U.S. patent application number 17/547902 was filed with the patent office on 2022-06-23 for golf ball.
This patent application is currently assigned to Sumitomo Rubber Industries, Ltd.. The applicant listed for this patent is Sumitomo Rubber Industries, Ltd.. Invention is credited to Hidetaka INOUE, Takashi KAJIKAWA.
Application Number | 20220193503 17/547902 |
Document ID | / |
Family ID | 1000006066848 |
Filed Date | 2022-06-23 |
United States Patent
Application |
20220193503 |
Kind Code |
A1 |
KAJIKAWA; Takashi ; et
al. |
June 23, 2022 |
GOLF BALL
Abstract
An object of the present invention is to provide a golf ball
having high visibility and little uncomfortableness at shot. The
present invention provides a golf ball comprising a core and a
cover disposed outside of the core, wherein a surface of the golf
ball has a first region with a first color and a second region with
a second color, the first color has hue H1 represented by H value
in HSL color space, the second color has hue H2 represented by H
value in HSL color space, and the H1 and the H2 satisfy a specific
mathematical formula.
Inventors: |
KAJIKAWA; Takashi;
(Kobe-shi, JP) ; INOUE; Hidetaka; (Kobe-shi,
JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Sumitomo Rubber Industries, Ltd. |
Kobe-shi |
|
JP |
|
|
Assignee: |
Sumitomo Rubber Industries,
Ltd.
Kobe-shi
JP
|
Family ID: |
1000006066848 |
Appl. No.: |
17/547902 |
Filed: |
December 10, 2021 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A63B 37/00223 20200801;
A63B 37/00373 20200801; A63B 37/00221 20200801 |
International
Class: |
A63B 37/00 20060101
A63B037/00 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 23, 2020 |
JP |
2020-214235 |
Claims
1. A golf ball comprising a core and a cover disposed outside of
the core, wherein a surface of the golf ball has a first region
with a first color and a second region with a second color, the
first color has hue H1 represented by H value in HSL color space,
the second color has hue H2 represented by H value in HSL color
space, and the H1 and the H2 satisfy the following mathematical
formula (1) or mathematical formula (2): 0.ltoreq.|H1-H2|.ltoreq.60
(1) 300.ltoreq.|H1-H2|.ltoreq.360 (2).
2. The golf ball according to claim 1, wherein the golf ball
further comprises at least one intermediate layer between the core
and the cover, an outermost layer of the intermediate layer has hue
H0 represented by H value in HSL color space, and either one of
|H0-H1| and |H0-H2| is less than 10, and the other one of |H0-H1|
and |H0-H2| is 10 or more.
3. The golf ball according to claim 1, wherein the first color of
the first region has saturation S1 represented by S value in HSL
color space, the first color of the first region has lightness L1
represented by L value in HSL color space, and the S1 is 40 or more
and 100 or less, and the L1 is 30 or more and 100 or less.
4. The golf ball according to claim 1, wherein the second color of
the second region has saturation S2 represented by S value in HSL
color space, the second color of the second region has lightness L2
represented by L value in HSL color space, and the S2 is 40 or more
and 100 or less, and the L2 is 30 or more and 100 or less.
5. The golf ball according to claim 1, wherein the first region and
the second region are each a region surrounded by two boundary
lines connecting a first pole and a second pole of the golf ball
surface wherein the region continues from the first pole to the
second pole.
6. The golf ball according to claim 1, wherein the first region and
the second region are each hemispherical.
7. The golf ball according to claim 1, wherein the golf ball
further comprises a paint film covering the cover, and the paint
film contains a resin component and a filler.
8. The golf ball according to claim 1, wherein the golf ball
further comprises a paint film covering the cover, and the paint
film is a clear paint film.
9. The golf ball according to claim 1, wherein the first region and
the second region are each formed by a colored cover.
10. The golf ball according to claim 1, wherein the first region
and the second region are each formed by a colored paint film.
11. The golf ball according to claim 1, wherein either one of the
first region and the second region is formed by a colored cover,
and the other one of the first region and the second region is
formed by a colored paint film.
12. The golf ball according to claim 1, wherein the hue H1 of the
first color of the first region ranges from 20 to 340.
13. The golf ball according to claim 1, wherein the hue H2 of the
second color of the second region ranges from 0 to 360.
14. The golf ball according to claim 2, wherein the hue H0 of the
outermost layer of the intermediate layer ranges from 0 to 360.
15. The golf ball according to claim 2, wherein the outermost layer
of the intermediate layer has saturation S0 represented by S value
in HSL color space, and the saturation S0 ranges from 30 to
100.
16. The golf ball according to claim 2, wherein the outermost layer
of the intermediate layer has lightness L0 represented by L value
in HSL color space, and the lightness L0 ranges from 30 to 100.
17. The golf ball according to claim 7, wherein an amount of the
filler ranges from 3 parts by mass to 200 parts by mass with
respect to 100 parts by mass of the resin component.
18. The golf ball according to claim 1, wherein an area ratio of
the first region to the second region ranges from 20/80 to 80/20.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to a golf ball, and
particularly relates to a colored golf ball.
DESCRIPTION OF THE RELATED ART
[0002] Conventionally, a golf ball is white. In case of bad weather
conditions such as rainy, cloudy, foggy and dim conditions, it is
difficult to follow the trajectory of the white golf ball and
visually recognize where the golf ball falls. In addition, in a
case that the white golf ball lies on dead grass, it is difficult
to find the golf ball even if the golf ball is nearby. In addition,
recently, golf players desiring a fashionable golf ball are also
increasing. Under such circumstances, a colored golf ball has been
proposed in order to satisfy the requirements such as the
fashionable appearance and the visibility under bad weather
conditions.
[0003] JP S63-38476 A discloses a method for producing a golf ball,
comprising covering a first hemispherical shell and a core charged
into a hemispherical concave portion of a lower mold having the
hemispherical concave portion with a second hemispherical shell
with a different color from the first hemispherical shell to form a
sphere, covering an upper mold on the sphere, and heating and
pressing the same to form a colored golf ball with two tones,
wherein a protrusion for being horizontally locked to an edge of
the concave portion of the lower mold is formed in the vicinity of
an edge face of an opening of the first hemispherical shell.
[0004] JP 2013-183833 A discloses a golf ball comprising a core and
a cover, wherein the cover consists of a first hemisphere and a
second hemisphere, and the first hemisphere has a different style
from the second hemisphere. JP 2013-183833 A further discloses the
first hemisphere is formed from a first resin composition, the
second hemisphere is formed from a second resin composition, and
the first resin composition may have a different composition from
the second resin composition.
[0005] JP 2017-118950 A discloses a golf ball comprising a core
composed of at least one layer and a cover composed of at least one
layer, wherein an outermost layer of the core has two hemispheres
with color tones different from each other and formed from a rubber
composition, a boundary between the hemispheres as a colored
boundary line is formed along a great circle of the outermost layer
of the core, at least one of the hemispheres contains a fluorescent
coloring agent or a luminous agent, the cover is formed from a
transparent or translucent thermoplastic resin composition, and at
least one layer of the cover contains at least one of a fluorescent
brightener, a fluorescent coloring agent, and a luminous agent.
[0006] JP S59-64165 U discloses a golf ball having a shell layer
formed by covering a surface of a core with a plurality of shells
with different colors, wherein an outer surface of the golf ball is
comparted by the difference in the color of the shell layer.
[0007] U.S. Pat. No. 7,862,760 discloses a golf ball comprising a
multi-color layer obtained by injection molding a first material
and a second material respectively.
[0008] U.S. Pat. No. 8,915,802 discloses a golf ball comprising at
least two layers, wherein each layer has at least two different
color regions by which the golf ball shows an overall multi-color
appearance.
[0009] U.S. Pat. No. 9,067,105 discloses a golf ball comprising a
first hemispherical cover and a second hemispherical cover having a
color tone different from each other.
SUMMARY OF THE INVENTION
[0010] An object of the present invention is to provide a golf ball
having high visibility and little uncomfortableness at shot.
[0011] The present invention that has solved the above problem
provides a golf ball comprising a core and a cover disposed outside
of the core, wherein a surface of the golf ball has a first region
with a first color and a second region with a second color, the
first color has hue H1 represented by H value in HSL color space,
the second color has hue H2 represented by H value in HSL color
space, and the H1 and the H2 satisfy the following mathematical
formula (1) or mathematical formula (2):
0.ltoreq.|H1-H2|.ltoreq.60 (1)
300.ltoreq.|H1-H2|.ltoreq.360 (2).
[0012] If the relationship of the mathematical formula (1) or the
mathematical formula (2) is satisfied, the first color of the first
region and the second color of the second region are similar color.
As a result, the golf ball has little uncomfortableness at shot and
is easily found on the rough.
[0013] According to the present invention, a golf ball having high
visibility and little uncomfortableness at shot is obtained.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] FIG. 1 is a front view illustrating a golf ball according to
one embodiment of the present invention;
[0015] FIG. 2 is a plan view illustrating a golf ball according to
one embodiment of the present invention;
[0016] FIG. 3 is a front view illustrating a golf ball according to
one embodiment of the present invention;
[0017] FIG. 4 is a plan view illustrating a golf ball according to
one embodiment of the present invention; and
[0018] FIG. 5 is a partially cutaway cross-sectional view of a golf
ball according to one embodiment of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0019] The present invention provides a golf ball comprising a core
and a cover disposed outside of the core, wherein a surface of the
golf ball has a first region with a first color and a second region
with a second color, the first color has hue H1 represented by H
value in HSL color space, the second color has hue H2 represented
by H value in HSL color space, and the H1 and the H2 satisfy the
following mathematical formula (1) or mathematical formula (2):
0.ltoreq.|H1-H2|.ltoreq.60 (1)
300.ltoreq.|H1-H2|.ltoreq.360 (2).
[0020] The surface of the golf ball according to the present
invention has a first region with a first color, and a second
region with a second color which is different from the first color.
The first region and the second region are each preferably a region
with a single color.
[0021] The first color of the first region has hue H1 represented
by H value in HSL color space, the second color of the second
region has hue H2 represented by H value in HSL color space, and
the H1 and the H2 satisfy the following mathematical formula (1) or
mathematical formula (2):
0.ltoreq.|H1-H2|.ltoreq.60 (1)
300.ltoreq.|H1-H2|.ltoreq.360 (2).
[0022] It is noted that, in the present invention, "the hue of the
first color of the first region" is sometimes simply referred to as
"the hue of the first region", and "the hue of the second color of
the second region" is sometimes simply referred to as "the hue of
the second region".
