Dunlop Sports Company Limited

Sumitomo Rubber Industries Limited

Kohei Mimura

Takahiro Sajima

Hyoungchol Kim

Masahide Onuki

Kosuke Tachibana

Hironori Takihara

Toshiyuki Tarao

Hidetaka Inoue

Yosuke Yamamoto

Kazuyoshi Shiga

Kazuya Kamino

Hiroaki Tanaka

Mami Tanaka

Kunio Niwa

Yoshiko Matsuyama

Takehiko Hyodo

Masanori Taguchi

Fumiya Suzuki

Yuko Sakurai

An aqueous adhesive for rubber includes rubber latex and an ammonium-salt-based vulcanization acceleration aid. An amount of the ammonium-salt-based vulcanization acceleration aid contained in the aqueous adhesive is preferably not less than 0.01% by weight and not greater than 5.0% by weight in terms of solid content. An aqueous adhesive for a ball includes rubber latex as a main component. A content of an inorganic filler in the aqueous adhesive is not greater than 0.1% by weight in terms of solid content. A ballincludes a hollow coreobtained by crosslinking a rubber composition that contains a vulcanizing agent. The coreis formed of two hemispherical half cores. The two half cores are adhered to each other by using the aqueous adhesive for a ball.

Aqueous adhesive for rubber and aqueous adhesive for ball

Tennis racket frame

A grommet of a racket includes a tubular portion. The tubular portion has a through hole through which a string is passed. The through hole has a base-side opening, a side wall, and a tip-side opening. In the tip-side opening, an inner dimension in a direction parallel to a face is larger than an inner dimension in a direction perpendicular to the face. In the tubular portion, the string is in contact with the side wall from the base-side opening to the tip-side opening.

Racket

A golf ball has a plurality of dimplesand a landon a surface thereof. The golf ball further has a large number of minute projectionsformed on surfaces of the dimplesand the land. An average pitch Pav of these minute projectionsis less than 100 &#x3bc;m. An average height Hav of these minute projectionsis not less than 0.5 &#x3bc;m and not greater than 50 &#x3bc;m. The golf ball satisfies the following mathematical formula.av&#x3c;3*avIn the mathematical formula, Lav represents an average value of distances L between the minute projectionsand other minute projectionsadjacent to the minute projections, and Tav represents an average value of widths T of these minute projections

Golf ball

An object of the present invention is to provide a golf ball traveling a great distance on driver shots. The present invention provides a golf ball comprising a spherical core including an inner layer and an outer layer, an intermediate layer and a cover, wherein a difference (H&#x2212;H) between a hardness (H) at a point outwardly away in a radial direction from a boundary between the inner layer and the outer layer of the spherical core by 1 mm and a hardness (H) at a point inwardly away in the radial direction from the boundary between the inner layer and the outer layer of the spherical core by 1 mm is 0 or more in Shore C hardness, a surface hardness (H) of the spherical core is more than 65 in Shore C hardness, an angle &#x3b1; of a hardness gradient of the inner layer is 0&#xb0; or more, a difference (&#x3b1;&#x2212;&#x3b2;) between the angle &#x3b1; and an angle &#x3b2; of a hardness gradient of the outer layer is 0&#xb0; or more, a total thickness of a thickness (Tm) of the intermediate layer and a thickness (Tc) of the cover is 3 mm or less, and the cover has a highest hardness among the constituent members of the golf ball.

A golf ballincludes a corea coverpositioned outside the coreand a paint filmpositioned outside the coverThe paint filmincludes an inner layerand an outer layerpositioned outside the inner layerA 10% modulus Mo of the outer layeris lower than a 10% modulus Mi of the inner layerA difference (Mi-Mo) between the modulus Mi and the modulus Mo is not less thankgf/cm. The coverhas a Shore D hardness Hc of not less than 50 and not greater than 65. The coverhas a thickness Tc of not less than 0.80 mm and not greater than 1.80 mm.

A golf ball according to the present invention includes a spherical core, a cover member including at least one layer that covers the core, and at least one coating layer that covers the cover member constituting an outermost layer. A plurality of dimples are formed in the cover member constituting the outermost layer. Roughness is formed on the surface of the coating layer. A maximum height Rz and an arithmetic average roughness Ra of the surface of the coating layer satisfy a relationship Rz&#x2265;Ra&#xd7;6.0. The coating layer contains a lustrous material.

A golf ballincludes a core, one or more mid layers, a cover, and dimples. A central hardness Ho and a surface hardness Hs of the core, a hardness Hm(min) of a layer having a lowest hardness among the mid layers, and a hardness Hc of the coversatisfy the following mathematical formulas (1) to (4).&#x3e;15&#x2003;&#x2003;(1)(min)&#x3e;20&#x2003;&#x2003;(2)&#x2212;10&#x3c;(min)&#x2212;&#x3c;15&#x2003;&#x2003;(3)5&#x3c;&#x3c;20&#x2003;&#x2003;(4)An occupation ratio So and a ratio Rs of a number of the dimpleseach having a diameter of from 9.60% to 10.37% of a diameter of the golf ball, relative to a total number of the dimples, satisfy the following mathematical formula (5).&#x2265;&#x2212;2.5*+273&#x2003;&#x2003;(5).

