JPH11226152A - Golf ball covering material and golf ball using it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve weatherability and whiteness by containing stilbene bisbenzoxazole derivative expressed by a formula as an optical whitening agent. SOLUTION: This golf ball covering material is formed by using a whitening material such as titanium dioxide as a whitening pigment. The stilbene bisbenzoxazole derivative expressed by the formula (R expresses H or CH3 ) is mixed as an optical whitening agent. The mixing rate of the stilbene bisbenzoxazole derivative is set to 0.01-0.03 pts.wt. in relation to the base resin 100 pts.wt. such as ionomer resin constituting a covering material. For example, 4-(2-benzoxazolyl)-4'-(5-methyl-2-benzoxazolyl) stilbene is used as the stilbene bisbenzoxazole derivative. By this constitution, the whiteness degree can be heightened, the yellowness degree be lowered, and weatherability is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a golf ball cover material having excellent weather resistance and whiteness, and a golf ball using the same.

[0002]

2. Description of the Related Art Conventionally, a primer paint is applied to the surface of a golf ball cover in which a core is covered with a cover, and an enamel paint having a white pigment such as titanium dioxide is applied thereon. The surface finish of golf balls is performed by applying transparent clear paint. Then, in order to make the golf ball look whiter, any of these paints contains a fluorescent whitening agent.

[0003] However, when the paint surface of the golf ball is finished in this manner, there is a problem that the cover surface is exposed due to paint peeling or the like, and the white appearance is impaired. Therefore, attempts have been made to include a fluorescent whitening agent together with a white pigment in the cover material constituting the cover, but the conventional fluorescent whitening agent has the disadvantage that the weather resistance of the cover material is poor and the whiteness is poor. Was.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a cover material for a golf ball which contains a fluorescent whitening agent and is excellent in weather resistance and whiteness, and a golf ball using the same. It is in.

[0005]

The golf ball cover material of the present invention is characterized by containing a stilbenebisbenzoxazole derivative having the following formula as a fluorescent whitening agent.

[0006]

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Further, the golf ball of the present invention is characterized in that the cover is made of this cover material. As described above, since the stilbenebisbenzoxazole derivative is contained in the cover material as a fluorescent whitening agent, the above object can be achieved. Also, since the cover material contains a fluorescent whitening agent, it is only necessary to apply a clear paint to protect the cover when finishing the paint surface of the golf ball.
The application operation becomes easier as compared with the case where enamel paint and clear paint are applied in order. Further, when painted with primer paint, enamel paint or clear paint, or painted with primer paint, clear paint or enamel paint or clear paint, the white appearance is not impaired even if the cover is exposed.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The cover material for golf balls of the present invention contains a white material such as a white pigment to give a white color. As the white pigment, for example, titanium dioxide, zinc oxide, calcium carbonate, lead white and the like may be used. A stilbenebisbenzoxazole derivative having the above formula is blended in the golf ball cover material as a fluorescent whitening agent. The amount of the stilbene bisbenzoxazole derivative is 0.01 to 100 parts by weight of a base resin such as an ionomer resin constituting the cover material.
It may be 0.03 parts by weight.

Specific examples of the stilbene bisbenzoxazole derivative include, for example, 4- (2-benzoxazolyl) -4 '-(5-methyl-2-benzoxazolyl) stilbene and 4,4'-bis (5-methyl) It is preferable to use -2-benzoxazolyl) stilbene or 4,4'-bis (2-benzoxazolyl) stilbene. A mixture of two or more of these may be used.

[0010] The cover material has a Shore D hardness of 5
It is preferable to use a composition comprising 50 to 95 parts by weight of an ionomer resin having 5 to less than 80 and 5 to 50 parts by weight of a diene rubber, wherein the diene rubber is dispersed in the ionomer resin with a particle diameter of 5 μm or less. With this configuration, the flight performance (repulsion), hit feeling, and spin performance of the golf ball are further improved.

The ionomer resin has an ethylene-unsaturated carboxylic acid copolymer as a base resin,
For example, it can be obtained from an ethylene-unsaturated carboxylic acid copolymer and a metal compound capable of supplying a cation. Ethylene-
The unsaturated carboxylic acid copolymer is, for example, a copolymer of ethylene and an unsaturated carboxylic acid having 3 to 6 carbon atoms, such as acrylic acid, methacrylic acid, maleic acid, fumaric acid, or vinyl benzoate. .

Metal compounds capable of supplying cations include, for example, formate, acetate, nitrate, carbonate, bicarbonate, oxide, hydroxide of alkali metals, alkaline earth metals, transition metals and the like. Alkoxide and the like. Examples of the type of metal include Na, Zn, Li, Mg, Mn, Ca, Co, and K. This ionomer resin has a Shore D hardness of 55 or more and less than 80 (55 ≦ Shore D hardness <80). Shore D
The reason for setting the hardness to 55 or more is that the higher the hardness of the ionomer resin, the higher the rebound resilience. On the other hand, when the Shore D hardness is 80 or more, even if butadiene rubber is mixed, the effect is not obtained, and the shot feeling of the obtained golf ball becomes too hard.

