In a golf ball having a rubber core of at least one layer and a cover of at least one layer encasing the core, at least one layer of the cover is formed of a resin composition that includes (A) polyurethane or polyurea, and (B) a thermoplastic polyester elastomer. Component (B) is included in a ratio of not more than 45 wt % of the overall amount of the resin composition, and the resin composition has a Shore D hardness of 42 or less and a rebound resilience of from 60 to 72%. The golf ball has an excellent controllability on approach shots, is able to maintain a good feel at impact and a good scuff resistance, and also has a good moldability.

Methods for making multi-piece golf balls comprising at least one component made of ethylene-propylene diene copolymer (EPDM) rubber and the resulting balls are provided. The multi-piece golf ball includes a cover, preferably a dual-cover having inner and outer cover layers. The outer cover is preferably made of a liquid rubber composition based on liquid EPDM rubber. In one version, the ball sub-assembly is dipped in a bath containing liquid EPDM rubber to form the outer cover. In another version, a casting method is used and the liquid EPDM rubber is dispensed into mold cavities to form the outer cover. The inner core of the ball may be made of polybutadiene rubber and the outer core layer may be made of EPDM rubber. The resulting golf ball has high resiliency, a soft feel, and good weatherability.

A method and an apparatus for playing golf on a hard surface comprises a replaceable striking pad attached to a conventional golf club head by means of at least one attachment means, a spiked ball, a portable ball trap to trap the spiked ball and an optional remotely controlled vehicle to position the portable ball trap. The replaceable striking pad includes a small lip at a bottom end on a front face and a holding ledge having substantially curved edges extending away from the bottom end of the front face. The holding ledge is adaptable to wrap around a bottom sole of the golf club head. The portable ball trap includes a thin flat platform with tapered edges, a central threaded pole positioned on the thin flat platform and a circular frame having a plurality of hinged tabs threaded to the central threaded pole.

A rubber composition for a golf ball core includes (a) a conjugated diene polymer, (b) a copolymer of a conjugated diene compound and a non-conjugated olefin, and (c) an organic peroxide. Golf balls having at least one core layer formed of such a rubber composition and a cover of one or more layers encasing the core exhibit improved durability to cracking on repeated impact while maintaining the basic properties required of golf balls, such as flight and spin controllability on approach shots.

The present invention provides methods for producing golf balls having polyurethane covers and the resultant balls. Multi-piece golf balls having an inner core and outer cover with one or more intermediate layers disposed between the core and cover can be formed. The methods involve producing hydroxyl-terminated adducts and isocyanate-terminated prepolymers. Thermoset and thermoplastic polyurethane compositions can be prepared. The resulting polyurethane compositions and golf ball covers have high thermal stability and good wear-resistance and durability.

A golf ball includes a core, a mid layer, and a cover. An amount of compressive deformation C3 of the golf ball can be not less than 2.80 mm. The golf ball can satisfy the following mathematical formulas (1) and (2):

C1>(124.8−Hs)/11.5   (1)

C2−C1≥(−1/6*C1+(68−H2)/20+(5−Hd)/ 100)*T2   (2), where

C1 is an amount of compressive deformation (mm) of the core,

C2 is an amount of compressive deformation (mm) of a sphere including the core and the mid layer,

Hd is Hs−Ho,

Ho is a hardness (Shore C) of a center the core,

Hs is a hardness (Shore C) of a surface of the core,

H2 is a hardness (Shore D) of the mid layer, and

T2 is a thickness (mm) of the mid layer.

A golf ball can include a core, a mid layer, and a cover. The golf ball can satisfy the following mathematical formulas (1), (2), and (3):

C1≤(124.8−Hs)/11.5  (1)

C2−C1≥(−⅙*C1+(68−H2)/20+(5−Hd)/100)*T2  (2)

10≤H2*T2−H3*T3  (3), where

C1 is an amount of compressive deformation (mm) of the core,

C2 is an amount of compressive deformation (mm) of a sphere including the core and the mid layer,

Hd is Hs−Ho,

Ho is a hardness (Shore C) of a center the core,

Hs is a hardness (Shore C) of a surface of the core,

H2 is a hardness (Shore D) of the mid layer,

H3 is a hardness (Shore D) of the cover,

T2 is a thickness (mm) of the mid layer, and

T3 is a thickness (mm) of the cover.

A golf ball of the present invention includes a core and a cover located outside the core and having a plurality of dimples on a surface thereof A bottom of each of the dimples has a curved shape protruding toward an outside of the golf ball. A depth d of a center protruding portion of the bottom of the dimple is a perpendicular distance between a line S connecting both ends of an outer periphery of the dimple and a highest point of the protruding portion. A volume occupation ratio VR of the dimple is less than 0.75. A relationship between Shore D hardness H of a material of the cover and the depth d (unit: mm) satisfies the following Formula 1:

(H-83)/(−300)>d   (Formula 1).

A golf ball 2 includes a main body 4 and a paint layer 6 positioned outside the main body 4. The main body 4 includes a spherical core 8, a mid layer 10 positioned outside the core 8, and a cover 12 positioned outside the mid layer 10. An indentation depth, measured when the paint layer 6 in a cross-section along a plane passing through a central point of the golf ball 2 is pressed by a force of 30 mgf in a direction perpendicular to the cross-section, is not less than 300 nm and not greater than 3000 nm. The paint layer 6 preferably has a thickness of not less than 5 μm and not greater than 50 μm.

An object of the present invention is to provide a golf ball having excellent durability. The present invention provides a golf ball comprising a core and at least one cover layer covering the core, wherein the core is formed from a core rubber composition containing (a) a base rubber, (b) an α,β-unsaturated carboxylic acid having 3 to 8 carbon atoms and/or a metal salt thereof as a co-crosslinking agent, (c) a crosslinking initiator, and (d) a hindered phenol compound, and (b) the co-crosslinking agent and (d) the hindered phenol compound are blended in the core rubber composition such that the following expression (1) is satisfied:
0.04≤HF/B≤0.35  (1) in the formula (1), HF=a number of OH functional group in one molecule of (d) the hindered phenol compound×an amount of (d) the hindered phenol compound (mole) with respect to 100 parts by mass of (a) the base rubber, and B=an amount of (b) the co-crosslinking agent (mole) with respect to 100 parts by mass of (a) the base rubber.