U.S. patent application number 13/117366 was filed with the patent office on 2012-11-29 for golf balls incorporating cerium oxide nanoparticles.
Invention is credited to Randy Petrichko, Shawn Ricci.
Application Number | 20120302372 13/117366 |
Document ID | / |
Family ID | 47219597 |
Filed Date | 2012-11-29 |
United States Patent
Application |
20120302372 |
Kind Code |
A1 |
Ricci; Shawn ; et
al. |
November 29, 2012 |
GOLF BALLS INCORPORATING CERIUM OXIDE NANOPARTICLES
Abstract
The invention is directed to a golf ball providing improved UV
resistance, abrasion resistance and hydrophobicity comprising
cerium oxide nanoparticles having a particle size within the
wavelength of visible light. The golf ball of the invention may
comprise the cerium oxide nanoparticles in any or all of outer core
layers, intemiediate layers, inner cover layers, outer cover layers
and even as a coating composition in an amount of from about 0.5 wt
% to about 10 wt % of the respective layer. The cerium oxide
nanoparticles may be randomly dispersed within a layer or coating,
or alternatively, the cerium oxide nanoparticles may be ordered in
an array within the layer or coating.
Inventors: |
Ricci; Shawn; (New Bedford,
MA) ; Petrichko; Randy; (Richmond, RI) |
Family ID: |
47219597 |
Appl. No.: |
13/117366 |
Filed: |
May 27, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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13117228 |
May 27, 2011 |
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13117366 |
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Current U.S.
Class: |
473/372 ;
473/385 |
Current CPC
Class: |
A63B 37/0024 20130101;
A63B 37/0003 20130101; A63B 2209/00 20130101; A63B 37/12
20130101 |
Class at
Publication: |
473/372 ;
473/385 |
International
Class: |
A63B 37/02 20060101
A63B037/02; A63B 37/12 20060101 A63B037/12 |
Claims
1. A golf ball comprising a core, a cover and optionally an
intermediate layer disposed between the core and the cover, wherein
at least one of the core and the intermediate layer comprises a
moisture barrier layer that is formed from a water vapor barrier
composition consisting of from about 0.5 wt % to about 10 wt % of
cerium oxide nanoparticles having a particle size of from about 370
nm to about 800 nm, wherein the vapor barrier composition has a
moisture vapor transmission rate of from about 0.45
gramsmm/m.sup.2day to about 1.5 gramsmm/m.sup.2day.
2. (canceled)
3. The golf ball of claim 1, wherein the wavelength of visible
light is from about 400 nm to about 700 nm.
4. The golf ball of claim 1, wherein the wavelength of visible
light is from about 380 nm to about 500 nm.
5. The golf ball of claim 1, wherein the wavelength of visible
light is from about 500 nm to about 700 nm.
6. (canceled)
7. The golf ball of claim 1, wherein the at least one of the core
and the intermediate layer comprises the cerium oxide nanoparticles
in an amount of from about 1.0 wt % to about 4.0 wt %.
8. A golf ball comprising a core, a cover and an intermediate layer
disposed between the core and the cover wherein at least one of the
intermediate layer and the cover is formed from a moisture vapor
barrier composition comprising cerium oxide nanoparticles having a
particle size within the wavelength of visible light, wherein the
cerium oxide nanoparticles are randomly dispersed within the
moisture barrier composition.
9. The golf ball of claim 8, wherein the vapor barrier composition
has a moisture vapor transmission rate of from about 0.45
gramsmm/m.sup.2day to about 1.5 gramsmm/m.sup.2day.
10. The golf ball of claim 8, wherein the vapor barrier composition
has a moisture vapor transmission rate of about 0.95
gramsmm/m.sup.2day or greater.
11. (canceled)
12. A golf ball comprising a core having an untreated region and a
treated outer surface, the treated outer surface having a first
moisture vapor transmission rate and the untreated region having a
second moisture vapor transmission rate, the treated outer surface
being treated with a moisture vapor barrier composition comprising
cerium oxide nanoparticles having a particle size within the
wavelength of visible light, and wherein the first moisture vapor
transmission rate is lower than the second moisture vapor
transmission rate.
13. A golf ball comprising a core and a cover disposed about the
core, wherein the cover comprises an inner surface and an outer
surface, said inner surface being treated with a composition
comprising cerium oxide nanoparticles having a particle size of
from about 370 nm to about 800 nm such that a moisture vapor
transmission rate X of the inner surface is lower than a moisture
vapor transmission rate Y of the outer surface.
14. A golf ball comprising a core and a cover disposed about the
core, wherein the cover comprises an inner cover layer and an outer
cover layer, said inner cover layer having a moisture vapor
transmission rate X and the outer cover layer having a moisture
vapor transmission rate Y, the outer cover layer comprising a
moisture vapor barrier composition formed from a composition
comprising cerium oxide nanoparticles having a particle size of
from about 370 nm to about 800 nm such that X>Y.
15. The golf ball of claim 14, wherein Y.ltoreq.0.75X.
16. The golf ball of claim 14, wherein Y.ltoreq.0.5X.
17. The golf ball of claim 14, wherein Y.ltoreq.0.25X.
18. The golf ball of claim 14, wherein Y.ltoreq.0.10X.
19. The golf ball of claim 14, wherein Y.ltoreq.0.95X.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of co-pending U.S. patent
application Ser. No. 13/117,228, filed May 27, 2011.
FIELD OF THE INVENTION
[0002] Golf balls incorporating materials which improve UV
resistance, abrasion resistance and hydrophobicity.
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] Notwithstanding a golf ball's particular construction, it is
important that the golf ball appear and remain aesthetically
pleasing to golfers. In this regard, preserving a white pigmented
golf ball's color conveys high product quality and reliability over
a white golf ball which yellows or browns over time from exposure
to light, in particular, ultraviolet (UV) light. Yellowing is a
common problem in golf ball covers made of thermoset or
thermoplastic polyurethanes or polyureas due to the presence of an
aromatic component in each--e.g., aromatic diisocyanate, polyol, or
polyamine.
[0005] Previously, manufacturers have addressed golf ball cover
yellowing by incorporating UV blockers, absorbers or light
stabilizers in the cover and even by modifying the polyurethanes or
polyureas themselves. In one approach, manufacturers disclose
surface-treating TiO.sub.2 with oxides, such as CeO.sub.2, before
adding the TiO.sub.2 into a cover formulation in order to suppress
photocatalytic action, which is inherent to aluminum oxide. See
U.S. Pat. No. 7,207,904 of Isogawa et al. ("the '904 patent").
Under UV illumination, absorption of a photon with a higher energy
than the bond gap creates an electron-hole pair in both TiO.sub.2
and CeO.sub.2. But since TiO.sub.2 has less localized electrons (3
d orbital) than CeO.sub.2 (4 f orbital), TiO.sub.2 electron-hole
pairs migrate to the surface of TiO.sub.2 particles rather than
recombining together inside the particle. Then, when electrons and
holes migrate to the surface, they react with oxygen, water or
hydroxyls to form free radicals which cause polymeric degradation,
resulting in yellowing of an otherwise white cover surface. In the
'904 patent, the degradation associated with a TiO.sub.2 is reduced
by either forming a layer containing cerium oxide around each
titanium oxide particle or adhering fine particles containing
cerium oxide on the surface of the titanium oxide. See the '904
patent, e.g., at col. 3, lines 40-53, FIG. 1 and FIG. 2.
