Abstract: A solid golf ball of four layers or multilayer structure having a core, an enclosing layer, an intermediate layer, and a cover. The core is composed of a thermoplastic resin or elastomer and has a diameter of 3-18 mm and a Shore D hardness of 50-95. The enclosing layer is composed of a thermoplastic resin or elastomer. The golf ball offers pleasant feel and click when hit, improved durability, and increased distance.

Abstract: A solid golf ball comprises a solid core (1) and a cover (2). The solid core (1) has a multilayer construction with a core inner layer (3) and a core outer layer (4). The core inner layer has a diameter of 15-22 mm and a Shore D hardness of 40-70. It has a specific gravity from 1.10 to 1.65. The core outer layer has a JIS-C hardness of 40-75. It has a specific gravity of 1.05 to 1.25. The core inner and outer layers are formed of polybutadiene base rubber compositions. The specific gravity of the core inner layer is greater than the specific gravity of the core outer layer. The cover has a gage of 0.5-3 mm. The ball provides an increased carry when hit by a low head speed player, as well as better feel.

Abstract: A golf ball includes a core, two or more intermediate layers, and a cover. In the golf ball, convex ribs are formed on the outer surface of the innermost intermediate layer (surrounding layer) covering the core such that the ribs intrude into an intermediate layer adjacent to the surrounding layer. Further, the hardness of the surrounding layer is made greater than those of the core and the intermediate layer adjacent to the surrounding layer.

Abstract: In a golf ball whose outer layer cover is harder than the inner layer cover, convex ribs are formed on the inner surface of the outer layer cover such that the convex ribs intrude into the inner layer cover. When the apexes of each spherical triangle of a hypothetical octahedron or icosahedron assumed on the inner surface of the outer layer cover are each represented by A, the center of the triangle is represented by B, the midpoint of each side of the triangle is represented by C, and a point on a line connecting the center B and each apex A is represented by D, a convex rib is arranged along each of a line between point A and point D, a line between point B and point D, and a line between point C and point D.

Abstract: A golf ball includes a core, an intermediate layer, and a cover. At a boundary between the core and the intermediate layer or at a boundary between the intermediate layer and the cover, convex ribs are arranged in a network pattern on a first layer such that the convex ribs intrude into a second layer adjacent to the first layer. The first layer having the convex ribs is made harder than the second layer which receives the convex ribs, and cutaway portions are formed between the convex ribs.

Abstract: A golf ball includes a liquid core, an outer-layer core formed to enclose the liquid core, and a cover formed to cover the outer-layer core. The liquid core is formed of a hollow sphere which contains a liquid therein. The hollow sphere is formed of a resin having an Izod impact resistance of 50 J/m or more and a wall thickness of 0.5-2.5 mm. The outer-layer core is formed of a vulcanized rubber and has a wall thickness of 7-11 mm. The golf ball provides soft hit feel and has excellent travel performance such as flat trajectory and extended run. Also, the golf ball of the present invention has excellent resilience and improved durability.

Abstract: In a golf ball comprising a core, an intermediate layer, and a cover, the core is formed primarily of polybutadiene rubber, the intermediate layer is formed primarily of a resin having an Izod impact strength of at least 50 J/m and provided on its outer surface with a plurality of recesses, and the cover is provided on its inner surface with a plurality of protrusions. The resin of which the cover is made has a higher Shore D hardness and a lower melting point than the intermediate layer-forming resin. Due to the embedment of the protrusions in the recesses, the golf ball has improved performance.

Abstract: In a thread-wound golf ball comprising a two-layer structure center ball consisting of an inner layer and an outer layer, a rubber thread layer, and a cover, the center ball has a diameter of 30-36 mm and a weight of 19.5-31.5 g. The center ball outer layer has a specific gravity of 1.0-1.2, a Shore D hardness at least 5 units lower than the inner layer, and a thickness of 1-6 mm. The cover has a thickness of 1-3 mm. This construction and combination of characteristics gives the golf ball excellent spin, control, flight performance, and distance at all club head speeds, and especially increased distance when hit by a low head-speed golfer.

Abstract: A solid golf ball comprises a solid core and a cover. The solid core has a multilayer construction with an inner core layer and an outer core layer. The inner core layer is composed primarily of a resin, and has a diameter of 15-25 mm and a Shore D hardness of 55-90. The outer core layer is formed of a polybutadiene base rubber composition and has a JIS-C hardness of 35-75. The cover has a thickness of 0.5-3 mm. The ball provides an increased carry when hit by a low head speed player, as well as better durability and feel.

Abstract: A golf ball includes a hollow core formed of a material having a specific gravity of 1.05-1.25 and having a concentric spherical inner cavity, a cover formed on the outer surface of the hollow core, and a resin layer applied onto the inner surface of the hollow core and having a thickness of 1-3 mm. The resin layer is preferably formed of a material having an Izod impact resistance of 50 J/m or greater. The hollow core preferably has a wall thickness of 7-11 mm. The Shore D hardness of the resin layer is preferably greater than that of the hollow core by at least 10. The golf ball does not suffer breakage of the hollow core due to an impact acting on the golf ball upon being hit, and has proper degrees of hardness and resilience in order to increase travel distance.

