U.S. patent application number 11/152446 was filed with the patent office on 2005-11-10 for golf ball which includes fast-chemical-reaction-produced component and method of making same.
Invention is credited to Keller, Viktor, Kennedy, Thomas J. III, Risen, William M. JR., Tzivanis, Michael J..
Application Number | 20050250602 11/152446 |
Document ID | / |
Family ID | 23629914 |
Filed Date | 2005-11-10 |
United States Patent
Application |
20050250602 |
Kind Code |
A1 |
Kennedy, Thomas J. III ; et
al. |
November 10, 2005 |
Golf ball which includes fast-chemical-reaction-produced component
and method of making same
Abstract
Disclosed herein is a golf ball comprising
fast-chemical-reaction-produced component, such as a component
which comprises a reaction injection molded polyurethane material.
A process of making a golf ball by forming at least one core and/or
cover component of the ball by mixing two or more reactants that
react and form a reaction product with a flex modulus of 5-310 kpsi
in a reaction time of about 5 minutes or less, the component having
a thickness of at least 0.01 inches and a demold time of 10 minutes
or less is disclosed. In one preferred form of the invention,
excess polyurethane from forming golf ball covers is recycled by
using it to form golf ball cores.
Inventors: |
Kennedy, Thomas J. III;
(Wilbraham, MA) ; Tzivanis, Michael J.; (Chicopee,
MA) ; Keller, Viktor; (Beverly Hills, FL) ;
Risen, William M. JR.; (Rumford, RI) |
Correspondence
Address: |
MICHAEL A. CATANIA
CALLAWAY GOLF COMPANY
2180 RUTHERFORD ROAD
CARLSBAD
CA
92008-7328
US
|
Family ID: |
23629914 |
Appl. No.: |
11/152446 |
Filed: |
June 13, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11152446 |
Jun 13, 2005 |
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09877600 |
Jun 8, 2001 |
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6905424 |
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09877600 |
Jun 8, 2001 |
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09411690 |
Oct 1, 1999 |
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6290614 |
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09411690 |
Oct 1, 1999 |
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09040798 |
Mar 18, 1998 |
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6855073 |
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Current U.S.
Class: |
473/371 ;
473/378 |
Current CPC
Class: |
A63B 37/0076 20130101;
A63B 37/0075 20130101; A63B 37/12 20130101; A63B 37/0003 20130101;
A63B 45/00 20130101; A63B 37/0037 20130101; A63B 37/0049 20130101;
A63B 37/0054 20130101; A63B 37/0069 20130101; A63B 37/0031
20130101; A63B 37/0051 20130101; A63B 2209/00 20130101; C08G
2120/00 20130101; Y02P 20/582 20151101; A63B 37/0052 20130101; A63B
37/0045 20130101; C08L 75/04 20130101; A63B 37/0053 20130101; A63B
37/0033 20130101; A63B 37/06 20130101; A63B 37/0058 20130101 |
Class at
Publication: |
473/371 ;
473/378 |
International
Class: |
A63B 037/12 |
Claims
We claim as our invention:
1. A golf ball comprising: a core comprising a composition
comprising a polybutadiene material; a mantle layer comprising a
reaction injection molded polyurethane; and a cover disposed over
the mantle layer, the cover comprising a composition comprising an
ionomer material.
2. The golf ball according to claim 1 wherein the mantle layer has
a thickness of approximately 0.04 inch.
3. The golfball according to claim 1wherein the core has a diameter
of approximately 1.49 inches.
4. The golf ball according to claim 1 wherein the cover has a
thickness of approximately 0.055 inch.
5. The golf ball according to claim 1 wherein the mantle layer is
thinner than the cover.
6. A golf ball comprising: a core comprising a composition
comprising a polybutadiene material; a mantle layer comprising a
composition formed from reaction injection molding a polyol
component and a diisocyanate component; and a cover disposed over
the mantle layer, the cover comprising a composition comprising an
ionomer material.
7. A golf ball comprising: a core comprising a composition
comprising a polybutadiene material, the core having a diameter of
approximately 1.49 inches; a mantle layer comprising a composition
formed from reaction injection molding a polyol component and a
diisocyanate component; and a cover disposed over the mantle layer,
the cover comprising a composition comprising an ionomer material,
the cover having a Shore D hardness of approximately 57.
Description
CROSS REFERENCES TO RELATED APPLICATIONS
[0001] This application is a continuation application of U.S.
patent application Ser. No. 09/877,600, filed on Jun. 8, 2001,
which is a continuation application of U.S. patent application Ser.
No. 09/411,690, filed on Oct. 1, 1999, now U.S. patent No., which
is a continuation-in-part application of U.S. patent application
Ser. No. 09/040,798, filed on Mar. 18, 1998, now U.S. Pat. No.
6,855,073.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
[0002] Not Applicable
BACKGROUND OF THE INVENTION
[0003] The invention relates generally to golf balls, and more
particularly to golf balls which contain a
fast-chemical-reaction-produce- d component, such as a core and/or
cover layer.
[0004] Golf balls comprise, in general, three types. The first type
is a multi-piece wound ball wherein a vulcanized rubber thread is
wound under tension around a solid or semi-solid core, and
thereafter enclosed in a single or multi-layer covering of a tough,
protective material. A second type of a golfball is a one-piece
ball formed from a solid mass of resilient material which has been
cured to develop the necessary degree of hardness to provide
utility. One-piece molded balls do not have a second enclosing
cover. A third type of ball is a multi-piece non-wound ball which
includes a liquid, gel or solid core of one or more layers and a
cover having one or more layers formed over the core.
[0005] Conventional golf ball covers have been made of ionomer,
balata, and slow-reacting, thermoset polyurethane. When
polyurethane covers are made by conventional methods, such as by
casting, a substantial amount of time and energy are required, thus
resulting in relatively high cost.
[0006] It would be usefull to develop a golf ball containing a
fast-chemical-reaction-produced component, such as at least one
core or cover layer, particularly one which contains polyurethane,
polyurea, epoxy and/or unsaturated polyester.
BRIEF SUMMARY OF THE INVENTION
[0007] An object of the invention is to produce a golf ball having
a polyurethane cover which is formed by a fast chemical
reaction.
[0008] Another object of the invention is to provide a
non-ionomeric golf ball cover which is efficiently produced by
injection molding.
[0009] Yet another object of the invention is to provide a golf
ball which contains polyurethane.
[0010] A further object of the invention is to provide a golf ball
in which material from recycling polyurethane can be used to result
in an efficient manufacturing process.
[0011] A further object of the invention is to produce a durable
golf ball containing polyurethane, polyurea, epoxy, and/or
unsaturated polyesters.
