U.S. patent application number 14/525265 was filed with the patent office on 2015-02-12 for golf ball having a thermosetting intermediate and outer cover and a thermoplastic inner cover.
This patent application is currently assigned to Acushnet Company. The applicant listed for this patent is Acushnet Company. Invention is credited to Brian Comeau, Michael Michalewich, Shawn Ricci, Michael J. Sullivan.
Application Number | 20150045149 14/525265 |
Document ID | / |
Family ID | 52449118 |
Filed Date | 2015-02-12 |
United States Patent
Application |
20150045149 |
Kind Code |
A1 |
Sullivan; Michael J. ; et
al. |
February 12, 2015 |
GOLF BALL HAVING A THERMOSETTING INTERMEDIATE AND OUTER COVER AND A
THERMOPLASTIC INNER COVER
Abstract
A golf ball includes a core and a three-layer cover disposed
about the core. The cover includes a thermoplastic inner cover
layer having a hardness of about 66 to 90 Shore C; an outer cover
layer formed from a polyurethane, a polyurea, or a hybrid thereof,
and an intermediate cover layer disposed between the inner and
outer cover layers. The outer cover layer has a hardness of about
52 to 85 Shore C. The intermediate cover layer has a hardness of
about 74 to 100 Shore C and greater than the inner cover layer
hardness and the outer cover layer hardness. The thermoplastic
inner cover comprises a highly-neutralized ionomer comprising a
copolymer of ethylene and an .alpha.,.beta.-unsaturated carboxylic
acid, an organic acid or salt thereof, and sufficient cation source
to neutralize the acid groups of the copolymer by about 100%.
Inventors: |
Sullivan; Michael J.; (Old
Lyme, CT) ; Comeau; Brian; (Berkley, MA) ;
Michalewich; Michael; (Norton, MA) ; Ricci;
Shawn; (New Bedford, MA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Acushnet Company |
Fairhaven |
MA |
US |
|
|
Assignee: |
Acushnet Company
Fairhaven
MA
|
Family ID: |
52449118 |
Appl. No.: |
14/525265 |
Filed: |
October 28, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
13965305 |
Aug 13, 2013 |
8870685 |
|
|
14525265 |
|
|
|
|
12412491 |
Mar 27, 2009 |
8506424 |
|
|
13965305 |
|
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|
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Current U.S.
Class: |
473/373 |
Current CPC
Class: |
A63B 37/0076 20130101;
A63B 37/0031 20130101; A63B 37/0024 20130101; A63B 37/0039
20130101; A63B 37/0045 20130101; C09D 123/0876 20130101; A63B
37/0092 20130101; C08L 71/00 20130101; A63B 37/0027 20130101; A63B
37/0033 20130101; A63B 37/0043 20130101 |
Class at
Publication: |
473/373 |
International
Class: |
A63B 37/00 20060101
A63B037/00 |
Claims
1. A golf ball comprising: a core; and a cover disposed adjacent
the core, the cover comprising: a thermoplastic inner cover layer
disposed about the core and having a hardness of about 66 Shore C
to about 90 Shore C; an outer cover layer comprising a
polyurethane, a polyurea, or a urethane-urea hybrid, the outer
cover layer having a hardness of about 52 Shore C to about 85 Shore
C; and an intermediate cover layer disposed between the inner and
outer cover layers, the intermediate cover layer having a hardness
of about 74 Shore C to about 100 Shore C and being greater than the
inner cover layer hardness and the outer cover layer hardness;
wherein the thermoplastic inner cover comprises a
highly-neutralized ionomer comprising a copolymer of ethylene and
an .alpha.,.beta.-unsaturated carboxylic acid, an organic acid or
salt thereof, and sufficient cation source to neutralize the acid
groups of the copolymer by 80% or greater.
2. The golf ball of claim 1, wherein the intermediate layer
hardness is greater than the inner cover layer hardness and greater
than the outer cover layer hardness by at least 5 Shore C.
3. The golf ball of claim 2, wherein the intermediate layer
hardness is greater than the inner cover layer hardness and greater
than the outer cover layer hardness by at least 10 Shore C.
4. The golf ball of claim 1, wherein the polyurethane, polyurea, or
urethane-urea blend is a castable thermoset or reaction injection
moldable thermoset.
5. The golf ball of claim 1, wherein the core comprises a center
and at least one outer core layer.
6. The golf ball of claim 1, wherein the center is a single solid
layer formed from a homogeneous composition.
7. The golf ball of claim 1, wherein the intermediate cover layer
comprises a thermoset polyurethane, a thermoset polyurea, or a
hybrid thereof.
8. The golf ball of claim 1, wherein the acid groups of the
copolymer are neutralized by 90% or greater.
9. The golf ball of claim 1, wherein the organic acid or salt
thereof comprises barium, lithium, sodium, zinc, bismuth, chromium,
cobalt, copper, potassium, strontium, titanium, tungsten,
magnesium, cesium, iron, nickel, silver, aluminum, tin, or calcium
salts, or salts of fatty acids.
10. The golf ball of claim 9, wherein the fatty acid salt comprises
stearic acid, behenic acid, erucic acid, oleic acid, linoelic acid
or dimerized derivatives thereof.
11. The golf ball of claim 9, wherein the organic acid or salt
thereof comprises a magnesium salt of oleic acid.
12. The golf ball of claim 1, wherein the acid copolymer further
comprises a softening comonomer.
13. The golf ball of claim 1, wherein the highly-neutralized
ionomer further comprises a second polymer component.
14. The golf ball of claim 13, wherein the second polymer component
comprises ionomeric copolymers and terpolymers, ionomer precursors,
thermoplastics, polyamides, polycarbonates, polyesters,
polyurethanes, polyureas, thermoplastic elastomers, polybutadiene
rubber, balata, grafted- or non-grafted metallocene-catalyzed
polymers, single-site polymers, high-crystalline acid polymers, or
cationic ionomers.
15. The golf ball of claim 1, wherein the outer cover comprises a
thermoplastic polyurethane and the intermediate cover layer
comprises a polyurea formed from the reaction product of a
prepolymer comprising an isocyanate and an amine-terminated PTMEG
and an amine-terminated curing agent.
16. The golf ball of claim 1, wherein the thermoplastic inner cover
layer further comprises polyolefins, metallocenes, polyesters,
polyamides, thermoplastic elastomers, copolyether-amides,
copolyether-esters, or mixtures thereof.
17. The golf ball of claim 1, wherein the outer cover layer
hardness is less than the inner cover layer hardness.
18. A golf ball comprising: a core; and a cover disposed adjacent
the core, the cover comprising: an inner cover layer disposed about
the core and having a hardness of about 66 Shore C to 90 Shore C,
the inner cover layer comprising a highly-neutralized ionomer
comprising a copolymer of ethylene and an
.alpha.,.beta.-unsaturated carboxylic acid, an organic acid or salt
thereof, and sufficient cation source to neutralize the acid groups
of the copolymer by about 100%; a castable thermoset outer cover
layer having a hardness of about 52 Shore C and 85 Shore C; and a
non-ionomeric thermosetting intermediate cover layer disposed
between the inner and outer cover layers and having a hardness of
about 74 Shore C to 100 Shore C and being greater than the inner
cover layer and the outer cover layer; wherein the inner cover
layer has a first thickness, the outer cover layer has a second
thickness, and the intermediate cover layer has a third thickness
less than the first or second thickness by at least 20%.
19. A golf ball comprising: a core; and a cover disposed adjacent
the core, the cover comprising: an inner cover layer disposed about
the core and having a hardness of about 66 Shore C to 90 Shore C,
the inner cover layer comprising a highly-neutralized ionomer
comprising a copolymer of ethylene and an
.alpha.,.beta.-unsaturated carboxylic acid, an organic acid or salt
thereof, and sufficient cation source to neutralize the acid groups
of the copolymer by about 100%; a castable thermoset polyurethane
outer cover layer having a hardness of about 52 Shore C and 85
Shore C; and a non-ionomeric thermosetting polyurethane polyurea
intermediate cover layer disposed between the inner and outer cover
layers and having a hardness greater than the inner cover layer and
the outer cover layer; wherein the inner cover layer has a first
thickness, the outer cover layer has a second thickness, and the
intermediate cover layer has a hardness of about 74 Shore C to 100
Shore C, and a third thickness less than the first or second
thickness by at least 20%.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation-in-part of co-pending
U.S. patent application Ser. No. 13/965,305, filed Aug. 13, 2013,
which is a continuation of U.S. patent application Ser. No.
12/412,491, filed Mar. 27, 2009 and now U.S. Pat. No. 8,506,424,
the disclosures of which are incorporated herein by reference.
FIELD OF THE INVENTION
[0002] This invention relates generally to golf balls, and more
specifically, to a golf ball having a cover including at least
three layers, the inner cover layer being formed from an ionomeric
material, the intermediate cover layer being formed from a hard
thermosetting polyurethane or polyurea material, and the outer
cover layer being formed from a softer thermosetting polyurea or
polyurethane material.
BACKGROUND OF THE INVENTION
[0003] The majority of golf balls commercially available today are
of a solid construction. Solid golf balls include one-piece,
two-piece, and multi-layer golf balls. One-piece golf balls are
inexpensive and easy to construct, but have limited playing
characteristics and their use is, at best, confined to the driving
range. Two-piece golf balls are generally constructed with a solid
polybutadiene core and a cover and are typically the most popular
with recreational golfers because they are very durable and provide
good distance. These golf balls are also relatively inexpensive and
easy to manufacture, but are regarded by top players as having
limited playing characteristics. Multi-layer golf balls are
comprised of a solid core and a cover, either of which may be
formed of one or more layers. These balls are regarded as having an
extended range of playing characteristics, but are more expensive
and difficult to manufacture than are one- and two-piece golf
balls.
[0004] Wound golf balls, which typically included a fluid-filled
center surrounded by a layer of tensioned elastomeric material and
a cover, were preferred for their spin and "feel" characteristics
but were more difficult and expensive to manufacture than solid
golf balls. Manufacturers are continuously striving to produce a
solid ball that concurrently includes the beneficial
characteristics of a wound ball.
[0005] Golf ball playing characteristics, such as compression,
velocity, and spin can be adjusted and optimized by manufacturers
to suit players having a wide variety of playing abilities. For
example, manufacturers can alter any or all of these properties by
changing the materials and/or the physical construction of each or
all of the various golf ball components (i.e., centers, cores,
intermediate layers, and covers). Finding the right combination of
core and layer materials and the ideal ball construction to produce
a golf ball suited for a predetermined set of performance criteria
is a challenging task.
[0006] Efforts to construct a multi-layer golf ball have generally
focused on the use of one or two cover layers formed of ionomeric
and/or polyurethane compositions. It is desirable, therefore, to
construct a golf ball formed of a urethane or urea outer cover
layer, at least two interior cover layers, and at least one core
layer, according to the present invention. In particular, it is
desired that this construction include a thermosetting,
high-hardness urethane or urea intermediate cover layer in
conjunction with a thermoplastic inner cover layer and a
thermosetting softer urea or urethane outer cover layer.
SUMMARY OF THE INVENTION
[0007] The present invention is directed to a golf ball including a
core and a cover. The cover includes a thermoplastic inner cover
layer having a hardness between 55 and 60 Shore D, an outer cover
layer having a hardness between 55 and 60 Shore D, and a
thermosetting polyurethane or polyurea intermediate cover layer
disposed between the inner and outer cover layers. The intermediate
cover layer has a hardness greater than the inner cover layer
hardness and the outer cover layer hardness. The inner cover is
formed from a partially- or fully-neutralized ionomer and the outer
cover layer is formed from a polyurethane, a polyurea, or a
urethane-urea blend.
