Source: http://www.patentsencyclopedia.com/app/20120305159
Timestamp: 2016-10-28 03:16:14
Document Index: 661152464

Matched Legal Cases: ['Application No. 2007', 'Application No. 2007', 'Application No. 2007', 'Application No. 2007', 'Application No. 2007', 'art, 2', 'art, 2', 'art, 3', 'art, 4', 'art, 5', 'art\n2', 'art 2', 'art 2', 'arts 3', 'art 2', 'art 4', 'art 3', 'arts\n4', 'art 2', 'art 2', 'art 4', 'art 2', 'art 3', 'art 4', 'art 2', 'art 2']

RUBBER COMPOSITION AND PNEUMATIC TIRE USING THE SAME - Patent application
Patent application title: RUBBER COMPOSITION AND PNEUMATIC TIRE USING THE SAME
Shuichi Sakamoto (Kobe-Shi, JP)
Issei Nakakita (Kobe-Shi, JP)
USPC Class: 152541
Class name: Pneumatic tire or inner tube characterized by the structure of the bead portion of the tire apex or filler strip
Patent application number: 20120305159
It is possible to provide a rubber composition including a rubber
component, and 0.5 part by mass or more of at least any one of a terpene
based resin and a rosin-based resin based on 100 parts by mass of the
rubber component, wherein the rubber component contains 20 to 100% by
mass of a natural rubber component consisting of at least any one of a
natural rubber and a modified natural rubber, as well as the rubber
composition which can realize both of maintenance of properties desired
in various applications and improvement in processibility while a use
amount of a raw material derived from a petroleum source is reduced, and
a pneumatic tire using the same.Claims:
1. A pneumatic tire comprising: a bead apex having a rubber composition,
said rubber composition of the bead apex comprising a rubber component,
and at least any one of a terpene based resin, and a rosin-based resin at
0.5 to 15 part by mass, 60 to 120 parts by mass of silica, 5 parts by
mass or less of carbon black, and 0.1 to 0.8 part by mass of a peptizing
agent based on 100 parts by mass of said rubber component, wherein said
rubber component contains a natural rubber component consisting of at
least any one of a natural rubber and a modified natural rubber in a
range of 20 to 100% by mass; and a clinch rubber having a rubber
composition, said rubber composition of the clinch rubber comprising a
rubber component, and at least any one of a terpene based resin, and a
rosin-based resin at 0.5 to 20 part by mass, and 35 to 150 parts by mass
of silica based on 100 parts by mass of said rubber component, wherein
said rubber component of the clinch rubber comprises a natural rubber
component consisting of at least any one of a natural rubber and a
modified natural rubber in a range of 20 to 100% by mass.
2. The pneumatic tire according to claim 1, further comprising a base
tread having a rubber composition, said rubber composition of the base
tread comprising a rubber component, and at least any one of a terpene
based resin, and a rosin-based resin at 0.5 to 20 part by mass, and 35 to
150 parts by mass of silica based on 100 parts by mass of said rubber
component, wherein said rubber component of the base tread contains a
natural rubber component consisting of at least any one of a natural
rubber and a modified natural rubber in a range of 20 to 100% by mass.
3. The pneumatic tire according to claim 1, further comprising a tread
having a rubber composition, said rubber composition of the tread
comprising a rubber component, and at least any one of a terpene based
resin, and a rosin-based resin at 0.5 to 100 part by mass, 45 to 150
parts by mass of silica, and 5 parts by mass or less of carbon black,
wherein said rubber component contains a natural rubber component
consisting of at least any one of a natural rubber and a modified natural
rubber in a range of 20 to 100% by mass.
4. The pneumatic tire according to claim 1, further comprising a carcass
ply having a rubber composition, said rubber composition of the carcass
ply comprising a rubber component, and at least and one of a terpene
based resin, and a rosin-based resin at 0.5 to 15 part by mass, and 20 to
60 parts by mass of silica based on 100 parts by mass of said rubber
component, wherein said rubber component contains a natural rubber
5. The pneumatic tire according to claim 1, wherein the modified natural
rubber is an epoxidized natural rubber.
6. The pneumatic tire according to claim 1, wherein said rubber component
consists of said natural rubber component.Description:
[0001] This application is a Divisional of co-pending application Ser. No.
