U.S. patent application number 15/155227 was filed with the patent office on 2016-09-08 for three-cover-layer golf ball comprising intermediate layer including a plasticized polyester composition.
This patent application is currently assigned to Acushnet Company. The applicant listed for this patent is Acushnet Company. Invention is credited to Mark L. Binette, Robert Blink, David A. Bulpett, Brian Comeau, Michael J. Sullivan.
Application Number | 20160256749 15/155227 |
Document ID | / |
Family ID | 52826642 |
Filed Date | 2016-09-08 |
United States Patent
Application |
20160256749 |
Kind Code |
A1 |
Sullivan; Michael J. ; et
al. |
September 8, 2016 |
Three-Cover-Layer Golf Ball Comprising Intermediate Layer Including
A Plasticized Polyester Composition
Abstract
A golf ball includes a core and a three-layer cover disposed
adjacent the core. The three-layer cover includes an inner cover,
an intermediate cover, and an outer cover. The inner cover includes
a non-ionomeric E/Y copolymer where E is an olefin and Y is a
carboxylic acid. The inner cover has a hardness of about 45 to 68
Shore D. The outer cover includes a castable thermoset polyurethane
and has a hardness of about 40 to 62 Shore D. The intermediate
cover layer, disposed between the inner and outer cover layers, is
formed from a polyester composition including about 40 wt % to
about 99 wt % of a polyester thermoplastic elastomer and about 1 wt
% to about 60 wt % of a plasticizer.
Inventors: |
Sullivan; Michael J.; (Old
Lyme, CT) ; Bulpett; David A.; (Boston, MA) ;
Blink; Robert; (Newport, RI) ; Binette; Mark L.;
(Mattapoisett, MA) ; Comeau; Brian; (Berkley,
MA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Acushnet Company |
Fairhaven |
MA |
US |
|
|
Assignee: |
Acushnet Company
Fairhaven
MA
|
Family ID: |
52826642 |
Appl. No.: |
15/155227 |
Filed: |
May 16, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14584379 |
Dec 29, 2014 |
9339696 |
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15155227 |
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14487225 |
Sep 16, 2014 |
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14584379 |
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|
13723433 |
Dec 21, 2012 |
8834301 |
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14487225 |
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13487480 |
Jun 4, 2012 |
8337333 |
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13723433 |
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12403713 |
Mar 13, 2009 |
8202176 |
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13487480 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C08L 67/025 20130101;
C08K 5/101 20130101; A63B 37/0031 20130101; A63B 37/0039 20130101;
A63B 37/0043 20130101; A63B 37/0033 20130101; A63B 37/0045
20130101; C09D 123/0876 20130101; A63B 37/0024 20130101; A63B
37/0049 20130101; A63B 37/0075 20130101; C08L 23/0876 20130101;
A63B 37/0092 20130101; A63B 37/003 20130101; A63B 37/0076 20130101;
C08K 5/0016 20130101; C08K 5/101 20130101; C08L 67/025 20130101;
C08K 5/0016 20130101; C08L 67/025 20130101; C09D 167/025 20130101;
C08K 5/0016 20130101; C08L 67/025 20130101; C08L 23/0876 20130101;
C08K 5/0016 20130101 |
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 non-ionomeric inner cover layer
comprising an E/Y copolymer where E is an olefin and Y is a
carboxylic acid, the non-ionomeric inner cover being disposed about
the core and having a hardness of about 45 to 68 Shore D; a
castable thermoset polyurethane outer cover layer having a hardness
from about 40 to 62 Shore D; and an intermediate cover layer
disposed between the inner cover layer and outer cover layer, the
intermediate cover layer comprising a polyester composition
comprising about 40 to 99 weight % of a polyester thermoplastic
elastomer and about 10 to 60 weight % of a plasticizer.
2. The golf ball of claim 1, wherein the polyester composition
further comprises an acid copolymer of ethylene and an
.alpha.,.beta.-unsaturated carboxylic acid, optionally including a
softening monomer selected from the group consisting of alkyl
acrylates and methacrylates; and a cation source present in an
amount sufficient to neutralize from about 0 to about 100% of all
acid groups present in the composition.
3. The golf ball of claim 2, wherein the acid groups of the acid
copolymer of ethylene are neutralized by about 80% or greater.
4. The golf ball of claim 1, wherein the plasticizer comprises a
fatty acid ester.
5. The golf ball of claim 4, wherein the fatty acid ester comprises
an alkyl oleate.
6. The golf ball of claim 5, wherein the alkyl oleate comprises
methyl oleate, ethyl oleate, propyl oleate, butyl oleate, or octyl
oleate.
7. The golf ball of claim 1, wherein the intermediate layer
hardness is greater than the inner cover layer hardness.
8. The golf ball of claim 7, wherein the intermediate layer
hardness is greater than the inner cover layer hardness by at least
5 Shore D.
9. The golf ball of claim 1, wherein the intermediate layer
hardness is greater than the outer cover layer hardness.
10. The golf ball of claim 9, wherein the intermediate layer
hardness is greater than the outer cover layer hardness by at least
5 Shore D.
11. The golf ball of claim 1, wherein the core comprises a center
and at least one outer core layer.
12. The golf ball of claim 1, wherein the non-ionomeric inner cover
layer further comprises a polyester/polycarbonate blend, a
polyester resin, an acetal resin, a polyamide resin, a
polyetheramide resin, a polyester resin, a polyester elastomer, a
liquid crystalline polyester, a polyester/polyamide blend, a
poly(arylene ether)/polyester resin, or a polyimide.
13. The golf ball of claim 1, wherein the olefin is ethylene and
the carboxylic acid is acrylic acid, methacrylic acid, crotonic
acid, maleic acid, fumaric acid, itaconic acid, or a combination
thereof.
14. The golf ball of claim 1, wherein the polyester composition has
a Charpy notched impact-resistance of about 15 kJ/m.sup.2 or
greater when measured at 23.degree. C.
15. The golf ball of claim 1, wherein the polyester composition has
a ratio of Charpy notched impact-resistance measured at 23.degree.
C. and measured at -30.degree. C. of at least about 2.0.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of co-pending U.S. patent
Ser. No. 14/584,379, filed Dec. 30, 2014, which is a
continuation-in-part of co-pending U.S. patent application Ser. No.
14/487,225, filed Sep. 16, 2014, which is a continuation-in-part of
U.S. patent application Ser. No. 13/723,433, filed Dec. 21, 2012
and now U.S. Pat. No. 8,834,301, which is a continuation of U.S.
patent application Ser. No. 13/487,480, filed Jun. 4, 2012 and now
U.S. Pat. No. 8,337,333, which is a divisional of co-pending U.S.
patent application Ser. No. 12/403,713, filed Mar. 13, 2009 and now
U.S. Pat. No. 8,202,176, the disclosures of which are incorporated
herein by reference thereto.
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 intermediate cover layer being formed from a
polyester composition.
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 a core, according to
the present invention. In particular, it is desired that this
construction include a thermoplastic non-ionomeric inner cover
layer in conjunction with a stiff, thermoplastic polyurethane or
polyurea intermediate cover layer, and a thermosetting castable
outer cover layer.
SUMMARY OF THE INVENTION
[0007] The present invention is directed to a golf ball having a
core and a cover disposed about the core. The cover includes a
thermoplastic inner cover layer having a hardness between 55 Shore
D and 60 Shore D; an outer cover layer having a hardness between 55
Shore D and 60 Shore D; and a stiff 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 is formed from a non-ionomeric
composition including a non-ionomeric stiffening polymer and at
least one E/Y copolymer or E/X/Y terpolymer, where E is an olefin,
Y is a carboxylic acid, and X is a softening comonomer. The
intermediate cover layer is formed from a stiff thermoplastic
polyurethane or polyurea composition and the cover outer cover
layer is formed from a thermoset 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, preferably by at
least 10 Shore D. The intermediate layer hardness is 60 Shore D or
greater, preferably 65 Shore D or greater, more preferably from 70
Shore D to 90 Shore D.
[0009] The thermoset polyurethane, polyurea, or urethane-urea blend
is preferably a castable thermoset or reaction injection moldable
thermoset. In another embodiment, the outer cover is formed from a
castable thermoset polyurea and the intermediate cover layer is
formed from a stiff thermoplastic polycarbonate-polyurethane. In
one construction, the core is a dual core and includes a center and
at least one outer core layer. Ideally, the core and/or center are
formed from a single homogeneous composition.
[0010] The non-ionomeric inner cover layer may further include a
polyester/polycarbonate blend, a polyester resin, an acetal resin,
a polyamide resin, a polyetheramide resin, a polyester resin, a
polyester elastomer, a liquid crystalline polyester, a
polyester/polyamide blend, a poly(arylene ether)/polyester resin,
or a polyimide. Preferably, the olefin is ethylene; the carboxylic
acid is acrylic acid, methacrylic acid, crotonic acid, maleic acid,
fumaric acid, itaconic acid, or a combination thereof; and the
softening comonomer is vinyl esters of aliphatic carboxylic acids
of 2 to about 10 carbon atoms, alkyl ethers of 1 to about 10 carbon
atoms, alkyl acrylates or alkyl alkylacrylates of 1 to about 10
carbon atoms, or blends thereof.
[0011] The non-ionomeric composition is preferably an E/Y copolymer
comprising an ethylene/acrylic acid copolymer or an
ethylene/methacrylic acid copolymer. In an alternative embodiment,
the non-ionomeric composition is an E/X/Y terpolymer comprising an
ethylene/methyl acrylate/acrylic acid terpolymer, an
ethylene/n-butyl acrylate/methacrylic acid terpolymer, or an
ethylene/isobutyl-acrylate/methacrylic acid terpolymer.
[0012] The stiffening polymer includes polyamides, single-site
catalyzed polymers, metallocene-catalyzed polymers, polyesters,
poly(ethylene terephthalate), poly(butylene terephthalate),
poly(propylene terephthalate), poly(trimethylene terephthalate),
poly(ethylene naphthenate), polystyrene polymers,
poly(styrene-co-maleic anhydride), acrylonitrile-butadiene-styrene,
poly(styrene sulfonate), polyethylene styrene, grafted
polypropylenes, grafted polyethylenes, polyvinyl chlorides, grafted
polyvinyl chlorides; polyvinyl acetates having less than about 9%
of vinyl acetate by weight, polycarbonates, blends of polycarbonate
and acrylonitrile-butadiene-styrene, blends of polycarbonate and
polyurethane, polyvinyl alcohols, polyvinyl alcohol copolymers,
polyethers, polyarylene ethers, polyphenylene oxides; block
copolymers of alkenyl aromatics with vinyl aromatics and polyamic
esters, polyimides, polyetherketones, or polyamideimides.
[0013] A combination of the inner cover, the intermediate cover,
and the outer cover have a total thickness of 0.125 inches or less,
preferably 0.115 inches or less. The outer cover layer hardness is
typically less than the inner cover layer hardness.
[0014] The present invention is also directed to a golf ball
comprising a core and a cover. The cover includes an non-ionomeric
inner cover layer formed from a non-ionomeric composition including
a non-ionomeric stiffening polymer and an E/X/Y terpolymer, where E
is an olefin, Y is a carboxylic acid, and X is a softening
comonomer, the inner cover 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 an intermediate cover layer
formed from a stiff thermoplastic polyurethane or polyurea
composition 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%.
[0015] The present invention is further directed to a golf ball
having a core and a cover. The cover includes a non-ionomeric inner
cover layer formed from an E/Y copolymer where E is an olefin and Y
is a carboxylic acid, the inner cover 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
stiff thermoplastic polyurethane or polyurea intermediate cover
layer disposed between the inner and outer cover layers, the
non-ionomeric intermediate cover layer 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%.
[0016] The present invention is also directed to a golf ball
including a core and a three-layer cover disposed adjacent the
core. The three-layer cover includes an inner cover, an
intermediate cover, and an outer cover. The inner cover includes a
non-ionomeric E/Y copolymer where E is an olefin and Y is a
carboxylic acid. The inner cover has a hardness of about 45 to 68
Shore D. The outer cover includes a castable thermoset polyurethane
and has a hardness of about 40 to 62 Shore D. The intermediate
cover layer, disposed between the inner and outer cover layers, is
formed from a polyamide composition, where the polyamide
composition includes a transparent polyamide having a light
transmission of about 50% or greater.
[0017] The transparent polyamide may be a transparent
polyether-amide block copolymer. Alternatively, the transparent
polyamide has an amorphous, quasi-amorphous, semicrystalline, or
microcrystalline structure. Preferably, the transparent polyamide
has a glass transition temperature in the range of about 75.degree.
C. to about 160.degree. C., more preferably about 80.degree. C. to
about 95.degree. C. The transparent polyamide may also have a
Charpy notched impact-resistance of about 15 kJ/m.sup.2 or greater
when measured at 23.degree. C., more preferably about 50 kJ/m.sup.2
or greater when measured at 23.degree. C. The transparent polyamide
preferably has a ratio of Charpy notched impact-resistance measured
at 23.degree. C. and measured at -30.degree. C. of at least about
2.0.
[0018] In a preferred embodiment, the transparent polyamide has a
light transmission of about 80% or greater as measured by ISO 13468
using a 2-mm thick sample at a wavelength of 560 nm. More
preferably the light transmission is about 90% or greater. In one
embodiment, the transparent polyamide further comprises about 1% by
weight to about 60% by weight of an acid anhydride-modified
polyolefin.
[0019] The intermediate layer hardness is preferably greater than
the inner cover layer hardness. In a preferred embodiment, the
intermediate layer hardness is greater than the inner cover layer
hardness by at least 5 Shore D. Alternatively, the intermediate
layer hardness is greater than the outer cover layer hardness and,
optionally, the intermediate layer hardness is greater than the
outer cover layer hardness by at least 5 Shore D. In one
embodiment, the core includes a center and at least one outer core
layer.
[0020] The non-ionomeric inner cover layer may further include a
polyester/polycarbonate blend, a polyester resin, an acetal resin,
a polyamide resin, a polyetheramide resin, a polyester resin, a
polyester elastomer, a liquid crystalline polyester, a
polyester/polyamide blend, a poly(arylene ether)/polyester resin,
or a polyimide. The olefin is preferably ethylene and the
carboxylic acid is acrylic acid, methacrylic acid, crotonic acid,
maleic acid, fumaric acid, itaconic acid, or a combination
thereof.
