U.S. patent application number 11/685932 was filed with the patent office on 2007-07-05 for gold ball having a foamed layer created by infrared radiation.
Invention is credited to Matthew F. Hogge, Derek A. Ladd, Michael J. Sullivan.
Application Number | 20070155542 11/685932 |
Document ID | / |
Family ID | 36575054 |
Filed Date | 2007-07-05 |
United States Patent
Application |
20070155542 |
Kind Code |
A1 |
Sullivan; Michael J. ; et
al. |
July 5, 2007 |
GOLD BALL HAVING A FOAMED LAYER CREATED BY INFRARED RADIATION
Abstract
This invention is directed to a golf ball having a foamed layer
and the method for creating the foamed layer by the heating of
blowing agents with infrared radiation. Either physical blowing
agents can be de-volatized, or chemical blowing agents (both
organic and inorganic) may be decomposed wherein the blowing agents
are generated within the layer. The resultant layer is less dense
than the core layer beneath it.
Inventors: |
Sullivan; Michael J.;
(Barrington, RI) ; Hogge; Matthew F.; (Plymouth,
MA) ; Ladd; Derek A.; (Acushnet, MA) |
Correspondence
Address: |
ACUSHNET COMPANY
333 BRIDGE STREET
P. O. BOX 965
FAIRHAVEN
MA
02719
US
|
Family ID: |
36575054 |
Appl. No.: |
11/685932 |
Filed: |
March 14, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10341572 |
Jan 13, 2003 |
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11685932 |
Mar 14, 2007 |
|
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10141481 |
May 8, 2002 |
6855070 |
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10341572 |
Jan 13, 2003 |
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Current U.S.
Class: |
473/371 |
Current CPC
Class: |
B29C 35/0805 20130101;
A63B 37/0064 20130101; B29K 2105/243 20130101; B29C 2035/0822
20130101; B29L 2031/54 20130101; A63B 37/0074 20130101; A63B
37/0063 20130101; A63B 37/0075 20130101; B29C 35/0266 20130101 |
Class at
Publication: |
473/371 |
International
Class: |
A63B 37/04 20060101
A63B037/04 |
Claims
1. A multilayer golf ball comprising a core, an intermediate layer,
and a cover, wherein the intermediate layer comprises an expandable
polymeric composition containing a blowing agent therein, wherein
the expandable polymeric composition expands from 5% to 200% of its
pre-expand thickness when the expandable polymeric composition is
heated with infrared radiation at a specific temperature and
predetermined time.
2. The golf ball of claim 1, wherein the blowing agent is a
thermally decomposable inorganic chemical blowing agent selected
from the group consisting of ammonium carbonate and carbonates of
alkali metals.
3. The golf ball of claim 1, wherein the blowing agent is a
thermally decomposable organic blowing agent selected from the
group consisting of azo and diazo compounds, nitroso compounds,
sulfonylhydrazides, azides of organic acids and their analogs,
triazines, tri-and tetrazole derivatives, sulfonyl semicarbazides,
urea derivatives, guanidine derivatives, or esters such as
alkoxyboroxines.
4. The golf ball of claim 1, wherein the blowing agent is a
de-volatizable physical blowing agent selected from a volatile
liquid group consisting of freons, halogenated hydrocarbons, water,
aliphatic hydrocarbons, gases, or solid adsorbents that liberate
gas as a result of desorption of gas.
5. The golf ball of claim 4, wherein the solid adsorbents are
selected from a group consisting of activated carbon, calcium
carbonate, diatomaceous earth, and silicates saturated with carbon
dioxide.
6. The golf ball of claim 1, wherein the expandable polymeric
composition comprises a plurality of thermally expandable
polyspheres encapsulating an expandable blowing agent in the form
of a solvent, wherein when heated by infrared radiation the solvent
expands into a gas that is released into the layer.
7. The golf ball of claim 1, wherein the intermediate layer has a
density that is lower than the density of the core.
