JP5225310B2 - Multi-piece solid golf ball - Google Patents

Description

  The present invention relates to a multi-piece solid golf ball in which an elastic solid core is covered with a plurality of layers of a resin cover and has a large number of dimples on the surface of the ball. In particular, the golf ball has excellent flying stability and is based on a short iron in a wet state. The present invention relates to a multi-piece solid golf ball having excellent controllability with reduced spin reduction. In the present invention, the wet state refers to a golf course state in rainy weather, and the dry state refers to a golf course state in fine weather.

  Solid golf balls are known that have a structure in which a rubbery elastic core is covered with a relatively hard ionomer resin cover that is excellent in terms of preventing damage such as cut resistance and wear resistance. A large number of dimples are arranged on the outer surface of the cover with a uniform distribution as a target.

  However, the mold used for molding the cover is usually of a two-part type, and its parting surface is located at a position that coincides with the equator of the spherical molding cavity. A die that avoids disposing dimples at the intersecting position (more precisely, avoiding providing a dimple-type protrusion at a position intersecting the parting surface) is generally used. For this reason, even if the dimples are evenly arranged in both hemispheres centering on the equator, the uniformity of the dimples arrangement is lost when viewed as a whole including the vicinity of the equator.

  Due to such uneven distribution or uneven dispersion of dimples, the ball hits the center of the ball and rotates around an axis parallel to the equator plane, and the axis that is orthogonal to the equator plane and passes through both poles of the ball. Since the effect of dimples differs from the case of rotating to the center, there is a problem in that the direction of the hit ball and the flight distance by the club for earning a distance such as a driver vary, and the stability of the flight is lacking.

  On the other hand, golf balls are related to the material surface and physical properties of the cover, and in a dry state (when the weather is fine), the flying distance of the ball with a driver is sufficient, and the spin required for hitting with an iron that requires controllability. Although it is not regarded as a problem, there is a problem that in a wet state in rainy weather, the spin is reduced and the controllability of the hit ball by the iron club is lowered. In particular, the degree of spin of a hit ball by a short iron having a loft of 8 iron or more is deteriorated. As a result, there is a problem that the hit ball is stretched unexpectedly or hardly stops on the green.

  In view of the above, conventional golf balls are not fully satisfactory by advanced technical players such as professional golfers, and their improvement has been strongly demanded.

  As prior art documents related to the present invention, there are the following documents.

Japanese Patent Laid-Open No. 11-137725 JP 2000-325499 A JP 2000-325500 A Japanese Patent Laid-Open No. 11-178949

  The present invention has been made in view of the above circumstances. In a multi-piece solid golf ball in which an elastic solid core is covered with a plurality of resin covers and a ball surface has a large number of dimples, The purpose of the present invention is to provide a high performance multi-piece solid golf ball that increases the spin retention rate of the wet state with respect to the state and at the same time increases the flying stability in the hitting ball by the club for increasing the flight distance of the driver and the like. To do.

  In order to achieve the above object, the present invention provides the following [I] and [II] multi-piece solid golf balls.

[I] In a multi-piece solid golf ball in which a single-layer elastic solid core is covered with a plurality of resin covers and a ball surface has a large number of dimples, the solid core has a diameter of 30 to 40 mm, and has 294N When the load of (30 kgf) is applied, the main material of the inner layer of the cover adjacent to the core is 1.1 mm or more and 4.0 mm or less, the ionomer resin is a fatty acid having a molecular weight of 280 or more The derivative and a basic inorganic metal compound capable of neutralizing each acid group are mixed by heating, and the Shore D hardness of the cover inner layer is in the range of 45 to 70, and the outer cover outer layer The main material is a reaction product of a thermoplastic polyurethane elastomer and an isocyanate compound, and the Shore D hardness of the outer layer of the cover is 35 to 55. Assuming that the Shore D hardness of the cover inner layer is A and the Shore D hardness of the cover outer layer is B, these A and B satisfy the relationship of 3000 ≧ A × B ≧ 2300, and there is no great circle that does not intersect with the dimples. A three-piece solid golf ball comprising a large number of dimples arranged on the ball surface substantially uniformly so as not to exist.

