Abstract: In a wound golf ball comprising a solid center, a thread rubber layer, and a cover, the solid center has a diameter of 29-37 mm, has such a hardness distribution that the hardness at the outer surface is lower than the hardness at a middle and the difference between the maximum and the minimum of solid center hardness is at least 6 units on JIS-C hardness scale, has a JIS-C hardness of 50-85 at the outer surface, and experiences a deformation of 2-4.5 mm under a 1-50 kg load. The ball exhibits an optimum spin performance when hit with different types of clubs, and affords improved feel, durability, and distance.

Abstract: A thread-wound golf ball includes a solid center, a rubber thread layer wound around the surface of the solid center, and a cover enveloping the surface of the rubber thread layer, the cover having dimples formed thereon. An amount of deformation of the solid center under a load of 9.8 N-294 N is 1.0-1.5 mm. A difference between the diameter A1 of the solid center and the thickness A2 of the rubber thread layer represented by (A1−A2) is 34.5-36.5 mm. The cover has a Shore D hardness of 44-58. Dimple volume ratio Rv and the difference between the diameter of the solid center and the thickness of the rubber thread layer represented by (A1−A2) satisfy a relation: 24.5≦(A1−A2)×Rv≦29.0.

Abstract: A thread-wound golf ball, such as a balata-covered golf ball, formed of a center 1a, a rubber thread layer 1b covering the center 1a, and a cover 2 is provided. The center 1a has an outer diameter of 28-35 mm and a Shore A hardness of 10-50. The cover 2 is formed of a mixture containing ionomer resin, thermoplastic elastomer and tackifier and has a Shore D hardness of 45-60. As such, the golf ball exhibits great carry distance with good shot feel, provides high spin rate when shot from the rough or in a raining condition, and that easily comes to a halt.

Abstract: The present invention is directed towards an improved golf ball that includes a high-specific gravity central sphere encapsulated in a soft and resilient shell layer. The soft-resilient shell may be formed of polybutadiene rubber. This shell is subsequently wound with thread a wound core, which is then covered. The sphere can be formed of a solid metal or molded of high-specific gravity powder retained in a binding material.

Abstract: A wound golf ball comprising a center, a cover, and at least one wound layer disposed between the center and the cover, wherein the at least one wound layer is formed of a tensioned elastomeric thread having at least one ply, wound about the center with a tension of less than about 700 g, and wherein the center has a first deformation value, formed by applying a load to the center within the range from an initial load of 10 kg to a final load of 130 kg, and the golf ball has a second deformation value, formed by applying a load to the golf ball within the range from an initial load of 10 kg to a final load of 130 kg, such that a difference between the second deformation and the first deformation is less than 0.4 mm.

Abstract: The present invention provides a solid center type thread wound golf ball having long flight distance, while having good shot feel at the time of hitting the golf ball as good as liquid center type thread wound golf balls. The present invention thus provides a thread wound golf ball comprising a solid center, a thread rubber layer formed on the solid center, and a cover covering the thread rubber layer wherein, the solid center has a diameter of 33 to 38 mm, a ratio of surface hardness in JIS-C hardness to diameter of 2.15 to 2.50, and a ratio of center hardness in JIS-C hardness to diameter of 1.30 to 2.00, and the cover has a Shore D hardness of 40 to 65. Further, the solid center of the thread wound golf ball has a center hardness in JIS-C hardness of 50-75, and a surface hardness larger than the center hardness by not less than 10, and the thread rubber layer has a thickness of 1.0 to 4.0 mm.

Abstract: A wound golf ball that includes a wound core surrounded by a cover, wherein the wound layer is at least partially impregnated with a thermoplastic or thermoset material. The wound core is formed of a fluid-filled or solid center, and at least one wound layer surrounding the center.

Abstract: The invention includes a golf ball having a core, a hoop-stress layer of high tensile elastic modulus material wrapped or wound about the core, at least one outermost layer of a thermoset material having a thickness of greater than about 0.065 inches. A binding material can be used in conjunction with the hoop-stress layer to facilitate positioning of the hoop-stress layer around the core for easier manufacturing.