As the ionomer resin, for example,
A metal salt of a copolymer of ethylene and methacrylic acid is exemplified. This ionomer resin may be a commercially available one. For example, Himilan 1605, Himilan 1706, and Himilan 17 manufactured by Du Pont-Mitsui Polychemicals, Inc.
07, High Milan AM7315, High Milan AM731
7, Himilan AM7318, Surlyn 7930 and Surlyn 7940 manufactured by DuPont.

As the diene rubber, for example, natural rubber, butadiene rubber, isoprene rubber, styrene-butadiene copolymer rubber, ethylene-propylene-diene copolymer rubber, acrylonitrile-butadiene copolymer rubber may be used. . Of these, it is preferable to use butadiene rubber. As the butadiene rubber, a commercially available product may be used, but a butadiene rubber having a cis-1,4 structure of 40% or more is preferably used.

The composition constituting the cover material comprises 50 to 95 parts by weight of the ionomer resin and 5 to 50 parts by weight of the butadiene rubber. If the amount of the ionomer resin is less than 50 parts by weight, the hardness of the cover decreases and the shot feeling is too soft. On the other hand, if it exceeds 95 parts by weight, the softening by the diene rubber becomes insufficient and the shot feeling is too hard. I will.

In this composition, the diene rubber is dispersed in the ionomer resin with a particle size of 5 μm or less. The particle size is preferably from 0.1 μm to 5 μm
It is good. This is because by making the particle diameter as small as 5 μm or less, resilience, durability and appearance are improved.
In this composition, the diene rubber is preferably thermally crosslinked. Here, thermal crosslinking means that the uncrosslinked diene rubber is crosslinked only by heat without using a crosslinking agent (crosslinking is performed only by heating). If the diene rubber is not thermally crosslinked, the resilience, durability, and appearance of the cover will deteriorate. Here, the deterioration of the appearance means that the cover is fluffed and the appearance is deteriorated.

When the diene rubber is cross-linked by using an organic peroxide as a cross-linking agent, the ionomer resin is also cross-linked at the same time. Therefore, the fluidity of the cover material composition comprising the ionomer resin and the diene rubber is significantly reduced, and Impossible. Further, when the crosslinking is carried out with a sulfur-based vulcanizing agent, there is a problem that the cover material composition is colored yellow and the commercial value is reduced. On the other hand, such a problem does not occur when crosslinking is performed only by heat without using a crosslinking agent. In particular, when cross-linking is performed only with heat, as compared with the case where cross-linking is performed with a sulfur-based vulcanizing agent, resilience is improved.

In order to produce the above composition constituting the cover material, the ratio of the viscosity of the ionomer resin at the melting temperature of the ionomer resin to the viscosity of the diene rubber at the same temperature (diene rubber / ionomer resin) is determined. An ionomer resin and a diene rubber of 1/1 to 5/1 are mixed with the ionomer resin 5 at a melting temperature of the ionomer resin (130 ° C. to 260 ° C.).
It is advisable to mix the diene rubber in a ratio of 10 to 50 parts by weight with respect to 0 to 90 parts by weight. Thereby, the diene rubber can be dispersed in the ionomer resin with a particle size of 5 μm or less.

When the viscosity ratio is larger than 5/1, the difference in viscosity between the ionomer resin and the diene rubber increases, and no shearing force is applied during mixing, so that the diene rubber does not disperse finely. On the other hand, when the viscosity ratio is smaller than 1/1, the viscosity of the ionomer resin becomes larger than that of the diene rubber, so that the ionomer resin has a structure in which the ionomer resin is finely dispersed in the diene rubber.
The mixing is preferably performed at a shear rate of 1000 / sec or more. If the shear rate is less than 1000 / sec, the diene rubber cannot have a particle size of 5 μm or less. As a mixer used for this mixing, it is preferable to use a twin-screw extruder.

[0020]

EXAMPLES With respect to cover materials having the composition shown in Table 1 (parts by weight) (Examples 1 and 2 and Comparative Examples 1 to 3), their whiteness, yellowness and weather resistance (fade meter, 63 ° C.) are described below.
Was evaluated. The results are shown in Table 1 and FIGS. A blooming test was performed on these cover materials. Table 2 shows the results. Here, the fade meter refers to a meter that observes a color change due to light by irradiating black light, and 63 ° C. is a temperature at the time of irradiation.

Evaluation method of whiteness : ASTM E-313
0 hours, 50 hours, 100 hours, 1 according to -73
The whiteness after 50 hours and 200 hours was indicated by white index. The higher the value, the whiter (WI (313)). Here, “WI” refers to whiteness (degree representing whiteness),
The perfect diffuse reflection surface (ideal white) is assumed to have a whiteness of 100,
As the distance from the ideal white color increases, the numerical value of whiteness decreases. "(313)" means ASTM E-3
13 is shown.