[0023] When the hue H1 of the first region and the hue H2 of the
second region satisfy the mathematical formula (1), an absolute
value |H1-H2| of a difference between the hue H1 of the first
region and the hue H2 of the second region is preferably 0 or more,
more preferably more than 0, even more preferably 5 or more, and
most preferably 7 or more, and is preferably 60 or less, more
preferably 55 or less, and even more preferably 50 or less. If the
absolute value |H1-H2| falls within the above range, an effect of
enhancing the visibility and eliminating the uncomfortableness at
shot can be obtained.
[0024] When the hue H1 of the first region and the hue H2 of the
second region satisfy the mathematical formula (2), an absolute
value |H1-H2| of a difference between the hue H1 of the first
region and the hue H2 of the second region is preferably 300 or
more, more preferably 305 or more, and even more preferably 307 or
more, and is preferably 360 or less, more preferably 355 or less,
and even more preferably 350 or less. If the absolute value |H1-H2|
falls within the above range, an effect of enhancing the visibility
and eliminating the uncomfortableness at shot can be obtained.
[0025] The hue H1 of the first color of the first region is H value
in HSL color space. The H1 is preferably 20 or more, more
preferably 30 or more, and even more preferably 40 or more, and is
preferably 340 or less, more preferably 330 or less, and even more
preferably 320 or less.
[0026] The saturation S1 of the first color of the first region is
S value in HSL color space. The S1 is preferably 40 or more, more
preferably 45 or more, and even more preferably 50 or more, and is
preferably 100 or less, more preferably 95 or less, and even more
preferably 90 or less.
[0027] The lightness L1 of the first color of the first region is L
value in HSL color space. The L1 is preferably 30 or more, more
preferably 40 or more, and even more preferably 50 or more, and is
preferably 100 or less, more preferably 90 or less, and even more
preferably 80 or less.
[0028] The hue H2 of the second color of the second region is H
value in HSL color space value. The H2 is preferably 0 or more,
more preferably 5 or more, and even more preferably 10 or more, and
is preferably 360 or less, more preferably 350 or less.
[0029] The saturation S2 of the second color of the second region
is S value in HSL color space value. The S2 is preferably 40 or
more, more preferably 50 or more, and even more preferably 60 or
more, and is preferably 100 or less, more preferably 90 or less,
and even more preferably 80 or less.
[0030] The lightness L2 of the second color of the second region is
L value in HSL color space. The L2 is preferably 30 or more, more
preferably 40 or more, and even more preferably 50 or more, and is
preferably 100 or less, more preferably 90 or less, and even more
preferably 80 or less.
[0031] The first color of the first region is not particularly
limited, but the first color is preferably a color selected from
the group consisting of white, yellow, orange, blue, red, pink,
green and black. The second color of the second region is not
particularly limited, as long as the second color is a color
different from the first color of the first region, but the second
color is preferably a color selected from the group consisting of
white, yellow, orange, blue, red, pink, green and black.
[0032] The area of the first region on the golf ball surface is
preferably 10% or more, more preferably 20% or more, and even more
preferably 30% or more, and is preferably 90% or less, more
preferably 80% or less, and even more preferably 70% or less, of
the golf ball surface area.
[0033] The area of the second region on the golf ball surface is
preferably 10% or more, more preferably 20% or more, and even more
preferably 30% or more, and is preferably 90% or less, more
preferably 80% or less, and even more preferably 70% or less, of
the golf ball surface area.
[0034] The area ratio of the first region to the second region is
not particularly limited, but the area ratio is preferably 20/80 or
more, more preferably 30/70 or more, and even more preferably 50/50
or more, and is preferably 80/20 or less, more preferably 70/30 or
less.
[0035] The shape of the first region and the second region is not
particularly limited, and examples thereof include a polygonal
shape such as a triangular shape, quadrangular shape, pentagonal
shape and hexagonal shape; a trapezoidal shape; a circle shape; and
an elliptical shape, in a plan view. It is noted that a string of
letters such as a trade name and a ball number usually formed on
the golf ball surface is not qualified as the first region and the
second region in the present invention.
[0036] The first region and the second region may be each formed
only at one spot of the golf ball surface, or at a plurality of
spots of the golf ball surface.
[0037] In the present invention, in the case that the golf ball
surface consists of the first region and the second region, for
example, when the first region has a specific shape, the second
region is a region other than the first region. For example, if the
first region has a polygonal shape such as a triangular shape,
quadrangular shape, pentagonal shape and hexagonal shape, a
trapezoidal shape, a circle shape, or an elliptical shape in a plan
view, the second region is a region on the golf ball surface other
the first region.
[0038] In addition, in a preferable embodiment according to the
present invention, the first region and the second region are each
a region surrounded by two boundary lines connecting the first pole
and the second pole of the golf ball surface wherein the region
continues from the first pole to the second pole. Herein, the first
pole and the second pole are each an intersection point of the golf
ball surface with the central axis passing through the center point
of the golf ball. The first region and the second region are each
preferably hemispherical.
[0039] FIG. 1 is an illustrative figure illustrating a preferable
embodiment of the first region and the second region of the present
invention. The golf ball 1 has a first pole P1 and a second pole P2
where the axis passing through the center point of the golf ball
intersects with the golf ball surface. FIG. 1 is a front view in
which the first pole P1 and the second pole P2 are disposed in the
up-down direction, and the first region S1 is disposed at the
front. FIG. 2 is a plan view observed from the first pole P1. The
first region S1 and the second region S2 are each a region
surrounded by two boundary lines L1 and L2 connecting the first
pole P1 and the second pole P2 of the golf ball surface wherein the
region continues from the first pole to the second pole. In the
embodiment of FIG. 1 and FIG. 2, the first region S1 is a region
occupying one third of the golf ball surface, and the second region
S2 is a region occupying two third of the golf ball surface.
[0040] FIG. 3 is an illustrative figure illustrating another
preferable embodiment of the first region and the second region of
the present invention. FIG. 3 is a front view in which the first
pole P1 and the second pole P2 are disposed in the up-down
direction, and the boundary line L1 between the first region S1 and
the second region S2 is disposed at the front. FIG. 4 is a plan
view observed from the first pole P1. The above golf ball surface
consists of the first region S1 and the second region S2, and the
first region S1 and the second region S2 are each
hemispherical.
[0041] The first region and the second region may be each formed by
the colored paint film, or may be each formed by the colored cover.
Examples thereof include an embodiment that the first region and
the second region are formed by the colored cover; an embodiment
that the first region and the second region are formed by the
colored paint film; and an embodiment that either one of the first
region and the second region is formed by the colored cover, and
the other one of the first region and the second region is formed
by the colored paint film.
[0042] The golf ball according to the present invention may further
have at least one intermediate layer between the core and the
cover. The outermost layer of the intermediate layer has hue H0
represented by H value in HSL color space. Either one of |H0-H1|
and |H0-H2| is preferably less than 10, and the other one of
|H0-H1| and |H0-H2| is preferably 10 or more. In a case that the
intermediate layer has a plurality of layers, the outermost layer
is the layer of the intermediate layer closest to the cover. In a
case that the intermediate layer is single layered, the outermost
layer is the single layered intermediate layer.
[0043] Either one of |H0-H1| and |H0-H2| is preferably less than
10, more preferably 7 or less, and even more preferably 4 or less.
If either one of |H0-H1| and |H0-H2| is less than 10, the golf ball
has an appearance with better color development and inconspicuous
dimple contour.
[0044] The other one of |H0-H1| and |H0-H2| is preferably 10 or
more, more preferably 20 or more, and even more preferably 30 or
more, and is preferably 85 or less, more preferably 75 or less, and
even more preferably 65 or less. If the other one of |H0-H1| and
|H0-H2| is 10 or more, the first region and the second region are
more distinguishable while keeping the color development.
[0045] The hue H0 of the outermost layer of the intermediate layer
is H value in HSL color space. The H0 is preferably 0 or more, more
preferably 10 or more, and even more preferably 20 or more, and is
preferably 360 or less, more preferably 350 or less, and even more
preferably 340 or less.
[0046] The saturation S0 of the outermost layer of the intermediate
layer is S value in HSL color space. The S0 is preferably 30 or
more, more preferably 40 or more, and even more preferably 50 or
more, and is preferably 100 or less, more preferably 97 or less,
and even more preferably 94 or less.
[0047] The lightness L0 of the outermost layer of the intermediate
layer is L value in HSL color space. The L0 is preferably 30 or
more, more preferably 40 or more, and even more preferably 50 or
more, and is preferably 100 or less, more preferably 97 or less,
and even more preferably 94 or less.
[0048] In the present invention, the color of the golf ball surface
and the outermost layer of the intermediate layer can be determined
by L* value, a* value and b* value in CIELAB color coordinate
system. L* value, a* value and b* value in CIELAB color coordinate
system can be measured according to JIS-Z-8701 or JIS-Z-8728. In
the measurement, suitably used is a color difference meter CM-350d
available from Minolta Co., in which a tristimulus values direct
measuring method is adopted. Tristimulus values X, Y and Z are
converted into L*, a* and b* as follows.
L*=116(Y/YN).sup.1/3-16
a*=500[(X/XN).sup.1/3-(Y/YN).sup.1/3]
b*=200[(Y/YN).sup.1/3-(Z/ZN).sup.1/3]
[0049] XN, YN and ZN are tristimulus values in the XYZ coordinate
system of a perfect diffuse reflection surface.
[0050] In the present invention, the L* value, a* value and b*
value obtained as above are converted into the H value (hue), S
value (saturation) and L value (lightness) in HSL color space by
using a color code conversion tool. As the color code conversion
tool, for example, the tool described at the following website can
be used.
[0051] https://syncer.jp/color-converter
[Golf Ball Material]
[0052] The golf ball according to the present invention comprises a
core, at least one intermediate layer covering the core, and a
cover covering the intermediate layer. Next, materials constituting
each constituent element of the golf ball will be explained.
[Intermediate Layer and Cover]
[0053] The intermediate layer and/or cover of the golf ball
according to the present invention is formed from a composition
containing a resin component. It is noted that in the present
invention, the resin composition for forming the intermediate layer
is sometimes referred to as the intermediate layer composition, and
the resin composition for forming the cover is sometimes referred
to as the cover composition. Examples of the resin component
include an ionomer resin, a thermoplastic polyurethane elastomer
having a trade name of "Elastollan (registered trademark)"
available from BASF Japan Ltd., a thermoplastic polyamide elastomer
having a trade name of "Pebax (registered trademark)" available
from Arkema K. K., a thermoplastic polyester elastomer having a
trade name of "Hytrel (registered trademark)" available from Du
Pont-Toray Co. Ltd., and a thermoplastic styrene elastomer having a
trade name of "TEFABLOC (registered trademark)" available from
Mitsubishi Chemical Corporation.
