JP2022100084A - Golf ball - Google Patents

Abstract

To provide a golf ball which has high visibility, and has no discomfort in shot.SOLUTION: A golf ball 1 has a core, and a cover arranged on outside of the core. A surface of the golf ball has a first area S1 having a first color, and a second area S2 having a second color. A hue of the first color is H1 expressed using an H value by an HSL color space, a hue of the second color is H2 expressed using an H value by the HSL color space, and the H1 and the H2 satisfy a mathematical expression (1) or (2). The mathematical expression (1) is 0≤|H1-H2|≤60 and the mathematical expression (2) is 300≤|H1-H2|≤360.SELECTED DRAWING: Figure 2

Description

The present invention relates to golf balls, and more particularly to color golf balls.

Golf balls are usually white. In bad weather such as rain, cloudy, fog and dim conditions, it is difficult to follow the trajectory of the white golf ball and see where the golf ball falls. Also, when a white golf ball is parked on a dead lawn, it is difficult to find the golf ball even if it is near the golf ball. Recently, the number of golf players who demand fashionability from golf balls is increasing. Under such circumstances, color golf balls have been proposed in order to satisfy the demands such as fashionable appearance and visibility in bad weather.

In Patent Document 1, a first hemispherical shell and a core mounted in the recess of the lower mold having a hemispherical recess are covered with a second hemispherical shell different from the first hemispherical shell. In a method for manufacturing a two-tone golf ball, which is formed into a spherical shape and is covered with an upper mold and heat-pressed, for horizontal locking to the edge of a lower mold recess in the vicinity of the opening end surface of the first hemispherical shell. A method for manufacturing a golf ball, which is characterized by providing a protrusion of the golf ball, is disclosed.

Patent Document 2 discloses a golf ball including a core and a cover, the cover of which is composed of a first hemisphere and a second hemisphere, and the specifications of the first hemisphere are different from the specifications of the second hemisphere. ing. Even if the first hemisphere is made of the first resin composition and the second hemisphere is made of the second resin composition, and the composition of the first resin composition is different from the composition of the second resin composition. good.

In Patent Document 3, in a golf ball including a core having at least one layer and a cover having at least one layer, the outermost layer of the core is two hemispherical portions of different colors formed from a rubber composition. And the boundary between the hemispheres is provided along the large circle of the outermost layer of the core as a color boundary, and at least one of the hemispheres contains a fluorescent colorant or a brilliant agent. A golf ball is characterized in that the cover is formed of a transparent or translucent thermoplastic resin composition, and at least one layer of the cover contains at least one of a fluorescent whitening agent, a fluorescent colorant, and a brightening agent. It has been disclosed.

Patent Document 4 is characterized in that the surface of the inner core is covered with a plurality of outer shells having different colors to form an outer shell layer, and the outer surface is partitioned by the difference in the color of the outer shell layer. The golf ball to play is disclosed.

Patent Document 5 discloses a golf ball having a multi-color layer obtained by injection molding a first material and a second material, respectively.

Patent Document 6 discloses a golf ball having at least two layers, and each layer has at least two different regions, so that the appearance of the entire golf ball is multicolored.

Patent Document 7 discloses golf balls having different color tones of the first hemisphere cover and the second hemisphere cover.

Japanese Unexamined Patent Publication No. 63-388476 Japanese Unexamined Patent Publication No. 2013-183833 Japanese Unexamined Patent Publication No. 2017-118950 Published Practical Publication No. 59-64165 US Pat. No. 7,862,760 US Pat. No. 8,915,802 US Pat. No. 9067105

An object of the present invention is to provide a golf ball having high visibility and less discomfort at the time of a shot.

The golf ball of the present invention that has been able to solve the above problems is a golf ball having a core and a cover arranged on the outside of the core.
The surface of the golf ball has a first region of the first color and a second region of the second color.
The hue of the first color is H1 represented by using the H value according to the HSL color space.
The hue of the second color is H2 represented by using the H value according to the HSL color space.
A golf ball characterized in that the H1 and the H2 satisfy the following mathematical formula (1) or mathematical formula (2).
0 ≦ ｜ H1-H2 ｜ ≦ 60 (1)
300 ≦ ｜ H1-H2 ｜ ≦ 360 (2)

When the relationship of the formula (1) or the formula (2) is satisfied, the first color in the first region and the second color in the second region are similar colors. As a result, there is less discomfort at the time of shot, and it is rough and easy to find.

According to the present invention, it is possible to obtain a golf ball having high visibility and less discomfort at the time of a shot.

The front view explaining the golf ball which concerns on one Embodiment of this invention. The plan view explaining the golf ball which concerns on one Embodiment of this invention. The front view explaining the golf ball which concerns on one Embodiment of this invention. The plan view explaining the golf ball which concerns on one Embodiment of this invention. A partially cutaway sectional view showing a golf ball according to an embodiment of the present invention.

The golf ball of the present invention is a golf ball having a core and a cover arranged on the outside of the core.
The surface of the golf ball has a first region of the first color and a second region of the second color.
The hue of the first color is H1 represented by using the H value according to the HSL color space.
The hue of the second color is H2 represented by using the H value according to the HSL color space.
A golf ball characterized in that H1 and H2 satisfy the following mathematical formula (1) or mathematical formula (2).
0 ≦ ｜ H1-H2 ｜ ≦ 60 (1)
300 ≦ ｜ H1-H2 ｜ ≦ 360 (2)

The surface of the golf ball of the present invention has a first region of the first color and a second region of a second color different from the first color. It is preferable that each of the first region and the second region is a region composed of a single color.

The hue of the first color in the first region is H1 represented by using the H value according to the HSL color space.
The hue of the second color in the second region is H2 represented by using the H value in the HSL color space, and the H1 and H2 satisfy the following mathematical formula (1) or mathematical formula (2).
0 ≦ ｜ H1-H2 ｜ ≦ 60 (1)
300 ≦ ｜ H1-H2 ｜ ≦ 360 (2)
In the present invention, the "hue of the first color in the first region" is simply referred to as the "hue of the first region", and the "hue of the second color of the second region" is simply referred to as the "hue of the second region". May be referred to.

When the hue H1 in the first region and the hue H2 in the second region satisfy the above formula (1), the absolute value of the difference between the hue H1 in the first region and the hue H2 in the second region | H1- For H2 |, 0 or more is preferable, more than 0 is more preferable, 5 or more is further preferable, 7 or more is particularly preferable, 60 or less is preferable, 55 or less is more preferable, and 50 or less is further preferable. This is because if the absolute value | H1-H2 | is within the above range, the visibility is high and the effect of eliminating a sense of discomfort at the time of a shot can be obtained.

When the hue H1 in the first region and the hue H2 in the second region satisfy the above formula (2), the absolute value of the difference between the hue H1 in the first region and the hue H2 in the second region | H1- For H2 |, 300 or more is preferable, 305 or more is more preferable, 307 or more is further preferable, 360 or less is more preferable, 355 or less is more preferable, and 350 or less is further preferable. This is because if the absolute value | H1-H2 | is within the above range, the visibility is high and the effect of eliminating a sense of discomfort at the time of a shot can be obtained.

The hue of the first color in the first region is H1 represented by using the H value according to the HSL color space, and the H1 is preferably 20 or more, more preferably 30 or more, and 40 or more. It is more preferably 340 or less, more preferably 330 or less, and even more preferably 320 or less.

The saturation of the first color in the first region is S1 represented by using the S value according to the HSL color space, and the S1 is preferably 40 or more, more preferably 45 or more, and more preferably 50 or more. It is more preferably 100 or less, more preferably 95 or less, and further preferably 90 or less.

The luminance of the first color in the first region is L1 expressed by using the L value according to the HSL color space, and the L1 is preferably 30 or more, more preferably 40 or more, and more preferably 50 or more. It is more preferably 100 or less, more preferably 90 or less, and even more preferably 80 or less.

The hue of the second color in the second region is H2 represented by using the H value according to the HSL color space, and the H2 is preferably 0 or more, more preferably 5 or more, and 10 or more. It is more preferably 360 or less, and more preferably 350 or less.

The saturation of the second color in the second region is S2 represented by using the S value according to the HSL color space, and the S2 is preferably 40 or more, more preferably 50 or more, and 60 or more. It is more preferably 100 or less, more preferably 90 or less, and even more preferably 80 or less.

The luminance of the second color in the second region is L2 expressed by using the L value according to the HSL color space, and the L2 is preferably 30 or more, more preferably 40 or more, and more preferably 50 or more. It is more preferably 100 or less, more preferably 90 or less, and even more preferably 80 or less.

The first color in the first region is not particularly limited, but is preferably a color selected from the group consisting of white, yellow, orange, blue, red, pink, green, and black. The second color in the second region is not particularly limited as long as it is a color different from the first color in the first region, and is selected from the group consisting of white, yellow, orange, blue, red, pink, green, and black. It is preferable that the color is yellow.

