U.S. patent application number 12/047982 was filed with the patent office on 2008-07-03 for multi-layer golf ball.
Invention is credited to Herbert C. Boehm, Derek A. Ladd, William E. Morgan, Michael J. Sullivan.
Application Number | 20080161130 12/047982 |
Document ID | / |
Family ID | 39584810 |
Filed Date | 2008-07-03 |
United States Patent
Application |
20080161130 |
Kind Code |
A1 |
Sullivan; Michael J. ; et
al. |
July 3, 2008 |
Multi-layer golf ball
Abstract
Golf balls consisting of a single-layer core and a two-layer
cover are disclosed. The surface hardness of the core layer is
greater than the material hardness of the inner cover layer, and is
preferably 80 Shore C or greater.
Inventors: |
Sullivan; Michael J.;
(Barrington, RI) ; Ladd; Derek A.; (Acushnet,
MA) ; Morgan; William E.; (Barrington, RI) ;
Boehm; Herbert C.; (Norwell, MA) |
Correspondence
Address: |
ACUSHNET COMPANY
333 BRIDGE STREET, P. O. BOX 965
FAIRHAVEN
MA
02719
US
|
Family ID: |
39584810 |
Appl. No.: |
12/047982 |
Filed: |
March 13, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11767070 |
Jun 22, 2007 |
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12047982 |
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10773906 |
Feb 6, 2004 |
7255656 |
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11767070 |
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10341574 |
Jan 13, 2003 |
6852044 |
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10773906 |
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10002641 |
Nov 28, 2001 |
6547677 |
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10341574 |
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Current U.S.
Class: |
473/374 |
Current CPC
Class: |
A63B 37/0066 20130101;
A63B 37/0062 20130101; A63B 37/0003 20130101 |
Class at
Publication: |
473/374 |
International
Class: |
A63B 37/00 20060101
A63B037/00 |
Claims
1. A golf ball consisting of: a solid, single-layer core formed
from a rubber composition and having a diameter of from 1.51 inches
to 1.59 inches and a surface hardness of 80 Shore C or greater; an
inner cover layer formed from a thermoplastic composition and
having a material hardness less than the surface hardness of the
core; and an outer cover layer formed from a polyurethane or
polyurea composition.
2. The golf ball of claim 1, wherein the outer cover layer has a
material hardness less than the surface hardness of the core.
3. The golf ball of claim 1, wherein the diameter of the core is
from 1.53 inches to 1.55 inches.
4. The golf ball of claim 1, wherein the surface hardness of the
core is greater than 80 Shore C.
5. The golf ball of claim 1, wherein the surface hardness of the
core is greater than 85 Shore C.
6. The golf ball of claim 1, wherein the surface hardness of the
core is 87 Shore C or greater.
7. The golf ball of claim 1, wherein the surface hardness of the
core is 90 Shore C or greater.
8. The golf ball of claim 1, wherein the core has a compression of
from 50 to 90.
9. The golf ball of claim 1, wherein the core has a compression of
from 60 to 80.
10. The golf ball of claim 1, wherein the core has a center
hardness of 80 Shore C or less.
11. The golf ball of claim 1, wherein the core has a center
hardness of 70 Shore C or less.
12. The golf ball of claim 1, wherein the core has a center
hardness of 60 Shore C or less.
13. The golf ball of claim 1, wherein the material hardness of the
inner cover layer is from 80 Shore C to 90 Shore C.
14. The golf ball of claim 1, wherein the material hardness of the
inner cover layer is from 82 Shore C to 86 Shore C.
15. The golf ball of claim 1, wherein the inner cover layer
composition is an ionomeric blend.
16. The golf ball of claim 1, wherein the inner cover layer
composition comprises an ionomer and a maleic anhydride-grafted
polymer.
17. The golf ball of claim 1, wherein the outer cover layer
composition is a thermosetting polyurethane or polyurea.
18. The golf ball of claim 1, wherein the outer cover layer
composition is a thermoplastic polyurethane or polyurea.
19. The golf ball of claim 1, wherein the rubber composition
comprises a base rubber present in an amount of at least 85 wt %,
based on the total weight of rubber present in the composition.
20. The golf ball of claim 1, wherein the rubber composition
comprises a base rubber present in an amount of at least 95 wt %,
based on the total weight of rubber present in the composition.
21. The golf ball of claim 1, wherein the rubber composition
comprises a base rubber present in an amount of at least 99.9 wt %,
based on the total weight of rubber present in the composition.
22. A golf ball consisting of: a solid, single-layer core formed
from a rubber composition and having a diameter of from 1.51 inches
to 1.59 inches, a compression of from 60 to 80, a center hardness
of 70 Shore C or less, and a surface hardness of greater than 80
Shore C; an inner cover layer formed from a thermoplastic ionomeric
composition and having a material hardness less than the surface
hardness of the core; and an outer cover layer formed from a
polyurethane or polyurea composition.
23. The golf ball of claim 22, wherein the outer cover layer has a
material hardness less than the surface hardness of the core.
24. The golf ball of claim 22, wherein the diameter of the core is
from 1.53 inches to 1.55 inches.
25. The golf ball of claim 22, wherein the surface hardness of the
core is 85 Shore C or greater.
26. The golf ball of claim 22, wherein the material hardness of the
inner cover layer is from 80 Shore C to 90 Shore C.
27. The golf ball of claim 22, wherein the ionomeric composition
comprises a high acid ionomer.
28. A golf ball consisting of: a solid, single-layer core formed
from a rubber composition and having a diameter of from 1.53 inches
to 1.55 inches, a compression of from 60 to 80, a center hardness
of 65 Shore C or less, and a surface hardness of greater than 80
Shore C; an inner cover layer formed from a thermoplastic ionomeric
composition and having a material hardness less than the surface
hardness of the core; and an outer cover layer formed from a
polyurethane or polyurea composition.
29. The golf ball of claim 28, wherein the outer cover layer has a
material hardness less than the surface hardness of the core.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation-in-part of U.S. patent
application Ser. No. 11/767,070, filed Jun. 22, 2007, which is a
continuation-in-part of U.S. patent application Ser. No.
10/773,906, filed Feb. 6, 2004, now U.S. Pat. No. 7,255,656, which
is a continuation-in-part of U.S. patent application Ser. No.
10/341,574, filed Jan. 13, 2003, now U.S. Pat. No. 6,852,044, which
is a continuation-in-part of U.S. patent application Ser. No.
10/002,641, filed Nov. 28, 2001, now U.S. Pat. No. 6,547,677, the
entire disclosures of which are hereby incorporated herein by
reference.
FIELD OF THE INVENTION
[0002] The present invention generally relates to golf balls, and
more particularly to golf balls having single-layer cores
surrounded by two-layer covers, wherein the surface hardness of the
core is greater than the material hardness of the inner cover
layer.
BACKGROUND OF THE INVENTION
[0003] Numerous golf balls having a multilayer construction wherein
the core hardness and cover hardness have been variously improved
are disclosed in the prior art. For example, U.S. Pat. No.
6,987,159 to Iwami discloses a solid golf ball with a solid core
and a polyurethane cover, wherein the difference in Shore D
hardness between a center portion and a surface portion of the
solid core is at least 15, the polyurethane cover has a thickness
(t) of not more than 1.0 mm and is formed from a cured urethane
composition having a Shore D hardness (D) of from 35 to 60, and a
product of t and D ranges from 10 to 45.
[0004] U.S. Pat. No. 7,175,542 to Watanabe et al. discloses a
multi-piece solid golf ball composed of a multilayer core having at
least an inner core layer and an outer core layer, one or more
cover layers which enclose the core, and numerous dimples formed on
a surface of the cover layer. The golf ball is characterized in
that the following hardness conditions are satisfied: (1) (JIS-C
hardness of cover)--(JIS-C hardness at center of core).gtoreq.27,
(2) 23.ltoreq.(JIS-C hardness at surface of core)--(JIS-C hardness
at center of core).ltoreq.40, and (3) 0.50.ltoreq.[(deflection
amount of entire core)/(deflection amount of inner core
layer)].ltoreq.0.75.
[0005] U.S. Pat. No. 6,679,791 to Watanabe discloses a multi-piece
golf ball which includes a rubbery elastic core, a cover having a
plurality of dimples on the surface thereof, and at least one
intermediate layer between the core and the cover. The intermediate
layer is composed of a resin material which is harder than the
cover. The elastic core has a hardness which gradually increases
radially outward from the center to the surface thereof. The center
and surface of the elastic core have a hardness difference of at
least 18 JIS-C hardness units.
