U.S. patent number RE40,118 [Application Number 10/788,045] was granted by the patent office on 2008-02-26 for multi-piece solid golf ball.
This patent grant is currently assigned to Bridgestone Corporation. Invention is credited to Akira Kimura, Yasumasa Shimizu, Hideo Watanabe.
United States Patent |
RE40,118 |
Watanabe , et al. |
February 26, 2008 |
Multi-piece solid golf ball
Abstract
A multi-piece solid golf ball includes a solid core, at least
one intermediate layer, and a cover having at least one cover
layer. The solid core has a compression deflection of 3.0 mm or
more, the intermediate layer is mainly made from a thermoplastic
resin and has a Shore D hardness of 45 to 55 and a specific gravity
of 1.2 or less, and the cover has a Shore D hardness of 60 or more
and a thickness of 1.6 to 2.3 mm. The golf ball further comprises a
ratio of the compression deflection of a sphere composed of the
solid core covered with the intermediate layer to the compression
deflection of the solid core is more than 0.900 and less than
0.970; and a difference in JIS-C hardness between the surface and
the center of the solid core is equal to or less than 5.
Inventors: |
Watanabe; Hideo (Chichibu,
JP), Shimizu; Yasumasa (Chichibu, JP),
Kimura; Akira (Chichibu, JP) |
Assignee: |
Bridgestone Corporation (Tokyo,
JP)
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Family
ID: |
18555233 |
Appl.
No.: |
10/788,045 |
Filed: |
February 27, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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Reissue of: |
09776663 |
Feb 6, 2001 |
06561925 |
May 13, 2003 |
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Foreign Application Priority Data
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Feb 8, 2000 [JP] |
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2000-030190 |
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Current U.S.
Class: |
473/371; 473/367;
473/368; 473/370; 473/372; 473/373; 473/374; 473/376; 473/377 |
Current CPC
Class: |
A63B
37/0003 (20130101); A63B 37/04 (20130101); A63B
37/0031 (20130101); A63B 37/0033 (20130101); A63B
37/0043 (20130101); A63B 37/0047 (20130101); A63B
37/0062 (20130101); A63B 37/0064 (20130101); A63B
37/0065 (20130101); A63B 37/0066 (20130101); A63B
37/0075 (20130101); A63B 2209/00 (20130101) |
Current International
Class: |
A63B
37/04 (20060101); A63B 37/06 (20060101) |
Field of
Search: |
;473/351-377 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Other References
MR. Farrally et al., Science and Golf III: Proceedings of the World
Scientific Congress of Golf, Illinois: Human Kinetics, copy right
1999, p. 411. cited by examiner.
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Primary Examiner: Kim; Eugene
Assistant Examiner: Hunter; Alvin A
Attorney, Agent or Firm: Sughrue Mion, PLLC
Claims
What is claimed is:
1. A multi-piece solid golf ball comprising: a solid core; at least
one intermediate layer for covering said solid core; and a cover
having at least one cover layer for covering said intermediate
layer; wherein said solid core has a comparison deflection of 3.0
mm or more when a load range of initial 10 kgf to final 130 kgf is
applied, said intermediate layer is mainly made from a
thermoplastic resin and has a Shore D hardness of 45 to 55 and a
specific gravity of 1.2 or less .Iadd.and less than a specific
gravity of said solid core.Iaddend., and said cover has a Shore D
hardness of 60 or more and a thickness of 1.6 to 2.3 mm; a ratio of
the compression deflection of a sphere composed of said
intermediate layer and said solid core covered therewith to the
compression deflection of said solid core is more than 0.900 and
less than 0.970 .Iadd.[0.900<(compression deflection of
sphere/compression deflection of solid core)<0.970].Iaddend.;
and a difference in JIS-C hardness (specified under JIS K6301-1996)
between the surface and the center of said solid core is equal to
or .[.less.]. .Iadd.greater .Iaddend.than 5
.Iadd.[5.ltoreq.(surface hardness-center hardness)].Iaddend..
2. A multi-piece solid golf ball according to claim 1, wherein the
gage of said intermediate layer is equal to or less than 2.0
mm.
.Iadd.3. A multi-piece solid golf ball according to claim 1,
wherein said difference in JIS-C hardness between the surface and
the center of said solid core is equal to or less than
22..Iaddend.
