JP2002293996A - Rubber composition for solid golf ball and the solid golf ball - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solid golf ball improved in a carry distance, durability and a ball hit feeling, and to provide a rubber composition for producing the solid golf ball. SOLUTION: This rubber composition for solid golf ball comprises a total of 100 pts.wt. (a) 50-100 pts.wt. of a modified polybutadiene rubber 80-100 mol% in 1,4-cis linkage content, 0-2 mol% in 1,2-vinyl linkage content, modified with a compound bearing alkoxysilyl group and (b) 50-0 pt(s).wt. of a diene rubber other than the component (a), (c) 10-50 pts.wt. of a crosslinkable monomer, (d) 5-80 pts.wt. of an inorganic filler and (e) 0.1-10 pt(s).wt. of an organic peroxide.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a rubber composition for a solid golf ball and a solid golf ball. More specifically, the present invention relates to a rubber composition that provides a solid golf ball having a good shot feeling, a large flight distance (carry), and excellent durability, and a solid golf ball obtained from the composition.

[0002]

2. Description of the Related Art Solid golf balls are one-piece solid golf balls made of a crosslinked product obtained by integrally molding a rubber composition, and solid golf balls made of a crosslinked product of a hard rubber composition.
There are multi-piece solid golf balls such as a two-piece solid golf ball, a three-piece solid golf ball, and a four-piece solid golf ball in which a cover is coated on a solid core having a three-layer structure. Of these solid golf balls, multi-piece solid golf balls have recently become the mainstream of round golf balls because of their excellent flight distance. However, this multi-piece solid golf ball has the disadvantage that the shot feeling is harder than conventionally used wound golf balls. Therefore, attempts have been made to improve the hitting feeling of a multi-piece solid golf ball by making the core softer and softer as it approaches the center, so that the core is softened when hit. However, by making the core soft, durability and resilience performance (flying distance) are reduced. Therefore, the appearance of a multi-piece solid golf ball having a good shot feeling, a long flight distance, and excellent durability has been desired. One-piece solid golf balls, on the other hand, are mainly used as golf balls for driving ranges. However, since cracks and chips are likely to occur due to repeated hits, they are excellent in that they can be prevented as much as possible. Durability is required. Furthermore, golf practitioners demand that the shot feeling be good.

Conventionally, the core of a multi-piece solid golf ball and the core (solid center) of a one-piece golf ball have a 1,4-cis bond content of 80 mol synthesized using a nickel catalyst or a cobalt catalyst. %
Rubber composition containing polybutadiene having the above,
Since it has high resilience and durability, it is preferably used. It is also known that polybutadiene synthesized using a rare earth element-based catalyst can be used for similar applications.

For example, Japanese Patent Publication Nos. 3-59931, 6-80123, 2678240, 6-79018, and 11-319
No. 148 discloses that a rubber composition using a rare earth element polybutadiene is suitable for golf ball applications. However, the obtained golf ball has not obtained sufficient performance in terms of resilience performance and durability. Also, sufficient performance has not been obtained in terms of manufacturing workability. JP-A-7-268132 discloses a golf ball using a rubber composition containing polybutadiene as a main component by a rare earth element-based catalyst modified with a tin compound. However, since the ratio (Mw / Mn) between the weight average molecular weight (Mw) and the number average molecular weight (Mn) is large, sufficient resilience performance and durability are not obtained.
JP-A-11-164912 discloses that a 1,4-cis bond content is 80 mol% or more and a 1,2-vinyl bond content is 2 mol% or more.
It discloses that a rubber modified with polybutadiene is used, which has a mol% or less and a ratio (Mw / Mn) between the weight average molecular weight (Mw) and the number average molecular weight (Mn) is as small as 3.5 or less. However, the manufacturing workability is not sufficient, and there is still room for further improvement in resilience performance and durability.

[0005]

SUMMARY OF THE INVENTION The present invention has improved flight distance, durability and shot feeling, and has excellent workability in manufacturing.
An object of the present invention is to provide a rubber composition capable of providing a solid golf ball. Another object of the present invention is to provide a solid golf ball having improved flight distance, durability and shot feel.

