U.S. patent application number 14/145616 was filed with the patent office on 2014-04-24 for golf balls having dual-layer cores with metal-containing centers.
This patent application is currently assigned to Acushnet Company. The applicant listed for this patent is Acushnet Company. Invention is credited to Mark L. Binette, Robert Blink, David A. Bulpett, Brian Comeau, Michael J. Sullivan.
Application Number | 20140113749 14/145616 |
Document ID | / |
Family ID | 50485833 |
Filed Date | 2014-04-24 |
United States Patent
Application |
20140113749 |
Kind Code |
A1 |
Sullivan; Michael J. ; et
al. |
April 24, 2014 |
GOLF BALLS HAVING DUAL-LAYER CORES WITH METAL-CONTAINING
CENTERS
Abstract
Multi-piece golf balls containing a dual-core structure are
provided. The core structure includes a small, heavy inner core
(center) having a relatively high specific gravity and a
surrounding outer core layer having a relatively low specific
gravity. The core structure may have different hardness gradients.
The center of the core comprises a metal material such as copper,
steel, brass, tungsten, titanium, aluminum, and alloys thereof. The
outer core layer is formed from a thermoset composition, such as
polybutadiene rubber, or from a thermoplastic composition, such as
an ethylene acid copolymer ionomer resin.
Inventors: |
Sullivan; Michael J.; (Old
Lyme, CT) ; Bulpett; David A.; (Boston, MA) ;
Blink; Robert; (Newport, RI) ; Binette; Mark L.;
(Mattapoisett, MA) ; Comeau; Brian; (Berkley,
MA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Acushnet Company |
Fairhaven |
MA |
US |
|
|
Assignee: |
Acushnet Company
Fairhaven
MA
|
Family ID: |
50485833 |
Appl. No.: |
14/145616 |
Filed: |
December 31, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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13606099 |
Sep 7, 2012 |
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14145616 |
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13611376 |
Sep 12, 2012 |
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13606099 |
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Current U.S.
Class: |
473/373 |
Current CPC
Class: |
A63B 37/0075 20130101;
A63B 37/0051 20130101; A63B 37/0066 20130101; A63B 37/0047
20130101; A63B 37/0044 20130101; A63B 37/0045 20130101; A63B
37/0076 20130101; A63B 37/0022 20130101; A63B 37/0091 20130101;
A63B 37/0043 20130101; A63B 37/0064 20130101; A63B 37/0058
20130101; A63B 37/0092 20130101; A63B 37/0039 20130101; A63B 45/00
20130101; A63B 37/0054 20130101 |
Class at
Publication: |
473/373 |
International
Class: |
A63B 37/00 20060101
A63B037/00 |
Claims
1. A golf ball having a multi-layered core, comprising: i) an inner
core having a diameter of from 0.100 inches to 1.100 inches and
formed from a metal material dispersed in a polymer matrix, wherein
the polymer matrix is a highly neutralized polymer composition
comprising: an acid copolymer of ethylene and an
.alpha.,.beta.-unsaturated carboxylic acid, optionally including a
softening monomer selected from the group consisting of alkyl
acrylates and methacrylates; a non-acid polymer selected from the
group consisting of polyolefins, polyamides, polyesters,
polyethers, polyurethanes, metallocene-catalyzed polymers,
single-site catalyst polymerized polymers, ethylene propylene
rubber, ethylene propylene diene rubber, styrenic block copolymer
rubbers, alkyl acrylate rubbers, and functionalized derivatives
thereof; an organic acid or salt thereof; and a cation source
present in an amount sufficient to neutralize greater than 80% of
all acid groups present in the composition; ii) an outer core layer
disposed about the inner core, the outer core layer being formed
from a thermoset material and having a thickness of from 0.200
inches to 1.200 inches, an outer surface of from 40 Shore D to 85
Shore D, an inner surface hardness of from 42 Shore D to 87 Shore
D, and a zero or negative hardness gradient; and iii) a cover
having at least one layer disposed about the multi-layered core;
and wherein the specific gravity of the inner core is greater than
the specific gravity of the outer core layer.
2. The golf ball of claim 1, wherein the acid copolymer of ethylene
and an .alpha.,.beta.-unsaturated carboxylic acid does not include
a softening monomer, the non-acid polymer is an alkyl acrylate
rubber selected from ethylene-alkyl acrylates and ethylene-alkyl
methacrylates, and the organic acid salt is magnesium oleate
present in an amount of 20 parts or greater per 100 parts of acid
copolymer and non-acid copolymer combined.
3. The golf ball of claim 1, wherein the cation source is present
in an amount sufficient to neutralize 110% or greater of all acid
groups present in the composition.
4. A golf ball having a multi-layered core, comprising: i) an inner
core having a diameter of from 0.100 inches to 1.100 inches and
formed from a metal material dispersed in a polymer matrix, wherein
the polymer matrix is a highly neutralized polymer composition
comprising: an acid copolymer of ethylene and an
.alpha.,.beta.-unsaturated carboxylic acid, optionally including a
softening monomer selected from the group consisting of alkyl
acrylates and methacrylates; a non-acid polymer selected from the
group consisting of polyolefins, polyamides, polyesters,
polyethers, polyurethanes, metallocene-catalyzed polymers,
single-site catalyst polymerized polymers, ethylene propylene
rubber, ethylene propylene diene rubber, styrenic block copolymer
rubbers, alkyl acrylate rubbers, and functionalized derivatives
thereof; an organic acid or salt thereof; and a cation source
present in an amount sufficient to neutralize greater than 80% of
all acid groups present in the composition; ii) an outer core layer
disposed about the inner core, the outer core layer being formed
from a thermoset material and having a thickness of from 0.200
inches to 1.200 inches, an outer surface of from 43 Shore D to 88
Shore D, and an inner surface hardness of from 40 Shore D to 85
Shore D, and a positive hardness gradient; and iii) a cover having
at least one layer disposed about the multi-layered core; and
wherein the specific gravity of the inner core is greater than the
specific gravity of the outer core layer.
5. The golf ball of claim 4, wherein the acid copolymer of ethylene
and an .alpha.,.beta.-unsaturated carboxylic acid does not include
a softening monomer, the non-acid polymer is an alkyl acrylate
rubber selected from ethylene-alkyl acrylates and ethylene-alkyl
methacrylates, and the organic acid salt is magnesium oleate
present in an amount of 20 parts or greater per 100 parts of acid
copolymer and non-acid copolymer combined.
6. The golf ball of claim 4, wherein the cation source is present
in an amount sufficient to neutralize 110% or greater of all acid
groups present in the composition.
7. A golf ball having a multi-layered core, comprising: i) an inner
core having a diameter of from 0.100 inches to 1.100 inches, a
positive hardness gradient, and formed from a metal material
dispersed in a thermoset polymeric matrix; ii) an outer core layer
disposed about the inner core, the outer core layer having a
thickness of from 0.200 inches to 1.200 inches and formed from a
highly neutralized polymer composition comprising: an acid
copolymer of ethylene and an .alpha.,.beta.-unsaturated carboxylic
acid, optionally including a softening monomer selected from the
group consisting of alkyl acrylates and methacrylates; a non-acid
polymer selected from the group consisting of polyolefins,
polyamides, polyesters, polyethers, polyurethanes,
metallocene-catalyzed polymers, single-site catalyst polymerized
polymers, ethylene propylene rubber, ethylene propylene diene
rubber, styrenic block copolymer rubbers, alkyl acrylate rubbers,
and functionalized derivatives thereof; an organic acid or salt
thereof; and a cation source present in an amount sufficient to
neutralize greater than 80% of all acid groups present in the
composition; and iii) a cover having at least one layer disposed
about the multi-layered core; wherein the specific gravity of the
inner core is greater than the specific gravity of the outer core
layer.
8. The golf ball of claim 7, wherein the acid copolymer of ethylene
and an .alpha.,.beta.-unsaturated carboxylic acid does not include
a softening monomer, the non-acid polymer is an alkyl acrylate
rubber selected from ethylene-alkyl acrylates and ethylene-alkyl
methacrylates, and the organic acid salt is magnesium oleate
present in an amount of 20 parts or greater per 100 parts of acid
copolymer and non-acid copolymer combined.
9. The golf ball of claim 7, wherein the cation source is present
in an amount sufficient to neutralize 110% or greater of all acid
groups present in the composition.
10. A golf ball having a multi-layered core, comprising: i) an
inner core having a diameter of from 0.100 inches to 1.100 inches,
a zero or negative hardness gradient, and formed from a metal
material dispersed in a thermoset polymeric matrix; ii) an outer
core layer disposed about the inner core, the outer core layer
having a thickness of from 0.200 inches to 1.200 inches and formed
from a highly neutralized polymer composition comprising: an acid
copolymer of ethylene and an .alpha.,.beta.-unsaturated carboxylic
acid, optionally including a softening monomer selected from the
group consisting of alkyl acrylates and methacrylates; a non-acid
polymer selected from the group consisting of polyolefins,
polyamides, polyesters, polyethers, polyurethanes,
metallocene-catalyzed polymers, single-site catalyst polymerized
polymers, ethylene propylene rubber, ethylene propylene diene
rubber, styrenic block copolymer rubbers, alkyl acrylate rubbers,
and functionalized derivatives thereof; an organic acid or salt
thereof; and a cation source present in an amount sufficient to
neutralize greater than 80% of all acid groups present in the
composition; and iii) a cover having at least one layer disposed
about the multi-layered core; wherein the specific gravity of the
inner core is greater than the specific gravity of the outer core
layer.
11. The golf ball of claim 10, wherein the acid copolymer of
ethylene and an .alpha.,.beta.-unsaturated carboxylic acid does not
include a softening monomer, the non-acid polymer is an alkyl
acrylate rubber selected from ethylene-alkyl acrylates and
ethylene-alkyl methacrylates, and the organic acid salt is
magnesium oleate present in an amount of 20 parts or greater per
100 parts of acid copolymer and non-acid copolymer combined.
12. The golf ball of claim 10, wherein the cation source is present
in an amount sufficient to neutralize 110% or greater of all acid
groups present in the composition.
13. A golf ball having a multi-layered core, comprising: i) an
inner core having a diameter of from 0.100 inches to 1.100 inches
and formed from a metal material dispersed in a polymer matrix,
wherein the polymer matrix is a first highly neutralized polymer
composition; ii) an outer core layer disposed about the inner core,
the outer core layer having a thickness of from 0.200 inches to
1.200 inches and formed from a second highly neutralized polymer
composition; and iii) a cover having at least one layer disposed
about the multi-layered core; wherein at least one of the first
highly neutralized polymer composition and the second highly
neutralized polymer composition comprises: an acid copolymer of
ethylene and an .alpha.,.beta.-unsaturated carboxylic acid,
optionally including a softening monomer selected from the group
consisting of alkyl acrylates and methacrylates; a non-acid polymer
selected from the group consisting of polyolefins, polyamides,
polyesters, polyethers, polyurethanes, metallocene-catalyzed
polymers, single-site catalyst polymerized polymers, ethylene
propylene rubber, ethylene propylene diene rubber, styrenic block
copolymer rubbers, alkyl acrylate rubbers, and functionalized
derivatives thereof; an organic acid or salt thereof; and a cation
source present in an amount sufficient to neutralize greater than
80% of all acid groups present in the composition; and wherein the
specific gravity of the inner core is greater than the specific
gravity of the outer core layer.
14. The golf ball of claim 13, wherein the acid copolymer of
ethylene and an .alpha.,.beta.-unsaturated carboxylic acid does not
include a softening monomer, and wherein the acid is selected from
acrylic acid and methacrylic acid and is present in the acid
copolymer in an amount of from 15 mol % to 30 mol %.
15. The golf ball of claim 14, wherein the non-acid polymer is an
alkyl acrylate rubber selected from ethylene-alkyl acrylates and
ethylene-alkyl methacrylates and is present in an amount of greater
than 50 wt %, based on the combined weight of the acid copolymer
and the non-acid polymer.
16. The golf ball of claim 15, wherein the non-acid polymer is
ethylene-n-butyl acrylate, wherein the n-butyl-acrylate is present
in an amount of 20 wt % or greater, based on the total weight of
the non-acid polymer.
17. The golf ball of claim 16, wherein the highly neutralized
polymer composition has a solid sphere compression of 40 or less
and a coefficient of restitution of 0.820 or greater.
18. The golf ball of claim 14, wherein the non-acid polymer is an
alkyl acrylate rubber selected from ethylene-alkyl acrylates and
ethylene-alkyl methacrylates and is present in an amount of less
than 50 wt %, based on the combined weight of the acid copolymer
and the non-acid polymer.
19. The golf ball of claim 18, wherein the non-acid polymer is
ethylene-n-butyl acrylate, wherein the n-butyl-acrylate is present
in an amount of 20 wt % or greater, based on the total weight of
the non-acid polymer.
20. The golf ball of claim 19, wherein the highly neutralized
polymer composition has a solid sphere compression of 100 or
greater and a coefficient of restitution of 0.860 or greater.
21. The golf ball of claim 13, wherein the organic acid salt is
magnesium oleate, and wherein the magnesium oleate is present in an
amount of 30 parts or greater, per 100 parts of acid copolymer and
non-acid copolymer combined.
22. The golf ball of claim 21, wherein the cation source is present
in an amount sufficient to neutralize 110% or greater of all acid
groups present in the composition.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation-in-part of U.S. patent
application Ser. No. 13/606,099, filed Sep. 7, 2012, and U.S.
patent application Ser. No. 13/611,376, filed Sep. 12, 2012, the
entire disclosures of which are hereby incorporated herein by
reference.
FIELD OF THE INVENTION
[0002] The present invention generally relates to multi-piece golf
balls having a solid core of at least two layers and cover of at
least one layer. Preferably, the ball contains a dual-layered core
having a small, heavy inner core (center) containing a metal
material. At least one outer core layer is disposed about the inner
core. The outer core layer(s) are each formed from a thermoset
material such as rubber or a thermoplastic material such as a
highly neutralized ethylene acid copolymer. The core layers have
different hardness gradients and specific gravity values to provide
finished balls having high resiliency and spin-control
properties.
BACKGROUND OF THE INVENTION
[0003] Multi-piece, solid golf balls having a solid inner core
protected by a cover are used today by recreational and
professional golfers. The golf balls may have single-layered or
multi-layered cores. Normally, the core layers are made of a highly
resilient natural or synthetic rubber material such as styrene
butadiene, polybutadiene, poly(cis-isoprene), or
poly(trans-isoprene); or highly neutralized ethylene acid
copolymers (HNPs). The covers may be single or multi-layered and
made of a durable material such as HNPs, polyamides, polyesters,
polyurethanes, or polyureas. Manufacturers of golf balls use
different constructions (for example, three-piece, four-piece, and
five-piece balls) to impart specific properties and features to the
balls.
[0004] The core is the primary source of resiliency for the golf
ball and is often referred to as the "engine" of the ball. The
resiliency or coefficient of restitution ("COR") of a golf ball (or
golf ball component, such as a core) means the ratio of a ball's
rebound velocity to its initial incoming velocity when the ball is
fired out of an air cannon into a rigid plate. The COR for a golf
ball is written as a decimal value between zero and one. A golf
ball may have different COR values at different initial velocities.
The United States Golf Association (USGA) sets limits on the
initial velocity of the ball so one objective of golf ball
manufacturers is to maximize the COR under these conditions. Balls
(or cores) with a high rebound velocity have a relatively high COR
value. Such golf balls rebound faster, retain more total energy
when struck with a club, and have longer flight distances as
opposed to balls with low COR values. These properties are
particularly important for long distance shots. For example, balls
having high resiliency and COR values tend to travel a far distance
when struck by a driver club from a tee. The spin rate of the ball
also is an important property. Balls having a relatively high spin
rate are particularly desirable for relatively short distance shots
made with irons and wedge clubs. Professional and highly skilled
recreational golfers can place a back-spin on such balls more
easily. By placing the right amount of spin and touch on the ball,
the golfer has better control over shot accuracy and placement.
This is particularly important for approach shots near the green
and helps improve scoring performance.
[0005] Over the years, golf ball manufacturers have looked at
adjusting the density or specific gravity among the multiple layers
of the golf ball to control its spin rate. In general, the total
weight of a golf ball has to conform to weight limits set by the
United States Golf Association ("USGA"). Although the total weight
of the golf ball is mandated, the distribution of weight within the
ball can vary. Redistributing the weight or mass of the golf ball
either towards the center of the ball or towards the outer surface
of the ball changes its flight and spin properties.
[0006] For example, the weight can be shifted towards the center of
the ball to increase the spin rate as described in Yamada, U.S.
Pat. No. 4,625,964. In the '964 patent, the core composition
preferably contains 100 parts by weight of polybutadiene rubber; 10
to 50 parts by weight of zinc acrylate or zinc methacrylate; 10 to
150 parts by weight of zinc oxide; and 1 to 5 parts by weight of
peroxide as a cross-linking or curing agent. The inner core has a
specific gravity of at least 1.50 in order to make the spin rate of
the ball comparable to wound balls. The ball further includes a
cover an intermediate layer disposed between the core and cover,
wherein the intermediate layer has a lower specific gravity than
the core.
[0007] Chikaraishi et al., U.S. Pat. No. 5,048,838 discloses a
three-piece golf ball containing a two-piece solid core and a
cover. The inner core has a diameter in the range of 15-25 mm, a
weight of 2-14 grams, a specific gravity of 1.2 to 4.0, and a
hardness of 55-80 JISC. The specific gravity of the outer core
layer is less than the specific gravity of the inner core by 0.1 to
3.0. less than the specific gravity of the inner core. The inner
and outer core layers are formed from rubber compositions.
