U.S. patent application number 12/878510 was filed with the patent office on 2012-03-15 for formulating technique for casting aliphatic golf ball covers.
Invention is credited to Brian Comeau, Randy Petrichko, Shawn Ricci.
Application Number | 20120064999 12/878510 |
Document ID | / |
Family ID | 45807257 |
Filed Date | 2012-03-15 |
United States Patent
Application |
20120064999 |
Kind Code |
A1 |
Ricci; Shawn ; et
al. |
March 15, 2012 |
FORMULATING TECHNIQUE FOR CASTING ALIPHATIC GOLF BALL COVERS
Abstract
A golf ball having a cover is cast from a castable reactive
aliphatic functional composition consisting essentially of: a
methylene dicyclohexyl diisocyanate based prepolymer; at least one
polyamine/polyamide functional component used as a backbone of the
prepolymer; a free isocyanate group; and a curative. The
polyamine/polyamide is formed from the condensation reaction of a
polyamine and a polyacid, with the equivalent ratio of polyamine to
polyacid ranges from 2:1 to 10:1, preferably the ratio is 3:1, and
more preferably 2:1. It is preferable that the polyamine be a
Jeffamine series D-2000. The polyacid can be chosen from acids such
as maleic, adipic, azelaic or sebacic. It is preferable that the
prepolymer be a polyurethane or urea. The formulating techniques
eliminate the need for post curing when using aliphatic chemistries
in golf ball covers.
Inventors: |
Ricci; Shawn; (New Bedford,
MA) ; Petrichko; Randy; (Richmond, RI) ;
Comeau; Brian; (Berkley, MA) |
Family ID: |
45807257 |
Appl. No.: |
12/878510 |
Filed: |
September 9, 2010 |
Current U.S.
Class: |
473/378 |
Current CPC
Class: |
A63B 37/0024 20130101;
C08G 18/10 20130101; C08G 18/758 20130101; C08G 18/5039
20130101 |
Class at
Publication: |
473/378 |
International
Class: |
A63B 37/12 20060101
A63B037/12 |
Claims
1. A golf ball comprising: a core; and a cover, wherein the cover
is cast from a castable reactive aliphatic functional composition
consisting essentially of: a methylene dicyclohexyl diisocyanate
based prepolymer; at least one polyamine/polyamide functional
component used as a backbone of the prepolymer; a free isocyanate
group; and a curative.
2. The golf ball of claim 1, wherein the polyamine/polyamide is
formed from the condensation reaction of a polyamine and a
polyacid, with the equivalent ratio of polyamine to polyacid ranges
from 2:1 to 10:1.
3. The golf ball of claim 2, wherein the equivalent ration is
3:1.
4. The golf ball of claim 2, wherein the equivalent ration is
2:1.
5. The golf ball of claim 1, wherein the polyamine is a Jeffamine
series D-2000.
6. The golf ball of claim 1, wherein the polyacid may be is
selected from the group consisting of maleic acid, adipic acid,
azelaic acid and sebacic acid.
7. The golf ball of claim 1, wherein the prepolymer is a
polyurethane.
8. The golf ball of claim 1, wherein the prepolymer is urea.
9. The golf ball of claim 1 wherein the free isocyanate group is
6.4% of the cover composition.
10. A golf ball comprising: a core; and a cover, wherein the cover
is cast from a castable reactive aliphatic functional composition
consisting essentially of: a methylene dicyclohexyl diisocyanate
based prepolymer; a free isocyanate group; and a curative including
at least one polyamine/polyamide functional component
11. The golf ball of claim 1, wherein the polyamine/polyamide
functional component is formed from the condensation reaction of a
polyamine and a polyacid, with the equivalent ratio of polyamine to
polyacid ranges from 2:1 to 10:1.
12. The golf ball of claim 2, wherein the equivalent ration is
3:1.
13. The golf ball of claim 2, wherein the equivalent ration is
2:1.
14. The golf ball of claim 1, wherein the polyamine is a Jeffamine
series D-2000.
15. The golf ball of claim 1, wherein the polyacid may be is
selected from the group consisting of maleic acid, adipic acid,
azelaic acid and sebacic acid.
16. The golf ball of claim 1, wherein the prepolymer is a
polyurethane.
17. The golf ball of claim 1, wherein the prepolymer is urea.
18. The golf ball of claim 1 wherein the free isocyanate group is
6.4% of the cover composition.
Description
FIELD OF THE INVENTION
[0001] The present invention is directed to novel formulating
techniques that eliminate the need for post curing or delay times
when utilizing aliphatic chemistries in golf ball covers. More
specifically, it achieves this by incorporating amide linkages into
either the pre-polymer backbone or the curing agent.
BACKGROUND OF THE INVENTION
[0002] Golf ball components are formed from a variety of
compositions. For example, golf ball cores, intermediate layers,
and covers may be formed from materials ranging from balata to
ionomer resin to polyurethane or polyurea. Manufacturers constantly
is experiment with the different materials for use in the various
golf ball layers in order to provide a golf ball that has desirable
aerodynamic properties, "soft" feel, and increased durability.
[0003] For example, balata covered balls are favored by more highly
skilled golfers because the softness of the cover allows the player
to achieve spin rates sufficient to more precisely control ball
direction and distance, particularly on shorter shots. However,
balata covered balls lack durability and are therefore easily
damaged, thus balata is almost never used today.
