JP3516134B2 - Solid golf ball - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solid golf ball having a multilayer structure in which a cover having at least four layers is formed on a core.

[0002]

2. Description of the Related Art Conventionally, as a structure of a solid golf ball, a solid golf ball having a multilayer structure in which a core and a cover are multi-layered has been proposed (JP-A-8-336617 and 8-8). 336618
No. 9, No. 9-56848, No. 9-299510, No. 1
1-417, 11-4916, etc.).

The purpose of multilayering a solid golf ball is to
On the one hand, it gives the same feeling as a thread-wound golf ball, and on the other hand, it aims to improve the flight distance. Generally, if the feeling is emphasized, the flight distance is not satisfied, and if the flight distance is satisfied, the feeling is reduced In addition, many of the conventional proposals are mainly aimed at players with a high head speed, and thus give a sufficient flight distance even when shot at a low head speed and have a good feeling. Further development of golf balls is desired.

The present invention has been made in view of the above circumstances.
It is an object of the present invention to provide a multi-layer solid golf ball which gives a sufficient flight distance even when shot at a low head speed as well as at a high head speed and has a good feel.

[0005]

Means for Solving the Problems and Embodiments of the Invention In order to achieve the above object, the present invention provides the following golf balls. A multi-layer golf ball comprising a core and a four-layer cover, wherein the Shore D hardness of the first-layer cover covering the core is 6
0 or less, the Shore D hardness of the second layer cover that covers the first layer cover is 45 or more, and the Shore D hardness of the third layer cover that covers the second layer cover is 45 or less. It is made harder than the first layer cover,
The fourth layer cover covering the layer cover has a Shore D hardness of 58.
.About.65 and the fourth layer cover is formed to have a thickness of 1.5 to 2.0 mm. The Shore D hardness of each of the first layer cover and the third layer cover is 10
~ 45, and the Shore D hardness of the second layer cover is 45-7.
The solid golf ball of claim 1, wherein the solid golf ball is 0. The solid golf ball according to claim 1 or 2, wherein the core has a diameter of 26 to 35 mm, and the Shore D hardness of the core surface is 40 or more. 4. The first layer cover and the third layer cover are respectively made of polyester resin,
The solid golf ball according to claim 1, wherein the solid golf ball is formed of one kind or two or more kinds of a polyurethane resin and a thermoplastic polyamide-based elastomer. 5. The solid golf ball of claim 1, wherein the fourth layer cover is made of an ionomer resin.

That is, the present inventor has made earnest studies in view of the above-mentioned object, and as a result, the sandwich structure of the hard and soft covers can be made into two layers by forming the above-mentioned four-layer cover. Since the sandwiched soft cover layer is constrained at the boundary with the hard cover layer, it shows the behavior of a hard material even though it is a soft material. Therefore, since the amount of deformation is optimized, it is a soft ball. , You can get high repulsion ball,
On the other hand, by using such a two-layer soft cover, it has been found that a good feeling can be obtained and the spin characteristics can be optimized, and the present invention has been completed.

The present invention will be described in more detail below.
The golf ball of the present invention has at least one or more cores and a four-layer cover. As shown in FIG. 1, a first-layer cover 2 is formed so as to cover the core 1, and then a second-layer cover is formed. The layer cover 3, the third layer cover 4, and the fourth layer cover 5 may be covered and formed.

The core has a diameter of 26 mm or more, particularly 29 mm or more, and 35 mm or less, especially 33.5.
mm can be formed.

The core can be formed of a rubber composition, a thermoplastic resin or a mixture thereof. As the rubber composition, a known composition can be used,
It is preferable to use polybutadiene as the base material.
This polybutadiene has a cis structure of at least 4
Preferable is 1,4-cis polybutadiene having 0% or more. If desired, natural rubber, polyisoprene rubber, styrene-butadiene rubber, etc. may be blended with the polybutadiene in the base rubber. By increasing the rubber component, the resilience of the golf ball can be improved.

The above rubber composition may contain, as a cross-linking agent, a zinc salt of an unsaturated fatty acid such as zinc methacrylate or zinc acrylate, a magnesium salt, or an ester compound such as trimethyl propane methacrylate. Zinc may be preferably used. The compounding amount of these crosslinking agents is preferably 10 parts by weight or more and 30 parts by weight or less with respect to 100 parts by weight of the base rubber.

