U.S. patent application number 12/426311 was filed with the patent office on 2009-08-13 for golf balls containing highly-neutralized acid polymers and ionic plasticizers.
Invention is credited to Michael J. Sullivan.
Application Number | 20090203469 12/426311 |
Document ID | / |
Family ID | 40939383 |
Filed Date | 2009-08-13 |
United States Patent
Application |
20090203469 |
Kind Code |
A1 |
Sullivan; Michael J. |
August 13, 2009 |
GOLF BALLS CONTAINING HIGHLY-NEUTRALIZED ACID POLYMERS AND IONIC
PLASTICIZERS
Abstract
A golf ball comprising a core and a cover layer, wherein at
least one of the core and the cover layer includes a polymer
composition of a highly-neutralized acid polymer and an ionic
plasticizer is disclosed and described. The highly-neutralized acid
polymer can comprise at least 50 wt % of the polymer composition
and have 70% to 100% of the acid groups neutralized. In addition,
the ionic plasticizer can be alcohol esters, montanic acids,
montanic acid esters, alkylene bis-amines, zwitterionic compounds,
salts thereof, or combinations thereof.
Inventors: |
Sullivan; Michael J.;
(Barrington, RI) |
Correspondence
Address: |
ACUSHNET COMPANY
333 BRIDGE STREET, P. O. BOX 965
FAIRHAVEN
MA
02719
US
|
Family ID: |
40939383 |
Appl. No.: |
12/426311 |
Filed: |
April 20, 2009 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12110418 |
Apr 28, 2008 |
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12426311 |
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11216726 |
Aug 31, 2005 |
7365128 |
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12110418 |
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Current U.S.
Class: |
473/374 ;
473/371 |
Current CPC
Class: |
A63B 37/0045 20130101;
C08K 5/09 20130101; A63B 37/0065 20130101; A63B 37/0043 20130101;
C08K 5/0016 20130101; A63B 37/0061 20130101; A63B 37/0049 20130101;
C08L 33/02 20130101; A63B 37/0038 20130101; C08L 33/02 20130101;
C08L 2666/02 20130101 |
Class at
Publication: |
473/374 ;
473/371 |
International
Class: |
A63B 37/00 20060101
A63B037/00 |
Claims
1. A golf ball comprising a core and a cover layer, wherein at
least one of the core and the cover layer includes a polymer
composition, comprising: a highly-neutralized acid polymer having
acid groups comprising at least 50 wt % of the polymer composition
wherein 70% to 100% of the acid groups are neutralized; and an
ionic plasticizer being selected from the group consisting of
alcohol esters, montanic acids, montanic acid esters, alkylene
bis-amines, zwitterionic compounds, salts thereof, and combinations
thereof.
2. The golf ball of claim 1, wherein the core includes a center and
an outer core layer, or the cover layer is a double layer cover
having an inner cover layer and an outer cover layer.
3. The golf ball of claim 2, and wherein the polymer composition is
present in the outer core layer or the inner cover layer.
4. The golf ball of claim 1, wherein the polymer composition is
present in the core.
5. The golf ball of claim 1, wherein the polymer composition is
present in the cover layer.
6. The golf ball of claim 1, wherein the highly-neutralized acid
polymer is a copolymer of a C.sub.3 to C.sub.8
.alpha.,.beta.-ethylenically unsaturated carboxylic acid and a
C.sub.2 to C.sub.6 .alpha.-olefin.
7. The golf ball of claim 1, wherein the highly-neutralized acid
polymer further includes a softening monomer admixed or
copolymerized therewith.
8. The golf ball of claim 1, wherein the acid groups are at least
95% neutralized.
9. The golf ball of claim 1, wherein the ionic plasticizer is a
polyalcohol ester.
10. The golf ball of claim 9, wherein the polyalcohol ester is
selected from the group consisting of glycerol monostearate,
pentaerythritol distearate, glycerine monooleate, glycerine
dioleate, pentaerythritol tetrastearate, pentaerythritol
tetraisostearate, pentaerythritol tetraoleate, neo-pentyl glycol
dioleate, and combinations thereof.
11. The golf ball of claim 1, wherein the ionic plasticizer is a
montanic acid, montanic acid ester, or salt thereof.
12. The golf ball of claim 11, wherein the montanic acid ester or
salt thereof is a reaction product of montanic acid and an alcohol
selected from the group consisting of C.sub.1-C.sub.4 alkanols,
C.sub.1-C.sub.4 alkylene glycols, glycerol, and combinations
thereof.
13. The golf ball of claim 1, wherein the ionic plasticizer is an
alkylene bis-amine.
14. The golf ball of claim 13, wherein the alkylene bis-amine is a
fatty acid amine.
15. The golf ball of claim 14, wherein the fatty acid amine is
bis-stearoylethylenediamine, ethylene bisstearamide, oleamide, or
erucamide.
16. The golf ball of claim 1, wherein the ionic plasticizer is a
zwitterionic compound.
17. The golf ball of claim 16, wherein the zwitterionic compound is
N,N-dimethyl-N-stearyl-N-(3-sulfopropyl)-ammonium betaine.
18. The golf ball of claim 1, wherein the golf ball has a
coefficient of restitution of at least 0.810 and an Atti
compression from 90 to 100.
19. The golf ball of claim 1, wherein the polymer composition is
substantially devoid of fatty acids and polyhydric alcohols.
20. A golf ball, comprising: a solid core; a cover layer comprising
a polyurethane or polyurea; and an intermediate layer disposed
between the solid core and the cover layer, wherein the
intermediate layer includes a polymer composition, comprising: a
highly-neutralized acid polymer having acid groups comprising at
least 50 wt % of the polymer composition and wherein at least 98%
of the acid groups are neutralized; and an ionic plasticizer
comprising a montanic acid, montanic acid ester, or salt thereof.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation-in-part of U.S.
application Ser. No. 12/110,418, filed on Apr. 28, 2008, which is a
continuation of U.S. Pat. No. 7,365,128, each of which are
incorporated herein by reference.
FIELD OF THE INVENTION
[0002] This invention relates to golf balls containing
highly-neutralized acid polymers. More specifically, the present
invention relates to golf balls containing specific combinations of
highly-neutralized acid polymers and ionic plasticizers.
