U.S. patent application number 17/748399 was filed with the patent office on 2022-09-01 for golf ball and method of making same.
This patent application is currently assigned to Acushnet Company. The applicant listed for this patent is Acushnet Company. Invention is credited to Edward Costa, Erin C. McDermott.
Application Number | 20220273989 17/748399 |
Document ID | / |
Family ID | 1000006348561 |
Filed Date | 2022-09-01 |
United States Patent
Application |
20220273989 |
Kind Code |
A1 |
Costa; Edward ; et
al. |
September 1, 2022 |
GOLF BALL AND METHOD OF MAKING SAME
Abstract
Golf ball comprising a core and a cover, wherein the core
includes between 2 and 20 smaller spheres that are surrounded by a
second core composition having at least one different physical
property than the composition(s) forming the smaller spheres. The
smaller spheres can be entirely surrounded by the second core
composition; or, at least two smaller adjacent spheres may each be
partially surrounded by the second core composition while also
being in partial contact with each other.
Inventors: |
Costa; Edward; (East
Providence, RI) ; McDermott; Erin C.; (Providence,
RI) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Acushnet Company |
Fairhaven |
MA |
US |
|
|
Assignee: |
Acushnet Company
Fairhaven
MA
|
Family ID: |
1000006348561 |
Appl. No.: |
17/748399 |
Filed: |
May 19, 2022 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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17188325 |
Mar 1, 2021 |
11338177 |
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17748399 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A63B 37/0054 20130101;
A63B 2102/32 20151001; A63B 37/0064 20130101; A63B 37/0056
20130101 |
International
Class: |
A63B 37/00 20060101
A63B037/00 |
Claims
1. A golf ball comprising: a cover; and a core surrounded by the
cover and defining a core center point, the core comprising: a
plurality of spheres formed from a first composition, each of the
plurality of spheres defining a sphere center point; and a second
composition, different from the first composition, surrounding the
plurality of spheres, the second composition formed in a shape
having a spherical outer surface that defines a plurality of
diameters through the core center point, wherein the second
composition occupies the core center point and at least one of the
plurality of diameters of the spherical outer surface follows a
linear path through the core that does not intersect any of the
plurality of spheres such that the linear path extends only through
the second composition.
2. The golf ball of claim 1, wherein the plurality of spheres are
arranged such that each of the sphere center points are equally
spaced from the core center point.
3. The golf ball of claim 1, wherein the plurality of spheres are
arranged such that all of the sphere center points are located in
the same plane.
4. The golf ball of claim 3, wherein the plurality of spheres are
arranged such that each of the sphere center points are equally
spaced from the core center point.
5. The golf ball of claim 1, wherein the plurality of spheres are
arranged such that a first subset of the sphere center points are
located in a first plane and a second subset of the sphere center
points are located in a second plane, wherein all of the sphere
center points are in the first subset or the second subset.
6. The golf ball of claim 5, wherein the first plane is parallel to
the second plane.
7. The golf ball of claim 5, wherein the plurality of spheres are
arranged in a tetrahedron shape.
8. The golf ball of claim 7, wherein the tetrahedron shape defines
a tetrahedron center point, wherein the tetrahedron center point is
located at the core center point.
9. The golf ball of claim 1, wherein the plurality of spheres are
arranged in a shape having at least one axis of rotational
symmetry.
10. The golf ball of claim 9, wherein the plurality of spheres are
arranged in a shape having four axes of rotational symmetry.
11. The golf ball of claim 1, wherein each of the plurality of
spheres is positioned in contact with at least one other sphere of
the plurality of spheres.
12. The golf ball of claim 11, wherein each of the plurality of
spheres is positioned in contact with two other spheres of the
plurality of spheres such that the first composition is formed in a
continuous that band extends circumferentially around the core
center point.
13. The golf ball of claim 1, wherein the first composition has a
first hardness and the second composition has a second hardness,
wherein the first hardness is less that the second hardness.
14. The golf ball of claim 13, wherein each of the plurality of
spheres have a diameter of between 0.3 in. and 0.75 in.
15. A golf ball comprising: a cover; and a core surrounded by the
cover and defining a core center point, the core comprising: a
plurality of spheres formed from a first composition; and a second
composition, different from the first composition, surrounding the
plurality of spheres, wherein the first composition has a first
hardness and the second composition has a second hardness, wherein
the first hardness is less that the second hardness, wherein the
second composition occupies the core center point.
16. The golf ball of claim 15, wherein each of the plurality of
spheres has a diameter of between 0.3 in. and 0.75 in.
17. The golf ball of claim 15, wherein the second hardness is
greater than the first hardness by about 12-22 Shore C hardness
points.
18. The golf ball of claim 15, wherein the second hardness is
greater than the first hardness by at least 15 Shore C hardness
points.
19. The golf ball of claim 15, wherein the plurality of spheres are
arranged in a shape having at least four axes of rotational
symmetry.
20. The golf ball of claim 15, wherein each of the plurality of
spheres is positioned in contact with at least one other sphere of
the plurality of spheres.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present application is a continuation of U.S. patent
application Ser. No. 17/188,325, filed Mar. 1, 2021, the entire
disclosure of which is hereby incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The field of the invention broadly comprises golf balls
incorporating cores having regions of physical property differences
therein; and methods of making same.
BACKGROUND OF THE INVENTION
[0003] Today, both professional and amateur golfers alike use
multi-piece, solid golf balls. For example, in a two-piece solid
golf ball construction, a solid core is typically protected by a
cover. The core is often made of a natural or synthetic rubber such
as polybutadiene, styrene butadiene, or polyisoprene. In turn, the
cover may be formed from of a variety of materials such as ethylene
acid copolymer ionomers, polyamides, polyesters, polyurethanes,
and/or polyureas.
[0004] Three-piece, four-piece, and even five-piece golf balls
became more popular with the development of manufacturing
technologies for efficiently producing same. Multi-layered cores
may be comprised, for example, of an inner core containing a
relatively soft and resilient material, surrounded by an outer core
layer made of a harder and more rigid material. This "dual-core"
sub-assembly is then encapsulated by at least one layer such as
single or multi-layered cover layer, and optionally one or more
intermediate layers to complete the golf ball construction.
[0005] Meanwhile, golf ball manufacturers pre-select the materials
for each layer to target and impart desirable improved golf ball
playing/performance properties/characteristics cost effectively.
Currently, a broad range of options are available for strategically
incorporating and coordinating layers within each golf ball
construction. In multi-layered golf balls, each of the core,
intermediate layer and cover can be single or multi-layered, and
properties such as hardness, compression, resilience, specific
gravity, core diameter, intermediate layer thickness and cover
thickness can be preselected and coordinated to target play
characteristics such as spin, initial velocity and feel of the
resulting golf ball.
[0006] In particular, the core is an important part of any golf
ball because it acts as an engine or spring for the golf ball.
Therefore, golf ball manufacturers continue to improve a core's
construction and composition, which are key factors in targeting
the resiliency and rebounding performance of the ball.