  According to the present invention, by providing the above solution, a seamless golf ball is obtained in which dimples are arranged on the ball surface substantially evenly so that no great circle that does not intersect the dimple exists on the ball surface. The stability of the flight distance with the driver and the iron can be obtained, and the spin of the ball by the short iron having a loft of 8 iron or more can be obtained not only in the dry state (at the time of fine weather) but also in the wet state at the time of rain. Without hitting down, hitting the ball as expected, easy to stop on the green, excellent controllability, stable hitting conditions, flying performance, and spin performance in all conditions from the driver to the green High performance multi-piece solid golf suitable for professional golfers and amateurs Fuboru are those that can be obtained.

  According to the present invention, in a club that earns a flight distance, such as a driver, it has excellent flight stability, suppresses a decrease in spin due to a short iron in a wet state, and has excellent controllability from the driver to all around the green. Under the conditions, a high-quality multi-piece solid golf ball having stable hitting conditions, flying performance, and spin performance can be obtained.

1 is a schematic cross-sectional view of a multi-piece solid golf ball according to an embodiment of the present invention. It is a side view showing a dimple arrangement pattern of golf balls of Examples 1 and 3. 6 is a side view showing a dimple arrangement pattern of a golf ball of Example 2. FIG. 6 is a side view showing a dimple arrangement pattern of a golf ball of Example 4. FIG. It is a side view which shows the dimple arrangement pattern of the golf ball of Comparative Examples 1-3. 10 is a side view showing a dimple arrangement pattern of a golf ball of Comparative Example 4. FIG. 10 is a side view showing a dimple arrangement pattern of a golf ball of Comparative Example 5. FIG.

Hereinafter, the present invention will be described in more detail.
The multi-piece solid golf ball G of the present invention includes, for example, as shown in FIG. 1, a solid core 1, a cover inner layer 2 that covers the core 1, and a cover outer layer 3 that covers the cover inner layer 2. The cover inner layer 2 may be a plurality of layers other than the illustrated example. In FIG. 1, D indicates dimples.

  Here, the solid core 1 is preferably formed of a rubber composition. As the rubber composition, those using polybutadiene as the base material are preferable. As this polybutadiene, 1,4-cis polybutadiene having a cis structure of at least 40% or more is preferably exemplified. In the base rubber, natural rubber, polyisoprene rubber, styrene butadiene rubber, or the like can be appropriately blended with the polybutadiene as desired. By increasing the rubber component, the resilience of the golf ball can be improved.

  The rubber composition may contain a zinc salt of unsaturated fatty acid such as zinc methacrylate or zinc acrylate as a crosslinking agent, or an ester compound such as magnesium salt or trimethylpropane methacrylate, but zinc acrylate is particularly preferred. Can be used for The blending amount of these crosslinking agents is preferably 10 parts by mass or more and 50 parts by mass or less, particularly 20 parts by mass or more and 45 parts by mass or less with respect to 100 parts by mass of the base rubber.

  The rubber composition usually contains a vulcanizing agent, and the vulcanizing agent contains a peroxide that reaches a half-life of 155 ° C. or less in 1 minute. The content thereof is 30% by mass or more, particularly 40% by mass or more of the entire vulcanizing agent, and the upper limit thereof is not particularly limited, but is preferably 70% by mass or less. A commercial item can be used as such a peroxide, for example, perhexa 3M (made by NOF Corporation) etc. are mentioned. The compounding quantity of a vulcanizing agent can be 0.6 to 2 mass parts with respect to 100 mass parts of base rubber.

