Abstract: The present invention provides a resin composition for a golf ball and a golf ball which have high resilience while maintaining soft compression and also have low spin on driver shots, and therefore can achieve a long flight distance. The present invention relates to a resin composition for a golf ball, including an ionomer resin consisting of a metal ion-neutralized copolymer of (A) a C3-8 ?,?-unsaturated carboxylic acid and (B) a C3-8 ?,?-unsaturated carboxylic acid ester, the ionomer resin having a mass ratio of (A)/(B) of 10/90 to 25/75, and a degree of neutralization of 30 to 105 mol %.

Abstract: An object of the present invention is to provide a golf ball that decrease the spin rate on the driver shots while suppressing the decrease in the spin rate on the approach shots in a golf ball having a urethane cover. The present invention provides a golf ball having a core consisting of a center and at least one intermediate layer covering the center, and a cover covering the core, wherein the cover contains polyurethane, and has a slab hardness of 85 or less in JIS A hardness, the core has a surface hardness of 60 or more in Shore D hardness, the intermediate layer has a thickness ranging from 0.5 mm to 2.0 mm, and a resin component constituting the intermediate layer has a hardness from 62 to 68 in Shore D hardness, a flexural modulus from 300 MPa to 500 MPa, and a maximum storage modulus E? between ?30° C. to 0° C. ranging from 1,000 MPa to 2,000 MPa.

Abstract: A golf ball 2 includes a core 4, a mid layer 6, a reinforcing layer 8, and a cover 10. A hardness Hm of the mid layer 6 is greater than a hardness Hc of the cover 10. A difference (Hm?Hc) is greater than 28. A hardness Hs2 at a surface of a sphere consisting of the core 4 and the mid layer 6 is greater than a hardness Hs3 at a surface of the golf ball 2. A difference (Hs2?Hs3) is less than 5. A thickness Tm of the mid layer 6 is larger than a thickness Tc of the cover 10. A ratio (Tm/Tc) is greater than 3.0 and less than 5.0. A diameter of the core 4 is equal to or greater than 38.2 mm. The hardness Hc of the cover 10 is equal to or less than 37.

Abstract: A high performance golf ball includes a resin inner core, a rubber outer core, and a cover. The resin inner core is made of highly neutralized polymer, and may include a blend of different highly neutralized polymers. The cover is a two layer cover, with a hard inner cover and a thermoplastic polyurethane outer cover. The ball as a whole has properties to maximize performance and aesthetic properties, such as feel and sound.

Abstract: A golf ball having certain relationships and values of its initial velocities at various club head speeds is provided. The golf ball has a typical initial velocity at a low club head speed, but an increased initial velocity at a high club head speed. Therefore, the golf ball may be advantageously used by both amateur golfers having lower swing speeds and professional golfers having high swing speeds. The golf ball may also achieve an initial velocity of at least about 173 mph at a club head speed of about 125 mph, therefore achieving an increased total shot distance.

Abstract: A golf ball comprises (a) a core, (b) an inner mantle layer, (c) an intermediate mantle layer, (d) an outer mantle layer and (e) at least one cover layer, and the material flexural modulus (FM) of the core and the various layers follows the relationship FM(core)<FM(inner mantle)>FM(intermediate)<FM(outer mantle)>FM(cover), or the relationship FM(core)<FM(inner mantle)<FM(intermediate)>FM(outer mantle)>FM(cover).

Abstract: An object of the present invention is to provide a golf ball which travels a great distance on the driver shots and stops quickly on the green on the approach shots. The present invention is directed to a golf ball material having a shear loss modulus G? of 2.11×107 Pa or less, and a ratio (E?/G?) of a tensile loss modulus E? to the shear loss modulus G? of 1.78 or more, when measuring the shear loss modulus G? in a shear mode and the tensile loss modulus E? in a tensile mode at conditions of a temperature of 0° C., oscillation frequency of 10 Hz using a dynamic viscoelasticity measuring apparatus.

Abstract: A golf ball comprising: an inner core formed from a first substantially homogenous rubber composition comprising a carbon-carbon initiator, the inner core having a geometric center and a first outer surface having a hardness less than that of the geometric center by up to about 20 Shore C; an outer core layer disposed about the inner core formed from a second substantially homogenous rubber composition and comprising a second outer surface having a hardness that is up to about 43 Shore C points greater than the hardness of the geometric center; an inner cover layer disposed about the core comprising an ionomeric material and having a material hardness of about 55 Shore D or greater; an outer cover layer disposed about the inner cover layer comprising a polyurea or polyurethane and having a material hardness of 20 Shore D to 70 Shore D.

