U.S. patent application number 09/998662 was filed with the patent office on 2003-05-01 for golf ball.
This patent application is currently assigned to BRIDGESTONE SPORTS CO., LTD.. Invention is credited to Hayashi, Junji, Ichikawa, Yasushi, Shimizu, Yasumasa, Takesue, Rinya, Yamagishi, Hisashi.
Application Number | 20030083154 09/998662 |
Document ID | / |
Family ID | 19141073 |
Filed Date | 2003-05-01 |
United States Patent
Application |
20030083154 |
Kind Code |
A1 |
Yamagishi, Hisashi ; et
al. |
May 1, 2003 |
Golf ball
Abstract
A golf ball includes a solid core, and a cover having one layer
or two or more layers provided to directly cover the solid core or
cover the solid core via an intermediate layer. At least one layer
of the cover is taken as a high hardness cover layer which is made
from a base resin containing an inorganic filler in an amount of 5
to 40 parts by weight on the basis of 100 parts by weight of the
base resin and which has a Shore D hardness in a range of 66 to 80.
With this configuration, the golf ball can exhibit a high carrying
performance, a desirable very soft feeling of hitting, and an
excellent durability against continuous hitting.
Inventors: |
Yamagishi, Hisashi;
(Chichibu-shi, JP) ; Hayashi, Junji;
(Chichibu-shi, JP) ; Ichikawa, Yasushi;
(Chichibu-shi, JP) ; Takesue, Rinya;
(Chichibu-shi, JP) ; Shimizu, Yasumasa;
(Chichibu-shi, JP) |
Correspondence
Address: |
SUGHRUE, MION, ZINN, MACPEAK & SEAS, PLLC
2100 Pennsylvania Avenue, N.W.
Washington
DC
20037-3213
US
|
Assignee: |
BRIDGESTONE SPORTS CO.,
LTD.
|
Family ID: |
19141073 |
Appl. No.: |
09/998662 |
Filed: |
December 3, 2001 |
Current U.S.
Class: |
473/371 ;
473/378 |
Current CPC
Class: |
C08K 3/30 20130101; C08L
2205/02 20130101; C08L 23/0876 20130101; A63B 37/12 20130101; A63B
37/0003 20130101; A63B 37/0031 20130101; A63B 37/0054 20130101;
A63B 37/02 20130101; C08L 23/0876 20130101; C08L 9/00 20130101;
C08L 2666/06 20130101; C08K 3/30 20130101 |
Class at
Publication: |
473/371 ;
473/378 |
International
Class: |
A63B 037/02; A63B
037/12 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 23, 2001 |
JP |
2001-324336 |
Claims
1. A golf ball comprising: a solid core; and a cover having one
layer or two or more layers provided to directly cover said solid
core or cover said solid core via an intermediate layer; wherein at
least one layer of said cover is taken as a high hardness cover
layer which is made from a base resin containing an inorganic
filler in an amount of 5 to 40 parts by weight on the basis of 100
parts by weight of said base resin and which has a Shore D hardness
in a range of 66 to 80.
2. A golf ball according to claim 1, wherein said high hardness
cover layer is an outermost cover layer.
3. A golf ball according to claim 1 or 2, wherein said base resin
for forming said high hardness cover layer has a Shore D hardness
in a range of 65 or more.
4. A golf ball according to any one of claims 1 to 3, wherein the
Shore D hardness of said high hardness cover layer is higher than
the Shore D hardness of said base resin by 1 or more.
5. A golf ball according to any one of claims 1 to 4, wherein said
inorganic filler contained in said high hardness cover layer is
titanium dioxide and/or barium sulfate.
6. A golf ball according to any one of claims 1 to 5, wherein said
high hardness cover layer contains titanium dioxide as said
inorganic filler in an amount of 2 parts by weight or more.
7. A golf ball according to any one of claims 1 to 6, wherein a
deformed amount of said solid core, measured by applying a load of
980 N thereto, is in a range of 4.0 to 6.5 mm.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates to a golf ball capable of
giving a soft feeling of hitting the ball to a golf player, and
enhancing the carrying performance of the ball.
[0002] In recent years, soft golf balls for giving soft feeling of
hitting the balls to golf players have been increasingly required.
Such soft golf balls, however, have also been required to have a
high resilience enough to enhance a carrying performance and to
have a high durability.
SUMMARY OF THE INVENTION
[0003] An object of the present invention is to provide a golf ball
capable of giving a soft feeling of hitting the ball, and having a
high resilience enough to enhance a carrying performance, and a
high durability.