[0021] The present invention is additionally directed to a golf
ball including a core and a three-layer cover disposed adjacent the
core. The three-layer cover includes a non-ionomeric inner cover
layer including an E/Y copolymer where E is an olefin and Y is a
carboxylic acid, the inner cover being disposed about the core and
having a hardness of 45 Shore D to 68 Shore D; a castable thermoset
polyurethane outer cover layer having a hardness from about 40
Shore D to 62 Shore D; and an intermediate cover layer disposed
between the inner and outer cover layers, the intermediate layer
including a polyamide composition and having a hardness greater
than a hardness of the inner cover layer. The polyamide composition
includes a transparent polyamide having a light transmission of
about 80% or greater and a glass transition temperature in the
range of about 75.degree. C. to about 160.degree. C.
[0022] The present invention is further directed to a golf ball
including a core and a two-layer cover disposed adjacent the core.
The two-layer cover includes an inner cover layer disposed about
the core, the intermediate layer including a polyamide composition;
and a castable thermoset polyurethane outer cover layer having a
hardness from about 40 to 62 Shore D. The polyamide composition
includes a transparent polyamide having a light transmission of
about 50% or greater and a glass transition temperature in the
range of about 75.degree. C. to about 160.degree. C.
[0023] The present invention is directed to a golf ball that
includes a core and a three-layer cover disposed adjacent the core.
The three-layer cover includes an inner cover, an intermediate
cover, and an outer cover. The inner cover includes a non-ionomeric
E/Y copolymer where E is an olefin and Y is a carboxylic acid. The
inner cover has a hardness of about 45 to 68 Shore D. The outer
cover includes a castable thermoset polyurethane and has a hardness
of about 40 to 62 Shore D. The intermediate cover layer, disposed
between the inner and outer cover layers, is formed from a
polyester composition including about 40 wt % to about 99 wt % of a
polyester thermoplastic elastomer and about 1 wt % to about 60 wt %
of a plasticizer.
[0024] Preferably, the polyester thermoplastic elastomer is a
polyester-polyether block copolymer. In one embodiment, the
polyester-polyether block copolymer has a flex modulus of about
50,000 psi or less. The polyester composition may further include
an acid copolymer of ethylene and an .alpha.,.beta.-unsaturated
carboxylic acid, and a cation source present in an amount
sufficient to neutralize from about 0 to about 100% of all acid
groups present in the composition. Optionally, the composition
includes a softening monomer, such as alkyl acrylate and alkyl
methacrylate.
[0025] Preferably, the acid groups of the acid copolymer of
ethylene are neutralized by about 80% or greater, more preferably
about 90% or greater, and most preferably about 100%. The
plasticizer is preferably present in an amount of about 10 wt % to
about 30 wt %. In one embodiment, the plasticizer is a fatty acid
ester. Alternatively, the plasticizer includes an alkyl oleate.
Preferably, the alkyl oleate is methyl oleate, ethyl oleate, propyl
oleate, butyl oleate, or octyl oleate.
[0026] In one preferred embodiment, the intermediate layer hardness
is greater than the inner cover layer hardness, more preferably the
intermediate layer hardness is greater than the inner cover layer
hardness by at least 5 Shore D. The intermediate layer hardness may
also be greater than the outer cover layer hardness, preferably the
intermediate layer hardness is greater than the outer cover layer
hardness by at least 5 Shore D. The core may be a multi-layer core
and include a center and at least one outer core layer.
[0027] The non-ionomeric inner cover layer may further include a
polyester/polycarbonate blend, a polyester resin, an acetal resin,
a polyamide resin, a polyetheramide resin, a polyester resin, a
polyester elastomer, a liquid crystalline polyester, a
polyester/polyamide blend, a poly(arylene ether)/polyester resin,
or a polyimide. In one embodiment, the olefin is ethylene and the
carboxylic acid is acrylic acid, methacrylic acid, crotonic acid,
maleic acid, fumaric acid, itaconic acid, or a combination
thereof.
[0028] Preferably, the polyester composition has a Charpy notched
impact-resistance of about 15 kJ/m.sup.2 or greater when measured
at 23.degree. C. or, alternatively, a ratio of Charpy notched
impact-resistance measured at 23.degree. C. and measured at
-30.degree. C. of at least about 2.0.
BRIEF DESCRIPTION OF THE DRAWINGS
[0029] These and other aspects of the present invention may be more
fully understood with reference to, but not limited by, the
following drawings.
[0030] FIG. 1 is a representative cross section of a golf ball of
the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0031] 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.
[0032] 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 cover layer 16, and an outer cover layer 18.
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.
[0033] 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, which are incorporated herein, in their entirety, by
reference.
[0034] 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, ans most preferably,
less than about 2 percent.
[0035] 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.
[0036] 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.
[0037] 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.
[0038] 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.
[0039] 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.
[0040] 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.
[0041] 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.
[0042] 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.
[0043] 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.
[0044] 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.
[0045] The inner cover layer of the present invention is preferably
formed from a non-ionomeric composition comprising a non-ionomeric
stiffening polymer and at least one E/Y copolymer or E/X/Y
terpolymer, where E is an olefin, Y is a carboxylic acid, and X is
a softening comonomer. The stiffening polymer provides the
non-ionomenic composition with a flexural modulus and material
hardness substantially greater than the copolymer or
terpolymer.
[0046] Preferably, the olefin is ethylene; the carboxylic acid is
acrylic acid, methacrylic acid, crotonic acid, maleic acid, fumaric
acid, itaconic acid, or a combination thereof; and the softening
comonomer is vinyl esters of aliphatic carboxylic acids of 2 to
about 10 carbon atoms, alkyl ethers of 1 to about 10 carbon atoms,
alkyl acrylates or alkyl alkylacrylates of 1 to about 10 carbon
atoms, or blends thereof. Preferred E/Y copolymers are
ethylene/acrylic acid copolymers or ethylene/methacrylic acid
copolymers, and preferred E/X/Y terpolymers are ethylene/methyl
acrylate/acrylic acid terpolymers, ethylene/n-butyl
acrylate/methacrylic acid terpolymers, or
ethylene/isobutyl-acrylate/methacrylic acid terpolymers.
[0047] The copolymer or terpolymer preferably has an acid content
of from about 1% to about 30% by weight, a melt flow rate of from
about 1 g/10-min to about 500 g/10-min, a water vapor transmission
rate ("WVTR") of from about 0.01 to about 0.9 g-mm/m.sup.2/day at
38.degree. C. and 90% relative humidity, a flexural modulus of from
about 5,000 psi to about 55,000 psi, and a material hardness of
from about 20 Shore D to about 65 Shore D. The non-ionomeric
composition preferably has a flexural modulus of at least about
30,000 psi, and a material hardness of at least about 55 Shore D.
The copolymer or terpolymer may be present in an amount of from
about 5% to about 95% by weight of the non-ionomeric
composition.
[0048] The stiffening polymer may be homopolymeric or copolymeric,
and comprises polyamides, single-site catalyzed polymers,
metallocene-catalyzed polymers, polyesters, poly(ethylene
terephthalate), poly(butylene terephthalate), poly(propylene
terephthalate), poly(trimethylene terephthalate), poly(ethylene
naphthenate), polystyrene polymers, poly(styrene-co-maleic
anhydride), acrylonitrile-butadiene-styrene, poly(styrene
sulfonate), polyethylene styrene, grafted polypropylenes, grafted
polyethylenes, polyvinyl chlorides; grafted polyvinyl chlorides;
polyvinyl acetates having less than about 9% of vinyl acetate by
weight, polycarbonates, blends of polycarbonate and
acrylonitrile-butadiene-styrene, blends of polycarbonate and
polyurethane, polyvinyl alcohols, polyvinyl alcohol copolymers,
polyethers, polyarylene ethers, polyphenylene oxides; block
copolymers of alkenyl aromatics with vinyl aromatics and polyamic
esters, polyimides, polyetherketones, polyamideimides, or blends
thereof. Preferably, the stiffening polymer is compatibilized with
at least one grafted or copolymerized functional group such as
maleic anhydride, amine, epoxy, isocyanate, hydroxyl, carbonate,
sulfonate, phosphonate, or a combination thereof. The stiffening
polymer may be present in an amount of from about 95% to about 5%
by weight of the non-ionomeric composition.
[0049] The non-ionomeric acid polymer can be an E/Y copolymer or an
E/X/Y terpolymer. E is an olefin such as ethylene. Y is a
carboxylic acid such as acrylic, methacrylic, crotonic, maleic,
fumaric, itaconic acid, or combinations thereof. X is a softening
comonomer, such as vinyl esters of aliphatic carboxylic acids
wherein the acid has 2 to about 10 carbon atoms, alkyl ethers
wherein the alkyl group has 1 to about 10 carbon atoms, alkyl
acrylates wherein the alkyl group has 1 to about 10 carbon atoms,
or alkyl alkylacrylates such as alkyl methacrylates wherein the
alkyl group has 1 to about 10 carbon atoms. Suitable softening
comonomers X include vinyl acetate, methyl acrylate, methyl
methacrylate, ethyl acrylate, ethyl methacrylate, iso-butyl
acrylate, n-butyl acrylate, butyl methacrylate, or the like.
Specific examples of the non-ionomeric acid copolymer include
ethylene/acrylic acid copolymers ("EAA") and ethylene/methacrylic
acid copolymers ("EMAA"). Examples of the non-ionomeric acid
terpolymer are ethylene/methyl acrylate/acrylic acid terpolymers
("EMAAA"), ethylene/n-butyl acrylate/methacrylic acid terpolymers,
and ethylene/isobutyl acrylate/methacrylic acid terpolymers.
Commercially, EAA resins are available from Dow Chemical under the
tradename of Primacor.RTM. and from ExxonMobil Chemical under the
trade name of Escor.RTM., EMAA resins are available from E.I. du
Pont de Nemours and Company under the tradename of Nucrel.RTM., and
EMAAA resins are available from ExxonMobil Chemical under the trade
name of Escor.RTM. AT.
[0050] Preferably, the acid content within the non-ionomeric acid
copolymers or terpolymers ranges from about 1% to about 30% by
weight, more preferably from about 3% to about 25%, and most
preferably from about 5% to about 20%. Such non-ionomeric acid
copolymers and terpolymers typically have high MFR, preferably
ranging from about 1 g/10-min to about 500 g/10-min, more
preferably from about 3 g/10-min to about 75 g/10-min, and most
preferably from about 3 g/10 min to about 50 g/10 min. For example,
EMAA resins such as Nucrel.RTM. 599 and 2940, both available from
DuPont, have a respective acid content of 10% and 19% by weight,
and a respective MFR of 500 g/10-min and 395 g/10-min. In
comparison to Surlyn.RTM. D ionomers (MFR about 1-14 g/10-min),
EMAA resins clearly have superior flow characteristic under
heat.
[0051] In particular, the suitable non-ionomeric acid copolymers
and terpolymers have a flexural modulus of preferably from about
5,000 psi to about 55,000 psi, more preferably from about 10,000
psi to about 30,000 psi. The non-ionomeric acid copolymers and
terpolymers also has a material hardness of preferably from about
20 Shore D to about 65 Shore D, more preferably from about 40 Shore
D to about 65 Shore D. The non-ionomeric acid copolymers and
terpolymers further have a WVTR of from about 0.01 to about 0.9
g-mm/m.sup.2/day at 38.degree. C. and 90% relative humidity. Other
choices for the non-ionomenrc acid copolymers and terpolymers are
known to one of ordinary skill in the art, and include those
disclosed in U.S. Pat. Nos. 6,124,389; 5,981,654; 5,516,847; and
5,397,840, all of which are incorporated by reference in their
entirety.
[0052] The intermediate cover may also be formed from or include
impact modified, non-ionomeric thermoplastic
polycarbonate/polyester copolymers or blends thereof. These
copolymers or blends thereof have increased durability, improved
impact resistance, and relatively lower flexural modulus. In one
embodiment, the impact modified thermoplastic
polycarbonate/polyester copolymer or blend for use in the
intermediate cover layers has a flexural modulus of less than about
100,000 psi, preferably less than about 80,000 psi. More
preferably, the impact modified thermoplastic
polycarbonate/polyester copolymer or blend thereof has a flexural
modulus between about 50,000 and about 70,000 psi. Flexural modulus
as used herein is measured in accordance with ASTM method
D-6272-02, Procedure B, a Test speed 0.5 in/min.
[0053] Preferred thermoplastic polycarbonate/polyester copolymers
or blends thereof include, but are not limited to,
polycarbonate/poly(butylene terephthalate) (PC/PBT). Suitable
PC/PBT are commercially-available under the tradenames Xylex.RTM.
and Xenoy.RTM. from General Electric Corporation of Pittsfield,
Mass., or Ultradur.RTM. from BASF or Makroblend.RTM. from Bayer.
Xylex.RTM.-type chemistries, such as those disclosed in U.S. Pat.
No. 7,358,305, the disclosure of which is incorporated herein in
its entirety by reference thereto, are the most preferred
intermediate cover layer materials.
[0054] The PC/PBT blend may also be modified by blending with, for
example, acrylonitrile butadiene styrene (ABS) plastics. Other
suitable polymers that can be used as stand alone or along with the
polycarbonate/polyester copolymers and blends in accordance with
this invention include, but are not limited to:
[0055] 1) Polyesters, such as polybutylene terephthalate (PBT)
commercially available as Crastin.RTM. from DuPont; polyethylene
terephthalate, such as DuPont Rynite.RTM.; and rigid Hytrel.RTM.
grades from DuPont, such as Hytrel.RTM. 3078, 4068, 5556, 6356,
7246, and 8238. Hytrel.RTM. is a block copolymer of a crystalline
hard segment (i.e., PBT) and an amorphous soft segment (i.e., a
polyether, such as THF). DuPont Thermx.RTM. PCT polyester is also a
suitable material and is based on poly(cyclohexene-dimethylene
terephthalate) chemistry.
[0056] Other suitable polyester resins include crystalline
polyester resins such as polyester resins derived from an aliphatic
or cycloaliphatic diol, or mixtures thereof, containing from about
2 to 10 carbon atoms and at least one aromatic dicarboxylic acid.
