U.S. patent application number 14/670550 was filed with the patent office on 2016-09-29 for golf ball incorporating metallic film and method of making.
This patent application is currently assigned to Acushnet Company. The applicant listed for this patent is Acushnet Company. Invention is credited to Brian Comeau, Matthew F. Hogge, Manjari Kuntimaddi, Peter L. Serdahl.
Application Number | 20160279480 14/670550 |
Document ID | / |
Family ID | 56878456 |
Filed Date | 2016-09-29 |
United States Patent
Application |
20160279480 |
Kind Code |
A1 |
Comeau; Brian ; et
al. |
September 29, 2016 |
GOLF BALL INCORPORATING METALLIC FILM AND METHOD OF MAKING
Abstract
A golf ball of the invention comprises: a substrate layer formed
from at least one of a thermoset or thermoplastic composition and
having an outer surface that is pre-modified with a catalytic
coating; a metallic film that is formed about the outer surface by
contacting the catalytic coating with a mixture comprising: (i) at
least one aqueous and/or organic aerosol comprising at least one
metal in cationic/oxidizing form; and (ii) at least one reducing
agent; and a subsequent layer surrounding the metallic film and
formed from at least one of a thermoset composition or a
thermoplastic composition. Alternatively, the outer surface is not
pre-modified. The subsequent layer may be formed about the metallic
film or in some embodiments may surround a coating layer that is
disposed between the metallic film and the subsequent layer.
Inventors: |
Comeau; Brian; (Berkley,
MA) ; Hogge; Matthew F.; (Plymouth, MA) ;
Kuntimaddi; Manjari; (Raynham, MA) ; Serdahl; Peter
L.; (New Bedford, MA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Acushnet Company |
Fairhaven |
MA |
US |
|
|
Assignee: |
Acushnet Company
Fairhaven
MA
|
Family ID: |
56878456 |
Appl. No.: |
14/670550 |
Filed: |
March 27, 2015 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A63B 37/0039 20130101;
A63B 37/0076 20130101; A63B 37/14 20130101; A63B 37/0033 20130101;
A63B 2209/00 20130101; A63B 37/0045 20130101 |
International
Class: |
A63B 37/00 20060101
A63B037/00 |
Claims
1. A golf ball comprising: a substrate layer formed from at least
one of a thermoset or thermoplastic composition and having an outer
surface that is modified with a catalytic coating; and a metallic
film that is formed about the outer surface by contacting the
catalytic coating with a mixture M.sub.1 comprising: (i) at least
one aqueous and/or organic aerosol comprising at least one metal in
cationic/oxidizing form; and (ii) at least one reducing agent; and
a subsequent layer surrounding the metallic film and formed from at
least one of a thermoset composition or a thermoplastic composition
wherein the catalytic coating is disposed between the metallic film
and the subsequent layer; and wherein interactions at an interface
between the metallic film and each of the substrate layer and the
subsequent layer promote adhesion there between.
2. The golf ball of claim 1, wherein the catalytic coating is
chemisorbed at the outer surface.
3. The golf ball of claim 2, wherein the catalytic coating
comprises a coupling agent selected from titanates, aluminates,
silanes, zirconates, zircoaluminates or mixtures thereof.
4. The golf ball of claim 2, wherein the catalytic coating further
comprises a wetting liquid.
5. The golf ball of claim 4, wherein the wetting liquid is selected
from the group consisting of: deionized water; non-deionized water;
deionized water containing at least one anionic, cationic or
neutral surfactant; non-deionized water containing at least one
anionic, cationic or neutral surfactant; a solution comprising at
least one alcohol; and mixtures thereof.
6. The golf ball of claim 5, wherein the substrate layer is
contacted with the catalytic coating by at least one of: spraying
the catalytic coating onto the outer surface; or dipping the outer
surface in the catalytic coating.
7. The golf ball of claim 1, wherein the metal is selected from the
group consisting of: silver, gold, copper, nickel, zinc, cobalt,
tin, boron, tungsten, and combinations thereof.
8. The golf ball of claim 1, wherein the reducing agent is selected
from the group consisting of: sodium borohydrides, dimethylamine
borane, hydrazine, sodium hypophosphite, formol, lithium aluminium
hydrides, reducing sugars and mixtures thereof.
9. The golf ball of claim 1, wherein the metallic film has a
thickness of from about 0.1 .mu.m to about 50 .mu.m.
10. The golf ball of claim 3, wherein the metallic film is
substantially homogenous.
11. (canceled)
12. (canceled)
13. The golf ball of claim 1, wherein the subsequent layer is
formed from a polyurethane composition.
14. The golf ball of claim 1, wherein a different metallic film is
disposed between the metallic film and the subsequent layer.
15. The golf ball of claim 1, wherein a different metallic film is
disposed between the coating layer and the subsequent layer.
16. The golf ball of claim 1, wherein the substrate layer comprises
a core layer.
17. The golf ball of claim 1, wherein the substrate layer comprises
an intermediate layer.
18. The golf ball of claim 1, wherein the substrate layer comprises
a cover layer.
19. The golf ball of claim 1, wherein the metallic film has a
moisture vapor transmission rate that is lower than a moisture
vapor transmission rate of the subsequent layer.
20. The golf ball of claim 1, wherein the metallic film is an inner
cover layer and is surrounded by an outer cover layer comprising a
polyurethane composition.
21. The golf ball of claim 1, wherein the metallic film has a
moisture vapor transmission rate that is lower than a moisture
vapor transmission rate of the substrate layer.
22. A golf ball comprising: a substrate layer having an outer
surface; and a metallic film that is formed about the outer surface
by contacting the outer surface with a mixture M.sub.2 comprising:
(i) a coupling agent; (ii) at least one aqueous and/or organic
aerosol comprising at least one metal in cationic (oxidizing) form;
and (iii) at least one reducing agent; and a subsequent layer
surrounding the metallic film and formed from at least one of a
thermoset composition or a thermoplastic composition; wherein
interactions at an interface between the metallic film and each of
the substrate layer and subsequent layer promote adhesion.
23. The golf ball of claim 22, wherein the metallic film has a
thickness of from about 0.1 .mu.m to about 50 .mu.m.
24. The golf ball of claim 22, wherein the metallic film is
substantially homogenous.
25. The golf ball of claim 22, wherein the substrate layer is
contacted with mixture M.sub.2 by at least one of: spraying the
mixture onto the outer surface; or dipping the outer surface in
mixture M.sub.2.
26. The golf ball of claim 22, wherein the metallic film has a
moisture vapor transmission rate that is lower than a moisture
vapor transmission rate of the substrate layer.
27. The golf ball of claim 22, wherein the metallic film has a
moisture vapor transmission rate that is lower than a moisture
vapor transmission rate of the subsequent layer.