[0054] Examples of the ionomer resin include a product obtained by
neutralizing at least a part of carboxyl groups of a binary
copolymer composed of an olefin and an .alpha.,.beta.-unsaturated
carboxylic acid having 3 to 8 carbon atoms with a metal ion; a
product obtained by neutralizing at least a part of carboxyl groups
of a ternary copolymer composed of an olefin, an
.alpha.,.beta.-unsaturated carboxylic acid having 3 to 8 carbon
atoms and an .alpha.,.beta.-unsaturated carboxylic acid ester with
a metal ion; and a mixture thereof. The olefin is preferably an
olefin having 2 to 8 carbon atoms. Examples of the olefin include
ethylene, propylene, butene, pentene, hexene, heptene and octene,
and ethylene is particularly preferable. Examples of the
.alpha.,.beta.-unsaturated carboxylic acid having 3 to 8 carbon
atoms include acrylic acid, methacrylic acid, fumaric acid, maleic
acid and crotonic acid, and acrylic acid or methacrylic acid is
particularly preferable. In addition, as the
.alpha.,.beta.-unsaturated carboxylic acid ester, methyl ester,
ethyl ester, propyl ester, n-butyl ester, isobutyl ester or the
like of acrylic acid, methacrylic acid, fumaric acid, maleic acid
or the like can be used, and acrylic acid ester or methacrylic acid
ester is particularly preferable. Among them, as the ionomer resin,
a metal ion-neutralized product of an ethylene-(meth)acrylic acid
binary copolymer, or a metal ion-neutralized product of an
ethylene-(meth)acrylic acid-(meth)acrylic acid ester ternary
copolymer is preferable.
[0055] The resin composition constituting the intermediate layer or
cover of the golf ball according to the present invention
preferably contains the thermoplastic polyurethane elastomer or
ionomer resin as the resin component. In case of using the ionomer
resin, the thermoplastic styrene elastomer is also preferably used
in combination. The amount of the polyurethane or ionomer resin in
the resin component of the resin composition is preferably 50 mass
% or more, more preferably 60 mass % or more, and even more
preferably 70 mass % or more.
[0056] In a preferable embodiment according to the present
invention, the intermediate layer is formed from a composition
containing the ionomer resin, and the cover is formed from a
composition containing the thermoplastic urethane elastomer.
[Dye and/or Pigment]
[0057] The intermediate layer and/or cover of the golf ball
according to the present invention preferably contains a dye and/or
a pigment, more preferably contains a fluorescent dye and/or a
fluorescent pigment. The fluorescent dye may be organic or
inorganic, and may be any commercially available fluorescent dye.
Examples of the fluorescent dye include a thioxanthene derivative,
a xanthene derivative, a perylene derivative, a perylene imide
derivative, a coumarin derivative, a thioindigo derivative, a
naphthalimide derivative, and a methine derivative.
[0058] In a preferable embodiment, the melting point of the
fluorescent dye and/or fluorescent pigment is preferably
180.degree. C. or less, more preferably 175.degree. C. or less, and
even more preferably 170.degree. C. or less, and is preferably
135.degree. C. or more, more preferably 140.degree. C. or more, and
even more preferably 145.degree. C. or more. If the melting point
of the fluorescent dye and/or fluorescent pigment falls within the
above range, mixing and dispersing the fluorescent dye and/or
fluorescent pigment in the resin component can be conducted at a
relatively low temperature. Since the color change due to a high
temperature during processing is not likely to occur, the desired
color tone can be easily obtained.
[0059] The fluorescent dye is not particularly limited, and
specific examples thereof include a yellow fluorescent dye such as
Lumogen F Orange.TM. 240 (available from BASF Ltd.); Lumogen F
Yellow.TM. 083 (available from BASF Ltd.); Hostasol Yellow.TM. 3G
(available from Hoechst-Celanese Corp.); Oraset Yellow.TM. 8GF
(available from Ciba-Geigy Ltd.); Fluorol 088.TM. (available from
BASF Ltd.); Thermoplast F Yellow.TM. 084 (available from BASF
Ltd.); Golden Yellow.TM. D-304 (available from DayGlo Color Corp.);
Mohawk Yellow.TM. D-299 (available from DayGlo Color Corp.);
Potomac Yellow.TM. D-838 (available from DayGlo Color Corp.); and
Polyfast Brilliant Red.TM. SB (available from Keystone Corp.).
[0060] Examples of the fluorescent pigment include a pigment having
a fluorescent dye dispersed in a polymer material, and a pigment
having a fluorescent dye formed into a particle shape. The
fluorescent pigment is not particularly limited, and examples
thereof include ZQ-11, ZQ-12, ZQ-13, ZQ-14, ZQ-15, ZQ-16, ZQ-17-N,
ZQ-18, ZQ-19, ZQ-21, GPL-11, GPL-13, GPX-14, GPL-15, GPX-17, GPL-19
and GPL-21 available from DayGlo Color Corp., and FZ-2000 series,
FZ-5000 series, FZ-6000 series, FZ-3040 series and FX-300 series
available from Sinloihi Co., Ltd.
[0061] Examples of the polymer material in which the fluorescent
dye is dispersed include a benzoguanamine resin, an acrylic resin,
and a polyester resin.
[0062] In a preferable embodiment, the amount of the dye and/or
pigment contained in the cover and at least one layer of the
intermediate layer is preferably 0.5 part by mass or more, more
preferably 0.6 part by mass or more, and even more preferably 0.7
part by mass or more, and is preferably 7 parts by mass or less,
more preferably 6 parts by mass or less, even more preferably 5
parts by mass or less, and most preferably 4 parts by mass or less,
with respect to 100 parts by mass of the resin component. If the
amount is too large, the color of the golf ball is so deep that the
golf ball has a dark color tone, and if the amount is too small,
the desired color tone is not obtained.
[0063] Since the fluorescent dye and/or fluorescent pigment has low
light stability, an ultraviolet absorber or light stabilizer is
preferably used. The ultraviolet absorber or light stabilizer is
not particularly limited, and may be any commercially available
product. Examples of the ultraviolet absorber or light stabilizer
include an ultraviolet absorber such as a salicylic acid
derivative, a benzophenone derivative, a benzotriazole derivative,
a cyanoacrylate derivative, a triazine derivative and a nickel
complex; and a light stabilizer such as a hindered amine
derivative.
[0064] Examples of the salicylic acid derivative ultraviolet
absorber include phenyl salicylate, p-t-butylphenyl salicylate, and
p-octylphenyl salicylate. Examples of the benzophenone derivative
ultraviolet absorber include 2,4-dihydroxybenzophenone,
2-hydroxy-4-methoxybenzophenone, and
2-hydroxy-4-octyloxybenzophenone,
2,2-dihydroxy-4,4'-methoxybenzophenone. Examples of the
benzotriazole derivative ultraviolet absorber include
2-(2'-hydroxy-5'-methylphenyl)benzotriazole,
2-(2'-hydroxy-5'-t-butylphenyl)benzotriazole,
2-(2'-hydroxy-3'-t-butyl-5'-methylphenyl)-5-chlorobenzotriazole,
2-[2-hydroxy-3,5-bis(.alpha.,.alpha.'-dimethylbenzyl)phenyl]-2H-benzotria-
zole, and 2-(5-methyl-2-hydroxyphenyl)benzotriazole. Examples of
the cyanoacrylate derivative ultraviolet absorber include
2-ethylhexyl-2-cyano-3,3'-diphenylacrylate, and
ethyl-2-cyano-3,3'-diphenylacrylate. Examples of the triazine
derivative ultraviolet absorber include
2-(4,6-diphenyl-1,3,5-triazine-2-yl)-5[(hexyl)oxy]-phenol,
2,4-bis(2-hydroxy-4-butyloxyphenyl)-6-(2,4-bis-butyloxyphenyl)-1,3,5-tria-
zine, and
2-(4-{[2-hydroxy-3-(2'-ethyl)hexyl]oxy}-2-hydroxyphenyl)-4,6-bis-
(2,4-dimethylphenyl)-1,3,5-triazine. Specific examples include
"Sumisoap 130" and "Sumisoap 140" (both of which are
benzophenone-based ultraviolet absorber) available from Sumitomo
Chemical Co., Ltd.; "TINUVIN 234", "TINUVIN 900", "TINUVIN 326" and
"TINUVIN P" (all of which are benzotriazole-based ultraviolet
absorber) available from Ciba Specialty Chemicals plc.; "Uvinul
N-35" (cyanoacrylate-based ultraviolet absorber) available from
BASF Ltd.; and "TINUVIN 1577", "TINUVIN 460" and "TINUVIN 405"
(triazine-based ultraviolet absorber) available from Ciba Specialty
Chemicals plc. These ultraviolet absorbers may be used solely, or
two or more of them may be used in combination. It is noted that
the ultraviolet absorber that can be used in the present invention
is not limited to the above examples, and any conventional
ultraviolet absorber can be used.
[0065] Examples of the light stabilizer such as the hindered amine
derivative include
bis(1,2,2,6,6-pentamethyl-4-piperidyl){[3,5-bis(1,1'-dimethylethyl)-4-hyd-
roxyphenyl]methyl}butyl malonate, and
1-{2-[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionyloxy]ethyl}-4-[3-(3,5-di--
t-butyl-4-hydroxyphenyl)propionyloxy]-2,2,6,6-tetramethylpiperidine.
Specific examples include "Sanol LS-2626" and "TINUVIN 144"
available from Ciba Specialty Chemicals plc.
[0066] The amount of the ultraviolet absorber or light stabilizer
is preferably 0.02 part by mass or more, more preferably 0.04 part
by mass or more, and is preferably 2 parts by mass or less, more
preferably 1 part by mass or less, with respect to 100 parts by
mass of the resin component of the intermediate layer or cover. If
the amount of the ultraviolet absorber or light stabilizer falls
within the above range, the color change due to the exposure to
sunlight can be effectively suppressed.
(Titanium Oxide)
[0067] The intermediate layer and/or cover may contain titanium
oxide. The combination of the fluorescent pigment with a small
amount of titanium oxide can provide a translucent cover with a
vivid color. Since titanium oxide provides high opacity, the amount
of titanium oxide is preferably 0.001 part by mass or more, more
preferably 0.002 part by mass or more, and even more preferably
0.005 part by mass or more, and is preferably 0.7 part by mass or
less, more preferably 0.5 part by mass or less, and even more
preferably 0.4 part by mass or less, with respect to 100 parts by
mass of the resin component. If the amount of titanium oxide is
0.001 part by mass or more, a translucent cover with a vivid color
is obtained, and if the amount of titanium oxide is more than 0.7
part by mass, the cover tends to be opaque.