[0004] Alternative cover compositions have been developed in an
attempt to provide balls with spin rates and a feel approaching
those of balata covered balls, while also providing a golf ball
with a higher durability and overall distance. For instance,
ionomer resins have, to a large extent, replaced balata as a cover
material. Chemically, ionomer resins are a copolymer of an olefin
and an .alpha.,.beta.-ethylenically-unsaturated carboxylic acid
having 10 to 90 percent of the carboxylic acid groups neutralized
by a metal ion, as disclosed in U.S. Pat. No. 3,264,272.
Commercially available ionomer resins include, for example,
copolymers of ethylene and methacrylic or acrylic acid, neutralized
with metal salts. Examples of commercially available ionomer resins
include, but are not limited to, SURLYN.RTM. from DuPont de Nemours
and Company, and ESCOR.RTM. and IOTEK.RTM. from Exxon Corporation.
These ionomer resins are distinguished by the type of metal ion,
the amount of acid, and the degree of neutralization.
[0005] U.S. Pat. Nos. 3,454,280, 3,819,768, 4,323,247, 4,526,375,
4,884,814, and 4,911,451 all relate to the use of SURLYN.RTM.-type
compositions in golf ball covers. However, while SURLYN.RTM.
covered golf balls, as described in the preceding patents, possess
virtually cut-proof covers, the spin and feel are inferior compared
to balata covered balls.
[0006] Polyurethanes have also been recognized as useful materials
for golf ball covers since about 1960. For example, U.S. Pat. No.
4,123,061 teaches a golf ball made from a polyurethane prepolymer
formed of polyether with diisocyanate that is cured with either a
polyol or an amine-type curing agent. U.S. Pat. No. 5,334,673
discloses the use of two categories of polyurethane available on
the market, i.e., thermoset and thermoplastic polyurethanes, for
forming golf ball covers and, in particular, thermoset is
polyurethane covered golf balls made from a composition of
polyurethane prepolymer and a slow-reacting amine curing agent,
and/or a glycol.
[0007] Unlike ionomer resin covered golf balls, polyurethane golf
ball covers can be formulated to possess the soft "feel" of balata
covered golf balls. However, golf ball covers made from
polyurethane have not, to date, fully matched ionomer resin golf
balls with respect to resilience or the rebound of the golf ball
cover, which is a function of the initial velocity of a golf ball
after impact with a golf club.
[0008] Polyureas have also been proposed as cover materials for
golf balls. For instance, U.S. Pat. No. 5,484,870 discloses a
polyurea composition comprising the reaction product of an organic
isocyanate and an organic amine, each having at least two
functional groups. Once these two ingredients are combined, the
polyurea is formed, and thus the ability to vary the physical
properties of the composition is limited. And, like polyurethanes,
polyureas are not completely comparable to ionomer resin golf balls
with respect to resilience or the rebound or damping behavior of
the golf ball cover. Moreover, golf ball components cast from
polyurethane or polyurea compositions involve complicated ratio and
dynamic mixing requirements, which adds to possible waste during
manufacturing if the requirements are not met.
[0009] Therefore, there remains a continuing need for golf ball
components that may be cast using a composition that solves the
problems associated with polyurethane and polyurea compositions
discussed above, e.g., resilience reduction and complicated ratio
and mixing requirements, while still obtaining the soft feel
provided by such compositions. In particular, it would be
advantageous to provide a composition formed from incorporating
aliphatic chemistries, however past efforts to make top quality
blemish free aliphatic golf ball covers with aliphatic chemistries
required elevated temperature post curing or delay times which were
unacceptable.
[0010] There is a need in making golf ball covers, for compositions
that contain aliphatic chemistries, but in a manner that does not
require the added curing times or the higher processing
temperature. The present invention describes such compositions and
the use of them in a variety of golf ball cover layers.
SUMMARY OF THE INVENTION
[0011] The present invention is directed to a golf ball including a
core and a cover, wherein the cover is cast from a castable
reactive aliphatic functional composition consisting essentially
of: a methylene dicyclohexyl diisocyanate based prepolymer; at
least one polyamine/polyamide functional component used as a
backbone of the prepolymer; a free isocyanate group; and a
curative. The polyamine/polyamide is formed from the condensation
reaction of a polyamine and a polyacid, with the equivalent ratio
of polyamine to polyacid ranges from 2:1 to 10:1, preferably the
ratio is 3:1, and more preferably 2:1. It is preferable that the
polyamine be a Jeffamine series D-2000. The polyacid can be chosen
from acids such as maleic, adipic, azelaic or sebacic. It is
preferable that the prepolymer be a polyurethane or urea.
DETAILED DESCRIPTION OF THE INVENTION
[0012] The present invention is directed to formulating techniques
that eliminate the need for a post cure or delay times when
utilizing aliphatic chemistries in golf ball covers. The main
inventive concept of the present invention is incorporating amide
linkages as the pre-polymer backbone or incorporating them into the
curing agent.
[0013] Typically, formulations are designed with concern for only
the physical properties of the finished materials. The present
invention not only formulates for material properties, but teaches
towards formulating for ease of material processing, by eliminating
the need for additional manufacturing steps to produce blemish-free
aliphatic golf ball covers. Utilizing aliphatic chemistries often
has required elevated temperature post curing which has been
eliminated herein by the present invention.
