JP3533953B2 - Multi-piece 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 multi-piece solid golf ball having at least a three-layer structure including a solid core, an intermediate layer and a cover, which has a soft and good feeling on approach shots and puttings, and a driver. Relates to a multi-piece solid golf ball whose flight distance increases at full shot.

[0002]

2. Description of the Related Art Two-piece solid golf balls, which have been proposed in large numbers, have a trajectory called a so-called stick ball in both driver shots and iron shots, as compared with wound golf balls. It has the advantage of increasing the total flight distance due to the large number of runs due to the structural characteristics that spin is hard to occur.

On the other hand, a two-piece solid golf ball tends to be inferior in controllability as compared with a thread-wound golf ball because it is hard to spin on an iron shot so that it is hard to stop on the green.

On the other hand, a golf ball is required to have a soft hit feeling upon hitting as the flight distance increases, and without it, the commercial value is impaired. In general, the thread-wound golf ball has a structural characteristic that it is softer and has a good feel when compared with the two-piece solid golf ball.

Therefore, in a two-piece solid golf ball consisting of a core and a cover, the ball structure is generally softened in order to achieve a soft feel on impact.

However, such a soft type two-piece solid golf ball generally uses a soft core. However, if the core is made too soft, the resilience is lowered, the flight performance is lowered, and the durability is remarkably increased. There is a problem that not only the excellent flight performance and durability which are the characteristics of the two-piece solid golf ball cannot be obtained but also it becomes difficult to endure the actual use.

Recently, in order to solve such a problem, many three-piece solid golf balls having an intermediate layer provided between a core and a cover have been proposed (Japanese Patent Laid-Open No. 7-2).
4084, JP-A-6-23069, JP-A-4-244174, JP-A-9-10358, JP-A-9-313643).

However, even in these proposals,
When the cover and the intermediate layer are softly formed, the feeling becomes soft, but the flight distance at the time of a full shot with a driver decreases. On the other hand, when trying to obtain a flight distance, the cover and the intermediate layer have to be formed hard, and as a result, the shot feeling during approach shots and putting is reduced, and in any case, solid Golf balls have not yet been obtained, and further improvements have been desired.

The present invention has been made in view of the above circumstances, and in a multi-piece solid golf ball having at least a three-layer structure including a solid core, an intermediate layer and a cover, it is very soft and good at approach shots and putting. An object of the present invention is to provide a multi-piece solid golf ball which has a ring and has excellent flight performance during a full shot with a driver.

[0010]

Means for Solving the Problems and Modes for Carrying Out the Invention As a result of intensive studies for achieving the above-mentioned object, the present inventor has found that at least a multi-layer structure having a solid core, an intermediate layer and a cover is provided. In a piece solid golf ball, by combining a relatively soft formed core, a very soft mid layer, and a relatively hard cover, it has a very soft and good feeling on approach shots and putting, and at the same time with a driver. It was found that a multi-piece solid golf ball having excellent flight performance at the time of full shot can be obtained.

That is, in a multi-piece solid golf ball provided with a solid core, at least one intermediate layer covering the core, and at least one cover covering the intermediate layer, preferably, the solid core is a rubber base material. Is used as the main material, its specific gravity is 1.1 to 1.5, and the amount of deformation when a load of 100 kg is applied to the core is 2.5 m.
m is relatively soft, and the intermediate layer covering the core is a very soft thermoplastic resin having a Shore D hardness of 8 to 35, particularly (A) a thermoplastic polyester-based elastomer and (B) an olefin-based resin. A heating mixture formed by mixing an elastomer and a modified product thereof, and one or more thermoplastic elastomers selected from a styrene block copolymer and a hydrogenated product thereof is used as a main material, or (B ) Component is used as the main material, and the cover for covering this intermediate layer is made of a relatively hard thermoplastic resin, especially a Shore D hardness of 57.
By forming the above ionomer resin as a main material and making the Shore D hardness of this cover higher than the Shore D hardness of the intermediate layer by 25 or more, the above-mentioned synergistically acts to produce approach shots and puttings. Sometimes it has a very soft and good feeling,
The present invention has been completed by finding that an unprecedented multi-piece solid golf ball having excellent flight performance at the time of a full shot with a driver and good durability at continuous hits can be obtained.