[0006] Golf ball manufacturers have also incorporated cerium oxide
nanoparticles having particle sizes of from about 1 nm to about 50
nm (0.001.mu.-0.05.mu.) in cover "color traveling" coating
formulations to increase the difference in refractive index between
a polymer matrix and particles added to the matrix when the
difference is not great enough to achieve the desired effect of
perceived varying color. See e.g. U.S. Pat. No. 7,220,192 of Andre
et al. at col. 6, lines 20-29. Particle sizes of 1 nm to about 50
nm (0.001.mu. to about 0.05.mu.), being less than the wavelength of
visible light (about 370 nm to about 800 nm (about 0.37.mu.-about
0.80.mu.)), do not substantially reflect or scatter light. Id.
[0007] at co. 6, lines 27-29.
[0008] However, it would be advantageous if a cerium oxide particle
sizes could be identified which preserve the whiteness of a golf
ball cover independently and irrespective of the presence/absence
or positioning of titanium oxide particles or any other pigment or
colorant in the composition.
[0009] Meanwhile, durability--that is, a scuff and/or abrasion
resistance--remains a further concern which directly affects the
aesthetics of the golf ball. A scuff and/or abrasion resistant
cover presents the player with apparently high quality and
attractive golf ball. Golf ball manufacturers have found it
challenging to address this aesthetic aspect without compromising
the "soft feel" desired by players. There remains a need for golf
ball cover composed of or coated with versatile materials which not
only reduce yellowing but simultaneously improve scuff/abrasion
resistance, without substantially impacting the soft feel.
[0010] Meanwhile, it is desirably cost effective for golf ball
manufacturers to find solutions to "aesthetics" related golf ball
issues which also address and resolve "performance" related issues
such as moisture penetration into the golf ball. Moisture
penetration issues typically arise, for example, when golf ball
manufacturers use polybutadiene cores cross-linked with peroxide
and/or zinc diacrylate in the golf ball core. The core is the
"engine" of the golf ball when hit with a club head--that is, the
spring of the ball and its principal source of resiliency. Water
moisture vapor reduces the resiliency of the core and degrades its
properties. Thus, preferably a golf ball core is covered quickly to
maintain and preserve optimum golf ball properties.
[0011] Intermediate layers of the golf ball 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
typically protects the core from repeated impacts from golf clubs,
but may also act as a moisture barrier or be coated to serve as
one. The cover may be made from ionomer resins, balata, and
urethane, among other materials. The ionomer covers, particularly
the harder ionomers, offer some protection against penetration of
water vapor. However, it is more difficult to control or impart
spin to balls with hard covers. Conventional urethane covers, on
the other hand, while providing better ball control due to
increased spin, offer less resistance to water vapor than ionomer
covers.
[0012] The golf ball may also comprise additional layers, such as
an outer core layer or an inner cover layer--often to increase the
resiliency of the ball but also may serve to protect the core or
inner core from moisture infiltration.
[0013] Prolonged exposure to high humidity and elevated temperature
may be sufficient to allow water vapor to invade and permeate the
cores of some commercially available golf balls. For example at
110.degree. F. and 90% humidity for a sixty day period, significant
amounts of moisture enter the cores and reduce the initial velocity
of the balls by 1.8 ft/s to 4.0 ft/s or greater. The absorbed water
vapor will decrease core compression by about 5 to about 10 units
and also reduce the coefficient of restitution (COR) of the
ball.
[0014] Commonly owned U.S. Pat. No. 6,632,147 B2 broadly suggests
incorporating "nanoparticles" in barrier layers for increasing the
layer's resistance to the transmission of moisture through the
layer. Still, there is a need to identify specific hydrophobic
nanoparticle-containing materials which serve as particularly
protective encasing layers (outer core, intermediate, inner cover,
outer cover) and/or coatings which impart improved moisture
penetration resistance to the molded layer thereby preserving,
maintaining and/or enhancing optimum golf ball properties and
desired golf ball characteristics such as spin, resilience and
durability.
[0015] To date, manufacturers have found it difficult to
simultaneously improve/preserve aesthetic qualities and address
issues affecting player performance. Accordingly, a golf ball
having a cover incorporating a versatile material which
simultaneously provides the advantages of UV resistance,
abrasion/scuff resistance and hydrophobicity would be useful as
reducing manufacturing costs since that material could be included
in a wide range of golf ball applications in any or all of outer
core layers, intermediate layers, inner cover layers, outer cover
layers and as a coating composition.
SUMMARY OF THE INVENTION
[0016] The golf balls of the invention address and resolve all of
the concerns identified above providing improved UV resistance
(i.e., reduced yellowing), as well as better abrasion resistance
and hydrophobicity. The invention is directed to a golf ball
comprising cerium oxide nanoparticles having a particle size within
the wavelength of visible light. The golf ball of the invention may
comprise the cerium oxide nanoparticles in any or all of outer core
layers, intermediate layers, inner cover layers, outer cover layers
and even as a coating composition. One or more of these golf ball
components may comprise a thermoset or thermoplastic composition
comprising the cerium oxide nanoparticles. Alternatively, the
thermoset or thermoplastic composition may comprise a cerium oxide
composition consisting essentially of cerium oxide nanoparticles
having a particle size within the wavelength of visible light.
[0017] Also, the cerium oxide composition may consist of cerium
oxide nanoparticles having a particle size within the wavelength of
visible light.
[0018] The wavelength of visible light, as defined herein, may be
from about 370 nm to about 800 nm, or from about 370 nm to about
750 nm, or from about 400 nm to about 800 nm, or from about 400 nm
to about 750 nm, or from about 380 nm to about 750 nm, or from
about 400 nm to about 700 nm, or from about 625 nm to about 740, or
from about 590 nm to about 625 nm, or from about 565 nm to about
590 nm, or from about 520 nm to about 565 nm, or from about 500 nm
to about 520, or from about 435 to about 500 nm, or from about 380
nm to about 435 nm. Accordingly, the cerium oxide nanoparticles may
have a particle size within any of these wavelength ranges.
[0019] In one embodiment, the golf ball comprises a core layer, a
cover layer and optionally an intermediate layer disposed between
the core and the cover, wherein the cover layer comprises a
thermoset or theromoplastic composition comprising a substantially
homogeneous particulate consisting of cerium oxide nanoparticles
having a particle size of from about 370 nm to about 800 nm.
[0020] In another embodiment, the cover layer comprises a thermoset
or theromoplastic composition comprising cerium oxide nanoparticles
having a particle size of from about 370 nm to about 800 nm,
wherein the cerium oxide nanoparticles are randomly dispersed
within the thermoset or theromoplastic composition. In another
embodiment, the cover layer comprises cerium oxide nanoparticles
which are randomly dispersed within the thermoset or theromoplastic
composition independently of titanium oxide and/or a plurality of
titanium oxide particles distributed within the thermoset or
theromoplastic composition. In yet another embodiment, the cerium
oxide nanoparticles are randomly dispersed within the thermoset or
theromoplastic composition independently of a pigment distributed
within the thermoset or theromoplastic composition.
[0021] In still another embodiment, the cover layer comprises a
thermoset or theromoplastic composition comprising cerium oxide
nanoparticles having a particle size of from about 370 nm to about
770 nm, wherein the cerium oxide nanoparticles are ordered in an
array within the thermoset or theromoplastic composition.
Alternatively, the cover layer comprises a thermoset or
theromoplastic composition comprising cerium oxide nanoparticles
having a particle size of from about 370 nm to about 800 nm,
wherein the cerium oxide nanoparticles are ordered in an array
within the thermoset or theromoplastic composition independently of
a plurality of titanium oxide particles distributed within the
thermoset or theromoplastic composition. Also, the cerium oxide
nanoparticles are ordered in an array within the thermoset or
theromoplastic composition independently of a plurality of a
pigment distributed within the thermoset or theromoplastic
composition.