[0008] Gentiluomo, U.S. Pat. No. 5,104,126 discloses a three-piece
ball with a dense inner core made of steel, lead, brass, zinc,
copper, and a filled elastomer, wherein the core has a specific
gravity of at least 1.25. The inner core is encapsulated by a lower
density syntactic foam composition, and the core construction is
encapsulated by an ionomer cover.
[0009] Yabuki et al., U.S. Pat. No. 5,482,285 discloses a
three-piece golf ball having an inner core and outer core
encapsulated by an ionomer cover. The specific gravity of the outer
core is reduced so that it falls within the range of 0.2 to 1.0.
The specific gravity of the inner core is adjusted so that the
total weight of the inner/outer core falls within a range of 32.0
to 39.0 g.
[0010] Nesbitt and Binette, U.S. Pat. No. 6,277,934 disclose a
non-wound, multi-piece golf ball containing a spherical metal core
component having a specific gravity of about 1.5 to about 19.4; and
an outer core layer disposed about said spherical metal core
component, wherein the core layer has a specific gravity of less
than 1.2. The metal core is preferably contains a metal selected
from steel, titanium, brass, lead, tungsten, molybdenum, copper,
nickel, iron, and combinations thereof. Polybutadiene rubber
compositions containing metallic powders can be used to form the
core. The core assembly preferably has a coefficient of restitution
of at least 0.730.
[0011] Sullivan, U.S. Pat. No. 6,494,795 discloses a golf ball
comprising an inner core having a specific gravity of greater than
1.8 encased within a first mantle surrounding the inner core. A
portion of the first mantle comprises a low specific gravity layer
having a specific gravity of less than 0.9. The core may be made
from a high density metal or from metal powder encased in a
polymeric binder. High density metals such as steel, tungsten,
lead, brass, bronze, copper, nickel, molybdenum, or alloys may be
used. The mantle layer surrounding the inner core may be made from
a thermoset or thermoplastic material such as epoxy, urethane,
polyester, polyurethane, or polyurea.
[0012] Sullivan, U.S. Pat. No. 6,692,380 discloses a golf ball
comprising an inner core having a specific gravity of at least 3, a
diameter of about 0.40 to about 0.60 inches and preferably
comprises a polymeric matrix of polyurethane, polyurea, or blends
thereof. The outer core may be made from a polybutadiene rubber.
The specific gravity of the compositions may be adjusted by adding
fillers such as metal powder, metal alloy powder, metal oxide,
metal stearates, particulates, and carbonaceous material.
[0013] Morgan and Jones, U.S. Pat. No. 6,986,717 discloses a golf
ball containing a high-specific gravity central sphere encapsulated
in a soft and resilient shell, preferably formed of a polybutadiene
rubber. This shell is subsequently wound with thread that is
preferably elastic to form a wound core. This wound core is then
covered with a cover material such as balata, gutta percha, an
ionomer or a blend of ionomers, polyurethane, polyurea-based
composition, and epoxy-urethane-based compositions. The sphere is
formed of metallic powder and a thermoset or thermoplastic binder
material. Metals such as tungsten, steel, brass, titanium, lead,
zinc, copper, bismuth, nickel, molybdenum, iron, bronze, cobalt,
silver, platinum, and gold can be used. Preferably, the metal
sphere has a specific gravity of at least 6.0 and a diameter of
less than 0.5 inches.
[0014] Although some conventional multi-layered core constructions
are generally effective in providing high resiliency golf balls,
there is a continuing need for improved core constructions in golf
balls. Particularly, it would be desirable to have multi-layered
core constructions with selective specific gravities and mass
densities to provide the ball with good flight distance along with
spin control. The present invention provides core constructions and
golf balls having such properties as well as other advantageous
features, and benefits.
SUMMARY OF THE INVENTION
[0015] In one embodiment, the present invention is directed to a
golf ball having a multi-layered core comprising a thermoplastic
inner core, a thermoset outer core layer disposed about the inner
core, and a cover. The inner core has a diameter of from 0.100
inches to 1.100 inches and the outer core layer has a thickness of
from 0.200 inches to 1.200 inches. The specific gravity of the
inner core is greater than the specific gravity of the outer core
layer. The inner core is formed from a metal material dispersed in
a polymer matrix. The polymer matrix is a highly neutralized
polymer composition comprising an acid copolymer of ethylene and an
.alpha.,.beta.-unsaturated carboxylic acid, optionally including a
softening monomer selected from the group consisting of alkyl
acrylates and methacrylates; a non-acid polymer selected from the
group consisting of polyolefins, polyamides, polyesters,
polyethers, polyurethanes, metallocene-catalyzed polymers,
single-site catalyst polymerized polymers, ethylene propylene
rubber, ethylene propylene diene rubber, styrenic block copolymer
rubbers, alkyl acrylate rubbers, and functionalized derivatives
thereof; an organic acid or salt thereof; and a cation source
present in an amount sufficient to neutralize greater than 80% of
all acid groups present in the composition. In a particular aspect
of this embodiment, the outer core layer has an outer surface of
from 40 Shore D to 85 Shore D, an inner surface hardness of from 42
Shore D to 87 Shore D, and a zero or negative hardness gradient. In
another particular aspect of this embodiment, the outer core layer
has an outer surface of from 43 Shore D to 88 Shore D, an inner
surface hardness of from 40 Shore D to 85 Shore D, and a positive
hardness gradient.
[0016] In another embodiment, the present invention is directed to
a golf ball having a multi-layered core comprising a thermoset
inner core, a thermoplastic outer core layer disposed about the
inner core, and a cover. The inner core has a diameter of from
0.100 inches to 1.100 inches and the outer core layer has a
thickness of from 0.200 inches to 1.200 inches. The specific
gravity of the inner core is greater than the specific gravity of
the outer core layer. The outer core layer is formed from a highly
neutralized polymer composition comprising an acid copolymer of
ethylene and an .alpha.,.beta.-unsaturated carboxylic acid,
optionally including a softening monomer selected from the group
consisting of alkyl acrylates and methacrylates; a non-acid polymer
selected from the group consisting of polyolefins, polyamides,
polyesters, polyethers, polyurethanes, metallocene-catalyzed
polymers, single-site catalyst polymerized polymers, ethylene
propylene rubber, ethylene propylene diene rubber, styrenic block
copolymer rubbers, alkyl acrylate rubbers, and functionalized
derivatives thereof; an organic acid or salt thereof; and a cation
source present in an amount sufficient to neutralize greater than
80% of all acid groups present in the composition. In a particular
aspect of this embodiment, the inner core has a positive hardness
gradient. In another particular aspect of this embodiment, the
inner core has a zero or negative hardness gradient.
[0017] In another embodiment, the present invention is directed to
a golf ball having a multi-layered core comprising a thermoplastic
inner core, a thermoplastic outer core layer disposed about the
inner core, and a cover. The inner core has a diameter of from
0.100 inches to 1.100 inches and the outer core layer has a
thickness of from 0.200 inches to 1.200 inches. The specific
gravity of the inner core is greater than the specific gravity of
the outer core layer. The inner core is formed from a metal
material dispersed in a polymer matrix. The polymer matrix is a
first highly neutralized polymer composition. The outer core layer
is formed from a second highly neutralized polymer composition. At
least one or the first highly neutralized polymer composition and
the second highly neutralized polymer composition comprises an acid
copolymer of ethylene and an .alpha.,.beta.-unsaturated carboxylic
acid, optionally including a softening monomer selected from the
group consisting of alkyl acrylates and methacrylates; a non-acid
polymer selected from the group consisting of polyolefins,
polyamides, polyesters, polyethers, polyurethanes,
metallocene-catalyzed polymers, single-site catalyst polymerized
polymers, ethylene propylene rubber, ethylene propylene diene
rubber, styrenic block copolymer rubbers, alkyl acrylate rubbers,
and functionalized derivatives thereof; an organic acid or salt
thereof; and a cation source present in an amount sufficient to
neutralize greater than 80% of all acid groups present in the
composition.
[0018] In the above embodiments, the highly neutralized composition
comprising an acid copolymer, a non-acid polymer, an organic acid
or salt thereof, and a cation source optionally has one or more of
the following properties: [0019] (a) the acid copolymer does not
include a softening monomer; [0020] (b) the acid of the acid
copolymer is selected from acrylic acid and methacrylic acid;
[0021] (c) the acid of the acid copolymer is present in the acid
copolymer in an amount of from 15 mol % to 30 mol %, based on the
total weight of the acid copolymer; [0022] (d) the non-acid polymer
is an alkyl acrylate rubber selected from ethylene-alkyl acrylates
and ethylene-alkyl methacrylates; [0023] (e) the non-acid polymer
is present in an amount of greater than 50 wt %, based on the
combined weight of the acid copolymer and the non-acid polymer;
[0024] (f) the non-acid polymer is present in an amount of 20 wt %
or greater, based on the total weight of the highly neutralized
composition; [0025] (g) the non-acid polymer is present in an
amount of less than 50 wt %, based on the combined weight of the
acid copolymer and the non-acid polymer; [0026] (h) the highly
neutralized polymer composition has a solid sphere compression of
40 or less and a coefficient of restitution of 0.820 or greater;
[0027] (i) the highly neutralized polymer composition has a solid
sphere compression of 100 or greater and a coefficient of
restitution of 0.860 or greater; [0028] (j) the organic acid salt
is a metal salt of oleic acid; [0029] (k) the organic salt is
magnesium oleate; [0030] (l) the organic salt is present in an
amount of 30 parts or greater, per 100 parts of acid copolymer and
non-acid copolymer combined; and [0031] (m) the cation source is
present in an amount sufficient to neutralize 110% or greater of
all acid groups present in the composition.
BRIEF DESCRIPTION OF THE DRAWINGS
[0032] The novel features that are characteristic of the present
invention are set forth in the appended claims. However, the
preferred embodiments of the invention, together with further
objects and attendant advantages, are best understood by reference
to the following detailed description in connection with the
accompanying drawings in which:
[0033] FIG. 1 is a cross-sectional view of a three-piece golf ball
having a dual-layered core made in accordance with the present
invention; and
[0034] FIG. 2 is a cross-sectional view of a four-piece golf ball
having a dual-layered core made in accordance with the present
invention.
DETAILED DESCRIPTION OF THE INVENTION
Golf Ball Constructions
[0035] Golf balls having various constructions may be made in
accordance with this invention. For example, golf balls having
three-piece, four-piece, and five-piece constructions with single
or multi-layered cover materials may be made. The term, "layer" as
used herein means generally any spherical portion of the golf ball.
More particularly, in one version, a three-piece golf ball having a
dual-core and cover is made. The dual-core includes an inner core
(center) and surrounding outer core layer. In another version, a
four-piece golf ball comprising a dual-core and dual-cover (inner
cover and outer cover layers) is made. In yet another construction,
a four-piece or five-piece golf ball having a multi-layered core;
an intermediate (casing) layer, and cover layer(s) may be made. As
used herein, the term, "intermediate layer" means a layer of the
ball disposed between the core and cover. The intermediate layer
also may be referred to as a casing or mantle layer. The diameter
and thickness of the different layers along with properties such as
hardness and compression may vary depending upon the construction
and desired playing performance properties of the golf ball.
[0036] Referring to FIG. 1, one version of a golf ball that can be
made in accordance with this invention is generally indicated at
(12). The ball (12) contains a multi-layered core (14) having an
inner core (center) (14a) and outer core layer (14b) surrounded by
a single-layered cover (16). The inner core (14a) is relatively
small in volume and generally has a diameter within a range of
about 0.10 to about 1.10 inches. More particularly, the inner core
(14a) preferably has a diameter size with a lower limit of about
0.15 or 0.25 or 0.35 or 0.45 or 0.55 inches and an upper limit of
about 0.60 or 0.70 or 0.80 or 0.90 inches. In one preferred
version, the diameter of the inner core (14a) is in the range of
about 0.025 to about 0.080 inches, more preferably about 0.030 to
about 0.075 inches. Meanwhile, the outer core layer (14b) generally
has a thickness within a range of about 0.010 to about 0.250 inches
and preferably has a lower limit of 0.010 or 0.020 or 0.025 or
0.030 inches and an upper limit of 0.070 or 0.080 or 0.100 or 0.200
inches. In one preferred version, the outer core layer has a
thickness in the range of about 0.040 to about 0.170 inches, more
preferably about 0.060 to about 0.150 inches. Referring to FIG. 2,
in another version, the golf ball (18) contains a dual-core (20)
having an inner core (center) (20a) and outer core layer (20b). The
dual-core (20) is surrounded by a multi-layered cover (22) having
an inner cover layer (22a) and outer cover layer (22b).
[0037] Golf balls made in accordance with this invention can be of
any size, although the USGA requires that golf balls used in
competition have a diameter of at least 1.68 inches. For play
outside of United States Golf Association (USGA) rules, the golf
balls can be of a smaller size. Normally, golf balls are
manufactured in accordance with USGA requirements and have a
diameter in the range of about 1.68 to about 1.80 inches. In
general, the multi-layer core structure (14) has an overall
diameter within a range having a lower limit of about 1.00 or 1.20
or 1.30 or 1.40 inches and an upper limit of about 1.58 or 1.60 or
1.62 or 1.66 inches, and more preferably in the range of about 1.3
to 1.65 inches. In one embodiment, the diameter of the core
subassembly (14) is in the range of about 1.45 to about 1.62
inches.
[0038] As discussed further below, various compositions may be used
to make the dual-core structures of the golf balls of this
invention. The golf balls may contain certain fillers to adjust the
specific gravity and weight of the core layers as needed. In
general, the inner core (center) has a specific gravity within a
range having a lower limit of about 1.18 or 1.50 or 2.00 or 2.50
g/cc and an upper limit of about 3.00 or 3.50 or 4.00 or 4.50 or
5.00 g/cc. In a preferred embodiment, the inner core has a specific
gravity of about 1.20 to about 3.50 g/cc, more preferably about
1.25 to about 3.00 g/cc. Meanwhile, the outer core layer (14b)
preferably has a relatively low specific gravity. The outer core
layer (14b) generally has a specific gravity within a range having
a lower limit of about 0.080 or 0.100 or 0.400 or 0.600 or 0.800
g/cc and an upper limit of about 1.00 or 1.10 or 1.20 g/cc. The
amount of fillers used in the compositions is adjusted so the
weight of the golf ball does not exceed limits set by USGA rules.
The USGA has established a maximum weight of 45.93 g (1.62 ounces).
For play outside of USGA rules, the golf balls can be heavier. In
one preferred embodiment, the weight of the multi-layered core is
in the range of about 28 to about 38 grams.
Core Structure
[0039] As discussed above, the core preferably has a dual-layered
structure comprising an inner core and surrounding outer core
layer. The hardness of the core subassembly is an important
property. In general, cores with relatively high hardness values
have higher compression and tend to have good durability and
resiliency. However, some high compression balls are stiff and this
may have a detrimental effect on shot control. For example, some of
these harder balls tend to have a low spin rate and this makes the
ball more difficult to control. This can be particularly troubling
when making approach shots near the green. Thus, the optimum
balance of hardness in the core subassembly needs to be
attained.
[0040] In one preferred golf ball, the inner core (center) has a
"positive" hardness gradient (that is, the outer surface of the
inner core is harder than its geometric center) and the outer core
layer has a "positive" hardness gradient (that is, the outer
surface of the outer core layer is harder than the inner surface of
the outer core layer.) In such cases where both the inner core and
outer core layer have "positive" hardness gradients, the outer
surface hardness of the outer core layer is preferably greater than
the material hardness of the inner core (center). In an alternative
version, the inner core may have a positive hardness gradient and
the outer core layer may have a "zero" hardness gradient (that is,
the hardness values of the outer surface of the outer core layer
and the inner surface of the outer core layer are substantially the
same) or a "negative" hardness gradient (that is, the outer surface
of the outer core layer is softer than the inner surface of the
outer core layer.)
[0041] In another version, the inner core (center) has a zero or
negative hardness gradient, while the outer core layer has a
positive hardness gradient. In yet another version, both the inner
core and outer core layer have a zero or negative hardness
gradient. Such hardness gradients are further described in Bulpett
et al., U.S. Pat. Nos. 7,537,529 and 7,410,429, the disclosures of
which are hereby incorporated by reference. Methods for measuring
the hardness of the inner core and outer core layers along with
other layers in the golf ball and determining the hardness
gradients of the layers are described in further detail below.
[0042] The core layers have positive, negative, or zero hardness
gradients defined by hardness measurements made at the outer
surface of the inner core (or outer surface of the outer core
layer) and radially inward towards the center of the inner core (or
inner surface of the inner core layer). These measurements are made
typically at 2-mm increments as described in the test methods
below. In general, the hardness gradient is determined by
subtracting the hardness value at the innermost portion of the
component being measured (for example, the center of the inner core
or inner surface of the outer core layer) from the hardness value
at the outer surface of the component being measured (for example,
the outer surface of the inner core or outer surface of the outer
core layer).
[0043] Positive Hardness Gradient.
[0044] For example, if the hardness value of the outer surface of
the inner core is greater than the hardness value of the inner
core's geometric center (that is, the inner core has a surface
harder than its center), the hardness gradient will be deemed
"positive" (a larger number minus a smaller number equals a
positive number.) For example, if the outer surface of the inner
core has a hardness of 58 Shore D and the center of the inner core
has a hardness of 50 Shore D, then the inner core has a positive
hardness gradient of 8 Likewise, if the outer surface of the outer
core layer has a greater hardness value than the inner surface of
the outer core layer, the outer core layer will be considered to
have a positive hardness gradient.
[0045] Negative Hardness Gradient.