Abstract: Multi-layered golf balls containing a two or three-layered cover assembly are provided. In one embodiment, the cover assembly includes a relatively hard inner cover and relatively soft outer cover. Alternatively, the cover assembly may include a relatively soft inner cover with a relatively hard outer cover. Three-layered covers comprising an inner cover, intermediate cover, and outer cover layer also may be prepared. Preferably, at least one of the layers is formed from a thermoplastic composition that preferably comprises: a) ethylene acid copolymer, b) plasticizer, and c) cation source. A fatty acid ester such as ethyl oleate is preferably used as the plasticizer. The cover assembly has good impact durability and helps provide the ball with relatively high resiliency at given compressions.

Abstract: A golf ball 2 includes a spherical core 4 and a cover 6 positioned outside the core 4. The golf ball 2 further has dimples 8 on a surface thereof. The core 4 is obtained by crosslinking a rubber composition. The difference between a hardness H(5.0) at a point that is located at a distance of 5 mm from the central point of the core 4, and a hardness Ho at the central point is equal to or greater than 6.0. The difference between a hardness H(12.5) at a point that is located at a distance of 12.5 mm from the central point, and the hardness H(5.0) is equal to or less than 4.0. The difference between a hardness Hs at the surface of the core 4 and the hardness H(12.5) is equal to or greater than 10.0. The difference between the hardness Hs and the hardness Ho is equal to or greater than 22.0. There is no zone in which a hardness decreases from the central point to the surface. The rubber composition of the core 4 includes 2-naphthalenethiol. A cross-sectional shape of each dimple 8 is a wave-like curve.

Abstract: A high performance golf ball includes a resin inner core, a rubber outer core, and a cover. The resin inner core is made of a blend of highly neutralized polymers and a low flexural modulus ionomer, and may include a blend of different highly neutralized polymers. The inner core has a specified relationship of coefficients of restitution of the various layers of the ball. The cover is a single layer ionomer cover, and may be made from a blend of different grades of the ionomer. The ball as a whole has properties to maximize performance and aesthetic properties, such as backspin off the irons, feel, and sound.

Abstract: A method of recycling a multi-material inner part of a golf ball includes a variety of steps. The inner part and cover are separated from one another. The inner part is pulverized into pieces. The pieces are placed in a liquid to separate the pieces of one material from the pieces of the other materials. A ball designed for use in such a system is also disclosed.

Abstract: A golf ball having a cover material made from a polyurea or polyurea/urethane hybrid composition is provided. The polyurea or polyurea/urethane composition is produced by the reaction of an isocyanate blend having an average NCO functionality in the range of 2.05 to 2.35, a polyamine compound, and amine or hydroxyl curing agent. The resulting cover material has many advantages including improved thermal-stability, durability, toughness, and cut/tear-resistance. The preferred isocyanates in the blend include isophorone diisocyanate (“IPDI”); 1,6-hexamethylene diisocyanate (“HDI”); 4,4?-dicyclohexylmethane diisocyanate (“H12 MDI”); 4,4?-diphenylmethane diisocyanate (4,4?-MDI); toluene diisocyanate (“TDI”); and homopolymers and copolymers thereof.

Abstract: A multi-layer golf ball includes a core, and intermediate layer, and a cover. The core has an outer surface that includes a plurality of depressions extending from a spherical land portion. Each depression has a maximum depth relative to the spherical land portion of between 0.15 mm and 2.0 mm. The intermediate layer surrounds the core and has a radially inward surface that is flush with the outer surface of the core. The cover layer surrounds the intermediate layer and defines an outermost portion of ball.

Abstract: A multi-layer golf ball includes a core, an intermediate layer surrounding the core, and a cover layer surrounding the intermediate layer. The core defines an outer surface that includes a plurality of polygonal land potions substantially aligned on a common sphere, which has a diameter of between 22 mm and 32 mm. The intermediate layer has a radially inward-facing surface that is flush with the outer surface of the core, and has a radial thickness of between 4 mm and 9 mm. The outer surface of the core defines a first set of annular grooves disposed about a first axis, and a second set of annular grooves disposed about a second axis. Each of the first and second set of annular grooves extend radially inward from the common sphere, and the first axis and the second axis are orthogonal.