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

  The solid core composition obtained by blending the above components is kneaded using an ordinary kneader, such as a Banbury mixer or roll, and compressed or injection molded into a core mold, and the molded product is cross-linked with a cross-linking agent and a co-crosslinking When a temperature sufficient for the agent to act, for example, when dicumyl peroxide is used as the vulcanizing agent and zinc acrylate is used as the crosslinking agent, the temperature is about 130 to 170 ° C., particularly 10 to 40 at 150 to 160 ° C. The solid core is prepared by heat curing for 12 minutes, especially 12-20 minutes.

  The rubber composition can be vulcanized and cured by a known method to produce a solid core, but its diameter is 30 mm or more, more preferably 33 mm or more, still more preferably 35 mm or more, and 40 mm or less. More preferably, it is 39 mm or less, and more preferably 38 mm or less.

  In addition, the solid core needs to have a deformation amount of 1.1 mm or more when a load of 294N (30 kgf) is applied, preferably 1.2 mm or more, more preferably 1.4 mm or more, and still more preferably. Is 1.5 mm or more, 4.0 mm or less, preferably 3.5 mm or less, more preferably 3.0 mm or less, still more preferably 2.5 mm or less, and most preferably 2.3 mm or less. When the deformation amount at the time of loading of 294N (30 kgf) is smaller than the above value, the feeling becomes hard, which is not preferable. On the other hand, if the amount of deformation is too large, the resilience and durability may be reduced. The hardness distribution (JIS-C hardness) of the core cross section may be flat between the center and the surface, may be inclined between the center and the surface, or may have a partial hardness difference.

  The specific gravity of the solid core is 1.0 or more, more preferably 1.05 or more, still more preferably 1.1 or more, and the upper limit is 1.3 or less, more preferably 1.25 or less, still more preferably 1. 2 or less.

The core is formed by a single layer structure made of one kind of material .

  Next, in the present invention, a plurality of resin covers, particularly the cover inner layer 2 and the cover outer layer 3 as shown in FIG. 1 are formed around the solid core 1 so that the Shore D hardness of the cover inner layer is 45 to 45. 70, Shore D hardness of the outer cover outer layer is 35 to 55, and it is preferable to form the cover outer layer softer than the cover inner layer.

As the material of the cover inner layer 2, a material obtained by heating and mixing an ionomer resin with a fatty acid having a molecular weight of 280 or more or a derivative thereof and a basic inorganic metal compound capable of neutralizing each acid group is used. it can.

  By further mixing an olefin-based elastomer with the ionomer resin, it is possible to obtain characteristics (for example, hit feeling and resilience) that cannot be achieved when each is used alone. Examples of olefin-based elastomers include linear low-density polyethylene, low-density polyethylene, high-density polyethylene, polypropylene, rubber-reinforced olefin polymers, flexomers, plastomers, and thermoplastic elastomers containing acid-modified products (styrene-based block copolymers, hydrogenated polybutadiene ethylenes). Propylene rubber), dynamically vulcanized elastomers, ethylene acrylate, ethylene vinyl acetate and the like. Specifically, commercially available products such as “HPR” manufactured by Mitsui DuPont Polychemical Co., Ltd. and “Dynalon” manufactured by Nippon Synthetic Rubber Co., Ltd. are used.

  The mixing ratio of the ionomer resin and the olefin elastomer is 40:60 to 95 to 5, preferably 45:55 to 90:10, more preferably 48:52 to 88:12, and particularly 55:45 to 85 in terms of mass ratio. : 15 is desirable. If the amount of the olefin-based elastomer is too small, the feeling of hitting may become hard. On the other hand, if the amount is too large, the resilience may be lowered.

  In addition, ion neutralization types, such as Zn, Mg, Na, Li, can be used for the said ionomer resin. In this case, it is preferable to contain 5 to 100% by mass, more preferably 10 to 80% by mass, and still more preferably 15 to 70% by mass of Zn or Mg ion neutralized ionomer resin which is relatively soft and has high resilience. This ionomer resin may be blended with another polymer as long as the effects of the present invention are not impaired.