[0008] In one embodiment, the intermediate layer hardness is
greater than the inner cover layer hardness and greater than the
outer cover layer hardness by at least 5 Shore D, more preferably
by at least 10 Shore D. The intermediate layer hardness is
typically 60 Shore D or greater, more preferably 75 Shore D or
greater, most preferably 80 Shore D to 90 Shore D.
[0009] The polyurethane, polyurea, or urethane-urea blend of the
outer cover layer is typically a castable thermoset or reaction
injection moldable thermoset. In a preferred embodiment, the outer
cover is formed from a castable thermoset polyurea, the inner cover
layer is formed from an ionomer blend of two or more ionomers
having differing metal cations, and the intermediate cover layer is
formed from a thermosetting polyurea.
[0010] In one ball construction, the core is a dual core having a
center and at least one outer core layer. Preferably, the center is
a solid layer formed from a single homogeneous composition. The
non-ionomeric thermoplastic polyurethane or polyurea intermediate
layer may further include a polyolefin, a polyamide, or an
acrylonitrile-butadiene-styrene polymer. In another embodiment, the
outer cover is formed from a thermoplastic polyurethane, the inner
cover layer is formed from an ionomer blend of two or more ionomers
having differing metal cations, and the intermediate cover layer is
formed from a polyurea that is the reaction product of a prepolymer
including an isocyanate and an amine-terminated PTMEG, and an
amine-terminated curing agent. The thermoplastic inner cover layer
may further include polyolefins, metallocenes, polyesters,
polyamides, thermoplastic elastomers, copolyether-amides,
copolyether-esters, or mixtures thereof.
[0011] A combination of the inner cover, the intermediate cover,
and the outer cover should have a total thickness of 0.125 inches
or less, more preferably 0.115 inches or less. It is preferred that
the outer cover layer hardness be less than the inner cover layer
hardness.
[0012] The present invention is also directed to a golf ball
including a core and a cover disposed about the core. The cover
includes an ionomeric thermoplastic inner cover layer having a
hardness of 55 Shore D to 60 Shore D, a castable thermoset outer
cover layer having a hardness between 55 Shore D and 60 Shore D,
and a non-ionomeric thermosetting intermediate cover layer disposed
between the inner and outer cover layers and having a hardness
greater than the inner cover layer and the outer cover layer. The
inner cover layer has a first thickness, the outer cover layer has
a second thickness, and the intermediate cover layer has a third
thickness less than the first or second thickness by at least
20%.
[0013] The present invention is further directed to a golf ball
including a core and a cover. The cover includes an ionomeric
thermoplastic inner cover layer disposed having a hardness of 55
Shore D to 60 Shore D, a castable thermoset polyurethane outer
cover layer having a hardness between 55 Shore D and 60 Shore D,
and a non-ionomeric thermosetting polyurethane polyurea
intermediate cover layer disposed between the inner and outer cover
layers and having a hardness greater than the inner cover layer and
the outer cover layer. The inner cover layer has a first thickness,
the outer cover layer has a second thickness, and the intermediate
cover layer has a third thickness less than the first or second
thickness by at least 20%. Preferably, the intermediate layer
hardness is greater than 60 Shore D, more preferably greater than
75 Shore D.
[0014] The present invention is directed to a golf ball including a
core and a three-layer cover disposed about the core. The cover
includes a thermoplastic inner cover layer having a hardness of
about 66 to 90 Shore C; an outer cover layer formed from a
polyurethane, a polyurea, or a hybrid thereof, and an intermediate
cover layer disposed between the inner and outer cover layers. The
outer cover layer has a hardness of about 52 to 85 Shore C. The
intermediate cover layer has a hardness of about 74 to 100 Shore C
and greater than the inner cover layer hardness and the outer cover
layer hardness. The thermoplastic inner cover comprises a
highly-neutralized ionomer comprising a copolymer of ethylene and
an .alpha.,.beta.-unsaturated carboxylic acid, an organic acid or
salt thereof, and sufficient cation source to neutralize the acid
groups of the copolymer by about 100%.
[0015] The intermediate layer hardness can be greater than the
inner cover layer hardness and greater than the outer cover layer
hardness by at least 5 Shore C, more preferably by at least 10
Shore C. The polyurethane, polyurea, or urethane-urea blend is
preferably a castable thermoset or reaction injection moldable
thermoset.
[0016] In one embodiment, the core includes a center and at least
one outer core layer and, alternatively, the center may be a single
solid layer formed from a homogeneous composition. The intermediate
cover layer may be formed from a thermoset polyurethane, a
thermoset polyurea, or a hybrid thereof.
[0017] The acid groups of the copolymer are preferably neutralized
by 90% or greater. The organic acid or salt thereof typically
includes barium, lithium, sodium, zinc, bismuth, chromium, cobalt,
copper, potassium, strontium, titanium, tungsten, magnesium,
cesium, iron, nickel, silver, aluminum, tin, or calcium salts, or
salts of fatty acids. The fatty acid salt can include stearic acid,
behenic acid, erucic acid, oleic acid, linoelic acid or dimerized
derivatives thereof. The organic acid or salt thereof is preferably
a magnesium salt of oleic acid. The acid copolymer may further
include a softening comonomer. Alternatively, the
highly-neutralized ionomer includes a second polymer component. The
second polymer component includes ionomeric copolymers and
terpolymers, ionomer precursors, thermoplastics, polyamides,
polycarbonates, polyesters, polyurethanes, polyureas, thermoplastic
elastomers, polybutadiene rubber, balata, grafted- or non-grafted
metallocene-catalyzed polymers, single-site polymers,
high-crystalline acid polymers, or cationic ionomers.
[0018] In one embodiment, the outer cover includes a thermoplastic
polyurethane and the intermediate cover layer comprises a polyurea
formed from the reaction product of a prepolymer comprising an
isocyanate and an amine-terminated PTMEG and an amine-terminated
curing agent. The thermoplastic inner cover layer may further
include polyolefins, metallocenes, polyesters, polyamides,
thermoplastic elastomers, copolyether-amides, copolyether-esters,
or mixtures thereof. In an alternative embodiment, the outer cover
layer hardness is less than the inner cover layer hardness.
[0019] The present invention is also directed to a golf ball
comprising a core; and a cover disposed adjacent the core, the
cover comprising an inner cover layer disposed about the core and
having a hardness of about 66 Shore C to 90 Shore C, the inner
cover layer comprising a highly-neutralized ionomer comprising a
copolymer of ethylene and an .alpha.,.beta.-unsaturated carboxylic
acid, an organic acid or salt thereof, and sufficient cation source
to neutralize the acid groups of the copolymer by about 100%; a
castable thermoset outer cover layer having a hardness of about 52
Shore C and 85 Shore C; and a non-ionomeric thermosetting
intermediate cover layer disposed between the inner and outer cover
layers and having a hardness of about 74 Shore C to 100 Shore C and
being greater than the inner cover layer and the outer cover layer;
wherein the inner cover layer has a first thickness, the outer
cover layer has a second thickness, and the intermediate cover
layer has a third thickness less than the first or second thickness
by at least 20%.
[0020] The present invention is further directed to a golf ball
comprising a core; and a cover disposed adjacent the core, the
cover comprising an inner cover layer disposed about the core and
having a hardness of about 66 Shore C to 90 Shore C, the inner
cover layer comprising a highly-neutralized ionomer comprising a
copolymer of ethylene and an .alpha.,.beta.-unsaturated carboxylic
acid, an organic acid or salt thereof, and sufficient cation source
to neutralize the acid groups of the copolymer by about 100%; a
castable thermoset polyurethane outer cover layer having a hardness
of about 52 Shore C and 85 Shore C; and a non-ionomeric
thermosetting polyurethane polyurea intermediate cover layer
disposed between the inner and outer cover layers and having a
hardness greater than the inner cover layer and the outer cover
layer; wherein the inner cover layer has a first thickness, the
outer cover layer has a second thickness, and the intermediate
cover layer has a hardness of about 74 Shore C to 100 Shore C, and
a third thickness less than the first or second thickness by at
least 20%.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] These and other aspects of the present invention may be more
fully understood with reference to, but not limited by, the
following drawings.
[0022] FIG. 1 is a representative cross section of a golf ball of
the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0023] A golf ball of the present invention includes a core and a
cover comprising an outer cover and at least two inner cover
layers, such as an inner cover layer and an intermediate cover
layer disposed between the outer cover layer and the inner cover
layer. The golf ball cores of the present invention may be formed
with a variety of constructions. For example, the core may include
a plurality of layers, such as a center and an outer core layer.
The core, while preferably solid, may comprise a liquid, foam, gel,
or hollow center. The golf ball may also include a layer of
tensioned elastomeric material, for example, located between the
core and triple cover. In a preferred embodiment, the core is a
solid core.
[0024] Materials for solid cores include compositions having a base
rubber, a filler, an initiator agent, and a crosslinking agent. The
base rubber typically includes natural or synthetic rubber, such as
polybutadiene rubber. A preferred base rubber is 1,4-polybutadiene
having a cis-structure of at least 40%. Most preferably, however,
the solid core is formed of a resilient rubber-based component
comprising a high-Mooney-viscosity rubber and a crosslinking
agent.
[0025] Another suitable rubber from which to form cores of the
present invention is trans-polybutadiene. This polybutadiene isomer
is formed by converting the cis-isomer of the polybutadiene to the
trans-isomer during a molding cycle. Various combinations of
polymers, cis-to-trans catalysts, fillers, crosslinkers, and a
source of free radicals, may be used. A variety of methods and
materials for performing the cis-to-trans conversion have been
disclosed in U.S. Pat. Nos. 6,162,135; 6,465,578; 6,291,592; and
6,458,895, each of which are incorporated herein, in their
entirety, by reference.
[0026] Additionally, without wishing to be bound by any particular
theory, it is believed that a low amount of 1,2-polybutadiene
isomer ("vinyl-polybutadiene") is preferable in the initial
polybutadiene to be converted to the trans-isomer. Typically, the
vinyl polybutadiene isomer content is less than about 7 percent,
more preferably less than about 4 percent, and most preferably,
less than about 2 percent.
[0027] Fillers added to one or more portions of the golf ball
typically include processing aids or compounds to affect
rheological and mixing properties, the specific gravity (i.e.,
density-modifying fillers), the modulus, the tear strength,
reinforcement, and the like. The fillers are generally inorganic,
and suitable fillers include numerous metals or metal oxides, such
as zinc oxide and tin oxide, as well as barium sulfate, zinc
sulfate, calcium carbonate, barium carbonate, clay, tungsten,
tungsten carbide, an array of silicas, and mixtures thereof.
Fillers may also include various foaming agents or blowing agents,
zinc carbonate, regrind (recycled core material typically ground to
about 30 mesh or less particle size), high-Mooney-viscosity rubber
regrind, and the like. Polymeric, ceramic, metal, and glass
microspheres may be solid or hollow, and filled or unfilled.
Fillers are typically also added to one or more portions of the
golf ball to modify the density thereof to conform to uniform golf
ball standards. Fillers may also be used to modify the weight of
the center or any or all core and cover layers, if present.
[0028] The initiator agent can be any known polymerization
initiator which decomposes during the cure cycle. Suitable
initiators include peroxide compounds such as dicumyl peroxide,
1,1-di(t-butylperoxy) 3,3,5-trimethyl cyclohexane, a-a
bis(t-butylperoxy)diisopropylbenzene, 2,5-dimethyl-2,5
di(t-butylperoxy)hexane or di-t-butyl peroxide and mixtures
thereof.