[0068] In case of increasing the opacity of the intermediate layer
and/or cover and increasing the degree of the white color, the
amount of titanium oxide can be increased. In this case, the amount
of titanium oxide is preferably more than 0.7 part by mass, more
preferably 1 part by mass or more, and is preferably 10 parts by
mass or less, more preferably 8 parts by mass or less, with respect
to 100 parts by mass of the resin component constituting the
intermediate layer and/or the cover. If the amount of titanium
oxide is more than 0.7 part by mass, the intermediate layer and/or
cover has enhanced opacity. In addition, if the amount of titanium
oxide is more than 10 parts by mass, the obtained intermediate
layer and/or cover may have lowered durability.
(Other Component)
[0069] In addition to the above described components, the
intermediate layer and/or cover may contain a mass adjusting agent
such as zinc oxide, calcium carbonate and barium sulfate, a
dispersant, an antioxidant, a fluorescent brightener, a lubricant,
a light stabilizer, or the like, as long as they do not impair the
performance of the intermediate layer and/or cover.
[0070] The golf ball according to the present invention preferably
has a paint film covering the cover. In the case that the golf ball
according to the present invention has the paint film, the color of
the golf ball surface can be obtained by measuring the surface of
the paint film formed on the golf ball surface. Examples of the
paint film include a clear paint film that is colorless and
transparent, a nontransparent colored paint film, and a matte paint
film.
[0071] In the case that the golf ball has a clear paint film that
is colorless and transparent, the first color of the first region
and the second color of the second region on the golf ball surface
reflect the color of the cover. In the case that the golf ball has
a nontransparent colored paint film or a matte paint film, the
color tone of the golf ball surface is affected by the paint
film.
[0072] The nontransparent colored paint film preferably contains,
for example, a resin component and the dye and/or pigment. The
matte paint film preferably contains, for example, a resin
component and a filler.
[0073] The resin component constituting the paint film is not
particularly limited, an acrylic resin, epoxy resin, polyurethane,
polyester, cellulose-based resin or the like can be used, and a
two-component curing type polyurethane which will be described
later is preferably used. If the two-component curing type
polyurethane is used, the obtained paint film has further enhanced
durability.
(Polyurethane)
[0074] The polyurethane is preferably a polyurethane (two-component
curing type polyurethane) obtained by a reaction between a polyol
composition and a polyisocyanate composition.
(Polyol Composition)
[0075] The polyol composition contains a polyol compound. Examples
of the polyol compound include a compound having at least two
hydroxy groups in the molecule. Examples of the polyol compound
include a compound having a hydroxy group at a terminal of the
molecule, and a compound having a hydroxy group at a position other
than the terminal of the molecule. The polyol compound may be used
solely, or two or more of the polyol compounds may be used in
combination.
[0076] Examples of the compound having the hydroxy group at the
terminal of the molecule include a low molecular weight polyol
having a molecular weight of less than 500, and a high molecular
weight polyol having a number average molecular weight of 500 or
more. Examples of the low molecular weight polyol include a diol
such as ethylene glycol, diethylene glycol, triethylene glycol,
1,3-butanediol, 1,4-butanediol, neopentyl glycol, and
1,6-hexanediol, and a triol such as glycerin, trimethylolpropane,
and hexanetriol. Examples of the high molecular weight polyol
include a polyether polyol, a polyester polyol, a polycaprolactone
polyol, a polycarbonate polyol, an urethane polyol, and an acrylic
polyol. Examples of the polyether polyol include polyoxyethylene
glycol (PEG), polyoxypropylene glycol (PPG), and
polyoxytetramethylene glycol (PTMG). Examples of the polyester
polyol include polyethylene adipate (PEA), polybutylene adipate
(PBA), and polyhexamethylene adipate (PHMA). Examples of the
polycaprolactone polyol include poly-.epsilon.-caprolactone (PCL).
Examples of the polycarbonate polyol include polyhexamethylene
carbonate.
[0077] The polyol composition preferably contains a urethane polyol
as the polyol component. The urethane polyol is synthesized by a
reaction between a polyisocyanate and a polyol. The polyisocyanate
for use in synthesis of the urethane polyol is not particularly
limited, as long as the polyisocyanate has at least two isocyanate
groups, and examples thereof include an aromatic polyisocyanate
such as 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, a
mixture of 2,4-toluene diisocyanate and 2,6-toluene diisocyanate
(TDI), 4,4'-diphenylmethane diisocyanate (MDI), 1,5-naphthylene
diisocyanate (NDI), 3,3'-bitolylene-4,4'-diisocyanate (TODD,
xylylene diisocyanate (XDI), tetramethylxylylenediisocyanate
(TMXDI), and para-phenylene diisocyanate (PPDI); and an alicyclic
polyisocyanate or aliphatic polyisocyanate such as
4,4'-dicyclohexylmethane diisocyanate (H.sub.12MDI), hydrogenated
xylylenediisocyanate (H6XDI), hexamethylene diisocyanate (HDI),
isophorone diisocyanate (IPDI), and norbornene diisocyanate (NBDI).
These polyisocyanates may be used solely or as a mixture of at
least two of them. Among them, from the viewpoint of weather
resistance, the non-yellowing type polyisocyanate (TMXDI, XDI, HDI,
H.sub.6XDI, IPDI, H.sub.12MDI, NBDI, etc) is preferably used.
[0078] The polyol for use in synthesis of the urethane polyol is
not particularly limited, as long as the polyol has a plurality of
hydroxy groups, and examples thereof include a low molecular weight
polyol and a high molecular weight polyol. Examples of the low
molecular weight polyol include a diol such as ethylene glycol,
diethylene glycol, triethylene glycol, 1,3-butanediol,
1,4-butanediol, neopentyl glycol, and 1,6-hexanediol; and a triol
such as glycerin, trimethylolpropane, and hexanetriol. Examples of
the high molecular weight polyol include a polyether polyol such as
polyoxyethylene glycol (PEG), polyoxypropylene glycol (PPG), and
polyoxytetramethylene glycol (PTMG); a condensed polyester polyol
such as polyethylene adipate (PEA), polybutylene adipate (PBA), and
polyhexamethylene adipate (PHMA); a lactone polyester polyol such
as poly-.epsilon.-caprolactone (PCL); a polycarbonate polyol such
as polyhexamethylene carbonate; and an acrylic polyol. Among the
above polyols, the polyol having a weight average molecular weight
ranging from 50 to 2,000, particularly the polyol having a weight
average molecular weight ranging from 100 to 1,000 is preferably
used. These polyols may be used solely or as a mixture of at least
two of them.
[0079] The urethane polyol is a polyol having a urethane bond
formed by the reaction between the polyisocyanate and the polyol,
and a hydroxy group at the terminal. Herein, the amount of the
urethane bond in the urethane polyol preferably ranges from 0.1
mmol to 5 mmol in 1 g of the urethane polyol. The amount of the
urethane bond is correlative with the rigidity of the formed paint
film. If the amount of the urethane bond is less than 0.1 mmol/g,
the concentration of the urethane in the formed paint film is low,
and thus abrasion resistance may be insufficient. On the other
hand, if the amount of the urethane bond is more than 5 mmol/g, the
paint film is so hard that the paint film has lowered followability
to the deformation of the golf ball body, and a small crack may
easily occur.
[0080] In addition, the weight average molecular weight of the
urethane polyol is preferably 4,000 or more, more preferably 4,500
or more, and is preferably less than 10,000, more preferably 9,000
or less. If the weight average molecular weight of the urethane
polyol is less than 4,000, the drying time is longer, and thus
workability and productivity may be lowered. On the other hand, if
the urethane polyol has a high molecular weight of 10,000 or more,
the urethane polyol has a relatively low hydroxy value, the
reacting amount after applied is small, and thus the adhesion of
the paint film to the golf ball body may be lowered. In addition,
if the weight average molecular weight is 9,000 or less, a dense
paint film (or clear paint layer) having little lowering of
adhesion can be formed even in a state of being wetted by
water.
[0081] The hydroxy value of the urethane polyol is preferably 15
mgKOH/g or more, more preferably 25 mgKOH/g or more, and is
preferably 130 mgKOH/g or less, more preferably 120 mgKOH/g or
less. If the hydroxy value of the urethane polyol is less than 15
mgKOH/g, the amount of the urethane polyol reacting with the curing
agent is insufficient, and thus the adhesion strength of the paint
film to the ball body may be hardly obtained. On the other hand, if
the hydroxy value of the urethane polyol is more than 130 mgKOH/g,
the productivity may be lowered because the time for the reaction
between the urethane polyol and the curing agent is longer and the
drying time is longer, and a crack may easily occur at impact.
[0082] The above urethane polyol is obtained by a reaction between
the polyol and the polyisocyanate which are raw materials under a
condition that the molar amount of the hydroxy group included in
the polyol component is excessive to the molar amount of the
isocyanate group included in the polyisocyanate component. In the
above reaction, a solvent, or a conventional catalyst (dibutyl tin
dilaurate, etc.) used in a reaction for synthesizing a urethane can
be used. It is noted that the amount of the urethane bond can be
controlled by adjusting the molecular weight of the polyol which is
the raw material, the mixing ratio of the polyol to the
polyisocyanate, or the like.
[0083] The polyol component contained in the polyol composition is
preferably the above specific urethane polyol itself, but the
polyol composition may contain a polyol having no urethane bond and
being compatible with the urethane polyol, in addition to the
urethane polyol. In this case, the polyol having no urethane bond
is not particularly limited, and the above described raw material
polyol for synthesizing the urethane polyol can be used. In
addition, in the case that the polyol composition contains the
polyol having no urethane bond, the amount of the urethane polyol
in the polyol component contained in the polyol composition is
preferably 50 mass % or more, more preferably 80 mass % or more. If
the amount of the urethane polyol in the polyol component is less
than 50 mass %, the amount of the urethane polyol is relatively
small, and thus the drying time is long.
[0084] Examples of the compound having a hydroxyl group at a part
other than the terminal of the molecule include a modified
polyrotaxane having a hydroxyl group and a hydroxyl group-modified
vinyl chloride-vinyl acetate copolymer.
[0085] The modified polyrotaxane having a hydroxyl group has a
cyclodextrin, a linear molecule piercing through the cyclic
structure of the cyclodextrin, and having blocking groups located
at both terminals of the linear molecule to prevent disassociation
of the cyclic molecule. The polyrotaxane is viscoelastic, since the
cyclodextrin molecule is movable along the linear molecule that
penetrates the cyclodextrin in a skewering manner (pulley effect).
Even if a tension is applied to the polyrotaxane, the tension can
be uniformly dispersed due to the pulley effect. Thus, the
polyrotaxane has an excellent property that a crack or flaw very
hardly occurs, unlike a conventional crosslinked polymer.
[0086] The cyclodextrin is a general term for an oligosaccharide
having a cyclic structure. The cyclodextrin is, for example, a
molecule having 6 to 8 D-glucopyranose residues being linked in a
cyclic shape via an .alpha.-1,4-glucoside bond. Examples of the
cyclodextrin include .alpha.-cyclodextrin (number of glucose units:
6), .beta.-cyclodextrin (number of glucose units: 7), and
.gamma.-cyclodextrin (number of glucose units: 8), and
.alpha.-cyclodextrin is preferable. As the cyclodextrin, one type
may be used solely, and two or more types may be used in
combination.