  The inner layer of the cover can also be blended with an ionomer resin and a polyester elastomer, and the mixing ratio is 40:60 to 95: 5, preferably 45:55 to 90:10, and more preferably 48:48 by mass ratio. It is preferable that it is 52-88: 12, More preferably, it is 55: 45-85: 15. If the amount of the polyester-based elastomer is too small, the feeling of hitting may become hard. On the other hand, if the amount is too large, the resilience may decrease.

  In addition, the cover inner layer is formed by heating and mixing a fatty acid having a molecular weight of 280 or more and a derivative thereof and a basic inorganic metal compound capable of neutralizing each acid group into the ionomer resin to neutralize the acid groups of the ionomer resin. The material which improved can be used. Furthermore, as the inner layer of the cover, an ionomer resin (for example, Himilan AM7317, AM7318 (manufactured by Mitsui DuPont Polychemical Co., Ltd.), etc.) in which the acid content of the ionomer resin is improved can be used.

  The cover inner layer preferably contains about 30% by mass, particularly 1 to 20% by mass of an inorganic filler such as zinc oxide, barium sulfate, or titanium dioxide.

The Shore D hardness of the cover inner layer is 45 or more, preferably 50 or more, more preferably 53 or more, still more preferably 55 or more, and 70 or less, preferably 68 or less, more preferably 66 or less, still more preferably 64 or less. More preferably, it is 62 or less . If the Shore D hardness of the cover inner layer is too low, the resilience of the ball will be reduced, while if it is too high, the hit feeling will be hard.

  Further, the specific gravity of the cover inner layer is 0.8 or more, more preferably 0.9 or more, further preferably 0.92 or more, most preferably 0.93 or more, and 1.4 or less, more preferably 1.16. Hereinafter, it is more preferably 1.1 or less, and most preferably 1.05 or less.

  The cover inner layer has a thickness of 0.5 mm or more, preferably 0.7 mm or more, more preferably 0.9 mm or more, still more preferably 1.1 mm or more, and 3.0 mm or less, more preferably 2. It is 5 mm or less, More preferably, it is 2.0 mm or less.

As the material of the cover outer layer 3, a material mainly composed of a reaction product of a thermoplastic polyurethane elastomer and an isocyanate compound can be used.

  Here, as a thermoplastic polyurethane-type elastomer, the molecular structure contains the high molecular polyol compound which comprises a soft segment, the monomolecular chain extender which comprises a hard segment, and diisocyanate.

  Although it does not restrict | limit especially as a high molecular polyol compound, For example, a polyester-type polyol, a polyether-type polyol, a copolyester-type polyol, or a polycarbonate-type polyol etc. are mentioned. Examples of the polyester-based polyol include polycaprolactone glycol, poly (ethylene-1,4-adipate) glycol, and poly (butylene-1,4-adipate) glycol. Examples of the copolyester polyol include poly (diethylene glycol adipate). ) Glycol and the like, examples of the polycarbonate-based polyol include (hexanediol-1,6-carbonate) glycol, and examples of the polyether-based polyol include polyoxytetramethylene glycol. The number average molecular weight of these polyol compounds is about 600 to 5000, preferably 1000 to 3000.

  As the monomolecular chain extender, usual polyhydric alcohols and amines can be used, for example, 1,4-butylene glycol, 1,2-ethylene glycol, 1,3-propylene glycol, 1,6-hexylene. Examples include glycol, 1,3-butylene glycol, dicyclohexylmethylmethanediamine (hydrogenated MDA), and isophoronediamine (IPDA).

As the diisocyanate, aliphatic diisocyanate or aromatic diisocyanate can be suitably used. Specific examples of the aliphatic diisocyanate include hexamethylene diisocyanate (HDI), 2,2,4 (2,4,4) -trimethylhexamethylene diisocyanate (TMDI), and lysine diisocyanate (LDI). Examples of the aromatic diisocyanate include 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, and 4,4-diphenylmethane diisocyanate.
Among these, aliphatic diisocyanates are particularly preferable from the viewpoint of yellowing resistance of the cover, and HDI is particularly preferable from the viewpoint of compatibility when blended with other resins.

