Solid golf ball

Details Solid golf ball Solid golf ball

2002-11-21

2004-05-04

Gorden, Raeann (Department: 3711)

Games using tangible projectile

Golf

Ball

C525S193000

Reexamination Certificate

active

06729973

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates to a solid golf ball. More particularly, it relates to a solid golf ball having excellent rebound characteristics and excellent durability, and showing good workability when producing.
BACKGROUND OF THE INVENTION
Hitherto, a rubber composition comprising a polybutadiene containing a cis-1,4 bond of not less than 80%, synthesized using nickel-containing catalyst, has been suitably used as a rubber composition for a one-piece solid golf ball, a core of a two-piece golf ball or three-piece golf ball, or a solid center of a thread wound golf ball, in view of rebound characteristics and durability. It is also known that a polybutadiene, synthesized using lanthanide-containing catalyst, can be used for the same application.
It is disclosed, for example, in Japanese Patent Kokoku Publication No. 80123/1994 that a mixture consisting of
(i) a polybutadiene containing a cis-1,4 bond of not less than 40%, having a Mooney viscosity of 70 to 100 ML
1+4
(100° C.), synthesized using nickel-containing catalyst and/or cobalt-containing catalyst, and
(ii) a polybutadiene containing a cis-1,4 bond of not less than 40%, having a Mooney viscosity of 30 to 90 ML
1+4
(100° C.), synthesized using a catalyst consisting of lanthanide rare earth elements-containing compound, or a polybutadiene containing a cis-1,4 bond of not less than 40%, having a Mooney viscosity of 20 to 50 ML
1+4
(100° C.), synthesized using nickel-containing catalyst and/or cobalt-containing catalyst
can be suitably used as a rubber composition for golf balls. When the polybutadiene (i) is used for the rubber composition, rebound characteristics of the resulting golf ball are improved. However, when the polybutadiene (ii) having high Mooney viscosity is used in combination with the polybutadiene (i), workability when producing is degraded.
It is disclosed in Japanese Patent No. 2644226 that a polybutadiene containing a cis-1,4 bond of not less than 80% and having a Mooney viscosity of 45 to 90 ML
1+4
(100° C.) and a ratio (Mw/Mn) of weight average molecular weight (Mw) to number average molecular weight (Mn) of 4.0 to 8.0 can be suitably used for golf balls. Although the use of the polybutadiene imparts sufficient physical properties to golf balls, improvement on rebound characteristics and durability is further required.
It is disclosed in Japanese Patent No. 2678240 that a mixture of
85 to 15 phr of a nickel- or cobalt-catalyzed polybutadiene having a cis-1,4 content of more than 40% and a Mooney viscosity of less than 50, and
15 to 85 phr of a lanthanide-catalyzed polybutadiene having a cis-1,4 content of more than 40% and a Mooney viscosity of less than 50
can be suitably used for a golf ball. However, when the mixture of the nickel- or cobalt-catalyzed polybutadiene having low Mooney viscosity (less than 50) and the lanthanide-catalyzed polybutadiene having low Mooney viscosity (less than 50), rebound characteristics and durability of the resulting golf ball are not sufficiently obtained.
In Japanese Patent Kokai Publication No. 319148/1999, a solid golf ball comprising a core and a cover covering the core, of which the core comprises at least one rubber layer formed from a rubber composition comprising a polybutadiene mixture, unsaturated carboxylic acid or a metal salt of unsaturated carboxylic acid, organic peroxide and inorganic filler, is disclosed. The polybutadiene mixture consists of
(a) a polybutadiene containing a cis-1,4 bond of not less than 80 molar %, having a Mooney viscosity of 50 to 69 ML
1+4
(100° C.) and a ratio (Mw/Mn) of weight average molecular weight (Mw) to number average molecular weight (Mn) of 4.0 to 8.0, synthesized using nickel-containing catalyst and/or cobalt-containing catalyst, and
(b) a polybutadiene containing a cis-1,4 bond of not less than 40%, having a Mooney viscosity of 20 to 90 ML
1+4
(100° C.), synthesized using lanthanide-containing catalyst,
and a weight ratio (a)/(b) is 30/70 to 90/10. However, workability when producing is degraded and rebound characteristics of the resulting golf ball are not sufficiently obtained.