[0087] The linear molecule is not particularly limited, as long as
it is a linear molecule capable of piercing through the cyclic
structure of the cyclodextrin so that the cyclic structure of the
cyclodextrin is movable along and rotatable around the linear
molecule. Examples of the linear molecule include polyalkylene,
polyester, polyether, and polyacrylic acid. Among them, polyether
is preferable, and polyethylene glycol is particularly preferable.
Polyethylene glycol has less steric hindrance, and thus can be
easily included in the cyclic structure of the cyclodextrin in a
manner of piercing through the cyclic structure of the
cyclodextrin.
[0088] The weight average molecular weight of the linear molecule
is preferably 5,000 or more, more preferably 6,000 or more, and is
preferably 100,000 or less, more preferably 80,000 or less.
[0089] The linear molecule preferably has functional groups at both
terminals thereof. When the linear molecule has the functional
group, the linear molecule can easily react with the blocking
group. Examples of the functional group include a hydroxyl group, a
carboxyl group, an amino group, and a thiol group.
[0090] The blocking groups are not particularly limited, as long as
they are located at both terminals of the linear molecule to
prevent the cyclodextrin from disassociating from the linear
molecule. Examples of the method for preventing the disassociation
include a method of using a bulky blocking group to physically
prevent the disassociation, and a method of using an ionic blocking
group to electrostatically prevent the disassociation. Examples of
the bulky blocking group include a cyclodextrin and an adamantyl
group. The number (pierced amount) of the cyclodextrins pierced by
the linear molecule preferably ranges from 0.06 to 0.61, more
preferably ranges from 0.11 to 0.48, even more preferably ranges
from 0.24 to 0.41, if the maximum pierced amount is deemed as 1.
This is because if the pierced amount is less than 0.06, the pulley
effect may not be exerted, and if the pierced amount exceeds 0.61,
the cyclodextrins are very densely located, so that the movability
of the cyclodextrin may decrease.
[0091] As the polyrotaxane, a polyrotaxane having at least a part
of hydroxyl groups of the cyclodextrin being modified with a
caprolactone chain, is preferred. This is because if at least a
part of hydroxyl groups of the cyclodextrin of the polyrotaxane is
modified with the caprolactone, steric hindrance between the
polyrotaxane and the polyisocyanate is alleviated, so that the
efficiency of a reaction with the polyisocyanate increases.
[0092] As the above modification, for example, the hydroxyl groups
of the cyclodextrin are treated with propylene oxide to
hydroxylpropylate the cyclodextrin, and then .epsilon.-caprolactone
is added to perform ring-opening polymerization. As a result of
this modification, the caprolactone chain --(CO(CH.sub.2).sub.5O)nH
(n is a natural number of 1 to 100) is linked to the exterior side
of the cyclic structure of the cyclodextrin via
--O--C.sub.3H.sub.6--O-- group. "n" represents the degree of
polymerization, and is preferably a natural number of 1 to 100,
more preferably a natural number of 2 to 70, and even more
preferably a natural number of 3 to 40. At another terminal of the
caprolactone chain, a hydroxyl group is formed through the
ring-opening polymerization. The terminal hydroxyl group of the
caprolactone chain can react with the polyisocyanate.
[0093] The ratio of the hydroxyl groups modified with the
caprolactone chain to all the hydroxyl groups (100 mole %) included
in the cyclodextrin before the modification is preferably 2 mole %
or more, more preferably 5 mole % or more, even more preferably 10
mole % or more. If the ratio of the hydroxyl groups modified with
the caprolactone chain falls within the above range, the
hydrophobicity of the polyrotaxane increases, and the reactivity
with the polyisocyanate increases.
[0094] The hydroxyl value of the polyrotaxane is preferably 10 mg
KOH/g or more, more preferably 15 mg KOH/g or more, even more
preferably 20 mg KOH/g or more, and is preferably 400 mg KOH/g or
less, more preferably 300 mg KOH/g or less, even more preferably
220 mg KOH/g or less, particularly preferably 180 mg KOH/g or less.
If the hydroxyl value of the polyrotaxane falls within the above
range, the reactivity with the polyisocyanate increases, and thus
the durability of the paint film becomes more favorable.
[0095] The total molecular weight of the polyrotaxane is preferably
30,000 or more, more preferably 40,000 or more, even more
preferably 50,000 or more, and is preferably 3,000,000 or less,
more preferably 2,500,000 or less, even more preferably 2,000,000
or less, in a weight average molecular weight. If the weight
average molecular weight is 30,000 or more, the paint film has
sufficient strength, and if the weight average molecular weight is
3,000,000 or less, the paint film has sufficient flexibility and
thus approach performance of the golf ball increases. It is noted
that the weight average molecular weight of the polyrotaxane can be
measured, for example, by gel permeation chromatography (GPC) using
polystyrene as a standard substance, tetrahydrofuran as an eluant,
and an organic solvent system GPC column (e.g., "Shodex (registered
trademark) KF series" available from Showa Denko K.K.) as a
column.
[0096] Specific examples of the polyrotaxane modified with the
polycaprolactone include SeRM super polymer SH3400P, SH2400P, and
SH1310P available from Advanced Softmaterials Inc.
[0097] The hydroxyl group modified vinyl chloride-vinyl acetate
copolymer can adjust the tackiness of the paint film while
maintaining the scuff resistance of the paint film. The hydroxyl
group modified vinyl chloride-vinyl acetate copolymer is obtained,
for example, by a method of copolymerizing vinyl chloride, vinyl
acetate and a monomer having a hydroxyl group (e.g., polyvinyl
alcohol, hydroxyalkyl acrylate), or by a method of partially or
completely saponifying a vinyl chloride-vinyl acetate
copolymer.
[0098] The amount of the vinyl chloride component in the hydroxyl
group modified vinyl chloride-vinyl acetate copolymer is preferably
1 mass % or more, more preferably 20 mass % or more, even more
preferably 50 mass % or more, and is preferably 99 mass % or less,
more preferably 95 mass % or less. Specific examples of the
hydroxyl group modified vinyl chloride-vinyl acetate copolymer
include Solbin (registered trademark) A, Solbin AL, and Solbin TA3
available from Nissin Chemical Industry Co., Ltd.
[0099] Preferable embodiments of the polyol composition are an
embodiment containing a urethane polyol, wherein the urethane
polyol includes a polyether diol having a number average molecular
weight in a range from 600 to 3000 as a constituent component
(embodiment 1); and an embodiment containing a polyrotaxane,
wherein the polyrotaxane has a cyclodextrin, a linear molecule
piercing through the cyclic structure of the cyclodextrin, and
blocking groups located at both terminals of the linear molecule to
prevent disassociation of the cyclodextrin, and at least a part of
hydroxyl groups of the cyclodextrin is modified with a caprolactone
chain via --O--C.sub.3H.sub.6--O-- group (embodiment 2).
(Polyisocyanate Composition)
[0100] Examples of the polyisocyanate component of the
polyisocyanate composition include a compound having at least two
isocyanate groups. Examples of the polyisocyanate include an
aromatic polyisocyanate such as 2,4-toluene diisocyanate,
2,6-toluene diisocyanate, a mixture of 2,4-toluene diisocyanate and
2,6-toluene diisocyanate (TDI), 4,4'-diphenylmethane diisocyanate
(MDI), 1,5-naphthylene diisocyanate (NDI),
3,3'-bitolylene-4,4'-diisocyanate (TODD, xylylene diisocyanate
(XDI), tetramethylxylylenediisocyanate (TMXDI), and para-phenylene
diisocyanate (PPDI); an alicyclic polyisocyanate or aliphatic
polyisocyanate such as 4,4'-dicyclohexylmethane diisocyanate
(H.sub.12MDI), hydrogenated xylylenediisocyanate (H.sub.6XDI),
hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI),
and norbornene diisocyanate (NBDI); and derivatives of these
polyisocyanates. In the present invention, as the polyisocyanate,
two or more of polyisocyanates may be used.
[0101] Examples of the polyisocyanate derivative include an
adduct-modified product obtained by a reaction between a
diisocyanate and a polyhydric alcohol; an isocyanurate-modified
product of a diisocyanate; a biuret-modified product; and an
allophanate-modified product. The polyisocyanate derivative from
which a free diisocyanate has been removed is more preferable.
[0102] The amount of the dye and/or pigment contained in the
colored paint film is preferably 0.5 part by mass or more, more
preferably 0.6 part by mass or more, and even more preferably 0.7
part by mass or more, and is preferably 3 parts by mass or less,
more preferably 2.5 parts by mass or less, even more preferably 2.2
parts by mass or less, and most preferably 2.0 parts by mass or
less, with respect to 100 parts by mass of the resin component
constituting the paint film. If the amount is too high, the color
of the golf ball is so deep that the golf ball has a dark color
tone, and if the amount is too small, the desired color tone is not
obtained.
[0103] The nontransparent colored paint film may contain titanium
oxide to enhance opacity. In this case, the amount of titanium
oxide is preferably 0.5 part by mass or more, more preferably 1
part by mass or more, and is preferably 10 parts by mass or less,
more preferably 8 parts by mass or less, with respect to 100 parts
by mass of the resin component constituting the paint film. If the
amount of titanium oxide is 0.5 part by mass or more, the paint
film can be imparted with opacity. In addition, if the amount of
titanium oxide is more than 10 parts by mass, the obtained paint
film may have lowered durability.
[0104] The paint film of the golf ball according to the present
invention preferably contains a filler. If the filler is contained,
the appearance of the paint film may become matte.
[0105] As the filler, a filler conventionally used in a paint can
be used. Examples of the filler include silica (e.g. fused silica,
dry silica (fumed silica), and wet silica such as precipitated
silica, silica gel and colloidal silica), diatomaceous earth,
zeolite, perlite, mica, glass, wollastonite, potassium titanate,
xonotlite, gypsum, aluminum borate, molybdenum disulfide, aramide,
crystalline cellulose, alumina, carbon, metal particle, and metal
oxide particle.
[0106] As the filler, a porous filler is also preferably used. The
porous filler has many fine pores. The shape of the fine pores
included in the porous filler is not particularly limited. The pore
size of the fine pores included in the porous filler is not
particularly limited, but the pore size thereof preferably ranges
from 0.1 nm to 500 nm. The pore size of the fine pores included in
the porous filler varies depending on the type of the porous
filler. For example, zeolite has a pore size in a range from 0.1 nm
to 2 nm, and diatomaceous earth has a pore size of about 300
nm.
