JPS5957675A - Two-piece solid golf ball - 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] TECHNICAL FIELD The present invention relates to a two-piece ball.

A two-piece solid golf ball, which was developed to improve the poor durability of thread-wound golf balls, is composed of an integrally molded solid core and a cover covering the solid core. The material used for the cover is an ionomer resin, which is made by chemically bonding metal ions to an ethylene copolymer, because it has excellent mechanical strength, particularly good ability to cut one side when struck, and moderate elasticity. It is being used in place of natural rubber, etc.

However, there is still room for improvement in the conventional saw-piece solid golf balls of this type in terms of repulsion (C), ball initial velocity at impact), write-in performance, and especially low-temperature durability (OJ). The gist is that a composition containing 100 parts by weight of base rubber, 10 to 60 parts by weight of a metal salt of an unsaturated fatty acid, 40 to 70 parts by weight of zinc oxide, and 1 to 5 parts by weight of a crosslinking agent is heated. The solid core obtained by hardening has a Shore D hardness of 65 or higher, a tensile strength of 250 to 300 kq/C1n, and a embrittlement temperature.
100--110℃, MI (Melt Inde
x ) = Q.

7-2.0, ionomer resin 40-45 with a melting point of 88°C
Part by weight, Hardness D: 65 or more, Tensile strength: 275-3
20 kq10r+ and embrittlement temperature -100 to -1]O
°C, MI = 2.3-3.0, 40-45 parts by weight of ionomer resin with melting point 90 °C, Shore 1) Hardness 60-64,
Tensile strength 200-230 kq/an and embrittlement temperature -
70 to -80°C, M I == 8 to 12, melting yore D hardness 60 to 64. Tensile strength 190-220 kQ/
cm and embrittlement temperature -75 to -85°C, MI-4,s
-'s, o, ionomer resin 5 to 1 with melting point of 94°C
This consists of a two-upine solid Corfu ball that is covered with a cover whose main material is a 0-type opening.

The base rubber used in the present invention is polybutadiene com,
Examples include styrene butadiene com, natural comb, high styrene resin, etc. Polybutadiene com, among others Nnu 1,
4-Hoributashiencom is preferred.

Examples of the metal salts of unsaturated fatty acids used in the invention include unsaturated fatty acids having 3 to 8 atom atoms, such as zinc salts of acrylic acid, methacrylic acid, magne/rum salts, etc., but especially zinc acrylate. and/or zinc methacrylate are preferred.

The metal salt of unsaturated fatty acid is used in an amount of 10 to 60 parts by weight based on 100 parts by weight of the base comb. If the amount of the metal or salt is less than 10 parts by weight, sufficient hardness will not be obtained and the initial velocity of the ball at impact will be low; if it is more than 60 parts by weight, the ball will become hard and bunch, reducing the initial velocity. do.

Zinc oxide is used as a weight adjuster, and its amount is usually 40 to 70 parts by weight per 100 parts by weight of the rubber material.

Other conventional fillers, such as barium sulfate, calcium FA acid, silica, etc., may be used as appropriate weight adjusters.

Examples of crosslinking agents used to obtain the optimum hardness for the solid core include peroxides such as dicumyl peroxide OJ and azo compounds such as 7zobisisobutylnitrile, with dicumyl peroxide being particularly preferred. .

The amount of crosslinking agent is usually 1 part by weight per 100 parts by weight of the base rubber.
~5 parts by weight, and when using 0J crosslinking agent outside this range, the core of optimum hardness is KR yellow (t).

The core composition obtained by blending the two components is wet-kneaded using a conventional kneading machine, such as a Banbury mixer or a roll, and then press-molded at about 140 to 70°C by a conventional method to form a standard. θ] One-piece solid core.

The cover covering the integrally molded solid core is mainly made of an ionomer resin, and may contain an appropriate inorganic filler such as titanium dioxide, zinc oxide, etc. for the purpose of coloring, if necessary.

The ionomer resin used in the invention is a thermoplastic resin, preferably a monoolefin, in which a cross-metallic bond is added to a polymer of a monoolefin and at least one selected from the group consisting of unsaturated mono- or dicarboxylic acids and esters thereof. and at least one polymer selected from the group consisting of unsaturated mono- or dicarboxylic acids having 3 to 8 carbon atoms and their A thermoplastic resin containing cross-metallic bonding.

The following four types of mixed tree resin are selected from the following.

That is, Shore D hardness is 65 or more, tensile strength is 250-30
0 kg/cm and embrittlement temperature -100~-]]0℃
, M I = 0.7-2,0, an ionomer resin having the characteristics of a melting point of 88°C (hereinafter referred to as ionomer resin I), a 40-45 overlapping part, a Shore D hardness of 65 or more, a tensile strength of 275-320 kglorr, and Brittle temperature -
100 to -110°C, MI: 2.3 to 3.3, melting point 90°C Ionomer resin C (hereinafter referred to as ionomer resin ■) 40 to 45 parts by weight, Shore D
Hardness 60-64, tensile strength 200-230 kq/cm
and embrittlement temperature -70 to -80°C, Ml -8 to 12,
Ionomer resin C or below, ionomer resin ■ having the characteristics of a melting point of 96°C, 5 to 10 parts by weight, Shore D hardness 60 to 64, tensile strength 190 to 220 kq/
α and embrittlement temperature -75, -85°C, MI==4.5
It is a mixed resin consisting of 5 to 10 parts by weight of ionomer resin (hereinafter referred to as ionomer resin (hereinafter referred to as ionomer resin)) having the characteristics of ionomer resin C and melting point of 8.0°C and 94°C.