A golf ball has, on a surface thereof, a rugged pattern composed of a land and a large number of dimples. A method for designing the rugged pattern includes the steps of: (1) assuming a large number of circles on a surface of a phantom sphere; (2) assuming a large number of generating pointsbased on positions of the large number of circles; (3) assuming a large number of Voronoi regionson the surface of the phantom sphere by a Voronoi tessellation based on the large number of generating points; and (4) assigning a dimple and a land to the surface of the phantom sphere based on contours of the large number of Voronoi regions

Process for designing rugged pattern on golf ball surface

A golf ballincludes a large number of dimpleson a surface thereof. The surface has a northern hemisphere N and a southern hemisphere S. Each of the hemispheres has a high-latitude region, a mid-latitude regionand a low-latitude region. The high-latitude regionhas a latitude range of 40&#xb0; or greater but 90&#xb0; or less. The mid-latitude regionhas a latitude range of 20&#xb0; or greater but less than 40&#xb0;. The low-latitude regionhas a latitude range of 0&#xb0; or greater but less than 20&#xb0;. The number of planes that can divide a dimple pattern of the hemisphere so that divided dimple patterns are mirror symmetry to each other is one. Neither a dimple pattern of the high-latitude regionnor a dimple pattern of the low-latitude regionis rotationally symmetrical.

A golf ballincludes a main bodyand a paint filmThe paint filmincludes an inner layerand an outer layerA modulus Min of the inner layeris higher than a modulus Mout of the outer layerA difference (Min&#x2212;Mout) is not less than 25 kgf/cm. The golf ballhas a plurality of dimplesA ratio So of a sum of areas of the dimplesrelative to a surface area of a phantom sphere of the golf balland a ratio Rs of a number of the dimpleseach having a diameter of not less than 9.60% and not greater than 10.37% of a diameter of the golf ballrelative to a total number of the dimplessatisfy the following mathematical formula (1).&#x2265;&#x2212;2.5*+273 &#x2003;&#x2003;(1)

A golf ballhas a large number of dimpleson a surface thereof. The contours of the dimplesare non-circular. A standard deviation of areas of the dimplesis equal to or less than 1.7 mm. A ratio of a total area of the dimplesrelative to a surface area of a phantom sphere of the golf ballis equal to or greater than 80%. By comparting lines CS obtained by projecting sides of a regular dodecahedron, which is inscribed in the phantom sphere, onto the phantom sphere, a surface of the phantom sphere can be divided into 12 units Ut each of which meets the following mathematical formula (I):&#x2212;2&#x2266;(/12)&#x2212;&#x2266;2&#x2003;&#x2003;(I),where Nt represents the total number of the dimplesand Nu represents the number of the dimpleson one unit.

An object of the present invention is to provide a golf ball traveling a great distance on driver shots and on iron shots. The present invention provides a golf ball comprising a spherical core including an inner layer and an outer layer, and a cover, wherein a difference (H&#x2212;H) between a hardness (H) at a point outwardly away in a radial direction from a boundary between the inner layer and the outer layer of the spherical core by 1 mm and a hardness (H) at a point inwardly away in the radial direction from the boundary between the inner layer and the outer layer of the spherical core by 1 mm is 0 or more in Shore C hardness, a surface hardness (H) of the spherical core is more than 65 in Shore C hardness, an angle &#x3b1; of a hardness gradient of the inner layer is 0&#xb0; or more, a difference (&#x3b1;&#x2212;&#x3b2;) between the angle &#x3b1; and an angle &#x3b2; of a hardness gradient of the outer layer is 0&#xb0; or more, a thickness of the cover is 3 mm or less, a difference (Hc&#x2212;H) between a hardness (Hc) of the cover and the surface hardness (H) of the spherical core is 2 or more in Shore C hardness, and the cover has a highest hardness among the constituent members of the golf ball.

A golf ball has a large number of dimpleson a surface thereof. The dimplesinclude a plurality of small dimplesS each having an area of less than 8.0 mm, and a plurality of large dimplesL each having an area of equal to or greater than 8.0 mm. A ratio PS of a sum of areas of all the small dimplesS to a surface area of a phantom sphere of the golf ball is less than 2.0%. A ratio PL of a sum of areas of all the large dimplesL to the surface area of the phantom sphere is equal to or greater than 79.0%. A degree G of uniformity of areas of the large dimplesL is equal to or less than 1.15.

Growing community of inventors

Kobe, Japan

Kohei Mimura