[0029] Crosslinkers are included to increase the hardness and
resilience of the reaction product. The crosslinking agent includes
a metal salt of an unsaturated fatty acid such as a zinc salt or a
magnesium salt of an unsaturated fatty acid having 3 to 8 carbon
atoms such as acrylic or methacrylic acid. Suitable cross linking
agents include metal salt diacrylates, dimethacrylates and
monomethacrylates wherein the metal is magnesium, calcium, zinc,
aluminum, sodium, lithium or nickel. Preferred acrylates include
zinc acrylate, zinc diacrylate, zinc methacrylate, and zinc
dimethacrylate, and mixtures thereof.
[0030] The crosslinking agent must be present in an amount
sufficient to crosslink a portion of the chains of polymers in the
resilient polymer component. This may be achieved, for example, by
altering the type and amount of crosslinking agent, a method
well-known to those of ordinary skill in the art.
[0031] When the core is formed of a single solid layer comprising a
high-Mooney-viscosity rubber, the crosslinking agent is present in
an amount from about 15 to about 40 parts per hundred, more
preferably from about 30 to about 38 parts per hundred, and most
preferably about 37 parts per hundred.
[0032] In another embodiment of the present invention, the core
comprises a solid center and at least one outer core layer. When
the optional outer core layer is present, the center preferably
comprises a high-Mooney-viscosity rubber and a crosslinking agent
present in an amount from about 10 to about 30 parts per hundred of
the rubber, preferably from about 19 to about 25 parts per hundred
of the rubber, and most preferably from about 20 to 24 parts
crosslinking agent per hundred of rubber. Suitable
commercially-available polybutadiene rubbers include, but are not
limited to, CB23, CB22, TAKTENE.RTM. 220, and TAKTENE.RTM. 221,
from Lanxess Corp.; NEODENE.RTM. 40 and NEODENE.RTM. 45 from
Karbochem Ltd.; LG1208 from LG Corp. of Korea; and CISSAMER.RTM.
1220 from Basstech Corp. of India. Other rubbers, such as butyl
rubber, chloro or bromyl butyl rubber, styrene butadiene rubber, or
trans polyisoprene may be added to the polybutadiene for property
or processing modification.
[0033] Additionally, the unvulcanized rubber, such as
polybutadiene, typically has a Mooney viscosity of between about 40
and about 80, more preferably, between about 40 and about 60, and
most preferably, between about 40 and about 55. Mooney viscosity is
typically measured according to ASTM D-1646.
[0034] The polymers, free-radical initiators, filler, crosslinking
agents, and any other materials used in forming either the golf
ball center or any portion of the core, in accordance with
invention, may be combined to form a mixture by any type of mixing
known to one of ordinary skill in the art. Suitable types of mixing
include single pass and multi-pass mixing, and the like. The
crosslinking agent, and any other optional additives used to modify
the characteristics of the golf ball center or additional layer(s),
may similarly be combined by any type of mixing. A single-pass
mixing process where ingredients are added sequentially is
preferred, as this type of mixing tends to increase efficiency and
reduce costs for the process. The preferred mixing cycle is single
step wherein the polymer, cis-to-trans catalyst, filler, zinc
diacrylate, and peroxide are added sequentially.
[0035] Referring to FIG. 1, in one embodiment of the present
invention the golf ball 10 includes a core 12, an inner cover layer
14, an intermediate layer 16, and an outer cover layer 18.
[0036] The cover of the golf ball is a multi-layer cover,
preferably comprised of at least three layers, such as an inner
cover layer, an intermediate cover layer, and an outer cover layer.
While the various cover layers of the present invention may be of
any individual thickness, it is preferred that the combination of
cover layer thicknesses be no greater than about 0.125 inches, more
preferably, no greater than about 0.105 inches, and most
preferably, no greater than about 0.09 inches.
[0037] Any one of the at least three cover layers preferably has a
thickness of less than about 0.05 inches, and more preferably,
between about 0.010 inches and about 0.045 inches. Most preferably,
the thickness of any one of the layers is between about 0.02 inches
and about 0.04 inches.
[0038] The inner cover can include any materials known to those of
ordinary skill in the art, including thermoplastic and
thermosetting materials, but preferably include thermoplastic ionic
copolymers of ethylene and an unsaturated monocarboxylic acid, such
as SURLYN.RTM., commercially-available from DuPont, of Wilmington,
Del., and IOTEK.RTM. or ESCOR.RTM., commercially-available from.
Exxon. These are copolymers or terpolymers of ethylene and
methacrylic acid or acrylic acid partially neutralized with salts
of zinc, sodium, lithium, magnesium, potassium, calcium, manganese,
nickel or the like, in which the salts are the reaction product of
an olefin having from 2 to 8 carbon atoms and an unsaturated
monocarboxylic acid having 3 to 8 carbon atoms. The carboxylic acid
groups of the copolymer may be totally or partially neutralized and
might include methacrylic, crotonic, maleic, fumaric or itaconic
acid.
[0039] The inner cover materials of this invention can likewise be
blended with homopolymeric and copolymer materials such as: (1)
vinyl resins, such as those formed by the polymerization of vinyl
chloride, or by the copolymerization of vinyl chloride with vinyl
acetate, acrylic esters or vinylidene chloride; (2) polyolefins,
such as polyethylene, polypropylene, polybutylene and copolymers,
such as ethylene methylacrylate, ethylene ethylacrylate, ethylene
vinyl acetate, ethylene methacrylic or ethylene acrylic acid or
propylene acrylic acid and copolymers and homopolymers produced
using a single-site catalyst; (3) non-elastic thermoplastics
including polyesters and polyamides, such as poly(hexamethylene
adipamide) and others prepared from diamines and dibasic acids, as
well as those from amino acids such as poly(caprolactam);
non-elastic thermoplastics, including polyethylene terephthalate,
polybutylene terephthalate, polyethylene terephthalate/glycol,
polyphenylene oxide resins; and blends of non-elastic
thermoplastics with Surlyn.RTM., polyethylene, ethylene copolymers,
ethylene-propylene diene terpolymer, etc.; (4) thermoplastic
rubbers, such as olefinic thermoplastic rubbers including blends of
polyolefins with ethylene-propylene diene terpolymer; (5)
thermoplastic elastomers, including block copolymers of styrene and
butadiene, or isoprene or ethylene-butylene rubber,
copoly(ether-amides), such as Pebax.RTM. sold by Elf-Atochem,
copoly(ether-ester) block copolymer elastomers sold as Hytrel.RTM.
from DuPont and Lomod.RTM. from General Electric; (6) saponified
polymers and blends thereof, including saponified polymers obtained
by reacting copolymers or terpolymers having a first monomeric
component having olefinic monomer from 2 to 8 carbon atoms, a
second monomeric component comprising an unsaturated carboxylic
acid based acrylate class ester having from 4 to 22 carbon atoms,
and an optional third monomeric component comprising at least one
monomer, such as carbon monoxide, sulfur dioxide, an anhydride, a
glycidyl group and a vinyl ester with sufficient amount of an
inorganic metal base; (7) co- and terpolymers containing glycidyl
alkyl acrylate and maleic anhydride groups, including glycidyl
alkyl acrylate and maleic anhydride groups with a first monomeric
component having olefinic monomer from 2 to 8 carbon atoms, a
second monomeric component comprising an unsaturated carboxylic
acid based acrylate class ester having from 4 to 22 carbon atoms,
and an optional third monomeric component comprising at least one
monomer selected from the group consisting of carbon monoxide,
sulfur dioxide, an anhydride, a glycidyl group and a vinyl ester;
(8) high-crystalline acid copolymers and their ionomers, including
acid copolymers or ionomer derivatives formed from an ethylene and
carboxylic acid copolymer comprising about 5 to 35 wt % acrylic or
methacrylic acid, wherein the copolymer is polymerized at a
temperature of about 130.degree. C. to 200.degree. C. and a
pressure of about 20,000 psi to 50,000 psi and wherein up to about
70% of the acid groups are neutralized with a metal ion; and (9)
oxa acid compounds including those containing oxa moiety in the
backbone having the formula:
##STR00001##
where R is an organic moiety comprising moieties having the
formula:
##STR00002##
and alkyl, carbocyclic and heterocyclic groups; R' is an organic
moiety comprising alkyl, carbocyclic, carboxylic acid, and
heterocyclic groups; and n is an integer greater than 1. Also, R'
can have the formula:
##STR00003##
[0040] Preferably, the inner cover layers are comprised of polymers
such as ethylene, propylene, butene-1 or hexane-1 based
homopolymers and copolymers including functional monomers such as
acrylic and methacrylic acid and fully or partially neutralized
ionomer resins and their blends, methyl acrylate, methyl
methacrylate homopolymers and copolymers, imidized, amino group
containing polymers, polycarbonate, reinforced polyamides,
polyphenylene oxide, high impact polystyrene, polyether ketone,
polysulfone, poly(phenylene sulfide), acrylonitrile-butadiene,
acrylic-styrene-acrylonitrile, poly(ethylene terephthalate),
poly(butylene terephthalate), poly(ethylene vinyl alcohol),
poly(tetrafluoroethylene) and their copolymers including functional
comonomers and blends thereof. Still further, the inner cover layer
is preferably comprised of a polyether or polyester thermoplastic
urethane, a thermoset polyurethane, an ionomer such as
acid-containing ethylene copolymer ionomers, including E/X/Y
copolymers where E is ethylene, X is an acrylate or
methacrylate-based softening comonomer present in 0-50 weight
percent and Y is acrylic or methacrylic acid present in 5-35 weight
percent. The acrylic or methacrylic acid is present in an amount of
about 16-35 wt %, making the ionomer a high modulus ionomer, in an
amount of about 10-12 wt %, making the ionomer a low modulus
ionomer, or in an amount of about 13-15 wt %, making the ionomer a
standard ionomer.
[0041] Preferably, the inner cover layers include polymers, such as
ethylene, propylene, butene-1 or hexane-1 based homopolymers or
copolymers including functional monomers, such as acrylic and
methacrylic acid and fully or partially neutralized ionomer resins
and their blends, methyl acrylate, methyl methacrylate homopolymers
and copolymers, imidized, amino group containing polymers,
polycarbonate, reinforced polyamides, polyphenylene oxide, high
impact polystyrene, polyether ketone, polysulfone, poly(phenylene
sulfide), acrylonitrile-butadiene, acrylic-styrene-acrylonitrile,
poly(ethylene terephthalate), poly(butylene terephthalate),
poly(ethelyne vinyl alcohol), poly(tetrafluoroethylene) and their
copolymers including functional comonomers, and blends thereof.
[0042] Suitable inner cover layer compositions also include a
polyether or polyester thermoplastic urethane, a thermoset
polyurethane, a low modulus ionomer, such as acid-containing
ethylene copolymer ionomers, including E/X/Y terpolymers where E is
ethylene, X is an acrylate or methacrylate-based softening
comonomer present in about 0 to 50 weight percent and Y is acrylic
or methacrylic acid present in about 5 to 35 weight percent. More
preferably, in a low spin rate embodiment designed for maximum
distance, the acrylic or methacrylic acid is present in about 16 to
35 weight percent, making the ionomer a high modulus ionomer. In a
higher spin embodiment, the inner cover layer includes an ionomer
where an acid is present in about 10 to 15 weight percent and
includes a softening comonomer.