A vulcanizing agent is usually blended in the rubber composition, and peroxide (organic peroxide) is preferably used as the vulcanizing agent. Examples of such peroxides include commercially available products, such as Perkmill D and Perhexa 3M (manufactured by NOF Corporation).
The compounding amount can be 0.6 parts by weight or more and 2 parts by weight or less with respect to 100 parts by weight of the base rubber.

Furthermore, if necessary, zinc oxide, barium sulfate or the like can be blended as an antiaging agent or a filler for adjusting the specific gravity.

The surface of the core has a Shore D hardness of 4
0 or more, more preferably 45 or more, further preferably 49
It is preferably at least 65, more preferably at most 63, and further preferably harder than the first layer cover described later.

In this case, the core can be formed in a multi-layered structure having two or more layers. For example, the innermost core is formed of a rubber composition, and the outer core is formed of a thermoplastic resin such as an ionomer resin to cover the innermost core. The outer core can be formed into a shape having the above-mentioned Shore D hardness.

Each of the first to fourth layer covers is preferably formed of a thermoplastic resin, but may be formed of a material having rubber as a base material. Examples of the thermoplastic resin include polyurethane resin (polyurethane thermoplastic elastomer), polyester resin (polyester thermoplastic elastomer), polyamide thermoplastic elastomer,
Examples thereof include ionomer resins, and commercially available products include Pandex (polyurethane thermoplastic elastomer manufactured by Dainippon Ink and Chemicals, Inc.), Hytrel (polyester thermoplastic elastomer manufactured by Toray DuPont), and Surlyn (manufactured by DuPont). Ionomer resin), high milan (ionomeric resin manufactured by Mitsui DuPont), rilsan (polyamide resin manufactured by Toray), pepax (thermoplastic polyamide elastomer manufactured by Toray), and the like can be preferably used.

Here, the first layer cover is formed to have a Shore D hardness of 60 or less, preferably 55 or less, more preferably 45 or less. In this case, the lower limit is 10 Shore D hardness.
As described above, it is more preferably 20 or more, and further preferably 25 or more. If the Shore D hardness is too high,
The disadvantage is that a soft feeling cannot be obtained.

This first layer cover is made of polyester resin,
It is preferably formed of a polyurethane resin, a thermoplastic polyamide-based elastomer, or a mixture thereof. Moreover, you may mix an ionomer resin as needed.

The thickness of the first layer cover is 0.5 mm or more,
More preferably 0.8 mm or more, still more preferably 1.0
It is preferable that the thickness is not less than mm and not more than 4.0 mm, more preferably not more than 3.0 mm, and further preferably not more than 2.5 mm.

Next, the second layer cover has a Shore D hardness of 4
It is formed to be 5 or more, preferably 55 or more, more preferably 60 or more, and harder than the first layer cover. When the second layer cover is softer than the first layer cover or softer than the above value, the effect of restraining the first layer cover cannot be sufficiently obtained, and the resilience is lowered. The second
The upper limit of Shore D hardness of the layer cover is preferably 70 or less, and particularly preferably 65 or less. The second layer cover may be made of any thermoplastic resin that gives the above hardness, but it is preferable to use an ionomer resin, particularly a high acid ionomer resin.

The thickness of the second layer cover is 0.5 mm or more,
More preferably 0.8 mm or more, still more preferably 1.0
It is preferable that the thickness is not less than mm and not more than 4.0 mm, more preferably not more than 3.0 mm, and further preferably not more than 2.5 mm.

The third layer cover is formed to have a Shore D hardness of 45 or less, particularly 40 or less. In this case, the lower limit thereof is preferably a Shore D hardness of 10 or more, more preferably 20 or more, further preferably 25 or more, and it is formed softer than the second layer cover and softer than the fourth layer cover described later. To do. If the Shore D hardness of the third layer cover is larger than 45, there is a disadvantage that a soft feeling cannot be obtained.

Like the first layer cover, the third layer cover is also preferably made of polyester resin, polyurethane resin, polyamide thermoplastic elastomer, or a mixture thereof. Moreover, you may mix an ionomer resin as needed.