[0007] In this regard, golf ball manufacturers have previously
adjusted/modified core properties by dispersing processing aids,
fillers, and/or particulates throughout the entire core
composition. Additionally, hardness gradients have been created in
cores by adjusting the cure profile of the core composition so that
core hardness can increase and/or decrease from the core's
geometric center radially outward toward its outer surface. In yet
other golf ball constructions, property gradients have been created
by exposing the core's outer surface to a surface penetrating
solution/composition which modifies the properties of the outer
surface relative to the remaining portion of the core that is not
exposed to the surface penetrating solution/composition. In still
other golf ball constructions, core inserts have been disclosed
having a hub with and a plurality of outer elements connected to
the hub. In these constructions, the hub is a centralized element
by which the outer elements are inter-connected at the core
center.
[0008] However, it is important that modifications to the core do
not negatively impact flight symmetry. Flight symmetry is achieved
when a golf ball flies at substantially the same height and
distance, and remains in flight for substantially the same period
of time, regardless of how it is placed on the tee. Without flight
symmetry, "hooking" or "slicing" can occur when the golf ball is in
flight after being struck by a golf club face. An unbalanced core
can also cause the golf ball to roll out of alignment during
putting on the course.
[0009] Accordingly, there is a need for unique golf balls
incorporating novel core constructions that don't sacrifice golf
ball flight symmetry and/or putting trajectory. Golf balls of the
invention and methods of making same address and fulfill this
need.
SUMMARY OF THE INVENTION
[0010] Advantageously, a golf ball of the invention incorporates a
core comprising a first material that is formed, by a method such
as injection molding, compression molding and/or casting, into a
plurality of spheres that have at least one physical property that
is different than at least one physical property of a second core
composition that surrounds the plurality spheres within the core.
Thus, the second core composition forms a spherical core member
with the plurality of smaller spheres formed from the first core
composition dispersed therein. These smaller spheres are spaced
from each other and suspended within the surrounding second core
composition such that golf ball flight symmetry is achieved and the
golf ball does not roll out of alignment during putting on the
course.
[0011] In one embodiment, a golf ball of the invention comprises a
core and a cover, wherein the core has a core center that comprises
between 2 and 20 smaller spheres suspended therein. The smaller
spheres have diameters of 0.01 to 0.75 inches and are formed of a
first rubber composition. The smaller spheres are surrounded by a
second core composition having at least one different physical
property than the first rubber composition.
[0012] In one embodiment, a plurality of the smaller spheres have
sphere centers that are equally spaced from the core center.
[0013] In another embodiment, the smaller spheres have sphere
centers that are equally spaced from the core center.
[0014] In a specific embodiment a plurality of the smaller spheres
have diameters of between 0.2 inches and 0.5 inches.
[0015] In a particular embodiment, an entire outer surface of each
smaller sphere is surrounded by the second core composition.
[0016] In a different embodiment, the smaller spheres abut at least
one adjacent smaller sphere, and more preferably, the smaller
spheres abut at least two adjacent smaller spheres.
[0017] In one embodiment, the second core composition is selected
from the group of thermoset rubber compositions and/or
thermoplastic compositions.
[0018] In a specific embodiment, the smaller spheres have a
diameter that is equal to each other and have a mass that is equal
to each other.
[0019] In a different embodiment, a first portion of the smaller
spheres have a first diameter and a second portion of the smaller
spheres have a second diameter that is less than the first
diameter.
[0020] In another embodiment, a golf ball of the invention
comprises a core and a cover, wherein the core has a core center
and comprises between 2 and 20 smaller spheres disposed therein.
The plurality of smaller spheres have sphere centers and are
dispersed substantially symmetrically about, but not concentric
with, the core center.
[0021] In a specific embodiment, the smaller spheres are formed of
a first core composition that has a physical property having a
first value and the surrounding portion of the core is comprised of
a second core composition that has the physical property having a
second value that is different than the first value. For example,
the physical property may be selected from the group of hardness,
compression, coefficient of restitution, and/or specific gravity.
In a specific embodiment, the smaller spheres have a diameter and
the smaller sphere centers are spaced from the core center by a
distance greater than 1/2 the diameter. In one particular
embodiment, the first core composition is selected from the group
of thermoset compositions, such as rubber compositions,
thermoplastic compositions, metal-based or metal-containing
compositions, and/or blends thereof. Preferably, the second core
composition is selected from the group of thermoset compositions,
such as rubber compositions, thermoplastic compositions,
metal-containing compositions, and/or blends thereof.
[0022] A plurality of the smaller spheres are preferably solid or
foamed.
[0023] Each of a plurality of the smaller spheres may have a hollow
portion that is encased by the first core composition.
[0024] The invention also relates to a method of making a golf ball
comprising the steps of: i) forming a spherical core by: a) forming
between 2 and 20 smaller spheres, each having a diameter of from
0.01 inches to 0.75 inches by injection molding, compression
molding or casting a first rubber composition; and b) molding a
second core composition that has at least one different physical
property than the first rubber composition about each of the
smaller spheres such that the smaller spheres are uniformly
dispersed therein; and ii) forming at least a cover about the
spherical core. In this method, an entire outer surface of each
smaller sphere may be surrounded by the second core composition.
Alternatively, an outer surface of at least one smaller sphere may
abut an outer surface of at least one other smaller sphere, and
therefore, be partially surrounded by the second core
composition.
[0025] Preferably, the smaller spheres are all formed of the same
first rubber composition. Alternatively, some portion of the
smaller spheres may be formed of a different rubber or
thermoplastic composition. However, both of these compositions
forming the smaller spheres should be different than the
composition that forms the surrounding portion of the core.
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] These and other aspects of the present invention as set
forth in the appended claims may be more fully understood with
reference to, but not limited by, following detailed description in
connection with the accompanying drawings in which like numerals
refer to like elements of the inventive golf ball and method of
making same:
[0027] FIG. 1A is a perspective view of a golf ball of the
invention according to one embodiment;
[0028] FIG. 1B is a cross-sectional view of the golf ball of the
invention according to the embodiment depicted in FIG. 1A;
[0029] FIG. 2A is a perspective view of a golf ball of the
invention according to another embodiment;
[0030] FIG. 2B is a cross-sectional view of a golf ball of the
invention according to the embodiment depicted in FIG. 2A; and
[0031] FIG. 3 is a cross-sectional view of a golf ball of the
invention according to yet another embodiment.
DETAILED DESCRIPTION
[0032] A golf ball of the invention incorporates a core comprising
at least two pre-formed injection molded, compression molded and/or
cast volumes of material such as a sphere; each having at least one
different physical property than at least one physical property of
a second core composition that surrounds the volumes of material.
The volumes of material are spaced within a surrounding second core
composition of the core before the surrounding second core
composition is fully cured such that flight symmetry is achieved
and the golf ball does not roll out of alignment during putting on
the course.
