U.S. patent application number 14/634043 was filed with the patent office on 2015-06-25 for multi-core golf ball having increased initial velocity.
This patent application is currently assigned to NIKE, Inc.. The applicant listed for this patent is NIKE, Inc.. Invention is credited to Chien-Hsin Chou, Yasushi Ichikawa, Jun Ichinose, Hideyuki Ishii, Chin-Shun Ko, Chen-Tai Liu, Arthur Molinari.
Application Number | 20150174457 14/634043 |
Document ID | / |
Family ID | 47747064 |
Filed Date | 2015-06-25 |
United States Patent
Application |
20150174457 |
Kind Code |
A1 |
Ishii; Hideyuki ; et
al. |
June 25, 2015 |
Multi-Core Golf Ball Having Increased Initial Velocity
Abstract
A golf ball having certain relationships and values of its
initial velocities at various club head speeds is provided. The
golf ball may achieve an initial velocity of at least about 173 mph
at a club head speed of about 125 mph, therefore achieving an
increased total shot distance. The golf ball has multiple layers
making up its core, and the golf ball may be a four piece golf
ball.
Inventors: |
Ishii; Hideyuki; (Portland,
OR) ; Ichikawa; Yasushi; (Tualatin, OR) ;
Molinari; Arthur; (Portland, OR) ; Chou;
Chien-Hsin; (Yun-lin Hsien, TW) ; Ko; Chin-Shun;
(Kaohsiung, TW) ; Liu; Chen-Tai; (Yun-Lin Hsien,
TW) ; Ichinose; Jun; (Kodaira Tokyo, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
NIKE, Inc. |
Beaverton |
OR |
US |
|
|
Assignee: |
NIKE, Inc.
Beaverton
OR
|
Family ID: |
47747064 |
Appl. No.: |
14/634043 |
Filed: |
February 27, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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13587636 |
Aug 16, 2012 |
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14634043 |
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61526624 |
Aug 23, 2011 |
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61526621 |
Aug 23, 2011 |
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Current U.S.
Class: |
473/376 |
Current CPC
Class: |
A63B 37/0045 20130101;
A63B 37/0046 20130101; A63B 37/0084 20130101; C08L 2205/02
20130101; A63B 37/0003 20130101; A63B 37/0024 20130101; A63B
37/0033 20130101; A63B 37/0076 20130101; A63B 37/0078 20130101;
A63B 37/008 20130101; A63B 37/0041 20130101; A63B 37/0051 20130101;
A63B 37/0068 20130101; C08L 23/0876 20130101; A63B 37/0061
20130101; A63B 37/0064 20130101; A63B 37/0087 20130101; A63B
37/0031 20130101; A63B 37/0043 20130101; A63B 37/0062 20130101;
A63B 37/0075 20130101; A63B 37/0065 20130101; C08L 23/0876
20130101; C08L 23/0876 20130101 |
International
Class: |
A63B 37/00 20060101
A63B037/00 |
Claims
1. A golf ball comprising: an inner core, the inner core being
formed primarily of at least one thermoplastic highly neutralized
polymer, and the inner core has a diameter of from about 20 mm to
about 26 mm; an outer core layer, the outer core substantially
surrounding the inner core and being made primarily of a thermoset
rubber, and the outer core layer has a thickness of from about 5 mm
to about 9 mm; an inner cover layer, the inner cover layer
substantially surrounding the outer core layer; and an outer cover
layer, the outer cover layer substantially surrounding the inner
cover layer; wherein the inner core has a compression deformation
of from about 3.5 mm to about 4.1 mm, the outer core layer has a
compression deformation of from about 2.7 mm to about 3.3 mm, and a
ratio of the compression deformation of the inner core to the
compression deformation of the outer core layer is from about 1.1
to about 1.3; the inner core having a first COR, the outer core
having a second COR, the second COR being greater than the first
COR and having a value of at least 0.8; and wherein the golf ball
has an initial velocity measured at a club head speed of about 125
mph of at least about 174 mph.
2. The golf ball of claim 1, wherein the golf ball has an initial
velocity measured at a club head speed of about 80 mph of at least
about 88 mph.
3. The golf ball of claim 1, wherein the inner cover layer is
formed primarily of a thermoplastic material, has a surface Shore D
hardness of at least 60, and has a thickness of less than 1 mm; and
the outer cover layer comprises a thermoplastic material, has a
surface Shore D hardness of from 50 to 60, and has a thickness that
is greater than the thickness of the inner cover layer.
4. The golf ball of claim 1, wherein the outer cover layer
comprises a crosslinked thermoplastic polyurethane that is the
reaction product of unsaturated bonds located in hard segments of
the polyurethane polymer, as catalyzed by a free radical initiator;
the unsaturated bonds being present in an unsaturated diol of
formula (2): ##STR00003## in which R is a substituted or
unsubstituted alkyl group, and x and y are integers independently
having values of 1 to 4. In particular embodiments, x and y may
both have values of 1, 2, 3 or 4. In other embodiments, x and y may
each have different values from 1 to 4.
5. The golf ball of claim 4, wherein the unsaturated diol is
trimethylolpropane monoallylether.
6. The golf ball of claim 1, wherein the golf ball has a COR of
about 0.80 or less.
7. A golf ball comprising: an inner core, the inner core consisting
essentially of at least one highly neutralized polymer; an outer
core layer, the outer core substantially surrounding the inner core
and being made primarily of a thermoset rubber; and an inner cover
layer, the inner cover layer substantially surrounding the outer
core layer; and an outer cover layer, the outer cover layer
substantially surrounding the inner cover layer; wherein the golf
ball has an initial velocity measured at a club head speed of about
125 mph of at least about 174 mph.
8. The golf ball of claim 7, wherein the golf ball has an initial
velocity measured at a club head speed of about 80 mph of at least
88 mph, and the difference between the initial velocity at a club
head speed of about 125 mph and the initial velocity at the club
head speed of about 80 mph is at least about 86.
9. The golf ball of claim 7, wherein the inner core consists
essentially of a mixture of two highly neutralized polymers.
10. The golf ball of claim 7, wherein the inner core has a diameter
of from about 20 mm to about 26 mm; the outer core layer has a
thickness of from about 5 mm to about 9 mm; the inner cover layer
has a thickness of less than 1 mm; and the outer cover layer has a
thickness that is greater than the thickness of the inner cover
layer.
11. The golf ball of claim 7, wherein the inner core has a first
COR; the outer core layer has a second COR; the second COR being
greater than the first COR, the second COR being 0.80 or more; and
the first COR being greater than the golf ball COR.
12. The golf ball of claim 11, wherein the golf ball has a COR of
about 0.80 or less.
13. The golf ball of claim 7, wherein the inner core has a surface
Shore D hardness of at least about 60; the outer core layer has a
surface Shore D hardness of from about 50 to about 60; the inner
cover layer has a surface Shore D hardness of at least 60; and the
outer cover layer has a surface Shore D hardness of from about 50
to about 60.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is a divisional patent application of U.S.
application Ser. No. 13/587,636, entitled "Multi-Core Golf Ball
Having Increased Initial Velocity," filed on Aug. 16, 2012 which
claims priority under 35 U.S.C. .sctn.119(e) to U.S. Provisional
Patent Application No. 61/526,621, entitled "Multi-Core Golf Ball
Having Increased Initial Velocity At High Swing Speeds Relative To
Low Swing Speeds," filed on Aug. 23, 2011, and to U.S. Provisional
Patent Application No. 61/526,624, entitled "Multi-Core Golf Ball
Having Increased Initial Velocity," filed on Aug. 23, 2011. These
applications are hereby incorporated by reference in their
entirety.