BACKGROUND OF THE INVENTION
[0003] Solid golf balls typically include one-piece, two-piece
(i.e., solid core and a cover), and multi-layer (i.e., solid core
of one or more layers and/or a cover of one or more layers) golf
balls. Golf ball core and cover layers are typically constructed
with polymer compositions including, for example, polybutadiene
rubber, polyurethanes, polyamides, ionomers, and blends thereof.
Ionomers, particularly ethylene-based ionomers, have become a
common choice of polymers for golf ball layers because of their
toughness, durability, and wide range of hardness values.
[0004] Ionomers can be stiffened by increasing the amount of
neutralization. Neutralization to 70% and higher, including 100%,
has been disclosed. However, in the absence of flow additives, at
neutralization levels above about 60%, the melt flow of the ionomer
is decreased to an extent such that processability decreases or
disappears altogether. For trivalent cations, the percent
neutralization at which the polymer becomes unprocessable, in the
absence of flow additives, can be significantly lower.
[0005] Blending ionomers with fatty acids is a known method for
improving the processability of highly-neutralized polymers. The
use of polyhydric alcohols in golf ball compositions is also known
in certain golf ball resins. Although improvements in
processability and golf ball properties have been achieved, the use
of fatty acids or their salts at high levels can lead to
discoloration (yellowing) and to surface blooming with subsequent
coating adhesion problems.
SUMMARY OF THE INVENTION
[0006] The present invention provides a golf ball comprising a core
and a cover layer, wherein at least one of the core and the cover
layer includes a polymer composition of a highly-neutralized acid
polymer and an ionic plasticizer. The highly-neutralized acid
polymer having acid groups can comprise at least 50 wt % of the
polymer composition and have 70% to 100% of the acid groups
neutralized. In addition, the ionic plasticizer can be selected
from the group consisting of alcohol esters, montanic acids,
montanic acid esters, alkylene bis-amines, zwitterionic compounds,
salts thereof, and combinations thereof.
[0007] The present invention is also directed to a golf ball
including a core and a cover layer. At least one of the core or the
cover layer is formed from a polymer composition including 1) a
highly-neutralized acid polymer having acid groups comprising at
least 50 wt % of the polymer composition. Preferably, 70% to 100%
of the acid groups are neutralized; and 2) an ionic plasticizer,
such as alcohol esters, montanic acids, montanic acid esters,
alkylene bis-amines, zwitterionic compounds, salts thereof, or a
blend thereof.
[0008] The core may be a single solitary layer or be a `dual core`,
such as one including a center and an outer core layer. In a
preferred embodiment, the cover layer is a `double cover` having an
inner cover layer and an outer cover layer.
[0009] In one embodiment, the polymer composition is present in the
outer core layer or the inner cover layer. In another embodiment,
the polymer composition is present in the core. In an alternative
embodiment, the polymer composition is present in the cover
layer.
[0010] The highly-neutralized acid polymer is typically a copolymer
of a C.sub.3 to C.sub.8 .alpha.,.beta.-ethylenically unsaturated
carboxylic acid and a C.sub.2 to C.sub.6 .alpha.-olefin. The
highly-neutralized acid polymer may further include a softening
monomer admixed or copolymerized therewith. Preferably, the acid
groups are at least 95% neutralized.
[0011] The ionic plasticizer is typically a polyalcohol ester,
preferably one such as glycerol monostearate, pentaerythritol
distearate, glycerine monooleate, glycerine dioleate,
pentaerythritol tetrastearate, pentaerythritol tetraisostearate,
pentaerythritol tetraoleate, neo-pentyl glycol dioleate, or a blend
thereof. The ionic plasticizer may also be montanic acid, montanic
acid ester, or salt thereof. The montanic acid ester or salt
thereof is a reaction product of montanic acid and an alcohol, such
as C.sub.1-C.sub.4 alkanols, C.sub.1-C.sub.4 alkylene glycols,
glycerol, and blends thereof. Preferably, the ionic plasticizer is
an alkylene bis-amine. Preferably, the alkylene bis-amine is a
fatty acid amine, such as bis-stearoylethylenediamine, ethylene
bisstearamide, oleamide, or erucamide. The ionic plasticizer may
also be a zwitterionic compound, such as
N,N-dimethyl-N-stearyl-N-(3-sulfopropyl)-ammonium betaine.
[0012] The golf ball ideally has a coefficient of restitution
("COR") of at least 0.810 and an Atti compression from 90 to 105,
preferably 92 to 100. In one alternative embodiment, the polymer
composition is substantially devoid of fatty acids and polyhydric
alcohols.
[0013] The present invention is further directed to a golf ball
including a solid core, a cover layer formed from a polyurethane or
polyurea, and an intermediate layer disposed between the solid core
and the cover layer. The intermediate layer is preferably formed
from a polymer composition including 1) a highly-neutralized acid
polymer having acid groups comprising at least 50 wt % of the
polymer composition where at least 98% of the acid groups are
neutralized; and 2) an ionic plasticizer, such as montanic acid,
montanic acid ester, or salt thereof.
[0014] There has thus been outlined, rather broadly, certain
features of the invention so that the detailed description thereof
that follows may be better understood, and so that the present
contribution to the art may be better appreciated. Other features
of the present invention will become clearer from the following
detailed description of the invention, taken with the accompanying
claims, or may be learned by the practice of the invention.
DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS
[0015] The following detailed description of the embodiments of the
present invention is not intended to limit the scope of the
invention, as claimed, but is presented for purposes of
illustration only, and not to necessarily limit features and
characteristics of the present invention. Rather, the description
is intended to set forth the best mode of operation of the
invention, and to sufficiently enable one skilled in the art to
practice the invention. Accordingly, the scope of the present
invention is to be defined by the appended claims.
[0016] In describing and claiming the present invention, the
following terminology will be used.
[0017] The singular forms "a," "an," and "the" include plural
referents unless the context clearly dictates otherwise. Thus, for
example, reference to "a layer" includes reference to one or more
of such layers.