[0004] The present inventors have earnestly studied a soft golf
ball including a solid core and a cover, and found that even if a
deformed amount of a solid core, measured by applying a load of 980
N thereto, is in a range of 4.0 to 6.5 mm, a golf ball having a
high resilience, a low spin, a high hitting angle, a high carrying
performance, and a high durability can be obtained by providing a
high hardness cover layer which is made from a base resin
containing an inorganic filler in an amount of 5 to 40 parts by
weight on the basis of 100 parts by weight of the base resin and
which has a Shore D hardness in a range of 66 to 80, wherein the
high hardness cover layer is preferably taken as an outermost cover
layer. On the basis of such knowledge, the present invention has
been accomplished.
[0005] To achieve the above object, according to an aspect of the
present invention, there is provided a golf ball including: a solid
core; and a cover having one layer or two or more layers provided
to directly cover the solid core or cover the solid core via an
intermediate layer; wherein at least one layer of the cover is
taken as a high hardness cover layer which is made from a base
resin containing an inorganic filler in an amount of 5 to 40 parts
by weight on the basis of 100 parts by weight of the base resin and
which has a Shore D hardness in a range of 66 to 80.
[0006] The high hardness cover layer is preferably an outermost
cover layer.
[0007] The base resin for forming the high hardness cover layer
preferably has a Shore D hardness in a range of 65 or more.
[0008] The Shore D hardness of the high hardness cover layer is
preferably higher than the Shore D hardness of the base resin by 1
or more.
[0009] The inorganic filler contained in the high hardness cover
layer is preferably titanium dioxide and/or barium sulfate.
[0010] The high hardness cover layer preferably contains titanium
dioxide as the inorganic filler in an amount of 2 parts by weight
or more.
[0011] A deformed amount of the solid core, measured by applying a
load of 980 N thereto, is preferably in a range of 4.0 to 6.5
mm.
DETAILED DESCRIPTION OF THE INVENTION
[0012] The present invention will be hereinafter described in
detail.
[0013] A golf ball of the present invention is a solid golf ball
including a solid core and a cover.
[0014] The solid core can be produced by vulcanizing a rubber
composition. The rubber composition may contain a main rubber
component, an unsaturated carboxylic acid and/or a metal salt
thereof as a crosslinking agent, and an organic peroxide.
[0015] As the above-described main rubber component, there is
preferably used polybutadiene, particularly, cis-1,4-polybutadiene.
In this case, another diene based rubber, such as styrene-butadiene
rubber (SBR), natural rubber, isoprene rubber, or
ethylene-propylene-diene rubber (EPDM) may be suitably mixed with
polybutadiene as a main component of the main rubber component, as
needed.
[0016] Examples of the unsaturated carboxylic acids, each of which
is usable as the crosslinking agent of the main rubber component,
may include acrylic acid, metacrylic acid, maleic acid, fumaric
acid. In particular, acrylic acid and metacrylic acid are
preferably used.
[0017] Examples of the metal salts of unsaturated carboxylic acids
may include zinc salts and magnesium salts of unsaturated aliphatic
acids, for example, zinc metacrylate and zinc acrylate. In
particular, zinc acrylate is preferably used.
[0018] The content of the unsaturated carboxylic acid and/or metal
salt thereof may be set, on the basis of 100 parts (parts by
weight, the same applying hereinafter) of the main rubber
component, in a range of 10 parts or more, preferably, 15 parts or
more, more preferably, 20 parts or more, with the upper limit being
set in a range of 50 parts or less, preferably, 45 parts or less,
more preferably, 40 parts or less, most preferably, 35 parts or
less. If the content is excessively small, the resilience is
reduced, while if excessively large, the solid core becomes
excessively hard, thereby often causing undesirable player's
feeling of hitting of the golf ball.
[0019] As the organic peroxide, there can be used a commercial
product such as "Percumyl D" (sold by NOF CORPORATION), "Perhexa
3M" (sold by NOF CORPORATION), "Luperco 231XL" (sold by Elf Atochem
Japan). Two kinds or more organic peroxides may be used in
combination, as needed.
[0020] The content of the organic peroxide may be set, on the basis
of 100 parts of the main rubber component, in a range of 0.1 part
or more, preferably, 0.3 part or more, more preferably, 0.5 part or
more, most preferably, 0.7 part or more, with the upper limit being
set in a range of 5 parts or less, preferably, 4 parts or less,
more preferably, 3 parts or less, most preferably, 2 parts or less.
If the content is excessively large or small, the resilience,
feeling of hitting the golf ball, and durability may not be
obtained.