Abstract: A multi-layer golf ball includes a core having an outer surface, and intermediate layer surrounding the core, and a cover surrounding the intermediate layer. The intermediate layer defines a radially inward facing surface that is flush with the outer surface of the core, and the cover defines the outermost surface of ball. The outer surface of the core includes a plurality of polygonal land portions aligned on a common sphere. The outer surface of the core further defines a first plurality of annular grooves disposed about a first axis, a second plurality of annular grooves disposed about a second axis, and a third plurality of annular grooves disposed about a third axis. The first axis, the second axis, and the third axis are mutually orthogonal, and each groove respectively extends from the common sphere and is concave relative to the core.

Abstract: The invention provides a solid golf ball having a core and a cover. The core is formed of a rubber composition containing a base rubber, a co-crosslinking agent, a crosslinking initiator and a metal oxide. The base rubber contains polybutadiene, a styrene-butadiene rubber and, optionally, an isoprene rubber. The co-crosslinking agent is methacrylic acid, and the rubber composition includes a specific waste material in the form of a powder. The core deflection and the cover material are optimized. Utilizing a waste material in a solid golf ball conserves resources and thus is beneficial to the global environment. Even during prolonged use, the golf ball maintains its basic performance attributes (feel, flight, durability) at a high level.

Abstract: A center of a golf ball is formed from a composition having a flexural modulus from 150-450 MPa, a maximum loss factor (tan ?) between ?20 and 0° C. of 0.08 or less, a rebound resilience of 55% or more, and a slab hardness ranging from 40-60 in Shore D hardness. The center composition includes, as a resin component, 30 to 70 mass % of (A) a modified polyester elastomer having a Shore A hardness of 95 or less; 70-30 mass % of (B) a binary ionomer resin having a Shore D hardness of 65 or more, a flexural modulus of 300 MPa or more, and a melt flow rate (190° C., 2.16 kg) of 1.0 g/10 min or more; and 0-50 mass % of (C) a thermoplastic resin other than (A) and (B) components (provided that a total content of (A), (B), and (C) components is 100 mass %).

Abstract: Method of making a golf ball. A blend of a first highly neutralized acid polymer, a second highly neutralized acid polymer, and an ionomer-based masterbatch comprising an ionomer resin and an additive is used to form a layer of a golf ball. A second layer that essentially encloses the blend-containing layer then is formed.

Abstract: A high performance golf ball includes a resin inner core, a rubber outer core, and a cover. The resin inner core is made of highly neutralized polymer, and may include a blend of different highly neutralized polymers. The cover is a two layer cover, with a hard inner cover and a thermoplastic polyurethane outer cover. The ball as a whole has properties to maximize performance and aesthetic properties, such as feel and sound.

Abstract: A golf ball core for use in a multi-piece golf ball includes a solid sphere and between 100 and 300 spaced polygonal protrusions extending from the solid sphere in a radially outward direction. The sphere is substantially formed from an ionomeric material, and has a diameter (D) of between 24 mm and 32 mm. The polygonal protrusions extend from the sphere by a maximum distance of between 0.15 mm and 1.0 mm.

Abstract: The invention is directed to a method of making a neutralized non-ionomeric polymer composition (NNIPC) suitable for use in a golf ball component comprising the steps of: providing a non-acid copolymer composition (NACC); soaking the NACC in an organic acid to form a soaked non-acid copolymer composition (SNACC); providing a cation source in an amount sufficient to neutralize at least a portion of the organic acid; and melt processing the SNACC and cation source to form the NNIPC. The invention also relates to a method of making a golf ball incorporating the NNIPC made according to the inventive method and to the resulting golf ball.

Abstract: A golf ball having a core that includes an aqueous solution contained by a boundary layer with a solid center suspended in the solution to modify the moment of inertia of the golf ball. The aqueous solution can be thixotropic, or rheopectic, or dilatant, or pseudoplastic in nature and the center formulated to simulate the specific gravity of the solution.

Abstract: Multi-piece golf balls containing a core of at least one layer and cover of at least one layer are provided. At least one component is formed from a rubber composition comprising: i) about 10 to about 65 weight percent of a cycloalkene rubber having a trans-content of about 55% or greater and a melting point of 30° C. or greater; ii) about 30 to about 80 weight percent of an ionomeric resin; and 3) about 5 to about 40 weight percent of a polyamide. The rubber composition may further include other thermoplastic and thermosetting materials such as, for example, polybutadiene, polyisoprene, ethylene propylene rubber, ethylene propylene diene rubber, and styrene-butadiene rubber. The rubber composition helps improve resiliency, durability, scuff-resistance, and feel of the ball.