[0006] U.S. Pat. No. 5,782,707 to Yamagishi et al. discloses a
three-piece solid golf ball consisting of a solid core, an
intermediate layer, and a cover, wherein the hardness is measured
by a JIS-C scale hardness meter, the core center hardness is up to
75 degrees, the core surface hardness is up to 85 degrees, the core
surface hardness is higher than the core center hardness by 8 to 20
degrees, the intermediate layer hardness is higher than the core
surface hardness by at least 5 degrees, and the cover hardness is
lower than the intermediate layer hardness by at least 5
degrees.
[0007] Additional examples can be found, for example, in U.S. Pat.
Nos. 6,686,436 to Iwami, 6,786,836 to Higuchi et al., 7,153,224 to
Higuchi et al., and 7,226,367 to Higuchi et al.
[0008] The present invention provides a novel multilayer golf ball
construction which may provide one or more of the following
benefits: higher spin on full iron shots and superior overall ball
performance properties.
SUMMARY OF THE INVENTION
[0009] In one embodiment, the present invention is directed to a
golf ball consisting of a solid, single-layer core, an inner cover
layer, and an outer cover layer. The core is formed from a rubber
composition and has a diameter of from 1.51 inches to 1.59 inches
and a surface hardness of 80 Shore C or greater. The inner cover
layer is formed from a thermoplastic composition and has a material
hardness less than the surface hardness of the core. The outer
cover layer is formed from a polyurethane or polyurea
composition.
[0010] In another embodiment, the present invention is directed to
a golf ball consisting of a solid, single-layer core, an inner
cover layer, and an outer cover layer. The core is formed from a
rubber composition and has a diameter of from 1.51 inches to 1.59
inches, a compression of from 60 to 80, a center hardness of 70
Shore C or less, and a surface hardness of greater than 80 Shore C.
The inner cover layer is formed from a thermoplastic ionomeric
composition and has a material hardness less than the surface
hardness of the core. The outer cover layer is formed from a
polyurethane or polyurea composition.
DETAILED DESCRIPTION
[0011] A golf ball having a solid, single-layer core and a
two-layer cover enclosing the core is disclosed. The core generally
has a diameter within a range having a lower limit of 1.40 or 1.45
or 1.50 or 1.51 or 1.53 inches and an upper limit of 1.55 or 1.59
or 1.60 or 1.62 or 1.66 inches, and preferably has a diameter
within a range having a lower limit of 1.51 or 1.53 inches and an
upper range of 1.55 or 1.59 inches. In a particularly preferred
embodiment, the core has a diameter of about 1.53 inches.
[0012] The core preferably has a center hardness of 70 Shore C or
less, or 65 Shore C or less; or a center hardness within a range
having a lower limit of 30 or 40 or 45 Shore C and an upper limit
of 70 or 75 or 80 Shore C; or a center hardness of about 60 Shore
C. The surface hardness of the core is preferably greater than 70
Shore C, or 75 Shore C or greater, or 80 Shore C or greater, or
greater than 80 Shore C, or 85 Shore C or greater, or greater than
85 Shore C, or 87 Shore C or greater, or 90 Shore C or greater. In
a particular embodiment, the surface hardness of the core is
greater than or equal to the center hardness of the core. In
another particular embodiment, the core has a positive hardness
gradient wherein the surface hardness of the core is at least 10
Shore C units greater than the center hardness of the core. In yet
another particular embodiment, the core has a positive hardness
gradient wherein the surface hardness of the core is at least 20
Shore C units greater than the center hardness of the core.
[0013] The surface hardness of a core is obtained from the average
of a number of measurements taken from opposing hemispheres of a
core, taking care to avoid making measurements on the parting line
of the core or on surface defects, such as holes or protrusions.
Hardness measurements are made pursuant to ASTM D-2240 "Indentation
Hardness of Rubber and Plastic by Means of a Durometer." Because of
the curved surface of a core, care must be taken to insure that the
core is centered under the durometer indentor before a surface
hardness reading is obtained. A calibrated, digital durometer,
capable of reading to 0.1 hardness units is used for all hardness
measurements and is set to take hardness readings at 1 second after
the maximum reading is obtained. The digital durometer must be
attached to, and its foot made parallel to, the base of an
automatic stand, such that the weight on the durometer and attack
rate conform to ASTM D-2240.
[0014] The center hardness of the 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, 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 of the bottom of the holder to the exposed
surface of the core, making sure that exactly half of the original
height of the core, as measured above, has been removed to within
.+-.0.004 inches. 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.
[0015] The core is preferably formed from a rubber composition or
from a highly resilient thermoplastic polymer such as a highly
neutralized polymer ("HNP") composition. Particularly suitable
thermoplastic polymers include Surlyn.RTM. ionomers, Hytrel.RTM.
thermoplastic polyester elastomers, and ionomeric materials sold
under the trade names DuPont.RTM. HPF 1000 and DuPont.RTM. HPF
2000, all of which are commercially available from E. I. du Pont de
Nemours and Company; Iotek.RTM. ionomers, commercially available
from ExxonMobil Chemical Company; and Pebax.RTM. thermoplastic
polyether block amides, commercially available from Arkema Inc.
[0016] Suitable HNP compositions for use in forming the core
comprise an HNP and optionally additives, fillers, and/or melt flow
modifiers. Suitable HNPs are salts of homopolymers and copolymers
of .alpha.,.beta.-ethylenically unsaturated mono- or dicarboxylic
acids, and combinations thereof, optionally including a softening
monomer. The acid polymer is neutralized to 70% or higher,
including up to 100%, with a suitable cation source. Suitable
additives and fillers include, for example, blowing and foaming
agents, optical brighteners, coloring agents, fluorescent agents,
whitening agents, UV absorbers, light stabilizers, defoaming
agents, processing aids, mica, talc, nanofillers, antioxidants,
stabilizers, softening agents, fragrance components, plasticizers,
impact modifiers, acid copolymer wax, surfactants; inorganic
fillers, such as zinc oxide, titanium dioxide, tin oxide, calcium
oxide, magnesium oxide, barium sulfate, zinc sulfate, calcium
carbonate, zinc carbonate, barium carbonate, mica, talc, clay,
silica, lead silicate, and the like; high specific gravity metal
powder fillers, such as tungsten powder, molybdenum powder, and the
like; regrind, i.e., core material that is ground and recycled; and
nano-fillers. Suitable melt flow modifiers include, for example,
fatty acids and salts thereof, polyamides, polyesters,
polyacrylates, polyurethanes, polyethers, polyureas, polyhydric
alcohols, and combinations thereof. Suitable HNP compositions also
include blends of HNPs with partially neutralized ionomers as
disclosed, for example, in U.S. Patent Application Publication No.
2006/0128904, the entire disclosure of which is hereby incorporated
herein by reference, and blends of HNPs with additional
thermoplastic and thermoset materials, including, but not limited
to, ionomers, acid copolymers, engineering thermoplastics, fatty
acid/salt-based highly neutralized polymers, polybutadienes,
polyurethanes, polyesters, thermoplastic elastomers, and other
conventional polymeric materials. Particularly suitable as a core
layer material is DuPont.RTM. HPF 1000, commercially available from
E. I. du Pont de Nemours and Company. Suitable HNP compositions are
further disclosed, for example, in U.S. Pat. Nos. 6,653,382,
6,756,436, 6,777,472, 6,894,098, 6,919,393, and 6,953,820, the
entire disclosures of which are hereby incorporated herein by
reference.