  The thermoplastic polyurethane-based elastomer preferably has a tan δ peak temperature of −15 ° C. or less, particularly −16 ° C. or less, and a lower limit of −50 ° C. or more as measured by viscoelasticity, from the viewpoint of softness and resilience.

  As such a thermoplastic polyurethane-based elastomer, commercially available products can be used, for example, Pandex T7298 (−20 ° C.), T7295 (−26 ° C.), T7890 (−30 ° C.) (DIC Bayer Polymer Ltd.) And the like, in which the diisocyanate is aliphatic. The numbers in parentheses indicate tan δ peak temperatures.

As the cover outer layer material of the present invention, the surface durability at the time of hitting an iron can be further improved by using the reaction product of the above-mentioned thermoplastic polyurethane elastomer and an isocyanate compound.

  The isocyanate compound can be used without particular limitation as long as it is an isocyanate compound used in ordinary polyurethanes. For example, as an aromatic isocyanate compound, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, or both of them can be used. , 4,4-diphenylmethane diisocyanate, m-phenylene diisocyanate, 4,4′-biphenyl diisocyanate and the like, and hydrogenated products of these aromatic isocyanate compounds such as dicyclohexylmethane diisocyanate can also be used. Moreover, alicyclic diisocyanates, such as aliphatic diisocyanates, such as tetramethylene diisocyanate, hexamethylene diisocyanate (HDI), and octamethylene diisocyanate, and xylene diisocyanate are mentioned. Furthermore, a blocked isocyanate compound obtained by reacting an isocyanate group of a compound having two or more isocyanate groups at a terminal with a compound having active hydrogen, a uretdione compound obtained by dimerization of isocyanate, and the like can be given.

  The compounding amount of the isocyanate compound is usually 0.1 parts by mass or more, preferably 0.2 parts by mass or more, more preferably 0.3 parts by mass or more, and 10 parts by mass with respect to 100 parts by mass of the thermoplastic polyurethane elastomer. Part or less, preferably 5 parts by weight or less, more preferably 3 parts by weight or less. If the amount is too small, a sufficient crosslinking reaction cannot be obtained and physical properties may not be improved. On the other hand, if the amount is too large, discoloration due to aging, heat and ultraviolet rays may increase, thermoplasticity may be lost, and problems such as reduced rebound may occur.

  These cover materials can be used alone or in combination, and each resin and ionomer resin can be mixed. In addition, it is also possible to mix | blend well-known additives, such as a pigment, a dispersing agent, antioxidant, a ultraviolet absorber, a plasticizer, with a cover material as needed.

  The Shore D hardness of the cover outer layer is 35 or more, preferably 38 or more, more preferably 41 or more, still more preferably 44 or more, most preferably 47 or more, and 55 or less, preferably 53 or less, more preferably 51 or less, More preferably, it is 50 or less, most preferably 49 or less, and is preferably lower than the Shore D hardness of the inner layer of the cover. If the Shore D hardness of the cover outer layer is too low, too much spin tends to be applied, and the flight distance decreases. On the other hand, if it is too high, the amount of spin is reduced too much, the controllability is lowered, and the spin stability at the time of hitting in the dry state and wet state is lowered.

  The specific gravity of the cover outer layer is 0.9 or more, preferably 0.95 or more, more preferably 1.0 or more, still more preferably 1.05 or more, and the upper limit is 1.3 or less, preferably 1.25 or less, More preferably, it is 1.22 or less, More preferably, it is 1.19 or less. The thickness of the cover outer layer is 0.5 mm or more, preferably 0.7 mm or more, more preferably 0.9 mm or more, further preferably 1.1 mm or more, and the upper limit is 2.5 mm or less, preferably 2.3 mm or less. Preferably it is 2.0 mm or less.

  In the present invention, if the Shore D hardness of the cover inner layer is A and the Shore D hardness of the cover outer layer is B, these A and B satisfy the relationship of A × B ≧ 2300, preferably A × B It is preferable that ≧ 2500, more preferably A × B ≧ 2800. If the relationship of A × B ≧ 2300 is deviated, too much spin is applied and the flight distance may decrease.

