U.S. patent application number 13/470703 was filed with the patent office on 2012-09-06 for golf balls including crosslinked thermoplastic polyurethane.
This patent application is currently assigned to NIKE, INC.. Invention is credited to Hsin Cheng, Chien-Hsin Chou, Chung-Yu Huang, Yasushi Ichikawa, Hideyuki Ishii, Chen-Tai Liu.
Application Number | 20120225738 13/470703 |
Document ID | / |
Family ID | 42814319 |
Filed Date | 2012-09-06 |
United States Patent
Application |
20120225738 |
Kind Code |
A1 |
Ishii; Hideyuki ; et
al. |
September 6, 2012 |
Golf Balls Including Crosslinked Thermoplastic Polyurethane
Abstract
This disclosure relates to golf balls made from a crosslinked
thermoplastic polyurethane elastomer. The crosslinked thermoplastic
polyurethane elastomer includes crosslinks located in the hard
segments, where the crosslinks being the reaction product of
unsaturated bonds located in the hard segments as catalyzed by a
free radical initiator. The crosslinks may be formed from an
unsaturated diol as a chain extender. The unsaturated diol may be
trimethylolpropane monoallylether (TMPME). The golf ball may
include the crosslinked thermoplastic polyurethane elastomer in the
cover layer, in which case the cover layer may exhibit a high
degree of scuff resistance.
Inventors: |
Ishii; Hideyuki; (Portland,
OR) ; Cheng; Hsin; (Yunlin County, TW) ; Chou;
Chien-Hsin; (Yunlin County, TW) ; Huang;
Chung-Yu; (Tainan County, TW) ; Ichikawa;
Yasushi; (Tualatin, OR) ; Liu; Chen-Tai;
(Yunlin County, TW) |
Assignee: |
NIKE, INC.
Beaverton
OR
|
Family ID: |
42814319 |
Appl. No.: |
13/470703 |
Filed: |
May 14, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12827360 |
Jun 30, 2010 |
8193296 |
|
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13470703 |
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Current U.S.
Class: |
473/378 ;
525/453 |
Current CPC
Class: |
A63B 37/0041 20130101;
C08G 18/3206 20130101; C08G 18/6511 20130101; C08G 18/6705
20130101; A63B 37/0003 20130101; A63B 37/0087 20130101; A63B 37/12
20130101; A63B 37/0086 20130101; C08G 18/4854 20130101; A63B
37/0031 20130101; A63B 37/0024 20130101 |
Class at
Publication: |
473/378 ;
525/453 |
International
Class: |
A63B 37/12 20060101
A63B037/12; C08G 18/32 20060101 C08G018/32 |
Claims
1. A golf ball comprising: a crosslinked thermoplastic polyurethane
elastomer; the crosslinked thermoplastic polyurethane elastomer
including hard segments and soft segments; wherein the crosslinked
thermoplastic polyurethane elastomer includes crosslinks located in
the hard segments, the crosslinks being the reaction product of
unsaturated bonds located in an allyl side chain of an unsaturated
diol chain extender as catalyzed by a free radical initiator.
2. The golf ball of claim 1, wherein the crosslinked thermoplastic
polyurethane elastomer comprises an unsaturated diol, having two
primary hydroxyl groups and at least one allyl ether side group, of
the formula ##STR00004## in which R is alkyl group with or without
modified functional groups, and x and y are integers of 1 to 4.
3. The golf ball of claim 2, wherein a weight ratio of the free
radical initiator to the unsaturated diol chain extender is about
5:100.
4. The golf ball of claim 2, wherein the crosslinked thermoplastic
polyurethane elastomer is the reaction product formed from reacting
an organic isocyanate with a mixture of the following reactants:
(a) the unsaturated diol chain extender of the formula ##STR00005##
in which R is alkyl group with or without modified functional
groups, and x and y are integers of 1 to 4; wherein a weight ratio
of the crosslinked thermoplastic polyurethane elastomer to the
unsaturated diol chain extender is from about 100:0.1 to about
100:25; (b) a secondary chain extender, having at least two
reaction sites with isocyantes and having a molecular weight of
less than about 450; (c) a long chain polyol having a molecular
weight of between about 500 and about 4,000; and (d) a sufficient
degree amount of free radical initiator, so as to be capable of
generating free radicals that induce crosslinking structures in the
hard segments by free radical initiation.
5. The golf ball of claim 1, wherein the golf ball comprises a core
and a cover layer substantially surrounding the core; the cover
layer comprises an inner cover layer substantially surrounding the
core and an outer cover layer substantially surrounding the inner
cover layer; and the outer cover layer comprises the crosslinked
thermoplastic polyurethane elastomer having crosslinks located in
the hard segments.
6. The golf ball of claim 1, wherein the golf ball comprises a core
and a cover layer substantially surrounding the core; and the cover
layer comprises the crosslinked thermoplastic polyurethane
elastomer having crosslinks located in the hard segments.
7. A golf ball comprising: an inner core layer, an outer core layer
substantially surrounding the inner core layer, an inner cover
layer substantially surrounding the outer core layer, and an outer
cover layer substantially surrounding the inner cover layer;
wherein the outer cover layer comprises a crosslinked thermoplastic
polyurethane elastomer having crosslinks located in hard segments,
the crosslinks being the reaction product of unsaturated bonds
located in the hard segments as catalyzed by a free radical
initiator; and the golf ball satisfies the following requirements:
(1) the golf ball has a compression deformation of from about 2 to
about 4 millimeters under a load of 10 to 130 kilograms; (2) the
inner core layer has a coefficient of restitution at 40 meters per
second from about 0.79 to about 0.92, the coefficient of
restitution of the inner core being higher than that of the golf
ball.
8. The golf ball of claim 7, wherein the unsaturated bond is
located in a trimethylolpropane monoallylether chain extender.
9. The golf ball of claim 7, wherein the outer cover layer has a
Shore D hardness of between about 20 and about 75.
10. The golf ball of claim 7, wherein the free radical initiator is
selected from the group consisting of peroxides, sulfurs, and
sulfides.