Compositions of the Invention
[0014] A polyamine/polyamide is formed by the condensation reaction
of a polyacid and a polyamine. The equivalent ration of polyamine
to polyacid ranges from 2:1 to 10:1, and a blend of at least two
polyacids and/or a blend of at least two polyamines can be used,
wherein one has a molecular weight greater than the other. Useful
polyamines include, but are not limited to, polyamines such as the
Jeffamine series from Huntsman. Polyacids useful for the present
invention include, but are not limited to, maleic acid, adipic
acid, azelaic acid, and sebacic acid. When the polyacid/polyamine
reaction is complete, it can be utilized as a curing agent or in
the backbone of an isocyanate based pre-polymer. Other methods of
producing polyamides known to those skilled in the art may also be
used in the present invention.
[0015] Previous attempts at molding defect free aliphatic cover
formulations have required additional process steps to the method
of the present invention. These steps have included: additional
curing time; elevated post cure times; and chilling of the golf
ball cores. It has been discovered that the incorporation of amide
linkages into the polymer eliminates the need for additional
process steps to produce defect free golf ball covers. The present
invention allows for the formulator to utilize aliphatic
chemistries that would otherwise be prohibited due to manufacturing
constraints. The ratio of polyamine/polyacid is the determining
factor when trying to balance both physical properties and ease of
processing of the formulation.
[0016] It should be understood that the examples below are for
illustrative purposes only. In no manner is the present invention
limited to the specific disclosures therein.
Conventional Aliphatic Cover Formulation
[0017] Pre-polymer: 1.0 eq. of Jeffamine D-2000 pre-polymer @ 6.4%
NCO
[0018] Curative: 0.95 eq. Clearlink 1000 and 3.5% HCC 19584 (white
dispersion)
Present Invention Example #1
[0019] Pre-polymer: Jeffamine D-2000/Adipic acid @ 3:1 ratio @
6.42% NCO
[0020] Curative: 0.95 eq. Clearlink 1000 and 3.5% HCC 19584 (white
dispersion)
Present Invention Example #2
[0021] Pre-polymer: Jeffamine D-2000/Adipic acid @ 2:1 ratio @ 6.4%
NCO
[0022] Curative: 0.95 eq. Clearlink 1000 and 3.5% HCC 19584 (white
dispersion)
Conventional Aliphatic Versus Present Invention and Effect on
Processing
TABLE-US-00001 [0023] Conventional Present invention Present
Invention Formulation Aliphatic # 1 Example # 1 Example # 2
Prepolymer DesW/D-2000 DesW/D-2000/Adipic Acid DesW/D-2000/Adipic
Acid @ 3:1 @ 2:1 Curative Clearlink 1000 Clearlink 1000 Clearlink
1000 Pre-polymer 140.degree. F. 140.degree. F. 140.degree. F.
Temperature Curative Room temperature Room temperature Room
temperature Temperature Mold Temperature 130.degree. F. 130.degree.
F. 130.degree. F. Core Temperature Room temperature Room
temperature Room temperature Post Cure 135.degree. F. None None
Temperature Post Cure Time 8 minutes None None
[0024] Jeffamine.RTM. D-2000 is a polyetheramine characterized by
repeating oxypropylene units in the backbone and is a difunctional,
primary amine with average molecular weight of about 2000. The
primary amine groups are located on secondary carbon atoms at the
end of the aliphatic polyether chains.
[0025] The data in the above chart shows the advantage of utilizing
polyamine/polyamide chemistries in the casting of aliphatic golf
ball covers. Through the incorporation of amide linkages into the
polymer, additional process steps such as post cure times and the
chilling of the cores have been eliminated.
[0026] The compositions of the invention may be used in cover
layers of a variety of golf ball constructions, e.g., one-piece,
two-piece, and multilayer balls.
[0027] Representative aliphatic and cycloaliphatic acids suitable
for use in this aspect of the invention include, but are not
limited to, sebacic acid, 1, 3 or 1,4-cyclohexane dicarboxylic
acid, adipic acid, glutaric acid, succinic acid, carbonic acid,
oxalic acid, itaconic acid, azelaic acid, diethylmalonic acid,
fumaric acid, citraconic acid, allylmalonate acid,
4-cyclohexene-1,2-dicarboxylate acid, pimelic acid, suberic acid,
2,5-diethyladipic acid, 2-ethylsuccinic acid, cyclopentane
dicarboxylic acid, 2,2,3,3 tetramethyl succinic acid,
decahydro-1,5-(or 2,6-) naphthylene dicarboxylic acid,
4,4'-bicyclohexyl dicarboxylic acid, 4,4'-methylenebis(cyclohexyl
carboxylic acid), 3,4-furan dicarboxylate, 1,1-cyclobutane
dicarboxylate, and mixtures thereof.
[0028] Additional materials other than the main components
discussed above may be added to the compositions of the invention
including, but not limited to, coloring agents or dyes, optical
brighteners, cross-linking agents, whitening agents such as
TiO.sub.2 and ZnO, UV absorbers, hindered amine light stabilizers,
de-foaming agents, processing aids, softening agents, plasticizers,
surfactants, impact modifiers, fillers, reinforcing materials,
catalysts, compatibilizers, fragrance components, antioxidants and
other conventional additives. Those of ordinary skill in the art
are aware of the purpose of these additives and the amounts that
should be employed to fulfill those purposes.
[0029] For example, fillers may be added to the compositions of the
invention to affect rheological and mixing properties, the specific
gravity (i.e., density-modifying fillers), the modulus, the tear
strength, reinforcement, and the like. The fillers are generally
inorganic, and suitable fillers include numerous metals, metal
oxides and salts, such as zinc oxide and tin oxide, as well as
barium sulfate, zinc sulfate, calcium carbonate, zinc carbonate,
barium carbonate, clay, tungsten, tungsten carbide, an array of
silicas, regrind (recycled core material typically ground to about
30 mesh particle), high-Mooney-viscosity rubber regrind (having a
Mooney viscosity of about 55 or greater), and mixtures thereof.