[0021] The rubber composition of the present invention may contain,
in addition to the above-described essential components, an
inorganic filler for adjusting a specific gravity of the rubber
composition, as needed. Examples of the inorganic fillers may
include zinc oxide, barium sulfate, and calcium carbonate. In order
to obtain a suitable weight and a desirable resilience, the content
of the inorganic filler may be set, on the basis of 100 parts of
the main rubber component, in a range of 1 part or more,
preferably, 3 parts or more, more preferably, 5 parts or more, most
preferably, 7 parts or more, with the upper limit being set in a
range of 60 parts or less, preferably, 50 parts or less, more
preferably, 45 parts or less, most preferably, 40 parts or
less.
[0022] An antioxidant may be further added to the rubber
composition of the present invention, as needed. As the
antioxidant, there can be used a commercial product such as "NOCRAC
NS-6, NS-30" (sold by Ouchi-Sinko Chemical Industrial Co., Ltd.),
or "Yoshinox 425" (Yoshitomi Pharmaceutical Co., Ltd.). In order to
obtain desirable resilience and durability, the content of the
antioxidant may be set, on the basis of 100 parts of the main
rubber component, in a range of 0 part or more, preferably, 0.05
part or more, more preferably, 0.1 part or more, most preferably,
0.2 part or more, with the upper limit being set in a range of 3
parts or less, preferably, 2 parts or less, more preferably, 1 part
or less, most preferably, 0.5 part or less.
[0023] The rubber composition of the present invention may contain
an organic sulfur compound, as needed. Examples of the organic
sulfur compounds may include thiophenol, thionaphthol, halogenated
thiophenol, or metal salts thereof, more concretely, zinc salts of
pentachlorothiophenol, pentafluorothiophenol, pent
abromothiophenol, and parachlorothiophenol; and diphenyl
polysulfide, dibenzil polysulfide, dibenzoil polysulfide,
dibenzothiazoil polysulfide, and dithiobenzoil polysulfide, each of
which has the sulfur number of 2 to 4. In particular, a zinc salt
of pentachlorothiophenol or diphenyl disulfide is preferably used.
The content of the organic sulfur compound may be set, on the basis
of 100 parts of the main rubber component, in a range of 0.05 part
or more, preferably, 0.1 part or more, more preferably, 0.2 part or
more, with the upper limit being set in a range of 5 parts or less,
preferably, 4 parts or less, more preferably, 3 parts or less, most
preferably, 2.5 parts or less.
[0024] The solid core of the present invention can be formed by
vulcanizing and hardening the above-described rubber composition by
a known process. For example, a vulcanizing temperature may be set
in a range of 100 to 200.degree. C., and a vulcanizing time be set
in a range of 10 to 40 min.
[0025] According to the present invention, the hardness of the
solid core, which is expressed in a deformed amount of the solid
core measured by applying a load of 980 N (100 kg) thereto, may be
set in a range of 4.0 mm or more, preferably, 4.2 mm or more, more
preferably, 4.3 mm or more, with the upper limit being set in a
range of 6.5 mm or less, preferably, 6.0 mm or less, more
preferably, 5.2 mm or less. If the flexural amount (deformed
amount) is excessively small, the feeling of hitting the golf ball
becomes harder, and particularly, the spin of the ball becomes
excessively high at the time of long-shot with a driver when the
ball is liable to be largely deformed, to reduce the carry of the
ball, while if excessively large, the feeling of hitting the ball
becomes dull, the carry of the ball is reduced because of the
insufficient resilience of the ball, and the durability against
cracking due to repeated hitting is degraded.
[0026] In addition, the deformed amount of the core can be
determined by suitably selecting the kinds and amounts of
components of the rubber composition and the vulcanizing
condition.
[0027] The diameter of the solid core of the present invention may
be set in a range of 38.0 mm or more, preferably, 38.5 mm or more,
more preferably, 38.7 mm or more, most preferably, 38.9 mm or more,
with the upper limit being set in a range of 41.0 mm or less,
preferably, 40.7 mm or less, more preferably, 40.3 mm or less, most
preferably, 40.1 mm or less.
[0028] The specific gravity of the solid core may be set in a range
of 1.000 or more, preferably, 1.050 or more, more preferably, 1.100
or more, with the upper limit being set in a range of 1.300 or
less, preferably, 1.250 or less, more preferably, 1.200 or
less.
[0029] The solid core may be of one layer structure or a
multi-layer structure having two or more layers insofar as the
deformed amount of the solid core satisfy the above-described
requirement thereof.
[0030] The cover provided to cover the core may be of a one-layer
structure or a multi-layer structure having two or more layers.
According to this embodiment, however, at least one layer,
particularly, an outermost layer is made from a base resin which
contains an inorganic filler in an amount of 5 to 40 parts by
weight on the basis of 100 parts of the base resin and which has a
Shore D hardness in a range of 66 to 80.