11. The golf ball of claim 7, the outer cover layer has a flexural
modulus of from about 1 kpsi to about 150 kpsi.
12. The golf ball of claim 7, wherein the crosslinked thermoplastic
polyurethane elastomer comprises an unsaturated diol, having two
primary hydroxyl groups and at least one allyl ether side group, of
the formula ##STR00006## in which R is alkyl group with or without
modified functional groups, and x and y are integers of 1 to 4.
13. The golf ball of claim 7, wherein: the crosslinked
thermoplastic polyurethane elastomer is the reaction product formed
from reacting an organic isocyanate with a mixture of the following
reactants: (a) an unsaturated diol chain extender of the formula
##STR00007## in which R is alkyl group with or without modified
functional groups, and x and y are integers of 1 to 4; wherein a
weight ratio of the crosslinked thermoplastic polyurethane
elastomer to the unsaturated diol chain extender is from about
100:0.1 to about 100:25; (b) a secondary chain extender, having at
least two reaction sites with isocyantes and having a molecular
weight of less than about 450; (c) a long chain polyol having a
molecular weight of between about 500 and about 4,000; and (d) a
sufficient degree amount of free radical initiator, so as to be
capable of generating free radicals that induce crosslinking
structures in the hard segments by free radical initiation, wherein
the free radical initiator is present in the crosslinked
thermoplastic polyurethane elastomer in a weight ratio of free
radical initiator to unsaturated diols of from about 0.1:100 to
about 100:100.
14. A golf ball comprising: an inner core layer, an outer core
layer substantially surrounding the inner core layer, an inner
cover layer substantially surrounding the outer core layer, and an
outer cover layer substantially surrounding the inner cover layer;
wherein the outer cover layer comprises a crosslinked thermoplastic
polyurethane elastomer having crosslinks located in hard segments,
the crosslinks being the reaction product of unsaturated bonds
located in the hard segments as catalyzed by a free radical
initiator; and the golf ball satisfies the following requirements:
(1) the outer cover layer has a Shore D hardness from about 20 to
about 75; and (2) the outer cover layer has a flexural modulus of
from about 1 kpsi to about 150 kpsi.
15. The golf ball of claim 14, wherein the golf ball has a
compression deformation of from about 2 to about 4 millimeters
under a load of 10 to 130 kilograms.
16. The golf ball of claim 14, wherein the inner core layer has a
coefficient of restitution at 40 meters per second from about 0.79
to about 0.92, the coefficient of restitution of the inner core
being higher than that of the golf ball.
17. The golf ball of claim 14, wherein the crosslinked
thermoplastic polyurethane elastomer comprises unsaturated diols as
chain extenders.
18. The golf ball of claim 17, wherein the weight ratio of the
crosslinked thermoplastic polyurethane elastomer to the unsaturated
diols is from 100:0.1 to 100:15.
19. The golf ball of claim 14, wherein the crosslinked
thermoplastic polyurethane elastomer comprises an unsaturated diol,
having two primary hydroxyl groups and at least one allyl ether
side group, of the formula ##STR00008## in which R is alkyl group
with or without modified functional groups, and x and y are
integers of 1 to 4.
20. The golf ball of claim 14, wherein the crosslinked
thermoplastic polyurethane elastomer includes crosslinks formed
from allyl ether side groups, and the crosslinked thermoplastic
polyurethane elastomer is the reaction product formed from reacting
an organic isocyanate with a mixture of the following reactants:
(a) an unsaturated diol, having two primary hydroxyl groups and at
least one allyl ether side group, of the formula ##STR00009## in
which R is alkyl group with or without modified functional groups,
and x and y are integers of 1 to 4; (b) a chain extender, having at
least two reaction sites with isocyantes and having a molecular
weight of less than about 450; (c) a long chain polyol having a
molecular weight of between about 500 and about 4,000; and (d) a
sufficient amount of free radical initiator, so as to be capable of
generating free radicals that induce crosslinking structures in the
hard segments by free radical initiation.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application is a Continuation of U.S. Pat. No. ______,
currently U.S. application Ser. No. 12/827,360, entitled "Golf
Balls Including Crosslinked Thermoplastic Polyurethane", filed on
Jun. 30, 2012 and allowed on Apr. 12, 2012, the disclosure of which
is hereby incorporated by reference in its entirety.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to golf balls and their
manufacture, and in particular to golf balls having thermoplastic
polyurethane covers.
[0004] 2. Description of Related Art
[0005] Golf ball covers are generally divided into two types:
thermoplastic covers and thermoset covers. Thermoplastic polymer
materials may be reversibly melted, and so may be used in a variety
of manufacturing techniques such as compression molding that take
advantage of this property. On the other hand, thermoset polymer
materials are generally formed by mixing two or more components to
form a cured polymer material that cannot be re-melted or
re-worked. Each type of polymer material present advantages and
disadvantages when used to manufacture golf balls.
[0006] Thermoplastic materials for golf ball covers can be usually
include ionomer resin, highly neutralized acid polymer composition,
polyamide resin, polyester resin, polyurethane resin, and mixtures
thereof. Among these, ionomer resin and polyurethane resin are
popular materials for golf ball covers.
[0007] Ionomer resins, such as Surlyns.RTM. (commercially available
from E. I. DuPont de Nemours and Company), have conventionally been
used for golf ball covers. For example, Dunlop Rubber Company
obtained the first patent on the use of Surlyn.RTM. for the cover
of a golf ball, U.S. Pat. No. 3,454,280 issued Jul. 8, 1969. Since
then, there have been a number of disclosures on the use of ionomer
resins in the cover composition of a golf ball, for example, U.S.
Pat. Nos. 3,819,768, 4,323,247, 4,526,375, 4,884,814 and
4,911,451.
[0008] However, ionomer resin covered golf balls suffer from the
problem that the cover surface may be scraped off by grooves on a
clubface during repeated shots, particularly with irons. In other
words, ionomer covers have poor scuff resistance. Also, ionomer
covered balls usually have inferior spin and feel properties as
compared to balata rubber or polyurethane covered balls. The use of
softer ionomer resins for the cover will improve spin and feel to
some extent, but will also compromise the resilience of the golf
balls because such balls usually have a lower coefficient of
restitution (C.O.R.). Furthermore, the scuff resistance of such
softer ionomer covers is often still not satisfactory.