[0046] On the other hand, if the hardness value of the outer
surface of the inner core is less than the hardness value of the
inner core's geometric center (that is, the inner core has a
surface softer than its center), the hardness gradient will be
deemed "negative." For example, if the outer surface of the inner
core has a hardness of 68 Shore C and the center of the inner core
has a hardness of 70 Shore C, then the inner core has a negative
hardness gradient of 2. Likewise, if the outer surface of the outer
core layer has a lesser hardness value than the inner surface of
the outer core layer, the outer core layer will be considered to
have a negative hardness gradient.
[0047] Zero Hardness Gradient.
[0048] In another example, if the hardness value of the outer
surface of the inner core is substantially the same as the hardness
value of the inner core's geometric center (that is, the surface of
the inner core has about the same hardness as the center), the
hardness gradient will be deemed "zero." For example, if the outer
surface of the inner core and the center of the inner core has a
hardness of 65 Shore C, then the inner core has a zero hardness
gradient. Likewise, if the outer surface of the outer core layer
has a hardness value approximately the same as the inner surface of
the outer core layer, the outer core layer will be considered to
have a zero hardness gradient.
[0049] More particularly, the term, "positive hardness gradient" as
used herein means a hardness gradient of positive 3 Shore D or
greater, preferably 7 Shore D or greater, more preferably 10 Shore
D, and even more preferably 20 Shore D or greater. The term, "zero
hardness gradient" as used herein means a hardness gradient of less
than 3 Shore D, preferably less than 1 Shore D and may have a value
of zero or negative 1 to negative 10 Shore D. The term, "negative
hardness gradient" as used herein means a hardness value of less
than zero, for example, negative 3, negative 5, negative 7,
negative 10, negative 15, or negative 20 or negative 25. The terms,
"zero hardness gradient" and "negative hardness gradient" may be
used herein interchangeably to refer to hardness gradients of
negative 1 to negative 10.
[0050] The inner core (center) preferably has a geometric center
hardness (H.sub.center material) of about 25 Shore D or greater and
more preferably within a range having a lower limit of about 26 or
30 or 34 or 36 or 38 or 42 or 48 of 50 or 52 Shore D and an upper
limit of about 54 or 56 or 58 or 60 or 62 Shore D. The center
hardness (H.sub.center material) of the inner core, as measured in
Shore C units, preferably has a lower limit of about 38 or 44 or 52
or 58 or 60 or 70 or 74 Shore C and an upper limit of about 76 or
78 or 80 or 84 or 86 or 88 or 90 or 92 Shore C. Concerning the
outer surface hardness (H.sub.center surface) of the inner core,
this hardness is preferably about 25 Shore D or greater. and more
preferably within a range having a lower limit of about 26 or 30 or
34 or 36 or 38 or 42 or 48 of 50 or 52 Shore D and an upper limit
of about 54 or 56 or 58 or 60 or 62 Shore D.
[0051] Meanwhile, the outer core layer preferably has an outer
surface hardness (H.sub.outer surface of OC) of about 40 Shore D or
greater, and more preferably within a range having a lower limit of
about 40 or 42 or 44 or 46 or 48 or 50 or 52 and an upper limit of
about 54 or 56 or 58 or 60 or 62 or 64 or 70 or 74 or 78 or 80 or
82 or 85 or 87 or 88 or 90 Shore D. The outer surface hardness of
the outer core layer (H.sub.outer surface of OC), as measured in
Shore C units, preferably has a lower limit of about 63 or 65 or 67
or 70 or 73 or 76 Shore C, and an upper limit of about 78 or 80 or
85 or 87 or 89 or 90 or 92 or 95 Shore C, And, the inner surface of
the outer core (H.sub.inner surface of the OC) preferably has a
hardness of about 40 Shore D or greater, and more preferably within
a range having a lower limit of about 40 or 42 or 44 or 46 or 48 or
50 or 52 and an upper limit of about 54 or 56 or 58 or 60 or 62 or
64 or 70 or 74 or 78 or 80 or 82 or 85 or 87 or 88 or 90 Shore
D.
Inner Core Composition
[0052] Preferably, the inner core composition comprises a metal
material such as, for example, copper, steel, brass, tungsten,
titanium, aluminum, magnesium, molybdenum, cobalt, nickel, iron,
lead, tin, bronze, silver, gold, and platinum, and alloys and
combinations thereof. The metal material may be dispersed in a
polymeric matrix, preferably a thermoset rubber material. The metal
material is dispersed uniformly in the polymeric matrix to provide
a substantially homogenous composition. The metal material is
blended fully into the polymeric matrix to prevent agglomerates and
aggregates from being formed. The resulting metal-containing
composition is used to form an inner core structure having a
relatively high specific gravity, thereby providing a ball having a
lower moment of inertia as discussed further below.
[0053] Suitable thermoset rubber materials that may be used as the
polymeric binder material are natural and synthetic rubbers
including, but not limited to, polybutadiene, polyisoprene,
ethylene propylene rubber ("EPR"), ethylene-propylene-diene
("EPDM") rubber, styrene-butadiene rubber, styrenic block copolymer
rubbers (such as "SI", "SIS", "SB", "SBS", "SIBS", and the like,
where "S" is styrene, "I" is isobutylene, and "B" is butadiene),
polyalkenamers such as, for example, polyoctenamer, butyl rubber,
halobutyl rubber, polystyrene elastomers, polyethylene elastomers,
polyurethane elastomers, polyurea elastomers, metallocene-catalyzed
elastomers and plastomers, copolymers of isobutylene and
p-alkylstyrene, halogenated copolymers of isobutylene and
p-alkylstyrene, copolymers of butadiene with acrylonitrile,
polychloroprene, alkyl acrylate rubber, chlorinated isoprene
rubber, acrylonitrile chlorinated isoprene rubber, and blends of
two or more thereof.
[0054] Preferably, the rubber composition comprises polybutadiene.
In general, polybutadiene is a homopolymer of 1,3-butadiene. The
double bonds in the 1,3-butadiene monomer are attacked by catalysts
to grow the polymer chain and form a polybutadiene polymer having a
desired molecular weight. Any suitable catalyst may be used to
synthesize the polybutadiene rubber depending upon the desired
properties. Normally, a transition metal complex (for example,
neodymium, nickel, or cobalt) or an alkyl metal such as
alkyllithium is used as a catalyst. Other catalysts include, but
are not limited to, aluminum, boron, lithium, titanium, and
combinations thereof. The catalysts produce polybutadiene rubbers
having different chemical structures. In a cis-bond configuration,
the main internal polymer chain of the polybutadiene appears on the
same side of the carbon-carbon double bond contained in the
polybutadiene. In a trans-bond configuration, the main internal
polymer chain is on opposite sides of the internal carbon-carbon
double bond in the polybutadiene. The polybutadiene rubber can have
various combinations of cis- and trans-bond structures. A preferred
polybutadiene rubber has a 1,4 cis-bond content of at least 40%,
preferably greater than 80%, and more preferably greater than 90%.
In general, polybutadiene rubbers having a high 1,4 cis-bond
content have high tensile strength. The polybutadiene rubber may
have a relatively high or low Mooney viscosity.
[0055] Examples of commercially available polybutadiene rubbers
that can be used in accordance with this invention, include, but
are not limited to, BR 01 and BR 1220, available from BST
Elastomers of Bangkok, Thailand; SE BR 1220LA and SE BR1203,
available from DOW Chemical Co of Midland, Mich.; BUDENE 1207,
1207s, 1208, and 1280 available from Goodyear, Inc of Akron, Ohio;
BR 01, 51 and 730, available from Japan Synthetic Rubber (JSR) of
Tokyo, Japan; BUNA CB 21, CB 22, CB 23, CB 24, CB 25, CB 29 MES, CB
60, CB Nd 60, CB 55 NF, CB 70 B, CB KA 8967, and CB 1221, available
from Lanxess Corp. of Pittsburgh, Pa.; BR1208, available from LG
Chemical of Seoul, South Korea; UBEPOL BR130B, BR150, BR150B,
BR150L, BR230, BR360L, BR710, and VCR617, available from UBE
Industries, Ltd. of Tokyo, Japan; EUROPRENE NEOCIS BR 60, INTENE 60
AF and P30AF, and EUROPRENE BR HV80, available from Polimeri Europa
of Rome, Italy; AFDENE 50 and NEODENE BR40, BR45, BR50 and BR60,
available from Karbochem (PTY) Ltd. of Bruma, South Africa; KBR 01,
NdBr 40, NdBR-45, NdBr 60, KBR 710S, KBR 710H, and KBR 750,
available from Kumho Petrochemical Co., Ltd. Of Seoul, South Korea;
DIENE 55NF, 70AC, and 320 AC, available from Firestone Polymers of
Akron, Ohio; and PBR-Nd Group II and Group III, available from
Nizhnekamskneftekhim, Inc. of Nizhnekamsk, Tartarstan Republic.
[0056] The polybutadiene rubber is used in an amount of at least
about 5% by weight based on total weight of composition and is
generally present in an amount of about 5% to about 100%, or an
amount within a range having a lower limit of 5% or 10% or 20% or
30% or 40% or 50% and an upper limit of 55% or 60% or 70% or 80% or
90% or 95% or 100%. Preferably, the concentration of polybutadiene
rubber is about 40 to about 95 weight percent. If desirable, lesser
amounts of other thermoset materials may be incorporated into the
base rubber. Such materials include the rubbers discussed above,
for example, cis-polyisoprene, trans-polyisoprene, balata,
polychloroprene, polynorbornene, polyoctenamer, polypentenamer,
butyl rubber, EPR, EPDM, styrene-butadiene, and the like.
[0057] In another version, a thermoplastic material may be used as
the polymeric binder in the composition used to make the inner
core. These thermoplastic polymers include, for example, ethylene
acid copolymers containing acid groups that are at least partially
neutralized. Preferably, the neutralization level is greater than
70%, more preferably at least 90%, and even more preferably at
least 100%. Such ethylene acid copolymers having a neutralization
level of 70% or greater are commonly referred to as highly
neutralized polymers (HNPs). Suitable ethylene acid copolymers that
may be used to form the compositions of this invention are
generally referred to as copolymers of ethylene; C.sub.3 to C.sub.8
.alpha.,.beta.-ethylenically unsaturated mono- or dicarboxylic
acid; and optional softening monomer. Copolymers may include,
without limitation, ethylene acid copolymers, such as
ethylene/(meth)acrylic acid, ethylene/(meth)acrylic acid/maleic
anhydride, ethylene/(meth)acrylic acid/maleic acid mono-ester,
ethylene/maleic acid, ethylene/maleic acid mono-ester,
ethylene/(meth)acrylic acid/n-butyl (meth)acrylate,
ethylene/(meth)acrylic acid/iso-butyl (meth)acrylate,
ethylene/(meth)acrylic acid/methyl (meth)acrylate,
ethylene/(meth)acrylic acid/ethyl (meth)acrylate terpolymers, and
the like. Other thermoplastics such as polyamides,
polyamide-ethers, and polyamide-esters, polyurethanes, polyureas,
polyurethane-polyurea hybrids, polyesters, polyolefins,
polystyrenes, and blends thereof may be used.
[0058] In a particular embodiment, the thermoplastic material used
as the polymeric binder in the composition used to make the inner
core is an HNP composition comprising an HNP and optionally melt
flow modifier(s), additive(s), and/or filler(s). It is understood
that the HNP may be a blend of two or more HNPs. Preferred acid
polymers are copolymers of an .alpha.-olefin and a C.sub.3-C.sub.8
.alpha.,.beta.-ethylenically unsaturated carboxylic acid,
optionally including a softening monomer. The .alpha.-olefin is
preferably selected from ethylene and propylene. The acid is
preferably selected from (meth) acrylic acid, ethacrylic acid,
maleic acid, crotonic acid, fumaric acid, and itaconic acid. (Meth)
acrylic acid is particularly preferred. The optional softening
monomer is preferably selected from alkyl (meth)acrylate, wherein
the alkyl groups have from 1 to 8 carbon atoms. Preferred acid
polymers include, but are not limited to, those wherein the
.alpha.-olefin is ethylene, the acid is (meth) acrylic acid, and
the optional softening monomer is selected from (meth)acrylate,
n-butyl (meth)acrylate, isobutyl (meth)acrylate, methyl
(meth)acrylate, and ethyl (meth) acrylate. Particularly preferred
acid polymers include, but are not limited to, ethylene/(meth)
acrylic acid/n-butyl acrylate, ethylene/(meth) acrylic acid/methyl
acrylate, and ethylene/(meth) acrylic acid/ethyl acrylate.
[0059] Suitable acid polymers for forming the HNP also include acid
polymers that are already partially neutralized. Examples of
suitable partially neutralized acid polymers include, but are not
limited to, Surlyn.RTM. ionomers, commercially available from E. I.
du Pont de Nemours and Company; AClyn.RTM. ionomers, commercially
available from Honeywell International Inc.; and Iotek.RTM.
ionomers, commercially available from ExxonMobil Chemical Company.
Also suitable are DuPont.RTM. HPF 1000 and DuPont.RTM. HPF 2000,
ionomeric materials commercially available from E. I. du Pont de
Nemours and Company. In some embodiments, very low modulus ionomer-
("VLMI-") type ethylene-acid polymers are particularly suitable for
forming the HNP, such as Surlyn.RTM. 6320, Surlyn.RTM. 8120,
Surlyn.RTM. 8320, and Surlyn.RTM. 9320, commercially available from
E. I. du Pont de Nemours and Company.
[0060] The .alpha.-olefin is typically present in the acid polymer
in an amount of 15 wt % or greater, or 25 wt % or greater, or 40 wt
% or greater, or 60 wt % or greater, based on the total weight of
the acid polymer. The acid is typically present in the acid polymer
in an amount within a range having a lower limit of 1 or 2 or 4 or
6 or 8 or 10 or 12 or 15 or 16 or 20 wt % and an upper limit of 20
or 25 or 26 or 30 or 35 or 40 wt %, based on the total weight of
the acid polymer. The optional softening monomer is typically
present in the acid polymer in an amount within a range having a
lower limit of 0 or 1 or 3 or 5 or 11 or 15 or 20 wt % and an upper
limit of 23 or 25 or 30 or 35 or 50 wt %, based on the total weight
of the acid polymer. Additional suitable acid polymers are more
fully described, for example, in U.S. Pat. Nos. 5,691,418,
6,562,906, 6,653,382, 6,777,472, 6,762,246, 6,815,480, and
6,953,820 and U.S. Patent Application Publication Nos.
2005/0148725, 2005/0049367, 2005/0020741, 2004/0220343, and
2003/0130434, the entire disclosures of which are hereby
incorporated herein by reference.
[0061] The HNP is formed by reacting the acid polymer with a
sufficient amount of cation source, optionally in the presence of a
high molecular weight organic acid or salt thereof, such that at
least 70%, preferably at least 80%, more preferably at least 90%,
more preferably at least 95%, and even more preferably 100%, of all
acid groups present are neutralized. In a particular embodiment,
the cation source is present in an amount sufficient to neutralize,
theoretically, greater than 100%, or 105% or greater, or 110% or
greater, or 115% or greater, or 120% or greater, or 125% or
greater, or 200% or greater, or 250% or greater of all acid groups
present in the composition. The acid polymer can be reacted with
the optional high molecular weight organic acid or salt thereof and
the cation source simultaneously, or the acid polymer can be
reacted with the optional high molecular weight organic acid or
salt thereof prior to the addition of the cation source.
[0062] Suitable cation sources include metal ions and compounds of
alkali metals, alkaline earth metals, and transition metals; metal
ions and compounds of rare earth elements; silicone, silane, and
silicate derivatives and complex ligands; and combinations thereof.
Preferred cation sources are metal ions and compounds of magnesium,
sodium, potassium, cesium, calcium, barium, manganese, copper,
zinc, tin, lithium, and rare earth metals. The acid polymer may be
at least partially neutralized prior to contacting the acid polymer
with the cation source to form the HNP. Methods of preparing
ionomers, and the acid polymers on which ionomers are based, are
disclosed, for example, in U.S. Pat. Nos. 3,264,272, and 4,351,931,
and U.S. Patent Application Publication No. 2002/0013413.
[0063] Suitable high molecular weight organic acids are aliphatic
organic acids, aromatic organic acids, saturated monofunctional
organic acids, unsaturated monofunctional organic acids,
multi-unsaturated monofunctional organic acids, and dimerized
derivatives thereof. Particular examples of suitable organic acids
include, but are not limited to, caproic acid, caprylic acid,
capric acid, lauric acid, stearic acid, behenic acid, erucic acid,
oleic acid, linoleic acid, myristic acid, benzoic acid, palmitic
acid, phenylacetic acid, naphthalenoic acid, dimerized derivatives
thereof, and combinations thereof. Salts of high molecular weight
organic acids comprise the salts, particularly the barium, lithium,
sodium, zinc, bismuth, chromium, cobalt, copper, potassium,
stontium, titanium, tungsten, magnesium, and calcium salts, of
aliphatic organic acids, aromatic organic acids, saturated
monofunctional organic acids, unsaturated monofunctional organic
acids, multi-unsaturated monofunctional organic acids, dimerized
derivatives thereof, and combinations thereof. Suitable organic
acids and salts thereof are more fully described, for example, in
U.S. Pat. No. 6,756,436, the entire disclosure of which is hereby
incorporated herein by reference. In a particular embodiment, the
HNP composition comprises an organic acid salt in an amount of 20
phr or greater, or 25 phr or greater, or 30 phr or greater, or 35
phr or greater, or 40 phr or greater.