[0030] In addition, the compositions of the invention may contain
at least one light stabilizing component. As used herein, light
stabilizer may be understood to include hindered amine light
stabilizers, ultraviolet (UV) absorbers, and antioxidants. Addition
of UV absorbers and light stabilizers to any of the above
compositions may help to maintain the tensile strength, elongation,
and color stability, as well as prevent cover surface fractures due
to photodegradation. Suitable light stabilizers include, but are
not limited to, TINUVIN.RTM. 292, TINUVIN.RTM. 328, TINUVIN.RTM.
213, TINUVIN.RTM. 765, TINUVIN.RTM. 770 and TINUVIN.RTM. 622.
TINUVIN.RTM. products are available from Ciba Specialty Chemicals
of Tarrytown, N.Y.
[0031] Moreover, as discussed above, dyes, as well as optical
brighteners and fluorescent pigments may also be included in the
golf ball covers produced with polymers formed according to the
present invention. Such additional ingredients may be added in any
amounts that will achieve their desired purpose. For example, a
white dispersion may used in the compositions of the invention,
preferably in an amount of about 0.5 percent to about 10 percent by
weight of the composition. In one embodiment, the composition of
the invention includes about 2 percent to about 8 percent of white
dispersion by weight of the composition. In another embodiment, the
white dispersion is present in the composition in an amount of
about 3 percent to about 6 percent by weight of the composition. In
still another embodiment, the white dispersion is present in the
composition in an amount of about 3.5 percent to about 5 percent by
weight of the composition.
[0032] Furthermore, a stabilizing component may be included that is
a combination of polyamide and antioxidant. For example, U.S. Pat.
No. 3,896,078 discloses a suitable stabilizer for use in the
compositions of the invention, the entire disclosure of which is
incorporated by reference herein. In particular, such a stabilizing
component may be included in the composition in amounts providing
up to about 6.5 percent of amide linkages by weight of the
composition.
Golf Ball Construction
[0033] The compositions of the present invention may be used with
any type of ball construction. For example, one-piece, two-piece,
three-piece, and four-piece golf ball designs are contemplated by
the present invention. In addition, golf balls having double cores,
intermediate layer(s), and/or double covers are also useful with
the present invention. As known to those of ordinary skill in the
art, the type of golf ball constructed, i.e., double core, double
cover, and the like, depends on the type of performance desired of
the ball. As used herein, the term "layer" includes any generally
spherical portion of a golf ball, i.e., a golf ball core or center,
an intermediate layer, and/or a golf ball cover. As used herein,
the term "inner layer" refers to any golf ball layer beneath the
outermost structural layer of the golf ball. As used herein,
"structural layer" does not include a coating layer, top coat,
paint layer, or the like. As used herein, the term "multilayer"
means at least two layers.
[0034] As discussed, the golf balls of the invention include at
least one structural layer that includes compositions of the
invention. In addition, as discussed in more detail below, the golf
balls of the invention may include core layers, intermediate
layers, or cover layers formed from materials known to those of
skill in the art. These examples are not exhaustive, as skilled
artisans would be aware that a variety of materials might be used
to produce a golf ball of the invention with desired performance
properties.
Intermediate Layer(s)
[0035] As used herein, "intermediate layer" includes any layer
between the innermost layer of the golf ball and the outermost
layer of the golf ball. Therefore, intermediate layers may also be
referred to as outer core layers, inner cover layers, and the like.
When the golf ball of the present invention includes an
intermediate layer, this layer may be formed from the compositions
of the invention.
[0036] The intermediate layer may also be formed of conventional
materials known to those of ordinary skill in the art, including
various thermoset and thermoplastic materials, as well as blends
thereof. For example, the intermediate layer may be formed, at
least in part, from one or more homopolymeric or copolymeric
materials, such as vinyl resins, low and high acid ionomer resins,
polyolefins, polyurethanes, polyureas, polyamides, acrylic resins,
olefinic thermoplastic rubbers, block copolymers of styrene and
butadiene, isoprene or ethylene-butylene rubber,
copoly(ether-amide), polyphenylene oxide resins, thermoplastic
polyesters, ethylene, propylene, 1-butene or 1-hexene based
homopolymers or copolymers, and the like.
[0037] The intermediate layer may also be formed from highly
neutralized polymers such as those disclosed U.S. Pat. Nos.
6,565,455 and 6,565,456, which are incorporated herein in their
entirety by express reference thereto; grafted and non-grafted
metallocene catalyzed polyolefins and polyamides, polyamide/ionomer
blends, and polyamide/nonionomer blends, such as those disclosed in
U.S. Pat. No. 6,800,690, which is incorporated by reference herein
in its entirety; among other polymers. Examples of other suitable
intermediate layer materials include blends of some of the above
materials, such as disclosed in U.S. Pat. No. 5,688,181, and of
which the entire disclosure is incorporated by reference
herein.
[0038] The intermediate layer may also be a moisture barrier layer,
such as described in U.S. Pat. No. 5,820,488, and which is
incorporated in its entirety by reference herein.