[0033] Accordingly, in golf balls of the invention, smaller spheres
may be oriented in any geometry symmetrically about, but not
intersecting, the core center. In many embodiments, the entire
outer surface of each smaller sphere is surrounded by (and in
contact with) a second core composition. In some embodiments, a
portion of at least one smaller sphere may abut/contact a portion
of an adjacent smaller sphere so that that the surrounding second
core composition is in contact with a portion of the outer surface
of each of those smaller spheres.
[0034] The invention may be more fully understood with reference
to, but not limited by, FIGS. 1A, 1B, 2A, 2B and 3. Referring to
FIG. 1A, golf ball 2 comprises core 4 and cover 6. Core 4 has a
core center 8 and four smaller spheres 10 that are disposed about
core center 8 and are comprised of a first composition. Each
smaller sphere 10 has a sphere center 12, is tangent to two other
spheres 10, and is surrounded by second core composition 14 which
has at least one different physical property than the first core
composition. The four smaller spheres 10 are collectively located
in the same plane 16 that is perpendicular to polar axis 18 which
intersects core center 8.
[0035] Meanwhile, FIG. 1B is a cross-sectional view of a golf ball
of the invention according to the embodiment depicted in FIG. 1A.
In FIG. 1B, first smaller spheres 10 have diameters D.sub.1,
D.sub.2, D.sub.3, and D.sub.4, wherein
D.sub.1=D.sub.2=D.sub.3=D.sub.4. Additionally, smaller spheres 10
have sphere centers C1, C2, C3, and C4, respectively (which
correspond to sphere centers 12 of FIG. 1A), and each smaller
sphere 10 is tangent to two other spheres 10. Sphere centers C1,
C2, C3, and C4 of smaller spheres 10 are located distances X.sub.1,
X.sub.2, X.sub.3, and X.sub.4, respectively, from core center 8. In
this embodiment. X.sub.1=X.sub.2=X.sub.3=X.sub.4; and X.sub.1 is
greater than 1/2 D.sub.1.
[0036] Referring to FIG. 2A, golf ball 5 comprises core 4 and cover
6. Core 4 has a core center 8 and four smaller spheres 10 that are
comprised of a first core composition. Each smaller sphere 10 has a
sphere center 12 and is surrounded by second core composition 14
which has at least one different physical property than the first
core composition.
[0037] In golf ball 5, four smaller spheres 10 are oriented in a
tetrahedron geometry about core center 8 and therefore have 4 axes
of rotational symmetry, with each sphere 10 being tangent to two
other small spheres 10. The rotational axes pass through each
smaller sphere center 12 as well as through a corresponding
midpoint on an opposite face 20a, 20b, 20c or 20d.
[0038] Meanwhile, FIG. 2B is a cross-sectional view of a golf ball
of the invention according to the embodiment depicted in FIG.
2A.
[0039] Additionally, in FIG. 3, golf ball 7 comprises core 4 and
cover 6. Core 4 has a core center 8 and four smaller spheres 10
that are disposed about core center 8 and are comprised of a first
core composition. First smaller spheres 10 have sphere centers
C.sub.1, C.sub.2, C.sub.3, and C.sub.4, respectively, and each
smaller sphere 10 is tangent to two other spheres 10. As in FIG.
1B, first smaller spheres 10 have diameters D.sub.1, D.sub.2,
D.sub.3, and D.sub.4, wherein D.sub.1=D.sub.2=D.sub.3=D.sub.4; and
smaller spheres 10 are located distances X.sub.1, X.sub.2, X.sub.3,
X.sub.4, respectively, from core center 8, wherein
X.sub.1=X.sub.2=X.sub.3=X.sub.4; and X.sub.1 is greater than 1/2
D.sub.1.
[0040] Moreover, in FIG. 3, second smaller spheres 22 surround and
are disposed between adjacent smaller spheres 10 and are comprised
of a third core composition. Second smaller spheres 22 have sphere
centers C.sub.5, C.sub.6, C.sub.7, and C.sub.8, respectively, and
have diameters D.sub.5, D.sub.6, D.sub.7, and D.sub.8,
respectively, wherein D.sub.5=D.sub.6=D.sub.7=D.sub.8. Second
smaller spheres 22 are located distances X.sub.5, X.sub.6, X.sub.7,
and X.sub.8, respectively, from core center 8, wherein
X.sub.5=X.sub.6=X.sub.7=X.sub.8; and D.sub.5 is less than D.sub.1;
and X.sub.5 is greater than X.sub.1.
[0041] Meanwhile, each of smaller spheres 10 and smaller spheres 22
are surrounded by second core composition 14 that has at least one
different physical property than at least one physical property of
the first core composition and the third core composition. In
preferred embodiments, the first core composition and third
composition have at least one different physical property. However,
embodiments are also envisioned wherein the first core composition
is the same as the third core composition.
[0042] Advantageously, in a golf ball of the invention, smaller
spheres 10 may be spaced within the second core composition without
intersecting center 8. Instead, each smaller sphere may be entirely
surrounded by and suspended/secured within the surrounding second
core composition.
[0043] In other embodiments, at least one smaller sphere may
abut/contact an adjacent smaller sphere so that each smaller sphere
is partially surrounded by the surrounding second core composition
and partially contacting the adjacent smaller sphere.
[0044] In yet another embodiment, each smaller sphere partially
contacts two adjacent smaller spheres to create a uniquely shaped
continuous band of smaller sphere material that extends
circumferentially within and about the smaller sphere and yet is
disposed within and between the surrounding second core
composition. In this embodiment, the band is comprised of smaller
spheres having at least one different physical property than at
least one physical property of the surrounding second core
composition.
[0045] In one particular embodiment, a golf ball of the invention
comprises a core and a cover, wherein the core has a core center
and comprises between 2 and 20 smaller spheres having diameters of
0.01 to 0.75 inches, the smaller spheres being formed of a first
rubber composition and are surrounded by a second core composition
having at least one different physical property than the first
rubber composition.
[0046] For example, the physical property may be selected from the
group of hardness, compression, coefficient of restitution, and/or
specific gravity.
[0047] In another particular embodiment, a golf ball of the
invention may comprise a core and a cover, wherein the core has a
core center and comprises between 2 and 20 smaller spheres disposed
therein, the plurality of smaller spheres having sphere centers and
being dispersed substantially symmetrically about, but not
concentric with, the core center. In a specific embodiment, all of
the smaller spheres have a diameter and the smaller sphere centers
are spaced from the core center by a distance greater than 1/2 the
diameter.
[0048] In one such embodiment, the smaller spheres are formed of a
first core composition that has a physical property having a first
value and a surrounding portion of the core is comprised of a
second core composition that has the physical property having a
second value that is different than the first value. In a different
such embodiment, at least one smaller sphere is formed of a first
core composition that has a physical property having a first value
and at least one other smaller sphere is formed of a different core
composition that has a physical property having a different value;
and a surrounding portion of the core is comprised of a second core
composition that has a physical property having a second value that
is different than each of the first value and the different
value.