[0009] Thermoplastic polyurethane elastomers may also be used as
the cover material, as described in (for example) U.S. Pat. Nos.
3,395,109, 4,248,432 and 4,442,282. However, the thermoplastic
polyurethane elastomers disclosed therein do not satisfy all the
requirements of moldability, hitting feel, control, resilience, and
scuff resistance upon iron shots.
[0010] On the other hand, thermoset polymer materials such as
polyurethane elastomers, polyamide elastomers, polyurea elastomers,
diene-containing polymer, crosslinked metallocene catalyzed
polyolefin, and silicone, may also be used to manufacture golf
balls. Among these materials, thermoset polyurethane elastomers are
popular.
[0011] Many attempts, such as are described in U.S. Pat. Nos.
3,989,568, 4,123,061, 5,334,673, and 5,885,172, have been made to
use thermoset polyurethane elastomers as a substitute for balata
rubber and ionomer resins. Thermosetting polyurethane elastomers
are relatively inexpensive and offer good hitting feel and good
scuff resistance. Particularly, thermoset polyurethane elastomers
may present improvements in the scuff resistance as compared to
softened ionomer resin blends. However, thermoset materials require
complex manufacturing processes to introduce the raw material and
then effect a curing reaction, which causes the manufacturing
process to be less efficient.
[0012] Accordingly, for the foregoing reasons, there is a need to
develop a golf ball cover material with good scuff resistance that
can be efficiently manufactured. There is a need in the art for a
system and method that addresses the shortcomings of the prior art
discussed above.
SUMMARY OF THE INVENTION
[0013] In one aspect, this disclosure provides a golf ball
comprising: a crosslinked thermoplastic polyurethane elastomer; the
crosslinked thermoplastic polyurethane elastomer including hard
segments and soft segments; wherein the crosslinked thermoplastic
polyurethane elastomer includes crosslinks located in the hard
segments, the crosslinks being the reaction product of unsaturated
bonds located in the hard segments as catalyzed by a free radical
initiator.
[0014] In a particular embodiment of the above golf ball, this
disclosure provides a golf ball wherein the crosslinked
thermoplastic polyurethane elastomer includes crosslinks formed
from allyl ether side groups, and the crosslinked thermoplastic
polyurethane elastomer is the reaction product formed from reacting
an organic isocyanate with a mixture of the following reactants:
(a) an unsaturated diol, having two primary hydroxyl groups and at
least one allyl ether side group, of the formula
##STR00001##
[0015] in which R is alkyl group with or without modified
functional groups, and x and y are integers of 1 to 4; (b) a chain
extender, having at least two reaction sites with isocyantes and
having a molecular weight of less than about 450; (c) a long chain
polyol having a molecular weight of between about 500 and about
4,000; and (d) a sufficient degree of free radical initiator, so as
to be capable of generating free radicals that induce crosslinking
structures in the hard segments by free radical initiation.
[0016] In another aspect, the present disclosure provides a golf
ball comprising: an inner core layer, an outer core layer
substantially surrounding the inner core layer, an inner cover
layer substantially surrounding the outer core layer, and an outer
cover layer substantially surrounding the inner cover layer;
wherein the outer cover layer comprises a crosslinked thermoplastic
polyurethane elastomer having crosslinks located in hard segments,
the crosslinks being the reaction product of unsaturated bonds
located in the hard segments as catalyzed by a free radical
initiator; and the golf ball satisfies the following requirements:
(1) the golf ball has a compression deformation of from about 2 to
about 4 millimeters under a load of 10 to 130 kilograms; (2) the
inner core layer has a coefficient of restitution at 40 meters per
second from about 0.79 to about 0.92, the coefficient of
restitution of the inner core being higher than that of the golf
ball; (3) the outer cover layer has a Shore D hardness from about
20 to about 75; and (4) the outer cover layer has a flexural
modulus of from about 1 kpsi to about 150 kpsi.
[0017] Other systems, methods, features and advantages of the
invention will be, or will become, apparent to one of ordinary
skill in the art upon examination of the following figures and
detailed description. It is intended that all such additional
systems, methods, features and advantages be included within this
description and this summary, be within the scope of the invention,
and be protected by the following claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] The invention can be better understood with reference to the
following drawings and description. The components in the figures
are not necessarily to scale, emphasis instead being placed upon
illustrating the principles of the invention. Moreover, in the
figures, like reference numerals designate corresponding parts
throughout the different views.
[0019] FIG. 1 shows a representative golf ball in accordance with
this disclosure, the golf ball being of a two-piece
construction;
[0020] FIG. 2 shows a second representative golf ball, having an
inner cover layer and an outer cover layer;
[0021] FIG. 3 shows a third representative golf ball, having an
inner core and an outer core;
[0022] FIG. 4 shows a fourth representative golf ball, having an
inner core, an outer core, an inner cover layer, and an outer cover
layer.
DETAILED DESCRIPTION
[0023] Generally, this disclosure provides golf balls manufactured
from a crosslinked thermoplastic polyurethane, where the crosslinks
are formed in the hard segments. Any layer of the golf ball may be
made from the crosslinked thermoplastic polyurethane, and in
particular embodiments the cover is made from the crosslinked
thermoplastic polyurethane. As a result of these particular
crosslinks, the cover's scuff resistance may be greatly
improved.
[0024] Except as otherwise discussed herein below, any golf ball
discussed herein may generally be any type of golf ball known in
the art. Namely, unless the present disclosure indicates to the
contrary, a golf ball may generally be of any construction
conventionally used for golf balls, and may be made of any of the
various materials known to be used in golf ball manufacturing.
