U.S. patent application number 11/552939 was filed with the patent office on 2007-03-08 for golf balls having sound-altered layers and methods of manufacture.
This patent application is currently assigned to TAYLOR MADE GOLF COMPANY, INC.. Invention is credited to Hyun Jin Kim, Eric Loper, Dean A. Snell.
Application Number | 20070054754 11/552939 |
Document ID | / |
Family ID | 32711221 |
Filed Date | 2007-03-08 |
United States Patent
Application |
20070054754 |
Kind Code |
A1 |
Kim; Hyun Jin ; et
al. |
March 8, 2007 |
GOLF BALLS HAVING SOUND-ALTERED LAYERS AND METHODS OF
MANUFACTURE
Abstract
Golf ball covers incorporate base material compositions
including a sound-altering material for selectively enhancing or
dampening the acoustic output of a golf ball when it is struck. A
ratio in the composition by weight of base material to
sound-altering material ranges between 99.9:0.1 and 92:8. The
invention allows for the altering of the sound of the golf ball
while retaining the mechanical properties of the golf ball
cover.
Inventors: |
Kim; Hyun Jin; (Carlsbad,
CA) ; Snell; Dean A.; (Carlsbad, CA) ; Loper;
Eric; (Carlsbad, CA) |
Correspondence
Address: |
SHEPPARD, MULLIN, RICHTER & HAMPTON LLP
333 SOUTH HOPE STREET
48TH FLOOR
LOS ANGELES
CA
90071-1448
US
|
Assignee: |
TAYLOR MADE GOLF COMPANY,
INC.
5545 Fermi Court
Carlsbad
CA
92008
|
Family ID: |
32711221 |
Appl. No.: |
11/552939 |
Filed: |
October 25, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10339995 |
Jan 10, 2003 |
7163471 |
|
|
11552939 |
Oct 25, 2006 |
|
|
|
Current U.S.
Class: |
473/378 |
Current CPC
Class: |
A63B 37/0003 20130101;
A63B 37/12 20130101; A63B 37/0052 20130101; A63B 37/0054
20130101 |
Class at
Publication: |
473/378 |
International
Class: |
A63B 37/14 20060101
A63B037/14 |
Claims
1. A golf ball having a core and one or more cover layers encasing
the core, wherein at least one of the one or more cover layers
comprises a composition, the composition comprising: a base
material; and a sound-altering material having outer surfaces that
have been treated to promote adhesion; wherein the weight ratio in
the composition of the base material to the sound-altering material
is between 98:2 and about 95:5; and wherein the sound-altering
material is configured to alter the sound produced when the golf
ball is struck without substantially altering the golf ball's
hardness and compression.
2. The golf ball of claim 1, wherein the sound-altering material is
a sound-enhancing material configured to increase the sound output
produced when the golf ball is struck.
3. The golf ball of claim 2, wherein the sound-enhancing material
comprises metal stearate.
4. The golf ball of claim 3, wherein the sound-enhancing material
comprises zinc stearate or calcium stearate.
5-6. (canceled)
7. The golf ball of claim 1, wherein the sound-altering material is
a sound-dampening material configured to increase the sound output
produced when the golf ball is struck.
8. The golf ball of claim 7, wherein the sound-dampening material
comprises a carbonate or a sulfate.
9. The golf ball of claim 8, wherein the sulfate is barium
sulfate.
10. The golf ball of claim 7, wherein the sound-dampening material
comprises hollow glass beads.
11-15. (canceled)
16. The golf ball of claim 1, wherein the base material comprises a
non-ionomeric polymer, an ionomeric polymer, or mixtures
thereof.
17. The golf ball of claim 16, wherein the non-ionomeric polymer
comprises thermoplastic polyurethane, thermoset polyurethane,
polyamide, silicone material, thermoplastic elastomers,
syndiotactic 1,2-polybutadiene, ethylene-vinyl-acetate, styrenic
copolymers, styrenic terpolymers, polymers having functional
groups, or mixtures thereof.
18. The golf ball of claim 16, wherein the ionomeric polymer
comprises a copolymeric ionomer, a terpolymeric ionomer, or
mixtures thereof.
19. The golf ball of claim 16, wherein the base material further
comprises UV stabilizers, photostabilizers, antioxidants,
colorants, dispersants, mold releasing agents, processing aids,
fibers, fillers, or mixtures thereof.
20. The golf ball of claim 1, wherein the cover layers comprise an
outer cover layer, and the outer cover layer comprises the
composition.
21. The golf ball of claim 1, wherein the cover layers comprise an
inner cover layer, and the inner cover layer comprises the
composition.
22. The golf ball of claim 20, further comprising one or more
intermediate layers situated between the core and the cover
layers.
23. The golf ball of claim 20, wherein the core comprises an inner
core and one or more outer cores encasing the inner core.
24. The golf ball of claim 20, wherein the core comprises
liquid.
25. The golf ball of claim 20, farther comprising a layer of rubber
thread situated between the core and the cover layers of the golf
ball.
26. The golf ball of claim 1, further comprising a layer of rubber
thread situated between the core and the cover layers of the golf
ball, wherein the rubber thread comprises the composition.
27. The golf ball of claim 1, wherein an acoustic pulse difference
between the base material combined with the sound-altering material
and the base material has a value between 0.01 and 0.09
Pascals.
28. The golf ball of claim 1, wherein an acoustic pulse difference
between the base material with the sound-altering material and the
base material has a value greater than 0.05 Pascals.
29. A method for preparing a golf ball layer, comprising the steps
of: preparing a composition comprising a base material, and a
sound-altering material having outer surfaces that have been
treated to promote adhesion, wherein the weight ratio in the
composition of the base material to the sound-altering material is
between 98:2 and about 95:5; and forming the composition into a
golf ball layer positioned around a golf ball core, wherein the
sound-altering material is configured to alter the sound produced
when the golf ball is struck, without substantially altering the
golf ball's hardness and compression.
30. The method as defined in claim 29, wherein the step of forming
the composition into a layer comprises injection molding the
composition to form the layer.
31. The method as defined in claim 29, wherein the step of
preparing a composition comprises a step of dry-blending the
composition.
32. The method as defined in claim 29, wherein the step of
preparing a composition comprises a step of mixing the composition
using a mill, internal mixer or extruder.
33. The method as defined in claim 29, wherein the step of
preparing a composition comprises incorporating into the
composition a non-ionomeric polymer, an ionomeric polymer, or
mixtures thereof.
34. The method as defined in claim 29, wherein the step of
preparing a composition comprises: preparing a concentrate by
premixing the sound-altering material with the base material; and
introducing the concentrate into a mixture comprising the base
material.
35. The method as defined in claim 29, wherein the step of forming
the composition into a layer comprises: forming the composition
into half cups; positioning the half cups over the core such that
the core is covered by the half cups; and increasing thermal energy
to and pressure on the half cups such that the half cups are bonded
together to form the layer.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates to cover layers for golf balls
incorporating material compositions having relatively small amounts
of sound-altering materials mixed therein, such that sound produced
by the golf balls when struck is selectively altered, while the
mechanical characteristics of the covers remain substantially the
same. The present invention also relates to methods of manufacture
of golf ball covers incorporating these sound-altering
materials.
[0002] Golf balls generally include a core and at least one cover
layer surrounding the core. Balls can be classified as two-piece,
multi layer, or wound balls. Two-piece balls include a spherical
inner core and an outer cover layer. Multi-layer balls include a
core, a cover layer and one or more intermediate (or mantle)
layers. The intermediate layers themselves may include multiple
layers. Wound balls include a core, a rubber thread wound under
tension around the core to a desired diameter, and a cover layer,
typically of balata material or thermoset polyurethane.