Abstract: The present invention is directed to a golf ball comprising a solid core component that includes a relatively hard central portion and a relatively soft skin portion surrounding the central portion. Various preferred embodiment golf balls are disclosed utilizing this core configuration. A golf ball comprising the noted core component having a wound layer disposed about the core skin portion is described. Another preferred embodiment relates to the use of the noted core component having a multi-layer cover assembly surrounding the core. Various methods for producing such golf ball core components are disclosed.

Abstract: A low compression, resilient golf ball having a center and a cover, made from a polybutadiene reaction product having polybutadiene, a cis-to-trans catalyst including an organosulfur component, and a free radical source. The reaction product has a first dynamic stiffness measured at −50° C. that is less than about 130 percent of a second dynamic stiffness measured at 0° C. A multi-layer golf ball having a center, at least one intermediate layer disposed concentrically about the center, and a cover. At least a portion of at least one of the center, intermediate layer, or both, are made from a reaction product including polybutadiene having a cis-to-trans catalyst that includes at least one organosulfur component and a free radical source. The reaction product has a first dynamic stiffness measured at −50° C. that is less than about 130 percent of a second dynamic stiffness measured at 0° C.

Abstract: A low compression, resilient golf ball having a center and a cover, made from a polybutadiene reaction product having polybutadiene, a cis-to-trans catalyst including a Group VIA element, such as at least one of sulfur, polymeric sulfur, selenium, or tellurium, and a free radical source. The reaction product typically has a first dynamic stiffness measured at −50° C. that is less than about 130 percent of a second dynamic stiffness measured at 0° C. A multi-layer golf ball having a center, at least one intermediate layer disposed concentrically about the center, and a cover. At least a portion of at least one of the center, intermediate layer, or both, are made from a reaction product including polybutadiene having a cis-to-trans catalyst that includes at least one elemental sulfur, polymeric sulfur, selenium, or tellurium component and a free radical source.

Abstract: A multi-layer golf ball can be prepared, possessing the performance characteristics of both a solid ball and a wound ball, by selecting the content and thickness of one or more of the layers, wherein the multi-layer golf ball comprises a center, an intermediate layer, a wound layer of tensioned material, and a cover, such that any one or more of the following are satisfied: (a) at least a portion of the intermediate layer includes a thermoset material; (b) the winding includes fiber, glass, carbon, polyether urea, polyether block copolymers, polyester urea, polyester block copolymers, isotactic-poly(propylene), polyethylene, polyamide, poly(oxymethylene), polyketone, poly(ethylene terephthalate), poly(p-phenylene terephthalamide), poly(acrylonitrile), diaminodicyclohexylmethane, dodecanedicarboxylic acid, or copolymers or combinations thereof; (c) the thickness of the wound layer is less than about 1 mm; and (d) at least a portion of the cover includes a thermoset material.

Abstract: A golf ball core incorporates a cobalt-catalyzed polybutadiene rubber falling within particular specifications for various material values. The material allows for manufacture of a core having a desirable coefficient of restitution and compression properties, while also exhibiting ease of processing. The core also can incorporate a high-cis content, high viscosity polybutadiene rubber to further enhance its coefficient of restitution and compression properties, while maintaining good ease of processing.

Abstract: The disclosed invention provides a golf ball comprising a core and a cover, wherein at least one of the cover or the core is formed from a polymer blend comprising at least one grafted metallocene-catalyzed polymer, at least one ionomer, and at least one non-ionomer having improved melt flow characteristics.

Abstract: The present invention describes a golf ball with a center, at least one wound layer, optionally, at least one intermediate layer, and at least one cover layer. The center is at least about 1 inch in diameter and includes polybutadiene, natural rubber, polyisoprene, styrene-butadiene, or styrene-propylene-diene rubber. The at least one wound layer includes one or more of polyether urea, polyester urea, polyester block copolymers, polyethylene, polyamide, polyketon, poly (p-phenylene terephthalamide), or polyisoprene. The at least one intermediate layer includes polybutadiene, natural rubber, polyisoprene, styrene-butadiene, or styrene-propylene-diene rubber. The at least one cover layer includes a thermoplastic resin or a thermoset material. This unique construction gives the ball characteristics both of a wound and a solid construction.

