U.S. patent application number 12/752423 was filed with the patent office on 2011-10-06 for golf ball comprising renewable resource component.
Invention is credited to Kevin M. Harris, Murali Rajagopalan.
Application Number | 20110244984 12/752423 |
Document ID | / |
Family ID | 44710279 |
Filed Date | 2011-10-06 |
United States Patent
Application |
20110244984 |
Kind Code |
A1 |
Harris; Kevin M. ; et
al. |
October 6, 2011 |
GOLF BALL COMPRISING RENEWABLE RESOURCE COMPONENT
Abstract
The invention is directed to a golf ball comprising a core and a
cover, wherein at least one of the core and the cover comprises
about 10 wt % or greater of a renewable polymer composition
comprising an ultra high molecular weight polyhydroxyalkanoate
compound having the formula:
--OCR.sub.1R.sub.2(CR.sub.3R.sub.4).sub.nCO-- wherein n is an
integer, and wherein R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are
selected from the group comprising saturated and unsaturated
hydrocarbon radicals, halo- and hydroxy-substituted radicals,
hydroxy radicals, halogen radicals; nitrogen-substituted radicals,
oxygen-substituted radicals, or hydrogen atoms. The ultra high
molecular weight polyhydroxyalkanoate compound is coupled with the
at least one non renewable polymer composition by at least one of
dipole-dipole coupling, ion-dipole coupling, ion-ion coupling and
coupling via hydrogen bonding. In one embodiment, the golf ball
comprises about 90 wt % or less of the non renewable polymer
composition. The golf ball may also comprise an intermediate layer
disposed about the core and adjacent the cover, wherein at least
one of the core, the cover and the intermediate layer comprises the
renewable polymer composition. The at least one of the core, the
cover and the intermediate layer may comprise a hardness of from
about 50 Shore C to about 90 Shore C.
Inventors: |
Harris; Kevin M.; (New
Bedford, MA) ; Rajagopalan; Murali; (South Dartmouth,
MA) |
Family ID: |
44710279 |
Appl. No.: |
12/752423 |
Filed: |
April 1, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12752378 |
Apr 1, 2010 |
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12752423 |
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Current U.S.
Class: |
473/372 ;
473/371 |
Current CPC
Class: |
A63B 37/0024 20130101;
A63B 37/0039 20130101; A63B 37/0075 20130101; A63B 37/0051
20130101; A63B 37/0003 20130101 |
Class at
Publication: |
473/372 ;
473/371 |
International
Class: |
A63B 37/00 20060101
A63B037/00 |
Claims
1. A golf ball comprising a core, a cover, and an intermediate
layer disposed about the core and adjacent the cover, wherein at
least one of the core, the cover and the intermediate layer
comprises: about 10 wt % or greater of a renewable polymer
composition comprising an ultra high molecular weight
polyhydroxyalkanoate compound having the formula:
--OCR.sub.1R.sub.2(CR.sub.3R.sub.4).sub.nCO-- wherein n is an
integer, and wherein R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are
selected from the group comprising saturated and unsaturated
hydrocarbon radicals, halo- and hydroxy-substituted radicals,
hydroxy radicals, halogen radicals; nitrogen-substituted radicals,
oxygen-substituted radicals, or hydrogen atoms; about 90 wt % or
less of a non renewable polymer composition; wherein the ultra high
molecular weight polyhydroxyalkanoate compound is coupled with the
at least one non renewable polymer composition by at least one of
dipole-dipole coupling, ion-dipole coupling, ion-ion coupling and
coupling via hydrogen bonding; and wherein the at least one of the
core, the cover and the intermediate layer comprises a hardness of
from about 50 Shore C to about 90 Shore C.
2. The golf ball of claim 1, wherein the ultra high molecular
weight polyhydroxyalkanoate compound comprises a molecular weight
of about 60,000 grams/mole or greater.
3. The golf ball of claim 1, wherein the at least one of the core
and the cover comprises about 5 wt % or greater of the ultra high
molecular weight polyhydroxyalkanoate compound.
4. The golf ball of claim 1, wherein the at least one of the core
and the cover comprises about 5 wt % or greater of the renewable
polymer composition.
5. The golf ball of claim 1, wherein the renewable polymer
composition comprises about 5 wt % or greater of the ultra high
molecular weight polyhydroxyalkanoate compound.
6. The golf ball of claim 1, wherein the ultra high molecular
weight polyhydroxyalkanoate compound is selected from the group
comprising homopolymers of polyhydroxyalkanoate and
polyhydroxybutyrate; a copolymer of hydroxybutyric acid and
hydroxyvaleric acid; a copolymer of 3-hydroxybutyric acid and
4-hydroxybutyric acid; polyhydroxyoctanoate; a copolymer of
4-hydroxybutyric and 4-hydroxyhexanoic acid; a copolymer of
4-hydroxybutyric acid and 4-hydroxyoctanoic acid; a copolymer of
3-hydroxyoctanoic acid with 3-hydroxybutryic acid; a copolymer of
3-hydroxyhexanoic acid and 3-hydroxybutyric acid; a copolymer
containing hydroxyoctonate groups randomly distributed through the
polymer chain and combinations thereof.
7. The golf ball of claim 1, wherein the ultra high molecular
weight polyhydroxyalkanoate compound further comprises end chain
functionalities selected from the group comprising vinyl,
carboxylic acid, carboxylic acid ester, anhydride, maleate, malic
acid, fumaric acid, acetate; butyrate, propanoate, primary alcohol,
secondary alcohol, tertiary alcohol, amide, and polyhydric
alcohol.
8. The golf ball of claim 1, wherein R.sub.1, R.sub.2, R.sub.3 and
R.sub.4 are substantially similar.
9. The golf ball of claim 1, wherein R.sub.1, R.sub.2, R.sub.3 and
R.sub.4 are different.
10. The golf ball of claim 1, wherein n=500 or greater.
11. The golf ball of claim 1, wherein the core comprises a hardness
of from about 30 Shore D to about 50 Shore D.
12. The golf ball of claim 1, wherein the cover comprises a
hardness of from about 40 Shore D to about 70 Shore D.
13. The golf ball of claim 1, further comprising at least one
renewable resource selected from the group comprising lignin, crop
oils, grains, plant derived glucose, yeast, fungi, vegetable oils,
canola oils, corn oils, flax, cellulose, fatty acids, animal fats,
tallow oils, fish oils, wood resins, tannis, polysaccharides, soy
protein, starch, polyesters, polylactic acids, triglycerides, homo-
and copolymers of polyhydroxyalkanoates.
14. The golf ball of claim 1, wherein the ultra high molecular
weight polyhydroxyalkanoate compound is formed from at least one of
monomeric units and oligomeric units selected from the group
comprising hydroxybutyrate, hydroxyvalerate, hydroxyhexanoate,
hydroxyheptanoate, hydroxyoctanoate, hydroxynonanoate,
hydroxydecanoate, hydroxyundecanoate, and hydroxydodecanoate and
blends thereof.
15. The golf ball of claim 1, wherein the ultra high molecular
weight polyhydroxyalkanoate compound is formed from at least one of
monomeric derivatives and oligomeric derivatives selected from the
group comprising 2-hydroxyacids, 3-hydroxyacids, 4-hydroxyacids,
5-hydroxyacids, p-lactic acid, and p-glycolic acid and blends there
of.
16. The golf ball of claim 1, wherein the non renewable polymer
composition comprises a synthetic polymer selected from homo- and
copolymers of polyolefin, polyester, polycarbonate, polyamide,
polyurethane, polyacrylic, polyimide, epoxy, thermoplastic
elastomers and combinations thereof.
17. The golf ball of claim 1, wherein the at least one of the core
and the cover further comprises at least one softening agent
selected from the group comprising alkyl acrylate, methacrylate,
glycidyl acrylate, and glycidyl methacrylate.
18. The golf ball of claim 1, wherein the at least one of the core
and the cover further comprises a stiffening/density adjusting
agent selected from the group comprising zinc oxide, barium
sulfate, tungsten, tungsten oxide, tungsten carbide, glass spheres,
carbon or glass reinforced polymers or composites, carbon
nanotubes, and blends thereof.
19. The golf ball of claim 1, wherein the renewable polymer
composition further comprises a cation selected from the group
comprising Li, Na, K, Cs, Mg, Ca, Ba, Mn, Zn, Cs, Zr, Ti, W, and
Al.
20. The golf ball of claim 1, further comprising an ester
compatibilizer selected from the group comprising a glycidyl ester,
a maleic ester and an oligomeric ester.
21. The golf ball of claim 20, wherein the oligomeric ester is
selected from the group comprising poly(1,3-butylene
glycol-co-1,2-propylene glycol adipic acid) terminated with
2-ethylhexanol, poly(neopentyl glycol-co-1,4-butylene glycol adipic
acid) terminated with 2-ethylhexanol, poly(1,3-butylene glycol
adipic acid) unterminated, poly(1,3-butylene glycol adipic acid)
unterminated, poly(1,2-propylene glycol adipic acid-co-phthahic
acid) terminated with 2-ethylhexanol, poly(neopentyl glycol adipic
acid) terminated with 2-ethylhexanol, poly(1,2-propylene glycol
adipic acid-co-phthalic acid) terminated with 2-ethylhexanol,
poly(1,2-propylene glycol-co-1,4-butylene glycol adipic acid)
terminated with 2 ethylhexanol, poly(1,3-butylene glycol adipic
acid) terminated with mixed fatty acids, poly(1,2-propylene glycol
adipic acid) terminated with 2-ethylhexanol, poly(1,2-propylene
glycol-co-1,4-butylene glycol adipic acid) terminated with
2-ethylhexanol, poly(1,4-butylene glycol adipic acid), or
poly(1,4-butylene glycol-co-ethylene glycol adipic acid).
22. The golf ball of claim 1, comprising a blended composition
comprising the renewable polymer composition and at least one
thermoplastic material selected from the group comprising ethylene
based ionomers, highly neutralized polymers, polyester-ether
elastomers, polyester-ester elastomers, polyether-amide elastomers,
polyester-amide elastomers, polyurethane elastomers, thermoplastic
vulcanized materials, EPDM rubber, EPR rubber, SEBS rubber,
copolymers of ethylene-alkyl acrylates, copolymers of
methacrylates, glycidyl acrylate copolymers, methacrylate
copolymers, maleic anhydride grafted homopolymers, maleic anhydride
grafted copolymers and polycaprolactone.
23. The golf ball of claim 22, wherein the blended composition
comprises from about 50 wt % to about 95 wt % of the at least one
thermoplastic compound.
24. A golf ball comprising a core, a cover, and an intermediate
layer disposed about the core and adjacent the cover, wherein at
least one of the core, the cover and the intermediate layer
comprises: about 10 wt % or greater of a renewable polymer
composition comprising an ultra high molecular weight
polyhydroxyalkanoate compound having the formula:
--OCR.sub.1R.sub.2(CR.sub.3R.sub.4).sub.nCO-- wherein n is an
integer, and wherein R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are
selected from the group comprising saturated and unsaturated
hydrocarbon radicals, halo- and hydroxy-substituted radicals,
hydroxy radicals, halogen radicals; nitrogen-substituted radicals,
oxygen-substituted radicals, or hydrogen atoms; about 90 wt % or
less of a non renewable polymer composition; and wherein the ultra
high molecular weight polyhydroxyalkanoate compound and the at
least one non renewable polymer composition are coupled.