8. The golf ball of claim 11, wherein the intermediate layer
includes a blowing agent that liberates a gas as a result of a
chemical interaction between components selected from a group
consisting of mixtures of acids and metals, mixtures of organic
acids and inorganic carbonates, mixtures of nitrites and ammonium
salts and the hydrolytic decomposition of urea.
9. The golf ball of claim 1, wherein the intermediate layer is a
water vapor barrier layer.
10. A method of forming a foamed intermediate layer in a
multi-layer golf ball, the method comprising: providing a core;
encapsulating the core with a intermediate layer comprising an
expandable polymeric composition containing a blowing agent;
heating the intermediate layer with infrared radiation at a
specific temperature for a pre-determined time, wherein the
expandable polymeric composition expands from 5% to 200% to create
a foamed layer; and enclosing the intermediate layer with a
cover.
11. The method of claim 10, wherein the blowing agent is a
thermally decomposable inorganic chemical blowing agent selected
from the group consisting of ammonium carbonate and carbonates of
alkali metals.
12. The method of claim 10, wherein the blowing agent is a
thermally decomposable organic blowing agent selected from the
group consisting of azo and diazo compounds, nitroso compounds,
sulfonylhydrazides, azides of organic acids and their analogs,
triazines, tri-and tetrazole derivatives, sulfonyl semicarbazides,
urea derivatives, guanidine derivatives, or esters such as
alkoxyboroxines.
13. The method of claim 10, wherein the blowing agent is a
devolatizable physical blowing agent selected from a volatile
liquid group consisting of freons, halogenated hydrocarbons, water,
aliphatic hydrocarbons, gases, or solid adsorbents that liberate
gas as a result of desorption of gas.
14. The method of claim 13, wherein the solid adsorbents are
selected from a group consisting of activated carbon, calcium
carbonate, diatomaceous earth, and silicates saturated with carbon
dioxide.
15. The method of claim 10, wherein the expandable polymeric
composition comprises a plurality of thermally expandable
polyspheres encapsulating an expandable blowing agent in the form
of a solvent which expands into a gas that is released into the
layer.
16. The method of claim 10, wherein the intermediate layer has a
density that is lower than the density of the core.
17. The method of claim 10, wherein the cover layer has a density
lower than the density of the intermediate layer.
18. The method of claim 10, wherein the intermediate layer includes
a blowing agent that liberates a gas as a result of a chemical
interaction between components selected from a group consisting of
mixtures of acids and metals, mixtures of organic acids and
inorganic carbonates, mixtures of nitrites and ammonium salts and
the hydrolytic decomposition of urea.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is a continuation-in-part of co-pending
U.S. application Ser. No. 10/341,572, which was a divisional of
co-pending U.S. application Ser. No. 10/141,481 which was filed May
8, 2002, and now is U.S. Pat. No. 6,855,070, and is incorporated
herein in its entirety by express reference thereto.
FIELD OF THE INVENTION
[0002] This invention relates to the utilization of infrared
radiation to form a foamed layer, cross-linking an intermediate
layer, and post-curing a cover layer.
BACKGROUND OF THE INVENTION
[0003] Generally, golf balls have been classified as wound balls or
solid balls. Wound balls are generally constructed from a liquid or
solid center surrounded by tensioned elastomeric material. Wound
balls are generally thought of as performance golf balls and have a
good resiliency, spin characteristics and feel when struck by a
golf club. However, wound balls are generally difficult to
manufacture when compared to solid golf balls.
[0004] Solid golf balls were initially, two piece balls, i.e.,
comprising a core and a cover. More recently developed solid balls
are comprised of a core, one or more mantle layers and one or more
covers, in order to improve the playing characteristics of the
ball.
[0005] In the manufacture of solid golf ball cores, all cores have
a slight cure gradient. This is a normal result of the cure
conditions, which usually heat from the outside in. The current
practice is generally to form a core with the most uniformity for
the given construction. If it is desired to create cure gradients
having large differences, or to use materials that are not typical
to the art, generally, it has been necessary to use high molding
temperatures for long periods of time (i.e. 175.degree. C. for 30
minutes).