  In addition, there is no restriction | limiting in particular as a method of forming a cover inner / outer layer, Normal injection molding or compression molding is employable.

  In the present invention, an adhesive layer is preferably provided between the cover inner layer and the cover outer layer for the purpose of improving durability at the time of impact. As the adhesive, an epoxy resin adhesive, a vinyl resin adhesive, a rubber adhesive, or the like can be used, but it is particularly preferable to use a urethane resin adhesive or a chlorinated polyolefin adhesive.

  In this case, the adhesive layer can be formed by dispersion coating, but the type of emulsion used for the dispersion coating is not limited. The resin powder for preparing the emulsion can be either a thermoplastic resin powder or a thermosetting resin powder. For example, vinyl acetate resin, vinyl acetate copolymer resin, EVA (ethylene-vinyl acetate copolymer resin), acrylate ester (Co) polymer resin, epoxy resin, thermosetting urethane resin, thermoplastic urethane resin, and the like can be used. Among these, an epoxy resin, a thermosetting urethane resin, a thermoplastic urethane resin, and an acrylate (co) polymer resin are particularly preferable, and a thermoplastic urethane resin is particularly preferable.

  The thickness of the adhesive layer is preferably 0.1 to 30 μm, more preferably 0.2 to 25 μm, and still more preferably 0.3 to 20 μm.

  The solid golf ball of the present invention thus obtained has a wet state with respect to the spin S1 (rpm) generated when the ball is hit in a dry state using a short iron having a loft of 8 iron or more. The ratio [(S2 / S1) × 100] of the spin S2 (rpm) generated when hit is 47% or more, preferably 48% or more, more preferably 49% or more, still more preferably 50% or more, most preferably 51 % Or more. If the ratio [(S2 / S1) × 100] is less than 47%, the spin controllability difference between the dry state and the wet state is too large to show an improvement effect, and the variation in flight distance becomes large. And the effect cannot be achieved.

  Here, the dry state refers to a normal or fine weather state. The wet state means a golf course state in the rain or a golf course state where the lawn is wet with dew, specifically, a state where the golf ball surface is wet with water.

  As shown in FIGS. 2 to 4, the multi-piece solid golf ball of the present invention is seamlessly formed by arranging a large number of dimples on the ball surface substantially evenly so that there is no great circle that does not intersect with the dimples. Golf ball. By making such a seamless golf ball, there is no variation in the direction and flight distance of the hit ball by the club for earning a distance like a driver, and stability can be obtained.

  In this case, a known method can be adopted as the dimple arrangement method, and the dimple arrangement method is not particularly limited as long as the dimples are uniformly arranged. However, the octahedral arrangement, the icosahedron arrangement, the hemisphere is equally divided into 2 to 6 and the like. The spherical division method can be adopted, and the dimples can be arranged in the divided area. Note that a method of performing fine correction on these methods can be used.

  The total number of dimples is 360 or more and 540 or less, more preferably 380 or more, further preferably 390 or more, more preferably 450 or less, and still more preferably 400 or less.

  In the present invention, the dimple shape is usually a planar circle, and its diameter is 1.8 mm or more, more preferably 2.4 mm or more, still more preferably 3.0 mm or more, and 4.6 mm or less, more preferably 4 mm. 0.4 mm or less, more preferably 4.2 mm or less. The depth is 0.08 mm or more, more preferably 0.1 mm or more, still more preferably 0.12 mm or more, and 0.22 mm or less, more preferably 0.2 mm or less, still more preferably 0.19 mm or less. Is preferred. In this case, there are two or more kinds of dimples whose diameters are different from each other, more preferably three or more kinds, more preferably four or more kinds, and various kinds of dimples having a combination of six kinds or less, particularly five kinds or less, having different diameters. It is preferable that The depths may be different from each other.