25. A golf ball comprising a core, a cover, and an intermediate
layer disposed about the core and adjacent the cover, wherein at
least one of the core, the cover and the intermediate layer
comprises: about 10 wt % or greater of a renewable polymer
composition comprising an ultra high molecular weight
polyhydroxyalkanoate compound having the formula:
--OCR.sub.1R.sub.2(CR.sub.3R.sub.4).sub.nCO-- wherein n is an
integer, and wherein R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are
selected from the group comprising saturated and unsaturated
hydrocarbon radicals, halo- and hydroxy-substituted radicals,
hydroxy radicals, halogen radicals; nitrogen-substituted radicals,
oxygen-substituted radicals, or hydrogen atoms; about 90 wt % or
less of a non renewable polymer composition; wherein the ultra high
molecular weight polyhydroxyalkanoate compound is associated with
the at least one non renewable polymer composition by at least one
of dipole-dipole interaction, ion-dipole interaction, ion-ion
interaction and hydrogen bonding; and wherein the at least one of
the core, the cover and the intermediate layer comprises a hardness
of from about 50 Shore C to about 90 Shore C.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of co-pending U.S. patent
application Ser. No. 12/752,378, filed Apr. 1, 2010, which is
incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The invention relates to a golf ball including a renewable
resource component comprising a biodegradable composition in at
least one of the golf ball core (having one or more layers),
intermediate layer(s) and cover layer(s). The resulting golf ball
possesses desirable playing characteristics such as high
resiliency, sustained impact durability, and soft feel, meanwhile
protecting the environment over an extended period of time by being
decomposable.
BACKGROUND OF THE INVENTION
[0003] Golf balls are generally divided into two classes: solid and
wound. Solid golf balls include a solid core of one or more layers,
a cover of one or more layers, and optionally one or more
intermediate layers. Wound golf balls typically include a solid,
hollow, or fluid-filled center, surrounded by tensioned elastomeric
material, and a cover. Solid golf balls, as compared with wound
balls, are more durable and resilient, providing better distance
than wound balls due to their higher initial velocity upon impact
with a club face. Meanwhile, the wound construction provides a
softer "feel", lower compression and higher spin
rate--characteristics often preferred by accomplished golfers who
are able to control the ball's flight and positioning.
[0004] By altering solid golf ball construction and composition,
manufacturers can vary a wide range of playing characteristics such
as resilience, durability, spin, and "feel", optimizing each
according to various playing abilities and achieving a solid golf
ball possessing feel characteristics more like their wound
predecessors. For example, by shifting the density (the weight or
mass of the golf ball) toward the center of the ball, the moment of
inertia of the golf ball can be reduced, thereby increasing the
initial spin rate of the ball as it leaves the golf club head as a
result of the higher resistance from the golf ball's moment of
inertia.
[0005] In this regard, core is the "engine" of the golf ball when
hit with a club head. That is, it is the spring of the ball and its
principal source of resiliency. Meanwhile, the intermediate layers
based on ionomers aid in maintaining initial speed, contribute to
desired spin rate, and improve playability/impact durability as
well as acting as a moisture barrier to protect the cores from the
CoR loss. The cover, while originally intended to protect the golf
ball from scuffing, may also be modified to target a desired spin
rate, feel, and playability, even addressing such issues as "lift"
and "drag".
[0006] Golf ball manufacturers, motivated recently by concerns
about the welfare of the environment, have sought to incorporate
materials in the core, intermediate layer and/or cover which not
only improve performance, but are also at least in part
biodegradable, decomposable, and easily disposed of or discarded in
an environmentally friendly fashion. Conventionally, golf ball
cores and/or centers are constructed with a polybutadiene-based
polymer composition which is obtained from a non-renewable resource
such as petroleum, a non biodegradable/non renewable resource which
may cause some long term detrimental effects on the environment.
The core compositions of this type are constantly being altered in
an effort to provide a targeted or desired coefficient of
restitution ("COR") while at the same time resulting in a lower
compression which, in turn, can lower the golf ball spin rate,
provide better "feel," or both. This is a difficult task, however,
given the physical limitations of currently-available polymers.
Accordingly, there is a need for a material that overcomes these
limitations, meanwhile being biodegradable.
[0007] Manufacturers likewise struggle in their attempt to improve
intermediate and cover layers. For example, the hardness range in
golf ball utilizing conventional ionomer blends is still limited
and even the softest blends suffer from a "plastic" feel according
to some golfers. Recently, polyurethane-based materials have been
employed in golf ball layers and, in particular, outer cover
layers, due to their softer "feel" characteristics without loss in
resiliency and/or durability. However, these polyurethane
components are likewise petroleum based, furthering the long term
detrimental effect on the environment. Therefore, there remains a
similar need for novel and improved golf ball intermediate layer
and cover compositions having at least some biodegradable
characteristics.
[0008] One attempt to incorporate biodegradable materials in golf
balls is seen in U.S. 2006/0205534A1 of Egashira et al., which
discloses golf balls including ester group-containing or ester
group-free biodegradable compounds. However, Egashira et al., like
other attempts, fails to recognize or appreciate that the molecular
weight of the renewable resource component in a biodegradable
composition, i.e. low, medium high or ultra high is an important
consideration and directly impacts golf ball characteristics,
playability and melt processability during injection or compression
molding of golf ball layers. In this regard, Egashira et al.
explicitly instructs that no particular molecular weight limitation
should be placed on the biodegradable compounds. See Egashira et
al., for example, at [0018].
[0009] Meanwhile, Egashira et al. and other attempts to incorporate
biodegradable materials in golf balls do not disclose nor
appreciate the benefits of incorporating ultra high molecular
weight polyhydroxyalkanoate compounds (UHMWPHA) in at least one of
the core, core layer(s), intermediate layer(s) and cover layer(s)
of a golf ball to improve golf ball characteristics. Further,
heretofore, the benefits of including functional moieties such as
acid, ionic, ester, anhydride or amine in ultra high molecular
weight PHA golf ball compositions have also been overlooked.
[0010] Polyhydroxyalkanoates, or PHAs, are produced in nature by
bacterial fermentation of sugar or lipids. They are produced by the
bacteria to store carbon and energy. The resulting characteristics
of a PHA composition can be changed by altering any or all of the
bacterial strain being used, the carbon source, and the
fermentation conditions. Accordingly, due to this as well as the
chemical reactivity nature of PHA's, several different monomers can
be combined within this family to provide materials with a wide
range of different properties from very stiff to very soft, each of
which may be incorporated to achieve a desired golf ball
characteristic. Golf ball properties can also be easily and
inexpensively changed by blending, modifying the surface or
combining PHAs with other polymers, enzymes and inorganic
materials, making it possible for a wider range of
applications.
[0011] Hence, a golf ball designer can simply and inexpensively
manufacture golf balls including such biodegradable materials using
conventional golf ball manufacturing processes and methods to
impact either a low spin from a driver to a high spin golf ball
close to the green for better controllability. This is especially
true, given that homo and copolymers of PHAs have a wide range of
melting points ranging from about 40.degree. C. to about
180.degree. C.
[0012] Accordingly, there remains a need for an improved golf ball
comprising a renewable polymer composition having a biodegradable
ultra high molecular weight polyhydroxyalkanoate component
possessing a targeted molecular weight, strategically chosen in
order to optimize golf ball characteristics and performance on the
green.
SUMMARY OF THE INVENTION
[0013] This invention is therefore directed to an improved golf
ball comprising a renewable polymer composition comprising ultra
high molecular weight polyhydroxyalkanoate compounds and their
functionalized derivatives and blends. In particular, the golf ball
of the invention comprises a core and a cover, wherein at least one
of the core and the cover comprises about 10 wt % or greater of a
renewable polymer composition comprising a UHMWPHA compound having
the formula:
--OCR.sub.1R.sub.2(CR.sub.3R.sub.4).sub.nCO--
wherein n is an integer, and wherein R.sub.1, R.sub.2, R.sub.3 and
R.sub.4 are selected from the group comprising saturated and
unsaturated hydrocarbon radicals, halo- and hydroxy-substituted
radicals, hydroxy radicals, halogen radicals; nitrogen-substituted
radicals, oxygen-substituted radicals, or hydrogen atoms. Such
compositions provide improved resiliency and impact durability
during play. The ball travels a longer distance from a driver
swing, meanwhile maintaining controllability closer to the
green.
[0014] In one embodiment, the at least one of the core and the
cover further comprises about 90 wt % or less of either a non
renewable polymer composition, a different renewable polymer
composition, or blend thereof.
[0015] In the golf ball of the invention, two particularly
synergistic structural arrangements are simultaneously in place
within the renewable polymer composition to achieve high
resiliency, sustained impact durability, and soft feel. First, the
long chain of the UHMWPHA compound, characteristic of its ultra
high molecular weight, beneficially serves to transfer load more
effectively to the polymer backbone by strengthening intermolecular
interactions, resulting in a tougher golf ball material with higher
impact strength, etc. This occurs from an increase in chain
interactions such as Van der Waals attractions and entanglements
that come with increased chain length and tend to fix the
individual chains more strongly in position and resist deformations
and matrix breakup, both at higher stresses and higher
temperatures.
[0016] Meanwhile, the above-enumerated desired golf ball
characteristics are further enhanced or achieved where the UHMWPHA
compound and the at least one non-renewable polymer composition are
associated, coupled and/or bonded via/by at least one of a
dipole-dipole interaction, ion-dipole interaction, ion-ion
interaction and hydrogen bonding with other golf ball materials. In
one embodiment, the UHMWPHA exhibits a bond energy in the range of
from about 150 to 250 KJ/mol when bonded with at least one
non-renewable polymer composition by dipole-dipole interactions. In
another embodiment, the UHMWPHA exhibits a bond energy in the range
of from about 450 to 550 KJ/mol when bonded with at least one
non-renewable polymer composition by hydrogen bonding. In another
embodiment, the UHMWPHA exhibits a bond energy in the range of from
about 600 to 950 KJ/mol when bonded with at least one non-renewable
polymer composition by ion-dipole or ion-ion interactions. The
above bond energy may determined using any technique known in the
art, including a calorimetry technique.
[0017] By non-limiting example, the UHMWPHA compounds are
particularly suitable in golf ball compositions because they are
capable of being dipole-dipole coupled, ion-dipole coupled, ion-ion
coupled and/or coupled via hydrogen bonding with nonrenewable
conventional golf ball compositions. For example, these include,
without limit, hard and soft ionomers, acid co-polymers and
ter-polymers, polyurethanes, polyester elastomers, polyamide
elastomers, polyamides, and polyesters, polyureas, ABS, SAN, PMMA,
thermoplastic vulcanized elastomers, maleic anhydride or glycidyl
acrylate or methacrylate grafted polymers, polyphenylene oxides,
polycarbonates, block copolymers, alternate copolymers, epoxy
resins etc. Alternatively, although the UHMWPHA is thermoplastic in
nature, a thermoset UHMWPHA composition may be formed by
crosslinking it into the composition as fill or by post
cross-linking using chemical or radiation cross-linking techniques.
In either case, a renewable composition material is produced that
has two-ply strength--that is, not only within the renewable
polymer composition itself but also as between biodegradable and
non renewable materials.
[0018] Accordingly, this dual structural synergistic arrangement of
the invention within the renewable polymer composition of the golf
ball itself and between it and the non-renewable material enables
golf ball manufacturers to inexpensively provide a biodegradable
golf ball having high resiliency, sustained impact durability, and
soft feel.
DETAILED DESCRIPTION OF THE INVENTION
[0019] The inventive golf ball including a renewable polymer
composition may comprise any type of ball construction known in the
art. Such golf ball designs include, for example, single-piece,
two-piece, three-piece, four-piece, and five-piece designs so long
as at least one layer comprises a renewable component composition
prepared in accordance with this invention. The core, intermediate,
and/or cover portions of the ball may be single or
multi-layered.