[0006] The prior art is comprised of a variety of golf balls that
have been designed to provide particular playing characteristics.
These characteristics are generally the initial velocity and spin
of the golf ball, which can be optimized for various types of
players. For instance, certain players prefer a ball that has a
high spin rate in order to control and stop the golf ball. Other
players prefer a ball that has a low spin rate and high resiliency
to maximize distance. Generally, a golf ball having a hard core and
a soft cover will have a high spin rate. Conversely, a golf ball
having a hard cover and a soft core will have a low spin rate. Golf
balls having a hard core and a hard cover generally have very high
resiliency for distance, but are hard feeling and difficult to
control around the greens. Various prior art references have been
directed to adding a mantle layer or second cover layer to improve
the playability of solid golf balls.
[0007] As indicated above, the spin rate of golf balls is the end
result of many variables, softness of the cover in relationship to
the inner core or an inner mantle layer is but one of these
variables. Spin rate is an important characteristic of golf balls
for both skilled and recreational golfers. High spin rate allows
the more skilled players, such as PGA professionals and low
handicapped players, to maximize control of the golf ball. A high
spin rate golf ball is advantageous for an approach shot to the
green. The ability to produce and control backspin to stop the ball
on the green and side spin to draw or fade the ball substantially
improves the player's control over the ball. Hence, the more
skilled players generally prefer a golf ball that exhibits high
spin rate.
[0008] On the other hand, recreational players who cannot
intentionally control the spin of the ball generally do not prefer
a high spin rate golf ball. For these players, slicing and hooking
are the more immediate obstacles. When a club head strikes a ball,
an unintentional side spin is often imparted to the ball, which
sends the ball off its intended course. The side spin reduces the
player's control over the ball, as well as the distance the ball
will travel. A golf ball that spins less tends not to drift
off-line erratically if the shot is not hit squarely off the club
face. The low spin ball will not cure the hook or the slice, but
the lower spin will reduce the adverse effects of the side spin.
Hence, recreational players prefer a golf ball that exhibits low
spin rate.
[0009] The prior art teaches of having either a soft or a hard
intermediate (inner cover) layer formed about a core to achieve
particular performances, as seen above, from a golf ball. A means
of achieving these types of performance characteristics without the
use of any mantle layer may be attainable through the use of
gradient curing to create hardness gradients on the outer skin or
shell of the golf ball core.
[0010] U.S. Pat. Nos. 5,803,834, 5,733,206, 5,976,443, 6,113,831,
5,697,856, 4,650,193, 4,570,937, and 4,858,924 are examples of
creating gradients in the core of a golf ball.
SUMMARY OF THE INVENTION
[0011] The invention provides a method for forming in a multilayer
golf ball, an intermediate layer comprising an expandable polymeric
composition containing a blowing agent, wherein the expandable
polymeric composition expands from 5% to 200% of its pre-expand
thickness when the expandable polymeric composition is heated with
infrared radiation at a specific temperature and predetermined
time. The intermediate layer has a density less than the core.
[0012] In one embodiment, the blowing agent is a thermally
decomposable inorganic chemical blowing agent selected from the
group consisting of ammonium carbonate and carbonates of alkali
metals.
[0013] In yet another embodiment, the blowing agent is a thermally
decomposable organic blowing agent selected from the group
consisting of azo and diazo compounds, nitroso compounds,
sulfonylhydrazides, azides of organic acids and their analogs,
triazines, tri-and tetrazole derivatives, sulfonyl semicarbazides,
urea derivatives, guanidine derivatives, or esters such as
alkoxyboroxines.
[0014] One embodiment discloses a blowing agent that is a
de-volatizable physical blowing agent selected from a volatile
liquid group consisting of freons, halogenated hydrocarbons, water,
aliphatic hydrocarbons, gases, or solid adsorbents that liberate
gas as a result of desorption of gas. The solid adsorbents are
selected from a group consisting of activated carbon, calcium
carbonate, diatomaceous earth, and silicates saturated with carbon
dioxide.