[0064] HNP compositions of the present invention optionally contain
one or more melt flow modifiers. The amount of melt flow modifier
in the composition is readily determined such that the melt flow
index of the composition is at least 0.1 g/10 min, preferably from
0.5 g/10 min to 10.0 g/10 min, and more preferably from 1.0 g/10
min to 6.0 g/10 min, as measured using ASTM D-1238, condition E, at
190.degree. C., using a 2160 gram weight.
[0065] Suitable melt flow modifiers include, but are not limited
to, the high molecular weight organic acids and salts thereof
disclosed above, polyamides, polyesters, polyacrylates,
polyurethanes, polyethers, polyureas, polyhydric alcohols, and
combinations thereof. Also suitable are the non-fatty acid melt
flow modifiers disclosed in U.S. Pat. Nos. 7,365,128 and 7,402,629,
the entire disclosures of which are hereby incorporated herein by
reference.
[0066] HNP compositions of the present invention optionally include
additive(s) and/or filler(s) in an amount within a range having a
lower limit of 0 or 5 or 10 wt %, and an upper limit of 15 or 20 or
25 or 30 or 50 wt %, based on the total weight of the composition.
Suitable additives and fillers include, but are not limited to,
chemical blowing and foaming agents, optical brighteners, coloring
agents, fluorescent agents, whitening agents, UV absorbers, light
stabilizers, defoaming agents, processing aids, mica, talc,
nano-fillers, antioxidants, stabilizers, softening agents,
fragrance components, plasticizers, impact modifiers, TiO.sub.2,
acid copolymer wax, surfactants, and fillers, such as zinc oxide,
tin oxide, barium sulfate, zinc sulfate, calcium oxide, calcium
carbonate, zinc carbonate, barium carbonate, clay, tungsten,
tungsten carbide, silica, lead silicate, regrind (recycled
material), and mixtures thereof. Suitable additives are more fully
disclosed, for example, in U.S. Patent Application Publication No.
2003/0225197, the entire disclosure of which is hereby incorporated
herein by reference.
[0067] In some embodiments, the HNP composition is a "moisture
resistant" HNP composition, i.e., having a moisture vapor
transmission rate ("MVTR") of 8 g-mil/100 in.sup.2/day or less
(i.e., 3.2 g-mm/m.sup.2day or less), or 5 g-mil/100 in.sup.2/day or
less (i.e., 2.0 g-mm/m.sup.2day or less), or 3 g-mil/100
in.sup.2/day or less (i.e., 1.2 g-mm/m.sup.2day or less), or 2
g-mil/100 in.sup.2/day or less (i.e., 0.8 g-mm/m.sup.2day or less),
or 1 g-mil/100 in.sup.2/day or less (i.e., 0.4 g-mm/m.sup.2day or
less), or less than 1 g-mil/100 in.sup.2/day (i.e., less than 0.4
g-mm/m.sup.2day). Suitable moisture resistant HNP compositions are
disclosed, for example, in U.S. Patent Application Publication Nos.
2005/0267240, 2006/0106175, and 2006/0293464, the entire
disclosures of which are hereby incorporated herein by
reference.
[0068] HNP compositions of the present invention are not limited by
any particular method or any particular equipment for making the
compositions. In a preferred embodiment, the composition is
prepared by the following process. The acid polymer(s), optional
melt flow modifier(s), and optional additive(s)/filler(s) are
simultaneously or individually fed into a melt extruder, such as a
single or twin screw extruder. A suitable amount of cation source
is then added such that at least 70%, or at least 80%, or at least
90%, or at least 95%, or at least 100%, of all acid groups present
are neutralized. Optionally, the cation source is added in an
amount sufficient to neutralize, theoretically, 105% or greater, or
110% or greater, or 115% or greater, or 120% or greater, or 125% or
greater, or 200% or greater, or 250% or greater of all acid groups
present in the composition. The acid polymer may be at least
partially neutralized prior to the above process. The components
are intensively mixed prior to being extruded as a strand from the
die-head.
[0069] The HNP composition optionally comprises at least one
additional polymer component selected from partially neutralized
ionomers as disclosed, for example, in U.S. Patent Application
Publication No. 2006/0128904, the entire disclosure of which is
hereby incorporated herein by reference; bimodal ionomers, such as
those disclosed in U.S. Patent Application Publication No.
2004/0220343 and U.S. Pat. Nos. 6,562,906, 6,762,246, 7,273,903,
8,193,283, 8,410,219, and 8,410,220, the entire disclosures of
which are hereby incorporated herein by reference, and particularly
Surlyn.RTM. AD 1043, 1092, and 1022 ionomer resins, commercially
available from E. I. du Pont de Nemours and Company; ionomers
modified with rosins, such as those disclosed in U.S. Patent
Application Publication No. 2005/0020741, the entire disclosure of
which is hereby incorporated by reference; soft and resilient
ethylene copolymers, such as those disclosed U.S. Patent
Application Publication No. 2003/0114565, the entire disclosure of
which is hereby incorporated herein by reference; polyolefins, such
as linear, branched, or cyclic, C.sub.2-C.sub.40 olefins,
particularly polymers comprising ethylene or propylene
copolymerized with one or more C.sub.2-C.sub.40 olefins,
C.sub.3-C.sub.20 .alpha.-olefins, or C.sub.3-C.sub.10
.alpha.-olefins; polyamides; polyesters; polyethers;
polycarbonates; polysulfones; polyacetals; polylactones;
acrylonitrile-butadiene-styrene resins; polyphenylene oxide;
polyphenylene sulfide; styrene-acrylonitrile resins; styrene maleic
anhydride; polyimides; aromatic polyketones; ionomers and ionomeric
precursors, acid copolymers, and conventional HNPs, such as those
disclosed in U.S. Pat. Nos. 6,756,436, 6,894,098, and 6,953,820,
the entire disclosures of which are hereby incorporated herein by
reference; polyurethanes; grafted and non-grafted
metallocene-catalyzed polymers, such as single-site catalyst
polymerized polymers, high crystalline acid polymers, cationic
ionomers, and combinations thereof; natural and synthetic rubbers,
including, but not limited to, ethylene propylene rubber ("EPR"),
ethylene propylene diene rubber ("EPDM"), styrenic block copolymer
rubbers (such as SI, SIS, SB, SBS, SIBS, and the like, where "S" is
styrene, "I" is isobutylene, and "B" is butadiene), butyl rubber,
halobutyl rubber, copolymers of isobutylene and para-alkylstyrene,
halogenated copolymers of isobutylene and para-alkylstyrene,
natural rubber, polyisoprene, copolymers of butadiene with
acrylonitrile, polychloroprene, alkyl acrylate rubber (such as
ethylene-alkyl acrylates and ethylene-alkyl methacrylates, and,
more specifically, ethylene-ethyl acrylate, ethylene-methyl
acrylate, and ethylene-butyl acrylate), chlorinated isoprene
rubber, acrylonitrile chlorinated isoprene rubber, and
polybutadiene rubber (cis and trans). Additional suitable blend
polymers include those described in U.S. Pat. No. 5,981,658, for
example at column 14, lines 30 to 56, the entire disclosure of
which is hereby incorporated herein by reference. The blend may be
produced by post-reactor blending, by connecting reactors in series
to make reactor blends, or by using more than one catalyst in the
same reactor to produce multiple species of polymer. The polymers
may be mixed prior to being put into an extruder, or they may be
mixed in an extruder. In a particular embodiment, the HNP
composition comprises an acid copolymer and an additional polymer
component, wherein the additional polymer component is a non-acid
polymer present in an amount of greater than 50 wt %, or an amount
within a range having a lower limit of 50 or 55 or 60 or 65 or 70
and an upper limit of 80 or 85 or 90, based on the combined weight
of the acid copolymer and the non-acid polymer. In another
particular embodiment, the HNP composition comprises an acid
copolymer and an additional polymer component, wherein the
additional polymer component is a non-acid polymer present in an
amount of less than 50 wt %, or an amount within a range having a
lower limit of 10 or 15 or 20 or 25 or 30 and an upper limit of 40
or 45 or 50, based on the combined weight of the acid copolymer and
the non-acid polymer.
[0070] HNP compositions of the present invention, in the neat
(i.e., unfilled) form, preferably have a specific gravity of from
0.95 g/cc to 0.99 g/cc. Any suitable filler, flake, fiber,
particle, or the like, of an organic or inorganic material may be
added to the HNP composition to increase or decrease the specific
gravity, particularly to adjust the weight distribution within the
golf ball, as further disclosed in U.S. Pat. Nos. 6,494,795,
6,547,677, 6,743,123, 7,074,137, and 6,688,991, the entire
disclosures of which are hereby incorporated herein by
reference.
[0071] In a particular embodiment, the HNP composition is selected
from the relatively soft HNP compositions disclosed in U.S. Pat.
No. 7,468,006, the entire disclosure of which is hereby
incorporated herein by reference, and the low modulus HNP
compositions disclosed in U.S. Pat. No. 7,207,903, the entire
disclosure of which is hereby incorporated herein by reference. In
a particular aspect of this embodiment, a sphere formed from the
HNP composition has a compression of 80 or less, or 70 or less, or
65 or less, or 60 or less, or 50 or less, or 40 or less, or 30 or
less, or 20 or less. In another particular aspect of this
embodiment, the HNP composition has a material hardness within a
range having a lower limit of 40 or 50 or 55 Shore C and an upper
limit of 70 or 80 or 87 Shore C, or a material hardness of 55 Shore
D or less, or a material hardness within a range having a lower
limit of 10 or 20 or 30 or 37 or 39 or 40 or 45 Shore D and an
upper limit of 48 or 50 or 52 or 55 or 60 or 80 Shore D. In yet
another particular aspect of this embodiment, the HNP composition
comprises an HNP having a modulus within a range having a lower
limit of 1,000 or 5,000 or 10,000 psi and an upper limit of 17,000
or 25,000 or 28,000 or 30,000 or 35,000 or 45,000 or 50,000 or
55,000 psi, as measured using a standard flex bar according to ASTM
D790-B.
[0072] In another particular embodiment, the HNP composition is
selected from the relatively hard HNP compositions disclosed in
U.S. Pat. No. 7,468,006, the entire disclosure of which is hereby
incorporated herein by reference, and the high modulus HNP
compositions disclosed in U.S. Pat. No. 7,207,903, the entire
disclosure of which is hereby incorporated herein by reference. In
a particular aspect of this embodiment, a sphere formed from the
HNP composition has a compression of 70 or greater, or 80 or
greater, or a compression within a range having a lower limit of 70
or 80 or 90 or 100 and an upper limit of 110 or 130 or 140. In
another particular aspect of this embodiment, the HNP composition
has a material hardness of 35 Shore D or greater, or 45 Shore D or
greater, or a material hardness within a range having a lower limit
of 45 or 50 or 55 or 57 or 58 or 60 or 65 or 70 or 75 Shore D and
an upper limit of 75 or 80 or 85 or 90 or 95 Shore D. In yet
another particular aspect of this embodiment, the HNP composition
comprises an HNP having a modulus within a range having a lower
limit of 25,000 or 27,000 or 30,000 or 40,000 or 45,000 or 50,000
or 55,000 or 60,000 psi and an upper limit of 72,000 or 75,000 or
100,000 or 150,000 psi, as measured using a standard flex bar
according to ASTM D790-B.
[0073] Suitable HNP compositions are further disclosed, for
example, in U.S. Pat. Nos. 6,653,382, 6,756,436, 6,777,472,
6,815,480, 6,894,098, 6,919,393, 6,953,820, 6,994,638, 7,375,151,
the entire disclosures of which are hereby incorporated herein by
reference.
[0074] In a particular embodiment, the HNP composition is formed by
blending an acid polymer, a non-acid polymer, a cation source, and
a fatty acid or metal salt thereof. For purposes of the present
invention, maleic anhydride modified polymers are defined herein as
a non-acid polymer despite having anhydride groups that can
ring-open to the acid form during processing of the polymer to form
the HNP compositions herein. The maleic anhydride groups are
grafted onto a polymer, are present at relatively very low levels,
and are not part of the polymer backbone, as is the case with the
acid polymers, which are exclusively E/X and E/X/Y copolymers of
ethylene and an acid, particularly methacrylic acid and acrylic
acid.
[0075] In a particular aspect of this embodiment, the acid polymer
is selected from ethylene-acrylic acid and ethylene-methacrylic
acid copolymers, optionally containing a softening monomer selected
from n-butyl acrylate and iso-butyl acrylate. The acid polymer
preferably has an acid content with a range having a lower limit of
2 or 10 or 15 or 16 mol % and an upper limit of 20 or 25 or 26 or
30 mol %. Examples of particularly suitable commercially available
acid polymers include, but are not limited to, those given in Table
1 below.
TABLE-US-00001 TABLE 1 Melt Index Softening (2.16 kg, Acid Monomer
190.degree. C., Acid Polymer (wt %) (wt %) g/10 min) Nucrel .RTM.
9-1 methacrylic acid n-butyl acrylate 25 (9.0) (23.5) Nucrel .RTM.
599 methacrylic acid none 450 (10.0) Nucrel .RTM. 960 methyacrylic
acid none 60 (15.0) Nucrel .RTM. 0407 methacrylic acid none 7.5
(4.0) Nucrel .RTM. 0609 methacrylic acid none 9 (6.0) Nucrel .RTM.
1214 methacrylic acid none 13.5 (12.0) Nucrel .RTM. 2906
methacrylic acid none 60 (19.0) Nucrel .RTM. 2940 methacrylic acid
none 395 (19.0) Nucrel .RTM. 30707 acrylic acid none 7 (7.0) Nucrel
.RTM. 31001 acrylic acid none 1.3 (9.5) Nucrel .RTM. AE methacrylic
acid isobutyl acrylate 11 (2.0) (6.0) Nucrel .RTM. 2806 acrylic
acid none 60 (18.0) Nucrel .RTM. 0403 methacrylic acid none 3 (4.0)
Nucrel .RTM. 925 methacrylic acid none 25 (15.0) Escor .RTM. AT-310
acrylic acid methyl acrylate 6 (6.5) (6.5) Escor .RTM. AT-325
acrylic acid methyl acrylate 20 (6.0) (20.0) Escor .RTM. AT-320
acrylic acid methyl acrylate 5 (6.0) (18.0) Escor .RTM. 5070
acrylic acid none 30 (9.0) Escor .RTM. 5100 acrylic acid none 8.5
(11.0) Escor .RTM. 5200 acrylic acid none 38 (15.0) A-C .RTM. 5120
acrylic acid none not reported (15) A-C .RTM. 540 acrylic acid none
not reported (5) A-C .RTM. 580 acrylic acid none not reported (10)
Primacor .RTM. 3150 acrylic acid none 5.8 (6.5) Primacor .RTM. 3330
acrylic acid none 11 (3.0) Primacor .RTM. 5985 acrylic acid none
240 (20.5) Primacor .RTM. 5986 acrylic acid none 300 (20.5)
Primacor .RTM. 5980I acrylic acid none 300 (20.5) Primacor .RTM.
5990I acrylic acid none 1300 (20.0) XUS 60751.17 acrylic acid none
600 (19.8) XUS 60753.02L acrylic acid none 60 (17.0) Nucrel .RTM.
acid polymers are commercially available from E. I. du Pont de
Nemours and Company. Escor .RTM. acid polymers are commercially
available from ExxonMobil Chemical Company. A-C .RTM. acid polymers
are commercially available from Honeywell International Inc.
Primacor .RTM. acid polymers and XUS acid polymers are commercially
available from The Dow Chemical Company.
[0076] In another particular aspect of this embodiment, the
non-acid polymer is an elastomeric polymer. Suitable elastomeric
polymers include, but are not limited to: [0077] (a) ethylene-alkyl
acrylate polymers, particularly polyethylene-butyl acrylate,
polyethylene-methyl acrylate, and polyethylene-ethyl acrylate;
[0078] (b) metallocene-catalyzed polymers; [0079] (c)
ethylene-butyl acrylate-carbon monoxide polymers and ethylene-vinyl
acetate-carbon monoxide polymers; [0080] (d) polyethylene-vinyl
acetates; [0081] (e) ethylene-alkyl acrylate polymers containing a
cure site monomer; [0082] (f) ethylene-propylene rubbers and
ethylene-propylene-diene monomer rubbers; [0083] (g) olefinic
ethylene elastomers, particularly ethylene-octene polymers,
ethylene-butene polymers, ethylene-propylene polymers, and
ethylene-hexene polymers; [0084] (h) styrenic block copolymers;
[0085] (i) polyester elastomers; [0086] (j) polyamide elastomers;
[0087] (k) polyolefin rubbers, particularly polybutadiene,
polyisoprene, and styrene-butadiene rubber; and [0088] (l)
thermoplastic polyurethanes.