The area of the one region on the surface of the golf ball is preferably 10% or more, more preferably 20% or more, further preferably 30% or more, and further preferably 90% or less of the surface area of the golf ball. Is more preferable, 80% or less is more preferable, and 70% or less is further preferable.

The area of the second region on the surface of the golf ball is preferably 10% or more, more preferably 20% or more, further preferably 30% or more, and further preferably 90% or less of the surface area of the golf ball. It is preferably 80% or less, more preferably 70% or less, and even more preferably 70% or less.

The area ratio between the first region and the second region is not particularly limited, but is preferably 20/80 or more, more preferably 30/70 or more, particularly preferably 50/50, preferably 80/20 or less, and 70/30. The following is more preferable.

The shapes of the first region and the second region are not particularly limited, and examples thereof include polygonal shapes such as triangles, quadrangles, pentagons, and hexagons, trapezoids, circles, and ellipses in a plan view. In general, character strings such as a product name and a ball number provided on the surface of a golf ball do not correspond to the first region and the second region of the present invention.

The first region and the second region may be provided at only one place on the surface of the golf ball, or may be provided at a plurality of places, respectively.

In the present invention, when the golf ball surface is formed only from the first region and the second region, for example, when the first region has a specific shape, the second region is a region other than the first region. For example, if the first region has a polygonal shape such as a triangle, a quadrangle, a pentagon, or a hexagon, or a trapezoid, a circle, or an ellipse in a plan view, the second region is other than the first region on the golf ball surface. Area of.

Further, in a preferred embodiment of the present invention, the first region and the second region are regions surrounded by two boundary lines connecting the first pole and the second pole of the golf ball surface, respectively, and the first region. It is a continuous region from the pole point to the second pole point. Here, the first pole and the second pole are the intersections of the central axis passing through the center of the golf ball and the surface of the golf ball, respectively. It is preferable that the first region and the second region are hemispherical, respectively.

FIG. 1 is an explanatory diagram illustrating a preferred embodiment of the present invention with respect to the first region and the second region. The golf ball 1 has a first pole point P1 and a second pole point P2 in which an axis passing through the center of the golf ball intersects the surface of the golf ball. FIG. 1 is a front view in which the first pole P1 and the second pole P2 are arranged in the vertical direction and the first region is arranged in the front. FIG. 2 is a plan view seen from the first pole P1. The first region S1 and the second region S2 are regions surrounded by two boundary lines L1 and L2 connecting the first pole point P1 and the second pole point P2 on the golf ball surface, respectively, from the first pole point. It is a region continuous to the second pole. In the aspects of FIGS. 1 and 2, the first region S1 forms a one-third region of the golf ball surface, and the second region S2 forms a two-thirds region of the golf ball surface.

FIG. 3 is an explanatory diagram illustrating another preferred embodiment of the present invention with respect to the first region and the second region. FIG. 3 is a front view in which the first pole P1 and the second pole P2 are arranged in the vertical direction, and the boundary line L1 between the first region S1 and the second region S2 is arranged in the front. FIG. 4 is a plan view seen from the first pole P1. The golf ball surface is composed of a first region S1 and a second region S2, and the first region S1 and the second region S2 are hemispherical, respectively.

The first region and the second region may be formed by a colored coating film, or may be formed by a colored cover, respectively. For example, an embodiment in which the first region and the second region are formed by a colored cover, an embodiment in which the first region and the second region are formed by a colored coating film, or the above-mentioned embodiment. One of the first region and the second region may be formed by a colored cover, and the other of the first region and the second region may be formed by a colored coating film.

The golf ball of the present invention may have at least one intermediate layer between the core and the cover. The hue of the outermost layer of the intermediate layer is H0 represented by using the H value according to the HSL color space, and one of | H0-H1 | and | H0-H2 | is less than 10 and the other is 10 or more. It is preferable to have. When there are a plurality of intermediate layers, the outermost layer is the intermediate layer located closest to the cover side. In the case of a monolayer intermediate layer, the outermost layer is a monolayer intermediate layer.

Of | H0-H1 | and | H0-H2 |, one is preferably less than 10, more preferably 7 or less, and even more preferably 4 or less. If one of | H0-H1 | and | H0-H2 | is less than 10, the color development is good and the outline of the dimples can be made inconspicuous.

Of | H0-H1 | and | H0-H2 |, the other is preferably 10 or more, preferably 20 or more, more preferably 30 or more, and preferably 85 or less. It is more preferably 75 or less, and further preferably 65 or less. If the other of | H0-H1 | and | H0-H2 | is 10 or more, the distinction between the first region and the second region becomes clear while maintaining the color-developing property.

The hue of the outermost layer of the intermediate layer is H0 represented by using the H value according to the HSL color space, and the H0 is preferably 0 or more, more preferably 10 or more, and 20 or more. Is more preferably 360 or less, more preferably 350 or less, and even more preferably 340 or less.

The saturation of the outermost layer of the intermediate layer is S0 expressed by using the S value by the HSL color space, and the S0 is preferably 30 or more, more preferably 40 or more, and more preferably 50 or more. Is more preferably 100 or less, more preferably 97 or less, and even more preferably 94 or less.

The luminance of the outermost layer of the intermediate layer is L0 expressed by using the L value by the HSL color space, and the L0 is preferably 30 or more, more preferably 40 or more, and more preferably 50 or more. Is more preferably 100 or less, more preferably 97 or less, and even more preferably 94 or less.

The color of the outermost layer of the golf ball surface and the intermediate layer of the present invention can be determined by the L * value, the a * value, and the b * value in the CIELAB color system. The L * value, a * value, and b * value in the CIELAB color system can be measured according to JIS-Z-8701 or JIS-Z-8728. For the measurement, it is preferable to use a color difference meter CM-350d manufactured by Minolta, which employs a stimulus value direct reading method. The tristimulus values X, Y, Z are converted into L *, a *, b * as follows.
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 ]}
XN, YN, ZN: Tristimulus values in the X, Y, Z system of the perfect diffuse reflection surface

In the present invention, the L * value, a * value, and b * value obtained as described above are converted into H value (hue), S value (saturation), and S value (saturation) in the HSL color space by using a color code conversion tool. Convert to L value (brightness). As the color code conversion tool, for example, the one described on the following website can be used.
https://syncer.jp/color-converter

[Golf ball material]
The golf ball of the present invention has a core, at least one intermediate layer covering the core, and a cover covering the intermediate layer. Hereinafter, the materials constituting each component of the golf ball will be described.

[Middle layer and cover]
The intermediate layer and / or cover of the golf ball of the present invention is formed from a composition containing a resin component. In the present invention, the resin composition forming the intermediate layer may be referred to as an intermediate layer composition, and the resin composition forming the cover may be referred to as a cover composition. Examples of the resin component include ionomer resin, a thermoplastic polyurethane elastomer marketed under the trade name "Elastoran (registered trademark)" from BASF Japan Co., Ltd., and the trade name "Pebax (registered trademark)" from Alchema Co., Ltd. , A thermoplastic polyamide elastomer marketed under the trade name "Hytrel (registered trademark)" from Toray DuPont Co., Ltd., under the trade name "Tefablock" from Mitsubishi Chemical Co., Ltd. Examples thereof include commercially available thermoplastic styrene elastomers.

The ionomer resin is, for example, an olefin in which at least a part of the carboxyl group in the binary copolymer of an olefin and an α, β-unsaturated carboxylic acid having 3 to 8 carbon atoms is neutralized with a metal ion. At least a part of the carboxyl group of the ternary copolymer of α, β-unsaturated carboxylic acid having 3 to 8 carbon atoms and α, β-unsaturated carboxylic acid ester is neutralized with metal ions, or , These mixtures can be mentioned. As the olefin, an olefin having 2 to 8 carbon atoms is preferable, and examples thereof include ethylene, propylene, butene, pentene, hexene, heptene, and octene, and ethylene is particularly preferable. Examples of the α, β-unsaturated carboxylic acid having 3 to 8 carbon atoms include acrylic acid, methacrylic acid, fumaric acid, maleic acid, crotonic acid and the like, and acrylic acid or methacrylic acid is particularly preferable. As the α, β-unsaturated carboxylic acid ester, for example, methyl, ethyl, propyl, n-butyl, isobutyl ester such as acrylic acid, methacrylic acid, fumaric acid, maleic acid and the like are used, and in particular, acrylic acid ester. Alternatively, a methacrylic acid ester is preferable. Among these, the ionomer resin includes a metal ion neutralized product of an ethylene- (meth) acrylic acid binary copolymer and a ternary copolymer of ethylene- (meth) acrylic acid- (meth) acrylic acid ester. Metal ion neutralized products are preferred.

The resin composition constituting the intermediate layer or cover of the golf ball of the present invention preferably contains a thermoplastic polyurethane elastomer or an ionomer resin as a resin component. When an ionomer resin is used, it is also preferable to use a thermoplastic styrene elastomer in combination. The content of the polyurethane or ionomer resin in the resin component of the resin composition is preferably 50% by mass or more, more preferably 60% by mass or more, still more preferably 70% by mass or more.

