Multi-piece solid golf ball

• US 20060128504A1
• Filed: 02/08/2006
• Published: 06/15/2006
• Est. Priority Date: 01/28/2004
• Status: Active Grant

• Current Assignee: Bridgestone Sports Co Limited (Bridgestone Corporation)
• Original Assignee: Bridgestone Sports Co Limited (Bridgestone Corporation)
• Inventors: Watanabe, Hideo, Hayashi, Junji, Takesue, Rinya
• Granted Patent: US 7,270,614 B2
• Time in Patent Office: Days
• US Class Current: 473/371
• CPC Class Codes: A63B 37/0003 Golf balls
• CPC Class Codes: A63B 37/0031 Hardness
• CPC Class Codes: A63B 37/0033 Thickness
• CPC Class Codes: A63B 37/0036 Melt flow rate [MFR]
• CPC Class Codes: A63B 37/0039 characterised by the material
• CPC Class Codes: A63B 37/0043 Hardness
• CPC Class Codes: A63B 37/0045 Thickness
• CPC Class Codes: A63B 37/0046 Deflection or compression
• CPC Class Codes: A63B 37/0062 Hardness
• CPC Class Codes: A63B 37/0064 Diameter
• CPC Class Codes: A63B 37/0068 Initial velocity

Abstract

In the present invention, by optimizing the balance of Shore D hardness between the intermediate layer and the cover, the balance of Shore D hardness between the surface and the center in the core, the balance of initial velocity between the core and the sphere, and the balance of Deflection amount between the core and the sphere are optimized, and the total thickness of the intermediate layer and the cover, the inventive golf ball is given a good profile of rebound, feel, controllability and durability.

Claims

1. A multi-piece solid golf ball comprising a core, an intermediate layer enclosing the core to form a sphere, and a cover enclosing the intermediate layer, and numerous dimples formed on a surface of the cover, wherein the each component has a Shore D hardness, a Deflection amount, an initial velocity (in m/s) and a thickness (in mm), the Deflection amount being defined as an amount of deflection (in mm) under load of a spherical body incurred when the load is increased from an initial value of 98 N (10 kgf) to a final value of 1275 N (130 kgf), and the ball satisfies the following requirements (1) to (4), (11) &

(12);

(1) (Shore D hardness of the cover)−

(Shore D hardness of the intermediate layer)>

0,

(2A) (initial velocity of the core)−

(initial velocity of the ball)≧

0,

(3) 0.87≦

(Deflection amount of the sphere)/(Deflection amount of the core)≦

0.97,

(4) the total of the thickness of the intermediate layer and the thickness of the cover is up to 3.0 mm,

(11) (Deflection amount of the golf ball)/(Deflection amount of the sphere)≦

0.98, and

(12) (Shore D hardness of core surface)−

(Shore D hardness of core center)≧

15.

2. The multi-piece solid golf ball of claim 1 wherein sulfur is compounded in an amount of 0.05 to 0.5 part by weight, and an organosulfur compound is compounded in an amount of 0.05 to 5 parts by weight, per 100 parts by weight of the base rubber, and the satisfies the following requirement.

1≦

(amount of the organosulfur compound)/(amount of the sulfur)≦

30.

3. The multi-piece solid golf ball of claim 1 wherein the total number of the dimples is at least 280 and not more than 360 and the ball has a coefficient of lift (CL) when hit of at least 0.165 at a Reynolds number of 70,000 and a spin rate of 2,000 rpm, and a coefficient of drag (CD) when hit of not more than 0.230 at a Reynolds number of 180,000 and a spin rate of 2,520 rpm.

4. The multi-piece solid golf ball of claim 1 which further satisfies the following requirements (5) to (9):

(5) the thickness of the cover is from 0.5 mm to 2.0 mm,

(6) the Shore D hardness of the cover is from 52 to 62,

(7) the thickness of the intermediate layer is from 0.5 mm to 1.6 mm,

(8) the Shore D hardness of the intermediate layer is from 40 to 60, and

(9) the golf ball has an initial velocity of at least 76.5 m/s.

5. The multi-piece solid golf ball of claim 1 which further satisfies the following requirements (10):

(10) the cover has a melt flow rate (MFR) of at least 2 g/10 min.

6. The multi-piece solid golf ball of claim 1 wherein the value as described in the requirement (11) is at least 0.85 and not more than 0.95.

7. The golf ball of claim 1 wherein said intermediate layer comprises

(A) an ionomer resin comprising

(a-1) an olefin/unsaturated carboxylic acid binary random copolymer and/or a metal ion neutralized product thereof and

(a-2) an olefin/unsaturated carboxylic acid/unsaturated carboxylic acid ester ternary random copolymer and/or a metal ion neutralized product thereof in a weight ratio (a-1)/(a-2) between 100/0 and 0/100, and

(B) a non-ionomeric thermoplastic elastomer in a weight ratio A/B between 100/0 and 50/50.

8. The golf ball of claim 7 wherein said intermediate layer is made of a mixture comprising parts by weight of a resin component comprising the ionomer resin (A) and the non-ionomeric thermoplastic elastomer (B) in a weight ratio A/B between 100/0 and 50/50,

(C) 5 to 80 parts by weight of an organic fatty acid and/or a derivative thereof having a molecular weight of 280 to 1,500, and

(D) 0.1 to 10 parts by weight of a basic inorganic metal compound capable of neutralizing un-neutralized acid groups in said resin component and component (C).