BACKGROUND
[0002] The present invention relates generally to golf balls. In
particular, the present disclosure relates to golf balls with a
core made of up at least two structural components with certain
values of its initial velocity off the tee, and certain
relationships among the initial velocity values.
[0003] Golf is an increasing popular sport at both the professional
and amateur levels. Generally, a mass produced golf ball should be
able to meet the requirements of golfers of a wide variety of
ability levels. One important difference between recreational
golfers and professional golfers is the speed at which they swing
the club during a drive, known as club head speed. Recreational
players usually have a driver club head speed of lower than 100
mph. On the other hand, professional players usually have a driver
club head speed of higher than 125 mph.
[0004] The golf club speed is related to a golf ball's initial
velocity. Initial velocity is the measure of a golf ball's
instantaneous speed immediately after being struck by a golf club
off of the tee. Initial velocity is often related to the distance
the shot will travel. Golfers generally prefer golf balls that
achieve a higher initial velocity in order for their shots to
achieve longer distances.
[0005] Some premium balls currently known and commercially
available can satisfy the needs of low club head speed players, and
mid club head speed players. However, these balls may not have a
good initial velocity under a head speed of 125 mph or more.
[0006] Therefore, there is a need in the art for a golf ball that
satisfies the need of golfers having different ability levels by
achieving a bigger difference of golf ball initial velocity between
low and high head speed.
SUMMARY
[0007] Generally, this disclosure relates to golf balls having at
least two core structural components, where the golf ball achieves
a wide range of initial velocities under different club head
speeds. Furthermore, this disclosure relates to golf balls that
achieve a high initial velocity under high club head speeds.
[0008] In one aspect, this disclosure provides a golf ball
comprising: an inner core, the inner core comprising a
thermoplastic resin; an outer core layer, the outer core
substantially surrounding the inner core and comprising a thermoset
rubber; and at least one cover layer; wherein the inner core has a
compression deformation of from about 3.5 mm to about 4.1 mm, the
outer core layer has a compression deformation of from about 2.7 mm
to about 3.3 mm, and the outer core layer has a thickness of at
least 4.8 mm; and wherein the golf ball has a first initial
velocity measured at a club head speed of about 80 mph, the golf
ball has a second initial velocity measured at a club head speed of
about 125 mph, the initial velocities being otherwise measured
under the same conditions, and the difference between the second
initial velocity and the first initial velocity is at least about
85 mph.
[0009] In another aspect, this disclosure provides a golf ball
comprising: an inner core, the inner core being formed primarily of
at least one thermoplastic highly neutralized polymer, and the
inner core has a diameter of from about 20 mm to about 26 mm; an
outer core layer, the outer core substantially surrounding the
inner core and being made primarily of a thermoset rubber, and the
outer core layer has a thickness of from about 5 mm to about 9 mm;
an inner cover layer, the inner cover layer substantially
surrounding the outer core layer; and an outer cover layer, the
outer cover layer substantially surrounding the inner cover layer;
wherein the inner core has a compression deformation of from about
3.5 mm to about 4.1 mm, the outer core layer has a compression
deformation of from about 2.7 mm to about 3.3 mm, and a ratio of
the compression deformation of the inner core to the compression
deformation of the outer core layer is from about 1.1 to about 1.3;
the inner core having a first COR, the outer core having a second
COR, the second COR being greater than the first COR and having a
value of at least 0.8; and wherein the golf ball has a first
initial velocity measured at a club head speed of about 80 mph, the
golf ball has a second initial velocity measured at a club head
speed of about 125 mph, the initial velocities being otherwise
measured under the same conditions, and the difference between the
second initial velocity and the first initial velocity is at least
about 85 mph.
[0010] Finally, in a third aspect, this disclosure provides a golf
ball comprising an inner core, the inner core consisting
essentially of at least one highly neutralized polymer; an outer
core layer, the outer core substantially surrounding the inner core
and being made primarily of a thermoset rubber; and at least one
cover layer; wherein the golf ball has a first initial velocity
measured at a club head speed of about 80 mph, the golf ball has a
second initial velocity measured at a club head speed of about 125
mph, the initial velocities being otherwise measured under the same
conditions, and the difference between the second initial velocity
and the first initial velocity is at least about 85 mph.
[0011] Other systems, methods, features and advantages of the
invention will be, or will become, apparent to one of ordinary
skill in the art upon examination of the following figures and
detailed description. It is intended that all such additional
systems, methods, features and advantages be included within this
description and this summary, be within the scope of the invention,
and be protected by the following claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] The invention can be better understood with reference to the
following drawings and description. The components in the figures
are not necessarily to scale, emphasis instead being placed upon
illustrating the principles of the invention. Moreover, in the
figures, like reference numerals designate corresponding parts
throughout the different views.
[0013] FIG. 1 is a cut-away cross-sectional view of a first golf
ball in accordance with this disclosure.
[0014] FIG. 2 is a cut-away cross-sectional view of a second golf
ball in accordance with this disclosure.
DETAILED DESCRIPTION
[0015] Generally, this disclosure provides golf balls having an
inner core and an outer core that achieve favorable initial
velocity properties.
[0016] Except as otherwise discussed herein below, any golf ball
discussed herein may generally be any type of golf ball known in
the art. Namely, unless the present disclosure indicates to the
contrary, a golf ball may generally be of any construction
conventionally used for golf balls, and may be made of any of the
various materials known to be used in golf ball manufacturing.
Furthermore, it is understood that any feature disclosed herein
(including but not limited to various embodiments shown in the
FIGS. and various chemical formulas or mixtures) may be combined
with any other features disclosed here in any combination or
sub-combination, as may be desired.
[0017] FIG. 1 shows a first embodiment of a golf ball 100 in
accordance with this disclosure. Golf ball 100 is a three piece
golf ball, meaning that it includes three structural layers.
Namely, golf ball 100 includes inner core 110, outer core layer 120
substantially surrounding inner core 110, and cover layer 130
substantially surrounding outer core layer 120. Three piece golf
ball may also include other layers, such as paint layers or clear
coating layers that are generally considered ornamental finishing
layers rather than structural layers.
[0018] FIG. 2 shows a second embodiment of a golf ball 300 in
accordance with this disclosure. Golf ball 300 is a four piece golf
ball, meaning that it includes four structural layers. Namely, golf
ball 300 includes inner core 310, outer core layer 320
substantially surrounding inner core 310, inner cover layer 330
substantially surrounding outer core layer, and outer cover layer
340 substantially surrounding inner cover layer 330. As mentioned
above, four piece golf balls may also include other layers, such as
paint layers or clear coating layers that are generally considered
ornamental finishing layers rather than structural layers.