In a preferred embodiment of the invention, the intermediate layer is formed from a composition containing an ionomer resin and the cover is formed from a composition containing a thermoplastic urethane elastomer.

[Dyes and / or Pigments]
The intermediate layer and / or cover of the golf ball of the present invention preferably contains a dye and / or a pigment, and more preferably contains a fluorescent dye and / or a fluorescent pigment. The fluorescent dye may be either organic or inorganic, and may be any commercially available fluorescent dye. Examples of the fluorescent dye include thioxanthene derivatives, santhene derivatives, perylene derivatives, peryleneimide derivatives, coumarin derivatives, thioindigo derivatives, naphthalimide derivatives, and methine derivatives.

In a preferred embodiment, the melting point of the fluorescent dye and / or the fluorescent pigment is 180 ° C. or lower, more preferably 175 ° C. or lower, still more preferably 170 ° C. or lower, preferably at least 135 ° C. or higher, and more preferably 140 ° C. ° C. or higher, more preferably 145 ° C. or higher. When the melting point of the fluorescent dye and / or the fluorescent pigment is within the above range, the fluorescent dye and / or the fluorescent pigment can be mixed and dispersed in the resin component at a relatively low temperature. Since discoloration due to high temperature during processing is less likely to occur, a desired color tone can be easily obtained.

The fluorescent dye is not particularly limited, but a specific example may be exemplified by a trade name: Lumogen F Orange.TM. 240 (manufactured by BASF); Lumogen F Yellow.TM. 083 (manufactured by BASF); Hostasol Yellow.TM. 3G (Hoechst-Celanese); Oraset Yellow.TM. 8GF (Ciba-Geigy); Fluorol 088.TM. (BASF); Thermolast F Yellow.TM. 084 (BASF); .TM. D-304 (manufactured by DayGlo); Mohawk Yellow.TM. D-299 (manufactured by DayGlo); Potomac Yellow.TM. D-838 (manufactured by DayGlo); Polyfast Brilliant Red.TM. ) And other yellow fluorescent dyes can be mentioned.

Examples of the fluorescent pigment include a pigment in which a fluorescent dye is dispersed in a polymer material, a pigment obtained by molding a fluorescent dye into particles, and the like. The fluorescent pigment is not particularly limited, but is, for example, ZQ-11, ZQ-12, ZQ-13, ZQ-14, ZQ-15, ZQ-16, ZQ-17-N, ZQ manufactured by Deigro Color Co., Ltd. -18, ZQ-19, ZQ-21, GPL-11, GPL-13, GPX-14, GPL-15, GPX-17, GPL-19, GPL-21, and FZ-2000 series manufactured by Shinroihi. Examples include the FZ-5000 series, the FZ-6000 series, the FZ-3040 series, and the FX-300 series.

Examples of the polymer material for dispersing the fluorescent dye include benzoguanamine resin, acrylic resin, polyester resin and the like.

In a preferred embodiment, the cover and at least one intermediate layer contain a dye and / or a pigment, preferably 0.5 parts by mass or more, more preferably 0.6 parts by mass or more, still more preferably, with respect to 100 parts by mass of the resin component. Is contained in an amount of 0.7 parts by mass or more, preferably 7 parts by mass or less, more preferably 6 parts by mass or less, still more preferably 5 parts by mass or less, still more preferably 4 parts by mass or less. If the content is too high, the color of the golf ball becomes too deep and the color tone becomes dull, and if the content is too low, the desired color tone cannot be obtained.

Since the fluorescent dye and / or the fluorescent pigment has low light stability, it is preferable to use an ultraviolet absorber or a light stabilizer. The ultraviolet absorber or light stabilizer is not particularly limited, and any commercially available product may be used. Examples thereof include an ultraviolet absorber such as a salicylic acid derivative, a benzophenone derivative, a benzotriazole derivative, a cyanoacrylate derivative, a triazine derivative and a nickel complex, and a light stabilizer such as a hindered amine derivative.

Phenylsalicylate, pt-butylphenylsalicylate, p-octylphenylsalicylate and the like as UV absorbers for salicylic acid derivatives; 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxy as UV absorbers for benzophenone derivatives. Benzophenone, 2-hydroxy-4-octyloxybenzophenone, 2,2-dihydroxy-4,4'-methoxybenzophenone, etc .; As an ultraviolet absorber of the benzotriazole derivative, 2- (2'-hydroxy-5'-methylphenyl) ) Benzotriazole, 2- (2'-hydroxy-5'-t-butylphenyl) benzotriazole, 2- (2'-hydroxy-3'-t-butyl-5'-methylphenyl) -5-chlorobenzotriazole , 2- [2-Hydroxy-3,5-bis (α, α'-dimethylbenzyl) phenyl] -2H-benzotriazole, 2- (5-methyl-2-hydroxyphenyl) benzotriazole, etc .; Examples of the ultraviolet absorber include 2-ethylhexyl-2-cyano-3,3'-diphenyl acrylate, ethyl-2-cyano-3,3'-diphenyl acrylate and the like; and as an ultraviolet absorber of the triazine derivative, 2- (4). , 6-Diphenyl-1,3,5-triazine-2-yl) -5 [(hexyl) oxy] -phenol, 2,4-bis (2-hydroxy-4-butyloxyphenyl) -6- (2, 4-Bis-butyloxyphenyl) -1,3,5-triazine, 2-(4-{[2-hydroxy-3- (2'-ethyl) hexyl] oxy} -2-hydroxyphenyl) -4,6 -Bis (2,4-dimethylphenyl) -1,3,5-triazine and the like can be mentioned. Specifically, Sumitomo Chemical's "Sumithorpe 130" and "Sumithorpe 140" (both are benzophenone-based UV absorbers), and Ciba Specialty Chemicals' "TINUVIN 234" and "Chinubin 900". , "Chinubin 326", "Chinubin P" (both benzotriazole type), "Uvinul N-35" (cyanoacrylate type) manufactured by BASF, "Chinubin 1577", "Chinubin 460" manufactured by Ciba Specialty Chemicals. , "Chinubin 405" (triazine type) and the like. One of these ultraviolet absorbers may be used alone, or two or more thereof may be used in combination. The ultraviolet absorbers that can be used in the present invention are not limited to these, and any conventionally known ultraviolet absorber can be used.

As a light stabilizer such as a hindered amine derivative, bis (1,2,2,6,6-pentamethyl-4-piperidyl) {[3,5-bis (1,1'-dimethylethyl) -4-hydroxyphenyl] Methyl} butylmalonate, 1- {2- [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionyloxy] ethyl} -4- [3- (3,5-di-t-) Butyl-4-hydroxyphenyl) propionyloxy] -2,2,6,6-tetramethylpiperidine and the like can be mentioned. Specific examples thereof include "Sanol LS-2626" and "Chinubin 144" manufactured by Ciba Specialty Chemicals.

The content of the ultraviolet absorber or the light stabilizer is preferably 0.02 part by mass or more, more preferably 0.04 part by mass or more, and 2 by mass with respect to 100 parts by mass of the resin component of the intermediate layer or the cover. It is preferably 1 part by mass or less, more preferably 1 part by mass or less. When the content of the ultraviolet absorber or the light stabilizer is within the above range, discoloration due to exposure to sunlight can be effectively suppressed.

(Titanium oxide)
The intermediate layer and / or cover may contain titanium oxide. Combining a fluorescent pigment with a small amount of titanium oxide provides a translucent cover with bright colors. Since the titanium oxide has high hiding power, the content of titanium oxide is preferably 0.001 part by mass or more, more preferably 0.002 part by mass or more, and 0.005 part by mass with respect to 100 parts by mass of the resin component. The above is more preferable, 0.7 parts by mass or less is preferable, 0.5 parts by mass or less is preferable, and 0.4 parts by mass or less is further preferable. When the content of titanium oxide is 0.001 part by mass or more, a translucent cover having a bright color is obtained, and when the content of titanium oxide exceeds 0.7 parts by mass, the cover exhibits concealing property. Tend.

If the hiding power of the intermediate layer and / or the cover is increased to increase the degree of whiteness, the content of titanium oxide can be increased. In this case, the content of titanium oxide is preferably more than 0.7 parts by mass, more preferably 1 part by mass or more, and 10 parts by mass with respect to 100 parts by mass of the resin component constituting the intermediate layer and / or the cover. It is preferably parts or less, and more preferably 8 parts by mass or less. By setting the content of titanium oxide to more than 0.7 parts by mass, the hiding power of the intermediate layer and / or the cover can be enhanced. Further, when the content of titanium oxide exceeds 10 parts by mass, the durability of the obtained intermediate layer and / or cover may decrease.

(Other ingredients)
In addition to the above-mentioned components, the intermediate layer and / or cover contains mass modifiers such as zinc oxide, calcium carbonate and barium sulfate, dispersants, antiaging agents, fluorescent whitening agents, lubricants, light stabilizers, etc. And / or may be contained within a range that does not impair the performance of the cover.

