U.S. patent application number 11/370733 was filed with the patent office on 2007-09-13 for rubber compositions comprising benzoquinones and the use thereof in golf balls.
Invention is credited to David A. Bulpett, Brian Comeau, Douglas S. Goguen.
Application Number | 20070213442 11/370733 |
Document ID | / |
Family ID | 38479783 |
Filed Date | 2007-09-13 |
United States Patent
Application |
20070213442 |
Kind Code |
A1 |
Bulpett; David A. ; et
al. |
September 13, 2007 |
Rubber compositions comprising benzoquinones and the use thereof in
golf balls
Abstract
The present invention is directed to a golf ball having at least
one layer formed from a rubber composition comprising a base
rubber, at least 0.05 parts by weight of a free radical initiator,
per 100 parts of the base rubber, and at least 0.1 parts by weight
of a benzoquinone, per 100 parts of the base rubber. The rubber
composition may be present in any one or more of a core layer, a
cover layer, or an intermediate layer.
Inventors: |
Bulpett; David A.; (Boston,
MA) ; Comeau; Brian; (Berkley, MA) ; Goguen;
Douglas S.; (New Bedford, MA) |
Correspondence
Address: |
ACUSHNET COMPANY
333 BRIDGE STREET
P. O. BOX 965
FAIRHAVEN
MA
02719
US
|
Family ID: |
38479783 |
Appl. No.: |
11/370733 |
Filed: |
March 7, 2006 |
Current U.S.
Class: |
524/358 ;
473/367 |
Current CPC
Class: |
C08K 5/14 20130101; C08K
5/098 20130101; A63B 37/0065 20130101; C08K 5/08 20130101; C08K
5/098 20130101; A63B 37/0003 20130101; A63B 37/0061 20130101; C08K
5/14 20130101; C08K 5/08 20130101; A63B 37/0038 20130101; A63B
37/005 20130101; C08L 21/00 20130101; C08L 21/00 20130101; C08L
21/00 20130101 |
Class at
Publication: |
524/358 ;
473/367 |
International
Class: |
C08L 21/00 20060101
C08L021/00; A63B 37/06 20060101 A63B037/06 |
Claims
1. A golf ball comprising a core and a cover, wherein the core has
at least one layer formed from a rubber composition comprising: (a)
a base rubber; (b) at least 0.05 parts by weight of a free radical
initiator per 100 parts of the base rubber; and (c) at least 0.15
parts by weight of a benzoquinone per 100 parts of the base
rubber.
2. The golf ball of claim 1, wherein a ratio (P.sub.BQ/P.sub.FRI)
of the amount of the benzoquinone present in the rubber composition
(P.sub.BQ), measured in parts by weight per 100 parts of the base
rubber, to the amount of free radical initiator present in the
rubber composition (P.sub.FRI), measured in parts by weight per 100
parts of the base rubber, is from 0.05 to 2.
3. The golf ball of claim 2, wherein P.sub.BQ/P.sub.FRI is from
0.25 to 2.
4. The golf ball of claim 2, wherein P.sub.BQ/P.sub.FRI is at least
0.05 and less than 0.5.
5. The golf ball of claim 2, wherein P.sub.BQ/P.sub.FRI is at least
0.25 and less than 0.5.
6. The golf ball of claim 2, wherein P.sub.BQ/P.sub.FRI is from
0.25 to 0.45.
7. The golf ball of claim 1, wherein the benzoquinone is selected
from compounds represented by the following formula, and hydrates
thereof: ##STR5## wherein each R.sub.1, R.sub.2, R.sub.3, and
R.sub.4 is independently selected from the group consisting of
hydrogen, a halogen group (F, Cl, Br, I), an alkyl group, a
carboxyl group (--COOH) and metal salts thereof (e.g.,
--COO.sup.-M.sup.+) and esters thereof (--COOR), an acetate group
(--CH.sub.2COOH) and esters thereof (--CH.sub.2COOR), a formyl
group (--CHO), an acyl group (--COR), an acetyl group
(--COCH.sub.3), a halogenated carbonyl group (--COX), a sulfo group
(--SO.sub.3H) and esters thereof (--SO.sub.3R), a halogenated
sulfonyl group (--SO.sub.2X), a sulfino group (--SO.sub.2H), an
alkylsulfinyl group (--SOR), a carbamoyl group (--CONH.sub.2), a
halogenated alkyl group, a cyano group (--CN), an alkoxy group
(--OR), a hydroxy group (--OH) and metal salts thereof (e.g.,
--O.sup.-M.sup.+), an amino group (--NH.sub.2), a nitro group
(--NO.sub.2), an aryl group (e.g., phenyl, tolyl, etc.), an aryloxy
group (e.g., phenoxy, etc.), an arylalkyl group [e.g., cumyl
(--C(CH.sub.3).sub.2phenyl); benzyl (--CH.sub.2 phenyl)], a nitroso
group (--NO), an acetamido group (--NHCOCH.sub.3), and a vinyl
group (--CH.dbd.CH.sub.2).
8. The golf ball of claim 1, wherein the benzoquinone is selected
from methyl p-benzoquinone and tetrachloro p-benzoquinone.
9. The golf ball of claim 1, wherein the rubber composition
comprises one or more coagents selected from metal salts of
acrylates, diacrylates, methacrylates, and dimethacrylates, wherein
the metal is selected from magnesium, calcium, zinc, aluminum,
lithium, and nickel; and wherein the total amount of metal salts of
acrylates, diacrylates, methacrylates, and dimethacrylates present
in the rubber composition is less than 20 parts per 100 parts of
the base rubber.
10. The golf ball of claim 1, wherein the rubber composition is
substantially free of organosulfur compounds.
11. The golf ball of claim 1, wherein the amount of the
benzoquinone present in the rubber composition is at least 0.2
parts by weight per 100 parts of the base rubber.
12. The golf ball of claim 1, wherein the core is a single
layer.
13. The golf ball of claim 1, wherein the core comprises an inner
core layer and an outer core layer, and wherein the inner core
layer is formed from the rubber composition.