[0043] Set forth below are particularly suitable highly-neutralized
polymer compositions for forming thermoplastic inner cover layers
(i.e., the innermost cover layer in a 3-cover layer golf ball). The
following commercially-available materials were used in the below
examples:
[0044] A-C.RTM. 5120 ethylene acrylic acid copolymer with an
acrylic acid content of 15%, A-C.RTM. 5180 ethylene acrylic acid
copolymer with an acrylic acid content of 20%, A-C.RTM. 395 high
density oxidized polyethylene homopolymer, and A-C.RTM. 575
ethylene maleic anhydride copolymer, commercially available from
Honeywell;
[0045] CB23 high-cis neodymium-catalyzed polybutadiene rubber,
commercially available from Lanxess Corporation;
[0046] CA1700 Soya fatty acid, CA1726 linoleic acid, and CA1725
conjugated linoleic acid, commercially available from Chemical
Associates; Century.RTM. 1107 highly purified isostearic acid
mixture of branched and straight-chain C18 fatty acid, commercially
available from Arizona Chemical;
[0047] Clarix.RTM. 011370-01 ethylene acrylic acid copolymer with
an acrylic acid content of 13% and Clarix.RTM. 011536-01 ethylene
acrylic acid copolymer with an acrylic acid content of 15%,
commercially available from A. Schulman Inc.; Elvaloy.RTM. AC 1224
ethylene-methyl acrylate copolymer with a methyl acrylate content
of 24 wt %, Elvaloy.RTM. AC 1335 ethylene-methyl acrylate copolymer
with a methyl acrylate content of 35 wt %, Elvaloy.RTM. AC 2116
ethylene-ethyl acrylate copolymer with an ethyl acrylate content of
16 wt %, Elvaloy.RTM. AC 3427 ethylene-butyl acrylate copolymer
having a butyl acrylate content of 27 wt %, and Elvaloy.RTM. AC
34035 ethylene-butyl acrylate copolymer having a butyl acrylate
content of 35 wt %, commercially available from E.I. Dupont de
Nemours and Company;
[0048] Escor.RTM. AT-320 ethylene acid terpolymer, commercially
available from ExxonMobil Chemical Company;
[0049] Exxelor.RTM. VA 1803 amorphous ethylene copolymer
functionalized with maleic anhydride, commercially available from
ExxonMobil Chemical Company;
[0050] Fusabond.RTM. N525 metallocene-catalyzed polyethylene,
Fusabond.RTM. N416 chemically modified ethylene elastomer,
Fusabond.RTM. C190 anhydride modified ethylene vinyl acetate
copolymer, and Fusabond.RTM. P614 functionalized polypropylene,
commercially available from E.I. Dupont de Nemours and Company;
[0051] Hytrel.RTM. 3078 very low modulus thermoplastic polyester
elastomer, commercially available from E.I. Dupont de Nemours and
Company;
[0052] Kraton.RTM. FG 1901 GT linear triblock copolymer based on
styrene and ethylene/butylene with a polystyrene content of 30% and
Kraton.RTM. FG1924GT linear triblock copolymer based on styrene and
ethylene/butylene with a polystyrene content of 13%, commercially
available from Kraton Performance Polymers Inc.;
[0053] Lotader.RTM. 4603, 4700 and 4720, random copolymers of
ethylene, acrylic ester and maleic anhydride, commercially
available from Arkema Corporation;
[0054] Nordel.RTM. IP 4770 high molecular weight semi-crystalline
EPDM rubber, commercially available from The Dow Chemical
Company;
[0055] Nucrel.RTM. 9-1, Nucrel.RTM. 599, Nucrel.RTM. 960,
Nucrel.RTM. 0407, Nucrel.RTM. 0609, Nucrel.RTM. 1214, Nucrel.RTM.
2906, Nucrel.RTM. 2940, Nucrel.RTM. 30707, Nucrel.RTM. 31001, and
Nucrel.RTM. AE acid copolymers, commercially available from E.I.
Dupont de Nemours and Company;
[0056] Primacor.RTM. 3150, 3330, 59801, and 59901 acid copolymers,
commercially available from The Dow Chemical Company;
[0057] Royaltuf.RTM. 498 maleic anhydride modified polyolefin based
on an amorphous EPDM, commercially available from Chemtura
Corporation;
[0058] Sylfat.RTM. FA2 tall oil fatty acid, commercially available
from Arizona Chemical;
[0059] Vamac.RTM. G terpolymer of ethylene, methylacrylate and a
cure site monomer, commercially available from E.I. Dupont de
Nemours and Company; and
[0060] XUS 60758.08L ethylene acrylic acid copolymer with an
acrylic acid content of 13.5%, commercially available from The Dow
Chemical Company.
[0061] Various compositions were melt blended using components as
given in Table 18 below. The compositions were neutralized by
adding a cation source in an amount sufficient to neutralize,
theoretically, 110% of the acid groups present in components 1 and
3, except for example 72, in which the cation source was added in
an amount sufficient to neutralize 75% of the acid groups.
Magnesium hydroxide was used as the cation source, except for
example 68, in which magnesium hydroxide and sodium hydroxide were
used in an equivalent ratio of 4:1. In addition to components 1-3
and the cation source, example 71 contains ethyl oleate
plasticizer.
[0062] The relative amounts of component 1 and component 2 used are
indicated in Table 18 below, and are reported in wt %, based on the
combined weight of components 1 and 2. The relative amounts of
component 3 used are indicated in Table 1 below, and are reported
in wt %, based on the total weight of the composition.
TABLE-US-00001 TABLE 1 Ex. Component 1 wt % Component 2 wt %
Component 3 wt % 1 Primacor 5980I 78 Lotader 4603 22 magnesium
oleate 41.6 2 Primacor 5980I 84 Elvaloy AC 1335 16 magnesium oleate
41.6 3 Primacor 5980I 78 Elvaloy AC 3427 22 magnesium oleate 41.6 4
Primacor 5980I 78 Elvaloy AC 1335 22 magnesium oleate 41.6 5
Primacor 5980I 78 Elvaloy AC 1224 22 maanesium oleate 41.6 6
Primacor 5980I 78 Lotader 4720 22 magnesium oleate 41.6 7 Primacor
5980I 85 Vamac G 15 magnesium oleate 41.6 8 Primacor 5980I 90 Vamac
G 10 magnesium oleate 41.6 8.1 Primacor 5990I 90 Fusabond 614 10
magnesium oleate 41.6 9 Primacor 5980I 78 Vamac G 22 magnesium
oleate 41.6 10 Primacor 5980I 75 Lotader 4720 25 magnesium oleate
41.6 11 Primacor 5980I 55 Elvaloy AC 3427 45 magnesium oleate 41.6
12 Primacor 5980I 55 Elvaloy AC 1335 45 maanesium oleate 41.6 12.1
Primacor 5980I 55 Elvaloy AC 34035 45 magnesium oleate 41.6 13
Primacor 5980I 55 Elvaloy AC 2116 45 magnesium oleate 41.6 14
Primacor 5980I 78 Elvaloy AC 34035 22 maanesium oleate 41.6 14.1
Primacor 5990I 80 Elvaloy AC 34035 20 magnesium oleate 41.6 15
Primacor 5980I 34 Elvaloy AC 34035 66 magnesium oleate 41.6 16
Primacor 5980I 58 Vamac G 42 magnesium oleate 41.6 17 Primacor
5990I 80 Fusabond 416 20 magnesium oleate 41.6 18 Primacor 5980I
100 -- -- magnesium oleate 41.6 19 Primacor 5980I 78 Fusabond 416
22 magnesium oleate 41.6 20 Primacor 5990I 100 -- -- magnesium
oleate 41.6 21 Primacor 5990I 20 Fusabond 416 80 magnesium oleate
41.6 21.1 Primacor 5990I 20 Fusabond 416 80 magnesium oleate 31.2
21.2 Primacor 5990I 20 Fusabond 416 80 magnesium oleate 20.8 22
Clarix 011370 30.7 Fusabond 416 69.3 magnesium oleate 41.6 23
Primacor 5990I 20 Royaltuf 498 80 magnesium oleate 41.6 24 Primacor
5990I 80 Royaltuf 498 20 magnesium oleate 41.6 25 Primacor 5990I 80
Kraton FG1924GT 20 magnesium oleate 41.6 26 Primacor 5990I 20
Kraton FG1924GT 80 magnesium oleate 41.6 27 Nucrel 30707 57
Fusabond 416 43 magnesium oleate 41.6 28 Primacor 5990I 80 Hytrel
3078 20 magnesium oleate 41.6 29 Primacor 5990I 20 Hytrel 3078 80
magnesium oleate 41.6 30 Primacor 5980I 26.8 Elvaloy AC 34035 73.2
magnesium oleate 41.6 31 Primacor 5980I 26.8 Lotader 4603 73.2
magnesium oleate 41.6 32 Primacor 5980I 26.8 Elvaloy AC 2116 73.2
magnesium oleate 41.6 33 Escor AT-320 30 Elvaloy AC 34035 52
magnesium oleate 41.6 Primacor 5980I 18 34 Nucrel 30707 78.5
Elvaloy AC 34035 21.5 magnesium oleate 41.6 35 Nucrel 30707 78.5
Fusabond 416 21.5 magnesium oleate 41.6 36 Primacor 5980I 26.8
Fusabond 416 73.2 magnesium oleate 41.6 37 Primacor 5980I 19.5
Fusabond N525 80.5 magnesium oleate 41.6 38 Clarix 011536-01 26.5
Fusabond N525 73.5 maanesium oleate 41.6 39 Clarix 011370-01 31
Fusabond N525 69 maanesium oleate 41.6 39.1 XUS 60758.08L 29.5
Fusabond N525 70.5 magnesium oleate 41.6 40 Nucrel 31001 42.5
Fusabond N525 57.5 magnesium oleate 41.6 41 Nucrel 30707 57.5
Fusabond N525 42.5 magnesium oleate 41.6 42 Escor AT-320 66.5
Fusabond N525 33.5 magnesium oleate 41.6 43 Nucrel 2906/2940 21
Fusabond N525 79 magnesium oleate 41.6 44 Nucrel 960 26.5 Fusabond
N525 73.5 magnesium oleate 41.6 45 Nucrel 1214 33 Fusabond N525 67
maanesium oleate 41.6 46 Nucrel 599 40 Fusabond N525 60 magnesium
oleate 41.6 47 Nucrel 9-1 44.5 Fusabond N525 55.5 magnesium oleate
41.6 48 Nucrel 0609 67 Fusabond N525 33 magnesium oleate 41.6 49
Nucrel 0407 100 -- -- magnesium oleate 41.6 50 Primacor 5980I 90
Fusabond N525 10 magnesium oleate 41.6 51 Primacor 5980I 80
Fusabond N525 20 magnesium oleate 41.6 52 Primacor 5980I 70
Fusabond N525 30 magnesium oleate 41.6 53 Primacor 5980I 60
Fusabond N525 40 magnesium oleate 41.6 54 Primacor 5980I 50
Fusabond N525 50 magnesium oleate 41.6 55 Primacor 5980I 40
Fusabond N525 60 magnesium oleate 41.6 56 Primacor 5980I 30
Fusabond N525 70 magnesium oleate 41.6 57 Primacor 5980I 20
Fusabond N525 80 magnesium oleate 41.6 58 Primacor 5980I 10
Fusabond N525 90 magnesium oleate 41.6 59 -- -- Fusabond N525 100
magnesium oleate 41.6 60 Nucrel 0609 40 Fusabond N525 20 magnesium
oleate 41.6 Nucrel 0407 40 61 Nucrel AE 100 -- -- magnesium oleate
41.6 62 Primacor 5980I 30 Fusabond N525 70 CA1700 soya fatty 41.6
acid magnesium salt 63 Primacor 5980I 30 Fusabond N525 70 CA1726
linoleic acid 41.6 magnesium salt 64 Primacor 5980I 30 Fusabond
N525 70 CA1725 conjugated 41.6 linoleic acid magnesium salt 65
Primacor 5980I 30 Fusabond N525 70 Century 1107 41.6 isostearic
acid magnesium salt 66 A-C 5120 73.3 Lotader 4700 26.7 magnesium
oleate 41.6 67 A-C 5120 73.3 Elvaloy 34035 26.7 magnesium oleate
41.6 68 Primacor 5980I 78.3 Lotader 4700 21.7 magnesium oleate 41.6
and sodium salt 69 Primacor 5980I 47 Elvaloy AC34035 13 -- -- A-C
5180 40 70 Primacor 5980I 30 Fusabond N525 70 Sylfat FA2 41.6
magnesium salt 71 Primacor 5980I 30 Fusabond N525 70 magnesium
oleate 31.2 ethyl oleate 10 72 Primacor 5980I 80 Fusabond N525 20
sebacic acid 41.6 magnesium salt 73 Primacor 5980I 60 -- -- -- --
A-C5180 40 74 Primacor 5980I 78.3 -- -- magnesium oleate 41.6 A-C
575 21.7 75 Primacor 5980I 78.3 Exxelor VA 1803 21.7 magnesium
oleate 41.6 76 Primacor 5980I 78.3 A-C 395 21.7 magnesium oleate
41.6 77 Primacor 5980I 78.3 Fusabond C190 21.7 maanesium oleate
41.6 78 Primacor 5980I 30 Kraton FG 1901 70 magnesium oleate 41.6
79 Primacor 5980I 30 Royaltuf 498 70 magnesium oleate 41.6 80 A-C
5120 40 Fusabond N525 60 magnesium oleate 41.6 81 Primacor 5980I 30
Fusabond N525 70 erucic acid 41.6 magnesium salt 82 Primacor 5980I
30 CB23 70 maanesium oleate 41.6 83 Primacor 5980I 30 Nordel IP
4770 70 magnesium oleate 41.6 84 Primacor 5980I 48 Fusabond N525 20
magnesium oleate 41.6 A-C5180 32 85 Nucrel 2806 22.2 Fusabond N525
77.8 magnesium oleate 41.6 86 Primacor 3330 61.5 Fusabond N525 38.5
magnesium oleate 41.6 87 Primacor 3330 45.5 Fusabond N525 20
magnesium oleate 41.6 Primacor 3150 34.5 88 Primacor 3330 28.5 --
-- magnesium oleate 41.6 Primacor 3150 71.5 89 Primacor 3150 67
Fusabond N525 33 maanesium oleate 41.6 90 Primacor 5980I 55 Elvaloy
AC 34035 45 magnesium oleate lt 31.2 ethyl oleate 10
[0063] Solid spheres of each composition were injection molded, and
the solid sphere COR, compression, Shore D hardness, and Shore C
hardness of the resulting spheres were measured after two weeks.