The golf ball of the present invention preferably has a coating film that covers the cover. When the golf ball of the present invention has a coating film, the color of the surface of the golf ball can be obtained by measuring the surface of the coating film provided on the surface of the golf ball. Examples of the coating film include a colorless and transparent clear coating film, a colored opaque coating film, and a matte-like coating film.

When the golf ball has a colorless and transparent clear coating film, the color of the cover is reflected in the first color of the first region and the second color of the second region on the surface of the golf ball. When the golf ball has a colored opaque coating film or a matte coating film, the color tone of the golf ball surface is affected by the coating film.

The colored opaque coating film preferably contains, for example, a resin component and a dye and / or a pigment. The matte coating film preferably contains, for example, a resin component and a filler.

The resin component constituting the coating film is not particularly limited, and acrylic resin, epoxy resin, polyurethane, polyester, cellulosic resin and the like can be used, but it is preferable to use two-component curable polyurethane described later. This is because when a two-component curable polyurethane is used, a coating film layer having further excellent durability can be obtained.

(Polyurethane)
As the polyurethane, a polyurethane (two-component curable polyurethane) obtained by reacting a polyol composition with a polyisocyanate composition is preferable.

(Polyol composition)
The polyol composition contains a polyol compound. Examples of the polyol compound include compounds having two or more hydroxy groups in the molecule. Examples of the polyol compound include a compound having a hydroxy group at the end of the molecule and a compound having a hydroxy group other than the end of the molecule. The polyol compound may be used alone or in combination of two or more.

Examples of the compound having a hydroxy group at the end of the molecule include a low molecular weight polyol having a molecular weight of less than 500 and a high molecular weight polyol having a number average molecular weight of 500 or more. Examples of the low molecular weight polyol include diols such as ethylene glycol, diethylene glycol, triethylene glycol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, and 1,6-hexanediol; glycerin and trimethylol. Triols such as propane and hexanetriol can be mentioned. Examples of the high-molecular-weight polyol include polyether polyols, polyester polyols, polycaprolactone polyols, polycarbonate polyols, urethane polyols, acrylic polyols and the like. Examples of the polyether polyol include polyoxyethylene glycol (PEG), polyoxypropylene glycol (PPG), polyoxytetramethylene glycol (PTMG) and the like. Examples of the polyester polyol include polyethylene adipate (PEA), polybutylene adipate (PBA), polyhexamethylene adipate (PHMA) and the like. Examples of the polycaprolactone polyol include poly-ε-caprolactone (PCL). Examples of the polycarbonate polyol include polyhexamethylene carbonate and the like.

The polyol composition preferably contains a urethane polyol as a polyol component. Urethane polyols are synthesized by the reaction of polyisocyanates with polyols. The polyisocyanate used for the synthesis of the urethane polyol is not particularly limited as long as it has two or more isocyanate groups, and is, for example, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, and 2,4-toluene diisocyanate. Mixture of 2,6-toluene diisocyanate (TDI), 4,4'-diphenylmethane diisocyanate (MDI), 1,5-naphthylene diisocyanate (NDI), 3,3'-bitrylene-4,4'-diisocyanate (TODI) , Aromatic polyisocyanates such as xylylene diisocyanate (XDI), tetramethylxylylene diisocyanate (TMXDI), paraphenylenedi isocyanate (PPDI); 4,4'-dicyclohexylmethane diisocyanate (H ₁₂ MDI), hydrogenated xylylene diisocyanate (H 12 MDI) H ₆ XDI), hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), norbornene diisocyanate (NBDI) and other alicyclic polyisocyanates or aliphatic polyisocyanates may be used. .. Of these, non-yellowing polyisocyanates (TMXDI, XDI, HDI, H6 XDI, IPDI, _H12 MDI, _NBDI , etc.) are preferably used from the viewpoint of weather resistance.

The polyol used for producing the urethane polyol is not particularly limited as long as it has a plurality of hydroxyl groups, and examples thereof include a low molecular weight polyol and a high molecular weight polyol. Examples of low molecular weight polyols include diols such as ethylene glycol, diethylene glycol, triethylene glycol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, and 1,6-hexanediol; glycerin and trimethylol. Triols such as propane and hexanetriol can be mentioned. Examples of high-molecular-weight polyols include polyether polyols such as polyoxyethylene glycol (PEG), polyoxypropylene glycol (PPG), and polyoxytetramethylene glycol (PTMG); polyethylene adipate (PEA) and polybutylene adipate (PBA). ), Condensed polyester polyols such as polyhexamethylene adipate (PHMA); lactone-based polyester polyols such as poly-ε-caprolactone (PCL); polycarbonate polyols such as polyhexamethylene carbonate; and acrylic polyols. Among the above-mentioned polyols, those having a weight average molecular weight of 50 to 2,000, particularly those having a weight average molecular weight of about 100 to 1,000 are preferably used. In addition, you may use these polyols by 1 type or a mixture of 2 or more types.

The urethane polyol is a polyol in which the polyisocyanate reacts with the polyol to form a urethane bond and has a hydroxyl group at the terminal. Here, the ratio of urethane bonds in the urethane polyol is preferably 0.1 mmol to 5 mmol in 1 g of the urethane polyol. The ratio of urethane bonds is related to the rigidity of the formed coating film, and if it is less than 0.1 mmol / g, the urethane concentration in the formed coating film is low, so that the scratch resistance may be insufficient. On the other hand, if it exceeds 5 mmol / g, the coating film becomes too hard, the followability to the deformation of the golf ball body is lowered, and cracks are likely to occur.

The weight average molecular weight of the urethane polyol is preferably 4,000 or more, more preferably 4,500 or more, preferably less than 10,000, and more preferably 9,000 or less. This is because if it is less than 4,000, it takes time to dry and workability and productivity are lowered. On the other hand, in the case of a urethane polyol having a high molecular weight of 10,000 or more, the hydroxyl value of the urethane polyol is relatively small, the reaction amount after coating is small, and the adhesion to the substrate is lowered. Further, when the weight average molecular weight is 9,000 or less, it is possible to form a dense coating film (or a clear paint layer) with little deterioration in adhesion even in a state of getting wet with water.

The hydroxyl value of the urethane polyol is preferably 15 mgKOH / g or more, more preferably 25 mgKOH / g or more, preferably 130 mgKOH / g or less, and more preferably 120 mgKOH / g or less. If it is less than 15 mgKOH / g, the amount of reaction with the curing agent is insufficient, so that it may be difficult to obtain the adhesion strength with the ball body. On the other hand, if it exceeds 130 mgKOH / g, it takes a long time to react with the curing agent, the drying time becomes long, the productivity decreases, and cracks are likely to occur at the time of impact.

The above urethane polyol can be obtained by reacting a polyol as a raw material with a polyisocyanate at a ratio such that the hydroxyl group of the polyol component becomes excessive with respect to the isocyanate group of the polyisocyanate component in terms of molar ratio. .. In the above reaction, a solvent or a catalyst known for the urethanization reaction (dibutyltin dilaurylate or the like) can be used. The urethane bond ratio can be adjusted by adjusting the molecular weight of the polyol as a raw material, the blending ratio of the polyol and the polyisocyanate, and the like.

The polyol component contained in the polyol composition is preferably the specific urethane polyol itself, but a polyol that is compatible with the urethane polyol and does not have a urethane bond may be contained in addition to the urethane polyol. In this case, the polyol having no urethane bond is not particularly limited, and the above-mentioned raw material polyol for urethane polyol synthesis can be used. When the polyol composition contains a polyol having no urethane bond, the content of the urethane polyol in the polyol component contained in the polyol composition is preferably 50% by mass or more, more preferably 80% by mass. It is preferable to make the above. This is because when the content of the urethane polyol in the polyol component is less than 50% by mass, the content of the urethane polyol is relatively small, so that the drying time becomes long.

Examples of the compound having a hydroxy group other than the terminal of the molecule include a modified polyrotaxane having a hydroxy group, a hydroxy group-modified vinyl chloride / vinyl acetate copolymer, and the like.

The modified polyrotaxane having a hydroxy group is arranged at both ends of the cyclodextrin, the linear molecule inserted into the cyclic structure of the cyclodextrin, and the linear molecule to prevent the cyclic molecule from being detached. It has a sequestering group. Polyrotaxane has viscous elasticity because cyclodextrin molecules that are skewered through linear molecules can move along the linear molecules (pulley effect), and even if tension is applied, this pulley effect. Since the tension can be uniformly dispersed, unlike the conventional crosslinked polymer, it has an excellent property that cracks and scratches are extremely unlikely to occur.

The cyclodextrin is a general term for oligosaccharides having a cyclic structure. Cyclodextrin is, for example, 6 to 8 D-glucopyranose residues linked in a cyclic manner by an α-1,4-glucosidic bond. Examples of cyclodextrin include α-cyclodextrin (glucose number: 6), β-cyclodextrin (glucose number: 7), γ-cyclodextrin (glucose number: 8), and α-cyclodextrin. preferable. The cyclodextrin may be used alone or in combination of two or more.