[0020] The golf balls of this invention preferably include at least
one intermediate layer. As used herein, the term, "intermediate
layer" means a layer of the ball disposed between the core and
cover. The intermediate layer may be considered an outer core layer
or inner cover layer or any other layer disposed between the inner
core and outer cover of the ball. The intermediate layer also may
be referred to as a casing or mantle layer. The intermediate layer
preferably has water vapor barrier properties to prevent moisture
from penetrating into the rubber core. The ball may include one or
more intermediate layers disposed between the inner core and outer
cover.
[0021] The renewable resource component of the golf ball of the
invention may be disposed within any or all of the core, core
layer(s), intermediate layer(s) and cover layer(s) and associated,
coupled and/or bonded with at least one non-renewable polymer
composition by one of the following mechanisms: dipole-dipole
interaction, ion-dipole interaction, and hydrogen bonding. The
UHMWPHA may further comprise at least one ultra high molecular
weight polyhydroxyalkanoate compound selected, by non-limiting
example, from the group comprising homopolymers of
polyhydroxyalkanoate and polyhydroxybutyrate; a copolymer of
hydroxybutyric acid and hydroxyvaleric acid; a copolymer of
3-hydroxybutyric acid and 4-hydroxybutyric acid;
polyhydroxyoctanoate; a copolymer of 4-hydroxybutyric and
4-hydroxyhexanoic acid; a copolymer of 4-hydroxybutyric acid and
4-hydroxyoctanoic acid; a copolymer of 3-hydroxyoctanoic acid with
3-hydroxybutryic acid; a copolymer of 3-hydroxyhexanoic acid and
3-hydroxybutyric acid; a copolymer containing hydroxyoctonate
groups randomly distributed through the polymer chain and
combinations thereof.
[0022] In one embodiment, the ultra high molecular weight
polyhydroxyalkanoate compound comprises a molecular weight of about
60,000 grams/mole or greater. In another embodiment, the ultra high
molecular weight polyhydroxyalkanoate compound comprises a
molecular weight of from about 60,000 grams/mole to about 4,000,000
grams/mole. In yet another embodiment, the ultra high molecular
weight polyhydroxyalkanoate compound comprises a molecular weight
of from about 100,000 to 2,000,000. In still another embodiment,
the ultra high molecular weight polyhydroxyalkanoate compound may
comprise a molecular weight of from about 250,000 to about
1,000,000 grams/mole.
[0023] The at least one of the core and the cover of the invention
may comprise a hardness of from about 50 Shore C to about 90 Shore
C.
[0024] The golf ball may also comprise an intermediate layer
disposed about the core and adjacent the cover, wherein at least
one of the core, the cover and the intermediate layer comprises the
renewable polymer composition. In this embodiment, the at least one
of the core, the intermediate layer and the cover may comprise a
hardness of from about 50 Shore C to about 90 Shore C.
[0025] In one embodiment, the at least one of the core and the
cover comprises about 5 wt % or greater of the renewable polymer
composition. In another embodiment, the renewable polymer
composition comprises about 5 wt % or greater of the ultra high
molecular weight polyhydroxyalkanoate compound. In yet another
embodiment, the at least one of the core and the cover comprises
about 5 wt % or greater of the ultra high molecular weight
polyhydroxyalkanoate compound.
[0026] Furthermore, the mechanics and biocompatibility of UHMWPHA
can also be changed by blending, modifying the surface or combining
it with other polymers, enzymes and inorganic materials, making it
possible for a wider range of golfers to meet their golf ball
performance criteria, i.e. higher spin or lower spin on the golf
course.
[0027] The ultra high molecular weight polyhydroxyalkanoate
compound may further comprise end chain functionalities selected
from the group comprising vinyl, carboxylic acid, carboxylic acid
ester, anhydride, maleate, malic acid, fumaric acid, acetate,
hydroxy, amine, butyrate, propanoate, primary alcohol, secondary
alcohol, tertiary alcohol, amide, and polyhydric alcohol to provide
improved chemical compatibility with non-PHA renewable and
non-renewable polymers as well as to provide a desired golf ball
performance.
[0028] The ultra high molecular weight polyhydroxyalkanoate
compound may be formed from at least one of monomeric units and
oligomeric units selected from the group comprising
hydroxybutyrate, hydroxyvalerate, hydroxyhexanoate,
hydroxyheptanoate, hydroxyoctanoate, hydroxynonanoate,
hydroxydecanoate, hydroxyundecanoate, and hydroxydodecanoate and
blends thereof. In addition, the copolymers of PHA of the present
invention includes both random, alternate and block polymers.
[0029] In one embodiment, R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are
substantially similar. In another embodiment, R.sub.1, R.sub.2,
R.sub.3 and R.sub.4 are different. In yet another embodiment,
R.sub.1 is the same as at least one of R.sub.2, R.sub.3 and
R.sub.4. In still another embodiment, R.sub.2 is the same as at
least one of R.sub.1, R.sub.3 and R.sub.4. In still another
embodiment, R.sub.3 may be the same as at least one of R.sub.1,
R.sub.2, and R.sub.4. Meanwhile, R.sub.4 may be the same as at
least one of R.sub.1, R.sub.2, and R.sub.3.
[0030] In one embodiment, where n may be 500 or greater (n>500),
golf ball layer compositions comprising PHAs have good mechanical
properties such as a tensile strength at break, an elongation at
break and impact strength so that the golf balls exhibit good
impact durability during its usage. Furthermore, when n is greater
than 500, higher flexural modulus results and the golf ball will
thereby exhibit a reduced back spin from a driver thereby enhancing
its distance. This may be measured according to ASTM D790-03,
procedure B, for example.
[0031] Where at least the core comprises the renewable polymer
composition with improved resiliency and impact durability, the
core may alternatively comprise a surface hardness of from about 50
Shore C to about 90 Shore C, or from about 55 Shore C to about 85
Shore C, or even from about 60 Shore C to about 80 Shore C. Where
at least the cover comprises the renewable polymer composition, the
cover may alternatively comprise a surface hardness of from about
60 Shore C to about 90 Shore C, or even from about 65 Shore C to
about 85 Shore C. Where at least an intermediate layer comprises
the renewable polymer composition, the intermediate layer may
alternatively comprise a surface hardness of from 30 about Shore D
to about 75 Shore D, or from about 35 Shore D to about 70 Shore D,
or even from about 40 Shore D to about 68 Shore D such that a golf
ball has a low back spin-rate from a driver but still maintains its
controllability for a short game. In another embodiment, the core
comprises a first hardness of from about 50 Shore C to about 90
Shore C and the cover comprises a second hardness of from about 60
Shore C to about 95 Shore C wherein the ratio of the second
hardness to the first hardness is about 0.6 or greater, regardless
as to which of the core or the cover comprise the renewable polymer
composition so that a golf ball provides a increased distance and
control.
[0032] In another embodiment, where at least the core comprises the
renewable polymer composition, the core may comprise a hardness of
from about 30 Shore D to about 60 Shore D. Where at least the cover
comprises the renewable polymer composition, the cover may comprise
a hardness of from about 40 Shore D to about 65 Shore D. In an
embodiment which includes an intermediate layer, where at least the
intermediate layer comprises the renewable polymer composition, the
intermediate layer may comprise a hardness of from about 30 Shore D
to about 75 Shore D. In another embodiment, the core comprises a
first hardness of from about 10 Shore D to about 50 Shore D and the
cover comprises a second hardness of from about 30 Shore D to about
70 Shore D wherein the ratio of the second hardness to the first
hardness is about 3 or greater, regardless as to which of the core
or the cover comprise the renewable polymer composition.
[0033] The ultra high molecular weight polyhydroxyalkanoate
compound may comprise an acid or ester group content of from about
2.5% by wt to 25% by wt.
[0034] The ultra high molecular weight polyhydroxyalkanoate
compound may also comprise acid or ester groups wherein about 20 wt
% or greater of the acid groups are neutralized by a cation source
or about 20 wt % or greater of the ester groups are saponified by
an inorganic base so that improved scuff resistant and some
resiliency can be achieved in the ball. Alternatively, the ultra
high molecular weight polyhydroxyalkanoate compound may comprise
acid or ester groups wherein about 70 wt % or greater of the acid
groups are neutralized or about 70 wt % or greater of the ester
groups are saponified to provide additional boost in resiliency as
well as soft and fast characteristics. In another embodiment, the
ultra high molecular weight polyhydroxyalkanoate compound may
comprise acid or ester groups wherein from about 80 wt % to about
100 wt % of the acid groups are neutralized or from about 80 wt %
to about 100 wt % of the ester groups are saponified to improve
resiliency and soft and fast characteristics.
[0035] The ultra high molecular weight polyhydroxyalkanoate
compound may comprise a melt flow modifier selected from the group
comprising animal fats, plants, non-petroleum and petroleum based
organic acids and their salts. The ultra high molecular weight
polyhydroxyalkanoate compound may comprise the melt flow modifier
in an amount of about 10% by weight or greater so that the
compositions can provide improved processability such as enhanced
melt flow to fill the golf ball layers uniformly without shifting
the cores or intermediate layers. Alternatively, the ultra high
molecular weight polyhydroxyalkanoate compound may comprise the
melt flow modifier in an amount of from about 10% by weight to
about 50% by weight. Such compositions also provide improved
bio-degradability.
[0036] The renewable polymer composition may include a cation
selected from the group comprising Li, Na, K, Cs, Mg, Ca, Ba, Mn,
Zn, Cs, Zr, Ti, W, and Al such that those compositions provide
increased resiliency and scuff resistant due to a strong ionic
interaction between the ionic moieties. Preferably, Li, Na, Mg and
Zn cations are used in the present invention to provide a balance
golf ball performance such as a scuff resistant, resiliency and
control due to a cation size and its ionic strength.
[0037] In one embodiment, about 10 wt % to about 20 wt % of the
renewable polymer composition is crosslinked to provide improved
scuff resistance for a short game when the balls were stuck using
sharp grooved wedges. The cross-linking can be achieved in one case
by reacting functionalized PHAs such as hydroxyl or acid terminated
PHAs with glycidyl acrylate or methacrylate or maleic anhydride
based homo and copolymers from a non-renewable source like a
copolymer of ethylene-glycidyl acrylate or maleic anhydride grafted
ethylene-butene or hexene copolymer.
[0038] The at least one of the core and the cover further may
comprise at least one softening comonomer selected from the group
comprising alkyl acrylate, methacrylate, glycidyl acrylate, and
glycidyl methacrylate for further controllability of the golf ball
on the green. The at least one of the core and the cover may
alternatively include a stiffening agent including a density
adjusting filler selected from the group comprising zinc oxide,
barium sulfate, tungsten, tungsten oxide, tungsten carbide, glass
spheres, carbon or glass reinforced polymers or composites, carbon
nanotubes, and blends thereof to reduce a back spin-rate from the
driver shot to achieve maximum golf ball distance.
[0039] In one embodiment, the renewable polymer composition further
comprises an ester compatibilizer selected from the group
comprising a glycidyl ester, a maleic ester and an oligomeric
ester. The oligomeric ester may include, for example,
poly(1,3-butylene glycol-co-1,2-propylene glycol adipic acid)
terminated with 2-ethylhexanol, poly(neopentyl
glycol-co-1,4-butylene glycol adipic acid) terminated with
2-ethylhexanol, poly(1,3-butylene glycol adipic acid) unterminated,
poly(1,3-butylene glycol adipic acid) unterminated,
poly(1,2-propylene glycol adipic acid-co-phthahic acid) terminated
with 2-ethylhexanol, poly(neopentyl glycol adipic acid) terminated
with 2-ethylhexanol, poly(1,2-propylene glycol adipic
acid-co-phthalic acid) terminated with 2-ethylhexanol,
poly(1,2-propylene glycol-co-1,4-butylene glycol adipic acid)
terminated with 2 ethylhexanol, poly(1,3-butylene glycol adipic
acid) terminated with mixed fatty acids, poly(1,2-propylene glycol
adipic acid) terminated with 2-ethylhexanol, poly(1,2-propylene
glycol-co-1,4-butylene glycol adipic acid) terminated with
2-ethylhexanol, poly(1,4-butylene glycol adipic acid), or
poly(1,4-butylene glycol-co-ethylene glycol adipic acid).