.Iadd.4. A multi-piece solid golf ball according to claim 1,
wherein said ratio of the compression deflection of said sphere
composed of said intermediate layer and said solid core covered
therewith to the compression deflection of the solid core is more
than 0.910 and less than 0.960..Iaddend.
.Iadd.5. A multi-piece solid golf ball comprising: a solid core; at
least one intermediate layer for covering said solid core; and a
cover having at least one cover layer for covering said
intermediate layer; wherein said solid core has a compression
deflection of 3.0 mm or more when a load range of initial 10 kgf to
final 130 kgf is applied, said intermediate layer is mainly made
from a thermoplastic resin and has a Shore D hardness of 45 to 55
and a specific gravity of 1.2 or less and less than a specific
gravity of said solid core, and said cover has a Shore D hardness
of 60 or more; a ratio of the compression deflection of a sphere
composed of said intermediate layer and said solid core covered
therewith to the compression deflection of said solid core is more
than 0.900 and less than 0.970; and a difference in JIS-C hardness
(specified under JIS K6301-1996) between the surface and the center
of said solid core is equal to or greater than 5 [5.ltoreq.(surface
hardness-center hardness)]..Iaddend.
Description
BACKGROUND OF THE INVENTION
The present invention relates to a multi-piece solid golf ball
having at least three layers, more specifically, a solid core, at
least intermediate layer, and a cover having at least one cover
layer, and particularly to a multi-piece solid golf ball which is
capable of giving a player a desirable soft feeling of hitting the
golf ball upon putter shot or approach shot and also a desirable
feeling of hitting the golf ball upon driver shot, and which is
capable of improving the flying performance of the golf ball.
Solid golf balls have been variously improved. For example, an
attempt has been made to soften the hardness of a cover of a
two-piece golf ball for giving a player a desirable feeling of
hitting the golf ball.
In the case of the above two-piece golf ball, however, if the
hardness of the cover is softened, there arises a new problem that
the flying distance of the golf ball is shortened.
On the other hand, it has been known that the flying performance of
a golf ball can be improved by increasing the hardness of a cover
of the golf ball; however, in this case, there arises another
problem that the player's feeling of hitting the golf ball upon
putter shot or approach shot is degraded.
In this way, it has been difficult to obtain a solid golf ball
capable of giving a player a desirable feeling of hitting the golf
ball as well as improving the flying performance of the golf
ball.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a multi-piece
solid golf ball which is capable of giving a player a desirable
feeling of hitting the golf ball upon putter shot or approach shot
and also a desirable feeling of hitting the golf ball upon driver
shot, and which is capable of improving the flying performance of
the golf ball.
To achieve the above object, the present inventor has made studies
on a multi-piece solid golf ball including at least one
intermediate layer between a solid core and a cover.
Eventually, the present inventor has found that a multi-piece solid
golf ball characterized in that the solid core has a compression
deflection of 3.0 mm or more when a load range of initial 10 kgf to
final 130 kgf is applied, the intermediate layer is mainly made
from a thermoplastic resin and has a Shore D hardness (ASTM
D-2240-75) of 45 to 55 and a specific gravity of 1.2 or less, and
the cover has a Shore D hardness of 60 or more and a thickness of
1.6 to 2.3 mm; a ratio of the compression deflection of a sphere
composed of the intermediate layer and the solid core covered
therewith to the compression deflection of the solid core is more
than 0.900 and less than 0.970 [0.900<(compression deflection of
sphere/compression deflection of solid core)<0.970]; and a
difference in JIS-C hardness (specified under JIS K6301-1996)
between the surface and the center of the solid core is equal to or
.[.less.]. .Iadd.greater .Iaddend.than 5 [5.ltoreq.(surface
hardness-center hardness)], is advantageous in that the hardness
distribution of the solid core, the intermediate layer, and the
cover are optimized by specifying the difference in hardness
between the surface and the center of the solid core and by
increasing the repulsion characteristic of the intermediate layer
and increasing the hardness of the cover, with a result that such a
golf ball is capable of giving a player a desirable soft feeling of
hitting the golf ball upon putter shot or approach shot and also a
desirable feeling of hitting the golf ball upon driver shot, and is
capable of improving the flying performance of the golf ball to
such an extent as to satisfy a player of an average class with a
head speed of 40 m/s or less.