The linear molecule is not particularly limited as long as it is a linear molecule that holds the cyclic structure of cyclodextrin in a skewered manner so as to be slidable and rotatable. Examples of the linear molecule include polyalkylene, polyester, polyether, and polyacrylic, and among these, polyether is preferable, and polyethylene glycol is particularly preferable. Polyethylene glycol has less steric hindrance and can hold the cyclic structure of cyclodextrin in a skewered manner.

The weight average molecular weight of the linear molecule is preferably 5,000 or more, more preferably 6,000 or more, preferably 100,000 or less, and more preferably 80,000 or less.

The linear molecule preferably has functional groups at both ends thereof. By having a functional group, it can be easily reacted with the blocking group. Examples of the functional group include a hydroxy group, a carboxy group, an amino group, a thiol group and the like.

The blocking group is not particularly limited as long as it is arranged at both ends of the linear molecule and can prevent cyclodextrin from being eliminated from the linear molecule. Examples of the method for preventing desorption include a method of physically preventing desorption using a bulky sequestering group and a method of electrostatically preventing desorption using an ionic sequestering group. Examples of the bulky blocking group include cyclodextrin and adamantyl group. The number (retention amount) of cyclodextrin retained in the linear molecule is preferably 0.06 to 0.61 and more preferably 0.11 to 0.48, assuming that the maximum retention amount is 1. 24-0.41 is more preferable. If it is less than 0.06, the pulley effect may not be exhibited, and if it exceeds 0.61, cyclodextrin may be too densely arranged and the mobility of cyclodextrin may be reduced.

The polyrotaxane preferably has at least a part of the hydroxy group of cyclodextrin modified by a caprolactone chain. By caplactone denaturation, the steric hindrance between polyrotaxane and polyisocyanate is alleviated, and the reaction efficiency with polyisocyanate is enhanced.

As the modification, for example, the hydroxy group of cyclodextrin is treated with propylene oxide to form hydroxypropylation. Subsequently, ε-caprolactone is added to carry out ring-opening polymerization. Due to this modification, on the outside of the cyclic structure of cyclodextrin, the caprolactone chain- (CO (CH ₂ ) ₅ O) nH (n is a natural number of 1 to 100) has an -OC _{3H 6} -O- group. Join through. n represents the degree of polymerization, and is preferably a natural number of 1 to 100, more preferably 2 to 70, and even more preferably 3 to 40. A hydroxy group is formed at the other end of the caprolactone chain by ring-opening polymerization. The terminal hydroxy group of the caprolactone chain can react with the polyisocyanate.

The ratio of hydroxy groups modified by the caprolactone chain to the total hydroxy groups (100 mol%) of the cyclodextrin before modification is preferably 2 mol% or more, more preferably 5 mol% or more, and 10 mol% or more. Is even more preferable. When the ratio of the hydroxy group modified by the caprolactone chain is in the above range, the hydrophobicity of the polyrotaxane becomes high and the reactivity with the polyisocyanate becomes high.

The hydroxyl value of the polyrotaxane is preferably 10 mgKOH / g or more, more preferably 15 mgKOH / g or more, still more preferably 20 mgKOH / g or more, preferably 400 mgKOH / g or less, still more preferably 300 mgKOH / g or less, still more preferably. It is 220 mgKOH / g or less, particularly preferably 180 mgKOH / g or less. When the hydroxyl value of the polyrotaxane is within the above range, the reactivity with the polyisocyanate becomes high and the durability of the coating film becomes good.

The total molecular weight of the polyrotaxane is preferably 30,000 or more, more preferably 40,000 or more, further preferably 50,000 or more, preferably 3,000,000 or less, and more preferably 2 in terms of weight average molecular weight. , 500,000 or less, more preferably 2,000,000 or less. If the weight average molecular weight is 30,000 or more, the coating film has sufficient strength, and if it is 3,000,000 or less, the coating film has sufficient softness and the approach performance of the golf ball is improved. .. The weight average molecular weight of polyrotaxane is determined by, for example, by gel permeation chromatography (GPC), polystyrene as a standard substance, tetrahydrofuran as an eluent, and an organic solvent-based GPC column as a column (for example, "Shodex (registered trademark) manufactured by Showa Denko KK". ) KF series ", etc.) may be used for measurement.

Specific examples of the polyrotaxane modified with polycaprolactone include SELM superpolymers SH3400P, SH2400P, and SH1310P manufactured by Advanced Soft Materials.

The hydroxy group-modified vinyl chloride / vinyl acetate copolymer can adjust the adhesiveness while maintaining the scratch resistance of the coating film. The hydroxy group-modified vinyl chloride / vinyl acetate copolymer is, for example, a method for copolymerizing vinyl chloride, vinyl acetate and a monomer having a hydroxy group (for example, polyvinyl alcohol, hydroxyalkyl acrylate), vinyl chloride / vinyl acetate. It is obtained by a method of partially or completely saponifying the copolymer.

In the hydroxy group-modified vinyl chloride / vinyl acetate copolymer, the content of the vinyl chloride component is preferably 1% by mass or more, more preferably 20% by mass or more, further preferably 50% by mass or more, and 99% by mass or less. It is preferably 95% by mass or less, more preferably 95% by mass or less. Specific examples of the hydroxy group-modified vinyl chloride / vinyl acetate copolymer include Solvine (registered trademark) A, Solvine AL, and Solvine TA3 manufactured by Nisshin Chemical Industry Co., Ltd.

The polyol composition contains a urethane polyol containing a polyether diol having a number average molecular weight of 600 to 3000 as a constituent component (Aspect 1); a straight chain inserted into a cyclic structure of cyclodextrin and the cyclodextrin. It is a polyrotaxane having a shape molecule and a blocking group arranged at both ends of the linear molecule and preventing the elimination of the cyclodextrin, and at least a part of the hydroxy group of the cyclodextrin is -OC. An embodiment (aspect 2) containing a polyrotaxan modified with a caprolactone chain via a _{3H 6} -O- group is preferable.

(Polyisocyanate composition)
Examples of the polyisocyanate component of the polyisocyanate composition include compounds having at least two isocyanate groups. Examples of the polyisocyanate include 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, a mixture of 2,4-toluene diisocyanate and 2,6-toluene diisocyanate (TDI), and 4,4'-diphenylmethane diisocyanate (MDI). ), 1,5-naphthylene diisocyanate (NDI), 3,3'-bitrylene-4,4'-diisocyanate (TODI), xylylene diisocyanate (XDI), tetramethylxylylene diisocyanate (TMXDI), paraphenylenedi isocyanate ( Aromatic polyisocyanates such as PPDI); 4,4'-dicyclohexylmethane diisocyanate (H ₁₂ MDI), hydrogenated xylylene diisocyanate (H ₆ XDI), hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), norbornene diisocyanate ( Alicyclic polyisocyanates or aliphatic polyisocyanates such as NBDI); and derivatives of these polyisocyanates can be mentioned. In the present invention, two or more kinds of polyisocyanates may be used as the polyisocyanate.

Examples of the polyisocyanate derivative include an adduct-modified product obtained by reacting a diisocyanate with a polyhydric alcohol; an isocyanurate-modified product of diisocyanate; a burette-modified product, an alohanate-modified product, and the like, from which free diisocyanate is removed. Is more preferable.

In the colored coating film, the dye and / or the pigment is preferably 0.5 parts by mass or more, more preferably 0.6 parts by mass or more, and further preferably 0 by mass with respect to 100 parts by mass of the resin component constituting the coating film. It contains 7. by mass or more, preferably 3 parts by mass or less, more preferably 2.5 parts by mass or less, still more preferably 2.2 parts by mass or less, still more preferably 2.0 parts by mass or less. If the content is too high, the color of the golf ball becomes too deep and the color tone becomes dull, and if the content is too low, the desired color tone cannot be obtained.

The colored opaque coating may contain titanium oxide to enhance concealment. In this case, the content of titanium oxide is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, and preferably 10 parts by mass or less with respect to 100 parts by mass of the resin component constituting the coating film. , More preferably 8 parts by mass or less. By setting the content of titanium oxide to 0.5 parts by mass or more, concealing properties can be imparted to the coating film. Further, when the content of titanium oxide exceeds 10 parts by mass, the durability of the obtained coating film may decrease.

The coating film of the golf ball of the present invention preferably contains a filler. When a filler is contained, the appearance of the coating film may be matte.

As the filler, a filler generally used in paints can be used. Examples of the filler include silica (for example, fused silica (fused silica), dry silica (fused silica), precipitated silica, wet silica such as silica gel, colloidal silica), diatomaceous earth, zeolite, pearlite, mica, and glass. Examples thereof include wollastonite, potassium titanate, zonotrite, gypsum, aluminum borate, molybdenum disulfide, aramid, crystalline cellulose, alumina, carbon, metal particles, metal oxide particles and the like.

