Abstract: Multi-layer golf balls having a hard, high compression center, a relatively soft intermediate layer, and a stiff outer cover layer, are provided. The outer surface hardness of the intermediate layer is less than that of both the center and the outer cover layer.

Abstract: A golf ball 2 includes a core 4, an inner cover 8, a mid cover 10, and an outer cover 12. Nine points are determined by dividing a region from a central point of the core 4 to a surface of the core 4 at intervals of 12.5% of a radius of the core 4. When distances (%) from the central point to the nine points and hardnesses at the nine points are plotted in a graph, R2 of a linear approximation curve obtained by a least-square method is equal to or greater than 0.95. A hardness Hi of the inner cover 8 is greater than a hardness Hs at the surface of the core 4. A hardness Ho of the outer cover 12 is greater than the hardness Hi. A difference (Hi?Hs) is 1 or greater. A difference (Ho?Hi) is 5 or greater but 30 or less.

Abstract: A first 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 mid-layer 6 includes a metal ion source (C) that can neutralize an ionomer resin. The mid-layer 6 has a melt flow rate (at 190° C. and 2.16 kg) of 4 g/10 minute or greater. The difference (H3?H1) between the JIS-C hardness H3 of the cover 8 and the JIS-C central hardness H1 of the center 10 is equal to or greater than 45. A second golf ball 22 includes a core 24, a mid-layer 28, and a cover 30. The mid-layer 28 has a melt flow rate (at 190° C. and 2.16 kg) of 4 g/10 minute or greater. Preferably, the mid-layer 28 includes a high melt viscosity resin (A), a low melt viscosity ionomer resin (B), and a metal ion source (C1).

Abstract: The invention provides a golf ball having a core and a cover of at least one layer. The cover includes an outermost layer and at least one intermediate layer interposed between the outermost layer and the core. The core has a cross-sectional hardness which, letting R (mm) be the radius of the core, A be the JIS-C hardness at the center of the core, B be the JIS-C hardness at a position R/3 mm from the core center, C be the JIS-C hardness at a position R/1.8 mm from the core center, D be the JIS-C hardness at a position R/1.5 mm from the core center, and E be the JIS-C hardness at the surface of the core, satisfies formulas (1) B?A<D?B, (2) C?A?8, and (3) E?B?15. The intermediate layer and the outermost layer have a hardness relationship therebetween which satisfies the formula “material hardness of intermediate layer?material hardness of outermost layer.

Abstract: Certain disclosed embodiments of the present invention concern a golf ball including a core having a center, an outer cover layer, and optionally one or more intermediate layers. At least one or more of the core, outer cover layer or one or more intermediate layers includes a sulfonated polyisoprene ionomer having the general formula: where A is an isoprene repeating unit having the formula —(CH2—C(CH3)?CH—CH2)—, B is an isoprene repeating unit or other monomer repeating unit, m is greater than 10, and n is greater than 2, and X is selected from one or both of the following groups; i) Li+, Na+, K+, Zn2+, Ca2+, Co2+, Ni2+, Cu2+, Pb2+, and Mg2+ or ii) an ammonium cation having the general formula [NR1R2R3R4]+. R1, R2, R3 and R4 are selected from one or both of the following hydrogen, a C1-C20 aliphatic, cycloaliphatic or aromatic moiety.

Abstract: A golf ball 2 includes a spherical core 4, an inner mid layer 6, an outer mid layer 8, a reinforcing layer 10, and a cover 12. When distances (%) from a central point of the core 4 to nine points and JIS-C hardnesses at the nine points, which nine points are obtained by dividing a region from the central point of the core 4 to a surface of the core 4 at intervals of 12.5% of a radius of the core 4, are plotted in a graph, R2 of a linear approximation curve obtained by a least-square method is equal to or greater than 0.95. Hm1 is greater than Hm2. Hc is less than Hm1. T2 is equal to or greater than 0.5 mm but equal to or less than 1.6 mm.

Abstract: Multi-piece golf balls having at least one layer made from a polyamide non-ionomeric composition are provided. The polyamide composition consist essentially of about 40 to about 99% by weight polyamide; about 1 to about 60% by weight of an acid anhydride-modified polyolefin; and about 1 to about 60% of a fatty acid additive selected from the group consisting of fatty acid salts, fatty acid amides, and mixtures thereof. The ball includes a core, preferably a dual core construction; and a cover of at least one layer. A rubber composition is preferably used to form the inner core and the polyamide composition is preferably used to form the outer core layer. The resulting ball has high resiliency along with a soft feel.