[0019] Golf balls in accordance with this disclosure generally
include at least two inner layers. Inner core 110 and outer core
layer 120, or inner core 310 and outer core layer 320, are
generally considered the inner layers. In addition to the three
piece golf ball 100 and four piece golf ball 300, golf balls in
accordance with this disclosure may also include one or more
additional layers not shown in the figures. For example, an
additional layer may be added between inner core 310 and outer
cover layer 340. For example, in other embodiments, an additional
cover layer may be inserted between inner cover layer 330 and outer
cover layer 340. In other embodiments, an additional core layer may
be inserted between inner core layer 310 and outer core layer 320.
Such additional layers made be added by a person having ordinary
skill in the art of golf ball manufacturing in accordance with
industry practice.
[0020] Although each of these structural layers is shown as being
spherical, in other embodiments the layers may have other
non-spherical shapes. FIGS. 1 and 2 are shown for illustrative
purposes, and are not necessarily to scale. Various aspects of a
golf ball in accordance with this disclosure may have relative
proportions and sizes other than are shown in FIGS. 1 and 2.
[0021] Each of the layers making up the golf ball construction
shown in the FIGS. 1 and 2, and their associated physical
properties, will be discussed herein below. As used herein, unless
otherwise stated, the following physical properties are defined and
measured as follows.
[0022] The term "compression deformation" as used herein indicates
the deformation amount of the ball under a force. Specifically, the
compression deformation value of a golf ball or some component of a
golf ball is defined as the difference between the amount of
deformation under a 10kg load and the amount of deformation under a
130 kg load.
[0023] The term "hardness" as used herein is measured generally in
accordance with ASTM D-2240. The hardness of a golf ball is
measured on the land area of a curved surface of a molded ball. The
hardness of a golf ball sub-component is measured on the curved
surface of the molded sub-component. The hardness of a material is
measured in accordance with ASTM D-2240 (on a plaque).
[0024] The term "coefficient of restitution" ("COR") as used herein
is measured according to the following method: a golf ball or golf
ball sub-component is fired by an air cannon at an initial velocity
of 40 m/sec, and a speed monitoring device is located over a
distance of 0.6 to 0.9 meters from the cannon. When the golf ball
or golf ball sub-component strikes a steel plate positioned about
1.2 meters away from the air cannon, the golf ball or golf ball
sub-component rebounds through the speed-monitoring device. The COR
is the return velocity divided by the initial velocity. All COR
values discussed herein are measured at an initial velocity of 40
m/sec unless otherwise indicated.
[0025] The term "flexural modulus" as used herein is the
measurement of a material in accordance with ASTM D-790.
[0026] As used herein, a polymer composition "comprises" a specific
material if the composition includes at least a non-trivial,
measureable, amount of that type of material. In contrast, a
polymer composition "consists essentially of" a specific type of
material if no other polymeric molecules are present in mixture
with the material. Polymer compositions commonly include additives,
fillers, unreacted monomers and oligomers, and other trace
non-polymeric ingredients, which are not necessarily excluded by
"consisting essentially of" language. A component is "formed
primarily of" a polymer composition when that polymer composition
is the main polymeric ingredient, making up at least 50.1% of the
component.
[0027] The Inner Core Layer.
[0028] In the present disclosure, the inner core refers to an inner
core such as inner core 110 or inner core 310. The inner core is
the innermost central structural component in the golf ball, and
includes golf ball center 260 (or golf ball center 460). Generally,
the inner core may be formed primarily of a thermoplastic resin,
instead of being formed of a thermoset rubber composition as in
conventional golf balls. The thermoplastic resin, while not subject
to any particular limitation, is exemplified by nylons,
polyarylates, ionomer resins, a highly neutralized ionomeric resin
or highly neutralized polymers (HNP's), polypropylene resins,
polyurethane based thermoplastic elastomers and polyester-based
thermoplastic elastomers. Commercial products such as Surlyn AD8512
(an ionomer resin available from DuPont), Himilan 1706 and Himilan
1707 (both ionomer resins available from DuPont-Mitsui
Polychemicals), HPF resins (highly neutralized polymers from
Dupont), Rilsan BMNO (a nylon resin available from Arkema) and
U-polymer U-8000 (a polyarylate resin available from Unitika) may
be used to form the inner core.
[0029] In particular embodiments, the thermoplastic resin may be
highly neutralized acid polymers (HNPs). Suitable highly
neutralized acid polymers include, but are not limited to, HPF
resins such as HPF1000, HPF2000, HPF AD1024, HPF AD1027, HPF
AD1030, HPF AD1035, HPF AD 1040, all produced by E. I. Dupont de
Nemours and Company.
[0030] The acid moieties of the HNP's, typically ethylene-based
ionomers, may be neutralized to greater than about 70%, or greater
than about 90%, or near 100%, or to 100%. The HNP's may be also
blended with a second polymer component, which, if containing an
acid group, may be neutralized in a conventional manner, by the
organic fatty acids, or by both. The second polymer component,
which may be partially or fully neutralized, may comprise ionomeric
copolymers and terpolymers, ionomer precursors, thermoplastics,
polyamides, polycarbonates, polyesters, polyurethanes, polyureas,
thermoplastic elastomers, polybutadiene rubber, balata,
metallocene-catalyzed polymers (grafted and non-grafted),
single-site polymers, high-crystalline acid polymers, cationic
ionomers, and the like. HNP polymers may typically have a material
hardness (plaque hardness) of between about 20 and about 80 Shore
D, and a flexural modulus of between about 3,000 psi and about
200,000 psi.
[0031] In one embodiment of the present disclosure, the HNP's may
be ionomers and/or their acid precursors that are neutralized,
either fully or partially, with organic acid copolymers or the
salts thereof. The acid copolymers are preferably .alpha.-olefin,
such as ethylene, C.sub.3-8.alpha.,.beta.-ethylenically unsaturated
carboxylic acid, such as acrylic and methacrylic acid, copolymers.
They may optionally contain a softening monomer, such as alkyl
acrylate and alkyl methacrylate, wherein the alkyl groups have from
1 to 8 carbon atoms.
[0032] The acid copolymers may be described as E/X/Y copolymers
where E is ethylene, X is an .alpha.,.beta.-ethylenically
unsaturated carboxylic acid, and Y is a softening comonomer. In a
preferred embodiment, X may be acrylic or methacrylic acid and Y
may be a C.sub.1-8 alkyl acrylate or methacrylate ester. X may be
present in an amount from about 1 to about 35 weight percent of the
polymer, or from about 5 to about 30 weight percent of the polymer,
or from about 10 to about 20 weight percent of the polymer. Y may
be present in an amount from about 0 to about 50 weight percent of
the polymer, or from about 5 to about 25 weight percent of the
polymer, or from about 10 to about 20 weight percent of the
polymer.