Accordingly, the present invention provides a multi-piece solid
golf ball comprising: a solid core; at least one intermediate layer
for covering the solid core; and a cover having at least one cover
layer for covering the intermediate layer; wherein the solid core
has a compression deflection of 3.0 mm or more when a load range of
initial 10 kgf to final 130 kgf is applied, the intermediate layer
is mainly made from a thermoplastic resin and has a Shore D
hardness of 45 to 55 and a specific gravity of 1.2 or less, and the
cover has a Shore D hardness of 60 or more and a thickness of 1.6
to 2.3 mm; a ratio of the compression deflection of a sphere
composed of the intermediate layer and the solid core covered
therewith to the compression deflection of the solid core is more
than 0.900 and less than 0.970 [0.900<(compression deflection of
sphere/compression deflection of solid core)<0.970]; and a
difference in JIS-C hardness (specified under JIS K6301-1996)
between the surface and the center of the solid core is equal to or
.[.less.]. .Iadd.greater .Iaddend.than 5 [5.ltoreq.(surface
hardness-center hardness)].
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a sectional view showing one embodiment of a multi-piece
solid golf ball of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The present invention will be described in detail with reference to
the accompanying drawing.
Referring to FIG. 1, there is shown a golf ball having at least
three layers according to the present invention, which has a solid
core 1, an intermediate layer 2 for covering the solid core 1, and
a cover 3 for covering the intermediate layer 2. Each of the solid
core, intermediate layer, and cover of the golf ball shown in the
FIGURE is of a single layer structure; however, it may be of a
multi-layer structure having two or more layers as needed. When the
solid core, intermediate layer, or cover, each has a plurality of
layers, the multi-layers of the solid core, intermediate layer, or
cover is configured to satisfy a requirement of the structure of
the solid core, intermediate layer, or cover as a whole.
The solid core 1 of the present invention may be made from a known
core material, typically, a rubber composition. In particular,
polybutadiene, preferably cis-1,4-polybutadiene having at least 40%
or more of a cis-structure may be used as a base rubber of the
solid core 1.
A cross-linking agent, for example, a zinc salt or a magnesium salt
of an unsaturated fatty acid, such as zinc methacrylate or zinc
acrylate, or an ester compound such as
trimethylolpropanetrimethacrylate may be added to the above rubber
composition. In particular, zinc acrylate is preferably added
because it has a high repulsion characteristic. The added amount of
the cross-linking agent may be in a range of 10 to 35 parts by
weight on the basis of 100 parts by weight of the base rubber.
A vulcanizing agent such as dicumyl peroxide, or a mixture of
dicumyl peroxide and
1,1-bis(t-butylperoxy)-3,3,5-trimethylcyclohexane may be added to
the above rubber composition. The added amount of the vulcanizing
agent may be in a range of 0.1 to 5 parts by weight on the basis of
100 parts by weight of the base rubber. Dicumyl peroxide is
commercially available, for example, by NOF CORPORATION under the
trade name of "Percumyl D".
A filler such as zinc oxide, barium sulfate, and the like may be
further added to the rubber composition as needed for adjustment of
the specific gravity. The added amount of these agents may be in a
range of 10 to 50 parts by weight on the basis of 100 parts by
weight of the base rubber. An anti-aging agent is also added.
The solid core of the present invention can be made from a material
other than the above-described rubber composition insofar as it
satisfies a hardness requirement of the solid core (compression
deflection, difference in JIS-C hardness) to be described later.
For example, the solid core may be made from a thermoplastic resin
exemplified as a material for forming the intermediate layer to be
described later.
The solid core can be made from the above-described rubber
composition by kneading the rubber composition by using a usual
kneader (for example, Banbury mixer, kneader or roll mill), and
compression-molding a resultant compound by using a core mold. The
solid core can be also made from a resin material by injection
molding.
The solid core of the present invention is specified such that the
compression deflection and the JIS-C hardness of the solid core are
optimized as described below. First, the compression deflection of
the solid core and a relationship between the compression
deflection of the core and the compression deflection of a sphere
composed the intermediate layer (to be described later) and the
solid core covered therewith should be optimized. The compression
deflection used in the present invention means a compression
deflection when a load range of initial 98 N (10 kgf) to final 1275
N (130 kgf) is applied.