The results are reported in Table 2 below.
TABLE-US-00002 TABLE 2 Solid Sphere Solid Sphere Solid Sphere Solid
Sphere Ex. COR Compression Shore D Shore C 1 0.845 120 59.6 89.2 3
0.871 117 57.7 88.6 4 0.867 122 63.7 90.6 5 0.866 119 62.8 89.9 8.1
0.869 127 65.3 92.9 12 0.856 101 55.7 82.4 12.1 0.857 105 53.2 81.3
14 0.873 122 64.0 91.1 17 0.878 117 60.1 89.4 18 0.853 135 67.6
94.9 20 0.857 131 66.2 94.4 21 0.752 26 34.8 57.1 21.1 0.729 9 34.3
56.3 21.2 0.720 2 33.8 55.2 30 ** 66 42.7 65.5 31 0.730 67 45.6
68.8 32 ** 100 52.4 78.2 33 0.760 64 43.6 64.5 34 0.814 91 52.8
80.4 51 0.873 121 61.5 90.2 52 0.870 116 60.4 88.2 53 0.865 107
57.7 84.4 54 0.853 97 53.9 80.2 55 0.837 82 50.1 75.5 56 0.818 66
45.6 70.7 57 0.787 45 41.3 64.7 58 0.768 26 35.9 57.3 ** sphere
broke during measurement
[0064] While the inventive golf ball may be formed from a variety
of differing intermediate and outer cover materials, preferred
materials include, but are not limited to, (1) polyurethanes, such
as those prepared from polyols or polyamines and diisocyanates or
polyisocyanates and/or their prepolymers, and those disclosed in
U.S. Pat. Nos. 5,334,673 and 6,506,851; (2) polyureas, such as
those disclosed in U.S. Pat. Nos. 5,484,870 and 6,835,794; (3)
polyurethane-urea hybrids, blends or copolymers comprising urethane
or urea segments; and (4) other suitable polyurethane compositions
comprising a reaction product of at least one polyisocyanate and at
least one curing agent are disclosed in U.S. Pat. Nos. 7,105,610
and 7,491,787, all of which are incorporated herein by
reference.
[0065] In a preferred embodiment, the golf balls of the invention
include an intermediate cover layer formed from a thermosetting,
high hardness polyurethane or polyurea composition and the outer
cover layer is formed from a thermosetting urethane or urea having
a hardness less than the intermediate layer.
[0066] Suitable polyurethane compositions comprise a reaction
product of at least one isocyanate and at least one curing agent.
The curing agent can include, for example, one or more polyols or a
combination thereof. The isocyanate can be combined with one or
more polyols to form a prepolymer, which is then combined with the
at least one curing agent (also known as a chain extender). 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. Polyurethanes are also
described in terms of "hard segment" and "soft segment." The
isocyanate component of the prepolymer along with the chain
extender (curing agent) are collectively designated the "hard
segment" and the remaining polyol component of the prepolymer is
designated the "soft segment."
[0067] The hardness of polyurethanes and polyureas can be
controlled by a number of different methods. One such method
involves changing the ratio of "hard segment" to "soft segment." As
the ratio of hard segment to soft segment increases, the hardness
of the resulting polyurethane increases accordingly. Conversely, as
the ratio of hard segment to soft segment decreases, the hardness
of the resulting polyurethane decreases. Changing the ratio of hard
segment to soft segment can be achieved by increasing or decreasing
the amount of diisocyanate and/or chain extender while keeping the
amount of soft segment constant. Typically, this is done by
increasing/decreasing the percent of isocyanate in the
prepolymer.
[0068] A similar effect on hardness may be achieved by varying the
molecular weight of the soft segment. For example, using a soft
segment having a lower molecular weight will generally result in a
polyurethane having a higher hardness compared to a polyurethane in
which a higher molecular weight soft segment was used.
[0069] Another method of changing the hardness of a polyurethane or
polyurea material is by changing the crosslink density of the
material. Hardness of the resultant material may be increased by
increasing the crosslink density and decreased by decreasing the
crosslink density. Additionally, making use of di-, tri-, and
tetra-functional materials may also enable one to increase or
decrease hardness as desired. Soft segment functionality has some
effect on resulting hardness, however, a greater effect is obtained
by changing the functionality of either the isocyanate or chain
extender. Crosslink density may also be increased through the use
of a dual cure system, where an unsaturated polyurethane or
polyurea is reacted, followed by a free radical reaction (i.e.,
peroxide or UV), to create crosslinks at sites of unsaturation.
[0070] Because crosslinking in castable reactive liquid materials
is limited to hard segments, the ability to increase crosslinking
density and, therefore, hardness, is limited. As such, other
polyurethanes (and polyureas) suitable for the layers of the
present invention include a prepolymer that is a reaction product
of an isocyanate-containing component and an isocyanate-reactive
component that are subjected to a curing process that involves a
first curative that crosslinks the hard segments in the polymer and
a second curative that crosslinks the soft segments (i.e.,
crosslinked with a combination of a curing agent and a free radical
initiator). Examples of dual cure systems are disclosed in U.S.
patent application Ser. No. 12/122,333, the disclosure of which is
incorporated herein in its entirety by reference.
[0071] The intermediate layers of the invention are harder than the
outer cover layers and make use of the above methods to change the
properties of the respective layer materials despite them being of
the same broad class, i.e., polyurethanes or polyureas. The
intermediate layer formulation and cover layer formulation may be
based on the same raw materials but can be designed to have
different hardness values. For example, the intermediate layer may
consist of an MDI/PTMEG prepolymer at an NCO level of 8% which is
chain extended with dimethylthiotoluenediamine to produce a
polyurethane having a hardness of 64 Shore D. Similarly, the outer
cover layer may also be based on an MDI/PTMEG prepolymer at an NCO
level of 6% which is chain extended with dimethylthiotoluenediamine
resulting in a cover layer that has a hardness of 45 Shore D,
significantly softer than the intermediate layer. Alternatively,
6.5% NCO would result in a hardness of 48 Shore D, 9.0% NCO being
65.5 Shore D; and 10.0% NCO being 66.5 Shore D.
[0072] Exemplary polyisocyanates suitable for use in the outer
cover layers of the invention include, but are not limited to,
4,4'-diphenylmethane diisocyanate (MDI); polymeric MDI;
carbodiimide-modified liquid MDI; 4,4'-dicyclohexylmethane
diisocyanate (H.sub.12MDI); p-phenylene diisocyanate (PPDI);
m-phenylene diisocyanate (MPDI); toluene diisocyanate (TDI);
3,3'-dimethyl-4,4'-biphenylene diisocyanate;
isophoronediisocyanate; 1,6-hexamethylene diisocyanate (HDI);
naphthalene diisocyanate; xylene diisocyanate; p-tetramethylxylene
diisocyanate; m-tetramethylxylene diisocyanate; ethylene
diisocyanate; propylene-1,2-diisocyanate;
tetramethylene-1,4-diisocyanate; cyclohexyl diisocyanate;
dodecane-1,12-diisocyanate; cyclobutane-1,3-diisocyanate;
cyclohexane-1,3-diisocyanate; cyclohexane-1,4-diisocyanate;
1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane; methyl
cyclohexylene diisocyanate; triisocyanate of HDI; triisocyanate of
2,4,4-trimethyl-1,6-hexane diisocyanate; tetracene diisocyanate;
napthalene diisocyanate; anthracene diisocyanate; isocyanurate of
toluene diisocyanate; uretdione of hexamethylene diisocyanate; and
mixtures thereof. Polyisocyanates are known to those of ordinary
skill in the art as having more than one isocyanate group, e.g.,
di-isocyanate, tri-isocyanate, and tetra-isocyanate. Preferably,
the polyisocyanate includes MDI, PPDI, TDI, or a mixture thereof,
and more preferably, the polyisocyanate includes MDI. It should be
understood that, as used herein, the term MDI includes
4,4'-diphenylmethane diisocyanate, polymeric MDI,
carbodiimide-modified liquid MDI, and mixtures thereof and,
additionally, that the diisocyanate employed may be "low free
monomer," understood by one of ordinary skill in the art to have
lower levels of "free" monomer isocyanate groups, typically less
than about 0.1% free monomer isocyanate groups. Examples of "low
free monomer" diisocyanates include, but are not limited to Low
Free Monomer MDI, Low Free Monomer TDI, and Low Free Monomer
PPDI.
[0073] The at least one polyisocyanate should have less than about
14% unreacted NCO groups. Preferably, the at least one
polyisocyanate has no greater than about 8.0% NCO, more preferably
no greater than about 7.8%, and most preferably no greater than
about 7.5% NCO with a level of NCO of about 7.2 or 7.0, or 6.5% NCO
commonly used.
[0074] 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.
[0075] 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.
[0076] 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.
[0077] 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.
[0078] 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.
[0079] 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; polypropylene glycol; lower molecular weight
polytetramethylene ether glycol; 1,3-bis(2-hydroxyethoxy)benzene;
1,3-bis-[2-(2-hydroxyethoxy)ethoxy]benzene;
1,3-bis-{2-[2-(2-hydroxyethoxy)ethoxy]ethoxy}benzene;
1,4-butanediol; 1,5-pentanediol; 1,6-hexanediol;
resorcinol-di-(.beta.-hydroxyethyl)ether;
hydroquinone-di-(.beta.-hydroxyethyl) ether; and mixtures thereof.