Cover Layer(s)
[0039] The cover provides the interface between the ball and a
club. As used herein, the term "cover" means the outermost portion
of a golf ball. A cover typically includes at least one layer and
may contain indentations such as dimples and/or ridges. Paints
and/or laminates are typically disposed about the cover to protect
the golf ball during use thereof. The cover may include a plurality
of layers, e.g., an inner cover layer disposed about a golf ball
center and an outer cover layer formed thereon.
[0040] Inner and/or outer cover layers may be formed from the
compositions of the invention. Alternatively, both the inner and/or
outer cover layers of golf balls of the present invention may be
formed of polyurea, polyurethane, or mixtures thereof, as disclosed
in U.S. Pat. Nos. 6,835,794 and 7,041,770. The entire disclosures
of these publications are incorporated by reference herein.
[0041] In addition, cover layers may also be formed of one or more
homopolymeric or copolymeric materials, such as vinyl resins,
polyolefins, conventional polyurethanes and polyureas, such as the
ones disclosed in U.S. Pat. Nos. 5,334,673, and 5,484,870,
polyamides, acrylic resins and blends of these resins with poly
vinyl chloride, elastomers, and the like, thermoplastic urethanes,
olefinic thermoplastic rubbers, block copolymers of styrene and
butadiene, polyphenylene oxide resins or blends of polyphenylene
oxide with high impact polystyrene, thermoplastic polyesters,
ethylene, propylene, 1-butene or 1-hexane based homopolymers or
copolymers including functional monomers, methyl acrylate, methyl
methacrylate homopolymers and copolymers, low acid ionomers, high
acid ionomers, highly neutralized ionomers, alloys, and mixtures
thereof.
[0042] Additional materials may be included in the core,
intermediate layer, and/or cover layer compositions outlined above.
For example, catalysts, coloring agents, optical brighteners,
cross-linking agents, whitening agents such as TiO.sub.2 and ZnO,
UV absorbers, hindered amine light stabilizers, defoaming agents,
processing aids, surfactants, and other conventional additives may
be added to the cover layer compositions of the invention. In
addition, antioxidants, stabilizers, softening agents,
plasticizers, including internal and external plasticizers, impact
modifiers, foaming agents, density-adjusting fillers, reinforcing
materials, and compatibilizers may also be added to any of the
cover layer compositions. Those of ordinary skill in the art should
be aware of the requisite amount for each type of additive to
realize the benefits of that particular additive.
Methods for Forming Golf Ball Components
[0043] The golf balls of the invention may be formed using a
variety of application techniques such as compression molding, flip
molding, injection molding, retractable pin injection molding,
reaction injection molding (RIN), reinforced reaction injection
molding (RRIM), retractable pin injection molding (RPIM), casting,
vacuum forming, powder coating, flow coating, spin coating,
dipping, spraying, and the like depending on the materials used for
a specific component. For example, the compositions of the
invention are particular useful in injection molding and extrusion
applications. Thus, golf ball components including the compositions
of the invention may be formed by injection molding and the
like.
[0044] Although the molding method for the present invention is
casting, one skilled in the art, however, would appreciate that the
molding method used may be determined at least partially by the
properties of the composition used to form the particular golf ball
component. For example, casting or RIM, may be preferred when the
material is thermoset, whereas compression molding or injection
molding may be preferred for thermoplastic compositions.
Compression molding, however, may also be used for thermoset inner
ball materials. For example, when cores are formed from a thermoset
material, compression molding is a particularly suitable method of
forming the core, whereas when the cores are formed of a
thermoplastic material, the cores may be injection molded. In
addition, the intermediate layer may also be formed from using any
suitable method known to those of ordinary skill in the art. For
instance, an intermediate layer may be formed by blow molding and
covered with a dimpled cover layer formed by injection molding,
compression molding, casting, vacuum forming, powder coating, and
the like.
Dimples
[0045] The golf balls of the invention are preferably designed with
certain flight characteristics in mind. The use of various dimple
patterns and profiles provides a relatively effective-way to modify
the aerodynamic characteristics of a golf ball. As such, the manner
in which the dimples are arranged on the surface of the ball can be
by any available method. For instance, the ball may have an
icosahedron-based pattern, such as described in U.S. Pat. No.
4,560,168, or an octahedral-based dimple patterns as described in
U.S. Pat. No. 4,960,281. Alternatively, the dimple pattern can be
arranged according to phyllotactic patterns, such as described in
U.S. Pat. No. 6,338,684, or a tubular lattice pattern, such as the
one disclosed in U.S. Pat. No. 6,290,615, the disclosures of which
are incorporated herein in their entirety.
Golf Ball Post-Processing
[0046] The golf balls of the present invention may be painted,
coated, or surface treated for further benefits. For example, a
golf ball of the invention may be treated with a base resin paint
composition or the cover composition may contain certain additives
to achieve a desired color characteristic. In one embodiment, the
golf ball cover composition contains a fluorescent whitening agent
to provide improved weather resistance and brightness.
[0047] Protective and decorative coating materials, as well as
methods of applying such materials to the surface of a golf ball
cover are well known in the golf ball art. Generally, such coating
materials comprise urethanes, urethane hybrids, epoxies, polyesters
and acrylics. If desired, more than one coating layer can be used.
The coating layer(s) may be applied by any suitable method known to
those of ordinary skill in the art. For example, the coating
layer(s) may be applied to the golf ball cover by an in-mold
coating process, such as described in U.S. Pat. No. 5,849,168,
which is incorporated in its entirety by reference herein. The
coating layer may have a thickness of about 0.004 inches or less,
more preferably about 0.002 inches or less.