[0003] Generally, two-piece balls provide good durability and ball
distance when hit, but they provide poor ball control, due to low
spin rate and poor "feel" (the overall sensation transmitted to the
golfer while hitting the ball). Wound balls having balata covers
generally have high spin rate, leading to good control, and good
feel, but they have short distance and poor durability in
comparison to two-piece balls. Multi-layer balls generally have
performance characteristics between those of two-piece and wound
balls. Multi-layer balls exhibit distance and durability inferior
to two-piece balls but superior to wound balata, and they exhibit
feel and spin rate inferior to wound balata and thermoset
polyurethane balls but superior to two-piece balls. Thermoset
polyurethane covers tend to have very good durability, but they
have not yet attained the preferred feeling of balata.
[0004] Material characteristics of the compositions used in the
core, cover, and any intermediate layers are important in
determining the performance of the resulting golf balls. In
particular, the composition of the cover layer is important in
determining the ball's durability, scuff resistance, speed, shear
resistance, spin rate, feel, and "click" (the sound made when a
golf club head strikes the ball). Various materials having
different physical properties are used to make cover layers to
create a ball having the most desirable performance possible. For
example, many modern cover layers are made using soft or hard
ionomer resins, elastomeric resins or blends of these. Ionomeric
resins used generally are ionic copolymers of an olefin and a metal
salt of an unsaturated carboxylic acid, or ionomer terpolymers
having a co-monomer within its structure. These resins vary in
resiliency, flexural modulus, and hardness. Examples of these
resins include those marketed under the name SURLYN manufactured by
E.I. DuPont de Nemours & Company of Wilmington, Del., and IOTEK
manufactured by ExxonMobil Corporation of Irving, Tex. Elastomeric
resins used in golf ball covers include a variety of thermoplastic
or thermoset elastomers available. Layers other than cover layers
also significantly affect performance of a ball. The composition of
an intermediate layer is important in determining the ball's spin
rate, speed, and durability. The composition and resulting
mechanical properties of the core are important in determining the
ball's coefficient of restitution (C.O.R.), which affects ball
speed and distance when hit. In addition to the performance factors
discussed above, processability also is considered when selecting a
formulation for a golf ball composition. Good processability allows
for ease of manufacture using a variety of methods known for making
golf ball layers, while poor processability can lead to avoidance
of use of particular materials, even when those materials provide
for good mechanical properties.
[0005] Various materials having different physical properties are
used to make ball layers to create a ball having the most desirable
performance possible. Each of the materials discussed above has
particular characteristics that can lead to ball properties when
used in a golf ball composition, either for making a ball cover,
intermediate layer, or core. However, one material generally cannot
optimize all of the important properties of a golf ball layer.
Properties such as feel, speed, spin rate, resilience and
durability all are important, but improvement of one of these
properties by use of a particular material often can lead to
worsening of another. For example, ideally, a golf ball cover
should have good feel and controllability, without sacrificing ball
speed, distance, or durability. Despite the broad use of
copolymeric ionomers in golf balls, their use alone in, for
example, a ball cover can be unsatisfactory. A cover providing good
durability, controllability, and feel would be difficult to make
using only a copolymeric ionomer resin having a high flexural
modulus, because the resulting cover, while having good distance
and durability, also will have poor feel and low spin rate, leading
to reduced controllability of the ball. Also, the use of particular
elastomeric resins alone can lead to compositions having
unsatisfactory properties, such as poor durability and low ball
speed.
[0006] Therefore, to improve golf ball properties, the materials
discussed above can be blended to produce improved ball layers.
Prior compositions for golf balls have involved blending
high-modulus copolymeric ionomer with, for example, lower-modulus
copolymeric ionomer, terpolymeric ionomer, or elastomer. As
discussed above, ideally a golf ball cover should provide good feel
and controllability, without sacrificing the ball's distance and
durability. Therefore, a copolymeric ionomer having a high flexural
modulus often is combined in a cover composition with a
terpolymeric ionomer or an elastomer having a low flexural modulus.
The resulting intermediate-modulus blend possesses a good
combination of hardness, spin and durability.
[0007] However, even with blending of materials to improve ball
properties, use of the materials and blends discussed above has not
been completely satisfactory. Improving one characteristic can lead
to worsening of another. For example, blending an ionomer having a
high flexural modulus with an ionomer having a low flexural modulus
can lead to reduced resilience and durability compared to use of
the high-modulus ionomer alone. Also, the hardness of the
compositions that can be obtained from these blends are limited,
because durability and resilience get worse when hardness is
lowered by increasing terpolymeric content of these blends. In
general, it is difficult to make materials for use in, for example,
a golf ball cover layer that possess good feel, high speed, high
resilience, and good shear durability, and that are within a wide
range of hardness. Additional compositions meeting these criteria
are therefore needed.
[0008] In the past, in addition to the materials discussed above,
fillers have been added to base material compositions used in the
construction of golf balls. The filler generally has been added for
one of two purposes: 1) as a reinforcing agent; or 2) to adjust the
weight or density of a composition used in the formation of golf
ball cores, intermediate layers, or covers. The prior art is
replete with examples of both.
[0009] Descriptions of use of fillers reinforcing agents are found
in, for example, U.S. Pat. No. 3,883,145 to Cox et al. discloses
hydrated silica and barytes as reinforcing material. U.S. Pat. No.
5,759,676 to Cavallaro et al. discloses addition of glass fibers to
cover material as a reinforcing agent. This also is shown in
commonly-owned U.S. Pat. No. 6,012,991 to Kim et al., which
discloses glass fibers used as a reinforcing agent in a golf ball
intermediate layer composition. U.S. Pat. No. 4,836,552 to Puckett
discloses incorporation of glass bubbles into a ball material
composition to improve impact resistance.
[0010] Descriptions of fillers used to modify the density or weight
of a golf ball composition include U.S. Pat. No. 1,369,868 to
Worthington, which discloses the addition of wolframite to the core
of a golf ball. The addition of wolframite increases the overall
density of the core so that additional weight and, as a
consequence, additional ball flight are obtained. U.S. Pat. No.
3,671,477 to Nesbitt describes the addition of filler material to a
golf ball to control its weight without affecting its resilience.
The filler used in the Nesbitt patent preferably includes 20 to 40
parts per hundred by weight of hydrated silica. U.S. Pat. No.
4,863,167 to Matsuki discloses addition of heavy fillers such as
tungsten and lead to a mantle layer of a golf ball to push weight
away from the core of the golf ball. The Matsuki patent also
utilizes composition fillers such as zinc oxide, barium sulfate,
silica and zinc carbonate to maintain correct weight proportions
for the cover and core of the disclosed golf ball. U.S. Pat. No.
5,312,587 to Sullivan discloses the use of high ratio quantities of
metal stearates in compositions to act as fillers without reducing
C.O.R. values. The Sullivan patent states that such a use is
beneficial for reducing the material costs of golf ball
compositions. The Sullivan patent also points out that small
amounts of zinc stearate (i.e., from 0.01 to 1.0 pph) previously
had been used in the golf ball industry for facilitating the flow
of ionomer resins, and that the improvements of metal stearates as
a filler are only shown when the amounts used are greater than 10
pph of ionomer resin. U.S. Pat. No. 6,123,929 to Gonzenbach et al.
discloses use of glass fibers, barium sulfate and metal stearates
as a filler material for manipulating the density of the golf ball
compositions used.
[0011] The examples discussed above generally include large amount
of filler material, usually greater than 5 pph of the base
composition, and often greater than 20 pph of the base composition.
These large amounts are required for the filler material performs
its function, either as a reinforcing agent or as a
weight/density-modifying material. From another perspective, it is
seen that the fillers previously have been added with the explicit
purpose of altering the generally tested mechanical properties of a
golf ball (i.e., C.O.R., weight, shear resistance, and spin)
without regard to any change in non-mechanical properties that may
occur due to the addition of the filler material.
[0012] Of the physical characteristics of a golf ball, the two most
sought are high resilience and good feel. High resilience gives a
ball added distance, which is particularly desired by casual
golfers. However, high resilience balls (also known as distance
balls) generally are considered hard golf balls and do not provide
good feel for pitch shots and putting. A golf ball having what is
called good feel typically is softer than its distance counterpart.
This gives the golfer more confidence to control the distance of a
putt or a pitch shot, but it offers less distance for long shots.