[0033] Specific acid-containing ethylene copolymers include, but
are not limited to, ethylene/acrylic acid/n-butyl acrylate,
ethylene/methacrylic acid/n-butyl acrylate, ethylene/methacrylic
acid/iso-butyl acrylate, ethylene/acrylic acid/iso-butyl acrylate,
ethylene/methacrylic acid/n-butyl methacrylate, ethylene/acrylic
acid/methyl methacrylate, ethylene/acrylic acid/methyl acrylate,
ethylene/methacrylic acid/methyl acrylate, ethylene/methacrylic
acid/methyl methacrylate, and ethylene/acrylic acid/n-butyl
methacrylate. Preferred acid-containing ethylene copolymers
include, ethylene/methacrylic acid/n-butyl acrylate,
ethylene/acrylic acid/n-butyl acrylate, ethylene/methacrylic
acid/methyl acrylate, ethylene/acrylic acid/ethyl acrylate,
ethylene/methacrylic acid/ethyl acrylate, and ethylene/acrylic
acid/methyl acrylate copolymers. In some embodiments, the
acid-containing ethylene copolymers are ethylene/(meth)acrylic
acid/n-butyl, acrylate, ethylene/(meth)acrylic acid/ethyl acrylate,
and ethylene/(meth)acrylic acid/methyl acrylate copolymers. As the
skilled practitioner recognizes, (meth)acrylic acid means
methacrylic acid, acrylic acid, or a blend thereof.
[0034] Ionomers are typically neutralized with a metal cation, such
as Li, Na, Mg, or Zn. It has been found that by adding sufficient
organic acid or salt of organic acid, along with a suitable base,
to the acid copolymer or ionomer, the ionomer may be neutralized
without losing processability to a level much greater than for a
metal cation alone. In some embodiments, the acid moieties may be
neutralized greater than about 80%, or from 90-100%, or about 100%
without losing processability. This may be accomplished by
melt-blending an ethylene/.alpha.,.beta.-ethylenically unsaturated
carboxylic acid copolymer, for example, with an organic acid or a
salt of organic acid, and adding a sufficient amount of a cation
source to increase the level of neutralization of all the acid
moieties (including those in the acid copolymer and in the organic
acid) to greater than 90%, or up to 100%.
[0035] The organic acids of the present disclosure may be
aliphatic, mono- or multi-functional (saturated, unsaturated, or
multi-unsaturated) organic acids. Salts of these organic acids may
also be used. The salts of organic acids may include the salts of
barium, lithium, sodium, zinc, bismuth, chromium, cobalt, copper,
potassium, strontium, titanium, tungsten, magnesium, cesium, iron,
nickel, silver, aluminum, tin, or calcium, salts of fatty acids,
particularly stearic, behenic, erucic, oleic, and linoleic acid, or
dimerized derivatives thereof. In some embodiments, the organic
acids and salts may be relatively non-migratory (they do not bloom
to the surface of the polymer under ambient temperatures) and
non-volatile (they do not volatilize at temperatures required for
melt-blending).
[0036] In the present disclosure, the inner core layer may have a
diameter of from 20 mm to 30 mm, or from 20 mm to 26 mm, or from 21
mm to 30 mm, or from 21 mm to 25 mm, or from 24 mm to 28 mm. FIG. 1
shows radius 210 of inner core 110, and FIG. 2 shows radius 410 of
inner core 310. Radius 210 or radius 410 may therefore have a value
of from about 10 mm to about 15 mm.
[0037] In some embodiments, the inner core layer may comprise a
blend of two highly neutralized acid polymers. Such blends may be
used to finely adjust the physical properties of the inner core.
For example, the inner core layer may comprise a first highly
neutralized acid polymer and a second highly neutralized acid
polymer. The two highly neutralized acid polymers may be dry
blended or be compounded in an extruder. In one embodiment, the
ratio of the first highly neutralized acid polymer to the second
highly neutralized acid polymer is from 20:80 to 80:20; in another
embodiment, the ratio is from 30:70 to 70:30; in another
embodiment, the ratio is from 40:60 to 60:40; in still another
embodiment, the ratio is 50:50.
[0038] The method used to obtain the inner core layer may be either
a compression molding or injection molding process, although
production by an injection molding process is preferred. In the
injection molding process, the temperature of the injection molding
machine is controlled between 195.degree. C. to 225.degree. C.
[0039] In some embodiments, the density of the inner core layer may
be from about 0.85 g/cm.sup.3 to about 1.1 g/cm.sup.3. In some
embodiments, the density of the inner core layer may be from about
0.9 g/cm.sup.3 to about 1.1 g/cm.sup.3.
[0040] The inner core layer of the present disclosure may have a
high resilience. The high resilience inner core layer may
contribute to a good flight performance of the golf ball. In the
present disclosure, the inner core layer may have a COR value of at
least 0.79. In some embodiment, the inner core layer has a COR
value of from 0.79 to 0.89 or from 0.79 to 0.85.
[0041] To reduce excess spin, the inner core may have a compression
deformation value in a range of from about 3.5 mm to about 4.1 mm.
The inner core may have a surface Shore D hardness of from 45 to
55. To have a stable performance, the inner core layer may have a
Shore D cross-sectional hardness of from 45 to 55 at any single
point on a cross-section obtained by cutting the inner core layer
in half, and may have a Shore D cross-sectional hardness difference
between any two points on the cross-section of within .+-.6, and in
some embodiment, the difference between any two points on the
cross-section may be within .+-.3.
[0042] The Outer Core Layer.
[0043] The outer core layer in the present disclosure generally
refers to an outer core such as outer core 120 shown in FIG. 1, or
outer core 320 shown in FIG. 2. The outer core layer may be formed
of a compression-molded thermoset rubber composition composed of
polybutadiene as the base rubber. Here, the polybutadiene has a
cis-1,4 bond content of at least 60%, preferably at least 80%, more
preferably at least 90%, and most preferably at least 95%.
[0044] It is recommended that the polybutadiene have a Mooney
viscosity (ML1+4 (100.degree. C.)) of at least 30, or at least 35,
or at least 40, or at least 50, or at least 52, but not more than
100, or not more than 80, or not more than 70, or not more than
60.
[0045] The term "Mooney viscosity" used herein refers to an
industrial indicator of viscosity as measured with a Mooney
viscometer, which is a type of rotary plastometer (JIS-K6300). The
unit symbol used is ML1+4 (100.degree. C.), where "M" stands for
Mooney viscosity, "L" stands for large rotor (L-type), "1+4"
denotes a pre-heating time of 1 minute and a rotor rotation time of
4 minutes, and "100.degree. C." indicates that measurement was
carried out at a temperature of 100.degree. C.
[0046] The molecular weight distribution Mw/Mn (where Mw stands for
the weight-average molecular weight, and Mn stands for the
number-average molecular weight) of the above polybutadiene may be
at least 2.0, or at least 2.2, or at least 2.4, or at least 2.6,
but not more than 6.0, or not more than 5.0, or not more than 4.0,
or not more than 3.4. Generally, if the Mw/Mn is too small, the
workability may worsen. On the other hand, if the Mw/Mn is too
large, the rebound of the golf ball may decrease.
[0047] The polybutadiene may be synthesized using a nickel or
cobalt catalyst, or may be synthesized using a rare-earth catalyst.
Synthesis with a rare-earth catalyst is especially preferred. A
known rare-earth catalyst may be used for this purpose. Examples
include catalysts obtained by combining a lanthanum series
rare-earth compound, an organoaluminum compound, an alumoxane, a
halogen-bearing compound and, in some embodiments, a Lewis
base.