[0040] The golf ball may comprise a blended composition comprising
the renewable polymer composition and at least one thermoplastic
material selected from the group comprising ethylene based
ionomers, highly neutralized polymers, polyester-ether elastomers,
polyester-ester elastomers, polyether-amide elastomers,
polyester-amide elastomers, polyurethane elastomers, thermoplastic
vulcanized materials, EPDM rubber, EPR rubber, SEBS rubber,
copolymers of ethylene-alkyl acrylates, copolymers of
methacrylates, glycidyl acrylate copolymers, methacrylate
copolymers, maleic anhydride grafted homopolymers, maleic anhydride
grafted copolymers and polycaprolactone. In one embodiment, the
blended composition comprises from about 50 wt % to about 95 wt %
of the at least one thermoplastic material.
[0041] The renewable polymer composition may further comprise at
least one renewable resource selected from the group comprising
lignin, crop oils, grains, plant derived glucose, yeast, fungi,
vegetable oils, canola oils, corn oils, flax, cellulose, fatty
acids, animal fats, tallow oils, fish oils, wood resins, tannis,
and polysaccharides to further enhance the bio-degradability and
some instances the processability of the UHMWPHA to fill a thin
layer of the golf ball to minimize the CoR loss and cost. In
another embodiment, the different renewable polymer composition
comprises at least one of these renewable resources.
[0042] In one embodiment, the renewable polymer composition further
comprises at least one renewable resource selected from the group
comprising soy protein, starch, polyesters, polylactic acids,
triglycerides, homo- and copolymers of polyhydroxyalkanoates. In
another embodiment, the different renewable polymer composition
comprises at least one of these renewable resources in order to
provide improved bio-degradability and melt processability along
with desired ball performance.
[0043] The golf ball of the present invention may also comprise non
renewable polymeric compositions including, for example, a
synthetic polymer selected from homo- and copolymers of polyolefin,
polyester, polycarbonate, polyamide, polyurethane, polyacrylic,
polyimide, epoxy and combinations thereof.
[0044] The cores in the golf balls of this invention may be solid,
semi-solid, hollow, fluid-filled, or powder-filled. Typically, the
cores are solid and made from rubber compositions containing a base
rubber, free-radical initiator agent, cross-linking co-agent,
fillers and 5 to 25 wt % of a renewable component of the present
invention. The addition of a renewable component provides some
biodegradable characteristics along with increased toughness and
improved golf ball performance like distance and control. The base
rubber may be selected, for example, from polybutadiene rubber,
polyisoprene rubber, natural rubber, ethylene-propylene rubber,
ethylene-propylene diene rubber, styrene-butadiene rubber, and
combinations of two or more thereof. A preferred base rubber is
polybutadiene.
[0045] Examples of desirable polybutadiene rubbers include
BUNA.RTM. CB22 and BUNA.RTM. CB23, TAKTENE.RTM. 1203G1, 220, 221,
and PETROFLEX.RTM. BRNd-40, commercially available from LANXESS
Corporation; BR-1220 available from BST Elastomers Co. LTD;
UBEPOL.RTM. 360L and UBEPOL.RTM. 150L and UBEPOL-BR rubbers,
commercially available from UBE Industries, Ltd. of Tokyo, Japan;
KINEX.RTM. 7245 and KINEX.RTM. 7265, commercially available from
Goodyear of Akron, Ohio; SE BR-1220, commercially available from
Dow Chemical Company; Europrene.RTM. NEOCIS.RTM. BR 40 and BR 60,
commercially available from Polimeri Europa; and BR 01, BR 730, BR
735, BR 11, and BR 51, commercially available from Japan Synthetic
Rubber Co., Ltd; and KARBOCHEM.RTM. ND40, ND45, and ND60,
commercially available from Karbochem.
[0046] Another preferred base rubber is polybutadiene optionally
mixed with one or more elastomers such as polyisoprene rubber,
natural rubber, ethylene propylene rubber, ethylene propylene diene
rubber, styrene-butadiene rubber, polystyrene elastomers,
polyethylene elastomers, polyurethane elastomers, polyurea
elastomers, acrylate rubbers, polyoctenamers, metallocene-catalyzed
elastomers, and plastomers. As discussed further below, highly
neutralized acid copolymers (HNPs), as known in the art, also can
be used to form the core layer which is blended with 5 to 25 wt %
of a renewable component of the present invention. Such
compositions will provide increased flexural modulus and toughness
thereby improving the golf ball's performance including its impact
durability along with some biodegradable characteristics for the
environment.
[0047] The base rubber typically is mixed with at least one
reactive cross-linking co-agent to enhance the hardness of the
rubber composition. Suitable co-agents include, but are not limited
to, unsaturated carboxylic acids and unsaturated vinyl compounds. A
preferred unsaturated vinyl is trimethylolpropane trimethacrylate.
The rubber composition is cured using a conventional curing
process. Suitable curing processes include, for example, peroxide
curing, sulfur curing, high-energy radiation, and combinations
thereof. In one embodiment, the base rubber is peroxide cured.
Organic peroxides suitable as free-radical initiators include, for
example, dicumyl peroxide; n-butyl-4,4-di(t-butylperoxy)valerate;
1,1-di(t-butylperoxy)3,3,5-trimethylcyclohexane;
2,5-dimethyl-2,5-di(t-butylperoxy)hexane; di-t-butyl peroxide;
di-t-amyl peroxide; t-butyl peroxide; t-butyl cumyl peroxide;
2,5-dimethyl-2,5-di(t-butylperoxy)hexyne-3;
di(2-t-butyl-peroxyisopropyl)benzene; dilauroyl peroxide; dibenzoyl
peroxide; t-butyl hydroperoxide; and combinations thereof.
Cross-linking agents are used to cross-link at least a portion of
the polymer chains in the composition. Suitable cross-linking
agents include, for example, metal salts of unsaturated carboxylic
acids having from 3 to 8 carbon atoms; unsaturated vinyl compounds
and polyfunctional monomers (for example, trimethylolpropane
trimethacrylate); phenylene bismaleimide; and combinations thereof.
In a particular embodiment, the cross-linking agent is selected
from zinc salts of acrylates, diacrylates, methacrylates, and
dimethacrylates. In another particular embodiment, the
cross-linking agent is zinc diacrylate ("ZDA"). Commercially
available zinc diacrylates include those selected from Rockland
React-Rite and Sartomer.
[0048] The base rubber may also comprise high or medium Mooney
viscosity rubber, or blends thereof. The measurement of Mooney
viscosity is defined according to ASTM D-1646. The Mooney viscosity
range is preferably greater than about 30, more preferably in the
range from about 35 to about 75 and more preferably in the range
from about 40 to about 60. Polybutadiene rubber with higher Mooney
viscosity may also be used, so long as the viscosity of the
polybutadiene does not reach a level where the high viscosity
polybutadiene clogs or otherwise adversely interferes with the
manufacturing machinery. It is contemplated that polybutadiene with
viscosity less than about 75 Mooney can be used with the present
invention.
[0049] In one embodiment of the present invention, golf ball cores
made with mid- to high-Mooney viscosity polybutadiene material
exhibit increased resiliency (and, therefore, distance) without
increasing the hardness of the ball.
[0050] Commercial sources of suitable mid- to high-Mooney viscosity
polybutadiene include Lanxess Buna CB23 (Nd-catalyzed), which has a
Mooney viscosity of around 50 and is a highly linear polybutadiene,
and Dow SE BR-1220 (Co-catalyzed). If desired, the polybutadiene
can also be mixed with other elastomers known in the art, such as
other polybutadiene rubbers, natural rubber, styrene butadiene
rubber, and/or isoprene rubber in order to further modify the
properties of the core. When a mixture of elastomers is used, the
amounts of other constituents in the core composition are typically
based on 100 parts by weight of the total elastomer mixture.
[0051] Thermoplastic elastomers (TPE) many also be used to modify
the properties of the core layers, or the uncured core layer stock
by blending with the base thermoset rubber. These TPEs include
natural or synthetic balata, or high trans-polyisoprene, high
trans-polybutadiene, or any styrenic block copolymer, such as
styrene ethylene butadiene styrene, styrene-isoprene-styrene, etc.,
a metallocene or other single-site catalyzed polyolefin such as
ethylene-octene, or ethylene-butene, or thermoplastic polyurethanes
(TPU), including copolymers, e.g. with silicone. Other suitable
TPEs for blending with the thermoset rubbers of the present
invention include PEBAX.RTM., which is believed to comprise
polyether amide copolymers, HYTREL.RTM., which is believed to
comprise polyether ester copolymers, thermoplastic urethane, and
KRATON.RTM., which is believed to comprise styrenic block
copolymers elastomers. Any of the TPEs or TPUs above may also
contain functionality suitable for grafting, including maleic acid
or maleic anhydride. Any of the Thermoplastic Vulcanized Rubbers
(TPV) such as Santoprene.RTM. or Vibram.RTM. or ETPV.RTM. can be
used along with a present invention. In one embodiment, the TPV has
a thermoplastic as a continuous phase and a cross-linked rubber
particulate as a dispersed (or discontinuous) phase. In another
embodiment, the TPV has a cross-linked phase as a continuous phase
and a thermoplastic as a dispersed (or discontinuous) phase to
provide reduced loss in elasticity in order to improve the
resiliency of the golf ball.
[0052] The rubber compositions also may contain "soft and fast"
agents such as a halogenated organosulfur, organic disulfide, or
inorganic disulfide compounds. Particularly suitable halogenated
organosulfur compounds include, but are not limited to, halogenated
thiophenols. Preferred organic sulfur compounds include, but not
limited to, pentachlorothiophenol ("PCTP") and a salt of PCTP. A
preferred salt of PCTP is ZnPCTP. A suitable PCTP is sold by the
Struktol Company (Stow, Ohio) under the tradename, A95. ZnPCTP is
commercially available from EchinaChem (San Francisco, Calif.).
These compounds also may function as cis-to-trans catalysts to
convert some cis-1, 4 bonds in the polybutadiene to trans-1, 4
bonds. Antioxidants also may be added to the rubber compositions to
prevent the breakdown of the elastomers. Other ingredients such as
accelerators (for example, tetra methylthiuram), processing aids,
dyes and pigments, wetting agents, surfactants, plasticizers, as
well as other additives known in the art may be added to the rubber
composition.
[0053] The core may be formed by mixing and forming the rubber
composition using conventional techniques. These cores can be used
to make finished golf balls by surrounding the core with outer core
layer(s), intermediate layer(s), and/or cover materials as
discussed further below. In another embodiment, the cores can be
formed using highly neutralized polymer (HNP) compositions as
disclosed in U.S. Pat. Nos. 6,756,436, 7,030,192, 7,402,629, and
7,517,289. The cores from the highly neutralized polymer
compositions can be further cross-linked using any free-radical
initiation sources including radiation sources such as gamma or
electron beam as well as chemical sources such as peroxides and the
like.