The perceived feel of a ball is determined by more, however, than
its compression and resilience characteristics. When determining
the feel of a golf ball, most avid golfers, from casual to
professional, are sensitive to the sound of the ball when struck. A
louder, higher-pitched sound is associated with a hard, high
resilience ball, while a softer, lower-pitched sound is associated
with a soft ball.
[0013] Testing of sound characteristics when struck has been
performed on golf balls. A particular family of patents discloses
frequencies of specific golf balls materials. These patents include
U.S. Pat. Nos. 5,971,870, 6,425,833, 6,142,866 and 6,152,835,
collectively assigned to Spalding Sports Worldwide, Inc. These
patents discloses a golf ball made from a material, such that the
golf ball has a primary minimum value in a frequency range of 3100
Hz or less. An explanation follows of what causes the audible sound
emitted from a golf ball when it is struck by a golf club and how
that sound is measured.
[0014] A golf ball, when it is struck, is contracted along a
primary diameter from the point tangent to where the golf ball was
struck. The golf ball has a fixed circumference, and any
contraction along the primary diameter causes a secondary diameter,
perpendicular to the primary diameter, to elongate as it
compensates for the narrowing of the primary diameter. Though this
happens in three dimensions, it can be thought of as horizontal
line X and vertical line Y, wherein X is synonymous with the
primary diameter and Y is synonymous with the secondary diameter.
The sum of their lengths remains equal; thus, an extension of one
necessitates a narrowing of the other, and vice versa. The
resiliency of the material causes the now-narrowed primary diameter
to expand back to and beyond its original length, while the
secondary diameter contracts to a length less than its original
length. The deformation of the golf ball diameters between
extension and contraction defines an oscillation (or pressure
pulse) that vibrates against air molecules. The vibration of the
air molecules is, in effect, the sound that we hear. The
contraction and extension of the golf ball is greatest along the
primary diameter and second diameters, because the primary diameter
is tangent to where the ball was struck. Because the primary and
secondary diameters oscillate more than other diameters of the golf
ball, the oscillation of the primary and secondary diameters define
the first acoustic mode which generates the most audible pressure
pulse. In the above-mentioned Spalding patents, this first acoustic
mode is called the primary value. The purpose of the inventions
disclosed in these patents is to produce a cover material having a
specific first acoustic mode having a frequency lower than 3100
kilohertz. however, in these patents, no effort was made to alter
either the decibel level or the frequency of the materials
produced.
[0015] Because a golf ball is solid, it cannot oscillate only
between two diameters or even two perpendicular planes. The solid
nature of the ball causes additional oscillations on planes that
are not coplanar with either the primary or secondary diameters.
Additional acoustic modes are caused by oscillations along other
diameters and include a great number of diameters. The second
acoustic mode includes elongation and contraction along three
diameters that intersect each other, the third acoustic mode
includes four diameters and so on. While theoretically there is no
limit to the number of acoustics modes, as spheres have an infinite
number of diameters, there is a limit to which we can pick out the
nodes with sound listening equipment. As the energy input
increases, higher order acoustic modes are excited. Generally, the
oscillations of these acoustic modes are small and their
frequencies are too high for the human ear to detect. For that
reason, it is generally the first, second, and sometimes third,
acoustic modes that are the most important acoustic modes. Also,
altering the frequency of the first acoustic mode will alter the
frequency of the remaining acoustic modes. Thus, lowering the
frequency of the first acoustic mode will lower the frequency of
the second and third acoustic modes, so that the overall sound
detected has a lower frequency.
[0016] The frequency of the golf ball is most important to altering
the perceived sound of the ball when struck when putting or making
short shots, such as pitching onto a green. Thhis is because a golf
ball struck with a longer club, such a driver, does not oscillate
as much as the head of the club which struck the ball. For that
reason, when a golfer strikes a golf ball with a driver, the driver
primarily provides thesound that is heard, and little is given to
the golfer in the way of soft or hard impressions relating to the
ball. Conversely, when a golfer strikes a ball with a putter, the
mass of the putter and ease of the stroke cause little oscillation
in the putter and therefore the "click" of the golf ball is
heard.
[0017] Another way to measure sound with respect to golf ball
constructions and materials is to primarily rely on decibel levels.
The decibel level includes all of the acoustic modes and is a
function of how much sound is emitted from the material when it is
struck. Decibels are converted from Pascals, which indicate the
magnitude and duration of the pressure pulse associated with the
sound. A ball emitting a smaller pressure pulse (lower Pascal
output) will give the impression of a softer feeling. This is true
even if measurements of the C.O.R. indicate that the material
properties of the golf ball have remained essentially the same.
[0018] Golf balls having a high pitch or high acoustic output are
viewed as too hard, while balls having a low pitch or low acoustic
output are perceived as a ball having a short flight distance. This
perception holds true regardless of the actual mechanical
properties of the golf ball in question. In view of this problem
and the ones stated above, it is apparent that a method to adjust
the frequency or Pascal output for golf balls, while retaining the
C.O.R. of the golf balls, as well as the golf balls including such
features, is needed. This will allow the manufacturer to adjust the
sound of the golf ball so that it is tuned to the satisfaction of a
golfer, while retaining the mechanical properties (i.e., C.O.R.,
resilience) of the ball. The present invention fulfills this need
and provides further related advantages.
SUMMARY OF THE INVENTION
[0019] The present invention relates to new and improved golf balls
that overcome the above-referenced problems. An object of the
invention is to form a cover or cover layers for a golf ball
comprising a base composition and a sound-altering material. Golf
balls within the scope of the invention can be solid, wound,
two-piece, or multi-layered golf balls.
[0020] More specifically, the present invention resides in a golf
ball having a core and one or more cover layers encasing the core,
in which at least one of the cover layers incorporates a
composition comprising a base material, and a sound-altering
material, in which the ratio by weight of base material to
sound-altering material ranges between 99.9:0.1 and about 92:8,.
The sound-altering material is configured to alter the sound
produced when the golf ball is struck, without substantially
altering other properties of the golf ball. The sound-altering
material can be either a sound-enhancing material configured to
increase the sound output produced when the golf ball is struck, or
a sound-dampening material configured to decrease the sound output
produced when the golf ball is struck. Preferred sound-enhancing
materials include metal stearates, such as zinc stearate or calcium
stearate, or solid glass beads, optionally having a surface
treatment. Preferred sound-dampening materials include carbonates
and sulfates, such as barium sulfate, and hollow glass beads,
optionally having a surface treatment.
[0021] In preferred embodiments of the compositions, the ratio by
weight of base material to sound-altering material ranges between
99.9:0.1 and about 92:8, more preferably between 99.9:0.1 and about
95:5, more preferably between 99:1 and about 95:5, and most
preferably between 98:2 and about 95:5. The base material
preferably incorporates non-ionomeric or ionomeric polymers, or
mixtures of these. Preferred nonionomeric polymers include
thermoplastic polyurethane, thermoset polyurethane, polyamide,
silicone material, thermoplastic elastomers, syndiotactic
1,2-polybutadiene, ethylene-vinyl-acetate, styrenic copolymers,
styrenic terpolymers, polymers having functional groups, or
mixtures of these. Preferred ionomeric materials include
copolymeric ionomer, terpolymeric ionomer, or mixtures of these.
The base material also can include UV stabilizers,
photostabilizers, antioxidants, colorants, dispersants, mold
releasing agents, processing aids, fibers, fillers, or mixtures of
these.
[0022] Golf balls within the scope of the present invention can
incorporate multiple cover layers, in which the outer or one of the
inner cover layers incorporates the composition. Golf balls within
the scope of the present invention can have a variety of
constructions, including: one or more intermediate layers situated
between the core and the cover layer; an inner core and one or more
outer cores encasing the inner core; a core incorporating liquid;
or, a layer of rubber thread situated between the core and the
cover layer. If the ball incorporates a layer of rubber thread, the
rubber thread also can incorporate the composition of the present
invention.
[0023] Preferably, the acoustic pulse difference between the base
material combined with the sound-altering material and the base
material alone has a value between 0.01 and 0.09 Pascals, or
greater than 0.05 Pascals.