[0006]

According to the present invention, the following rubber composition for a solid golf ball and a solid golf ball are provided to achieve the above object of the present invention. [1] (a) A polybutadiene rubber having a 1,4-cis bond content of 80 to 100 mol%, a 1,2-vinyl bond content of 0 to 2 mol%, and a polybutadiene rubber modified with a compound having an alkoxysilyl group of 50 to 100 (B) 50 to 0 parts by weight of a diene rubber other than the component (a) [where the total amount of the components (a) and (b) is 100 parts by weight], and (c) crosslinkability. 10 to 50 parts by weight of monomer, (d) inorganic filler 5
A rubber composition for a solid golf ball, comprising 80 parts by weight and (e) 0.1 to 10 parts by weight of an organic peroxide. [2] (a) The ratio (Mw / M) between the weight average molecular weight (Mw) and the number average molecular weight (Mn) of the modified polybutadiene rubber
The rubber composition for a solid golf ball according to the above [1], wherein n) is from 1.0 to 3.5. [3] (a) The modified polybutadiene rubber having a Mooney viscosity [ML _{1 + 4} (100 ° C.)] of 30 to 100.
The rubber composition for a solid golf ball according to [1] or [2]. [4] The above-mentioned [1] to [1], wherein the component (a) is a modified polybutadiene rubber obtained by polymerization using a rare earth element-based catalyst and subsequently reacting with a compound having an alkoxysilyl group.
[3] The rubber composition for a solid golf ball according to any one of the above. [5] The above, wherein the rare earth element-based catalyst is a neodymium-based catalyst
The rubber composition for a solid golf ball according to [4]. [6] The rubber composition for a solid golf ball according to any one of the above [1] to [5], wherein the compound having an alkoxysilyl group is an alkoxysilane compound having at least one epoxy group or isocyanate group in a molecule. [7] The above-mentioned [1], wherein the compound having an alkoxysilyl group is 3-glycidyloxypropyltrimethoxysilane.
-The rubber composition for a solid golf ball according to any one of [6] to [6]. [8] A part or all of the rubber material of the solid golf ball is obtained by crosslinking and molding the rubber composition for a solid golf ball according to any one of the above [1] to [7]. Solid golf ball.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, the component (a) of the rubber composition for a solid golf ball of the present invention (hereinafter, also simply referred to as "rubber composition") will be described. As mentioned above,
The modified polybutadiene rubber modified with a compound having an alkoxysilyl group as the component (a) has a 1,4-cis bond content (cis content) of 80 to 100 mol%, preferably 90 to 90 mol%.
-100 mol%, 1,2-vinyl bond content (vinyl content) is 0-2 mol%, preferably 0-1.5 mol%, and the ratio of weight average molecular weight (Mw) to number average molecular weight (Mn) ( Mw / Mn) is preferably 1.0 to 3.5, more preferably 1.0 to 3.3, and the Mooney viscosity [ML _{1 + 4} (1
00 ° C.)] is preferably 30 to 100, more preferably 50 to 90, and a 5% by weight toluene solution viscosity (SV) is preferably 150 to 1,500 cPs, more preferably 200 to 1,500 cPs. (A) If the 1,4-cis bond content (cis content) of the modified polybutadiene rubber is less than 80 mol%, the rebound performance is inferior. Further, the 1,2-vinyl bond content (vinyl content) is 2
Even if it exceeds mol%, the rebound performance is inferior. Further, when the Mw / Mn of the component (a) exceeds 3.5, the repulsion performance and durability are poor. Further, the Mooney viscosity of the component (a) [ML _{1 + 4} (1
(00 ° C.)] is less than 30, the resilience performance and durability are poor. On the other hand, when it exceeds 100, the manufacturing workability is poor. Further, when the viscosity (SV) of the 5% by weight toluene solution of the component (a) at 25 ° C. is less than 150 cPs, the repellency is poor.

The modification of polybutadiene with a compound having an alkoxysilyl group is carried out, for example, by adding a compound having an alkoxysilyl group to a rubber solution after polymerization and reacting. The modified polybutadiene rubber is preferably produced by polymerizing butadiene in the presence of a rare-earth element-based catalyst exhibiting pseudo-living polymerizability and subsequently reacting a compound having an alkoxysilyl group. The rubber composition of the present invention contains, as a main rubber component, a polybutadiene rubber having a large content of 1,4-cis bond content, a narrow molecular weight distribution, and a high solution viscosity, and an alkoxysilyl group. By modifying polybutadiene with a compound having the following, a rubber composition having excellent production workability can be obtained. Furthermore, a solid golf ball having a rubber composition composed of a crosslinked molded article of the rubber composition of the present invention has a long flight distance, and results in excellent shot feeling and durability.

As the rare earth element catalyst used for the polymerization of butadiene, known catalysts can be used.
For example, a catalyst comprising a combination of a lanthanum series rare earth element compound, an organoaluminum compound, an alumoxane, a halogen-containing compound, and if necessary, a Lewis base can be used. Lanthanum series rare earth element compounds include metal halides of atomic numbers 57 to 71, carboxylates,
Alcoholates, thioalcoholates, amides and the like are used. As the organic aluminum compound, AlR
¹ R ² R ³ (where R ¹ , R ² , and R ³ are the same or different and each represent hydrogen or a hydrocarbon residue having 1 to 8 carbon atoms) is used. Alumoxane is a compound having a structure represented by the following formula (I) or the following formula (II). Also, Fine Chemical, 2
3, (9), 5 (1994); Am. Chem. S
oc. , 115, 4971 (1993); Am. C
hem. Soc. , 117, 6465 (1995).