[0022] In another aspect of the invention, golf ball comprises a
core layer, a cover layer and optionally an intermediate layer
disposed between the core and the cover, wherein the cover layer
comprises a thermoset or theromoplastic composition comprising a
prepolymer, a curing agent, a white pigment, and from about 1 wt %
to about 4 wt % of a substantially homogeneous particulate
consisting of cerium oxide nanoparticles having a particle size of
from about 370 nm to about 800 nm, said substantially homogeneous
particulate being randomly dispersed within the thermoset or
theromoplastic composition.
[0023] The cover layer may alternatively be formed from a thermoset
or theromoplastic composition comprising: (1) a prepolymer mixture
comprising a substantially homogenous particulate consisting of
titanium oxide; (2) a curing agent; and (3) from about 1 wt % to
about 4 wt % of a substantially homogeneous particulate consisting
of cerium oxide nanoparticles having a particle size of from about
370 nm to about 800 nm.
[0024] Instead, the cover layer is formed from a thermoset or
theromoplastic composition comprising: (1) a prepolymer; (2) a
curing agent comprising a substantially homogenous particulate
consisting of titanium oxide; and (3) from about 1 wt % to about 4
wt % of a substantially homogeneous particulate consisting of
cerium oxide nanoparticles having a particle size of from about 370
nm to about 770 nm.
[0025] In another embodiment,the cover layer comprises a thermoset
or theromoplastic composition comprising a prepolymer; a curing
agent, a substantially homogenous particulate consisting
essentially of titanium oxide; and from about 1 wt % to about 4 wt
% of a substantially homogeneous particulate consisting essentially
of cerium oxide nanoparticles having a particle size of from about
370 nm to about 770 nm.
[0026] In yet another embodiment, the cover layer comprises a
thermoset or theromoplastic composition comprising a white
pigmented prepolymer, a curing agent, and from about 1 wt % to
about 4 wt % of a substantially homogeneous particulate consisting
of cerium oxide nanoparticles having a particle size of from about
370 nm to about 770 nm.
[0027] Also, the cover layer may comprise a thermoset or
theromoplastic composition comprising a prepolymer, a white
pigmented curing agent, and from about 1 wt % to about 4 wt % of a
substantially homogeneous particulate consisting of cerium oxide
nanoparticles having a particle size of from about 370 nm to about
770 nm.
[0028] Further, the golf ball may comprise a core and a cover
disposed about the core wherein the cover comprises an inner
surface and an outer surface, said outer surface being treated with
and comprising a light stabilizing composition comprising cerium
oxide nanoparticles having a particle size of from about 370 nm to
about 770 nm.
[0029] The light stability of a cover may be quantified by the
difference in yellowness index .DELTA.Yl, that is, yellowness
measured after a predetermined exposure time minus yellowness
before exposure. In one embodiment, the .DELTA.Yl for the cover of
the golf ball of the invention is less than about 12.0 after 5
days. In another embodiment, the .DELTA.Yl for the cover of the
golf ball of the invention is less than about 11.0 after 5 days. In
yet another embodiment, the .DELTA.Yl for the cover of the golf
ball of the invention is about 10.5 or less after 5 days. In still
another embodiment, the .DELTA.Yl for the cover of the golf ball of
the invention is about less than about 10 after 5 days.
[0030] In one embodiment, the .DELTA.Yl for the cover of the golf
ball of the invention is less than about 15.0 after 8 days. The
.DELTA.Yl for the cover of the golf ball of the invention is less
than about 13.5 after 8 days. In another embodiment, the .DELTA.Yl
for the cover of the golf ball of the invention is about 12.5 or
less after 8 days. In yet another embodiment, the .DELTA.Yl for the
cover of the golf ball of the invention is about 12.0 or less after
8 days.
[0031] Meanwhile, the difference in the b chroma dimension
.DELTA.b*, yellow to blue, is also a way to quantify the light
stability of a cover. In one embodiment, the .DELTA.b* for the
cover of the golf ball of the invention is less than about 8 after
5 days. In another embodiment, the .DELTA.b* for the cover of the
golf ball of the invention is about 6.75 or less after 5 days. In
yet another embodiment, the .DELTA.b* for the cover of the golf
ball of the invention is about 6.5 or less after 5 days. In still
another embodiment, the .DELTA.b* for the cover of the golf ball of
the invention is about 6.25 or less after 5 days or even 6.0 or
less after 5 days.
[0032] The .DELTA.b* for the cover of the golf ball of the
invention is about 9.5 or less after 8 days. In another embodiment,
the .DELTA.b* for the cover of the golf ball of the invention is
less than about 8.0 after 8 days. In yet another embodiment, the
.DELTA.b* for the cover of the golf ball of the invention is about
7.75 or less after 8 days. In still another embodiment, the
.DELTA.b* for the cover of the golf ball of the invention is about
7.25 or less after 8 days or even about 7.0 or less after 8
days.
[0033] For example, in one embodiment, .DELTA.Yl for the cover is
less than about 11.5 after 5 days; .DELTA.Yl for the cover is less
than about 13.5 after 8 days; .DELTA.b* for the cover is less than
about 7.5 after 5 days; and .DELTA.b* for the cover is about 8.5 or
less after 8 days. In another embodiment, .DELTA.Yl for the cover
is less than about 11.0 after 5 days; .DELTA.Yl for the cover is
about 13.0 or less after 8 days; .DELTA.b* for the cover is about
6.75 or less after 5 days; and .DELTA.b* for the cover is about
7.75 or less after 8 days. In yet another embodiment, .DELTA.Yl for
the cover is about 10.9 or less after 5 days; .DELTA.Yl for the
cover is about 12.6 or less after 8 days; .DELTA.b* for the cover
is about 6.60 or less after 5 days; and .DELTA.b* for the cover is
about 7.54 or less after 8 days. In still another embodiment,
.DELTA.Yl for the cover is less than about 14.0 after 5 days;
.DELTA.Yl for the cover is about 17.0 or less after 8 days;
.DELTA.b* for the cover is about 8.0 or less after 5 days; and
.DELTA.b* for the cover is about 9.5 or less after 8 days.
[0034] The golf ball of the invention may further comprise a core
layer, a cover layer and optionally an intermediate layer disposed
between the core and the cover, wherein at least one of the core,
the intermediate layer and the cover layer is formed from a
composition comprising a substantially homogenous cerium oxide
particulate consisting of nanoparticles having a particle size of
from about 370 nm to about 770 nm. In another embodiment, at least
one of the core layer and the intermediate layer comprises cerium
oxide nanoparticles having a particle size of from about 370 nm to
about 770 nm. In yet another embodiment, only the core layer
comprises the cerium oxide nanoparticles. In still another
embodiment, only the intermediate layer comprises the cerium oxide
nanoparticles.
[0035] In another aspect of the invention, the golf ball comprises
a core, a cover and an intermediate layer disposed between the core
and the cover wherein at least one of the intermediate layer and
the cover is formed from a moisture vapor barrier composition
comprising cerium oxide nanoparticles having a particle size of
from about 370 nm to about 800 nm. Alternatively, the core
comprises an outer core layer and only the outer core layer is
formed from the moisture vapor barrier composition. In yet another
embodiment, only the intermediate layer is framed from the moisture
vapor barrier composition.
[0036] In another aspect of the invention, the golf ball comprises
a core comprising an inner core layer and an outer core layer, a
cover and optionally an intermediate layer disposed between the
outer core layer and the cover wherein at least one of the outer
core layer and the intermediate layer is formed from a moisture
vapor barrier composition comprising cerium oxide nanoparticles
having a particle size of from about 1 nm to about 370 nm.
Alternatively, only the outer core layer is foinied from the
moisture vapor barrier composition. In yet another embodiment, only
the intermediate layer is formed from the moisture vapor barrier
composition.