Abstract: A four-piece golf ball is disclosed herein. The golf ball has a core with an oxygen barrier boundary layer, a wound layer and a polyurethane cover. The core is preferably composed of polybutadiene material. The boundary layer is preferably composed of a blend of ionomers. The cover is preferably composed of a thermosetting polyurethane material. The golf ball has exceptional distance, exceptional feel and exceptional durability.

Abstract: A thread-wound golf ball is provided including a core, a rubber thread layer surrounding the core, and a cover formed of a mixture of ionomer resin, thermoplastic elastomer and a tackifier, having a Shore D hardness of at least 40 and not more than 65.

Abstract: In a thread-wound golf ball including a center ball, a thread layer, and a cover, the thread layer is formed of rubber thread and resin thread mixedly wound around the center ball. The resin thread wound around the center ball together with the rubber thread is preferably formed of a resin (such as polyester resin or polyurethane resin) which has relatively high resilience and is softer than rubber thread undergone extension crystallization.

Abstract: Golf balls having two or more layers, one of which includes low water activity fluids, to inhibit or prevent weight loss through fluid loss, as well as methods of preparing such golf balls.

Abstract: A three-piece thread wound golf ball including a central solid core portion having increased diameter of 1.35-1.50 inch (34.3-38.1 mm) and specific gravity of 1.20-1.25, a thread-wound intermediate portion, having diameter of 1.54-1.60 inches, and an outer dimpled cover portion which construction provides desirable increased moment of inertia and spin characteristics for the ball. The resulting golf ball characteristics are such that when hit with a Driver, other woods or the longer iron club it performs like a distance two-piece golf ball, when hit with mid-iron clubs it performs like a two-piece Hi-spin golf ball and soft covered multi layered balls, and when it is struck with short iron clubs it performs much like a Balata wound golf ball.

Abstract: The present invention is directed to an improved golf ball and a method of winding that includes measuring and controlling thread stress directly, rather than maintaining and controlling the level of tension on the threads. The golf ball includes a center, a wound layer that surrounds the center to form a wound core, and a cover that surrounds the wound core. The wound layer is formed of at least one thread, and the wound layer includes a plurality of radially extending sections, each section has a thread stress. The stress within each section is substantially constant, but at least two radially extending sections have different stresses. The method for winding thread onto a golf ball center to form a wound core comprises the steps of measuring a stress within a portion of the thread; winding the thread about the golf ball center while applying a force on the thread to form a plurality of portions with predetermined thicknesses and varying the stress between the portions.

Abstract: A solid golf ball has a soft solid core and a hard cover. The cover is formed of a thermoplastic resin-base cover stock, with 11-45 parts by weight of a particulate inorganic filler added thereto per 100 parts by weight of the cover stock. The solid core undergoes a deflection of 3.0 to 5.5 mm under a load of 100 kg. The ball is drastically improved in durability against cracking.

Abstract: A thread rubber exhibiting good impact resilience in an elongated state, and a golf ball using such thread rubber are provided. The vulcanized thread rubber composition is obtained by vulcanizing a thread rubber composition including at least 50 wt % of polyisoprene rubber having a cis 1, 4 bond content of 80-95% and a trans 1, 4 bond content of 2-4% within a rubber component. In the vulcanizate, a ratio of a crosslinked density of polysulfide bonds with respect to a total crosslinked density is more than 70%. The golf ball is made using this vulcanized thread rubber composition.

Abstract: The present invention provides a thread wound golf ball having soft and good shot feel at the time of hitting, excellent durability and excellent flight performance. The present invention related to a thread wound golf ball comprising a thread wound core composed of a center and a thread rubber layer formed on the center, and a cover composed of an inner cover formed on the thread rubber layer and an outer cover formed on the inner cover, wherein the outer cover has higher hardness than the inner cover, and has a Shore D hardness of not less than 65.

Abstract: The present invention provides a thread wound golf ball having excellent rebound characteristics. The present invention relates to a thread wound golf ball comprising a solid center, a thread rubber layer formed on the solid center, and at least one layer of a cover covering the thread rubber layer, wherein the solid center comprises at least one rubber layer, the rubber layer is formed from a rubber composition comprising a polybutadiene mixture, a metal salt of an unsaturated carboxylic acid, an organic peroxide and an inorganic filler, and the polybutadiene mixture includes (a) a polybutadiene containing a cis-l,4 bond of not less than 80% and having a Mooney viscosity of 50 to 100 ML1+4(100° C.), synthesized using nickel-containing catalyst, and (b) a polybutadiene containing a cis-1,4 bond of not less than 40% and having a Mooney viscosity of 20 to 90 ML1+4(100° C.), synthesized using lanthanide-containing catalyst, a weight ratio (a)/(b) being 30/70 to 90/10.