[0017] Suitable rubber compositions for use in forming the core
comprise a base rubber, a crosslinking agent, a filler, and a
co-crosslinking or initiator agent. Typical base rubber materials
include natural and synthetic rubbers, and combinations of two or
more thereof. The base rubber is preferably polybutadiene or a
mixture of polybutadiene with other elastomers. Particularly
preferred is 1,4-polybutadiene having a cis-structure of at least
40%. More preferably, the base rubber is a high-Mooney-viscosity
rubber. Lesser amounts of other thermoset materials may be
incorporated into the base rubber. Such materials include, for
example, cis-polyisoprene, trans-polyisoprene, balata,
polychloroprene, polynorbornene, polyoctenamer, polypentenamer,
butyl rubber, EPR, EPDM, styrene-butadiene, and similar thermoset
materials. The crosslinking agent typically includes a metal salt,
such as a zinc-, aluminum-, sodium-, lithium-, nickel-, calcium-,
or magnesium- salt, of an unsaturated fatty acid or monocarboxylic
acid, such as (meth) acrylic acid. Preferred crosslinking agents
include zinc acrylate, zinc diacrylate (ZDA), zinc methacrylate,
and zinc dimethacrylate (ZDMA), and mixtures thereof. The
crosslinking agent must be present in an amount sufficient to
crosslink a portion of the chains of the polymers in the resilient
polymer component. The crosslinking agent is generally present in
the rubber composition in an amount of from 15 to 30 phr, or from
19 to 25 phr, or from 20 to 24 phr. The desired compression may be
obtained by adjusting the amount of crosslinking, which can be
achieved, for example, by altering the type and amount of
crosslinking agent. The initiator agent can be any known
polymerization initiator which decomposes during the cure cycle,
including, but not limited to, dicumyl peroxide,
1,1-di-(t-butylperoxy) 3,3,5-trimethyl cyclohexane, a-a
bis-(t-butylperoxy) diisopropylbenzene, 2,5-di-(t-butylperoxy)
-2,5-dimethyl hexane, di-t-butyl peroxide,
n-butyl-4,4-bis(t-butylperoxy)valerate, lauryl peroxide, benzoyl
peroxide, t-butyl hydroperoxide, and mixtures thereof.
[0018] The rubber composition optionally contains one or more
antioxidants. Antioxidants are compounds that can inhibit or
prevent the oxidative degradation of the rubber. Some antioxidants
also act as free radical scavengers; thus, when antioxidants are
included in the rubber composition, the amount of initiator agent
used may be as high or higher than the amounts disclosed herein.
Suitable antioxidants include, for example, dihydroquinoline
antioxidants, amine type antioxidants, and phenolic type
antioxidants.
[0019] The rubber composition may also contain one or more fillers
to adjust the density and/or specific gravity of the core or cover.
Fillers are typically polymeric or mineral particles. Exemplary
fillers include precipitated hydrated silica, clay, talc, asbestos,
glass fibers, aramid fibers, mica, calcium metasilicate, zinc
sulfate, barium sulfate, zinc sulfide, lithopone, silicates,
silicon carbide, diatomaceous earth, polyvinyl chloride, carbonates
(e.g., calcium carbonate, zinc carbonate, barium carbonate, and
magnesium carbonate), metals (e.g., titanium, tungsten, aluminum,
bismuth, nickel, molybdenum, iron, lead, copper, boron, cobalt,
beryllium, zinc, and tin), metal alloys (e.g., steel, brass,
bronze, boron carbide whiskers, and tungsten carbide whiskers),
oxides (e.g., zinc oxide, tin oxide, iron oxide, calcium oxide,
aluminum oxide, titanium dioxide, magnesium oxide, and zirconium
oxide), particulate carbonaceous materials (e.g., graphite, carbon
black, cotton flock, natural bitumen, cellulose flock, and leather
fiber), microballoons (e.g., glass and ceramic), fly ash, regrind
(i.e., core material that is ground and recycled), nanofillers and
combinations thereof. The amount of particulate material(s) present
in the rubber composition is typically within a range having a
lower limit of 5 parts or 10 parts by weight per 100 parts of the
base rubber, and an upper limit of 30 parts or 50 parts or 100
parts by weight per 100 parts of the base rubber. Filler materials
may be dual-functional fillers, such as zinc oxide (which may be
used as a filler/acid scavenger) and titanium dioxide (which may be
used as a filler/brightener material). Further examples of suitable
fillers and additives include, but are not limited to, those
disclosed in U.S. Patent Application Publication No. 2003/0225197,
the entire disclosure of which is hereby incorporated herein by
reference.
[0020] The rubber composition may also contain one or more
additives selected from processing aids, processing oils,
plasticizers, coloring agents, fluorescent agents, chemical blowing
and foaming agents, defoaming agents, stabilizers, softening
agents, impact modifiers, free radical scavengers, accelerators,
scorch retarders, and the like. The amount of additive(s) typically
present in the rubber composition is typically within a range
having a lower limit of 0 parts by weight per 100 parts of the base
rubber, and an upper limit of 20 parts or 50 parts or 100 parts or
150 parts by weight per 100 parts of the base rubber.
[0021] The rubber composition optionally includes a soft and fast
agent. As used herein, "soft and fast agent" means any compound or
a blend thereof that is capable of making a core 1) softer (have a
lower compression) at a constant COR and/or 2) faster (have a
higher COR at equal compression), when compared to a core
equivalently prepared without a soft and fast agent. Preferably,
the rubber composition contains from 0.05 phr to 10.0 phr of a soft
and fast agent. In one embodiment, the soft and fast agent is
present in an amount of from 0.05 phr to 3.0 phr, or from 0.05 phr
to 2.0 phr, or from 0.05 phr to 1.0 phr. In another embodiment, the
soft and fast agent is present in an amount of from 2.0 phr to 5.0
phr, or from 2.35 phr to 4.0 phr, or from 2.35 phr to 3.0 phr. In
an alternative high concentration embodiment, the soft and fast
agent is present in an amount of from 5.0 phr to 10.0 phr, or from
6.0 phr to 9.0 phr, or from 7.0 phr to 8.0 phr. In another
embodiment, the soft and fast agent is present in an amount of 2.6
phr.
[0022] Suitable soft and fast agents include, but are not limited
to, organosulfur or metal-containing organosulfur compounds, an
organic sulfur compound, including mono, di, and polysulfides, a
thiol, or mercapto compound, an inorganic sulfide compound, a Group
VIA compound, a substituted or unsubstituted aromatic organic
compound that does not contain sulfur or metal, an aromatic
organometallic compound, or mixtures thereof. The soft and fast
agent component may also be a blend of an organosulfur compound and
an inorganic sulfide compound.
[0023] Suitable soft and fast agents of the present invention
include, but are not limited to those having the following general
formula:
##STR00001##
where R.sub.1-R.sub.5 can be C.sub.1-C.sub.8 alkyl groups; halogen
groups; thiol groups (--SH), carboxylated groups; sulfonated
groups; and hydrogen; in any order; and also pentafluorothiophenol;
2-fluorothiophenol; 3-fluorothiophenol; 4-fluorothiophenol;
2,3-fluorothiophenol; 2,4-fluorothiophenol; 3,4-fluorothiophenol;
3,5-fluorothiophenol 2,3,4-fluorothiophenol;
3,4,5-fluorothiophenol; 2,3,4,5-tetrafluorothiophenol;
2,3,5,6-tetrafluorothiophenol; 4-chlorotetrafluorothiophenol;
pentachlorothiophenol; 2-chlorothiophenol; 3-chlorothiophenol;
4-chlorothiophenol; 2,3-chlorothiophenol; 2,4-chlorothiophenol;
3,4-chlorothiophenol; 3,5-chlorothiophenol; 2,3,4-chlorothiophenol;
3,4,5-chlorothiophenol; 2,3,4,5-tetrachlorothiophenol;
2,3,5,6-tetrachlorothiophenol; pentabromothiophenol;
2-bromothiophenol; 3-bromothiophenol; 4-bromothiophenol;
2,3-bromothiophenol; 2,4-bromothiophenol; 3,4-bromothiophenol;
3,5-bromothiophenol; 2,3,4-bromothiophenol; 3,4,5-bromothiophenol;
2,3,4,5-tetrabromothiophenol; 2,3,5,6-tetrabromothiophenol;
pentaiodothiophenol; 2-iodothiophenol; 3-iodothiophenol;
4-iodothiophenol; 2,3-iodothiophenol; 2,4-iodothiophenol;
3,4-iodothiophenol; 3,5-iodothiophenol; 2,3,4-iodothiophenol;
3,4,5-iodothiophenol; 2,3,4,5-tetraiodothiophenol;
2,3,5,6-tetraiodothiophenoland; zinc salts thereof; non-metal salts
thereof, for example, ammonium salt of pentachlorothiophenol;
magnesium pentachlorothiophenol; cobalt pentachlorothiophenol; and
mixtures thereof. Preferably, the halogenated thiophenol compound
is pentachlorothiophenol, which is commercially available in neat
form or under the tradename STRUKTOL.RTM., a clay-based carrier
containing the sulfur compound pentachlorothiophenol loaded at 45
percent (correlating to 2.4 parts PCTP). STRUKTOL.RTM. is
commercially available from Struktol Company of America of Stow,
Ohio. PCTP is commercially available in neat form from eChinachem
of San Francisco, Calif. and in the salt form from eChinachem of
San Francisco, Calif. Most preferably, the halogenated thiophenol
compound is the zinc salt of pentachlorothiophenol, which is
commercially available from eChinachem of San Francisco, Calif.