Preferred hydroxy-terminated curatives include
1,3-bis(2-hydroxyethoxy)benzene;
1,3-bis-[2-(2-hydroxyethoxy)ethoxy]benzene;
1,3-bis-{2-[2-(2-hydroxyethoxy)ethoxy]ethoxy}benzene;
1,4-butanediol, and mixtures thereof. Preferably, the
hydroxy-terminated curatives have molecular weights ranging from
about 48 to 2000. It should be understood that molecular weight, as
used herein, is the absolute weight average molecular weight and
would be understood as such by one of ordinary skill in the
art.
[0080] Both the hydroxy-terminated and amine curatives can include
one or more saturated, unsaturated, aromatic, and cyclic groups.
Additionally, the hydroxy-terminated and amine curatives can
include one or more halogen groups. The polyurethane composition
can be formed with a blend or mixture of curing agents. If desired,
however, the polyurethane composition may be formed with a single
curing agent.
[0081] In a preferred embodiment of the present invention,
saturated polyurethanes are used to form one or more of the cover
layers, preferably the outer cover layer, and may be selected from
among both castable thermoset and thermoplastic polyurethanes.
[0082] In this embodiment, the saturated polyurethanes of the
present invention are substantially free of aromatic groups or
moieties. Saturated polyurethanes suitable for use in the invention
are a product of a reaction between at least one polyurethane
prepolymer and at least one saturated curing agent. The
polyurethane prepolymer is a product formed by a reaction between
at least one saturated polyol and at least one saturated
diisocyanate. As is well known in the art, that a catalyst may be
employed to promote the reaction between the curing agent and the
isocyanate and polyol, or the curing agent and the prepolymer.
[0083] Saturated diisocyanates which can be used include, without
limitation, ethylene diisocyanate; propylene-1,2-diisocyanate;
tetramethylene-1,4-diisocyanate; 1,6-hexamethylene-diisocyanate
(HDI); 2,2,4-trimethylhexamethylene diisocyanate;
2,4,4-trimethylhexamethylene diisocyanate;
dodecane-1,12-diisocyanate; dicyclohexylmethane diisocyanate;
cyclobutane-1,3-diisocyanate; cyclohexane-1,3-diisocyanate;
cyclohexane-1,4-diisocyanate;
1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane;
isophorone diisocyanate; methyl cyclohexylene diisocyanate;
triisocyanate of HDI; triisocyanate of 2,2,4-trimethyl-1,6-hexane
diisocyanate. The most preferred saturated diisocyanates are
4,4'-dicyclohexylmethane diisocyanate and isophorone
diisocyanate.
[0084] Saturated polyols which are appropriate for use in this
invention include without limitation polyether polyols such as
polytetramethylene ether glycol and poly(oxypropylene)glycol.
Suitable saturated polyester polyols include polyethylene adipate
glycol, polyethylene propylene adipate glycol, polybutylene adipate
glycol, polycarbonate polyol and ethylene oxide-capped
polyoxypropylene diols. Saturated polycaprolactone polyols which
are useful in the invention include diethylene glycol-initiated
polycaprolactone, 1,4-butanediol-initiated polycaprolactone,
1,6-hexanediol-initiated polycaprolactone; trimethylol
propane-initiated polycaprolactone, neopentyl glycol initiated
polycaprolactone, and polytetramethylene ether glycol-initiated
polycaprolactone. The most preferred saturated polyols are
polytetramethylene ether glycol and PTMEG-initiated
polycaprolactone.
[0085] Suitable saturated curatives include 1,4-butanediol,
ethylene glycol, diethylene glycol, polytetramethylene ether
glycol, propylene glycol; trimethanolpropane;
tetra-(2-hydroxypropyl)-ethylenediamine; isomers and mixtures of
isomers of cyclohexyldimethylol, isomers and mixtures of isomers of
cyclohexane bis(methylamine); triisopropanolamine; ethylene
diamine; diethylene triamine; triethylene tetramine; tetraethylene
pentamine; 4,4'-dicyclohexylmethane diamine;
2,2,4-trimethyl-1,6-hexanediamine;
2,4,4-trimethyl-1,6-hexanediamine; diethyleneglycol
di-(aminopropyl)ether;
4,4'-bis-(sec-butylamino)-dicyclohexylmethane;
1,2-bis-(sec-butylamino)cyclohexane;
1,4-bis-(sec-butylamino)cyclohexane; isophorone diamine;
hexamethylene diamine; propylene diamine; 1-methyl-2,4-cyclohexyl
diamine; 1-methyl-2,6-cyclohexyl diamine; 1,3-diaminopropane;
dimethylamino propylamine; diethylamino propylamine;
imido-bis-propylamine; isomers and mixtures of isomers of
diaminocyclohexane; monoethanolamine; diethanolamine;
triethanolamine; monoisopropanolamine; and diisopropanolamine. The
most preferred saturated curatives are 1,4-butanediol,
1,4-cyclohexyldimethylol and
4,4'-bis-(sec-butylamino)-dicyclohexylmethane.
[0086] Alternatively, other suitable polymers include partially or
fully neutralized ionomer, metallocene, or other single-site
catalyzed polymer, polyester, polyamide, non-ionomeric
thermoplastic elastomer, copolyether-esters, copolyether-amides,
polycarbonate, polybutadiene, polyisoprene, polystryrene block
copolymers (such as styrene-butadiene-styrene),
styrene-ethylene-propylene-styrene,
styrene-ethylene-butylene-styrene, and the like, and blends
thereof. Thermosetting polyurethanes or polyureas are suitable for
the outer cover layers of the golf balls of the present invention.
Other suitable polyurethanes are described in U.S. Pat. No.
7,331,878, which is incorporated by reference in its entirety.
[0087] Additionally, polyurethane can be replaced with or blended
with a polyurea material. Polyureas are distinctly different from
polyurethane compositions, but also result in desirable aerodynamic
and aesthetic characteristics when used in golf ball components.
The polyurea-based compositions are preferably saturated in
nature.
[0088] Without being bound to any particular theory, it is now
believed that substitution of the long chain polyol segment in the
polyurethane prepolymer with a long chain polyamine oligomer soft
segment to form a polyurea prepolymer, improves shear, cut, and
resiliency, as well as adhesion to other components. Thus, the
polyurea compositions of this invention may be formed from the
reaction product of an isocyanate and polyamine prepolymer
crosslinked with a curing agent. For example, polyurea-based
compositions of the invention may be prepared from at least one
isocyanate, at least one polyether amine, and at least one diol
curing agent or at least one diamine curing agent.
[0089] Any polyamine available to one of ordinary skill in the art
is suitable for use in the polyurea prepolymer. Polyether amines
are particularly suitable for use in the prepolymer. As used
herein, "polyether amines" refer to at least polyoxyalkyleneamines
containing primary amino groups attached to the terminus of a
polyether backbone. Due to the rapid reaction of isocyanate and
amine, and the insolubility of many urea products, however, the
selection of diamines and polyether amines is limited to those
allowing the successful formation of the polyurea prepolymers. In
one embodiment, the polyether backbone is based on tetramethylene,
propylene, ethylene, trimethylolpropane, glycerin, and mixtures
thereof.
[0090] Suitable polyether amines include, but are not limited to,
methyldiethanolamine; polyoxyalkylenediamines such as,
polytetramethylene ether diamines, polyoxypropylenetriamine, and
polyoxypropylene diamines; poly(ethylene oxide capped
oxypropylene)ether diamines; propylene oxide-based triamines;
triethyleneglycoldiamines; trimethylolpropane-based triamines;
glycerin-based triamines; and mixtures thereof. In one embodiment,
the polyether amine used to form the prepolymer is JEFFAMINE.RTM.
D2000 (manufactured by Huntsman Chemical Co. of Austin, Tex.).
[0091] The molecular weight of the polyether amine for use in the
polyurea prepolymer may range from about 100 to about 5000. In one
embodiment, the polyether amine molecular weight is about 200 or
greater, preferably about 230 or greater. In another embodiment,
the molecular weight of the polyether amine is about 4000 or less.
In yet another embodiment, the molecular weight of the polyether
amine is about 600 or greater. In still another embodiment, the
molecular weight of the polyether amine is about 3000 or less. In
yet another embodiment, the molecular weight of the polyether amine
is between about 1000 and about 3000, more preferably is between
about 1500 to about 2500, and most preferably from 2000 to 2500.
Because lower molecular weight polyether amines may be prone to
forming solid polyureas, a higher molecular weight oligomer, such
as JEFFAMINE.RTM. D2000, is preferred.
[0092] Other suitable castable polyurea compositions for use in the
golf balls of the present invention include those formed from the
reaction product of a prepolymer formed from an isocyanate and an
amine-terminated polytetramethylene ether glycol and an
amine-terminated curing agent, and those formed from the reaction
product of a polyurea prepolymer cured with an amine-terminated
polytetramethylene ether glycol. In either scenario, the
amine-terminated polytetramethylene ether glycol is terminated with
secondary amines. In addition, the amine-terminated
polytetramethylene ether glycol may be a copolymer with
polypropylene glycol, wherein the polytetramethylene ether glycol
is end-capped with one or more propylene glycol units to form the
copolymer.
[0093] Another suitable composition includes a prepolymer including
the reaction product of an isocyanate-containing component and an
amine-terminated component, wherein the amine-terminated component
includes a copolymer of polytetramethylene ether glycol and
polypropylene glycol including at least one terminal amino group;
and an amine-terminated curing agent. In this aspect of the
invention the prepolymer may includes about 4 percent to about 9
percent NCO groups by weight of the prepolymer.
[0094] In one embodiment, the at least one terminal amino group
includes secondary amines. In another embodiment, the at least one
terminal amino group includes a terminal secondary amino group at
both ends of the copolymer. In yet another embodiment, the
amine-terminated curing agent includes a secondary diamine.
[0095] The polyureas of the present invention also include a
polyurea composition formed from a prepolymer formed from the
reaction product of an isocyanate-containing compound and an
isocyanate-reactive compound, wherein the isocyanate-reactive
compound includes polytetramethylene ether glycol ("PTMEG")
homopolymer having a molecular weight of about 1800 to about 2200
and terminal secondary amino groups; and an amine-terminated curing
agent. In this aspect of the invention, the prepolymer may include
about 6 percent to about 8 percent NCO groups by weight of the
prepolymer. In addition, the PTMEG homopolymer may have a molecular
weight of about 1900 to about 2100. In one embodiment, the
amine-terminated curing agent includes a secondary diamine.
[0096] In one embodiment, the polyalkylene glycol includes
polypropylene glycol, polyethylene glycol, and copolymers or
mixtures thereof. In another embodiment, the amino groups include
secondary amino groups. The amine-terminated curing agent may
include an amine-terminated polytetramethylene ether glycol. In one
embodiment, the amine-terminated polytetramethylene ether glycol
includes at least one terminal secondary amino group.
[0097] Conventional aromatic polyurethane/urethane elastomers and
polyurethane/urea elastomers are generally prepared by curing a
prepolymer of diisocyanate and long chain polyol with at least one
diol curing agent or at least one diamine curing agent,
respectively. In contrast, the use of a long chain amine-terminated
compound to form a polyurea prepolymer has been shown to improve
shear, cut, and resiliency, as well as adhesion to other
components.
[0098] Without being bound to any particular theory, it has now
been discovered that the use of an amine-terminated
polytetramethylene ether glycol and/or an amine-terminated
copolymer of PTMEG and polypropylene glycol ("PPG") in the
prepolymer or as a curing agent provide enhanced shear, cut, and
resiliency as compared to conventional polyurea elastomers. For
example, the compositions of the invention have improved durability
and performance characteristics over that of a polyurea composition
formed with amine-terminated PPG.