[0012] Another object of the invention is to provide a golf ball
with a "seamless" cover layer, i.e., a cover layer having generally
the same microscopic and molecular structure distribution both in
the regions adjacent to the parting line of the mold and at
locations which are not adjacent to the parting line, including
near the poles.
[0013] Yet another object of the invention is to provide a method
of making a golf ball of the type described above.
[0014] Other objects of the invention will become apparent from the
specification, drawings and claims.
[0015] A preferred form of the invention is a method of making a
multi-piece golf ball comprising making at least one of a cover
component and a core component of the ball by mixing two or more
materials that react to form a reaction product with a flex modulus
of 5-310 kpsi in a reaction time of about 5 minutes or less, the
component having a thickness of at least 0.01 inches and a demold
time of 10 minutes or less including the reaction time.
[0016] The composition preferably comprises at least one member
selected from the group consisting of polyurethanes, polyureas,
epoxies and unsaturated polyesters. The reaction product preferably
is formed by reaction injection molding. The component preferably
has a thickness of at least 0.02 inches.
[0017] Another preferred form of the invention is a multi-piece
golf ball comprising a reaction injection molded material
comprising polyurethane/polyurea. The golfball cover preferably has
a Shore D hardness in the range of 20-95, more preferably 30-75,
and a flex modulus in the range of 5-310 kpsi, and more preferably
5-100 kpsi and even more preferably 10-80 kpsi. Preferably at least
5% of the polyurethane/polyurea is formed from molecules obtained
by recycling a material comprising at least one of polyurethane,
polyurea, polyester and polyethylene glycol.
[0018] Yet another preferred form of the invention is a process for
producing a golf ball including the step of reaction injection
molding a polyurethane/polyurea material to form at least one of a
core layer and a cover layer of the ball.
[0019] A further preferred form of the invention is a process for
producing a golfball comprising the steps of (a) reaction injection
molding a polyurethane/polyurea component of the ball, and (b)
recycling some of the polyurethane and/or polyurea that is produced
in connection with step (a) but that is not incorporated in the
golf ball in step (a). The polyurethane/polyurea preferably, but
not necessarily, is recycled by glycolysis.
[0020] Yet another preferred form of the invention is a process for
producing a golfball comprising (a) forming a core, (b) covering
the core, and (c) coating and adding indicia to the covered ball,
wherein at least one of steps (a) and (b) comprises reaction
injection molding of a polyurethane and/or polyurea material.
[0021] The golf ball of the invention can include, in the cover,
optical brighteners, white pigment, UV stabilizers, antioxidants,
etc. The cover and/or core may further include fillers such as
TiO.sub.2, glass, metal, and other fillers described below.
[0022] Yet another preferred form of the invention is a golf ball
having a cover comprising a blend of polyurethane and ionomer,
wherein the ionomer is a partially cation neutralized organic acid
polymer, preferably an alpha, beta unsaturated carboxylic acid with
3 or more carbon atoms. The ionomer may be a polyurethane
ionomer.
[0023] A further preferred form of the invention is a golf ball
comprising at least one fast-chemical-reaction-produced layer, said
layer having a flex modulus of 5-300 kpsi in a reaction time of 5
minutes or less and a thickness of at least 0.01".
[0024] Yet another preferred form of the invention is a golfball
having a core and a cover, the cover comprising
polyurethane/polyurea which is formed from reactants, 5-100 weight
percent of which are obtained from recycled polyurethane.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0025] FIG. 1 is a first embodiment of a golf ball formed according
to a reaction injection molded (RIM) process according to the
invention.
[0026] FIG. 2 is a second embodiment of a golf ball formed
according to a reaction injection molded (RIM) process according to
the invention.
[0027] FIG. 3 is a third embodiment of a golf ball formed according
to a reaction injection molded (RIM) process according to the
invention.
[0028] FIG. 4 is a process flow diagram which schematically depicts
a reaction injection molding process according to the
invention.
[0029] FIG. 5 schematically shows a mold for reaction injection
molding a golfball cover according to the invention.
[0030] FIG. 6 is a schematic illustration of a hitting chamber used
to conduct durability tests.
[0031] FIG. 7 is a detailed view of a portion of an insert plate
used in the hitting chamber shown in FIG. 6, which contains a
series of grooves that contact a golf ball.
DETAILED DESCRIPTION OF THE INVENTION
[0032] The present invention is a golf ball in which at least one
cover or core layer is a fast-chemical-reaction-produced component.
This component comprises at least one material selected from the
group consisting of polyurethane, polyurea, polyurethane ionomer,
epoxy, and unsaturated polyesters, and preferably comprises
polyurethane. The invention also includes a method of producing a
golf ball which contains a fast-chemical-reaction-produced
component. A golf ball formed according to the invention preferably
has a flex modulus in the range of 5-310 kpsi, a Shore D hardness
in the range of 20-90, and good durability.
[0033] Particularly preferred forms of the invention also provide
for a golf ball with a fast-chemical-reaction-produced cover having
good scuff resistance and cut resistance. As used herein,
"polyurethane and/or polyurea" is expressed as
"polyurethane/polyurea".
[0034] A particularly preferred form of the invention is a golf
ball with a cover comprising polyurethane, the cover including
5-100 weight percent of polyurethane formed from recycled
polyurethane.
[0035] The method of the invention is particularly usefull in
forming golf balls because it can be practiced at relatively low
temperatures and pressures. The preferred temperature range for the
method of the invention is 120-180.degree. F. when the component
being produced contains polyurethane. Preferred pressures for
practicing the invention using polyurethane-containing materials
are 200 psi or less and more preferably 100 psi or less. The method
of the present invention offers numerous advantages over
conventional slow-reactive process compression molding of golf ball
covers. The method of the present invention results in molded
covers in a demold time of 10 minutes or less. An excellent finish
can be produced on the ball.
[0036] The method of the invention also is particularly effective
when recycled polyurethane or other polymer resin, or materials
derived by recycling polyurethane or other polymer resin, is
incorporated into the product.
[0037] As indicated above, the fast-chemical-reaction-produced
component can be one or more cover and/or core layers of the ball.
When a polyurethane cover is formed according to the invention and
is then covered with a polyurthane top coat, excellent adhesion can
be obtained. The adhesion in this case is better than adhesion of a
polyurethane coating to an ionomeric cover. This improved adhesion
can result in the use of a thinner top coat, the elimination of a
primer coat, and the use of a greater variety of golf ball printing
inks beneath the top coat. These include but are not limited to
typical inks such as one component polyurethane inks and two
component polyurethane inks.
[0038] The preferred method of forming a
fast-chemical-reaction-produced component for a golf ball according
to the invention is by reaction injection molding (RIM). RIM is a
process by which highly reactive liquids are injected into a closed
mold, mixed usually by impingement and/or mechanical mixing in an
in-line device such as a "peanut mixer", where they polymerize
primarily in the mold to form a coherent, one-piece molded article.
