In a multi-piece solid golf ball having a core, an envelope layer, an intermediate layer and a cover, the core is formed of one or more layer of a rubber composition; the envelope layer, intermediate layer and cover are each formed of a single layer of resin material; the hardness relationship among the layers satisfies the following two conditions:

material hardness of cover>material hardness of intermediate layer, and

material hardness of envelope layer≥surface hardness of core;

the ball additionally satisfies the condition: envelope layer thickness (mm)×envelope layer material hardness (Shore D hardness) cover thickness (mm)×cover material hardness (Shore D hardness); and the core and ball have optimized deflections when subjected to a specific loading. This ball serves as a distance ball which enables a superior distance to be achieved on full shots with a driver and with irons.

Golf ball incorporating polyurethane mixture having wt. % NCO content of 4-20 and including a prepolymer polyol portion comprised of trans--Farnesene diol(s) in an amount of about 3-70 wt. % of total weight of prepolymer. Trans--Farnesene diol may be 15 carbon, long chain, branched, unsaturated 3,4-vinyl-containing bio-hydrocarbon having the formula: ##STR00001## Prepolymer can include a 1:99 to 99:1 blend (wt. % ratio) of Trans--Farnesene diol(s) and polybutadiene-based polyol(s) in an amount of about 35-85 wt. %, along with about 15 wt. %-65 wt. % of diisocyanate(s). Curative may be combined with prepolymer in amount of about 3-25 wt. % of total weight of curative and prepolymer combined, and may be mixture of aromatic diamine(s) and white dispersion in a wt. % ratio of about 90:10 to 50:50, plus catalyst. Hardness of polyurethane mixture can be from 75. Shore A to 75 Shore D or a material hardness can be from about 40 Shore D to about 65 Shore D.

Golf ball incorporating polyurethane mixture having wt. % NCO content of 4-20 and including a prepolymer polyol portion comprised of trans--Farnesene diol(s) in an amount of about 3-70 wt. % of total weight of prepolymer. Trans--Farnesene diol may be 15 carbon, long chain, branched, unsaturated 3,4-vinyl-containing bio-hydrocarbon having the formula:

##STR00001##

Prepolymer can include a 1:99 to 99:1 blend (wt. % ratio) of Trans--Farnesene diol(s) and polybutadiene-based polyol(s) in an amount of about 35-85 wt. %, along with about 15 wt. %-65 wt. % of diisocyanate(s). Curative may be combined with prepolymer in amount of about 3-25 wt. % of total weight of curative and prepolymer combined, and may be mixture of aromatic diamine(s) and white dispersion in a wt. % ratio of about 90:10 to 50:50, plus catalyst. Hardness of polyurethane mixture can be from 75 Shore A to 75 Shore D or a material hardness can be from about 40 Shore D to about 65 Shore D.

The golf ball includes a core, an intermediate layer, and a cover, in which the core is formed of a rubber composition into a single layer or a plurality of layers, the intermediate layer and the cover are both formed of a single-layer resin composition, and a relationship between an initial velocity of the core, an initial velocity of a sphere (intermediate layer-encased sphere) in which the core is encased with the intermediate layer, and an initial velocity of a sphere (ball) in which the intermediate layer-encased sphere is encased with the cover satisfies the following two conditions:

(initial velocity of ball)<(initial velocity of intermediate layer-encased sphere)

0.60?(initial velocity of intermediate layer-encased sphere)?(initial velocity of core)?1.00 (m/s). and the specific deflection is 3.00 mm or less, and a specific gravity of the intermediate layer is 1.05 or more.

A golf ball comprising an inner core comprising polybutadiene, and an outer core comprising a polybutadiene material, a graphene material and a carbon nanotube material (CNT) is disclosed herein. Improved durability of the core by using a mixture of graphene and CNT can result in higher mean time to fail (MTTF) upon repeated impact in a high speed testing device, or with a golf club in normal play.

In a golf ball having a core and a cover of one or more layers, letting the core diameter be D (mm), the cover thickness be T (mm) and the core and ball deflections when compressed under a final load of 1,275 N (130 kgf) from an initial load state of 98 N (10 kgf) be 5 (mm) and B (mm), the following conditions are satisfied: (1) 30D/T24, (2) 3.9E/T3.0, and (3) 1.18E/B1.09. This golf ball provides an excellent flight performance and a soft feel at impact when used by golfers whose head speed is not very fast, such as senior golfers and women golfers. The ball also has a high durability to cracking on repeated impact.

In a multi-piece solid golf ball having a core, an envelope layer, an intermediate layer and a cover, the core is formed of one or more layer of a rubber composition; the envelope layer, intermediate layer and cover are each formed of a single layer of resin material; the hardness relationship among the layers satisfies the following two conditions:
material hardness of cover>material hardness of intermediate layer, and
material hardness of envelope layersurface hardness of core;
the ball additionally satisfies the condition: envelope layer thickness (mm)envelope layer material hardness (Shore D hardness) cover thickness (mm)cover material hardness (Shore D hardness); and the core and ball have optimized deflections when subjected to a specific loading. This ball serves as a distance ball which enables a superior distance to be achieved on full shots with a driver and with irons.

The present invention relates to a golf ball and a method for manufacturing same. The golf ball may include a first pole, a second pole, and a seam located between the first pole and the second pole, and a section structure including an outer surface having a plurality of dimples, a core, and a cover surrounding the core. In certain embodiments, the core includes 100 parts by weight of a butadiene rubber and 0.5 to 10 parts by weight of a polymer resin. The cover may include 100 parts by weight of an ionomer resin and 1 to 10 parts by weight of a butadiene rubber having a 1,2-bond content of 90% or more.

A golf ball includes at least one intermediate layer formed between a core and a cover, wherein a standard deviation of a specific gravity of each layer of the core, the intermediate layer, the cover is within 0.07, and the cover is formed of a resin composition that includes the following components (I) and (II): (I) polyurethane (II) (meth)acrylic block copolymer,
and the cover satisfies the following condition (1):

[00001]$\begin{array}{cc}0.1{\mathrm{VR}}_{L}V{R}_{H}0.26& \left(1\right)\end{array}$

[in the above condition, VR.sub.L represents a viscosity at 210 C. and a viscosity at 200 C. at a predetermined shear rate, and VR.sub.H represents a ratio between a viscosity 3 at 230 C. and a viscosity at 220 C. at the predetermined shear rate].