[0049] In one embodiment the inventive core may comprise 2-5
smaller spheres. In another embodiment, the core may comprise 4-8
smaller spheres. In yet another embodiment, the core may comprise
5-10 smaller spheres. In still another embodiment, the core may
comprise 9-12 smaller spheres. In other embodiments, the core may
comprise 11-15 smaller spheres. In alternative embodiments, the
core may comprise 13 to 20 smaller spheres. In some embodiments,
the core may comprise 16-20 smaller spheres.
[0050] Furthermore, there are numerous ways that the smaller
spheres can be equally spaced within the second core composition.
For example, in one non-limiting embodiment, each smaller sphere
can have the same diameter, notwithstanding the preselected number
of spheres.
[0051] In other embodiments, some smaller spheres can have a
different diameter than others. For example, an even number of
smaller spheres such as 6, 8, 10, 12, 14, 16, 18, or 20 can be
preselected wherein a first half of the smaller spheres has a first
diameter, and a second half of the smaller spheres has a second
diameter that is smaller than the first diameter. In these
embodiments, the first half of the smaller spheres are equally
spaced and the second half of the smaller spheres are equally
spaced and the first half of the smaller spheres and the second
half of the smaller spheres can alternate within the surrounding
second core composition.
[0052] In a particular embodiment, 9 smaller spheres can be
preselected, wherein 3 equally spaced smaller spheres have a first
diameter and 6 smaller spheres having a second diameter are equally
spaced in groups of two between the 3 smaller spheres. In this
embodiment, the first diameter is greater than the second
diameter.
[0053] In yet another embodiment, 12 smaller spheres can be
preselected, wherein 4 equally spaced smaller spheres have a first
diameter and 8 smaller spheres having a second diameter are spaced
in equally spaced groups of two between the 4 smaller spheres. In
this embodiment, the first diameter is greater than the second
diameter.
[0054] In still another embodiment, 16 smaller spheres can be
preselected, wherein 4 equally spaced smaller spheres have a first
diameter and 12 smaller spheres having a second diameter are
equally spaced in groups of three between the 4 smaller spheres. In
this embodiment, the first diameter is greater than the second
diameter.
[0055] In an alternative embodiment, 18 smaller spheres can be
preselected, wherein 6 equally spaced smaller spheres have a first
diameter and 12 smaller spheres having a second diameter are
equally spaced in groups of two between the 6 smaller spheres. In
this embodiment, the first diameter is greater than the second
diameter.
[0056] In a different embodiment, 20 smaller spheres can be
preselected, wherein 4 equally spaced smaller spheres have a first
diameter and 16 smaller spheres having a second diameter are
equally spaced in groups of four between the 4 smaller spheres. In
this embodiment, the first diameter is greater than the second
diameter.
[0057] In another embodiment, 15 smaller spheres can be
preselected, wherein 5 equally spaced smaller spheres have a first
diameter and 10 smaller spheres having a second diameter are
equally spaced in groups of two between the 5 smaller spheres. In
this embodiment, the first diameter is greater than the second
diameter.
[0058] In a particular embodiment, 16 smaller spheres can be
preselected, wherein a first group of 4 equally spaced smaller
spheres have a first diameter, and a second group of 4 equally
spaced smaller spheres having a second diameter are spaced between
each of the 4 equally spaced smaller spheres of the first group,
and 8 equally smaller spheres having a third diameter are each
spaced between a smaller sphere of the first group and a smaller
sphere of the second group. In this embodiment, the first diameter
is greater than the second diameter which in turn is greater than
the third diameter.
[0059] In specific embodiments, the total volume of the smaller
spheres may comprise up to one quarter of the total volume of the
core, or up to one third of the total volume of the core, or up to
one half of the total volume of the core, or at least one quarter
of the total volume of the core, or at least one third of the total
volume of the core, or at least one half of the total volume of the
core, or greater than one quarter of the total volume of the core,
or greater than one third of the total volume of the core, or
greater than one half of the total volume of the core.
[0060] Advantageously, each of the first rubber
composition(s)/first core composition(s) and the second core
composition can be formed as known in the golf ball art to target a
predetermined first value, second value, and third value.
Non-limiting examples of physical property differences that can be
created within and between each smaller sphere and the surrounding
second core composition are as follows.
[0061] A hardness gradient of the resulting core is defined by
hardness measurements made at the surface of the core and at points
radially inward towards the geometric center of the core, typically
at 2-mm increments. Given that in some embodiments the smaller
spheres are spaced rather than abutting, the hardness measurement
profile will be different when taking measurements radially inward
from some points on the outer surface of the core than when taking
measurements radially inward from other points on the outer surface
of the core.
[0062] As used herein, the terms "negative" and "positive" hardness
gradients refer to the result of subtracting the hardness value at
the innermost portion of the component being measured from the
hardness value at the outer surface of the component being
measured. Accordingly, in cores of the invention, if the outer
surface of the core has a lower hardness value than does the
geometric center (i.e., the surface is softer than the geometric
center), the hardness gradient will be deemed a "negative" gradient
(a smaller number-a larger number=a negative number).
[0063] And with respect to outer layers, if the outer surface of
the outer layer has a has a greater hardness value than the inner
surface of the outer core layer, this is a "hard-to-soft" or
"positive" hardness gradient as measured radially inward from the
outer layer outer surface. It is also possible to create a "zero"
hardness gradient, which is generally defined as no gradient as
well as a gradient of less than 1 Shore C hardness point in either
the negative or positive hardness gradient direction. Methods for
measuring the hardness of the inner core and surrounding layers and
determining the hardness gradients are well known.
[0064] A positive hardness gradient having a magnitude of from
about 1 to about 7 Shore C hardness points generally defines a
shallow positive hardness gradient. A positive hardness gradient
having a magnitude of greater than about 7 to about 22 Shore C
hardness points generally defines a "medium" positive hardness
gradient. In turn, positive hardness gradient having a magnitude of
more than about 22 Shore C hardness points generally defines a
"steep" positive hardness gradient.
[0065] A hardness gradient having a magnitude within +1 or -1 Shore
C hardness point is generally considered to define a "zero"
hardness gradient.
[0066] And an outer surface hardness that is less than the
respective geometric center hardness/inner surface hardness by more
than about 1 Shore C hardness point is generally considered to
define a negative hardness gradient.
[0067] Thus, the core of a golf ball of the invention may have
various hardnesses and hardness gradients between the smaller
spheres themselves as well as between each smaller sphere and the
surrounding second core composition depending on the particular
golf ball playing characteristics being targeted. Each smaller
sphere is disposed within the surrounding second core composition
such that the smaller sphere is suspended within the second core
composition rather than being anchored to or interconnected with
the center of the core. These novel core constructions permit
manufacture of unique resulting golf ball playing characteristics
and performance properties.
[0068] Core hardness can range, for example, from 35 Shore C to
about 98 Shore C, or 50 Shore C to about 90 Shore C, or 60 Shore C
to about 85 Shore C, or 45 Shore C to about 75 Shore C, or 40 Shore
C to about 85 Shore C. In other embodiments, core hardness can
range, for example, from about 20 Shore D to about 78 Shore D, or
from about 30 Shore D to about 60 Shore D, or from about 40 Shore D
to about 50 Shore D, or 50 Shore D or less, or greater than 50
Shore D.