Preferred polyesters are derived from an aliphatic diol and an
aromatic dicarboxylic acid. The polyester resin may comprise one or
more resins selected from linear polyester resins, branched
polyester resins and copolymeric polyester resins. Suitable linear
polyester resins include polyalkylene phthalates, such as
polyethylene terephthalate, polybutylene terephthalate, and
polypropylene terephthalate; polycycloalkylene phthalates, such as
polycyclohexanedimethanol terephthalate; polyalkylene naphthalates,
such as polybutylene-2,6-naphthalate and
polyethylene-2,6-naphthalate; and polyalkylene dicarboxylates, such
as polybutylene dicarboxylate.
[0057] Preferably, copolymeric polyester resins include
polyesteramide copolymers, cyclohexanedimethanol-terephthalic
acid-isophthalic acid copolymers and
cyclohexanedimethanol-terephthalic acid-ethylene glycol copolymers.
The polyester component can, without limitation, comprise the
reaction product of a glycol portion comprising
1,4-cyclohexanedimethanol and ethylene glycol, wherein the ethylene
glycol is greater than 60 mole percent based on the total moles of
1,4-cyclohexanedimethanol and ethylene glycol with an acid portion
comprising terephthalic acid, or isophthalic acid or mixtures of
both acids.
[0058] The copolyester may also be a copolyester where the glycol
portion has a predominance of ethylene glycol over
1,4-cyclohexanedimethanol, preferably is about greater than 60
molar percent of ethylene glycol based on the total mole percent of
ethylene glycol and 1,4-cyclohexanedimethanol, and the acid portion
is terephthalic acid. In another embodiment of the present
invention the polyester comprises structural units derived from
terephthalic acid and a mixture of 1,4-cyclohexane dimethanol and
ethylene glycol, wherein said ethylene glycol is greater than about
75 mole percent based on total moles of 1,4-cyclohexane dimethanol
and ethylene glycol. In another embodiment, the polyester resin has
an intrinsic viscosity of from about 0.4 to about 2.0 dL/g as
measured in a 60:40 phenol/tetrachloroethane mixture at
23-30.degree. C.
[0059] The polyesters may also be derived from structural units
comprising xylene glycol or, alternatively, from structural units
comprising at least one of o-xylene glycol, m-xylene glycol, and
p-xylene glycol. Preferably, the polyester is derived from
structural units comprising p-xylene glycol. The xylene glycol
should be present in an amount at least greater than about 40 mole
percent, more preferably from about 50 to 100 mole percent, most
preferably about 100 mole percent.
[0060] The polyester may optionally comprise straight chain,
branched, or cycloaliphatic diols containing from 2 to 12 carbon
atoms. Examples of such diols include but are not limited to
ethylene glycol; propylene glycol, such as 1,2- and 1,3-propylene
glycol; 2,2-dimethyl-1,3-propane diol; 2-ethyl, 2-methyl,
1,3-propane diol; 1,3- and 1,5-pentane diol; dipropylene glycol;
2-methyl-1,5-pentane diol; 1,6-hexane diol; dimethanol decalin,
dimethanol bicyclo octane; 1,4-cyclohexane dimethanol and
particularly its cis- and trans-isomers; triethylene glycol;
1,10-decane diol; and mixtures thereof. The diol may also include
glycols, such as ethylene glycol, propylene glycol, butanediol,
hydroquinone, resorcinol, trimethylene glycol, 2-methyl-1,3-propane
glycol, 1,4-butanediol, hexamethylene glycol, decamethylene glycol,
1,4-cyclohexane dimethanol, or neopentylene glycol. Chemical
equivalents to the diols include esters, such as dialkylesters,
diaryl esters, and the like.
[0061] The polyester may optionally comprise polyvalent alcohols
which include, but are not limited to, an aliphatic polyvalent
alcohol, an alicyclic polyvalent alcohol, and an aromatic
polyvalent alcohol, including ethylene glycol, propylene glycol,
1,3-propanediol, 2,3-butanediol, 1,4-butanediol, 1,5-pentanediol,
1,6-hexanediol, neopentyl glycol, diethylene glycol, dipropylene
glycol, 2,2,4-trimethyl-1,3-pentanediol, polyethylene glycol,
polypropylene glycol, polytetramethylene glycol, trimethylolethane,
trimethylolpropane, glycerin, pentaerythritol, 1,4-cyclohexanediol,
1,4-cyclohexanedimethanol, spiroglycol, tricyclodecanediol,
tricyclodecanedimethanol, m-xylene glycol, o-xylene glycol,
1,4-phenylene glycol, bisphenol A, lactone polyester and polyols. A
resin obtained by capping the polar group in the end of the polymer
chain using an ordinary compound capable of capping an end may also
be used.
[0062] Block copolyester resin components are also useful, and can
be prepared by the transesterification of (a) straight or branched
chain poly(alkylene terephthalate) and (b) a copolyester of a
linear aliphatic dicarboxylic acid and, optionally, an aromatic
dibasic acid such as terephthalic or isophthalic acid with one or
more straight or branched chain dihydric aliphatic glycols. The
polyesters are preferably a polyether ester block copolymer
consisting of a thermoplastic polyester as the hard segment and a
polyalkylene glycol as the soft segment.
[0063] The polyester can be present in the composition at about 1
to about 99 wt %, based on the total weight of the composition.
Within this range, it is preferred to use at least about 25 wt %,
more preferably at least about 30 wt % of the polyester. Preferred
polyesters have an intrinsic viscosity (as measured in 60:40
solvent mixture of phenol/tetrachloroethane at 25.degree. C.)
ranging from about 0.1 to about 1.5 dL/g. Polyesters branched or
unbranched and generally will have a weight average molecular
weight of from about 5,000 to about 150,000, preferably from about
8,000 to about 95,000 as measured by gel permeation chromatography
using 95:5 weight percent of chloroform:hexafluroisopropanol
mixture. Other suitable materials include thermoplastic aliphatic
and aromatic polycarbonates and copolymers thereof.
[0064] 2) Polyester blends comprising polyamides having at least
one terminal acid group, such as those comprising (A) about 99.98
to about 95 wt % of a polyester which comprises (1) a dicarboxylic
acid component comprising repeat units from at least 85 mole
percent terephthalic acid; and (2) a diol component repeat unit
from at least 85 mole percent ethylene glycol, based on 100 mole
percent dicarboxlic acid and 100 mole percent diol; and (B) a
polyamide wherein at least 50% of the polyamide end groups are acid
groups. The polyester (A), is typically selected from polyethylene
terephthalate, polyethylene naphthalenedicarboxylate or
copolyesters thereof. The acid component of polyester (A) contains
repeat units from at least about 80 mole percent terephthalic acid,
naphthlenedicarboxylic acid or mixtures thereof and at least about
85 mole percent ethylene glycol, based on 100 mole percent
dicarboxylic acid and 100 mole percent diol.
[0065] 3) Polyamides are another preferred intermediate cover layer
material. Nylon 11, 12 and copolymers and toughened versions are
also preferred, such as those disclosed in U.S. Pat. No. 6,800,690,
the disclosure of which is incorporated herein in its entirety by
reference thereto. Rigid grades of Pebax.RTM. poly(amide-ester or
amide-ether) are also suitable materials. Other polymers include
polyimides, polyether-ether ketones, and liquid crystalline
polymers. Filled or reinforced versions of any of these materials
are also suitable. Sorona.RTM., commercially-available from DuPont,
is another preferred intermediate cover layer material. DuPont
Sorona.RTM. EP thermoplastic polymers contain between 20% and 37%
renewably sourced material (by weight) derived from corn. The new
material exhibits performance and molding characteristics similar
to high-performance PBT (polybutylene terephthalate).
[0066] 4) Compatibilized poly(arylene ether)/polyester compositions
having stable phase morphology. The composition exhibits a unique
combination of good heat resistance, dimensional stability, nominal
strain at break and impact properties. Surprisingly it has been
discovered that the amount of the disperse phase comprising
poly(arylene ether) in relation to the amount of the total
composition is critical to the formation of a stable morphology.
The disperse phase comprising poly(arylene ether) is present in an
amount that is less than or equal to 35 wt % based on the total
weight of the composition. The impact modifier may reside in the
disperse phase but may also be present at the interface between the
phases. When the impact modifier resides in the disperse phase, the
combined amount of impact modifier and poly(arylene ether) is less
than 35 weight percent (wt %), based on the total weight of the
composition. The exact amount and types or combinations of
poly(arylene ether), impact modifier and polyester will depend, in
part, on the requirements needed in the final blend composition.
Most often, the poly(arylene ether) and impact modifier are present
in an amount of 5 to 35 wt %, or, more specifically, 10 to 25 wt %,
based on the total weight of the composition.
[0067] The poly(arylene ether) can comprise molecules having
aminoalkyl-containing end group(s), typically located in an ortho
position to the hydroxy group. Also frequently present are
tetramethyl diphenylquinone end groups, typically obtained from
reaction mixtures in which tetramethyl diphenylquinone by-product
is present.
[0068] The poly(arylene ether) can be in the form of a homopolymer;
a copolymer; a graft copolymer; an ionomer; or a block copolymer;
as well as combinations comprising two or more of the foregoing
polymers. Poly(arylene ether) includes polyphenylene ether
comprising 2,6-dimethyl-1,4-phenylene ether units optionally in
combination with 2,3,6-trimethyl-1,4-phenylene ether units.
[0069] At least a portion of the poly(arylene ether) is
functionalized with a polyfunctional compound (functionalizing
agent) such as a polycarboxylic acid or those compounds having in
the molecule both (a) a carbon-carbon double bond or a
carbon-carbon triple bond and b) at least one carboxylic acid,
anhydride, amino, imide, hydroxy group or salts thereof. Examples
of such polyfunctional compounds include maleic acid, maleic
anhydride, fumaric acid, and citric acid. The poly(arylene ether)
can be functionalized prior to making the composition or can be
functionalized as part of making the composition. Furthermore,
prior to functionalization the poly(arylene ether) can be extruded,
for example to be formed into pellets. It is also possible for the
poly(arylene ether) to be melt mixed with other additives that do
not interfere with functionalization. Exemplary additives of this
type include flame retardants, flow promoters, and the like.
[0070] In some embodiments the poly(arylene ether) can comprise 0.1
wt % to 90 wt % of structural units derived from a functionalizing
agent. Within this range, the poly(arylene ether) can comprise less
than or equal to 80 wt %, or, more specifically, less than or equal
to 70 wt % of structural units derived from functionalizing agent,
based on the total weight of the poly(arylene ether).
[0071] Examples of suitable polyesters are poly(allylene
dicarboxylate)s, liquid crystalline polyesters, polyarylates, and
polyester copolymers such as copolyestercarbonates and
polyesteramides. Also included are polyesters that have been
treated with relatively low levels of diepoxy or multi-epoxy
compounds. It is also possible to use branched polyesters in which
a branching agent, for example, a glycol having three or more
hydroxyl groups or a trifunctional or multifunctional carboxylic
acid has been incorporated. Treatment of the polyester with a
trifunctional or multifunctional epoxy compound, for example,
triglycidyl isocyanurate can also be used to make branched
polyester. Furthermore, it is sometimes desirable to have various
concentrations of acid and hydroxyl end groups on the polyester,
depending on the ultimate end-use of the composition.
[0072] Liquid crystalline polyesters having melting points less
that 380.degree. C. and comprising recurring units derived from
aromatic diols, aliphatic or aromatic dicarboxylic acids, and
aromatic hydroxy carboxylic acids are also useful. Mixtures of
polyesters are also sometimes suitable.
[0073] The composition can comprise 40 to 90 wt % of the polyester,
based on the total weight of the composition. Within this range the
composition can comprise less than or equal to 80 wt %, or, more
specifically, less than or equal to 75 wt %, or, even more
specifically, less than or equal to 65 wt % polyester. Also within
this range, the composition can comprise greater than or equal to
45 wt %, or, more specifically, greater than or equal to 50 wt %
polyester.
[0074] The composition also comprises an impact modifier. In many
embodiments the impact modifier resides primarily in the
poly(arylene ether) phase. Examples of suitable impact modifiers
include block copolymers; elastomers such as polybutadiene; random
copolymers such as ethylene vinyl acetate; and combinations
comprising two or more of the foregoing impact modifiers.
[0075] Exemplary block copolymers include A-B diblock copolymers
and A-B-A triblock copolymers having one or two blocks A, which
comprise structural units derived from an alkenyl aromatic monomer,
for example styrene; and a rubber block, B, which generally
comprises structural units derived from a diene such as isoprene or
butadiene. The diene block may be partially hydrogenated. Mixtures
of these diblock and triblock copolymers are especially useful.
[0076] Suitable A-B and A-B-A copolymers include, but are not
limited to, polystyrene-polybutadiene;
polystyrene-poly(ethylene-butylene); polystyrene-polyisoprene;
polystyrene-poly(ethylene-propylene);
poly(alpha-methylstyrene)-polybutadiene;
poly(alpha-methylstyrene)-poly(ethylene-butylene);
polystyrene-polybutadiene-polystyrene;
polystyrene-poly(ethylene-butylene)-polystyrene;
polystyrene-polyisoprene-polystyrene;
polystyrene-poly(ethylene-propylene)-polystyrene;
poly(alpha-methylstyrene)-polybutadiene-poly(alpha-methylstyrene);
as well as selectively hydrogenated versions thereof, and the like,
as well as combinations comprising two or more of the foregoing
impact modifiers. Such A-B and A-B-A block copolymers are available
commercially from a number of sources, including Phillips Petroleum
under the trademark SOLPRENE, Kraton Polymers, under the trademark
KRATON, Dexco under the trademark VECTOR, and Kuraray under the
trademark SEPTON.
[0077] In addition to the poly(arylene ether), polyester, and
impact modifier, the composition is made using a polymeric
compatibilizer having an average of greater than or equal to 3
pendant epoxy groups per molecule. In some embodiments the
polymeric compatibilizer has an average of at least 8 pendant epoxy
groups per molecule.
[0078] Illustrative examples of suitable compatibilizers include,
but are not limited to, copolymers of glycidyl methacrylate (GMA)
with alkenes, copolymers of GMA with alkenes and acrylic esters,
copolymers of GMA with alkenes and vinyl acetate, copolymers of GMA
and styrene. Suitable alkenes comprise ethylene, propylene, and
mixtures of two or more of the foregoing. Suitable acrylic esters
comprise alkyl acrylate monomers, including, but not limited to,
methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate,
and combinations of the foregoing alkyl acrylate monomers. When
present, the acrylic ester may be used in an amount of 15 wt % to
35 wt % based on the total amount of monomer used in the copolymer.
When present, vinyl acetate may be used in an amount of 4 wt % to
10 wt % based on the total amount of monomer used in the copolymer.