Therefore, the present invention provides (1) a multi-core provided with a solid core formed of a rubber composition, at least one intermediate layer covering the core, and at least one cover covering the intermediate layer. In the peace solid golf ball, the intermediate layer contains one or more selected from a thermoplastic polyester elastomer, (B) an olefin elastomer and its modified product, and a styrene block copolymer and its hydrogenated product. While using a heated mixture with a thermoplastic elastomer, the Shore D hardness of the intermediate layer is 8 to 24, and the cover is formed to have a Shore D hardness of 57 or more with a thermoplastic resin as a main material. A multi-piece solid golf ball having a hardness of 25 or more higher than the Shore D hardness of the mid layer, (2) Go A multi-piece solid golf ball comprising a solid core formed of a composition, at least one intermediate layer covering the core, and at least one cover covering the intermediate layer, wherein the intermediate layer is an olefin-based material. While using one or more thermoplastic elastomers selected from elastomers and modified products thereof, and styrene block copolymers and hydrogenated products thereof,
The Shore D hardness of the intermediate layer is 8 to 24, and the cover is formed to have a Shore D hardness of 57 or more with a thermoplastic resin as a main material. The Shore D hardness of this cover is the Shore D hardness of the intermediate layer.
A multi-piece solid golf ball having a hardness higher than the hardness of 25 or more. (3) The solid core is formed from a rubber base material as a main material and has a specific gravity of 1.1 to 1.5. Has a diameter of 25-40 mm, and the solid core has 1
A multi-piece solid golf ball according to (1) or (2), which has a deformation amount of 2.5 mm or more when a load of 00 kg is applied. (4) The cover is formed of an ionomer resin as a main material. The multi-piece solid golf ball according to any one of (1) to (3), which has a hardness of 57 or more, (5) the intermediate layer has a thickness of 0.2 to 5.0 mm (1)
(6) The multi-piece solid golf ball according to any one of (1) to (4), and (6) the cover has a thickness of 1.0 to 5.0 mm (1).
A multi-piece solid golf ball according to any one of items (5) to (5) is provided.

The present invention will be described in more detail below. The multi-piece solid golf ball G of the present invention comprises:
As shown in FIG. 1, a solid core 1, at least one intermediate layer 2 that covers the core 1, and at least one cover 3 that covers the intermediate layer 2 are provided.

The solid core 1 can be formed from a rubber composition containing a base rubber having polybutadiene rubber, polyisoprene rubber, natural rubber, and silicone rubber as a main component as a main material, and particularly, the resilience is improved. Polybutadiene rubber is preferred for this purpose. The polybutadiene rubber has a cis-structure having a cis-structure of at least 40% or more.
1,4-polybutadiene is preferred. Further, in this base rubber, natural rubber, polyisoprene rubber, styrene-butadiene rubber, etc. can be appropriately blended with the above polybutadiene, if desired, but the resilience of the golf ball is improved by increasing the polybutadiene rubber component. Therefore, the rubber component other than polybutadiene is preferably 10 parts by weight or less with respect to 100 parts by weight of polybutadiene.

In addition to the rubber component, 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 trimethylpropane methacrylate. Particularly, zinc acrylate can be preferably used because of its high resilience. The amount of the cross-linking agent compounded is preferably 15 to 40 parts by weight with respect to 100 parts by weight of the base rubber.

The rubber composition usually contains dicumyl peroxide, a mixture of dicumyl peroxide and 1,1-bis (t-butylperoxy) -3,3,5-trimethylcyclohexane, and the like. Contains a sulfurizing agent,
The compounding amount of this vulcanizing agent was 0.
It can be 1 to 5 parts by weight.

The rubber composition may further contain, if necessary,
Zinc oxide, barium sulfate, or the like can be blended as an antioxidant or a filler for adjusting the specific gravity, and the blending amount of these fillers is 0 to 130 parts by weight with respect to 100 parts by weight of the base rubber.

The above rubber composition for cores is kneaded by using an ordinary kneading machine (for example, Banbury mixer, kneader, roll, etc.), and the obtained compound is injected or compressed by using a core mold. Can be formed by.