[0024] Related methods for preparing a golf ball layer, incorporate
preparing a composition comprising a base material; and a
sound-altering material, in which the ratio by weight of base
material to sound-altering material ranges between 99.9:0.1 and
92:8, and forming the composition into a golf ball layer positioned
around a golf ball core. The composition can be formed into a layer
using injection molding, dry-blending, or mixing using a mill,
internal mixer or extruder. The sound-altering material can be
premixed with the base material to form a concentrate of
sound-altering material, and mixing the concentrate into a mixture
incorporating the base material. The composition can be formed into
a layer by, for example, forming the composition into half cups,
positioning the half cups over the core so that the core is covered
by the half cups, and increasing thermal energy to and pressure on
the half cups so that the half cups are bonded together to form a
layer.
[0025] Other features and advantages of the present invention
should become apparent from the following detailed description of
the preferred embodiments.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0026] The present invention is embodied in golf balls having cover
layers incorporating compositions incorporating a base composition
and a sound-altering material. The present invention also is
embodied in golf ball cover layers made from the above-specified
composition, and it additionally resides in methods of manufacture
of balls incorporating these cover layers. The invention also
resides in balls incorporating layers of wound rubber thread that
incorporate a sound-altering material. The combination of the base
composition and sound-altering material allows for formation of
golf ball cover layers that are provide the performance of hard
covers, including high C.O.R. and shear resistance, while offering
the sound and perception of soft covers. The composition also
allows for providing golf balls having essentially identical
physical parameters with a different sound upon being struck with a
putter.
[0027] It has been found that the addition of relatively small
amounts of sound-altering material may be added to the cover
material of the golf ball to selectively alter the sound of the
golf ball while retaining the remaining physical mechanics of the
cover material. For example, with the addition of a sound-altering
material to a golf ball having a hard cover, a golfer would be
provided with a golf ball cover offering a high resilience for
longer drives but the perception of a soft ball on the greens.
Another example includes the addition of a sound-altering material
to a golf ball having a soft cover so that the golfer is provided
with a ball having low resilience for good control but the
perception of a hard ball for long shots.
[0028] Preferred embodiments of the present invention suitable for
use in make golf ball covers include compositions comprising a base
material or resin and a sound-altering material. Preferably, the
ratio by weight of base material to sound-altering material ranges
between 99.9:0.1 and about 92:8, more preferably between 99.9:0.1
and about 95:5, even more preferably between 99:1 and about 95:5,
and most preferably between 98:2 and about 95:5.
[0029] The base material generally may include any material that is
conventionally used in the forming of golf ball covers. These
materials can typically be grouped into ionomeric materials and
non-ionomeric materials and blends of these. Non-ionomeric
materials generally include balata, trans-polyisoprene (synthetic
balata), silicones, thermoplastic polyurethanes, thermoset
polyurethanes, polyamides, 1,2-polybutadiene, thermoplastic
elastomers, polymers with functional groups and polyester
elastomers. Ionomeric materials generally include copolymeric
ionomers and terpolymeric ionomers.
[0030] The base material used within the scope of the present
invention also can include, in suitable amounts, one or more
additional ingredients or additives for achieving specific
functions when generally employed in golf balls and ball
compositions. Suitable ingredients include UV stabilizers,
photostabilizers, antioxidants, colorants, dispersants, mold
releasing agents, processing aids, and inorganic fillers. The
compositions can incorporate, for example, metallic fillers, such
as titanium dioxide, calcium carbonate, zinc sulfide or zinc oxide.
Additional fillers, such as those mentioned in the above cited
patents, can be chosen to impart additional density to the
compositions, such as zinc oxide, tungsten or any other metallic
powder having density higher than that of the base polymeric resin.
An example of these is silica-reinforcing filler This filler
preferably is selected from finely divided, heat-stable minerals,
such as fumed and precipitated forms of silica, silica aerogels and
titanium dioxide having a specific surface area of at least about
10 m.sup.2/gram. Any organic, inorganic, or metallic fibers, either
continuous or non-continuous, also can be in the compositions.
[0031] A. Non-Ionomeric Materials
[0032] 1. Polyurethane
[0033] Polyurethane can be obtained from the reaction product of
polyol and diisocynate. For example, in one method, polyol having
macromolecule and organic polyisocyanate react to produce urethane
prepolymer, and thus urethane prepolymer reacts with a chain
extender, such as polyol, diisocyanate, diamines, or mixtures of
these. Polyurethanes that are particularly suitable for making
compositions of the present invention are curable polyurethanes
including urethane prepolymers. The chemical components for making
curable thermoplastic polyurethanes are discussed below.
[0034] a. Isocyanates
[0035] Suitable isocyanates include: trimethylene diisocyanate,
tetramethylene diisocyanate, pentamethylene diisocyanate,
hexamethylene diisocyanate, ethylene diisocyanate, diethylidene
diisocyanate, propylene diisocyanate, butylenes diisocyanate,
bitolylene diisocyanate, tolidine isocyanate, isophorone
diisocyanate, dimeryl diisocyanate, dodecane-1,12-diisocyanate,
1,10-decamethylene diisocyanate, cyclohexylene-1,2-diisocyanate,
1,10-decamethylene diisocyanate, 1-chlorobenzene-2,4-diisocyanate,
furfurylidene diisocyanate, 2,4,4-trimethyl hexamethylene
diisocyanate, 2,2,4-trimethyl hexamethylene diisocyanate,
dodecamethylene diisocyanate, 1,3-cyclopentane diisocyanate,
1,3-cyclohexane diisocyanate, 1,3-cyclobutane diisocyanate,
1,4-cyclohexane diisocyanate, 4,4'-methylenebis(cyclohexyl
isocyanate), 4,4'-methylenebis(phenyl isocyanate),
1-methyl-2,4-cyclohexane diisocyanate, 1-methyl-2,6-cyclohexane
diisocyanate, 1,3-bis(isocyanato-methyl)cyclohexane,
1,6-diisocyanato-2,2,4,4-tetra-methylhexane,
1,6-diisocyanato-2,4,4-tetra-trimethylhexane,
trans-cyclohexane-1,4-diisocyanate,
3-isocyanato-methyl-3,5,5-trimethylcyclo-hexyl isocyanate,
1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane,
cyclo-hexyl isocyanate, dicyclohexyl-methane 4,4'-diisocyanate,
1,4-bis(isocyanatomethyl) cyclohexane, m-phenylene diisocyanate,
m-xylylene diisocyanate, m-tetramethylxylylene diisocyanate,
p-phenylene diisocyanate, p, p'-biphenyl diisocyanate,
3,3'-dimethyl-4,4'-biphenylene diisocyanate,
3,3'-dimethoxy-4,4'-biphenylene diisocyanate,
3,3'-diphenyl-4,4'-biphenylene diisocyanate, 4,4'-biphenylene
diisocyanate, 3,3'-dichloro-4,4'-biphenylene diisocyanate,
1,5-naphthalene diisocyanate, 4-chloro-1,3-phenylene diisocyanate,
1,5-tetrahydronaphthalene diisocyanate, metaxylene diisocyanate,
2,4-toluene diisocyanate, 2,4'-diphenylmethane diisocyanate,
2,4-chlorophenylene diisocyanate, 4,4'-diphenylmethane
diisocyanate, p,p'-diphenylmethane diisocyanate, 2,4-tolylene
diisocyanate, 2,6-tolylene diisocyanate,
2,2-diphenylpropane-4,4'-diisocyanate, 4,4'-toluidine diisocyanate,
dianidine diisocyanate, 4,4'-diphenyl ether diisocyanate,
1,3-xylylene diisocyanate, 1,4-naphthylene diisocyanate,
azobenzene-4,4'-diisocyanate, diphenyl sulfone-4,4'-diisocyanate,
triphenylmethane 4,4',4''-triisocyanate, isocyanatoethyl
methacrylate,
3-isopropenyl-.alpha.,.alpha.-lydimethylbenzyl-isocyana
dichlorohexamethylene diisocyanate,
.omega.,.omega.'-diisocyanato-1,4-diethylbenzene, polymethylene
polyphenylene polyisocyanate, and isocyanurate modified compounds,
carbodiimide modified compounds and biuret modified compounds of
the above polyisocyanates. These may be used either alone or in
combination. Also suitable are triisocyanates such as biuret of
hexamethylene diisocyanate and triphenylmethane triisocyanate, and
polyisocyanates such as polymeric diphenylmethane diisocyanate.