[0018] As used herein with respect to an identified property or
circumstance, "substantially" refers to a degree of deviation that
is sufficiently small so as to not measurably detract from the
identified property or circumstance. The exact degree of deviation
allowable may in some cases depend on the specific context. For
example, "substantially free," as used herein, means that the
composition does not contain the cited material in any significant
amount, e.g., substantially free of fatty acids or their salts
thereof may include either absolutely no fatty acids or salts, or
an amount of less than 0.5 wt % based on the total polymeric weight
of the composition.
[0019] As used herein, "adjacent" refers to the proximity of two
structures or elements. Particularly, elements that are identified
as being "adjacent" may be either abutting or connected. Such
elements may also be near or close to each other without
necessarily contacting one another.
[0020] As used herein, "highly-neutralized acid polymer" refers to
an acid polymer or copolymer after at least 70%, at least 90%, at
least 95%, at least 98%, or 100% of the acid groups thereof are
neutralized by a cation source. Neutralization can be effected
prior to, during, or after combining the acid polymer(s) with the
polyhydric alcohol(s). Preferably, the polyhydric alcohol is
combined with an unneutralized or partially neutralized (i.e., less
than 70% neutralized) acid polymer, and a cation source is
subsequently added to further neutralize the acid polymer to 70%
neutralization or higher.
[0021] The term "copolymer," as used herein, includes polymers
having two types of monomers, those having three types of monomers,
and those having more than three types of monomers polymerized
together.
[0022] As used herein, "(meth) acrylic acid" means methacrylic acid
and/or acrylic acid. Likewise, "(meth)acrylate" means methacrylate
and/or acrylate.
[0023] As used herein, a plurality of items, structural elements,
compositional elements, and/or materials may be presented in a
common list for convenience. However, these lists should be
construed as though each member of the list is individually
identified as a separate and unique member. Thus, no individual
member of such list should be construed as a de facto equivalent of
any other member of the same list solely based on their
presentation in a common group without indications to the
contrary.
[0024] Concentrations, amounts, and other numerical data may be
presented herein in a range format. It is to be understood that
such range format is used merely for convenience and brevity and
should be interpreted flexibly to include not only the numerical
values explicitly recited as the limits of the range, but also to
include all the individual numerical values or sub-ranges
encompassed within that range as if each numerical value and
sub-range is explicitly recited. For example, a numerical range of
about 1 to about 4.5 should be interpreted to include not only the
explicitly recited limits of 1 to about 4.5, but also to include
individual numerals such as 2, 3, 4, and sub-ranges such as 1 to 3,
2 to 4, etc. The same principle applies to ranges reciting only one
numerical value, such as "less than about 4.5," which should be
interpreted to include all of the above-recited values and ranges.
Further, such an interpretation should apply regardless of the
breadth of the range or the characteristic being described.
[0025] 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.
[0026] All patents, publications, test procedures, and other
references cited herein, including priority documents, are fully
incorporated by reference to the extent such disclosure is not
inconsistent with this invention and for all jurisdictions in which
such incorporation is permitted.
[0027] In the present disclosure, any steps recited in any method
or process claims may be executed in any order and are not limited
to the order presented.
[0028] With this in mind, golf balls of the present invention can
include one-piece, two-piece, multi-layer, and wound golf balls
having a variety of core structures, intermediate layers, covers,
and coatings. Golf ball cores may comprise a single, unitary layer,
comprising the entire core from the center of the core to its outer
periphery. Alternatively, the cores may consist of a center
surrounded by at least one outer core layer. The center, innermost
portion of such multi-layer cores is most often solid, but may be
hollow or liquid-, gel-, or gas-filled. The outer core layer may be
solid, or it may be a wound layer formed of a tensioned elastomeric
material. Golf ball covers may also include one or more layers,
such as a double cover having an inner and outer cover layer.
Optionally, additional intermediate layers may be disposed between
the core and cover. The HNP-containing composition is most often
included in an intermediate layer, such as an outer core layer or
inner cover layer, of a multi-layer golf ball. However, the
HNP-containing composition can be included in any one of the layers
or combinations of layers.
[0029] In the golf balls of the present invention, at least one
layer comprises an HNP-containing composition, including an ionic
plasticizer as described herein. The acid polymers of the present
invention are generally homopolymers or copolymers of
.alpha.,.beta.-ethylenically unsaturated mono- or dicarboxylic
acids, including combinations thereof. Non-limiting examples of
.alpha.,.beta.-ethylenically unsaturated mono- or dicarboxylic
acids are (meth) acrylic acid, ethacrylic acid, maleic acid,
crotonic acid, fumaric acid, itaconic acid. (Meth) acrylic acid is
currently most common.
[0030] In one aspect of the present invention, acid polymers can be
copolymers of a C.sub.3 to C.sub.8 .alpha.,.beta.-ethylenically
unsaturated mono- or dicarboxylic acid and ethylene or a C.sub.3 to
C.sub.6 .alpha.-olefin, optionally including a softening monomer.
Particularly suitable acid polymers are copolymers of ethylene and
(meth) acrylic acid, such as those including a softening monomer.
When a softening monomer is included, such copolymers are referred
to herein as an E/X/Y-type copolymer, wherein E is ethylene, X is a
C.sub.3 to C.sub.8 .alpha.,.beta.-ethylenically unsaturated mono-
or dicarboxylic acid, and Y is a softening monomer. The softening
monomer is typically an alkyl(meth)acrylate, wherein the alkyl
groups have from 1 to 8 carbon atoms. Specific non-limiting
examples of E/X/Y-type copolymers are those where X is (meth)
acrylic acid and/or Y is selected from (meth)acrylate,
n-butyl(meth)acrylate, isobutyl(meth)acrylate,
methyl(meth)acrylate, and ethyl(meth)acrylate. Particularly
suitable E/X/Y-type copolymers are ethylene/(meth) acrylic
acid/n-butyl acrylate, ethylene/(meth) acrylic acid/methyl
acrylate, and ethylene/(meth) acrylic acid/ethyl acrylate. In
another aspect, the acid polymer can be ethylene-acrylic or (meth)
acrylic copolymers or terpolymers (e.g. an alkyl ester such as
butyl acrylate).