The thickness of the third layer cover is 0.5 mm or more,
More preferably 0.8 mm or more, still more preferably 1.0
It is preferable that the thickness is not less than mm and not more than 4.0 mm, more preferably not more than 3.0 mm, and further preferably not more than 2.5 mm.

The fourth layer cover needs to be formed harder than the third layer cover, and if the fourth layer cover is softer than the third layer cover, the object of the present invention cannot be achieved. in this case,
The Shore D hardness of the fourth layer cover is 58 or more, and 6
It is 8 or less, preferably 65 or less.

The material of the fourth layer cover is not particularly limited, but it is preferably formed of an ionomer resin.

The thickness of the fourth layer cover is 1.5 mm or more and 2.0 mm or less.

In the present invention, the hardness distributions of the core and the first to fourth layer covers are as described above. Among these, when the second layer cover has the maximum hardness, the controllability and feeling are better. become.

The first to fourth layer covers are preferably formed of a thermoplastic resin as described above, but an inorganic filler may be added to the cover for the purpose of adjusting the specific gravity, or any other suitable material. Additives are optional.

The golf ball of the present invention, like a normal golf ball, has a composition of 300 to 600 according to a known arrangement mode.
Individual dimples can be formed.

The golf ball of the present invention has a diameter and a weight of 42.65 mm or more, particularly 42.67 mm or more and 42.75 mm or less, and a weight of 45.93 g or less, according to the Rules of Golf. Especially 45.90g
Below, it can be formed to 45.10 g or more.

[0031]

INDUSTRIAL APPLICABILITY The golf ball of the present invention has good flight distance performance irrespective of high and low head speeds, and can improve the flight distance even when the head speed is low. The ring is good.

[0032]

EXAMPLES The present invention will be specifically described below by showing Examples and Comparative Examples, but the present invention is not limited to the following Examples.

[Examples, Comparative Examples] Rubber formulations shown in Table 1,
The five-piece solid golf ball shown in Table 3 was produced with the resin composition shown in Table 2, and its flight performance and feeling were evaluated by the following methods. The results are shown in Table 3. Flying performance A swing robot was used to hit with a driver at head speeds of 45 m / sec and 35 m / sec, respectively, and the initial velocity, carry, and total flight distance were measured. Feeling The three professional golfers actually hit the ball and evaluated it. ◎: Very good ○: Excellent △: Normal ×: Inferior

[0034]

[Table 1] * Vulcanization conditions Core: 155 ° C, 15 minutes Inner layer / middle layer: 130 ° C, 10 minutes (semi-vulcanized) → 155
℃, 15 minutes (total vulcanization)

[0035]

[Table 2]

[0036]

[Table 3]

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

[Explanation of symbols]

1 core 2 1st layer cover 3 Second layer cover 4 Third layer cover 5 4th layer cover

Continuation of front page (56) Reference JP-A-9-248351 (JP, A) JP-A-11-417 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) A63B 37 / 00

Claims (5)

(57) [Claims] 1. A multi-layer golf ball comprising a core and a four-layer cover, wherein the Shore D hardness of the first-layer cover covering the core is 60 or less, and the shore of the second-layer cover covering the first-layer cover. The D hardness is 45 or more, and the Shore D hardness of the third layer cover that covers the second layer cover is 45 or less. The second layer cover is formed to be harder than the first layer cover, and the third layer cover is covered. The fourth layer cover has a Shore D hardness of 58 to 65 and a fourth layer cover thickness of 1.5 to
A multi-layer solid golf ball, which is formed to have a thickness of 2.0 mm. 2. The Shore D hardness of each of the first layer cover and the third layer cover is 10 to 45, and the Shore D hardness of the second layer cover is
The solid golf ball of claim 1, which has a hardness of 45 to 70. 3. A core having a diameter of 26 to 35 mm and a Shore D hardness of 40 or more on the surface of the core.
The solid golf ball described. 4. The first layer cover and the third layer cover are each formed of one kind or two or more kinds of a polyester resin, a polyurethane resin and a thermoplastic polyamide-based elastomer, respectively. Solid golf ball. 5. The solid golf ball of claim 1, wherein the fourth layer cover is made of an ionomer resin.