[0010]

Embedded image

(Wherein R ⁴ is a hydrocarbon group containing 1 to 20 carbon atoms, and n is an integer of 2 or more.)

As the halogen-containing compound, AlX _n R ⁵
_3-n (where X is halogen and R ⁵ is
-20 hydrocarbon residues, for example, an alkyl group, an aryl group, or an aralkyl group, and n is 1, 1.5, 2, or 3);
₃ SrCl, Me ₂ SrCl ₂ , MeSrHCl ₂ , MeS
Strontium halides such as rCl ₃ ; and other metal halides such as silicon tetrachloride, tin tetrachloride, and titanium tetrachloride are used. Lewis bases are used to complex lanthanide series rare earth compounds. For example, acetylacetone, Kent alcohol and the like are preferably used. Above all, the use of neodymium-based catalysts using neodymium compounds as lanthanum series rare earth compounds,
Polybutadiene rubber having a high content of 1,4-cis bonds and a low content of 1,2-vinyl bonds can be obtained with excellent polymerization activity. Specific examples of these rare earth element-based catalysts are disclosed in JP-B-62-1404, JP-B-63-64444, JP-A-11-35633, JP-A-10-306113, and JP-A-2000-2000 by the present applicant. −
It is described in each specification of JP-A-34320 and can be used.

Further, a lanthanum series rare earth element compound (L
When a butadiene is polymerized in the presence of a rare earth element-based catalyst using the (a-based compound), the butadiene / La-based compound is required to have a cis content and Mw / Mn within the above ranges.
1,000 to 2,000,000, especially 5,000 to 1 in molar ratio
It is preferable that the amount is 100,000, and AlR ¹ R ² R ³ /
The La-based compound has a molar ratio of 1 to 1,000, particularly 3 to 1,000.
It is preferably 500. Further, the molar ratio of the halogen compound / La-based compound is 0.1 to 30, especially 0.2 to 30.
It is preferably from 15 to 15. The molar ratio of the Lewis base / La-based compound is preferably 0 to 30, particularly preferably 1 to 10. In the polymerization, a solvent may be used, or bulk polymerization or gas phase polymerization may be performed without using a solvent. The polymerization temperature is usually -30C to 150C, preferably 10 to
100 ° C.

The modified polybutadiene rubber can be obtained by reacting a compound having an alkoxysilyl group at the active terminal of the polymer, following the above polymerization. As the compound having an alkoxysilyl group, an alkoxysilane compound having at least one epoxy group or isocyanate group in a molecule is preferably used. Specific examples include 3-glycidyloxypropyltrimethoxysilane, 3-glycidyloxypropyltriethoxysilane, (3-glycidyloxypropyl) methyldimethoxysilane, (3-glycidyloxypropyl) methyldiethoxysilane, β- (3 , 4-epoxycyclohexyl) trimethoxysilane, β- (3,4-epoxycyclohexyl) triethoxysilane, β- (3,4-epoxycyclohexyl) methyldimethoxysilane, β-
Epoxy group-containing alkoxysilanes such as a condensate of (3,4-epoxycyclohexyl) ethyldimethoxysilane, 3-glycidyloxypropyltrimethoxysilane, and a condensate of (3-glycidyloxypropyl) methyldimethoxysilane; 3-isocyanatopropyl Condensate of trimethoxysilane, 3-isocyanatopropyltriethoxysilane, (3-isocyanatopropyl) methyldimethoxysilane, (3-isocyanatopropyl) methyldiethoxysilane, 3-isocyanatopropyltrimethoxysilane, (3 Isocyanate group-containing alkoxysilane compounds such as a condensate of (isocyanatopropyl) methyldimethoxysilane.

When the compound having an alkoxysilyl group is reacted with an active terminal, a Lewis acid may be added to accelerate the reaction. The Lewis acid promotes the coupling reaction as a catalyst, improving the cold flow of the modified polymer and improving the storage stability. Specific examples of Lewis acids include dialkyltin dialkyl malates,
Examples thereof include dialkyltin dicarboxylate and aluminum trialkoxide.

The modification method using the above terminal modifier is as follows.
A method known per se can be used. For example, a method described in JP-A-11-35633 by the present applicant, a method described in JP-A-7-268132, and the like can be adopted.