The solid core thus obtained is
The diameter is preferably 25 to 40 mm, more preferably 27 to 39 mm, further preferably 30 to 38 mm, the weight is 10 to 40 g, preferably 15 to 35 g, more preferably 20 to 32 g, and the specific gravity is 1. 1-1.
5, preferably 1.12 to 1.45, more preferably 1.15 to 1.40.

The amount of deformation when a load of 100 kg is applied to the solid core is 2.5 mm or more, preferably 2.
8 to 6.0 mm, more preferably 3.0 to 5.5 mm,
More preferably, it is 3.3 to 5.0 mm. If the amount of deformation of the core is less than 2.5 mm, the feeling may become hard, while if it exceeds 6.0 mm, the resilience may decrease.

The core may have a single-layer structure composed of one kind of material or a multi-layer structure composed of two or more layers in which layers composed of different materials are laminated.

In the present invention, at least one layer, preferably one layer or two layers, of the intermediate layer 2 is formed around the core 1 by coating. The mid layer 2 is formed mainly of a very soft thermoplastic resin having a Shore D hardness of 8 to 35.
By forming an extremely soft intermediate layer between the core and the cover as described above, it is possible to realize a very soft and good feeling during approach shots and putting.

As the thermoplastic resin for the intermediate layer,
A heated mixture of (A) a thermoplastic polyester elastomer and (B) an olefin elastomer and a modified product thereof, and one or more thermoplastic elastomers selected from a styrene block copolymer and a hydrogenated product thereof, Alternatively, the component (B) thermoplastic elastomer can be used alone.

Here, as the thermoplastic polyester elastomer as the component (A), terephthalic acid, 1,4-butanediol and polytetramethylene glycol (PT) are used.
Polyester ester multi-block synthesized from MG) or polypropylene glycol (PPG), with polybutylene terephthalate (PBT) part as hard segment and polytetramethylene glycol (PTGM) or polypropylene glycol (PPG) part as soft segment. Copolymers are preferred.
Specifically, Hytrel 3078 and Hytrel 404
7, commercial products such as Hytrel 4767 (manufactured by Toray DuPont) can be used.

The olefin elastomer of the component (B) is a copolymer of ethylene and an alkene having 3 or more carbon atoms, preferably a copolymer of ethylene and an alkene having 3 to 10 carbon atoms, or α- Examples thereof include an olefin, an unsaturated carboxylic acid ester, and a polymerizable monomer containing a carboxyl group or a carboxylic acid anhydride group. Examples of the olefin elastomer include ethylene-propylene copolymer rubber, ethylene-butene copolymer rubber, ethylene-hexene copolymer rubber, ethylene-octene copolymer rubber and the like. Furthermore, ethylene-propylene-non-conjugated diene as a third component, for example, 5-ethylidene norbornene, 5-methyl norbornene, 5-vinyl norbornene, dicyclopentadiene, butene and the like ethylene-propylene-butene copolymer, ethylene -Propylene-butene copolymer rubber, ethylene-ethyl acrylate copolymer resin, etc. may be mentioned.

Specific examples of such olefinic elastomers include "MITUIPT", "Toughmer" (manufactured by Mitsui Petrochemical Industry Co., Ltd.), "ENGAGE" (manufactured by Dow Chemical Japan Co., Ltd.), and "Dynaron" (Japan). Commercially available products such as synthetic rubber) can be used.

Further, modified products of the above-mentioned olefin-based elastomers can also be preferably used. Examples of such modified olefin-based elastomers include ethylene-ethyl acrylate copolymer resin graft-modified with maleic anhydride. Specifically, commercially available products such as “HPR” (manufactured by Mitsui DuPont Polychemical Co., Ltd.) can be used.

Next, as the styrene-based block copolymer, a polymer whose conjugated diene block is composed of butadiene alone, isoprene alone, or a mixture of isoprene and butadiene is preferable. In addition, hydrogenated products of these styrene block copolymers can be preferably used, for example, hydrogenated products of styrene-butadiene-styrene block copolymers, hydrogenated products of styrene-isoprene-styrene block copolymers, and the like. Is mentioned.

Specific examples of hydrogenated products of such styrene-conjugated diene block copolymers include "Dyalon" (manufactured by Japan Synthetic Rubber Co., Ltd.), "Septon", "High Blur" (manufactured by Kuraray Co., Ltd.), A commercially available product such as "Tuftec" (manufactured by Asahi Kasei Corporation) can be used.