[0037] In another embodiment, the golf ball comprises a core, a
cover and a moisture barrier layer disposed between the core and
the cover wherein the moisture vapor barrier layer has a moisture
vapor transmission rate that is lower than that of the cover and
the moisture vapor barrier layer is formed from a vapor barrier
composition comprising cerium oxide nanoparticles having a particle
size of from about 370 nm to about 800 nm
[0038] The moisture barrier layer may be an outer core layer, an
intermediate layer, an inner cover layer, outer cover layer or even
a coating.
[0039] The golf ball may also comprise a core comprising an
untreated region and a treated outer surface, the treated outer
surface having a first moisture vapor transmission rate and the
untreated region having a second moisture vapor transmission rate,
the treated outer surface being treated with a moisture vapor
barrier composition foimed from cerium oxide nanoparticles having a
particle size of from about 370 nm to about 800 nm such that the
first moisture vapor transmission rate is lower than the second
moisture vapor transmission rate.
[0040] In another embodiment, the golf ball comprises a core and a
cover disposed about the core wherein the cover comprises an inner
surface and an outer surface, said outer surface being treated with
a composition comprising cerium oxide nanoparticles having a
particle size of from about 370 nm to about 800 nm such that a
moisture vapor transmission rate X of the outer surface is lower
than a moisture vapor transmission rate Y of the inner surface.
[0041] In yet another embodiment, the golf ball comprises a core
and a cover disposed about the core wherein the cover comprises an
inner surface and an outer surface, said inner surface being
treated with a composition comprising cerium oxide nanoparticles
having a particle size of from about 370 nm to about 800 nm such
that a moisture vapor transmission rate X of the inner surface is
lower than a moisture vapor transmission rate Y of the inner
surface.
[0042] The golf ball mat also comprising a core and a cover
disposed about the core, wherein the cover comprises an inner cover
layer and an outer cover layer, said inner cover layer having a
moisture vapor transmission rate X and the outer cover layer having
a moisture vapor transmission rate Y, the outer cover layer
comprising a moisture vapor barrier composition formed from a
composition comprising cerium oxide nanoparticles having a particle
size of from about 370 nm to about 800 nm such that X>Y. In one
embodiment, Y.ltoreq.0.95X. In another embodiment, Y.ltoreq.0.75X.
In yet another embodiment, Y.ltoreq.0.5X. In still another
embodiment, Y.ltoreq.0.25X. In a further embodiment,
Y.ltoreq.0.10X.
[0043] The invention also relates to a method of manufacturing a
golf ball yielding reduced UV degradation and/or durability and/or
hydrophobicity. In one embodiment, the method comprises providing a
core and forming a cover material by providing a prepolymer;
combining the prepolymer with a curing agent and a white pigment to
form a castable cover formulation; and then randomly dispersing
into the castable cover formulation a substantially homogeneous
particulate consisting of cerium oxide nanoparticles having a
particle size of from about 370 nm to about 800 nm.
[0044] In another embodiment, the method comprises providing a core
and coating the core with a substantially homogeneous composition
consisting essentially of cerium oxide nanoparticles having a
particle size of from about 370 nm to about 800 nm, and forming a
cover about the coated core.
[0045] Another aspect of the invention is a method of making a golf
ball comprising: providing a core; forming a cover composition by
combining a prepolymer with a curing agent and a white pigment and
then randomly dispersing a substantially homogeneous particulate
consisting of cerium oxide nanoparticles having a particle size
within the wavelength of visible light into the cover composition;
and molding the cover about the core.
[0046] The method of making a golf ball may alternatively comprise
providing a core; coating the core with a substantially homogeneous
composition comprising cerium oxide nanoparticles having a particle
size of from about 370 nm to about 800 nm; and forming a cover
about the coated core.
[0047] Further, the method of manufacturing a golf ball may
comprise: forming a core having an inner core layer and an outer
core layer wherein said outer core layer comprises randomly
dispersed cerium oxide nanoparticles having a particle size of from
about 370 nm to about 800 nm; and forming a cover about the
core.
[0048] In a different embodiment, the method of manufacturing a
golf ball comprises: providing a core; forming an intermediate
layer about the core, said intermediate layer comprising randomly
dispersed cerium oxide nanoparticles having a particle size of from
about 370 nm to about 800 nm; and forming a cover about the
core.
[0049] In yet a different embodiment, the method of manufacturing a
golf ball comprises providing a core; providing a cover material
formed by combining a prepolymer, a curing agent and a white
pigment and then randomly dispersing cerium oxide nanoparticles
having a particle size of from about 370 nm to about 800 nm into
the cover material; and forming the cover about the core.
[0050] Meanwhile, the method of manufacturing a golf ball may also
comprise forming a core having an inner core layer and an outer
core layer, said outer core layer comprising an ordered array of
cerium oxide nanoparticles having a particle size of from about 370
nm to about 800 nm; and forming a cover about the core.
[0051] For any of the embodiments disclosed above and herein, the
cover, an outer core layer, an intermediate layer, an inner cover
layer or a coating may alternatively comprise either cerium oxide
nanoparticles or the substantially homogenous particulate in an
amount of from about 0.5 wt % to about 10 wt % of the layer/coating
formulation. In one embodiment, the layer/coating comprises about 1
wt % of cerium oxide nanoparticles or substantially homogenous
particulate. In another embodiment, the comprises about 1 wt %
cerium oxide nanoparticles or substantially homogenous particulate.
In yet another embodiment, the layer/coating comprises about 2 wt %
of cerium oxide nanoparticles or substantially homogenous
particulate. In still another embodiment, the layer/coating
comprises about 3 wt % of cerium oxide nanoparticles or
substantially homogenous particulate. In an alternative embodiment,
the layer/coating comprises about 4 wt % of cerium oxide
nanoparticles or substantially homogenous particulate. The
layer/coating may also comprise from about 5 wt % to about 10 wt %,
or from about 8 wt % to about 10 wt %, or from about 7 wt % to
about 10 wt %, or from about 9 wt % to about 10 wt %, or from about
3 wt % to about 7 wt % or even from about 0.5 wt % to about 3 wt %
of cerium oxide nanoparticles or substantially homogenous
particulate.
[0052] In any or all of the embodiments disclosed herein, the
cerium oxide nanoparticles may alternatively have a particle size
of from about 370 nm to about 750 nm, or from about 400 nm to about
800 nm, or from about 400 nm to about 750 nm, or from about 380 nm
to about 750 nm, or from about 400 nm to about 700 nm, or from
about 625 nm to about 740 nm, or from about 590 nm to about 625 nm,
or from about 565 nm to about 590 nm, or from about 520 nm to about
565 nm, or from about 500 nm to about 520 nm, or from about 435 nm
to about 500 nm, or from about 380 nm to about 435 nm.
[0053] In one embodiment, the vapor barrier composition has a
moisture vapor transmission rate of from about 0.45
gramsmm/m.sup.2day to about 1.5 gramsmm/m.sup.2day. In another
embodiment, the vapor barrier composition has a moisture vapor
transmission rate of about 0.95 gramsmm/m.sup.2day or greater.
[0054] In general, the lower limit of Mooney viscosity of a
composition comprising cerium oxide nanoparticles as described
herein may be 30 or 35 or 40 or 45 or 50 or 55 or 60 or 70 or 75
and the upper limit may be 80 or 85 or 90 or 95 or 100 or 105 or
110 or 115 or 120 or 125 or 130.
[0055] In one embodiment, the overall golf ball has a compression
of from about 25 to about 110. In another embodiment, the overall
golf ball has a compression of from about 35 to about 100. In yet
another embodiment, the overall golf ball has a compression of from
about 45 to about 95. In still another embodiment, the compression
may be from about 55 to about 85, or from about 65 to about 75.