[0099] The polyurea-based compositions of this invention may be
formed in several ways: a) from a prepolymer that is the reaction
product of an isocyanate-containing component and amine-terminated
PTMEG chain extended with a curing agent; b) from a prepolymer that
is the reaction product of an isocyanate-containing component and
an amine-terminated copolymer of PTMEG and PPG chain extended with
a curing agent; c) from a prepolymer that is the reaction product
of a polyurea-based prepolymer chain extended with an
amine-terminated PTMEG; and d) from a prepolymer that is the
reaction product of a polyurea-based prepolymer chain extended with
an amine-terminated copolymer of PTMEG and PPG.
[0100] For example, the compositions of the invention may be
prepared from at least one isocyanate-containing component, at
least one amine-terminated copolymer of PTMEG and PPG, preferably a
secondary diamine, and at least one amine-terminated curing agent,
preferably a secondary aliphatic diamine or primary aromatic
diamine curing agent. The presence of PTMEG in the backbone
provides better shear resistance as compared to a backbone
including only PPG.
[0101] Commercially-available amine-terminated PTMEG and/or
copolymer of PTMEG and PPG include those sold by Huntsman Chemical
under the tradenames XTJ-559, XTG-604, XTG-605, and XTG-653.
[0102] As briefly discussed above, some amines may be unsuitable
for reaction with the isocyanate because of the rapid reaction
between the two components. In particular, shorter chain amines are
fast reacting. In one embodiment, however, a hindered secondary
diamine may be suitable for use in the prepolymer. Without being
bound to any particular theory, it is believed that an amine with a
high level of stearic hindrance, e.g., a tertiary butyl group on
the nitrogen atom, has a slower reaction rate than an amine with no
hindrance or a low level of hindrance. For example,
4,4'-bis-(sec-butylamino)-dicyclohexylmethane (CLEARLINK.RTM. 1000)
may be suitable for use in combination with an isocyanate to form
the polyurea prepolymer.
[0103] Any isocyanate available to one of ordinary skill in the art
is suitable for use in the polyurea prepolymer. Isocyanates for use
with the present invention include aliphatic, cycloaliphatic,
araliphatic, aromatic, any derivatives thereof, and combinations of
these compounds having two or more isocyanate (NCO) groups per
molecule. The isocyanates may be organic polyisocyanate-terminated
prepolymers. The isocyanate-containing reactable component may also
include any isocyanate-functional monomer, dimer, trimer, or
multimeric adduct thereof, prepolymer, quasi-prepolymer, or
mixtures thereof. Isocyanate-functional compounds may include
monoisocyanates or polyisocyanates that include any isocyanate
functionality of two or more.
[0104] Suitable isocyanate-containing components include
diisocyanates having the generic structure:
O.dbd.C.dbd.N--R--N.dbd.C.dbd.O, where R is preferably a cyclic,
aromatic, or linear or branched hydrocarbon moiety containing from
about 1 to about 20 carbon atoms. The diisocyanate may also contain
one or more cyclic groups or one or more phenyl groups. When
multiple cyclic or aromatic groups are present, linear and/or
branched hydrocarbons containing from about 1 to about 10 carbon
atoms can be present as spacers between the cyclic or aromatic
groups. In some cases, the cyclic or aromatic group(s) may be
substituted at the 2-, 3-, and/or 4-positions, or at the ortho-,
meta-, and/or para-positions, respectively. Substituted groups may
include, but are not limited to, halogens, primary, secondary, or
tertiary hydrocarbon groups, or a mixture thereof. Copolymeric
isocyanates, such as Bayer Desmodur.RTM. HL, which is a copolymer
of TDI and HDI, are preferred.
[0105] Examples of diisocyanates that can be used with the present
invention include, but are not limited to, substituted and isomeric
mixtures including tetramethylene diisocyanate; 2,2'-, 2,4'-, and
4,4'-diphenylmethane diisocyanate; 3,3'-dimethyl-4,4'-biphenylene
diisocyanate; toluene diisocyanate; polymeric MDI;
carbodiimide-modified liquid 4,4'-diphenylmethane diisocyanate;
p-phenylene diisocyanate; m-phenylene diisocyanate; triphenyl
methane-4,4'- and triphenyl methane-4,4'-triisocyanate;
naphthylene-1,5-diisocyanate; 2,4'-, 4,4'-, and 2,2-biphenyl
diisocyanate; polyphenyl polymethylene polyisocyanate; mixtures of
MDI and PMDI; mixtures of PMDI and TDI; ethylene diisocyanate;
propylene-1,2-diisocyanate; tetramethylene-1,2-diisocyanate;
tetramethylene-1,3-diisocyanate; tetramethylene-1,4-diisocyanate;
1,6-hexamethylene-diisocyanate; octamethylene diisocyanate;
decamethylene diisocyanate; 2,2,4-trimethylhexamethylene
diisocyanate; 2,4,4-trimethylhexamethylene diisocyanate;
dodecane-1,12-diisocyanate; cyclobutane-1,3-diisocyanate;
cyclohexane-1,2-diisocyanate; cyclohexane-1,3-diisocyanate;
cyclohexane-1,4-diisocyanate; methyl-cyclohexylene diisocyanate;
2,4-methylcyclohexane diisocyanate; 2,6-methylcyclohexane
diisocyanate; 4,4'-dicyclohexyl diisocyanate; 2,4'-dicyclohexyl
diisocyanate; 4,4' dicyclohexylmethane diisocyanate;
1,3,5-cyclohexane triisocyanate; isocyanatomethylcyclohexane
isocyanate;
1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane;
isocyanatoethylcyclohexane isocyanate;
bis(isocyanatomethyl)-cyclohexane diisocyanate;
4,4'-bis(isocyanatomethyl)dicyclohexane;
2,4'-bis(isocyanatomethyl)dicyclohexane; isophorone diisocyanate;
triisocyanate of HDI; triisocyanate of 2,2,4-trimethyl-1,6-hexane
diisocyanate; 4,4' dicyclohexylmethane diisocyanate;
2,4-hexahydrotoluene diisocyanate; 2,6-hexahydrotoluene
diisocyanate; 1,2-, 1,3-, and 1,4-phenylene diisocyanate; aromatic
aliphatic isocyanate, such as 1,2-, 1,3-, and 1,4-xylene
diisocyanate; m-tetramethylxylene diisocyanate; p-tetramethylxylene
diisocyanate; trimerized isocyanurate of any polyisocyanate, such
as isocyanurate of toluene diisocyanate, trimer of diphenylmethane
diisocyanate, trimer of tetramethylxylene diisocyanate,
isocyanurate of hexamethylene diisocyanate, isocyanurate of
isophorone diisocyanate, and mixtures thereof; dimerized uredione
of any polyisocyanate, such as uretdione of toluene diisocyanate,
uretdione of hexamethylene diisocyanate, and mixtures thereof;
modified polyisocyanate derived from the above isocyanates and
polyisocyanates; and mixtures thereof.
[0106] Saturated diisocyanates, many of which are listed above, are
preferred if a light- and color-stable polyurethane or polyurea
composition is desired. Aromatic aliphatic isocyanates may also be
used to form light-stable materials. Examples of such isocyanates
include 1,2-, 1,3-, and 1,4-xylene diisocyanate;
m-tetramethylxylene diisocyanate; p-tetramethylxylene diisocyanate;
trimerized isocyanurate of any polyisocyanate, such as isocyanurate
of toluene diisocyanate, trimer of diphenylmethane diisocyanate,
trimer of tetramethylxylene diisocyanate, isocyanurate of
hexamethylene diisocyanate, isocyanurate of isophorone
diisocyanate, and mixtures thereof; dimerized uredione of any
polyisocyanate, such as uretdione of toluene diisocyanate,
uretdione of hexamethylene diisocyanate, and mixtures thereof;
modified polyisocyanate derived from the above isocyanates and
polyisocyanates; and mixtures thereof. In addition, the aromatic
aliphatic isocyanates may be mixed with any of the saturated
isocyanates listed above for the purposes of this invention.
[0107] The number of unreacted NCO groups in the polyurea
prepolymer of isocyanate and polyether amine may be varied to
control such factors as the speed of the reaction, the resultant
hardness of the composition, and the like. For instance, the number
of unreacted NCO groups in the polyurea prepolymer of isocyanate
and polyether amine may be less than about 14 percent. In one
embodiment, the polyurea prepolymer has from about 5 percent to
about 11 percent unreacted NCO groups, and even more preferably has
from about 6 to about 9.5 percent unreacted NCO groups. In one
embodiment, the percentage of unreacted NCO groups is about 3
percent to about 9 percent. Alternatively, the percentage of
unreacted NCO groups in the polyurea prepolymer may be about 7.5
percent or less, and more preferably, about 7 percent or less. In
another embodiment, the unreacted NCO content is from about 2.5
percent to about 7.5 percent, and more preferably from about 4
percent to about 6.5 percent.
[0108] When formed, polyurea prepolymers may contain about 10
percent to about 20 percent by weight of the prepolymer of free
isocyanate monomer. Thus, in one embodiment, the polyurea
prepolymer may be stripped of the free isocyanate monomer. For
example, after stripping, the prepolymer may contain about 1
percent or less free isocyanate monomer. In another embodiment, the
prepolymer contains about 0.5 percent by weight or less of free
isocyanate monomer.
[0109] 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.
[0110] The polyurea composition can be formed by crosslinking the
polyurea prepolymer with a single curing agent or a blend of curing
agents. The curing agent of the invention is preferably an
amine-terminated curing agent, more preferably a secondary diamine
curing agent so that the composition contains only urea linkages.
In one embodiment, the amine-terminated curing agent may have a
molecular weight of about 64 or greater. In another embodiment, the
molecular weight of the amine-curing agent is about 2000 or less.
As discussed above, certain amine-terminated curing agents may be
modified with a compatible amine-terminated freezing point
depressing agent or mixture of compatible freezing point depressing
agents.
[0111] Suitable amine-terminated curing agents include, but are not
limited to, ethylene diamine; hexamethylene diamine;
1-methyl-2,6-cyclohexyl diamine;
4,4'-methylenebis-(2,6-diethylaminocyclohexane;
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;
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;
triisopropanolamine; trimethyleneglycol-di-p-aminobenzoate;
polytetramethyleneoxide-di-p-aminobenzoate;
4,4'-methylenebis-(3-chloro-2,6-diethyleneaniline);
4,4'-methylenebis-(2,6-diethylaniline); m-phenylenediamine;
p-phenylenediamine; and mixtures thereof. In one embodiment, the
amine-terminated curing agent is
4,4'-bis-(sec-butylamino)-dicyclohexylmethane. In addition, any of
the polyether amines listed above may be used as curing agents to
react with the polyurea prepolymers. Saturated amine-terminated
curing agents, many of which are listed above, are preferred if a
light- and color-stable polyurethane or polyurea composition is
desired.
[0112] Any method known to one of ordinary skill in the art may be
used to combine the polyisocyanate, polyol, and curing agent of the
present invention. One commonly employed method, known in the art
as a one-shot method, involves concurrent mixing of the
polyisocyanate, polyol, and curing agent. This method results in a
mixture that is inhomogenous (more random) and affords the
manufacturer less control over the molecular structure of the
resultant composition. A preferred method of mixing is known as a
prepolymer method. In this method, the polyisocyanate and the
polyol are mixed separately prior to addition of the curing agent.
This method affords a more homogeneous mixture resulting in a more
consistent polymer composition.
