JPS6116753A - Golf ball cover material - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention provides golf seel cano material having excellent properties,
For details, trans bond 85 or more, weight average molecular weight (M
w) 30,000 to 300,000, molecular weight distribution (i; jw/un)
1.2 to 50 resin Trans-polybutadiene Zarf i-lucano, which is made by low-temperature vulcanization or electron beam crosslinking of a polymer containing at least 30%, has excellent rebound resilience, impact resistance, and feel on impact. -Relating to materials.

<Prior art> Traditionally, as golf dil copper materials, generally thread-wound corfusères use polymers that crystallize quickly at low temperatures, such as natural, S-shita, and synthetic transpolyisoprene, while two-piece golf dils use ionomers. resin has been used. However, due to physical properties, golf seel materials made of Noronata, transpolyisozolene, etc. have insufficient impact resistance and poor durability, and the crystallization rate is extremely low, especially during rework. There have been problems such as slow vulcanization, difficulty in molding due to the tackiness of the raw material polymer, and extremely poor productivity in low-temperature vulcanization. Golf dur cover material made from ionomer resin has high durability but poor rebound properties, and to improve this it is necessary to increase hardness, which is said to result in poor feel when hitting. Ta.

Various proposals have been made to improve the above-mentioned drawbacks, especially regarding Noronata and transpolyisozolene.
For example, a method of blending a crystallization accelerator to accelerate the crystallization rate (Japanese Patent Application Laid-Open No. 547-1'39955) or a method of blending polynibusilone caprolactone (Japanese Patent Application Laid-open No. 53-5O2S2) is known.

<Problems to be Solved by the Invention> However, the improvement effects of these methods are insufficient, and the costs are high from an industrial perspective, so that the problems have not been completely solved. Furthermore, attempts have been made to use trans-polybutadiene in place of natural trans-polyisozolene for this purpose (Kogyo Zasai, Vol. 10, No. 6, 19-21). Page, 1962)
At that time, transpolybutadiene obtained using a heterogeneous catalyst did not have any performance superior to that of natural balata, and it had not actually been used as a material for golf sale cannons.

Means and Effects for Solving the Problems> The present inventor conducted various studies in order to solve the above-mentioned drawbacks of the golf gel carbon material at once, and developed a method using 404-finger transpolybutadiene with a specific structure as the main raw material. This material is made by low-temperature vulcanization and cross-linking with electron beams, which also solves the disadvantages of poor productivity.The material has excellent rebound resilience, impact resistance, and hardness, which is thought to determine the feel at impact. The present invention was achieved based on the discovery that the balance between the two is excellent.

That is, the present invention has a trans bond of 85% or more, a weight average molecular weight (i) of 3 to 300,000, and a molecular weight distribution (Mw/Mn) of 3 to 300,000.
To provide a golf gel car material made by low-temperature vulcanization and electron beam crosslinking of a diene polymer containing at least 30% of resinous transpolybutadiene of 1.2 to 50%.

The resinous transpolybutadiene, which is the main raw material for the Golf I-Luca and S-materials of the present invention, must have the following structure. First of all, the coupling mode is 85 or more trans-couplings measured by Molekuchi's method using an infrared spectrometer.
Preferably it is 87-93q6. If the hardness is lower than this, the hardness of the material will be insufficient. The weight average molecular weight measured by gel permeation chromatography (apC) is 30,000 to 300,000, preferably 50,000 to 250,000, and more preferably 100,000 to 200,000. If the weight average molecular weight is less than 30,000, the physical properties, especially impact resistance, will be deteriorated, while if the weight average molecular weight is more than 300,000, processing and molding operations will be significantly impaired. Historically, the molecular weight distribution measured by gel permeation chromatography (GPO) is the ratio of the weight average molecular weight (Ni) to the number average molecular weight (Ni) (
mw/yn) is 1.2 to 5.0, preferably 1.5 to 3.0, more preferably 1.8 to z5. A narrow molecular weight distribution of 1.2 or less not only makes pressure molding difficult, but also reduces physical properties, such as impact strength, perhaps due to poor dispersion with other compounding ingredients. If it is 0 or more, the rebound becomes significant. still,
The shape of the molecular weight distribution may be a general monomodal or bimodal or more, and one of the preferred embodiments of the present invention is a bimodal structure using a known cassilling agent. be. Furthermore, the resinous transpolybutadiene of the present invention contains a small amount of copolymerized components, such as monomer units of styrene, isoprene, etc. under a 30-weight plate, in a random or block form in its molecular chain. Good too.

The resinous transpolybutadiene having the structure thus specified is produced by converting sitadiene into a homogeneous catalyst consisting of a barium, strontium or calcium compound and an organolithium compound and/or an organomagnesium compound (optionally an organoaluminium compound), or a rare earth metal. It can be easily obtained by polymerization in the presence of a catalyst consisting of a maple compound and an organomagnesium compound, and when the former catalyst is used, the bonding mode, molecular weight, molecular weight distribution, etc. will depend on the amount of catalyst, composition, and polymerization. It is variable depending on polymerization conditions such as temperature. (@Eha Japanese Patent Publication No. 55-388
27, JP-A-56-112916) The golf course of the present invention contains at least 30%, preferably 50%, of the above-mentioned resinous transpolybutadiene.
It consists of a diene polymer containing the above.