[0036] b. Polyols
[0037] Suitable polyols include polyester polyol, polyether polyol,
polycaprolactone polyol, polycarbonate polyol and polybutadiene
polyol, or mixtures of these.
[0038] (i) Polyester Polyols
[0039] Polyester polyols are prepared by condensation or
step-growth polymerization. The main diacids for polyester polyols
are adipic acid and the three isomeric phthalic acids. Adipic acid
is used for applications requiring flexibility, whereas phthalic
anhydride is used for those requiring rigidity. poly(ethylene
adipate) (PEA), poly(diethylene adipate) (PDA), poly(propylene
adipate) (PPA), poly(tetramethylene adipate) (PBA),
poly(hexamethylene adipate) (PHA), poly(neopentylene adipate)
(PNA), polyol composed of 3-methyl-1,5-pentanediol and adipic acid,
random copolymer of PEA and PDA, random copolymer of PEA and PPA,
random copolymer of PEA and PBA, random copolymer of PHA and PNA,
caprolactone polyol obtained by the ring-opening polymerization of
.epsilon.-caprolactone, and polyol obtained by opening the ring of
.beta.-methyl-.delta.-valerolactone with ethylene glycol, can be
used either alone or in a combination thereof Preferably, those
polyols have molecular weights of at least 500. Additionally, the
polyester polyol may be composed of a copolymer of at least one of
the following acids and at least one of the following glycols.
[0040] Suitable acids include: Terephthalic acid, isophthalic acid,
phthalic anhydride, oxalic acid, malonic acid, succinic acid,
pentanedioic acid, hexanedioic acid, octanedioic acid, nonanedioic
acid, adipic acid, azelaic acid, sebacic acid, dodecanedioic acid,
dimer acid (a mixture), .rho.-hydroxybenzoate, trimellitic
anhydride, .epsilon.-caprolactone, and
.beta.-methyl-.delta.-valerolactone.
[0041] Suitable glycols include: Ethylene glycol, propylene glycol,
butylene glycol, pentylene glycol, 1,4-butanediol, 1,5-pentanediol,
1,6-hexanediol, neopentylene glycol, polyethylene glycol,
polytetramethylene glycol, 1,4-cyclohexane dimethanol,
pentaerythritol, and 3-methyl-1,5-pentanediol.
[0042] (ii) Polyether Polyols
[0043] Polyether polyols are prepared by the ring-opening addition
polymerization of an alkylene oxide (e.g. ethylene oxide and
propylene oxide) with an initiator of a polyhydric alcohol (e.g.
diethylene glycol), which is an active hydride. Specifically,
polypropylene glycol (PPG), polyethylene glycol (PEG) or propylene
oxide-ethylene oxide copolymer can be obtained. Polytetramethylene
ether glycol (PTMG) is prepared by the ring-opening polymerization
of tetrahydrofuran, produced by dehydration of 1,4-butanediol or
hydrogenation of filran. Tetrahydrofuran can form a copolymer with
other alkylene oxide. Specifically, tetrahydrofuran-propylene oxide
copolymer or tetrahydrofuran-ethylene oxide copolymer can be
formed. The above polyols preferably have molecular weight of at
least 500 and may be used either alone or in a combination.
[0044] (iii) Polycarbonate Polyols
[0045] Polycarbonate polyol is obtained by the condensation of a
known polyol (polyhydric alcohol) with phosgene, chloroformic acid
ester, dialkyl carbonate or diallyl carbonate. It varies in
molecular weight. Particularly preferred polycarbonate polyol
contains a polyol component using 1,6-hexanediol, 1,4-butanediol,
1,3-butanediol, neopentylglycol or 1,5-pentanediol. They have
molecular weight of at least 500 and can be used either alone or in
a combination.
[0046] (iv) Polybutadiene Polyol
[0047] Polybutadiene polyol includes the following. The liquid
diene polymer containing hydroxyl groups has a molecular weight of
at least 600 and an average number of functional groups at least
1.7, and they may be composed of diene polymer or diene copolymer,
having at least 4 carbon atoms, or a copolymer of such diene
monomer with addition polymerizable .alpha.-olefin monomer, having
at least 2 carbon atoms. Specific examples include butadiene
homopolymer, isoprene homopolymer, butadiene-styrene copolymer,
butadiene-isoprene copolymer, butadiene-acrylonitrile copolymer,
butadiene-2-ethyl hexyl acrylate copolymer, and
butadiene-n-octadecyl acrylate copolymer. These liquid diene
polymers can be obtained, for example, by heating a conjugated
diene monomer with the presence of hydrogen peroxide in a liquid
reactant.
[0048] c. Plasticizers
[0049] Suitable plasticizers include: dioctyl phthalate (DOP),
dibutyl phthalate (DBP), dioctyl adipate (DOA), triethylene glycol
dibenzoate, tricresyl phosphate, dioctyl phthalate, aliphatic ester
of pentaerythritol, dioctyl sebacate, diisooctyl azelate.
[0050] d. Extenders
[0051] Suitable extenders and/or curatives used in the present
invention may be any material generally used for hardening urethane
prepolymer to produce polyurethane elastomer. Non-limiting examples
include polyols, polyamine compounds, and mixtures of these. Polyol
extenders may be primary, secondary, or tertiary polyols, Specific
examples of monomers of these polyols include the following:
trimethylolpropane (TMP), ethylene glycol, 1,3-propanediol,
1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, propylene glycol,
dipropylene glycol, 1,2-butanediol, 1,3-butanediol, 2,3-butanediol,
1,2-pentanediol, 2,3-pentanediol, 2,5-hexanediol, 2,4-hexanediol,
2-ethyl-1,3-hexanediol, cyclohexanediol, and
2-ethyl-2-(hydroxymethyl)-1,3-propanediol. Diamines also can be
added to urethane prepolymer to function as chain extenders.
Suitable diamines include: tetramethylenediamine,
pentamethylenediamine, hexamethylenediamine,
p,p'-methylenedianiline, p-phenylenediamine and others. Aromatic
diamines have a tendency to provide a stiffer (higher Mooney
viscosity) product than aliphatic or cycloaliphatic diamines.
Suitable polyamines that can be used as chain extenders include,
any of a primary amine, a secondary amine and a tertiary. amine,
such as diamine, triamine and tetramine. Examples of these include:
an aliphatic amine such as hexamethylenediamine; an alicyclic amine
such as 3,3'-dimethyl-4,4'-diaminodicyclohexyl methane; an aromatic
amine such as 4,4'-methylene bis-2-chloroaniline, 2,2',
3,3'-tetrachloro-4,4'-diaminophenyl methane or
4,4'-diaminodiphenyl; and 2,4,6-tris(dimethylaminomethyl) phenol.
These extenders may be used either alone or in combination.
Urethane prepolymer may be hardened by mixing it with chain
extender using conventional methods, or by varying a mix ratio of
the extender to the urethane prepolymer under proper processing
conditions, such as processing temperature and processing time.
[0052] 2. Polyamides
[0053] Suitable polyamides for use as an additional material in
compositions within the scope of the present invention also include
resins obtained by: (1) polycondensation of (a) a dicarboxylic
acid, such as oxalic acid, adipic acid, sebacic acid, terephthalic
acid, isophthalic acid or 1,4-cyclohexylidicarboxylic acid, with
(b) a diamine, such as ethylenediamine, tetramethylenediamine,
pentamethylenediamine, hexamethylene-diamine or
decamethylenediamine, 1,4-cyclohexyldiamine or m-xylylenediamine;
(2) a ring-opening polymerization of cyclic lactam, such as
.epsilon.-caprolactam or .omega.-laurolactam; (3) polycondensation
of an aminocarboxylic acid, such as 6-aminocaproic acid,
9-aminononaoic acid, 11-aminoudecanoic acid or 12-aminododecanoic
acid; or, (4) copolymerization of a cyclic lactam with a
dicarboxylic acid and a diamine. Specific examples of suitable
polyamides include Nylon 6, Nylon 66, Nylon 610, Nylon 11, Nylon
12, copolymerized Nylon, Nylon MXD6, and Nylon 46.