The compression deflection of the solid core of the present
invention is specified to be equal to or more than 3.0 mm,
preferably equal to or more than 3.3 mm. If the compression
deflection of the solid core is less than 3.0 mm, since the solid
core becomes excessively hard, the player's feeling of hitting the
golf ball becomes rigid, and the spin property of the golf ball
upon driver shot is increased to shorten the flying distance of the
golf ball. Further, the upper limit of the compression deflection
of the solid core may be equal to or less than 6.00 mm, preferably
equal to or less than 5.0 mm. If the compression deflection of the
solid core is more than 6.0 mm, since the solid core becomes
excessively soft and thereby it fails to exhibit a sufficient
repulsion characteristic, with a result that the flying distance of
the golf ball is shortened.
The solid core of the present invention is specified such that the
JIS-C hardness of the surface of the solid core is larger than that
of the center of the solid core, and that the difference in JIS-C
hardness between the surface and the center of the solid core is
equal to or more than 5, preferably equal to or more than 8. If the
difference in JIS-C hardness between the surface and the center of
the solid core is less than 5, the spin property of the golf ball
becomes excessively large, to shorten the flying distance of the
golf ball. In addition, the upper limit of the difference in JIS-C
hardness between the surface and the center of the solid core may
be equal to or less than 22, preferably equal to or less than
20.
The diameter of the solid core of the present invention is not
particularly limited but may be in a range of 32.0 to 38.7 mm,
preferably 35.0 to 37.0 mm. The weight of the solid core may be in
a range of 20 to 36 g, preferably 25 to 32 g.
The intermediate layer 2 of the present invention is a relatively
soft layer which is mainly made from a thermoplastic resin and
which has a high repulsion characteristic. The intermediate layer 2
is formed between the solid core 1 and the cover 3, as shown in
FIG. 1.
As the thermoplastic resin for forming the intermediate layer,
there may be used a thermoplastic elastomer. Specific examples of
the thermoplastic elastomers may include various thermoplastic
elastomers such as a polyester based elastomer, a polyamide based
elastomer, a polyurethane based elastomer, an olefin based
elastomer, and a styrene based elastomer. These thermoplastic
resins are commercially available, for example, under the trade
names "Hytrel" (sold by Du Pont-Toray Co., Ltd.), "Pelprene" (sold
by Toyobo Co., Ltd.), "Pebax" (sold by Toray Industries, Inc.),
"Pandex" (sold by Dainippon Ink & Chemicals, Incorporated),
"Santoplane" (sold by Monsanto Company), and "Toughtec" (sold by
Asahi Chemical industry Co., Ltd.).
Various kinds of additives such as an inorganic filler of a
suitable amount may be added to the thermoplastic resin. As the
inorganic filler, there may be used barium sulfate or titanium
dioxide. The inorganic filler may be subjected to surface treatment
so as to be easily diffused in the thermoplastic resin.
The intermediate layer of the present invention can be formed by a
known molding process, such as an injection molding process or a
compression molding process. The injection molding process involves
placing a previously formed solid core in a mold for injection
molding, and injecting the above-described material in the mold.
The compression molding process involves forming a pair of cup
halves made from the above-described material, surrounding a
previously formed solid core with the cup halves, and pressing the
cup halves to the solid core in the mold while heating the
mold.
The Shore D hardness of the intermediate layer of the present
invention is specified to be in a range of 45 to 55, preferably 47
to 53. If the Shore D hardness of the intermediate layer is less
than 45, since the intermediate layer becomes excessively soft, the
spin property of the golf ball upon driver shot becomes excessively
large, to shorten the flying distance of the golf ball, and if it
is more than 55, since the intermediate layer becomes excessively
hard, the player's feeling of hitting the golf ball is
degraded.
The specific gravity of the intermediate layer of the present
invention is specified to be equal to or less than 1.2, preferably
equal to or less than 1.17. If the specific gravity of the
intermediate layer is more than 1.2, the repulsion characteristic
thereof becomes insufficient, with a result that the flying
distance of the golf ball is shortened. The lower limit of the
specific gravity of the intermediate layer may be equal to more
than 0.96, preferably equal to or more than 1.0.
According to the present invention, the gage of the intermediate
layer is specified to be made as thin as 2.0 mm or less, preferably
1.7 mm or less. If the gage of the intermediate layer is more than
2.0 mm, it may fail to improve the player's feeling of hitting the
golf ball and to lengthen the flying distance of the golf ball. The
lower limit of the gage of the intermediate layer may be equal to
or less than 0.2 mm, preferably equal to or less than 0.8 mm.