[0048] In addition, the golf balls of the invention may be painted
or coated with an ultraviolet curable/treatable ink, by using the
methods and materials disclosed in U.S. Pat. Nos. 6,500,495,
6,248,804, and 6,099,415, the entire disclosures of which are
incorporated by reference herein.
[0049] Furthermore, trademarks or other indicia may be stamped,
i.e., pad-printed, on the outer surface of the ball cover, and the
stamped outer surface is then treated with at least one clear coat
to give the ball a glossy finish and protect the indicia stamped on
the cover.
[0050] The golf balls of the invention may also be subjected to dye
sublimation, wherein at least one golf ball component is subjected
to at least one sublimating ink that migrates at a depth into the
outer surface and forms an indicia. The at least one sublimating
ink preferably includes at least one of an azo dye, a
nitroarylamine dye, or an anthraquinone dye as disclosed in U.S.
Pat. No. 6,935,240, the entire disclosure of which is incorporated
by reference herein.
[0051] Laser marking of a selected surface portion of a golf ball
causing the laser light-irradiated portion to change color is also
contemplated for use with the present invention. U.S. Pat. Nos.
5,248,878 and 6,075,223 generally disclose such methods, the entire
disclosures of which are incorporated by reference herein. In
addition, the golf balls may be subjected to ablation, i.e.,
directing a beam of laser radiation onto a portion of the cover,
irradiating the cover portion, wherein the irradiated cover portion
is ablated to form a detectable mark, wherein no significant
discoloration of the cover portion results therefrom. Ablation is
discussed in U.S. Pat. No. 6,462,303, which is incorporated in its
entirety by reference herein.
Golf Ball Properties
[0052] The properties such as hardness, modulus, core diameter, and
layer thickness of the golf balls of the present invention have
been found to effect play characteristics such as spin, initial
velocity and feel of the present golf balls. For example, the
flexural and/or tensile modulus of the intermediate layer are
believed to have an effect on the "feel" of the golf balls of the
present invention. It should be understood that the ranges herein
are meant to be intermixed with each other, i.e., the low end of
one range may be combined with a high end of another range.
Component Dimensions
[0053] Dimensions of golf ball components, i.e., thickness and
diameter, may vary depending on the desired properties. For the
purposes of the invention, any layer thickness may be employed.
Non-limiting examples of the various embodiments outlined above are
provided here with respect to layer dimensions.
[0054] The present invention relates to golf balls of any size.
While USGA specifications limit the size of a competition golf ball
to more than 1.68 inches in diameter, golf balls of any size can be
used for leisure golf play. The preferred diameter of the golf
balls is from about 1.68 inches to about 1.8 inches. The more
preferred diameter is from about 1.68 inches to about 1.76 inches.
A diameter of from about 1.68 inches to about 1.74 inches is most
preferred, however diameters anywhere in the range of from 1.7 to
about 1.95 inches can be used. Preferably, the overall diameter of
the core and all intermediate layers is about 80 percent to about
98 percent of the overall diameter of the finished ball.
[0055] The core may have a diameter ranging from about 0.09 inches
to about 1.65 inches. In one embodiment, the diameter of the core
of the present invention is about 1.2 inches to about 1.630 inches.
In another embodiment, the diameter of the core is about 1.3 inches
to about 1.6 inches, preferably from about 1.39 inches to about 1.6
inches, and more preferably from about 1.5 inches to about 1.6
inches. In yet another embodiment, the core has a diameter of about
1.55 inches to about 1.65 inches.
[0056] The core of the golf ball may also be extremely large in
relation to the rest of the ball. For example, in one embodiment,
the core makes up about 90 percent to about 98 percent of the ball,
preferably about 94 percent to about 96 percent of the ball. In
this embodiment, the diameter of the core is preferably about 1.54
inches or greater, preferably about 1.55 inches or greater. In one
embodiment, the core diameter is about 1.59 inches or greater. In
another embodiment, the diameter of the core is about 1.64 inches
or less.
[0057] When the core includes an inner core layer and an outer core
layer, the inner core layer is preferably about 0.9 inches or
greater and the outer core layer preferably has a thickness of
about 0.1 inches or greater. In one embodiment, the inner core
layer has a diameter from about 0.09 inches to about 1.2 inches and
the outer core layer has a thickness from about 0.1 inches to about
0.8 inches. In yet another embodiment, the inner core layer
diameter is from about 0.095 inches to about 1.1 inches and the
outer core layer has a thickness of about 0.20 inches to about 0.03
inches.
[0058] The cover typically has a thickness to provide sufficient
strength, good performance characteristics, and durability. The
thickness of the outer cover layer may be from about 0.005 inches
to about 0.100 inches, preferably about 0.007 inches to about 0.035
inches. In one embodiment, the cover thickness is from about 0.02
inches to about 0.35 inches. In another embodiment, the cover
preferably has a thickness of about 0.02 inches to about 0.12
inches, preferably about 0.1 inches or less, more preferably about
0.07 inches or less. In yet another embodiment, the outer cover has
a thickness from about 0.02 inches to about 0.07 inches. In still
another embodiment, the cover thickness is about 0.05 inches or
less, preferably from about 0.02 inches to about 0.05 inches. For
example, the outer cover layer may be between about 0.02 inches and
about 0.045 inches, preferably about 0.025 inches to about 0.04
inches thick. In one embodiment, the outer cover layer is about
0.03 inches thick.