[0025] FIG. 1 shows a golf ball 100 in accordance with a first
embodiment of the present disclosure. Golf ball 100 is a two piece
golf ball. Specifically, golf ball 100 includes cover layer 110
substantially surrounding core 120. In golf ball 100, either or
both of cover 110 or core 120 may be made of a crosslinked
thermoplastic polyurethane elastomer. In particular embodiments,
cover 110 comprises the crosslinked thermoplastic polyurethane
elastomer.
[0026] The crosslinked thermoplastic polyurethane elastomer may
include hard segments and soft segments, as thermoplastic
polyurethanes are known to include. Thermoplastic polyurethanes are
generally made up of (1) a long chain polyol, (2) a relatively
short chain extender, and (3) a diisocyanate. Once reacted, the
portions of the polymer chain made up of the chain extender and
diisocyanate generally align themselves into semi-crystalline
structures through weak (i.e., non-covalent) association, such as
through Van der Waals forces, dipole-dipole interactions or
hydrogen bonding. These portions are commonly referred to as the
hard segments, because the semi-crystalline structure is harder
than the amorphous portions made up of the long chain polyol.
[0027] The crosslinked thermoplastic polyurethane may include
crosslinks located specifically in the hard segments. These
crosslinks may be the reaction product of unsaturated bonds located
in the hard segments, as catalyzed by a free radical initiator.
These unsaturated bonds may be introduced into the hard segments by
the use of unsaturated diols as chain extenders. In particular
embodiments, the crosslinks may be formed from allyl ether side
groups present in the hard segments.
[0028] In specific embodiments, the crosslinked thermoplastic
polyurethane elastomer may be derived from reacting an organic
isocyanate with a mixture of:
[0029] (a) an unsaturated diol, having two primary hydroxyl groups
and at least one allyl ether side group, of the formula
##STR00002##
[0030] in which R is alkyl group with or without modified
functional groups, and x and y are integers of 1 to 4;
[0031] (b) a chain extender, having at least two reaction sites
with isocyanates and having a molecular weight of less than about
450;
[0032] (c) a long chain polyol having a molecular weight of between
about 500 and about 4,000; and
[0033] (d) a sufficient degree of free radical initiator, so as to
be capable of generating free radicals that induce crosslinking
structures in the hard segments by free radical initiation.
[0034] Each of the above listed reactants will be discussed in
further detail, with the understanding that any particular
embodiment of a specific reactant may be mixed and matched with any
other specific embodiment of another reactant according to the
general formulation above. Furthermore, any reactant may generally
be used in combination with other reactants of the same type, such
that any list herein may be assumed to include mixtures thereof,
unless otherwise specified.
[0035] The organic isocyanate may include any of the known
aromatic, aliphatic, and cycloaliphatic di- or polyisocyanates.
Examples of suitable isocyanates include: 2,2'-, 2,4'- (and
particularly) 4,4-diphenylmethane diisocyanate, and isomeric
mixtures thereof; polyphenylene polymethylene
polyisocyanates(poly-MDI, PMDI); 2,4- and 2,6-toluene
diisocyanates, and isomeric mixtures thereof such as an 80:20
mixture of the 2,4- and 2,6-isomers; the saturated, isophorone
diisocyanate; 1,4-diisocyanatobutane; 1,5-diisocyanatopentane;
1,6-diisocyanatohexane; 1,4-cyclohexane diisocyanate;
cycloaliphatic analogs of PMDI; and the like.
[0036] Suitable chain extenders may include the common diols, such
as ethylene glycol, diethylene glycol, triethylene glycol,
propylene glycol, dipropylene glycol, tripropylene glycol,
1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, 1,10-decanediol,
neopentyl glycol, dihydroxyethoxy hydroquinone,
1,4-cyclo-hexanedimethanol, 1,4-dihydroxycyclohexane, and the like.
Minor amounts of crosslinking agents such as glycerine,
trimethylolpropane, diethanolamine, and triethanolamine may be used
in conjunction with the diol chain extenders.
[0037] In addition to the common diol chain extenders, diamines and
amino alcohols may also be used. Examples of suitable diamines
include aliphatic, cycolaliphatic or aromatic diamines. In
particular, a diamine chain extender may be ethylene diamine,
hexamethylene diamine, 1,4-cyclohexyene diamine, benzidine, toluene
diamine, diaminodiphenyl methane, the isomers of phenylene diamine
or hydrazine. Aromatic amines may also be used, such as MOCA
(4,4'-methylene-bis-o-chloroaniline), M-CDEA
(4,4'-methylenebis(3-chloro-2-6-diethyl-laniline)). Examples of
suitable amino alcohols are ethanol amine, N-methylethanolamine,
N-butylethanolamine, N-oleyethanolamine,
N-cyclohexylisopropanolamine, and the like. Mixtures of various
types of chain extenders may also be used to form the crosslinked
thermoplastic polyurethane.
[0038] The long chain polyol ("the polyol") may generally be a
polyester polyol or a polyether polyol. Accordingly, the
crosslinked thermoplastic polyurethane may be either general type
of polyurethane: a polyether based polyurethane elastomer or a
polyester based polyurethane elastomer, or mixtures thereof.
[0039] The long chain polyol may be a polyhydroxy compound having a
molecular weight between 500 and 4,000. Suitable long chain polyols
may generally include linear polyesters, polyethers,
polycarbonates, polylactones (e.g., c-caprolactone), and mixtures
thereof. In addition to polyols having hydroxyl terminal groups,
the polyol may include carboxyl, amino or mercapto terminal
groups.
[0040] Polyesters polyols are produced by the reaction of
dicarboxylic acids and diols or esterifiable derivative thereof.
Examples of suitable dicarboxylic acids include succinic acid,
glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic
acid, decanedicarboxylic acid, maleic acid, fumaric acid, phthalic
acid, isophthalic acid, and terephthalic acid. Examples of suitable
diols include ethanediol, diethylene glycol, 1,2- and
1,3-propanediol, dipropylene glycol, 1,4-butanediol,
1,5-pentanediol, 1,6-hexanediol, 1,10-decanediol, glycerine and
trimethylolpropanes, tripropylene glycol, tetraethylene glycol,
tetrapropylene glycol, tetramethylene glycol,
1,4-cyclohexane-dimethanol, and the like. Both of the dicarboxylic
acids and diols can be used individually or in mixtures to make
specific polyesters in the practice applications.