The RIM processes usually involve a rapid reaction between one or
more reactive components such as polyether-or polyester-polyol,
polyamine, or other material with an active hydrogen, and one or
more isocyanate-containing constituents, often in the presence of a
catalyst. The constituents are stored in separate tanks prior to
molding and may be first mixed in a mix head upstream of a mold and
then injected into the mold. The liquid streams are metered in the
desired weight to weight ratio and fed into an impingement mix
head, with mixing occurring under high pressure, e.g., 1500-3000
psi. The liquid streams impinge upon each other in the mixing
chamber of the mix head and the mixture is injected into the mold.
One of the liquid streams typically contains a catalyst for the
reaction. The constituents react rapidly after mixing to gel and
form polyurethane polymers. Polyureas, epoxies, and various
unsaturated polyesters also can be molded by RIM.
[0039] RIM differs from non-reaction injection molding in a number
of ways. The main distinction is that in RIM a chemical reaction
takes place in the mold to transform a monomer or adducts to
polymers and the components are in liquid form. Thus, a RIM mold
need not be made to withstand the pressures which occur in a
conventional injection molding. In contrast, injection molding is
conducted at high molding pressures in the mold cavity by melting a
solid resin and conveying it into a mold, with the molten resin
often being at about 150-350.degree. C. At this elevated
temperature, the viscosity of the molten resin usually is in the
range of 50,000-1,000,000 centipoise, and is typically around
200,000 centipoise. In an injection molding process, the
solidification of the resins occurs after about 10-90 seconds,
depending upon the size of the molded product, the temperature and
heat transfer conditions, and the hardness of the injection molded
material. Subsequently, the molded product is removed from the
mold. There is no significant chemical reaction taking place in an
injection molding process when the thermoplastic resin is
introduced into the mold. In contrast, in a RIM process, the
chemical reaction typically takes place in less than about two
minutes, preferably in under one minute, and in many cases in about
30 seconds or less.
[0040] If plastic products are produced by combining components
that are performed to some extent, subsequent failure can occur at
a location on the cover which is along the seam or parting line of
the mold. Failure can occur at this location because this
interfacial region is intrinsically different from the remainder of
the cover layer and can be weaker or more stressed. The present
invention is believed to provide for improved durability of a golf
ball cover layer by providing a uniform or "seamless" cover in
which the properties of the cover material in the region along the
parting line are generally the same as the properties of the cover
material at other locations on the cover, including at the poles.
The improvement in durability is believed to be a result of the
fact that the reaction mixture is distributed uniformly into a
closed mold. This uniform distribution of the injected materials
eliminates knit-lines and other molding deficiencies which can be
caused by temperature difference and/or reaction difference in the
injected materials. The process of the invention results in
generally uniform molecular structure, density and stress
distribution as compared to conventional injection-molding
processes.
[0041] The fast-chemical-reaction-produced component has a flex
modulus of 5-310 kpsi, more preferably 5-100 kpsi, and most
preferably 5-50 kpsi. The subject component can be a cover with a
flex modulus which is higher than that of the centermost component
of the cores, as in a liquid center core and some solid center
cores. Furthermore, the fast-chemical-reaction-produced component
can be a cover with a flex modulus that is higher than that of the
immediately underlying layer, as in the case of a wound core. The
core can be one piece or multi-layer, each layer can be either
foamed or unfoamed, and density adjusting fillers, including
metals, can be used. The cover of the ball can be harder or softer
than any particular core layer.
[0042] The fast-chemical-reaction-produced component can
incorporate suitable additives and/or fillers. When the component
is an outer cover layer, pigments or dyes, accelerators and UV
stabilizers can be added. Examples of suitable optical brighteners
which probably can be used include Uvitex and Eastobrite OB-1. An
example of a suitable white pigment is titanium dioxide. Examples
of suitable and UV light stabilizers are provided in commonly
assigned U.S. Pat. No. 5,494,291. Fillers which can be incorporated
into the fast-chemical-reaction-produce- d cover or core component
include those listed below in the definitions section. Furthermore,
compatible polymeric materials can be added. For example, when the
component comprises polyurethane and/or polyurea, such polymeric
materials include polyurethane ionomers, polyamides, etc.
[0043] A golf ball core layer formed from a
fast-chemical-reaction-produce- d material according to the present
invention typically contains 0-20 weight percent of such filler
material, and more preferably 1-15 weight percent. When the
fast-chemical-reaction-produced component is a core, the additives
typically are selected to control the density, hardness and/or
COR.
[0044] A golf ball inner cover layer formed from a
fast-chemical-reaction-- produced material according to the present
invention typically contains 0-60 weight percent of filler
material, more preferably 1-30 weight percent, and most preferably
1-20 weight percent.
[0045] A golf ball outer cover layer formed from a
fast-chemical-reaction-- produced material according to the present
invention typically contains 0-20 weight percent of filler
material, more preferably 1-10 weight percent, and most preferably
1-5 weight percent.
[0046] Catalysts can be added to the RIM polyurethane system
starting materials as long as the catalysts generally do not react
with the constituent with which they are combined. Suitable
catalysts include those which are known to be useful with
polyurethanes and polyureas.
[0047] The reaction mixture viscosity should be sufficiently low to
ensure that the empty space in the mold is completely filled. The
reactant materials generally are preheated to 100-150.degree. F.
before they are mixed. In most cases it is necessary to preheat the
mold to, e.g., 100-120.degree. F., to ensure proper injection
viscosity.
[0048] As indicated above, one or more cover layers of a golf ball
can be formed from a fast-chemical-reaction-produced material
according to the present invention.
[0049] Referring now to the drawings, and first to FIG. 1, a golf
ball having a cover comprising a RIM polyurethane is shown. The
golf ball 10 includes a polybutadlene core 12 and a polyurethane
cover 14 formed by RIM.
[0050] Referring now to FIG. 2, a golf ball having a core
comprising a RIM polyurethane is shown. The golf ball 20 has a RIM
polyurethane core 22, and a RIM polyurethane cover 24.
[0051] Referring to FIG. 3, a multi-layer golf ball 30 is shown
with a solid core 32 containing recycled RIM polyurethane, a mantle
cover layer comprising RIM polyurethane, and an outer cover layer
comprising ionomer or another conventional golfball cover material.
Non-limiting examples of multi-layer golf balls according to the
invention with two cover layers include those with RIM polyurethane
mantles having a thickness of 0.02-0.20 inches and a Shore D
hardness of 20- 80, covered with ionomeric or non-ionomeric
thermoplastic, balata or other covers having a Shore D hardness of
20-80 and a thickness of 0.025-0.20 inches.