Next, the diene rubber other than the component (a) which is the component (b) will be described. The component (b) is not an essential component of the rubber composition of the present invention, but is a component that is optionally blended within a range that does not impair the achievement of the object of the present invention. Specific examples of the component (b) include unmodified or modified polybutadiene rubber, styrene butadiene rubber (SBR), natural rubber, and synthetic polyisoprene rubber having a cis content of less than 80 mol% or an Mw / Mn of more than 3.5. ,
Examples include ethylene propylene diene rubber (EPDM). These can be used alone or in combination of two or more.

Next, the crosslinkable monomer as the component (c) will be described. The crosslinkable monomer (c) is polymerized by radicals generated by decomposition of an organic peroxide described below, which functions as a radical initiator, and promotes crosslinking of the components (a) and (b). Act like so. The crosslinkable monomer compounded in the rubber composition of the present invention is preferably a monovalent or divalent metal salt of an α, β-ethylenically unsaturated carboxylic acid, and specific examples thereof include the following. Can be.

(I) Acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, sorbic acid, tiglic acid, cinnamic acid, and aconitic acid. These can be used alone or in combination of two or more. (Ii) Zn, Ca, Mg, B of the unsaturated acid of (i) above
a and each salt of Na. These may be used alone or 2
More than one species can be used in combination. The unsaturated acid (i) and the metal salt (ii) can be used in combination. The metal salt of the above α, β-ethylenically unsaturated carboxylic acid may be used in a rubber composition prepared by kneading a metal oxide such as zinc oxide in advance, in addition to the usual method of mixing the metal salt with a base rubber or the like as it is. An α, β-ethylenically unsaturated carboxylic acid such as acrylic acid or methacrylic acid is added, kneaded and reacted in the rubber composition with the α, β-ethylenically unsaturated carboxylic acid and a metal oxide,
It may be a metal salt of an α, β-ethylenically unsaturated carboxylic acid. (C) The crosslinkable monomer can be used alone or in combination of two or more.

Next, the inorganic filler as the component (d) will be described. The inorganic filler (d) reinforces the crosslinked rubber to improve the strength, and can adjust the weight of the solid golf ball depending on the compounding amount. Specific examples of the inorganic filler include zinc oxide, barium sulfate, silica, alumina, aluminum sulfate, calcium carbonate, aluminum silicate, and magnesium silicate. Especially, use of zinc oxide, barium sulfate, and silica is preferable. These inorganic fillers can be used alone or in combination of two or more.

Next, the organic peroxide as the component (e) will be described. (E) blended in the rubber composition of the present invention
The organic peroxide acts as an initiator of a rubber component composed of the component (a) and the component (b), and a crosslinking reaction, a graft reaction, a polymerization reaction, and the like of the (c) crosslinkable monomer. Preferred examples of the organic peroxide include, for example, dicumyl peroxide, 1,1-bis (t-butylperoxy) -3,3,5-trimethylcyclohexane, 2,5
-Dimethyl-2,5-di- (t-butylperoxy) hexane, 1,3-bis (t-butylperoxy-isopropyl) benzene and the like.

The above components (a) and (b) contained in the rubber composition of the present invention, (c) a crosslinkable monomer,
The proportions of (d) the inorganic filler and (e) the organic peroxide are as follows. (A) 50-100 parts by weight of a modified polybutadiene rubber,
(B) 50 to 0 parts by weight of a diene rubber other than the component (a), preferably 40 to 100 parts by weight.
0 parts by weight [where the total amount of the components (a) and (b) is 100 parts by weight]. In the components (a) and (b), if the amount of the component (a) is less than 50 parts by weight, the resilience of the solid golf ball is not sufficient, and the initial speed does not increase and the flight distance does not increase. Not preferred. The amount of the (c) crosslinking monomer is 10 to 50 parts by weight, preferably 10 to 40 parts by weight, based on 100 parts by weight of the total of the components (a) and (b). If the amount is less than 10 parts by weight, the resilience of the solid golf ball is not sufficient, so that the initial speed is reduced and the flight distance is reduced.
If the amount exceeds 0 parts by weight, the ball becomes too hard and the shot feeling becomes poor.

(D) The amount of the inorganic filler is from (a) to
It is 5 to 80 parts by weight, preferably 5 to 70 parts by weight, based on 100 parts by weight of the total amount of the component (b). If the amount is less than 5 parts by weight, the obtained solid golf ball will be too light, while if it exceeds 80 parts by weight, the obtained solid golf ball will be too heavy. The amount of the organic peroxide (e) is 0.1 to 10 parts by weight, preferably 0.2 to 5 parts by weight, based on 100 parts by weight of the total of the components (a) and (b). If the amount is less than 0.1 part by weight, the golf ball becomes too soft and the resilience deteriorates, and the flight distance decreases. On the other hand, if it exceeds 10 parts by weight, the ball becomes too hard and the shot feeling deteriorates. When the content ratio of each of the above components is within the above range, a solid golf ball excellent in flight distance, durability and shot feeling can be obtained from the rubber composition of the present invention.