Abstract: A golf ball includes an inner core layer formed from a thermoset rubber composition. The inner core layer has a first outer surface Shore D hardness and an outer diameter of about 0.8 to 1.40 inches. A thermoplastic outer core layer is formed around the inner core layer, has a second outer surface Shore D hardness, and is formed from a copolymer of ethylene and an ?,?-unsaturated carboxylic acid, a magnesium salt of oleic acid, and sufficient cation source to fully-neutralize the acid groups of the copolymer. The golf ball includes an inner cover layer and an outer cover layer. The first outer surface Shore D hardness is greater than the second outer surface Shore D hardness and the outer core layer has a thickness of about 0.01 inches to 0.05 inches.

Abstract: The invention provides a multi-piece solid golf ball composed of a solid core, a cover, at least one intermediate layer interposed therebetween, and a plurality of dimples on a surface of the ball. The diameter of the solid core, the deflection of the core when compressed under a final load of 130 kgf from an initial load of 10 kgf, the hardness at the center of the core, the hardness in a region 5 mm to a region 10 mm from the center of the core, the hardness in a region 15 mm from the center of the core, and the surface hardness are set within specific ranges. The intermediate layer is composed primarily of a material obtained by mixing under applied heat a specific resin composition.

Abstract: The present invention is directed to a multi-layer golf ball comprising at least one core or core layer, at least one intermediate layer, and at least one cover layer. The core has a diameter of about 1.20 to about 1.56 in. and a PGA compression of about 40 to about 90. The intermediate layer comprises a modified ionomeric polymer, and it has a thickness of about 0.01 to about 0.10 in. and a Shore D hardness of about 30 to about 70. The cover layer has a Shore D hardness of about 40 to about 75. The multi-layer golf balls of the present invention provide high driver ball speed and/or a high Coefficient of Restitution, while maintaining excellent shot feel.

Abstract: A golf ball with aerodynamic coefficient magnitude and aerodynamic force angle, resulting in improved flight performance, such as increased carry and flight consistency regardless of ball orientation. In particular, the present invention is directed to a golf ball having increased flight distance as defined by a set of aerodynamic requirements, at particular spin ratios and Reynolds Numbers. The invention is also directed toward golf balls having high spin decay rates during the first second of flight that yields improved flight performance and longer ball flight.

Abstract: Multi-layer golf balls having a relatively hard outer core surrounding a relatively soft, low compression inner core are provided. The inner core generally has a compression of less than 50 and the inner core and outer core generally have a combined dual core compression of 50 or greater. The outer core generally has a Shore C hardness of 80 or greater. A cover, which can be a single-, dual-, or multi-layer cover, is provided to surround the outer core. A moisture barrier layer is optionally provided between the outer core and the cover. The moisture vapor transmission rate of the moisture barrier layer is preferably less than the moisture vapor transmission rate of the cover.

Abstract: The present invention provides a golf ball having a resilient core made of rubber, a cover of one or more layer encasing the core, and at least one intermediate layer disposed between the core and the cover, wherein the cover is made primarily of polyurethane, the intermediate layer is made primarily of ionomer, and the core has a surface hardness which is higher than the material hardnesses of the cover and the intermediate layer. The golf ball is able to limit the distance of travel more than official balls currently in use and, in spite of being a limited-distance golf ball, imparts a relatively soft and good ball feel on impact, in addition to which it has an excellent scuff resistance and, by minimizing the extent of decrease in the distance traveled by the ball when hit with an iron, minimizes the effect on golf play by amateur golfers.

Abstract: An object of the present invention is to provide a golf ball that has excellent abrasion resistance and spin performance without sacrificing the processability of the cover, in a golf ball having a cover for which a crosslinkable thermoplastic polyurethane is used as a resin component. The present invention provides a golf ball comprising: a core; and a cover covering the core, wherein the cover is formed from a cover composition containing a thermoplastic polyurethane that has, as a constituting component, a chain extender having an unsaturated carbon-carbon bond.

Abstract: Provided herein are compositions comprising an ionomer and a polyamine or a tertiary polyamide. The polyamine and the tertiary polyamide have a molecular weight of greater than 500 Da and do not contain an ester moiety or a primary amine moiety. The polyamine comprises at least three moieties that are tertiary amines or hindered secondary amines, and the polyamide comprises tertiary amide moieties and no secondary or primary amide moieties. The compositions may optionally include a filler. Further provided are articles such as golf balls and films containing these compositions.