[0089] Examples of particularly suitable commercially available
non-acid polymers include, but are not limited to, Lotader.RTM.
ethylene-alkyl acrylate polymers and Lotryl.RTM. ethylene-alkyl
acrylate polymers, and particularly Lotader.RTM. 4210, 4603, 4700,
4720, 6200, 8200, and AX8900 commercially available from Arkema
Corporation; Elvaloy.RTM. AC ethylene-alkyl acrylate polymers, and
particularly AC 1224, AC 1335, AC 2116, AC3117, AC3427, and
AC34035, commercially available from E. I. du Pont de Nemours and
Company; Fusabond.RTM. elastomeric polymers, such as ethylene vinyl
acetates, polyethylenes, metallocene-catalyzed polyethylenes,
ethylene propylene rubbers, and polypropylenes, and particularly
Fusabond.RTM. N525, C190, C250, A560, N416, N493, N614, P614, M603,
E100, E158, E226, E265, E528, and E589, commercially available from
E. I. du Pont de Nemours and Company; Honeywell A-C polyethylenes
and ethylene maleic anhydride copolymers, and particularly A-C
5180, A-C 575, A-C 573, A-C 655, and A-C 395, commercially
available from Honeywell; Nordel.RTM. IP rubber, Elite.RTM.
polyethylenes, Engage.RTM. elastomers, and Amplify.RTM. functional
polymers, and particularly Amplify.RTM. GR 207, GR 208, GR 209, GR
213, GR 216, GR 320, GR 380, and EA 100, commercially available
from The Dow Chemical Company; Enable.RTM. metallocene
polyethylenes, Exact.RTM. plastomers, Vistamaxx.RTM.
propylene-based elastomers, and Vistalon.RTM. EPDM rubber,
commercially available from ExxonMobil Chemical Company;
Starflex.RTM. metallocene linear low density polyethylene,
commercially available from LyondellBasell; Elvaloy.RTM. HP4051,
HP441, HP661 and HP662 ethylene-butyl acrylate-carbon monoxide
polymers and Elvaloy.RTM. 741, 742 and 4924 ethylene-vinyl
acetate-carbon monoxide polymers, commercially available from E. I.
du Pont de Nemours and Company; Evatane.RTM. ethylene-vinyl acetate
polymers having a vinyl acetate content of from 18 to 42%,
commercially available from Arkema Corporation; Elvax.RTM.
ethylene-vinyl acetate polymers having a vinyl acetate content of
from 7.5 to 40%, commercially available from E. I. du Pont de
Nemours and Company; Vamac.RTM. G terpolymer of ethylene,
methylacrylate and a cure site monomer, commercially available from
E. I. du Pont de Nemours and Company; Vistalon.RTM. EPDM rubbers,
commercially available from ExxonMobil Chemical Company;
Kraton.RTM. styrenic block copolymers, and particularly Kraton.RTM.
FG1901GT, FG1924GT, and RP6670GT, commercially available from
Kraton Performance Polymers Inc.; Septon.RTM. styrenic block
copolymers, commercially available from Kuraray Co., Ltd.;
Hytrel.RTM. polyester elastomers, and particularly Hytrel.RTM.
3078, 4069, and 556, commercially available from E. I. du Pont de
Nemours and Company; Riteflex.RTM. polyester elastomers,
commercially available from Celanese Corporation; Pebax.RTM.
thermoplastic polyether block amides, and particularly Pebax.RTM.
2533, 3533, 4033, and 5533, commercially available from Arkema
Inc.; Affinity.RTM. and Affinity.RTM. GA elastomers, Versify.RTM.
ethylene-propylene copolymer elastomers, and Infuse.RTM. olefin
block copolymers, commercially available from The Dow Chemical
Company; Exxelor.RTM.polymer resins, and particularly Exxelor.RTM.
PE 1040, PO 1015, PO 1020, VA 1202, VA 1801, VA 1803, and VA 1840,
commercially available from ExxonMobil Chemical Company; and
Royaltuf.RTM. EPDM, and particularly Royaltuf.RTM.498 maleic
anhydride modified polyolefin based on an amorphous EPDM and
Royaltuf.RTM. 485 maleic anhydride modified polyolefin based on an
semi-crystalline EPDM, commercially available from Chemtura
Corporation.
[0090] Additional examples of particularly suitable commercially
available elastomeric polymers include, but are not limited to,
those given in Table 2 below.
TABLE-US-00002 TABLE 2 Melt Index % Maleic (2.16 kg, 190.degree.
C., % Ester Anhydride g/10 min) Polyethylene Butyl Acrylates
Lotader .RTM. 3210 6 3.1 5 Lotader .RTM. 4210 6.5 3.6 9 Lotader
.RTM. 3410 17 3.1 5 Lotryl .RTM. 17BA04 16-19 0 3.5-4.5 Lotryl
.RTM. 35BA320 33-37 0 260-350 Elvaloy .RTM. AC 3117 17 0 1.5
Elvaloy .RTM. AC 3427 27 0 4 Elvaloy .RTM. AC 34035 35 0 40
Polyethylene Methyl Acrylates Lotader .RTM. 4503 19 0.3 8 Lotader
.RTM. 4603 26 0.3 8 Lotader .RTM. AX 8900 26 8% GMA 6 Lotryl .RTM.
24MA02 23-26 0 1-3 Elvaloy .RTM. AC 12024S 24 0 20 Elvaloy .RTM. AC
1330 30 0 3 Elvaloy .RTM. AC 1335 35 0 3 Elvaloy .RTM. AC 1224 24 0
2 Polyethylene Ethyl Acrylates Lotader .RTM. 6200 6.5 2.8 40
Lotader .RTM. 8200 6.5 2.8 200 Lotader .RTM. LX 4110 5 3.0 5
Lotader .RTM. HX 8290 17 2.8 70 Lotader .RTM. 5500 20 2.8 20
Lotader .RTM. 4700 29 1.3 7 Lotader .RTM. 4720 29 0.3 7 Elvaloy
.RTM. AC 2116 16 0 1
[0091] The acid polymer and non-acid polymer are combined and
reacted with a cation source, such that at least 80% of all acid
groups present are neutralized. The present invention is not meant
to be limited by a particular order for combining and reacting the
acid polymer, non-acid polymer and cation source. In a particular
embodiment, the fatty acid or metal salt thereof is used in an
amount such that the fatty acid or metal salt thereof is present in
the HNP composition in an amount of from 10 wt % to 60 wt %, or
within a range having a lower limit of 10 or 20 or 30 or 40 wt %
and an upper limit of 40 or 50 or 60 wt %, based on the total
weight of the HNP composition. Suitable cation sources and fatty
acids and metal salts thereof are further disclosed above.
[0092] In another particular aspect of this embodiment, the acid
polymer is an ethylene-acrylic acid polymer having an acid content
of 19 wt % or greater, the non-acid polymer is a
metallocene-catalyzed ethylene-butene copolymer, optionally
modified with maleic anhydride, the cation source is magnesium, and
the fatty acid or metal salt thereof is magnesium oleate present in
the composition in an amount of 20 to 50 wt %, based on the total
weight of the composition.
[0093] As discussed above, the composition used to form the inner
core contains a metal material. In one version, the metal material
can constitute the entire inner core. That is, the metal material
comprises 100% of the composition used to make the inner core. The
metal material is preferably in the shape of a solid sphere, for
example, a ball bearing. The metal sphere can be used as the inner
core (center) and a polymeric outer core layer can be disposed
about the metal center. Alternatively, metal fillers, as described
further below, can be dispersed in a polymeric binder to form a
metal-containing composition that can be used to make the inner
core. Relatively heavy-weight metal materials such as, for example,
a metal selected from the group consisting of copper, nickel,
tungsten, brass, steel, magnesium, molybdenum, cobalt, lead, tin,
silver, gold and platinum alloys can be used. Suitable steel
materials include, for example, chrome steel, stainless steel,
carbon steel, and alloys thereof. Alternatively, or in addition to
the heavy metals, relatively light-weight metal materials such as
titanium and aluminum alloys can be used, provided the inner core
layer has the required specific gravity. The metal filler is added
to the composition in a sufficient amount to obtain the desired
specific gravity as discussed further below.
[0094] If the size of the inner core (center) is small and a dense
metal material such as tungsten is being used, then the amount of
tungsten needed to obtain the desired specific gravity will be
relatively low. The weight of such a dense metal material is more
concentrated so a smaller amount of material is needed. On the
other hand, if a low density metal material such as aluminum is
being used, then the amount of aluminum needed to reach the needed
specific gravity will be relatively high. Normally, the metal
filler is present in the composition in an amount with the range of
about 1% to about 60%. Preferably, the metal filler is present in
the composition in an amount of 20 wt. % or less, 15 wt % or less,
or 12 wt % or less, or 10 wt % or less, or 6 wt % or less, or 4 wt
% or less based on weight of polymer in the composition.
[0095] The overall specific gravity of the core structure (inner
core and outer core layers) is preferably at least 1.8 g/cc, more
preferably at least 2.00 g/cc, and most preferably at least 2.50
g/cc. In general, the inner core has a specific gravity of at least
about 1.00 g/cc and is generally within the range of about 1.00 to
about 20.00. Preferably, the inner core has a lower limit of
specific gravity of about 1.10 or 1.20 or 1.50 or 2.00 or 2.50 or
3.50 or 4.00 or 5.00 or 6.00 or 7.00 or 8.00 g/cc and an upper
limit of about 9.00 or 9.50 or 10.00 or 10.50 or 11.00 or 12.00 or
13.00 or 14.00 or 15.00 or 16.00 or 17.00 or 18.00 or 19.00 or
19.50 g/cc. In a preferred embodiment, the inner core has a
specific gravity of about 1.20 to about 5.50 g/cc, more preferably
about 1.25 to about 3.25 g/cc.
[0096] Meanwhile, the outer core layer preferably has a relatively
low specific gravity. Thus, the specific gravity of inner core
layer (SG.sub.inner) is preferably greater than the specific
gravity of the outer core layer (SG.sub.outer). For example, the
outer core layer may have a specific gravity within a range having
a lower limit of about 0.80, 0.90 g/cc, 1.00 or 1.25 or 2.00 or
2.50 or 3.00 or 3.50 or 4.00, 4.25 or 5.00 and an upper limit of
about 6.00 or 6.50 or 7.00 or 7.25 or 8.00 or 8.50 or 9.00 or 9.25
or 10.00 g/cc. In one preferred embodiment, the SG.sub.inter is
preferably greater than the SG.sub.outer by at least 0.5 g/cc, more
preferably 0.75 g/cc or greater, and even more preferably 1.00 g/cc
or greater. In one embodiment, the difference between the
SG.sub.inner and the SG.sub.outer is within the range of about 0.5
g/cc to about 2.0 g/cc.
[0097] Suitable metal fillers that can be added to the polymeric
matrix used to form the inner core preferably have specific gravity
values in the range from about 1.5 to about 19.5, and include, for
example, metal (or metal alloy) powder, metal oxide, metal
stearates, particulates, flakes, and the like, and blends thereof.
Examples of useful metal (or metal alloy) powders include, but are
not limited to, bismuth powder, boron powder, brass powder, bronze
powder, cobalt powder, copper powder, iron powder, molybdenum
powder, nickel powder, stainless steel powder, titanium metal
powder, zirconium oxide powder, aluminum flakes, tungsten metal
powder, beryllium metal powder, zinc metal powder, or tin metal
powder. Examples of metal oxides include, but are not limited to,
zinc oxide, iron oxide, aluminum oxide, titanium dioxide, magnesium
oxide, zirconium oxide, and tungsten trioxide.
Outer Core Composition
[0098] As discussed above, the inner core may be formed from
metal-filled thermoset or thermoplastic materials and is preferably
formed from a metal-filled thermoset rubber. Likewise, the outer
core layer may be formed from thermoset or thermoplastic
materials.
[0099] In one embodiment, the outer core layer is formed from a
thermoset rubber composition. That is, the same rubber composition
(except for the metal fillers used to adjust the specific gravity
to the desired level) that is optionally used to form the inner
core also may be used to form the outer core layer. The rubber
compositions may contain conventional additives such as
free-radical initiators, cross-linking agents, soft and fast
agents, and antioxidants, and the composition may be cured using
conventional systems as described further below. However, the
specific gravity of the inner core and outer core layers will be
different; thus, the concentration and/or type of metal fillers
used in the respective compositions to adjust the specific gravity
will be different. In one embodiment, the outer core layer may not
even contain any metal materials.
[0100] In another embodiment, the outer core layer may contain a
relatively small concentration of metal fillers, while the inner
core contains a large concentration of metal fillers. In another
embodiment, the outer core layer is formed from a thermoplastic
composition. That is, the same thermoplastic composition (except
for the metal fillers used to adjust the specific gravity to the
desired level) that is used to form the inner core also may be used
to form the outer core layer. Thus, each of the inner and outer
core layers may be formed from a partially or highly neutralized
ethylene acid copolymer composition. However, the specific gravity
of the inner core and outer core layers will be different; thus,
the concentration and/or type of metal fillers used in the
respective compositions to adjust the specific gravity will be
different. In one embodiment, the outer core layer may not even
contain any metal materials. In another embodiment, the outer core
layer may contain a relatively small concentration of metal
fillers, while the inner core contains a large concentration of
metal fillers.
[0101] Preferably, the outer core layer is formed from an ionomer
composition comprising an ethylene acid copolymer containing acid
groups that are at least partially neutralized. As discussed
further below, preferably, the neutralization level is greater than
70%, more preferably at least 90% and even more preferably at least
100%. Suitable ethylene acid copolymers that may be used to form
the compositions of this invention are generally referred to as
copolymers of ethylene; C.sub.3 to C.sub.8
.alpha.,.beta.-ethylenically unsaturated mono- or dicarboxylic
acid; and optional softening monomer. Copolymers may include,
without limitation, ethylene acid copolymers, such as
ethylene/(meth)acrylic acid, ethylene/(meth)acrylic acid/maleic
anhydride, ethylene/(meth)acrylic acid/maleic acid mono-ester,
ethylene/maleic acid, ethylene/maleic acid mono-ester,
ethylene/(meth)acrylic acid/n-butyl (meth)acrylate,
ethylene/(meth)acrylic acid/iso-butyl (meth)acrylate,
ethylene/(meth)acrylic acid/methyl (meth)acrylate,
ethylene/(meth)acrylic acid/ethyl (meth)acrylate terpolymers, and
the like. The term, "copolymer," as used herein, includes polymers
having two types of monomers, those having three types of monomers,
and those having more than three types of monomers. Preferred
.alpha.,.beta.-ethylenically unsaturated mono- or dicarboxylic
acids are (meth) acrylic acid, ethacrylic acid, maleic acid,
crotonic acid, fumaric acid, itaconic acid. (Meth) acrylic acid is
most preferred. As used herein, "(meth) acrylic acid" means
methacrylic acid and/or acrylic acid. Likewise, "(meth)acrylate"
means methacrylate and/or acrylate.
[0102] When a softening monomer is included, such copolymers are
referred to herein as E/X/Y-type copolymers, wherein E is ethylene;
X is a C.sub.3 to C.sub.8 .alpha.,.beta.-ethylenically unsaturated
mono- or dicarboxylic acid; and Y is a softening monomer. The
softening monomer is typically an alkyl (meth)acrylate, wherein the
alkyl groups have from 1 to 8 carbon atoms. Preferred E/X/Y-type
copolymers are those wherein X is (meth) acrylic acid and/or Y is
selected from (meth)acrylate, n-butyl (meth)acrylate, isobutyl
(meth)acrylate, methyl (meth)acrylate, and ethyl (meth) acrylate.
More preferred E/X/Y-type copolymers are ethylene/(meth) acrylic
acid/n-butyl acrylate, ethylene/(meth) acrylic acid/methyl
acrylate, and ethylene/(meth) acrylic acid/ethyl acrylate.
[0103] The amount of ethylene in the acid copolymer is typically at
least 15 wt. %, preferably at least 25 wt. %, more preferably least
40 wt. %, and even more preferably at least 60 wt. %, based on
total weight of the copolymer. The amount of C.sub.3 to C.sub.8
.alpha.,.beta.-ethylenically unsaturated mono- or dicarboxylic acid
in the acid copolymer is typically from 1 wt. % to 35 wt. %,
preferably from 5 wt. % to 30 wt. %, more preferably from 5 wt. %
to 25 wt. %, and even more preferably from 10 wt. % to 20 wt. %,
based on total weight of the copolymer. The amount of optional
softening comonomer in the acid copolymer is typically from 0 wt. %
to 50 wt. %, preferably from 5 wt. % to 40 wt. %, more preferably
from 10 wt. % to 35 wt. %, and even more preferably from 20 wt. %
to 30 wt. %, based on total weight of the copolymer. "Low acid" and
"high acid" ionomeric polymers, as well as blends of such ionomers,
may be used. In general, low acid ionomers are considered to be
those containing 16 wt. % or less of acid moieties, whereas high
acid ionomers are considered to be those containing greater than 16
wt. % of acid moieties.
[0104] The acidic groups in the copolymeric ionomers are partially
or totally neutralized with a cation source. Suitable cation
sources include metal cations and salts thereof, organic amine
compounds, ammonium, and combinations thereof. Preferred cation
sources are metal cations and salts thereof, wherein the metal is
preferably lithium, sodium, potassium, magnesium, calcium, barium,
lead, tin, zinc, aluminum, manganese, nickel, chromium, copper, or
a combination thereof. The metal cation salts provide the cations
capable of neutralizing (at varying levels) the carboxylic acids of
the ethylene acid copolymer and fatty acids, if present, as
discussed further below. These include, for example, the sulfate,
carbonate, acetate, oxide, or hydroxide salts of lithium, sodium,
potassium, magnesium, calcium, barium, lead, tin, zinc, aluminum,
manganese, nickel, chromium, copper, or a combination thereof.
Preferred metal cation salts are calcium and magnesium-based salts.
High surface area cation particles such as micro and nano-scale
cation particles are preferred. The amount of cation used in the
composition is readily determined based on desired level of
neutralization.
[0105] For example, ionomeric resins having acid groups that are
neutralized from about 10 percent to about 100 percent may be used.
In one ionomer composition, the acid groups are partially
neutralized. That is, the neutralization level is from about 10% to
about 70%, more preferably 20% to 60%, and most preferably 30 to
50%. These ionomer compositions, containing acid groups neutralized
to 70% or less, may be referred to ionomers having relatively low
neutralization levels.