Additional examples are disclosed in U.S. Pat. No. 7,148,279, the
entire disclosure of which is hereby incorporated herein by
reference.
[0024] As used herein, "organosulfur compound(s)" refers to any
compound containing carbon, hydrogen, and sulfur, where the sulfur
is directly bonded to at least 1 carbon. As used herein, the term
"sulfur compound" means a compound that is elemental sulfur,
polymeric sulfur, or a combination thereof. It should be further
understood that the term "elemental sulfur" refers to the ring
structure of S.sub.8 and that "polymeric sulfur" is a structure
including at least one additional sulfur relative to elemental
sulfur.
[0025] Additional suitable examples of soft and fast agents
include, but are not limited to, 4,4'-diphenyl disulfide;
4,4'-ditolyl disulfide; 2,2'-benzamido diphenyl disulfide;
bis(2-aminophenyl) disulfide; bis(4-aminophenyl) disulfide;
bis(3-aminophenyl) disulfide; 2,2'-bis(4-aminonaphthyl) disulfide;
2,2'-bis(3-aminonaphthyl) disulfide; 2,2'-bis(4-aminonaphthyl)
disulfide; 2,2'-bis(5-aminonaphthyl) disulfide;
2,2'-bis(6-aminonaphthyl) disulfide; 2,2'-bis(7-aminonaphthyl)
disulfide; 2,2'-bis(8-aminonaphthyl) disulfide;
1,1'-bis(2-aminonaphthyl) disulfide; 1,1'-bis(3-aminonaphthyl)
disulfide; 1,1'-bis(3-aminonaphthyl) disulfide;
1,1'-bis(4-aminonaphthyl) disulfide; 1,1'-bis(5-aminonaphthyl)
disulfide; 1,1'-bis(6-aminonaphthyl) disulfide;
1,1'-bis(7-aminonaphthyl) disulfide; 1,1'-bis(8-aminonaphthyl)
disulfide; 1,2'-diamino-1,2'-dithiodinaphthalene;
2,3'-diamino-1,2'-dithiodinaphthalene; bis(4-chlorophenyl)
disulfide; bis(2-chlorophenyl) disulfide; bis(3-chlorophenyl)
disulfide; bis(4-bromophenyl) disulfide; bis(2-bromophenyl)
disulfide; bis(3-bromophenyl) disulfide; bis(4-fluorophenyl)
disulfide; bis(4-iodophenyl) disulfide; bis(2,5-dichlorophenyl)
disulfide; bis(3,5-dichlorophenyl) disulfide;
bis(2,4-dichlorophenyl) disulfide; bis(2,6-dichlorophenyl)
disulfide; bis(2,5-dibromophenyl) disulfide; bis(3,5-dibromophenyl)
disulfide; bis(2-chloro-5-bromophenyl) disulfide;
bis(2,4,6-trichlorophenyl) disulfide;
bis(2,3,4,5,6-pentachlorophenyl) disulfide; bis(4-cyanophenyl)
disulfide; bis(2-cyanophenyl) disulfide; bis(4-nitrophenyl)
disulfide; bis(2-nitrophenyl) disulfide; 2,2'-dithiobenzoic acid
ethylester; 2,2'-dithiobenzoic acid methylester; 2,2'-dithiobenzoic
acid; 4,4'-dithiobenzoic acid ethylester; bis(4-acetylphenyl)
disulfide; bis(2-acetylphenyl) disulfide; bis(4-formylphenyl)
disulfide; bis(4-carbamoylphenyl) disulfide; 1,1'-dinaphthyl
disulfide; 2,2'-dinaphthyl disulfide; 1,2'-dinaphthyl disulfide;
2,2'-bis(1-chlorodinaphthyl) disulfide; 2,2'-bis(1-bromonaphthyl)
disulfide; 1,1'-bis(2-chloronaphthyl) disulfide;
2,2'-bis(1-cyanonaphthyl) disulfide; 2,2'-bis(1-acetylnaphthyl)
disulfide; and the like; or a mixture thereof. Preferred
organosulfur components include 4,4'-diphenyl disulfide,
4,4'-ditolyl disulfide, or 2,2'-benzamido diphenyl disulfide, or a
mixture thereof. A preferred organosulfur component includes
4,4'-ditolyl disulfide.
[0026] In another embodiment, metal-containing organosulfur
components can be used according to the invention. Suitable
metal-containing organosulfur components include, but are not
limited to, cadmium, copper, lead, and tellurium analogs of
diethyldithiocarbamate, diamyldithiocarbamate, and
dimethyldithiocarbamate, or mixtures thereof. Additional examples
are disclosed in U.S. Pat. No. 7,005,479, the entire disclosure of
which is hereby incorporated herein by reference.
[0027] Suitable substituted or unsubstituted aromatic organic
components that do not include sulfur or a metal include, but are
not limited to, 4,4'-diphenyl acetylene, azobenzene, or a mixture
thereof. The aromatic organic group preferably ranges in size from
C.sub.6 to C.sub.20, and more preferably from C.sub.6 to C.sub.10.
Suitable inorganic sulfide components include, but are not limited
to titanium sulfide, manganese sulfide, and sulfide analogs of
iron, calcium, cobalt, molybdenum, tungsten, copper, selenium,
yttrium, zinc, tin, and bismuth.
[0028] A substituted or unsubstituted aromatic organic compound is
also suitable as a soft and fast agent. Suitable substituted or
unsubstituted aromatic organic components include, but are not
limited to, components having the formula
(R.sub.1).sub.x-R.sub.3-M-R.sub.4-(R.sub.2).sub.y, wherein R.sub.1
and R.sub.2 are each hydrogen or a substituted or unsubstituted
C.sub.1-20 linear, branched, or cyclic alkyl, alkoxy, or alkylthio
group, or a single, multiple, or fused ring C.sub.6 to C.sub.24
aromatic group; x and y are each an integer from 0 to 5; R.sub.3
and R.sub.4 are each selected from a single, multiple, or fused
ring C.sub.6 to C.sub.24 aromatic group; and M includes an azo
group or a metal component. R.sub.3 and R.sub.4 are each preferably
selected from a C.sub.6 to C.sub.10 aromatic group, more preferably
selected from phenyl, benzyl, naphthyl, benzamido, and
benzothiazyl. R.sub.1 and R.sub.2 are each preferably selected from
a substituted or unsubstituted C.sub.1-10 linear, branched, or
cyclic alkyl, alkoxy, or alkylthio group or a C.sub.6 to C.sub.10
aromatic group. When R.sub.1, R.sub.2, R.sub.3, or R.sub.4, are
substituted, the substitution may include one or more of the
following substituent groups: hydroxy and metal salts thereof;
mercapto and metal salts thereof; halogen; amino, nitro, cyano, and
amido; carboxyl including esters, acids, and metal salts thereof;
silyl; acrylates and metal salts thereof; sulfonyl or sulfonamide;
and phosphates and phosphites. When M is a metal component, it may
be any suitable elemental metal available to those of ordinary
skill in the art. Typically, the metal will be a transition metal,
although preferably it is tellurium or selenium. In one embodiment,
the aromatic organic compound is substantially free of metal, while
in another embodiment the aromatic organic compound is completely
free of metal.
[0029] The soft and fast agent can also include a Group VIA
component. Elemental sulfur and polymeric sulfur are commercially
available from Elastochem, Inc. of Chardon, Ohio. Exemplary sulfur
catalyst compounds include PB(RM-S)-80 elemental sulfur and
PB(CRST)-65 polymeric sulfur, each of which is available from
Elastochem, Inc. An exemplary tellurium catalyst under the
tradename TELLOY.RTM. and an exemplary selenium catalyst under the
tradename VANDEX.RTM. are each commercially available from RT
Vanderbilt.
[0030] Other suitable soft and fast agents include, but are not
limited to, hydroquinones, benzoquinones, quinhydrones, catechols,
and resorcinols. Suitable hydroquinones are further disclosed, for
example, in U.S. Patent Application Publication No. 2007/0213440.
Suitable benzoquinones are further disclosed, for example, in U.S.
Patent Application Publication No. 2007/0213442. Suitable
quinhydrones are further disclosed, for example, in U.S. Patent
Application Publication No. 2007/0213441. Suitable catechols and
resorcinols are further disclosed, for example, in U.S. Patent
Application Publication No. 2007/0213144. The entire disclosure of
each of these references is hereby incorporated herein by
reference.