[0054] The core may contain sections having the same hardness or
different hardness levels. That is, there can be uniform hardness
throughout the different sections of the core or there can be
hardness gradients across the layers. For example, in single cores,
there may be a hard-to-soft gradient (a "positive" gradient) from
the surface of the core to the geometric center of the core. In
other instances, the there may be a soft-to-hard gradient (a
"negative" gradient) or zero hardness gradient from the core's
surface to the core's center. For dual core golf balls, the inner
core layer may have a surface hardness that is less than the
geometric center hardness to define a first "negative" gradient. As
discussed above, an outer core layer may be formed around the inner
core layer, and the outer core layer may have an outer surface
hardness less than its inner surface hardness to define a second
"negative" gradient. In other versions, the hardness gradients from
surface to center may be hard-to-soft ("positive"), or soft-to-hard
("negative"), or a combination of both gradients. In still other
versions the hardness gradients from surface to center may be
"zero" (that is, the hardness values are substantially the same.)
Methods for making cores having positive, negative, and zero
hardness gradients are known in the art as described in, for
example, U.S. Pat. Nos. 7,537,530; 7,537,529; 7,427,242; and
7,410,429, the disclosures of which are hereby incorporated by
reference.
[0055] Golf balls made in accordance with this invention can be of
any size, although the USGA requires that golf balls used in
competition have a diameter of at least 1.68 inches and a weight of
no greater than 1.62 ounces. For play outside of USGA competition,
the golf balls can have smaller diameters and be heavier.
[0056] The renewable component composition of this invention can be
used to make the outer core, intermediate layer, inner cover,
and/or outer cover. In some instances, a traditional thermoplastic
or thermosetting composition may be used to make one layer and the
renewable component composition may be used to make a different
layer of the golf ball depending upon the desired ball construction
playing performance properties. If a conventional thermoplastic or
thermosetting composition is used in one layer (and the renewable
component composition used in a different layer), then a wide
variety of thermoplastic or thermosetting materials can be
employed. These materials include for example, olefin-based
copolymer ionomer resins (for example, Surlyn.RTM. ionomer resins
and DuPont.RTM. HPF 1000 and HPF 2000, commercially available from
E. I. du Pont de Nemours and Company; Iotek.RTM. ionomers,
commercially available from ExxonMobil Chemical Company;
Amplify.RTM. JO ionomers of ethylene acrylic acid copolymers,
commercially available from The Dow Chemical Company; and
Clarix.RTM. ionomer resins, commercially available from A. Schulman
Inc.); polyurethanes; polyureas; copolymers and hybrids of
polyurethane and polyurea; polyethylene, including, for example,
low density polyethylene, linear low density polyethylene, and high
density polyethylene; polypropylene; rubber-toughened olefin
polymers; acid copolymers, for example, poly(meth)acrylic acid,
which do not become part of an ionomeric copolymer; plastomers;
flexomers; styrene/butadiene/styrene block copolymers;
styrene/ethylene-butylene/styrene block copolymers; dynamically
vulcanized elastomers; copolymers of ethylene and vinyl acetates;
copolymers of ethylene and methyl acrylates; polyvinyl chloride
resins; polyamides, poly(amide-ester) elastomers, and graft
copolymers of ionomer and polyamide including, for example,
Pebax.RTM. thermoplastic polyether block amides, commercially
available from Arkema Inc; cross-linked trans-polyisoprene and
blends thereof; polyester-based thermoplastic elastomers, such as
Hytrel.RTM., commercially available from E. I. du Pont de Nemours
and Company; polyurethane-based thermoplastic elastomers, such as
Elastollan.RTM., commercially available from BASF; synthetic or
natural vulcanized rubber; and combinations thereof.
[0057] While the inventive golf ball may be formed from a variety
of differing and conventional materials for the intermediate
layer(s), inner cover layer(s) and/or outer cover layer(s),
preferred cover materials include, but are not limited to:
[0058] (1) Polyurethanes, such as those prepared from polyols or
polyamines and diisocyanates or polyisocyanates and/or their
prepolymers, and those disclosed in U.S. Pat. Nos. 5,334,673 and
6,506,851;
[0059] (2) Polyureas, such as those disclosed in U.S. Pat. Nos.
5,484,870 and 6,835,794; and
[0060] (3) Polyurethane-urea hybrids, blends or copolymers
comprising urethane or urea segments.
[0061] Suitable polyurethane compositions comprise a reaction
product of at least one polyisocyanate and at least one curing
agent. The curing agent can include, for example, one or more
polyamines, one or more polyols, or a combination thereof. The
polyisocyanate can be combined with one or more polyols to form a
prepolymer, which is then combined with the at least one curing
agent. Thus, the polyols described herein are suitable for use in
one or both components of the polyurethane material, i.e., as part
of a prepolymer and in the curing agent. Suitable polyurethanes are
described in U.S. Patent Application Publication No. 2005/0176523,
which is incorporated by reference in its entirety.
[0062] Any polyisocyanate available to one of ordinary skill in the
art is suitable for use according to the invention. Exemplary
polyisocyanates include, but are not limited to,
4,4'-diphenylmethane diisocyanate (MDI); polymeric MDI;
carbodiimide-modified liquid MDI; 4,4'-dicyclohexylmethane
diisocyanate (H.sub.12MDI); p-phenylene diisocyanate (PPDI);
m-phenylene diisocyanate (MPDI); toluene diisocyanate (TDI);
3,3'-dimethyl-4,4'-biphenylene diisocyanate;
isophoronediisocyanate; 1,6-hexamethylene diisocyanate (HDI);
naphthalene diisocyanate; xylene diisocyanate; p-tetramethylxylene
diisocyanate; m-tetramethylxylene diisocyanate; ethylene
diisocyanate; propylene-1,2-diisocyanate;
tetramethylene-1,4-diisocyanate; cyclohexyl diisocyanate;
dodecane-1,12-diisocyanate; cyclobutane-1,3-diisocyanate;
cyclohexane-1,3-diisocyanate; cyclohexane-1,4-diisocyanate;
1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane; methyl
cyclohexylene diisocyanate; triisocyanate of HDI; triisocyanate of
2,4,4-trimethyl-1,6-hexane diisocyanate; tetracene diisocyanate;
napthalene diisocyanate; anthracene diisocyanate; isocyanurate of
toluene diisocyanate; uretdione of hexamethylene diisocyanate; and
mixtures thereof. Polyisocyanates are known to those of ordinary
skill in the art as having more than one isocyanate group, e.g.,
di-isocyanate, tri-isocyanate, and tetra-isocyanate. Preferably,
the polyisocyanate includes MDI, PPDI, TDI, or a mixture thereof,
and more preferably, the polyisocyanate includes MDI. It should be
understood that, as used herein, the term MDI includes
4,4'-diphenylmethane diisocyanate, polymeric MDI,
carbodiimide-modified liquid MDI, and mixtures thereof and,
additionally, that the diisocyanate employed may be "low free
monomer," understood by one of ordinary skill in the art to have
lower levels of "free" monomer isocyanate groups, typically less
than about 0.1% free monomer isocyanate groups. Examples of "low
free monomer" diisocyanates include, but are not limited to Low
Free Monomer MDI, Low Free Monomer TDI, and Low Free Monomer
PPDI.
[0063] Any polyol available to one of ordinary skill in the art is
suitable for use according to the invention. Exemplary polyols
include, but are not limited to, polyether polyols,
hydroxy-terminated polybutadiene (including partially/fully
hydrogenated derivatives), polyester polyols, polycaprolactone
polyols, and polycarbonate polyols. In one preferred embodiment,
the polyol includes polyether polyol. Examples include, but are not
limited to, polytetramethylene ether glycol (PTMEG), polyethylene
propylene glycol, polyoxypropylene glycol, and mixtures thereof.
The hydrocarbon chain can have saturated or unsaturated bonds and
substituted or unsubstituted aromatic and cyclic groups.
Preferably, the polyol of the present invention includes PTMEG.
[0064] In another embodiment, polyester polyols are included in the
polyurethane material. Suitable polyester polyols include, but are
not limited to, polyethylene adipate glycol; polybutylene adipate
glycol; polyethylene propylene adipate glycol;
o-phthalate-1,6-hexanediol; poly(hexamethylene adipate) glycol; and
mixtures thereof. The hydrocarbon chain can have saturated or
unsaturated bonds, or substituted or unsubstituted aromatic and
cyclic groups.
[0065] In another embodiment, polycaprolactone polyols are included
in the materials of the invention. Suitable polycaprolactone
polyols include, but are not limited to, 1,6-hexanediol-initiated
polycaprolactone, diethylene glycol initiated polycaprolactone,
trimethylol propane initiated polycaprolactone, neopentyl glycol
initiated polycaprolactone, 1,4-butanediol-initiated
polycaprolactone, and mixtures thereof. The hydrocarbon chain can
have saturated or unsaturated bonds, or substituted or
unsubstituted aromatic and cyclic groups.
[0066] In yet another embodiment, polycarbonate polyols are
included in the polyurethane material of the invention. Suitable
polycarbonates include, but are not limited to, polyphthalate
carbonate and poly(hexamethylene carbonate) glycol. The hydrocarbon
chain can have saturated or unsaturated bonds, or substituted or
unsubstituted aromatic and cyclic groups. In one embodiment, the
molecular weight of the polyol is from about 200 to about 4000.
[0067] Polyamine curatives are also suitable for use in the
polyurethane composition of the invention and have been found to
improve cut, shear, and impact resistance of the resultant balls.
Preferred polyamine curatives include, but are not limited to,
3,5-dimethylthio-2,4-toluenediamine and isomers thereof;
3,5-diethyltoluene-2,4-diamine and isomers thereof, such as
3,5-diethyltoluene-2,6-diamine;
4,4'-bis-(sec-butylamino)-diphenylmethane;
1,4-bis-(sec-butylamino)-benzene,
4,4'-methylene-bis-(2-chloroaniline);
4,4'-methylene-bis-(3-chloro-2,6-diethylaniline);
polytetramethyleneoxide-di-p-aminobenzoate; N,N'-dialkyldiamino
diphenyl methane; p,p'-methylene dianiline; m-phenylenediamine;
4,4'-methylene-bis-(2-chloroaniline);
4,4'-methylene-bis-(2,6-diethylaniline);
4,4'-methylene-bis-(2,3-dichloroaniline);
4,4'-diamino-3,3'-diethyl-5,5'-dimethyl diphenylmethane;
2,2',3,3'-tetrachloro diamino diphenylmethane; trimethylene glycol
di-p-aminobenzoate; and mixtures thereof.
[0068] Preferably, the curing agent of the present invention
includes 3,5-dimethylthio-2,4-toluenediamine and isomers thereof,
such as ETHACURE.RTM. 300, commercially available from Albermarle
Corporation of Baton Rouge, La. Suitable polyamine curatives, which
include both primary and secondary amines, preferably have
molecular weights ranging from about 64 to about 2000.
[0069] At least one of a diol, triol, tetraol, or
hydroxy-terminated curatives may be added to the aforementioned
polyurethane composition. Suitable diol, triol, and tetraol groups
elude ethylene glycol; diethylene glycol; polyethylene glycol;
propylene glycol; polypropylene glycol; lower molecular weight
polytetramethylene ether glycol; 1,3-bis(2-hydroxyethoxy)benzene;
1,3-bis-[2-(2-hydroxyethoxy)ethoxy]benzene;
1,3-bis-{2-[2-(2-hydroxyethoxy)ethoxy]ethoxy}benzene;
1,4-butanediol; 1,5-pentanediol; 1,6-hexanediol;
resorcinol-di-(.beta.-hydroxyethyl)ether;
hydroquinone-di-(.beta.-hydroxyethyl)ether; and mixtures thereof.