Illustrative examples of suitable compatibilizers comprise
ethylene-glycidyl acrylate copolymers, ethylene-glycidyl
methacrylate copolymers, ethylene-glycidyl methacrylate-vinyl
acetate copolymers, ethylene-glycidyl methacrylate-alkyl acrylate
copolymers, ethylene-glycidyl methacrylate-methyl acrylate
copolymers, ethylene-glycidyl methacrylate-ethyl acrylate
copolymers, and ethylene-glycidyl methacrylate-butyl acrylate
copolymers;
[0079] 5) Polycarbonate resins derived from bisphenol A and
phosgene or a blend of two or more polycarbonate resins. The
preferred polycarbonates are high molecular weight aromatic
carbonate polymers have an intrinsic viscosity (as measured in
methylene chloride at 25.degree. C.) ranging from about 0.30 to
about 1.00 dL/g. Polycarbonates may be branched or unbranched and
generally will have a weight average molecular weight of from about
10,000 to about 200,000, preferably from about 20,000 to about
100,000 as measured by gel permeation chromatography. It is
contemplated that the polycarbonate may have various known end
groups. Other polycarbonates useful in the invention are disclosed
in U.S. Pat. No. 7,345,116, which is incorporated herein, in its
entirety, by reference thereto.
[0080] The preferred polycarbonates are preferably high molecular
weight aromatic carbonate polymers have an intrinsic viscosity (as
measured in methylene chloride at 25.degree. C.) ranging from about
0.30 to about 1.00 dL/g. Polycarbonates may be branched or
unbranched and generally will have a weight average molecular
weight of from about 10,000 to about 200,000, preferably from about
20,000 to about 100,000 as measured by gel permeation
chromatography. It is contemplated that the polycarbonate may have
various known end groups. Typically such polyester resins include
crystalline polyester resins such as polyester resins derived from
an aliphatic or cycloaliphatic diol, or mixtures thereof,
containing from about 2 to 20 carbon atoms and at least one
aromatic dicarboxylic acid. Preferred polyesters are derived from
an aliphatic diol and an aromatic dicarboxylic acid. The polyester
resins are typically obtained through the condensation or ester
interchange polymerization of the diol or diol equivalent component
with the diacid or diacid chemical equivalent component.
[0081] Other preferred polycarbonates are disclosed in U.S. Patent
Application Serial No. 2007/0173618, the disclosure of which is
incorporated herein in its entirety by reference thereto.
[0082] 6) Polycarbonate/polyester blends, such as polymers
including (A) about 1 to 99 wt % of at least one polycarbonate (A)
comprising: (1) a diol component comprising about 90 to 100 mole
percent 4,4'-isopropylidenediphenol residues, and (2) 0 to about 10
mole percent modifying diol residues, where the total mole percent
of diol residues is equal to 100 mole percent; and (B) about 99 to
1 wt % of at least one polyester (B) comprising (1) diacid residues
comprising about 70 to 100 mole percent dicarboxylic acid units,
such as terephthalic acid residues, isophthalic acid residues, or
mixtures thereof; and 0 to about 30 mole percent of modifying
dicarboxylic acid residues, wherein the total mole percent of
diacid residues is equal to 100 mole percent; and (2) diol residues
comprising about 40 to 99.9 mole percent 1,4-cyclohexanedimethanol
residues, 0.1 to about 60 mole percent neopentyl glycol residues,
and 0 to about 10 mole percent modifying diol residues having 3 to
16 carbons, wherein the total mole percent of diol residues is
equal to 100 mole percent; and wherein the total weight percent of
said polycarbonate (A) and polyester (B) is equal to 100 weight
percent.
[0083] The term "polyester," as used herein, is intended to include
"copolyesters" and is understood to mean a synthetic polymer
prepared by the polycondensation of one or more difunctional
carboxylic acids with one or more difunctional hydroxyl compounds.
Typically the difunctional carboxylic acid is a dicarboxylic acid
and the difunctional hydroxyl compound is a dihydric alcohol such
as, for example, glycols and diols. The term "residue," as used
herein, means any organic structure incorporated into a polymer or
plasticizer through a polycondensation reaction involving the
corresponding monomer. The term "repeating unit," as used herein,
means an organic structure having a dicarboxylic acid residue and a
diol residue bonded through a carbonyloxy group. Thus, the
dicarboxylic acid residues may be derived from a dicarboxylic acid
monomer or its associated acid halides, esters, salts, anhydrides,
or mixtures thereof. As used herein, therefore, the term
dicarboxylic acid is intended to include dicarboxylic acids and any
derivative of a dicarboxylic acid, including its associated acid
halides, esters, half-esters, salts, half-salts, anhydrides, mixed
anhydrides, or mixtures thereof, useful in a polycondensation
process with a diol to make a high molecular weight polyester.
[0084] Preferred polymer blends include at least one polyester(s)
(B) comprising dicarboxylic acid residues, diol residues, and,
optionally, branching monomer residues. The polyester(s) (B)
included in the present invention contain substantially equal molar
proportions of acid residues (100 mole %) and diol residues (100
mole %) which react in substantially equal proportions such that
the total moles of repeating units is equal to 100 mole %. The mole
percentages provided in the present disclosure, therefore, may be
based on the total moles of acid residues, the total moles of diol
residues, or the total moles of repeating units. For example, a
polyester containing 20 mole % isophthalic acid, based on the total
acid residues, means the polyester contains 20 mole % isophthalic
acid residues out of a total of 100 mole % acid residues. Thus,
there are 20 moles of isophthalic acid residues among every 100
moles of acid residues. In another example, a polyester containing
10 mole % ethylene glycol, based on the total diol residues, means
the polyester contains 10 mole % ethylene glycol residues out of a
total of 100 mole % diol residues. Thus, there are 10 moles of
ethylene glycol residues among every 100 moles of diol
residues.
[0085] Other polymer blends include polyester(s) (B) and
polycarbonates (A) that are miscible and which typically exhibit
only a glass transition temperature (T.sub.g) as a blend, as
measured by well-known techniques such as, for example,
differential scanning calorimetry. The polyesters utilized in the
present invention are amorphous or semi-crystalline and have glass
transition temperatures of about 40 to 140.degree. C., preferably
about 60 to 100.degree. C.
[0086] Suitable diacids include about 70 to 100 mole percent,
preferably 80 to 100 mole percent, more preferably, 85 to 100 mole
percent, even more preferably, 90 to 100 mole percent, and further
95 to 100 mole percent, of dicarboxylic acids, such as terephthalic
acid residues, isophthalic acids, or mixtures thereof. The
polyester may comprise about 70 to about 100 mole % of diacid
residues from terephthalic acid and 0 to about 30 mole % diacid
residues from isophthalic acid, alternatively about 0.1 to 30 mole
percent isophthalic acid.
[0087] Polyester (B) may further include from about 0 to about 30
mole percent, preferably 0 to 10 mole percent, and more preferably,
0.1 to 10 mole percent of the residues of one or more modifying
diacids (not terephthalic acid and/or isophthalic acid). Examples
of modifying diacids containing that may be used include but are
not limited to aliphatic dicarboxylic acids, alicyclic dicarboxylic
acids, aromatic dicarboxylc acids, or mixtures of two or more of
these acids. Specific examples of modifying dicarboxylic acids
include, but are not limited to, one or more of succinic acid,
glutaric acid, adipic acid, suberic acid, sebacic acid, azelaic
acid, dimer acid, sulfoisophthalic acid. Additional examples of
modifying diacids are fumaric, maleic, itaconic,
1,3-cyclohexanedicarboxylic, diglycolic,
2,5-norbornanedicarboxyclic, phthalic acid, diphenic,
4,4'-oxydibenzoic, and 4,4'-sulfonyldibenzoic. Other examples of
modifying dicarboxylic acid residues include but are not limited to
naphthalenedicarboxylic acid and 1,4-cyclohexanedicarboxylic acid.
Any of the various isomers of naphthalenedicarboxylic acid or
mixtures of isomers may be used, but the 1,4-, 1,5-, 2,6-, and
2,7-isomers are preferred. Cycloaliphatic dicarboxylic acids such
as, for example, 1,4-cyclohexanedicarboxylic acid may be present at
the pure cis or trans isomer or as a mixture of cis and trans
isomers. Dicarboxylic acids having 2 to 20 carbon atoms, preferably
2 to 18 carbon atoms, and more preferably, 2 to 16 carbon atoms,
are included in one embodiment of the invention.
[0088] The polyester (B) also comprises diol residues that may
comprise about 45 to about 95 mole percent of the residues of
1,4-cyclohexanedimethanol, 55 to about 5 mole percent of the
residues of neopentyl glycol, and 0 to 10 mole percent of one or
more modifying diol residues. As used herein, the term "diol" is
synonymous with the term "glycol" and means any dihydric
alcohol.
[0089] Alternatively, the blends typically include from about 1 to
99 weight percent, preferably 0.1 to 75 wt %, more preferably, 0.1
to 50 wt %, preferably 10 to 30 wt %, preferably 15 to 30 wt %, of
at least one polycarbonate (A) comprising: (1) a diol component
comprising about 90 to 100 mole percent 4,4'-isopropylidenediphenol
residues; and (2) about 0 to 10 mole percent modifying diol
residues; wherein the total mole percent of the diol residues is
equal to 100 mole percent; and comprise from about 99 to 1 weight
percent, preferably 99.9 to 25 weight percent, more preferably,
0.99.9 to 50 weight percent, and even more preferably, 75 to 50
weight percent of at least one polyester (B), wherein the total
weight percent of polycarbonate (A) and polyester (B) is equal to
100 weight percent.
[0090] Suitable polycarbonates are typically derived from bisphenol
A. Examples of suitable bisphenol A polycarbonates include the
materials marketed under the tradenames LEXAN, available from the
General Electric Company, and MAKROLON 2608, available from Bayer,
Inc. The polycarbonate portion of the blends preferably has a diol
component containing about 90 to 100 mole percent bisphenol A
units, and 0 to about 10 mole percent can be substituted with units
of other modifying aliphatic or aromatic diols, besides bisphenol
A, having from 2 to 16 carbons. The polycarbonate can contain
branching agents, such as tetraphenolic compounds,
tri-(4-hydroxyphenyl) ethane, and pentaerythritol triacrylate. It
is preferable to have at least 95 mole percent of diol units in the
polycarbonate being bisphenol A.
[0091] The above blends preferably include from about 10 to 90 wt %
of the polycarbonate component and 90 to about 10 wt % of the
polyester component. The composition may also include about 25 wt %
to 75 wt % polycarbonate and 75 wt % to 25 wt % polyester.
[0092] The intermediate layers of the golf balls of the present
invention are preferably formed from stiff thermoplastic
polyurethanes or polyureas. The molecular structure of a typical
thermoplastic urethane (TPU) consists of alternating high-melting
"hard" urethane segments and liquid-like "soft" segments.
[0093] Hard segments are typically the reaction product of an
aromatic or aliphatic diisocyanate and a low molecular weight,
chain-extending dialcohol or diol. Suitable diisocyanates include
alkyl diisocyanates, arylalkyl diisocyanates, cycloalkylalkyl
diisocyanates, alkylaryl diisocyanates, cycoalkyl diisicyanates,
arly diisocyanates, cycloalkylaryl diisocyanates, all of which may
be further substituted with oxygen, and mixtures thereof. The chain
extender of the hard segment used in the preparation of the
copolymers may be an aliphatic polyol or an aliphatic or aromatic
polyamine such as known for preparing polyurethanes and polyureas.
The polyol for the hard segment may be alkylene, cycloalkylene,
arylene diols, triols, tetraalcohols and pentaalcohols, and
mixtures thereof. The polyamine of the hard segment may be alkyl,
cycloalkyl, and aryl amines that may be further substituted with
nitrogen, oxygen, halogen, complexes thereof with alkali metal
salts and mixtures thereof.
[0094] The hard segment can be either aromatic or aliphatic.
Aromatic TPUs are commonly based on methylene diphenyl
4,4'-diisocyanate ("MDI") while aliphatic TPUs are commonly based
on dicyclohexylmethane diisocyanate ("H.sub.12MDI").
[0095] Soft segments may be built from polyols with terminal
hydroxyl (--OH) groups. The hydroxyl creates a urethane group,
while the reaction between isocyanates and existing urethane groups
will form allophanate groups that can produce minor amounts of
covalent cross-linking in TPUs. When a TPU is heated, the
hydrogen-bonded hard segments and any allophanate cross-links, both
of which hold the polymer together at its use temperature,
dissociate to allow the polymer to melt and flow. Dissolution in a
polar solvent can also disrupt the hydrogen bonds that hold
together the hard segments on adjacent chains. Once these virtual
cross-links are broken, the polymer can be fabricated into golf
balls. Upon cooling or solvent evaporation, the hard segments
de-mix from the soft segments to re-associate by hydrogen bonding.
This restores the original mechanical properties of the
polyurethane elastomer. Polyether and polycarbonate TPUs generally
have excellent physical properties, combining high elongation and
high tensile strength, albeit having fairly high-modulus. Varying
the hard segment of a TPU during synthesis can produce a whole
family of polymers of related chemistry but with a wide range of
hardness, modulus, tensile-strength properties and elongation. In
the fabrication of golf balls, the use of TPUs of different
hardness values within a single family provides considerable
versatility in manufacturing.
[0096] The molecular structure of a generic thermoplastic polyurea
consists of a rigid "hard segment" and a flexible "soft segment.
The hard segments are typically formed from the reaction product of
an aromatic or aliphatic diisocyanate with an aromatic or aliphatic
chain-extending diamine to form urea linkages. The soft segment may
be built from amine-terminated polyethers, polyesters,
polycaprolactones, polycarbonates, or other suitable long chain
backbone. The reaction product of the soft segment with the hard
segment, i.e., diisocyanates, produces urea linkages.
[0097] Other suitable TPUs include, but are not limited to,
silicone-urethane materials such as an aromatic or aliphatic
urethane hard segment with a silicone based soft segment to create
a thermoplastic silicone-urethane copolymer, combining the above
hard and soft segments with a polycarbonate to form a thermoplastic
silicone-polycarbonate urethane copolymer, or combining the above
hard and soft segments with a polyethylene oxide to form a
thermoplastic silicone-polyethyleneoxide urethane copolymer.