Description
FIELD OF THE INVENTION
[0001] Durable golf balls exhibiting excellent adhesion between
adjacent layers and being manufacturable simply and cost
effectively, and methods of making such golf balls.
BACKGROUND OF THE INVENTION
[0002] Golf balls are made in a variety of constructions and
compositions. Generally, a core is surrounded by a cover, with at
least one intermediate layer optionally disposed there between.
Examples of conventional golf ball materials range from balata to
polybutadiene, ionomer resins, polyurethanes, and/or polyureas.
Typically, outer layers are formed about the spherical outer
surface of an inner golf ball component via compression molding,
casting, or injection molding.
[0003] Golf ball manufacturers continuously experiment with
constructions and material formulations in order to target and
improve aerodynamic and/or inertial properties and achieve desired
feel without sacrificing durability. In this regard, metallic
layers/films have rarely been incorporated in golf balls despite
their potential advantages such as a barrier to moisture vapor
penetration into inner layers.
[0004] One challenge encountered in previous attempts to
incorporate metallic layers/films in golf ball constructions
relates to achieving sufficient adhesion between the metallic
layer/film and an adjacent layer formed from a thermoset and/or
thermoplastic material. Sufficient adhesion between adjacent layers
improves impact durability and shear resistance, without which both
golf ball appearance and playability commonly suffer.
[0005] Additionally, the manufacturing cost was found to be
undesirably high since the already existing golf ball manufacturing
framework had to be adapted to accommodate processes such as vacuum
metallization, electroplating, and/or sputtering. For at least
these reasons, prior use of metallics in golf balls has been
largely limited to surface paints, pigments, and/or inks.
[0006] However, since metallic layers/films remain an attractive
option for golf ball constructions, there is a need for golf balls
wherein a metallic layer/film may be incorporated about and between
any of the core, intermediate layers and cover layers--without the
aforementioned adhesion problems, and within existing golf ball
manufacturing processes such as chain-on-edge applications. The
present inventive golf ball and methods of making same address and
solve this need.
SUMMARY OF THE INVENTION
[0007] Accordingly, in one embodiment, a golf ball of the invention
comprises: a substrate layer formed from at least one of a
thermoset or thermoplastic composition and having an outer surface
that is pre-modified with a catalytic coating; a metallic film that
is formed about the outer surface by contacting the catalytic
coating with a mixture M.sub.1 comprising: (i) at least one aqueous
and/or organic aerosol comprising at least one metal in
cationic/oxidizing form; and (ii) at least one reducing agent; and
a subsequent layer surrounding the metallic film and formed from at
least one of a thermoset composition or a thermoplastic
composition. The catalytic coating may be chemisorbed at the outer
surface. The catalytic coating may also comprise a coupling agent
selected from titanates, aluminates, silanes, zirconates,
zircoaluminates or mixtures thereof.
[0008] The substrate layer of the golf ball may have the catalytic
coating sprayed onto the outer surface. Alternatively, the
substrate layer may be dipped in the catalytic coating.
[0009] In one embodiment, the catalytic coating may further
comprise a wetting liquid. The wetting liquid may be selected from
the group consisting of: deionized water; non-deionized water;
deionized water containing at least one anionic, cationic or
neutral surfactant; non-deionized water containing at least one
anionic, cationic or neutral surfactant; a solution comprising at
least one alcohol; and mixtures thereof.
[0010] The metal of the metallic film is preferably selected from
the group consisting of: silver, gold, copper, nickel, zinc,
cobalt, tin, boron, tungsten, and combinations thereof. Mixture
M.sub.1 comprises a reducing agent that can be selected from the
group consisting of: sodium borohydrides, dimethylamine borane,
hydrazine, sodium hypophosphite, formol, lithium aluminium
hydrides, reducing sugars and mixtures thereof.
[0011] In a preferred embodiment of the invention, the metallic
film may have a thickness of from about 0.1 .mu.m to about 50
.mu.m. Furthermore, a metallic film may be formed that is
substantially homogenous.
[0012] The metallic film is formed about the outer surface of the
substrate layer and between the substrate layer and subsequent
layer. In one embodiment, a coating layer is disposed between the
metallic film and the subsequent layer. In one embodiment, the
coating layer is a catalytic coating.
[0013] A golf ball of the invention may include multiple metallic
films. For example, a different metallic film may be disposed
between a first metallic film and the subsequent layer. In an
alternative embodiment, the different metallic film may be disposed
between a coating layer and the subsequent layer.
[0014] The substrate layer may comprise any golf ball component
such as a core layer, intermediate layer, a cover layer or even a
coating layer, as long as the resulting golf ball construction is
such that the metallic film is formed about the outer surface of
the substrate layer, and the subsequent layer surrounds the
metallic film. For example, in one preferred embodiment, the
substrate layer comprises a polybutadiene core and the subsequent
layer comprises a polyurethane cover, with the metallic film being
formed about the outer surface of the core and between the core and
cover. In this embodiment, the metallic film may be an intermediate
layer such as an inner cover layer, for example. As used herein,
the term "core" refers to a core having one or more layers. In one
embodiment, the substrate layer and subsequent layer may each
comprise a core layer. Meanwhile, an intermediate layer is any golf
ball layer disposed between the core and an outermost cover layer.
Embodiments are also envisioned wherein the substrate layer and
metallic film are each intermediate layers.
[0015] In still other embodiments, the metallic film is
strategically formed about the substrate layer as a moisture
barrier layer and having a moisture vapor transmission rate that is
lower than that of the substrate layer and/or subsequent layer. In
any of these embodiments, the substrate layer and subsequent layer
may be formed from similar materials or different materials, but
each preferably being formed from at least one of a thermoset or
thermoplastic composition.
[0016] Alternatively, a golf ball of the invention may comprise: a
substrate layer having an outer surface; and a metallic film that
is formed about the outer surface by contacting the outer surface
with a mixture M.sub.2 comprising: (i) a coupling agent; (ii) at
least one aqueous and/or organic aerosol comprising at least one
metal in cationic (oxidizing) form; and (iii) at least one reducing
agent; and a subsequent layer surrounding the metallic film and
formed from at least one of a thermoset composition or a
thermoplastic composition.
[0017] In this embodiment, the first outer surface is not
pre-modified by/with a catalytic coating. Instead, the outer
surface is contacted with the mixture M.sub.2 by at least one of:
spraying the mixture onto the outer surface; or dipping the outer
surface in the mixture M.sub.2.