Preferred hydroxy-terminated curatives include
1,3-bis(2-hydroxyethoxy)benzene;
1,3-bis-[2-(2-hydroxyethoxy)ethoxy]benzene;
1,3-bis-{2-[2-(2-hydroxyethoxy)ethoxy]ethoxy}benzene;
1,4-butanediol, and mixtures thereof. Preferably, the
hydroxy-terminated curatives have molecular weights ranging from
about 48 to 2000. It should be understood that molecular weight, as
used herein, is the absolute weight average molecular weight and
would be understood as such by one of ordinary skill in the
art.
[0070] Both the hydroxy-terminated and amine curatives can include
one or more saturated, unsaturated, aromatic, and cyclic groups.
Additionally, the hydroxy-terminated and amine curatives can
include one or more halogen groups. The polyurethane composition
can be formed with a blend or mixture of curing agents. If desired,
however, the polyurethane composition may be formed with a single
curing agent.
[0071] In a preferred embodiment of the present invention,
saturated polyurethanes are used to form one or more of the cover
layers, preferably the outer cover layer, and may be selected from
among both castable thermoset and thermoplastic polyurethanes.
[0072] Thermosetting polyurethanes or polyureas are suitable for
the outer cover layers of the golf balls of the invention.
[0073] Additionally, polyurethane can be replaced with or blended
with a polyurea material. Polyureas are distinctly different from
polyurethane compositions, but also result in desirable aerodynamic
and aesthetic characteristics when used in golf ball components.
The polyurea-based compositions are preferably saturated in
nature.
[0074] The polyether amine may be blended with additional polyols
to formulate copolymers that are reacted with excess isocyanate to
form the polyurea prepolymer. In one embodiment, less than about 30
percent polyol by weight of the copolymer is blended with the
saturated polyether amine. In another embodiment, less than about
20 percent polyol by weight of the copolymer, preferably less than
about 15 percent by weight of the copolymer, is blended with the
polyether amine. The polyols listed above with respect to the
polyurethane prepolymer, e.g., polyether polyols, polycaprolactone
polyols, polyester polyols, polycarbonate polyols, hydrocarbon
polyols, other polyols, and mixtures thereof, are also suitable for
blending with the polyether amine. The molecular weight of these
polymers may be from about 200 to about 4000, but also may be from
about 1000 to about 3000, and more preferably are from about 1500
to about 2500.
[0075] The polyurea composition can be formed by crosslinking a
polyurea prepolymer with a single curing agent or a blend of curing
agents. The curing agent of the invention is preferably an
amine-terminated curing agent, more preferably a secondary diamine
curing agent so that the composition contains only urea linkages.
In one embodiment, the amine-terminated curing agent may have a
molecular weight of about 64 or greater. In another embodiment, the
molecular weight of the amine-curing agent is about 2000 or less.
As discussed above, certain amine-terminated curing agents may be
modified with a compatible amine-terminated freezing point
depressing agent or mixture of compatible freezing point depressing
agents
[0076] Suitable amine-terminated curing agents include, but are not
limited to, ethylene diamine; hexamethylene diamine;
1-methyl-2,6-cyclohexyl diamine; tetrahydroxypropylene ethylene
diamine; 2,2,4- and 2,4,4-trimethyl-1,6-hexanediamine;
4,4'-bis-(sec-butylamino)-dicyclohexylmethane;
1,4-bis-(sec-butylamino)-cyclohexane;
1,2-bis-(sec-butylamino)-cyclohexane; derivatives of
4,4'-bis-(sec-butylamino)-dicyclohexylmethane;
4,4'-dicyclohexylmethane diamine;
1,4-cyclohexane-bis-(methylamine);
1,3-cyclohexane-bis-(methylamine); diethylene glycol
di-(aminopropyl)ether; 2-methylpentamethylene-diamine;
diaminocyclohexane; diethylene triamine; tri ethylene tetramine;
tetraethylene pentamine; propylene diamine; 1,3-diaminopropane;
dimethyl amino propylamine; diethylamino propylamine; dipropylene
triamine; imido-bis-propylamine; monoethanolamine, diethanolamine;
triethanolamine; monoisopropanolamine, diisopropanolamine;
isophoronediamine; 4,4'-methylenebis-(2-chloroaniline); 3,5;
dimethylthio-2,4-toluenediamine;
3,5-dimethylthio-2,6-toluenediamine;
3,5-diethylthio-2,4-toluenediamine; 3,5;
diethylthio-2,6-toluenediamine;
4,4'-bis-(sec-butylamino)-diphenylmethane and derivatives thereof;
1,4-bis-(sec-butylamino)-benzene; 1,2-bis-(sec-butylamino)-benzene;
N,N'-dialkylamino-diphenylmethane;
N,N,N',N'-tetrakis(2-hydroxypropyl)ethylene diamine;
trimethyleneglycol-di-p-aminobenzoate;
polytetramethyleneoxide-di-p-aminobenzoate;
4,4'-methylenebis-(3-chloro-2,6-diethyleneaniline);
4,4'-methylenebis-(2,6-diethylaniline); meta-phenylenediamine;
paraphenylenediamine; and mixtures thereof. In one embodiment, the
amine-terminated curing agent is
4,4'-bis-(sec-butylamino)-dicyclohexylmethane.
[0077] Suitable saturated amine-terminated curing agents include,
but are not limited to, ethylene diamine; hexamethylene diamine;
1-methyl-2,6-cyclohexyl diamine; tetrahydroxypropylene ethylene
diamine; 2,2,4- and 2,4,4-trimethyl-1,6-hexanediamine;
4,4'-bis-(sec-butylamino)-dicyclohexylmethane;
1,4-bis-(sec-butylamino)-cyclohexane;
1,2-bis-(sec-butylamino)-cyclohexane; derivatives of
4,4'-bis-(sec-butylamino)-dicyclohexylmethane;
4,4'-dicyclohexylmethane diamine;
4,4'-methylenebis-(2,6-diethylaminocyclohexane;
1,4-cyclohexane-bis-(methylamine);
1,3-cyclohexane-bis-(methylamine); diethylene glycol
di-(aminopropyl)ether; 2-methylpentamethylene-diamine;
diaminocyclohexane; diethylene triamine; triethylene tetramine;
tetraethylene pentamine; propylene diamine; 1,3-diaminopropane;
dimethylamino propylamine; diethylamino propylamine;
imido-bis-propylamine; monoethanolamine, diethanolamine;
triethanolamine; monoisopropanolamine, diisopropanolamine;
isophoronediamine; triisopropanolamine; and mixtures thereof. In
addition, any of the polyether amines listed above may be used as
curing agents to react with the polyurea prepolymers.
[0078] Alternatively, other suitable polymers include partially or
fully neutralized ionomer, metallocene, or other single-site
catalyzed polymer, polyester, polyamide, non-ionomeric
thermoplastic elastomer, copolyether-esters, copolyether-amides,
polycarbonate, polybutadiene, polyisoprene, polystryrene block
copolymers (such as styrene-butadiene-styrene),
styrene-ethylene-propylene-styrene,
styrene-ethylene-butylene-styrene, and the like, and blends
thereof.
[0079] Cover layers of the inventive golf ball may also be formed
from ionomeric polymers, preferably highly-neutralized ionomers
(HNP). In a preferred embodiment, at least one intermediate layer
of the golf ball is formed from an HNP material or a blend of HNP
materials. The acid moieties of the HNP's, typically ethylene-based
ionomers, are preferably neutralized greater than about 70%, more
preferably greater than about 90%, and most preferably at least
about 100%. The HNP's can be also be blended with a second polymer
component, which, if containing an acid group, may be neutralized
in a conventional manner, by the organic fatty acids of the present
invention, or both. The second polymer component, which may be
partially or fully neutralized, preferably comprises ionomeric
copolymers and terpolymers, ionomer precursors, thermoplastics,
polyamides, polycarbonates, polyesters, polyurethanes, polyureas,
thermoplastic elastomers, polybutadiene rubber, balata,
metallocene-catalyzed polymers (grafted and non-grafted),
single-site polymers, high-crystalline acid polymers, cationic
ionomers, and the like. HNP polymers typically have a material
hardness of between about 20 and about 80 Shore D, and a flexural
modulus of between about 3,000 psi and about 200,000 psi.
[0080] In one embodiment of the present invention the HNP's are
ionomers and/or their acid precursors that are preferably
neutralized, either fully or partially, with organic acid
copolymers or the salts thereof. The acid copolymers are preferably
.alpha.-olefin, such as ethylene, C.sub.3-8
.alpha.,.beta.-ethylenically unsaturated carboxylic acid, such as
acrylic and methacrylic acid, copolymers. They may optionally
contain a softening monomer, such as alkyl acrylate and alkyl
methacrylate, wherein the alkyl groups have from 1 to 8 carbon
atoms.
[0081] The acid copolymers can be described as E/X/Y copolymers
where E is ethylene, X is an .alpha.,.beta.-ethylenically
unsaturated carboxylic acid, and Y is a softening comonomer. In a
preferred embodiment, X is acrylic or methacrylic acid and Y is a
C.sub.1-8 alkyl acrylate or methacrylate ester. X is preferably
present in an amount from about 1 to about 35 weight percent of the
polymer, more preferably from about 5 to about 30 weight percent of
the polymer, and most preferably from about 10 to about 20 weight
percent of the polymer. Y is preferably present in an amount from
about 0 to about 50 weight percent of the polymer, more preferably
from about 5 to about 25 weight percent of the polymer, and most
preferably from about 10 to about 20 weight percent of the
polymer.
[0082] Specific acid-containing ethylene copolymers include, but
are not limited to, ethylene/acrylic acid/n-butyl acrylate,
ethylene/methacrylic acid/n-butyl acrylate, ethylene/methacrylic
acid/iso-butyl acrylate, ethylene/acrylic acid/iso-butyl acrylate,
ethylene/methacrylic acid/n-butyl methacrylate, ethylene/acrylic
acid/methyl methacrylate, ethylene/acrylic acid/methyl acrylate,
ethylene/methacrylic acid/methyl acrylate, ethylene/methacrylic
acid/methyl methacrylate, and ethylene/acrylic acid/n-butyl
methacrylate. Preferred acid-containing ethylene copolymers
include, ethylene/methacrylic acid/n-butyl acrylate,
ethylene/acrylic acid/n-butyl acrylate, ethylene/methacrylic
acid/methyl acrylate, ethylene/acrylic acid/ethyl acrylate,
ethylene/methacrylic acid/ethyl acrylate, and ethylene/acrylic
acid/methyl acrylate copolymers. The most preferred acid-containing
ethylene copolymers are, ethylene/(meth) acrylic acid/n-butyl,
acrylate, ethylene/(meth)acrylic acid/ethyl acrylate, and
ethylene/(meth) acrylic acid/methyl acrylate copolymers.
[0083] Ionomers are typically neutralized with a metal cation, such
as Li, Na, Mg, K, Ca, or Zn. It has been found that by adding
sufficient organic acid or salt of organic acid, along with a
suitable base, to the acid copolymer or ionomer, however, the
ionomer can be neutralized, without losing processability, to a
level much greater than for a metal cation. Preferably, the acid
moieties are neutralized greater than about 80%, preferably from
90-100%, most preferably 100% without losing processability. This
accomplished by melt-blending an ethylene
.alpha.,.beta.-ethylenically unsaturated carboxylic acid copolymer,
for example, with an organic acid or a salt of organic acid, and
adding a sufficient amount of a cation source to increase the level
of neutralization of all the acid moieties (including those in the
acid copolymer and in the organic acid) to greater than 90%,
(preferably greater than 100%).