Specifically, as shown in FIG. 2, the dimple arrangement of the golf ball of the present invention is a regular icosahedron arrangement and has a total of 420 four types of dimples D1 to D4 having different diameters, and these dimples intersect. There are no great circles evenly arranged (the dimples intersecting the equator E, which is one of the great circles, are indicated by diagonal lines).
As shown in FIG. 3, a regular octahedron arrangement having a total of 392 three types of dimples D1 to D3 having different diameters, and no great circles that do not intersect these dimples are evenly arranged. (Dimples crossing the equator E, one of the great circles, are shown with diagonal lines).
As shown in FIG. 4, it is a regular icosahedron arrangement with a total of 432 four types of dimples D1 to D4 having different diameters, and there is no single great circle that does not intersect these dimples. (Dimples crossing the equator E, one of the great circles, are shown with diagonal lines).

On the other hand, as shown in FIG. 5, a total of 420 three types of dimples D1 to D3 having different diameters are arranged in a pseudo icosahedron arrangement, and dimples intersect the equator E, which is one of the great circles. The land is continuous.
As shown in FIG. 6, a total of 432 dimples D1 to D3 having three different diameters are arranged in a pseudo icosahedron arrangement, and the dimple does not intersect the equator E, which is one of the great circles. The land is continuous.
The golf ball shown in FIG. 7 has a dimple arrangement that has been applied to a commercially available thread wound golf ball. This dimple does not intersect the equator, and the land portion is continuous.
These golf balls having the dimple arrangement shown in FIGS. 5 to 7 have great circles in which the dimples do not intersect, the dimples are not evenly arranged, and the hitting direction and the flying distance by the club for earning a distance like a driver Variations occur and lack flight stability.

  The diameter and weight of the golf ball of the present invention conforms to the golf rules, but the diameter is 42.67 mm or more, 44 mm or less, more preferably 43.5 mm or less, and still more preferably 43 mm or less. preferable. Further, the weight is 45.92 g or less, preferably 44.5 g or more, more preferably 44.8 g or more, still more preferably 45 g or more, and most preferably 45.1 g or more.

  EXAMPLES Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated concretely, this invention is not restrict | limited to the following Example.

[Examples and comparative examples]
According to a conventional method, on the solid core shown in Table 1, the cover inner layer and the cover outer layer shown in Tables 2 and 3 are sequentially formed, and the dimples are uniformly formed, and the two-piece solid golf ball or the three-piece solid shown in Tables 4 and 5 A golf ball was manufactured.

＊ポリブタジエン：ＪＳＲ ＢＲ１１（日本合成ゴム社製）
＊ジクミルパーオキサイド：パークミルＤ（日本油脂社製）
＊老化防止剤：ノクラックＮＳ６（大内新興化学社製）

* Polybutadiene: JSR BR11 (manufactured by Nippon Synthetic Rubber)
* Dicumyl peroxide: Park mill D (manufactured by NOF Corporation)
* Anti-aging agent: NOCRACK NS6 (Ouchi Shinsei Chemical Co., Ltd.)

＊表中、添加剤の数値は樹脂成分の合計（１００）に対する値を示す。

* In the table, the numerical value of the additive indicates a value relative to the total (100) of the resin components.

＊表中、添加剤の数値は樹脂成分の合計（１００）に対する値を示す。
＊パンデックス：ＤＩＣ・バイエルポリマー社製、熱可塑性ポリウレタン系エラストマー
＊ニュクレル：三井・デュポンポリケミカル社製、エチレン・メタクリル酸・アクリル酸エステル共重合体及びエチレン−メタクリル酸共重合体
＊ハイミラン：三井・デュポンポリケミカル社製、アイオノマー樹脂
＊ダイナロン：ＪＳＲ社製、ポリブタジエン水素添加物
＊サーリン：米国デュポン社製、アイオノマー樹脂
＊ジシクロヘキシルメタンジイソシアネート：住友バイエルウレタン工業社製
＊ハイトレル：東レ・デュポン社製、熱可塑性ポリエステルエラストマー