[0031] In a particular embodiment, the soft and fast agent is a
catechol selected from one or more compounds represented by the
following formula, and hydrates thereof:
##STR00002##
[0032] wherein each R.sub.1, R.sub.2, R.sub.3, and R.sub.4, is
independently selected from the group consisting of hydrogen, a
halogen group (F, Cl, Br, I), an alkyl group, a carboxyl group
(--COOH) and metal salts thereof (e.g., --COO.sup.-M.sup.+) and
esters thereof (--COOR), an acetate group (--CH.sub.2COOH) and
esters thereof (--CH.sub.2COOR), a formyl group (--CHO), an acyl
group (--COR), an acetyl group (--COCH.sub.3), a halogenated
carbonyl group (--COX), a sulfo group (--SO.sub.3H) and esters
thereof (--SO.sub.3R), a halogenated sulfonyl group (--SO.sub.2X),
a sulfino group (--SO.sub.2H), an alkylsulfinyl group (--SOR), a
carbamoyl group (--CONH.sub.2), a halogenated alkyl group, a cyano
group (--CN), an alkoxy group (--OR), a hydroxy group (--OH) and
metal salts thereof (e.g., --O.sup.-M.sup.+), an amino group
(--NH.sub.2), a nitro group (--NO.sub.2), an aryl group (e.g.,
phenyl, tolyl, etc.), an aryloxy group (e.g., phenoxy, etc.), an
arylalkyl group [e.g., cumyl (--C(CH.sub.3).sub.2phenyl); benzyl
(--CH.sub.2 phenyl)], a nitroso group (--NO), an acetamido group
(--NHCOCH.sub.3), and a vinyl group (--CH.dbd.CH.sub.2).
[0033] In another particular embodiment, the soft and fast agent is
a resorcinol selected from one or more compounds represented by the
following formula, and hydrates thereof:
##STR00003##
[0034] wherein each R.sub.1, R.sub.2, R.sub.3, and R.sub.4, is
independently selected from the group consisting of hydrogen, a
halogen group (F, Cl, Br, I), an alkyl group, a carboxyl group
(--COOH) and metal salts thereof (e.g., --COO.sup.-M.sup.+) and
esters thereof (--COOR), an acetate group (--CH.sub.2COOH) and
esters thereof (--CH.sub.2COOR), a formyl group (--CHO), an acyl
group (--COR), an acetyl group (--COCH.sub.3), a halogenated
carbonyl group (--COX), a sulfo group (--SO.sub.3H) and esters
thereof (--SO.sub.3R), a halogenated sulfonyl group (--SO.sub.2X),
a sulfino group (--SO.sub.2H), an alkylsulfinyl group (--SOR), a
carbamoyl group (--CONH.sub.2), a halogenated alkyl group, a cyano
group (--CN), an alkoxy group (--OR), a hydroxy group (--OH) and
metal salts thereof (e.g., --O.sup.-M.sup.+), an amino group
(--NH.sub.2), a nitro group (--NO.sub.2), an aryl group (e.g.,
phenyl, tolyl, etc.), an aryloxy group (e.g., phenoxy, etc.), an
arylalkyl group [e.g., cumyl (--C(CH.sub.3).sub.2phenyl); benzyl
(--CH.sub.2 phenyl)], a nitroso group (--NO), an acetamido group
(--NHCOCH.sub.3), and a vinyl group (--CH.dbd.CH.sub.2).
[0035] The soft and fast agent may be a combination of one or more
catechols, each of which is independently selected from compounds
represented by the above formula; a combination of one or more
resorcinols, each of which is independently selected from compounds
represented by the above formula; a combination of at least one
catechol and one or more non-catechol soft and fast agents
including, but not limited to, hydroquinones, benzoquinones,
quinhydrones, and resorcinols; or a combination of at least one
resorcinol and one or more non-resorcinol soft and fast agents
including, but not limited to, hydroquinones, benzoquinones,
quinhydrones, and catechols.
[0036] The catechol or resorcinol is typically used in the form of
a liquid or solid. In a particular embodiment, the catechol or
resorcinol is used in a solid form and may be synthesized or
processed so as to have a particle size of 0.25 mm or less, or
0.125 mm or less, or 0.09 mm or less. In another particular
embodiment, the catechol or resorcinol is used in a solid form and
melts at 150.degree. F. or less, or 120.degree. F. or less, or at a
temperature that is the same as or less than the mixing temperature
of the base rubber.
[0037] When the soft and fast agent includes catechol(s) and/or
resorcinol(s), the total amount of catechol(s) and/or resorcinol(s)
present in the rubber composition is typically at least 0.1 parts
by weight or at least 0.15 parts by weight or at least 0.2 parts by
weight per 100 parts of the base rubber, or an amount within the
range having a lower limit of 0.1 parts or 0.15 parts or 0.25 parts
or 0.3 parts or 0.375 parts by weight per 100 parts of the base
rubber, and an upper limit of 0.5 parts or 1 part or 1.5 parts or 2
parts or 3 parts by weight per 100 parts of the base rubber.
[0038] In a particular embodiment, the soft and fast agent
comprises a catechol, and a ratio (P.sub.CATECHOL/P.sub.INITIATOR)
of the amount of the catechol present in the rubber composition
(P.sub.CATECHOL) measured in parts by weight per 100 parts of the
base rubber, to the amount of initiator agent present in the rubber
composition (P.sub.INITIATOR), measured in parts by weight per 100
parts of the base rubber, is from 0.05 to 2. In another embodiment,
P.sub.CATECHOL/P.sub.INITIATOR is at least 0.05 and less than 0.5.
In another embodiment, P.sub.CATECHOL/P.sub.INITIATOR is at least
0.2 and less than 0.5. In another embodiment,
P.sub.CATECHOL/P.sub.INITIATOR is at least 0.25 and less than 0.5.
In yet another embodiment, P.sub.CATECHOL/P.sub.INITIATOR is within
the range having a lower limit of 0.05 or 0.2 or 0.25 and an upper
limit of 0.4 or 0.45 or 0.5 or 2.
[0039] In another particular embodiment, the soft and fast agent
comprises a resorcinol, and a ratio
(P.sub.RESORCINOL/P.sub.INITIATOR) of the amount of the resorcinol
present in the rubber composition (P.sub.RESORCINOL) measured in
parts by weight per 100 parts of the base rubber, to the amount of
initiator agent present in the rubber composition
(P.sub.INITIATOR), measured in parts by weight per 100 parts of the
base rubber, is from 0.05 to 2. In another embodiment,
P.sub.RESORCINOL/P.sub.INITIATOR is at least 0.05 and less than
0.5. In another embodiment, P.sub.RESORCINOL/P.sub.INITIATOR is at
least 0.2 and less than 0.5. In another embodiment,
P.sub.RESORCINOL/P.sub.INITIATOR is at least 0.25 and less than
0.5. In yet another embodiment, P.sub.RESORCINOL/P.sub.INITIATOR is
within the range having a lower limit of 0.05 or 0.2 or 0.25 and an
upper limit of 0.4 or 0.45 or 0.5 or 2.
[0040] Examples of commercially available polybutadienes suitable
for use in forming the core include, but are not limited to, Buna
CB 23, commercially available from LANXESS Corporation; SE BR-1220,
commercially available from The Dow Chemical Company;
Europrene.RTM. NEOCIS.RTM. BR 40 and BR 60, commercially available
from Polimeri Europa; UBEPOL-BR.RTM. rubbers, commercially
available from UBE Industries, Ltd.; and BR 01 commercially
available from Japan Synthetic Rubber Co., Ltd.
[0041] Suitable types and amounts of base rubber, crosslinking
agent, filler, co-crosslinking agent, initiator agent and additives
are more fully described in, for example, U.S. Patent Application
Publication Nos. 2004/0214661, 2003/0144087, and 2003/0225197, and
U.S. Pat. Nos. 6,566,483, 6,695,718, and 6,939,907, the entire
disclosures of which are hereby incorporated herein by
reference.
[0042] The core can also be formed from a low deformation material
selected from metal, rigid plastics, polymers reinforced with high
strength organic or inorganic fillers or fibers, and blends and
composites thereof. Suitable low deformation materials also include
those disclosed in U.S. Patent Application Publication No.
2005/0250600, the entire disclosure of which is hereby incorporated
herein by reference.