[0018] Alternatively, the invention is directed to a golf ball
formed from the steps comprising: (a) providing a catalytic
coating; (b) providing: (i) at least one aqueous and/or organic
aerosol comprising at least one metal in cationic/oxidizing form;
and (ii) at least one reducing agent; (c) providing a substrate
layer having a first spherical outer surface; (d) contacting the
outer surface with the catalytic coating and forming a pre-modified
outer surface; (e) contacting the pre-modified outer surface with a
mixture M.sub.1 of (i) the at least one aqueous and/or organic
aerosol comprising at least one metal in cationic/oxidizing form
and the (ii) at least one reducing agent, thereby forming a
metallic film concentrically about the outer surface such that the
substrate layer and the metallic film are bonded at an interface
there between; and forming a subsequent layer about the metallic
film that comprises at least one of a thermoset composition or a
thermoplastic composition.
[0019] In another embodiment, the invention is directed to a golf
ball formed from the steps comprising: (a) providing: (i) at least
one coupling agent; (ii) at least one aqueous and/or organic
aerosol comprising at least one metal in cationic/oxidizing form;
and (iii) at least one reducing agent; (b) providing a substrate
layer having an outer surface; (c) contacting the outer surface
with a mixture M.sub.2 of the (i) at least one coupling agent; (ii)
at least one aqueous and/or organic aerosol comprising at least one
metal in cationic/oxidizing form; and (iii) at least one reducing
agent, and forming a metallic film concentrically about the outer
surface such that the substrate layer and the metallic film are
bonded at an interface there between; and forming a subsequent
layer about the metallic film, the subsequent layer comprising at
least one of a thermoset composition or a thermoplastic
composition.
[0020] The invention is also directed to a method of making the
golf ball comprising: (a) providing a catalytic coating; (b)
providing: (i) at least one aqueous and/or organic aerosol
comprising at least one metal in cationic/oxidizing form; and (ii)
at least one reducing agent; (c) providing a substrate layer having
a first spherical outer surface; (d) contacting the outer surface
with the catalytic coating and forming a pre-modified outer
surface; (e) contacting the pre-modified outer surface with a
mixture M.sub.1 of (i) the at least one aqueous and/or organic
aerosol comprising at least one metal in cationic/oxidizing form
and the (ii) at least one reducing agent, thereby forming a
metallic film concentrically about the outer surface such that the
first layer and the metallic film are bonded at an interface there
between; and forming a subsequent layer about the metallic film,
the subsequent layer comprising at least one of a thermoset
composition or a thermoplastic composition.
[0021] In another embodiment, the method of making the golf ball of
the invention comprises: (a) providing: (i) at least one coupling
agent; (ii) at least one aqueous and/or organic aerosol comprising
at least one metal in cationic/oxidizing form; and (iii) at least
one reducing agent; (b) providing a substrate layer having an outer
surface; (c) contacting the outer surface with a mixture M.sub.2 of
the (i) at least one coupling agent; (ii) at least one aqueous
and/or organic aerosol comprising at least one metal in
cationic/oxidizing form; and (iii) at least one reducing agent, and
forming a metallic film concentrically about the outer surface such
that the substrate layer and the metallic film are bonded at an
interface there between; and forming a subsequent layer about the
metallic film, the subsequent layer comprising at least one of a
thermoset composition or a thermoplastic composition.
DETAILED DESCRIPTION
[0022] A golf ball of the invention cost effectively incorporates a
metallic film which may provide many desirable benefits such as
protection against moisture penetration. In some embodiments of a
golf ball of the invention, the substrate layer is pre-modified
with a catalytic coating that promotes adhesion between the
substrate layer and the metallic film formed thereabout when
mixture M.sub.1 is provided thereabout. In other embodiments, a
coupling agent, for facilitating such adhesion between the
substrate layer and metallic film, is combined into the mixture
M.sub.2 with the (i) at least one aqueous and/or organic aerosol
comprising at least one metal in cationic/oxidizing form; and (ii)
at least one reducing agent. This resulting mixture M.sub.2 is
applied or otherwise provided about or onto the substrate layer,
thereby producing the metallic film.
[0023] Advantageously, in golf balls of the invention, the metallic
film is formed intermediate between an outer golf ball layer and an
inner golf ball layer with excellent adhesion between the inner
layer (substrate layer) and the metallic film as well as between
the metallic film and the outer golf ball layer (the subsequent
layer) surrounding the metallic film. Interactions between the
metallic film and the substrate layer and/or subsequent layer at an
interface there between create sufficient adhesion between the
metallic film and an adjacent layer, thereby producing golf ball
durability when the golf ball is struck by a club head.
[0024] The term "pre-modified", as used herein, shall refer to the
outer surface of the substrate layer being modified with the
catalytic coating at any time prior to the outer surface being
contacted by/with mixture M.sub.1.
[0025] The catalytic coating may further comprise a wetting liquid.
The wetting makes it possible to ensure a homogeneous deposition of
the metallic film, by promoting the mixing of the two active
ingredients (oxidizing agent and reducing agent) sprayed
simultaneously as well as facilitate in spreading the mixture onto
the outer surface.
[0026] The outer surface can also be subjected to a chemical and/or
mechanical treatment. The latter can be by roughening, for example.
Chemical treatments such as standard etching solutions may be used.
The purpose of these treatments is to increase the adherence of the
metallic film onto the outer surface. An activation stage in a
colloidal PdSn solution makes it possible to activate to
saturation.
[0027] Conversion to metal is triggered when mixture M.sub.1 or
mixture M.sub.2 is provided onto the outer surface. The priming or
activation of the reaction may be achieved by any physical
(temperature, UV etc.) or chemical means. The metals can be
advantageously selected, for example, from group VIII of the
periodic table as well as from groups Ib, IIb, Inc, IVa (transition
metals) and VI b of the periodic table. Copper, nickel, zinc,
cobalt, tin, boron, tungsten and alloys thereof, for example. And
different binary and tertiary alloys based on Ni, Co, Zn, Fe, Cu
and B can be produced using a mixture of metal salts. Examples of
alloys include: Ni--B, Ni--B--Zn, Ni--Cu--B, Ni--Co--B, Ni--Fe--B,
Ni--Cu--Co--B, NiSn--B etc.
[0028] Numerous methods are known in the golf ball art for applying
mixture M.sub.1 or mixture M.sub.2 onto the outer surface. Further,
non-limiting methods for forming metallized films onto surfaces
non-electrolytic materials are also set forth in U.S. Pat. No.
8,507,043 of Stremsdoerfer ("'043 Patent"), hereby incorporated by
reference herein in its entirety. The '043 patent teaches surface
depositions that can be produced for the purposes of decoration,
finishing and protection against corrosion (nickel, zinc, Cu,
etc).
[0029] The aerosols sprayed onto outer surface may be obtained from
solutions, advantageously aqueous, of the oxidizing metallic
cation(s) and the reducing agent(s), or from rinsing solutions, or
also if appropriate, from sensitization and/or activation
solutions. The spraying aerosol(s) are generally produced by
nebulization and/or atomization of solution(s) and/or of
dispersion(s), so as to obtain a spray of droplets of an
appropriate size such as less than 100 .mu.m, preferably 60 .mu.m,
and still more preferentially comprised between 0.1 and 50
.mu.m.