14. The golf ball of claim 1, wherein the core comprises an inner
core layer and an outer core layer, and wherein the outer core
layer is formed from the rubber composition
15. A golf ball comprising a core and a cover, wherein the core has
at least one layer formed from a rubber composition comprising: (a)
a base rubber; (b) at least 0.05 parts by weight of a free radical
initiator per 100 parts of the base rubber; and (c) at least 0.1
parts by weight of a benzoquinone per 100 parts of the base rubber,
wherein the benzoquinone is selected from compounds represented by
the following formula, and hydrates thereof: ##STR6## wherein each
R.sub.1, R.sub.2, R.sub.3, and R.sub.4 is independently selected
from the group consisting of: a metal salt of a carboxyl group
(e.g., --COO.sup.-M.sup.+), an acetate group (--CH.sub.2COOH) and
esters thereof (--CH.sub.2COOR), a hydroxy group (--OH), a metal
salt of a hydroxy group (e.g., --O.sup.-M.sup.+), an amino group
(--NH.sub.2), a nitro group (--NO.sub.2), an aryl group (e.g.,
phenyl, tolyl, etc.), an aryloxy group (e.g., phenoxy, etc.), an
arylalkyl group [e.g., cumyl (--C(CH.sub.3).sub.2phenyl); benzyl
(--CH.sub.2 phenyl)], a nitroso group (--NO), an acetamido group
(--NHCOCH.sub.3), and a vinyl group (--CH.dbd.CH.sub.2).
16. The golf ball of claim 15, wherein the rubber composition
comprises at least 0.2 parts by weight of the benzoquinone per 100
parts of the base rubber.
17. The golf ball of claim 15, wherein a ratio (P.sub.BQ/P.sub.FRI)
of the amount of the benzoquinone present in the rubber composition
(P.sub.BQ), measured in parts by weight per 100 parts of the base
rubber, to the amount of free radical initiator present in the
rubber composition (P.sub.FRI), measured in parts by weight per 100
parts of the base rubber, is at least 0.05.
18. The golf ball of claim 15, wherein the rubber composition is
substantially free of organosulfur compounds.
19. A golf ball comprising a core and a cover, wherein the core has
at least one layer formed from a rubber composition comprising: (a)
a base rubber; (b) at least 0.05 parts by weight of a free radical
initiator, per 100 parts of the base rubber; and (c) at least 0.15
parts by weight of a benzoquinone, per 100 parts of the base
rubber; wherein the benzoquinone is selected from compounds
represented by the following formula, and hydrates thereof:
##STR7## wherein each R.sub.1, R.sub.2, R.sub.3, and R.sub.4 is
independently selected from the group consisting of hydrogen, a
halogen group (F, Cl, Br, I), an alkyl group, a carboxyl group
(--COOH) and metal salts thereof (e.g., --COO.sup.-M.sup.+) and
esters thereof (--COOR), an acetate group (--CH.sub.2COOH) and
esters thereof (--CH.sub.2COOR), a formyl group (--CHO), an acyl
group (--COR), an acetyl group (--COCH.sub.3), a halogenated
carbonyl group (--COX), a sulfo group (--SO.sub.3H) and esters
thereof (--SO.sub.3R), a halogenated sulfonyl group (--SO.sub.2X),
a sulfino group (--SO.sub.2H), an alkylsulfinyl group (--SOR), a
carbamoyl group (--CONH.sub.2), a halogenated alkyl group, a cyano
group (--CN), an alkoxy group (--OR), a hydroxy group (--OH) and
metal salts thereof (e.g., --O.sup.-M.sup.+), an amino group
(--NH.sub.2), a nitro group (--NO.sub.2), an aryl group (e.g.,
phenyl, tolyl, etc.), an aryloxy group (e.g., phenoxy, etc.), an
arylalkyl group [e.g., cumyl (--C(CH.sub.3).sub.2phenyl); benzyl
(--CH.sub.2 phenyl)], a nitroso group (--NO), an acetamido group
(--NHCOCH.sub.3), and a vinyl group (--CH.dbd.CH.sub.2); wherein a
ratio (P.sub.BQ/P.sub.FRI) of the amount of the benzoquinone
present in the rubber composition (P.sub.BQ), measured in parts by
weight per 100 parts of the base rubber, to the amount of free
radical initiator present in the rubber composition (P.sub.FRI),
measured in parts by weight per 100 parts of the base rubber, is
from 0.25 to 2; and wherein the rubber composition is substantially
free of organosulfur compounds.
20. The golf ball of claim 19, wherein P.sub.BQ/P.sub.FRI is at
least 0.25 and less than 0.5.
Description
FIELD OF THE INVENTION
[0001] The present invention is directed to rubber compositions
comprising a base rubber, at least 0.05 parts by weight of a free
radical initiator, per 100 parts of the base rubber, and at least
0.10 parts by weight of a benzoquinone, per 100 parts of the base
rubber. The present invention is also directed to the use of such
compositions in golf equipment.
BACKGROUND OF THE INVENTION
Benzoquinones
[0002] The use of benzoquinones in rubber-based golf ball
compositions is known. For example, U.S. Pat. No. 6,339,119 to Ladd
et al. discloses a golf ball containing a cover layer and a core
layer, where the core layer is molded from a scorch retarding
composition comprising a scorch retarding peroxide, an elastomeric
polymer, and a crosslinking agent. The scorch retarding peroxide
typically contains a free radical scavenger selected from the group
consisting of benzoquinones, hydroquinones, phenols, benzaldehydes,
cyclohexadiene-1-ones, and mixtures thereof. The amount of the free
radical scavenger in the scorch retarding peroxide is preferably
from about 0.01 parts to about 2 parts per 100 parts of the
peroxide by weight.
[0003] U.S. Pat. No. 6,767,940 to Voorheis et al. is directed to a
golf ball having a core and cover, particularly to a golf ball core
formed from a composition including an elastomeric polymer, a free
radical initiator, and at least one stable free radical. The
composition can further include one or more free radical scavengers
and scorch retarders to increase the scorch time of the elastomeric
polymer. Suitable free radical scavengers include benzoquinones;
hydroquinones; phenols; benzaldehydes; cyclohexadiene-1-ones; and
mixtures thereof.
[0004] Additional background references include U.S. Pat. No.