[0043] The core may also comprise thermosetting or thermoplastic
materials such as polyurethane, polyurea, partially or fully
neutralized ionomers, thermosetting polydiene rubber such as
polybutadiene, polyisoprene, ethylene propylene diene monomer
rubber, ethylene propylene rubber, natural rubber, balata, butyl
rubber, halobutyl rubber, styrene butadiene rubber or any styrenic
block copolymer such as styrene ethylene butadiene styrene rubber,
etc., metallocene or other single site catalyzed polyolefin,
polyurethane copolymers, e.g., with silicone, as long as the
material meets the desired coefficient of restitution ("COR").
[0044] Additional materials suitable for forming the core include
the core compositions disclosed in U.S. Pat. No. 7,300,364, the
entire disclosure of which is hereby incorporated herein by
reference. For example, suitable core materials include HNPs
neutralized with organic fatty acids and salts thereof, metal
cations, or a combination of both. In addition to HNPs neutralized
with organic fatty acids and salts thereof, core compositions may
comprise at least one rubber material having a resilience index of
at least about 40. Preferably the resilience index is at least
about 50. Polymers that produce resilient golf balls and,
therefore, are suitable for the present invention, include but are
not limited to CB23, CB22, commercially available from of Bayer
Corp. of Orange, Tex., BR60, commercially available from Enichem of
Italy, and 1207G, commercially available from Goodyear Corp. of
Akron, Ohio. Additionally, the unvulcanized rubber, such as
polybutadiene, in golf balls prepared according to the invention
typically has a Mooney viscosity of between about 40 and about 80,
more preferably, between about 45 and about 65, and most
preferably, between about 45 and about 55. Mooney viscosity is
typically measured according to ASTM-D1646.
[0045] The core is enclosed with a cover comprising an inner cover
layer and an outer cover layer. According to the present invention,
the surface hardness of the core is greater than the material
hardness of the inner cover layer. In a particular embodiment, the
surface hardness of the core is greater than both the inner cover
layer and the outer cover layer.
[0046] 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 disclosure,
material hardness is measured according to ASTM D2240 and generally
involves measuring the hardness of a flat "slab" or "button" formed
of the material. Hardness as measured directly on a golf ball (or
other spherical surface) typically results in a different hardness
value. This difference in hardness values is due to several factors
including, but not limited to, ball construction (i.e., core type,
number of core and/or cover layers, etc.), ball (or sphere)
diameter, and the material composition of adjacent layers. It
should also be understood that the two measurement techniques are
not linearly related and, therefore, one hardness value cannot
easily be correlated to the other. The hardness values given herein
for cover materials, including inner cover layer materials and
outer cover layer materials, are material hardness values measured
according to ASTM D2240, with all values reported following 10 days
of aging at 50% relative humidity and 23.degree. C.
[0047] The inner cover layer preferably has a material hardness of
90 Shore C or less, or 85 Shore C or less, or a material hardness
of from 80 Shore C to 90 Shore C, or a material hardness within a
range having a lower limit of 70 or 75 or 80 or 82 Shore C and an
upper limit of 85 or 86 or 90 Shore C. The thickness of the inner
cover layer is preferably within a range having a lower limit of
0.010 or 0.015 or 0.020 or 0.030 inches and an upper limit of 0.035
or 0.045 or 0.080 or 0.120 inches.
[0048] The outer cover layer preferably has a material hardness of
85 Shore C or less. The thickness of the outer cover layer is
preferably within a range having a lower limit of 0.010 or 0.015 or
0.025 inches and an upper limit of 0.035 or 0.040 or 0.055 or 0.080
inches.
[0049] Suitable materials for forming the inner and outer cover
layer include ionomer resins and blends thereof (particularly
Surlyn.RTM. ionomer resins), polyurethanes, polyureas,
(meth)acrylic acid, thermoplastic rubber polymers, polyethylene,
and synthetic or natural vulcanized rubber, such as balata.
Suitable commercially available ionomeric cover materials include,
but are not limited to, Surlyn.RTM. ionomer resins and DuPont.RTM.
HPF 1000 and HPF 2000, commercially available from E. I. du Pont de
Nemours and Company; and Iotek.RTM. ionomers, commercially
available from ExxonMobil Chemical Company.
[0050] Also suitable for forming cover layers are blends of
ionomers with thermoplastic elastomers. Suitable ionomeric cover
materials are further disclosed, for example, in U.S. Pat. Nos.
6,653,382, 6,756,436, 6,894,098, 6,919,393, and 6,953,820, the
entire disclosures of which are hereby incorporated by reference.
Suitable polyurethane cover materials are further disclosed in U.S.
Pat. Nos. 5,334,673, 6,506,851, and 6,756,436, the entire
disclosures of which are hereby incorporated herein by reference.
Suitable polyurea cover materials are further disclosed in U.S.
Pat. Nos. 5,484,870 and 6,835,794, the entire disclosures of which
are hereby incorporated herein by reference. Suitable
polyurethane-urea hybrids are blends or copolymers comprising
urethane or urea segments as disclosed in U.S. Patent Application
Publication No. 2007/0117923, the entire disclosure of which is
hereby incorporated herein by reference. Additional suitable cover
materials are disclosed, for example, in U.S. Patent Application
Publication No. 2005/0164810, U.S. Pat. No. 5,919,100, and PCT
Publications WO00/23519 and WO00/29129, the entire disclosures of
which are hereby incorporated herein by reference.
[0051] The inner cover layer is preferably formed from a
composition comprising an ionomer or a blend of two or more
ionomers. In a particular embodiment, the inner cover layer is
formed from a composition comprising a high acid ionomer. For
purposes of the present disclosure, "high acid ionomer" includes
ionomers having an acid content of greater than 16 wt %. A
particularly suitable high acid ionomer is Surlyn 8150.RTM.,
commercially available from E. I. du Pont de Nemours and Company.
Surlyn 8150.RTM. is a copolymer of ethylene and methacrylic acid,
having an acid content of 19 wt %, which is 45% neutralized with
sodium. In another particular embodiment, the inner cover layer is
formed from a composition comprising a high acid ionomer and a
maleic anhydride-grafted non-ionomeric polymer. A particularly
suitable maleic anhydride-grafted polymer is Fusabond 572D.RTM.,
commercially available from E. I. du Pont de Nemours and Company.
Fusabond 572D.RTM. is a maleic anhydride-grafted,
metallocene-catalyzed ethylene-butene copolymer having about 0.9 wt
% maleic anhydride grafted onto the copolymer. A particularly
preferred blend of high acid ionomer and maleic anhydride-grafted
polymer is a 84 wt %/16 wt % blend of Surlyn 8150.RTM. and Fusabond
572D.RTM.. Blends of high acid ionomers with maleic
anhydride-grafted polymers are further disclosed, for example, in
U.S. Pat. Nos. 6,992,135 and 6,677,401, the entire disclosures of
which are hereby incorporated herein by reference.
[0052] In another particular embodiment, the inner cover layer is
preferably formed from a composition comprising a 50/45/5 blend of
Surlyn.RTM. 8940/Surlyn.RTM. 9650/Nucrel.RTM. 960, and, in a
particularly preferred embodiment, has a material hardness of from
80 to 85 Shore C. In another particular embodiment, the inner cover
layer is preferably formed from a composition comprising a 50/25/25
blend of Surlyn.RTM. 8940/Surlyn.RTM. 9650/Surlyn.RTM. 9910,
preferably having a material hardness of about 90 Shore C. In yet
another particular embodiment, the inner cover layer is preferably
formed from a composition comprising a 50/50 blend of Surlyn.RTM.
8940/Surlyn.RTM. 9650, preferably having a material hardness of
about 86 Shore C. Surlyn.RTM. 8940 is an E/MAA copolymer in which
the MAA acid groups have been partially neutralized with sodium
ions. Surlyn.RTM. 9650 and Surlyn.RTM. 9910 are two different
grades of E/MAA copolymer in which the MAA acid groups have been
partially neutralized with zinc ions. Nucrel.RTM. 960 is an E/MAA
copolymer resin nominally made with 15 wt % methacrylic acid.
Surlyn.RTM. 8940, Surlyn.RTM. 9650, Surlyn.RTM. 9910, and
Nucrel.RTM. 960 are commercially available from E. I. du Pont de
Nemours and Company.
[0053] Non-limiting examples of preferred inner cover layer
materials are shown in the Examples below.