[0107] Examples of the porous filler include diatomaceous earth,
zeolite, and perlite. Diatom is a kind of plankton, dead bodies of
diatom deposited on seabed or lake bed, and fossilized into
Diatomaceous earth. Diatomaceous earth primarily contains silica
and has many very fine pores in each particle thereof. Perlite is a
porous material formed when water included in a glassy volcanic
stone such as obsidian, pearlstone and pitchstone is evaporated by
treating the glassy volcanic stone at a high temperature. Zeolite
is a crystalline porous alumino-silicate. Examples of the structure
of zeolite include type A, ferrierite, ZSM-5, mordenite, beta, type
X and type Y. It is noted that zeolite also includes porous
silicalite. The porous filler may be used solely, or two or more of
them may be used in combination.
[0108] The volume average particle size of the filler is preferably
0.5 .mu.m or more, more preferably 1.0 .mu.m or more, and even more
preferably 2.0 .mu.m or more, and is preferably 30 .mu.m or less,
more preferably 20 .mu.m or less, and even more preferably 15 .mu.m
or less. It is noted that the volume particle size distribution is
measured by a laser diffraction method, and the particle size of
50% accumulation (D50) on the volume particle size distribution is
deemed as the volume average particle size.
[0109] The amount of the filler in the paint film is preferably 3
parts by mass or more, more preferably 5 parts by mass or more, and
even more preferably 8 parts by mass or more, and is preferably 200
parts by mass or less, more preferably 150 parts by mass or less,
and even more preferably 120 parts by mass or less, with respect to
100 parts by mass of the resin component. If the amount of the
filler is 3 parts by mass or more, the appearance is matte, and if
the amount of the filler is 200 parts by mass or less, the
appearance is better, and dirt adhesion can be lowered.
[0110] The paint film may further contain an additive that is
conventionally contained in a golf ball paint, such as an
ultraviolet absorber, antioxidant, light stabilizer, fluorescent
brighter, and antiblocking agent. The ultraviolet absorber and
light stabilizer exemplified as the components that can be added in
the intermediate layer and/the cover can also be used in the paint
film.
[Core]
[0111] The core of the golf ball according to the present invention
can be formed from a conventional rubber composition (hereinafter
sometimes referred to as "core rubber composition"). For example,
the core can be molded by heat pressing a rubber composition
containing a base rubber, a co-crosslinking agent and a
crosslinking initiator.
[0112] As the base rubber, particularly preferred is a high-cis
polybutadiene having a cis bond in an amount of 40 mass % or more,
preferably 70 mass % or more, and more preferably 90 mass % or more
in view of its superior resilience. As the co-crosslinking agent,
an .alpha.,.beta.-unsaturated carboxylic acid having 3 to 8 carbon
atoms or a metal salt thereof is preferable, and a metal salt of
acrylic acid or a metal salt of methacrylic acid is more
preferable. As the metal constituting the metal salt, zinc,
magnesium, calcium, aluminum or sodium is preferable, and zinc is
more preferable. The amount of the co-crosslinking agent is
preferably 20 parts by mass or more and 50 parts by mass or less
with respect to 100 parts by mass of the base rubber. In a case
that the .alpha.,.beta.-unsaturated carboxylic acid having 3 to 8
carbon atoms is used as the co-crosslinking agent, a metal compound
(e.g. magnesium oxide) is preferably added. As the crosslinking
initiator, an organic peroxide is preferably used. Specific
examples of the organic peroxide include dicumyl peroxide,
1,1-bis(t-butylperoxy)-3,3,5-trimethylcyclohexane,
2,5-dimethyl-2,5-di(t-butylperoxy) hexane, and di-t-butyl peroxide.
Among them, dicumyl peroxide is preferably used. The amount of the
crosslinking initiator is preferably 0.2 part by mass or more, more
preferably 0.3 part by mass or more, and is preferably 5 parts by
mass or less, more preferably 3 parts by mass or less, with respect
to 100 parts by mass of the base rubber.
[0113] In addition, the core rubber composition may further contain
an organic sulfur compound. As the organic sulfur compound,
diphenyl disulfides, thiophenols, and thionaphthols are preferably
used. The amount of the organic sulfur compound is preferably 0.1
part by mass or more, more preferably 0.3 part by mass or more, and
is preferably 5.0 parts by mass or less, more preferably 3.0 parts
by mass or less, with respect to 100 parts by mass of the base
rubber. The core rubber composition may further contain a
carboxylic acid and/or a salt thereof. As the carboxylic acid
and/or the salt thereof, a carboxylic acid having 1 to 30 carbon
atoms and/or a salt thereof is preferable. The carboxylic acid may
be either an aliphatic carboxylic acid or an aromatic carboxylic
acid (benzoic acid, etc.). The amount of the carboxylic acid and/or
the salt thereof is preferably 1 part by mass or more and 40 parts
by mass or less with respect to 100 parts by mass of the base
rubber.
[Method for Producing Golf Ball]
[0114] The core of the golf ball according to the present invention
is molded, for example, by heat pressing the core rubber
composition. The molding conditions for heat pressing the core
rubber composition may be suitably determined depending on the
rubber composition. Generally, the molding is carried out at a
temperature in a range from 130.degree. C. to 200.degree. C. and a
pressure in a range from 2.9 MPa to 11.8 MPa for 10 to 60 minutes.
For example, it is preferable that the molding is carried out by
heating the core rubber composition at a temperature ranging from
130.degree. C. to 200.degree. C. for 10 minutes to 60 minutes, or
alternatively, by molding the core rubber composition in a two-step
heating, i.e. heated at a temperature ranging from 130.degree. C.
to 150.degree. C. for 20 minutes to 40 minutes and then heated at a
temperature ranging from 160.degree. C. to 180.degree. C. for 5
minutes to 15 minutes.
[0115] The intermediate layer composition and the cover composition
can be obtained, for example, by dry blending the resin component,
dye and/or pigment, and optional additives. Further, the dry
blended mixture may be extruded into a pellet form. In the dry
blending, for example, a mixer capable of blending raw materials in
a pellet form is preferably used, a tumbler type mixer is more
preferably used. The extrusion can be carried out with a
conventional extruder such as a single-screw extruder, a twin-screw
extruder, and a twin-screw/single-screw extruder.
[0116] The method for molding the intermediate layer is not
particularly limited, and examples thereof include a method of
molding the intermediate layer composition into a hemispherical
half shell in advance, covering the spherical core with two of the
half shells, and compression molding the spherical core with two of
the half shells; and a method of injection molding the intermediate
layer composition onto the spherical core to cover the spherical
core.
[0117] In case of injection molding the intermediate layer
composition onto the spherical core to form the intermediate layer,
it is preferred to use upper and lower molds, each having a
hemispherical cavity. When molding the intermediate layer by the
injection molding method, the hold pin is protruded to hold the
spherical core, and the intermediate layer composition which has
been heated and melted is charged and then cooled to form the
intermediate layer.
[0118] When molding the intermediate layer by the compression
molding method, the molding of the half shell may be performed by
either a compression molding method or an injection molding method,
and the compression molding method is preferable. Compression
molding the intermediate layer composition into the half shell may
be carried out, for example, under a pressure of 1 MPa or more and
20 MPa or less at a temperature of -20.degree. C. or more and
+70.degree. C. or less relative to the flow beginning temperature
of the intermediate layer composition. If the molding is carried
out under the above conditions, the half shell having a uniform
thickness can be formed. Examples of the method for molding the
intermediate layer by using the half shell include a method of
covering the spherical core with two of the half shells, and
compression molding the spherical core with two of the half shells.
Compression molding the half shells into the intermediate layer may
be carried out, for example, under a pressure of 0.5 MPa or more
and 25 MPa or less at a temperature of -20.degree. C. or more and
+70.degree. C. or less relative to the flow beginning temperature
of the intermediate layer composition. If the molding is carried
out under the above conditions, the intermediate layer having a
uniform thickness can be formed.
[0119] It is noted that the molding temperature means the highest
temperature where the temperature at the surface of the concave
portion of the lower mold reaches from closing the mold to opening
the mold. In addition, the flow beginning temperature of the
composition may be measured using the thermoplastic resin
composition in a pellet form under the following conditions with
"Flow Tester CFT-500" available from Shimadzu Corporation.
[0120] Measuring conditions: Plunger area: 1 cm.sup.2, Die length:
1 mm, Die diameter: 1 mm, Load: 588.399 N, Starting temperature:
30.degree. C., and Temperature rising rate: 3.degree. C./min.
[0121] The method for molding the cover from the cover composition
is not particularly limited, and examples thereof include a method
of injection molding the cover composition directly onto the
intermediate layer; and a method of molding the cover composition
into hollow shells, covering the spherical body having the
intermediate layer formed thereon with a plurality of the hollow
shells and compression molding the spherical body with a plurality
of the hollow shells (preferably a method of molding the cover
composition into hollow half shells, covering the spherical body
having the intermediate layer formed thereon with two of the half
shells and compression molding the spherical body with two of the
half shells). The golf ball body having the cover formed thereon is
ejected from the mold, and as necessary, the golf ball body is
preferably subjected to surface treatments such as deburring,
cleaning, and sandblast. In addition, if desired, a mark may also
be formed thereon.
[0122] In the present invention, the first region and the second
region are formed on the golf ball surface, for example, by
producing a hollow first shell with the first color and a hollow
second shell with the second color, covering the spherical body
having the intermediate layer formed thereon with the first shell
and the second shell, and compression molding the spherical body
with the first shell and the second shell. In addition, a
hemispherical first region with the first color and the
hemispherical second region with the second color can be formed on
the golf ball surface by molding a hollow half shell with the first
color and a hollow half shell with the second color, covering the
spherical body having the intermediate layer formed thereon with
two of the half shells, and compression molding the spherical body
with two of the half shells.
[0123] Dimples are preferably formed on the cover of the golf ball
according to the present invention. The total number of the dimples
formed on the cover is preferably 200 or more and 500 or less. If
the total number of the dimples is less than 200, the dimple effect
is hardly obtained, and if the total number of the dimples exceeds
500, the dimple effect is hardly obtained because the size of the
respective dimples is small. The shape (shape in a plan view) of
the dimples includes, for example, but is not limited to, a circle;
a polygonal shape such as a roughly triangular shape, a roughly
quadrangular shape, a roughly pentagonal shape, and a roughly
hexagonal shape; and other irregular shape. The shape of the
dimples may be employed solely, or two or more of the shapes may be
employed in combination.
[0124] The golf ball having the cover formed thereon is ejected
from the mold, and as necessary, the golf ball is preferably
subjected to surface treatments such as deburring, cleaning, and
sandblast. In addition, if desired, a paint film or a mark may also
be formed thereon.