Abstract: Multi-piece golf balls having a solid core of at least one layer and cover of at least one layer are provided. At least one of the layers is formed from a thermoplastic polyamide composition, consisting essentially of a blend of about 40 to about 99% by weight polyamide and about 1 to about 60% by weight fatty acid salt. Preferably, the ball has a dual core construction. A rubber composition is preferably used to form the inner core and the polyamide composition is preferably used to form the outer core layer. The resulting ball has high resiliency along with a soft feel.

Abstract: A ball includes a core, a cover, and an intermediate layer between the core and the cover. The intermediate layer may be deformed or actuated to create discontinuities in the cover. The creation of discontinuities allows for easier recycling of the ball parts. The intermediate layer may include one of a bladder or a hydrophilic material that expand upon the introduction of a fluid, a shape memory polymer that deforms upon application of a stimulus, or two materials that react chemically to form a gas.

Abstract: Golf balls containing a core having at least one layer and cover having at least one layer are provided. A thermoplastic ionomeric composition is used to form at least one layer of the ball. The composition is prepared by providing a masterbatch comprising cycloalkene (polyalkenamer) rubber and neutralizing agent and mixing the masterbatch with ethylene acid copolymer. The acid groups are neutralized to 30 weight percent or greater, preferably 50% or greater, and more preferably 70% or greater. The resulting ball has high resiliency and rebounding properties along with a soft feel.

Abstract: An object of the present invention is to provide a golf ball having an excellent properties like flight distance and low temperature durability. The present invention provides a golf ball comprising: a core consisting of a center and one or more intermediate layers covering the center; and a cover covering the core, wherein at least one piece or one layer of said intermediate layers is formed from a highly elastic intermediate layer composition that contains (A) a highly elastic polyamide resin having a flexural modulus in a range from 700 MPa to 5,000 MPa; (B) a metal-neutralized product of ethylene-(meth)acrylic acid copolymer and (C) a resin having a polar functional group in a specific way.

Abstract: Multi-layer golf balls having a hard, high compression center, a relatively soft intermediate layer, and a stiff outer cover layer, are provided. The outer surface hardness of the intermediate layer is less than that of both the center and the outer cover layer.

Abstract: A golf ball includes a ‘dual core’ formed from an inner core layer and an outer core layer. The inner core has an outer surface and a center and is typically formed from a substantially-homogenous rubber composition such that the center of the core has a hardness of about 72 Shore C to about 78 Shore C and a trans content of about 5% to 9%, and the outer surface of the inner core has a trans content of about 5% to 9%. The trans content of the outer surface and the center of the inner core are preferably within 2% of each other and, more preferably are substantially the same to define a zero trans gradient along a radius of the inner core.

Abstract: The present invention relates to golf balls having a low specific gravity core with specific gravities less than 1.05 and one or more high specific gravity intermediate layers with specific gravities greater than or equal to 1.05. The resulting golf balls exhibit significantly decreased spin and long distance and have the added benefit that the high specific gravity intermediate layer can be easily injection molded around the low specific gravity core.

Abstract: A golf ball 2 includes a core 4 and a cover 6 that is composed of an inner cover 8 and an outer cover 10. The core 4 has a radius of R (mm). A hardness Hs at a surface of the core 4 is greater than a hardness HL(R) when a linear approximation curve obtained by plotting a midpoint of each layer of the cover 6 in a thickness direction thereof in a graph in which a horizontal axis indicates a distance (mm) from a central point of the core 4 and a vertical axis indicates a hardness is represented by the following mathematical formula (I): HL(X)=A*X+B??(I), where X represents a distance (mm) from the central point of the core 4, HL(X) represents a hardness, and A and B represent a gradient and an intercept, respectively, of the linear approximation curve.

Abstract: The invention provides a golf ball material which is a resin mixture composed of (a) an olefin-unsaturated carboxylic acid copolymer and/or an olefin-unsaturated carboxylic acid-unsaturated carboxylic acid ester copolymer having a weight-average molecular weight (Mw) of from 40,000 to 80,000 and a weight-average molecular weight (Mw) to number-average molecular weight (Mn) ratio of from 5.0 to 8.0, or a metal neutralization product thereof, (b) an olefin-unsaturated carboxylic acid copolymer and/or an olefin-unsaturated carboxylic acid-unsaturated carboxylic acid ester copolymer having a weight-average molecular weight (Mw) of from 120,000 to 200,000 and a weight-average molecular weight (Mw) to number-average molecular weight (Mn) ratio of from 6.0 to 9.