[0069] In one specific non-limiting example, a resulting golf ball
of the invention includes a core comprised of smaller spheres with
a Shore C hardness of from about 70 Shore C to about 75 Shore C and
the surrounding second core composition having a Shore C hardness
of from about 85 Shore C to about 90 Shore C; and wherein the Shore
C hardness of the surrounding second core composition is greater
than the Shore C hardness of at least some of the smaller spheres
by at least 15 Shore C hardness points to create a positive Shore C
hardness gradient.
[0070] In a different example, the hardness of each sphere may be
less than a hardness of the surrounding second core composition to
define a first positive hardness gradient of about 1 to 12 Shore C
hardness points. At least one cover layer is formed over/about this
core.
[0071] Alternatively, the hardness of each sphere may be less than
a hardness of the surrounding second core composition to define a
first positive hardness gradient of about 12 to 22 Shore C hardness
points. At least one cover layer is formed over/about this
core.
[0072] In yet other examples, the surrounding second core
composition may have hardness that is greater than a hardness of
each sphere of the resulting core to define a positive hardness
gradient of at least 15 Shore C hardness points.
[0073] For example, in one non-limiting example, the smaller
spheres may have a hardness of from about 70 Shore C to about 73
Shore C, the hardness of the surrounding second core composition
may be from about 86 Shore C to about 89 Shore C; wherein the
hardness of the surrounding second core composition is greater than
the hardness of each sphere by at least 16 Shore C hardness
points.
[0074] Embodiments are also envisioned wherein the resulting core
has a surrounding second core composition hardness that is greater
than the hardness of each smaller sphere to define a positive
hardness gradient of at least 20 Shore C hardness points, or at
least 25 Shore C hardness points, or at least 30 Shore C hardness
points, or at least 35 Shore C hardness points, etc.
[0075] In any of these embodiments, at least one cover layer may be
formed over/about the core; and optionally, at least one
intermediate layer may be disposed between the core and the
cover.
[0076] Of course, advantageously, a resulting golf ball of the
invention comprised of a core created using within a plurality of
smaller spheres disposed within surrounding second core composition
may have any known hardness gradient and in any known hardness
scale in the golf ball art such as Shore C, Shore D, Shore M,
etc.
[0077] Likewise, a core of a golf ball of the invention may have
various compressions and compression differences between the
smaller spheres themselves as well as between each smaller sphere
and the surrounding second core composition depending on the
particular golf ball playing characteristics being targeted.
[0078] For example, in one embodiment, all spheres may have the
same compression which is lower than a compression of the
surrounding second core composition. In another embodiment, all
spheres may have the same compression which is greater than a
compression of the surrounding second core composition.
[0079] In some embodiments, at least one smaller sphere may have a
different compression than at least one other smaller sphere. In
one such embodiment, alternating smaller spheres have the same
compression and all spheres have a compression that is lower than a
compression of the surrounding second core composition. In another
such embodiment, alternating smaller spheres have the same
compression and some smaller spheres have a compression that is
lower than a compression of the surrounding second core composition
while other smaller spheres have a compression that is greater than
a compression of the surrounding second core composition.
[0080] In turn, a core of a golf ball of the invention may have
various coefficient of restitutions and coefficient of restitution
differences between the smaller spheres themselves as well as
between each smaller sphere and the surrounding second core
composition depending on the particular golf ball playing
characteristics being targeted.
[0081] For example, in one embodiment, all spheres may have the
same coefficient of restitution which is lower than a coefficient
of restitution of the surrounding second core composition. In
another embodiment, all spheres may have the same coefficient of
restitution which is greater than a coefficient of restitution of
the surrounding second core composition.
[0082] In some embodiments, at least one smaller sphere may have a
different coefficient of restitution than at least one other
smaller sphere. In one such embodiment, alternating smaller spheres
have the same coefficient of restitution and all spheres have a
coefficient of restitution that is lower than a coefficient of
restitution of the surrounding second core composition. In another
such embodiment, alternating smaller spheres have the same
coefficient of restitution and some smaller spheres have a
coefficient of restitution that is lower than a coefficient of
restitution of the surrounding second core composition while other
smaller spheres have a coefficient of restitution that is greater
than a coefficient of restitution of the surrounding second core
composition.
[0083] Meanwhile, a core of a golf ball of the invention may have
various specific gravities and specific gravity differences between
the smaller spheres themselves as well as between each smaller
sphere and the surrounding second core composition depending on the
particular golf ball playing characteristics being targeted.
[0084] For example, in one embodiment, all spheres may have the
same specific gravity which is lower than a specific gravity of the
surrounding second core composition. In another embodiment, all
spheres may have the same specific gravity which is greater than a
specific gravity of the surrounding second core composition.
[0085] In some embodiments, at least one smaller sphere may have a
different specific gravity than at least one other smaller sphere.
In one such embodiment, alternating smaller spheres have the same
specific gravity and all spheres have a specific gravity that is
lower than a specific gravity of the surrounding second core
composition. In another such embodiment, alternating smaller
spheres have the same specific gravity and some smaller spheres
have a specific gravity that is lower than a specific gravity of
the surrounding second core composition while other smaller spheres
have a specific gravity that is greater than a specific gravity of
the surrounding second composition.
[0086] It is therefore contemplated that physical property
differences can be created between smaller spheres, between each
smaller sphere and the surrounding second core composition, and
within the surrounding second core composition itself. And it is to
be further understood that hardness, compression, coefficient of
restitution and/or specific gravity are specific examples of the
numerous other physical property differences that can be created
within a novel core of the invention and between the novel core of
the invention and outer golf ball layers of a resulting golf ball
of the invention.
[0087] In some embodiments, none of the 2 and 20 smaller spheres
contact each other, that is, each smaller sphere is entirely
surrounded by the second core composition within the core.
[0088] In other embodiments, a portion of an outer surface of at
least one smaller sphere may abut/contact a portion of an outer
surface of at least one other smaller sphere; but the smaller
spheres are not otherwise connected/interconnected.
[0089] Advantageously, in a golf ball of the invention, the smaller
spheres may be spaced within the second core composition without
the need for any central hub and/or without otherwise being
interconnected by rods or other interconnecting means or
elements/structure.
[0090] In one embodiment, a plurality of the smaller spheres have
sphere centers that are equally spaced from the core center.
[0091] In another embodiment, the smaller spheres have sphere
centers that are equally spaced from the core center.
[0092] In specific embodiments, smaller spheres may have diameters
of 0.01 to 0.75 inches, or between 0.2 inches and 0.75 inches, or
between 0.3 inches and 0.75 inches, or between 0.4 inches and 0.75
inches, or between 0.5 inches and 0.75 inches, or between 0.2
inches and 0.5 inches, or between 0.3 inches and 0.5 inches.
[0093] In a particular embodiment, the smaller spheres abut at
least one adjacent smaller sphere.
