JP2001120687A - Golf ball - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a one-piece golf ball, the color tone of which is vivid, that does not give a feeling of incongrity when one strikes a ball, is weather resistant and yellow. SOLUTION: A one-piece golf ball, the color tone of which is adjusted to meet the L value of L>=85 and the b value of b=90-110 under the Lab system.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color golf ball, and more particularly to a yellow one-piece golf ball having a bright appearance and excellent weather resistance.

[0002]

2. Description of the Related Art A majority of one-piece golf balls used in a driving range are white balls, but some are colored one-piece golf balls, for example, yellow, which are made by paying attention to the eccentricity of the appearance. Colored one-piece golf balls have also begun to be used. Since the golf practice range is used day and night, and in many cases, the ball is hit from light-shielded indoors to bright outdoors, the yellow one-piece golf ball must be bright and clearly yellow. Is desired.

[0003] Pigments are used for coloring golf balls. Conventional one-piece colored golf balls are roughly classified into a "paint type" in which a paint containing a pigment is painted on the surface of a golf ball, and a golf ball body. There is a "kneading type" in which a pigment is kneaded into the rubber composition.

[0004] The former coating die is a problem that cannot be avoided because it is repeatedly and repeatedly exposed to a hit ball at a driving range. When the ball is hit, the painted portion is peeled off and the color of the base is exposed. However, since the base color and the paint color are not the same color, the peeled portion is conspicuous and the appearance is greatly impaired. Therefore, Japanese Patent Application Laid-Open No. 5-261166 attempts to make up for the above-mentioned drawbacks by bringing the color of the paint closer to the color of the base. That is, a contrivance has been made to make the color of the base (rubber composition) close to the color of the paint. On the other hand, in order to develop vivid yellow, it is necessary to set the b value (value indicating yellow tint) in the Lab color difference display to 90 or more.
It is necessary to use a paint containing a large amount of pigment, and there is a problem that the strength of the coating film itself and the adhesion to the base are reduced.

The kneading type is disclosed in Japanese Patent Application Laid-Open No. 7-5140.
No. 3 discloses a white one-piece golf ball. However, with regard to color golf balls, particularly golf balls that exhibit yellow color, no attention is paid to maintaining the beauty of appearance such as brightness and vividness of yellowness only by the color of the rubber composition.

[0006] A color golf ball is also disclosed in Japanese Patent Application Laid-Open No. H10-155937, but is directed to a two-piece color golf ball obtained by coloring a cover or painting a surface. -30
Since it is +30, there is an advantage that the ball looks white when viewed from a distance during play, but it is necessary to add another device in order to recognize the ball as a colored ball in any situation.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and has as its object to peel off a coating film in the above-mentioned coating mold and to provide a rubber composition as a base in that case. It is a one-piece golf ball of a pigment-impregnated type that does not need to stick to the problem such as the difference between the color of the surface coating film and the color of the surface coating film, saves the trouble of painting, and makes it relatively easy to adjust the color. It is another object of the present invention to provide a yellow one-piece golf ball having excellent resistance to ultraviolet rays, rain, snow, and the like, that is, excellent weather resistance.

[0008]

A golf ball according to the present invention is a one-piece golf ball having a color tone of La.
The gist is that the L value and the b value satisfy the following when expressed by the b method. L ≧ 85 b = 90-110 The a value and the b value when represented by the Lab method are:
It is preferable to satisfy the following relationship. 90 ≦ (a ² + b ² ) ^1/2 ≦ 115 Further, the value a is preferably in the range of −30 to +30.

Further, the one-piece golf ball includes
It is desirable that a clear coating film is formed.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The one-piece golf ball of the present invention is obtained by appropriately combining a rubber composition and a pigment so that the L value and the b value when the color tone is represented by a Lab system satisfy the following. A vivid yellow color tone can be obtained without coloring the ball surface. L ≧ 85 b = 90-110

Here, the Lab display of the color tone is based on JIS-
The Lab color difference measured in accordance with Z-8701 or JIS-Z-8728 is converted as follows using the tristimulus values X, Y, and Z. In addition, the color difference meter of CR-221 made by Minolta which employs a stimulus value direct reading method is used for the measurement. L = 116 (Y / Y _N ) ^1/3 −16 a = 500 [(X / X _N ) ^1/3 − (Y / Y _N ) ^1/3 ] b = 200 [(Y / Y _N ) ^{1 / 3} − (Z / Z _N ) ^1/3 ] X _N , Y _N , Z _N : tristimulus values in the X, Y, Z system of the perfect diffuse reflection surface

The L value is an index of lightness, and the larger the L value, the brighter. The a-value and the b-value serve as hue indices. When the a-value increases, the color becomes red, and when the a-value decreases, the color becomes green. When the b value increases, the color becomes yellow, and when the b value decreases, the color becomes blue.