Abstract: A multi-piece golf ball includes a core composed of a center, an envelope layer and at least one cover. The center is formed from a composition containing at least one resin component and a basic metal salt of a fatty acid. The resin component is selected from a binary copolymer composed of an olefin and an ?,?-unsaturated carboxylic acid, an ionomer resin consisting of a metal ion-neutralized product of a binary copolymer composed of an olefin and an ?,?-unsaturated carboxylic acid, a ternary copolymer composed of an olefin, an ?,?-unsaturated carboxylic acid and an ?,?-unsaturated carboxylic acid ester, and an ionomer resin consisting of a metal ion-neutralized product of a ternary copolymer composed of an olefin, an ?,?-unsaturated carboxylic acid and an ?,?-unsaturated carboxylic acid ester. The envelope layer is formed from a composition containing a thermoplastic resin and/or a thermoplastic elastomer as a resin component.

Abstract: A golf ball 2 includes a core 4, amid layer 6, a reinforcing layer 8, and a cover 10. The core 4 includes a center 12 and an envelope layer 14. The envelope layer 14 is formed by a rubber composition being crosslinked. The rubber composition includes a base rubber (a), a co-crosslinking agent (b), a crosslinking initiator (c), and an acid and/or a salt (d). The co-crosslinking agent (b) is: (b1) an ?,?-unsaturated carboxylic acid having 3 to 8 carbon atoms; or (b2) a metal salt of an ?,?-unsaturated carboxylic acid having 3 to 8 carbon atoms.

Abstract: A golf ball resin composition that is excellent in resilience includes (A) at least one resin component selected from the group consisting of (a-1) a binary copolymer composed of an olefin and an ?,?-unsaturated carboxylic acid having 3 to 8 carbon atoms, (a-2) an ionomer resin consisting of a metal ion-neutralized product of a binary copolymer composed of an olefin and an ?,?-unsaturated carboxylic acid having 3 to 8 carbon atoms, (a-3) a ternary copolymer composed of an olefin, an ?,?-unsaturated carboxylic acid having 3 to 8 carbon atoms and an ?,?-unsaturated carboxylic acid ester, and (a-4) an ionomer resin consisting of a metal ion-neutralized product of a ternary copolymer composed of an olefin, an ?,?-unsaturated carboxylic acid having 3 to 8 carbon atoms and an ?,?-unsaturated carboxylic acid ester, and (B) a basic metal salt of a fatty acid.

Abstract: A multi-piece golf ball excellent in resilience and controllability includes a core composed of a center and an envelope layer covering the center and at least one cover covering the core, wherein the center is formed from a center composition containing (A) at least one resin component selected from the group consisting of (a-1) a binary copolymer composed of an olefin and an ?,?-unsaturated carboxylic acid having 3 to 8 carbon atoms, (a-2) an ionomer resin consisting of a metal ion-neutralized product of the binary copolymer, (a-3) a ternary copolymer composed of the binary copolymer components and an ?,?-unsaturated carboxylic acid ester, and (a-4) an ionomer resin consisting of a metal ion-neutralized product of the ternary copolymer components and (B) a basic metal salt of a fatty acid, and wherein the envelope layer is formed from a rubber composition.

Abstract: Disclosed is a composition comprising, or produced from, an organic acid-modified ionomer and silica filler having oil absorption greater than 100 g oil/100 g silica. Also disclosed are articles produced from the composition such as golf balls.

Abstract: Disclosed herein is a six piece golf ball wherein each part of the golf ball has certain characteristics.

Abstract: This invention pertains to a golf ball which includes a core, optionally one or more intermediate layers; and an outer cover layer. The outer cover layer and/or one or more intermediate layers includes a blend of a) 2 to 60 wt % (based on the total weight of the blend composition) of a cyclic olefin polymer which includes a norbornene-based monomer having the general formula; where R18 to R21 independently represent a hydrogen atom, a halogen atom or a hydrocarbon group and m is from 0 to about 3; and b) about 40 to about 98 wt % (based on the total weight of the blend composition) of one or more additional polymer components. The blend composition has a melt flow index (MFI) from 1 to 80 g/10 min., a material hardness of 30 to 90 Shore D, and a flex modulus of 10 to 120 kpsi.