[0094] In one embodiment, the second core composition is selected
from the group of thermoset rubber compositions and/or
thermoplastic compositions.
[0095] In a specific embodiment, the smaller spheres have a
diameter that is equal to each other and have a mass that is equal
to each other.
[0096] In a different embodiment, a first portion of the smaller
spheres have a first diameter and a second portion of the smaller
spheres have a second diameter that is less than the first
diameter.
[0097] For example, the physical property may be selected from the
group of hardness, compression, coefficient of restitution, and/or
specific gravity.
[0098] In a specific embodiment, all of the smaller spheres have a
diameter and the sphere centers are spaced from the core center by
a distance greater than 1/2 the diameter.
[0099] In a particular embodiment, the first core composition is
selected from the group of thermoset compositions, thermoplastic
compositions, metal-based compositions, and/or blends thereof. In
another specific embodiment, the second core composition is
selected from the group of thermoset compositions, thermoplastic
compositions, metal-based compositions, and/or blends thereof.
[0100] For example, the first core composition and/or second core
composition may comprise rubber compositions such as polybutadiene,
ethylene-propylene rubber, ethylene-propylene-diene rubber,
polyisoprene, styrene-butadiene rubber, polyalkenamers, butyl
rubber, halobutyl rubber, polystyrene elastomers, and/or castable
liquid rubber compositions.
[0101] Additionally, the first core composition and/or second core
composition may be comprised for example of partially-neutralized
ionomers and highly-neutralized ionomers (HNPs), including ionomers
formed from blends of two or more partially-neutralized ionomers,
blends of two or more highly-neutralized ionomers, and blends of
one or more partially-neutralized ionomers with one or more
highly-neutralized ionomers.
[0102] Ionomers, typically are ethylene/acrylic acid copolymers or
ethylene/acrylic acid/acrylate terpolymers in which some or all of
the acid groups are neutralized with metal cations. Commercially
available ionomers suitable for use with the present invention
include for example SURLYNs.RTM. from DuPont and Ioteks.RTM. from
Exxon. SURLYN.RTM. 8940 (Na), SURLYN.RTM. 9650 (Zn), and
SURLYN.RTM. 9910 (Zn) are examples of low acid ionomer resins with
the acid groups that have been neutralized to a certain degree with
a cation. More examples of suitable low acid ionomers, e.g.,
Escor.RTM. 4000/7030 and Escor.RTM. 900/8000, are disclosed in U.S.
Pat. Nos. 4,911,451 and 4,884,814, the disclosures of which are
incorporated by reference herein. High acid ionomer resins include
SURLYN(.RTM. 8140 (Na) and SURLYN.RTM. 8546 (Li), which have an
methacrylic acid content of about 19 percent. The acid groups of
these high acid ionomer resins that have been neutralized to a
certain degree with the designated cation.
[0103] Ionomers may encompass those polymers obtained by
copolymerization of an acidic or basic monomer, such as alkyl
(meth)acrylate, with at least one other comonomer, such as an
olefin, styrene or vinyl acetate, followed by at least partial
neutralization. Alternatively, acidic or basic groups may be
incorporated into a polymer to form an ionomer by reacting the
polymer, such as polystyrene or a polystyrene copolymer including a
block copolymer of polystyrene, with a functionality reagent, such
as a carboxylic acid or sulfonic acid, followed by at least partial
neutralization. Suitable neutralizing sources include cations for
negatively charged acidic groups and anions for positively charged
basic groups.
[0104] The first core composition and/or second core composition
may comprise ionomers obtained by providing a cross metallic bond
to polymers of monoolefin with at least one member selected from
the group consisting of unsaturated mono- or di-carboxylic acids
having 3 to 12 carbon atoms and esters thereof (the polymer
contains about 1 percent to about 50 percent by weight of the
unsaturated mono- or di-carboxylic acid and/or ester thereof). In
one embodiment, the ionomer is an E/X/Y copolymers where E is
ethylene, X is a softening comonomer, such as acrylate or
methacrylate, present in 0 percent to about 50 percent by weight of
the polymer (preferably 0 weight percent to about 25 weight
percent, most preferably 0 weight percent to about 20 weight
percent), and Y is acrylic or methacrylic acid present in about 5
to about 35 weight percent of the polymer, wherein the acid moiety
is neutralized about 1 percent to about 100 percent (preferably at
least about 40 percent, most preferably at least about 60 percent)
to form an ionomer by a cation such as lithium, sodium, potassium,
magnesium, calcium, barium, lead, tin, zinc, or aluminum, or a
combination of such cations.
[0105] The first core composition and/or second core composition
may comprise thermosetting polyurethanes which may be formed as
known in the golf ball art.
[0106] The first core composition and/or second core composition
may comprise thermoplastic polyurethanes such as but not limited to
those sold under the tradenames of Texin.RTM. 250. Texin.RTM. 255.
Texin.RTM. 260, Texin.RTM. 270, Texin.RTM.950U, Texin.RTM. 970U,
Texin.RTM.1049, Texin.RTM.990DP7-1191, Texin.RTM. DP7-1202,
Texin.RTM.990R, Texin.RTM.993, Texin.RTM.DP7-1049. Texin.RTM. 3203,
Texin.RTM. 4203, Texin.RTM. 4206, Texin.RTM. 4210, Texin.RTM. 4215,
and Texin.RTM. 3215, each commercially available from Covestro LLC.
Pittsburgh Pa.; Estane.RTM. 50 DT3, Estane.RTM.58212,
Estane.RTM.55DT3, Estane.RTM.58887, Estane.RTM.EZ14-23A,
Estane.RTM.ETE 50DT3, each commercially available from Lubrizol
Company of Cleveland, Ohio; and Elastollan.RTM.WY1149,
Elastollan.RTM. 1154D53, Elastollan.RTM. 1180A, Elastollan.RTM.
1190A, Elastollan.RTM.1195A, Elastollan.RTM.1185AW, Elastollan.RTM.
1175AW, each commercially available from BASF; Desmopan.RTM. 453,
commercially available from Bayer of Pittsburgh, Pa. and the
E-Series TPUs, such as D 60 E 4024 commercially available from
Huntsman Polyurethanes of Germany.
[0107] Other suitable thermoplastic polymers include, but are not
limited to, the following polymers (including homopolymers,
copolymers, and derivatives thereof: (a) polyester, particularly
those modified with a compatibilizing group such as sulfonate or
phosphonate, including modified poly(ethylene terephthalate),
modified poly(butylene terephthalate), modified poly(propylene
terephthalate), modified poly(trimethylene terephthalate), modified
poly(ethylene naphthenate), and those disclosed in U.S. Pat. Nos.
6,353,050, 6,274,298, and 6,001,930, the entire disclosures of
which are hereby incorporated herein by reference, and blends of
two or more thereof; (b) polyamides, polyamide-ethers, and
polyamide-esters, and those disclosed in U.S. Pat. Nos. 6,187,864,
6,001,930, and 5,981,654, the entire disclosures of which are
hereby incorporated herein by reference, and blends of two or more
thereof; (c) polyurethane-polyurea hybrids, and blends of two or
more thereof; (d) fluoropolymers, such as those disclosed in U.S.