Meanwhile, the compression may also be from about 50 to about 110,
or from about 60 to about 100, or from about 70 to about 90, or
even from about 80 to about 110.
[0056] Generally, in golf balls of the invention, the overall golf
ball COR is at least about 0.780. In another embodiment, the
overall golf ball COR is at least about 0.788. In yet another
embodiment, the overall golf ball COR is at least about 0.791. In
still another embodiment, the overall golf ball COR is at least
about 0.794. Also, the overall golf ball COR may be at least about
0.797. The overall golf ball COR may even be at least about 0.800,
or at least about 0.803, or at least about 0.812.
[0057] Meanwhile, the inventive golf ball comprising cerium oxide
nanoparticles as disclosed and claimed herein is versatile in that
a wide range of Shore C and Shore D hardnesses may be chosen and
coordinated for each of the core, core layers, intermediate layers
and cover layers as known by thosed skilled in the golf ball art
for achieving desired feel and playing characteristics. In this
regard, cerium oxide nanoparticles will serve as filler in order to
increase the density or specific gravity of a substrate into which
they are mixed, whtehr it be an outer core layer, intermediate
layer, inner cover layer, outer cover, or in a coating.
DETAILED DESCRIPTION
[0058] The term "cerium oxide" (CeO.sub.2) as used herein shall
refer to any and all terms used interchangeably by those skilled in
the art to denote CeO.sub.2 including, for example, known as ceric
oxide, ceria, or cerium dioxide, being an oxide of the rare earth
metal cerium.
[0059] Herein, the phrase "substantially homogeneous particulate"
means formed totally and solely of separate cerium oxide
particles.
[0060] The term "randomly dispersed", as used herein, shall refer
to the cerium oxide nanoparticles being dispersed or distributed
within the thermoset or theromoplastic cover composition
irrespective and independently of the positioning or spacing of
other components, elements, particles or any arrays incorporated
within the cover composition.
[0061] The term "ordered array" as used herein shall refer to a
deliberate pattern, spacing positioning or distribution of the
cerium oxide nanoparticles within the thermoset or theromoplastic
composition.
[0062] The cores in golf balls manufactured by the process 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 at least a base rubber, free-radical
initiator agent, cross-linking co-agent, and fillers. Golf balls
having various constructions may be made in accordance with this
invention. For example, golf balls having three-piece, four-piece,
and five-piece constructions with dual or three-layered cores and
cover materials may be made The term, "layer" as used herein means
generally any spherical portion of the golf ball. More
particularly, in one version, a three-piece golf ball comprising a
core and a "dual-cover" is made. In another version, a four-piece
golf ball comprising a dual-core and "dual-cover" is made. The
dual-core includes an inner core (center) and surrounding outer
core layer. The dual-cover includes inner cover and outer cover
layers. In yet another construction, a five-piece golf ball having
a dual-core, intermediate layer, and dual-cover is made. In still
another embodiment, a four piece golf ball comprises a core and a
three layer cover.
[0063] 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 diameter and thickness of the different
layers along with properties such as hardness and compression may
vary depending upon the construction and desired playing
performance properties of the golf ball and as specified
herein.
[0064] The inner core of the golf ball may comprise a polybutadiene
rubber material. In one embodiment, the ball contains a single core
formed of the polybutadiene rubber composition. In a second
embodiment, the ball contains a dual-core comprising an inner core
(center) and surrounding outer core layer. In yet another version,
the golf ball contains a multi-layered core comprising an inner
core, intermediate core layer, and outer core layer.
[0065] In general, polybutadiene is a homopolymer of 1,3-butadiene.
The double bonds in the 1,3-butadiene monomer are attacked by
catalysts to grow the polymer chain and form a polybutadiene
polymer having a desired molecular weight. Any suitable catalyst
may be used to synthesize the polybutadiene rubber depending upon
the desired properties. Normally, a transition metal complex (for
example, neodymium, nickel, or cobalt) or an alkyl metal such as
alkyllithium is used as a catalyst. Other catalysts include, but
are not limited to, aluminum, boron, lithium, titanium, and
combinations thereof. The catalysts produce polybutadiene rubbers
having different chemical structures. In a cis-bond configuration,
the main internal polymer chain of the polybutadiene appears on the
same side of the carbon-carbon double bond contained in the
polybutadiene. In a trans-bond configuration, the main internal
polymer chain is on opposite sides of the internal carbon-carbon
double bond in the polybutadiene. The polybutadiene rubber can have
various combinations of cis- and trans-bond structures. A preferred
polybutadiene rubber has a 1,4 cis-bond content of at least 40%,
preferably greater than 80%, and more preferably greater than 90%.
In general, polybutadiene rubbers having a high 1,4 cis-bond
content have high tensile strength. The polybutadiene rubber may
have a relatively high or low Mooney viscosity.
[0066] Examples of commercially available polybutadiene rubbers
that can be used in accordance with this invention, include, but
are not limited to, BR 01 and BR 1220, available from BST
Elastomers of Bangkok, Thailand; SE BR 1220LA and SE BR1203,
available from DOW Chemical Co of Midland, Michigan; BUDENE 1207,
1207s, 1208, and 1280 available from Goodyear, Inc of Akron, Ohio;
BR 01, 51 and 730, available from Japan Synthetic Rubber (JSR) of
Tokyo, Japan; BUNA CB 21, CB 22, CB 23, CB 24, CB 25, CB 29 MES, CB
60, CB Nd 60, CB 55 NF, CB 70 B, CB KA 8967, and CB 1221, available
from Lanxess Corp. of Pittsburgh. Pennsylvania; BR1208, available
from LG Chemical of Seoul, South Korea; UBEPOL BR130B, BR150,
BR150B, BR150L, BR230, BR360L, BR710, and VCR617, available from
UBE Industries, Ltd. of Tokyo, Japan; EUROPRENE NEOCIS BR 60,
INTENE 60 AF and P30AF, and EUROPRENE BR HV80, available from
Polimeri Europa of Rome, Italy; AFDENE 50 and NEODENE BR40, BR45,
BR50 and BR60, available from Karbochem (PTY) Ltd. of Bruma, South
Africa; KBR 01, NdBr 40, NdBR-45, NdBr 60, KBR 710S, KBR 710H, and
KBR 750, available from Kumho Petrochemical Co., Ltd. Of Seoul,
South Korea; DIENE 55NF, 70AC, and 320 AC, available from Firestone
Polymers of Akron, Ohio; and PBR-Nd Group II and Group III,
available from Nizhnekamskneftekhim, Inc. of Nizhnekamsk,
Tartarstan Republic.
[0067] Suitable polybutadiene rubbers for blending with the base
rubber may include BUNA.RTM. CB22, BUNA.RTM. CB23 and BUNA.RTM.
CB24, BUNA .RTM. 1203G1, 1220, 1221, and BUNA .RTM. CBNd-40,
commercially available from LANXESS Corporation; BSTE 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; Budene 1207, 1208 and 1280,
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.
Neodene 40, 45, and 60, commercially available from Karbochem.
[0068] The base rubber may further include polyisoprene rubber,
natural rubber, ethylene-propylene rubber, ethylene-propylene diene
rubber, styrene-butadiene rubber, and combinations of two or more
thereof. 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 as part of the blend. Such
compositions will provide increased flexural modulus and toughness
thereby improving the golf ball's performance including its impact
durability. 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 compound 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 Cray Valley
Resource Innovations Inc. Other elastomers known in the art may
also be added, 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.