The rubber composition of the present invention may contain, in addition to the above components (a) and (b), (c) a crosslinkable monomer, (d) an inorganic filler, and (e) an organic peroxide, if desired. , A cross-linking aid such as zinc oxide; a lubricant such as stearic acid; an antioxidant;

A typical example of a solid golf ball produced by crosslinking and molding from the rubber composition of the present invention will be described with reference to the drawings. FIG. 1 is a schematic sectional view showing a one-piece solid golf ball. In FIG. 1, reference numeral 1 denotes a main body and 1a denotes a dimple. The main body 1 is made of rubber (that is, rubber made of a cross-linked molded article of the rubber composition of the present invention). FIG. 2 is a schematic sectional view showing a two-piece solid golf ball. Reference numeral 11 denotes a core, and 12 denotes a cover. The cover 12 covers the core 11. And 12a is a dimple. The core 11 is made of rubber.
FIG. 3 is a schematic cross-sectional view showing a three-piece solid golf ball, wherein 21 is an inner core, 22 is an outer core, 23 is a cover, and 23a is a dimple.
In this three-piece solid golf ball, the inner core 21 and the outer core 22 constitute a solid core. The inner core 21 or the outer core 22 is
Alternatively, both the inner core 21 and the outer core 22 are made of rubber. In addition, the density of the outer layer core 22 of the three-piece solid golf ball is
It is preferable that the distance is larger than that in terms of flight distance and rotation speed retention. For example, a filler having a large specific gravity, such as W ₂ O ₅ , is blended in the outer layer core 22, and ZnO ₂ is added to the inner layer core 21.
By blending a filler having a small specific gravity such as, for example, the above can be achieved.

Next, a method for producing a solid golf ball using the rubber composition of the present invention will be described. First, the body portion of the one-piece solid golf ball, the core of the two-piece solid golf ball, and the inner layer core of the three-piece solid golf ball are respectively filled with a rubber composition of the present invention in a predetermined mold, and cross-linked by pressing. . The crosslinking conditions are preferably at a temperature of 130 to 180 ° C. for 10 to 50 minutes. The temperature at the time of this cross-linking molding may be changed in two or more stages. In a three-piece solid golf ball, a rubber composition for an outer layer core is formed into a sheet to a desired thickness on the outer side of the inner layer core obtained as described above, and a two-layer structure is formed by crosslinking with a press. A solid core can be formed. In the three-piece solid golf ball, any of the rubber compositions used for each of the inner layer core and the outer layer core may be the rubber composition of the present invention, and both are preferably the rubber compositions of the present invention. .

The covers of the two-piece solid golf balls and the three-piece solid golf balls are appropriately mixed with an inorganic white pigment such as titanium dioxide and additives such as a light stabilizer, if necessary, in a resin component mainly containing an ionomer resin. It is formed by coating the above-mentioned core with the cover composition thus prepared. For coating, an injection molding method is usually employed, but is not limited thereto. In the case of a one-piece solid golf ball, a desired dimple is formed as necessary when the main body portion is formed, and in the case of a two-piece solid golf ball or a three-piece solid golf ball, when a cover is formed. A four-piece solid golf ball can be produced from the rubber composition of the present invention in the same manner as a three-piece solid golf ball.

[0028]

EXAMPLES The present invention will be described below in detail with reference to examples, but the scope of the present invention is not limited to the examples.

Synthesis Example 1 [Synthesis of Modified Polybutadiene Rubber (A): HPB (A)] In a nitrogen-purged 5 L autoclave, 2.5 kg of cyclohexane and 300 g of 1,3-butadiene were added under nitrogen.
Was charged. To these, neodymium octoate (0.18 mmol) and acetylacetone (0.3) were previously added.
7 mmol), a solution of methylalumoxane (18.5 mmol) in toluene, a solution of diisobutylaluminum hydride (3.9 mmol) in cyclohexane and diethylaluminum chloride (0.37).
0 mmol) of cyclohexane solution, and mixed with 1,3-butadiene (0.9 mol, 5 times mol of neodymium octoate).
0 mmol) and a catalyst aged at 25 ° C. for 30 minutes, and polymerized at 50 ° C. for 30 minutes. The reaction conversion of 1,3-butadiene was almost 100%. Next, the temperature of the polymerization solution was maintained at 50 ° C., and 3-glycidyloxypropyltrimethoxysilane (5.40 mmol) was added. Then, it is left for 30 minutes, and the 2,4-di-t-
A methanol solution containing 1.5 g of butyl-p-cresol was added, and after terminating the polymerization, the solvent was removed by steam stripping and dried with a roll at 110 ° C. to obtain a polymer.
The 1,4-cis bond content of this polymer is 97.8 mol%,
The 1,2-vinyl bond content is 1.0 mol%, Mw / Mn is 2.4, and the Mooney viscosity [ML _{1 + 4} (100 ° C.)] is 4.
1. The viscosity of the toluene solution was 210.