[0106] On the other hand, the ionomer composition may contain acid
groups that are highly or fully-neutralized. These highly
neutralized polymers (HNPs) are preferred for forming at least one
core layer in the present invention. In these HNPs, the
neutralization level is greater than 70%, preferably at least 90%
and even more preferably at least 100%. In another embodiment, an
excess amount of neutralizing agent, that is, an amount greater
than the stoichiometric amount needed to neutralize the acid
groups, may be used. That is, the acid groups may be neutralized to
100% or greater, for example 110% or 120% or greater. In one
preferred embodiment, a high acid ethylene acid copolymer
containing about 19 to 20 wt. % methacrylic or acrylic acid is
neutralized with zinc and sodium cations to a 95% neutralization
level.
[0107] "Ionic plasticizers" such as organic acids or salts of
organic acids, particularly fatty acids, may be added to the
ionomer resin if needed. Such ionic plasticizers are used to make
conventional ionomer composition more processable as described in
Rajagopalan et al., U.S. Pat. No. 6,756,436, the disclosure of
which is hereby incorporated by reference. In one preferred
embodiment, the thermoplastic ionomer composition, containing acid
groups neutralized to 70% or less, does not include a fatty acid or
salt thereof, or any other ionic plasticizer. On the other hand,
the thermoplastic ionomer composition, containing acid groups
neutralized to greater than 70%, includes an ionic plasticizer,
particularly a fatty acid or salt thereof. For example, the ionic
plasticizer may be added in an amount of 0.5 to 10 pph, more
preferably 1 to 5 pph. The organic acids may be aliphatic, mono- or
multi-functional (saturated, unsaturated, or multi-unsaturated)
organic acids. Salts of these organic acids may also be employed.
Suitable fatty acid salts include, for example, metal stearates,
laureates, oleates, palmitates, pelargonates, and the like. For
example, fatty acid salts such as zinc stearate, calcium stearate,
magnesium stearate, barium stearate, and the like can be used. The
salts of fatty acids are generally fatty acids neutralized with
metal ions. The metal cation salts provide the cations capable of
neutralizing (at varying levels) the carboxylic acid groups of the
fatty acids. Examples include the sulfate, carbonate, acetate and
hydroxide salts of metals such as barium, lithium, sodium, zinc,
bismuth, chromium, cobalt, copper, potassium, strontium, titanium,
tungsten, magnesium, cesium, iron, nickel, silver, aluminum, tin,
or calcium, and blends thereof. It is preferred the organic acids
and salts be relatively non-migratory (they do not bloom to the
surface of the polymer under ambient temperatures) and non-volatile
(they do not volatilize at temperatures required for
melt-blending).
[0108] As noted above, the final ionomer compositions may contain
additional materials such as, for example, a small amount of ionic
plasticizer, which is particularly effective at improving the
processability of highly-neutralized ionomers. For example, the
ionic plasticizer may be added in an amount of 0.5 to 10 pph, more
preferably 1 to 5 pph. In addition to the fatty acids and salts of
fatty acids discussed above, other suitable ionic plasticizers
include, for example, polyethylene glycols, waxes, bis-stearamides,
minerals, and phthalates. In another embodiment, an amine or
pyridine compound is used, preferably in addition to a metal
cation. Suitable examples include, for example, ethylamine,
methylamine, diethylamine, tert-butylamine, dodecylamine, and the
like.
[0109] The ionomer compositions may contain a wide variety of
fillers and some of these fillers may be used to adjust the
specific gravity of the composition as needed. High surface-area
fillers that have an affinity for the acid groups in ionomer may be
used. In particular, fillers such as particulate, fibers, or flakes
having cationic nature such that they may also contribute to the
neutralization of the ionomer are suitable. For example, aluminum
oxide, zinc oxide, tin oxide, barium sulfate, zinc sulfate, calcium
oxide, calcium carbonate, zinc carbonate, barium carbonate,
tungsten, tungsten carbide, and lead silicate fillers may be used.
Also, silica, fumed silica, and precipitated silica, such as those
sold under the tradename HISIL from PPG Industries, carbon black,
carbon fibers, and nano-scale materials such as nanotubes,
nanoflakes, nanofillers, and nanoclays may be used. Other additives
and fillers include, but are not limited to, chemical blowing and
foaming agents, optical brighteners, coloring agents, fluorescent
agents, whitening agents, UV absorbers, light stabilizers,
defoaming agents, processing aids, antioxidants, stabilizers,
softening agents, fragrance components, plasticizers, impact
modifiers, titanium dioxide, acid copolymer wax, surfactants,
rubber regrind (recycled core material), clay, mica, talc, glass
flakes, milled glass, and mixtures thereof. Suitable additives are
more fully described in, for example, Rajagopalan et al., U.S.
Patent Application Publication No. 2003/0225197, the entire
disclosure of which is hereby incorporated herein by reference. In
a particular embodiment, the total amount of additive(s) and
filler(s) present in the final thermoplastic ionomeric composition
is 15 wt % or less, or 12 wt % or less, or 10 wt % or less, or 9 wt
% or less, or 6 wt % or less, or 5 wt % or less, or 4 wt % or less,
or 3 wt % or less, based on the total weight of the ionomeric
composition.
[0110] The ethylene acid copolymer is used in an amount of at least
about 5% by weight based on total weight of composition and is
generally present in an amount of about 5% to about 100%, or an
amount within a range having a lower limit of 5% or 10% or 20% or
30% or 40% or 50% and an upper limit of 55% or 60% or 70% or 80% or
90% or 95% or 100%. Preferably, the concentration of ethylene acid
copolymer is about 40 to about 95 weight percent. Other suitable
thermoplastic polymers that may be used to form the outer core
structure include, but are not limited to, the following polymers
(including homopolymers, copolymers, and derivatives thereof):
[0111] (a) polyesters, particularly those modified with a
compatibilizing group such as sulfonate or phosphonate, including
modified poly(ethylene terephthalate), modified poly(butylene
terephthalate), modified poly(propylene terephthalate), modified
poly(trimethylene terephthalate), modified poly(ethylene
naphthenate), and those disclosed in U.S. Pat. Nos. 6,353,050,
6,274,298, and 6,001,930, the entire disclosures of which are
hereby incorporated herein by reference, and blends of two or more
thereof;
[0112] (b) polyamides, polyamide-ethers, and polyamide-esters, and
those disclosed in U.S. Pat. Nos. 6,187,864, 6,001,930, and
5,981,654, the entire disclosures of which are hereby incorporated
herein by reference, and blends of two or more thereof;
[0113] (c) polyurethanes, polyureas, polyurethane-polyurea hybrids,
and blends of two or more thereof;
[0114] (d) fluoropolymers, such as those disclosed in U.S. Pat.
Nos. 5,691,066, 6,747,110 and 7,009,002, the entire disclosures of
which are hereby incorporated herein by reference, and blends of
two or more thereof;
[0115] (e) polystyrenes, such as poly(styrene-co-maleic anhydride),
acrylonitrile-butadiene-styrene, poly(styrene sulfonate),
polyethylene styrene, and blends of two or more thereof;
[0116] (f) polyvinyl chlorides and grafted polyvinyl chlorides, and
blends of two or more thereof;
[0117] (g) polycarbonates, blends of
polycarbonate/acrylonitrile-butadiene-styrene, blends of
polycarbonate/polyurethane, blends of polycarbonate/polyester, and
blends of two or more thereof;
[0118] (h) polyethers, such as polyarylene ethers, polyphenylene
oxides, block copolymers of alkenyl aromatics with vinyl aromatics
and polyamicesters, and blends of two or more thereof;
[0119] (i) polyimides, polyetherketones, polyamideimides, and
blends of two or more thereof; and
[0120] (j) polycarbonate/polyester copolymers and blends.
[0121] These thermoplastic polymers may be used by and in
themselves to form the outer core, or blends of thermoplastic
polymers including the above-described polymers and ethylene acid
copolymer ionomers may be used. It also is recognized that the
ionomer compositions may contain a blend of two or more ionomers.
For example, the composition may contain a 50/50 wt. % blend of two
different highly-neutralized ethylene/methacrylic acid copolymers.
In another version, the composition may contain a blend of one or
more ionomers and a maleic anhydride-grafted non-ionomeric polymer.
The non-ionomeric polymer may be a metallocene-catalyzed polymer.
In another version, the composition contains a blend of a
highly-neutralized ethylene/methacrylic acid copolymer and a maleic
anhydride-grafted metallocene-catalyzed polyethylene. In yet
another version, the composition contains a material selected from
the group consisting of highly-neutralized ionomers optionally
blended with a maleic anhydride-grafted non-ionomeric polymer;
polyester elastomers; polyamide elastomers; and combinations of two
or more thereof.
[0122] In a particular embodiment, the outer core layer is formed
from a highly neutralized composition formed by blending an acid
polymer, a non-acid polymer, a cation source, and a fatty acid or
metal salt thereof, as disclosed above for use in forming the inner
core layer.
[0123] As discussed above, the specific gravity of inner core layer
(SG.sub.inner) is preferably greater than the specific gravity of
the outer core layer (SG.sub.outer). In general, the specific
gravities of the respective pieces of an object affect the Moment
of Inertia (MOI) of the object. In general, the Moment of Inertia
of a ball (or other object) about a given axis refers to how
difficult it is to change the ball's angular motion about that
axis. If the ball's mass is concentrated towards the center (the
center piece has a higher specific gravity than the outer piece),
less force is required to change its rotational rate, and the ball
has a relatively low Moment of Inertia. In such balls, most of the
mass is located close to the ball's axis of rotation and less force
is needed to generate spin. Thus, the ball has a generally high
spin rate. Conversely, if the ball's mass is concentrated towards
the outer surface (the outer piece has a higher specific gravity
than the center piece), more force is required to change its
rotational rate, and the ball has a relatively high Moment of
Inertia. That is, in such balls, most of the mass is located away
from the ball's axis of rotation and more force is needed to
generate spin. Such balls have a generally low spin rate.
[0124] The golf balls of this invention having the above-described
core constructions show both good resiliency and spin control. The
resulting ball has a relatively high Coefficient of Restitution
(COR) allowing it to reach a high velocity when struck by a golf
club. Thus, the ball tends to travel a long distance and this is
particularly important for driver shots off the tee. At the same
time, the ball has a soft touch and feel. Thus, the golfer has
better control over the ball which is particularly important when
making approach shots using irons near the green. The golfer can
hit the ball with a soft touch so that it drops and stops quickly
on the green. Furthermore, professional and highly skilled
recreational golfers can place a back-spin on the ball for even
better accuracy and shot-control. For such golfers, the right
amount of spin and touch can be placed on the ball easily. The ball
is more playable and the golfer has more comfort playing with such
a ball. The golfer can hit the ball so that it flies the correct
distance while maintaining control over flight trajectory, spin,
and placement.
[0125] More particularly, as described in Sullivan, U.S. Pat. No.
6,494,795 and Ladd et al., U.S. Pat. No. 7,651,415, the formula for
the Moment of Inertia for a sphere through any diameter is given in
the CRC Standard Mathematical Tables, 24th Edition, 1976 at 20
(hereinafter CRC reference). The term, "specific gravity" as used
herein, has its ordinary and customary meaning, that is, the ratio
of the density of a substance to the density of water at 4.degree.
C., and the density of water at this temperature is 1 g/cm.sup.3.
The specific gravity may be measured according to ASTM test
specification ASTM D-792-98. In addition, the cores of this
invention typically have a COR of about 0.75 or greater; and
preferably about 0.80 or greater. The compression of the core
preferably is about 50 to about 130 and more preferably in the
range of about 70 to about 110.
Curing of Rubber Composition
[0126] The rubber compositions of this invention may be cured using
conventional curing processes. Suitable curing processes include,
for example, peroxide-curing, sulfur-curing, high-energy radiation,
and combinations thereof. Preferably, the rubber composition
contains a free-radical initiator selected from organic peroxides,
high energy radiation sources capable of generating free-radicals,
and combinations thereof. In one preferred version, the rubber
composition is peroxide-cured. Suitable organic peroxides include,
but are not limited to, dicumyl peroxide;
n-butyl-4,4-di(t-butylperoxy) valerate;
1,1-di(t-butylperoxy)3,3,5-trimethylcyclohexane;
2,5-dimethyl-2,5-di(t-butylperoxy) hexane; di-t-butyl peroxide;
di-t-amyl peroxide; t-butyl peroxide; t-butyl cumyl peroxide;
2,5-dimethyl-2,5-di(t-butylperoxy)hexyne-3;
di(2-t-butyl-peroxyisopropyl)benzene; dilauroyl peroxide; dibenzoyl
peroxide; t-butyl hydroperoxide; and combinations thereof. In a
particular embodiment, the free radical initiator is dicumyl
peroxide, including, but not limited to Perkadox.RTM. BC,
commercially available from Akzo Nobel. Peroxide free-radical
initiators are generally present in the rubber composition in an
amount of at least 0.05 parts by weight per 100 parts of the total
rubber, or an amount within the range having a lower limit of 0.05
parts or 0.1 parts or 1 part or 1.25 parts or 1.5 parts or 2.5
parts or 5 parts by weight per 100 parts of the total rubbers, and
an upper limit of 2.5 parts or 3 parts or 5 parts or 6 parts or 10
parts or 15 parts by weight per 100 parts of the total rubber.
Concentrations are in parts per hundred (phr) unless otherwise
indicated. As used herein, the term, "parts per hundred," also
known as "phr" or "pph" is defined as the number of parts by weight
of a particular component present in a mixture, relative to 100
parts by weight of the polymer component. Mathematically, this can
be expressed as the weight of an ingredient divided by the total
weight of the polymer, multiplied by a factor of 100.
[0127] The rubber compositions may further include a reactive
cross-linking co-agent. Suitable co-agents include, but are not
limited to, metal salts of unsaturated carboxylic acids having from
3 to 8 carbon atoms; unsaturated vinyl compounds and polyfunctional
monomers (e.g., trimethylolpropane trimethacrylate); phenylene
bismaleimide; and combinations thereof. Particular examples of
suitable metal salts include, but are not limited to, one or more
metal salts of acrylates, diacrylates, methacrylates, and
dimethacrylates, wherein the metal is selected from magnesium,
calcium, zinc, aluminum, lithium, and nickel. In a particular
embodiment, the co-agent is selected from zinc salts of acrylates,
diacrylates, methacrylates, and dimethacrylates. In another
particular embodiment, the agent is zinc diacrylate (ZDA). When the
co-agent is zinc diacrylate and/or zinc dimethacrylate, the
co-agent is typically included in the rubber composition in an
amount within the range having a lower limit of 1 or 5 or 10 or 15
or 19 or 20 parts by weight per 100 parts of the total rubber, and
an upper limit of 24 or 25 or 30 or 35 or 40 or 45 or 50 or 60
parts by weight per 100 parts of the base rubber.
[0128] Radical scavengers such as a halogenated organosulfur,
organic disulfide, or inorganic disulfide compounds may be added to
the rubber composition. These compounds also may function as "soft
and fast agents." As used herein, "soft and fast agent" means any
compound or a blend thereof that is capable of making a core: 1)
softer (having a lower compression) at a constant "coefficient of
restitution" (COR); and/or 2) faster (having a higher COR at equal
compression), when compared to a core equivalently prepared without
a soft and fast agent. Preferred halogenated organosulfur compounds
include, but are not limited to, pentachlorothiophenol (PCTP) and
salts of PCTP such as zinc pentachlorothiophenol (ZnPCTP). Using
PCTP and ZnPCTP in golf ball inner cores helps produce softer and
faster inner cores. The PCTP and ZnPCTP compounds help increase the
resiliency and the coefficient of restitution of the core. In a
particular embodiment, the soft and fast agent is selected from
ZnPCTP, PCTP, ditolyl disulfide, diphenyl disulfide, dixylyl
disulfide, 2-nitroresorcinol, and combinations thereof.
[0129] As discussed above, the compositions of this invention are
formulated to have specific gravity levels so that they can be used
to form certain core components of the golf ball. In addition to
the metal fillers discussed above, the rubber compositions may
contain other additives. Examples of useful fillers include but are
not limited to, carbonaceous materials such as graphite and carbon
black. graphite fibers, precipitated hydrated silica, clay, talc,
glass fibers, aramid fibers, mica, calcium metasilicate, barium
sulfate, zinc sulfide, silicates, diatomaceous earth, calcium
carbonate, magnesium carbonate, rubber regrind (which is recycled
uncured rubber material which is mixed and ground), cotton flock,
natural bitumen, cellulose flock, and leather fiber. Micro balloon
fillers such as glass and ceramic, and fly ash fillers can also be
used.
[0130] In a particular aspect of this embodiment, the rubber
composition includes filler(s) selected from carbon black,
nanoclays (e.g., Cloisite.RTM. and Nanofil.RTM. nanoclays,
commercially available from Southern Clay Products, Inc., and
Nanomax.RTM. and Nanomer.RTM. nanoclays, commercially available
from Nanocor, Inc.), talc (e.g., Luzenac HAR.RTM. high aspect ratio
talcs, commercially available from Luzenac America, Inc.), glass
(e.g., glass flake, milled glass, and microglass), mica and
mica-based pigments (e.g., Iriodin.RTM. pearl luster pigments,
commercially available from The Merck Group), and combinations
thereof.
[0131] In addition, the rubber compositions may include
antioxidants to prevent the breakdown of the elastomers. Also,
processing aids such as high molecular weight organic acids and
salts thereof may be added to the composition. Suitable organic
acids are aliphatic organic acids, aromatic organic acids,
saturated mono-functional organic acids, unsaturated monofunctional
organic acids, multi-unsaturated mono-functional organic acids, and
dimerized derivatives thereof. Particular examples of suitable
organic acids include, but are not limited to, caproic acid,
caprylic acid, capric acid, lauric acid, stearic acid, behenic
acid, erucic acid, oleic acid, linoleic acid, myristic acid,
benzoic acid, palmitic acid, phenylacetic acid, naphthalenoic acid,
and dimerized derivatives thereof. The organic acids are aliphatic,
mono-functional (saturated, unsaturated, or multi-unsaturated)
organic acids. Salts of these organic acids may also be employed.