Abstract: A golf ball includes a spherical outer-layer core having a concentric spherical inner cavity and having a wall thickness of 5-10 mm. A spherical inner-layer core having a diameter smaller than that of the spherical cavity is disposed within the spherical cavity of the outer-layer core. A cover is formed on the outer surface of the outer-layer core. A liquid is charged into the space between the outer-layer core and the inner-layer core to thereby form a liquid layer having a thickness of 1-3 mm. The liquid has a specific gravity substantially equal to that of the material of the inner-layer core. In the golf ball, the inner-layer core and outer-layer core can rotate independently while the golf ball is traveling. Also, the golf ball has sufficient resilience and strength.

Abstract: A wound golf ball comprising a center, a thread rubber layer and a cover has a weight of 40-45 grams and a distortion of 2.6-3.6 mm under a load of 100 kg. The center has an outer diameter of 30-35 mm and a distortion of 1.6-4 mm under a load of 30 kg. The cover has a Shore D hardness Hd of 50-68 and a gage of 1.2-2.2 mm. A percent overall dimple volume Vr which is defined as the sum of the volumes of dimple spaces each below a circular plane circumscribed by the dimple edge divided by the volume of the ball satisfies: (0.985-0.002 Hd).ltoreq.Vr.ltoreq.(1.085-0.002 Hd). The ball launches at a greater launch angle and initial velocity upon driver full shots at low head speed, traveling a longer distance.

Abstract: A golf ball is prepared by forming a cover of two layer structure consisting of an inner layer and a thin outer layer on a core by heat compression molding. A color difference .DELTA.E in Lab color space between the inner and outer layers is up to 3. Tracks of seams and streaks on the inner layer at the parting line are visually unperceivable, and the ball is good looking.

Abstract: The present invention provides a thread-wound golf ball comprising a thread rubber ball prepared by winding thread rubber around a spherical solid center and a cover enclosing the thread rubber ball therein, wherein the solid center satisfies the following equations (1) to (3):.alpha.=26 to 34 (mm) (1)10.0-0.25.alpha.(mm)<.beta.<13.0-0.25.alpha.(mm) (2).gamma./.alpha.<0.11 (3)where .alpha. is the diameter of the solid center, .beta. is the deformation of the solid center under a load of 30 kg at room temperature, and .gamma. is the deformation of the solid center frozen through the use of dry ice as measured 1 minute after application of a load of 50 kg to the frozen solid center at room temperature. The thread-wound golf ball has stable quality due to an undeformed solid center and provides a long travel distance through the use of a large-diameter, low-hardness solid center.

Abstract: A thread wound golf ball comprises a solid center and a wound core having a thread rubber layer formed by winding thread rubber around the center and a cover enclosing the wound core. The cover is based on a non-yellowing thermoplastic polyurethane elastomer, and the difference in specific gravity between the center and the cover is 0.2 or less.

Abstract: In a golf ball comprising a solid or wound core and a cover, the solid core or a center of the wound core is prepared by molding and vulcanizing a rubber composition comprising 100 parts by weight of base rubber and 10-120 parts by weight of a weight adjuster having a mean particle size of 30-1,000 .mu.m and a specific gravity of 4-19.1. The solid core or center is improved in restitution and the ball will fly a longer distance.

Abstract: A thread wound golf ball comprises a liquid center and a wound core having a thread rubber layer formed by winding thread rubber around the center and a cover enclosing the wound core. The cover is based on a non-yellowing thermoplastic polyurethane elastomer, and the difference in specific gravity between the center and the cover is 0.2 or less.

Abstract: A thread-wound golf ball prepared by winding thread rubber around a center, and having a two layer cover. The inner cover is made of an ionomer resin mixture or blend of ionomers having an acid content of not greater than 15 percent by weight, and a melt flow rate measured at 190.degree. C. of from 2 to 9. The outer cover is made of a resin having a hardness of 43 to 53 on the Shore D scale.

Abstract: A thread-wound golf ball comprising: a thread rubber ball prepared by winding thread rubber around a spherical center, and a cover enclosing the thread rubber ball therewith, which golf ball has a deformation under a load of 100 kg of from 2.5 to 3.7 mm, and wherein the center has an intrinsic frequency of from 2,000 to 4,000 Hz, an outer diameter of from 31 to 35 mm, a deformation under a load of 30 kg in the range of 1.2 to 2.6 mm, and a weight of from 19.5 to 29.0 g.

Abstract: The present invention provides a thread-wound golf ball comprising a thread rubber ball prepared by winding thread rubber around a spherical solid center, and a cover enclosing the thread rubber ball therewith, which has a number of dimples of from 350 to 500 and a dimple volume rate of 0.76 to 0.9 percent, and wherein the solid center has an outer diameter of from 27 to 38 mm, a deformation under a load of 30 Kg of from 1.5 to 3.5 mm and a rebound, when dropped from a height of 120 cm, of at least 96 cm. The thread-wound golf balls of the present invention show good spin properties in addition to good restitution properties, resulting in improved travel distance.