[0054] Ionomeric compositions of the present invention can be
blended with non-ionic thermoplastic resins, particularly to
manipulate product properties. Examples of suitable non-ionic
thermoplastic resins include, but are not limited to, polyurethane,
poly-ether-ester, poly-amide-ether, polyether-urea, Pebax.RTM.
thermoplastic polyether block amides commercially available from
Arkema Inc., styrene-butadiene-styrene block copolymers,
styrene(ethylene-butylene)-styrene block copolymers, polyamides,
polyesters, polyolefins (e.g., polyethylene, polypropylene,
ethylene-propylene copolymers, ethylene-(meth)acrylate,
ethylene-(meth)acrylic acid, functionalized polymers with maleic
anhydride grafting, Fusabond.RTM. functionalized olefins
commercially available from E. I. du Pont de Nemours and Company,
functionalized polymers with epoxidation, elastomers (e.g., EPDM,
metallocene-catalyzed polyethylene) and ground powders of the
thermoset elastomers.
[0055] The inner cover layer material may include a flow modifier,
such as, but not limited to, Nucrel.RTM. acid copolymer resins, and
particularly Nucrel.RTM. 960. Nucrel.RTM. acid copolymer resins are
commercially available from E. I. du Pont de Nemours and
Company.
[0056] The outer cover layer is preferably formed from a
composition comprising polyurethane, polyurea, or a copolymer or
hybrid of polyurethane/polyurea. The outer cover layer material may
be thermoplastic or thermoset.
[0057] In a particularly preferred embodiment, the present
invention provides a golf ball consisting of: a single-layer core,
an inner cover layer, and an outer cover layer. The core is
preferably formed from a rubber composition and, in a particularly
preferred embodiment, has one or more of the following properties:
a diameter of about 1.53 inches, a compression of about 70, a
center hardness of about 60 Shore C, and a surface hardness of
about 85 Shore C. The rubber composition preferably has the
following formulation: 100 parts high-cis butadiene rubber, 30 phr
zinc diacrylate, 5 phr zinc oxide, BaSO.sub.4 in amount necessary
to achieve the desired specific gravity, 0.5 phr zinc
pentachlorothiophenol, 1.2 phr Perkadox BC, and from 10 to 20 phr
regrind material. The inner cover layer is preferably formed from a
composition comprising a 84 wt %/16 wt % blend of Surlyn 8150.RTM.
and Fusabond 572D.RTM.. The outer cover layer is preferably formed
from a polyurethane or polyurea composition.
[0058] A moisture vapor barrier layer is optionally employed
between the core and the cover. Moisture vapor barrier layers are
further disclosed, for example, in U.S. Pat. Nos. 6,632,147,
6,932,720, 7,004,854, and 7,182,702, the entire disclosures of
which are hereby incorporated herein by reference.
[0059] In addition to the materials disclosed above, any of the
core or cover layers may comprise one or more of the following
materials: thermoplastic elastomer, thermoset elastomer, synthetic
rubber, thermoplastic vulcanizate, copolymeric ionomer,
terpolymeric ionomer, polycarbonate, polyolefin, polyamide,
copolymeric polyamide, polyesters, polyester-amides,
polyether-amides, polyvinyl alcohols,
acrylonitrile-butadiene-styrene copolymers, polyarylate,
polyacrylate, polyphenylene ether, impact-modified polyphenylene
ether, high impact polystyrene, diallyl phthalate polymer,
metallocene-catalyzed polymers, styrene-acrylonitrile (SAN),
olefin-modified SAN, acrylonitrile-styrene-acrylonitrile,
styrene-maleic anhydride (S/MA) polymer, styrenic copolymer,
functionalized styrenic copolymer, functionalized styrenic
terpolymer, styrenic terpolymer, cellulose polymer, liquid crystal
polymer (LCP), ethylene-propylene-diene rubber (EPDM),
ethylene-vinyl acetate copolymer (EVA), ethylene propylene rubber
(EPR), ethylene vinyl acetate, polyurea, and polysiloxane. Suitable
polyamides for use as an additional material in compositions
disclosed herein also include resins obtained by: (1)
polycondensation of (a) a dicarboxylic acid, such as oxalic acid,
adipic acid, sebacic acid, terephthalic acid, isophthalic acid or
1,4-cyclohexanedicarboxylic acid, with (b) a diamine, such as
ethylenediamine, tetramethylenediamine, pentamethylenediamine,
hexamethylenediamine, or decamethylenediamine,
1,4-cyclohexyldiamine or m-xylylenediamine; (2) a ring-opening
polymerization of cyclic lactam, such as .epsilon.-caprolactam or
.omega.-laurolactam; (3) polycondensation of an aminocarboxylic
acid, such as 6-aminocaproic acid, 9-aminononanoic acid,
11-aminoundecanoic acid or 12-aminododecanoic acid; or (4)
copolymerzation of a cyclic lactam with a dicarboxylic acid and a
diamine. Specific examples of suitable polyamides include Nylon 6,
Nylon 66, Nylon 610, Nylon 11, Nylon 12, copolymerized Nylon, Nylon
MXD6, and Nylon 46.
[0060] Other preferred materials suitable for use as an additional
material in golf ball compositions disclosed herein include Skypel
polyester elastomers, commercially available from SK Chemicals of
South Korea; Septon.RTM. diblock and triblock copolymers,
commercially available from Kuraray Corporation of Kurashiki,
Japan; and Kraton.RTM. diblock and triblock copolymers,
commercially available from Kraton Polymers LLC of Houston,
Tex.
[0061] Ionomers are also well suited for blending with compositions
disclosed herein. Suitable ionomeric polymers include
.alpha.-olefin/unsaturated carboxylic acid copolymer- or
terpolymer-type ionomeric resins. Copolymeric ionomers are obtained
by neutralizing at least a portion of the carboxylic groups in a
copolymer of an .alpha.-olefin and an .alpha.,.beta.-unsaturated
carboxylic acid having from 3 to 8 carbon atoms, with a metal ion.
Terpolymeric ionomers are obtained by neutralizing at least a
portion of the carboxylic groups in a terpolymer of an
.alpha.-olefin, an .alpha.,.beta.-unsaturated carboxylic acid
having from 3 to 8 carbon atoms, and an .alpha.,.beta.-unsaturated
carboxylate having from 2 to 22 carbon atoms, with a metal ion.
Examples of suitable .alpha.-olefins for copolymeric and
terpolymeric ionomers include ethylene, propylene, 1-butene, and
1-hexene. Examples of suitable unsaturated carboxylic acids for
copolymeric and terpolymeric ionomers include acrylic, methacrylic,
ethacrylic, .alpha.-chloroacrylic, crotonic, maleic, fumaric, and
itaconic acid. Copolymeric and terpolymeric ionomers include
ionomers having varied acid contents and degrees of acid
neutralization, neutralized by monovalent or bivalent cations as
disclosed herein. Examples of commercially available ionomers
suitable for blending with compositions disclosed herein include
Surlyn.RTM. ionomer resins, commercially available from E. I. du
Pont de Nemours and Company, and Iotek.RTM. ionomers, commercially
available from ExxonMobil Chemical Company.
[0062] Silicone materials are also well suited for blending with
compositions disclosed herein. Suitable silicone materials include
monomers, oligomers, prepolymers, and polymers, with or without
adding reinforcing filler. One type of silicone material that is
suitable can incorporate at least 1 alkenyl group having at least 2
carbon atoms in their molecules. Examples of these alkenyl groups
include, but are not limited to, vinyl, allyl, butenyl, pentenyl,
hexenyl, and decenyl. The alkenyl functionality can be located at
any location of the silicone structure, including one or both
terminals of the structure. The remaining (i.e., non-alkenyl)
silicon-bonded organic groups in this component are independently
selected from hydrocarbon or halogenated hydrocarbon groups that
contain no aliphatic unsaturation. Non-limiting examples of these
include: alkyl groups, such as methyl, ethyl, propyl, butyl,
pentyl, and hexyl; cycloalkyl groups, such as cyclohexyl and
cycloheptyl; aryl groups, such as phenyl, tolyl, and xylyl; aralkyl
groups, such as benzyl and phenethyl; and halogenated alkyl groups,
such as 3,3,3-trifluoropropyl and chloromethyl. Another type of
suitable silicone material is one having hydrocarbon groups that
lack aliphatic unsaturation. Specific examples include:
trimethylsiloxy-endblocked dimethylsiloxane-methylhexenylsiloxane
copolymers; dimethylhexenylsiloxy-endblocked
dimethylsiloxane-methylhexenylsiloxane copolymers;
trimethylsiloxy-endblocked dimethylsiloxane-methylvinylsiloxane
copolymers; trimethylsiloxyl-endblocked
methylphenylsiloxane-dimethylsiloxane-methylvinysiloxane
copolymers; dimethylvinylsiloxy-endblocked dimethylpolysiloxanes;
dimethylvinylsiloxy-endblocked dimethylsiloxane-methylvinylsiloxane
copolymers; dimethylvinylsiloxy-endblocked
methylphenylpolysiloxanes; dimethylvinylsiloxy-endblocked
methylphenylsiloxane-dimethylsiloxane-methylvinylsiloxane
copolymers; and the copolymers listed above wherein at least one
group is dimethylhydroxysiloxy. Examples of commercially available
silicones suitable for blending with compositions disclosed herein
include Silastic.RTM. silicone rubber, commercially available from
Dow Coming Corporation of Midland, Mich.; Blensil.RTM. silicone
rubber, commercially available from General Electric Company of
Waterford, N.Y.; and Elastosil.RTM. silicones, commercially
available from Wacker Chemie AG of Germany.