[0098] Thermoplastic silicone-polyether urethane copolymers
available today include PurSil.TM.; silicone-polycarbonate urethane
copolymers available include CarboSil.TM.; and
silicone-polyethylene oxide urethane copolymers include
Hydrosil.TM.. U.S. Pat. Nos. 5,863,627 and 5,530,083, which are
incorporated by reference herein in their entirety, describe how
PurSil.TM. CarboSil.TM. and Hydrosil.TM. are processed. The
thermoplastic elastomers containing silicone in the soft segment,
such as PurSil.TM., are prepared through a multi-step bulk
synthesis. In this synthesis the hard segment is an aromatic
urethane MDI (4,4'-diphenylmethane diisocynanate-butanediol) with a
low molecular weight glycol extender butanediol and the soft
segment is comprised of polytetramethylene oxide including
polydimethylsiloxane.
[0099] In addition to polydimethylsiloxane, other suitable
surface-modifying end groups, which may be used alone or in
combination with one another, include hydrocarbons, fluorocarbons,
fluorinated polyethers, polyalkylene oxides, various sulphonated
groups, and the like. Surface-modifying end groups are
surface-active oligomers covalently bonded to the base polymer
during synthesis. When the aromatic or aliphatic urethane hard
segment is combined with a hydrocarbon soft segment
surface-modifying end group, a hydrocarbon-polyurethane is produced
and has excellent properties for use in golf balls.
[0100] Thermoplastic polycarbonate-urethane copolymers are also
suitable materials for the intermediate layers of the present
invention and have good oxidative stability, excellent mechanical
strength, and abrasion resistance. Commercially-available
thermoplastic polycarbonate-polyurethane TPUs include, but are not
limited to, Bionate.RTM. polycarbonate-urethanes, such as
Bioante.RTM. 55D and 75D produced by the Polymer Technology Group
of Berkeley, Calif.
[0101] Bionate.RTM. polycabonate-urethane is a thermoplastic
elastomer formed as the reaction product of a hydroxyl terminated
polycarbonate, an aromatic diisocyanate, and a low molecular weight
glycol used as a chain extender. In a preferred embodiment,
polycarbonate glycol intermediate, poly (1,6-hexyl-1,2-ethyl
carbonate) diol, is the condensation product of 1,6-hexanediol with
cyclic ethylene carbonate. The polycarbonate macroglycol is reacted
with aromatic isocyanate, 4,4'-methylene bisphenyl diisocyanate,
and chain extended with 1,4-butanediol.
[0102] Ultimate tensile strengths for Bionate.RTM. compounds can
exceed 10,000 psi. The ultimate elongation of the present invention
is about 20 to 1000% with a preferred elongation of at least about
400 to about 800%. The initial modulus of the materials suitable
for the present invention is about 300 to 150,000 psi, and
preferably between about 10,000 and about 80,000 psi. Other
suitable commercially-available TPUs include the E-Series TPUs,
such as D 60 E 4024 from Huntsman Polyurethanes of Germany, and
TPUs sold under the tradenames of Texin.RTM. 250, Texin.RTM. 255,
Texin.RTM. 260, Texin.RTM. 270, Texin.RTM. 950U, Texin.RTM.
DP7-1202, Texin.RTM. 970U, Texin.RTM. 3203, Texin.RTM. 4203,
Texin.RTM. 4206, Texin.RTM. 4210, Texin.RTM. 4215, and Texin.RTM.
3215, and Desmopan.RTM. 453 from Bayer of Pittsburgh, Pa.
[0103] U.S. Pat. Nos. 6,855,793, 6,739,987, and 7,037,217 disclose
preferred polycarbonate-polyurethane copolymers,
silicone-polyurethane copolymers, and silicone-polyurethanes,
respectively, the disclosures of which are incorporated herein, in
their entirety, by reference thereto.
[0104] The TPUs (both thermoplastic polyurethanes and thermoplastic
polyureas) of the invention are also readily blended with other
thermoplastic polymers, such as polycarbonates, polyvinyl
chlorides, acrylonitrile-butadiene-styrenes, and polyamides. Any
TPU blend, alloy or copolymer, is also suitable for the
intermediate layers of the invention, such as TPU/polycarbonates;
TPU/ABS; TPU/SMA (styrene-maleic anhydride); TPU/styrene-butadiene
or styrene-ethylene-butadiene block copolymers; TPU/polyolefins,
such as polypropylene, polyethylene, ethylene-propylene rubber
("EPR"), ethylene-propylene-diene monomer ("EPDM"), and
ethylene-vinyl acetate; or TPU/modified polyolefins, such as DuPont
Fusabond.RTM. functionalized (typically by maleic anhydride
grafting) metallocene-catalyzed polyolefins or any other
polar-group modified ethylene copolymer, such as Dow Amplify.RTM.
IO, GR, or EA grade polymers.
[0105] Thermoplastic transparent polyamides are also suitable
materials for use in the intermediate (or inner cover) layers of
the invention. These compositions comprise at least one transparent
polyamide. The transparent polyamide by itself, may comprise a
homopolymer, copolymers including block copolymer, or a blend or
alloy thereof. In one preferred embodiment, the composition
comprises an acid anhydride-modified polyolefin and/or plasticizer,
as discussed below.
[0106] The term "polymer" refers to, but is not limited to,
oligomers, homopolymers, copolymers, terpolymers, and the like. The
polymers may have various structures including, but not limited to,
regular, irregular, alternating, periodic, random, block, graft,
linear, branched, isotactic, syndiotactic, atactic, and the like.
Polyamide polymers include, but are not limited to, polyamide
copolymers (copolyamides) having two types of monomers, copolymers
having three types of monomers, and copolymers having more than
three types of monomers. Blends and alloys of polyamides also may
be made in accordance with this invention as described further
below.
[0107] The term "transparent," as it relates to the polyamides
herein, describes a material having a light transmission of 50% or
greater, as measured with test procedure ISO 13468 using a 2-mm
thick sample measured at a wavelength of 560 nm. In general,
transparent polyamides are classified as having a microcrystalline
structure or amorphous structure. Both microcrystalline and
amorphous transparent polyamides may be used in the present
invention. It should be understood that while a transparent
polyamide is preferably included in the composition, the final
composition may have a transparent, translucent, or opaque optical
nature. The final composition may contain various additives
including fillers, coloring agents, dyes, pigments, and the like,
that effect the optical nature of the composition. The term
"translucent," as it relates to the polyamides herein, describes a
material having a light transmission of 1-49%, as measured with
test procedure ISO 13468 using a 2-mm thick sample measured at a
wavelength of 560 nm. The transparent polyamides of the present
invention preferably have a light transmission lower limit of about
50% or greater, more preferably 54%, 58%, 60%, 65%, 68% or 70% or
greater, and an upper limit of 100% or less, more preferably 95%,
94%, 92%, 90%, 84%, 80%, or 75% or less, as measured with test
procedure ISO 13468 using a 2-mm thick sample measured at a
wavelength of 560 nm.
[0108] Commercially-available transparent polyamides include, but
are not limited to, copolyamides such as PLATAMID.RTM. 8020;
semi-aromatic transparent polyamides such as RILSAN.RTM. Clear
G170; transparent polyamides such as RILSAN.RTM. G120 Rnew;
RILSAN.RTM.G830 Rnew and G830 L Rnew; RILSAN.RTM. G850; RILSAN.RTM.
Clear G350 and G350L; RILSAN.RTM. G300 HI; and transparent
polyamides that are partly based on bio-based raw materials such as
RILSAN.RTM. Clear G830, all of which are available from Arkema,
Inc. of King of Prussia, Pa., may be used. Other suitable examples
include ULTRAMID.RTM. polyamides, available from BASF; and
ZYTEL.RTM. and DARTEK.RTM. nylon resins, available from DuPont.
EMS-Chemie AG of Switzerland supplies different grades of
transparent polyamides under the Grilamid mark, including;
GRILAMID.RTM. TR 30, TR55, TR90, XE 3997, XE 4028 grades, and these
polyamides may be used per this invention. GRIVORY.RTM. G and GTR
transparent polyamides also are available from EMS-Chemie AG and
may be used in the compositions of this invention. Other suitable
polyamides include TROGAMID.RTM. and VESTAMID.RTM. grades available
from DeGussa AG of Marl, Germany; KOPA.RTM. grades available from
Kolon; DUREATHAN.RTM. grades available from Lanxess AG of Cologne,
Germany; ARLEN.RTM. grades available from Mitsui Japan; transparent
amorphous nylons such as ASHLENE.RTM. D870 and D870L available from
Ashley Polymers of Brooklyn, N.Y.; RADICI RADILON.RTM. CST
copolyamides; Shakespeare ISOCOR.RTM. CN30XT and CN30BT NYLON 610
resins by Jarden Applied Materials of Columbia, S.C.; Toyobo
GLAMIDE.RTM. T-714E nylons; and TP Composites ELASTOBLEND.RTM. PAl2
CL nylons. Transparent polyamides including, but not limited to,
polyether-amide, polyester-amide, polyether-ester-amide block
copolymers, are particularly suitable for use in the invention
herein, and more particularly, the transparent polyamide
copolymers, RILSAN.RTM. Clear G300 HI, PEBAX.RTM. Clear 300, and
PEBAX.RTM. Clear 400 available from Arkema, Inc. of King of
Prussia, Pa., are particularly effective.
[0109] Examples of transparent polyamides that may be used in the
intermediate layers of the present invention also are described in
the patent literature. For example, transparent homopolyamides and
copolyamides which are amorphous or which exhibit a slight
crystallinity such as those described in U.S. Patent Application
Publication No. 2010/0140846; and U.S. Pat. Nos. 6,376,037 and
8,399,557. Also, amorphous transparent or translucent polyamides
that may be formed from the condensation of diamines with
dicarboxylic acids or lactams; and blends or alloys of two or more
different polyamides, as described in U.S. Patent Application
Publication No. 2012/0223453, may be used. Polyamide copolymers
such as a copolymers containing polyether blocks and polyamide
blocks as described in U.S. Patent Application Publication No.
2013/0202831, may be used. The polyamide copolymers described in
the '831 Publication are resistant to a high-velocity impact of at
least 76.2 m/s (250 ft/s) according to the EN 166 standard, have a
Charpy notched impact strength of at least 90 kJ/m2 according to
the ISO 179 leU standard, and preferably have a chemical resistance
such that they are capable of deforming, in flexion, by immersion
in a solvent according to the ISO 22088-3 standard by at least 3%
without breaking; that is light, having a density of less than 1.05
g/cm.sup.3 measured according to the ISO 1183 D standard; and that
is flexible and has an elastic modulus of less than 1000 MPa,
preferably of less than 800 MPa, measured according to the ISO
527-2:93-1BA standard. The disclosures of these patent and
publications are incorporated herein by reference
[0110] Transparent polyamides that may be used in accordance with
this invention also include those polyamides described in U.S. Pat.
Nos. 6,528,560; 6,831,136; 6,943,231; 8,309,643; and 8,507,598; and
U.S. Patent Application Publication No. 2010/0203275, the
disclosures of which are hereby incorporated by reference.
[0111] In general, polyamides refer to high molecular weight
polymers in which amide linkages (--CONH--) occur along the length
of the molecular chain. Suitable polyamides for use in the
intermediate layer compositions of the invention may be obtained,
for example, by: (1) polycondensation of (a) a dicarboxylic acid,
such as oxalic acid, adipic acid, sebacic acid, terephthalic acid,
isophthalic acid or 1,4-cyclohexanedicarboxylic acid, with (b) a
diamine, such as ethylenediamine, tetramethylenediamine,
pentamethylenediamine, hexamethylenediamine, or
decamethylenediamine, 1,4-cyclohexyldiamine or m-xylylenediamine;
(2) a ring-opening polymerization of cyclic lactam, such as
.epsilon.-caprolactam or .omega.-laurolactam; (3) polycondensation
of an aminocarboxylic acid, such as 6-aminocaproic acid,
9-aminononanoic acid, 11-aminoundecanoic acid or 12-aminododecanoic
acid; or (4) copolymerization of a cyclic lactam with a
dicarboxylic acid and a diamine. Specific examples of suitable
polyamides include, but are not limited to, Nylon 6, Nylon 6,6;
Nylon 6,10; Nylon 11, and Nylon 12. Aliphatic and aromatic
polyamides and blends thereof may be prepared in accordance with
this invention.
[0112] In general, polyamide homopolymers and copolymers are
suitable for use in this invention. The specific monomers, reaction
conditions, and other factors will be selected based on the desired
polyamide polymer to be produced. There are two common methods for
producing polyamide homopolymers. In a first method, a compound
containing one organic acid-type end group and one amine end group
is formed into a cyclic monomer. The polyamide is then formed from
the monomer by a ring-opening polymerization.
[0113] The second method involves the condensation polymerization
of a dibasic acid and a diamine. In general, this reaction takes
place as follows:
##STR00001##
[0114] Suitable polyamides include NYLON.RTM. 4, NYLON.RTM. 6,
NYLON.RTM. 7, NYLON.RTM. 11, NYLON.RTM. 12, NYLON.RTM. 13,
NYLON.RTM. 4,6; NYLON.RTM. 6,6; NYLON.RTM. 6,9, NYLON.RTM. 6,10;
NYLON.RTM. 6,12; NYLON.RTM. 12,12; NYLON.RTM. 13,13; and mixtures
thereof. More preferred polyamides include NYLON.RTM. 6, NYLON.RTM.
11, NYLON.RTM. 12, NYLON.RTM. 4,6; NYLON.RTM. 6,6; NYLON.RTM. 6,9;
NYLON.RTM. 6,10; NYLON.RTM. 6,12; NYLON.RTM. 6/66; and NYLON.RTM.
6/69 and mixtures thereof.
[0115] Compositions of NYLON.RTM. 6, NYLON.RTM. 6,6; NYLON.RTM. 11,
and NYLON.RTM. 12 and copolymers and blends thereof are suitable in
the present invention. More specifically, polyamide compositions
having mechanical properties that do not significantly change after
the composition has been exposed to moisture are particularly
effective.
[0116] More particularly, as noted above, transparent polyamides
are particularly suitable for use in the invention herein. Such
transparent polyamides include transparent polyamide copolymers
(copolyamides). For example, polyether-amide and polyester-amide
block copolymers may be used. Such polyamide copolymers are
described, for example, in the above-mentioned U.S. Patent
Application Publication No. 2010/0140846; and U.S. Pat. Nos.