6,919,393 to Mano et al., U.S. Pat. No. 6,956,128 to Higuchi et
al., U.S. Patent Application Publication No. 2002/0052253 to
Fushihara et al., and U.S. Pat. No. 6,488,597 to Iwami et al.
Resilient Cores
[0005] The primary source of resilience, as measured by coefficient
of restitution ("COR"), in commercially available golf balls is
polybutadiene rubber, which is generally used to form all or part
of the core. It is known that the resilience of a golf ball core,
at a given compression, may be increased by forming a core layer
from a rubber composition comprising an organosulfur compound.
However, organosulfur compounds can be expensive and can cause
processing difficulties.
[0006] Thus, a desire remains in the golf ball industry for novel
rubber compositions having high resilience at a given compression.
The present invention provides such compositions and their use in a
variety of golf ball core, cover, and intermediate layers.
SUMMARY OF THE INVENTION
[0007] In one embodiment, the present invention is directed to a
golf ball comprising a core and a cover, the core having at least
one layer formed from a rubber composition comprising a base
rubber, a free radical initiator, and a benzoquinone. The free
radical initiator is present in the rubber composition in an amount
of at least 0.05 parts by weight per 100 parts of the base rubber,
and the benzoquinone is present in the rubber composition in an
amount of at least 0.15 parts by weight per 100 parts of the base
rubber.
[0008] In another embodiment, the present invention is directed to
a golf ball comprising a core and a cover, the core having at least
one layer formed from a rubber composition comprising a baser
rubber, a free radical initiator, and a benzoquinone. The free
radical initiator is present in the rubber composition in an amount
of at least 0.05 parts by weight per 100 parts of the base rubber
and the benzoquinone is present in the rubber composition in an
amount of at least 0.1 parts by weight per 100 parts of the base
rubber. The benzoquinone is selected from compounds represented by
the following formula, and hydrates thereof: ##STR1##
[0009] wherein each R.sub.1, R.sub.2, R.sub.3, and R.sub.4 is
independently selected from the group consisting of: a metal salt
of a carboxyl group (e.g., --COO.sup.-M.sup.+), an acetate group
(--CH.sub.2COOH) and esters thereof (--CH.sub.2COOR), a hydroxy
group (--OH), a metal salt of a hydroxy group (e.g.,
--O.sup.-M.sup.+), an amino group (--NH.sub.2), a nitro group
(--NO.sub.2), an aryl group (e.g., phenyl, tolyl, etc.), an aryloxy
group (e.g., phenoxy, etc.), an arylalkyl group [e.g., cumyl
(--C(CH.sub.3).sub.2phenyl); benzyl (--CH.sub.2 phenyl)], a nitroso
group (--NO), an acetamido group (--NHCOCH.sub.3), and a vinyl
group (--CH.dbd.CH.sub.2).
[0010] In another embodiment, the present invention is directed to
a golf ball comprising a core and a cover, the core having at least
one layer formed from a rubber composition comprising a base
rubber, a free radical initiator, a benzoquinone, and substantially
free of organosulfur compounds. The free radical initiator is
present in the rubber composition in an amount of at least 0.05
parts by weight per 100 parts of the base rubber, the benzoquinone
is present in the rubber composition in an amount of at least 0.15
parts by weight per 100 parts of the base rubber, and a ratio of
the amount of the benzoquinone present in the rubber composition to
the amount of free radical initiator present in the rubber
composition is from 0.25 to 2. The benzoquinone is selected from
compounds represented by the following formula, and hydrates
thereof: ##STR2##
[0011] wherein each R.sub.1, R.sub.2, R.sub.3, and R.sub.4 is
independently selected from the group consisting of hydrogen, a
halogen group (F, Cl, Br, I), an alkyl group, a carboxyl group
(--COOH) and metal salts thereof (e.g., --COO.sup.-M.sup.+) and
esters thereof (--COOR), an acetate group (--CH.sub.2COOH) and
esters thereof (--CH.sub.2COOR), a formyl group (--CHO), an acyl
group (--COR), an acetyl group (--COCH.sub.3), a halogenated
carbonyl group (--COX), a sulfo group (--SO.sub.3H) and esters
thereof (--SO.sub.3R), a halogenated sulfonyl group (--SO.sub.2X),
a sulfino group (--SO.sub.2H), an alkylsulfinyl group (--SOR), a
carbamoyl group (--CONH.sub.2), a halogenated alkyl group, a cyano
group (--CN), an alkoxy group (--OR), a hydroxy group (--OH) and
metal salts thereof (e.g., --O.sup.-M.sup.+), an amino group
(--NH.sub.2), a nitro group (--NO.sub.2), an aryl group (e.g.,
phenyl, tolyl, etc.), an aryloxy group (e.g., phenoxy, etc.), an
arylalkyl group [e.g., cumyl (--C(CH.sub.3).sub.2phenyl); benzyl
(--CH.sub.2 phenyl)], a nitroso group (--NO), an acetamido group
(--NHCOCH.sub.3), and a vinyl group (--CH.dbd.CH.sub.2).
DETAILED DESCRIPTION OF THE INVENTION
[0012] Golf balls of the present invention include one-piece,
two-piece (i.e., solid core and a cover), multi-layer (i.e., solid
core of one or more layers and/or a cover of one or more layers),
and wound golf balls having a variety of core structures,
intermediate layers, covers, and coatings. Golf ball cores may
consist of a single, unitary layer, comprising the entire core from
the center of the core to its outer periphery, or they may consist
of a center surrounded by at least one outer core layer. The
center, innermost portion of the core is preferably solid, but may
be hollow or liquid-, gel-, or gas-filled. The outer core layer may
be solid, or it may be a wound layer formed of a tensioned
elastomeric material. Golf ball covers may also contain one or more
layers, such as a double cover having an inner and outer cover
layer. Optionally, additional layers may be disposed between the
core and cover.
[0013] Golf balls of the present invention have at least one layer
which is formed from a rubber composition of the present invention.
In a particular embodiment, the rubber composition of the present
invention is present in at least one core layer of a two-piece or
multi-layer golf ball.
Rubber Composition
[0014] Rubber compositions of the present invention comprise a base
rubber, at least one free radical initiator, and at least one free
radical scavenger.