In Japanese Patent Kokai Publication Nos. 149502/2001, 149503/2001, 149505/2001, 149506/2001, 149507/2001 and 149508/2001, a golf ball comprising a vulcanized molded article of rubber composition comprising polybutadiene. The polybutadiene, of which a 5 mass % toluene solution viscosity at 25° C., a ratio (Mw/Mn) of weight average molecular weight (Mw) to number average molecular weight (Mn) and a Mooney viscosity are adjusted to specified ranges, is synthesized using rare earth element-containing catalyst. However, workability when producing is degraded and rebound characteristics of the resulting golf ball are not sufficiently obtained.
OBJECTS OF THE INVENTION
A main object of the present invention is to provide a solid golf ball having excellent rebound characteristics and excellent durability, and showing good workability when producing.
According to the present invention, the object described above has been accomplished by providing a solid golf ball composed of at least one layer of a rubber material formed from rubber composition comprising a polybutadiene synthesized using lanthanide-containing catalyst, and adjusting the Mooney viscosity, weight average molecular weight (Mw) and molecular weight distribution (Mw/Mn) of the polybutadiene to a specified range, thereby providing a solid golf ball having excellent rebound characteristics and excellent durability, and showing good workability when producing.
SUMMARY OF THE INVENTION
The present invention provides a solid golf ball composed of at least one layer of a rubber material as a component, wherein
the rubber material is formed from the rubber composition comprising a base rubber, a co-crosslinking agent, an organic peroxide and an inorganic filler, and
the rubber composition comprises 10 to 100 parts by weight of a polybutadiene containing a cis-1,4 bond of not less than 80%, having a Mooney viscosity of not less than 50 to less than 65 ML
1+4
(100° C.), a ratio (Mw/Mn) of weight average molecular weight (Mw) to number average molecular weight (Mn) of 2.5 to 3.5 and Mw of 50×10
4
to 70×10
4
, synthesized using lanthanide-containing catalyst, based on 100 parts by weight of the base rubber.
In order to put the present invention into a more suitable practical application, it is preferable that:
the polybutadiene has a content of a 1,2-bond of not more than 1.8%;
the polybutadiene have a 5 mass % toluene solution viscosity at 25° C. (V
S
) of 400 to 550 mPa-s; and
the 5 mass % toluene solution viscosity at 25° C. (V
S
), the Mooney viscosity (V
M
) and the weight average molecular weight (Mw) of the polybutadiene satisfy a correlation represented by the following formula:
265
≦V
S
−(
V
M
+Mw/
10
4
)≦450
DETAILED DESCRIPTION OF THE INVENTION
The rubber composition comprising the specified polybutadiene of the present invention is vulcanized by press-molding under applied heat to obtain a one-piece solid golf ball. The rubber composition of the present invention may be used for forming at least one portion or all of the core of a two-piece solid golf ball or a multi-piece solid golf ball, such as a three-piece solid golf ball, which consists of a core of rubber material and a cover of thermoplastic resin covering on the core. In order to explain the rubber composition for golf ball of the present invention simply, a core of two-piece golf ball will be mainly used hereinafter for explanation. However, the rubber composition may be applied to the one-piece golf ball and the core of the multi-piece solid golf ball other than the two-piece solid golf ball.
The solid golf ball of the present invention is formed by vulcanizing and press-molding the rubber composition described above to obtain a core, followed by covering the core with the cover. The core used for the solid golf ball of the present invention is obtained by vulcanizing and press-molding the rubber composition. The rubber compos

Affiliated with

Also associated with

Rating

Solid golf ball does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Solid golf ball, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Solid golf ball will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-3252926