6,376,037 and 8,399,557. It should be understood that the term,
"polyamide," as used in the present invention, is meant to include
copolymers with polyamide blocks and polyether blocks, i.e.,
polyether block amide polymers, and the mixtures of these
copolymers with the preceding polyamides. Polymers with polyamide
blocks and polyether blocks result from the copolycondensation of
polyamide sequences comprising reactive ends with polyether
sequences comprising reactive ends, such as: a) polyamide sequences
comprising diamine chain ends with polyoxyalkylene sequences
comprising dicarboxylic chain ends, b) polyamide sequences
comprising dicarboxylic chain ends with polyoxyalkylene sequences
comprising diamine chain ends obtained by cyanoethylation and
hydrogenation of a .OMEGA.-dihydroxylated aliphatic polyoxyalkylene
sequences, known as polyetherdiols, or c) polyamide sequences
comprising dicarboxylic chain ends with polyetherdiols, the
products obtained being, in this specific case,
polyetheresteramides.
[0117] These polymers with polyamide blocks and polyether blocks,
whether they originate from the copolycondensation of polyamide and
polyether sequences prepared beforehand or from a one-stage
reaction, exhibit, for example, Shore D hardness values that can be
from 20 to 95 and advantageously between 25 and 85, more preferably
30 to 80, and even more preferably 35 to 78 and an intrinsic
viscosity between 0.8 and 2.5, measured in meta-cresol at
25.degree. C.
[0118] Whether the polyester blocks derive from polyethylene
glycol, polyoxypropylene glycol or polyoxytetramethylene glycol,
they are either used as is and copolycondensed with polyamide
blocks comprising carboxylic ends or they are aminated, in order to
be converted into polyetherdiamines, and condensed with polyamide
blocks comprising carboxylic ends. They can also be mixed with
polyamide precursors and a chain-limiting agent in order to form
polymers with polyamide blocks and polyether blocks having
statistically distributed units. Polymers with polyamide and
polyether blocks are disclosed in U.S. Pat. Nos. 4,331,786;
4,115,475; 4,195,015; 4,839,441; 4,864,014; 4,230,838; and
4,332,920, the disclosures of which are incorporated herein by
reference. The polyether can be, for example, a polyethylene glycol
(PEG), a polypropylene glycol (PPG) or a polytetramethylene glycol
(PTMG).
[0119] Blends of polyamides also may be used in accordance with
this invention. For example, a blend of transparent polyamides or a
blend of transparent and non-transparent polyamides may be used in
accordance with this invention. In particular, a blend of
transparent polyamide and a thermoplastic polyamide elastomer
(typically a copolymer of polyamide and polyester/polyether) may be
used. The polyamide elastomer may be transparent or
non-transparent. Many polyamide elastomers comprise a hard
polyamide segment (for example, NYLON.RTM. 6, NYLON.RTM. 6,6;
NYLON.RTM. 11, NYLON.RTM. 12 and the like) and a polyether or
polyester as a soft segment. Suitable polyamide elastomers that can
be used to form the compositions of this invention include, for
example. polyether-amide block copolymers, available from Arkema,
Inc. of Columbs, France as PEBAX.RTM. resins. In general, these
block copolymers have thermoplastic properties and elastomeric
properties.
[0120] In a particularly preferred version, blends of polyamide
polymers as described in above-mentioned U.S. Pat. No. 8,399,557,
are used to form the compositions of this invention. These
transparent blends comprise, by weight, the total being 100%: (A) 1
to 99% of at least one constituent copolymer: exhibiting a high
transparency such that the transmission at 560 nm through a sheet
with a thickness of 2 mm is greater than 65%; exhibiting a glass
transition temperature of at least 90.degree. C.; and being
amorphous or exhibiting a crystallinity ranging up to
semicrystallinity; and comprising: (A1) amide units, including
amide units produced from at least one cycloaliphatic diamine unit;
and (A2) flexible ether units; (B) 99 to 1% of at least one
constituent polymer chosen from: (Ba) semicrystalline copolyamides
comprising amide units (Ba1) and comprising ether units (Ba2),
wherein said semicrystalline copolyamides have a glass transition
temperature (Tg) of less than 65.degree. C.; and alloys based on
such copolyamides (Ba); and (C) 0 to 50% by weight of at least one
polyamide, copolyamide, or copolyamide comprising ether units other
than those used in (A) and (B) above; and/or of at least one
additive normal for thermoplastic polymers and copolymers; the
choice of the units or monomers in the composition of (A), (B) and
(C) and also the choice of the proportions of the said units or of
the said monomers being such that the resulting blend or alloy
exhibits a high transparency such that the transmission at 560 nm
through a sheet with a thickness of 2 mm is greater than 50%.
[0121] The reaction products of the above-described components (A),
(B), and (C), also may be used to form a polyamide composition
suitable for use in the present invention.
[0122] One advantageous property of the transparent polyamides used
to form the compositions of the present invention is that they
exhibit a relatively high glass transition temperature (Tg). The
transparent polyamides are relatively easy to process and can be
molded to form different golf ball layers. The Tg, as reported
herein, is measured according to Test Method ISO 11357 and reported
in .degree. C. As the temperature of a polymer drops below the Tg,
it behaves in an increasingly brittle manner. As the temperature
rises above the Tg, the polymer becomes more rubber-like. Knowledge
of Tg, therefore, is an important factor in the selection of
materials for golf ball layer applications. In general, values of
Tg well-below room temperature define the domain of elastomers and
Tg values above room temperature define rigid, structural polymers.
It has been found that preferred transparent polyamides exhibit a
Tg in a range of about 30.degree. C. to about 170.degree. C., and
has a lower range of about 35.degree. C., 40.degree. C., 50.degree.
C., or 60.degree. C. and an upper range of about 70.degree. C.,
80.degree. C., 90.degree. C., 120.degree. C., 140.degree. C., or
150.degree. C. In one preferred version, the Tg may be about
65.degree. C., 75.degree. C., 85.degree. C., 91.degree. C.,
95.degree. C., or 105.degree. C. In an alternative embodiment, the
transparent polyamide has a Tg in the range of about 75.degree. C.
to about 160.degree. C., more preferably in the range of about
80.degree. C. to about 95.degree. C.
[0123] As used herein, the term "semi-crystalline" covers
polyamides which have both a Tg and a melting point as determined
by DSC. The term "amorphous" covers polyamides that do not have a
melting point detected by DSC or a melting point with negligible
intensity such that it does not affect the essentially amorphous
nature of the polymer. The term "semi-crystalline," as used herein,
relates to polymers that have both a melting exotherm and a glass
transition as determined by DSC. The term "amorphous," as used
herein, relates to polymers that have a glass transition but either
do not exhibit a melting exotherm or exhibit a glass transition and
a small or insignificant melting exotherm (DH.sub.f.ltoreq.10 J/g)
as determined by DSC. The term, "micro-crystalline," as used
herein, refers to semi-crystalline polymers in which the melting
exotherm is determined by DSC. The term, "quasi-amorphous," as used
herein, relates to polymers that the spherulite size is
sufficiently small in order to maintain transparency.
[0124] The transparent polyamides also have high flexibility,
toughness, impact-durability and stress-crack resistance. One
advantageous property of the transparent polyamides used to form
the compositions of the present invention is their relatively high
Charpy impact-resistance. In general, impact testing refers to the
energy required to break or deform a material. The Charpy impact
test is a standardized high strain-rate test which determines the
amount of energy absorbed by a material during fracture. This
absorbed energy is a measure of a given material's notch toughness
and acts as a tool to study temperature-dependent ductile-brittle
transition. The test method standard is ISO 179/1eA. Samples are
conditioned for 15 days at 23.degree. C. and 50% relative humidity.
The test results herein are measured at either 23.degree. C. or
-30.degree. C. and results are reported in kilojoules per meter
squared. The higher the number, the tougher the material, with a
no-break (NB) meaning that the test sample was flexible enough to
withstand the impact without fracturing. High Charpy impact values
are an important material property to consider when choosing a
material for a layer in a golf ball, since a golf ball must
withstand very high force impacts, such as those encountered when
struck with a golf club. It is believed that the polyamide
compositions herein comprising a transparent polyamide, preferably
have a Charpy notched impact (at 23.degree. C.) of from at least
about 8 to No-Break (NB), and have a lower range of from about 10,
12, 14, 16, 18, 25, 30, or 40 kJ/m.sup.2 to an upper limit ranging
from about 80, 85, 90, or 94 kJ/m.sup.2 to no-break. A preferred
transparent polyamide composition comprises Rilsan Clear G300 HI,
which has a Charpy notched impact value at 23.degree. C. of 94
kJ/m.sup.2, and a value at -30.degree. C. of 19 kJ/m.sup.2.
[0125] The polyamide compositions of this invention may further
contain acid anhydride-modified polyolefins. Adding the acid
anhydride-modified polyolefin helps improve the toughness and
impact durability of the composition. In such materials, the
polyolefin polymer is chemically modified with acid anhydride. That
is, the polyolefin polymer is functionalized; it contains at least
one acid anhydride group. In general, such acid anhydride groups
may be grafted onto the polyolefin polymer backbone. Some examples
of suitable acid anhydrides that may be used to functionalize the
polyolefin include, but are not limited to, fumaric, nadic,
itaconic, and clorendic anhydrides, and their substituted
derivatives thereof.
[0126] Suitable olefin monomeric units that can be used to prepare
the polyolefin polymer include, for example, ethylene, propylene,
butene, hexene, heptene, octene, decene, and dodecene. Preferably,
the monomeric unit contains from 2 to about 20 carbon atoms. The
resulting polyolefin chains (polymer backbones) formed from these
monomeric units include, for example, polyethylene, high density
polyethylene (HDPE), low density polyethylene (LDPE), very low
density polyethylene (VLDPE), polypropylene, polybutene,
polyhexene, polyoctene, polydecene, and polydodecene, and
copolymers and blends thereof. The resulting polyolefin polymer is
functionalized with at least one acid anhydride moiety.
[0127] More particularly, the acid anhydride-modified polyolefin
polymers used in this invention include copolymers such as, for
example, ethylene-based copolymers, particularly ethylene-propylene
(EP); ethylene-butene (EB); ethylene-hexene (EH); ethylene-octene
(EO); styrene-ethylene/butylene-styrene (SEBS); ethylene-propylene
diene monomer (EPDM); ethylene-vinyl acetate (EVA); and various
ethylene-alkyl acrylate and ethylene-alkyl alkyl acrylate
copolymers such as, for example, ethylene-methyl acrylate (EMA);
ethylene-ethyl acrylate (EEA); ethylene-propyl acrylate (EPA);
ethylene n-butyl acrylate (EBA) copolymers; and the like. Other
polyolefin-based copolymers such as polypropylene and
polybutene-based copolymers also can be used. These copolymers
include random, block, and graft copolymers which have been
functionalized with acid anhydride groups.
[0128] Examples of commercially-available acid anhydride
polyolefins that can be used in accordance with this invention,
include, but are not limited to, AMPLIFY.RTM. GR functional
polymers, available from the Dow Chemical Company; FUSABOND.RTM.
polymers, available from the DuPont Company; KRATON.RTM. FG and RP
polymers, available from Kraton Polymers LLC; LOTADER.RTM. polymers
available from Arkema, Inc.; POLYBOND.RTM. and ROYALTUF.RTM.
polymers, available from Chemtura Corp.; and EXXELOR.RTM. polymers
available from the ExxonMobil Corp.
[0129] Various polyamide compositions may be made in accordance
with this invention. The composition may optionally contain an acid
anhydride-modified polyolefin, plasticizer, fatty acid salt, fatty
acid amide, fatty acid ester, and mixtures thereof. The resulting
polyamide composition may be used to prepare a golf ball component
(for example, core, casing, or cover layer) having several
advantageous properties.
[0130] As noted above, it is significant that a blend comprising
transparent polyamide and acid anhydride-modified polyolefin may be
prepared. For example, a blend of 90% GRIVORY.RTM. GTR45
transparent polyamide and 10% FUSABOND.RTM. N525 acid
anhydride-modified polyolefin may be prepared and the resulting
composition (solid sphere) has a COR of 0.784, Atti compression of
182, and Shore D surface hardness of 81.8. In another example, a
blend of 50% GRIVORY.RTM. GTR45 transparent polyamide and 50%
FUSABOND.RTM. N525 acid anhydride-modified polyolefin may be
prepared and the resulting composition (solid sphere) has a COR of
0.633, Atti compression of 105, and Shore D surface hardness of
56.2.
[0131] In other embodiments, it is not necessary for the polyamide
to be blended with an acid anhydride-modified polyolefin or any
other polymer or non-polymer material. That is, the composition may
consist entirely of the transparent polyamide. In other instances,
the composition may include transparent polyamide at 97 to 100% by
weight. In one particular version, the composition comprises
transparent polyether-amide block copolymer such as the
above-mentioned RILSAN.RTM. G300 HI, PEBAX.RTM. Clear 300, or
PEBAX.RTM. Clear 400 (Arkema, Inc.).
[0132] The polyester-containing compositions disclosed herein may
be used in one or more core, intermediate or cover layers. For
instance, the compositions may be used in an innermost core or
center layer, and intermediate core layer or in an outermost core
layer. Further the layer may be an inner, intermediate or outermost
cover layer. For example in a golf ball having a three-layered
cover, the polyester-containing composition may be used in any of
the three layers, but preferably is used in the inner or
intermediate cover layer, or both. The polyester-comprising
compositions are thermoplastic compositions and may be adjacent to
another thermoplastic composition or may be adjacent to a
thermosetting composition. For example, in a three (3) or more
layered-core construction, the center may be a thermosetting rubber
composition, an intermediate core layer may comprise a
polyester-based composition, and the outer core layer may be made
from a thermosetting rubber composition. Alternatively, the center
and intermediate core layer may comprise a thermosetting rubber and
the outer core layer comprises the thermoplastic polyester-based
composition, and the like. In a two-piece construction comprising a
core and a cover, either the core or cover or both layers may
consist of the polyester-containing composition.
[0133] As discussed above, polyester-based thermoplastic elastomers
may be used to form the compositions of this invention. In general,
"thermoplastic elastomers" refer to a class of polymers having
thermoplastic-like (softens when exposed to heat and returns to
original condition when cooled) properties and elastomeric-like
(can be stretched and then returns to original condition when
released) properties. In thermoplastic elastomer block copolymers,
there are some blocks having thermoplastic-like properties and
these blocks may be referred to as "hard" segments. Also, there are
some blocks having elastomeric-like properties and these blocks may
be referred to as "soft" segments. The ratio of hard to soft
segments and the composition of the segments are significant
factors in determining the properties of the resulting
thermoplastic elastomer.