Abstract: The present invention is directed to an improved golf ball and a method of winding that includes measuring and controlling thread stress directly, rather than maintaining and controlling the level of tension on the threads. The golf ball includes a center, a wound layer that surrounds the center to form a wound core, and a cover that surrounds the wound core. The wound layer is formed of at least one thread, and the wound layer includes a plurality of radially extending sections, each section has a thread stress. The stress within each section is substantially constant, but at least two radially extending sections have different stresses. The method for winding thread onto a golf ball center to form a wound core comprises the steps of measuring a stress within a portion of the thread; winding the thread about the golf ball center while applying a force on the thread to form a plurality of portions with predetermined thicknesses and varying the stress between the portions.

Abstract: A low compression, resilient golf ball having a center and a cover, made from a polybutadiene reaction product having polybutadiene, a cis-to-trans catalyst including an aromatic component, and a free radical source. The reaction product typically has a first dynamic stiffness measured at −50° C. that is less than about 130 percent of a second dynamic stiffness measured at 0° C. A multi-layer golf ball having a center, at least one intermediate layer disposed concentrically about the center, and a cover. At least a portion of at least one of the center, intermediate layer, or both, are made from a reaction product including polybutadiene having a cis-to-trans catalyst that includes at least one aromatic component and a free radical source.

Abstract: A wound golf ball includes a center, at least one cover layer, and at least one wound layer disposed between the center and the cover layer. The center has a two-layer shell formed of different materials, where one layer is formed of a thermoplastic material and the other layer is formed of a thermoset material. The center is filled with a fluid having a fluid volume of at least 0.5 cubic inches. In one embodiment, the thermoplastic layer is formed of a hydrophobic material so that it has a water vapor permeation rate of less than about 250 (g·mil)/(100 in2·day).

Abstract: The present invention is directed to a golf ball and to a process for forming a golf ball having at least one layer, where the layer is formed of a saponified polymer/oxa acid blend, having from about 65 to about 99 parts of at least one saponified polymer and from about 35 to 1 parts of at least one oxa acid, based on 100 parts by weight of the saponified polymer/oxa acid blend. The layer may be foamed or unfoamed, and may form at least a portion of any of the cover, the core, or a mantle layer situated between the cover and the core.

Abstract: A three-piece thread wound golf ball including a central solid core portion having increased diameter of 1.35-1.50 inch (34.3-38.1 mm) and specific gravity of 1.20-1.25, a thread-wound intermediate portion, having diameter of 1.54-1.60 inches, and an outer dimpled cover portion which construction provides desirable increased moment of inertia and spin characteristics for the ball. The resulting golf ball characteristics are such that when hit with a Driver, other woods or the longer iron club it performs like a distance two-piece golf ball, when hit with mid-iron clubs it performs like a two-piece Hi-spin golf ball and soft covered multi layered balls, and when it is struck with short iron clubs it performs much like a Balata wound golf ball.

Abstract: This invention provides a golf ball constituting or having a core layer, intermediate layer and/or cover layer consisting in whole or in part of a poly(trimethylene terephthalate) composition. The invention also provides methods for making such a ball. The compositions of the core layer, intermediate layer and/or cover layer may be foamed or unfoamed. The poly(trimethylene terephthalate) may comprise from about 1 to about 100 percent by weight of the core layer, intermediate layer and/or cover layer. In addition, the poly(trimethylene terephthalate) material may be blended with conventional materials employed to form golf ball cores, intermediate layers and/or covers.