[0084] The organic acids of the present invention are aliphatic,
mono- or multi-functional (saturated, unsaturated, or
multi-unsaturated) organic acids. Salts of these organic acids may
also be employed. The salts of organic acids of the present
invention include the salts of barium, lithium, sodium, zinc,
bismuth, chromium, cobalt, copper, potassium, strontium, titanium,
tungsten, magnesium, cesium, iron, nickel, silver, aluminum, tin,
or calcium, salts of fatty acids, particularly stearic, behenic,
erucic, oleic, linoelic or dimerized derivatives thereof. It is
preferred that the organic acids and salts of the present invention
be relatively non-migratory (they do not bloom to the surface of
the polymer under ambient temperatures) and non-volatile (they do
not volatilize at temperatures required for melt-blending).
[0085] The ionomers of the invention may also be more conventional
ionomers, i.e., partially-neutralized with metal cations. The acid
moiety in the acid copolymer is neutralized about 1 to about 90%,
preferably at least about 20 to about 75%, and more preferably at
least about 40 to about 70%, to form an ionomer, by a cation such
as lithium, sodium, potassium, magnesium, calcium, barium, lead,
tin, zinc, aluminum, or a mixture thereof.
[0086] A moisture vapor barrier layer, such as disclosed in U.S.
Pat. Nos. 6,632,147; 6,932,720; 7,004,854; and 7,182,702, all of
which are incorporated by reference herein in their entirety, are
optionally employed between the cover layer and the core. The
moisture barrier layer may be disposed between the outer core layer
and the cover layer. The moisture vapor barrier protects the inner
and outer cores from degradation due to exposure to moisture, for
example water, and extends the usable life of the golf ball. In one
embodiment, the moisture barrier layer comprises a UHMWPHA as
defined and described herein. The moisture vapor transmission rate
of the moisture barrier layer is selected to be less than the
moisture vapor transmission rate of the cover layer. The moisture
barrier layer has a specific gravity of from about 1.1 to about 1.2
and a thickness of less than about 0.03 inches. Other suitable
materials for the moisture barrier layer include a combination of a
styrene block copolymer and a flaked metal, for example aluminum
flake.
[0087] The UHMWPHAs of the inventive composition may also be foamed
using any foaming technique known in the art to provide a softer
feel for playability.
[0088] The renewable component composition constituting the
layer(s) of the golf ball may contain additives, ingredients, and
other materials in amounts that do not detract from the properties
of the final composition. These additive materials include, but are
not limited to, activators such as calcium or magnesium oxide;
fatty acids such as stearic acid and salts thereof; fillers and
reinforcing agents such as organic or inorganic particles, for
example, clays, talc, calcium, magnesium carbonate, silica,
aluminum silicates zeolites, powdered metals, and organic or
inorganic fibers, plasticizers such as dialkyl esters of
dicarboxylic acids; surfactants; softeners; tackifiers; waxes;
ultraviolet (UV) light absorbers and stabilizers; antioxidants;
optical brighteners; whitening agents such as titanium dioxide and
zinc oxide; dyes and pigments; processing aids; release agents; and
wetting agents. These compositions provide improved melt
processability, a balance of ball performance.
[0089] The renewable component of this invention may be blended
with non-ionomeric and olefin-based ionomeric polymers to form the
composition that will be used to make the golf ball layer. Examples
of non-ionomeric polymers include vinyl resins, polyolefins
including those produced using a single-site catalyst or a
metallocene catalyst, polyurethanes, polyureas, polyamides,
polyphenylenes, polycarbonates, polyesters, polyacrylates,
engineering thermoplastics, and the like.
[0090] Olefin-based ionomers, such as ethylene-based copolymers,
normally include an unsaturated carboxylic acid, such as
methacrylic acid, acrylic acid, or maleic acid. Other possible
carboxylic acid groups include, for example, crotonic, maleic,
fumaric, and itaconic acid. "Low acid" and "high acid" olefin-based
ionomers, as well as blends of such ionomers, may be used. In
general, low acid ionomers are considered to be those containing 16
wt. % or less of carboxylic acid, whereas high acid ionomers are
considered to be those containing greater than 16 wt. % of
carboxylic acid. The acidic group in the olefin-based ionic
copolymer is partially or totally neutralized with metal ions such
as zinc, sodium, lithium, magnesium, potassium, calcium, manganese,
nickel, chromium, copper, or a combination thereof. For example,
ionomeric resins having carboxylic acid groups that are neutralized
from about 10 percent to about 100 percent may be used. In one
embodiment, the acid groups are partially neutralized. That is, the
neutralization level is from 10 to 80%, more preferably 20 to 70%,
and most preferably 30 to 50%. In another embodiment, the acid
groups are highly or fully neutralized. Or, the neutralization
level may be from about 80 to 100%, more preferably 90 to 100%, and
most preferably 95 to 100%. The blend may contain about 5 to about
30% by weight of the renewable component composition and about 95
to about 70% by weight of a partially, highly, or fully-neutralized
olefin-based ionomeric copolymer. The above-mentioned blends may
contain one or more suitable compatibilizers such as glycidyl
acrylate or glycidyl methacrylate or maleic anhydride
containing-polymers.
[0091] In the present invention, the surface hardness of a core is
obtained from the average of a number of measurements taken from
opposing hemispheres of a core, taking care to avoid making
measurements on the parting line of the core or on surface defects,
such as holes or protrusions. Hardness measurements are made
pursuant to ASTM D-2240 "Indentation Hardness of Rubber and Plastic
by Means of a Durometer." Because of the curved surface of a core,
care must be taken to insure that the core is centered under the
durometer indentor before a surface hardness reading is obtained. A
calibrated, digital durometer, capable of reading to 0.1 hardness
units is used for all hardness measurements and is set to take
hardness readings at 1 second after the maximum reading is
obtained. The digital durometer must be attached to, and its foot
made parallel to, the base of an automatic stand, such that the
weight on the durometer and attack rate conform to ASTM D-2240.
[0092] To prepare a core for hardness gradient measurements, the
core is gently pressed into a hemispherical holder having an
internal diameter approximately slightly smaller than the diameter
of the core, such that the core is held in place in the
hemispherical portion of the holder while concurrently leaving the
geometric central plane of the core exposed. The core is secured in
the holder by friction, such that it will not move during the
cutting and grinding steps, but the friction is not so excessive
that distortion of the natural shape of the core would result. The
core is secured such that the parting line of the core is roughly
parallel to the top of the holder. The diameter of the core is
measured 90 degrees to this orientation prior to securing. A
measurement is also made from the bottom of the holder to the top
of the core to provide a reference point for future calculations. A
rough cut, made slightly above the exposed geometric center of the
core using a band saw or other appropriate cutting tool, making
sure that the core does not move in the holder during this step.
The remainder of the core, still in the holder, is secured to the
base plate of a surface grinding machine. The exposed `rough` core
surface is ground to a smooth, flat surface, revealing the
geometric center of the core, which can be verified by measuring
the height of the bottom of the holder to the exposed surface of
the core, making sure that exactly half of the original height of
the core, as measured above, has been removed to within .+-.0.004
inches.
[0093] Leaving the core in the holder, the center of the core is
found with a center square and carefully marked and the hardness is
measured at the center mark. Hardness measurements at any distance
from the center of the core may be measured by drawing a line
radially outward from the center mark, and measuring and marking
the distance from the center, typically in 2-mm increments. All
hardness measurements performed on the plane passing through the
geometric center are performed while the core is still in the
holder and without having disturbed its orientation, such that the
test surface is constantly parallel to the bottom of the holder.
The hardness difference from any predetermined location on the core
(e.g., first outer surface, second outer surface, etc.) is
calculated as the average hardness at the predetermined location
minus the hardness at a chosen reference point at or closer to the
geometric center than the predetermined location. For example, if
the predetermined location is the second outer surface and is
softer than its reference point, the inner surface, a negative
hardness gradient results between the two points. Conversely, if
inner surface is harder than the second outer surface, a positive
hardness gradient results.
[0094] Hardness with respect to intermediate and cover layers may
refer to surface hardness.
[0095] Golf ball compression remains an important factor to
consider in maximizing playing performance. It affects the ball's
spin rate off the driver as well as the feel. Initially,
compression was referred to as the tightness of the windings around
a golf ball. Today, compression refers to how much a ball will
deform under a compressive force when a driver hits the ball. A
ball actually tends to flatten out when a driver meets the ball; it
deforms out of its round shape and then returns to its round shape,
all in a second or two. Compression ratings of from about 70 to
about 120 are common. The lower the compression rating, the more
the ball will compress or deform upon impact.
[0096] People with a slower swing or slower club head speed will
desire a ball having a lower compression rating. While the
compression of a ball alone does not determine whether a ball flies
farther--the club head speed actually determines that--compression
can nevertheless influence or contribute to overall distance. For
example, a golfer with a slower club head speed who uses a high
compression ball will indeed lose yardage that would otherwise be
achieved if that golfer used a low compression (or softer) ball.
Accordingly, it is desirable to match golf ball compression rating
with a player's swing speed in maximizing a golfer's performance on
the green.
[0097] Several different methods can be used to measure
compression, including Atti compression, Riehle compression,
load/deflection measurements at a variety of fixed loads and
offsets, and effective modulus. See, e.g., Compression by Any Other
Name, Science and Golf IV, Proceedings of the World Scientific
Congress of Golf (Eric Thain ed., Routledge, 2002) ("J. Dalton")
The term compression, as used herein, refers to Atti compression
and is measured using an Atti compression test device. A piston
compresses a ball against a spring and the piston remains fixed
while deflection of the spring is measured at 1.25 mm (0.05
inches). Where a core has a very low stiffness, the compression
measurement will be zero at 1.25 mm. In order to measure the
compression of a core using an Atti compression tester, the core
must be shimmed to a diameter of 1.080 inches because these testers
are designed to measure objects having that diameter. Atti
compression units can be converted to Riehle (cores), Riehle
(balls), 100 kg deflection, 130-10 kg deflection or effective
modulus using the formulas set forth in J. Dalton.
[0098] According to one aspect of the present invention, the golf
ball is formulated to have a compression of from about 50 to about
120. In one embodiment, the compression of the core is greater than
about 50. In another embodiment, the compression of the core is
greater than about 70. In yet another embodiment, the compression
of the core is from about 80 to about 100.
[0099] The distance that a golf ball would travel upon impact is a
function of the coefficient of restitution (COR) and the
aerodynamic characteristics of the ball. For golf balls, COR has
been approximated as a ratio of the velocity of the golf ball after
impact to the velocity of the golf ball prior to impact. The COR
varies from 0 to 1.0. A COR value of 1.0 is equivalent to a
perfectly elastic collision, that is, all the energy is transferred
in the collision. A COR value of 0.0 is equivalent to a perfectly
inelastic collision--that is, all of the energy is lost in the
collision.
[0100] COR, as used herein, is determined by firing a golf ball or
golf ball subassembly (e.g., a golf ball core) from an air cannon
at two given velocities and calculating the COR at a velocity of
125 ft/s. Ball velocity is calculated as a ball approaches
ballistic light screens which are located between the air cannon
and a steel plate at a fixed distance. As the ball travels toward
the steel plate, each light screen is activated, and the time at
each light screen is measured. This provides an incoming transit
time period inversely proportional to the ball's incoming velocity.
The ball impacts the steel plate and rebounds through the light
screens, which again measure the time period required to transit
between the light screens. This provides an outgoing transit time
period inversely proportional to the ball's outgoing velocity. COR
is then calculated as the ratio of the outgoing transit time period
to the incoming transit time period,
COR=V.sub.out/V.sub.in=T.sub.in/T.sub.out. Preferably, a golf ball
according to the present invention has a COR of at least about
0.78, more preferably, at least about 0.80.
