high-class feeling is increased. Further, since the sunlight is sufficiently reflected, the golf ball can be found more easily.

  The film thickness of the coating with the paint is preferably 5 μm or more, more preferably 10 μm or more, and the upper limit is preferably 20 μm or less, more preferably 16 μm or less. If the coating is too thin, the durability of the coating may be impaired. On the other hand, if the coating film is too thick, the rebound of the ball will be reduced and the flight distance will not be produced, and the paint will be easily peeled off. As a result, the durability due to repeated impacts may be reduced.

  As the coating method, a publicly known method can be used. For example, the entire ball can be coated with various paints by spraying with the ball placed on the needle tip of the needle base.

  The golf ball of the present invention can be in compliance with golf regulations for competition purposes, and can be formed with a diameter of 42.67 mm or more and a weight of 45.93 g or less.

  For the production method of the present invention, a rubber composition mainly composed of polybutadiene or the like is vulcanized under known vulcanization conditions to produce a rubber cross-linked molded product (core), and then by a known method such as injection molding, A cover can be formed around the core to produce a two-piece solid golf ball. Normally, since many dimples are formed on the surface of the ball, the dimples are formed by the convex portions formed on the inner wall surface of the mold cavity simultaneously with the injection molding of the cover material which is the outermost layer. Become.

  EXAMPLES Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated concretely, this invention is not restrict | limited to the following Example.

[Examples 1 to 3, Comparative Examples 1 to 7]
The rubber compositions for Examples and Comparative Examples having the composition shown in Table 1 were prepared, kneaded with a kneader or a roll, and then a core was prepared under predetermined vulcanization conditions. Next, a cover material shown in Table 2 was injection molded around the core using an injection molding die to produce two-piece (two-layer structure) color golf balls of Examples and Comparative Examples. In addition, the number of the compounding of the core mixing | blending and resin mixing material in Table 1, 2 represents the mass part.

0.4 parts by mass of pearl pigment ("Xiallic T60-10WNT Crystal Silver" (manufactured by Merck & Co., Inc., particle size distribution: 5 to 30 μm) and 100 parts by mass of pearl coating base resin (two-component curable urethane) Composition containing 0.1 part by weight of whitening agent (“Hakkol PY-1800” (manufactured by Hakkol Chemical))
A composition in which 0.1 part by mass of a fluorescent whitening agent (“Hakkol PY-1800” (manufactured by Hakkol Chemical)) is blended with 100 parts by mass of a clear coating base resin (two-component curable urethane).

  The rubber vulcanization method is carried out at 155 ° C. for 15 minutes, and the “peroxide” is a mixture of 1,1-di (t-butylperoxy) cyclohexane and silica, trade name “Perhexa C- 40 ”(manufactured by NOF Corporation), the“ anti-aging agent ”is“ NOCRACK NS-6 ”(manufactured by Ouchi Shinsei Chemical Co., Ltd.).

HIMILAN 1557
Zinc neutralized ethylene-methacrylic acid copolymer manufactured by Mitsui DuPont Polychemical Co., Ltd.
HIMILAN 1855
Zinc-neutralized ethylene-methacrylic acid-acrylic acid ester copolymer manufactured by Mitsui DuPont Polychemical Co., Ltd.
HIMILAN 1605
Sodium neutralized ethylene-methacrylic acid copolymer manufactured by Mitsui DuPont Polychemical Co., Ltd.
HIMILAN 1706
Zinc neutralized ethylene-methacrylic acid copolymer manufactured by Mitsui DuPont Polychemical Co., Ltd.
Product name "Magnesium stearate G" manufactured by Magnesium Stearate NOF Co., Ltd.
Magnesium oxide manufactured by Kyowa Chemical Industry Co., Ltd.
Titanium oxide Ishihara Sangyo brand name "Taipeke R550"

  The physical properties of the cores, covers, and golf balls in the obtained Examples and Comparative Examples were evaluated according to the following criteria, and the evaluations are shown in Tables 3 and 4.

Total transmittance and parallel transmittance Measured using a light transmittance measuring device “TURBIDIMETER NDH5000W” (manufactured by Nippon Denshoku Industries Co., Ltd.), the total transmittance and parallel transmittance were determined based on JIS K7105. It shows that it is easy to let light pass, ie, transparency is so large that the value of total transmittance and parallel transmittance is large. On the contrary, the smaller the value, the harder it is to pass light, that is, the lower the transparency.
As for the haze / diffuse transmittance, it means that the smaller the value is, the more turbid, the less light diffusion, and the transparency.

Color difference ΔE ^*
It measured using the color difference meter (model SC-P, Suga Test Instruments Co., Ltd.), and calculated | required color difference (DELTA ⁾ E ^* based on L ^* a ^* b ^* color specification of JISZ8729. A larger value indicates a larger color difference, and a smaller value indicates a smaller color difference.