Abstract: Embodiments of the disclosed polymer composition comprise a first unsaturated polymer or polymer precursor, and an effective amount of a peptizer. The peptizer typically comprises a heteroaryl or a heterocyclic compound, other than morpholine as disclosed in assignee's prior applications. Disclosed polymer compositions are useful for making sports equipment, such as at least one layer of a golf ball, often a core. Because the compositions are useful for making golf balls, materials commonly known for making such golf balls can be used in combination with the polymer composition. A method for forming a golf ball also is disclosed. The method comprises providing disclosed compositions and then forming at least one component of a golf using the composition.

Abstract: Multi-piece golf balls containing a dual-core structure are provided. The core structure includes an inner core (center) comprising a foam composition, preferably foamed polyurethane. The outer core layer is preferably formed from a non-foamed thermoplastic composition such as ethylene acid copolymer ionomer. Preferably, the specific gravity (density) of the foam inner core is less than the density of the outer core layer. The ball further includes a cover of at least one layer and may include at least one casing layer. The core structure and resulting ball have relatively good resiliency.

Abstract: The invention provides a solid golf ball having a core and a cover. The core is formed of a rubber composition containing a base rubber, a co-crosslinking agent, a crosslinking initiator and a metal oxide. The co-crosslinking agent is methacrylic acid, and the rubber composition includes a specific waste material in the form of a powder. The core deflection and the cover material are optimized. Utilizing a waste material in a solid golf ball conserves resources and thus is beneficial to the global environment. Even during prolonged use, the golf ball maintains its basic performance attributes (feel, flight, durability) at a high level.

Abstract: An object of the present invention is to provide a golf ball having high resilience. The present invention provides a golf ball having a constituting member, wherein at least a part of the constituting member is formed from a rubber composition containing (a) a base rubber, (b) a co-crosslinking agent, (c) a crosslinking initiator, and (d) an organic sulfur compound, the organic sulfur compound being derivatives of thiophenols and disulfide with a strong electron withdrawing substituent.

Abstract: A golf ball includes a core and a cover surrounding the core. The cover includes a first hemispherical half and a second hemispherical half that define a seam line therebetween and along an outer surface of the cover. The seam line is non-planar and includes an integral number of cycles of a repeating wave that oscillates along the outer surface of the cover. Each cycle of the repeating wave has a 2? radian phase, and an intermediate section is interleaved within the repeating wave at phase angles that are integral multiples of ?. Each intermediate section has a straight surface profile along the outer spherical surface.

Abstract: A method for manufacturing a golf ball showing a great flight distance on driver shots for includes the steps of: preparing a rubber composition containing a base rubber, an ?,?-unsaturated carboxylic acid having 3 to 8 carbon atoms and/or a metal salt thereof as a co-crosslinking agent, a crosslinking initiator and a carboxylic acid and/or a salt thereof; heat pressing the rubber composition at a press temperature ranging from t-40° C. to t-15° C. to mold a spherical core, wherein t ° C. is a one-minute half-life temperature of the crosslinking initiator; and forming at least one cover layer covering the spherical core.

Abstract: A golf ball includes a core and a cover surrounding the core. The cover includes a first hemispherical half and a second hemispherical half that define a seam line therebetween and along an outer surface of the cover. The seam line is non-planar and includes a repeating trapezoidal wave having a first portion disposed at a first latitude, a second portion disposed at a second latitude, and a linear ramping transition between the first portion and the second portion. The seam line further includes a first curvilinear wave superposed within the first portion of the trapezoidal wave, and a second curvilinear wave superposed within the second portion of the trapezoidal wave.

Abstract: An object of the present invention is to provide a golf ball showing a great flight distance on driver shots. The present invention provides a golf ball comprising a spherical core and at least one cover layer covering the spherical core, wherein when JIS-C hardness of the spherical core is measured at points located at distances of 0% (core center), 37.5%, 75.0% and 100% (core surface) from the core center of the spherical core, a hardness difference (Hs?Ho) between a surface hardness (Hs) thereof and a center hardness (Ho) thereof is 20 or more, a ratio ((H37.5?Ho)/(H75.0?Ho)) of a hardness difference (H37.5?Ho) to a hardness difference (H75.0?Ho) is 0.6 or less, and a compression deformation amount (D (mm)) of the spherical core and the 37.5% point hardness (H37.5) satisfy a relation of H37.5??9×D+95.