It is also preferable to use a porous filler as the filler. The porous filler has a large number of pores. The shape of the pores of the porous filler is not particularly limited. The pore diameter of the pores of the porous filler is not particularly limited, but is preferably 0.1 nm to 500 nm. The pore diameter of the porous filler differs depending on the type, but for example, the zeolite type has a pore size of 0.1 nm to 2 nm, and the diatomaceous earth has a pore size of about 300 nm.

Examples of the porous filler include diatomaceous earth, zeolite, and pearlite. Diatomaceous earth is a mud that is fossilized by the volume of diatom remains, which is a type of plankton, on the seabed or lake bottom. It is mainly composed of silica, and each particle has many fine mechanisms. Perlite is a porous body formed by high heat treatment of vitreous volcanic stones such as obsidian, pearlite, and pine fat ganiwa to evaporate the water contained in the volcanic stones. Zeolites are crystalline porous aluminosilicates. Examples of the structure of the zeolite include A type, ferrierite, ZSM-5, mordenite, beta, X type, Y type and the like. Zeolites also include porous silicalite. The porous filler may be used alone or in combination of two or more.

The volume average particle size of the filler is preferably 0.5 μm or more, more preferably 1.0 μm or more, further preferably 2.0 μm or more, preferably 30 μm or less, more preferably 20 μm or less, still more preferably 15 μm or less. Is. The volume particle size distribution is measured by laser diffraction, and the 50% integrated particle size (D50) in the volume particle size distribution is defined as the volume average particle size.

The content of the filler in the coating film is preferably 3 parts by mass or more, more preferably 5 parts by mass or more, still more preferably 8 parts by mass or more, and preferably 200 parts by mass or less with respect to 100 parts by mass of the resin component. , More preferably 150 parts by mass or less, still more preferably 120 parts by mass or less. When the content of the filler is 3 parts by mass or more, the appearance is matte, and when the content is 200 parts by mass or less, the appearance is good and the adhesion of dirt can be reduced.

The coating film may further contain additives that can be generally contained in golf paints, such as UV absorbers, antioxidants, light stabilizers, optical brighteners, and blocking inhibitors. UV absorbers and light stabilizers exemplified as those that can be blended in the intermediate layer and / cover can also be used in the coating film.

[core]
A known rubber composition (hereinafter, may be simply referred to as "rubber composition for core") can be used for the core of the golf ball of the present invention, and for example, a base rubber, a co-crosslinking agent, and a cross-linking initiator. The rubber composition containing the above can be heat-pressed and molded.

As the base rubber, it is particularly preferable to use high cis polybutadiene having a cis bond advantageous for repulsion of 40% by mass or more, preferably 70% by mass or more, and more preferably 90% by mass or more. As the co-crosslinking agent, α, β-unsaturated carboxylic acid having 3 to 8 carbon atoms or a metal salt thereof is preferable, and a metal salt of acrylic acid or a metal salt of methacrylic acid is more preferable. As the metal of the metal salt, zinc, magnesium, calcium, aluminum and sodium are preferable, and zinc is more preferable. The amount of the co-crosslinking agent used is preferably 20 parts by mass or more and 50 parts by mass or less with respect to 100 parts by mass of the base rubber. When an α, β-unsaturated carboxylic acid having 3 to 8 carbon atoms is used as the co-crosslinking agent, it is preferable to add a metal compound (for example, magnesium oxide). Organic peroxides are preferably used as the cross-linking initiator. Specifically, dicumyl peroxide, 1,1-bis (t-butylperoxy) -3,3,5-trimethylcyclohexane, 2,5-dimethyl-2,5-di (t-butylperoxy). Examples thereof include organic peroxides such as hexane and di-t-butyl peroxide, and among these, dicumyl peroxide is preferably used. The blending amount of the crosslinking initiator is preferably 0.2 parts by mass or more, more preferably 0.3 parts by mass or more, and more preferably 5 parts by mass or less, more preferably 5 parts by mass, based on 100 parts by mass of the base rubber. It is 3 parts by mass or less.

Further, the rubber composition for a core may further contain an organic sulfur compound. As the organic sulfur compound, diphenyl disulfides, thiophenols, and thionaphthols can be preferably used. The blending amount of the organic sulfur compound is preferably 0.1 part by mass or more, more preferably 0.3 part by mass or more, and more preferably 5.0 parts by mass or less with respect to 100 parts by mass of the base material rubber. It is preferably 3.0 parts by mass or less. The rubber composition for a core may further contain a carboxylic acid and / or a salt thereof. As the carboxylic acid and / or a salt thereof, a carboxylic acid having 1 to 30 carbon atoms and / or a salt thereof is preferable. As the carboxylic acid, either an aliphatic carboxylic acid or an aromatic carboxylic acid (benzoic acid or the like) can be used. The blending amount of the carboxylic acid and / or a salt thereof is 1 part by mass or more and 40 parts by mass or less with respect to 100 parts by mass of the base rubber.

[Manufacturing method of golf ball]
The core of a golf ball of the present invention is formed, for example, by heat-pressing a rubber composition for a core. The heating press molding conditions of the rubber composition for the core may be appropriately set according to the rubber composition, but are usually carried out at 130 ° C. to 200 ° C. and a pressure of 2.9 MPa to 11.8 MPa for 10 minutes to 60 minutes. .. For example, the rubber composition for a core is heated at 130 ° C. to 200 ° C. for 10 minutes to 60 minutes, or heated at 130 ° C. to 150 ° C. for 20 minutes to 40 minutes and then heated at 160 ° C. to 180 ° C. for 5 minutes. It is preferable to heat in two steps for 15 minutes.

Intermediate layer compositions and cover compositions are obtained, for example, by dry blending resin components, dyes and / or pigments, and optionally blended additives. Alternatively, the dry-blended mixture may be extruded and pelletized. For the dry blend, for example, it is preferable to use a mixer capable of blending pellet-shaped raw materials, and more preferably a tumbler type mixer is used. For extrusion, a known extruder such as a single-screw extruder, a twin-screw extruder, or a twin-screw single-screw extruder can be used.

The method for forming the intermediate layer is not particularly limited. Alternatively, a method of injecting a composition for an intermediate layer onto a spherical core to wrap the spherical core can be mentioned.

When the composition for an intermediate layer is injection-molded on a spherical core to form the intermediate layer, it is preferable to use a molding having a hemispherical cavity as the upper and lower molds for molding. In the molding of the intermediate layer by injection molding, the hold pin is projected, a spherical core is put in and held, and then the heat-melted composition for the middle layer is injected and cooled to form the middle layer. can.

When the intermediate layer is molded by a compression molding method, the half shell can be molded by either a compression molding method or an injection molding method, but the compression molding method is preferable. The conditions for compression molding the intermediate layer composition into a half shell are, for example, −20 ° C. or higher and + 70 ° C. with respect to the flow start temperature of the intermediate layer composition at a pressure of 1 MPa or more and 20 MPa or less. The following molding temperatures can be mentioned. By setting the molding conditions, a half shell having a uniform thickness can be molded. As a method of forming the intermediate layer using the half shell, for example, a method of covering a spherical core with two half shells and compression molding can be mentioned. The conditions for compression molding the half shell to form the intermediate layer are, for example, −20 ° C. or higher and + 70 ° C. with respect to the flow start temperature of the composition for the intermediate layer at a molding pressure of 0.5 MPa or more and 25 MPa or less. The following molding temperatures can be mentioned. By setting the molding conditions, an intermediate layer having a uniform thickness can be molded.

The molding temperature means the maximum temperature reached by the surface of the concave portion of the lower mold between the mold clamping and the mold opening. For the flow start temperature of the composition, a pellet-shaped thermoplastic resin composition was prepared using Shimadzu's "Flow Tester CFT-500" with a plunger area of 1 cm ² , DIE LENGTH: 1 mm, DIE DIA: 1 mm, and so on. It can be measured under the conditions of load: 588.399N, starting temperature: 30 ° C., and heating rate: 3 ° C./min.

The mode of molding the cover using the cover composition is not particularly limited, but is a mode of directly injection molding the cover composition onto the intermediate layer, or molding a hollow shell-shaped shell from the cover composition. An embodiment in which a sphere on which an intermediate layer is formed is covered with a plurality of shells and compression-molded (preferably, a hollow shell-shaped half shell is formed from a cover composition, and the sphere on which the intermediate layer is formed is formed into two halves. A method of covering with a shell and compression molding) can be mentioned. It is preferable that the golf ball body on which the cover is formed is taken out from the mold and, if necessary, surface-treated such as deburring, cleaning, and sandblasting. Also, if desired, a mark can be formed.