Abstract: The present invention provides a thread wound golf ball having long flight distance, and high spin amount and excellent controllability when hitting by a short iron club, while keeping the characteristics inherent to the conventional thread wound golf ball, i.e. good shot feel. The present invention related to a thread wound golf ball comprising (a) a solid center composed of an inner center and a center outer layer formed on the inner center, (b) a thread rubber layer formed on the solid center, and (c) a cover covering the thread rubber layer, wherein the inner center has a diameter of 29 to 35 mm and a center hardness in JIS-C hardness of 30 to 70, the center outer layer has a JIS-C hardness of 70 to 90, the solid center has a diameter of 30 to 38 mm, and the cover is formed from thermoplastic resin having a Shore D hardness of 40 to 60.

Abstract: The present invention provides a golf ball exhibiting excellent shot feel, long flight distance and easy applicability of spin when hit by short irons. The golf ball comprises a thread wound core and a cover covering the thread wound core, the thread wound core comprising a solid center and a thread rubber layer formed by winding thread rubber around the solid center, wherein the solid center has a diameter of 30 to 38 mm, a surface hardness, determined by JIS-C hardness meter, of 40 to 90 and a hardness difference between the center point and the surface, determined by JIS-C hardness meter, of within 5, the solid center also has a deformation amount of 0.5 to 2.

Abstract: The invention provides a golf ball having a core, intermediate layer, cover and/or coating comprising in whole or in part of an anionic polyurethane or polyurea ionomer. The anionic polyurethane or polyurea ionomer preferably comprises a sulfonate or carboxylate group. The anionic polyurethane or polyurea ionomer may be blended with conventional materials employed to form golf balls, cores, intermediate layers and covers. The composition can be foamed or unfoamed.

Abstract: A thread-wound golf ball comprising a large, heavy center with rubber thread windings and a cover is disclosed. The center has a diameter of about between 1.40″ and 1.53″, a weight of about between 24-34 g and a deformation of about between 0.080-0.160″ when subjected to a 200 lb. load. The cover is a thermosetting or thermoplastic material with a hardness range between 40-70 Shore D. A golf ball according to the invention exhibits the combined superior characteristics of two-piece and three-piece golf balls, i.e., ease of manufacture, feel, playability, durability and distance travel.

Abstract: The present invention is directed towards a golf ball which comprises a center, at least one cover layer, and at least one layer of windings between the center and the cover. Preferably, the thread of the present invention is comprises of at least about 10 individual strands that are each about 0.01 inches in diameter. Most preferably, the thread is a solvent spun polyether urea thread manufactured by combining over 25 strands with diameters of less than about 0.002 inches. Because of the smaller thread dimension, the thread of the present invention is capable of being wound more densely than the typical thread. The elastic modulus of this thread is greater than about 20 ksi when wound about a center. The maximum elongation of the thread is greater than about 8%. The smaller cross-sectional area of the thread and higher elastic modulus of the thread also enable production of golf balls with less total thread volume.

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 wound golf ball includes a center, at least one cover layer, and at least one wound layer disposed between the center and the cover layer. At least one of the wound layers is formed of a thread composed of at least two plies of material bonded together. The first and second plies have different physical properties. The first ply is more resilient than the second ply, and the second ply is more processible than the first ply. Each ply is formed of at least about 60% synthetic rubber and less than about 40% natural rubber. The synthetic rubber is a mixture of two synthetic cis- 1,4 polyisoprene rubbers with a cis-1,4 content of at least 90%. Each ply has a different ratio of the first synthetic rubber to the second synthetic rubber, so that the plies have different physical properties.

Abstract: Ethylene/(meth)acrylic acid ionomers which have been modified with relatively low levels of a stearic acid moiety, particularly metal stearates and especially calcium stearate have improved resilience for a given level of hardness or PGA Compression values. The improvement is seen in bulk material when measurements are made on solid neat spheres. When used as cover material, the improvement is more manifest for softer material, and is less, or disappears, for typical mixed metal ionomer hard covers. The stearic-modified ionomers or ionomer blends are especially useful when the ionomer is formulated for use as a golf ball core, center, one-piece ball and as a soft golf ball cover. For covers, softer ionomer compositions will show an improvement.

Abstract: Ultraviolet radiation curing of inks on game balls, golf balls and the like is disclosed. Production inks, logo inks and methods for forming production prints and logos on golf balls, game balls and the like are disclosed. To form an ultraviolet radiation curable water-insoluble production ink, at least an adhesion promoting component is added to an ink base.