[0041] Polyether polyols are prepared by the ring-opening addition
polymerization of an alkylene oxide with an initiator of a
polyhydric alcohol. Examples of suitable polyether polyols are
polypropylene glycol (PPG), polyethylene glycol (PEG),
polytetramethylene ether glycol (PTMEG). Block copolymers such as
combinations of polyoxypropylene and polyoxyethylene glycols,
poly-1,2-oxybutylene and polyoxyethylene glycols,
poly-1,4-tetramethylene and polyoxyethylene glycols are also
preferred in the present invention.
[0042] Polycarbonate polyols are made through a condensation
reaction of diols with phosgene, chloroformic acid ester, dialkyl
carbonate or diallyl carbonate. Examples of diols in the suitable
polycarbonate polyols of the crosslinked thermoplastic polyurethane
elastomers are ethanediol, diethylene glycol, 1,3-butanediol,
1,4-butanediol, 1,6-hexanediol, neopentylglycol, and
1,5-pentanediol.
[0043] The crosslinked thermoplastic polyurethane elastomer may
comprise a sufficient degree of free radical initiator so as to be
capable of inducing crosslinking structures in the hard segments by
free radical initiation. The free radical initiator may generate
free radicals through thermal cleavage or UV radiation. When the
half-life of the free radical initiator and its operation
temperature are considered in the manufacturing process, the weight
ratio of initiators to unsaturated diols may be from 0.1:100 to
100:100. In particular embodiments, the weight ratio of free
radical initiator to unsaturated diols may be about 5:100.
[0044] A variety of known free radical initiators may be used as
the radical source in order to make the present polyurethane
elastomer having a crosslinking structure. Suitable radical
initiators may include peroxides, sulfurs, and sulfides, and
peroxides may be particularly suitable in some embodiments. The
peroxides may be aliphatic peroxides or and aromatic peroxides, or
mixtures thereof. Aromatic peroxides, such as diacetylperoxide,
di-tert-butypperoxide, dicumylperoxide, dibenzoylperoxide,
2,5-dimethyl-2,5-di(benzoylperoxy)hexane,
2,5-dimethyl-2,5-di(butylperoxy)-3-hexyne,
2,5-bis-(t-butylperoxy)-2,5-dimethyl hexane,
n-butyl-4,4-bis(t-butylperoxyl)valerate,
1,4-bis-(t-butylperoxyisopropyl)-benzene, t-butyl peroxybenzoate,
1,1-bis-(t-butylperoxy)-3,3,5 tri-methylcyclohexane, and
di(2,4-dichloro-benzoyl) may be used as the free radical initiator
in some embodiments.
[0045] The unsaturated diol may generally be any diol having at
least one unsaturated bond. As is generally known, an unsaturated
bond may be a double bond between two carbon atoms (as in an
alkene) or a triple bond (as in an alkyne). In particular
embodiments, the unsaturated diol may have two primary alcohol
groups. The presence of two primary alcohol groups may result in
favorable reaction kinetics, such that the crosslinked
thermoplastic polyurethane may be formed in an easily controlled
"one step" continuous process.
[0046] In particular embodiments, the unsaturated diol may have two
primary hydroxyl groups and at least one allyl ether side group, so
as to be of the formula:
##STR00003##
[0047] in which R is alkyl group with or without modified
functional groups, and x and y are integers of 1 to 4. In
particular embodiments, x and y may both have values of 1, 2, 3 or
4. In other embodiments, x and y may each have different values of
between 1 and 4.
[0048] In one particular embodiment, the unsaturated diol may be
trimethylolpropane monoallylether ("TMPME"). TMPME may also be
named "trimethylol propane monoallyl ether", "trimethylol propane
monoallylether", or "trimethylolpropane monoallyl ether." TMPME has
CAS no. 682-11-1. TMPME may also be referred to as 1,3-Propanediol,
2-ethyl-2-[(2-propen-1-yloxy)methyl] or as
2-allyloxymethyl-2-ethyl-1,3-propanediol. TMPME is commercially
available from Perstorp Specialty Chemicals AB.
[0049] Other suitable compounds that may be used as the unsaturated
diol of formula (1) may include: 1,3-Propanediol,
2-(2-propen-1-yl)-2-[(2-propen-1-yloxy)methyl]; 1,3-Propanediol,
2-methyl-2-[(2-propen-1-yloxy)methyl]; 1,3-Propanediol,
2,2-bis[(2-propen-1-yloxy)methyl; and 1,3-Propanediol,
2-[(2,3-dibromopropoxy)methyl]-2-[(2-propen-1-yloxy)methyl].
Further compounds within the scope of formula (1) may be known to a
person having ordinary skill in the art, and may be used in the
present disclosure.
[0050] The weight ratio of crosslinked thermoplastic polyurethane
elastomer to the unsaturated diols may generally be from about
100:0.1 to about 100:25. In particular embodiments, the weight
ratio of crosslinked thermoplastic polyurethane elastomer to the
unsaturated diols may be about 100:10. Furthermore, the NCO index
of the reactants making up the crosslinked thermoplastic
polyurethane elastomer may be from about 0.9 to about 1.3. As is
generally known, the NCO index is the molar ratio of isocyanate
functional groups to active hydrogen containing groups. In
particular embodiments, the NCO index may be about 1.0.
[0051] Optionally, the crosslinked thermoplastic polyurethane
elastomer may include further components such as fillers and/or
additives. Fillers and additives may be used based on any of a
variety of desired characteristics, such as enhancement of physical
properties, UV light resistance, and other properties. For example,
to improve UV light resistance, the crosslinked thermoplastic
polyurethane elastomer may include at least one light stabilizer.
Light stabilizers may include hindered amines, UV stabilizers, or a
mixture thereof.