The salts of organic acids include the salts of barium, lithium,
sodium, zinc, bismuth, chromium, cobalt, copper, potassium,
strontium, titanium, tungsten, magnesium, cesium, iron, nickel,
silver, aluminum, tin, or calcium, salts of fatty acids,
particularly stearic, behenic, erucic, oleic, linoelic or dimerized
derivatives thereof. It is preferred that the organic acids and
salts of the present invention be relatively non-migratory (they do
not bloom to the surface of the polymer under ambient temperatures)
and non-volatile (they do not volatilize at temperatures required
for melt-blending).
[0132] Other ingredients such as accelerators (for example, tetra
methylthiuram), processing aids, dyes and pigments, wetting agents,
surfactants, plasticizers, coloring agents, fluorescent agents,
chemical blowing and foaming agents, defoaming agents, stabilizers,
softening agents, impact modifiers, antioxidants, antiozonants, as
well as other additives known in the art may be added to the rubber
composition.
Cover Structure
[0133] The golf ball cores of this invention may be enclosed with
one or more cover layers. In one version, the golf ball includes a
multi-layered cover comprising inner and outer cover layers. The
inner cover layer is preferably formed from a composition
comprising an ionomer or a blend of two or more ionomers that helps
impart hardness to the ball. In a particular embodiment, the inner
cover layer is formed from a composition comprising a high acid
ionomer. A particularly suitable high acid ionomer is Surlyn
8150.RTM. (DuPont). Surlyn 8150.RTM. is a copolymer of ethylene and
methacrylic acid, having an acid content of 19 wt %, which is 45%
neutralized with sodium. In another particular embodiment, the
inner cover layer is formed from a composition comprising a high
acid ionomer and a maleic anhydride-grafted non-ionomeric polymer.
A particularly suitable maleic anhydride-grafted polymer is
Fusabond 525D.RTM. (DuPont). Fusabond 525D.RTM. is a maleic
anhydride-grafted, metallocene-catalyzed ethylene-butene copolymer
having about 0.9 wt % maleic anhydride grafted onto the copolymer.
A particularly preferred blend of high acid ionomer and maleic
anhydride-grafted polymer is 84 wt %/16 wt % blend of Surlyn
8150.RTM. and Fusabond 525D.RTM.. Blends of high acid ionomers with
maleic anhydride-grafted polymers are further disclosed, for
example, in U.S. Pat. Nos. 6,992,135 and 6,677,401, the entire
disclosures of which are hereby incorporated herein by
reference.
[0134] The inner cover layer also may be formed from a composition
comprising a 50/45/5 blend of Surlyn.RTM. 8940/Surlyn.RTM.
9650/Nucrel.RTM. 960, and, in a particularly preferred embodiment,
the composition has a material hardness of from 80 to 85 Shore C.
In yet another version, the inner cover layer is formed from a
composition comprising a 50/25/25 blend of Surlyn.RTM.
8940/Surlyn.RTM. 9650/Surlyn.RTM. 9910, preferably having a
material hardness of about 90 Shore C. The inner cover layer also
may be formed from a composition comprising a 50/50 blend of
Surlyn.RTM. 8940/Surlyn.RTM. 9650, preferably having a material
hardness of about 86 Shore C. A composition comprising a 50/50
blend of Surlyn.RTM. 8940 and Surlyn.RTM. 7940 also may be used.
Surlyn.RTM. 8940 is an E/MAA copolymer in which the MAA acid groups
have been partially neutralized with sodium ions. Surlyn.RTM. 9650
and Surlyn.RTM. 9910 are two different grades of E/MAA copolymer in
which the MAA acid groups have been partially neutralized with zinc
ions. Nucrel.RTM. 960 is an E/MAA copolymer resin nominally made
with 15 wt % methacrylic acid.
[0135] A wide variety of materials may be used for forming the
outer cover including, for example, polyurethanes; polyureas;
copolymers, blends and hybrids of polyurethane and polyurea;
olefin-based copolymer ionomer resins (for example, Surlyn.RTM.
ionomer resins and DuPont HPF.RTM. 1000 and HPF.RTM. 2000,
commercially available from DuPont; 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.); polyethylene, including, for example, low density
polyethylene, linear low density polyethylene, and high density
polyethylene; polypropylene; rubber-toughened olefin polymers; acid
copolymers, for example, poly(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; copolymers of ethylene and vinyl acetates;
copolymers of ethylene and methyl acrylates; polyvinyl chloride
resins; polyamides, poly(amide-ester) elastomers, and graft
copolymers of ionomer and polyamide including, for example,
Pebax.RTM. thermoplastic polyether block amides, commercially
available from Arkema Inc; cross-linked trans-polyisoprene and
blends thereof; polyester-based thermoplastic elastomers, such as
Hytrel.RTM., commercially available from DuPont or RiteFlex.RTM.,
commercially available from Ticona Engineering Polymers;
polyurethane-based thermoplastic elastomers, such as
Elastollan.RTM., commercially available from BASF; synthetic or
natural vulcanized rubber; and combinations thereof. Castable
polyurethanes, polyureas, and hybrids of polyurethanes-polyureas
are particularly desirable because these materials can be used to
make a golf ball having high resiliency and a soft feel. By the
term, "hybrids of polyurethane and polyurea," it is meant to
include copolymers and blends thereof.
[0136] Polyurethanes, polyureas, and blends, copolymers, 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.
[0137] The inner cover layer preferably has a material hardness
within a range having a lower limit of 70 or 75 or 80 or 82 Shore C
and an upper limit of 85 or 86 or 90 or 92 Shore C. The thickness
of the intermediate layer is preferably within a range having a
lower limit of 0.010 or 0.015 or 0.020 or 0.030 inches and an upper
limit of 0.035 or 0.045 or 0.080 or 0.120 inches. The outer cover
layer preferably has a material hardness of 85 Shore C or less. The
thickness of the outer cover layer is preferably within a range
having a lower limit of 0.010 or 0.015 or 0.025 inches and an upper
limit of 0.035 or 0.040 or 0.055 or 0.080 inches. Methods for
measuring hardness of the layers in the golf ball are described in
further detail below.
[0138] As discussed above, the core structure of this invention may
be enclosed with one or more cover layers. In one embodiment, a
multi-layered cover comprising inner and outer cover layers is
formed, where the inner cover layer has a thickness of about 0.01
inches to about 0.06 inches, more preferably about 0.015 inches to
about 0.040 inches, and most preferably about 0.02 inches to about
0.035 inches. In this version, the inner cover layer is formed from
a partially- or fully-neutralized ionomer having a Shore D hardness
of greater than about 55, more preferably greater than about 60,
and most preferably greater than about 65. The outer cover layer,
in this embodiment, preferably has a thickness of about 0.015
inches to about 0.055 inches, more preferably about 0.02 inches to
about 0.04 inches, and most preferably about 0.025 inches to about
0.035 inches, with a hardness of about Shore D 80 or less, more
preferably 70 or less, and most preferably about 60 or less. The
inner cover layer is harder than the outer cover layer in this
version. A preferred outer cover layer is a castable or reaction
injection molded polyurethane, polyurea or copolymer, blend, or
hybrid thereof having a Shore D hardness of about 40 to about 50.
In another multi-layer cover, dual-core embodiment, the outer cover
and inner cover layer materials and thickness are the same but, the
hardness range is reversed, that is, the outer cover layer is
harder than the inner cover layer. For this harder outer
cover/softer inner cover embodiment, the ionomer resins disclosed
above preferably would be used as the outer cover material.
Golf Ball Construction
[0139] The solid cores for the golf balls of this invention may be
made using any suitable conventional technique such as, for
example, compression or injection molding. Typically, the inner
core is formed by compression molding a slug of the uncured or
lightly cured polybutadiene rubber material into a spherical
structure. The outer core, which surrounds the inner core, is
formed by molding a composition over the inner core. Compression or
injection molding techniques may be used. Then, the intermediate
and/or cover layers are applied. Prior to this step, the core
structure may be surface-treated to increase the adhesion between
its outer surface and the next layer that will be applied over the
core. Such surface-treatment may include mechanically or
chemically-abrading the outer surface of the core. For example, the
core may be subjected to corona-discharge, plasma-treatment,
silane-dipping, or other treatment methods known to those in the
art.
[0140] The cover layers are formed over the core or ball
subassembly (the core structure and any intermediate layers
disposed about the core) using a suitable technique such as, for
example, compression-molding, flip-molding, injection-molding,
retractable pin injection-molding, reaction injection-molding
(RIM), liquid injection-molding, casting, spraying, powder-coating,
vacuum-forming, flow-coating, dipping, spin-coating, and the like.
Preferably, each cover layer is separately formed over the ball
subassembly. For example, an ethylene acid copolymer ionomer
composition may be injection-molded to produce half-shells.
Alternatively, the ionomer composition can be placed into a
compression mold and molded under sufficient pressure, temperature,
and time to produce the hemispherical shells. The smooth-surfaced
hemispherical shells are then placed around the ball subassembly in
a compression mold. Under sufficient heating and pressure, the
shells fuse together to form an inner cover layer that surrounds
the subassembly. In another method, the ionomer composition is
injection-molded directly onto the core using retractable pin
injection molding. An outer cover layer comprising a polyurethane
or polyurea composition may be formed by using a casting
process.
[0141] For example, in one version of the casting process, a liquid
mixture of reactive polyurethane prepolymer and chain-extender
(curing agent) is poured into lower and upper mold cavities. Then,
the golf ball subassembly is lowered at a controlled speed into the
reactive mixture. Ball suction cups can hold the ball subassembly
in place via reduced pressure or partial vacuum. After sufficient
gelling of the reactive mixture (typically about 4 to about 12
seconds), the vacuum is removed and the intermediate ball is
released into the mold cavity. Then, the upper mold cavity is mated
with the lower mold cavity under sufficient pressure and heat. An
exothermic reaction occurs when the polyurethane prepolymer and
chain extender are mixed and this continues until the cover
material encapsulates and solidifies around the ball subassembly.
Finally, the molded balls are cooled in the mold and removed when
the molded cover is hard enough so that it can be handled without
deformation.
[0142] After the golf balls have been removed from the mold, they
may be subjected to finishing steps such as flash-trimming,
surface-treatment, marking, coating, and the like using techniques
known in the art. For example, in traditional white-colored golf
balls, the white-pigmented cover may be surface-treated using a
suitable method such as, for example, corona, plasma, or
ultraviolet (UV) light-treatment. Then, indicia such as trademarks,
symbols, logos, letters, and the like may be printed on the ball's
cover using pad-printing, ink-jet printing, dye-sublimation, or
other suitable printing methods. Clear surface coatings (for
example, primer and top-coats), which may contain a fluorescent
whitening agent, are applied to the cover. The resulting golf ball
has a glossy and durable surface finish.
[0143] In another finishing process, the golf balls are painted
with one or more paint coatings. For example, white primer paint
may be applied first to the surface of the ball and then a white
top-coat of paint may be applied over the primer. Of course, the
golf ball may be painted with other colors, for example, red, blue,
orange, and yellow. As noted above, markings such as trademarks and
logos may be applied to the painted cover of the golf ball.
Finally, a clear surface coating may be applied to the cover to
provide a shiny appearance and protect any logos and other markings
printed on the ball.
[0144] Different ball constructions can be made using the core
construction of this invention as shown in FIGS. 1 and 2 discussed
above. Such golf ball designs include, for example, three-piece,
four-piece, and five-piece designs. It should be understood that
the golf balls shown in FIGS. 1 and 2 are for illustrative purposes
only and are not meant to be restrictive. Other golf ball
constructions can be made in accordance with this invention.
Test Methods
[0145] Hardness.
[0146] The center hardness of a core is obtained according to the
following procedure. The core is gently pressed into a
hemispherical holder having an internal diameter approximately
slightly smaller than the diameter of the core, such that the core
is held in place in the hemispherical portion of the holder while
concurrently leaving the geometric central plane of the core
exposed. The core is secured in the holder by friction, such that
it will not move during the cutting and grinding steps, but the
friction is not so excessive that distortion of the natural shape
of the core would result. The core is secured such that the parting
line of the core is roughly parallel to the top of the holder. The
diameter of the core is measured 90 degrees to this orientation
prior to securing. A measurement is also made from the bottom of
the holder to the top of the core to provide a reference point for
future calculations. A rough cut is made slightly above the exposed
geometric center of the core using a band saw or other appropriate
cutting tool, making sure that the core does not move in the holder
during this step. The remainder of the core, still in the holder,
is secured to the base plate of a surface grinding machine. The
exposed `rough` surface is ground to a smooth, flat surface,
revealing the geometric center of the core, which can be verified
by measuring the height from the bottom of the holder to the
exposed surface of the core, making sure that exactly half of the
original height of the core, as measured above, has been removed to
within 0.004 inches. Leaving the core in the holder, the center of
the core is found with a center square and carefully marked and the
hardness is measured at the center mark according to ASTM D-2240.
Additional hardness measurements at any distance from the center of
the core can then be made by drawing a line radially outward from
the center mark, and measuring the hardness at any given distance
along the line, typically in 2 mm increments from the center. The
hardness at a particular distance from the center should be
measured along at least two, preferably four, radial arms located
180.degree. apart, or 90.degree. apart, respectively, and then
averaged. All hardness measurements performed on a plane passing
through the geometric center are performed while the core is still
in the holder and without having disturbed its orientation, such
that the test surface is constantly parallel to the bottom of the
holder, and thus also parallel to the properly aligned foot of the
durometer.
[0147] The outer surface hardness of a golf ball layer is measured
on the actual outer surface of the layer and 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, care must be taken to
ensure that the golf ball or golf ball subassembly is centered
under the durometer indenter before a surface hardness reading is
obtained. A calibrated, digital durometer, capable of reading to
0.1 hardness units is used for the 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.
[0148] In certain embodiments, a point or plurality of points
measured along the "positive" or "negative" gradients may be above
or below a line fit through the gradient and its outermost and
innermost hardness values. In an alternative preferred embodiment,
the hardest point along a particular steep "positive" or "negative"
gradient may be higher than the value at the innermost portion of
the inner core (the geometric center) or outer core layer (the
inner surface)--as long as the outermost point (i.e., the outer
surface of the inner core) is greater than (for "positive") or
lower than (for "negative") the innermost point (i.e., the
geometric center of the inner core or the inner surface of the
outer core layer), such that the "positive" and "negative"
gradients remain intact.
[0149] As discussed above, the direction of the hardness gradient
of a golf ball layer is defined by the difference in hardness
measurements taken at the outer and inner surfaces of a particular
layer. The center hardness of an inner core and hardness of the
outer surface of an inner core in a single-core ball or outer core
layer are readily determined according to the test procedures
provided above. The outer surface of the inner core layer (or other
optional intermediate core layers) in a dual-core ball are also
readily determined according to the procedures given herein for
measuring the outer surface hardness of a golf ball layer, if the
measurement is made prior to surrounding the layer with an
additional core layer. Once an additional core layer surrounds a
layer of interest, the hardness of the inner and outer surfaces of
any inner or intermediate layers can be difficult to determine.
Therefore, for purposes of the present invention, when the hardness
of the inner or outer surface of a core layer is needed after the
inner layer has been surrounded with another core layer, the test
procedure described above for measuring a point located 1 mm from
an interface is used.
[0150] Also, 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. Shore hardness (for example, Shore C or
Shore D hardness) was measured according to the test method ASTM
D-2240.
[0151] Compression.
[0152] As disclosed in Jeff Dalton's Compression by Any Other Name,
Science and Golf IV, Proceedings of the World Scientific Congress
of Golf (Eric Thain ed., Routledge, 2002) ("J. Dalton"), several
different methods can be used to measure compression, including
Atti compression, Riehle compression, load/deflection measurements
at a variety of fixed loads and offsets, and effective modulus. For
purposes of the present invention, "compression" refers to Atti
compression and 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. Very low
stiffness cores 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 42.7 mm (1.68 inches); thus, smaller objects, such as golf ball
cores, must be shimmed to a total height of 42.7 mm 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. Compression may be measured as described in
McNamara et al., U.S. Pat. No. 7,777,871, the disclosure of which
is hereby incorporated by reference.
[0153] Coefficient of Restitution ("COR").
[0154] The 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. The COR is then calculated as the ratio of the
ball's outgoing transit time period to the ball's incoming transit
time period (COR=V.sub.out/V.sub.in=T.sub.in/T.sub.out).
EXAMPLES
[0155] The examples below are for illustrative purposes only, to
set forth particularly suitable highly neutralized polymer
compositions for forming the inner core layer and/or outer core
layer. In no manner is the present invention limited to the
specific disclosures therein.
[0156] The following commercially available materials were used in
the below examples: [0157] A-C.RTM. 5120 ethylene acrylic acid
copolymer with an acrylic acid content of 15%, [0158] A-C.RTM. 5180
ethylene acrylic acid copolymer with an acrylic acid content of
20%, [0159] A-C.RTM. 395 high density oxidized polyethylene
homopolymer, and [0160] A-C.RTM. 575 ethylene maleic anhydride
copolymer, commercially available from Honeywell; [0161] CB23
high-cis neodymium-catalyzed polybutadiene rubber, commercially
available from Lanxess Corporation; [0162] CA1700 Soya fatty acid,
CA1726 linoleic acid, and CA1725 conjugated linoleic acid,
commercially available from Chemical Associates; [0163]
Century.RTM. 1107 highly purified isostearic acid mixture of
branched and straight-chain C18 fatty acid, commercially available
from Arizona Chemical; [0164] Clarix.RTM. 011370-01 ethylene
acrylic acid copolymer with an acrylic acid content of 13% and
[0165] Clarix.RTM. 011536-01 ethylene acrylic acid copolymer with
an acrylic acid content of 15%, commercially available from A.