[0015] The base rubber is selected from natural and synthetic
rubbers and mixtures thereof, including, but not limited to,
polybutadiene; mixtures of two or more polybutadienes;
styrene-butadiene; mixtures of two or more polybutadienes and
styrene-butadiene; and mixtures of polybutadiene(s) with one or
more additional rubbers selected from natural rubber, polyisoprene
rubber, ethylene propylene rubber, ethylene propylene diene 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), butyl rubber, halobutyl rubber,
polystyrene elastomers, polyethylene elastomers, polyurethane
elastomers, polyurea elastomers, metallocene-catalyzed elastomers,
and plastomers. When the base rubber is a mixture of polybutadiene
and at least one additional rubber, the amount of polybutadiene in
the mixture is preferably at least 40 wt %, based on the total
weight of the mixture. In a particular embodiment, the base rubber
is polybutadiene. Suitable examples of commercially available
polybutadienes include, but are not limited to, Buna CB 23,
commercially available from LANXESS Corporation; SE BR-1220,
commercially available from The Dow Chemical Company; Europrenes
NEOCIS.RTM. BR 40 and BR 60, commercially available from Polimeri
Europa; UBEPOL-BR.RTM. rubbers, commercially available from UBE
Industries, Ltd.; and BR 01 commercially available from Japan
Synthetic Rubber Co., Ltd.
[0016] The free radical initiator is selected from organic
peroxides, high energy radiation sources capable of generating free
radicals, and combinations thereof. 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 base
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 by weight
per 100 parts of the base rubber, 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 base rubber.
[0017] Coagents are commonly used with peroxides to increase the
state of cure. Suitable coagents 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 coagent is selected from zinc salts of acrylates,
diacrylates, methacrylates, and dimethacrylates. In another
particular embodiment, the coagent is zinc diacrylate. When the
coagent is zinc diacrylate and/or zinc dimethacrylate, the coagent
is typically included in the rubber composition in an amount within
the range having a lower limit of 1 part or 5 parts or 10 parts by
weight per 100 parts of the base rubber, and an upper limit of 19
parts or 20 parts or 25 parts or 30 parts or 35 parts or 40 parts
or 45 parts or 50 parts or 60 parts by weight per 100 parts of the
base rubber. When one or more less active coagents are used, such
as zinc monomethacrylate and various liquid acrylates and
methacrylates, the amount of less active coagent used may be the
same as or higher than for zinc diacrylate and zinc dimethacrylate
coagents.
[0018] Curing agents may also be used in compositions of the
present invention. Curing agents include, but are not limited to,
sulfur; N-oxydiethylene 2-benzothiazole sulfenamide;
N,N-di-ortho-tolylguanidine; bismuth dimethyldithiocarbamate;
N-cyclohexyl 2-benzothiazole sulfenamide; N,N-diphenylguanidine;
4-morpholinyl-2-benzothiazole disulfide; dipentamethylenethiuram
hexasulfide; thiuram disulfides; mercaptobenzothiazoles;
sulfenamides; dithiocarbamates; thiuram sulfides; guanidines;
thioureas; xanthates; dithiophosphates; aldehyde-amines;
dibenzothiazyl disulfide; tetraethylthiuram disulfide;
tetrabutylthiuram disulfide; and combinations thereof.
[0019] High energy radiation sources capable of generating free
radicals include, but are not limited to, electron beams,
ultra-violet radiation, gamma radiation, X-ray radiation, infrared
radiation, heat, and combinations thereof.
[0020] Further examples of suitable free radical initiators,
coagents, and curing agents are disclosed in U.S. Patent
Application Publication Nos. 2004/0214661 and 2003/0144087 and U.S.
Pat. Nos. 6,566,483, 6,695,718, and 6,939,907, the entire
disclosures of which are hereby incorporated herein by
reference.
[0021] Rubber compositions of the present invention comprise at
least one free radical scavenger. In a preferred embodiment, the
free radical scavenger is a benzoquinone compound. In a
particularly preferred embodiment, the free radical scavenger is a
benzoquinone compound selected from one or more compounds
represented by the following formula, and hydrates thereof:
##STR3##
[0022] wherein each R.sub.1, R.sub.2, R.sub.3, and R.sub.4 is
independently selected from the group consisting of hydrogen, a
halogen group (F, Cl, Br, I), an alkyl group, a carboxyl group
(--COOH) and metal salts thereof (e.g., --COO.sup.-M.sup.+) and
esters thereof (--COOR), an acetate group (--CH.sub.2COOH) and
esters thereof (--CH.sub.2COOR), a formyl group (--CHO), an acyl
group (--COR), an acetyl group (--COCH.sub.3), a halogenated
carbonyl group (--COX), a sulfo group (--SO.sub.3H) and esters
thereof (--SO.sub.3R), a halogenated sulfonyl group (--SO.sub.2X),
a sulfino group (--SO.sub.2H), an alkylsulfinyl group (--SOR), a
carbamoyl group (--CONH.sub.2), a halogenated alkyl group, a cyano
group (--CN), an alkoxy group (--OR), a hydroxy group (--OH) and
metal salts thereof (e.g., --O.sup.-M.sup.+), an amino group
(--NH.sub.2), a nitro group (--NO.sub.2), an aryl group (e.g.,
phenyl, tolyl, etc.), an aryloxy group (e.g., phenoxy, etc.), an
arylalkyl group [e.g., cumyl (--C(CH.sub.3).sub.2phenyl); benzyl
(--CH.sub.2 phenyl)], a nitroso group (--NO), an acetamido group
(--NHCOCH.sub.3), and a vinyl group (--CH.dbd.CH.sub.2).
[0023] In another particularly preferred embodiment, the free
radical scavenger is a benzoquinone compound selected from one or
more compounds represented by the following formula, and hydrates
thereof: ##STR4##
[0024] wherein each R.sub.1, R.sub.2, R.sub.3, and R.sub.4 is
independently selected from the group consisting of: a metal salt
of a carboxyl group (e.g., --COO.sup.-M.sup.+), an acetate group
(--CH.sub.2COOH) and esters thereof (--CH.sub.2COOR), a hydroxy
group (--OH), a metal salt of a hydroxy group (e.g.,
--O.sup.-M.sup.+), an amino group (--NH.sub.2), a nitro group
(--NO.sub.2), an aryl group (e.g., phenyl, tolyl, etc.), an aryloxy
group (e.g., phenoxy, etc.), an arylalkyl group [e.g., cumyl
(--C(CH.sub.3).sub.2phenyl); benzyl (--CH.sub.2 phenyl)], a nitroso
group (--NO), an acetamido group (--NHCOCH.sub.3), and a vinyl
group (--CH.dbd.CH.sub.2).