Abstract: This invention pertains to a golf ball which includes a core, optionally one or more intermediate layers; and an outer cover layer. The outer cover layer and/or one or more intermediate layers (if present) includes a blend of from about 2 to about 60 wt % (based on the total weight of the blend composition) of an liquid crystalline polymer (“LCP”) having the general formula; and from about 40 to about 98 wt % (based on the total weight of the blend composition) of one or more additional polymer components.

Abstract: This invention pertains to a golf ball which includes a core, optionally one or more intermediate layers; and an outer cover layer. The outer cover layer and/or one or more intermediate layers includes a blend of a) about 2 to about 40 wt % (based on the total weight of the blend composition) of an aramid polymer and b) about 60 to about 98 wt % (based on the total weight of the blend composition) of one or more additional polymer components. The blend composition has a melt flow index (MFI) from about 1 to about 80 g/10 min., a material hardness of about 30 to about 90 Shore D, and a flex modulus of about 10 to about 120 kpsi.

Abstract: A golf ball including an inner core layer formed from a thermoset rubber composition and having a first surface hardness; a thermoplastic outer core layer having a second surface hardness, an inner surface hardness, and being formed from a copolymer of ethylene and an ?,?-unsaturated carboxylic acid, an organic acid or salt thereof, and sufficient cation source to fully-neutralize the acid groups of the copolymer; an inner cover layer; and an outer cover layer; wherein the first surface hardness is substantially the same as the second surface hardness and the inner surface hardness.

Abstract: An object of the present invention is to provide a golf ball with improved durability and/or resilience by improving the adhesion between a constituent member comprising an ionomer resin and a constituent member comprising a polyurethane. The present invention provides a golf ball material composed of a multi-block copolymer having a block A that has an acid functional group neutralized with a metal ion and a block B that has lower polarity than the block A.

Abstract: An object of the present invention is to provide a golf ball excellent in fluidity, adhesion of the paint film, and repulsion. Another object of the present invention is to provide a golf ball which is excellent in durability and low-temperature durability.

Abstract: An object of the present invention is to provide a golf ball traveling 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 the spherical core is formed from a rubber composition containing (a) base rubber, (b) an ?,?-unsaturated carboxylic acid having 3 to 8 carbon atoms and/or a metal salt thereof as a co-crosslinking agent, (c) a crosslinking initiator, (d) a carboxylic acid having 1 to 14 carbon atoms and/or a salt thereof, and (e) a halogen-substituted thiophenol and/or a metal salt thereof as an organic sulfur compound, provided that the rubber composition further contains (f) a metal compound in the case of containing only (b) the ?,?-unsaturated carboxylic acid having 3 to 8 carbon atoms as the co-crosslinking agent.

Abstract: The present invention is directed to a multi-layer golf ball comprising at least one core or core layer, at least one intermediate layer, and at least one cover layer. The core has a diameter of about 1.20 to about 1.56 in. and a PGA compression of about 40 to about 90. The intermediate layer comprises a modified ionomeric polymer, and it has a thickness of about 0.01 to about 0.10 in. and a Shore D hardness of about 30 to about 70. The cover layer has a Shore D hardness of about 40 to about 75. The multi-layer golf balls of the present invention provide high driver ball speed and/or a high Coefficient of Restitution, while maintaining excellent shot feel.

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: A golf ball including a unitary core having a volume, an outer surface, a geometric center, and an outermost transition volume adjacent to the outer surface, the core being formed from a substantially homogenous composition; and a cover layer including ionomer, metallocene-catalyzed polymer, polyester, polyamide, non-ionomeric thermoplastic elastomer, copolyether-ester, copolyether-amide, polycarbonate, polybutadiene, polyisoprene, or polystyrene block copolymer. The outermost transition volume is disposed between the core outer surface and the geometric center, the transition volume has an outer portion congruent with the core outer surface, and comprises the outermost 45% of the core volume or less. Both a hardness of the core outer surface and a hardness within the outermost transition volume are less than the hardness of the geometric center to define a negative hardness gradient.

Abstract: The invention provides a golf ball having a core, at least one intermediate layer encasing the core, and a cover. The intermediate layer is formed primarily of a specific ionomer resin composition that has been highly neutralized, and the cover is formed primarily of an ionomer resin composition containing a specific amount of a granular inorganic filler. The golf ball has an excellent durability to repeated impact and a good flight performance.