[0069] Thermoplastic elastomers (TPE) may also be used to modify
the properties of the core layers, or the uncured core layer stock
by blending with the uncured 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 embodiement, the TPV
has a thermoplastic as a continuous phase and a cross-linked rubber
particulate as a dispersed (or discontinuous) phase. In another
emobodiment, the TPV has a cross-linked phase as a continuous phase
and a thermoplasttic as a dispersed (or discontinuous) phase to
provide reduced loss in elasticity in order to improve the
resiliency of the golf ball.
[0070] 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 bonds in the polybutadiene to trans 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.
[0071] 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.
[0072] 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.
[0073] A wide variety of thermoplastic or thermosetting materials
can be employed in forming the core, cover layers, or both. These
materials include for example, olefin-based copolymer ionomer
resins (for example, Surlyn.RTM. ionomer resins and DuPont.RTM. HPF
1000 and HPF 2000, as well as blends of
Surlyn.RTM.7940/Surlyn.RTM.8940 or Surlyn.RTM.8150/Surlyn.RTM.9150
commercially available from E. I. du Pont de Nemours and Company;
Iotek.RTM. ionomers, commercially available from ExxonMobil
Chemical Company; Amplify.RTM. IO 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.
[0074] In fact, any of the core, intermediate layer and/or cover
layers may include the following materials:
[0075] (1) Polyurethanes, such as those prepared from polyols and
diisocyanates or polyisocyanates and/or their prepolymers;
[0076] (2) Polyureas; and
[0077] (3) Polyurethane-urea hybrids, blends or copolymers
comprising urethane and urea segments.
[0078] Polyurethanes and polyureas may constitute either thermoset
or thermoplastic compositions, depending on the type of
crosslinking bond that is created during formation of the
composition. When a polyurethane or polyurea prepolymer is cross
linked with a polyfunctional curing agent, covalent bonding occurs,
resulting in a thermoset composition. In contrast, polyurethanes
and polyureas will be thermoplastic where the crosslinking is due,
for example, to hydrogen bonding, resulting in weaker bonds which
may be broken upon heating the composition. This distinction
explains why thermoset materials generally may not be reclycled or
reformed into a different shape by heating (at least not easily),
whereas thermoplastic materials may so be. The process for
manufacturing a golf ball according to the invention is
particularly well-suited for forming golf balls having a
combination of a very thin, thermoplastic outer cover and a
thermoset inner cover having a thickness greater than that of the
outer cover layer, providing both COR stability and
playability.
[0079] 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.
[0080] 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
[0081] (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 team MDI includes
4,4'-diphenylmethane diisocyanate, polymeric MDI,
carbodiimide-modified liquid MDI, and mixtures thereof.
Additionally, the prepolymers synthesized from these diisocyanates
may be "low free monomer," understood by one of ordinary skill in
the art to have lower levels of "free" isocyanate monomers,
typically less than about 0.1% free isocyanate. Examples of "low
free monomer" prepolymers include, but are not limited to Low Free
Monomer MDI prepolymers, Low Free Monomer TDI prepolymers, and Low
Free Monomer PPDI prepolymers.
[0082] 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.
[0083] 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.
[0084] 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.
[0085] 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.
[0086] 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. 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.
[0087] 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
include ethylene glycol; diethylene glycol; polyethylene glycol;
propylene glycol;
[0088] 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-temiinated 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.
[0089] Both the hydroxy-terminated and amine curatives can include
one or more saturated, unsaturated, aromatic, and cyclic groups.
Additionally, the hydroxy-temlinated 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.
[0090] In one embodiment of the present invention, saturated
polyurethanes are used to form one or more of the cover layers.
[0091] Additionally, polyurethane can be replaced with or blended
with a polyurea material. Polyureas are distinctly different from
polyurethane compositions, giving better shear resisitance.
[0092] 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.
[0093] The polyurea composition can be formed by crosslinking a
polyurea prepolymer with a single curing agent or a blend of curing
agents. 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
[0094] 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; triethylene tetramine;
tetraethylene pentamine; propylene diamine; 1,3-diaminopropane;
dimethylamino propylamine; diethylamino propylamine; dipropylene
triamine; imido-bis-propylamine; monoethanolamine, diethanolamine;
3,5-diethyltoluene-2,4-diamine; 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.
[0095] 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.
Alternatively, other suitable polymers include partially or fully
neutralized ionomer, metallocene, or other single-site catalyzed
polymer, polyester, polyimide, 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.
[0096] Intermediate layers and/or cover layers may also be formed
from ionomeric polymers or ionomer blends such as Surlyn 7940/8940
or Surlyn 8150/9150 or from highly-neutralized ionomers (HNP).
[0097] In one 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% with a cation source. Suitable cation sources include
metal cations and salts thereof, organic amine compounds, ammonium,
and combinations thereof. The HNP's can be also be blended with a
second polymer component, which, if containing an acid group(s)
such as organic acids, or more preferably fatty acids, may be
neutralized in a conventional manner, with a suitable cation
source. 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.
[0098] 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 sufficient amount of
metal base to achieve the desired neutralization level. 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.
[0099] 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.
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.
[0100] 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, the ionomer can be
neutralized, without losing processability, to a level much greater
than for a metal cation alone. Preferably, the acid moieties are
neutralized greater than about 80%, preferably from 90-100%, most
preferably 100% without losing processability. This is 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%).
[0101] The organic acids may be 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).
[0102] The ionomers 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.
[0103] The golf ball may also 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, and a balance of ball performance.
[0104] Blowing/foaming agents may also be particularly compatible
with the golf ball produced by the process of the invention,
including, for example those disclosed in U.S. Pat. No. 7,708,654.
Typical physical foaming/blowing agents include volatile liquids
such as freons (CFCs), other halogenated hydrocarbons, water,
aliphatic hydrocarbons, gases, and solid blowing agents, i.e.,
compounds that liberate gas as a result of desorption of gas.
Preferably, the blowing agent includes an adsorbent. Typical
adsorbents include, for example, activated carbon, calcium
carbonate, diatomaceous earth, and silicates saturated with carbon
dioxide.
[0105] Chemical foaming/blowing agents may be incorporated.
Chemical blowing agents may be inorganic, such as ammonium
carbonate and carbonates of alkalai metals, or may be organic, such
as azo and diazo compounds, such as nitrogen-based azo compounds.
Suitable azo compounds include, but are not limited to,
2,2'-azobis(2-cyanobutane), 2,2'-azobis(methylbutyronitrile),
azodicarbonamide, p,p'-oxybis(benzene sulfonyl hydrazide),
p-toluene sulfonyl semicarbazide, p-toluene sulfonyl hydrazide.
Other blowing agents include any of the Celogens.RTM., sold by
Crompton Chemical Corporation, and nitroso compounds,
sulfonylhydrazides, azides of organic acids and their analogs,
triazines, tri- and tetrazole derivatives, sulfonyl semicarbazides,
urea derivatives, guanidine derivatives, and esters such as
alkoxyboroxines. Other possible blowing agents include agents that
liberate gasses as a result of chemical interaction between
components such as mixtures of acids and metals, mixtures of
organic acids and inorganic carbonates, mixtures of nitriles and
ammonium salts, and the hydrolytic decomposition of urea.
[0106] Alternatively, low specific gravity can be achieved by
incorporating low density fillers or agents such as hollow fillers
or microspheres in the polymeric matrix, where the cured
composition has the preferred specific gravity. Moreover, the
polymeric matrix can be foamed to decrease its specific gravity,
microballoons, or other low density fillers as described in U.S.
Pat. No. 6,692,380 ("'380 Patent"). The '380 patent is incorporated
by reference in its entirety.