In the present invention, the L value is set to 85 or more in order to give a dark and dull impression when the L value is less than 85. The larger the L value, the better, but the larger the L value, the higher the whiteness. Therefore, the L value is preferably 95 or less, more preferably 90 or less.

In the present invention, the b value is set to 90 to 11 as described above.
Set to 0. If the b value is smaller than 90, the evaluation as a ball having a yellow tint cannot be obtained, and the b value is 1
If it is larger than 10, the yellowness is too deep, giving a heavy feeling when hitting a ball. Even if the b value is 110 or less, a sufficiently yellowish color is exhibited. The b value is preferably 93 to 108. In order to increase the b value to 90 or more, it is necessary to contain a large amount of pigment. In the case of the above-mentioned "paint type" ball having a colored paint film, the strength and adhesion of the paint film are reduced. It has been regarded as a means that cannot be adopted. However, in the one-piece golf ball of the present invention, there is no need to make a problem because the pigment is contained in the golf ball body.

In the present invention, it is preferable that the value a is -30 to +30. If the value a is larger than the specified range, the ball becomes reddish. If the value a becomes smaller, the ball becomes greenish. In any case, the ball gives a dark or heavy impression. The value a is more preferably -15 to +1
5, more preferably −13 to +13, and in order to obtain a clear yellow excellent appearance, it is desirable that the value a is particularly negative. When adjusting the yellow tint, not only a yellow pigment but also a red or orange pigment may be used. In such a case, the a value is adjusted so as to be within the above range.

Further, in the present invention, 90 ≦ (a ² + b ² )
Preferably, ^1/2 ≦ 115. The value of (a ² + b ² ) ^1/2 is an index representing vividness. (A ² + b ² ) ^1/2 is 9
If it is smaller than 0, the color will be recognized lightly,
Or it is difficult to recognize the ball on cloudy, rainy or snowy days. Further, when (a ² + b ² ) ^1/2 is larger than 115, the color is felt deep, and the sense of weight at the time of hitting ball is increased. (A ² + b ² ) ^1/2 is more preferably from 90 to 114, and even more preferably from 93 to 1
09 is preferable, and 94 to 102 is particularly preferable.

The above L value is 85 or more and (a ² + b ² )
^{When 1/2} is 90 to 115, the color becomes very bright and vivid, so that the feeling of exhilaration at the time of hitting, the vividness of the ballistic trajectory, the discrimination of the falling ball, and the like are excellent.

The golf ball of the present invention is produced by vulcanizing a rubber composition containing a base rubber and a co-crosslinking agent.
The rubber composition used in the present invention is obtained by adding α, β- to base rubber conventionally used in the production of one-piece golf balls.
Those containing an unsaturated carboxylic acid, a metal salt thereof, an organic peroxide or the like are preferred. As the base rubber, butadiene rubber (BR), ethylene propylene diene 3
One or two or more of an original copolymer (EPDM), isoprene rubber (IR), butyl rubber (IIR), natural rubber (NR), acrylonitrile / butadiene rubber (NBR), styrene / butadiene rubber (SBR) and the like are used. Can be Of these, a rubber containing butadiene as a main component is desirable, and specifically, 50% by weight of the base rubber used.
The above is preferably butadiene rubber. As the butadiene rubber, it is preferable to use a high cis polybutadiene having a cis-1,4 bond content of 90% or more. In the examples of the present invention, high cis polybutadiene rubber BR-11 manufactured by Nippon Synthetic Rubber Co., Ltd. was used as the base rubber.

As the pigments, inorganic pigments such as red iron (Fe ₂ O ₃ ), red lead (Pb ₃ O ₄ ), molybdenum red,
Red pigments such as cadmium red; titanium yellow (20
TiO ₂ —NiO—Sb ₂ O ₃ ), litharge (PbO),
Yellow lead (PbCrO ₄ ), yellow iron oxide (FeO (O
H)) and yellow pigments such as cadmium yellow. As the organic pigment, azo pigments, phthalocyanine pigments, perylene pigments and the like can be used, but pigments having good heat resistance and weather resistance are preferably used, and azo pigments are particularly preferably used. Examples of the azo pigment include Pigment Yellow-1, Pigment Yellow-12, Pigment Red-3, Pigment Red-57, and Pigment Orange-13.

Further, it is desirable that a clear coating film is formed on the surface of the ball. Scratches on the surface generated when hit with a golf club, preventing wear and improving the durability of the surface without impairing the color of the rubber composition,
It is applied for the purpose of creating a glossy feeling and a high-grade feeling.

[0021]

EXAMPLES In Examples and Comparative Examples, after mixing the rubbers and the like shown in Table 1 with the pigments shown in Table 2 and kneading them, vulcanization molding was performed at 160 ° C. for 30 minutes. A yellow one-piece golf ball was created.