[0054] 3. 1,2-polybutadiene
[0055] Syndiotactic 1,2-polybutadiene having crystallinity suitable
for use in compositions within the scope of the present invention
are polymerized from 1,2.sub.13 addition of butadiene. These
include syndiotactic 1,2-polybutadiene having crystallinity and
having greater than about 70% of 1,2.sub.13 bonds, more preferably
greater than about 80%, and most preferably greater than about 90%.
These syndiotactic 1,2-polybutadienes have crystallinity between
about 5% and about 50%, more preferably about 10% and about 40%,
and most preferably between about 15% and about 30%. These
syndiotactic 1,2-polybutadienes have a mean molecular weight
between about 10,000 and about 350,000, more preferably between
about 50,000 and about 300,000, more preferably between about
80,000 and about 200,000, and most preferably between about 10,000
and about 150,000. An example of a suitable syndiotactic
1,2-polybutadiene for use in the scope of the present invention
polybutadiene is sold under the trade name RB810, RB820, and RB830
by JSR Corporation of Tokyo, Japan. These have more than 90% of 1,2
bonds, mean molecular weight of approximately 120,000, and
crystallinity between about 15% and 30%.
[0056] 4. Silicones
[0057] Silicone materials also are well suited for blending into
compositions within the scope of the present invention. These can
be monomers, oligomers, prepolymers, or polymers, with or without
additional reinforcing filler. One type of silicone material that
is suitable can incorporate at least 1 alkenyl group having at
least 2 carbon atoms in their molecules. Examples of these alkenyl
groups include, but are not limited to, vinyl, allyl, butenyl,
pentenyl, hexenyl and decenyl. The alkenyl functionality can be
located at any location of the silicone structure, including one or
both terminals of the structure. The remaining (i.e., non-alkenyl)
silicon-bonded organic groups in this component are independently
selected from hydrocarbon or halogenated hydrocarbon groups that
contain no aliphatic unsaturation. Non-limiting examples of these
include: alkyl groups, such as methyl, ethyl, propyl, butyl, pentyl
and hexyl; cycloalkyl groups, such as cyclohexyl and cycloheptyl;
aryl groups such as phenyl, tolyl and xylyl; aralkyl groups, such
as benzyl and phenethyl; and halogenated alkyl groups, such as
3,3,3-trifluoropropyl and chloromethyl. Another type of silicone
material suitable for use in the present invention is one having
hydrocarbon groups that lack aliphatic unsaturation. Specific
examples of suitable silicones for use in making compositions of
the present invention include the following:
trimethylsiloxy-endblocked dimethylsiloxane-methylhexenylsiloxane
copolymers; dimethylhexenlylsiloxy-endblocked
dimethylsiloxane-methylhexenylsiloxane copolymers;
trimethylsiloxy-endblocked dimethyl siloxane-methylvinylsiloxane
copolymers; trimethylsiloxy-endblocked
methylphenylsiloxane-dimethylsiloxane-methylvinylsiloxane
copolymers; dimethylvinylsiloxy-endblocked dimethylpolysiloxanes;
dimethylvinylsiloxy-endblocked dimethylsiloxane-methylvinylsiloxane
copolymers; dimethylvinylsiloxy-endblocked
methylphenylpolysiloxanes; dimethylvinylsiloxy-endblocked
methylphenyl siloxane-dimethylsiloxane-methylvinyl siloxane
copolymers; and, the copolymers listed above, in which at least one
end group is dimethylhydroxysiloxy. Commercially available
silicones suitable for use in compositions within the scope of the
present invention include Silastic by Dow Corning Corp. of Midland,
Mich., Blensil by GE Silicones of Waterford, N.Y., and Elastosil by
Wacker Silicones of Adrian, Mich.
[0058] 5. Thermoplastic Elastomers
[0059] Thermoplastic elastomers for use within the scope of the
present invention include polyester elastomers marketed under the
name SKYPEL by SK Chemicals of South Korea or HYTREL from DuPont.
Also of use are triblock copolymers marketed under the name HG-252
by Kuraray Corporation of Kurashiki, Japan. These triblock
copolymers have at least one polymer block comprising an aromatic
vinyl compound and at least one polymer block comprising a
conjugated diene compound, and a hydroxyl group at a block
copolymer. Also preferred are polyamide elastomers and in
particular polyetheramide elastomers. Of these, suitable
thermoplastic polyetheramides are chosen from among the family of
Pebax, which are available from Elf-Atochem Company. The materials
listed above all can provide for particular enhancements to ball
layers prepared within the scope of the present invention.
[0060] 6. Polymers Having Functional Groups
[0061] Among thermoplastic elastomers with functional or polar
groups that are contemplated are thermoplastic elastomers with
functional groups, such as carboxylic acid, maleic anhydride,
glycidyl, norbonene, and hydroxyl group. Examples are maleic
anhydride functionalized triblock copolymer consisting of
polystyrene end blocks and poly(ethylene/butylene); maleic
anhydride modified ethylene-vinyl acetate copolymer;
ethylene-isobutyl acrylate-methacrylic acid terpolymer;
ethylene-ethyl acrylate-maleic anhydride terpolymer and
ethylene-ethyl acrylate-maleic anhydride terpolymer; bromonated
styrene-isobutylene copolymers; Lotader resins having glycidyl or
maleic anhydride functional groups; and mixtures of the above
resins.
[0062] Examples of suitable additional polymers for use in the
present invention include, but are not limited to, the following:
thermoset elastomer, synthetic rubber, thermoplastic vulcanizate,
polycarbonate, polyesters, polyvinyl alcohols,
acrylonitrile-butadiene-styrene copolymers, polyarylate,
polyacrylate, polyphenyl ether, modified-polyphenyl ether,
high-impact polystyrene, diallyl phthalate polymer, metallocene
catalyzed polymers, acrylonitrile--styrene-butadiene (ABS),
styrene-acrylonitrile (SAN) (including olefin-modified SAN and
acrilonitrile styrene acrylonitrile), styrene-maleic anhydryde
(S/MA) polymer, styrenic copolymer, functionalized styrenic
copolymer, functionalized styrenic terpolymer, styrenic terpolymer,
cellulose polymer, liquid crystal polymer LCP),
ethylene-propylene-diene terpolymer (EPDM), ethylene-vinyl acetate
copolymers (EVA), ethylene-propylene copolymer, ethylene vinyl
acetate, and polyurea or any metallocene-catalyzed polymers of
these species. Particularly suitable plasticizers for use in the
compositions within the scope of the present invention include:
polyethylene-terephthalate, polybutyleneterephthalate,
polytrimethylene-terephthalate, ethylene-carbon monoxide copolymer,
polyvinyl-diene fluorides, polyphenylenesulfide,
polypropyleneoxide, polyphenyloxide, polypropylene, functionalized
polypropylene, polyethylene, ethylene-octene copolymer,
ethylene-methyl acrylate, ethylene-butyl acrylate, polycarbonate,
polysiloxane, functionalized polysiloxane, copolymeric ionomer,
terpolymeric ionomer, polyetherester elastomer, polyesterester
elastomer, polyetheramide elastomer, propylene-butadiene copolymer,
modified copolymer of ethylene and propylene, styrenic copolymer
(including styrenic block copolymer and randomly distributed
styrenic copolymer, such as styrene-isobutylene copolymer and
styrene-butadiene copolymer), partially or fully hydrogenated
styrene-butadiene-styrene block copolymers such as
styrene-(ethylene-propylene)-styrene or
styrene-(ethylene-butylene)-styrene block copolymers, partially or
fully hydrogenated styrene-butadiene-styrene block copolymers with
functional group, polymers based on ethylene-propylene-(diene),
polymers based on functionalized ethylene-propylene-(diene),
dynamically vulcanized
polypropylene/ethylene-propylene-diene-copolymer, thermoplastic
vulcanizates based on ethylene-propylene-(diene), natural rubber,
styrene-butadiene rubber, nitrile rubber, chloroprene rubber,
fluorocarbon rubber, butyl rubber, acrylic rubber, silicone rubber,
chlorosulfonated polyethylene, polyisobutylene, alfin rubber,
polyester rubber, epichlorphydrin rubber, chlorinated
isobutylene-isoprene rubber, nitrile-isobutylene rubber,
1,2-polybutadiene, 1,4-polybutadiene, cis-polyisoprene,
trans-polyisoprene, and polybutylene-octene.