[0059] The range of thicknesses for an intermediate layer of a golf
ball is large because of the vast possibilities when using an
intermediate layer, i.e., as an outer core layer, an inner cover
layer, a wound layer, a moisture/vapor barrier layer. When used in
a golf ball of the invention, the intermediate layer, or inner
cover layer, may have a thickness about 0.3 inches or less. In one
embodiment, the thickness of the intermediate layer is from about
0.002 inches to about 0.1 inches, preferably about 0.01 inches or
greater. In one embodiment, the thickness of the intermediate layer
is about 0.09 inches or less, preferably about 0.06 inches or less.
In another embodiment, the intermediate layer thickness is about
0.05 inches or less, more preferably about 0.01 inches to about
0.045 inches. In one embodiment, the intermediate layer, thickness
is about 0.02 inches to about 0.04 inches. In another embodiment,
the intermediate layer thickness is from about 0.025 inches to
about 0.035 inches. In yet another embodiment, the thickness of the
intermediate layer is about 0.035 inches thick. In still another
embodiment, the inner cover layer is from about 0.03 inches to
about 0.035 inches thick. Varying combinations of these ranges of
thickness for the intermediate and outer cover layers may be used
in combination with other embodiments described herein.
[0060] The ratio of the thickness of the intermediate layer to the
outer cover layer is preferably about 10 or less, preferably from
about 3 or less. In another embodiment, the ratio of the thickness
of the intermediate layer to the outer cover layer is about 1 or
less.
Hardness
[0061] Most golf balls consist of layers having different levels of
hardness, e.g., hardness gradients, to achieve desired performance
characteristics. The present invention contemplates golf balls
having hardness gradients between layers, as well as those golf
balls with layers having the same hardness.
[0062] It should be understood, especially to one of ordinary skill
in the art, that there is a fundamental difference between
"material hardness" and "hardness, as measured directly on a golf
ball." Material hardness is defined by the procedure set forth in
ASTM-D2240 and generally involves measuring the hardness of a flat
"slab" or "button" formed of the material of which the hardness is
to be measured. Hardness, when measured directly on a golf ball (or
other spherical surface) is a completely different measurement and,
therefore, results in a different hardness value. This difference
results from a number of factors including, but not limited to,
ball construction (i.e., core type, number of core and/or cover
layers, etc.), ball (or sphere) diameter, and the material
composition of adjacent layers. It should also be understood that
the two measurement techniques are not linearly related and,
therefore, one hardness value cannot easily be correlated to the
other.
[0063] The cores of the present invention may have varying grades
of hardness depending on the particular golf ball construction. In
one embodiment, the core hardness is at least about 15 Shore A,
preferably about 30 Shore A, as measured on a formed sphere. In
another embodiment, the core has a hardness of about 50 Shore A to
about 90 Shore D. In yet another embodiment, the hardness of the
core is about 80 Shore D or less. Preferably, the core has a
hardness about 30 to about 65 Shore D, and more preferably, the
core has a hardness about 35 to about 60 Shore D.
[0064] The intermediate layer(s) of the present invention may also
vary in hardness depending on the specific construction of the
ball. In one embodiment, the hardness of the intermediate layer is
about 30 Shore D or greater. In another embodiment, the hardness of
the intermediate layer is about 90 Shore D or less, preferably
about 80 Shore D or less, and more preferably about 70 Shore D or
less. In yet another embodiment, the hardness of the intermediate
layer is about 50 Shore D or greater, preferably about 55 Shore D
or greater. In one embodiment, the intermediate layer hardness is
from about 55 Shore D to about 65 Shore D. The intermediate layer
may also be about 65 Shore D or greater.
[0065] When the intermediate layer is intended to be harder than
the core layer, then the ratio of the intermediate layer hardness
to the core hardness is preferably about 2 or less. In one
embodiment, the ratio is about 1.8 or less. In yet another
embodiment, the ratio is about 1.3 or less.
[0066] As with the core and intermediate layers, the cover hardness
may vary depending on the construction and desired characteristics
of the golf ball. The ratio of cover hardness to inner ball
hardness is a primary variable used to control the aerodynamics of
a ball and, in particular, the spin of a ball. In general, the
harder the inner ball, the greater the driver spin and the softer
the cover, the greater the driver spin.
[0067] For example, when the intermediate layer is intended to be
the hardest point in the ball, e.g., about 50 Shore D to about 75
Shore D, the cover material may have a hardness of about 20 Shore D
or greater, preferably about 25 Shore D or greater, and more
preferably about 30 Shore D or greater, as measured on the slab. In
another embodiment, the cover itself has a hardness of about 30
Shore D or greater. In particular, the cover may be from about 30
Shore D to about 70 Shore D. In one embodiment, the cover has a
hardness of about 40 Shore D to about 65 Shore D, and in another
embodiment, about 40 Shore to about 55 Shore D. In another aspect
of the invention, the cover has a hardness less than about 45 Shore
D, preferably less than about 40 Shore D, and more preferably about
25 Shore D to about 40 Shore D. In one embodiment, the cover has a
hardness from about 30 Shore D to about 40 Shore D.
[0068] In this embodiment when the outer cover layer is softer than
the intermediate layer or inner cover layer, the ratio of the Shore
D hardness of the outer cover material to the intermediate layer
material is about 0.8 or less, preferably about 0.75 or less, and
more preferably about 0.7 or less. In another embodiment, the ratio
is about 0.5 or less, preferably about 0.45 or less.
