Sumitomo Rubber Industries Limited

Sri Sports Limited

Dunlop Sports Company Limited

Sri Soprts Limited

Takahiro Sajima

Keiji Ohama

Kohei Mimura

Seiichiro Endo

Hironori Takihara

Toshiyuki Takubo

Hyoungchol Kim

Yoshiko Matsuyama

Hirotaka Nakamura

Takashi Sasaki

Kosuke Tachibana

Keiji Moriyama

Kazuya Kamino

Toshiyuki Tarao

Masahide Onuki

Kazuhiko Isogawa

Hikaru Nagakura

Kaname Yamada

Kazunari Yoshida

Daijiro Kojima

Kazuyoshi Shiga

Masatoshi Yokota

Hidetaka Inoue

Akira Kato

Satoshi Iwami

Satoko Okabe

Takeshi Asakura

Tetsuo Yamaguchi

Masaki Shiraishi

Hideaki Kawamatsu

Kazuhiro Fujisawa

Akio Miyori

Kaita Fukao

An object of the present disclosure is to provide a golf ball having excellent durability and flight distance and good shot feeling for an average golfer who hits a golf ball at a slow head speed. The present disclosure provides a golf ball comprising a spherical core and at least two cover layers covering the spherical core, wherein a difference between a core surface crosslinking density and a core center crosslinking density is more than 1.0&#xd7;10mol/mand less than 9.0&#xd7;10mol/m, a hardness difference between a core surface hardness Cs (Shore C hardness) and a core center hardness Co (Shore C hardness) is 13.0 or more and 30.0 or less, a compression deformation amount of the core when applying a load from an initial load of 98 N to a final load of 1275 N to the core is less than 3.8 mm, and the at least two cover layers include a first cover layer and a second cover layer positioned closer to the spherical core than the first cover layer, an average hardness Dave=(Ti&#xd7;Hi+To&#xd7;Ho)/(Ti+To) of the first cover layer and the second cover layer is 55 or more, wherein To (mm) is a thickness of the first cover layer, Ho (Shore D) is a slab hardness of the first cover layer, Ti (mm) is a thickness of the second cover layer, and Hi (Shore D) is a slab hardness of the second cover layer.

Golf ball

An object of the present disclosure is to provide a golf ball having excellent durability and flight distance and good shot feeling for an average golfer who hits a golf ball at a slow head speed. The present disclosure provides a golf ball comprising a spherical core and at least two cover layers covering the spherical core, wherein a difference between a core surface crosslinking density and a core center crosslinking density is more than 1.0&#xd7;10mol/mand less than 9.0&#xd7;10mol/m, a hardness difference between a core surface hardness Cs (Shore C hardness) and a core center hardness Co (Shore C hardness) is 13.0 or more and 30.0 or less, a compression deformation amount of the core when applying a load from an initial load of 98 N to a final load of 1275 N to the core is 3.8 mm or more, and the at least two cover layers include a first cover layer and a second cover layer positioned closer to the spherical core than the first cover layer, an average hardness Dave=(Ti&#xd7;Hi+To&#xd7;Ho)/(Ti+To) of the first cover layer and the second cover layer is 55 or more, where To (mm) is a thickness of the first cover layer, Ho (Shore D) is a slab hardness of the first cover layer, Ti (mm) is a thickness of the second cover layer, and Hi (Shore D) is a slab hardness of the second cover layer.

A golf ball includes a core and a cover positioned outside the core. An n-layer (n is a natural number) partial mid layer is provided between the core and the cover. An area of the core in a region where the cover is laminated thereon is not less than 5.0% and not greater than 95.0% of a surface area of a phantom sphere having a radius equal to an average value of a distance from a central point of the core to a surface of the core. In an outer surface of the golf ball, a color difference &#x394;E1 based on a CIELAB color system between a region C where the cover is directly laminated on the core and a region M where the cover is laminated on the partial mid layer is not less than 20.0.

A golf ball includes a core, a mid layer, and a cover. An amount of compressive deformation Cof the golf ball can be not less than 2.80 mm. The golf ball can satisfy the following mathematical formulas (1) and (2):1&#x3e;(124.8&#x2212;)/11.5&#x2003;&#x2003;(1)2&#x2212;1&#x2265;(&#x2212;1/6*1+(68&#x2212;2)/20+(5&#x2212;)/100)*2&#x2003;&#x2003;(2), where Cis an amount of compressive deformation (mm) of the core, Cis an amount of compressive deformation (mm) of a sphere including the core and the mid layer, Hd is Hs&#x2212;Ho, Ho is a hardness (Shore C) of a center the core, Hs is a hardness (Shore C) of a surface of the core, His a hardness (Shore D) of the mid layer, and Tis a thickness (mm) of the mid layer.