Synthesis Example 2 [Synthesis of modified polybutadiene rubber (B): HPB (B)] The same method as in the synthesis example of HPB (A) was used except that the amount of methylalumoxane was changed to 9.2 mmol. A coalescence was prototyped. Table 1 shows the physical property values of the polymer. Synthesis Example 3 [Modified polybutadiene rubber (C): HPB
Synthesis of (C)] A polymer was trial-produced in the same manner as in the synthesis example of HPB (A), except that the addition amount of methylalumoxane was changed to 9.2 mmol and the addition amount of diisobutylaluminum hydride was changed to 4.5 mmol. did. Table 1 shows the physical property values of the polymer. Synthesis Example 4 [Modified polybutadiene rubber (D): HPB
Synthesis of (D)] A prototype polymer was produced in the same manner as in the synthesis example of HPB (A), except that the addition amount of methylalumoxane was changed to 9.2 mmol and the addition amount of diisobutylaluminum hydride was changed to 3.2 mmol. did. Table 1 shows the physical property values of the polymer.

Synthesis Example 5 [Synthesis of Modified Polybutadiene Rubber (E): HPB (E)] HPB was changed except that the addition amount of methylalumoxane was changed to 9.2 mmol and the addition amount of diisobutylaluminum hydride was changed to 5.0 mmol. A polymer was experimentally produced in the same manner as in the synthesis example of (A). Table 1 shows the physical property values of the polymer. Synthesis Example 6 [Modified polybutadiene rubber (F): HPB
Synthesis of (F)] A prototype polymer was produced in the same manner as in the synthesis example of HPB (A), except that the addition amount of methylalumoxane was changed to 9.2 mmol and the addition amount of diisobutylaluminum hydride was changed to 1.6 mmol. did. Table 1 shows the physical property values of the polymer. Synthesis Example 7 [Modified polybutadiene rubber (G): HPB
Synthesis of (G)] A polymer was trial-produced in the same manner as in the synthesis example of HPB (A), except that the amount of methylalumoxane added was changed to 5.1 mmol. Table 1 shows the physical property values of the polymer. Synthesis Example 8 [Modified polybutadiene rubber (H): HPB
Synthesis of (H)] Except that the amount of methylalumoxane added was changed to 9.2 mmol and the modifier was changed to polymeric type diphenylmethane isocyanate (5.4 mmol),
A polymer was experimentally produced in the same manner as in the synthesis example of PB (A).
Table 1 shows the physical property values of the polymer.

HPB (H) is disclosed in Japanese Patent Application Laid-Open No. H11-164912.
Comparative modified polybutadiene rubber using a modifying agent (polymeric type diphenylmethane diisocyanate) described in Japanese Patent Application Laid-open No.
03, BR11 and BR18 are unmodified polybutadiene rubbers without using a modifier. The solution viscosity in Table 1 (S
V) was measured in a 25 ° C. thermostat using a Cannon-Fenske viscometer for a toluene solution containing 5% by weight of a previously prepared polymer.

[0033]

[Table 1]

BR01: Polybutadiene rubber manufactured by JSR Corporation BR03: Polybutadiene rubber manufactured by JSR Corporation BR11: Polybutadiene rubber manufactured by JSR Corporation BR18: Polybutadiene rubber manufactured by JSR Corporation Si: 3-glycidyloxypropyl Trimethoxysilane MDI: Polymeric type diphenylmethane diisocyanate

Examples 1 to 6 and Comparative Examples 1 to 4 Using various polybutadienes shown in Table 1 above, the polybutadienes were blended in the composition shown in Table 2 below to obtain zinc diacrylate, zinc oxide, dicumyl peroxide and an antioxidant. Was kneaded with a roll, and the obtained rubber composition was pressure-crosslinked at 150 ° C. for 30 minutes to obtain a core having a diameter of 38.5 mm. Further, in order to compare manufacturing workability, a winding property test was performed with a 6-inch roll to evaluate roll workability. Conditions for winding test: temperature 70 ° C, nip width 1.4m /
m, rotation speed 20 rpm / 24 rpm.