If the content of resinous transpolybut-2ene in the diene polymer is 30% or less, the excellent effects of the present invention will not be exhibited.

One of the preferred embodiments of the present invention is a case where the diene polymer is resinous transpolybutadiene alone. In addition, preferable polymers constituting the tsene polymer other than the resinous transpolybutadiene include transpolyisoprene, cispolyisoprene rubber, rhocis or cis-polybutadiene rubber, and styrene-citadiene co-heptadopolymer rubber. It will be done. A particularly preferred polymer is transpolyisoprene or a mixture of transpolyisoprene and cis-isozolene rubber.

The Golf Dal Cano Z-material of the present invention may optionally contain an inorganic filler. Examples of inorganic fillers include silicic acid, calcium silicate, aluminum silicate, calcium carbonate, titanium dioxide, aluminum oxide, norium sulfate, or mixtures thereof. Further, examples of natural products as inorganic fillers include clay, talc, mica, asbestos, and clay. These inorganic fillers are usually used in an amount of 5 to 100 parts by weight per 100 parts by weight of the polymer. If it is less than 5 parts by weight, the reinforcing effect, coloring effect, etc. which are the objectives of blending the inorganic filler into the polymer cannot be sufficiently achieved. On the other hand, if it exceeds 100 parts by weight, the strength and rebound properties will be significantly lowered, and processing will become difficult. A particularly preferred inorganic filler is titanium oxide (
anatase or rutile type) or silicic acid (finely divided silicic acid), and the preferred amount thereof is 5 to 50 parts by weight, particularly preferably 7.5 to 25 parts by weight. In addition to these inorganic fillers, zinc oxide may be added in an amount of 1 to 1 if necessary.
0 parts by weight may be added.

A low temperature vulcanization method or an electron beam crosslinking method is used for crosslinking the birch resin material of the present invention. Preferred vulcanizing agents for low-temperature vulcanization include elemental sulfur, selenium, tellurium, or inorganic sulfur compounds such as sulfur dichloride and sulfur chloride; organic sulfur compounds such as morpholine disulfide and alkylphenol disulfide. In addition, the vulcanization accelerators include guanidine-based vulcanization accelerators, aldehyde-ammonia-based vulcanization accelerators, sulfenami P unvulcanization accelerators, thiuram-based vulcanization accelerators, xanthate-based vulcanization accelerators, and aldehyde-amine vulcanization accelerators. Examples include vulcanization accelerators, thiazole vulcanization accelerators, thiourea vulcanization accelerators, dithiocal, 6-mate vulcanization accelerators, and mixtures thereof.

A particularly preferred vulcanizing agent is elemental sulfur, the preferred amount used being 0.1 to 10 parts by weight per 100 parts by weight of polymer. Further, preferred vulcanization accelerators are xanthate-based vulcanization accelerators and dithiocarnomate-based vulcanization accelerators.

Examples of xanthate-based vulcanization accelerators include sodium isozorobylxanthate, zinc isozorobylxanthate, zinc ethylxanthate, zinc butylxanthate, dibutylxanthogen disulfide P, and the like. Examples of dithiocarnomate-based vulcanization accelerators include sodium dibutyldithiocarnomate, sodium diethyldithiocarnomate, sodium coulopetyldithiocarnomate, ethylphenyldithiocal/zinc semate, dimethyl Zinc dithiocarbamate, zinc diethyldithiocarnocarbamate, zinc di-n-butyldithiocarnomate, zinc dibenzyldithiocarhamate, zinc N-pentamethylenedithiocarbamate, zinc dimethylpentamethylenedithiocarbamate/zinc dimethylpentamethylenedithiocarbamate , zinc ethyl phenylsithiocarnomate, selenium dimethyldithiocarnomate, selenium diethyldithiocarnosemate, tellurium diethyldithiocarnomate, Pmium diethyldithiocarbamate, dibutylammonium dibutyldithiocarbamate, dibutyl Examples include dibutylammonium dithiocarbamate, diethylamine diethyldithiocarnomate, N,N'-dimethylcyclohexane salt of dibutyldithiocarnomate, piperidine pentamethylenedithiocarnomate, pipecoline methylpentamethylenedithiocarnomate, etc. It will be done. The preferred amount of the vulcanization accelerator used varies depending on the type of vulcanization accelerator used, but is generally 0.1 to 10 parts by weight per 100 parts by weight of the polymer. It is necessary that the temperature of the compound during vulcanization does not exceed the melting point of the resinous polybutadiene used, and it is usually preferable to vulcanize at a temperature of 90° C. or lower. Particularly preferred vulcanization temperature is 30 to 6
It is 0°C. The vulcanization time varies depending on the vulcanizing agent, vulcanization accelerator and vulcanization temperature used, but is usually several tens of minutes to several days.