[0052] Referring next to FIG. 4, a process flow diagram for forming
a RIM cover of polyurethane is shown. Isocyanate from bulk storage
is fed through line 80 to an isocyanate tank 100. The isocyanate is
heated to the desired temperature, e.g. 100-120.degree. F., by
circulating it through heat exchanger 82 via lines 84 and 86.
Polyol, polyamine, or another compound with an active hydrogen atom
is conveyed from bulk storage to a polyol tank 108 via line 88. The
polyol is heated to the desired temperature, e.g. 100-120.degree.
F., by circulating it through heat exchanger 90 via lines 92 and
94. Dry nitrogen gas is fed from nitrogen tank 96 to isocyanate
tank 100 via line 97 and to polyol tank 108 via line 98. Isocyanate
is fed from isocyanate tank 100 via line 102 through a metering
cylinder or metering pump 104 into recirculation mix head inlet
line 106. Polyol is fed from polyol tank 108 via line 110 through a
metering cylinder or metering pump 112 into a recirculation mix
head inlet line 114. The recirculation mix head 116 receives
isocyanate and polyol, mixes them, and provides for them to be fed
through nozzle 118 into injection mold 120. The injection mold 120
has a top mold 122 and a bottom mold 124. Coolant flows through
cooling lines 126 in the top mold 122 and lines 128 in the bottom
mold 124. The materials are kept under controlled temperature
conditions to insure that the desired reaction profile is
maintained.
[0053] The polyol component typically contains additives, such as
stabilizers, flow modifiers, catalysts, combustion modifiers,
blowing agents, fillers, pigments, optical brighteners, and release
agents to modify physical characteristics of the cover. Recycled
polyurethane/polyurea also can be added to the core.
Polyurethane/polyurea constituent molecules that were derived from
recycled polyurethane can be added in the polyol component.
[0054] Inside the mix head, injector nozzles impinge the isocyanate
and polyol at ultra-high velocity to provide excellent mixing.
Additional mixing preferably is conducted using an aftermixer 130,
which typically is constructed inside the mold between the mix head
and the mold cavity.
[0055] As is shown in FIG. 5, the mold includes a golf ball cavity
chamber 132 in which a spherical golf ball mold 134 with a dimpled,
spherical mold cavity 136 is positioned. The aftermixer 130 can be
a peanut aftermixer, as is shown in FIG. 5, or in some cases
another suitable type, such as a heart, harp or dipper. An overflow
channel 138 receives overflow material from the golfball mold 134
through a shallow vent 136. Cooling water passages 138, which
preferably are in a parallel flow arrangement, carry cooling water
through the top mold 122 and the bottom mold 124.
[0056] The mold cavity contains retractable pins and is generally
constructed in the same manner as a mold cavity used to injection
mold a thermoplastic, e.g., ionomeric golf ball cover. However, a
few differences when RIM is used are that tighter pin tolerances
generally are required, a lower mold temperature is used, and a
lower injection pressure is used. Also, the molds can be produced
from lower strength material such as aluminum.
[0057] The golfballs formed according to the present invention can
be coated using a conventional two-component spray coating or can
be coated during the RIM process, i.e., using an in-mold coating
process.
[0058] One of the significant advantages of the RIM process
according to the invention is that polyurethane or other cover
material can be recycled and used in golfball cores. Recycling can
be conducted by, e.g., glycolysis. Typically, 10-80% of the
material which is injection molded actually becomes part of the
cover. The remaining 20-90% is recycled.
[0059] Recycling of polyurethanes by glycolysis is known from, for
example, RIM Part and Mold Design-Polyurethanes, 1995, Bayer Corp.,
Pittsburgh, Pa. Another significant advantage of the present
invention is that because reaction injection molding occurs at low
temperatures and pressures, i.e., 120-180.degree. F. and 100-200
psi, this process is particularly beneficial when a cover is to be
molded over a very soft core. When higher pressures are used for
molding over soft cores, the cores "shut off" i.e., deform and
impede the flow of material causing uneven distribution of cover
material.
[0060] One polyurethane component which can be used in the present
invention incorporates TMXDI (META) aliphatic isocyanate (Cytec
Industries, West Paterson, N.J.). Polyurethanes based on
meta-tetramethylxylyliene diisocyanate can provide improved gloss
retention UV light stability, thermal stability hydrolytic
stability. Additionally, TMXDI (META) aliphatic isocyanate has
demonstrated favorable toxicological properties. Furthermore,
because it has a low viscosity, it is usable with a wider range of
diols (to polyurethane) and diamines (to polyureas). If TMXDI is
used, it typically, but not necessarily, is added as a direct
replacement for some or all of the other aliphatic isocyanates in
accordance with the suggestions of the supplier. Because of slow
reactivity of TMXDI, it may be useful or necessary to use catalysts
to have practical demolding times. Hardness, tensile strength and
elongation can be adjusted by adding further materials in
accordance with the supplier's instructions.
[0061] Golfball cores also can be made using the materials and
processes of the invention. To make a golf ball core using RIM
polyurethane, the same processing conditions are used as are
described above with respect to covers. One difference is, of
course, that no retractor pins are needed in the mold. Furthermore,
an undimpled, smaller mold is used. If, however, a one piece ball
is desired, a dimpled mold would be used. Polyurethanes also can be
used for cores.
[0062] Golf balls typically have indicia and/or logos stamped or
formed thereon. Such indicia can be applied by printing using a
material or a source of energetic particles after the ball core
and/or cover have been reaction-injection-molded according to the
present invention. Printed indicia can be formed form a material
such as ink, foil (for use in foil transfer), etc. Indicia printed
using a source of energetic particles or radiation can be applied
by burning with a laser, burning with heat, directed electrons, or
light, phototransformations of, e.g., UV ink, impingement by
particles, impingement by electromagnetic radiation etc.
Furthermore, the indicia can be applied in the same manner as an
in-mold coating, i.e., by applying to the indicia to the surface of
the mold prior to molding of the cover.
[0063] The polyurethane which is selected for use as a golf ball
cover preferably has a Shore D hardness of 40-75, more preferably
40-60, and most preferably 40-50 for a soft cover layer and 50-60
for a hard cover layer. The polyurethane which is to be used for a
cover layer preferably has a flex modulus of 5-310 kpsi, more
preferable 5-100 kpsi, and most preferably 5-20 kpsi for a soft
cover layer and 30-40 kpsi for a hard cover layer.