[0025] In another particularly preferred embodiment, the free
radical scavenger is a benzoquinone selected from methyl
p-benzoquinone and tetrachloro p-benzoquinone.
[0026] The free radical scavenger may be a combination of two or
more benzoquinones, each of which is independently selected from
compounds represented by one of the above formulas. The free
radical scavenger may also be a combination of one or more
benzoquinones and one or more non-benzoquinone free radical
scavengers, including, but not limited to, hydroquinones,
quinhydrones, catechols, and resorcinols.
[0027] The free radical scavenger is typically used in the form of
a liquid or solid. In a particular embodiment, the free radical
scavenger is used in a solid form and may be synthesized or
processed so as to have a particle size of 0.25 mm or less, or
0.125 mm or less, or 0.09 mm or less. In another particular
embodiment, the free radical scavenger is used in a solid form and
melts at 150.degree. F. or less, or 120.degree. F. or less, or at a
temperature that is the same as or less than the mixing temperature
of the base rubber.
[0028] The free radical scavenger is present in the rubber
composition in an amount of at least 0.1 parts by weight or at
least 0.15 parts by weight or at least 0.2 parts by weight per 100
parts of the base rubber, or an amount within the range having a
lower limit of 0.1 parts or 0.15 parts or 0.25 parts or 0.3 parts
or 0.375 parts by weight per 100 parts of the base rubber, and an
upper limit of 0.5 parts or 1 part or 1.5 parts or 2 parts or 3
parts by weight per 100 parts of the base rubber.
[0029] In a particular embodiment, a ratio (P.sub.BQ/P.sub.FRI) of
the amount (P.sub.BQ) of the benzoquinone present in the rubber
composition, measured in parts by weight per 100 parts of the base
rubber, to the amount (P.sub.FRI) of free radical initiator present
in the rubber composition, measured in parts by weight per 100
parts of the base rubber, is from 0.05 to 2. In another embodiment,
P.sub.BQ/P.sub.FRI is at least 0.05 and less than 0.5. In another
embodiment, P.sub.BQ/P.sub.FRI is at least 0.2 and less than 0.5.
In another embodiment, P.sub.BQ/P.sub.FRI is at least 0.25 and less
than 0.5. In yet another embodiment, P.sub.BQ/P.sub.FRI is within
the range having a lower limit of 0.05 or 0.2 or 0.25 and an upper
limit of 0.4 or 0.45 or 0.5 or 2.
[0030] Rubber compositions of the present invention optionally
contain one or more antioxidants. Some antioxidants also act as
free radical scavengers. Thus, when antioxidants are included in
the rubber composition, the amount of free radical initiator used
may be as high or higher than the amounts disclosed herein.
[0031] Rubber compositions of the present invention optionally
contain one or more particulate fillers selected from inorganic
fillers, such as zinc oxide, titanium dioxide, tin oxide, calcium
oxide, magnesium oxide, barium sulfate, zinc sulfate, calcium
carbonate, zinc carbonate, barium carbonate, mica, talc, clay,
silica, lead silicate, and the like; high specific gravity metal
powder fillers, such as tungsten powder, molybdenum powder, and the
like; regrind, i.e., core material that is ground and recycled; and
nano-fillers. The amount of particulate material(s) present in
rubber compositions of the present invention is typically within
the range having a lower limit of 5 parts or 10 parts by weight per
100 parts of the base rubber, and an upper limit of 30 parts or 50
parts or 100 parts by weight per 100 parts of the base rubber.
[0032] Rubber compositions of the present invention optionally
contain one or more additives selected from processing aids,
processing oils, plasticizers, coloring agents, fluorescent agents,
chemical blowing and foaming agents, defoaming agents, stabilizers,
softening agents, impact modifiers, and the like. The amount of
additive(s) typically present in rubber compositions of the present
invention is typically within the range having a lower limit of 0
parts by weight per 100 parts of the base rubber and an upper limit
of 20 parts or 50 parts or 100 parts or 150 parts by weight per 100
parts of the base rubber.
[0033] Filler materials may be dual-functional fillers, for
example, zinc oxide (which may be used as a filler/acid scavenger)
and titanium dioxide (which may be used as a filler/brightener
material). Further examples of suitable fillers and additives
include, but are not limited to, those disclosed in U.S. Patent
Application Publication No. 2003/0225197, the entire disclosure of
which is hereby incorporated herein by reference.
[0034] Rubber compositions of the present invention may have one or
more of the following properties relative to previously known golf
ball compositions: higher resilience, lower compression, increased
resilience at equal compression, decreased compression at equal
resilience, reduced crystallinity, increase in glass transition
temperature, and an "S-shaped" shift in the rheometer curve.
[0035] In some embodiments, rubber compositions of the present
invention have a combination of compression and COR values, as
measured on golf ball cores formed from the rubber composition,
previously achieved by adding organosulfur compounds to rubber
compositions. In some embodiments, rubber compositions of the
present invention have a combination of compression and COR values,
as measured on golf ball cores formed from the rubber composition,
superior to previously known compositions. Thus, rubber
compositions of the present invention may contain one or more
organosulfur compounds, but can have desirable compression and COR
properties without them. Suitable organosulfur compounds are more
fully disclosed, for example, in U.S. Pat. Nos. 6,635,716 and
6,919,393, the entire disclosures of which are hereby incorporated
herein by reference. In a particular embodiment, the rubber
composition is substantially free of organosulfur compounds.
"Substantially free," as used herein, means that the rubber
composition does not contain an organosulfur compound, or includes
one or more organosulfur compounds in an amount of less than 0.01
parts by weight per 100 parts of the base rubber.
[0036] The present invention is not limited by any particular
method for making the rubber composition.