[0052] Inorganic or organic fillers can be also added to the
crosslinked thermoplastic polyurethane elastomer. Suitable
inorganic fillers may include silicate minerals, metal oxides,
metal salts, clays, metal silicates, glass fibers, natural fibrous
minerals, synthetic fibrous minerals or a mixture thereof. Suitable
organic fillers may include carbon black, fullerene and/or carbon
nanotubes, melamine colophony, cellulose fibers, polyamide fibers,
polyacrylonitrile fibers, polyurethane fibers, polyester fibers
based on aromatic and/aliphatic dicarboxylic acid esters, carbon
fibers or a mixture thereof. The inorganic and organic fillers may
be used individually or as a mixture thereof. The total amount of
the filler may be from about 0.5 to about 30 percent by weight of
the polyurethane components.
[0053] Flame retardants may also be used to improve the flame
resistance of the crosslinked thermoplastic polyurethane elastomer.
Suitable flame retardants may include organic phosphates, metal
phosphates, metal polyphosphates, metal oxides (such as aluminum
oxide hydrate, antimony trioxide, arsenic oxide), metal salts (such
as calcium sulfate, expandable graphite), and cyanuric acid
derivatives (such as melamine cyanurate). These flame retardants
may be used individually or as a mixture thereof, and the total
amount of the flame retardant may be from about 10 to about 35
percent by weight of the polyurethane components.
[0054] To improve toughness and compression rebound, the
crosslinked thermoplastic polyurethane elastomer may include at
least one dispersant, such as a monomer or oligomer comprising
unsaturated bonds. Examples of suitable monomers include styrene,
acrylic esters; suitable oligomers include di- and
tri-acrylates/methacrylates, ester acrylates/methacrylates,
urethane or urea acrylates/methacrylates.
[0055] If the outermost layer of a golf ball comprises the
crosslinked thermoplastic polyurethane elastomer, then the
crosslinked thermoplastic polyurethane elastomer may includes at
least one white pigment to aid in better visibility. The white
pigment may be selected from the group consisting of titanium
dioxide, zinc oxide or a mixture thereof.
[0056] The crosslinked thermoplastic polyurethane elastomer may
generally be formed by a single-screw, twin-screw, or a batch
method in order to mix and react all of the ingredients described
above. The products of the reaction process may be in the form of
pallets or grounded chips.
[0057] If a single-crew or twin-screw process is used, the dwell
times of the molten reaction mixture in the screw extruder may
generally be in the range of from about 0.3 to about 10 minutes,
and in some embodiments may be from about 0.4 to about 4 minutes.
The temperature of the screw housing may be in the range of about
70 degrees Celsius to 280 degrees Celsius. The melt leaving the
extruder may be chilled and broken down into small pieces using any
method for the following injection or extrusion applications.
[0058] If a batch method is used to form the crosslinked
thermoplastic polyurethane elastomer, all the components are molten
and mixed together with a high agitated stir at a temperature in
the range of about 70 degrees Celsius to 120 degrees Celsius for
about 1 to about 3 minutes. Subsequently, the mixture is subjected
to a post curing process at a temperature in the range of about 70
degrees Celsius to 150 degrees Celsius for about 5 to about 18
hours. The products made by this batch method may be ground into
the form of chips for an injection or extrusion application.
[0059] FIG. 2 shows a golf ball 200 in accordance with a second
embodiment of the present disclosure. Golf ball 200 includes a core
230, an inner cover layer 220 substantially surrounding core 230,
and an outer cover layer 210 substantially surrounding inner cover
220. Any layer of golf ball 200 may comprise the crosslinked
thermoplastic polyurethane elastomer described above.
[0060] In some embodiments, both inner cover layer 220 and outer
cover layer 210 comprise the crosslinked thermoplastic polyurethane
elastomer. In other embodiments, either inner cover layer 220 or
outer cover layer 210 comprises the crosslinked thermoplastic
polyurethane elastomer. In still other embodiments, outer cover
layer 210 in particular comprises the crosslinked thermoplastic
polyurethane elastomer. In these embodiments, outer cover layer 210
may have a surface Shore D hardness of from about 20 to about 75,
or from about 40 to about 65. Outer cover layer 210 may have a
flexural modulus of about 1 to about 150 kpsi according to ASTM
D790.
[0061] FIG. 3 shows a golf ball 300 in accordance with a third
embodiment of the present disclosure. Golf ball 300 includes an
inner core layer 330, an outer core layer 320 substantially
surrounding inner core layer 330, and a cover layer 310
substantially surrounding outer core layer 320. Any layer of golf
ball 300 may include the crosslinked thermoplastic polyurethane
elastomer described above. In some embodiments, cover layer 310
comprises the crosslinked thermoplastic polyurethane elastomer. As
with cover layer 210, cover layer 310 may have a surface Shore D
hardness of from about 20 to about 75, or from about 40 to about
65. Cover layer 310 may also have a flexural modulus of from about
1 to about 150 kpsi according to ASTM D790.
[0062] FIG. 4 shows a golf ball 400 in accordance with a fourth
embodiment of the present disclosure. Golf ball 400 includes an
inner core layer 440, an outer core layer 430 substantially
surrounding inner core layer 440, an inner cover layer 420
substantially surrounding outer core layer 430, and an outer cover
layer 410 substantially surrounding inner cover layer 420. Any
layer of golf ball 400 may include the crosslinked thermoplastic
polyurethane elastomer described above.
[0063] In some embodiments, both inner cover layer 420 and outer
cover layer 410 comprise the crosslinked thermoplastic polyurethane
elastomer. In other embodiments, either inner cover layer 420 or
outer cover layer 410 may include the crosslinked thermoplastic
polyurethane elastomer. In specific embodiments, outer cover layer
410 comprises the crosslinked thermoplastic polyurethane elastomer.
In such embodiments, outer cover layer 410 may have a surface Shore
D hardness of from about 20 to about 75, or from about 40 to about
65. Outer cover layer 410 may also have a flexural modulus of 1 to
150 kpsi according to ASTM D790.
[0064] The construction of the golf ball according to the present
disclosure is not limited to the aforementioned embodiments. A golf
ball in accordance with this disclosure may generally take any
construction, such as a regulation or non-regulation construction.