[0101] The spin rate of a golf ball also remains an important golf
ball characteristic. High spin rate allows skilled players more
flexibility in stopping the ball on the green if they are able to
control a high spin ball. On the other hand, recreational players
often prefer a low spin ball since they do not have the ability to
intentionally control the ball, and lower spin balls tend to drift
less off the green.
[0102] Golf ball spin is dependent on variables including, for
example, distribution of the density or specific gravity within a
golf ball. For example, when the density or specific gravity is
located in the golf ball center, a lower moment of inertia results
which increases spin rate. Alternatively, when the density or
specific gravity is concentrated in the outer regions of the golf
ball, a higher moment of inertia results with a lower spin rate.
The moment of inertia for a one piece ball that is 1.62 ounces and
1.68 inches in diameter is approximately 0.4572 oz-in.sup.2, which
is the baseline moment of inertia value.
[0103] Accordingly, by varying the materials and the hardness of
the regions of each core layer, different moments of inertia may be
achieved for the golf ball of the present invention. In one
embodiment, the resulting golf ball has a moment of inertia of from
about to 0.440 to about 0.455 oz-in.sup.2. In another embodiment,
the golf balls of the present invention have a moment of inertia of
from about 0.456 oz-in.sup.2 to about 0.470 oz-in.sup.2. In yet
another embodiment, the golf ball has a moment of inertia of from
about 0.450 oz-in.sup.2 to about 0.460 oz-in.sup.2.
[0104] In one embodiment, the UHMWPHA composition of the present
invention has a moisture vapor transmission rate ("MVTR") of 10
gmil/100 in.sup.2/day or less, preferably 8 or less, more
preferably 2 or less. As used herein, MVTR is given in gmil/100
in.sup.2/day, and is measured at 20.degree. C., according to ASTM
F1249-99.
[0105] By way of non-limiting prophetic example, a golf ball
according to the invention may be made as follows:
The Core:
[0106] A golf ball core of the present invention can be made using
the ingredients as shown in Table I below. As used herein, the term
"phr" represents parts per hundred parts by weight of rubber.
TABLE-US-00001 TABLE 1 Core Compositions for 1.550'' diameter Core
Ingredients Comparative (phr) Example 1 Example 1 Example 2 Example
3 Polybutadiene 100 100 100 100 rubber, Taktene .RTM. 220 Peroxide
0.8 0.8 0.8 0.8 initiator, Perkadox BC- FF * Co-agent, SR- 30 30 30
30 526 ** ZnO 5 5 5 5 Density 20 20 20 20 adjusting filler,
BaSO.sub.4 UHMWPHA 0 5 10 15 having a melt index of 5.0 at 210
.degree. C./2.16 Kg and a Vicat softening temperature of 180
.degree. F. Perkadox BC-FF *: Dicumyl peroxide (99 to 100% active)
available from Akzo Nobel SR-526 **: Zinc diacrylate available from
Sartomer
[0107] Referring to Table I, the composition of the core in
comparative example 1 is identical to that of the cores in Examples
1, 2 and 3 except that the comparative example 1 core comprises no
UHMWPHA. In contrast, the cores of Examples 1, 2 and 3 in Table I
comprise varying amounts of UHMWPHA as indicated in addition to the
co-agent. A core as reflected in Examples 1, 2 and 3 would possess
higher compression and improved flight characteristics over the
core of Comparative Example 1.
[0108] Although the co-agent provides stiffening similar to the
UHMWPHA, and would provide resilience and impact durability, the
UHMWPHA also possesses biodegradable characteristics as a renewable
resource, whereas the co-agent does not. Moreover, while
Comparative Example 1 and Examples 1, 2 and 3 of Table I each
include 30 phr co-agent, a further inventive core is envisioned
which includes less co-agent than does Comparative Example 1 (for
example 25 phr) and meanwhile includes an UHMWPHA in an amount
which would nevertheless retain or increase resilience and
compression as compared with the core of Comparative Example 1
having 30 phr co-agent.
[0109] Additionally, where a core comprises the ingredients
represented in Table I, these ingredients may be included in
amounts within the following ranges (phr):
[0110] Polybutadiene rubber, Taktene.RTM. 220: 100
[0111] Peroxide initiator, Perkadox BC-FF: from about 0.4 to about
2.0, preferably from about 0.5 to about 1.4, most preferably from
about 0.6 to about 1.2
[0112] Co-agent, SR-526: from about 20 to about 45, preferably from
about 24 to about 40, most preferably from about 28 to about 36
[0113] ZnO: from about 2 to about 20
[0114] Density adjusting filler, BaSO.sub.4: from about 5 to about
50, or from about 10 to about 40 and most preferably from about 15
to about 30
[0115] UHMWPHA: from about 5 to about 50, preferably from about 5
to about 40 and most preferably from about 5 to about 30
[0116] When the Vicat softening temperature of the UHMWPHA is below
150.degree. F., conventional rubber mixing equipment such as a roll
mill/internal mixer/extruder may be used to make golf cores.
However, when the Vicat softening temperature of the UHMWPHA is
above 150.degree. F., then it is preferable to blend a diene rubber
and the UHMWPHA together using a single or twin-screw compounding
machine to produce a homogeneous polymer blend at a mixing
temperature of up to about 450.degree. F. in order to prevent any
degradation of the diene rubber during the mixing process. To this
blend, the remaining ingredients as disclosed in Table 1 may be
added and mixed uniformly on a roll mill or other rubber processing
equipment at a temperature not exceeding about 200.degree. F. to
prevent any cross-linking prior to core molding. In one embodiment,
the core molding may be performed at 350.degree. F. for 11 minutes
when a dicumyl peroxide initiator is used by any compression
molding procedure known in the golf ball art. Furthermore, other
core molding techniques including a one step or a multi-step curing
can be employed to provide desirable golf ball core performance
including increased CoR at lower compression. Optionally, the core
formulations may include an antioxidant such as Vanox.RTM. MBPC to
provide a negative or zero gradient in hardness properties (as
disclosed for example in U.S. Pat. No. 7,678,312).
Inner Cover and/or Intermediate Layer:
[0117] A golf ball inner cover or intermediate layer of the
invention can be made using the ingredients as shown in Table II.
As used in Table II, the term "phr" represents parts per hundred
parts by weight of resin.
TABLE-US-00002 TABLE II Inner Cover Compositions Ingredients
Comparative (phr) Example 2 Example 4 Example 5 Example 6 Surlyn
.RTM. 9910*** 100 100 100 100 UHMWPHA 0 5 10 15 having a melt index
of 5.0 at 210 .degree. C./2.16 Kg ***Surlyn .RTM. 9910 is a Zinc
ionomer from Du Pont.
[0118] Referring to Table II, these ingredients may be combined as
a physical mixture (salt and pepper like) for an injection molding
process directly or can be compounded using a single or twin-screw
compounding machine. The compounded composition may be injection
molded as an inner cover layer having a thickness in the range of
from about 0.010 inches to about 0.050 inches, preferably from
about 0.020 inches to about 0.040 inches and most preferably from
about 0.025 inches to 0.030 inches either by making half shells
followed by compression molding or by using a retractable pin
injection molding (RPIM) process known in the golf ball art. An
inner cover/intermediate layer as reflected in Examples 4, 5 and 6
would possess higher stiffness and reduced backspin from the driver
as well as provide biodegradability as compared with that of
Comparative Example 2. Alternatively, the inner cover or
intermediate layer may include an UHMWPHA in an amount within the
same ranges as disclosed above with respect to the core
composition.
Outer Cover:
[0119] A golf ball outer cover of the present invention can be made
using the ingredients as shown in Table III:
TABLE-US-00003 TABLE III Outer Cover Compositions Ingredients
Comparative (phr) Example 3 Example 7 Example 8 Example 9
Thermoplastic 100 100 100 100 Urethane Estane .RTM. 58134****
UHMWPHA 0 5 10 15 having a melt index of 5.0 at 210.degree. C./2.16
Kg ****Estane .RTM. is a thermoplastic urethane from Lubrizol
Corporation
[0120] Referring to Table III, these ingredients may be combined as
a physical mixture (salt and pepper like) for an injection molding
process directly or can be compounded using a single or twin-screw
compounding machine. The compounded composition is injection molded
as a golf ball outer cover layer either by making half shells
followed by compression molding or by RPIM process known in the
golf ball art. Furthermore, other techniques such as a co-injection
molding method can be employed to produce a very soft outer skin
and a very thin hard middle layer based on the UHMWPHA
compositions. The covers in Examples 7, 8 and 9 of Table III would
possess higher stiffness and reduced backspin from the driver as
well as provide biodegradability as compared with that of
Comparative Example 3 of Table III. The outer cover may
alternatively include an UHMWPHA in an amount within the same
ranges disclosed hereinabove with respect to the core composition,
inner cover and intermediate layers.
[0121] Unless otherwise expressly specified, all of the numerical
ranges, amounts, values and percentages such as those for amounts
of materials, and others in the specification may be read as if
prefaced by the word "about" even though the term "about" may not
expressly appear with the value, amount or range. Accordingly,
unless indicated to the contrary, the numerical parameters set
forth in the specification and attached claims are approximations
that may vary depending upon the desired properties sought to be
obtained by the present invention. At the very least, and not as an
attempt to limit the application of the doctrine of equivalents to
the scope of the claims, each numerical parameter should at least
be construed in light of the number of reported significant digits
and by applying ordinary rounding techniques.
[0122] 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.
[0123] While it is apparent that the illustrative embodiments of
the invention disclosed herein fulfill the preferred embodiments of
the present invention, it is appreciated that numerous
modifications and other embodiments may be devised by those skilled
in the art. Examples of such modifications include reasonable
variations of the numerical values and/or materials and/or
components discussed above. Hence, the numerical values stated
above and claimed below specifically include those values and the
values that are approximate to those stated and claimed values.
Therefore, it will be understood that the appended claims are
intended to cover all such modifications and embodiments, which
would come within the spirit and scope of the present
invention.
[0124] 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. Indeed, various
modifications of the invention in addition to those shown and
described herein will become apparent to those skilled in the art
from the foregoing description. For example, the compositions of
the present invention may be used in a variety of equipment. Such
modifications are also intended to fall within the scope of the
appended claims.
[0125] While any of the embodiments herein may have any known
dimple number and pattern, a preferred number of dimples is 252 to
456, and more preferably is 330 to 392. The dimples may comprise
any width, depth, and edge angle disclosed in the prior art and the
patterns may comprises multitudes of dimples having different
widths, depths and edge angles. The parting line configuration of
said pattern may be either a straight line or a staggered wave
parting line (SWPL). Most preferably the dimple number is 330, 332,
or 392 and comprises 5 to 7 dimples sizes and the parting line is a
SWPL.
[0126] In any of these embodiments the single-layer core may be
replaced with a two or more layer core wherein at least one core
layer has a negative hardness gradient. Other than in the operating
examples, or unless otherwise expressly specified, all of the
numerical ranges, amounts, values and percentages such as those for
amounts of materials and others in the specification may be read as
if prefaced by the word "about" even though the term "about" may
not expressly appear with the value, amount or range.
[0127] Accordingly, unless indicated to the contrary, the numerical
parameters set forth in the specification and attached claims are
approximations that may vary depending upon the desired properties
sought to be obtained by the present invention. At the very least,
and not as an attempt to limit the application of the doctrine of
equivalents to the scope of the claims, each numerical parameter
should at least be construed in light of the number of reported
significant digits and by applying ordinary rounding
techniques.
[0128] While it is apparent that the illustrative embodiments of
the invention disclosed herein fulfill the objective stated above,
it is appreciated that numerous modifications and other embodiments
may be devised by those skilled in the art. Therefore, it will be
understood that the appended claims are intended to cover all such
modifications and embodiments, which would come within the spirit
and scope of the present invention.
* * * * *