JPS6182768A - 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 [Field of Industrial Application] The present invention relates to golf balls. More specifically, the present invention relates to a golf ball with improved repulsion performance by using a modified ionomer in the cover.

[Conventional technology]

Traditionally, golf ball covers have been made of ionomers with a 1fr.
It has been popular because of its excellent J properties, cut resistance, and flight performance.

This ionomer is an ionic ethylene copolymer,
Its components are a copolymer consisting of three components: ethylene, a metal salt of an unsaturated carboxylic acid, and an unsaturated carboxylic acid, or a four-component component: ethylene, a metal salt of an unsaturated carboxylic acid, an unsaturated carboxylic acid, and an unsaturated carboxylic acid ester. Among the above components, the unsaturated carboxylic acid is preferably a monobasic acid such as acrylic acid or methacrylic acid, and may also be a dibasic acid such as maleic acid or fumaric acid. The acid content is expressed as the weight percent of the unsaturated carboxylic acid, regardless of whether it is neutralized or not, and usually this acid content is 6% by weight.
It is said that the amount of electricity is ~20%. The unsaturated carboxylic acid metal salt is a metal salt of the above-mentioned unsaturated carboxylic acid, and its metal species include monovalent metals such as sodium and potassium, and 21i [[i gold muds such as zinc, magnesium, and calcium]. The degree of neutralization by metal ions is generally 20
It is said to be ~80%. The unsaturated carboxylic acid ester is an alkyl ester of the above-mentioned unsaturated carboxylic acid, and the alkyl group thereof has 1 to 10 carbon atoms, and is usually methyl, ethyl, propyl, or the like.

As above -? There are various types of iono-7-, and it is said that there are many kinds of neutralizing metal species as mentioned above, but the ones that are actually commercially available are of the sodium ion neutralizing type. There are only ionomers and ionomers neutralized with zinc ions; ionomers neutralized with other metal ions are not commercially available.

Among the above-mentioned commercially available ionomers, those that improve the repulsion performance of golf balls include Surlyn Norse 1605 from Devon and Hymilan Norse 1605 from Mitsui Polychemicals.
(N a ), 1605/1707 for blend system
(Na/Na), 1605/1706 (Na/Zn
). Note that Na in parentheses indicates a sodium ion neutralization type, and Zn indicates a zinc ion neutralization type.

[Problem to be solved by the invention] The above ionomer 1605.1605/1707.1
605/1706 has high repulsion performance and is currently the main material for covers, but golf pole users are starting to think about how to extend the flight distance, and are looking to make 11 sheets with even higher repulsion properties. There is a strong desire for a golf ball with even higher resistance to 18 performance.

However, as long as a commercially available ionomer is used for the cover, it will not be possible to produce a higher anti-Iθ performance than the above-mentioned compound system.

[Means for solving problems]

In view of the above circumstances, the inventors of the present invention have conducted various studies, and have modified the ionomer by partially neutralizing the free carboxylic acid in the ionomer with alkali metal ions, and used it as the main material for golf ball covers. It was discovered that when used as a material, a golf ball with high repulsion performance can be obtained, leading to the completion of the present invention.

Examples of the alkali gold mud ions used for neutralization include metal ions such as lithium, sodium, potassium, cenium, and rubinium.When modifying the ionomer, these alkali metal ions can be converted into hydroxides, acetates, oxides, or the like. used in the form of a mixture of However, when modifying the ionomer, alkali metal ions that are different from the metal ions used to neutralize the ionomer are used in part.

To modify an ionomer, for example, the ionomer is wound around a roll, the roll temperature is adjusted to 130 to 150°C, and a predetermined amount of the above-mentioned alkali metal hydroxide, acetate, oxide, etc. is added to the ionomer in that state and kneaded. The reaction is carried out by raising the resin temperature to about 150 to 190° C. and reacting for 20 to 60 minutes. Modification can also be carried out using an extruder.

Various reasons have been postulated as to why the anti-1a performance is improved by partially neutralizing free carboxylic acid with alkali metal ions as described above, but there is currently no clear explanation. However, as shown in Example 1 below, a significant improvement in anti-1a performance was observed.

The degree of neutralization of free carboxylic acid with alkali metal ions is preferably 7 to 30%. This is because if the degree of neutralization is less than 7%, there is little effect on improving the anti-1a performance, and if the degree of neutralization exceeds 30%, the flow becomes poor and formability decreases, and the strength of the joint surface with the core decreases. This is because it invites (causes)

The cover material is mainly made of the ionomer modified as described above, and if necessary, pigments such as titanium dioxide, etc.
It is cleaved by appropriately adding additives such as dyes, anti-aging agents, and layering agents, and then combining them.