The intermediate layer of the present invention is one selected from the above-mentioned (A) thermoplastic polyester-based elastomer, (B) olefin-based elastomer and its modified product, styrene-based block copolymer and its hydrogenated product, or It can be formed by using a heated mixture of two or more kinds as a main material, and in this case, the mixing ratio of the two is 95% by weight or less of the component (A),
The ratio (A) / (B) is preferably 95 to 0/5 to 100% by weight, more preferably 90 to 5/10 to 95% by weight, and further preferably 80 to 10/20 to 90% by weight.

A commercially available product can be used as the mixture of the components (A) and (B), and examples thereof include "Primalloy" (manufactured by Mitsubishi Chemical Corporation).

Further, a thermoplastic elastomer in which one kind or a combination of two or more kinds selected from the component (B), an olefin elastomer and a modified product thereof, and a styrene block copolymer and a hydrogenated product thereof is used. It can be used as a main material of the intermediate layer.

In addition to the above resin components, if necessary, a weight adjusting agent, a colorant, a dispersant, etc. may be added to the intermediate layer composition.

The method for coating the above-mentioned intermediate layer around the core is not particularly limited, and ordinary injection molding or compression molding can be adopted.

The Shore D hardness of the intermediate layer thus formed is required to be 8 to 35, preferably 9 to 30, more preferably 10 to 29, still more preferably 12 to 27. Most preferably, it is 15-24.
If the Shore D hardness is less than 8, the intermediate layer becomes too soft,
The resilience and durability are reduced and it becomes difficult to withstand use. On the other hand, when the Shore D hardness is more than 35, the intermediate layer becomes too hard, and the shot feeling during approach shots and putting becomes hard, and the object of the present invention cannot be achieved.

The thickness of the intermediate layer is preferably 0.2-.
It is 5.0 mm, more preferably 0.5 to 4.0 mm, and further preferably 0.7 to 3.5 mm.

Next, the cover 3 is formed around the intermediate layer 2 so as to cover at least one layer, preferably one layer or two layers. The cover 3 is formed mainly of a thermoplastic resin having a Shore D hardness of 25 or more higher than that of the intermediate layer.

The cover can be formed by using a usual thermoplastic resin as a main material. For example, an ionomer resin,
Examples thereof include polyester-based elastomers, polyamide-based elastomers, styrene-based elastomers, polyurethane-based elastomers, olefin-based elastomers and mixtures thereof, and ionomer resins are particularly preferable.
Specifically, commercially available products such as "Himilan" (manufactured by Mitsui-DuPont Polychemical Co., Ltd.) and "Sarrin" (manufactured by DuPont Co., Ltd.) can be used. In addition, a UV absorber, an antioxidant, a dispersant such as metal soap, and the like can be added to the cover material, if necessary.

There are no particular restrictions on the method of coating the periphery of the intermediate layer with this cover, and ordinary injection molding or compression molding can be employed.

The Shore D hardness of the cover thus formed is 57 or more, preferably 58 to 70, more preferably 59 to 65, and the hardness of the cover is 25 or more Shore D higher than the hardness of the intermediate layer. Is required, preferably 25 to 50, and more preferably 29 to 45. If the hardness difference between the cover and the intermediate layer is less than 25, the cover becomes soft and the resilience decreases. On the other hand, when it exceeds 50, the hardness difference becomes too large, the durability is lowered, and the energy loss is increased, and the flight distance may be shortened.

The thickness of the cover is 1.0 to 5.0 m.
m, preferably 1.2 to 4.0 mm, more preferably 1.3 to 3.0 mm, still more preferably 1.4 to 2.5 m.
m.

The multi-piece solid golf ball of the present invention has the above-mentioned constitution, and has a relatively soft core, a very soft intermediate layer which covers the core, and a relatively hard intermediate layer which covers the intermediate layer. By combining with the cover, these have a good feeling that they are very soft on approach shots and puttings, and also have excellent flight performance on full shots with a driver.