Abstract: An object of the present invention is to provide a resin composition for the golf ball that suppresses the bleed out of the low molecular weight material component, as well as improves the fluidity and repulsion performance. The present invention provides a golf ball forming resin composition comprising as a resin component, (A) a high melt viscosity resin; (B) a low melt viscosity ionomer resin having a melt viscosity (190° C.) ranging from 1 Pa·s to 10 Pa·s measured by a brookfield viscometer, in a ratio of (A) the high melt viscosity resin/(B) the low melt viscosity ionomer resin being 55 mass % to 99 mass %/45 mass % to 1 mass %; and (C) a metal ion source capable of neutralizing carboxyl groups of (A) the high melt viscosity resin and (B) the low melt viscosity ionomer resin, in an amount of from 0.1 part to 10 parts with respect to 100 parts by mass of a sum of (A) the high melt viscosity resin and (B) the low melt viscosity ionomer resin.

Abstract: An object of the invention is to provide a golf ball excellent in the durability at the normal and low temperatures, flight distance, and shot feeling on the shots. Another object of the present invention is to provide a golf ball excellent in a direction stability on the shots. The present invention provides a golf ball comprising: a core consisting of at least one layer; and a cover covering the core and having a thickness ranging from 0.3 mm to 1.0 mm, wherein the cover is formed from a cover composition that contains as a resin component, (A) a highly elastic polyamide resin (B) a metal-neutralized product of binary copolymer and/or ternary copolymer, and (C) a resin having a polar functional group in a specific amount, and wherein the cover composition has a slab hardness ranging from 65 to 75 in Shore D hardness.

Abstract: An object of the present invention is to provide a golf ball providing a great distance. The present invention provides a golf ball comprising: a core consisting of a center and one or more intermediate layers covering the center; and a cover covering the core, wherein at least one of said intermediate layers is formed from a high fluidity intermediate layer composition that contains (A) a polyamide resin composition having a flexural modulus in a range from 500 MPa to 4,000 MPa and a melt flow rate (240° C., 2.16 kg) of 5.0 g/10 min or more, and (B) at least one member selected from the group consisting of an ethylene-(meth)acrylic acid binary copolymer, a metal-neutralized product of the binary copolymer, an ethylene-(meth)acrylic acid-(meth)acrylic acid ester ternary copolymer, and a metal-neutralized product of the ternary copolymer.

Abstract: The present invention relates to golf balls and golf ball components comprising a blend of one or more ionomers mixed with one or more metal or ammonium salts of chelating agent. The resulting modified ionomer compositions have improved processability as shown by the increase in melt flow index (I2) as compared to the unmodified ionomer analogs while demonstrating an increase in resiliency or speed as shown by increasing COR, while maintaining or showing only a slight increase in hardness as measured by Shore D.

Abstract: A golf ball 2 includes a spherical core 4, an inner mid layer 6 positioned outside the core 4, an outer mid layer 8 positioned outside the inner mid layer 6, a reinforcing layer 10 positioned outside the outer mid layer 8, and a cover 12 positioned outside the reinforcing layer 10. When distances (%) from a central point of the core 4 to nine points and JIS-C hardnesses at the nine points, which nine points are obtained by dividing a region from the central point of the core 4 to a surface of the core 4 at intervals of 12.5% of a radius of the core 4, are plotted in a graph, R2 of a linear approximation curve obtained by a least-square method is equal to or greater than 0.95.

Abstract: The invention provides a multi-piece solid golf ball having a solid core, at least one intermediate layer and a cover. The core has a hardness which gradually increases from a core center to a core surface, with the golf ball having specific values for the hardness difference between the core center and the core surface; the hardness difference (I)-(II) in JIS-C hardness units being not more than ±2; the (hardness of intermediate layer material)?(hardness of core surface); the (initial velocity of sphere composed of core encased by intermediate layer)?(initial velocity of core); the (deflection of sphere composed of core encased by intermediate layer)/(deflection of core); and the (hardness of cover material)?(hardness of intermediate layer material).

Abstract: The invention provides a golf ball in which an intermediate layer formed of a highly neutralized resin mixture obtained by using two nonionic resins of differing weight-average molecular weights and breadths of molecular weight distribution (weight-average molecular weight/number-average molecular weight) as the base resin and adding thereto an organic acid or a metal salt thereof and a basic inorganic metal compound capable of being neutralized is combined with a cover formed of an ionic resin having a weight-average molecular weight in a specific range and a breadth of molecular weight distribution (weight-average molecular weight/number-average molecular weight) in a specific range. The golf ball material of the invention has an excellent rebound and durability.

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: An objective of the present invention is to provide a golf ball striking a balance between the flight distance on the driver shots and the approach performance on the approach shots and having the excellent shot feeling and durability.