[0015] An embodiment of the invention provides the expandable
polymeric composition to be comprised of a plurality of thermally
expandable polyspheres encapsulating an expandable blowing agent in
the form of a solvent, wherein when heated by infrared radiation
the solvent expands into a gas that is released into the layer.
[0016] The blowing agent of the present invention may liberate a
gas as a result of a chemical interaction between components
selected from a group consisting of mixtures of acids and metals,
mixtures of organic acids and inorganic carbonates, mixtures of
nitrites and ammonium salts and the hydrolytic decomposition of
urea.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0017] The method of the present invention includes creating
gradients upon a spherical object such as golf ball core and a
cover. The method of the invention would work equally as well with
one-piece balls as described in U.S. Pat. No. 6,162,135,
multi-layer core balls or a ball made with a laminated construction
as described in U.S. Pat. No. 6,056,842, which is incorporated by
reference herein in its entirety.
[0018] As previously stated, in the manufacture of golf balls, all
golf balls have a slight cure gradient that is created by the very
nature of the cure conditions, which is heating from the outside
in. The cure conditions are optimized to create the cure with the
most uniformity for the given construction. If cure gradients that
have large differences were desired or if materials that are not
typical of the art were desired, then they could be achieved with
high molding temperatures for long periods of time (i.e.
175.degree. C. for 30 minutes).
[0019] The present invention employs the method of Infrared
Radiation (IR) for forming a foamed layer in intermediate and cover
layers. The description herein will focus mainly upon the forming
of foamed layers, however, it is to be appreciated that IR
represents a potential alternative means of cross-linking any
portion of a ball, including a cover, a coating or any intermediate
layer.
[0020] The Electromagnetic Spectrum includes all types of
radiation: Gamma-rays, X-rays, Ultraviolets, visible light,
infrared light, microwaves and radio waves. All these rays and
waves in the Electromagnetic Spectrum are different only because
the length of their waves are different. Short wavelength radiation
is of the highest energy and can be very dangerous (X-rays and
Ultraviolets). Longer wavelength radiation, which includes IR, is
of lower energy and usually is harmless. IR radiation is a very
radiant form of heating. It heats objects and people directly,
without the need to heat up the air in between. The prefix "infra"
is Latin for below and refers to the wavelengths that are below the
red end of the visible spectrum. IR radiation is generally split
into three wavelengths: short-wave, medium-wave and long-wave. The
wavelengths can vary from 0.7 microns to about 100 microns. For
each of these types of infra-red heating, there is a wide choice of
emitter and wavelength. Selection of the correct type for a
particular application is usually critical. The type of wavelength
employed in the present invention is the medium-length wherein the
emitter operates at bright red heat. The absorption wavelengths of
C.dbd.C groups which include butadiene is about 6.07 microns. The
absorption range for most of the materials reported in this
invention fall between about 5 to 6.8 microns. The type of emitter
to provide IR in this range are well known by those in the field
and medium-wave panels can be easily retrofitted to existing hot
air or contra-flow ovens. The following U.S. Pat. Nos. 6,174,388,
6,024,813, 5,677,362, 5,672,393, and 5,665,192, which are
incorporated by reference herein in their entirety, describe
various methods of curing with IR (although not of a golf ball core
or cover).
[0021] Disclosed herein is a novel methodology in the use of
rubbers, curing agents and high temperature peroxides in normal
formulations, in such a way that they will not fully cure when
molded, but will more fully cure when exposed to infrared
radiation. Preferably, they will then be more fully cured only at
the first several mils on the surface of the golf ball core/air
interface. This results in a highly cross-linked surface and a soft
center. This may be completed in a short time span, i.e. 5 minutes
if by infrared radiation. The core having been molded, the
structural framework will stay intact. The outside core surface
will experience high (175-300.degree. C.) temperatures.
[0022] The following terms are used in this application. Shore D
and C Harnesses are measured by the ASTM method D-2240.