[0107] Blends including non-ionomeric and olefin-based ionomeric
polymers may also be incorporated to form a 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. Also, in one embodiment
of the invention, processability of the golf ball of the invention
may even be enhanced by incorporating in the core a
metallocene-catalyzed polybutadiene.
[0108] 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 moisture barrier 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.
[0109] In one embodiment, the overall golf ball produced by the
process of the invention has a compression of from about 25 to
about 110. In another embodiment, the overall golf ball has a
compression of from about 35 to about 100. In yet another
embodiment, the overall golf ball has a compression of from about
45 to about 95. In still another embodiment, the compression may be
from about 55 to about 85, or from about 65 to about 75. Meanwhile,
the compression may also be from about 50 to about 110, or from
about 60 to about 100, or from about 70 to about 90, or even from
about 80 to about 110.
[0110] Generally, in golf balls produced by the process of the
invention, the overall golf ball COR is at least about 0.780. In
another embodiment, the overall golf ball COR is at least about
0.788. In yet another embodiment, the overall golf ball COR is at
least about 0.791. In still another embodiment, the overall golf
ball COR is at least about 0.794. Also, the overall golf ball COR
may be at least about 0.797. The overall golf ball COR may even be
at least about 0.800, or at least about 0.803, or at least about
0.812.
[0111] The core, intermediate layer(s) and/or cover layers 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,
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.
[0112] A golf ball according to the invention may therefore achieve
various hardness gradients therein. For example, the golf ball made
by the process of the invention may be incorporate a single-solid
core having a "positive" hardness gradient (that is, the outer
surface of the core is harder than its geometric center.) In a
second embodiment, the core may be a dual-core comprising an inner
core and a surrounding outer core layer. The inner core has a
"positive" hardness gradient and the outer core layer has a
"negative" hardness gradient (that is, the outer surface of the
outer core layer is softer than the inner surface of the outer core
layer.) Other embodiments of golf balls having various combinations
of positive, negative, and zero hardness gradients may be made in
accordance with this invention. For example, the inner core may
have a positive hardness gradient and the outer core layer also may
have a positive hardness gradient. In another example, the inner
core may have a positive hardness gradient and the outer core layer
may have a "zero" hardness gradient. (That is, the hardness values
of the outer surface of the outer core layer and the inner surface
of the outer core layer are substantially the same.) Particularly,
the term, "zero hardness gradient" as used herein, means a surface
to center Shore C hardness gradient of less than 8, preferably less
than 5 and most preferably less than 3 and may have a value of zero
or negative 1 to negative 25. The term, "negative hardness
gradient" as used herein, means a surface to center Shore C
hardness gradient of less than zero. The terms, zero hardness
gradient and negative hardness gradient, may be used herein
interchangeably to refer to hardness gradients of negative 1 to
negative 25. The term, "positive hardness gradient" as used herein,
means a surface to center Shore C hardness gradient of 8 or
greater, preferably 10 or greater, and most preferably 20 or
greater. By the term, "steep positive hardness gradient" as used
herein, it is meant surface to center Shore C hardness gradient of
20 or greater, more preferably 25 or greater, and most preferably
30 or greater. Methods for measuring the hardness of the inner core
and surrounding layers and determining the hardness gradients are
discussed in further detail below.
[0113] The center hardness of a core is obtained according to the
following procedure. 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 is 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` surface is ground to a smooth, flat surface,
revealing the geometric center of the core, which can be verified
by measuring the height from 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. 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 according to ASTM D-2240.
Additional hardness measurements at any distance from the center of
the core can then be made by drawing a line radially outward from
the center mark, and measuring the hardness at any given distance
along the line, typically in 2 mm increments from the center. The
hardness at a particular distance from the center should be
measured along at least two, preferably four, radial arms located
180.degree. apart, or 90.degree. apart, respectively, and then
averaged. All hardness measurements performed on a 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, and thus also parallel to the properly aligned foot of the
durometer.
[0114] The outer surface hardness of a golf ball layer is measured
on the actual outer surface of the layer and is obtained from the
average of a number of measurements taken from opposing
hemispheres, 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, care must be taken to
ensure that the golf ball or golf ball subassembly 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 may be used for the hardness measurements. The
digital durometer is attached to, and its foot made parallel to,
the base of an automatic stand. The weight on the durometer and
attack rate conform to ASTM D-2240. In certain embodiments, a point
or plurality of points measured along the "positive" or "negative"
gradients may be above or below a line fit through the gradient and
its outermost and innermost hardness values. In an alternative
preferred embodiment, the hardest point along a particular steep
"positive" or "negative" gradient may be higher than the value at
the innermost portion of the inner core (the geometric center) or
outer core layer (the inner surface)--as long as the outermost
point (i.e., the outer surface of the inner core) is greater than
(for "positive") or lower than (for "negative") the innermost point
(i.e., the geometric center of the inner core or the inner surface
of the outer core layer), such that the "positive" and "negative"
gradients remain intact.
[0115] As discussed above, the direction of the hardness gradient
of a golf ball layer is defined by the difference in hardness
measurements taken at the outer and inner surfaces of a particular
layer. The center hardness of an inner core and hardness of the
outer surface of an inner core in a single-core ball or outer core
layer are readily determined according to the test procedures
provided above. The outer surface of the inner core layer (or other
optional intermediate core layers) in a dual-core ball are also
readily determined according to the procedures given herein for
measuring the outer surface hardness of a golf ball layer, if the
measurement is made prior to surrounding the layer with an
additional core layer. Once an additional core layer surrounds a
layer of interest, the hardness of the inner and outer surfaces of
any inner or intermediate layers can be difficult to determine.
Therefore, for purposes of the present invention, when the hardness
of the inner or outer surface of a core layer is needed after the
inner layer has been surrounded with another core layer, the test
procedure described above for measuring a point located 1 mm from
an interface is used.
[0116] Also, it should be understood that there is a fundamental
difference between "material hardness" and "hardness as measured
directly on a golf ball." For purposes of the present invention,
material hardness is measured according to ASTM D2240 and generally
involves measuring the hardness of a flat "slab" or "button" formed
of the material. Surface hardness as measured directly on a golf
ball (or other spherical surface) typically results in a different
hardness value. The difference in "surface hardness" and "material
hardness" values is due to several factors including, but not
limited to, ball construction (that is, core type, number of cores
and/or cover layers, and the like); ball (or sphere) diameter; and
the material composition of adjacent layers, and thickness of the
various layers. It also should be understood that the two
measurement techniques are not linearly related and, therefore, one
hardness value cannot easily be correlated to the other. Shore C
hardness was measured according to the test methods D-2240.
[0117] 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 or PGA
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 1.680 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. The approximate
relationship that exists between Atti or PGA compression and Riehle
compression can be expressed as: (Atti or PGA
compression)=(160-Riehle
[0118] Compression). Thus, a Riehle compression of 100 would be the
same as an Atti compression of 60.
[0119] 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.
[0120] 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.
[0121] 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 center has a higher density or
specific gravity than the outer layers, 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 golf ball of the invention may be
from about 0.410 oz-in.sup.2 to about 0.470 oz-in.sup.2. The moment
of inertia for a one piece ball that is 1.62 ounces and 1.68 inches
in diameter may be approximately 0.4572 oz-in.sup.2, which is the
baseline moment of inertia value.
[0122] Accordingly, by varying the materials and the density of the
regions of each core or cover 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.t to about 0.460 oz-in.sup.2.
[0123] Cerium oxide (CeO.sub.2) particles having sizes in the range
of the visible spectrum (about 370 nm-about 800 nm) reflect or
scatter light and therefore provide opacity sufficient to cover the
underlying golf ball core and create a white appearance to the
human eye. Meanwhile unlike TiO.sub.2, cerium oxide beneficially
provides UV resistance without exhibiting an undesirable
"photocatalytic effect".