The multi-piece solid golf ball of the present invention is
specified such that a ratio of the compression deflection of a
sphere composed of the intermediate layer and the solid core
covered therewith when a load range of initial 10 kgf to final 130
kgf is applied to the compression deflection of the solid core when
a load range of initial 10 kgf to final 130 kgf is applied
(compression deflection of sphere/compression deflection of solid
core) is optimized, that is, set at a value being more than 0.900
and less than 0.970 [0.900<(compression deflection of
sphere/compression deflection of solid core)<0.970], preferably
more than 0.910 and less than 0.960 [0.910<(compression
deflection of sphere/compression deflection of solid
core)<0.960]. If the above ratio in compression deflection is
equal to or less than 0.900, the player's feeling of hitting the
golf ball upon putter shot or approach shot such as iron shot is
degraded, and if it is equal to or more than 0.970, the spin
property of the golf ball upon driver shot becomes excessively
large, to shorten the flying distance of the golf ball.
The golf ball of the present invention includes, as shown in FIG.
1, the cover 3 as the outermost portion of the golf ball. As
described above, the cover of the present invention may be of a
single layer structure or a multi-layer structure having two or
more layers. The multi-layer cover has at least one layer
constituting the outermost layer and one or more layers formed
inside the outermost layer. According to the present invention, it
is defined that even in such a multi-layer cover, the plurality of
layers constituting the cover satisfy a requirement of the cover as
a whole, and particularly, any of the one or more layers formed
inside the outermost layer is distinguished from the
above-described intermediate layer.
The cover of the present invention can be formed from a known
material mainly containing a thermoplastic resin. As the cover
material, there may be used an ionomer resin which is commercially
available, for example, under the trade name "Himilan" (sold by Du
Pont-Mitsui Polychemicals Co., Ltd.), "Surlyn" (sold by Du Pont De
Nemours & Company), or "Iotec" (sold by Exxon Chemical Japan
Ltd.)
Various additives such as an inorganic filler of a suitable amount
may be added to the cover material. As the inorganic filler, there
may be used the above-described filler added to the intermediate
layer.
Like the intermediate layer, the cover can be formed from the
above-described material by injection molding or compression
molding.
According to the present invention, the thickness of the cover is
specified to be in a range of 1.6 to 2.3 mm, preferably 1.8 to 2.1
mm. If the thickness of the cover is less than 1.6 mm, the
durability of the cover is degraded, tending to cause cracks, and
if it is more than 2.3 mm, the player's feeling of hitting the golf
ball is degraded.
The Shore D hardness of the cover is specified to be equal to or
more than 60, preferably equal to or more than 62. If the Shore D
hardness of the cover is less than 60, the repulsion characteristic
thereof becomes insufficient, with a result that the flying
performance of the golf ball is degraded. The upper limit of the
Shore D hardness of the cover may be equal to or more than 68,
preferably equal to or more than 65. If the Shore D hardness of the
cover is more than 68, the player's feeling of hitting the golf
ball may become rigid.
With respect to the multi-piece solid golf ball of the present
invention having the above-described configuration, the compression
deflection of the ball may be in a range of 2.5 to 3.5 mm,
preferably 2.7 to 3.2 mm. The multi-piece solid golf ball of the
present invention has on its surface a large number of dimples, the
shapes and arrangement of which may be the same as those of dimples
of a known golf ball. In addition, the multi-piece solid golf ball
of the present invention may be subjected to a known surface finish
treatment such as painting or stamping.
The multi-piece golf ball of the present invention can be produced
with its diameter and weight specified under the golf rule,
specifically, the diameter being in a range of 42.67 mm or more,
and the weight being in a range of 45.93 g or less.
As described above, the multi-piece solid golf ball of the present
invention is capable of giving a player a desirable soft feeling of
hitting the golf ball upon putter shot or approach shot and also a
desirable feeling of hitting the golf ball upon driver shot, and is
capable of improving the flying performance of the golf ball.
The present invention will be more clearly understood by way of,
while not limited thereto, the following examples:
EXAMPLES
A rubber compound having the formulation shown in Table 1 was
introduced in a specific mold to form a solid core having a
difference in JIS-C hardness shown in Table 1.
The solid core thus formed was sequentially covered with an
intermediate layer and a cover by using materials shown in Table 2
in accordance with conditions shown in Table 3 to produce a golf
ball having on its surface dimples with the same shapes and
arrangement.
In this way, the golf ball samples in Examples 1 to 4 and
Comparative Examples 1 to 8 were obtained.