"Compression points" refer to the compression scale or the
compression scale based on the ATTI Engineering Compression Tester.
This scale, which is well known to those working in this field, is
used in determining the relative compression of a core or ball. The
compression is measured by applying a spring-loaded force to the
golf ball center, golf ball core or the golf ball to be examined,
with a manual instrument manufactured by the Atti Engineering
Company of Union City, N.J. This machine, equipped with a Federal
Dial Gauge, Model D81-C, employs a calibrated spring under a known
load. The sphere to be tested is forced a distance of 0.2 inch
against this spring. If the spring, in turn, compresses 0.2 inch,
the compression is rated at 100; it the spring compresses 0.1 inch,
the compression value is rated as 0. Thus more compressible, softer
materials will have a lower Atti gauge values than harder, less
compressible materials. Compression measured with this instrument
is also referred to as PGA compression.
[0023] As used herein, "COR" refers to Coefficient of Restitution,
which is obtained by dividing a ball's rebound velocity by its
initial (i.e. incoming) velocity. This test is performed by firing
the samples out of an air cannon at a vertical steel plate over a
range of test velocities (from 75 to 150 ft./sec). A golf ball
having a high COR dissipates a smaller fraction of its total energy
when colliding with the plate and rebounding therefrom than does a
ball with a lower COR. Unless otherwise noted, the COR values
reported herein are the values determined at an incoming velocity
of 125 ft./sec.
[0024] The term "about," as used herein in connection with one or
more numbers or numerical ranges, should be understood to refer to
all such numbers, including all numbers in a range.
[0025] As used herein, the term "pph" in connection with a batch
formulation refers to parts by weight of the constituent per
hundred parts of the base composition.
[0026] The present invention involves a method of creating in a
multi-layered golf ball an intermediate or cover layer that is less
dense than the layer beneath it. This is accomplished by the
infrared heating of the intermediate or cover layer comprising an
expandable polymeric composition containing a blowing agent that
upon exposure to infrared heating expands to create the less dense
layer.
[0027] An embodiment of the invention, employs a one piece core (up
to a diameter of about 1.65 inches) and an intermediate and cover
layer. Included in the intermediate layer is an expandable
polymeric composition containing a blowing agent. On exposure to
infrared radiation for a specific time and temperature, the
expandable polymeric composition expands the layer from about 5 to
200% of the pre-expand thickness. The foamed intermediate layer is
then less dense that the core beneath it. When a cover layer is
foamed in this manner, it is less dense than the layer beneath it.
As such, when the core has a Shore D hardness of greater than 50,
preferably greater than 60, the intermediate layer is softer than
the core by at least 3 Shore D points and preferably at least
5.
[0028] The core composition can be made from any suitable core
materials including thermoset polymers, such as natural rubber,
ethylene propylene rubber or epdiene monomer, polybutadiene (PBD),
polyisoprene, styrene-butadiene or styrene-propylene-diene rubber,
and thermoplastics such as ionomer resins, polyamides, polyesters,
or a thermoplastic elastomer. Suitable thermoplastic elastomers
include Pebax.RTM., which is believed to comprise polyether amide
copolymers, Hytrel.RTM., which is believed to comprise polyether
ester copolymers, thermoplastic urethane, and Kraton.RTM., which is
believed to comprise styrenic block copolymers elastomers. These
products are commercially available from Elf-Atochem, E.I. Du Pont
de Nemours and Company, various manufacturers, and Shell Chemical
Company, respectively. The core materials can also be formed from a
castable material. Suitable castable materials include those
comprising a urethane, polyurea, epoxy, silicone, IPN's, etc.