As the pigments, LB305 (yellow) and LB200 (orange) manufactured by Sumika Color Co., Ltd., organic pigments, and BX LB (red) manufactured by Resino Color Industrial Co., Ltd. were used in the composition shown in Table 2. A clear painting was performed to obtain a yellow golf ball. For clear coating, as a coating film forming element,
Those containing urethane resin and acrylic resin were used. Further, an ultraviolet absorber, an antioxidant, a light stabilizer and the like for preventing the deterioration of the clear coat and the ball body from being deteriorated are appropriately blended. In the present invention, 0.5 parts by mass of the ultraviolet absorbent is included with respect to 100 parts by mass of the urethane resin.

[0023]

[Table 1]

[0024]

[Table 2]

Table 3 shows the measurement results of the color tones of the color balls and the results of the appearance evaluation of the colors.
Shown in Table 4 shows the results of measuring the degree of discoloration of the weather resistance with a color difference meter and the results of visually evaluating the degree of discoloration.
Shown in The appearance evaluation and the weather resistance evaluation of the color were performed based on the following methods.

[Evaluation Method] Color Appearance Evaluation A feeling test was performed on the degree of yellowness of ten golfers at a golf driving range. The evaluation was “◎” when the ball felt very suitable as a yellow ball, “○” when felt suitable as a yellow ball, and felt that the ball was not suitable as a yellow ball The case was marked "x".

Evaluation of weather resistance Using a sunshine super long life weather meter (WEL-SUN-HC / B type) manufactured by Suga Test Instruments Co., Ltd. under the conditions of a tank temperature of 63 ° C., a humidity of 50%, and a rainfall of 12 minutes in 60 minutes. For 120 hours, and the color tone before and after the irradiation was measured to examine the degree of discoloration. That is, the L value, a value, and b value are measured by a color difference meter before being put into the apparatus, and the same measurement point of each ball is measured again after processing for 120 hours, and the difference (ΔL, Δa, Δb) of each value is measured. Substituted in the following formula and calculated value Δ
E was evaluated according to the size of E. The greater the ΔE value, the greater the degree of discoloration. ΔE = [(ΔL) ² + (Δa) ² + (Δb) ² ] ^1/2 Table 4 shows the numerical value of each example when Comparative Example 1 having the largest value is set to 100. The visual evaluation was expressed in three stages: "◎" when the degree of discoloration was minimal, "○" when the degree of discoloration was small, and "X" when the degree of discoloration was large.

[0028]

[Table 3]

[0029]

[Table 4]

From Tables 3 and 4, Examples 1 to 3 satisfy all of the constituent requirements of the present invention, and have excellent color appearance and weather resistance.

On the other hand, in Comparative Example 1, in the appearance evaluation of the colors shown in Table 3, the b value was lower than the specified range of the present invention, the color tone was slightly reddish, and the ball was not recognized as yellow. Not only, (a ² + b ² ) ^1/2
Also fell outside the specified range and became dark and dull. In Comparative Example 2, the L value was below the specified range of the present invention, and (a)
² + b ²⁾ for ^1/2 is also less than the specified range, it has become possible to give a dull dark impression. Further, in Comparative Example 3, the b value and (a ² + b ² ) ^1/2 were less than the specified range of the present invention, so that the yellow ball was light and it was difficult to obtain recognition as a yellow ball. Further, in Comparative Example 4, the b value was more than the specified range of the present invention, and the yellowness was too strong to give a heavy impression when hitting a ball.

It should be noted that, unlike a normal round ball, a one-piece golf ball at a practice range, after being hit,
It is often left for a long time under natural conditions such as rainfall and sunlight. Therefore, the one-piece golf ball needs to have resistance to discoloration caused by such natural conditions, that is, weather resistance.
In Nos. 2 and 4, the ΔE value indicating the degree of discoloration was large, and the weather resistance was poor.

[0033]

The present invention is configured as described above. By adjusting the color tone of a golf ball within the specified range of the present invention, the golf ball has a vivid color tone but does not give a sense of incongruity when hitting a ball. It was possible to provide a yellow one-piece golf ball having excellent resistance to ultraviolet rays and the like, that is, excellent weather resistance.

Claims (4)

[Claims] 1. A one-piece golf ball, wherein when the color tone is represented by a Lab method, the L value and the b value satisfy the following. L ≧ 85 b = 90-110 2. The golf ball according to claim 1, wherein the a value and the b value in the Lab system satisfy the following relationship. 90 ≦ (a ² + b ² ) ^1/2 ≦ 115 3. The golf ball according to claim 1, wherein the a value is in a range of −30 to +30. 4. The golf ball according to claim 1, further comprising a clear coating film.