Note that characters "Hytrel", "Surlyn", "Himilan", and "Pelprene"
in Table 2 designate the following materials:
"Hytrel": polyester based thermoplastic elastomer by Du Pont-Toray
Co., Ltd.
"Surlyn": ionomer resin by Du Pont De Nemours & Company
"Himilan": ionomer resin by Du Pont-Mitsui Polychemicals Co.
Ltd.
"Pelprene": polyester based thermoplastic elastomer by Toyobo Co.,
Ltd.
For each of the golf ball samples, the compression deflection was
measured, and the hitting performance, player's feeling, and the
durability against cracks were evaluated in accordance with the
following testing methods:
Compression Deflection
The compression deflection of each golf ball sample was measured as
a deformation (mm) of the ball under a load of 1275 N (130 kgf)
based on an initial load of 98 N (10 kgf).
Hitting Performance
Each golf ball sample was hit at a head speed of 35 m/s by a swing
robot on which a driver (#W1) was mounted, and the carry, total
flying distance, and spin property of the ball were measured.
The flying performance of the ball was evaluated under the
following criterion:
.largecircle.: good (total distance: 155 m or more)
X: poor (total distance: less than 155 m)
Player's Feeling
Each golf ball sample was hit with the driver (#W1) and putter, and
the player's feeling was evaluated under the following criterion:
.largecircle.: good (soft) feeling .DELTA.: slightly rigid X: poor
Durability Against Cracks
Each golf ball sample was repeatedly hit at a head speed of 40 m/s
by the swing robot on which the driver (#W1) was mounted, and the
number of hitting of the ball until the ball was cracked was
evaluated under the following criterion: .largecircle.: good
durability against cracks (no crack occurs after hitting is
repeated by 200 times or more) X: poor durability against cracks
(cracks occur after hitting is repeated by less than 150 times)
The results are shown in Table 3.
As is apparent from Table 3, each of the samples in Comparative
Examples 1 to .[.4 and 6.]. .Iadd.5 .Iaddend.and 7 .Iadd.and
8.Iaddend. is poor in flying performance, and the sample in
Comparative Example .[.5.]. .Iadd.6 .Iaddend.is good in flying
performance, and player's feeling upon each of driver shot and
putter shot, but is poor in durability against cracks. On the
contrary, each of the samples in Examples 1 to 4 is good in flying
performance, player's feeling upon each of driver shot and putter
shot, and durability against cracks. Further, the sample in each of
Examples 1 to 4 is smaller in spin property than that of each of
Comparative Examples 1 to .Iadd.5 and 7 and .Iaddend.8.
While the preferred embodiments of the present invention have been
described using the specific terms, such description is for
illustrative purposes only, and it is to be understood that changes
and variations may be made without departing from the spirit and
scope of the following claims.
TABLE-US-00001 TABLE 1 Example Comparative Example 1 2 3 4 1 2 3 4
5 6 7 8 Component for Core Polybutadiene 100 100 100 100 100 100
100 100 100 100 100 100 (parts by weight) Zinc Acrylate 25 27.4
24.4 25 28.7 31.6 26.8 27.6 27.6 25 28.7 27.4 Peroxide (*) 1.2 1.2
1.2 1.2 1.2 1.2 1.2 1.2 1.2 1.2 1.2 1.2 Anti-aging Agent 0.2 0.2
0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 Barium Sulfate 25.2 24.2
25.4 18.8 18.9 17.7 29.1 24.1 23.7 19.9 23.8 13.- 7 Zinc Oxide 5 5
5 5 5 5 5 5 5 5 5 5 Zinc Salt of 0.2 0.2 0.2 0.2 0.1 0.1 0.2 0.2
0.2 0.2 0.2 0.2 Pentachlorothiophenol Vulcanizing Primary