[0031] The amount of ethylene or C.sub.3 to C.sub.6 .alpha.-olefin
in the acid copolymer is typically at least 15 wt %, in some cases
at least 25 wt %, in other cases at least 40 wt %, and in others at
least 60 wt %, based on the total weight of the copolymer. The
amount of C.sub.3 to C.sub.8 .alpha.,.beta.-ethylenically
unsaturated mono- or dicarboxylic acid in the acid copolymer is
typically from 1 wt % to 35 wt %, such as from 5 wt % to 30 wt %,
from 5 wt % to 25 wt %, or from 10 wt % to 20 wt %, based on the
total weight of the copolymer. If present, the amount of optional
softening comonomer in the acid copolymer can be from 0.01 wt % to
50 wt %, from 5 wt % to 40 wt %, from 10 wt % to 35 wt %, or from
20 wt % to 30 wt %, based on the total weight of the copolymer.
[0032] Further examples of suitable acid polymers include
Surlyn.RTM. ionomers, commercially-available from DuPont;
AClyn.RTM. ionomers, commercially-available from Honeywell
International Inc.; Iotek.RTM. ionomers, commercially-available
from ExxonMobil Chemical Company; and the acid copolymers described
in U.S. Patent Application Publication No. 2003/0130434, the entire
disclosure of which is hereby incorporated herein by reference.
[0033] The acid polymers of the present invention can be direct
copolymers where the polymer is polymerized by adding all monomers
simultaneously, as described in, for example, U.S. Pat. No.
4,351,931, the entire disclosure of which is hereby incorporated
herein by reference. Ionomers can also be made from direct
copolymers, as described in, for example, U.S. Pat. No. 3,264,272
to Rees, the entire disclosure of which is hereby incorporated
herein by reference. Alternatively, the acid polymers of the
present invention can be graft copolymers, wherein a monomer is
grafted onto an existing polymer, as described in, for example,
U.S. Patent Application Publication No. 2002/0013413, the entire
disclosure of which is hereby incorporated herein by reference.
Other polymer types can also be prepared, as are known in the art,
e.g., block copolymers, random copolymers, etc.
[0034] Suitable cation sources include metal cations and salts
thereof, organic amine compounds, ammonium, and combinations
thereof. Most often, cation sources are metal cations and salts
thereof, wherein the metal is lithium, sodium, potassium,
magnesium, calcium, barium, lead, tin, zinc, aluminum, manganese,
nickel, chromium, copper, or a combination thereof. Other cation
sources can also be suitable. The amount of cation used in the
HNP-containing composition is readily determined based on the
desired level of neutralization.
[0035] The highly-neutralized acid polymer can comprise at least 50
wt % of the polymer composition such as about 60 wt % to about 95
wt %. Most often, the highly-neutralized acid polymer can comprise
about 65 wt % to about 90 wt % of the polymer composition.
[0036] As previously described, the HNP-containing compositions of
the present invention include one or more highly-neutralized acid
polymer(s) and one or more polyhydric alcohol(s). It has been found
that by adding a sufficient amount of a polyhydric alcohol to
compositions containing an acid polymer, the acid groups of the
acid polymer can be neutralized at high levels, including up to
100%, without requiring a fatty acid to maintain
processability.
[0037] However, the HNP-containing compositions may contain fatty
acids and salts thereof, but are processible without them. If used,
organic acids can be blended or melt-blended with other ionomers or
polymers as an unmodified or modified organic acid or salt thereof.
Typically, the organic acids or salts thereof can be aliphatic,
monofunctional organic acids having from 6 to 36 carbon atoms per
molecule. These organic acids can be partially neutralized or fully
neutralized. For example, greater than 80% or greater than 90%, and
in some cases 100% of all the acid components in the blend can be
neutralized. The organic acids can typically also be non-volatile
and non-migratory. Non-limiting examples of suitable fatty acid as
the organic acid can include caproic acid, caprylic acid, capric
acid, lauric acid, palmitic acid, stearic acid, behenic acid,
erucic acid, oleic acid, linoleic acid, and salts thereof. In one
embodiment of the present invention, the HNP-containing composition
is substantially free of fatty acids and their salts. However,
fatty acids and salts thereof may be used in the HNP-containing
composition without departing from the spirit of the invention.
[0038] Examples of suitable polyhydric alcohols include, but are
not limited to, polyalkylene glycols, particularly polyethylene
glycol and polypropylene glycol; polylactic acid; copolymers
thereof; and blends thereof. Polyhydric alcohols of the present
invention generally have a weight average molecular weight
(M.sub.w) of greater than 500, such as from 500 to 20,000, and in
some cases from 1,000 to 20,000. In one embodiment, the polyhydric
alcohol is polyethylene glycol or a copolymer thereof, including
multi-armed polyethylene glycol polymers, such as those disclosed
in U.S. Pat. No. 6,371,975, the entire disclosure of which is
hereby incorporated herein by reference. Particularly suitable
multi-armed polyethylene glycols are those modified with glutaric
acid and hydroxysuccinimide ester groups, resulting in a 4-arm
polyethylene glycol succinimidyl glutarate having an M, of about
10,000. Such 4-arm polyethylene glycols are commercially-available
from Shearwater Polymers of Huntsville, Ala.
[0039] While not wishing to be bound by theory, it is believed that
polyhydric alcohols function as ionic plasticizers, which
plasticize the ionic regions or domains of the polymer without
plasticizing the non-ionic polymer backbone. They may also function
as amphiphilic plasticizers, plasticizing both the ionic and
non-ionic (i.e., olefinic) regions of the ionomer. Other suitable
plasticizers include, but are not limited to, alkylamines (e.g.,
methylamine, ethylamine, propylamine, butylamine, hexylamine,
octylamine, dimethylamine, trimethylamine, triethylamine,
methylethylamine, methyl-n-butylamine, tetramethylethylene diamine,
cyclohexylamine, and longer chain alkylamines, such as
dimethylstearylamine); alkanol amines (e.g., dimethylethanol amine,
diethylethanol amine, dipropylethanol amine, and dibutylethanol
amine); fatty acid amines (e.g., bisstearamides and alkylene
bis-fatty acid amides, such as ethylene bisstearamide); glycerol
and glycerol esters (e.g., glycerol acetate and glycerol
monostearate); butanediol; hexamethyl phosphoramide; N-ethyl
toluene sulfonamide; N,N-dimethylacetamide;
2,2-dimethyl-1,2-ethanediol; and dimethyl sulfoxide. One or more of
the following materials may also be used instead of, or in addition
to, polyhydric alcohol(s) in compositions of the present invention:
phthalate esters and modified phthalate esters (e.g., dioctyl
phthalate and dibutyl phthalate); phthalates of linear alcohols;
citrates (e.g., tributyl citrate and acetyl tributyl citrate);
monoesters and diesters of polyoxyethylene alkyl ethers;
polyoxyethylene alkylaryl ethers; polyoxyethylene alkylene ester
sulfates; polyoxyethylene alkyl phenol ether sulfates; and
polyoxyethylene sorbitan fatty acid esters (e.g., polyoxyethylene
sorbitan monolaurate).