[0063] B. Ionomeric Materials
[0064] As mentioned above, ionomeric polymers often are found in
covers and intermediate layers of golf balls. These ionomers also
are well suited for blending into compositions within the scope of
the present invention. Suitable ionomeric polymers (i.e.,
copolymer- or terpolymer-type ionomers) include
.alpha.-olefin/unsaturated carboxylic acid copolymer-type ionomeric
or terpolymer-type ionomeric resins that can be described as
copolymer E/X/Y, where E represents ethylene, X represents a
softening comonomer such as acrylate or methacrylate, and Y is
acrylic or methacrylic acid. The acid moiety of Y is neutralized to
form an ionomer by a cation such as lithium, sodium, potassium,
magnesium, calcium, barium, lead, tin, zinc or aluminum. Also, a
combination of such cations is used for the neutralization.
Examples of suitable ionomeric resins include those marketed under
the name SURLYN manufactured by E.I. DuPont de Nemours &
Company of Wilmington, Del., and IOTEK manufactured by Exxon Mobil
Corporation of Irving, Tex.
[0065] 1. Copolymeric Ionomers
[0066] Copolymeric ionomers are obtained by neutralizing at least
portion of carboxylic groups in a copolymer of an .alpha.-olefin
and an .alpha.,.beta.-unsaturated carboxylic acid having 3 to 8
carbon atoms, with a metal ion. Examples of suitable
.alpha.-olefins include ethylene, propylene, 1-butene, and
1-hexene. Examples of suitable unsaturated carboxylic acids include
acrylic, methacrylic, ethacrylic, alphachloroacrylic, crotonic,
maleic, fumaric, and itaconic acid. Copolymeric ionomers include
ionomers having varied acid contents and degrees of acid
neutralization, neutralized by monovalent or bivalent cations
discussed above.
[0067] 2. Terpolymeric Ionomers
[0068] Terpolymeric ionomers are obtained by neutralizing at least
portion of carboxylic groups in a terpolymer of an .alpha.-olefin,
and an .alpha.,.beta.-unsaturated carboxylic acid having 3 to 8
carbon atoms and an .alpha.,.beta.-unsaturated carboxylate having 2
to 22 carbon atoms with metal ion. Examples of suitable
.alpha.-olefins include ethylene, propylene, 1-butene, and
1-hexene. Examples of suitable unsaturated carboxylic acids include
acrylic, methacrylic, ethacrylic, alphachloroacrylic, crotonic,
maleic, fumaric, and itaconic acid. Terpolymeric ionomers include
ionomers having varied acid contents and degrees of acid
neutralization, neutralized by monovalent or bivalent cations
discussed above.
[0069] The sound-altering material of the present invention may be
selected from any number of materials, including those that have
traditionally been used as weight fillers or as processing aids.
The preferred materials include carbonates, sulfates, glass beads
and metal stearates. In particular, carbonates sulfates, and hollow
glass beads generally function to dampen the sound of a cover
material. In contrast, metal stearates and solid glass beads tend
to enhance the sound of the cover material. The preferred
sound-altering materials include: zinc stearate supplied by
AkroChem of Akron, Ohio; soda-lime glass spheres with a coupling
agent, or borosilicate glass spheres with a coupling agent,
supplied by Potter Industries, Inc. of Vally Forge, Pa.; and,
Hubberbrite 3 (barium sulfate having a median particle size 3.2
microns) and Hubberbrite 10 (barium sulfate having a median
particle size of 9.0 microns) supplied by JM Huber Corp., Edison,
N.J. When glass beads are used as the sound-altering material, any
conventional surface treatment may be added to the beads for
promoting adhesion between the surface of the glass beads and the
base material of the composition. Silanes are particularly useful
in these surface treatements.
[0070] The base composition and sound-altering material can be
mixed together to form the composition of the present invention,
with or without melting them. Dry blending equipment, such as a
tumbler mixer, V-blender, or ribbon blender, can be used to mix the
compositions. The sound-altering material can be mixed together
with the base composition or constituents of the base composition.
The sound-altering material also can be added after addition of any
of the additional materials discussed above. Materials can be added
to the composition using a mill, internal mixer, extruder or
combinations of these, with or without application of thermal
energy to produce melting. In another method of manufacture of
these compositions, the sound-altering material can be premixed
with the base composition to produce a concentrate having a high
concentration of sound-altering material. Then, this concentrate
can be introduced into a composition of base composition urethane
and additional materials using dry blending, melt mixing or
molding. The additional materials also can be added to a color
concentrate, which is then added to the composition to impart a
white color to golf ball.
[0071] Conventionally, golf ball cover and intermediate layers are
positioned over a core or other internal layer using one of three
methods: casting, injection molding, or compression molding.
Injection molding generally involves using a mold having one or
more sets of two hemispherical mold sections that mate to form a
spherical cavity during the molding process. The pairs of mold
sections are configured to define a spherical cavity in their
interior when mated. When used to mold an outer cover layer for a
golf ball, the mold sections can be configured so that the inner
surfaces that mate to form the spherical cavity include protrusions
configured to form dimples on the outer surface of the molded cover
layer. The mold sections are connected to openings, or gates,
evenly distributed near or around the parting line, or point of
intersection, of the mold sections through which the material to be
molded flows into the cavity. The gates are connected to a runner
and a sprue that serve to channel the molding material through the
gates. When used to mold a layer onto an existing structure, such
as a ball core, the mold includes a number of support pins disposed
throughout the mold sections. The support pins are configured to be
retractable, moving into and out of the cavity perpendicular to the
spherical cavity surface. The support pins maintain the position of
the core while the molten material flows through the gates into the
cavity between the core and the mold sections. The mold itself may
be a cold mold or a heated mold. In the case of a heated mold,
thermal energy is applied to the material in the mold so that a
chemical reaction may take place in the material.
[0072] In contrast to injection molding, which generally is used to
prepare layers from thermoplastic materials, casting often is used
to prepare layers from thermoset material (i.e., materials that
cure irreversibly). In a casting process, the thermoset material is
added directly to the mold sections immediately after it is
created. Then, the material is allowed to partially cure to a
gelatinous state, so that it will support the weight of a core.
Once cured to this state, the core is positioned in one of the mold
sections, and the two mold sections are then mated. The material
then cures to completion, forming a layer around the core.
[0073] Compression molding of a ball layer typically requires the
initial step of making half shells by injection molding the layer
material into a cold injection mold. The half shells then are
positioned in a compression mold around a ball core, whereupon heat
and pressure are used to mold the half shells into a complete layer
over the core. Compression molding also can be used as a curing
step after injection molding. In such a process, an outer layer of
thermally curable material is injection molded around a core in a
cold mold. After the material solidifies, the ball is removed and
placed into a mold, in which heat and pressure are applied to the
ball to induce curing in the outer layer by compression
molding.
[0074] A preferred method within the scope of the present invention
involves injection molding a core, intermediate layer, or cover of
the composition. In yet another preferred method, an intermediate
layer or a cover of the composition can be prepared by injection
molding half-shells. The half shells are then positioned around a
core and compression molded. The heat and pressure melt the
composition to seal the two half shells together to form a complete
layer. Depending on the materials used for the base composition,
additional thermal energy may be added to induce crosslinking.