Temperature 155 155 155 155 155 155 155 155 155 155 15- 5 155
Condition Vulcanization (.degree. C.) Time 15 15 15 15 15 15 15 15
30 15 15 15 (Minute) Secondary Temperature 170 Vulcanization
(.degree. C.) Time 10 (Minute) Hardness A: Core Surface 73 78 71 74
79 82 77 78 71 73 79 78 (JIS-C) B: Core Center 61 64 61 60 65 68 63
64 68 61 65 64 (JIS-C) A-B 12 14 10 14 14 14 14 14 3 12 14 14
(JIS-C) (*) mixture of Percumyl D (NOF CORPORATION) and Perhexa
3M-40 (NOF CORPORATION) at weight ratio of 1:1
TABLE-US-00002 TABLE 2 {circle around (1)} {circle around (2)}
{circle around (3)} {circle around (4)} {circle around (5)} {circle
around (6)} {circle around (7)} Component for Himilan 1706 50 25
Intermediate Himilan 1650 50 Layer/Cover Himilan 1557 50 (parts by
Himilan 1605 50 25 weight) Himilan 1601 50 Surlyn 8120 50 Hytrel
4767 100 Hytrel 4047 100 Hytrel 3078 50 Pelprene P150B 50 Pelprene
P150M 50 Titanium Dioxide 5.6 0 0 0 5.6 5.6 0 Physical Specific
Gravity 0.985 1.020 1.165 1.33 0.965 0.985 1.210 Property Resin
Hardness 63 51 52 43 60 55 54 (Shore D)
TABLE-US-00003 TABLE 3 Example Comparative Example 1 2 3 4 1 2 3 4
5 6 7 8 Core Weight (g) 28.71 27.55 27.64 27.82 27.03 27.03 28.2
27.55 27.55 29.54 26.45 26.2- 4 Compression 4.20 3.75 4.32 4.19
3.49 2.94 3.85 3.75 3.70 4.20 3.50 3.75 Deflection (mm) Inter- Kind
{circle around (2)} {circle around (2)} {circle around (2)} {circle
around (3)} {circle around (4)} {circle around (4)} {circle around
(5)} {circle around (2)} {circle around (3)} {circle around (2)}
{circle around (2)} {circle around (7)} mediate Weight (g) 34.97
34.63 34.65 35.18 35.15 35.15 35.15 34.63 34.65 37.41 32.75 34.- 63
Layer Compression 4.01 3.47 3.93 3.95 3.18 2.05 3.30 3.47 3.40 4.00
3.32 3- .39 Deflection (mm) (*) Gage (mm) 1.42 1.63 1.62 1.46 1.68
1.68 1.68 1.63 1.63 1.70 1.50 1.63 Cover Type {circle around (1)}
{circle around (1)} {circle around (1)} {circle around (1)} {circle
around (1)} {circle around (1)} {circle around (1)} {circle around
(6)} {circle around (1)} {circle around (1)} {circle around (1)}
{circle around (1)} Thickness 2.10 2.14 2.13 2.07 2.07 2.07 2.07
2.14 2.13 1.50 2.40 2.14 (mm) Ratio of Intermediate 0.955 0.925
0.910 0.943 0.911 1.003 0.857 0.925 0.91- 9 0.952 0.949 0.904
Compres- Layer (*)/ sion Deflec- tion Ball Weight (g) 45.21 45.08
45.07 45.25 45.27 45.27 45.30 45.08 45.30 45.30 45.30 45.- 30
Outside 42.70 42.70 42.70 42.70 42.70 42.70 42.70 42.70 42.70 42.70
42.70- 42.70 Diameter (mm) Compression 3.03 2.72 3.03 3.04 2.73
2.60 2.75 2.82 2.79 3.12 2.65 2.65 Deflection (mm) Driver Carry (m)
141.8 141.8 142.5 142.1 142.2 142.0 140.5 138.4 141.4 141.8 141.5
140- .8 #W1 Total (m) 155.7 156.2 155.1 155.9 153.6 152.5 152.1
149.5 152.9 155.3 - 153.8 153.9 (HS35) Flying .largecircle.
.largecircle. .largecircle. .largecircle. X X - X X X .largecircle.
X X Performance Spin (rpm) 3428 3562 2458 3366 3743 3798 3565 3722
3717 3479 3762 3605 Feeling .largecircle. .largecircle.
.largecircle. .largecircle. .largecir- cle. .DELTA. .DELTA.
.largecircle. .largecircle. .largecircle. .DELTA. .la- rgecircle.
Putter Feeling .largecircle. .largecircle. .largecircle.
.largecircle. .la- rgecircle. .largecircle. X .largecircle.
.largecircle. .largecircle. X .la- rgecircle. Durability Against
.largecircle. .largecircle. .largecircle. .largecircle.-
.largecircle. .largecircle. .largecircle. .largecircle.
.largecircle. X .- largecircle. .largecircle. Cracks (*)
compression deflection of sphere composed of intermediate layer and
core covered therewith
* * * * *