This cover can be used to cover either a solid golf ball core or a thread-wound golf ball core. The cover can be applied to the core by either compression molding or compression molding.
The thickness of the cover is between 1.3 and 2.5 m.

[Implemented]

Next, the present invention will be explained in more detail by giving Examples.

Example 1 As an ionomer, Himilan+605 (trade name, Mikata Borite\Calshashi, used carbonic acid, methacrylic acid,
Acid content 15% by weight, degree of neutralization of carboxylic acid by sodium ions 29%) was wound around a roll, the roll temperature was adjusted to 130°C, and lithium hydroxide hydrate was added to the ionomer. It was added at a ratio of 1.08 parts to 100 parts (by weight, the same applies hereinafter) of the ionomer, and while kneading, the resin temperature was raised to 170° C. and reacted for 30 minutes. The degree of neutralization of free carboxylic acid by lithium ions was 15%.

Next, apply titanium dioxide to the ionomer modified as above on a roll per 100 parts of the ionomer! 5
A half nonyl for golf ball covers was prepared using the obtained 1-component mixture.

Use a pair of the above barfuner and directly + 37 tav
The ball was placed over a solid core of 2.5 mm and molded in a press at 160° C. for 2.5 minutes to form a two-piece golf ball with a diameter of 41.2+u+ and a thickness of 1.

The resulting two-piece solid golf ball was examined for its weight, combre noyon, anti-18 coefficient, cut resistance, and impact resistance.The results are shown in Table 1.The solid core used in the above golf ball was as follows: Acrylic acid! [18] 35 parts of lead, 53 parts of zinc oxide, and 1 part of Tsucumyl peroxide were added to 100 parts of Meth-14-polybutadiene, kneaded, and opened. The rubber composition was molded at 150°C for 20 minutes. This is what I got.

Example 2 Hymilan 160 was used as the ionomer in the same manner as in Example 1.
5, wrap it around a roll and set the roll temperature to 13
The temperature was adjusted to 0°C, and cesium acetate was added to the above ionomer at a ratio of 495 parts to 100 parts of the ionomer, and the resin temperature was raised to 170°C while kneading. ? L
and allowed to react for 30 minutes. The degree of neutralization of free carboxylic acid by cenium ions was 15%.

A two-piece solid golf pole was prepared in the same manner as in Example 1, except that the ionomer modified as described above was used as the main cover material, and the physical properties of the obtained golf ball were determined in the same manner as in Example 1. The result is the first
Shown in the table.

Example 3 Two types of ionomers, i.e. Hymilan 16 as described above.
05 and Himiran 1706 (manufactured by Mikata Polychemical Co., Ltd.,
Carboxylic acid used: methacrylic acid, acid content: 15% by weight
, neutralization degree of carboxylic acid by zinc ions: 58%) was wound around a roll at a weight ratio of 50 + 50, the roll temperature was adjusted to 130°C, and cenium acetate was added to the above ionomer based on 100 parts of the ionomer. :! , 1
1 a:':++ i'i! In addition, 11 kneaded resins are added! , temperature to 170°C for 5 yen? and reacted for 30 minutes. The degree of neutralization of free carboxylic acid by cenium ions was 10%.

A two-piece solid golf pole was prepared in the same manner as in Example 1, except that an ionomer modified as described in Section 2 was used as the main material, and the physical properties of the obtained golf ball were measured in the same manner as in Example 1. The results are shown in Table 1.

Comparative Example 1 A two-piece solid golf pole similar to that of Example 13111 was produced except that Himilan 1605 was used as it was without modification as the cover main (O), and the obtained golf ball was tested (the same physical properties as in the first example were obtained). It was measured.

The results are shown in Table 1.

Comparative Example 2 Himilan 1605 and Himilan 17 as main cover materials
A two-piece Norinodo golf ball was prepared in the same manner as in Example 1, except that the mixture with 06 in a weight ratio of 50 + 50 was used without modification, and the same physical properties as in Example 1 were obtained for the iM golf ball. I ran δ11. The results are shown in Table 1.

As shown in Table 1, the golf balls of Examples 1 to 3 of the present invention in which the modified ionomer was used for the cover are different from those in Comparative Examples 1 to 3 in which the ionomer was used as is without modification.
The restitution coefficient was higher than that of the golf ball, and both the cut resistance and impact resistance were good, and no decrease in cut resistance or impact resistance was observed due to the modification.

〔Effect of the invention〕

As explained below, according to the present invention, a golf ball with excellent repulsion performance can be produced by partially neutralizing the free carboxylic acid in the ionomer with alkali metal ions and using it as the main cover material. I was able to get it.

Claims (1)

[Claims] (1) A golf ball having a core and a cover covering the core, characterized in that the cover is made of an ionomer in which free carboxylic acid in the ionomer is partially neutralized with alkali metal ions. .