Abstract: A golf ball 2 includes a core 4, a mid layer 6, and a cover 8. The core 4 includes a center 10 and an envelope layer 12. The ratio (Do/De) of an amount of compressive deformation Do of the center 10 to an amount of compressive deformation De of the core 4 is equal to or greater than 1.5 but equal to or less than 2.5. The ratio (Do/Dc) of the amount of compressive deformation Do of the center 10 to an amount of compressive deformation Dc of the golf ball 2 is equal to or greater than 1.8. The diameter of the center 10 is equal to or less than 20 mm. The difference (He?Ho) between a surface hardness He of the core 4 and a central hardness Ho of the center 10 is equal to or less than 40.

Abstract: An object of the present invention is to provide a golf ball having high resilience. The gist of the present invention resides in selecting an organic sulfur compound used for a golf ball rubber composition containing (a) a base rubber, (b) a co-crosslinking agent, (c) a crosslinking initiator, and (d) the organic sulfur compound from organic sulfur compounds having specific structures such that a sum of substituent constants of the substituents X in a structure represented by the following formula (4) is 0.2 or more and SP value of the structure represented by the following formula (4) is in a range from 19.0 (J/cm3)1/2 to 24.0 (J/cm3)1/2 and using the same.

Abstract: The present invention provides a golf ball that achieves a low spin rate on driver shots to thereby improve flight distance performance, and also has improved durability, especially at high clubhead speeds. The present invention relates to a golf ball including a core, at least one middle layer covering the core, and a cover covering the middle layer, wherein at least one piece or layer of the middle layer includes a material for a middle layer that includes a thermoplastic polyurethane with a slab hardness of 65 to 80 in Shore D hardness and a ratio of upper yield stress (MPa) to lower yield stress (MPa) of not more than 1.60.

Abstract: A golf ball that includes (a) a core comprising a center; (b) an outer cover layer; and (c) one or more intermediate layers; wherein at least one of the core, the outer cover layer, or the intermediate layer comprises a composition that includes (i) at least one polyalkenamer and at least one polyamide or (ii) at least one polyalkenamer. A method for making a golf ball comprising a core, one or more intermediate layers and an outer cover layer is also disclosed, wherein the method includes forming a blend comprising at least one polyalkenamer rubber and at least one polyamide; and injection molding the blend into a spherical mold to form the intermediate or outer cover layer. Also disclosed is a polymer composition that includes at least one polyalkenamer and at least one thermoplastic copolyamide elastomer.

Abstract: The “Novelty Square Golf Ball” is intended as a novelty item, having the same weight and approximate proportional dimensions with a plurality of dimples on the outer covering, resembling an ordinary spherical golf ball. The “Novelty Square Golf Ball” will be a cube in physical nature. The “Novelty Square Golf Ball” will resemble an ordinary golf ball in all aspects except for its unique cube shape, and unlike an ordinary golf ball, the “Novelty Square Golf Ball” solid core materials will not be of consequence to the final product or its performance. The “Novelty Square Golf Ball” is not intended for use in a game of golf, or any other challenge. The “Novelty Square Golf Ball” will appear white in overall color, but may be produced in a variety of colors. The “Novelty Square Golf Ball” may have one or more graphics, logos and/or text messages imprinted on the outer cover.

Abstract: Golf balls having a core comprising a polyalkenamer rubber composition are provided. The rubber composition may further include other rubbers such as, for example, polybutadiene, polyisoprene, ethylene propylene rubber, ethylene propylene diene rubber, and styrene-butadiene rubber. The rubber composition helps improve resiliency of the core and provides the ball with a comfortable and soft feel. In one version, a solid, single core having an outer surface and geometric center is provided, wherein the outer surface has a hardness greater than the hardness of the geometric center to define a positive hardness gradient of at least 10 Shore C. In a second version, a dual-core having an inner core and surrounding outer core layer is provided. The inner core has a positive hardness gradient, while the outer core has a zero; negative; or positive hardness gradient.

Abstract: Disclosed herein are heterogeneous golf ball compositions comprising a matrix formed from a thermosetting polymer composition and discrete particles of crosslinked rubber dispersed within the matrix.

Abstract: The present invention discloses a two piece golf ball having a core and an outer cover layer; where the core includes a modifier which is either a block copolymer having a number average molecular weight of from about 30,000 to about 300,000 composed of at least two blocks including aromatic vinyl units each having a number average molecular weight of about 2,500 to about 40,000 and at least one block containing a vinyl bond content of not less than about 40%, and having a peak temperature of primary dispersion of tan ? of at least 0° C., and consisting of isoprene or isoprene-butadiene units; or from about 1 to about 50 parts by weight of a triallyl-cyanurate; or a combination of the block copolymer and the triallylcyanurate.