Regulation golf balls are golf balls which meet the Rules of Golf
as approved by the United States Golf Association (USGA).
[0065] The crosslinked thermoplastic polyurethane elastomer
described variously above may be used to make golf balls by
injection molding or compression molding. Injection molding may be
used in particular embodiments in order to achieve increased
productivity. Generally, the free radical initiator may be added to
the polymer mixture at any of several stages during manufacturing.
For example, the radical initiator may be added during extrusion of
the polymer mixture, or during compression molding. Similarly, the
free radical initiator may be activated so as to form crosslinks
during any of several stages of manufacturing. For example, the
free radical initiator may be activated by heating during an
extrusion process.
[0066] For any ball layer(s) other than the layer(s) comprising the
crosslinked thermoplastic polyurethane elastomer, suitable
materials can be selected from any of the various materials known
to be used in golf ball manufacturing. Specifically, such other
materials may be selected from the following groups: (1)
thermoplastic materials selected from the group consisting of
ionomer resin, highly neutralized acid polymer composition,
polyamide resin, polyester resin, polyurethane resin and a mixture
thereof; or (2) thermoset materials selected from the group
consisting of polyurethane elastomer, polyamide elastomer, polyurea
elastomer, diene-containing polymer (such as polybutadiene),
crosslinked metallocene catalyzed polyolefin, silicone, and a
mixture thereof.
[0067] For example, in embodiments where the core construction is
multilayered, the choice of the material making up the inner core
layer 330 (as shown in FIG. 3) or inner core layer 440 (as shown in
FIG. 4) is not particularly limited. The material making up inner
core layer 330 or inner core layer 440 may be selected from the
following groups: (1) thermoplastic materials selected from the
group consisting of ionomer resin, highly neutralized acid polymer
composition, polyamide resin, polyester resin, polyurethane resin
and a mixture thereof; or (2) thermoset materials selected from the
group consisting of polyurethane elastomer, polyamide elastomer,
polyurea elastomer, diene-containing polymer (such as
polybutadiene), crosslinked metallocene catalyzed polyolefin,
silicone, and a mixture thereof.
[0068] Among the various thermoplastic and thermoset materials,
ionomer resin or highly neutralized acid polymer composition may
comprise inner core layer 330 or inner core layer 440 in particular
embodiments. For example, Surlyn.RTM., HPF 1000, HPF 2000, HPF
AD1027, HPF AD1035, HPF AD1040 and a mixture thereof, all produced
by E. I. Dupont de Nemours and Company may be used.
[0069] Inner core layer 330 or inner core layer 440 may be made by
a fabrication method such as hot-press molding or injection
molding. A diameter of inner core layer 330 or inner core layer 440
may be in a range of about 19 millimeters to about 37 millimeters,
or in a range of about 21 millimeters to about 35 millimeters, or
in a range of about 23 millimeters to about 32 millimeters. Inner
core layer 330 or inner core layer 440 may have a surface Shore D
hardness of 20 to 70.
[0070] In certain embodiments, if inner core layer 330 or inner
core layer 440 is made from a thermoplastic material, then outer
core layer 320 or outer core layer 430 may be made from a thermoset
material. In particular, outer core layer 320 or outer core layer
430 may comprise polyurethane elastomer, polyamide elastomer,
polyurea elastomer, diene-containing polymer (such as
polybutadiene), crosslinked metallocene catalyzed polyolefin,
silicone, and a mixture thereof. In particular embodiments, outer
core layer 320 or outer core layer 430 may comprise
polybutadiene.
[0071] In particular embodiments, a core layer may comprise
1,4-cis-polybutadiene in order to achieve superior resiliency
performance. Specifically, 1,4-cis-polybutadiene may be used as a
base material for outer core layer 320 or outer core layer 430, and
mixed with other ingredients. Generally, however,
1,4-cis-polybutadiene may be at least 50 parts by weight, based on
100 parts by weight of the composition of the outer core layer 320
or outer core layer 430.
[0072] Other additives, such as a crosslinking agent and a filler
with a greater specific gravity may further be added to the
composition of the outer core layer 320 or outer core layer 430.
Crosslinking agents may be selected from the group consisting of
zinc diacrylate, magnesium acrylate, zinc methacrylate, and
magnesium methacrylate. In particular embodiments, zinc acrylate
may be used in order to achieve increased resilience.
[0073] To increase specific gravity, a suitable filler may be added
in the rubber composition of the core layer. The filler may be zinc
oxide, barium sulfate, calcium carbonate, and magnesium carbonate.
Other fillers, such as a metal powder with a greater specific
gravity may also be used, such as tungsten. By means of adjusting
the amount of filler, the specific gravity of outer core layer 320
or outer core layer 430 may be controlled.
[0074] Finally, outer core layer 320 or outer core layer 430 may
have a surface Shore D hardness of 30 to 75.
[0075] Alternatively, inner core layer 330 or inner core layer 440
may comprise the aforementioned thermoset material while outer core
layer 320 or outer core layer 430 may comprise the thermoplastic
material, or any combination thereof.
[0076] In embodiments where the core construction is multilayered,
the C.O.R. of the inner core layer (such as inner core layer 330 in
FIG. 3 and inner core layer 440 in FIG. 4) at forty (40) meters per
second may be from about 0.79 to about 0.92, and may be higher than
that of the golf ball as a whole. Also, the C.O.R. of the golf ball
at forty (40) meters per second may be at least about 0.77.
[0077] After the final cover layer of the golf ball has been
molded, the golf ball may undergo various conventional finishing
processes such as buffing, stamping and painting. The finished golf
ball may have a compression deformation of 2 to 4 millimeters under
a load of 10 to 130 kilograms.
[0078] In particular embodiments, any of the various measured
properties may be present in a golf ball according to this
disclosure in any combination thereof. For example, a multi-part
golf ball according to this disclosure may exhibit the following
properties: (1) the golf ball has a compression deformation of from
about 2 to about 4 millimeters under a load of 10 to 130 kilograms;
(2) the inner core layer has a coefficient of restitution at 40
meters per second from about 0.79 to about 0.92, the coefficient of
restitution of the inner core being higher than that of the golf
ball; (3) the outer cover layer has a Shore D hardness from about
20 to about 75; and (4) the outer cover layer has a flexural
modulus of from about 1 kpsi to about 150 kpsi.