[0030] In one embodiment, the mixture of the oxidizing agent(s) and
reducing agent(s) is metastable and, after spraying the mixture,
the latter is activated such that the conversion to metal is
triggered, preferably by bringing into contact with a primer,
advantageously supplied by means of at least one aerosol, before,
during or after the spraying of the mixture. This variant makes it
possible to pre-mix the oxidizing agent and the reducing agent
while slowing down their reaction until they cover the surface of
the substrate after spraying. The priming or activation of the
reaction is then achieved by any physical (temperature, UV etc.) or
chemical means.
[0031] In some embodiments, a coating may be disposed between the
metallic film and subsequent layer. This coating is a catalytic
coating in some embodiments, whereas in other embodiments the
coating may serve as a wetting liquid.
[0032] The subsequent layer may be formed about the metallic layer
by conventional methods extending from at least one of dipping,
soaking, rolling, wiping, spraying, coating, or brushing to at
least one of compression molding, casting, and injection molding,
depending on the material of the subsequent layer to be formed
about the metallic layer.
[0033] Desirably, golf balls of the invention may be made cost
effectively within already existing golf ball manufacturing
framework using conventional processes such as chain-on-edge
applications, which are well known in the golf ball art.
Previously, adaptations had to be made to the already existing golf
ball assembly line in order to accommodate atypical steps,
electrolytic-based methods, for example.
[0034] While not being bound to a particular or specific
conventional golf ball manufacturing assembly set-up, a golf ball
of the invention may be formed, for example, within or along a
conventional golf ball coating booth or line wherein a golf ball
component to be surrounded and bonded with a metallic film may be
engaged, rotated and sprayed or otherwise contacted with the
pre-modification and/or film forming mixtures, followed by curing
and/or top coating, etc.
[0035] In one embodiment, at least one solution of metallic
cation(s) and at least one solution of reducing agent(s) may be
simultaneously sprayed onto the outer surface, in one or more
aerosols, in the same spraying phase. Mixing of the oxidizing
solution with the reducing solution can be carried out just before
the formation of the spraying aerosol or also by merging an aerosol
produced from the oxidizing solution with an aerosol produced from
the reducing solution, preferably, before they come into contact
with the outer surface. In another embodiment, at least one
exclusive oxidizing metal cation spraying phase and at least one
exclusive reducing agent spraying phase are alternated. And several
different oxidizing metallic cations and one or more reducing
agents may be used so as to produce multiple film layers of
different metals or alloys.
[0036] Different binary and tertiary alloys based on Ni, Co, Zn,
Fe, Cu and B can be produced using a mixture of metal salts. The
different salts may be sprayed separately from the reducing agent
but also separately from each other and successively.
[0037] Water is an excellent solvent, without however excluding the
possibility of using organic solvents, for the production of the
solutions from which the sprayed aerosols are produced. The
concentrations of oxidizing metal salt are comprised between 1 g/l
and 60 g/l and preferably between 7 and 30 g/l. The concentrations
of reducing agent are comprised between 0.5 g/1 and 60 g/1 and
preferably between 8 and 20 g/l.
[0038] At least one of the starting solutions may have the
following added to it: at least one natural or synthetic resin or
binding agent, at least one organic or inorganic dye and/or
pigment; at least one brightening agent, preferably selected from
the following products: sulphimides, sulphanamides, sulphonates,
propargyl alcohol, thiourea, mercaptabenzothiazole or mixtures
thereof; at least one surfactant; at least one filler, preferably
selected from the following products: fibres or particles of glass,
carbon, silicon carbide, graphite, diamond, oxides such as alumina,
ceramics, microcapsules, or also calcium or sodium carbonates,
barium sulphates, talc, silicates, in fact any filler capable of
modifying the rheological properties and the mechanical properties
of the metallic films, and the mixtures of these products.
[0039] Numerous other additives may be added, such as in particular
viscosity modifying agents such as ethylene glycol. A fine
adjustment of the viscosity in fact makes it possible to avoid flow
phenomena on the substrate. The reagents therefore remain in
contact with the substrate in the same place for a longer time. It
follows that the mass deposited and therefore the yield of the
oxidation-reduction reaction are improved. On the other hand, the
increase in viscosity improves the dispersion and suspension of the
particles or fibres in the case of the development of a composite
deposition.
[0040] In a golf ball of the invention, the substrate layer and/or
subsequent layer may be formed from conventional thermoset and/or
thermoplastic materials. That being said, a core layer in a golf
ball of the invention may for example be solid, semi-solid,
fluid-filled, or hollow, and may have a single-piece or multi-piece
structure. A variety of materials may be used to make the core
including thermoset compositions such as rubber, styrene butadiene,
polybutadiene, isoprene, polyisoprene, trans-isoprene;
thermoplastics such as ionomer resins, polyamides or polyesters;
and thermoplastic and thermoset polyurethane and polyurea
elastomers. In one embodiment, the core is a single-piece made from
a natural or synthetic rubber composition such as polybutadiene. In
other instances, a two-piece core is constructed; that is, there
may be two core layers. For example, an inner core portion may be
made of a first base rubber material and an outer core layer, which
surrounds the inner core, may be made of a second base rubber
material. The respective core pieces may be made of the same or
different rubber materials. Cross-linking agents and fillers may be
added to the rubber materials.
[0041] More particularly, materials for solid cores typically
include compositions having a base rubber, a filler, an initiator
agent, and a cross-linking agent. The base rubber typically
includes natural or synthetic rubber, such as polybutadiene rubber.
In one embodiment, the base rubber is 1,4-polybutadiene having a
cis-structure of at least 40%. The polybutadiene can be blended
with other elastomers such as natural rubber, polyisoprene rubber,
styrene-butadiene rubber and/or other polybutadienes. Another
suitable rubber that may be used in the core is
trans-polybutadiene. This polybutadiene isomer is formed by
converting the cis-isomer of the polybutadiene to the trans-isomer
during a molding cycle. A soft and fast agent such as
pentachlorothiophenol (PCTP) or ZnPCTP can be blended with the
polybutadiene. These compounds may also function as cis-to-trans
catalyst to convert some cis-1,4 bonds in the polybutadiene into
trans 1,4 bonds.
[0042] Fillers, which may be used to modify such properties as the
specific gravity (density-modifying materials), hardness, weight,
modulus, resiliency, compression, and the like may be added to the
core composition. Normally, the fillers are inorganic, and suitable
fillers include numerous metals or metal oxides, such as zinc oxide
and tin oxide, as well as barium sulfate, zinc sulfate, calcium
carbonate, barium carbonate, clay, tungsten, tungsten carbide,
silica, and mixtures thereof. Fillers may also include various
foaming agents or blowing agents, zinc carbonate, regrind (recycled
core material typically ground to about 30 mesh or less particle
size), high-Mooney-viscosity rubber regrind, and the like. In
addition, polymeric, ceramic, metal, and glass microspheres may be
used.