[0029] The polybutadiene rubber composition preferably includes
between about 2.2 parts and about 5 parts of a halogenated
organosulfur compound. The halogenated conventional materials for
such cores include core compositions having a base rubber, a
cross-linking agent, filler and a co-cross-linking agent. The base
rubber typically includes natural or synthetic rubbers. A preferred
base rubber is 1,4-polybutadiene having a cis-structure of at least
40%. Natural rubber, polyisoprene rubber and/or styrene-butadiene
rubber may be optionally added to the 1,4-polybutadiene. The
initiator included in the core composition can be any known
polymerization initiator that decomposes during the cure cycle. The
cross-linking agent includes a metal salt of an unsaturated fatty
acid such as a zinc salt or a magnesium salt of an unsaturated
fatty acid having 3 to 8 carbon atoms such as acrylic or
methacrylic acid. The filler typically includes materials such as
tungsten, zinc oxide, barium sulfate, silica, calcium carbonate,
zinc carbonate and the like. The polybutadiene rubber composition
preferably includes between about 2.2 parts and about 5 parts of a
halogenated organosulfur compound. The halogenated organosulfur
compound may include pentafluorothiophenol; 2-fluorothiophenol;
3-fluorothiophenol; 4-fluorothiophenol; 2,3-fluorothiophenol;
2,4-fluorothiophenol; 3,4-fluorothiophenol; 3,5-fluorothiophenol;
2,3,4-fluorothiophenol; 3,4,5-fluorothiophenol;
2,3,4,5-tetrafluorothiophenol; 2,3,5,6-tetrafluorothiophenol;
4-chlorotetrafluorothiophenol; pentachlorothiophenol;
2-chlorothiophenol; 3-chlorothiophenol; 4-chlorothiophenol;
2,3-chiorothiophenol; 2,4-chlorothiophenol; 3,4-chlorothiophenol;
3,5-chlorothiophenol; 2,3,4-chlorothiophenol;
3,4,5-chlorothiophenol; 2,3,4,5-tetrachlorothiophenol;
2,3,5,6-tetrachlorothiophenol; pentabromothiophenol;
2-bromothiophenol; 3-bromothiophenol; 4-bromothiophenol;
2,3-bromothiophenol; 2,4-bromothiophenol; 3,4-bromothiophenol;
3,5-bromothiophenol; 2,3,4-bromothiophenol; 3,4,5-bromothiophenol;
2,3,4,5-tetrabromothiophenol; 2,3,5,6-tetrabromothiophenol;
pentaiodothiophenol; 2-iodothiophenol; 3-iodothiophenol;
4-iodothiophenol; 2,3-iodothiophenol; 2,4-iodothiophenol;
3,4-iodothiophenol; 3,5-iodothiophenol; 2,3,4-iodothiophenol;
3,4,5-iodothiophenol; 2,3,4,5-tetraiodothiophenol;
2,3,5,6-tetraiodothiophenol; and their zinc salts, the metal salts
thereof, and mixtures thereof, but is preferably
pentachlorothiophenol or the metal salt thereof. The metal salt may
be zinc, calcium, potassium, magnesium, sodium, and lithium, but is
preferably zinc.
[0030] Additionally, suitable core materials may also include cast
or reaction injection molded polyurethane or polyurea, including
those versions referred to as nucleated, where a gas, typically
nitrogen, is incorporated via intensive agitation or mixing into at
least one component of the polyurethane. (Typically, the
pre-polymer, prior to component injection into a closed mold where
essentially full reaction takes place resulting in a cured polymer
having reduced specific gravity.) These materials are referred to
as reaction injection molded (RIM) materials. Alternatively, the
core may have a liquid center.
[0031] The use of various formulation modifications in the
polymeric composition may offer a plurality of means for
accomplishing the end result, which is a less dense intermediate or
cover layer.
[0032] In one embodiment, the invention involves the utilization of
a chemical blowing agent that is a thermally decomposable inorganic
blowing agent. Inorganic chemical agents may be preferred when the
layer is a thermoplastic such as an ionomer, highly neutralized
acid copolymer (HNP), polyolefin, etc. Some inorganic blowing
agents may comprise ammonium carbonate and carbonates of alkali
metals.