* In the table, the numerical value of the additive indicates a value relative to the total (100) of the resin components.
* Pandex: DIC / Bayer Polymer, thermoplastic polyurethane elastomer * Nucleel: Mitsui / DuPont Polychemical, ethylene / methacrylic acid / acrylic acid ester copolymer and ethylene-methacrylic acid copolymer * High Milan: Mitsui -DuPont Polychemical Co., Ltd., ionomer resin * Dynalon: JSR Co., polybutadiene hydrogenated * Surlyn: US DuPont, ionomer resin * dicyclohexylmethane diisocyanate: Sumitomo Bayer Urethane Kogyo Co., Ltd. * Hytrel: Toray DuPont, Thermoplastic polyester elastomer

  Each of the obtained golf balls was subjected to a flight test by the following method, and the spin and flight distance was measured with a No. 9 iron (# I9) under dry and wet conditions, and the spin retention rate (%) and flight distance were measured. The difference (m) was calculated. Furthermore, using a sand wedge (#SW), the spin performance at the approach shot and the stop on the green were evaluated. The results are shown in Tables 4 and 5.

Fly Test Using a swing robot manufactured by Miyamae, each ball was hit 20 times with a driver (# W1) at a head speed (HS) of 50 m / s, and the carry and total flight distance were measured.
<Use club>
Head: Bridgestone Sports, J's-METAL,
Loft angle 7.5 °, lie angle 57 °, SUS630 stainless steel,
Lost wax manufacturing method Shaft: Harmotech Pro, HM-70, LK (advanced tone), hardness X
Using a spin No. 9 iron (# I9) with a head speed (HS) of 34 m / s, the dry state (humidity 40%) and the wet state (the club face and ball wetted with water), respectively, immediately after impact The behavior of the ball was photographed and calculated by photographic resolution.
Approach test Using the swing robot, hit each ball 10 times at a head speed (HS) of 20 m / s with a sand wedge (#SW) [Classical Edition; manufactured by Bridgestone Sports Co., Ltd.] Images were taken and spin was calculated by photographic resolution. Moreover, the distance until the ball dropped on the green and stopped was measured.

1 Solid core 2 Cover inner layer 3 Cover outer layer G Golf ball D Dimple E Equator

Claims (5)

In a multi-piece solid golf ball in which a single-layer elastic solid core is covered with a plurality of resin covers and a ball surface has a large number of dimples, the solid core has a diameter of 30 to 40 mm, and has 294 N (30 kgf). The main material of the inner layer of the cover adjacent to the core has a hardness that is deformed to 1.1 mm or more and 4.0 mm or less when a load of A basic inorganic metal compound capable of neutralizing each acid group is heated and mixed, the Shore D hardness of the inner layer of the cover is in the range of 45 to 70, and the main material of the outer layer of the outer cover is , A reaction product of a thermoplastic polyurethane elastomer and an isocyanate compound, and the Shore D hardness of the outer layer of the cover is 35 to 55; -When the Shore D hardness of the inner layer is A and the Shore D hardness of the outer layer of the cover is B, these A and B satisfy the relationship of 3000 ≧ A × B ≧ 2300 and there is no great circle that does not intersect with the dimples. A three-piece solid golf ball characterized in that a large number of dimples are arranged on the ball surface substantially evenly. The three-piece solid golf ball according to claim 1, wherein the cover outer layer is formed to be softer than the cover inner layer. The three-piece solid golf ball according to claim 1 or 2, wherein the thermoplastic polyurethane elastomer of the cover outer layer is obtained using an aromatic or aliphatic diisocyanate. The three-piece solid golf ball according to claim 1, wherein an adhesive layer is interposed between the cover inner layer and the cover outer layer. The specific gravity of the core is 1.0 to 1.3, the specific gravity of the cover inner layer is 0.8 to 1.4, and the specific gravity of the cover outer layer is 0.9 to 1.3. The three-piece solid golf ball according to claim 1.

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