The vulcanization method of the present invention is an electron beam crosslinking method. In electron beam crosslinking, it is not particularly necessary to mix a vulcanizing agent, and vulcanization is carried out by irradiating a predetermined dose of electron beam with a predetermined intensity as uniformly as possible. Further, if necessary, blending an accelerator may have the effect of increasing the crosslinking efficiency by electron beam irradiation) and/or improving the properties of the crosslinked golf pole strength and material, particularly the rebound properties.

The preferred intensity of the electron beam is Q, 3 MeV to 5 MeV, depending on the thickness of the golf ball cover material. 0
, an electron beam with an intensity lower than 3 MeV cannot be cross-linked uniformly due to the golf pole force/2-internal vibration, and 5 MeV
At higher intensities of the electron beam, the efficiency of the electron beam for crosslinking is significantly reduced.

Further, the preferable electron beam irradiation amount is 105 rad to 10 rad.
It is in the range of 8 rad.

Preferred accelerators in electron beam irradiation are maleimide compounds, thiol compounds, acrylic compounds and mixtures thereof. Among these, maleimide compounds and thiol compounds are particularly preferred.

Examples of maleimide compounds include N-ethylene maleimide)', m-phenylene dimaleimide, 0-phenylene dimaleimide, hexamethylene mareimide, ethylene dimaleimide and dimethylformamaleimide.

Examples of thiol compounds include 1-decanethiol, dimercazotodecane, dipentene dimercaptan, α
, α'-dimercazotope-p-xylene and trimethylolpro-ξ-trithioglycolate.

The amount of accelerator used is from 0.05 to 100 parts by weight of polymer.
The amount is 10 parts by weight, preferably 0.1 to 5 parts by weight.

It is preferable that the temperature of the compound during electron beam irradiation does not exceed the melting point of the resinous polybutadiene used, and it is usually preferable to vulcanize at a temperature of 90° C. or lower. It is particularly preferable to vulcanize at 60°C or lower.

Further, if necessary, a low temperature vulcanization method and an electron beam crosslinking method can be used in combination.

The present invention will be described below with reference to Examples, but the present invention is not limited to these Examples.

Examples 1 to 4 and Comparative Examples 1 to 5 The compositions shown in Table 1 were mixed in a rotor 16 at a temperature of 100 using a silabender mixer (Silabender is a registered trademark).
Operated on Orpm and mixed for 5 minutes. Next, the blend was press-molded at 140°C into a sheet with a thickness of 2 mm. The obtained compound sheet is immersed in the solution containing the vulcanization accelerator prepared earlier (a 5-polymer aqueous solution of pyrolysine penta-methylene-dithiocarnomate) at a liquid temperature of 40°C for 24 hours. . After immersion, the blending sort continues at approximately 40°C.
After aging for 48 hours, the physical properties were evaluated.

The physical property evaluation results are shown in Table 2. The polymer used in Examples 1 to 4 and Comparative Examples 1 to 4 was transbo IJ 7'tadiene, which was prepared by polymerization using a homogeneous composite catalyst consisting of barium tunonylphenoxide, butyllithium, dibutylmagnesium, and triethylaluminum. It is something. The polymer used in Comparative Example 5 was transpolyisozolene (commercial product TP301).

Comparative Example 1 has a transformer bond ratio, Comparative Example 2 Jakuyo and Comparative Example 3
is different from the present invention in terms of weight average molecular weight and Comparative Example 4 in terms of molecular weight distribution. As is clear from Table 2, the golf ball cover material of the present invention has a hard JIS-
D) was 45 or more, the Dunlop rebound was 60% or more, and the DuPont Dart impact strength was 35 or higher, indicating an excellent balance of hardness, rebound, and impact strength.

Table 1 Polymer ioo parts by weight Titanium dioxide 10 parts by weight Zinc white 5 parts by weight Sulfur 1 part by weight Example 5 and Comparative Example 6 When the compositions shown in Table 3 were irradiated in the same manner as in Examples 1 to 4, the results were as follows: Crosslinked.

Table 4 shows the results of physical property evaluation using the obtained crosslinked sheet. The polymer used in Example 5 was made using transpolybuta, citric acid, and the same method as Examples 1 to 4 and Comparative Examples 1 to 4. The polymer used in Comparative Example 6 was transpolyisoprene (TP-301).

As is clear from the physical property evaluation results, even in the crosslinked product obtained by electron beam crosslinking, the golf ball cover material of the present invention sufficiently exhibited its characteristics, such as excellent rebound resilience and impact strength.

*1) Electron beam irradiation device (manufactured by Nissin Electric Co., Ltd.) Accelerating voltage: 500 KV Tube current: 25 mA Table 3 Polymer: 100 weight/Setting part: Titanium oxide: 10 parts by weight

Claims (1)

[Claims] (1) 85% or more of trans bonds, weight average molecular weight (@M
w@) 30,000 to 300,000, molecular weight distribution (@Mw@/@Mn@
) A golf ball cover material obtained by low-temperature vulcanization or electron beam crosslinking of a diene polymer containing at least 30% of resinous transpolybutadiene of 1.2 to 5.0.