[0064] Non-limiting examples of suitable RIM systems for use in the
present invention are Bayflex.RTM. elastomeric polyurethane RIM
systems, Baydur.RTM. GS solid polyurethane RIM systems, Prism.RTM.
solid polyurethane RIM systems, all from Bayer Corp. (Pittsburgh,
Pa.), SPECTRIM reaction moldable polyurethane and polyurea systems
from Dow Chemical USA (Midland, Mich.), including SPECTRIM MM 373-A
(isocyanate) and 373-B (polyol), and Elastolit SR systems from BASF
(Parsippany, N.J.). Preferred RIM systems include Bayflex.RTM.
MP-10000 and Bayflex.RTM. 110-50, filled and unfilled. Further
preferred examples are polyols, polyamines and isocyanates formed
by processes for recycling polyurethanes and polyureas. Peroxides,
such as MEK-peroxide and dicumyl peroxide can be used. Furthermore,
catalysts or activators such as cobalt octoate 6% can be used.
[0065] The following examples are included for purposes of
illustration and are not intended to be limiting.
EXAMPLE 1
[0066] A polybutadiene golfball core having a diameter of 1.545", a
PGA compression of about 65 and a coefficient of restitution of
about 0.770 was obtained. A dimpled cover having a thickness of
0.0675" was reaction injection molded over the core. The cover
comprised Bayflex MP 10000 resin (Bayer). The resulting ball had a
PGA compression of 78, a COR of 0.720 and a Shore D cover hardness
of 39. The ball met standard durability tests and had an excellent
scuff resistance rating of 1. It is expected that this cover also
has an excellent cut resistance rating.
EXAMPLE 2
Prophetic
[0067] A golf ball core formed from high cis polybutadiene, zinc
diacrylate, zinc oxide, zinc stearate, and peroxide initiator is
obtained. The core has a diameter of 1.49".
[0068] The core is covered with a 0.04" thick mantle layer of RIM
polyurethane which has a plaque Shore D hardness of 58, namely
Bayflex.RTM. 110-50 unfilled (Bayer Corp.). The mantle layer is
covered with a 0.055" thick dimpled outer cover layer of lotek
8000, 7510 and 7030, and a whitener package. The formulation and
properties of the golf ball are shown below on Table 1.
EXAMPLE 3
Prophetic
[0069] A golfball core formed from high-cis polyburadiene, zinc
diacryiate, zinc oxide, zinc stearate and peroxide imitator is
obtained. The core has a diameter of 1.49".
[0070] The core is covered with a 0.040" thick mantle layer of RIM
polyurethane having a plaque Shore A hardness of about 90, namely
Bayflex.RTM. MP 10000 unfilled (Bayer Corp.). The mantle layer is
covered with a 0.055" thick dimpled outer cover layer of Ex 1006
and 1007 (Exxon Corp.) and lotek 7030 (Exxon Corp.). The
formulations and properties of the golf ball are shown below in
Table 1.
EXAMPLE 4
Prophetic
[0071] A golf ball core formed from high-cis polybutadiene, zinc
diacrylate, zinc oxide, zinc stearate, and peroxide initiator is
obtained. The core has a diameter of 1.49".
[0072] The core is covered with a 0.055" thick mantle layer of
lotek 1002 and 1003 (Exxon Corp.). The mantle layer is covered with
a 0.04" thick dimpled outer cover layer of RIM Bayflex.RTM. MP
10000 unfilled (Bayer Corp.). The formulation and properties of the
golf ball are shown below on Table 1.
EXAMPLE 5
Prophetic
[0073] A golf ball core having a diameter of 1.42" is formed from
an elastomeric unfilled RIM polyurethane (Bayflex.RTM. MP10000,
Bayer Corp.). The core is covered with a 0.08" thick
injection-molded mantle layer of 50 parts by weight lotek 1002 and
50 parts by weight lotek 1003. The mantle layer is covered with a
0.050" thick injection-molded outer cover layer of Ex 1006, Ex
1007, lotek 7030, and whitener. The formulation and properties of
the golf ball are shown below on Table 1.
1TABLE 1 Example Example Example Example Chemical Component 2 3 4 5
Core Data Size 1.49" 1.49" 1.49" 1.42" Type Polybutadiene Y Y Y --
RIM Polyurethane -- -- -- Y Inner Cover Layer Size 1.57" 1.57"
1.57" 1.58" Weight 38 g -- 38 g -- Thickness 0.040" 0.040" 0.055"
0.080" Hardness (Shore A or D) 58D 90A 70D 70D plaque plaque
Composition (wt %) Iotek 1002 -- -- 50.00 50.00 Iotek 1003 -- --
50.00 50.00 Bayflex 110-50 100.00 -- -- -- unfilled Bayflex MP
10000 -- 100.00 -- -- Hardness (Shore A or D) 57D 64D 90A 64D
plaque Thickness 0.055" 0.055" 0.040" 0.050" Composition (wt %)
Bayflex MP 10000 -- -- 100.00 -- Exxon 1006 -- 46.40 -- 46.40 Exxon
1007 -- 46.40 -- 46.40 Iotek 8000 33.8% -- -- -- Iotek 7510 58.9%
-- -- -- Iotek 7030 7.30 7.20 -- 7.20 Whitener Package Unitane
0-110 (phr) 2.30 2.30 2.30 2.30 Eastobrite OB1 (phr) 0.025 0.025
0.025 0.025 Ultra Marine Blue (phr) 0.004 0.004 0.004 0.004 Final
Ball Data Size 1.68" 1.68" 1.68" 1.68" Weight 45.4 g 45.4 g 45.4 g
45.4 g COR (.times.1000) 770-780 770-780 770-780 770-780
DEFINITIONS
[0074] Fillers
[0075] In a particularly preferred form of the invention, at least
one layer of the golfball contains at least one part by weight of a
filler. Fillers preferably are used to adjust the density, flex
modulus, mold release, and/or melt flow index of a layer. More
preferably, at least when the filler is for adjustment of density
or flex modulus of a layer, it is present in an amount of at least
five parts by weight based upon 100 parts by weight of the layer
composition. With some fillers, up to about 200 parts by weight
probably can be used.
[0076] A density adjusting filler according to the invention
preferably is a filler which has a specific gravity which is at
least 0.05 and more preferably at least 0.1 higher or lower than
the specific gravity of the layer composition. Particularly
preferred density adjusting fillers have specific gravities which
are higher than the specific gravity of the resin composition by
0.2 or more, even more preferably by 2.0 or more.
[0077] A flex modulus adjusting filler according to the invention
is a filler which, when used in an amount of e.g. 1-100 parts by
weight based upon 100 parts by weight of resin composition, will
raise or lower the flex modulus (ASTM D-790) of the resin
composition by at least 1% and preferably at least 5% as compared
to the flex modulus of the resin composition without the inclusion
of the flex modulus adjusting filler.