[0037] Rubber compositions of the present invention can be used in
a variety of applications. For example, rubber compositions of the
present invention are suitable for use in golf equipment,
including, but not limited to, golf balls, golf shoes, and golf
clubs.
Golf Ball Applications
[0038] Golf balls of the present invention include one-piece,
two-piece, multi-layer, and wound golf balls, having at least one
layer which is formed from a rubber composition of the present
invention. In golf balls having two or more layers which comprise a
rubber composition of the present invention, the rubber composition
of one layer may be the same or a different rubber composition as
another layer. The layer(s) formed from the rubber composition of
the present invention can be any one or more of a core layer, a
cover layer, or an intermediate layer disposed between a core and a
cover.
[0039] Golf ball cores of the present invention include single,
dual, and multilayer cores, and preferably have an overall diameter
within the range having a lower limit of 0.75 inches or 1 inch or
1.25 inches or 1.4 inches and an upper limit of 1.55 inches or 1.6
inches or 1.62 inches or 1.63 inches. Dual and multilayer cores
have an inner core layer and an outer core layer, and multilayer
cores additionally have at least one intermediate core layer
disposed between the inner core layer and the outer core layer.
Inner core layers of the present invention preferably have a
diameter within the range having a lower limit of 0.5 inches or
0.75 inches or 1 inch and an upper limit of 1.25 inches or 1.4
inches or 1.55 inches or 1.57 inches or 1.58 inches. Outer core
layers of the present invention preferably have a thickness within
the range having a lower limit of 0.02 inches or 0.025 inches or
0.032 inches and an upper limit of 0.31 inches or 0.44 inches or
0.56 inches. The total thickness of intermediate core layer(s) of
the present invention is preferably within the range having a lower
limit of 0.02 inches or 0.025 inches or 0.032 inches and an upper
limit of 0.15 inches or 0.22 inches or 0.28 inches.
[0040] Golf ball cores of the present invention preferably have an
Atti compression of 110 or less, or 90 or less, or 80 or less, or
75 or less, or 70 or less, or 65 or less, or 60 or less, or 50 or
less. Compression is measured according to the procedure set forth
below. Golf ball cores of the present invention preferably have a
COR at 125 ft/s of at least 0.775, or at least 0.780, or at least
0.782, or at least 0.785, or at least 0.787, or at least 0.790, or
at least 0.795, or at least 0.800. COR is determined according to
the procedure set forth below. In a particular embodiment, the
present invention provides a golf ball core having an Atti
compression of 75 or less and a COR at 125 ft/s of at least 0.8. In
another particular embodiment, the present invention provides a
golf ball core having an Atti compression of 75 or less and a COR
at 125 ft/s of at least 0.798. In another particular embodiment,
the present invention provides a golf ball core having an Atti
compression of 60 or less and a COR at 125 ft/s of at least 0.785.
In another particular embodiment, the present invention provides a
golf ball core having an Atti compression of 50 or less and a COR
at 125 ft/s of at least 0.781, or at least 0.783, or at least
0.790.
[0041] Golf balls of the present invention preferably have at least
one core layer formed from a rubber composition of the present
invention. In a particular embodiment, the present invention
provides a golf ball having a single layer core formed from a
rubber composition of the present invention. In another particular
embodiment, the present invention provides a golf ball comprising a
dual core having an inner core layer and an outer core layer,
wherein the inner core layer is formed from a rubber composition of
the present invention. In another particular embodiment, the
present invention provides a golf ball comprising a dual core
having an inner core layer and an outer core layer, wherein the
outer core layer is formed from a rubber composition of the present
invention. In another particular embodiment, the present invention
provides a golf ball comprising a multilayer core having an inner
core layer, an outer core layer, and at least one intermediate core
layer, wherein the inner core layer is formed from a rubber
composition of the present invention. In another particular
embodiment, the present invention provides a golf ball comprising a
multilayer core having an inner core layer, an outer core layer,
and at least one intermediate core layer, wherein the outer core
layer is formed from a rubber composition of the present invention.
In another particular embodiment, the present invention provides a
golf ball comprising a multilayer core having an inner core layer,
an outer core layer, and at least one intermediate core layer,
wherein an intermediate core layer is formed from a rubber
composition of the present invention.
[0042] In yet another particular embodiment, the present invention
provides a wound golf ball comprising one or more core layers, an
elastomeric winding around the core, and a cover, wherein a rubber
composition of the present invention is present in at least one of
the core layer(s) and/or the elastomeric winding around the core.
Wound golf balls, including methods of their manufacture, are
further disclosed, for example, in U.S. Pat. No. 4,846,910, the
entire disclosure of which is hereby incorporated herein by
reference.
[0043] Golf ball cores of the present invention may include one or
more layers formed from a suitable material other than a rubber
composition of the present invention. Suitable core materials for
the golf balls disclosed herein include, but are not limited to,
natural and synthetic rubbers, such as polybutadiene, polyisoprene,
ethylene propylene rubber, ethylene propylene diene 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), butyl rubber, halobutyl rubber,
copolymers of isobutylene and para-alkylstyrene, halogenated
copolymers of isobutylene and para-alkylstyrene, copolymers of
butadiene with acrylonitrile, polychloroprene, alkyl acrylate
rubber, chlorinated isoprene rubber, and acrylonitrile chlorinated
isoprene rubber; metallocene polymers; acid copolymers and
ionomers; and combinations thereof.
[0044] Golf ball covers of the present invention include single,
dual, and multilayer covers, and preferably have an overall
thickness within the range having a lower limit of 0.01 inches or
0.02 inches or 0.025 inches or 0.03 inches or 0.04 inches or 0.045
inches or 0.05 inches or 0.06 inches and an upper limit of 0.07
inches or 0.075 inches or 0.08 inches or 0.09 inches or 0.1 inches
or 0.15 inches or 0.2 inches or 0.3 inches or 0.5 inches. Dual and
multilayer covers have an inner cover layer and an outer cover
layer, and multilayer covers additionally have at least one
intermediate cover layer disposed between the inner cover layer and
the outer cover layer. Inner cover layers of the present invention
preferably have a thickness within the range having a lower limit
of 0.01 inches or 0.02 inches or 0.025 inches and an upper limit of
0.05 inches or 0.15 inches or 0.2 inches. Outer cover layers of the
present invention preferably have a thickness of 0.01 inches or
0.02 inches or 0.025 inches and an upper limit of 0.05 inches or
0.15 inches or 0.2 inches. Intermediate cover layer(s) of the
present invention preferably have a thickness of 0.01 inches or
0.02 inches or 0.025 inches and an upper limit of 0.05 inches or
0.15 inches or 0.2 inches.