Abstract: The disclosed invention provides novel golf ball compositions which contain non-ionic olefinic copolymers produced by use of metallocene catalysts, wherein the metallocene catalyzed polymers have been functionalized with a post-polymerization reaction. The grafted metallocene catalyzed polymers may be blended with ionomers, non-grafted metallocene catalyzed polymers, or other non-ionomeric polymers. These compositions exhibit improved mechanical properties such as tensile and flexural properties, and can be foamed or unfoamed. Golf balls that employ at least one layer of these compositions in any of the golf ball cover, core, or a mantle situated between the cover and the core provide ball properties and performance similar to and in some cases better than the state of the art ionomer based golf balls.

Abstract: A golf ball having a core and/or an intermediate layer comprising a functionalized fluoropolymer wherein the fluoropolymer may be a perfluoropolymer that is sulfonated or carboxylated or a derivative thereof. The fluoropolymer material may be blended with conventional materials employed to form golf ball cores, intermediate layers, and/or covers.

Abstract: Novel golf ball compositions which contain liquid crystalline polymers and liquid crystalline polymer blends. These compositions can be foamed or unfoamed. Golf balls that employ at least one layer of these blends in any of the golf ball cover, core, or a mantle situated between the cover and the core provide ball properties and performance similar to and in some cases better than the state of the art ionomer based golf balls.

Abstract: A thread rubber for thread wound golf balls having a high impact resilience and high strength, wherein the thread rubber is obtained by vulcanizing a rubber composition which comprises (a) a rubber component selected from the group consisting of natural rubber, a synthetic high-cis-polyisoprene rubber and a mixture thereof, (b) at least one specific diaryl disulfide, (c) a vulcanizing agent, and (d) antioxidant; the compound (b) being present in an amount of 0.5 to 10 parts by weight based on 100 parts by weight of the rubber component (a).

Abstract: A golf ball constructed of a molded outer cover defining an outer diameter of the golf ball to be between 2 and 2.2 inches. One or more inner materials within the golf ball is of a sufficient density to allow the golf ball to float in water. The golf ball may comprise an inner core of a light weight material of sufficient density to allow the golf ball to float. The inner core may include a cork material. An elastic material such as elastic windings may be wrapped around the inner core. The golf ball will have the characteristics and feel of a conventional golf ball while being able to float. The increased size of the golf ball will give the beginning golfer an easier target to strike with the club face thereby improving his or her confidence in ball striking ability. The increased size will also increase the wind resistance and thereby overemphasizing balls hit with improper spin, resulting in quicker learning time. Better golfers can use this feature to practice and perfect cut and draw shots.

Abstract: A golf ball comprising a cover and core, wherein the core is formed from a blend comprising an oxa acid compound having the formula: ##STR1## wherein R is an organic moiety selected from the group consisting of alkyl, carbocyclic, and heterocyclic groups. Golf balls employing the present core blends exhibit a decreased compression without an adverse impact on the initial velocity of the ball.

Abstract: A three-piece wound golf ball having improved characteristics of moment of inertia, initial spin and total flight distance with minimal dispersion, the ball comprising:a solid center core portion which is substantially spherical, is composed mainly of polybutadiene having a core diameter of 1.35-1.50 inches (34.3-38.1 mm), a specific gravity of 1.23-1.24; and a Shore D durometer hardness of 55-75 and a compression of 59-75 on an Atti compression tester;an intermediate thread-wound portion wound with an elastomeric thread material upon the core portion to a diameter of 1.540-1.600 inches (39.1-40.6 mm), the thread having an elongation of 800-1000%, a tensile strength of 4000-5000 psi, and a rectangular cross-section configuration of 0.0625 (+/-0.002) inch .times.0.024(+/-0.

Abstract: A thread rubber for golf balls, which has good aging resistance and rebound characteristics, and to a thread wound golf ball using the thread rubber are disclosed. The thread rubber for golf balls has a retention of tensile strength after aging 7 days at 70.degree. C. of not less than 70%, a hysteresis loss at a 100 Kg/cm.sup.2 constant stress tensile of not more than 50% and an elongation at a 100 Kg/cm.sup.2 constant stress elongation within the range of 900 to 1400%.

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 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.