[0040] Although polyhydric alcohols can be included in the polymer
resins of the present invention as described above, certain
polyhydric alcohols can be particularly suitable as ionic
plasticizers in accordance with one aspect of the present
invention. As such, in one embodiment, ionic plasticizers can be
alcohol esters, montanic acids, montanic acid esters, alkylene
bis-amines, zwitterionic compounds, salts thereof, and combinations
thereof. These ionic plasticizers can be used alone, or admixed
with other plasticizers such as the aforementioned polyhydric
alcohols and/of fatty acids.
[0041] In one specific embodiment, the ionic plasticizer can be a
polyalcohol ester. Non-limiting examples of suitable polyalcohol
esters can include polyalcohol stearate or oleate esters such as
glycerol monostearate, pentaerythritol distearate, glycerine
monooleate, glycerine dioleate, pentaerythritol tetrastearate,
pentaerythritol tetraisostearate, pentaerythritol tetraoleate,
neo-pentyl glycol dioleate, and combinations thereof. Many of these
polyalcohol esters are commercially-available as the Kemfluid
series (e.g., Kemfluid.RTM. 203, 203-4, 419, 219, 219-D, 223, 227,
and 402 from Undesa).
[0042] In another embodiment, the ionic plasticizer can be a
montanic acid, montanic acid ester, or salt thereof. Generally, the
montanic acid ester or salt thereof can be a reaction product of
montanic acid and an alcohol. The alcohol can most often include
C.sub.1-C.sub.4 alkanols, C.sub.1-C.sub.4 alkylene glycols,
glycerol, and combinations thereof. In one specific embodiment, the
montanic acid ester is octacosanoic acid-methyl ester.
Commercially-available montanic acids and their esters include
Licowax.RTM. E powders and flakes, Licowax.RTM. OP partially
saponified esters, Licowax.RTM. S, Licowax.RTM. E, Licowax.RTM. ET
montanic esters, Licomont.RTM.V CaV calcium salts of montanic acid,
Licomont.RTM. NaV sodium salts, and Licolub.RTM. WE 4, WE 40 esters
(all available from Clariant). Montanic acid is a C.sub.28-C.sub.32
straight-chain mono-carboxylic acid. Montanic acid esters have high
thermal stability and low volatility. An ester of montanic acid is
the reaction product of this long chain mono-carboxylic acid with
mono- or multi-functional organic alcohols. Such alcohols can
include, but are not limited to, methanol, ethanol, propanol,
ethylene glycol, propylene glycol, butylene glycol, and glycerol.
The carboxylic endgroup may optionally be completely or partially
saponified by reaction with bases such as sodium hydroxide or
calcium hydroxide. The stoichiometry of the reaction between
montanic acid and the alcohol can be adjusted so that the reaction
product can be a completely esterified montanic acid, partially
esterified montanic acid, completely reacted mono- or
multi-functional alcohol, or partially reacted mono- or
multi-functional alcohol, completely or partially saponified
carboxylic acid salt, or mixtures of these. The specific choice of
montanic acid or its esters can affect, among other things, the
viscosity of the composition and how miscible or immiscible it will
be in the HNP materials. Although ranges can vary somewhat,
montanic acid esters can generally be present in the polymer
composition from about 0.001 wt % to about 20 wt %, such as 0.01 wt
% to 10 wt %, and in some cases 0.01 wt % to about 5 wt %.
[0043] In another embodiment, the ionic plasticizer can be an
alkylene bis-amine such as a fatty acid amine. Non-limiting
examples of suitable fatty acid amines include bis-stearoyl ethyl
enedi amine, ethylene bisstearamide, oleamides (oleylamides), and
erucamide. Commercial examples of such fatty acid amines include
Licolub.RTM. FA 1 and Licowax.RTM. C (available from Clariant).
[0044] In another aspect of the present disclosure, the ionic
plasticizer can be a zwitterionic compound. Suitable zwitterionic
compounds can include at least one positive and one negative charge
covalently bonded on a common charge center (e.g., an atom or group
of atoms). One particular class of zwitterionic compounds has the
formula:
R.sub.1R.sub.2R.sub.3--Y.sup.+--R.sub.4--X.sup.- (formula 1)
where R.sub.1, R.sub.2, and R.sub.3 independently denote an alkyl-,
aryl-, alkaryl-, or aralkyl group having 1 to 30 carbon atoms.
These groups can be un-substituted, or wholly or partially
chlorinated or fluorinated, and can be optionally branched.
Specific examples include phenol and un-branched, un-substituted
alkyl group having 1 to 20 carbon atoms, such as phenyl, methyl or
alkyl having 12 to 20 carbon atoms. R.sub.4 denotes a bivalent
alkylene group having 1 to 30 carbon atoms and which can be
un-substituted or wholly or partially chlorinated or fluorinated
and optionally branched. Specific examples include un-branched,
un-substituted .alpha.,.alpha.-alkylene group C.sub.1-C.sub.5.
Further, Y denotes nitrogen or phosphorus, and X denotes
--SO.sub.3.sup.-, --COO.sup.-, PO.sub.3.sup.-, with
--SO.sub.3.sup.-, being particularly suitable. One specific example
of a suitable zwitterionic compound is
N,N-dimethyl-N-stearyl-N-(3-sulfopropyl)-ammonium betaine.