[0048] In the present disclosure, the use of a neodymium catalyst
containing a neodymium compound as the lanthanum series rare-earth
compound may be used, because it enables a polybutadiene rubber
having a high 1,4-cis bond content and a low 1,2-vinyl bond content
to be obtained at a desirable polymerization activity.
[0049] When butadiene is polymerized in the presence of a
rare-earth catalyst, bulk polymerization or vapor-phase
polymerization may be carried out, with or without the use of a
solvent. The polymerization temperature may be set to generally
between -30.degree. C. and 150.degree. C., and preferably between
10.degree. C. and 100.degree. C.
[0050] Alternatively, the polybutadiene may be obtained by
polymerization using the rare-earth catalyst, followed by the
reaction of an active end on the polymer with a terminal modifier,
as known to a skilled practitioner.
[0051] The polybutadiene may be included in the rubber base in an
amount of at least 60 wt %, or at least 70 wt %, or at least 80 wt
%, or at least 90 wt %. The upper limit in the amount of
polybutadiene included may be 100 wt % or less, or 98 wt % or less,
or 95 wt % or less. When too little polybutadiene is included in
the rubber base, it may be difficult to obtain a golf ball having a
good rebound.
[0052] Rubbers other than the above-described polybutadiene may be
included and used together with the polybutadiene. Illustrative
examples of other rubbers include polybutadiene rubbers (BR),
styrene-butadiene rubbers (SBR), natural rubbers, polyisoprene
rubbers, and ethylene-propylene-diene rubbers (EPDM). These may be
used singly or as combinations of two or more thereof.
[0053] The outer core layer may be formed by compression molding a
rubber composition prepared by blending a base rubber with
ingredients typically included with a rubber compound in a golf
ball layer. Such ingredients include crosslinkers, such as
unsaturated carboxylic acids or a metal salt thereof; a peptizer
such as an organosulfur compound; a filler, particularly an
inorganic filler; and an antioxidant.
[0054] The unsaturated carboxylic acid may be exemplified by
acrylic acid, methacrylic acid, maleic acid and fumaric acid.
Acrylic acid and methacrylic acid may be used in particular
embodiments.
[0055] Metal salts of unsaturated carboxylic acids that may be used
include the zinc and magnesium salts of unsaturated fatty acids,
such as zinc methacrylate and zinc diacrylate. Zinc diacrylate may
be used in particular embodiments.
[0056] The amount of unsaturated carboxylic acid and/or metal salt
thereof included per 100 parts by weight of the base rubber may be
at least 20 parts by weight, or at least 22 parts by weight, or at
least 24 parts by weight, or at least 26 parts by weight, and may
be not more than 45 parts by weight, or not more than 40 parts by
weight. Including too much unsaturated carboxylic acid and/or metal
salt may result in excessive hardness, giving the ball an
unpleasant feel when played. On the other hand, including too
little unsaturated carboxylic acid and/or metal salt may result in
a decrease in the rebound.
[0057] An organosulfur compound may optionally be included. The
organosulfur compound can be advantageously used to impart an
excellent rebound. Thiophenols, thionaphthols, halogenated
thiophenols, and metal salts thereof are recommended for this
purpose. Illustrative examples include pentachlorothiophenol,
pentafluorothiophenol, pentabromothiophenol, p-chlorothiophenol,
and the zinc salt of pentachlorothiophenol; and
diphenylpolysulfides, dibenzylpolysulfides, dibenzoylpolysulfides,
dibenzothiazoylpolysulfides and dithiobenzoylpolysulfides having 2
to 4 sulfurs. Diphenyldisulfide and the zinc salt of
pentachlorothiophenol are especially preferred.
[0058] The amount of the organosulfur compound included per 100
parts by weight of the base rubber may be at least 0.1 part by
weight, or at least 0.2 part by weight, or at least 0.4 part by
weight, but may be not more than 5 parts by weight, or not more
than 4 parts by weight, or not more than 3 parts by weight, or not
more than 2 parts by weight. Including too much organosulfur
compound may excessively lower the hardness, whereas including too
little is unlikely to improve the rebound.
[0059] An inorganic filler may optionally be included in the base
rubber. The inorganic filler is exemplified by zinc oxide, barium
sulfate and calcium carbonate. The amount of the inorganic filler
included per 100 parts by weight of the base rubber may be at least
5 parts by weight, or at least 6 parts by weight, or at least 7
parts by weight, or at least 8 parts by weight, but may not be more
than 80 parts by weight, or not more than 60 parts by weight, or
not more than 40 parts by weight, or not more than 20 parts by
weight. Too much or too little inorganic filler may make it
difficult to achieve a suitable weight and a good rebound.
[0060] In some embodiments, the rubber composition may include as a
cross-linker an organic peroxide having a relatively short
half-life. Specifically, the half-life at 155.degree. C. of the
organic peroxide may be at least 5 seconds, or at least 10 seconds,
or at least 15 seconds. In some embodiments, the organic peroxide
may have a half-life at 155.degree. C. of not more than 120
seconds, or not more than 90 seconds, or not more than 60
seconds.
[0061] Examples of such organic peroxides include
1,1-bis(thexylperoxy) cyclohexane (trade name, Perhexa HC),
1-1-bis(t-hexylperoxy)-3,3,5-trimethylcyclohexane (trade name,
Perhexa TMH), 1,1-bis(t-butylperoxy)-3,3,5-trimethylcyclohexane
(trade name, Perhexa 3M) and 1-bis(t-butylperoxy)cyclohexane (trade
name, Perhexa C), all of which are available from NOF
Corporation.
[0062] To enable a good rebound and durability to be achieved, such
an organic peroxide may be included per 100 parts by weight of the
base rubber in an amount of at least 0.2 part by weight, or at
least 0.3 part by weight, but may be included in an amount of not
more than 3 parts by weight, or not more than 2 parts by weight, or
not more than 1.5 parts by weight, or not more than 1 part by
weight. If the amount included is too high, the rebound and
durability may decline. On the other hand, if the amount included
is too low, the time required for crosslinking may increase,
possibly resulting in a large decline in productivity and also a
large decline in compression.
[0063] An antioxidant may be included in the above rubber
composition, if desired in some embodiments. Illustrative examples
of the antioxidant include commercial products such as Nocrac NS-6
and Nocrac NS-30 (both available from Ouchi Shinko Chemical
Industry Co., Ltd.), and Yoshinox 425 (Yoshitomi Pharmaceutical
Industries, Ltd.). To achieve a good rebound and durability, the
antioxidant may be included in an amount per 100 parts by weight of
the base rubber of at least 0.03 part by weight, or at least 0.05
part by weight, but may be included in an amount of not more than
0.4 part by weight, or not more than 0.3 part by weight, or not
more than 0.2 part by weight.