[0078] A mold release adjusting filler is a filler which allows for
the easier removal of a part from a mold, and eliminates or reduces
the need for external release agents which otherwise could be
applied to the mold. A mold release adjusting filler typically is
used in an amount of up to about 2 weight percent based upon the
total weight of the layer.
[0079] A melt flow index adjusting filler is a filler which
increases or decreases the melt flow, or ease of processing of the
composition.
[0080] The layers may contain coupling agents that increase
adhesion of materials within a particular layer e.g. to couple a
filler to a resin composition, or between adjacent layers.
Non-limiting examples of coupling agents include titanates,
zirconates and silanes. Coupling agents typically are used in
amounts of 0.1-2 weight percent based upon the total weight of the
composition in which the coupling agent is included.
[0081] A density adjusting filler is used to control the moment of
inertia, and thus the initial spin rate of the ball and spin decay.
The addition in one or more layers, and particularly in the outer
cover layer of a filler with a lower specific gravity than the
resin composition results in a decrease in moment of inertia and a
higher initial spin rate than would result if no filler were used.
The addition in one or more of the cover layers, and particularly
in the outer cover layer of a filler with a higher specific gravity
than the resin composition, results in an increase in moment of
inertia and a lower initial spin rate. High specific gravity
fillers are preferred as less volume is used to achieve the desired
inner cover total weight. Nonreinforcing fillers are also preferred
as they have minimal effect on COR. Preferably, the filler does not
chemically react with the resin composition to a substantial
degree, although some reaction may occur when, for example, zinc
oxide is used in a shell layer which contains some ionomer.
[0082] The density-increasing fillers for use in the invention
preferably have a specific gravity in the range of 1.0-20. The
density-reducing fillers for use in the invention preferably have a
specific gravity of 0.06-1.4, and more preferably 0.06-0.90. The
flex modulus increasing fillers have a reinforcing or stiffening
effect due to their morphology, their interaction with the resin,
or their inherent physical properties. The flex modulus reducing
fillers have an opposite effect due to their relatively flexible
properties compared to the matrix resin. The melt flow index
increasing fillers have a flow enhancing effect due to their
relatively high melt flow versus the matrix. The melt flow index
decreasing fillers have an opposite effect due to their relatively
low melt flow index versus the matrix.
[0083] Fillers which may be employed in layers other than the outer
cover layer may be or are typically in a finely divided form, for
example, in a size generally less than about 20 mesh, preferably
less than about 100 mesh U.S. standard size, except for fibers and
flock, which are generally elongated. Flock and fiber sizes should
be small enough to facilitate processing. Filler particle size will
depend upon desired effect, cost, ease of addition, and dusting
considerations. The filler preferably is selected from the group
consisting of precipitated hydrated silica, clay, talc, asbestos,
glass fibers, aramid fibers, mica, calcium metasilicate, barium
sulfate, zinc sulfide, lithopone, silicates, silicon carbide,
diatomaceous earth, polyvinyl chloride, carbonates, metals, metal
alloys, tungsten carbide, metal oxides, metal stearates,
particulate carbonaceous materials, micro balloons, and
combinations thereof. Non-limiting examples of suitable fillers,
their densities, and their preferred uses are as follows:
2 FILLER TABLE Filler Type Spec. Grav. Comments Precipitated
hydrated silica 2.00 1, 2 Clay 2.62 1, 2 Talc 2.85 1, 2 Asbestos
2.50 1, 2 Glass fibers 2.55 1, 2 Aramid fibers (KEVLAR .RTM.) 1.44
1, 2 Mica 2.80 1, 2 Calcium metasilicate 2.90 1, 2 Barium sulfate
4.60 1, 2 Zinc sulfide 4.10 1, 2 Lithopone 4.2- 1, 2 4.3 Silicates
2.10 1, 2 Silicon carbide platelets 3.18 1, 2 Silicon carbide
whiskers 3.20 1, 2 Tungsten carbide 15.60 1.00 Diatomaceous earth
2.30 1, 2 Polyvinyl chloride 1.41 1, 2 Carbonates Calcium carbonate
2.71 1, 2 Magnesium carbonate 2.20 1, 2 Metals and Alloys (powders)
Titanium 4.51 1.00 Tungsten 19.35 1.00 Aluminum 2.70 1.00 Bismuth
9.78 1.00 Nickel 8.90 1.00 Molybdenum 10.20 1.00 Iron 7.86 1.00
Steel 7.8- 1.00 7.9 Lead 11.40 1, 2 Copper 8.94 1.00 Brass 8.2-
1.00 8.4 Boron 2.34 1.00 Boron carbide whiskers 2.52 1, 2 Bronze
8.70- 1.00 8.74 Cobalt 8.92 1.00 Beryllium 1.84 1.00 Zinc 7.14 1.00
Tin 7.31 1.00 Metal Oxides Zinc oxide 5.57 1, 2 Iron oxide 5.10 1,
2 Aluminum oxide 4.00 Titanium oxide 3.9- 1, 2 4.1 Magnesium oxide
3.3- 1, 2 3.5 Zirconium oxide 5.73 1, 2 Metal Stearates Zinc
stearate 1.09 3, 4 Calcium stearate 1.03 3, 4 Barium stearate 1.23
3, 4 Lithium stearate 1.01 3, 4 Magnesium stearate 1.03 3, 4
Prticulate carbonaceous materials Graphite 1.5- 1, 2 1.8 Carbon
black 1.80 1, 2 Natural bitumen 1.2- 1, 2 1.4 Cotton flock 1.3- 1,
2 1.4 Cellulose flock 1.15- 1, 2 1.5 Leather fiber 1.2- 1, 2 1.4
Micro balloons Glass 0.15- 1, 2 1.1 Ceramic 0.2- 1, 2 0.7 Fly ash
0.6- 1, 2 0.8 Coupling Agents Adhesion Promoters Titanates 0.95-
1.17 Zirconates 0.92- 1.11 Silane 0.95- 1.2 COMMENTS: 1
Particularly useful for adjusting density of the cover layer. 2
Particularly useful for adjusting flex modulus of the cover layer.
3 Particularly useful for adjusting mold release of the cover
layer. 4 Particularly useful for increasing melt flow index of the
cover layer.
[0084] All fillers except for metal stearates would be expected to
reduce the melt flow index of an injection molded cover layer.
[0085] The amount of filler employed is primarily a function of
weight requirements and distribution.