Pat. Nos. 5,691,066, 6,747,110 and 7,009,002, the entire
disclosures of which are hereby incorporated herein by reference,
and blends of two or more thereof; (e) polystyrenes, such as
poly(styrene-co-maleic anhydride), acrylonitrile-butadiene-styrene,
poly(styrene sulfonate), polyethylene styrene, and blends of two or
more thereof; (f) polyvinyl chlorides and grafted polyvinyl
chlorides, and blends of two or more thereof; (g) polycarbonates,
blends of polycarbonate/acrylonitrile-butadiene-styrene, blends of
polycarbonate/polyurethane, blends of polycarbonate/polyester, and
blends of two or more thereof; (h) polyethers, such as polyarylene
ethers, polyphenylene oxides, block copolymers of alkenyl aromatics
with vinyl aromatics and polyamicesters, and blends of two or more
thereof; (i) polyimides, polyetherketones, polyamideimides, and
blends of two or more thereof; and (j) polycarbonate/polyester
copolymers and blends.
[0108] It also is recognized that thermoplastic materials can be
"converted" into thermoset materials by cross-linking the polymer
chains so they form a network structure, and such cross-linked
thermoplastic materials may be used to form the core and
intermediate layers in accordance with this invention. For example,
thermoplastic polyolefins such as linear low density polyethylene
(LLDPE), low density polyethylene (LDPE), and high density
polyethylene (HDPE) may be cross-linked to form bonds between the
polymer chains. The cross-linked thermoplastic material typically
has improved physical properties and strength over non-cross-linked
thermoplastics, particularly at temperatures above the crystalline
melting point. Preferably a partially or fully-neutralized ionomer,
as described above, is covalently cross-linked to render it into a
thermoset composition (that is, it contains at least some level of
covalent, irreversible cross-links). Thermoplastic polyurethanes
and polyureas also may be converted into thermoset materials in
accordance with the present invention.
[0109] The cross-linked thermoplastic material may be created by
exposing the thermoplastic to: 1) a high-energy radiation
treatment, such as electron beam or gamma radiation, such as
disclosed in U.S. Pat. No. 5,891,973, which is incorporated by
reference herein, 2) lower energy radiation, such as ultra-violet
(UV) or infra-red (IR) radiation; 3) a solution treatment, such as
an isocyanate or a silane; 4) incorporation of additional free
radical initiator groups in the thermoplastic prior to molding;
and/or 5) chemical modification, such as esterification or
saponification, to name a few.
[0110] Modifications in thermoplastic polymeric structure can be
induced by a number of methods, including exposing the
thermoplastic material to high-energy radiation or through a
chemical process using peroxide. Radiation sources include, but are
not limited to, gamma-rays, electrons, neutrons, protons, x-rays,
helium nuclei, or the like. Gamma radiation, typically using
radioactive cobalt atoms and allows for considerable depth of
treatment, if necessary. For core layers requiring lower depth of
penetration, electron-beam accelerators or UV and IR light sources
can be used. Useful UV and IR irradiation methods are disclosed in
U.S. Pat. Nos. 6,855,070 and 7,198,576, which are incorporated
herein by reference. The thermoplastic layers may be irradiated at
dosages greater than 0.05 Mrd, or ranging from 1 Mrd to 20 Mrd, or
ranging from 2 Mrd to 15 Mrd, or ranging from 4 Mrd to 10 Mrd. In
one embodiment, the layer may be irradiated at a dosage from 5 Mrd
to 8 Mrd and in another embodiment, the layer may be irradiated
with a dosage from 0.05 Mrd to 3 Mrd, or from 0.05 Mrd to 1.5
Mrd.
[0111] A plurality of the smaller spheres are preferably solid or
foamed.
[0112] Each of a plurality of the smaller spheres may have a hollow
portion that is encased with the first composition.
[0113] The invention also relates to a method of making a golf ball
comprising the steps of: i) forming a spherical core by: a)
providing between 2 and 20 smaller spheres; each having a diameter
of from 0.01 inches to 0.75 inches and being formed by injection
molding, compression molding or casting a first rubber composition
into the smaller sphere; and b) spacing each smaller sphere within
a second core composition that has at least one different physical
property than the first rubber composition before the second core
composition is fully cured; and ii) forming at least a cover about
the spherical core.
[0114] In another embodiment, the method of making a golf ball
comprises the steps of: providing a spherical core having a core
center and between 2 and 20 smaller spheres spaced within the core
substantially symmetrically about, but not concentric with, the
core center, and forming at least a cover about the core; wherein
each smaller sphere comprises a composition that is injection
molded, compression molded or cast into the smaller sphere before
the smaller sphere is spaced within the core; and wherein each
smaller sphere is surrounded in the core by a second core
composition having at least one different physical property than
the composition of each smaller sphere. Embodiments are envisioned
wherein all smaller spheres are formed of the same composition.
Alternatively, at least one smaller sphere is formed of a different
composition than at least one other smaller sphere. And
advantageously, once again, the smaller spheres may be spaced
within the surrounding second core composition without the need for
any central hub and without otherwise being interconnected by rods
or other interconnecting means or element.
[0115] It is envisioned that the smaller spheres can be comprised
of any material including thermoset materials, thermoplastic
materials, foamed materials and/or or metals. In a particular
embodiment, the smaller spheres are comprised of polybutadiene
rubber.
[0116] In some embodiments, the smaller spheres can also vary in
size and weight--that is, each sphere may or may not be equal in
size and weight to each of the other spheres.
[0117] Each smaller sphere can be pre-formed using any known method
such as injection molding, compression molding or casting.
[0118] Subsequently, each smaller sphere may be formed within the
second core composition using methods such as the following. In one
embodiment, the surrounding second core composition may be
injection molded about each smaller sphere which is secured in
place in a predetermined pattern. In another embodiment, casting
may be used wherein each smaller sphere is deposited in a
predetermined pattern within in a casting mold containing the
second core composition before final cure of the second core
composition.
[0119] In yet another embodiment, each smaller sphere can be
deposited within the inner surface a first half-shell comprised of
second core composition followed by mating an identical second half
shell comprised of second core composition with the first
half-shell and thereby also about the smaller spheres followed by
compression molding assembly of the first and second half shells
and smaller spheres disposed therein.
[0120] In some embodiments, every smaller sphere is entirely
surrounded by the surrounding second core composition. In other
embodiments, some of the smaller spheres are entirely surrounded by
the surrounding second core composition while other smaller spheres
have an outer surface portion that is in contact with/abutting an
outer surface portion of an adjacent smaller sphere. In yet other
embodiments, every smaller sphere has an outer surface portion that
is in contact with/abuts an outer surface portion of an adjacent
smaller sphere.