[0134] One example of a suitable polyester thermoplastic elastomer
that can be used to form the compositions of this invention is
polyester-polyether block copolymers. In general, these block
copolymers contain hard and soft segments having various lengths
and sequences. The hard, crystalline polyester segments are
normally derived from reacting an aromatic-containing dicarboxylic
acid or diester such as, for example, terephthalic acid, dimethyl
terephthalate, and the like with a diol containing about 2 to about
10 carbon atoms. For example, the hard segments may constitute
butylene terephthalate, tetramethylene terephthalate, or ethylene
terephthalate units. The soft, elastomeric segments are normally
derived from long or short-chain poly(alkylene oxide) glycols
containing a total of about 3 to about 12 carbon atoms including up
to 3 or 4 oxygen atoms with the remaining atoms being hydrocarbon
atoms. Useful poly(alkylene oxide) glycols include, for example,
poly(oxyethylene) diol, poly(oxypropylene) diol, and
poly(oxytetramethylene) diols. More particularly, the polyether
polyols have been based on polymers derived from cyclic ethers such
as ethylene oxide, 1,2-propylene oxide and tetrahydrofuran. When
these cyclic ethers are subjected to ring opening polymerization,
they provide the corresponding polyether glycol, for example,
polyethylene ether glycol (PEG), poly(1,2-propylene) glycol (PPG),
and polytetramethylene ether glycol (PO4G, also referred to as
PTMEG).
[0135] One preferred polyester thermoplastic elastomer is
RITEFLEX.RTM. material, available from Ticona-Celanese Corp. The
RITEFLEX.RTM. TPC-ET products include different grades of
polyester-polyether block copolymers, and examples of such
materials and their respective properties are described in below
TABLE I. Another preferred polyester-polyether block copolymer is
commercially-available under the trademark, HYTREL.RTM., from
DuPont. The HYTREL.RTM. polyester block copolymers are available in
different grades and contain hard (crystalline) segments of
polybutylene terephthalate and soft (amorphous) segments based on
long-chain polyether glycols. These and other examples of
polyester-polyether block copolymers which can be used in
accordance with the present invention are disclosed in U.S. Pat.
Nos. 2,623,031; 3,651,014; 3,763,109; and 3,896,078, the
disclosures of which are hereby incorporated by reference.
Different grades of HYTREL.RTM. polyester-polyether block
copolymers and their respective properties, which may be used in
accordance with this invention, are described in the following
TABLES II and III.
TABLE-US-00001 TABLE I Properties of RITEFLEX .RTM. Polyester Block
Copolymers Test RITEFLEX .RTM. Grade Property Method Units 425 440
640A 663 677 hardness ISO 868 D 24 38 40 63 75 flex modulus ISO 178
at -40.degree. C. MPa 162 270 115 1900 2500 at 23.degree. C. 17 45
70 325 650 at 100.degree. C. 8 28 32 150 240 tensile stress at
break ISO 527 MPa 10 18 17 38 42 elongation at break ISO 527 %
>500 >500 >500 >450 >300 Izod impact ISO180 at
-40.degree. C. kj/m.sup.2 no break no break no break 7c 4.7c at
23.degree. F. no break no break no break 74p 8.5 melt flow rate
ISO1133 g/10 13(190.degree. C.) 13(220.degree. C.) 10(220.degree.
C.) 19(240.degree. C.) 15(240.degree. C.) min temp at 2.16-kg load
.degree. C. melting point ISO11357 .degree. C. 155 195 170 212 218
Vicat softening pt. ISO 306 .degree. C. 61 127 119 194 213 s.g. ISO
1183 g/cm.sup.3 1.06 1.11 1.13 1.24 1.27
TABLE-US-00002 TABLE II Properties of HYTREL .RTM.
Polyester-polyether Block Copolymers Test HYTREL .RTM. Grade
Property Method Units F3548L G4074 G4778 G5544 4056 hardness D 2240
D 35 40 47 55 40 flex modulus D790 at -40.degree. C. method kpsi 9
30 47 123 22.5 I at 73.degree. F. Proc B kpsi 4.7 9.5 17 28 9 at
212.degree. F. kpsi 1 4.75 10 18 3.9 tensile stress at break D 638
kpsi 1.49 2 3 4.5 4.05 elongation at break D638 % 200 230 300 375
550 Izod impact D256 at -40.degree. C. method ft no 0.5 3.1 2.5 no
A lb/in break break at 73.degree. F. ft no no no no no lb/in break
break break break break melt flow rate D1238 g/10 10 5.2 13 10 5.3
min temp at 2.16-kg load .degree. F. 374 374 446 446 374 melting
point D3418 .degree. F. 312 338 406 419 302 Vicat softening pt.
D1526 .degree. F. 171 233 347 385 226 Rate B s.g. D792 1.15 1.18
1.2 1.22 1.17
TABLE-US-00003 TABLE III Properties of HYTREL .RTM.
Polyester-polyether Block Copolymers Test HYTREL .RTM. Grade
Property Method Units 4556 6356 7246 8238 3078 hardness D 2240 D 45
63 72 82 30 flex modulus D790 at -40.degree. C. method kpsi 33 260
350 440 21 I at 73.degree. F. Proc B kpsi 14 48 83 175 4 at
212.degree. F. kpsi 6.4 22 30 37 2 tensile stress at break D 638
Ksi 4.5 6 6.6 7 5.8 elongation at break D638 % 600 420 360 350 450
Izod impact D256 at -40.degree. C. method ft no 0.9 0.8 0.5 No A
lb/in break break at 73.degree. F. no no 3.9 0.8 No break break
break melt flow rate D1238 g/10 8.5 8.5 12.5 12.5 5 min Temp at
2.16-kg load 428 446 464 464 374 melting point D3418 .degree. F.
379 412 424 433 338 Vicat softening pt. D1526 .degree. F. 171 383
405 414 181 Rate B s.g. D792 1.14 1.22 1.25 1.28 1.07
[0136] As shown in above TABLES II and III, the flex modulus of
some HYTREL.RTM. polyester-polyether block copolymers may fall
within the range of about 1,000 to about 150,000 psi (or greater).
Such block copolymers may be used to form a low modulus (or high
modulus) core layer in accordance with this invention.
[0137] Blends of polyesters and blends of polyesters with other
polymers may be used in accordance with this invention. For
example, the polyester thermoplastic elastomer may be blended with
other thermoplastics such as polyamides. Various plasticizers may
be used in the polyester-based thermoplastic composition, and these
plasticizers are discussed further below. Suitable polyamide
elastomers that can be used to form the compositions of this
invention include, for example. polyether-amide block copolymers,
available from Arkema, Inc. (Columbs, France) as Pebax.RTM. resins.
Other suitable polyamides include nylon 4, NYLON.RTM. 6, NYLON.RTM.
7, NYLON.RTM. 11, NYLON.RTM. 12, NYLON.RTM. 13, NYLON.RTM. 4,6;
NYLON.RTM. 6,6; NYLON.RTM. 6,9, NYLON.RTM. 6,10; NYLON.RTM. 6,12;
NYLON.RTM.12,12; NYLON.RTM. 13,13; and mixtures thereof. More
preferred polyamides include NYLON.RTM. 6, NYLON.RTM. 11,
NYLON.RTM. 12, NYLON.RTM. 4,6; NYLON.RTM. 6,6; NYLON.RTM. 6,9;
NYLON.RTM. 6,10; NYLON.RTM. 6,12; NYLON.RTM. 6/66; and NYLON.RTM.
6/69 and mixtures thereof.
[0138] The polyamide or polyester compositions (and blends thereof)
of this invention may further contain a plasticizer. Adding the
plasticizers to the composition helps to reduce the Tg of the
composition. In addition to lowering the Tg, the plasticizer may
also reduce the tan 6 in the temperature range above the Tg. Tan 6
is measured by a Dynamic Mechanical Analyzer (DMA). The plasticizer
may also reduce the hardness and compression of the composition
when compared to its non-plasticized condition.
[0139] Adding the plasticizers to the composition also helps
decrease the stiffness of the composition. That is, the plasticizer
helps lower the flex modulus of the composition. The flex modulus
refers to the ratio of stress to strain within the elastic limit
(when measured in the flexural mode) and is similar to tensile
modulus. This property is used to indicate the bending stiffness of
a material. The flexural modulus, which is a modulus of elasticity,
is determined by calculating the slope of the linear portion of the
stress-strain curve during the bending test. If the slope of the
stress-strain curve is relatively steep, the material has a
relatively high flexural modulus meaning the material resists
deformation. The material is more rigid. If the slope is relatively
flat, the material has a relatively low flexural modulus meaning
the material is more easily deformed. The material is more
flexible. The flex modulus can be determined in accordance with
ASTM D790 standard among other testing procedures.
[0140] The polyamide or polyester compositions may contain one or
more plasticizers. The plasticizers that may be used in the
polyamide compositions of this invention include, for example,
N-butylbenzenesulfonamide (BBSA); N-ethylbenzenesulfonamide (EBSA);
N-propylbenzenesulfonamide (PBSA);
N-butyl-N-dodecylbenzenesulfonamide (BDBSA);
N,N-dimethylbenzenesulfonamide (DMBSA); p-methylbenzenesulfonamide;
o,p-toluene sulfonamide; p-toluene sulfonamide;
2-ethylhexyl-4-hydroxybenzoate; hexadecyl-4-hydroxybenzoate;
1-butyl-4-hydroxybenzoate; dioctyl phthalate; diisodecyl phthalate;
di-(2-ethylhexyl) adipate; and tri-(2-ethylhexyl) phosphate.
[0141] Other suitable plasticizer compounds include benzene mono-,
di-, and tricarboxylic acid esters. Phthalates such as
bis(2-ethylhexyl) phthalate (DEHP), diisononyl phthalate (DINP),
di-n-butyl phthalate (DBP), butyl benzyl phthalate (BBP),
diisodecyl phthalate (DIDP), dioctyl phthalate (DnOP), diisooctyl
phthalate (DIOP), diethyl phthalate (DEP), diisobutyl phthalate
(DIBP), and di-n-hexyl phthalate are suitable. Iso- and
terephthalates such as dioctyl terephthalate and dinonyl
isophthalate may be used. Also appropriate are trimellitates, such
as trimethyl trimellitate (TMTM), tri-(2-ethylhexyl) trimellitate
(TOTM), tri-(n-octyl,n-decyl) trimellitate, tri-(heptyl,nonyl)
trimellitate, tri-n-octyl trimellitate; as well as benzoates
including, but not limited to, 2-ethylhexyl-4-hydroxy benzoate,
n-octyl benzoate, methyl benzoate, and ethyl benzoate.
[0142] Also suitable are alkyl diacid esters commonly based on
C.sub.4-C.sub.12 alkyl dicarboxylic acids such as adipic, sebacic,
azelaic, and maleic acids such as: bis(2-ethylhexyl)adipate (DEHA),
dimethyl adipate (DMAD), monomethyl adipate (MMAD), dioctyl adipate
(DOA), dibutyl sebacate (DBS), dibutyl maleate (DBM), diisobutyl
maleate (DIBM), dioctyl sebacate (DOS). Also, esters based on
glycols, polyglycols, and polyhydric alcohols, such as
poly(ethylene glycol) mono- and di-esters, cyclohexanedimethanol
esters, sorbitol derivatives; and triethylene glycol dihexanoate,
diethylene glycol di-2-ethylhexanoate, tetraethylene glycol
diheptanoate, and ethylene glycol dioleate, may be used.
[0143] Fatty acids, fatty acid salts, fatty acid amides, and fatty
acid esters also may be used in the compositions of this invention.
Compounds such as stearic, oleic, ricinoleic, behenic, myristic,
linoleic, palmitic, and lauric acid esters, salts, and mono- and
bis-amides can be used. Ethyl oleate, butyl stearate, methyl
acetylricinoleate, zinc oleate, ethylene bis-oleamide, and stearyl
erucamide are suitable. Suitable fatty acid salts include, for
example, metal stearates, erucates, laurates, oleates, palmitates,
pelargonates, and the like. For example, fatty acid salts such as
zinc stearate, calcium stearate, magnesium stearate, barium
stearate, and the like can be used. Fatty alcohols and acetylated
fatty alcohols are also suitable, as are carbonate esters such as
propylene carbonate and ethylene carbonate.
[0144] Glycerol-based esters such as soy-bean, tung, or linseed
oils or their epoxidized derivatives can also be used as
plasticizers in the present invention, as can polymeric polyester
plasticizers formed from the esterification reaction of diacids and
diglycols as well as from the ring-opening polymerization reaction
of caprolactones with diacids or diglycols. Citrate esters and
acetylated citrate esters are also suitable.
[0145] Dicarboxylic acid molecules containing both a carboxylic
acid ester and a carboxylic acid salt can perform suitably as
plasticizers. The magnesium salt of mono-methyl adipate and the
zinc salt of mono-octyl glutarate are two such examples for this
invention. Tri- and tetra-carboxylic acid esters and salts can also
be used.
[0146] Also envisioned as suitable plasticizers are organophosphate
and organosulfur compounds such as tricresyl phosphate (TCP),
tributyl phosphate (TBP), alkyl sulfonic acid phenyl esters (ASE);
and sulfonamides such as N-ethyl toluene sulfonamide,
N-(2-hydroxypropyl) benzene sulfonamide, N-(n-butyl) benzene
sulfonamide. Furthermore, thioester and thioether variants of the
plasticizer compounds mentioned above are suitable.
[0147] Non-ester plasticizers such as alcohols, polyhydric
alcohols, glycols, polyglycols, and polyethers are suitable
materials for plasticization. Materials such as polytetramethylene
ether glycol, poly(ethylene glycol), and poly(propylene glycol),
oleyl alchohol, and cetyl alcohol can be used. Hydrocarbon
compounds, both saturated and unsaturated, linear or cyclic can be
used such as mineral oils, microcrystalline waxes, or low-molecular
weight polybutadiene. Halogenated hydrocarbon compounds can also be
used.
[0148] Other examples of polyamide plasticizers that may be used in
the composition of this invention include butylbenzenesulphonamide
(BBSA), ethylhexyl para-hydroxybenzoate (EHPB) and decylhexyl
para-hydroxybenzoate (DHPB), as disclosed in U.S. Pat. No.