[0045] The amount of polyhydric alcohol present in the
HNP-containing compositions of the present invention is typically
at least 0.5 wt %, such as from 1 wt % to 15 wt %, and in some
cases from 1.5 wt % to 10 wt %, based on the total polymeric weight
of the composition. The amount of acid polymer present in the
HNP-containing compositions of the present invention is typically
at least 50 wt %, often from 50 wt % to 99.5 wt %, and in some
cases from 60 wt % to 98 wt %, based on the total polymeric weight
of the composition. Similarly, the amount of ionic plasticizer
present in the HNP-containing compositions can generally range from
0.1 wt % to 50 wt %, such as 1 wt % to 40 wt %, and in some cases
10 wt % to 35 wt %. As mentioned, the plasticizers used in
accordance with embodiments of the present disclosure can be
alcohol esters, montanic acids, montanic acid esters, alkylene
bis-amines, zwitterionic compounds, salts thereof, and combinations
thereof. That being said, other more conventional plasticizer may
or may not be present as well, e.g., fatty acids and/or polyhydric
alcohols. Some embodiments are devoid of these other plasticizers,
and other embodiments are co-formulated with these or other types
of plasticizers.
[0046] The HNP-containing compositions of the present invention may
also contain a melt flow modifier selected from polyesters,
polyacrylates, thermoplastic polyureas, polyethers, polyamides, and
combinations thereof. Such non-fatty acid melt flow modifiers
typically have an M.sub.w of from 1,000 to 100,000 and a melt flow
index of from 10 g/10 min to 1,000 g/10 min.
[0047] The HNP-containing compositions of the present invention can
also include one or more other additives. Suitable additives
include, but are not limited to, chemical blowing and foaming
agents, optical brighteners, coloring agents, fluorescent agents,
whitening agents, UV absorbers, light stabilizers, defoaming
agents, processing aids, mica, talc, nano-fillers, antioxidants,
stabilizers, softening agents, fragrance components, plasticizers,
impact modifiers, TiO.sub.2, acid copolymer wax, surfactants, and
fillers, such as zinc oxide, tin oxide, barium sulfate, zinc
sulfate, calcium oxide, calcium carbonate, zinc carbonate, barium
carbonate, clay, tungsten, tungsten carbide, silica, lead silicate,
regrind (recycled material), and mixtures thereof. Suitable
additives are more fully described in, for example, U.S. Patent
Application Publication No. 2003/0225197, the entire disclosure of
which is hereby incorporated herein by reference. Other optional
additives can include fibers, flakes, particulates, microspheres,
pre-expanded beads of glass, ceramic, metal or polymer, and the
like which may be optionally foamed. Depending on the additive,
such additives can be present in an amount of from 0 wt % to 60 wt
%, based on the total weight of the composition.
[0048] The cover layer, or any layer of a multiple layer cover, can
be formed of suitable polymers such as the HNP materials described
herein, polyurethanes, or polyureas. Most often, the outer cover
layer comprises a light stable polyurethane or polyurea, and an
inner cover layer or core layer will include the HNP materials
described herein.
[0049] As briefly summarized above, golf balls of the present
invention can be formed having a variety of internal
configurations. For example, golf balls of the present invention
can be wound, one-piece, two-piece, or multi-layer balls, wherein
at least one layer comprises an HNP-containing composition
described herein. In golf balls having two or more layers which
comprise an HNP-containing composition, the HNP-containing
composition of one layer may be the same or a different
HNP-containing composition as another layer. The layer(s)
comprising the HNP-containing composition can be any one or more of
a core layer, an intermediate layer, or a cover layer. Although
note required, the core can often include a center and an outer
core layer. Similarly, the cover layer can be a double layer cover
having an inner cover layer and an outer cover layer. The outer
core layer or the inner cover layer would both be considered
intermediate layers. Intermediate layers can also include thin
moisture barrier layers, coating layers, adhesive layers, etc.
[0050] Typically, golf balls of the present invention are
multi-layer balls having a compression molded rubber core, at least
one injection or compression molded intermediate layer which
comprises an HNP-containing composition, and a cast or reaction
injection molded polyurethane or polyurea outer cover layer. The
rubber core composition comprises a base rubber, a crosslinking
agent, a filler, and a co-crosslinking or initiator agent. Typical
base rubber materials include natural and synthetic rubbers,
including, but not limited to, polybutadiene and styrene-butadiene.
The crosslinking agent typically includes a metal salt, such as a
zinc salt or magnesium salt, of an acid having from 3 to 8 carbon
atoms, such as (meth) acrylic acid. The initiator agent can be any
known polymerization initiator which decomposes during the cure
cycle, including, but not limited to, dicumyl peroxide,
1,1-di-(t-butylperoxy) 3,3,5-trimethyl cyclohexane, a-a
bis-(t-butylperoxy) diisopropylbenzene, 2,5-dimethyl-2,5
di-(t-butylperoxy) hexane or di-t-butyl peroxide, and mixtures
thereof. Suitable types and amounts of base rubber, crosslinking
agent, filler, co-crosslinking agent, and initiator agent are more
fully described in, for example, U.S. Patent Application
Publication No. 2003/0144087, the entire disclosure of which is
hereby incorporated herein by reference. Reference is also made to
U.S. Patent Application Publication No. 2003/0144087, which is
incorporated herein by reference, for various ball constructions
and materials that can be used in golf ball core, intermediate, and
cover layers of the present invention.
[0051] Cover compositions of the present invention include
polyurethanes formed from the reaction product of at least one
polyisocyanate and at least one curing agent. The curing agent can
include, for example, one or more diamines, one or more polyols, or
a combination thereof. The at least one 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, when
polyols are described herein they may be suitable for use in one or
both components of the polyurethane material, i.e., as part of a
prepolymer and in the curing agent. The curing agent includes a
polyol curing agent preferably selected from the group consisting
of 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; trimethylol propane;
and combinations thereof.