[0031] The base resin for forming the high hardness cover layer is
preferably an ionomer resin, and preferably has a Shore D hardness
in a range of 65 or more, more preferably, 66 or more.
[0032] Examples of the inorganic fillers contained in the base
resin may include titanium dioxide and barium sulfate. The content
of the inorganic filler may be set, on the basis of 100 parts of
the base resin, in a range of 5 parts or more, preferably, 8 parts
or more, more preferably, 10 parts or more, with the upper limit
being set in a range of 40 parts or less, preferably, 38 parts or
less, more preferably, 35 parts or less, most preferably, 30 parts
or less. If the content of the inorganic filler is excessively
small, the effect of the present invention cannot be sufficiently
obtained, and therefore, the durability may be degraded, while if
excessively large, the resilience may be reduced and the rate of
occurrence of failures at the time of molding the base resin be
increased. In addition, the content of titanium dioxide may be set,
on the basis of 100 parts of the base resin, in a range of 2 parts
or more, preferably, 3 parts or more.
[0033] A UV absorbent, an oxidation inhibitor, a dispersant, and a
coloring agent can be added to the cover material, as needed. A
specific gravity of the high hardness cover layer may be set in a
range of 1.020 or more, preferably, 1.030 or more, more preferably,
1.040 or more, with the upper limit being set in a range of 1.110
or less, preferably, 1.090 or less.
[0034] According to the golf ball of the present invention, the
Shore D hardness of the high hardness cover layer may be set in a
range of 66 or more, preferably, 67 or more, more preferably, 68 or
more, with the upper limit being set in a range of 80 or less,
preferably, 78 or less, more preferably, 75 or less. If the Shore D
hardness of the high hardness cover layer is excessively low, the
resilience may become insufficient and the carrying performance may
be degraded, while if excessively high, the durability may be
degraded.
[0035] In this case, by adding the inorganic filler to the base
resin, the Shore hardness of the high hardness cover layer becomes
higher than the Shore D hardness of the base resin by 1 or more,
particularly, 2 or more.
[0036] If the cover has a one-layer structure, then the cover is
composed of the above-described high hardness cover layer, and if
the cover has a multi-layer structure having two or more layers,
then at least one layer, preferably, the outermost layer of the
cover is taken as the high hardness cover layer. In this case, for
the cover having the two or more layers, the hardness of each of
the cover layers other than the high hardness cover layer is
preferably lower than the hardness of the high hardness cover layer
and higher than the surface hardness of the core. The base resin
for forming the cover layers other than the high hardness cover
layer may be a known cover material, for example, an ionomer resin,
or a polyurethane based, polyamide based, or polyester based
thermoplastic elastomer. These materials may be used singly or in
combination of two or more kinds. As these ionomer resin and
thermoplastic elastomer, commercial products can be used.
[0037] For the cover composed of only the single high hardness
cover layer, a thickness of the high hardness cover layer may be
set in a range of 1.0 mm or more, preferably, 1.1 mm or more, with
the upper limit being set in a range of 2.3 mm or less, preferably,
2.2 mm or less, more preferably, 2.1 mm or less, most preferably,
2.0 mm or less. For the cover of the multi-layer structure having
two or more layers, a thickness of the high hardness cover layer
may be set in a range of 1.0 mm or more, preferably, 1.1 mm or
more, with the upper limit being set in a range of 2.3 mm or less,
preferably, 2.2 mm or less, more preferably, 2.1 mm or less, most
preferably, 2.0 mm or less. The total thickness of the cover may be
set in a range of 1.3 mm or more, preferably, 1.5 mm or more, with
the upper limit being set in a range of 6.0 mm or less, preferably,
5.0 mm or less.
[0038] If the thickness of the high hardness cover layer is
excessively thin, the durability may be degraded, while if
excessively thick, the feeling of hitting may become hard or
dull.
[0039] The cover of the golf ball of the present invention can be
formed by a known process of putting the solid core in a specific
mold for injection molding, and injection-molding the cover
material. Alternatively, the cover can be formed by preparing a
pair of cup-halves made from the cover material, putting the solid
core covered with the cup-halves in a specific mold, and
press-molding the resultant solid core covered with the
cup-halves.
[0040] Like a general golf ball, the golf ball of the present
invention has in the cover surface a large number of dimples. The
total number of the dimples may be set in a range of 350 or more,
preferably, 370 or more, more preferably, 390 or more, with the
upper limit being set in a range of 500 or less, preferably, 480 or
less, more preferably, 450 or less. As the geometrical arrangement
of the dimples, there can be adopted an octahedron or icosahedron
arrangement. The pattern of the dimple is not limited to a circular
shape but may be a square, hexagonal, pentagonal, or triangular
shape.