EXAMPLES
[0079] Two golf balls in accordance with the present disclosure
were fabricated as described below, and their scuff resistance was
compared to several comparative examples.
[0080] For each golf ball, the core was made from a material
selected from Table 1, and the cover layer was made from a material
selected from Table 2. The amount of the materials listed in Tables
1 and 2 is shown in parts by weight (pbw) or percentages by
weight.
TABLE-US-00001 TABLE 1 Core Materials Rubber compound: A B TAIPOL
.TM. BR0150* 100 100 Zinc diacrylate 28 25 Zinc oxide 5 5 Barium
sulfate 16 18 Peroxide 1 1
[0081] TAIPOL.TM. BR0150 is the trade name of a rubber produced by
Taiwan Synthetic Rubber Corp.
TABLE-US-00002 TABLE 2 Cover Materials C D E F G H I PTMEG (pbw)
100 100 100 100 BG (pbw) 15 15 15 15 TMPME 10% 10% 0 10% (weight %
to total components) DCP (weight 0.2% 0.5% 0 0 % to total
components) MDI (pbw) 87.8 87.8 55.0 87.8 (NCO index) 1.01 1.01
1.01 1.01 Texin .RTM. 245 100 Elastollan .RTM. 100 1195A Surlyn
.RTM. 8940 50 Surlyn .RTM. 9910 50
[0082] "PTMEG" is polytetramethylene ether glycol, having a number
average molecular weight of 2,000, and is commercially available
from Invista, under the trade name of Terathane.RTM. 2000. "BG" is
1,4-butanediol, commercially available from BASF and other
suppliers. "TMPME" is trimethylolpropane monoallylether,
commercially available from Perstorp Specialty Chemicals AB. "DCP"
is dicumyl peroxide, commercially available from LaPorte Chemicals
Ltd. Finally, "MDI" is diphenylmethane diisocyanate, commercially
available from Huntsman, under the trade name of Suprasec.RTM.
1100.
[0083] Cover materials C, D, E and F were formed by mixing PTMEG,
BG, TMPME, DCP and MDI in the proportions shown. Specifically,
these materials were prepared by mixing the components in a high
agitated stir for 1 minute, starting at a temperature of about 70
degrees Celsius, followed by a 10-hour post curing process at a
temperature of about 100 degrees Celsius. The post cured
polyurethane elastomers are ground into small chips.
[0084] Cover materials G, H and I are conventional golf ball cover
materials. Texin.RTM. 245 is trade name of thermoplastic
polyurethane resin by Bayer MaterialScience AG. Elastollan.RTM.
1195A is trade name of thermoplastic polyurethane resin by BASF.
Surlyn.RTM. 8940 and Surlyn.RTM. 9910 are trade names of ionomeric
resin by E. I. DuPont de Nemours and Company.
[0085] From the above core materials and cover materials, seven
golf balls were manufactured as shown in Table 3. Generally, the
golf balls were manufactured using conventional injection molding
processes known in the art of golf ball manufacturing.
[0086] In each case, the core had a diameter of 39.3 mm, the total
golf ball diameter was 42.7 mm, and the golf ball's total weight
was 45.4 grams.
TABLE-US-00003 TABLE 3 Golf Ball Scuff Resistance Examples
Comparative examples 1 2 3 4 5 6 7 Core--Rubber A A A A A A B Cover
Resin C D E F G H I Hardness, Shore D 53 53 53 53 53 53 69 Scuff
resistance Rating 2 1 3 4 3 3 4
[0087] A scuff resistance test was conducted in the following
manner: a Nike Victory Red forged standard sand wedge (loft:
54.degree.; bounce: 12.degree.; shaft: True Temper Dynamic Gold
shaft; flex: S) is fixed to a swing robot manufactured by Miyamae
Co., Ltd. and then swung at the head speed of about 32 m/s. The
club face was oriented for a square hit. The forward/backward tee
position was adjusted so that the tee was four inches behind the
point in the downswing where the club was vertical. The height of
the tee and the toe-heel position of the club relative to the tee
were adjusted in order that the center of the impact mark was about
3/4 of an inch above the sole and was centered toe to heel across
the face. Three samples of each ball were tested. Each ball was hit
three times.
[0088] Other methods may also be used to determine the scuff
resistance, such as the methods described in the commonly assigned
copending application titled "Golf Ball Wear Indicator", U.S.
Patent and Trademark Office Ser. No. 12/691,282, filed Jan. 21,
2010 in the name of Brad Tutmark.
[0089] After the above described scuff resistance testing, each
golf ball cover was visually observed and rated according to the
following scale: a golf ball cover was rated "1" when little or no
damage was visible, only groove markings or dents; a golf ball
cover was rated "2` when small cuts and/or ripples in the cover
were apparent; a golf ball cover was rated "3` when moderate
amounts of cover material were lifted from the ball's surface, but
the cover material was still attached to the ball; and finally a
golf ball cover was rated "4" when cover material was removed or
barely attached to the golf ball.
[0090] Shore D hardness values of the core and cover layer were
measured on the spherical surface of the layer to be measured by
using a Shore D hardness tester.
[0091] As shown in Table 3, golf ball examples 1 and 2 made from
compositions including a crosslinked thermoplastic polyurethane
elastomer having crosslinks located in the hard segments, where the
crosslinks are the reaction product of unsaturated bonds located in
the hard segments as catalyzed by a free radical initiator,
provides superior scuff resistance.
[0092] While various embodiments of the invention have been
described, the description is intended to be exemplary, rather than
limiting and it will be apparent to those of ordinary skill in the
art that many more embodiments and implementations are possible
that are within the scope of the invention. Accordingly, the
invention is not to be restricted except in light of the attached
claims and their equivalents. Also, various modifications and
changes may be made within the scope of the attached claims.
* * * * *