[0052] Suitable polyurethane cover compositions of the present
invention also include those formed from the reaction product of at
least one isocyanate and at least one curing agent or the reaction
produce of at least one isocyanate, at least one polyol, and at
least one curing agent. Preferred isocyanates include those
selected from the group consisting of 4,4'-diphenylmethane
diisocyanate, polymeric 4,4'-diphenylmethane diisocyanate,
carbodiimide-modified liquid 4,4'-diphenylmethane diisocyanate,
4,4'-dicyclohexylmethane diisocyanate, p-phenylene diisocyanate,
toluene diisocyanate, isophoronediisocyanate, p-methylxylene
diisocyanate, m-methylxylene diisocyanate, o-methylxylene
diisocyanate, and combinations thereof. Preferred polyols include
those selected from the group consisting of polyether polyol,
hydroxy-terminated polybutadiene, polyester polyol,
polycaprolactone polyol, polycarbonate polyol, and combinations
thereof. Preferred curing agents include polyamine curing agents,
polyol curing agents, and combinations thereof. Polyamine curing
agents are particularly preferred. Preferred polyamine curing
agents include, for example, 3,5-dimethylthio-2,4-toluenediamine,
or an isomer thereof; 3,5-diethyltoluene-2,4-diamine, or an isomer
thereof; 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); trimethylene
glycol-di-p-aminobenzoate;
polytetramethyleneoxide-di-p-aminobenzoate; N,N'-dialkyldiamino
diphenyl methane; p,p'-methylene dianiline; phenylenediamine;
4,4'-methylene-bis-(2-chloroaniline);
4,4'-methylene-bis-(2,6-diethylaniline);
4,4'-diamino-3,3'-diethyl-5,5'-dimethyl diphenylmethane;
2,2',3,3'-tetrachloro diamino diphenylmethane;
4,4'-methylene-bis-(3-chloro-2,6-diethylaniline); and combinations
thereof.
[0053] The present invention is not limited by the use of a
particular polyisocyanate in the cover composition. Suitable
polyisocyanates include, but are not limited to,
4,4'-diphenylmethane diisocyanate ("MDI"); polymeric MDI,
carbodiimide-modified liquid MDI; 4,4'-dicyclohexylmethane
diisocyanate; p-phenylene diisocyanate ("PPDI"); toluene
diisocyanate ("TDI"); 3,3'-dimethyl-4,4'-biphenylene diisocyanate;
isophoronediisocyanate; hexamethylene diisocyanate; naphthalene
diisocyanate; xylene diisocyanate; p-tetramethylxylene
diisocyanate; m-tetramethylxylene diisocyanate; ethylene
diisocyanate; propylene-1,2-diisocyanate;
tetramethylene-1,4-diisocyanate; cyclohexyl diisocyanate;
1,6-hexamethylene-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;
naphthalene diisocyanate; anthracene diisocyanate; and combinations
thereof. Polyisocyanates are known to those of ordinary skill in
the art as having more than one isocyanate group, e.g., di-, tri-,
and tetra-isocyanate. Preferably, the polyisocyanate is selected
from MDI, PPDI, TDI, and combinations thereof. 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, combinations
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 than
conventional diisocyanates, i.e., the compositions of the invention
typically have less than about 0.1% free monomer 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.
[0054] The at least one polyisocyanate should have less than 14%
unreacted NCO groups. Preferably, the at least one polyisocyanate
has no greater than 8.5% NCO, more preferably from 2.5% to 8.0%,
even more preferably from 4.0% to 7.2%, and most preferably from
5.0% to 6.5%.
[0055] The present invention is not limited by the use of a
particular polyol in the cover composition. In one embodiment, the
molecular weight of the polyol is from about 200 to about 6000.
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. Particularly
preferred are polytetramethylene ether glycol ("PTMEG"),
polyethylene propylene glycol, polyoxypropylene glycol, and
combinations 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. Suitable polyester polyols include, but are not
limited to, polyethylene adipate glycol, polybutylene adipate
glycol, polyethylene propylene adipate glycol,
ortho-phthalate-1,6-hexanediol, and combinations thereof. The
hydrocarbon chain can have saturated or unsaturated bonds, or
substituted or unsubstituted aromatic and cyclic groups. 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 combinations
thereof. The hydrocarbon chain can have saturated or unsaturated
bonds, or substituted or unsubstituted aromatic and cyclic groups.
Suitable polycarbonates include, but are not limited to,
polyphthalate carbonate. The hydrocarbon chain can have saturated
or unsaturated bonds, or substituted or unsubstituted aromatic and
cyclic groups.
[0056] Polyamine curatives are also suitable for use in the curing
agent of polyurethane compositions 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-chloro
aniline); 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'-diamino-3,3'-diethyl-5,5'-dimethyl diphenylmethane; 2,2',
3,3'-tetrachloro diamino diphenylmethane;
4,4'-methylene-bis-(3-chloro-2,6-diethylaniline); trimethylene
glycol di-p-aminobenzoate; and combinations thereof. Preferably,
the curing agent of the present invention includes
3,5-dimethylthio-2,4-toluenediamine and isomers thereof, such as
Ethacure.RTM. 300 or, alternatively, Ethacure.RTM. 100 and 100 LC.
Suitable polyamine curatives, which include both primary and
secondary amines, preferably have weight average molecular weights
ranging from about 64 to about 2000.
[0057] At least one of a diol, triol, tetraol, or
hydroxy-terminated curative may be added to the 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-(4-hydroxyethyl)ether;
hydroquinone-di-(4-hydroxyethyl)ether; and combinations thereof.
Preferred hydroxy-terminated curatives include ethylene glycol;
diethylene glycol; 1,4-butanediol; 1,5-pentanediol; 1,6-hexanediol,
trimethylol propane, and combinations thereof. Preferably, the
hydroxy-terminated curative has a 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.
[0058] 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.
[0059] 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 inhomogeneous (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.
[0060] Suitable polyureas are further disclosed, for example, in
U.S. Pat. Nos. 5,484,870 and 6,835,794, the entire disclosures of
which are hereby incorporated herein by reference. Suitable
polyurethane-urea cover materials include polyurethane/polyurea
blends and copolymers comprising urethane and urea segments, as
disclosed in U.S. Patent Application Publication No. 2007/0117923,
the entire disclosure of which is hereby incorporated herein by
reference.
[0061] Various properties of the golf ball can dramatically affect
performance. These properties can be a result of the particular
materials and golf ball design chosen.
[0062] In one preferred embodiment the golf ball includes a dual
core (inner core and outer core layer) and a single cover layer.