[0075] In addition to the above, a preferred aspect of the method
involves preparing the cover layer using injection molding and
forming dimples on the surface of the cover layer. Alternately, the
cover layer can be formed using injection molding without dimples,
after which the cover layer is compression molded to form
dimples.
EXAMPLES
[0076] A series of trials were conducted on golf balls prepared
within the scope of the present invention, as well as on golf balls
currently marketed for control, including the Taylor Made Distance
Plus, the Maxfli Noodle, the Ben Hogan Apex Tour, and the Titleist
Pro V1. Also tested for control was a golf ball designated ITS5-18A
The balls prepared for the trials incorporated either
sound-dampening or sound-enhancing materials Three types of
sound-dampening and five types of sound-enhancing balls were
prepared, respectively designated SD1 to SD 3 and SE1 to SE5. To
prepare these balls, cover compositions were compounded using twin
screw extrusion and then injection-molded around conventional cores
or core/mantle sections to form covers of the golf balls.
[0077] The acoustic tests were performed by dropping the test golf
balls from a height of eight feet onto a marble block. A microphone
placed near the block recorded the sound produced by each golf ball
as it struck the block. The sound waves were converted into
electrical impulses, which then were converted into Pascals. This
procedure measure the entire sound produced and does not
distinguish between particular frequencies or mode. The
measurement, in effect, primarily is a function of decibel level of
the sound produced. A lower Pascal output effectuates a softer
sound, which gives the perception of a softer feel. A greater
Pascal output creates a louder sound, which gives the perception of
a harder feel. Tests were run for each of the two types of
sound-altering materials used. The balls were tested for cover
hardness, ball compression, driver and 8-Iron speed and spin rate,
and acoustic output. The compositions, physical properties and
sound-related characteristics for the sound-dampening balls are
shown below in Tables 1 and 2. The compositions, physical
properties and sound-related characteristics for the
sound-enhancing balls are shown below in Tables 3 and 4.
TABLE-US-00001 TABLE 1 SD1 SD2 SD3 Distance Plus Core Size 1.58''
1.58'' 1.58'' 1.58'' Core Compression 75 75 75 75 Core C.O.R 0.803
0.803 0.803 0.803 Mantle Hardness (Shore D) n/a n/a n/a n/a Cover
Hardness (Shore D).sup.1 62 62 63 61 Type of Dampening Filler.sup.2
Huberbrite-3* Huberbrite-3* Huberbrite-12* None (control) Sound
Dampening Filler Content in 2 6 2 n/a Cover Composition (pph) PGA
Ball Compression 86 87 85 84 USGA Driver Speed (mph) 162.3 162.1
162 162 USGA Driver Spin Rate (rpm) 2940 2990 2890 2980 8-Iron
Speed (mph) 110.3 110.4 110.4 110.1 8-Iron Spin Rate (rpm) 7110
7300 6770 6900 Acoustic Output (Pascals) .68 .72 .71 .77
.sup.1Cover Composition: Ionomer Blend .sup.2Sound Dampening
Filler: same type of filler having a different average particle
sizes: Hubberbrite 3 is barium sulfate having a median particle
size 3.2 microns; Hubberbrite 10 is barium sulfate having a median
particle size of 9.0 microns *Barium Sulfate
[0078] The data in Table 1 illustrate that the addition of small
amounts of barium sulfate to a cover composition will dampen the
sound output of the golf ball, while retaining the mechanical
properties of the original composition. As can be seen by the spin
rates and speeds of the tested golf balls, similar measurements are
seen with respect to the control ball (Distance Plus). This
indicates that while the ball will have the flight characteristics
of the Distance Plus, it will sound differently to the golfer when
that golfer is putting or hitting short shots. A way to illustrate
this effect more dramatically is to compare the combined feel
(i.e., the sum of the cover hardness and ball compression values,
which relates to perceived feel of the ball by a golfer) of the
test balls and golf balls currently on the market. TABLE-US-00002
TABLE 2 Distance SD1 SD2 SD3 Plus Noodle Apex Tour Pro V1 Combined
Feel 148 149 148 145 135 136 132 Acoustic .68 .72 .71 .77 .71 .71
.69 Output (Pascals)
[0079] The fact that the Maxfli Noodle, Ben Hogan Apex Tour and
Titleist Pro V1 balls all are considered "soft balls" is validated
by their relatively low values for combined feel and their soft
sound when struck. On the other hand, the test balls within the
scope of the present invention, SD1 to SD3, generally exhibit the
higher combined feel values of a hard, distance ball, but they
possess the low Pascal measurements generally associated with the
marketed soft golf balls tested. TABLE-US-00003 TABLE 3 SE1 SE2 SE3
SE4 SE5 ITS5-18A Core Size 1.48'' 1.48'' 1.48'' 1.48'' 1.48''
1.48'' Core Compression 55 55 55 55 55 55 Core C.O.R 0.795 0.795
0.795 0.795 0.795 0.795 Mantle Hardness (Shore D).sup.2 57 57 57 57
57 57 Cover Hardness (Shore D).sup.1 51 49 50 49 50 51 Type of
Sound Enhancing Filler Zinc Zinc Stearate 3000A CP-02** 3000A
CP-02** 3000E CP-02** None Sterarate (control) Sound Enhancing
Filler.sup.3 Content 3 5 3 5 5 n/a in Cover Composition (pph) PGA
Ball Compression 70 71 70 71 70 70 USGA Driver Speed (mph) 159.3
159.3 159.7 159.1 159.2 159 USGA Driver Spin Rate (rpm) 3230 3300
3340 3370 3250 3300 8-Iron Speed (mph) 109.6 109.7 109.6 109.9
109.6 109.2 8-Iron Spin Rate (rpm) 7280 7510 7340 7540 7290 7440
Acoustic Output (Pascals) .67 .64 .65 .65 .64 .61 .sup.1Cover
Composition: Thermoplastic elastomer Blend .sup.2Mantle
Composition: Ionomer Blend .sup.3Sound Enhancing Filler: Metal
Stearate and inorganic filler having different surface treatment
**glass beads
[0080] The data in Table 3 confirm that sound output may be
increased by addition of small amounts of zinc stearate or glass
beads, while again retaining the mechanical properties of the
original composition. There are negligible speed and spin rate
differences between the test balls and ITS5-18A, the control ball.
This indicates that the golf ball will have the same flight
characteristics of the control ball, while sounding harder while
putting or making relatively short shots. Again, this effect is
shown more dramatically by comparing the combined feel values of
the test balls within the scope of the present invention to golf
balls currently on the market. TABLE-US-00004 TABLE 4 ITS5- SE1 SE2
SE3 SE4 SE5 18A Pro V1 Apex Tour Noodle Combined Feel 121 120 120
120 120 121 145 135 136 Acoustic Output .67 .64 .65 .65 .64 .61 .69
.71 .71 (Pascals)
[0081] The data in Table 4 indicate that a ball having a very soft
cover can be made to have the acoustic output of a similar ball on
the market. In this case, the SE1, though having a much softer
cover and lower combined feel than the PRO V1, has an acoustic
output of 0.67 Pascals, which is very similar to the PRO V1
acoustical output of 0.69 Pascals. In general, balls SE1 to SE5 all
exhibit far lower combined feel values than the marketed balls, but
possess similar acoustic output. This results in the balls
performing as softer, more controllable balls, while having the
sound characteristics of harder balls.
[0082] These test results show that sound altering of a material
composition is possible without sacrificing the mechanical
characteristics of the composition. The sound output may
selectively be increased or decreased depending on the needs of the
golfer. Also, the addition of the sound-altering material causes no
processing difficulties making it an economical method for
producing golf balls having desirable properties.
[0083] Although the invention has been disclosed in detail with
reference only to the preferred embodiments, those skilled in the
art will appreciate that additional compositions amd methods can be
made without departing from the scope of the invention.
Accordingly, the invention is defined only by the claims set forth
below.
* * * * *