[0043] In one embodiment, the core is a single-piece core having an
outside diameter of about 1.20 to about 1.65 inches. Preferably,
the single-piece core has a diameter of about 1.62 inches. The core
generally makes up a substantial portion of the ball, for example,
the core may constitute at least about 90% of the ball. Again, the
hardness of the core may vary depending upon the desired properties
of the ball. One non-limiting example of such a construction is as
follows. The core may be a single-piece polybutadiene core having a
diameter of at least about 1.58 inches; the metallic film may have
a thickness of from about 0.1 .mu.m to about 50 .mu.m; and a
polyurethane cover may have a thickness of less than about 0.070
inches. In one particular embodiment, the metallic film is a
moisture barrier layer having a moisture vapor transmission rate
that is lower than the moisture vapor transmission rate of the
polybutadiene core it surrounds, thereby protecting the core from
moisture penetration given that some polyurethane cover materials
may be vulnerable to such. In an alternative embodiment, the
metallic film is a moisture barrier layer having a moisture vapor
transmission rate that is lower than the moisture vapor
transmission rate of the polyurethane cover.
[0044] In another embodiment, the core may include an inner core
portion and surrounding outer core layer. This core structure may
be referred to as a multi-core or two-piece core. The inner core
portion and outer core layer together may be referred to as the
"center" of the ball. In such balls having two-piece cores, the
inner core portion may have a diameter of about 0.75 to about 1.30
inches, more preferably 1.00 to 1.15 inches, and be relatively soft
(that is, it may have a compression of less than about 30.)
Meanwhile, the outer core layer may have a thickness of about 0.20
to about 0.60 inches and be relatively hard (compression of about
70 or greater). That is, the two-piece core or "center" of the
ball, which constitutes the inner core and outer core layer, may
have a total diameter of about 1.50 to about 1.64 inches, more
preferably 1.510 to 1.620 inches, and a compression of about 80 to
about 115, more preferably 85 to 110.
[0045] In one instance, the core is a two-piece core having a total
diameter of about 1.40 inches to about 1.62 inches and comprising
an inner core portion having a diameter of about 0.90 inches to
about 1.20 inches, and an outer core portion having a thickness of
about 0.21 to about 0.36 inches. In such a construction, the
metallic film has a thickness of from about 0.1 .mu.m to about 50
.mu.m, and the cover preferably has a thickness of less than 0.070
inches, preferably less than about 0.040 inches. More preferably,
the cover has a thickness of about 0.015 to 0.040 inches.
[0046] The compression of the core portion is generally overall in
the range of about 40 to about 110 and more preferably in the range
of about 60 to about 100. In general, when the ball contains a
relatively soft core, the resulting spin rate of the ball is
relatively low. The compressive force acting on the ball is less
when a club strikes the ball and compresses the cover against a
relatively soft core. The club face does not fully interface and
grasp the ball's surface and thus the initial spin rate on the ball
is lower. On the other hand, when the ball contains a relatively
hard core, the resulting spin rate of the ball is relatively high.
As the club face strikes the ball, it is able to more fully
interface and grasp the ball's surface and thus the initial spin
rate of the ball is higher. In other embodiments, the overall
coefficient of restitution ("COR") of cores of the present
invention at 125 ft/s is at least 0.750, or at least 0.775 or at
least 0.780, or at least 0.785, or at least 0.790, or at least
0.795, or at least 0.800. Cores are also known to comprise a
variety of other materials that are typically also used for
intermediate and cover layers. Intermediate layers may likewise
also comprise materials generally used in cores and covers as
described herein for example.
[0047] The cover material should impart durability, toughness and
tear-resistance to the ball. For example, polyurethane/polyurea
compositions can be used in the cover layer, because they can
provide the cover with high durability as well as a soft feel. In
other embodiments, the cover may be made of polymers such as
ethylene, propylene, butene-1 or hexane-1 based homopolymers and
copolymers including functional monomers such as acrylic and
methacrylic acid and fully or partially neutralized ionomer resins
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), 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.
[0048] In one embodiment, ionomer resins can be used as the cover
material. These cross-linked polymers contain inter-chain ionic
bonding as well as covalent bonding. The ionomer resins include,
for example, a copolymer of ethylene and an acid group such as
methacrylic or acrylic acid. Metal ions such as sodium, lithium,
zinc, and magnesium are used to neutralize the acid groups in the
polymer. Commercially available ionomer resins are known in the
industry and include numerous resins sold under the trademarks,
Surlyn..RTM.. (DuPont) and Escor..RTM. and Iotek..RTM.. (Exxon).
These ionomer resins are available in various grades and are
identified based on the type of base resin, molecular weight, type
of metal ion, amount of acid, degree of neutralization, additives,
and other properties.
[0049] As discussed above, suitable cover materials include, but
are not limited to, ionomer resins and blends thereof (e.g.,
Surlyn..RTM.. ionomer resins and DuPont..RTM.. HPF 1000 and HPF
2000, commercially available from E. I. du Pont de Nemours and
Company; Iotek..RTM.. ionomers, commercially available from
ExxonMobil Chemical Company; Amplify..RTM.. IO ionomers of ethylene
acrylic acid copolymers, commercially available from The Dow
Chemical Company; and Clarix..RTM.. ionomer resins, commercially
available from A. Schulman Inc.); polyurethanes; polyureas;
copolymers and hybrids of polyurethane and polyurea; polyethylene,
including, for example, low density polyethylene, linear low
density polyethylene, and high density polyethylene; polypropylene;
rubber-toughened olefin polymers; acid copolymers, e.g.,
(meth)acrylic acid, which do not become part of an ionomeric
copolymer; plastomers; flexomers; styrene/butadiene/styrene block
copolymers; styrene/ethylene-butylene/styrene block copolymers;
dynamically vulcanized elastomers; ethylene vinyl acetates;
ethylene methyl acrylates; polyvinyl chloride resins; polyamides,
amide-ester elastomers, and graft copolymers of ionomer and
polyamide, including, for example, Pebax..RTM.. thermoplastic
polyether block amides, commercially available from Arkema Inc;
crosslinked trans-polyisoprene and blends thereof; polyester-based
thermoplastic elastomers, such as Hytrel..RTM.., commercially
available from E. I. du Pont de Nemours and Company;
polyurethane-based thermoplastic elastomers, such as
Elastollan..RTM.., commercially available from BASF; synthetic or
natural vulcanized rubber; and combinations thereof. In a
particular embodiment, the cover is a single layer formed from a
composition selected from the group consisting of ionomers,
polyester elastomers, polyamide elastomers, and combinations of two
or more thereof.