The inner core and/or outer core comprise a polymer composition
that is a blend of a highly-neutralized acid polymer having acid
groups comprising at least 50 wt % of the polymer composition,
where 70% to 100% of the acid groups are neutralized; and an ionic
plasticizer being selected from the group consisting of alcohol
esters, montanic acids, montanic acid esters, alkylene bis-amines,
zwitterionic compounds, salts thereof, and combinations thereof.
The cover layer is preferably formed from a castable polyurethane
or polyurea. The inner core has a diameter of about 0.50 inches to
about 1.50 inches, more preferably about 0.75 inches to about 1.30
inches, most preferably about 1.00 inches to about 1.20 inches. The
outer core diameter is preferably about 1.55 inches to about 1.64
inches, more preferably about 1.58 inches to about 1.62 inches. In
this embodiment, the inner core has an Atti compression of about 60
or less, more preferably about 40 or less, and most preferably
about 30 or less. The inner core surface hardness is preferably
about 10 to about 50 Shore D, more preferably about 15 to about 40
Shore D, and most preferably about 20 to about 35 Shore D.
[0063] In this embodiment, the outer core layer surface hardness is
preferably about 20 to about 60 Shore D, more preferably about 25
to about 55 Shore D, and most preferably about 30 to about 50 Shore
D. The outer cover layer preferably has a thickness of about 0.015
inches to about 0.05 inches, more preferably about 0.02 inches to
about 0.04 inches, and most preferably about 0.025 inches to about
0.035 inches. The material hardness of the outer cover layer is
preferably about 30 to about 60 Shore D, more preferably about 35
to about 58 Shore D, and most preferably about 40 to about 55 Shore
D.
[0064] In a second preferred embodiment, the above golf ball
further includes an inner cover layer comprising a thermoplastic or
thermosetting material, more preferably a thermoplastic material,
and most preferably an ionomeric material. The inner cover layer,
which is disposed between the outer cover layer and the outer core
layer, preferably has a thickness of about 0.015 inches to about
0.05 inches, more preferably about 0.02 inches to about 0.04
inches, and most preferably about 0.025 inches to about 0.035
inches. The inner cover layer preferably has a material hardness of
about 55 to about 80 Shore D, more preferably about 57 to about 75
Shore D, and most preferably about 62 to about 72 Shore D. In this
embodiment, the outer core layer preferably has a diameter of about
1.51 inches to about 1.62 inches, more preferably about 1.53 inches
to about 1.60 inches, and most preferably about 1.55 inches to
about 1.58 inches.
[0065] Accordingly, the golf balls of the present invention can
have a center having a diameter of from 1.00 inches to 1.63 inches
and an Atti compression of from 40 to 160. Most often, the center
has a surface hardness of from 20 Shore D to 70 Shore D. When
present, the intermediate layer can generally have a material
hardness of from 30 Shore D to 80 Shore D. Although other
dimensions can be used, the intermediate layer typically has a
thickness of from 0.020 inches to 0.090 inches, more often from
0.010 inches to 0.060 inches.
[0066] Golf balls of the present invention generally also have a
coefficient of restitution of at least 0.790, such as at least
0.800, in some cases at least 0.805, and even other cases at least
0.810. Furthermore, an Atti compression of from 75 to 110, such as
from 90 to 100, can be particularly suitable. COR is defined as the
ratio of the rebound velocity to the inbound velocity when balls
are fired into a rigid plate. In determining COR, the inbound
velocity is understood to be 125 ft/s.
[0067] HNP-containing compositions of the present invention
typically have a flexural modulus of from 3,000 psi to 200,000 psi,
such as from 5,000 psi to 150,000 psi, in some cases from 10,000
psi to 125,000 psi, and in other cases from 10,000 psi to 100,000
psi. The material hardness of the HNP-containing compositions is
generally from 30 Shore D to 80 Shore D, more often from 40 Shore D
to 75 Shore D, and in some cases from 45 Shore D to 70 Shore D. The
notched izod impact strength of the HNP-containing compositions of
the present invention is generally at least 2 ft-lb/in, as measured
at 23.degree. C. according to ASTM D256.
[0068] As a guideline, in order to be processable, the
HNP-containing composition can have a melt flow index of at least
0.5 g/10 min. More particularly, the melt flow index of the
HNP-containing composition can be from 0.5 g/10 min to 10.0 g/10
min, such as from 1.0 g/10 min to 5.0 g/10 min, and in some cases
from 1.0 g/10 min to 4.0 g/10 min.
[0069] The present invention is not limited by any particular
method for making the HNP-containing composition. In one
embodiment, the composition is prepared by an extrusion process
utilizing a melt extruder, such as a single or twin screw extruder.
In a typical extruder process, the acid polymer(s), polyhydric
alcohol(s), and optional additives are fed, either simultaneously
or separately, into the extruder and melt blended at a temperature
typically within the range of from 200.degree. C. to 550.degree. C.
The cation source is concurrently or subsequently added to
neutralize the acid polymer(s) to a desired level. The acid
polymer(s) may be partially neutralized prior to contact with the
cation source. In another embodiment, the composition is prepared
by heating and reacting the acid polymer(s) and polyhydric alcohol
in solution at a temperature above the melting point of the
polymeric components. In still another embodiment, an unneutralized
ionomer can be blended with the ionic plasticizer and then
neutralized. Optionally, a partially neutralized ionomer can be
mixed with the plasticizer and subsequently additional cation added
to further neutralize the ionomer.
[0070] Similarly, the present invention is not limited by any
particular process for forming the golf ball layer(s). It should be
understood that the layer(s) can be formed by any suitable
technique including, but not limited to, injection molding,
compression molding, casting, and reaction injection molding.
[0071] The compositions of the present invention can provide
alternative routes to processable highly-neutralized polymers which
can be effective and inexpensive. Furthermore, the present
invention allows for a greater range of physical properties, e.g.
flexibility, softer/faster combinations, improved toughness,
increased scuff and shear resistance, and the like.
[0072] The foregoing detailed description describes the invention
with reference to specific exemplary embodiments. However, it will
be appreciated that various modifications and changes can be made
without departing from the scope of the present invention as set
forth in the appended claims. The detailed description is to be
regarded as merely illustrative, rather than as restrictive, and
all such modifications or changes, if any, are intended to fall
within the scope of the present invention as described and set
forth herein.
* * * * *