[0033] Organic blowing agents may include, but are not limited to
organics such as azo and diazo compounds including any of the
Celogens as manufactured by the Crompton Chemical Corporation, and
nitroso compounds, sulfonylhydrazides, azides of organic acids and
their analogs, triazines, tri- and tetrazole derivatives, sulfonyl
semicarbazides, urea derivatives, quanidine derivatives, and esters
such as alkoxyboroxines. Some chemical blowing agents liberate
gases as a result of chemical interaction between components such
as mixtures of acids and metals; mixtures of organic acids and
inorganic carbonates, mixtures of nitrites and ammonium salts and
the hydrolytic decomposition of urea.
[0034] Blowing agents can also be physical blowing agents that
typically may comprise volatile liquids, such as freons, other
halogenated hydrocarbons, water, aliphatic hydrocarbons, gases, and
solid blowing agents. The solid blowing agents typically are
adsorbents which include activated carbon, calcium carbonate,
diatomaceous earth and silicates saturated with carbon dioxide.
These adsorbents liberate gas as a result of desorption of gas.
Another method of delivering the physical blowing agent is the use
of hollow thermoplastic spheres that house a solvent, and upon the
application of infrared radiation the solvent expands into a gas
and thereby expanding the softened thermoplastic sphere. No matter
the type of blowing agent used, the object is that the intermediate
layer is less dense than the core layer and the cover layer is less
dense than the intermediate layer.
[0035] The principles of curing with IR would work equally as well
with one-piece, two-piece, multi-core, or multi-cover layered golf
balls. Infrared radiation can be used to cross-link any portion of
a golf ball, including the cover, coating and any intermediate
layer as well as a core layer.
[0036] In one embodiment, a layer is cured by exposure to IR
radiation wherein the post-curing (accelerated completion of cure)
with infrared radiation is particularly suited to the post-curing
of a polyurethane, polyurea, hybrid of the two, or the annealing of
a crystalline/semi-crystalline thermoplastic polymer such as a
partially or fully neutralized ionomer.
[0037] Intermediate and cover layers of golf balls may be
cross-linked utilizing infrared radiation techniques, particularly
to subassemblies of a thermoplastic layer comprising a peroxide
over a diene core layer. For example, ionomer or non-ionic
polyolefin comprising a high temperature half life peroxide may be
molded (as a thermoplastic) over a conventional diene core followed
by a post-molding infrared treatment that decomposes the peroxide
generating free radicals which cross-link the host polymer via
chain scission and subsequent initiation and/or via the reaction of
previously unreacted diene groups of an
ethylene-propylene-diene-monomer (EPDM) or polyisoprene, or styrene
ethylene butylenes (SEBS), etc. For cross-linking, preferably about
0.01 to 5.0 parts of a peroxide may be added, more preferably 0.05
to 2.0 parts. Any additional ingredients such as nucleating agents,
antioxidants, antizonants, processing aids such as metal salts of
fatty acids, amino fatty acids, waxes, glycols, metal oxides such
as zinc oxide, unsaturated coagents such as zinc diacrylate may
also be added. In addition to foaming agents, the use of specific
gravity lowering fillers/fibers/flakes/spheres/hollow
microspheres/microballoons such as 3M glass, ceramic (zeeospheres),
phenolic, as well as other polymer based such as Acrylonitrile,
PVDC, etc. may also be used to supplement the infrared activated
foaming/expansion agent.
[0038] Santoprene.RTM. 20340 is an example of a preferred
intermediate layer comprises of dynamically vulcanized
thermoplastic elastomer, functionalized styrene-butadiene
elastomer, thermoplastic polyurethane or metallocene polymer or
blends thereof. Suitable dynamically vulcanized thermoplastic
elastomers include Santoprene.RTM., Sarlink.RTM., Vyram.RTM.,
Dytron.RTM. and Vistaflex.RTM.. Santoprene.RTM. is the trademark
for a dynamically vulcanized elastomer and is commercially
available from Advanced Elastomer Systems. Examples of suitable
functionalized styrene-butadiene elastomers include Kraton FG-1901x
and FG-1921x, which is available from the Shell Corporation.