When the blending proportions of ionomer resin I=II, ■ and ■ are out of the upper rudder range, the intended object of the present invention is achieved. If the amount of ionomer resin (2) is less than 40 parts by weight, the initial velocity of the ball will be lowered and the durability will be lowered, and if it is more than 45 parts by weight, the low temperature durability will be deteriorated. Azuonomer resin ■ is 40
If the amount is less than 1 part by weight, the moldability will deteriorate and the fusion strength will decrease. If the amount of the ionomer resin (2) is less than 5 parts by weight, the fusing strength will be reduced, and if it is more than 10 parts by weight, the initial velocity of the ball will be reduced. If the amount of the ionomer resin (2) is less than 5 parts by weight, the moldability will deteriorate, and if it is more than 10 parts by weight, the initial velocity of the pole will decrease.

The method of covering the solid core with the cover is not particularly limited, but usually the solid core is wrapped with two covers that have been previously formed into a hemispherical shell shape, and the solid core is press-molded at about 170° C. for 2 minutes. Alternatively, the cover composition may be injection molded to enclose the solid core.

The Sou-Piece solid golf ball obtained as described above has improved repulsion (initial velocity dust) and durability, especially low-temperature durability and poor feel when hitting, which were insufficient in conventional products of the same type. This is an improved golf ball.

Hereinafter, the present invention will be explained by examples.

Example 1 and Comparative Examples 1 to 6 The core composition according to the formulation shown in Table 1 was placed in a mold.
Pressure molded at 50° for 30 minutes to create a diameter of 37°1 m no.0
Manufactured by Nokoa.

The obtained core was coated with a coating according to the formulation shown in Table 1 in a conventional manner to produce a Numol@I is two pine golf ball.

Table 1 shows the physical properties of the obtained ball.

Table-1 1″ Dupont Surlyn 1605 (Shore D hardness 67,
Tensile strength 296 kglorr, embrittlement temperature -106℃
1. MI=2.8, melting point 90°C) DuPont ZARLIN 1.706 (Shore D hardness 66, tensile strength 275
kqlolt, embrittlement temperature -105°C, MI=0.
7. Melting point 88℃) 31 Surlyn 1555 manufactured by Typhon
(Nyoar D hardness 62, tensile strength 214 kqlo)
! , embrittlement temperature -75°C, M1=IQ, melting point 96°C
) 4' DuPont ZARLIN 1557 (/core 1) Hardness 63, Tensile strength 204 kQ/C〃t, Brittleness 1FI
A degree -80°C, MI=5.0, melting point 94°C) Measured using a swing robot manufactured by Tsuruichi Temper Co., Ltd. (Head Nupedo 451±Q, 3 m 7 seconds, ball temperature 25°C).

6. Relative value when the number of impact resistance of the ball according to Example 1 is set to 100.

71 Relative value when the number of impact resistance of the ball according to Example 1 is set to 100.

Claims (1)

[Claims] (1) 100 parts by weight of base rubber, 10 parts by weight of metal salt of unsaturated fatty acid
A solid core obtained by heating and curing a composition containing ~60 parts by weight, 40 to 70 parts by weight of zinc oxide, and 1 to 5 parts by weight of the crosslinked side has a Shore D hardness of 65 or more and a tensile strength of 25.
0~300kg/cnort2 and embrittlement temperature -100~
-110°C, MI-07 to 2.0, 40 to 45 parts by weight of ionomer resin with melting point of about 88°C, Shore D hardness of 65 or more, tensile strength of 275 to 320 kq/cnr, and embrittlement temperature of -100 to -1]0 °C, MI: 2.3-3.
3. Ionomer cedar fat with melting point of 90°C 40-45 parts by weight, Shore D hardness 60-64, tensile strength 200-230
kglon and embrittlement temperature -70~-80℃, MI
= 3-12, ionomer resin with melting point of 96°C 5-1
0 parts by weight and Shore D hardness 60-64, tensile strength 1
90-2201 cq/cm and embrittlement temperature -75--
A two-piece solid golf ball coated with a cover whose main material is 5 to 10 parts by weight of an ionomer resin having a temperature of 85°C, M 1-4.5 to 8.0, and a melting point of 94°C. 2. The solid golf ball according to item 1, wherein the base material is cis-1,4-polybutadiene rubber. 3. The solid golf ball according to item 1, wherein the metal salt of unsaturated fatty acid is zinc acrylate and/or zinc methacrylate. 4. The solid golf ball according to item 1, wherein the cross-linking agent is dicumyl peroxide.