[0064] Sulfur may also be added to the rubber composition as a
vulcanization agent in some embodiments. Such sulfur is exemplified
by the product manufactured by Tsurumi Chemical Industry Co., Ltd.
under the trade name Sulfur Z. The amount of sulfur included per
100 parts by weight of the base rubber may be at least 0.005 parts
by weight, or at least 0.01 parts by weight, but may be included in
an amount of not more than 0.5 part by weight, or not more than 0.4
part by weight, or not more than 0.1 part by weight. By adding
sulfur, the core hardness profile may be increased. However, adding
too much sulfur may result in undesirable effects during hot
molding, such as explosion of the rubber composition, or may
considerably lower the rebound.
[0065] The outer core layer may be made by a compression molding
process. Suitable vulcanization conditions include, a vulcanization
temperature of between 130.degree. C. and 190.degree. C., and a
vulcanization time of between 5 and 20 minutes. To obtain the
desired rubber crosslinked body for use as the core in the present
invention, the vulcanizing temperature may be at least 140.degree.
C.
[0066] When the outer core layer of the present disclosure is
produced by vulcanizing and curing the rubber composition in the
above-described way, advantageous use may be made of a method in
which the vulcanization step is divided into two stages: first, the
outer core layer material may be placed in an outer core
layer-forming mold and subjected to an initial vulcanization so as
to produce a pair of semi-vulcanized hemispherical cups, following
which a prefabricated inner core layer may be placed in one of the
hemispherical cups and covered by the other hemispherical cup, in
which state complete vulcanization is carried out.
[0067] The surface of the inner core layer placed in the
hemispherical cups may be roughened before the placement to
increase adhesion between the inner core layer and the outer core
layer. In some embodiments, the inner core layer's surface is
pre-coated with an adhesive (known to the skilled practitioner)
before placing the inner core layer in the hemispherical cups to
enhance the durability of the golf ball and enable a high
rebound.
[0068] To protect the inner core and to have a good resilience, the
outer core layer may have a thickness of at least 4.8 mm. In some
embodiments, the outer core layer may have a thickness of from 5 mm
to 9 mm. The outer core layer (with inner core layer inside) may
have a diameter of from 34 mm to 19 mm. To have a good flight
performance, the outer core layer (with the inner core layer
inside) may have a high coefficient of restitution of at least
0.800. In some embodiments, the outer core layer (with the inner
core layer inside) has the higher coefficient of restitution than
inner core layer alone, inner cover layer (with outer core and
inner core layer inside), or finished golf ball. Also, the outer
core layer preferably may have a compression deformation of from
about 2.7 mm to about 3.3 mm.
[0069] In the present disclosure, the ratio of the compression
deformation of the inner core layer (D inner) to that of the outer
core layer (D outer):(D inner)/(D outer) may be from about 1.1 to
about 1.3. If the ratio is less than about 1.1, the ball may be too
soft to have a good flight performance. However, if the number is
more than about 1.3, the hardness difference of the inner core
layer and outer core layer may be so big as to deteriorate the
durability of the golf ball.
[0070] The Cover Layer(s).
[0071] In the present disclosure, the cover layer may include one
or more structural cover layers. FIG. 1 shows a single cover layer
130, while FIG. 2 shows an inner cover layer 320 and an outer cover
layer 330. All such embodiments may be referred to herein as "the
cover layer." Generally, the cover layer is the outermost
structural component of the golf ball, and includes golf ball
surface 270 (or golf ball surface 470).
[0072] Generally, the material making up the cover layer is not
subject to any particular limitation; the cover may be formed using
a known cover material. Specific examples of the cover layer
material include known thermoplastic resins, ionomeric resins,
highly neutralized polymers, and thermoplastic and thermoset
polyurethanes. Alternatively, use may be made of
polyurethane-based, polyamide-based and polyester-based
thermoplastic elastomers. Conventional injection molding may be
advantageously used to form the cover layer.
[0073] When the cover layer used in the present disclosure is
relatively soft, the spin performance on approach shots may
improve, thus enabling increased controllability to be achieved.
Furthermore, in some situations, a relatively soft cover layer
might also enable longer shot distance. When the cover layer is
relatively hard, in addition to a distance-increasing effect, an
even lower spin rate may be achieved, enabling the distance to be
substantially improved.
[0074] In cases where the cover layer used in the disclosure is
formed to be relatively soft, the material making up the cover
layer may be an ionomeric resin, a highly neutralized ionomeric
resin composition, a polyurethane based thermoplastic elastomer, or
a polyester-based thermoplastic elastomer.
[0075] When the cover layer is composed of a single layer, such as
cover layer 130 shown in FIG. 1, the cover layer thickness 230 may
be at least about 0.5 mm, or at least about 0.6 mm, or at least
about 0.7 mm, or at least 0.8 mm, but not more than 2.0 mm.
Thickness 230 may also be not more than about 1.7 mm, or not more
than about 1.4 mm, or not more than about 1.2 mm. Also, the cover
hardness, expressed as the Shore D hardness, may be at least 35, or
at least 45, or at least 50, or at least 55, but may be not more
than 60.
[0076] In some embodiments, as shown in FIG. 2, the cover layer may
comprise two or more layers. In such embodiments, outer cover layer
340 may be softer than inner cover layer 330. The hardness of inner
cover layer 330, expressed as the Shore D hardness, may be at least
about 55, or at least about 60, or at least about 65, but may be
not more than about 75. The hardness of outer cover layer 340 may
be from about 50 to about 60 in Shore D hardness. The material
Shore D hardness of the outer cover layer (as measured on a plaque)
may be less than 40.
[0077] In the present disclosure, inner cover layer 330 may have a
thickness 430 of less than 2 mm. In some embodiments, inner cover
layer 330 may have a thickness 430 of less than 1.5 mm. In some
embodiments, inner cover layer 330 may have a thickness 430 of less
than 1 mm. Thickness 430 of inner cover layer 330 may also be at
least about 0.5 mm, or at least about 0.7 mm, or at least about 0.9
mm, or at least about 1.1 mm.
[0078] While inner cover layer 330 may be relatively thin, outer
cover layer 340 may have a thickness 440 of from about 0.8 mm to
about 2 mm. In some embodiments, outer cover layer 340 may have a
thickness 440 of from about 1.0 mm to about 2.0 mm. Outer cover
layer 340 may have a thickness 440 which is greater than thickness
430 of inner cover layer 330.
[0079] In some embodiments, the cover layer or outer cover layer
340 may comprise a crosslinked thermoplastic polyurethane elastomer
including crosslinks formed from allyl ether side groups, and said
crosslinked thermoplastic polyurethane elastomer is a reaction
product formed from reacting an organic isocyanate with a mixture
of the following reactants:
[0080] (a) an unsaturated diol of formula (1):
##STR00001##
[0081] in which R1 may be any substituted or unsubstituted alkyl,
substituted or unsubstituted aryl, substituted or unsubstituted
alkyl-aryl group, substituted or unsubstituted ether group,
substituted or unsubstituted ester group, any combination of the
above groups, or H, and may optionally include an unsaturated bond
in any main chain or side chain of any group; R.sup.2 may be any
suitable substituted or unsubstituted alkyl, substituted or
unsubstituted aryl, substituted or unsubstituted alkyl-aryl group,
substituted or unsubstituted ether group, substituted or
unsubstituted ester group, or a continuation of the single bond,
and R.sup.2 includes an allyl group; and x and y are integers
independently having any value from 1 to 10
[0082] (b) a chain extender, having at least two reaction sites
with isocyanates and having a molecular weight of less than about
450;
[0083] (c) a long chain polyol having a molecular weight of between
about 500 and about 4,000; and
[0084] (d) a sufficient amount of free radical initiator, so as to
be capable of generating free radicals that induce crosslinking
structures in the hard segments by free radical initiation.