A golf ball has a core, an inner cover, an outer cover, and dimples. The golf ball satisfies the following mathematical formulas.=4500+10(&#x2212;0.5&#x2212;2)&#x2265;40000.04+160&#x2212;20&#x2264;&#x2264;0.04+160+20

A golf ball can include a core, a mid layer, and a cover. The golf ball can satisfy the following mathematical formulas (1), (2), and (3):1&#x2264;(124.8&#x2212;)/11.5&#x2003;&#x2003;(1)2&#x2212;1&#x2265;(&#x2212;1/6*1+(68&#x2212;2)/20+(5&#x2212;)/100)*2&#x2003;&#x2003; (2)10&#x2264;2*2&#x2212;3*3&#x2003;&#x2003;(3), where

A golf ball according to an aspect of the present invention is a golf ball having a large number of dimples, a surface of the golf ball is covered with a plurality of virtual flat surfaces each having a triangular shape, one or more dimples are arranged so as to correspond to each of the virtual flat surfaces, and an edge of each dimple is formed in a linear shape. Each dimple may have a triangular pyramid shape or a triangular frustum shape.

A golf ball includes a core and a cover. An n-layer (n is a natural number) partial mid layer is provided between the core and the cover. An area of the core in a region where the cover is laminated thereon is not less than 5.0% and not greater than 95.0% of a surface area of a phantom sphere. A hitting feel index Cx calculated using a thickness T(mm) of the cover laminated on the partial mid layer, a Shore D hardness Cof a kth layer (k is an integer from 1 to n) from the core side, a thickness T(mm) of the kth layer, a Shore D hardness C of the cover, and an average thickness T (mm) of the cover, is less than 66.0. An absolute value |Cx&#x2212;C| is not less than 1.0 and not greater than 5.0.

A golf ballincludes a coreand a coverpositioned outside the core. The coveris formed in a mold having support pins by injection molding. A ratio (V/S) of a volume V (mm) of the coverto an amount of compressive deformation S (mm) of the coreis not less than 1000 and not greater than 1900. The coverhas a shore D hardness of not greater than 62. The golf ballhas a plurality of dimpleson a surface thereof. A total volume W of these dimples is not less than 490 mmand not greater than 620 mm. A ratio (&#x3b1;/P) of a latitude &#x3b1; (degree) of each support pin to a total cross-sectional area P (mm) of the support pins is not less than 0.35 and not greater than 0.60.

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. The surface of the golf ball has an arithmetic average height Sa of not less than 0.5 &#x3bc;m and not greater than 30 &#x3bc;m. An average value Hav of heights H of the minute projectionsis not less than 0.5 &#x3bc;m and not greater than 50 &#x3bc;m. A ratio Pp of a sum of areas of all the minute projectionsto a surface area of a phantom sphere of the golf ball is not less than 7%. An average value Dav of diameters D of the minute projectionsis not less than 5 &#x3bc;m and not greater than 50 &#x3bc;m.

A golf ball has a plurality of minute projectionson a surface thereof. An average value Hav of heights H of these minute projectionsis not less than 0.5 &#x3bc;m and not greater than 50 &#x3bc;m. The surface of the golf ball has one or more first zones and one or more second zones. An average value Hav1 of the heights H of the minute projectionson these first zones is higher than an average value Hav2 of the heights H of the minute projectionson these second zones. Preferably, the average value Hav1 and the average value Hav2 satisfy the following mathematical formula.3&#x2264;(1&#x2212;2)&#x2264;50

A golf ball has a large number of exposed portionson a surface thereof. An average value Hav of heights H of these exposed portionsis not less than 0.5 &#x3bc;m and not greater than 50 &#x3bc;m. The surface of the golf ball has one or more first zones and one or more second zones. An average value Havof the heights H of the exposed portionson these first zones is higher than an average value Havof the heights H of the exposed portionson these second zones. Preferably, the average value Havand the average value Havsatisfy the following mathematical formula.3&#x2264;(Hav&#x2212;Hav)&#x2264;50

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 depth Fav of the dimplesand an average height Hav of the minute projections satisfy the following mathematical formula (1).&#x2265;0.050&#x2003;&#x2003;(1)A ratio M (%) of a sum of areas of all the dimplesrelative to a surface area of a phantom sphere of the golf ball and an average value Pav (&#x3bc;m) of pitches P each between a minute projectionand another minute projectionadjacent to this minute projectionsatisfy the following mathematical formula (2).&#x3e;0.3&#x2003;&#x2003;(2)

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. The minute projectionsare exposed on the surface of the golf ball. The surface of the golf ball has an arithmetic average height Sa of not less than 0.5 &#x3bc;m and not greater than 30 &#x3bc;m. The surface of the golf ball has a maximum height Sz of not less than 5 &#x3bc;m and not greater than 200 &#x3bc;m.

Growing community of inventors

Kobe, Japan

Takahiro Sajima