[0069] In yet another embodiment, the ratio is about 0.1 or less
when the cover and intermediate layer each have a hardness that are
substantially the same. When the hardness differential between the
cover layer and the intermediate layer is not intended to be as
significant, the cover may have a hardness of about 55 Shore D to
about 65 Shore D. In this embodiment, the ratio of the Shore D
hardness of the outer cover to the intermediate layer is about 1.0
or less, preferably about 0.9 or less.
[0070] In another embodiment, the cover layer is harder than the
intermediate layer. In this design, the ratio of Shore D hardness
of the cover layer to the intermediate layer is about 1.33 or less,
preferably from about 1.14 or less.
Compression
[0071] Compression values are dependent on the diameter of the
component being measured. Atti compression is typically used to
measure the compression of a golf ball. As used herein, the terms
"Atti compression" or "compression" are defined as the deflection
of an object or material relative to the deflection of a calibrated
spring, as measured with an Atti Compression Gauge, that is
commercially available from Atti Engineering Corp. of Union City,
N.J.
[0072] The Atti compression of the core, or portion of the core, of
golf balls prepared according to the invention is preferably less
than about 80, more preferably less than about 75. In another
embodiment, the core compression is from about 40 to about 80,
preferably from about 50 to about 70. In yet another embodiment,
the core compression is preferably below about 50, and more
preferably below about 25. In an alternative, low compression
embodiment, the core has a compression less than about 20, more
preferably less than about 10, and most preferably, 0. As known to
those of ordinary skill in the art, however, the cores generated
according to the present invention may be below the measurement of
the Atti Compression Gauge.
[0073] In one embodiment, golf balls of the invention preferably
have an Atti compression of about 55 or greater, preferably from
about 60 to about 120. In another embodiment, the Atti compression
of the golf balls of the invention is at least about 40, preferably
from about 50 to 120, and more preferably from about 60 to 100. In
yet another embodiment, the compression of the golf balls of the
invention is about 75 or greater and about 95 or less. For example,
a preferred golf ball of the invention may have a compression from
about 80 to about 95.
Initial Velocity and COR
[0074] There is currently no USGA limit on the COR of a golf ball,
but the initial velocity of the golf ball cannot exceed 250.+-.5
feet/second (ft/s). Thus, in one embodiment, the initial velocity
is about 245 ft/s or greater and about 255 ft/s or greater. In
another embodiment, the initial velocity is about 250 ft/s or
greater. In one embodiment, the initial velocity is about 253 ft/s
to about 254 ft/s. In yet another embodiment, the initial velocity
is about 255 ft/s. While the current rules on initial velocity
require that golf ball manufacturers stay within the limit, one of
ordinary skill in the art would appreciate that the golf ball of
the invention would readily convert into a golf ball with initial
velocity outside of this range. For example, a golf ball of the
invention may be designed to have an initial velocity of about 220
ft/s or greater, preferably about 225 ft/s or greater.
[0075] As a result, of the initial velocity limitation set forth by
the USGA, the goal is to maximize COR without violating the 255
ft/s limit. The COR of a ball is measured by taking the ratio of
the outbound or rebound velocity to the incoming or inbound
velocity. In a one-piece solid golf ball, the COR will depend on a
variety of characteristics of the ball, including its composition
and hardness. For a given composition, COR will generally increase
as hardness is increased. In a two-piece solid golf ball, e.g., a
core and a cover, one of the purposes of the cover is to produce a
gain in COR over that of the core. When the contribution of the
core to high COR is substantial, a lesser contribution is required
from the cover. Similarly, when the cover contributes substantially
to high COR of the ball, a lesser contribution is needed from the
core.
[0076] The present invention contemplates golf balls having CORs
from about 0.700 to about 0.850 at an inbound velocity of about 125
ft/sec. In one embodiment, the COR is about 0.750 or greater,
preferably about 0.780 or greater. In another embodiment, the ball
has a COR of about 0.800 or greater. In yet another embodiment, the
COR of the balls of the invention is about 0.800 to about
0.815.
Spin Rate
[0077] As known to those of ordinary skill in the art, the spin
rate of a golf ball will vary depending on the golf ball
construction. In a multilayer ball, e.g., a core, an intermediate
layer, and a cover, wherein the cover is formed from the
compositions of the invention, the spin rate of the ball off a
driver ("driver spin rate") may be 1500 rpm or greater. In one
embodiment, the driver spin rate is about 2000 rpm to about 3500
rpm. In another embodiment, the driver spin rate is about 2200 rpm
to about 3400 rpm. In still another embodiment, the driver spin
rate may be less than about 1500 rpm.
[0078] Two-piece balls made according to the invention may also
have driver spin rates of 1500 rpm and greater. In one embodiment,
the driver spin rate is about 2000 rpm to about 3300 rpm. Wound
balls made according to the invention preferably have similar spin
rates.
[0079] Methods of determining the spin rate should be well
understood by those of ordinary skill in the art. Examples of
methods for determining the spin rate are disclosed in U.S. Pat.
Nos. 6,500,073, 6,488,591, 6,286,364, and 6,241,622, which are
incorporated by reference herein in their entirety.
[0080] The invention described and claimed herein is not to be
limited in scope by the specific embodiments herein disclosed,
since these embodiments are intended as illustrations of several
aspects of the invention. Any equivalent embodiments are intended
to be within the scope of this invention. All patents and patent
applications cited in the foregoing text are expressly incorporate
herein by reference in their entirety.
* * * * *