[0045] Golf ball covers of the present invention may include one or
more layers formed from a suitable material other than a rubber
composition of the present invention. The cover material is
preferably a tough, cut-resistant material, selected based on the
desired performance characteristics. Suitable cover materials for
the golf balls disclosed herein include, but are not limited to,
polyethylene, including, for example, low density polyethylene,
linear low density polyethylene, and high density polyethylene;
polypropylene; rubber-toughened olefin polymers; acid copolymers
which do not become part of an ionomeric copolymer; plastomers;
flexomers; styrene/butadiene/styrene block copolymers;
styrene/ethylene-butylene/styrene block copolymers; dynamically
vulcanized elastomers; ethylene vinyl acetates; ethylene methyl
acrylates; polyvinyl chloride resins; polyamides, amide-ester
elastomers, and graft copolymers of ionomer and polyamide,
including, for example, Pebax.RTM. thermoplastic polyether block
amides, commercially available from Arkema Inc; crosslinked
transpolyisoprene blends; polyurethanes; polyureas; polyester-based
thermoplastic elastomers, such as Hytrel.RTM., commercially
available from E. I. du Pont de Nemours and Company;
polyurethane-based thermoplastic elastomers, such as
Elastollan.RTM., commercially available from BASF; synthetic or
natural vulcanized rubber; ionomeric resins; and combinations
thereof. Suitable cover materials and constructions also include,
but are not limited to, those disclosed in U.S. Pat. Nos.
6,117,025, 6,767,940, and 6,960,630, the entire disclosures of
which are hereby incorporated herein by reference.
[0046] Commercially available ionomeric cover materials include,
but are not limited to, Surlyn.RTM. ionomer resins and DuPont.RTM.
HPF 1000 and HPF 2000, commercially available from E. I. du Pont de
Nemours and Company; and Iotek.RTM. ionomers, commercially
available from ExxonMobil Chemical Company. Also suitable are
blends of ionomers with thermoplastic elastomers. Suitable
ionomeric cover materials are further disclosed, for example, in
U.S. Pat. Nos. 6,653,382, 6,756,436, 6,894,098, 6,919,393, and
6,953,820, the entire disclosures of which are hereby incorporated
by reference.
[0047] Suitable polyurethane cover materials are further disclosed,
for example, in U.S. Pat. No. 6,756,436, the entire disclosure of
which is hereby incorporated herein by reference. When used as
cover materials, polyurethane and polyurea 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.
Light stable polyurethanes and polyureas are a preferred material
for single layer covers and the outer cover layer of dual and
multilayer covers. High modulus thermoplastics are a preferred
material for the inner cover layer of dual and multilayer
covers.
[0048] Golf ball cover materials optionally contain one or more
filler(s), such as the fillers given above for rubber compositions
of the present invention (e.g., titanium dioxide, barium sulfate,
etc.), and/or additive(s), such as coloring agents, fluorescent
agents, whitening agents, antioxidants, dispersants, UV absorbers,
light stabilizers, plasticizers, surfactants, viscosity modifiers,
compatibility agents, foaming agents, reinforcing agents, release
agents, and the like.
[0049] Golf balls of the present invention optionally include one
or more intermediate layer(s) disposed between the core and the
cover. When present, the overall thickness of the intermediate
layer(s) is generally within the range having a lower limit of 0.01
inches or 0.05 inches or 0.1 inches and an upper limit of 0.3
inches or 0.35 inches or 0.4 inches. Suitable intermediate layer
materials include, but are not limited to, natural rubbers, balata,
gutta-percha, cis-polybutadienes, trans-polybutadienes, synthetic
polyisoprenes, polyoctenamers, styrene-propylene-diene rubbers,
metallocene rubbers, styrene-butadiene rubbers,
ethylene-propylenes, chloroprene rubbers, acrylonitrile rubbers,
acrylonitrile-butadiene rubbers, styrene-ethylene block copolymers,
maleic anhydride or succinate modified metallocene catalyzed
ethylene copolymers, polypropylene resins, ionomer resins,
polyamides, polyesters, polyurethanes, polyureas, chlorinated
polyethylenes, polysulfide rubbers, fluorocarbons, and combinations
thereof.
[0050] Suitable golf ball constructions and materials are further
disclosed, for example, in U.S. Patent Application Publication Nos.
2003/0144087 and 2005/0164810, U.S. Pat. Nos. 5,688,119 and
5,919,100, and PCT Publications WO00/23519 and WO00/29129. The
entire disclosure of each of these references is hereby
incorporated herein by reference.
[0051] Golf balls of the present invention preferably have an
overall diameter within the range having a lower limit of 1.6 or
1.62 or 1.66 inches and an upper limit of 1.69 or 1.74 or 1.800
inches. More preferably, golf balls of the present invention have
an overall diameter of 1.68 inches. Golf balls of the present
invention preferably have an Atti compression of 120 or less, or
110 or less, or 105 or less. Golf balls of the present invention
preferably have a COR at 125 ft/s of at least 0.75, or at least
0.78, or at least 0.79.
[0052] The present invention is not limited by any particular
process for forming the golf ball layer(s). It should be understood
that the layer(s) can be formed by any suitable technique,
including injection molding, compression molding, casting, and
reaction injection molding.
EXAMPLES
[0053] It should be understood that the examples below are for
illustrative purposes only. In no manner is the present invention
limited to the specific disclosures therein.
[0054] Golf ball cores of the present invention were prepared by
mixing materials according to the formulations given in the Tables
below, and then molding and grinding the resulting compositions to
obtain 1.55 inch diameter spheres. The compression and COR of each
sphere was measured and compared to the compression and COR of
comparative spheres to determine SFI. The results are given in the
Tables below.