FIG. 1 shows the relationship between whiteness and elapsed time. The degree of whiteness decreases with the passage of time, and the smaller the degree of decrease, the better the weather resistance. Evaluation method of yellowness : 0 hour, 50 hours, 100 hours, 150 hours, 2 hours according to ASTM E-313-73.
The yellowness at the time of 00 hours was indicated by a yellow index. The larger the value, the more yellow (YI (313)). Here, “YI”
Means the degree of yellowness, that is, the degree of separation from white in the yellow direction. The ideal white color has almost zero yellowness. As the yellow increases, the value of the yellowness increases as the distance from the ideal white increases. The yellowness is positive when the hue is away from white in the yellow direction, and negative when it is in the blue direction.
“(313)” indicates that it conforms to ASTM E-313.

FIG. 2 shows the relationship between the yellowness and the elapsed time. As the time elapses, the yellowness increases (the numerical value increases), and the smaller the rate of increase, the better the weather resistance.

[0024]

[Table 1]

Note) RESIN H1605: H1706: Titanium oxide: Ultramarine = 50: 50: 2.45: 0.013 (H1605 Himilan 1605, an ionomer resin manufactured by Mitsui Dupont Polychemical Co., Ltd.) Resin Titanium oxide CR-60-2, manufactured by Ishihara Sangyo Co., Ltd. Ultramarine ♯1900, manufactured by Dai-ichi Kasei Co., Ltd.) Hos. KS-N Hostalux KS-N Hoechst, fluorescent bleach Methylated (2-benzoxazolyl) stilbene, mainly 4- (2-benzoxazolyl) -4 '-(5-methyl-2-benzoxazolyl) stilbene, 4,4'-bis (5-methyl-2- Benzoxazolyl) stilbene and 4,4'-bis (2-benzoxazolyl) stilbene) Hos. KS Hostalux KS manufactured by Hoechst Co., Inc. Mainly 4- (2-benzoxazolyl) -4 '-(5-methyl Eas. OB-1) 2-as benzoxazolyl) stilbene, containing 4,4'-bis (5-methyl-2-benzoxazolyl) stilbene and 4,4'-bis (2-benzoxazolyl) stilbene as isomers Eastbright OB-1 Eastman Chemical, fluorescent bleach (4,4'-bis (2-benzoxazolyl) stilbene) Uvt. OB Uvitex OB, Ciba-Geigy, fluorescent bleach (2,5-bis (2-benzoxazolyl) Thiophene) Leuc.EGM Loucopure EGM, manufactured by Sandos, fluorescent bleach (7- (2H-naphthol (12-di) 2-triazoyl) 3-phenylcoumarin)

As is clear from Table 1, Examples 1 and 2 have higher initial whiteness and lower yellowness than Comparative Examples 1 to 3. Moreover, as can be seen from FIGS. 1 and 2, Examples 1 and 2 are more excellent in weather resistance than Comparative Examples 1 to 3.

Blooming test : In a thermostat at 60 ° C.
After leaving the sample of each cover material for 12 hours, the surface of the sample was wiped off with gauze to which toluene was attached, the gauze was illuminated with black light, and the color transfer of the fluorescent whitening agent was visually evaluated by a 5-point method. “5” indicates a good case without color transfer, and “1” indicates a bad case with color transfer.

[0028]

[Table 2]

Table 2 shows that Example 2 is the same as Comparative Example 1, but Example 1 is superior to Comparative Examples 1-3. Therefore, according to the present invention, the color transfer of the fluorescent whitening agent is not increased (that is, the blooming resistance is maintained).

[0030]

As described above, according to the present invention, since a specific stilbenebisbenzoxazole derivative is contained in a golf ball cover material as a fluorescent whitening agent, the weather resistance and whiteness of the cover material are reduced. Can be improved.

[Brief description of the drawings]

FIG. 1 is a diagram showing the relationship between elapsed time of a cover material and whiteness.

FIG. 2 is a diagram illustrating the relationship between the elapsed time of a cover material and the degree of yellowness.

Claims (4)

[Claims] [Claim 1] The following formula: A golf ball cover material containing a stilbene bisbenzoxazole derivative having the following as a fluorescent whitening agent. 2. The method according to claim 1, wherein the stilbenebisbenzoxazole derivative is 4- (2-benzoxazolyl) -4 ′-(5-methyl-2-
Benzoxazolyl) stilbene, 4,4'-bis (5-methyl
2-benzoxazolyl) stilbene and 4,4'-bis
The golf ball cover material according to claim 1, which is at least one member selected from the group consisting of (2-benzoxazolyl) stilbene. 3. The golf ball cover material according to claim 1, wherein the stilbene bisbenzoxazole derivative is contained in an amount of 0.01 to 0.03 parts by weight based on 100 parts by weight of the base resin constituting the cover material. 4. A golf ball having a core covered with a cover, wherein the cover is made of the cover material according to claim 1.