[0050] In a second embodiment, the cover may comprise a composition
formed from a thermoplastic polyurethane, thermoset polyurethane,
thermoplastic polyurea, or thermoset polyurea. More particularly, a
polyurea composition can be used as the cover layer. In another
version, the cover layer comprises a blend of from about 10% to
about 90% by weight of the polyurea composition and from about 90%
to about 10% of a polyurethane composition. In yet another
embodiment, the cover layer comprises a blend of from about 10% to
about 90% by weight of the polyurea composition and from about 90%
to about 10% of another polymer or other material such as vinyl
resins, polyesters, polyamides, and polyolefins.
[0051] Polyurethanes, polyureas, and blends and hybrids of
polyurethane/polyurea are also particularly suitable for forming
cover layers. When used as cover layer materials, polyurethanes and
polyureas can be thermoset or thermoplastic. Thermoset materials
can be formed into golf ball layers by conventional casting or
reaction injection molding techniques. Thermoplastic materials can
be formed into golf ball layers by conventional compression or
injection molding techniques.
[0052] Polyurethane cover compositions that can be used include
those formed from the reaction product of at least one
polyisocyanate and at least one curing agent. The curing agent can
include, for example, one or more diamines, one or more polyols, or
a combination thereof. The at least one polyisocyanate can be
combined with one or more polyols to form a prepolymer, which is
then combined with the at least one curing agent. Thus, when
polyols are described herein they may be suitable for use in one or
both components of the polyurethane material, that is, as part of a
prepolymer and in the curing agent. The curing agent includes a
polyol curing agent preferably selected from the group consisting
of ethylene glycol; diethylene glycol;
[0053] polyethylene glycol; propylene glycol; polypropylene glycol;
lower molecular weight polytetramethylene ether glycol;
1,3-bis(2-hydroxyethoxy)benzene;
1,3-bis-[2-(2-hydroxyethoxy)ethoxy]benzene;
1,3-bis-{2-[2-(2-hydroxyethoxy)ethoxy]ethoxy}benzene;
1,4-butanediol; 1,5-pentanediol; 1,6-hexanediol;
resorcinol-di-(.beta.-hydroxyethyl)ether;
hydroquinone-di-(.beta.-hydroxyethyl)ether; trimethylol propane;
and combinations thereof.
[0054] Suitable polyurethane cover compositions also include those
formed from the reaction product of at least one isocyanate and at
least one curing agent or the reaction product of at least one
isocyanate, at least one polyol, and at least one curing agent.
Preferred isocyanates include those selected from the group
consisting of 4,4'-diphenylmethane diisocyanate, polymeric
4,4'-diphenylmethane diisocyanate, carbodiimide-modified liquid
4,4'-diphenylmethane diisocyanate, 4,4'-dicyclohexylmethane
diisocyanate, p-phenylene diisocyanate, toluene diisocyanate,
isophoronediisocyanate, p-methylxylene diisocyanate, m-methylxylene
diisocyanate, o-methylxylene diisocyanate, and combinations
thereof. Preferred polyols include those selected from the group
consisting of polyether polyol, hydroxy-terminated polybutadiene,
polyester polyol, polycaprolactone polyol, polycarbonate polyol,
and combinations thereof. Preferred curing agents include polyamine
curing agents, polyol curing agents, and combinations thereof.
Polyamine curing agents are particularly preferred. Preferred
polyamine curing agents include, for example,
3,5-dimethylthio-2,4-toluenediamine, or an isomer thereof;
3,5-diethyltoluene-2,4-diamine, or an isomer thereof;
4,4'-bis-(sec-butylamino)-diphenylmethane;
1,4-bis-(sec-butylamino)-benzene,
4,4'-methylene-bis-(2-chloroaniline);
4,4'-methylene-bis-(3-chloro-2,6-diethylaniline); trimethylene
glycol-di-p-aminobenzoate;
polytetramethyleneoxide-di-p-aminobenzoate; N,N'-dialkyldiamino
diphenyl methane; p,p'-methylene dianiline; phenylenediamine;
4,4'-methylene-bis-(2-chloroaniline);
4,4'-methylene-bis-(2,6-diethylaniline);
4,4'-diamino-3,3'-diethyl-5,5'-dimethyl diphenylmethane;
2,2',3,3'-tetrachloro diamino diphenylmethane;
4,4'-methylene-bis-(3-chloro-2,6-diethylaniline); and combinations
thereof.
[0055] The cover composition is not limited by the use of a
particular polyisocyanate. Suitable polyisocyanates include, but
are not limited to, 4,4'-diphenylmethane diisocyanate ("MDI"),
polymeric MDI, carbodiimide-modified liquid MDI,
4,4'-dicyclohexylmethane diisocyanate ("H.sub.12MDI"), p-phenylene
diisocyanate ("PPDI"), toluene diisocyanate ("TDI"),
3,3'-dimethyl-4,4'-biphenylene diisocyanate ("TODI"),
isophoronediisocyanate ("IPDI"), hexamethylene diisocyanate
("HDI"), naphthalene diisocyanate ("NDI"); xylene diisocyanate
("XDI"); para-tetramethylxylene diisocyanate ("p-TMXDI");
meta-tetramethylxylene diisocyanate ("m-TMXDI"); ethylene
diisocyanate; propylene-1,2-diisocyanate;
tetramethylene-1,4-diisocyanate; cyclohexyl diisocyanate;
1,6-hexamethylene-diisocyanate ("HDI"); dodecane-1,12-diisocyanate;
cyclobutane-1,3-diisocyanate; cyclohexane-1,3-diisocyanate;
cyclohexane-1,4-diisocyanate;
1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane; methyl
cyclohexylene diisocyanate; triisocyanate of HDI; triisocyanate of
2,4,4-trimethyl-1,6-hexane diisocyanate ("TMDI"), tetracene
diisocyanate, naphthalene diisocyanate, anthracene diisocyanate;
and combinations thereof. Polyisocyanates are known to those of
ordinary skill in the art as having more than one isocyanate group,
e.g., di-, tri-, and tetra-isocyanate. Preferably, the
polyisocyanate is selected from MDI, PPDI, TDI, and combinations
thereof. More preferably, the polyisocyanate includes MDI. It
should be understood that, as used herein, the term "MDI" includes
4,4'-diphenylmethane diisocyanate, polymeric MDI,
carbodiimide-modified liquid MDI, combinations thereof and,
additionally, that the diisocyanate employed may be "low free
monomer," understood by one of ordinary skill in the art to have
lower levels of "free" monomer isocyanate groups than conventional
diisocyanates, i.e., the compositions of the invention typically
have less than about 0.1% free monomer groups. Examples of "low
free monomer" diisocyanates include, but are not limited to Low
Free Monomer MDI, Low Free Monomer TDI, and Low Free Monomer
PPDI.