[0124] A golf ball cover comprising cerium oxide nanoparticles,
having a particle size in the range of the wavelength of visible
light, and being randomly incorporated into the cover, retains a
whiter appearance over time as compared with a TiO.sub.2-comprising
cover as demonstrated in Table I below. In this regard, the
following experiment was performed to monitor .DELTA.Yl and
.DELTA.b* for four inventive golf ball covers versus four
comparative golf ball covers.
[0125] Eight golf ball covers, labeled I, IA, II, IIA, III, IIIA,
IV, IVA, respectively, were formulated and then monitored and
evaluated for comparative UV degradation, .DELTA.Yl and .DELTA.b*
being measured after 5 days and then again after 8 days. All eight
golf ball covers were prepared by combining in a static mixer
prepolymer X from a holding tank A with the components from holding
tank B, namely curing agent Y, white dispersion Z and either
CeO.sub.2 or TiO.sub.2 as specified in Table I. For each of the
eight cover formulations, an identical mixing temperature was
chosen in the range from about 60.degree. F. to about 180.degree.
F. (room temperature or under heat to speed up the reaction or
reduce the viscosity of the mixture as desired). Cover I is
identical to cover IA except that cover I comprises 1% CeO.sub.2
and cover IA instead comprises 1% TiO.sub.2 in addition to any
TiO.sub.2 contained in white dispersion Z. Cover II is identical to
cover IIA except that cover II comprises 2% CeO.sub.2 and cover IIA
instead comprises 2% TiO.sub.2 in addition to any TiO.sub.2
contained in white dispersion Z. Cover III is identical to cover
IIIA except that cover III comprises 3% CeO.sub.2 and cover IIIA
instead comprises 3% TiO.sub.2 in addition to any TiO.sub.2
contained in white dispersion Z. Cover IV is identical to cover IVA
except that cover IV comprises 4% CeO.sub.2 and cover IVA instead
comprises 4% TiO.sub.2 in addition to any TiO.sub.2 contained in
white dispersion Z.
[0126] The results are recorded in Table I below:
TABLE-US-00001 TABLE I Cover Formulation* I IA II IIA III IIIA IV
IVA 1% CeO.sub.2 1% TiO.sub.2 2% CeO.sub.2 2% TiO.sub.2 3%
CeO.sub.2 3% TiO.sub.2 4% CeO.sub.2 4% TiO.sub.2 HCC 19584 4.5%
4.5% 3.5% 3.5% 2.5% 2.5% 1.5% 1.5% Initial Yl -1.2 -4.22 0.94 -1.30
1.43 2.66 8.12 5.35 Initial b -3.66 -5.35 -2.56 -3.83 0.67 -2.11
1.28 -0.42 Day 5 .DELTA.Yl 10.5 14.8 10.9 16.5 10.5 17.7 9.97 20.6
.DELTA.b 6.25 8.65 6.60 9.87 6.34 12.5 6.00 12.8 Day 8 .DELTA.Yl
12.2 17.7 12.1 19.4 12.6 21.5 11.7 25.5 .DELTA.b 7.22 10.3 7.13
11.5 7.54 13.0 6.99 15.8 *The cover was formulated as follows: 1.0
equivalent of RAP 8.6 prepolymer; 0.95 equivalents of Ethacure
100LC; HCC 19584 white dispersion; and cerium oxide. RAP is a
reaction product of HDI dimer with a silicone-amine adduct from
Engineered Polymers. Ethacure 100LC is an amine curing agent from
Albermarie. HCC 19584 is a white dispersion from The PolyOne
Corporation. The cerium oxide is Polishing Opaline SM2 from Rhodia,
having particle sizes in the range of from about 0.4.mu.-about
0.6.mu. (about 400 nm-about 600 nm).
[0127] As Table I above reveals, comparing covers I and IA, after 5
days, both .DELTA.Yl and .DELTA.b are favorably lower for cover
composition I than cover composition IA--by 4.3 and 2.4,
respectively. And after 8 days, .DELTA.Yl and .DELTA.b are both
favorably lower for cover composition I than cover composition
IA--by 5.5 and 3.08, respectively. Comparing covers II and IIA,
after 5 days, .DELTA.Yl and .DELTA.b are also both favorably lower
for cover composition II than cover composition IIA--by 5.6 and
3.27, respectively. And after 8 days, .DELTA.Yl and .alpha.b are
both favorably lower for cover composition II than cover
composition IIA--by 7.3 and 4.37, respectively. Comparing covers
III and IIIA, after 5 days, .DELTA.Yl and .DELTA.b are also both
favorably lower for cover composition III than cover composition
IIIA--by 7.2 and 6.16, respectively. And after 8 days, .DELTA.Yl
and .DELTA.b are both favorably lower for cover composition III
than cover composition IIIA--by 8.9 and 5.46, respectively.
Comparing covers IV and IVA, after 5 days, .DELTA.Yl and .DELTA.b
are also both favorably lower for cover composition IV than cover
composition IVA--by 10.63 and 6.8, respectively. And after 8 days,
.DELTA.Yl and .DELTA.b are both favorably lower for cover
composition IV than cover composition IVA--by 13.8 and 8.81,
respectively. Accordingly, the results above demonstrate that a
golf ball comprising a cover incorporating CeO.sub.2 having a
particle size within the wavelength of visible light provides
substantially reduced yellowing/UV degradation over a golf ball
cover without CeO.sub.2 and further, over a golf ball cover
incorporating TiO.sub.2 instead of CeO.sub.2.
[0128] All of the golf ball covers in each of the examples above do
comprise some TiO.sub.2 in that the colorant of dispersion Z
comprises a long chain triol and TiO.sub.2. However, it is
envisioned that a golf ball of the invention may alternatively have
a cover incorporating CeO.sub.2 and no TiO.sub.2. This is because
the reduced yellowing imparted to an inventive golf ball having a
cover incorporating CeO.sub.2 in at least the amounts and weight
percents disclosed herein occurs independently of the presence or
placement of TiO.sub.2 in the golf ball cover.
[0129] Also, any other procedure known in the art for combining and
mixing a prepolymer, curing agent and colorant may be used to form
a golf ball cover of the invention in lieu of the method discussed
above. Furthermore, the CeO.sub.2 may be added into the formulation
either along with the curative and a colorant from holding tank A
or alternatively may be included as part of the prepolymer mix from
holding tank A or even mixed into the static mixer from a
completely separate holding tank C.
[0130] The compositions for golf ball components as disclosed
herein may also be used in sporting equipment in general.
Specifically, the compositions may be applied in various game
balls, golf club shafts, golf club head inserts, golf shoe
components, and the like. Additionally, the compositions for golf
ball components as disclosed herein may also be used to reduce any
UV degradation in golf balls/sporting equipment regardless of
color.
[0131] All patents and patent applications cited in the foregoing
text are expressly incorporated herein by reference in their
entirety.
[0132] 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.
[0133] 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.
[0134] 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.
[0135] 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.
[0136] 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 328 to 392, although the golf ball of
the invention may have any number of dimples or dimples
configurations as presently known in the art. The dimples may
comprise any width, depth, and edge angle and patterns which
satisfy the relationships defined between cover layers as disclosed
herein. The parting line configuration of said pattern may be
either a straight line or a staggered wave parting line (SWPL). In
one embodiment, the golf bal has 328, 330, 332, or 392 dimples,
comprises 5 to 7 dimples sizes, and the parting line is a SWPL.
[0137] In any of these embodiments the single-layer core may be
replaced with a two or more layer core wherein.
[0138] 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.
[0139] 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.
* * * * *