[0055] Compression, also referred to herein as "Atti compression,"
is measured according to a known procedure, using an Atti
compression test device, wherein a piston is used to compress a
ball against a spring. The travel of the piston is fixed and the
deflection of the spring is measured. The measurement of the
deflection of the spring does not begin with its contact with the
ball; rather, there is an offset of approximately the first 1.25 mm
(0.05 inches) of the spring's deflection. Very low stiffness cores
will not cause the spring to deflect by more than 1.25 mm and
therefore have a zero Atti 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.
[0056] COR is determined according to a known procedure wherein a
golf ball or golf ball subassembly (e.g., a golf ball core) is
fired from an air cannon at a given velocity (125 ft/s for purposes
of the present invention). Ballistic light screens are located
between the air cannon and the steel plate to measure ball
velocity. As the ball travels toward the steel plate, it activates
each light screen, and the time at each light screen is measured.
This provides an incoming transit time period proportional to the
ball's incoming velocity. The ball impacts the steel plate and
rebounds though the light screens, which again measure the time
period required to transit between the light screens. This provides
an outgoing transit time period proportional to the ball's outgoing
velocity. COR is then calculated as the ratio of the outgoing
transit time period to the incoming transit time period,
COR=T.sub.out/T.sub.in.
[0057] SFI is determined by the following procedure. A control line
is defined by the linear regression equation of COR vs. compression
for two or more control formulations. The regression equation is
used to calculate the COR of a theoretical control formulation at
the same compression as an example formulation. SFI is then
calculated as the COR of the example formulation minus the COR of
the theoretical control formulation at the same compression as the
example formulation. Thus, SFI is a positive number when the
example formulation is more resilient than the control line at the
same compression, and a negative number when the example
formulation is less resilient than the control line at the same
compression.
Examples 1-5
methyl p-benzoguinone as a Free Radical Scavenger
[0058] In Examples 1-5, rubber compositions of the present
invention were prepared by mixing SE BR-1220, methyl
p-benzoquinone, Perkadox.RTM. BC, SR526, zinc oxide, and barium
sulfate, in a Brabender mixer for 5-10 minutes. Comparative
compositions C1-C3 were similarly prepared, except that no
benzoquinone was added. The relative amount of each component used
is indicated in Table 1.
[0059] The rubber compositions of Examples 1-5 and C1-C3 were then
cured in a compression molding press at 335.degree. C. for 11
minutes to obtain spheres, which were subsequently ground to a
diameter of 1.55 inches.
[0060] Each of the resulting spheres was evaluated for Atti
compression and COR at 125 ft/sec. The SFI of each of Examples 1-5
was then determined by comparing the compression and COR of each
Example with the compression and COR of C1-C3, according to the SFI
procedure described above. The results for compression, COR, and
SFI are reported in Table 1. TABLE-US-00001 TABLE 1 Example No. 1 2
3 4 5 C1 C2 C3 Composition SE BR-1220* 100 100 100 100 100 100 100
100 (parts by weight) methyl p-benzoquinone 0.75 0.5 0.5 1 1 0 0 0
(parts by weight) Perkadox .RTM. BC** 3 2 3 4 3 0.5 0.5 0.5 (parts
by weight) SR526*** 25 25 25 25 25 20 25 30 (parts by weight) zinc
oxide 5 5 5 5 5 5 5 5 (parts by weight) barium sulfate 17.5 17.3
17.4 17.7 17.5 19 17.4 15.7 (parts by weight) P.sub.BQ/P.sub.FRI
0.25 0.25 0.17 0.25 0.33 P.sub.BQ = 0 P.sub.BQ = 0 P.sub.BQ = 0
Core Properties Compression 39 40 48 36 26 34 61 81 COR 0.783 0.780
0.785 0.784 0.776 0.773 0.791 0.801 SFI 0.006 0.003 0.003 0.009
0.007 -- -- -- *SE BR-1220 is a high cis-1,4 polybutadiene
commercially available from The Dow Chemical Company. **Perkadox
.RTM. BC is a dicumyl peroxide free radical initiator commercially
available from Akzo Nobel. ***SR526 is a zinc diacrylate-based
coagent commercially available from Sartomer Company, Inc.
Example 6
tetrachloro p-benzoguinone as a Free Radical Scavenger
[0061] In Example 6, a rubber composition of the present invention
was prepared by mixing SE BR-1220, tetrachloro p-benzoquinone,
Perkadox.RTM. BC, SR526, zinc oxide, and barium sulfate, in a
Brabender mixer for 5-10 minutes. Comparative compositions C4-C6
were similarly prepared, except that no benzoquinone was added. The
relative amount of each component used is indicated in Table 2.
[0062] The rubber compositions of Examples 6 and C4-C6 were then
cured in a compression molding press at 335.degree. C. for 11
minutes to obtain spheres, which were subsequently ground to a
diameter of 1.55 inches.
[0063] Each of the resulting spheres was evaluated for Atti
compression and COR at 125 ft/sec. The SFI of Example 6 was then
determined by comparing the compression and COR of Example 6 with
the compression and COR of C4-C6, according to the SFI procedure
described above. The results for compression, COR, and SFI are
reported in Table 2. TABLE-US-00002 TABLE 2 Example No. 6 C4 C5 C6
Composition SE BR-1220* 100 100 100 100 (parts by weight)
tetrachloro p-benzoquinone 0.5 0 0 0 (parts by weight) Perkadox
.RTM. BC** 2 0.5 0.5 0.5 (parts by weight) SR526*** 25 20 25 30
(parts by weight) zinc oxide 5 5 5 5 (parts by weight) barium
sulfate 17.3 19.0 17.3 15.7 (parts by weight) P.sub.BQ/P.sub.FRI
0.25 P.sub.BQ = 0 P.sub.BQ = 0 P.sub.BQ = 0 Core Properties
Compression 53 31 58 80 COR 0.790 0.770 0.786 0.797 SFI 0.008 -- --
-- *SE BR-1220 is a high cis-1,4 polybutadiene commercially
available from The Dow Chemical Company. **Perkadox .RTM. BC is a
dicumyl peroxide free radical initiator commercially available from
Akzo Nobel. ***SR526 is a zinc diacrylate-based coagent
commercially available from Sartomer Company, Inc.
[0064] 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.
[0065] 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.
* * * * *