[0125] The paint film of the golf ball according to the present
invention can be formed by painting the paint on the surface of the
golf ball body. The method of applying the paint is not
particularly limited, a conventional method can be adopted, and
examples thereof include a spray coating and electrostatic
coating.
[0126] In the case that the first region with the first color or
the second region with the second color is formed by the colored
paint film, the paint film can be formed by applying the paint, for
example, to the desired shape of the first region or the second
region.
[0127] In case of spray coating a two-component curing type
urethane paint as the paint, the polyisocyanate composition and the
polyol composition are fed with respective pumps and continuously
mixed with a line mixer located in the stream line just before the
air gun, and the obtained mixture is air-sprayed. Alternatively,
the polyol composition and the polyisocyanate composition are
air-sprayed respectively with an air spray system provided with a
device for controlling the mixing ratio thereof. The paint
application may be conducted by spraying the paint one time or
overspraying the paint multiple times.
[0128] The paint applied on the golf ball body is dried, for
example, at a temperature in a range of from 30.degree. C. to
70.degree. C. for 1 hour to 24 hours, to form the paint film.
[Construction of Golf Ball]
[0129] The construction of the golf ball according to the present
invention is not particularly limited, as long as the golf ball
comprises a core and a cover disposed outside of the core. In a
preferable embodiment, the golf ball according to the present
invention further comprises at least one intermediate layer between
the core and the cover. Examples of the construction of the golf
ball include a two-piece golf ball composed of a spherical core and
a cover covering the spherical core; a three-piece golf ball
composed of a spherical core, one intermediate layer covering the
spherical core, and a cover covering the intermediate layer; and a
multi-piece golf ball composed of a spherical core, at least two
intermediate layers covering the spherical core, and a cover
covering the intermediate layers.
[0130] In case of having a plurality of intermediate layers, the
color tone of the outermost layer of the intermediate layers is
measured.
[0131] The core of the golf ball according to the present invention
is preferably spherical. The diameter of the spherical core is
preferably 34.8 mm or more, more preferably 36.8 mm or more, and
even more preferably 38.8 mm or more, and is preferably 42.2 mm or
less, more preferably 41.8 mm or less, even more preferably 41.2 mm
or less, and most preferably 40.8 mm or less. If the diameter of
the spherical core is 34.8 mm or more, the cover is not too thick
and thus the resilience is better. On the other hand, if the
diameter of the spherical core is 42.2 mm or less, the cover is not
too thin and thus the cover functions well.
[0132] The thickness of the intermediate layer is preferably 0.8 mm
or more, more preferably 0.9 mm or more, and even more preferably
1.0 mm or more, and is preferably 2.2 mm or less, more preferably
2.0 mm or less, and even more preferably 1.8 mm or less. If the
thickness of the intermediate layer is 0.8 mm or more, the
intermediate layer is more easily molded, and if the thickness of
the intermediate layer is 2.2 mm or less, the core has a relatively
large diameter and thus the golf ball has enhanced resilience
performance. In case of having a plurality of intermediate layers,
the total thickness of the intermediate layers preferably falls
within the above range.
[0133] The cover of the golf ball according to the present
invention is preferably single layered. The thickness of the cover
is preferably 0.3 mm or more, more preferably 0.4 mm or more, and
even more preferably 0.5 mm or more, and is preferably 2.0 mm or
less, more preferably 1.5 mm or less, and even more preferably 1.0
mm or less. If the thickness of the cover is 0.3 mm or more, the
cover is more easily molded, and if the thickness of the cover is
2.0 mm or less, the core has a relatively large diameter and thus
the golf ball has enhanced resilience performance.
[0134] The thickness of the paint film is not particularly limited,
and is preferably 5 .mu.m or more, more preferably 7 .mu.m or more,
and is preferably 50 .mu.m or less, more preferably 40 .mu.m or
less, and even more preferably 30 .mu.m or less. If the thickness
is less than 5 .mu.m, the paint film tends to be easily worn off
due to the continued use of the golf ball, and if the thickness
exceeds 50 .mu.m, the dimple effect may be lowered, and the flight
performance of the golf ball tends to be lowered.
[0135] The golf ball according to the present invention preferably
has a diameter in a range from 40 mm to 45 mm. In light of
satisfying the regulation of US Golf Association (USGA), the
diameter is preferably 42.67 mm or more. In light of prevention of
air resistance, the diameter is preferably 44 mm or less, more
preferably 42.80 mm or less. In addition, the golf ball preferably
has a mass of 40 g or more and 50 g or less. In light of obtaining
greater inertia, the mass is preferably 44 g or more, more
preferably 45.00 g or more. In light of satisfying the regulation
of USGA, the mass is particularly preferably 45.93 g or less.
[0136] FIG. 5 is a partially cutaway cross-sectional view of a golf
ball 1 according to one embodiment of the present invention. The
golf ball 1 comprises a spherical core 2, an intermediate layer 3
covering the spherical core, and a cover 4 covering the
intermediate layer. A plurality of dimples 31 are formed on the
surface of the cover. Other portions than the dimples 31 on the
golf ball surface are lands 32. The golf ball comprises a paint
layer 5 on the outside of the cover.
EXAMPLES
[0137] Next, the present invention will be described in detail by
way of examples. However, the present invention is not limited to
the examples described below. Various changes and modifications
without departing from the spirit of the present invention are
included in the scope of the present invention.
[Evaluation Method]
[0138] (1) Color tone
[0139] The color tone of the intermediate layer and the golf ball
surface was measured with a color difference meter ("CM-350d"
available from KONICA MINOLTA, INC.). The color tone of the golf
ball was measured in a state that the paint film was formed on the
golf ball body. [0140] Measuring conditions [0141] Measuring
wavelength range: 360 nm to 740 nm [0142] Measuring region
(diameter): 8 mm.phi. [0143] Measuring time: 1 second [0144] (2)
Easiness of finding a golf ball on the rough
[0145] The golf balls were sunk in the rough (length of grass: 5 cm
to 10 cm) at a distance of 1 m to 10 m from the tester with an
interval of 1 m. The longest distance at which the tester correctly
told the color combination of these balls was measured. Evaluation
was conducted by twenty testers, and the average distance was
calculated. [0146] (3) Uncomfortableness at shot
[0147] The golf ball was placed such that the boundary between the
hemispherical first region and the hemispherical second region
faces the tester, and twenty testers were allowed to address the
golf balls with a driver. The number of people who answered that he
or she felt uncomfortable was counted. [0148] E (Excellent): 17 to
20 persons answered that there was no uncomfortableness. [0149] G
(Good): 13 to 16 persons answered that there was no
uncomfortableness. [0150] F (Fair): 9 to 12 persons answered that
there was no uncomfortableness. [0151] P (Poor): 8 or less persons
answered that there was no uncomfortableness.
[Production of Golf Ball]
[0151] [0152] (1) Production of core
[0153] The rubber composition having the formulation shown in Table
1 was kneaded with a kneading roll, and heat-pressed at a
temperature of 170.degree. C. for 20 minutes in upper and lower
molds, each having a hemispherical cavity, to obtain a spherical
core having a diameter of 39.7 mm. It is noted that the amount of
barium sulfate was adjusted such that the obtained golf ball had a
mass of 45.3 g.
TABLE-US-00001 TABLE 1 Core composition Parts by mass Polybutadiene
100 Zinc acrylate 25 Zinc oxide 5 Barium sulfate Appropriate amount
.sup.*1) PBDS 0.3 Dicumyl peroxide 0.8 .sup.*1) Barium sulfate: the
amount was adjusted such that the golf ball had a mass of 45.3
g.
[0154] The materials used in Table 1 are shown as follows.
[0155] Polybutadiene rubber: high-cis polybutadiene "BR730"
(cis-1,4 bond amount=96 mass %, 1,2-vinyl bond amount=1.3 mass %,
Moony viscosity (ML.sub.1+4 (100.degree. C.))=55, molecular weight
distribution (Mw/Mn)=3) available from JSR Corporation
[0156] Zinc acrylate: "ZNDA-90S" available from Nisshoku Techno
Fine Chemical Co., Ltd.
[0157] Zinc oxide: "Ginrei R" available from Toho Zinc Co.,
Ltd.
[0158] Barium sulfate: "Barium sulfate BD" available from Sakai
Chemical Industry Co., Ltd.
[0159] PBDS: bis(pentabromodiphenyl) disulfide available from
Kawaguchi Chemical Industry Co., Ltd.
[0160] Dicumyl peroxide: "Percumyl (register trademark) D"
available from NOF Corporation [0161] (2) Formation of intermediate
layer
[0162] According to the formulations shown in Table 2, the
materials were mixed with a twin-screw kneading extruder to prepare
the intermediate layer resin compositions in a pellet form. The
extruding conditions were a screw diameter of 45 mm, a screw
rotational speed of 200 rpm, and a screw L/D=35, and the mixture
was heated to 160.degree. C. to 230.degree. C. at the die position
of the extruder. The obtained intermediate layer resin composition
was injection molded onto the spherical core obtained above to form
the intermediate layer having a thickness of 1 mm.
TABLE-US-00002 TABLE 2 Intermediate layer resin composition No. 1 2
3 Himilan 1605 50 50 50 Himilan AM7329 50 50 50 FX-305 -- 1 --
GPX-17 -- -- 1.5 GPL-15 -- 1 3 Titanium oxide 4 0.5 0.05
Formulation: Parts by Mass
[0163] Himilan 1605: sodium ion-neutralized ethylene-methacrylic
acid copolymer ionomer resin available from Dow-Mitsui
Polychemicals Co., Ltd.
[0164] Himilan AM7329: zinc ion-neutralized ethylene-methacrylic
acid copolymer ionomer resin available from Dow-Mitsui
Polychemicals Co., Ltd.
[0165] Titanium oxide: "A-220" available from Ishihara Sangyo
Kaisha, Ltd.
[0166] FX305: Lemon Yellow available from Sinloihi Co., Ltd.
[0167] GPX-17: Saturn yellow available from DayGlo Color Corp.
[0168] GPL-15: Blaze orange available from DayGlo Color Corp.
[0169] (3) Molding of cover
[0170] The materials shown in Table 3 were dry blended, and mixed
with a twin-screw kneading extruder, to prepare the cover (half
shell) compositions in a pellet form. The extruding conditions of
the cover (half shell) compositions were a screw diameter of 45 mm,
a screw rotational speed of 200 rpm, and screw L/D=35, and the
mixtures were heated to 150.degree. C. to 230.degree. C. at the die
position of the extruder.
[0171] The compression molding of half shells was conducted as
follows. The obtained cover resin composition in the pellet form
was charged one by one into each of the depressed part of the lower
mold of a half shell molding mold, and pressed to mold half shells.