Here, the evaluation of roll workability was determined as follows. In addition, the larger the numerical value, the better the roll workability (the same applies to the evaluations in Tables 3 and 4). 5: Wraps around the roll neatly and has a smooth surface. 4: Winding around the roll, no roughness on the surface. 3: Winding around the roll, but the surface is rough. 2: winding around the roll, but with holes on the surface and dirty. 1: Does not wind around the roll.

From Table 2, it can be seen that the roll workability of Examples 1 to 6 is superior to Comparative Examples 1 to 4.

Next, the obtained core was coated with a cover composition comprising a mixture of 100 parts by weight of an ionomer resin (trade name: Surlyn, manufactured by DuPont) and 2 parts by weight of titanium dioxide by an injection molding method. To form
A two-piece solid golf ball having an outer diameter of 42.7 mm was produced. Comparative Examples 2 and 3 are described in JP-A-11-16149.
It was prepared by using a modifier (polymeric type diphenylmethane diisocyanate) described in JP-A No. 2 (Kokai). Comparative Example 4 is a conventional standard two-piece solid golf ball. With respect to the obtained two-piece solid golf ball, its weight, compression (indicated by PGA), initial ball speed, flight distance, and hammering durability were measured. Table 2 shows the results. Also, the obtained solid golf balls were hit with a No. 1 wood club by 10 top professional golfers, and the shot feeling was examined. The results are also shown in Table 2.

The method for measuring the ball initial speed, the flight distance and the hammering durability and the method for evaluating the feel at impact are as follows. (1) Initial ball speed: A No. 1 wood club was attached to a swing robot manufactured by True Temper, and the ball was hit at a head speed of 45 m / sec.
Seconds). (2) Flying distance (carry): The No. 1 wood club was attached to a swing robot manufactured by True Temper, and the distance (yard) to the ball drop point when the ball was hit at a head speed of 45 m / sec was measured. (3) Hammering durability: The ball was repeatedly hit with a collision plate at a speed of 45 m / sec, the number of hits until the ball was broken was checked, and the index of the number of times until the ball of Comparative Example 4 was broken was set to 100. Indicated by

(4) Evaluation Method for Shot Feeling: Top Pro 10
It was evaluated by a real hit test by a person. In evaluating the feel at impact, the ball of Comparative Example 4 which is a conventional standard two-piece solid golf ball was evaluated for the feel at impact. The evaluation criteria are as follows, and when the evaluation results are displayed in the table, the same symbols are used. In this case, it is indicated that eight or more out of ten persons who performed the evaluation performed the same evaluation. ing. Evaluation criteria: ：: The shot feeling is softer and better than the ball of Comparative Example 4. Δ: The shot feeling is equivalent to that of the ball of Comparative Example 4. X: The shot feeling is harder and worse than the ball of Comparative Example 4.

From the results shown in Table 2, the balls of Examples 1 to 6 have a longer flight distance and better durability than the balls of Comparative Examples 1 to 3, and have a conventional standard two-piece ball. The shot feeling was good as compared with the solid golf ball of Comparative Example 4.

[0042]

[Table 2]

*) Antioxidant: Yoshinox 425, manufactured by Yoshitomi Pharmaceutical Co., Ltd. **) An index with Comparative Example 4 being 100. The higher the value, the better.

Examples 7 to 12 and Comparative Examples 5 to 8 A rubber composition was prepared by kneading the compounding materials having the compositions shown in Table 3 with a kneader and a roll, and the obtained rubber composition was filled in a mold. Pressure-crosslinking molding was performed at 168 ° C. for 25 minutes to produce a one-piece solid golf ball composed of an integrally molded crosslinked molding having an outer diameter of 42.7 mm. Comparative Examples 6 and 7 were prepared using the modifier (polymeric type diphenylmethane diisocyanate) described in JP-A-11-164912. Comparative Example 8 is a conventional standard one-piece solid golf ball. From Table 3, the roll workability of Examples 7 to 12 is as follows.
It turns out that it is excellent compared with Comparative Examples 5-8.

The obtained one-piece solid golf ball was measured for weight, compression (PGA), ball initial speed, flight distance (carry), and hammering durability in the same manner as in Example 1 to evaluate the feel at impact. Table 3 shows the results. However, in evaluating the feel at impact,
The ball of Comparative Example 8 which is a conventional standard one-piece solid golf ball was used for comparison.