[0063] Other types of copolymers can also be added to the golf ball
compositions disclosed herein. For example, suitable copolymers
comprising epoxy monomers include styrene-butadiene-styrene block
copolymers in which the polybutadiene block contains an epoxy
group, and styrene-isoprene-styrene block copolymers in which the
polyisoprene block contains epoxy. Examples of commercially
available epoxy functionalized copolymers include ESBS A1005, ESBS
A1010, ESBS A1020, ESBS AT018, and ESBS AT019 epoxidized
styrene-butadiene-styrene block copolymers, commercially available
from Daicel Chemical Industries, Ltd. of Japan.
[0064] Also suitable for forming the core are the compositions
having high COR when formed into solid spheres disclosed in U.S.
Patent Application Publication No. 2003/0130434 and U.S. Pat. No.
6,653,382, the entire disclosures of which are hereby incorporated
herein by reference.
[0065] The present invention is not limited by any particular
process for forming the golf ball layer(s). It should be understood
that the layer(s) can be formed by any suitable technique,
including injection molding, compression molding, casting, and
reaction injection molding.
[0066] Golf balls of the present invention typically have a
coefficient of restitution of 0.70 or greater, preferably 0.75 or
greater, and more preferably 0.78 or greater. Golf balls of the
present invention typically have a compression of 40 or greater, or
a compression within a range having a lower limit of 50 or 60 and
an upper limit of 100 or 120. Cured polybutadiene-based
compositions suitable for use in golf balls of the present
invention typically have a hardness of 15 Shore A or greater, and
preferably have a hardness of from 30 Shore A to 80 Shore D, more
preferably from 50 Shore A to 60 Shore D.
[0067] Golf balls of the present invention will typically have
dimple coverage of 60% or greater, preferably 65% or greater, and
more preferably 75% or greater.
[0068] The United States Golf Association specifications limit the
minimum size of a competition golf ball to 1.680 inches. There is
no specification as to the maximum diameter, and golf balls of any
size can be used for recreational play. Golf balls of the present
invention can have an overall diameter of any size. The preferred
diameter of the present golf balls is from 1.680 inches to 1.800
inches. More preferably, the present golf balls have an overall
diameter of from 1.680 inches to 1.760 inches, and even more
preferably from 1.680 inches to 1.740 inches.
[0069] Golf balls of the present invention preferably have a moment
of inertia ("MOI") of 70-95 gcm.sup.2, preferably 75-93 gcm.sup.2,
and more preferably 76-90 gcm.sup.2. For low MOI embodiments, the
golf ball preferably has an MOI of 85 gcm.sup.2 or less, or 83
gcm.sup.2 or less. For high MOI embodiment, the golf ball
preferably has an MOI of 86 gcm.sup.2 or greater, or 87 gcm.sup.2
or greater. MOI is measured on a model MOI-005-104 Moment of
Inertia Instrument manufactured by Inertia Dynamics of
Collinsville, Conn. The instrument is connected to a PC for
communication via a COMM port and is driven by MOI Instrument
Software version #1.2.
[0070] Golf ball cores of the present invention preferably have an
overall compression of from 50 to 90, or from 60 to 85, or from 60
to 80, or from 65 to 80, or an overall compression of about 70.
[0071] Compression is an important factor in golf ball design. For
example, the compression of the core can affect the ball's spin
rate off the driver and the feel. As disclosed in Jeff Dalton's
Compression by Any Other Name, Science and Golf IV, Proceedings of
the World Scientific Congress of Golf (Eric Thain ed., Routledge,
2002) ("J. Dalton"), 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. For purposes of the
present invention, "compression" refers to Atti compression and is
measured according to a known procedure, using an Atti compression
test device, wherein a piston is used to compress a ball against a
spring. The travel of the piston is fixed and the deflection of the
spring is measured. The measurement of the deflection of the spring
does not begin with its contact with the ball; rather, there is an
offset of approximately the first 1.25 mm (0.05 inches) of the
spring's deflection. Very low stiffness cores will not cause the
spring to deflect by more than 1.25 mm and therefore have a zero
compression measurement. The Atti compression tester is designed to
measure objects having a diameter of 42.7 mm (1.68 inches); thus,
smaller objects, such as golf ball cores, must be shimmed to a
total height of 42.7 mm to obtain an accurate reading. Conversion
from Atti compression to Riehle (cores), Riehle (balls), 100 kg
deflection, 130-10 kg deflection or effective modulus can be
carried out according to the formulas given in J. Dalton.
[0072] Golf ball cores of the present invention preferably have a
zero or positive hardness gradient. The hardness gradient is
defined by hardness measurements made at the surface of the inner
core (or outer core layer) and radially inward towards the center
of the inner core, typically at 2 mm increments. For purposes of
the present invention, the term "positive" with respect to the
hardness gradient refers to the result of subtracting the hardness
value at the innermost portion of the golf ball component from the
hardness value at the outer surface of the component. For example,
if the outer surface of a solid core has a higher hardness value
than the center (i.e., the surface is harder than the center), the
hardness gradient will be deemed a "positive" gradient. Hardness
gradients are measured by preparing the core according to the
procedure given above for measuring the center hardness of the
core. Hardness measurements at any distance from the center of the
core are then measured by drawing a line radially outward from the
center mark, and measuring and marking the distance from the
center, typically in 2 mm increments. All hardness measurements
performed on 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. The hardness difference from
any predetermined location on the core is calculated as the average
surface hardness minus the hardness at the appropriate reference
point, e.g., at the center of the core for a single, solid core,
such that a core surface softer than its center will have a
negative hardness gradient and a core surface harder than its
center will have a positive hardness gradient. Hardness gradients
are disclosed more fully, for example, in U.S. patent application
Ser. No. 11/832,163, filed on Aug. 1, 2007, the entire disclosure
of which is hereby incorporated herein by reference.
EXAMPLES
[0073] It should be understood that the examples below are for
illustrative purposes only. In no manner is the present invention
limited to the specific disclosures therein.
[0074] Twelve ionomeric inner cover layer compositions according to
the present invention were prepared by melt blending Surlyn.RTM.
8150 and Fusabond.RTM. 572D in a twin screw extruder, at a
temperature of at least 450.degree. F. (230.degree. C.). The
relative amounts of each component used are indicated in Table
1.
[0075] Flex bars of each blend composition were formed and
evaluated for hardness according to ASTM D2240 following 10 days of
aging at 50% relative humidity and 23.degree. C. The results are
reported in Table 1.
TABLE-US-00001 TABLE 1 Fusabond .RTM. Shore C Surlyn .RTM. 8150,
572D, Hardness at Example wt % wt % 10 Days 1 89 11 91.2 2 84 16
89.8 3 84 16 90.4 4 84 16 89.6 5 81 19 88.9 6 80 20 89.1 7 78 22
88.1 8 76 24 87.6 9 76 24 87.2 10 73 27 86.6 11 71 29 86.7 12 67 33
84.0
[0076] When numerical lower limits and numerical upper limits are
set forth herein, it is contemplated that any combination of these
values may be used.
[0077] All patents, publications, test procedures, and other
references cited herein, including priority documents, are fully
incorporated by reference to the extent such disclosure is not
inconsistent with this invention and for all jurisdictions in which
such incorporation is permitted.
[0078] While the illustrative embodiments of the invention have
been described with particularity, it will be understood that
various other modifications will be apparent to and can be readily
made by those of ordinary skill in the art without departing from
the spirit and scope of the invention. Accordingly, it is not
intended that the scope of the claims appended hereto be limited to
the examples and descriptions set forth herein, but rather that the
claims be construed as encompassing all of the features of
patentable novelty which reside in the present invention, including
all features which would be treated as equivalents thereof by those
of ordinary skill in the art to which the invention pertains.
* * * * *