[0056] The at least one polyisocyanate may have less than 14%
unreacted NCO groups. Preferably, the at least one polyisocyanate
has no greater than 8.5% NCO, more preferably from 2.5% to 8.0%, or
from 4.0% to 7.2%, or from 5.0% to 6.5%.
[0057] The cover composition is not limited by the use of a
particular polyol. In one embodiment, the molecular weight of the
polyol is from about 200 to about 6000. Exemplary polyols include,
but are not limited to, polyether polyols, hydroxy-terminated
polybutadiene (including partially/fully hydrogenated derivatives),
polyester polyols, polycaprolactone polyols, and polycarbonate
polyols. Particularly preferred are polytetramethylene ether glycol
("PTMEG"), polyethylene propylene glycol, polyoxypropylene glycol,
and combinations thereof. The hydrocarbon chain can have saturated
or unsaturated bonds and substituted or unsubstituted aromatic and
cyclic groups. Preferably, the polyol includes PTMEG. Suitable
polyester polyols include, but are not limited to, polyethylene
adipate glycol, polybutylene adipate glycol, polyethylene propylene
adipate glycol, ortho-phthalate-1,6-hexanediol, and combinations
thereof. The hydrocarbon chain can have saturated or unsaturated
bonds, or substituted or unsubstituted aromatic and cyclic groups.
Suitable polycaprolactone polyols include, but are not limited to
1,6-hexanediol-initiated polycaprolactone, diethylene glycol
initiated polycaprolactone, trimethylol propane initiated
polycaprolactone, neopentyl glycol initiated polycaprolactone,
1,4-butanediol-initiated polycaprolactone, and combinations
thereof. The hydrocarbon chain can have saturated or unsaturated
bonds, or substituted or unsubstituted aromatic and cyclic groups.
Suitable polycarbonates include, but are not limited to,
polyphthalate carbonate. The hydrocarbon chain can have saturated
or unsaturated bonds, or substituted or unsubstituted aromatic and
cyclic groups.
[0058] Polyamine curatives are also suitable for use in the curing
agent of polyurethane compositions and have been found to improve
cut, shear, and impact resistance of the resultant balls. Preferred
polyamine curatives include, but are not limited to
3,5-dimethylthio-2,4-toluenediamine and isomers thereof;
3,5-diethyltoluene-2,4-diamine and isomers thereof, such as
3,5-diethyltoluene-2,6-diamine;
4,4'-bis-(sec-butylamino)-diphenylmethane;
1,4-bis-(sec-butylamino)-benzene,
4,4'-methylene-bis-(2-chloroaniline);
4,4'-methylene-bis-(3-chloro-2,6-diethylaniline);
polytetramethyleneoxide-di-p-aminobenzoate; N,N'-dialkyldiamino
diphenyl methane; p,p'-methylene dianiline ("MDA");
m-phenylenediamine ("MPDA"); 4,4'-methylene-bis-(2-chloroaniline)
("MOCA"); 4,4'-methylene-bis-(2,6-diethylaniline);
4,4'-diamino-3,3'-diethyl-5,5'-dimethyl diphenylmethane;
2,2',3,3'-tetrachloro diamino diphenylmethane;
4,4'-methylene-bis-(3-chloro-2,6-diethylaniline); trimethylene
glycol di-p-aminobenzoate; and combinations thereof. Preferably,
the curing agent includes 3,5-dimethylthio-2,4-toluenediamine and
isomers thereof, such as ETHACURE 300. Suitable polyamine
curatives, which include both primary and secondary amines,
preferably have weight average molecular weights ranging from about
64 to about 2000.
[0059] At least one of a diol, triol, tetraol, or
hydroxy-terminated curative may be added to the polyurethane
composition. Suitable diol, triol, and tetraol groups include
ethylene glycol; diethylene glycol; polyethylene glycol; propylene
glycol; polypropylene glycol; lower molecular weight
polytetramethylene ether glycol; 1,3-bis(2-hydroxyethoxy)benzene;
1,3-bis-[2-(2-hydroxyethoxy)ethoxy]benzene;
1,3-bis-{2-[2-(2-hydroxyethoxy) ethoxy] ethoxy }benzene;
1,4-butanediol; 1,5-pentanediol; 1,6-hexanediol;
resorcinol-di-(4-hydroxyethyl)ether;
hydroquinone-di-(4-hydroxyethyl)ether; and combinations thereof.
Preferred hydroxy-terminated curatives include ethylene glycol;
diethylene glycol; 1,4-butanediol; 1,5-pentanediol; 1,6-hexanediol,
trimethylol propane, and combinations thereof. Preferably, the
hydroxy-terminated curative has a molecular weights ranging from
about 48 to 2000. It should be understood that molecular weight, as
used herein, is the absolute weight average molecular weight and
would be understood as such by one of ordinary skill in the
art.
[0060] Both the hydroxy-terminated and amine curatives can include
one or more saturated, unsaturated, aromatic, and cyclic groups.
Additionally, the hydroxy-terminated and amine curatives can
include one or more halogen groups. The polyurethane composition
can be formed with a blend or mixture of curing agents. If desired,
however, the polyurethane composition may be formed with a single
curing agent.
[0061] Any method known to one of ordinary skill in the art may be
used to combine the polyisocyanate, polyol, and curing agent. One
commonly employed method, known in the art as a one-shot method,
involves concurrent mixing of the polyisocyanate, polyol, and
curing agent.
[0062] This method results in a mixture that is inhomogeneous (more
random) and affords the manufacturer less control over the
molecular structure of the resultant composition. A preferred
method of mixing is known as a pre-polymer method. In this method,
the polyisocyanate and the polyol are mixed separately prior to
addition of the curing agent. This method affords a more
homogeneous mixture resulting in a more consistent polymer
composition.
[0063] Suitable polyurethanes are further disclosed, for example,
in U.S. Pat. Nos. 5,334,673, 6,506,851, 6,756,436, 6,867,279,
6,960,630, and 7,105,623, the entire disclosures of which are
hereby incorporated herein by reference. Suitable polyureas are
further disclosed, for example, in U.S. Pat. Nos. 5,484,870 and
6,835,794, and U.S. Patent Application No. 60/401,047, the entire
disclosures of which are hereby incorporated herein by reference.
Suitable polyurethane-urea cover materials include
polyurethane/polyurea blends and copolymers comprising urethane and
urea segments, as disclosed in U.S. Patent Application Publication
No. 2007/0117923, the entire disclosure of which is hereby
incorporated herein by reference.
[0064] Cover compositions may also include one or more filler(s),
such as coloring agents, fluorescent agents, whitening agents,
antioxidants, dispersants, UV absorbers, light stabilizers,
plasticizers, surfactants, compatibility agents, foaming agents,
reinforcing agents, release agents, and the like.