[0086] Scuff Resistance The scuff resistance test was conducted in
the following manner: a Top-Flite tour pitching wedge (1994) with
box grooves was obtained and was mounted in a Miyamae driving
machine. The club face was oriented for a square hit. The
forward/backward tee position was adjusted so that the tee was four
inches behind the point in the downswing where the club was
vertical. The height of the tee and the toe-heel position of the
club relative to the tee were adjusted in order that the center of
the impact mark was about 3/4 of an inch above the sole and was
centered to the heel across the face. The machine was operated at a
club head speed of 125 feet per second. A minimum of three samples
of each ball were tested. Each ball was hit three times. After
testing, the balls were rated according to the following table:
3 Rating Type of Damage 1 Little or no damage (groove markings or
dents) 2 Small cuts and/or ripples in cover 3 Moderate amount of
material lifted from ball surface, but still attached to ball 4
Material removed or barely attached The balls that were tested were
primed and top coated.
[0087] Cut Resistance
[0088] Cut resistance was measured in accordance with the following
procedure: A golf ball was fired at 135 feet per second against the
leading edge of a 1994 Top-Flite Tour pitching wedge, wherein the
leading edge radius is {fraction (1/32)} inch, the loft angle is 51
degrees, the sole radius is 2.5 inches, and the bounce angle is 7
degrees.
[0089] The cut resistance of the balls tested herein was evaluated
on a scale of 1-5. A 5 represents a cut that extends completely
through the cover to the core; a 4 represents a cut that does not
extend completely through the cover but that does break the
surface; a 3 does not break the surface of the cover but does leave
a permanent dent; a 2 leaves only a slight crease which is
permanent but not as severe as 3; and a 1 represents virtually no
visible indentation or damage of any sort.
[0090] Durability
[0091] Durability is determined by firing a golf ball at 135 ft/sec
(at 72.degree. F.) into 5-sided steel pentagonal container, the
walls of which are steel plates. The container 10, which is shown
schematically in FIG. 1, has a 191/2 inch long insert plate 12
mounted therein, the central portion 14 of which has horizontally
extending square grooves on it which are intended to simulate a
square grooved face of a golf club. The grooves, which are shown in
an exaggerated form in FIG. 2, have a width 30 of 0.033 inches, a
depth 32 of 0.100 inches, and are spaced apart from one another by
land areas 34 having a width of 0.130 inches. The five walls 16 of
the pentagonal container each have a length of 141/2 inches. The
inlet wall is vertical and the insert plate is mounted such that it
inclines upward 30.degree. relative to a horizontal plane away from
opening 20 in container 10. The ball travels 151/2-153/4 inches
horizontally from its point of entry into the container 10 until it
hits the square-grooved central portion 14 of insert plate 12. The
angle between the line of trajectory of the ball and the insert
plate 12 is 30.degree.. The balls are subjected to 70 or more blows
(firings) and are inspected at regular intervals for breakage
(i.e., any signs of cover cracking or delamination). If a
microcrack forms in a ball, its speed will change and the operator
is alerted. The operator then visually inspects the ball. If the
microcrack cannot yet be observed, the ball is returned to the test
until a crack can be visually detected.
[0092] A ball is assigned a Durability Rating according to the
following scale. A sample of twelve balls of the same type are
obtained and are tested using the durability test apparatus
described in the previous paragraph. If less than all of the balls
in the sample survive 70 blows each without cracking, the ball is
assigned a Durability Rating of 1. If all of the balls survive 70
blows and one or two of the twelve balls crack before 100 blows,
the ball is assigned a Durability Rating of 2. If all twelve balls
in the sample survive 100 blows each, but seven or more balls crack
at less than 200 blows each, the ball is assigned a Durability
Rating of 3. If all twelve balls in the sample survive 100 blows
and at least six out of the twelve balls in the sample also survive
200 blows, the balls is assigned a Durability Rating of 4.
[0093] Shore D Hardness As used herein, "Shore D hardness" of a
cover is measured generally in accordance with ASTM D-2240, except
the measurements are made on the curved surface of a molded cover,
rather than on a plaque. Furthermore, the Shore D hardness of the
cover is measured while the cover remains over the core. When a
hardness measurement is made on a dimpled cover, Shore D hardness
is measured at a land area of the dimpled cover.
[0094] Coefficient of Restitution
[0095] The resilience or coefficient of restitution (COR) of a golf
ball is the constant "e," which is the ratio of the relative
velocity of an elastic sphere after direct impact to that before
impact. As a result, the COR ("e") can vary from 0 to 1, with 1
being equivalent to a perfectly or completely elastic collision and
0 being equivalent to a perfectly or completely inelastic
collision.
[0096] COR, along with additional factors such as club head speed,
club head mass, ball weight, ball size and density, spin rate,
angle of trajectory and surface configuration (i.e., dimple pattern
and area of dimple coverage) as well as environmental conditions
(e.g. temperature, moisture, atmospheric pressure, wind, etc.)
generally determine the distance a ball will travel when hit. Along
this line, the distance a golf ball will travel under controlled
environmental conditions is a function of the speed and mass of the
club and size, density and resilience (COR) of the ball and other
factors. The initial velocity of the club, the mass of the club and
the angle of the ball's departure are essentially provided by the
golfer upon striking. Since club head, club head mass, the angle of
trajectory and environmental conditions are not determinants
controllable by golf ball producers and the ball size and weight
are set by the U.S.G.A., these are not factors of concern among
golf ball manufacturers. The factors or determinants of interest
with respect to improved distance are generally the coefficient of
restitution (COR) and the surface configuration (dimple pattern,
ratio of land area to dimple area, etc.) of the ball.
[0097] The COR in solid core balls is a function of the composition
of the molded core and of the cover. The molded core and/or cover
may be comprised of one or more layers such as in multi-layered
balls. In balls containing a wound core (i.e., balls comprising a
liquid or solid center, elastic windings, and a cover), the
coefficient of restitution is a function of not only the
composition of the center and cover, but also the composition and
tension of the elastomeric windings. As in the solid core balls,
the center and cover of a wound core ball may also consist of one
or more layers.
[0098] The coefficient of restitution is the ratio of the outgoing
velocity to the incoming velocity. In the examples of this
application, the coefficient of restitution of a golf ball was
measured by propelling a ball horizontally at a speed of 125.+-.5
feet per second (fps) and corrected to 125 fps against a generally
vertical, hard, flat steel plate and measuring the ball's incoming
and outgoing velocity electronically. Speeds were measured with a
pair of Oehler Mark 55 ballistic screens available from Oehler
Research, Inc., P.O. Box 9135, Austin, Tex. 78766, which provide a
timing puise when an object passes through them. The screens were
separated by 36" and are located 25.25" and 61.25" from the rebound
wall. The ball speed was measured by timing the pulses from screen
1 to screen 2 on the way into the rebound wall (as the average
speed of the ball over 36"), and then the exit speed was timed from
screen 2 to screen 1 over the same distance. The rebound wall was
tilted 2 degrees from a vertical plane to allow the ball to rebound
slightly downward in order to miss the edge of the cannon that
fired it. The rebound wall is solid steel 2.0 inches thick.