[0085] In specific embodiments, the unsaturated diol may include an
allyl ether group as the side chain. For example, the unsaturated
diol may be represented by formula (2) shown below:
##STR00002##
in which R is a substituted or unsubstituted alkyl group, and x and
y are integers independently having values of 1 to 4. In particular
embodiments, x and y may both have values of 1, 2, 3 or 4. In other
embodiments, x and y may each have different values from 1 to
4.
[0086] In some embodiments, the unsaturated diol of formula (1) or
formula (2) may be trimethylolpropane monoallylether.
[0087] Crosslinked thermoplastic polyurethanes are further
disclosed in U.S. patent application Ser. No. 12/827,360 to
Chien-Hsin Chou et al. entitled "Golf Balls Including Crosslinked
Thermoplastic Polyurethane", and filed on Jun. 30, 2010.
Crosslinked thermoplastic polyurethane cover layers are also
disclosed in U.S. patent application Ser. No. 13/193,289 to
Chien-Hsin Chou et al. entitled "Golf Balls Including A Crosslinked
Thermoplastic Polyurethane Cover Layer Having Improved Scuff
Resistance", and filed on Jul. 28, 2011. Crosslinked thermoplastic
polyurethane cover layers are also disclosed in U.S. patent
application Ser. No. 13/193,391 to Chien-Hsin Chou et al. entitled
"Four-Piece Golf Balls Including a Crosslinked Thermoplastic
Polyurethane Cover Layer." The disclosures of these three
co-pending applications are hereby incorporated by reference in its
entirety.
[0088] The cover layer or outer cover layer with the crosslinked
thermoplastic polyurethane elastomer may have a flexural modulus of
less than about 1,000 psi, or less than about 800 psi, or less than
about 600 psi.
[0089] The Golf Ball
[0090] A golf ball in accordance with this disclosure, such as golf
ball 100 shown in FIG. 1 or golf ball 300 shown in FIG. 2, may have
various physical features and properties. For example, a golf ball
may have a diameter that accords with USGA standards. Namely, a
golf ball may have a diameter of not less than 42.67 mm (1.680
inches USGA standard), or in other embodiments the diameter may be
not more than 44 mm, or not more than 43.8 mm, or not more than
43.5 mm, or not more than 43 mm.
[0091] The golf ball may also have a compression deformation of at
least about 2.3 mm, or at least about 2.4 mm, or at least about 2.5
mm, or at least about 2.6 mm. The value of the compression
deformation may be not more than about 5.0 mm, or not more than
about 4.5 mm, or not more than about 4.0 mm, or not more than about
3.8 mm.
[0092] A golf ball in accordance with the present disclosure may
have a COR of 0.80 or less, or 0.79 or less, or 0.78 or less.
[0093] The golf ball may also have certain initial velocities, and
relationships among its initial velocities at different club head
speeds. Generally, the golf ball may have a first initial velocity
measured at a club head speed of about 80 mph, a second initial
velocity measured at a club head speed of about 125 mph but
otherwise under the same testing conditions, where the difference
between the second initial velocity and the first initial velocity
is at least about 85 mph.
[0094] In some embodiments, the initial velocity at certain club
head speeds may have advantageous values. For example, the initial
velocity of the golf ball when measured in response to a club head
speed of 80 mph may be at least 87 mph. In another example, the
initial velocity at a club head speed of 125 mph may be at least
173 mph. Such values may enable the golf ball to achieve desirable
longer shot distances. Further initial velocities are shown and
discussed in the Examples, below.
[0095] A golf ball in accordance with this disclosure may include a
resilient material, or any other feature, as described in U.S.
patent application Ser. No. 13/193,025 to Ichikawa, filed on Jul.
28, 2011 and entitled "Golf Ball Having a Resilient Material." The
disclose of this co-pending application is hereby incorporated by
reference in its entirety to the extent that the disclosure does
not conflict with the explicit teachings of the present
disclosure.
[0096] A golf ball in accordance with this disclosure may include
layers having certain flexural modulus and hardness values, or any
other feature, as described in U.S. patent application Ser. No.
13/193,025 to Chen-Tai Liu filed on Aug. 20, 2010, and entitle
"Golf Ball Having Layers with Specified Moduli and Hardnesses." The
disclose of this co-pending application is hereby incorporated by
reference in its entirety to the extent that the disclosure does
not conflict with the explicit teachings of the present
disclosure.
EXAMPLES
[0097] Manufacturing the Golf Ball: for examples of the present
disclosure, the inner core layer was made from a material selected
from Table 1; the outer core layer was made from a material
selected from Table 2; the inner cover layer was made from a
material selected from Table 3; and the outer cover layer was made
from a material selected from Table 4. The amount of the materials
listed in Tables 1, 2, 3 and 4 is shown in parts by weight (pbw) or
percentages by weight.
TABLE-US-00001 TABLE 1 Inner Core Layer Materials Resin: A HPF 2000
60 HPF AD 1035 40
[0098] HPF 2000 and HPF AD 1035 are trade names of ionomeric resins
by E. I. DuPont de
[0099] Nemours and Company.
TABLE-US-00002 TABLE 2 Outer Core Layer Rubber compound: B TAIPOL
.TM. BR0150 100 Zinc diacrylate 29 Zinc oxide 9 Barium sulfate 11
Peroxide 1
[0100] TAIPOL.TM. BR0150 is the trade name of a rubber produced by
Taiwan Synthetic Rubber Corp.
TABLE-US-00003 TABLE 3 Inner Cover Layer Material Resin: C Neothane
6303D 100
[0101] Neothane 6303D is the trade name of a thermoplastic
polyurethane produced by
[0102] Dongsung Highchem Co. LTD.
TABLE-US-00004 TABLE 4 Outer Cover Layer Materials D PTMEG (pbw)
100 BG (pbw) 15 TMPME (weight % to total components) 10% DCP
(weight % to total components) 0.5% MDI (pbw) 87.8
[0103] "PTMEG" is polytetramethylene ether glycol, having a number
average molecular weight of 2,000, and is commercially available
from Invista, under the trade name of Terathane.RTM. 2000. "BG" is
1,4-butanediol, commercially available from BASF and other
suppliers. "TMPME" is trimethylolpropane monoallylether,
commercially available from Perstorp Specialty Chemicals AB. "DCP"
is dicumyl peroxide, commercially available from LaPorte Chemicals
Ltd. Finally, "MDI" is diphenylmethane diisocyanate, commercially
available from Huntsman, under the trade name of Suprasec.RTM.
1100.
[0104] Outer cover material D was formed by mixing PTMEG, BG,
TMPME, DCP and MDI in the proportions shown. Specifically, these
materials were prepared by mixing the components in a high agitated
stir for 1 minute, starting at a temperature of about 70 degrees
Celsius, followed by a 10-hour post curing process at a temperature
of about 100 degrees Celsius. The post cured polyurethane
elastomers are ground into small chips.