[0065] Suitable cover materials and constructions also include, but
are not limited to, those disclosed in U.S. Patent Application
Publication No. 2005/0164810, U.S. Pat. Nos. 5,919,100, 6,117,025,
6,767,940, and 6,960,630, and PCT Publications WO00/23519 and
WO00/29129, the entire disclosures of which are hereby incorporated
herein by reference.
[0066] The golf ball of this invention may have single-, dual-, or
multi-layered covers preferably having an overall thickness within
a range having a lower limit of 0.010 or 0.020 or 0.025 or 0.030 or
0.040 or 0.045 inches and an upper limit of 0.050 or 0.060 or 0.070
or 0.075 or 0.080 or 0.090 or 0.100 or 0.150 or 0.200 or 0.300 or
0.500 inches. In one embodiment, the cover is a single layer having
a thickness of from 0.025 inches to 0.035 inches. Again, the cover
hardness may be targeted depending on desired playing
characteristics. As a general rule, all other things being equal, a
golf ball having a relatively soft cover will spin more than a
similarly constructed ball having a harder cover.
[0067] In the present invention, "compression" is measured
according to a known procedure, using an Atti compression test
device, wherein a piston is used to compress a ball against a
spring. The travel of the piston is fixed and the deflection of the
spring is measured. The measurement of the deflection of the spring
does not begin with its contact with the ball; rather, there is an
offset of approximately the first 1.25 mm (0.05 inches) of the
spring's deflection.
[0068] Cores having a very low stiffness will not cause the spring
to deflect by more than 1.25 mm and therefore have a zero
compression measurement. The Atti compression tester is designed to
measure objects having a diameter of 1.680 inches; thus, smaller
objects, such as golf ball cores, must be shimmed to a total height
of 1.680 inches to obtain an accurate reading. Conversion from Atti
compression to Riehle (cores), Riehle (balls), 100 kg deflection,
130-10 kg deflection or effective modulus can be carried out
according to the formulas given in J. Dalton.
[0069] In a golf ball if the invention, Coefficient of Restitution
or COR is determined according to a known procedure, wherein a golf
ball or golf ball subassembly (for example, a golf ball core) is
fired from an air cannon at two given velocities and a velocity of
125 ft/s is used for the calculations. Ballistic light screens are
located between the air cannon and steel plate at a fixed distance
to measure ball velocity. As the ball travels toward the steel
plate, it activates each light screen and the ball's time period at
each light screen is measured. This provides an incoming transit
time period which is inversely proportional to the ball's incoming
velocity. The ball makes impact with the steel plate and rebounds
so it passes again through the light screens. As the rebounding
ball activates each light screen, the ball's time period at each
screen is measured. This provides an outgoing transit time period
which is inversely proportional to the ball's outgoing velocity.
COR is then calculated as the ratio of the outgoing transit time
period to the incoming transit time period,
COR=V.sub.out/V.sub.in=T.sub.in/T.sub.out. The COR value can be
targeted, for example, by varying the core peroxide and antioxidant
types and amounts as well as the cure temperature and duration.
[0070] The surface hardness of a golf ball layer is obtained from
the average of a number of measurements taken from opposing
hemispheres, taking care to avoid making measurements on the
parting line of the core or on surface defects such as holes or
protrusions. Hardness measurements are made pursuant to ASTM D-2240
"Indentation Hardness of Rubber and Plastic by Means of a
Durometer." Because of the curved surface of the golf ball layer,
care must be taken to ensure that the golf ball or golf ball
subassembly is centered under the durometer indentor before a
surface hardness reading is obtained. A calibrated digital
durometer, capable of reading to 0.1 hardness units, is used for
all hardness measurements. The digital durometer must be attached
to and its foot made parallel to the base of an automatic stand.
The weight on the durometer and attack rate conforms to ASTM
D-2240. It should be understood that there is a fundamental
difference between "material hardness" and "hardness as measured
directly on a golf ball." For purposes of the present invention,
material hardness is measured according to ASTM D2240 and generally
involves measuring the hardness of a flat "slab" or "button" formed
of the material. Surface hardness as measured directly on a golf
ball (or other spherical surface) typically results in a different
hardness value. The difference in "surface hardness" and "material
hardness" values is due to several factors including, but not
limited to, ball construction (that is, core type, number of cores
and/or cover layers, and the like); ball (or sphere) diameter; and
the material composition of adjacent layers. It also should be
understood that the two measurement techniques are not linearly
related and, therefore, one hardness value cannot easily be
correlated to the other.
[0071] It is understood that the golf balls of the invention
incorporating at least one metallic film as described and
illustrated herein represent only some of the many embodiments of
the invention. It is appreciated by those skilled in the art that
various changes and additions can be made to such golf balls
without departing from the spirit and scope of this invention. It
is intended that all such embodiments be covered by the appended
claims.
[0072] A golf ball of the invention may further incorporate
indicia, which as used herein, is considered to mean any symbol,
letter, group of letters, design, or the like, that can be added to
the dimpled surface of a golf ball.
[0073] It will be appreciated that any known dimple pattern may be
used with any number of dimples having any shape or size. For
example, the number of dimples may be 252 to 456, or 330 to 392 and
may comprise any width, depth, and edge angle. The parting line
configuration of said pattern may be either a straight line or a
staggered wave parting line (SWPL), for example.
[0074] In any of these embodiments the single-layer core may be
replaced with a two or more layer core wherein at least one core
layer has a hardness gradient.
[0075] Other than in the operating examples, or unless otherwise
expressly specified, all of the numerical ranges, amounts, values
and percentages such as those for amounts of materials and others
in the specification may be read as if prefaced by the word "about"
even though the term "about" may not expressly appear with the
value, amount or range. Accordingly, unless indicated to the
contrary, the numerical parameters set forth in the specification
and attached claims are approximations that may vary depending upon
the desired properties sought to be obtained by the present
invention. At the very least, and not as an attempt to limit the
application of the doctrine of equivalents to the scope of the
claims, each numerical parameter should at least be construed in
light of the number of reported significant digits and by applying
ordinary rounding techniques.
[0076] Notwithstanding that the numerical ranges and parameters
setting forth the broad scope of the invention are approximations,
the numerical values set forth in the specific examples are
reported as precisely as possible. Any numerical value, however,
inherently contain certain errors necessarily resulting from the
standard deviation found in their respective testing measurements.
Furthermore, when numerical ranges of varying scope are set forth
herein, it is contemplated that any combination of these values
inclusive of the recited values may be used.
[0077] Although the golf ball of the invention has been described
herein with reference to particular means and materials, it is to
be understood that the invention is not limited to the particulars
disclosed and extends to all equivalents within the scope of the
claims.
* * * * *