Schulman Inc.; [0166] Elvaloy.RTM. AC 1224 ethylene-methyl acrylate
copolymer with a methyl acrylate content of 24 wt %, [0167]
Elvaloy.RTM. AC 1335 ethylene-methyl acrylate copolymer with a
methyl acrylate content of 35 wt %, [0168] Elvaloy.RTM. AC 2116
ethylene-ethyl acrylate copolymer with an ethyl acrylate content of
16 wt %, [0169] Elvaloy.RTM. AC 3427 ethylene-butyl acrylate
copolymer having a butyl acrylate content of 27 wt %, and [0170]
Elvaloy.RTM. AC 34035 ethylene-butyl acrylate copolymer having a
butyl acrylate content of 35 wt %, commercially available from E.
I. du Pont de Nemours and Company; [0171] Escor.RTM. AT-320
ethylene acid terpolymer, commercially available from ExxonMobil
Chemical Company; [0172] Exxelor.RTM. VA 1803 amorphous ethylene
copolymer functionalized with maleic anhydride, commercially
available from ExxonMobil Chemical Company; [0173] Fusabond.RTM.
N525 metallocene-catalyzed polyethylene, [0174] Fusabond.RTM. N416
chemically modified ethylene elastomer, [0175] Fusabond.RTM. C190
anhydride modified ethylene vinyl acetate copolymer, and [0176]
Fusabond.RTM. P614 functionalized polypropylene, commercially
available from E. I. du Pont de Nemours and Company; [0177]
Hytrel.RTM. 3078 very low modulus thermoplastic polyester
elastomer, commercially available from E. I. du Pont de Nemours and
Company; [0178] Kraton.RTM. FG 1901 GT linear triblock copolymer
based on styrene and ethylene/butylene with a polystyrene content
of 30% and [0179] Kraton.RTM. FG1924GT linear triblock copolymer
based on styrene and ethylene/butylene with a polystyrene content
of 13%, commercially available from Kraton Performance Polymers
Inc.; [0180] Lotader.RTM. 4603, 4700 and 4720, random copolymers of
ethylene, acrylic ester and maleic anhydride, commercially
available from Arkema Corporation; [0181] Nordel.RTM. IP 4770 high
molecular weight semi-crystalline EPDM rubber, commercially
available from The Dow Chemical Company; [0182] Nucrel.RTM. 9-1,
Nucrel.RTM. 599, Nucrel.RTM. 960, Nucrel.RTM. 0407, Nucrel.RTM.
0609, Nucrel.RTM. 1214, Nucrel.RTM. 2906, Nucrel.RTM. 2940,
Nucrel.RTM. 30707, Nucrel.RTM. 31001, and [0183] Nucrel.RTM. AE
acid copolymers, commercially available from E. I. du Pont de
[0184] Nemours and Company; [0185] Primacor.RTM. 3150, 3330, 59801,
and 59901 acid copolymers, commercially available from The Dow
Chemical Company; [0186] Royaltuf.RTM. 498 maleic anhydride
modified polyolefin based on an amorphous EPDM, commercially
available from Chemtura Corporation; [0187] Sylfat.RTM. FA2 tall
oil fatty acid, commercially available from Arizona Chemical;
[0188] Vamac.RTM. G terpolymer of ethylene, methylacrylate and a
cure site monomer, commercially available from E. I. du Pont de
Nemours and Company; and [0189] XUS 60758.08L ethylene acrylic acid
copolymer with an acrylic acid content of 13.5%, commercially
available from The Dow Chemical Company.
[0190] Various compositions were melt blended using components as
given in Table 3 below. The compositions were neutralized by adding
a cation source in an amount sufficient to neutralize,
theoretically, 110% of the acid groups present in components 1 and
3, except for example 72, in which the cation source was added in
an amount sufficient to neutralize 75% of the acid groups.
Magnesium hydroxide was used as the cation source, except for
example 68, in which magnesium hydroxide and sodium hydroxide were
used in an equivalent ratio of 4:1. In addition to components 1-3
and the cation source, example 71 contains ethyl oleate
plasticizer.
[0191] The relative amounts of component 1 and component 2 used are
indicated in Table 3 below, and are reported in wt %, based on the
combined weight of components 1 and 2. The relative amounts of
component 3 used are indicated in Table 3 below, and are reported
in wt %, based on the total weight of the composition
TABLE-US-00003 TABLE 3 Example Component 1 wt % Component 2 wt %
Component 3 wt % 1 Primacor 5980I 78 Lotader 4603 22 magnesium
oleate 41.6 2 Primacor 5980I 84 Elvaloy AC 1335 16 magnesium oleate
41.6 3 Primacor 5980I 78 Elvaloy AC 3427 22 magnesium oleate 41.6 4
Primacor 5980I 78 Elvaloy AC 1335 22 magnesium oleate 41.6 5
Primacor 5980I 78 Elvaloy AC 1224 22 magnesium oleate 41.6 6
Primacor 5980I 78 Lotader 4720 22 magnesium oleate 41.6 7 Primacor
5980I 85 Vamac G 15 magnesium oleate 41.6 8 Primacor 5980I 90 Vamac
G 10 magnesium oleate 41.6 8.1 Primacor 5990I 90 Fusabond 614 10
magnesium oleate 41.6 9 Primacor 5980I 78 Vamac G 22 magnesium
oleate 41.6 10 Primacor 5980I 75 Lotader 4720 25 magnesium oleate
41.6 11 Primacor 5980I 55 Elvaloy AC 3427 45 magnesium oleate 41.6
12 Primacor 5980I 55 Elvaloy AC 1335 45 magnesium oleate 41.6 12.1
Primacor 5980I 55 Elvaloy AC 34035 45 magnesium oleate 41.6 13
Primacor 5980I 55 Elvaloy AC 2116 45 magnesium oleate 41.6 14
Primacor 5980I 78 Elvaloy AC 34035 22 magnesium oleate 41.6 14.1
Primacor 5990I 80 Elvaloy AC 34035 20 magnesium oleate 41.6 15
Primacor 5980I 34 Elvaloy AC 34035 66 magnesium oleate 41.6 16
Primacor 5980I 58 Vamac G 42 magnesium oleate 41.6 17 Primacor
5990I 80 Fusabond 416 20 magnesium oleate 41.6 18 Primacor 5980I
100 -- -- magnesium oleate 41.6 19 Primacor 5980I 78 Fusabond 416
22 magnesium oleate 41.6 20 Primacor 5990I 100 -- -- magnesium
oleate 41.6 21 Primacor 5990I 20 Fusabond 416 80 magnesium oleate
41.6 21.1 Primacor 5990I 20 Fusabond 416 80 magnesium oleate 31.2
21.2 Primacor 5990I 20 Fusabond 416 80 magnesium oleate 20.8 22
Clarix 011370 30.7 Fusabond 416 69.3 magnesium oleate 41.6 23
Primacor 5990I 20 Royaltuf 498 80 magnesium oleate 41.6 24 Primacor
5990I 80 Royaltuf 498 20 magnesium oleate 41.6 25 Primacor 5990I 80
Kraton FG1924GT 20 magnesium oleate 41.6 26 Primacor 5990I 20
Kraton FG1924GT 80 magnesium oleate 41.6 27 Nucrel 30707 57
Fusabond 416 43 magnesium oleate 41.6 28 Primacor 5990I 80 Hytrel
3078 20 magnesium oleate 41.6 29 Primacor 5990I 20 Hytrel 3078 80
magnesium oleate 41.6 30 Primacor 5980I 26.8 Elvaloy AC 34035 73.2
magnesium oleate 41.6 31 Primacor 5980I 26.8 Lotader 4603 73.2
magnesium oleate 41.6 32 Primacor 5980I 26.8 Elvaloy AC 2116 73.2
magnesium oleate 41.6 33 Escor AT-320 30 Elvaloy AC 34035 52
magnesium oleate 41.6 Primacor 5980I 18 34 Nucrel 30707 78.5
Elvaloy AC 34035 21.5 magnesium oleate 41.6 35 Nucrel 30707 78.5
Fusabond 416 21.5 magnesium oleate 41.6 36 Primacor 5980I 26.8
Fusabond 416 73.2 magnesium oleate 41.6 37 Primacor 5980I 19.5
Fusabond N525 80.5 magnesium oleate 41.6 38 Clarix 011536-01 26.5
Fusabond N525 73.5 magnesium oleate 41.6 39 Clarix 011370-01 31
Fusabond N525 69 magnesium oleate 41.6 39.1 XUS 60758.08L 29.5
Fusabond N525 70.5 magnesium oleate 41.6 40 Nucrel 31001 42.5
Fusabond N525 57.5 magnesium oleate 41.6 41 Nucrel 30707 57.5
Fusabond N525 42.5 magnesium oleate 41.6 42 Escor AT-320 66.5
Fusabond N525 33.5 magnesium oleate 41.6 43 Nucrel 2906/2940 21
Fusabond N525 79 magnesium oleate 41.6 44 Nucrel 960 26.5 Fusabond
N525 73.5 magnesium oleate 41.6 45 Nucrel 1214 33 Fusabond N525 67
magnesium oleate 41.6 46 Nucrel 599 40 Fusabond N525 60 magnesium
oleate 41.6 47 Nucrel 9-1 44.5 Fusabond N525 55.5 magnesium oleate
41.6 48 Nucrel 0609 67 Fusabond N525 33 magnesium oleate 41.6 49
Nucrel 0407 100 -- -- magnesium oleate 41.6 50 Primacor 5980I 90
Fusabond N525 10 magnesium oleate 41.6 51 Primacor 5980I 80
Fusabond N525 20 magnesium oleate 41.6 52 Primacor 5980I 70
Fusabond N525 30 magnesium oleate 41.6 53 Primacor 5980I 60
Fusabond N525 40 magnesium oleate 41.6 54 Primacor 5980I 50
Fusabond N525 50 magnesium oleate 41.6 55 Primacor 5980I 40
Fusabond N525 60 magnesium oleate 41.6 56 Primacor 5980I 30
Fusabond N525 70 magnesium oleate 41.6 57 Primacor 5980I 20
Fusabond N525 80 magnesium oleate 41.6 58 Primacor 5980I 10
Fusabond N525 90 magnesium oleate 41.6 59 -- -- Fusabond N525 100
magnesium oleate 41.6 60 Nucrel 0609 40 Fusabond N525 20 magnesium
oleate 41.6 Nucrel 0407 40 61 Nucrel AE 100 -- -- magnesium oleate
41.6 62 Primacor 5980I 30 Fusabond N525 70 CA1700 soya fatty acid
41.6 magnesium salt 63 Primacor 5980I 30 Fusabond N525 70 CA1726
linoleic acid 41.6 magnesium salt 64 Primacor 5980I 30 Fusabond
N525 70 CA1725 41.6 conjugated linoleic acid magnesium salt 65
Primacor 5980I 30 Fusabond N525 70 Century 1107 41.6 isostearic
acid magnesium salt 66 A-C 5120 73.3 Lotader 4700 26.7 oleic acid
41.6 magnesium salt 67 A-C 5120 73.3 Elvaloy 34035 26.7 oleic acid
41.6 magnesium salt 68 Primacor 5980I 78.3 Lotader 4700 21.7 oleic
acid 41.6 magnesium salt and sodium salt 69 Primacor 5980I 47
Elvaloy AC34035 13 -- -- A-C 5180 40 70 Primacor 5980I 30 Fusabond
N525 70 Sylfat FA2 41.6 magnesium salt 71 Primacor 5980I 30
Fusabond N525 70 oleic acid 31.2 magnesium salt ethyl oleate 10 72
Primacor 5980I 80 Fusabond N525 20 sebacic acid 41.6 magnesium salt
73 Primacor 5980I 60 -- -- -- -- A-C 5180 40 74 Primacor 5980I 78.3
-- -- oleic acid 41.6 A-C 575 21.7 magnesium salt 75 Primacor 5980I
78.3 Exxelor VA 1803 21.7 oleic acid 41.6 magnesium salt 76
Primacor 5980I 78.3 A-C 395 21.7 oleic acid 41.6 magnesium salt 77
Primacor 5980I 78.3 Fusabond C190 21.7 oleic acid 41.6 magnesium
salt 78 Primacor 5980I 30 Kraton FG 1901 70 oleic acid 41.6
magnesium salt 79 Primacor 5980I 30 Royaltuf 498 70 oleic acid 41.6
magnesium salt 80 A-C 5120 40 Fusabond N525 60 oleic acid 41.6
magnesium salt 81 Primacor 5980I 30 Fusabond N525 70 erucic acid
41.6 magnesium salt 82 Primacor 5980I 30 CB23 70 oleic acid 41.6
magnesium salt 83 Primacor 5980I 30 Nordel IP 4770 70 oleic acid
41.6 magnesium salt 84 Primacor 5980I 48 Fusabond N525 20 oleic
acid 41.6 A-C 5180 32 magnesium salt 85 Nucrel 2806 22.2 Fusabond
N525 77.8 oleic acid 41.6 magnesium salt 86 Primacor 3330 61.5
Fusabond N525 38.5 oleic acid 41.6 magnesium salt 87 Primacor 3330
45.5 Fusabond N525 20 oleic acid 41.6 Primacor 3150 34.5 magnesium
salt 88 Primacor 3330 28.5 -- -- oleic acid 41.6 Primacor 3150 71.5
magnesium salt 89 Primacor 3150 67 Fusabond N525 33 oleic acid 41.6
magnesium salt 90 Primacor 5980I 55 Elvaloy AC 34035 45 oleic acid
31.2 magnesium salt ethyl oleate 10
[0192] Solid spheres of each composition were injection molded, and
the solid sphere COR, compression, Shore D hardness, and Shore C
hardness of the resulting spheres were measured after two weeks.
The results are reported in Table 4 below. The surface hardness of
a sphere 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 sphere 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,
care must be taken to insure that the sphere 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 and is set to record
the maximum hardness reading obtained for each measurement. 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 conform to ASTM D-2240.
TABLE-US-00004 TABLE 4 Solid Sphere Solid Sphere Solid Sphere Solid
Sphere Ex. COR Compression Shore D Shore C 1 0.845 120 59.6 89.2 2
* * * * 3 0.871 117 57.7 88.6 4 0.867 122 63.7 90.6 5 0.866 119
62.8 89.9 6 * * * * 7 * * * * 8 * * * * 8.1 0.869 127 65.3 92.9 9 *
* * * 10 * * * * 11 * * * * 12 0.856 101 55.7 82.4 12.1 0.857 105
53.2 81.3 13 * * * * 14 0.873 122 64.0 91.1 14.1 * * * * 15 * * * *
16 * * * * 17 0.878 117 60.1 89.4 18 0.853 135 67.6 94.9 19 * * * *
20 0.857 131 66.2 94.4 21 0.752 26 34.8 57.1 21.1 0.729 9 34.3 56.3
21.2 0.720 2 33.8 55.2 22 * * * * 23 * * * * 24 * * * * 25 * * * *
26 * * * * 27 * * * * 28 * * * * 29 * * * * 30 ** 66 42.7 65.5 31
0.730 67 45.6 68.8 32 ** 100 52.4 78.2 33 0.760 64 43.6 64.5 34
0.814 91 52.8 80.4 35 * * * * 36 * * * * 37 * * * * 38 * * * * 39 *
* * * 39.1 * * * * 40 * * * * 41 * * * * 42 * * * * 43 * * * * 44 *
* * * 45 * * * * 46 * * * * 47 * * * * 48 * * * * 49 * * * * 50 * *
* * 51 0.873 121 61.5 90.2 52 0.870 116 60.4 88.2 53 0.865 107 57.7
84.4 54 0.853 97 53.9 80.2 55 0.837 82 50.1 75.5 56 0.818 66 45.6
70.7 57 0.787 45 41.3 64.7 58 0.768 26 35.9 57.3 59 * * * * 60 * *
* * 61 * * * * 62 * * * * 63 * * * * 64 * * * * 65 * * * * 66 * * *
* 67 * * * * 68 * * * * 69 * * * * 70 * * * * 71 * * * * 72 * * * *
73 * * * * 74 * * * * 75 * * * * 76 * * * * 77 * * * * 78 * * * *
79 * * * * 80 * * * * 81 * * * * 82 * * * * 83 * * * * 84 * * * *
85 * * * * 86 * * * * 87 * * * * 88 * * * * 89 * * * * 90 * * * * *
not measured ** sphere broke during measurement
[0193] When numerical lower limits and numerical upper limits are
set forth herein, it is contemplated that any combination of these
values may be used.
[0194] All patents, publications, test procedures, and other
references cited herein, including priority documents, are fully
incorporated by reference to the extent such disclosure is not
inconsistent with this invention and for all jurisdictions in which
such incorporation is permitted.
[0195] While the illustrative embodiments of the invention have
been described with particularity, it will be understood that
various other modifications will be apparent to and can be readily
made by those of ordinary skill in the art without departing from
the spirit and scope of the invention. Accordingly, it is not
intended that the scope of the claims appended hereto be limited to
the examples and descriptions set forth herein, but rather that the
claims be construed as encompassing all of the features of
patentable novelty which reside in the present invention, including
all features which would be treated as equivalents thereof by those
of ordinary skill in the art to which the invention pertains.
* * * * *