[0105] From the above materials, golf balls were manufactured as
shown in Table 5. Generally, the golf balls were manufactured using
conventional compression molding and injection molding processes
known in the art of golf ball manufacturing.
TABLE-US-00005 TABLE 5 Golf Ball Construction Inner Core Layer
Material A Diameter (mm) 24 Surface Shore D Hardness 53 Compression
Deformation (mm) 3.5 COR 0.799 Outer Core Layer Material B
Thickness (mm) 7.25 Surface Shore D Hardness 59 Compression
Deformation (D 3.0 COR 0.803 Ratio (D.sub.inner)/(D.sub.outer) 1.17
Inner Cover Layer Material C Thickness (mm) 1.0 Surface Shore D
Hardness 69 COR 0.798 Outer Cover Layer Material D Thickness (mm)
1.1 Surface Shore D Hardness 54 Flexural Modulus(psi) 550 Ball COR
0.785
[0106] An initial velocity test of driver shot was conducted in the
following manner: a Nike SQ Dymo driver (loft: 10.5.degree.; shaft:
Diamana by Mitsubishi Rayon; flex: X; grip: golf pride) is fixed to
a swing robot manufactured by Miyamae Co., Ltd. and then swung at
different head speed from about 80 mph to about 125 mph. The
clubface was oriented for a square hit. The forward/backward tee
position was adjusted so that the tee was three inches in front of
the point in the downswing where the club was vertical. The height
of the tee and the toe-heel position of the club relative to the
tee were adjusted in order that the center of the impact mark was
centered toe to heel across the face. Specifically, the ball was
centered relative to the club face both toe-to-heel and
top-to-bottom. As used throughout the present specification, the
term "initial velocity" refers to a measurement under substantially
similar conditions: using a driver, and the golf ball being
centered on the club face both toe-to-heel and top-to-bottom.
[0107] Furthermore, each of the tests shown in Tables 6-9
(including, but not limited to, the initial velocity tests) were
conducted relative to a standard known golf ball, the Nike "One
Tour D." The "One Tour D" is a tour-level golf ball made and sold
by Nike Inc. that is widely commercially available. Namely, any
test that measures a golf ball in accordance with this disclosure
should first be calibrated to achieve the values as shown below for
the One Tour D under the conditions as noted. In this way, the
testing procedure can be standardized relative to a known golf
ball. The margin of error within any test is +/-1 mph, +/-1 degree
angle, and +/-150 rpm. Any value that is described as being "about"
or "substantially" a certain value may vary by these margin of
errors.
[0108] Initial velocity tests were done at 125 mph, 110 mph, 95
mph, and 80 mph. The results are shown in Tables 6-9 below.
[0109] The example was constructed in accordance with Table 5,
above. The comparative examples C1-04 are commercially available
golf balls. Specifically, the "Pro V1" is a tour-level golf ball
made and sold by Titleist, the "Tour (i)s" is a tour-level golf
ball made and sold by Callaway Golf, and the "One Tour" and "One
Tour D" are both tour-level golf balls made and sold by Nike Inc.
For each example and comparative example, six instances of each
golf ball were tested with the golf ball being aligned on the seam,
and six instances were tested with the golf ball being aligned on
the pole. These twelve data points were then averaged for each type
of golf ball to arrive at the data shown in Tables 6-9.
[0110] The golf balls as shown in the second column of Table 6 are
the same example and comparative examples E1 and C1-04 throughout
all tests. The weights and compressions shown in Table 6 are the
same through all of the tests, and are omitted from Tables 7-9 only
for convenience.
[0111] The following tests for driver shots show how exemplary golf
ball in accordance with this disclosure achieve a better initial
velocity performance when the head speed is very high.
TABLE-US-00006 TABLE 6 Golf ball Testing Data - Head Speed = 125
mph # Golf Ball Weight Compression Ball IV (mph) Back spin (rpm)
Launch angle .degree. Carry (yards) Total Distance (yards) E1
Example 1 45.72 2.55 174 2561 12.3 294 313 C1 One Tour D 45.57 2.86
171 2905 13.2 286 299 C2 Pro V1 45.83 2.66 173 3065 12.5 288 300 C3
Tour i(s) 45.94 2.58 171 3103 12.9 285 292 C4 One Tour 45.62 2.6
171 3375 12.3 283 292
TABLE-US-00007 TABLE 7 Golf ball Testing Data - Head Speed = 110
mph Ball Initial Back Launch Carry Total Distance Test # Velocity
(mph) spin (rpm) angle .degree. (yards) (yards) E1 160 2745 12.3
264 284 C1 159 2748 12.7 263 283 C2 159 2829 12.6 263 283 C3 157
2801 12.7 260 279 C4 160 3223 12.5 263 276
TABLE-US-00008 TABLE 8 Golf ball Testing Data - Head Speed = 95 mph
Ball Initial Back Launch Carry Total Distance Test # Velocity (mph)
spin (rpm) angle .degree. (yards) (yards) E1 116 2664 11.1 157 191
C1 117 2512 11.5 158 194 C2 116 2783 11.3 158 191 C3 117 2659 11.1
156 191 C4 116 2980 10.9 156 188
TABLE-US-00009 TABLE 9 Golf ball Testing Data - Head Speed = 80 mph
Ball Initial Back Launch Carry Total Distance Test # Velocity (mph)
spin (rpm) angle .degree. (yards) (yards) E1 88 2181 10.8 85 125 C1
90 2139 10.9 88 128 C2 88 2243 10.8 86 125 C3 88 2377 10.6 84 123
C4 89 2418 10.6 88 126
[0112] Table 10 shows how an exemplary ball in accordance with this
disclosure has a large difference between the initial velocity
under a high club head speed and the initial velocity under a low
club head speed. In particular, the difference between 125 mph and
80 mph is larger than any comparative example. Accordingly, the
slope of the function "initial velocity=function(club head speed)"
is steep.
TABLE-US-00010 TABLE 10 Change in Initial Velocities between
Different Club Head Speeds Club Head Speed .DELTA.: 95-80 110-80
125-80 Example 28 72 86 Nike One Tour D 27 69 81 Pro V1x 28 71 85
Tour i(s) 29 69 83 Nike One Tour 27 71 82
[0113] Therefore, a golf ball in accordance with this disclosure
may perform well at lower swing speeds (such as those achieved by
amateur golfers) by achieving an initial velocity that is
substantially similar to various comparative examples. Further, a
golf ball in accordance with this disclosure may also perform
better than a variety of comparative examples at higher swing
speeds (such as those achieved by professional golfers) by
achieving an increased initial velocity. Therefore, a golf ball in
accordance with this disclosure may be versatile enough to be
easily used by golfers having a wide range of abilities.
[0114] While various embodiments of the invention have been
described, the description is intended to be exemplary, rather than
limiting and it will be apparent to those of ordinary skill in the
art that many more embodiments and implementations are possible
that are within the scope of the invention. Accordingly, the
invention is not to be restricted except in light of the attached
claims and their equivalents. Also, various modifications and
changes may be made within the scope of the attached claims.
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