The golf ball of the present invention has a large number of dimples formed on the surface thereof, and the surface can be subjected to finishing treatment such as painting and stamping, if necessary. Further, the hardness of the entire ball is a deformation amount when a load of 100 kg is applied, preferably 2.3 to 5.0 mm, more preferably 2.6 to 4.8 mm, and further preferably 2.
8 to 4.6 mm, the ball diameter and the weight are 42.67 mm or more and the weight is 4 in accordance with the R & A golf rules.
It can be formed to 5.93 g or less.

[0044]

According to the present invention, an approach shot,
It is possible to obtain a multi-piece solid golf ball which has a soft and good feeling at the time of putting and has an excellent flight performance at the time of a full shot with a driver.

[0045]

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. The blending amounts in Tables 1, 2, and 3 are all parts by weight.

[Examples and Comparative Examples] The rubber compositions for cores having the compounding formulations shown in Table 1 were kneaded with a kneader and vulcanized in a core mold at a temperature of 155 ° C. for about 15 minutes. Solid cores of 1 to 7 and Comparative Examples 1 to 6 were prepared.

The intermediate layer material shown in Table 2 and the cover material shown in Table 3 were coated around the obtained core by injection molding to form Examples 1 to 7 and Comparative Examples 1, 2, 4, and 4. 5
A three-piece solid golf ball was created.

Further, the three-piece ball of Comparative Example 3 is
A pair of half shells was previously molded with the intermediate layer material in Table 2, and the cores were encapsulated with these half shells.
A double solid core was prepared by vulcanizing at 5 ° C for 15 minutes, and a cover was formed by injection molding around the double core. Comparative Example 6 is a two-piece golf ball including a core having no intermediate layer and a cover.

Next, regarding the obtained golf ball,
Various properties were evaluated by the methods shown below. The results are also shown in Tables 4 and 5. Deformation amount of solid core The deformation amount (mm) of the core when a load of 100 kg was applied to the core was expressed. Flying performance At a head speed of 45 m / sec (HS45), the club is a driver (# W1) ("PRO230 Titan" loft 10 with a swing robot manufactured by Miyamae Co., Ltd.).
Degree (made by Bridgestone Sports Co., Ltd.), the carry, the total flight distance, and the spin amount when actually hitting were measured. Also, the club is the 9th iron (# I9) ("MOD
EL 55-HM "head speed 33m / s instead of loft 44 degrees (made by Bridgestone Sports Co., Ltd.)
The spin rate at the time of actual hitting with ec (HS33) was similarly measured. Feeling of hitting 5 golf players (# W1), 9 iron (# I9) and putter (#P)
The feel when hitting with T) was evaluated according to the following criteria. ○: Extremely soft △: Normal ×: Hard continuous impact durability The obtained ball was moved by a swing robot manufactured by Miyamae Co., Ltd. to a driver (“PRO230Titan”).
Loft 10 degrees "(manufactured by Bridgestone Sports Co., Ltd.)
After being repeatedly hit with a head speed of 45 m / sec (HS45), the state of the ball surface was relatively evaluated according to the number of hits according to the following criteria. ◯: No problem at all △: Destruction relatively early ×: Destruction early

[0050]

[Table 1] *: BR01 manufactured by Japan Synthetic Rubber Co., Ltd.

[0051]

[Table 2] * 1: "Hytrel" Toray-Dupont polyester elastomer * 2: "Pebax" Atochem polyamide elastomer * 3: "Primalloy" Mitsubishi Chemical Industries Ltd. polyester elastomer * 4: "HPR" Mitsui DuPont ethylene / ethyl acrylate copolymer resin modified with maleic anhydride * 5: "Tuftec" Asahi Kasei styrene elastomer * 6: "Himilan" Mitsui DuPont Polychemical Ionomer resin * 7: "Surlyn" DuPont ionomer resin

[0052]

[Table 3] * 6: “Himilan” Mitsui DuPont Polychemicals ionomer resin * 7: “Surlyn” DuPont ionomer resin

[0053]

[Table 4] * 8: Core + middle layer

[0054]

[Table 5] * 8: Core + middle layer

As is clear from the results of Tables 4 and 5, the balls of Comparative Examples 1 to 5 all had a Shore D hardness of 4 in the intermediate layer.
Since it is 0 or more and the difference in hardness between the cover and the intermediate layer is less than 25, the function and effect of the present invention cannot be obtained.

