JPS5929267B2 - solid golf ball - Google Patents

Description

[Detailed description of the invention] The present invention relates to improvements in solid golf balls.

Solid golf poles are generally advantageous in terms of cost because they can be integrally molded, but they are inferior to thread-wound golf balls in terms of repulsion characteristics, spin performance, feel (hit feel), and the like. In particular, repulsion characteristics have a large effect on the initial velocity of the ball, and are therefore an important factor that influences flight distance. Solid golf balls, which have traditionally been commonly used as having relatively good repulsion properties, contain salt-based zinc methacrylate (BZM) as a co-crosslinking agent in addition to inert fillers and organic peroxides in the base rubber. It is obtained by heating and curing the blended composition.

By pre-heating BZM, the present inventors have discovered that a solid golf pole can be obtained which has less energy loss than conventional solid golf poles and also has high repulsion comparable to that of thread-wound golf balls. The present invention was completed by fully clarifying the above. That is, the present invention is based on the base rubber 10.
0 parts by weight, 10 to 60 parts by weight of basic zinc methacrylate preheated at 150 to 200°C, and 20 parts by weight of inert filler.
The present invention relates to a solid golf pole obtained by heat-curing and molding a composition consisting of ~80 parts by weight and 0.05 to 5.0 parts by weight of an organic peroxide.

A feature of the present invention is that BZM is preheated as described above.

BZM usually contains zinc oxide and methacrylic acid in a ratio of about 1 to 1.5:
The compound obtained by reacting at a molar ratio of 1 to 1 gives a weight loss curve 1 and a differential thermal analysis curve 2 as shown in FIG. On the other hand, when measuring the change in moisture content due to heating, it is approximately 0 at 130℃.
Since water content of approximately 4.5% by weight was detected at 0.03% by weight and at 180°C, it is thought that the weight change around 150°C in Fig. 1 is due to the desorption of crystal water. The change in crystal structure of BZM due to separation is also supported by the X-ray diffraction pattern shown in FIG. 2), and a change of about 20 OOC or more clearly indicates decomposition of BZM. B
Even if ZM is pretreated at a temperature below 150°C (Cl), the effect of the present invention cannot be sufficiently obtained, and if ZM is pretreated at a temperature above 200OC, it does not act as a co-crosslinking agent. From such a thing,
The pretreatment concentration of BZM in the present invention is 150 to 200°C
Deφ. The pretreatment time is usually 1 to 3 hours.

The BZM thus obtained is blended with a base rubber, an inert filler and an organic peroxide and heated to a predetermined temperature, e.g.
A solid golf ball is formed by integral molding in a p-type mold at 0-160°C.

The amount of BZM that has been preheated is usually 10 to 60 parts by weight, preferably 40 to 60 parts by weight, based on 100 parts by weight of the base rubber.
If the amount is less than this, the desired hardness will not be obtained, and if it is too much, the hardness will be too high and the initial speed of the ball will be low.

As the base rubber, suitable natural rubber and/or synthetic rubber that has been conventionally used in solid golf balls can be used, but in the present invention, 1,4-polybutadiene having at least 40% or more cis structure is used. It is particularly preferred that natural rubber, polyisoprene rubber, styrene-butadiene rubber, etc. may be blended with the polybutadiene as desired. Zn as an inert filler
O. Examples include BaSO4, SiO2, CacO3, ZnCOs, etc., but ZnO is common and is used as base rubber 1.
20 to 80 parts by weight per 00 parts by weight.

As the organic peroxide, diwalnut peroxide, t-butyl peroxybenzoate, etc. may be used in an amount of 0 per 100 parts by weight of the base rubber.

Add 5 to 5.0 parts by weight.

The solid golf ball according to the present invention has repulsion characteristics comparable to those of thread-wound golf balls while maintaining durability equivalent to conventional golf balls.

The present invention will be explained below using Examples and Comparative Examples.
EXAMPLES AND COMPARATIVE EXAMPLES Three types of compositions having the compounding ratios shown in Table 1 were prepared using a roll kneader.

1) Polybutanine made by Japan Synthetic Rubber Co., Ltd. 2) 13
BZM treated at 0°C for 5 hours 3) BZM treated at 160°C for 3 hours The obtained compositions 1, 2 and 3 were heated at 150°C in a predetermined mold.
Molded solid golf balls I, ■, and ■, each having a diameter of 1.62 inches, were prepared by pressure molding for 30 minutes.

Golf balls I, ■, and ■ were tested for compression, initial velocity, and durability.

The results are shown in Table-2. Reference Example 'Two types of compositions having the compounding ratios shown in Table 3 were prepared by roll kneading.

The thickness obtained by pressing the above composition at 160°C for 30 minutes was about 0.

6. 4mm x 40cm x 0 from a fake slab.

A sample piece with a size of 6 mm was cut out.

The loss tangent Tan δ of the sample piece was measured at 35° C. and 10 Hz using a viscoelastic spectrometer (manufactured by Iwamoto Seisakusho).

The measurement results are shown in Figure 3.

[Brief explanation of drawings]

Figure 1 shows the weight loss curve and differential thermal analysis curve of BZM (carrier gas NiN23O/Min, sensitivity: ±1
~, heating rate: 10°C/Min, Chart Speedni 1
0 m [minutes In) Thermo Katsupuruni CA, DTG Rangeini I~Amln). FIG. 2 represents the BZMO x-ray diffraction pattern. Figure 3 shows the dynamic strain (horizontal axis: %) and loss tangent (vertical axis: T) of the elastomer.
and (δ)5. 1 is a weight loss curve, 2 is a differential thermal analysis curve, 3 is an X-ray diffraction pattern of heat-treated BZM (7), 4 is an X-ray diffraction pattern of untreated BZM, and 5 is the dynamic behavior of an elastomer using untreated BZM as a co-crosslinking agent. 6 shows the relationship between dynamic strain and loss tangent of an elastomer using heat-pretreated BZM as a co-crosslinking agent.

Claims (1)

[Scope of Claims] 1. 100 parts by weight of base rubber, 10 to 60 parts by weight of basic zinc methacrylate preheated at 150 to 200°C,
20-80 parts by weight of inert filler and 0 organic peroxides
．． A solid golf ball obtained by thermosetting and molding a composition comprising 5 to 5.0 parts by weight. 2. The solid golf ball according to item 1, wherein the base rubber is 1,4-polybutadiene having at least 40% cis structure. 3. The solid golf ball of item 1, wherein the inert filler is zinc oxide. 4 The first organic peroxide is dicumyl peroxide
The solid golf ball described in Section 1.