The compression molding was conducted under the following
conditions: a molding temperature of 170.degree. C., a molding time
of 5 minutes, and a molding pressure of 2.94 MPa. The spherical
core having the intermediate layer formed thereon was
concentrically covered with two half shells, i.e. half shell A and
half shell B which had a color tone different from each other, and
compression-molded to form the cover. The compression molding was
conducted under the following conditions: a molding temperature of
150.degree. C., a molding time of 2 minutes, and a molding pressure
of 9.8 MPa. The cover has a thickness of 0.5 mm.
TABLE-US-00003 TABLE 3 Cover (half shell) composition No. 1 2 3 4 5
6 7 8 Elastollan NY80A 100 100 100 100 100 100 100 100 FP-3000 -- 2
-- -- -- -- -- -- FX-305 -- 1 -- -- -- -- -- -- FX-327 -- -- -- --
-- -- 1.5 -- GPX-17 -- -- 2 -- -- -- -- -- GPL-15 -- -- 4 -- -- --
-- -- ZQ-14 -- -- -- -- -- -- -- 0.015 ZQ-17 -- -- -- 0.2 -- -- --
5 ZQ-18 -- -- -- 3 -- -- -- -- FP113 -- -- -- -- 3 -- -- -- FP1050
-- -- -- -- -- 3 -- -- JF-90 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2
Titanium oxide 4 0.1 0.05 0.5 0.05 0.5 0.1 0.1
Formulation: Parts by Mass
[0172] The materials used in Table 3 are shown as follows.
[0173] Urethane resin: Elastollan (registered trademark) NY80A:
polyurethane elastomer (polyol component: polytetramethylene ether
glycol, polyisocyanate component:
dicyclohexylmethane-4,4'-diisocyanate, chain extender:
1,4-butanediol) (Shore A hardness: 80) available from BASF Japan
Ltd.
[0174] JF-90: light stabilizer available from Johoku Chemical Co.
Ltd.
[0175] Titanium oxide: "A220" available from Ishihara Sangyo
Kaisha, Ltd.
[0176] EPO Color FP3000: fluorescent pigment having fluorescent dye
dispersed and fixed in benzoguanamine resin (condensation product
of benzoguanamine and formaldehyde) available from Ukseung Chemical
Co., Ltd.
[0177] FX305: Lemon yellow available from Sinloihi Co., Ltd.
[0178] FX-327: Magenta available from Sinloihi Co., Ltd.
[0179] GPX-17: Saturn yellow available from DayGlo Color Corp.
[0180] GPL-15: Blaze orange available from DayGlo Color Corp.
[0181] ZQ-14: Fire orange (fluorescent pigment having fluorescent
dye dispersed and fixed in polyester resin) available from DayGlo
Color Corp.
[0182] ZQ-17: Saturn yellow (fluorescent pigment having fluorescent
dye dispersed and fixed in polyester resin) available from DayGlo
Color Corp.
[0183] ZQ-18: Signal green (fluorescent pigment having fluorescent
dye dispersed and fixed in polyester resin) available from DayGlo
Color Corp.
[0184] FP113: Red available from Ukseung Chemical Co., Ltd.
[0185] FP1050: Blue available from Ukseung Chemical Co., Ltd.
[0186] (4) Preparation of paint composition
[Polyol Composition No. 1 (Urethane Polyol)]
[0187] Polyoxytetramethylene glycol (PTMG, number average molecular
weight: 650) and trimethylolpropane (TMP) were dissolved in a mixed
solvent (mass ratio of toluene/methyl ethyl ketone: 15/85). The
molar ratio (PTMG:TMP) was 1.8:1.0. Dibutyltin dilaurate was added
as a catalyst into the solution in an amount of 0.1 mass % with
respect to the total amount of the base agent. While keeping the
temperature of the polyol solution at 80.degree. C., isophorone
diisocyanate (IPDI) was added dropwise and mixed. The molar ratio
(NCO/OH) of the mixed liquid was 0.6. After the dropwise addition
of isophorone diisocyanate was finished, stirring was continued
until the isocyanate component in the mixed liquid disappeared.
Then, the mixed liquid was cooled to a normal temperature to
prepare the polyol composition No. 1 containing a urethane polyol
as the base agent. In the polyol composition No. 1, the amount of
the solid component was 30 mass %, the amount of PTMG was 67 mass
%, the hydroxy value of the solid component was 67.4 mgKOH/g, and
the weight average molecular weight of the urethane polyol was
4867. In the case that the filler was added, the filler was added
in the polyol composition. The amount of the filler was 45 parts by
mass with respect to 100 parts by mass of the polyol composition
constituting the paint film.
[Polyisocyanate Composition No. 1]
[0188] The isocyanurate-modified product of hexamethylene
diisocyanate (trade name "Duranate TKA-100" available from Asahi
Kasei Chemicals Corporation, NCO amount: 21.7 mass %) in an amount
of 30 parts by mass, the biuret-modified product of hexamethylene
diisocyanate (trade name "Duranate 21S-75E" available from Asahi
Kasei Chemicals Corporation, NCO amount: 15.5 mass %) in an amount
of 30 parts by mass, and the isocyanurate-modified product of
isophorone diisocyanate (trade name "Desmodur Z4470" available from
BAYER Corporation, NCO amount: 11.9 mass %) in an amount of 40
parts by mass were mixed. Methyl ethyl ketone, n-butyl acetate and
toluene were added as a solvent in the above mixture and mixed to
obtain the polyisocyanate composition No. 1 as the curing agent.
The concentration of the polyisocyanate component in the
composition was 60 mass %.
[0189] The polyol composition and the polyisocyanate composition
were mixed in the mixing ratio shown in Table 4 to prepare the
paint compositions. The surface of the golf ball bodies obtained
above was treated with sandblast and marked. The paint was applied
with a spray gun, and dried for 24 hours in an oven at a
temperature of 40.degree. C. to obtain golf balls having a diameter
of 42.7 mm and a mass of 45.3 g.
TABLE-US-00004 TABLE 4 Paint composition No. 1 2 Polyol composition
No. 1 100 100 Polyisocyanate composition No. 1 29 29 Silica
(average particle size: 7 .mu.m) -- 45
Formulation: Parts by Mass
[0190] Silica: CARPLEX FPS-1 (wet silica, volume average particle
size: 7.0 .mu.m) available from Evonik Industries AG
[0191] The golf ball body was placed in a rotating member provided
with a prong, the rotating member was allowed to rotate at 300 rpm,
and application of the paint was conducted by spacing a spray
distance (7 cm) between the air gun and the golf ball body while
moving the air gun in an up and down direction. The painting
interval in the overpainting operation was set to 1.0 second.
Application of the paint was conducted under the air gun spraying
conditions of overpainting: two times, a spraying air pressure:
0.15 MPa, a compressed air tank pressure: 0.10 MPa, a painting time
for one application: 1 second, an atmosphere temperature:
20.degree. C. to 27.degree. C., and an atmosphere humidity: 65% or
less. Evaluation results of the obtained golf balls are shown in
Table 5.
TABLE-US-00005 TABLE 5 Golf ball No. 1 2 3 4 5 6 7 8 Core
formulation A A A A A A A A Core diameter (mm) 39.7 39.7 39.7 39.7
39.7 39.7 39.7 39.7 Intermediate layer resin composition No. 1 2 2
2 2 2 3 3 Intermediate layer thickness (mm) 1.0 1.0 1.0 1.0 1.0 1.0
1.0 1.0 Cover composition No. for half shell A 1 2 2 2 2 2 2 8
Cover composition No. for half shell B 2 3 4 5 6 7 3 3 Cover
thickness (mm) 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 Paint composition
No. 1 1 1 1 1 1 1 1 Color tone of intermediate layer White Yellow
Yellow Yellow Yellow Yellow Orange Orange H0 219 77 77 77 77 77 20
20 S0 31 91 91 91 91 91 82 82 L0 93 68 68 68 68 68 58 58 Color tone
of first region (half shell A) White Yellow Yellow Yellow Yellow
Yellow Yellow Yellow H1 225 74 74 74 74 74 72 59 S1 71 83 83 83 83
83 52 44 L1 91 58 58 58 58 58 65 64 Color tone of second region
(half shell B) Yellow Orange Green Red Blue Pink Orange Orange H2
75 14 160 355 202 348 13 13 S2 90 100 100 74 100 50 80 80 L2 56 60
39 57 38 55 57 57 |H1 - H2| 150 60 86 281 128 274 59 46 |H0 - H1| 6
3 3 3 3 3 52 39 |H0 - H2| 144 63 83 278 125 271 7 7
Uncomfortableness at shot P G F F P F G G Easiness of finding a
golf ball on the 7.6 6.9 6.7 7.2 7.1 7.4 6.6 6.4 rough (m) Golf
ball No. 9 10 11 12 13 14 15 Core formulation A A A A A A A Core
diameter (mm) 39.7 39.7 39.7 39.7 39.7 39.7 39.7 Intermediate layer
resin composition No. 2 1 2 2 2 3 1 Intermediate layer thickness
(mm) 1.0 1.0 1.0 1.0 1.0 1.0 1.0 Cover composition No. for half
shell A 1 1 2 2 2 1 2 Cover composition No. for half shell B 2 3 5
6 8 2 8 Cover thickness (mm) 0.5 0.5 0.5 0.5 0.5 0.5 0.5 Paint
composition No. 1 1 2 2 1 1 1 Color tone of intermediate layer
Yellow White Yellow Yellow Yellow Orange White H0 77 219 77 77 77
20 219 S0 91 31 91 91 91 82 31 L0 68 93 68 68 68 58 93 Color tone
of first region (half shell A) White White Yellow Yellow Yellow
White Yellow H1 223 225 74 74 80 224 75 S1 57 71 83 83 79 57 90 L1
92 91 52 52 65 93 56 Color tone of second region (half shell B)
Yellow Orange Red Blue Yellow Yellow Yellow H2 74 15 354 201 73 72
71 S2 83 100 80 100 62 52 73 L2 58 60 56 38 64 65 56 |H1 - H2| 149
210 280 127 7 152 4 |H0 - H1| 146 6 3 3 3 204 144 |H0 - H2| 3 204
277 124 4 52 148 Uncomfortableness at shot F P F P E F E Easiness
of finding a golf ball on the 7.0 7.5 6.4 7.3 6.3 5.9 5.5 rough
(m)
[0192] It is apparent from Table 5 that a golf ball comprising a
core and a cover disposed outside of the core, wherein a surface of
the golf ball has a first region with a first color and a second
region with a second color, the first color has hue H1 represented
by H value in HSL color space, the second color has hue H2
represented by H value in HSL color space, and the H1 and the H2
satisfy a specific relationship, has high visibility and little
uncomfortableness at shot.
[0193] This application is based on Japanese patent application No.
2020-214235 filed on Dec. 23, 2020, the contents of which are
hereby incorporated by reference.
* * * * *
References