[0113] Due to the very thin nature, it has been found by the
present invention that the use of a castable, reactive material,
which is applied in a fluid form, makes it possible to obtain very
thin outer cover layers on golf balls. Specifically, it has been
found that castable, reactive liquids, which react to form a
urethane elastomer material, provide desirable very thin outer
cover layers.
[0114] The castable, reactive liquid employed to form the urethane
elastomer material can be applied over the core using a variety of
application techniques such as spraying, dipping, spin coating, or
flow coating methods which are well known in the art. An example of
a suitable coating technique is that which is disclosed in U.S.
Pat. No. 5,733,428, the disclosure of which is hereby incorporated
by reference in its entirety by reference thereto.
[0115] The outer cover is preferably formed around the core and
intermediate cover layers by mixing and introducing the material in
the mold halves. It is important that the viscosity be measured
over time, so that the subsequent steps of filling each mold half,
introducing the core into one half and closing the mold can be
properly timed for accomplishing centering of the core cover halves
fusion and achieving overall uniformity. Suitable viscosity range
of the curing urethane mix for introducing cores into the mold
halves is determined to be approximately between about 2,000 cP and
about 30,000 cP, with the preferred range of about 8,000 cP to
about 15,000 cP.
[0116] To start the outer cover formation, mixing of the prepolymer
and curative is accomplished in a motorized mixer including mixing
head by feeding through lines metered amounts of curative and
prepolymer. Top preheated mold halves are filled and placed in
fixture units using pins moving into holes in each mold. After the
reacting materials have resided in top mold halves for about 40 to
about 80 seconds, a core is lowered at a controlled speed into the
gelling reacting mixture. At a later time, a bottom mold half or a
series of bottom mold halves have similar mixture amounts
introduced into the cavity.
[0117] A ball cup holds the ball core through reduced pressure (or
partial vacuum). Upon location of the coated core in the halves of
the mold after gelling for about 40 to about 80 seconds, the vacuum
is released allowing core to be released. The mold halves, with
core and solidified cover half thereon, are removed from the
centering fixture unit, inverted and mated with other mold halves
which, at an appropriate time earlier, have had a selected quantity
of reacting polyurethane prepolymer and curing agent introduced
therein to commence gelling.
[0118] Similarly, U.S. Pat. Nos. 5,006,297 and 5,334,673 both
disclose suitable molding techniques which may be utilized to apply
the castable reactive liquids employed in the present invention.
Further, U.S. Pat. Nos. 6,180,040 and 6,180,722 disclose methods of
preparing dual core golf balls. The disclosures of these patents
are hereby incorporated by reference in their entirety.
[0119] Other methods of molding include reaction injection molding
(RIM) where two liquid components are injected into a mold holding
a pre-positioned core. The liquid components react to form a solid,
thermoset polymeric composition, typically a polyurethane or
polyurea.
[0120] Any of the above layer materials may also comprise additives
known in the art, such as anti-oxidants, dyes, pigments, colorants,
stabilizers, flame retardants, drip retardants, crystallization
nucleators, metal salts, antistatic agents, plasticizers,
lubricants, and combinations comprising two or more of the
foregoing additives. Effective amounts are typically less than 5 wt
%, based on the total weight of the composition, preferably 0.25 wt
% to 2 wt %.
[0121] The compositions may also comprise fillers, including
reinforcing fillers. Exemplary fillers include small particle
minerals (e.g., clay, mica, talc, and the like), glass fibers,
nanoparticles, organoclay, and the like and combinations comprising
one or more of the foregoing fillers. Fillers are typically used in
amounts of 5 wt % to 50 wt %, based on the total weight of the
composition.
[0122] The selection of such filler(s) is dependent upon the type
of golf ball desired (i.e., one-piece, two-piece multi-component,
or wound). Examples of useful fillers include zinc oxide, barium
sulfate, calcium oxide, calcium carbonate and silica, as well as
the other well known corresponding salts and oxides thereof.
Additives, such as nanoparticles, glass spheres, and various
metals, such as titanium and tungsten, can be added to the
polyurethane compositions of the present invention, in amounts as
needed, for their well-known purposes. Additional components which
can be added to the polyurethane composition include UV stabilizers
and other dyes, as well as optical brighteners and fluorescent
pigments and dyes. Such additional ingredients may be added in any
amounts that will achieve their desired purpose.
[0123] The golf balls of the present invention typically have a COR
of greater than about 0.775, preferably greater than about 0.795,
and more preferably greater than about 0.800. The golf balls also
typically have an Atti compression of at least about 40, preferably
from about 50 to 120, and more preferably from about 60 to 110. As
used herein, the term "Atti compression" is defined as the
deflection of an object or material relative to the deflection of a
calibrated spring, as measured with an Atti Compression Gauge, that
is commercially available from Atti Engineering Corp. of Union
City, N.J. Atti compression is typically used to measure the
compression of a golf ball. When the Atti Gauge is used to measure
cores having a diameter of less than 1.680 inches, it should be
understood that a metallic or other suitable shim is used to
normalize the diameter of the measured object to 1.680 inches.
[0124] It should be understood that there is a fundamental
difference between `material hardness` and `hardness` (as measured
directly on a curved surface, such as a golf ball). Material
hardness is defined by the procedure set forth in ASTM-D2240 and
generally involves measuring the hardness of a flat "slab" or
"button" formed of the material of which the hardness is to be
measured. Hardness, when measured directly on a golf ball (or other
spherical surface) is a different measurement and, therefore, many
times produces a different hardness value. This difference results
from a number of factors including, but not limited to, ball
construction (i.e., core type, number of core and/or cover layers,
etc.), ball (or sphere) diameter, and the material composition of
adjacent layers (especially measuring soft, very thin layers over a
layer from a harder material). 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. As used herein, the term "hardness" refers to hardness
measured on the curved surface of the layer being measured (i.e.,
sphere including core+inner cover, sphere including core+inner
cover+intermediate cover, or sphere including core+inner
cover+intermediate cover+outer cover).
[0125] The inner cover layer has a hardness of about 45 to 68 Shore
D, preferably about 50 to 62 Shore D, and more preferably about 52
to 60 Shore D. In preferred embodiments, the inner cover layer
preferably has a hardness of 55 to 60 Shore D, more preferably 56
to 59 Shore D, most preferably 57 to 58 Shore D. Alternatively, the
inner cover layer has a hardness of about 55 to 98 Shore C,
preferably about 66 to 90 Shore C, and more preferably about 74 to
86 Shore C. In preferred embodiments, the inner cover layer
preferably has a hardness of 76 to 85 Shore C, more preferably 78
to 84 Shore C, most preferably 80 to 83 Shore C.
[0126] The intermediate cover layer has a hardness of about 55 to
80 Shore D, preferably about 57 to 75 Shore D, and more preferably
about 61 to 69 Shore D. Alternatively, the intermediate cover layer
has a hardness of about 65 to 100 Shore C, preferably about 72 to
95 Shore C, and more preferably about 74 to 92 Shore C.
[0127] The outer cover layer has a hardness of about 35 to 65 Shore
D, preferably about 40 to 62 Shore D, and more preferably about 52
to 60 Shore D. In preferred embodiments, the outer cover layer
preferably has a hardness of 55 to 60 Shore D, more preferably 56
to 59 Shore D, most preferably 57 to 58 Shore D. Alternatively, the
outer cover layer has a hardness of about 55 to 90 Shore C,
preferably about 62 to 86 Shore C, and more preferably about 68 to
82 Shore C. In preferred embodiments, the outer cover layer
preferably has a hardness of 76 to 85 Shore C, more preferably 78
to 84 Shore C, most preferably 80 to 83 Shore C.
[0128] In a particularly preferred embodiment, a golf ball is
formed from a core, an inner cover layer, an intermediate cover
layer, and an outer cover layer. The core is a single, solid core
having an outer diameter of about 1.52 inches. The inner cover
layer is formed from an ionomer and has a thickness of about 0.035
inches and a hardness of about 58 Shore D. Alternatively, the inner
cover layer has a hardness of about 82 Shore C. The intermediate
layer is formed from a castable, thermosetting polyurethane or
polyurea and has a thickness of about 0.015 inches and a hardness
of about 62 Shore D. Alternatively, the intermediate cover layer
has a hardness of about 90 Shore C. The outer cover layer is formed
from a thermosetting polyurea and has a thickness of about 0.030
inches and a hardness of about 57 Shore D. Alternatively, the outer
cover layer has a hardness of about 80 Shore C.
[0129] The relationship between the inner cover layer, the
intermediate cover layer, and the outer cover layer is also
important to the golf ball of the present invention. The outer
cover layer has a first hardness, the intermediate cover layer has
a second hardness, and the inner cover layer has a third hardness.
The non-ionomeric intermediate layer of the present invention has a
hardness that is greater than the hardness of both the inner cover
layer and the outer cover layer. The second hardness is at least 5
Shore D greater than the first and third hardness values,
preferably at least 10 Shore D greater than the first and third
hardness values, more preferably at least 15 Shore D greater than
the first and third hardness values, and most preferably at least
20 Shore D greater than the first and third hardness values.
[0130] The core of the present invention has an Atti compression of
between about 50 and about 90, more preferably, between about 60
and about 85, and most preferably, between about 70 and about 80.
The outer diameter of the core is about 1.45 inches to 1.58 inches,
more preferably about 1.50 inches to 1.56 inches, most preferably
about 1.51 inches to 1.55 inches.
[0131] The thickness of the inner cover layer is preferably about
0.010 inches to 0.075 inches, more preferably about 0.030 inches to
0.060 inches, most preferably about 0.035 inches to 0.050
inches.
[0132] The thickness of the intermediate cover layer is preferably
about 0.010 inches to 0.075 inches, more preferably about 0.030
inches to 0.060 inches, most preferably about 0.035 inches to 0.050
inches. In one alternative preferred embodiment, the thickness of
the intermediate cover layer is about 0.015 inches to 0.030
inches.
[0133] The thickness of the outer cover layer is preferably about
0.005 inches to 0.045 inches, more preferably about 0.020 inches to
0.040 inches, and most preferably about 0.025 inches to 0.035
inches.
[0134] The flexural modulus of the intermediate layer on the golf
balls, as measured by ASTM method D6272-98, Procedure B, is
typically greater than about 55,000 psi, and is preferably from
about 60,000 psi to 120,000 psi. Preferably, the intermediate layer
compositions of the invention have a higher flexural modulus at a
particular hardness than the inner cover layer ionomeric materials
at the same hardness.
[0135] The golf ball can have an overall diameter of any size.
While the United States Golf Association limits the minimum size of
a golf ball to 1.680 inches, there is no maximum diameter. The golf
ball diameter is preferably about 1.68 inches to 1.74 inches, more
preferably about 1.68 inches to about 1.70 inches, and most
preferably about 1.68 inches.
[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 330 to 392. The dimples may comprise
any width, depth, and edge angle disclosed in the prior art and the
patterns may comprises multitudes of dimples having different
widths, depths and edge angles. Typical dimple coverage is greater
than about 60%, preferably greater than about 65%, and more
preferably greater than about 75%. The parting line configuration
of said pattern may be either a straight line or a staggered wave
parting line (SWPL). Most preferably the dimple number is 330, 332,
or 392 and comprises 5 to 7 dimples sizes and the parting line is a
SWPL.
[0137] 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. 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.
[0138] 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 contain 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.
[0139] While it is apparent that the illustrative embodiments of
the invention disclosed herein fulfill the objective stated above,
it is appreciated that numerous modifications and other embodiments
may be devised by those skilled in the art. Therefore, it will be
understood that the appended claims are intended to cover all such
modifications and embodiments, which would come within the spirit
and scope of the present invention.
* * * * *