[0041] The golf ball of the present invention can be produced with
its diameter and weight specified under a golf rule for golf games.
Concretely, the diameter of the golf ball can be set in a range of
42.67 mm or more, with the upper limit being set in a range of 44.0
mm or less, preferably, 43.5 mm or less, more preferably, 43.0 mm
or less, and the weight of the golf ball can be set in a range of
45.93 g or less, with the lower limit being set in a range of 44.5
g or more, preferably, 44.8 g or more, more preferably, 45.0 or
more.
[0042] As described above, the present invention can provide a golf
ball having a high carrying performance, a desirable very soft
feeling of hitting, and an excellent durability against continuous
hitting.
EXAMPLE
[0043] The present invention will be more clearly understood by way
of, while not limited thereto, the following examples and
comparative examples. In the examples, "parts" designate parts by
weight.
Examples 1 to 4 and Comparative Examples 1 to 3
[0044] A two-piece solid golf ball including a solid core and a
cover was produced from each of rubber compositions shown in Table
1 by a known process.
[0045] Each golf ball thus obtained was evaluated in terms of
carrying performance, durability against continuous hitting, and
feeling of hitting in accordance with the following manners. The
results are shown in Table 1. It is to be noted that in Table 1,
"Himilan" is an ionomer resin sold by Du Pont-Mitsui Polychemicals
Co., Ltd.
1 TABLE 1 Comparative Example Example 1 2 3 4 1 2 3 Composition
Cis-1,4-Polybutadiene 100 100 100 100 100 100 100 of Core Zinc
acrylate 22.8 21.5 17.0 18.3 22.8 27.3 24.2 (part by Zinc oxide 5 5
5 5 5 5 5 weight) Barium sulfate 16.2 16.7 18.8 18.2 4.8 18.0 23.3
Dicumyl peroxide 1.4 1.4 1.4 1.4 1.4 1.4 1.4 Physical Hardness of
Core 4.5 4.8 5.5 5.5 4.5 3.5 4.2 Properties (deformed amount under
980N) of Core Composition Himilan 1605 50 50 50 of Cover Himilan
1706 50 (part by Himilan AM7317 50 50 weight) Himilan AM7318 50 50
Himilan AM7315 50 100 100 50 Barium sulfate 10 10 10 10 40 Titanium
dioxide 4 4 4 4 4 4 4 Physical Hardness of Cover (Shore D) 69 68 69
69 67 64 67 Properties Base resin (with no additive) 67 66 67 67 64
64 67 of Cover Thickness (mm) of Cover 1.9 1.9 1.9 1.9 1.9 1.9 2.5
Data of Weight (g) of Core 45.3 45.3 45.3 45.3 45.3 45.3 45.3 Ball
Outer diameter (mm) of Cover 42.7 42.7 42.7 42.7 42.7 42.7 42.7
Carry Hitting angle (.degree.) 12.2 12.3 12.7 12.6 12.0 11.8 12.0
HS40 Spin (rpm) 2680 2600 2370 2450 2720 2960 2710 Total carry (m)
196.3 196.3 196.3 196.3 192.3 195.7 193.0 Durability against
Continuous Hitting .circleincircle. .circleincircle.
.circleincircle. .circleincircle. .circleincircle. X X Felling of
Hitting Soft Very Very Very Soft Hard Soft soft soft soft
[0046] Measurement of Carry:
[0047] The ball was hit with a hitting machine (sold by Miyamae
Co., Ltd.), to which a driver with a loft angle of 10.degree. (sold
by Bridgestone Sports Co., Ltd.) was mounted, and the carry of the
ball was measured.
[0048] Durability Against Continuous Hitting:
[0049] The durability against continuous hitting, which was
performed by a rotary drum type continuous hitting machine, was
evaluated.
[0050] .circleincircle.: very good
[0051] .largecircle.: good
[0052] .times.: undesirable
[0053] Feeling of Hitting:
[0054] The feeling of hitting of the golf ball was evaluated by a
function test performed by 10 of professional players and 10 of
amateur players.
[0055] As is apparent from Table 1, the golf ball in Examples 1 to
4 is superior to the golf ball in Comparative Example 1 to 3 in
terms of carrying performance, durability against continuous
hitting, and feeling of hitting.
[0056] While the present invention has been described using
specific terms, such description is for illustrative purposes only,
and it is understood that changes and variations may be made
without departing from the spirit of scope of the following
claims.
* * * * *