[0099] As indicated above, the incoming speed should be 125.+-.5
fps but corrected to 125 fps. The correlation between COR and
forward or incoming speed has been studied and a correction has
been made over the .+-.5 fps range so that the COR is reported as
if the ball had an incoming speed of exactly 125.0 fps.
[0100] The coefficient of restitution must be carefully controlled
in all commercial golf balls if the ball is to be within the
specifications regulated by the United States Golf Association
(U.S.G.A.). As mentioned to some degree above, the U.S.G.A.
standards indicate that a "regulation" ball cannot have an initial
velocity exceeding 255 feet per second in an atmosphere of 75 F.
when tested on a U.S.G.A. machine. Since the coefficient of
restitution of a ball is related to the ball's initial velocity, it
is highly desirable to produce a ball having sufficiently high
coefficient of restitution to closely approach the U.S.G.A. limit
on initial velocity, while having an ample degree of softness
(i.e., hardness) to produce enhanced playability (i.e., spin,
etc.).
[0101] Compression
[0102] PGA compression is another important property involved in
the performance of a golf ball. The compression of the ball can
affect the playability of the ball on striking and the sound or
"click" produced. Similarly, compression can effect the "feel" of
the ball (i.e., hard or soft responsive feel), particularly in
chipping and putting.
[0103] Moreover, while compression itself has little bearing on the
distance performance of a ball, compression can affect the
playability of the ball on striking. The degree of compression of a
ball against the club face and the softness of the cover strongly
influences the resultant spin rate. Typically, a softer cover will
produce a higher spin rate than a harder cover. Additionally, a
harder core will produce a higher spin rate than a softer core.
This is because at impact a hard core serves to compress the cover
of the ball against the face of the club to a much greater degree
than a soft core thereby resulting in more "grab" of the ball on
the clubface and subsequent higher spin rates. In effect the cover
is squeezed between the relatively incompressible core and
clubhead. When a softer core is used, the cover is under much less
compressive stress than when a harder core is used and therefore
does not contact the clubface as intimately. This results in lower
spin rates.
[0104] The term "compression" utilized in the golfball trade
generally defines the overall deflection that a golf ball undergoes
when subjected to a compressive load. For example, PGA compression
indicates the amount of change in golf ball's shape upon striking.
The development of solid core technology in two-piece balls has
allowed for much more precise control of compression in comparison
to thread wound three-piece balls. This is because in the
manufacture of solid core balls, the amount of deflection or
deformation is precisely controlled by the chemical formula used in
making the cores. This differs from wound three-piece balls wherein
compression is controlled in part by the winding process of the
elastic thread. Thus, two-piece and multilayer solid core balls
exhibit much more consistent compression readings than balls having
wound cores such as the thread wound three-piece balls.
[0105] In the past, PGA compression related to a scale of from 0 to
200 given to a golf ball. The lower the PGA compression value, the
softer the feel of the ball upon striking. In practice, tournament
quality balls have compression ratings around 70-110, preferably
around 80 to 100.
[0106] In determining PGA compression using the 0-200 scale, a
standard force is applied to the external surface of the ball. A
ball which exhibits no deflection (0.0 inches in deflection) is
rated 200 and a ball which deflects {fraction (2/10)} the of an
inch (0.2 inches) is rated 0. Every change of 0.001 of an inch in
deflection represents a 1 point drop in compression. Consequently,
a ball which deflects 0.1 inches (100.times.0.001 inches) has a PGA
compression value of 100 (i.e., 200-100) and a ball which deflects
0.110 inches (110.times.0.001 inches) has a PGA compression of 90
(i.e., 200-110).
[0107] In order to assist in the determination of compression,
several devices have been employed by the industry. For example,
PGA compression is determined by an apparatus fashioned in the form
of a small press with an upper and lower anvil. The upper anvil is
at rest against a 200-pound die spring, and the lower anvil is
movable through 0.300 inches by means of a crank mechanism. In its
open position the gap between the anvils is 1.780 inches allowing a
clearance of 0.100 inches for insertion of the ball. As the lower
anvil is raised by the crank, it compresses the ball against the
upper anvil, such compression occurring during the last 0.200
inches of stroke of the lower anvil, the ball then loading the
upper anvil which in turn loads the spring. The equilibrium point
of the upper anvil is measured by a dial micrometer if the anvil is
deflected by the ball more than 0.100 inches (less deflection is
simply regarded as zero compression) and the reading on the
micrometer dial is referred to as the compression of the ball. In
practice, tournament quality balls have compression ratings around
80 to 100 which means that the upper anvil was deflected a total of
0.120 to 0.100 inches.
[0108] An example to determine PGA compression can be shown by
utilizing a golf ball compression tester produced by Atti
Engineering Corporation of Newark, N.J. The value obtained by this
tester relates to an arbitrary value expressed by a number which
may range from 0 to 100, although a value of 200 can be measured as
indicated by two revolutions of the dial indicator on the
apparatus. The value obtained defines the deflection that a golf
ball undergoes when subjected to compressive loading. The Atti test
apparatus consists of a lower movable platform and an upper movable
spring-loaded anvil. The dial indicator is mounted such that it
measures the upward movement of the springloaded anvil. The golf
ball to be tested is placed in the lower platform, which is then
raised a fixed distance. The upper portion of the golf ball comes
in contact with and exerts a pressure on the springloaded anvil.
Depending upon the distance of the golf ball to be compressed, the
upper anvil is forced upward against the spring.
[0109] Alternative devices have also been employed to determine
compression. For example, Applicant also utilizes a modified Riehle
Compression Machine originally produced by Riehle Bros. Testing
Machine Company, Phil., Pa. to evaluate compression of the various
components (i.e., cores, mantle cover balls, finished balls, etc.)
of the golf balls. The Riehle compression device determines
deformation in thousandths of an inch under a fixed initialized
load of 200 pounds. Using such a device, a Riehle compression of 61
corresponds to a deflection under load of 0.061 inches.
[0110] Additionally, an approximate relationship between Riehle
compression and PGA compression exists for balls of the same size.
It has been determined by Applicant that Riehle compression
corresponds to PGA compression by the general formula PGA
compression=160-Riehle compression. Consequently, 80 Riehle
compression corresponds to 80 PGA compression, 70 Riehle
compression corresponds to 90PGA compression, and 60 Riehle
compression corresponds to 100 PGA compression. For reporting
purposes, Applicant's compression values are usually measured as
Riehle compression and converted to PGA compression.
[0111] Furthermore, additional compression devices may also be
utilized to monitor golf ball compression so long as the
correlation to PGA compression is know. These devices have been
designed, such as a Whitney Tester, to correlate or correspond to
PGA compression through a set relationship or formula.
* * * * *