The discoloration-resistant ball was irradiated with a mercury lamp for 24 hours, and the degree of discoloration due to ultraviolet rays was observed and evaluated according to the following criteria.
○: Almost no discoloration
Δ: slightly discolored
×: Discolored greatly

Sensory evaluation was conducted according to the following criteria by 10 high- class golf players.
◎: Eight or more out of 10 felt “luxurious”
○: 5 to 7 out of 10 felt “classy”
△: 3 to 4 out of 10 felt “luxurious”
×: 2 or less of 10 people felt that “there was luxury”

Ease of viewing on the grass Ten senior golf players made a sensory evaluation according to the following criteria.
◎: Eight or more out of 10 felt it was easy to see on the grass
○: 5 to 7 out of 10 felt easy to see on the grass
Δ: 3 to 4 out of 10 felt easy to see on the grass
×: 2 or less of 10 people felt that it was easy to see on the grass

From Tables 3 and 4, each comparative example is inferior to the present invention (Example) in the following points.
In Comparative Examples 1, 2, and 3, since there is no pearl coating, a high-class feeling is not sufficient.
In Comparative Examples 4, 5, and 6, since the transparency of the cover is small, the discoloration resistance and high-grade feeling of the ball are deteriorated. In addition, since the cover has a large HAZE, the transparency is lost and the quality is inferior.
In Comparative Example 7, the color difference ΔE ^* between the core and the ball is 30 or less, the ball does not have a high-class feeling, and the legibility on the grass is not sufficient.

  In addition, various types of dimple patterns were applied to the ball structure of Example 1 to examine the transparency of the cover. These dimple patterns No. 1-No. 7 is shown in Table 5 and FIGS. Each dimple pattern is formed on the cover surface simultaneously with the injection molding of the cover resin material.

Dimple ratio (SR)
The ratio of the total dimple area defined by the surface edge of the plane surrounded by the edge of the dimple to the ball ball area assuming that no dimple exists.

  The transparency of the cover was evaluated. As a result of sensory evaluation by 10 senior golf players, it was the dimple pattern shown in FIG. 2 that eight or more players evaluated as “transparent”, and then five to seven players had “transparency”. The dimple patterns shown in FIGS. 3, 4 and 5 were evaluated. Next, 3 to 4 persons evaluated “transparency” as the dimple pattern in FIG. 6, and 2 persons or less had “transparency”. The dimple patterns in FIGS. 7 and 8 were evaluated.

1 Core 2 Cover D Dimple G Golf ball

Claims (8)

A two-piece color golf ball having a core and a cover on which a large number of dimples are formed on the outer surface, and the surface of the ball is painted with a paint containing a pearl pigment and satisfies the following conditions: Golf ball.
(I) The color difference ΔE ^* between the core and the ball is 30 or more. (Ii) The transparency of the core is 10% or less in total transmittance and 1.0% or less in parallel transmittance. (Iii) L ^* a ^* b ^* based on JIS Z8729 When expressed by the notation, the core lightness L ^* value is 82 or more (iv) the ball lightness L ^* value is 50 or more. (V) the ball lightness L ^* value ≦ the core lightness L ^* value (vi) the cover thickness. 0.1 to 2.1mm
(Vii) Cover transparency is total transmittance 50% or more, parallel transmittance 1.0% or more (viii) Haze (H) based on JIS K7105 (1981) of cover is 98% or less The color golf ball according to claim 1, wherein the saturation C of the core represented by (a ^{* 2} + b ^{* 2} ) ^1/2 is 30 or less.   The color golf ball according to claim 1 or 2, wherein in the coating material, a pearl pigment is blended in an amount of 0.1 to 0.6 parts by mass with respect to 100 parts by mass of the base resin.   The color golf ball according to claim 1, 2, or 3, wherein in the coating material, a fluorescent brightening agent is blended in an amount of 0.05 to 0.5 parts by mass with respect to 100 parts by mass of the base resin.   The color golf ball according to claim 4, wherein the blending ratio of the optical brightener / pearl pigment is 0.08 to 5.0 by mass ratio.   The color golf ball according to claim 1, wherein a pigment or a dye is added to the cover in an amount of 0.001 to 0.4 parts by mass with respect to 100 parts by mass of the base resin.   The color golf ball according to claim 6, wherein calcium carbonate as a dye diffusing material is added to the cover in an amount of 1.0 part by mass or more with respect to 100 parts by mass of the base resin.   The number of dimples is 330 or less, and the total dimple area defined by the surface edge of the plane surrounded by the dimple edges accounts for 80% or more of the ball sphere area assuming that no dimples exist. The color golf ball according to claim 1.

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