6,376,037, the disclosure of which is hereby incorporated by
reference.
[0149] Esters and alkylamides such as phthalic acid esters
including dimethyl phthalate, diethyl phthalate, dibutyl phthalate,
diheptyl phthalate, di-2-ethylhexyl phthalate, di-n-octyl
phthalate, diisodecyl phthalate, ditridecyl phthalate, dicyclohexyl
phthalate, butylbenzyl phthalate, diisononyl phthalate,
ethylphthalylethyl glycolate, butylphthalylbutyl glycolate,
diundecyl phthalate, di-2-ethylhexyl tetrahydrophthalate as
disclosed in Isobe et al., U.S. Pat. No. 6,538,099, the disclosure
of which is hereby incorporated by reference, also may be used.
[0150] U.S. Pat. No. 7,045,185, the disclosure of which is hereby
incorporated by reference, discloses sulphonamides such as
N-butylbenzenesulphonamide, ethyltoluene-suiphonamide,
N-cyclohexyltoluenesulphonamide, 2-ethylhexyl-para-hydroxybenzoate,
2-decylhexyl-para-hydroxybenzoate,
oligoethyleneoxytetrahydrofurfuryl alcohol, or oligoethyleneoxy
malonate; esters of hydroxybenzoic acid; esters or ethers of
tetrahydrofurfuryl alcohol, and esters of citric acid or
hydroxymalonic acid; and these plasticizers also may be used.
[0151] Sulfonamides are particularly preferred plasticizers fur use
in the present invention, and these materials are described in U.S.
Pat. No. 7,297,737, the disclosure of which is hereby incorporated
by reference. Examples of such sulfonamides include N-alkyl
benzenesulfonamides and toluenesufonamides, particularly
N-butylbenzenesulfonamide, N-(2-hydroxypropyl)benzenesulfonamide,
N-ethyl-o-toluenesulfonamide, N-ethyl-p-toluenesulfonamide,
o-toluenesulfonamide, p-toluenesulfonamide. Such sulfonamide
plasticizers also are described in U.S. Patent Application
Publication No. 2010/0183837, the disclosure of which is hereby
incorporated by reference. The polyamide compositions containing
plasticizer, as described in the above patent references, also may
be used in this invention.
[0152] A preferred golf ball includes a core and a three-layer
cover disposed adjacent the core. The three-layer cover includes an
inner cover, an intermediate cover, and an outer cover. The inner
cover includes a non-ionomeric E/Y copolymer where E is an olefin
and Y is a carboxylic acid. The inner cover has a hardness of about
45 to 68 Shore D. The outer cover includes a castable thermoset
polyurethane and has a hardness of about 40 to 62 Shore D. The
intermediate cover layer, disposed between the inner and outer
cover layers, is formed from a polyester composition including
about 40 wt % to about 99 wt % of a polyester thermoplastic
elastomer and about 1 wt % to about 60 wt % of a plasticizer.
[0153] Preferably, the polyester thermoplastic elastomer is a
polyester-polyether block copolymer. In one embodiment, the
polyester-polyether block copolymer has a flex modulus of about
50,000 psi or less. The polyester composition may further include
an acid copolymer of ethylene and an .alpha.,.beta.-unsaturated
carboxylic acid, and a cation source present in an amount
sufficient to neutralize from about 0 to about 100% of all acid
groups present in the composition. Optionally, the composition
includes a softening monomer, such as alkyl acrylate and alkyl
methacrylate.
[0154] Preferably, the acid groups of the acid copolymer of
ethylene are neutralized by about 80% or greater, more preferably
about 90% or greater, and most preferably about 100%. The
plasticizer is preferably present in an amount of about 10 wt % to
about 30 wt %. In one embodiment, the plasticizer is a fatty acid
ester. Alternatively, the plasticizer includes an alkyl oleate.
Preferably, the alkyl oleate is methyl oleate, ethyl oleate, propyl
oleate, butyl oleate, or octyl oleate.
[0155] Preferred golf ball constructions of the present invention
also include a golf ball having a three-layer cover including an
inner cover layer, an intermediate cover layer, and an outer cover
layer, where the intermediate layer comprises a transparent
polyamide or a blend thereof. The golf ball may, alternatively,
have a 2-layer cover including an inner cover layer and an outer
cover layer, where the inner cover layer is formed from a
transparent polyamide or blend thereof. The transparent polyamides
of the present invention preferably have a Tg of about 75.degree.
C. to about 160.degree. C., more preferably about 80.degree. C. to
95.degree. C., and a Charpy notched impact resistance of about 15
kJ/m.sup.2 at 23.degree. C. or greater, more preferably about 50
kJ/m.sup.2 at 23.degree. C. or greater. Preferred transparent
polyamides or blends thereof for use in intermediate layers of the
invention have a ratio of Charpy notched impact resistance at
23.degree. C. to Charpy notched impact resistance at -30.degree. C.
of at least about 2.0, more preferably at least about 4.0.
[0156] Preferred transparent polyamides include those having an
amorphous, quasi-amorphous, semi-crystalline, or micro-crystalline
structure. One preferred transparent polyamide is a polyether-amide
block copolymer. An alternative preferred embodiment includes an
intermediate layer formed from a blend of transparent and
non-transparent polyamides.
[0157] In an alternative embodiment, the golf ball has a 3-layer
cover including an inner cover layer, an intermediate cover layer,
and an outer cover layer, where the intermediate layer comprises a
plasticized polyamide. The plasticized polyamide material, or
blends thereof, may also be used in a 2-piece golf ball
construction to form the inner cover layer. The plasticized
polyamide composition typically include about 40% by weight to
about 99% by weight polyamide and about 1% by weight to about 60%
by weight of a plasticizer. Preferably the polyamide is
polyether-amide block polymers, polyamide 6; polyamide 6,6;
polyamide 6,10; polyamide 6,12; polyamide 11; polyamide 12;
polyamide 6,9; and polyamide 4,6, and copolymers and blends thereof
and the plasticizer is the plasticizer is selected from the group
consisting of N-butylbenzenesulfonamide; N-ethylbenzenesulfonamide;
N-propylbenzenesulfonamide; N-butyl-N-dodecylbenzenesulfonamide;
N,N-dimethylbenzenesulfonamide; p-methylbenzenesulfonamide;
o,p-toluene sulfonamide; p-toluene sulfonamide;
2-ethylhexyl-4-hydroxybenzoate; hexadecyl-4-hydroxybenzoate;
1-butyl-4-hydroxybenzoate; dioctyl phthalate; diisodecyl phthalate;
di-(2-ethylhexyl) adipate; and tri-(2-ethylhexyl) phosphate,
propylene carbonate, an alkyl or aryl fatty acid ester. In a
preferred embodiment, the plasticizer is ethyl oleate or propylene
carbonate. The plasticized polyamides or blends thereof may be
transparent and non-transparent.
[0158] In any of these constructions, it is preferred that the
transparent polyamide material have a light transmission of at
least about 80%, more preferably about 85%, and most preferably
about 90%. In an alternative construction, the intermediate layer
in a 3-layer cover or the inner cover layer in a 2-layer cover may
be formed from a transparent polyamide (or blend of transparent
polyamides) and an acid-anhydride-modified polyolefin, such as
FUSABOND.RTM., where the acid-anhydride-modified polyolefin is
preferably present in an amount of about 1% by wt to about 60% by
wt. The acid anhydride-modified polyolefin is preferably an
ethylene-based copolymer--the acid anhydride used to modify the
ethylene-based copolymer can be, for example, maleic, fumaric,
nadic, itaconic, and clorendic acid anhydrides, and substituted
derivatives thereof.
[0159] While the inventive golf ball may be formed from a variety
of differing cover materials, preferred outer cover layer 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.
[0160] Suitable polyurethane compositions comprise a reaction
product of at least one polyisocyanate and at least one curing
agent. The curing agent can include, for example, one or more
polyamines, one or more polyols, or a combination thereof. The
polyisocyanate can be combined with one or more polyols to form a
prepolymer, which is then combined with the at least one curing
agent. Thus, the polyols described herein are suitable for use in
one or both components of the polyurethane material, i.e., as part
of a prepolymer and in the curing agent. Suitable polyurethanes are
described in U.S. Pat. No. 7,331,878, which is incorporated by
reference in its entirety.
[0161] 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 (H12MDI); 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.
[0162] 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.
[0163] 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.
[0164] 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.
[0165] 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.
[0166] 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.
[0167] 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.
[0168] 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.
[0169] 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.
[0170] 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. 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.
[0171] Saturated diisocyanates which can be used include, without
limitation, ethylene diisocyanate; propylene-1,2-diisocyanate;
tetramethylene-1,4-diisocyanate; 1,6-hexamethylene-diisocyanate;
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.
[0172] 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.
[0173] 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.
[0174] 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.
[0175] 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.
[0176] 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.
[0177] 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.
[0178] 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.).
[0179] 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, and more preferably is
between about 1500 to about 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.
[0180] 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.
[0181] 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.
[0182] 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.
[0183] Examples of diisocyanates that can be used with the present
invention include, but are not limited to, substituted and isomeric
mixtures including 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; para-phenylene diisocyanate;
meta-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; 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; meta-tetramethylxylene diisocyanate;
para-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.
[0184] Examples of saturated diisocyanates that can be used with
the present invention include, but are not limited to, ethylene
diisocyanate; propylene-1,2-diisocyanate; tetramethylene
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; 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; and mixtures thereof. 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;
meta-tetramethylxylene diisocyanate; para-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.
[0185] 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.
[0186] 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.
[0187] 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.
[0188] 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.
[0189] Suitable amine-terminated curing agents include, but are not
limited to, ethylene diamine; hexamethylene diamine;
1-methyl-2,6-cyclohexyl diamine; tetrahydroxypropylene ethylene
diamine; 2,2,4- and 2,4,4-trimethyl-1,6-hexanediamine;
4,4'-bis-(sec-butylamino)-dicyclohexylmethane;
1,4-bis-(sec-butylamino)-cyclohexane;
1,2-bis-(sec-butylamino)-cyclohexane; derivatives of
4,4'-bis-(sec-butylamino)-dicyclohexylmethane;
4,4'-dicyclohexylmethane diamine;
1,4-cyclohexane-bis-(methylamine);
1,3-cyclohexane-bis-(methylamine); diethylene glycol
di-(aminopropyl) ether; 2-methylpentamethylene-diamine;
diaminocyclohexane; diethylene triamine; triethylene tetramine;
tetraethylene pentamine; propylene diamine; 1,3-diaminopropane;
dimethylamino propylamine; diethylamino propylamine; dipropylene
triamine; imido-bis-propylamine; monoethanolamine, diethanolamine;
triethanolamine; monoisopropanolamine, diisopropanolamine;
isophoronediamine; 4,4'-methylenebis-(2-chloroaniline); 3,5;
dimethylthio-2,4-toluenediamine;
3,5-dimethylthio-2,6-toluenediamine;
3,5-diethylthio-2,4-toluenediamine; 3,5;
diethylthio-2,6-toluenediamine;
4,4'-bis-(sec-butylamino)-diphenylmethane and derivatives thereof;
1,4-bis-(sec-butylamino)-benzene; 1,2-bis-(sec-butylamino)-benzene;
N,N'-dialkylamino-diphenylmethane; N,N,N',N'-tetrakis
(2-hydroxypropyl) ethylene diamine;
trimethyleneglycol-di-p-aminobenzoate;
polytetramethyleneoxide-di-p-aminobenzoate;
4,4'-methylenebis-(3-chloro-2,6-diethyleneaniline);
4,4'-methylenebis-(2,6-diethylaniline); meta-phenylenediamine;
paraphenylenediamine; and mixtures thereof. In one embodiment, the
amine-terminated curing agent is
4,4'-bis-(sec-butylamino)-dicyclohexylmethane.
[0190] Suitable saturated amine-terminated curing agents include,
but are not limited to, ethylene diamine; hexamethylene diamine;
1-methyl-2,6-cyclohexyl diamine; tetrahydroxypropylene ethylene
diamine; 2,2,4- and 2,4,4-trimethyl-1,6-hexanediamine;
4,4'-bis-(sec-butylamino)-dicyclohexylmethane;
1,4-bis-(sec-butylamino)-cyclohexane;
1,2-bis-(sec-butylamino)-cyclohexane; derivatives of
4,4'-bis-(sec-butylamino)-dicyclohexylmethane;
4,4'-dicyclohexylmethane diamine;
4,4'-methylenebis-(2,6-diethylaminocyclohexane;
1,4-cyclohexane-bis-(methylamine);
1,3-cyclohexane-bis-(methylamine); diethylene glycol
di-(aminopropyl) ether; 2-methylpentamethylene-diamine;
diaminocyclohexane; diethylene triamine; triethylene tetramine;
tetraethylene pentamine; propylene diamine; 1,3-diaminopropane;
dimethylamino propylamine; diethylamino propylamine;
imido-bis-propylamine; monoethanolamine, diethanolamine;
triethanolamine; monoisopropanolamine, diisopropanolamine;
isophoronediamine; triisopropanolamine; and mixtures thereof. In
addition, any of the polyether amines listed above may be used as
curing agents to react with the polyurea prepolymers.
[0191] Any of the above inner, intermediate, or outer cover 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
%.
[0192] The layer 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.
[0193] An optional filler component may be chosen to impart
additional density to blends of the previously described
components. 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.
[0194] 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.
[0195] 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.
[0196] 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.
[0197] 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.
[0198] 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.
[0199] 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.
[0200] 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.
[0201] 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.
[0202] 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.
[0203] 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).
[0204] 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.
[0205] The intermediate cover layer has a hardness of about 55 to
90 Shore D, preferably about 57 to 80 Shore D, and more preferably
about 61 to 69 Shore D. Alternatively, the intermediate cover layer
has a hardness of about 65 to 110 Shore C, preferably about 72 to
100 Shore C, and more preferably about 74 to 92 Shore C.
[0206] 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.
[0207] 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 a non-ionomeric E/Y copolymer comprising an
ethylene/acrylic acid copolymer 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 thermoplastic polycarbonate-polyurethane
copolymer 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 polyurethane 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.
[0208] 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 stiff TPU 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.
[0209] 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.
[0210] 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.
[0211] 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.
[0212] 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.
[0213] 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.
[0214] 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.
[0215] 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.
[0216] 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.
[0217] 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.
* * * * *