In the present invention, for example, a hollow shell-shaped first shell having a first color and a hollow shell-shaped second shell having a second color are produced, and a sphere having an intermediate layer formed thereof is used as a plurality of first shells. By covering with a second shell and compression molding, a first region and a second region are formed on the surface of the golf ball. Further, a hollow shell-shaped half shell having a first color and a hollow shell-shaped half shell having a second color are molded, and a sphere on which an intermediate layer is formed is covered with these two half shells and compression molded. By doing so, a first region having a hemispherical first color and a second region having a hemispherical second color are formed on the surface of the golf ball.

It is preferable that dimples are formed on the cover of the golf ball of the present invention. The total number of dimples formed on the cover is preferably 200 or more and 500 or less. If the total number of dimples is less than 200, it is difficult to obtain the effect of dimples. Further, when the total number of dimples exceeds 500, the size of each dimple becomes small, and it is difficult to obtain the effect of the dimples. The shape of the dimples to be formed (planar shape) is not particularly limited, and a circle; a polygon such as a substantially triangle, a substantially quadrangle, a substantially pentagon, and a substantially hexagon; and other indefinite shapes; are used alone. Alternatively, two or more kinds may be used in combination.

It is preferable to remove the golf ball from which the cover is formed from the mold and perform surface treatment such as deburring, cleaning, and sandblasting as necessary. Further, if desired, a coating film or a mark can be formed.

The coating film of the golf ball of the present invention can be formed by applying a paint to the surface of the golf ball body. The method of applying the paint is not particularly limited, and a known method can be adopted, and examples thereof include spray painting and electrostatic coating.

When the first region having the first color or the second region having the second color is formed by the colored coating film, it is formed, for example, by applying a paint to a desired shape of the first region or the second region. be able to.

When spray painting using a two-component curable urethane paint as the paint, the polyisocyanate composition and the polyol composition are supplied by their respective pumps and continuously mixed by a line mixer arranged immediately before the air gun. , The obtained mixture may be spray-painted, or the polyol and the polyisocyanate may be spray-painted separately by using an air spray system provided with a mixing ratio control mechanism. The coating may be applied by spraying once or may be applied multiple times.

The paint applied to the golf ball body can form a coating film by, for example, drying at a temperature of 30 ° C. to 70 ° C. for 1 hour to 24 hours.

[Golf ball structure]
The structure of the golf ball of the present invention is not particularly limited as long as it has a core and a cover arranged outside the core. In a preferred embodiment, the golf ball of the present invention has at least one intermediate layer between the core and the cover. The structure of the golf ball includes, for example, a two-piece golf ball having a spherical core and a cover covering the spherical core, a single intermediate layer covering the spherical core and the spherical core, and covering the intermediate layer. A three-piece golf ball having a cover; a multi-piece golf ball having a spherical core, two or more intermediate layers covering the spherical core, and a cover covering the intermediate layer; and the like.

When there are multiple intermediate layers, the color tone of the outermost layer of the intermediate layer is measured.

The core of the golf ball of the present invention is preferably spherical. The diameter of the spherical core is preferably 34.8 mm or more, more preferably 36.8 mm or more, further preferably 38.8 mm or more, preferably 42.2 mm or less, more preferably 41.8 mm or less, still more preferably 41. It is .2 mm or less, and most preferably 40.8 mm or less. When the diameter of the spherical core is 34.8 mm or more, the thickness of the cover does not become too thick, and the resilience becomes better. On the other hand, when the diameter of the spherical core is 42.2 mm or less, the cover does not become too thin and the function of the cover is more exhibited.

The thickness of the intermediate layer is preferably 0.8 mm or more, more preferably 0.9 mm or more, further preferably 1.0 mm or more, preferably 2.2 mm or less, more preferably 2.0 mm or less, still more preferably. It is 1.8 mm or less. If the thickness of the intermediate layer is 0.8 mm or more, the molding of the intermediate layer becomes easier, and if it is 2.2 mm or less, the diameter of the core can be relatively increased, so that the repulsion performance of the golf ball is improved. When there are a plurality of intermediate layers, it is preferable that the total thickness of the plurality of intermediate layers is within the above range.

The cover of the golf ball of the present invention is preferably a single layer. The thickness of the cover is preferably 0.3 mm or more, more preferably 0.4 mm or more, further preferably 0.5 mm or more, preferably 2.0 mm or less, more preferably 1.5 mm or less, still more preferably 1. It is 0.0 mm or less. When the thickness of the cover is 0.3 mm or more, the molding of the cover becomes easier, and when the thickness is 2.0 mm or less, the diameter of the core can be relatively increased, so that the repulsion performance of the golf ball is improved.

The film thickness of the coating film is not particularly limited, but is preferably 5 μm or more, more preferably 7 μm or more, more preferably 50 μm or less, still more preferably 40 μm or less, still more preferably 30 μm or less. This is because if the film thickness is less than 5 μm, the coating film is likely to wear away due to continuous use, and if the film thickness exceeds 50 μm, the effect of dimples is reduced and the flight performance of the golf ball is deteriorated.

The diameter of the golf ball of the present invention is preferably 40 mm to 45 mm. A diameter of 42.67 mm or more is particularly preferred from the perspective of meeting the standards of the United States Golf Association (USGA). From the viewpoint of suppressing air resistance, the diameter is more preferably 44 mm or less, and particularly preferably 42.80 mm or less. The mass of the golf ball is preferably 40 g or more and 50 g or less. From the viewpoint of obtaining a large inertia, the mass is more preferably 44 g or more, and particularly preferably 45.00 g or more. From the viewpoint that the USGA standard is satisfied, the mass is particularly preferably 45.93 g or less.

FIG. 5 is a partially cutaway sectional view showing a golf ball 1 according to an embodiment of the present invention. The golf ball 1 has a spherical core 2, an intermediate layer 3 that covers the spherical core, and a cover 4 that covers the intermediate layer. A large number of dimples 31 are formed on the surface of this cover. The portion of the surface of the golf ball other than the dimple 31 is the land 32. This golf ball has a paint layer 5 on the outside of the cover.

Hereinafter, the present invention will be described in detail by way of examples, but the present invention is not limited to the following examples, and changes and embodiments within the scope not deviating from the gist of the present invention are all of the present invention. Included within range.

[Evaluation method]
(1) Color tone The color tone of the intermediate layer and the surface of the golf ball was measured using a color difference meter (“CM-350d” manufactured by Konica Minolta Co., Ltd.). The color tone of the golf ball was measured with a coating film formed on the golf ball body.
Measurement conditions Measurement wavelength range: 360 nm to 740 nm
Measurement area (diameter): 8 mmφ
Measurement time: 1 second

(2) Ease of finding on the rough With each golf ball submerged in the rough (turf length 5 to 10 cm), check each golf ball at a distance of 1 m to 10 m from the subject every 1 m, and check the color of the ball. The longest distance that can answer the combination correctly was calculated. Evaluated by 20 subjects, the average distance was calculated.

(3) Discomfort at the time of shot Place the golf ball so that the boundary between the hemispherical first region and the hemispherical second region can be seen for 20 subjects, and have them address with a driver to make a shot. I took a total of whether or not I answered that there was no sense of discomfort.
◎: 17 to 20 people answered that they did not feel uncomfortable.
〇: 13 to 16 responded that there was no discomfort.
Δ: 9 to 12 responded that there was no discomfort.
×: 8 or less responded that there was no discomfort.

[Making golf balls]
(1) Preparation of core The rubber composition having the composition shown in Table 1 is kneaded by a kneading roll and heated and pressed at 170 ° C. for 20 minutes in an upper and lower mold having a hemispherical cavity to obtain a spherical core having a diameter of 39.7 mm. Obtained. Barium sulfate was adjusted so that the mass of the obtained golf ball was 45.3 g.

The raw materials used in Table 1 are as follows.
Polybutadiene rubber: JSR's high cis polybutadiene "BR730" (cis-1,4-bond content = 96% by mass, 1,2-vinyl bond content = 1.3% by mass, Mooney viscosity (ML _{1 + 4)} (100 ° C.)) = 55, molecular weight distribution (Mw / Mn) = 3)
Zinc Acrylate: "ZNDA-90S" manufactured by Nikko Techno Fine Chemical Co., Ltd.
Zinc oxide: "Ginmine R" manufactured by Toho Zinc Co., Ltd.
Barium Sulfate: "Barium Sulfate BD" manufactured by Sakai Chemical Industry Co., Ltd.
PBDS: Kawaguchi Chemical Industry Co., Ltd. bis (pentabromodiphenyl) disulfide disulfide Dicumyl peroxide: NOF Corporation, "Park Mill (registered trademark) D"

(2) Molding of Intermediate Layer The compounding materials shown in Table 2 were mixed by a twin-screw kneading type extruder to prepare a pellet-shaped resin composition for an intermediate layer. The extrusion conditions were a screw diameter of 45 mm, a screw rotation speed of 200 rpm, and a screw L / D = 35, and the compound was heated to 160 to 230 ° C. at the position of the die of the extruder. The obtained resin composition for an intermediate layer was injection-molded on the spherical core obtained as described above to form an intermediate layer having a thickness of 1 mm.