As is clear from the results shown in Table 3,
Even in these one-piece solid golf balls,
The solid golf balls of Examples 7 to 12 were compared with Comparative Examples 5 to 5.
7 compared to the solid golf ball,
In addition, the durability was excellent, and the shot feeling was better than that of the solid golf ball of Comparative Example 8 which is a conventional standard one-piece solid golf ball.

[0047]

[Table 3]

*) An index with Comparative Example 8 being 100.
The higher the number, the better.

Examples 13 to 16 and Comparative Examples 9 to 11 The compounding materials having the compositions shown in Table 4 were kneaded with a kneader and a roll to prepare a rubber composition.
Pressure-crosslinking molding was performed at 0 ° C. for 30 minutes to obtain a core having a diameter of 38.5 mm. Next, the obtained core was coated with a cover composition comprising a mixture of 100 parts by weight of an ionomer resin (trade name: Surlyn, manufactured by DuPont) and 2 parts by weight of titanium dioxide by an injection molding method to form a cover. A two-piece solid golf ball having an outer diameter of 42.7 mm was produced. The obtained two-piece solid golf ball was measured for weight, compression (PGA), initial ball speed, flight distance, and hammering durability in the same manner as in Example 1 to evaluate the feel at impact. Table 4 shows the results. However, in evaluating the feel at impact, the ball of Comparative Example 4 which is a conventional standard two-piece solid golf ball was used for comparison.

As is clear from the results shown in Table 4,
Even in these two-piece solid golf balls,
The solid golf balls of Examples 13 to 16 have a longer flight distance and are more durable than the solid golf balls of Comparative Examples 4 and 9 to 11, and Comparative Example 4 which is a conventional standard two-piece solid golf ball. The shot feeling was better than that of the solid golf ball.

[0051]

[Table 4]

[0052]

The solid golf ball obtained from the rubber composition for a solid golf ball of the present invention has excellent workability, good hit feeling, long flight distance, and excellent durability.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing an example of a one-piece solid golf ball.

FIG. 2 is a schematic sectional view showing an example of a two-piece solid golf ball.

FIG. 3 is a schematic sectional view showing an example of a three-piece solid golf ball.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Main body part 1a, 2a, 3a Dimple 11 Core 21 Inner core 22 Outer core 12, 23 Cover

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08K 3/00 C08K 3/00 5/14 5/14 // (C08L 15/00 C08L 9:00 9: 00) F-term (reference) 4J002 AC052 AC111 DE107 DG047 DJ007 DJ017 EG026 EG036 EG056 EK008 FD017 FD148 GC01 4J015 DA04 DA14 4J028 AA01A AB00A AC49A BA00A BA01B BB00A BB01B BC18B BC25B EA01 EB01 EC01

Claims (8)

[Claims] (1) The 1,4-cis bond content is 80-1.
00 mol%, 1,2-vinyl bond content is 0-2 mol%,
And 50 to 100 parts by weight of a modified polybutadiene rubber modified with a compound having an alkoxysilyl group, and (b) 50 to 0 parts by weight of a diene rubber other than the component (a) [where the components (a) and (b) The total amount of the components is 100 parts by weight], (c) 10 to 50 parts by weight of a crosslinking monomer,
A rubber composition for a solid golf ball, comprising (d) 5 to 80 parts by weight of an inorganic filler and (e) 0.1 to 10 parts by weight of an organic peroxide. 2. The ratio (Mw) between (a) the weight average molecular weight (Mw) and the number average molecular weight (Mn) of the modified polybutadiene rubber.
The rubber composition for a solid golf ball according to claim 1, wherein (/ Mn) is from 1.0 to 3.5. 3. The rubber composition for a solid golf ball according to claim 1, wherein (a) the modified polybutadiene rubber has a Mooney viscosity [ML _{1 + 4} (100 ° C.)] of 30 to 100. 4. The modified polybutadiene rubber according to claim 1, wherein the component (a) is a modified polybutadiene rubber obtained by polymerization using a rare earth element-based catalyst and subsequently reacting a compound having an alkoxysilyl group. A rubber composition for a solid golf ball. 5. The rubber composition for a solid golf ball according to claim 4, wherein the rare earth element-based catalyst is a neodymium-based catalyst. 6. The compound having an alkoxysilyl group is an alkoxysilane compound having at least one epoxy group or isocyanate group in a molecule.
The rubber composition for a solid golf ball according to any one of the preceding claims. 7. A compound having an alkoxysilyl group, wherein
The rubber composition for a solid golf ball according to any one of claims 1 to 6, wherein the rubber composition is glycidyloxypropyltrimethoxysilane. 8. A part or all of the rubber material of the solid golf ball is obtained by cross-linking and molding the rubber composition for a solid golf ball according to any one of claims 1 to 7. Solid golf ball.