Abstract: The invention provides a golf ball having a core encased by a cover of one or more layer, which cover is formed of a material composed primarily of a thermoplastic polyurethane material and containing also a lubricant composed primarily of a montanic acid ester. Paint film adhesion is not adversely affected even when the mold temperature during injection-molding of the golf ball is raised to 60° C. or above.

Abstract: The present invention relates to a golf ball including a core, one or more mantle layers and an outer cover layer, and one or more of the core, one or more mantle layers or outer cover layer includes a partially hydrogenated polybutadiene having a viscosity at 200° C. of less than about 5,000 Pa-sec and a storage modulus (G?) at 1 Hz and 25° C. of greater than about 1×107dyn/cm2.

Abstract: A golf ball comprising a silicone composition and a method for making the golf ball by liquid injection molding.

Abstract: This invention pertains to a golf ball which includes a core, optionally one or more intermediate layers; and an outer cover layer, and where one or more of the outer cover or intermediate layers includes a high acid carboxylated elastomer composition, which has an elastomer backbone and one or more carboxy and which is the reaction product of a carboxylated elastomer and an amine containing compound.

Abstract: A golf ball of a first color is dyed to a second color with an anionic or nonionic disperse dye. Either or both of the cover or an optional clear coating layer on the cover comprises a member selected from the group consisting of polyurethanes, polyureas, polyamides, and combinations thereof, which can be dyed by the anionic or nonionic disperse dye.

Abstract: The present invention provides a multi-piece solid golf ball having a core, an envelope layer encasing the core, an intermediate layer encasing the envelope layer, and a cover which encases the intermediate layer and has, on a surface thereof a plurality of dimples. The envelope layer has an inner layer and an outer layer. The core is formed primarily of a rubber material. The inner and outer envelope layers, the intermediate layer and the cover are each formed primarily of the same or different resin materials. The inner and outer envelope layers, intermediate layer and cover have thicknesses and hardness values which satisfy particular specified inequalities and which occupy particular specified ranges. The golf ball has an outstanding flight performance and controllability which are acceptable to professionals and other skilled players, in addition to which it has an excellent durability to cracking under repeated impact and an excellent scuff resistance.

Abstract: The invention provides a rubber composition for golf balls which includes (A) a base rubber containing a polybutadiene having a cis-1,4 bond content of at least 60 wt %, (B) an unsaturated carboxylic acid and/or a metal salt thereof, and (C) a diphenylamine of the general formula wherein R1 and R2 are each independently a hydrogen atom or a hydrocarbon group of 1 to 20 carbons, m is an integer from 1 to 5, and n is an integer from 1 to 4, with the proviso that if m and/or n is 2 or more, each occurrence of R1 and R2 may be the same or different. The golf ball rubber composition of the invention enables a high-quality molded and crosslinked product having a suitable hardness and a high resilience to be obtained.

Abstract: Golf balls having cores with negative hardness gradients are provided. The cores are made of polyalkenamer rubber compositions that may further include other rubbers such as, for example, polybutadiene, polyisoprene, ethylene propylene rubber, ethylene propylene diene rubber, and styrene-butadiene rubber. In one version, a solid, single core having an outer surface and center is provided, wherein the outer surface has a hardness substantially the same or lower than the hardness of the center to define a zero or negative hardness gradient. Dual-cores having inner and outer cores can be made, wherein the inner core has a negative hardness gradient and the outer core has a positive or negative hardness gradient. The rubber composition helps improve resiliency of the core and provides the ball with a comfortable and soft feel.

Abstract: A golf ball comprising: (a) a core; (b) an inner mantle layer; (c) an intermediate mantle layer; (d) an outer mantle layer; and (e) at least one cover layer; wherein the core has a PGA compression of less than 70, and the core/inner mantle layer/intermediate mantle layer combined construct has a PGA compression of at least 30.

Abstract: A golf ball 2 includes a core 4, a mid layer 6, and a cover 8. The core 4 includes a center 10 and an envelope layer 12. The ratio of the volume Ve of the core 4 to the volume of a phantom sphere of the golf ball 2 is equal to greater than 76%. The ratio (Co/Do) of an amount of compressive deformation Co of the center 10 to the diameter Do of the center 10 is equal to or greater than 0.085 but equal to or less than 0.130. The ratio (Ce/De) of an amount of compressive deformation Ce of the core 4 to the diameter De of the core 4 is equal to or greater than 0.015 but equal to or less than 0.020.