Himilan 1605: Sodium ion-neutralized ethylene-methacrylic acid copolymer ionomer resin manufactured by Mitsui Dau Polychemical Co., Ltd. Himilan AM7329: Zinc ion-neutralized ethylene-methacrylic acid copolymer system manufactured by Mitsui Dau Polychemical Co., Ltd. Ionomer resin Titanium oxide: Ishihara "A220" manufactured by Sangyo Co., Ltd.
FX305: Lemon Yellow manufactured by Shinroihi
GPX-17: Deigro Saturn Yellow GPL-15: Deigro Blaze Orange

(3) Cover molding The materials shown in Table 3 were dry-blended and mixed with a twin-screw kneading extruder to obtain a pellet-shaped cover (half-shell) composition. Extrusion was performed with a screw diameter of 45 mm, a screw rotation speed of 200 rpm, and a screw L / D = 35. The formulation was heated to 150-230 ° C. at the position of the die of the extruder.

In the compression molding of the half shell, the obtained pellet-shaped resin composition for a cover was put into each recess of the lower mold of the half shell molding die and pressed to form the half shell. The compression molding was performed under the conditions of a molding temperature of 170 ° C., a molding time of 5 minutes, and a molding pressure of 2.94 MPa.
The spherical core forming the intermediate layer obtained above was concentrically covered with two half shells A and half shells B having different color tones, and a cover was formed by compression molding. The compression molding was performed under the conditions of a molding temperature of 150 ° C., a molding time of 2 minutes, and a molding pressure of 9.8 MPa. The thickness of the cover was 0.5 mm.

The raw materials used in Table 3 are as follows.
Urethane resin: Elastolan (registered trademark) NY80A: Made by BASF Japan, polyurethane elastomer (polyol component; polytetramethylene ether glycol, polyisocyanate component; dicyclohexylmethane-4,4'-diisocyanate, chain extender; 1,4- Butanediol) (Shore A hardness 80)
JF-90: Johoku Chemical Industry Co., Ltd., light stabilizer Titanium oxide: Ishihara Sangyo Co., Ltd., "A220"
Epocolor FP3000: Made by UKSEUNG CHEMICAL CO., LTD. (Fluorescent pigment in which a fluorescent dye is dispersed and fixed in a benzoguanamine resin (condensation of benzoguanamine and formaldehyde))
FX305: Lemon Yellow manufactured by Shinroihi
FX-327: Magenta manufactured by Shinroihi
GPX-17: Saturn Yellow GPL-15 manufactured by Daeguro: Blaze Orange ZQ-14 manufactured by Dagro (fluorescent pigment in which fluorescent dye is dispersed and fixed in polyester resin) Fire Orange ZQ-17: Made by Daeguro (fluorescent pigment in which fluorescent dye is dispersed and fixed in polyester resin) Saturn Yellow ZQ-18: Made by Dagro (fluorescent pigment in which fluorescent dye is dispersed and fixed in polyester resin) Signal Green FP113: UKSEUNG Made by CHEMICAL CO., LTD. Red (RED)
FP1050: UKSEUNG CHEMICAL CO., LTD. Blue (BLUE)

(4) Preparation of paint composition [Polyol composition No. 1 (urethane polyol)]
Polytetramethylene ether glycol (PTMG, number average molecular weight 650) and trimethylolpropane (TMP) were dissolved in a mixed solvent (toluene / methylethylketone, mass ratio: 15/85). The molar ratio (PTMG: TMP) was 1.8: 1.0. To this solution, 0.1% by mass of dibutyltin dilaurate was added as a catalyst to the total amount of the main agent. Isophorone diisocyanate (IPDI) was added dropwise while keeping this polyol solution at 80 ° C. The molar ratio (NCO / OH) of this mixed solution was 0.6. After the dropping, stirring was continued until the isocyanate component in the mixed solution disappeared, and then the mixture was cooled at room temperature to obtain a polyol composition No. 1 containing a urethane polyol. 1 was obtained as a main agent. Polyol Composition No. The solid content of 1 was 30% by mass, the content of PTMG was 67% by mass, the hydroxyl value of the solid content was 67.4 mgKOH / g, and the weight average molecular weight of the urethane polyol was 4867. When a filler was added, it was added to the polyol composition. The blending amount was 45 parts by mass with respect to 100 parts by mass of the polyol composition constituting the coating film.

[Polyisocyanate composition No. 1]
30 parts by mass of isocyanurate modified product of hesamethylene diisocyanate (trade name "Duranate TKA-100" of Asahi Kasei Chemicals Co., Ltd., NCO content: 21.7% by mass), 30 parts by mass of hexamethylene diisocyanate burette modified product (Asahi Kasei) Chemicals trade name "Duranate 21S-75E", NCO content: 15.5% by mass), and 40 parts by mass of isophorone diisocyanate isocyanurate modified (BAYER trade name "Death Module Z4470", NCO content : 11.9% by mass) was mixed. To this mixture, methyl ethyl ketone, n-butyl acetate and toluene were added as solvents and mixed to obtain Polyisocyanate Composition No. 1 was obtained as a curing agent. The concentration of the polyisocyanate component in this composition was 60% by mass.

The polyol composition and the polyisocyanate composition were mixed at the blending ratios shown in Table 4 to prepare a coating composition. After sandblasting and marking the surface of the golf ball body obtained above, the paint was applied with a spray gun, and the paint was dried in an oven at 40 ° C. for 24 hours to have a diameter of 42.7 mm and a mass of 45. I got a 3g golf ball.

Silica: Evonik CARPLEX FPS-1 (wet silica, volume average particle size: 7.0 μm)

The painting was performed by placing the golf ball main body on a rotating body equipped with a prong, rotating the rotating body at 300 rpm, blowing an air gun from the golf ball main body and moving it in the vertical direction at a distance (7 cm). The interval for each recoating was 1.0 second. The spraying conditions of the air gun are: recoating; 2 times, spraying air pressure; 0.15 MPa, pressure feeding tank air pressure; 0.10 MPa, 1 time coating time; 1 second, atmospheric temperature; 20 ° C to 27 ° C, atmospheric humidity; It was painted under the condition of 65% or less. The results of evaluation of the obtained golf balls are also shown in Table 5.

From Table 5, it is a golf ball having a core and a cover arranged outside the core, and the surface of the golf ball has a first region of a first color and a second region of a second color. The hue of the first color is H1 represented by using the H value according to the HSL color space, and the hue of the second color is H2 represented by using the H value according to the HSL color space. A golf ball that satisfies a specific relationship with H2 has high visibility and a small sense of discomfort at the time of a shot.

1: Golf ball 2: Spherical core 3: Intermediate layer 4: Cover 5: Coating film, 31: Dimple, 32: Land

Claims (11)

A golf ball having a core and a cover arranged on the outside of the core.
The surface of the golf ball has a first region of the first color and a second region of the second color.
The hue of the first color is H1 represented by using the H value according to the HSL color space.
The hue of the second color is H2 represented by using the H value according to the HSL color space.
A golf ball characterized in that the H1 and the H2 satisfy the following mathematical formula (1) or mathematical formula (2).
0 ≦ ｜ H1-H2 ｜ ≦ 60 (1)
300 ≦ ｜ H1-H2 ｜ ≦ 360 (2) It has at least one intermediate layer between the core and the cover.
The hue of the outermost layer of the intermediate layer is H0 represented by using the H value according to the HSL color space.
The golf ball according to claim 1, wherein one of | H0-H1 | and | H0-H2 | is less than 10 and the other is 10 or more. The saturation of the first color in the first region is S1 represented by the S value in the HSL color space.
The luminance of the first color in the first region is L1 represented by the L value in the HSL color space.
The golf ball according to claim 1 or 2, wherein S1 is 40 or more and 100 or less, and L1 is 30 or more and 100 or less. The saturation of the second color in the second region is S2 represented by the S value in the HSL color space.
The luminance of the second color in the second region is L2 represented by the L value in the HSL color space.
The golf ball according to any one of claims 1 to 3, wherein S2 is 40 or more and 100 or less, and L2 is 30 or more and 100 or less. The first region and the second region are regions surrounded by two boundary lines connecting the first pole and the second pole of the golf ball surface, respectively, and are continuous from the first pole to the second pole. The golf ball according to any one of claims 1 to 4, which is the area of the golf ball. The golf ball according to any one of claims 1 to 5, wherein the first region and the second region are hemispherical, respectively. The golf ball according to claim 1 to 6, which has a coating film covering the cover, and the coating film contains a resin component and a filler. The golf ball according to any one of claims 1 to 6, which has a coating film covering the cover, and the coating film is a clear coating film. The golf ball according to any one of claims 1 to 8, wherein the first region and the second region are each formed of a colored cover. The golf ball according to any one of claims 1 to 8, wherein the first region and the second region are each formed of a colored coating film. Claims 1-8, wherein one of the first region and the second region is formed by a colored cover, and the other of the first region and the second region is formed by a colored coating film. The golf ball described in any one of the items.

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