[0121] Thermoset and thermoplastic layers herein may be treated in
such a manner as to create a positive or negative hardness gradient
within and between golf ball layers. In golf ball layers of the
present invention wherein a thermosetting rubber is used,
gradient-producing processes and/or gradient-producing rubber
formulation may be employed. Gradient-producing processes and
formulations are disclosed more fully, for example, in U.S. patent
application Ser. No. 12/048,665, filed on Mar. 14, 2008; Ser. No.
11/829,461, filed on Jul. 27, 2007; Ser. No. 11/772,903, filed Jul.
3, 2007; Ser. No. 11/832,163, filed Aug. 1, 2007; Ser. No.
11/832,197, filed on Aug. 1, 2007; the entire disclosure of each of
these references is hereby incorporated herein by reference.
[0122] After the golf balls have been removed from the mold, they
may be subjected to finishing steps such as flash-trimming,
surface-treatment, marking, and one or more coating layer may be
applied as desired via methods such as spraying, dipping, brushing,
or rolling. Then the golf ball can go through a series of finishing
steps.
[0123] For example, in traditional white-colored golf balls, the
white-pigmented outer cover layer may be surface-treated using a
suitable method such as, for example, corona, plasma, or
ultraviolet (UV) light-treatment. In another finishing process, the
golf balls are painted with one or more paint coatings. For
example, white or clear primer paint may be applied first to the
surface of the ball and then indicia may be applied over the primer
followed by application of a clear polyurethane top-coat. Indicia
such as trademarks, symbols, logos, letters, and the like may be
printed on the outer cover or prime-coated layer, or top-coated
layer using pad-printing, ink-jet printing, dye-sublimation, or
other suitable printing methods. Any of the surface coatings may
contain a fluorescent optical brightener.
[0124] The core in a golf ball of this invention provides the ball
with a variety of advantageous mechanical and playing performance
properties as discussed further below. In general, the hardness,
diameter, and thickness of the different ball layers may vary
depending upon the desired ball construction. Thus, golf balls of
the invention may have any known overall diameter and any known
number of different layers and layer thicknesses, wherein the
inventive core is incorporated within those layers in order to
target desired playing characteristics without sacrificing flight
symmetry and putting trajectory.
[0125] Herein, a golf ball is considered to achieve flight symmetry
when it is found, under calibrated testing conditions, to fly at
substantially the same height and distance, and remain in flight
for substantially the same period of time, regardless of how it is
placed on the tee. The testing conditions for assessing flight
symmetry of a golf ball are provided in USGA-TPX3006, Revision 3.0,
"Actual Launch Conditions Overall Distance and Symmetry Test
Procedure".
[0126] Unless otherwise defined, all terms (including technical and
scientific terms) used herein have the same meaning as commonly
understood by one of ordinary skill in the art of this disclosure.
It will be further understood that terms, such as those defined in
commonly used dictionaries, should be interpreted as having a
meaning that is consistent with their meaning in the context of the
specification and should not be interpreted in an idealized or
overly formal sense unless expressly so defined herein. Well known
functions or constructions may not be described in detail for
brevity or clarity.
[0127] The terms "about" and "approximately" shall generally mean
an acceptable degree of error or variation for the quantity
measured given the nature or precision of the measurements.
Typical, exemplary degrees of error or variation are within 20
percent (%), preferably within 10%, and more preferably within 5%
of a given value or range of values. Numerical quantities given in
this description are approximate unless stated otherwise, meaning
that the term "about" or "approximately" can be inferred when not
expressly stated.
[0128] Notwithstanding that the numerical ranges and parameters
setting forth the broad scope of the invention are approximations,
the numerical values set forth in the specific examples are
reported as precisely as possible. Any numerical value, however,
inherently contains certain errors necessarily resulting from the
standard deviation found in their respective testing measurements.
Furthermore, when numerical ranges of varying scope are set forth
herein, it is contemplated that any combination of these values
inclusive of the recited values may be used.
[0129] The terminology used herein is for the purpose of describing
particular embodiments only and is not intended to be limiting. As
used herein, the singular forms "a", "an" and "the" are intended to
include the plural forms as well (i.e., at least one of whatever
the article modifies), unless the context clearly indicates
otherwise.
[0130] The inventive cores according to the present disclosure may
be used with practically any type of ball construction. For
instance, the golf ball may have a two-piece design, a double
cover, or veneer cover construction depending on the type of
performance desired of the ball. Other suitable golf ball
constructions include dual cores, and multiple intermediate
layers.
[0131] Different materials may be used in the construction of golf
balls according to the present disclosure. For example, the cover
of the ball may be made of a thermoset or thermoplastic, a castable
or non-castable polyurethane and polyurea, an ionomer resin,
balata, or any other suitable cover material known to those skilled
in the art. Conventional and non-conventional materials may be used
for forming core and intermediate layers of the ball including
polybutadiene and other rubber-based core formulations, ionomer
resins, highly neutralized polymers, and the like. And it is
contemplated that each and all of the smaller spheres and/or the
surrounding second core composition of golf balls of the invention
may comprise any known golf ball material.
[0132] The golf balls of the present disclosure may be formed using
a variety of application techniques. For example, the golf ball
layers may be formed using compression molding, flip molding,
injection molding, retractable pin injection molding, reaction
injection molding (RIM), liquid injection molding (LIM), casting,
vacuum forming, powder coating, flow coating, spin coating,
dipping, spraying, and the like. Conventionally, compression
molding and injection molding are applied to thermoplastic
materials, whereas RIM, liquid injection molding, and casting are
employed on thermoset materials.
[0133] The dimple count on the golf balls contemplated by the
present disclosure may be varied. As used herein, the "dimple
count" of a golf ball refers to how many dimples are present on the
golf ball. The total number of dimples may be based on, for
instance, the number of differently sized dimples, the maximum and
minimum diameters of the dimples, the dimple arrangement, and the
desired surface coverage.
[0134] In one embodiment, the total number of dimples may be less
than about 350 dimples. For example, the total number of dimples on
the golf ball may be about 328. In another embodiment, the total
number of dimples on the golf ball may be about 344. In still
another embodiment, the total number of dimples on the golf ball
may be about 348.
[0135] In another embodiment, the total number of dimples on the
golf ball may range from about 350 dimples to about 500 dimples.
For instance, the total number of dimples may be about 352 dimples.
In another embodiment, the total number of dimples may be about 388
dimples.
[0136] The golf balls described and claimed herein are not to be
limited in scope by the specific embodiments herein disclosed,
since these embodiments are intended as illustrations of several
aspects of the disclosure. Any equivalent embodiments are intended
to be within the scope of this disclosure. Indeed, various
modifications of the device in addition to those shown and
described herein will become apparent to those skilled in the art
from the foregoing description. Such modifications are also
intended to fall within the scope of the appended claims. All
patents and patent applications cited in the foregoing text are
expressly incorporated herein by reference in their entirety. Any
section headings herein are provided only for consistency with the
suggestions of 37 C.F.R. .sctn. 1.77 or otherwise to provide
organizational queues. These headings shall not limit or
characterize the invention(s) set forth herein.
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