Examples of suitable thermoplastic polyurethanes include
Estane.RTM. 58133, Estane.RTM. 58134 and Estane.RTM. 58144, which
are commercially available from the B. F. Goodrich Company.
Suitable metallocene polymers whose melting points are higher than
the cover materials can also be employed in the intermediate layer
of the present invention. Further, the materials for the
intermediate layer described above may be in the form of a foamed
polymeric material. For example, suitable metallocene polymers
include foams of thermoplastic elastomers based on metallocene
single-site catalyst-based foams. Such metallocene-based foam
resins are commercially available from Sentinel Products of
Hyannis, Mass. Suitable thermoplastic polyetheresters include
Hytrel.RTM. 3078, Hytrel.RTM. 3548, Hytrel.RTM. 4078, Hytrel.RTM.
4069, Hytrel.RTM. 6356, Hytrel.RTM. 7246, and Hytrel.RTM. 8238
which are commercially available from DuPont. Suitable
thermoplastic polyetheramides include Pebax.RTM. 2533, Pebax.RTM.
3533, Pebax.RTM. 4033, Pebax.RTM. 5533, Pebax.RTM. 6333, and
Pebax.RTM. 7033 which are available from Elf-Atochem. Suitable
thermoplastic ionomer resins include any number of olefinic based
ionomers including SURLYN.RTM. and lotek.RTM., which are
commercially available from DuPont and Exxon, respectively. The
flexural moduli for these ionomers is about 1000 psi to about
200,000 psi. A suitable thermoplastic polyester is polybutylene
terephthalate. Likewise, the dynamically vulcanized thermoplastic
elastomers, functionalized styrene-butadiene elastomers,
thermoplastic polyurethane or metallocene polymers identified above
are also useful as the second thermoplastic in such blends.
Further, the materials of the second thermoplastic described above
may be in the form of a foamed polymeric material.
[0039] Such thermoplastic blends comprise about 1% to about 99% by
weight of a first thermoplastic and about 99% to about 1% by weight
of a second thermoplastic. Preferably the thermoplastic blend
comprises about 5% to about 95% by weight of a first thermoplastic
and about 5% to about 95% by weight of a second thermoplastic. In a
preferred embodiment of the present invention, the first
thermoplastic material of the blend is a thermoplastic
polyetherester, such as Hytrel.RTM..
[0040] The present invention also teaches the use of a variety of
non-conventional cover materials. In particular, the covers of the
present invention may comprise thermoplastic or engineering
plastics such as ethylene or propylene based homopolymers and
copolymers including functional monomers such as acrylic and
methacrylic acid and fully or partially neutralized ionomers and
their blends, methyl acrylate, methyl methacrylate homopolymers and
copolymers, imidized, amino group containing polymers,
polycarbonate, reinforced polyamides, polyphenylene oxide, high
impact polystyrene, polyether ketone, polysulfone, poly(phenylene
sulfide), reinforced engineering plastics, acrylonitrile-butadiene,
acrylic-styrene-acrylonitrile, poly(ethylene terephthalate),
poly(butylene terephthalate), poly(ethylene-vinyl alcohol),
poly(tetrafluoroethylene) and their copolymers including functional
comonomers and blends thereof. These polymers or copolymers can be
further reinforced by blending with a wide range of fillers and
glass fibers or spheres or wood pulp.
[0041] Additional preferred cover materials include thermoplastic
or thermosetting polyurethane, such as those disclosed in U.S. Pat.
Nos. 6,371,870; 6,210,294; 6,193,619; 5,908,358; 5,692,974; and
5,484,870; and metallocene or other single site catalyzed polymers
such as those disclosed in U.S. Pat. Nos. 5,824,746; 5,703,166;
6,150,462; and 5,981,658.
[0042] While it is apparent that the illustrative embodiments of
the invention herein disclosed fulfills the objectives stated
above, it will be appreciated that numerous modifications and other
embodiments may be devised by those skilled in the art. Therefore,
it will be appreciated that the appended claims are intended to
cover all such modifications and embodiments which come within the
spirit and scope of the present invention.
* * * * *