That is, Comparative Example 1 is a three-piece ball of the same type as in Japanese Patent Laid-Open No. 7-24084, and the flight distance on driver shots is relatively increased, but the feel on impact with the driver and putter is hard and inferior. is there.

Comparative Example 2 is a three-piece ball of the same type as in Japanese Patent Laid-Open No. 4-244174, which has a reduced flight distance at the time of a full shot with a driver and a hard hit feeling.

Comparative Example 3 is a three-piece ball of the same type as in Japanese Patent Laid-Open No. 6-23069, which has a reduced flight distance at the time of a full shot with a driver, and has a feel on impact with any of the driver, 9-iron and putter. It is hard and inferior.

Comparative Example 4 is a three-piece ball of the same type as that disclosed in Japanese Patent Application Laid-Open No. 9-10358, in which the flight distance at the time of a full shot with a driver is shortened and the feel at impact is also inferior.

Comparative Example 5 is a three-piece ball of the same type as that disclosed in Japanese Patent Laid-Open No. 9-313643. Although the flight distance on a full shot with a driver is relatively increased, the feel on impact with the driver is hard and inferior. .

Comparative Example 6 is a soft type two-piece solid golf ball, which has a reduced flight distance at the time of a full shot with a driver, and is extremely inferior in continuous impact durability.

On the other hand, the three-piece balls of Examples 1 to 7 are very soft and good in hitting feeling with any of the driver, the 9-iron and the putter, and
The flight distance at the time of a full shot with a driver is dramatically increased.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a multi-piece solid golf ball according to an embodiment of the present invention.

[Explanation of symbols]

1 solid core 2 Middle class 3 cover G golf ball

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shunichi Kashiwagi 20 Onohara, Chichibu City, Saitama Prefecture, within Bridgestone Sports Co., Ltd. (72) Inventor Akira Kawada 20 Onohara, Chichibu City, Saitama Prefecture, within Bridgestone Sports Co., Ltd. (56) References JP-A-9-10358 (JP, A) JP-A-9-225068 (JP, A) JP-A-7-24084 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) ) A63B 37/00-37/14

Claims (6)

(57) [Claims] 1. A multi-piece solid golf ball comprising: a solid core formed of a rubber composition; at least one intermediate layer covering the core; and at least one cover covering the intermediate layer. For the intermediate layer, a heating mixture of a thermoplastic polyester elastomer, an olefin elastomer and its modified product, and one or more thermoplastic elastomers selected from styrene block copolymers and hydrogenated products thereof is used. The Shore D hardness of the intermediate layer is 8 to 24,
The cover is mainly made of thermoplastic resin and has a Shore D hardness of 5
A multi-piece solid golf ball which is formed to have a hardness of 7 or more and has a Shore D hardness of 25 or more higher than a Shore D hardness of the mid layer. 2. A multi-piece solid golf ball comprising a solid core formed of a rubber composition, at least one intermediate layer covering the core, and at least one cover covering the intermediate layer, wherein For the intermediate layer, one or more thermoplastic elastomers selected from olefin elastomers and modified products thereof, and styrene block copolymers and hydrogenated products thereof are used, and the intermediate layer has a Shore D hardness of 8 or more. ~ 24,
The cover is mainly made of thermoplastic resin and has a Shore D hardness of 5
A multi-piece solid golf ball which is formed to have a hardness of 7 or more and has a Shore D hardness of 25 or more higher than a Shore D hardness of the mid layer. 3. The solid core is formed of a rubber base material as a main material, and has a specific gravity of 1.1 to 1.5, and
The diameter of this solid core is 25 to 40 mm, and the amount of deformation when a load of 100 kg is applied to the solid core is 2.5.
The multi-piece solid golf ball according to claim 1, which has a diameter of at least mm. 4. The multi-piece solid golf ball according to claim 1, wherein the cover is formed of an ionomer resin as a main material and has a Shore D hardness of 57 or more. 5. The multi-piece solid golf ball according to claim 1, wherein the intermediate layer has a thickness of 0.2 to 5.0 mm. 6. The multi-piece solid golf ball according to claim 1, wherein the cover has a thickness of 1.0 to 5.0 mm.