12/599,650 filed on Nov. 10, 2009, which is the national phase of PCT
International Application No. PCT/JP2008/054760 filed on Mar. 14, 2008,
and which claims priority to Application No. 2007-135650 filed in the
Japan on May 22, 2007; Application No. 2007-153053 filed in the Japan on
Jun. 8, 2007; Application No. 2007-153067 filed in the Japan on Jun. 8,
2007; Application No. 2007-164086 filed in the Japan on Jun. 21, 2007;
and Application No. 2007-164158 filed in the Japan on Jun. 21, 2007. The
entire contents of all of the above applications are hereby incorporated
[0002] The present invention relates to a rubber composition and a
pneumatic tire using the same.
[0003] Recently, with increased interest in environmental problems, a
method for reducing a use amount of a raw material derived from a
petroleum source has been studied in a variety of technical fields. A
half or more of a total weight of a tire being generally sold now is
constituted of a raw material being a petroleum source. For example,
since a tire for a general passenger automobile contains such as about
20% by mass of a synthetic rubber, about 20% by mass of carbon black, a
softening agent and a synthetic fiber, about 50% by mass or more of a
whole tire is constituted of a raw material of the petroleum source. In
addition, for the purpose of improving processibility by improvement in
stickiness and reduction in a viscosity, a stickiness imparting agent is
blended into the rubber composition for a tire and, as this stickiness
imparting agent, a resin derived from a petroleum source such as a
C5-based resin, a C9-based resin, and a phenol-based resin is generally
used. Then, development of a rubber for a tire using a raw material
derived from a natural source satisfying the required properties
equivalent to or exceeding those when a raw material derived from a
petroleum source is used, is desired.
[0004] Here, for the purpose of providing a tread rubber composition
satisfying industrial workability, and by which performance excellent in
the gripping property is obtained, a tread rubber composition in which
100 to 150 parts by weight of a terpene-based resin is compounded based
on 100 parts by weight of a diene-based rubber is known. In addition, the
technique capable of providing a rubber composition for a tire, which is
a substitute for a petroleum-based aroma oil, and gives a small load on
the environment, by containing 50 parts by weight or more of a natural
rubber or a polyisoprene rubber among diene-based rubber components, and
compounding 1 to 50 parts by weight of a terpene resin having a specified
dynamic viscosity, is also known. Further, for the similar object, a
rubber composition for a tire tread containing 50 parts by weight or more
of a natural rubber among diene-based rubber components, and containing a
reinforcing filler containing 60% by weight or more of silica, and in
which 0.5 to 15 parts by weight of a phenol-modified terpene resin having
a specified softening point, a specified hydroxy value and a specified
dynamic viscosity is compounded therein, is also known. However, since
these rubber compositions reduce a load on the environment by compounding
a large amount of a natural source material without compounding a
petroleum-based resin, but a rubber composition for a side wall, and
performance required by this are not considered at all, and
processibility is not sufficient. However, these rubber compositions
reduce a load on the environment by compounding a large amount of a
natural source material without compounding a petroleum-based resin, but
application of various members (a clinch rubber, a base tread part
adjacent to an inner side of a cap tread part, a rubber composition for a
carcass ply, a bead apex etc.), and performance required for each of them
are not considered at all, and processibility is not sufficient.
[0005] In addition, Japanese Patent Laying-Open No. 11-11106 (Patent
Document 1) discloses a tubeless tire without an inner liner using a
rubber composition for a case cord covering rubber layer, which contains
1 to 10 parts by weight of a stickiness imparting agent based on 100
parts by weight of a rubber component consisting of a diene-based rubber
and bromide of an isobutylene/p-methylstyrene copolymer and, as this
stickiness imparting agent, a terpene resin, and a rosin derivative are
exemplified. According to Patent Document 1, it is described that
adhesiveness with other tire member is excellent by using such the rubber
[0006] In addition, Japanese Patent Laying-Open No. 2004-2584 (Patent
Document 2) discloses a rubber composition in which 40 to 500 parts by
weight of a filler and 15 parts by weight or more of a resin are
compounded based on 100 parts by weight of a rubber component and, as
this resin, a terpene resin and a rosin resin are exemplified. According
to Patent Document 2, it is described that both of wet gripping
performance and abrasion resistance can be realized by adopting such the
composition, and using this in a tread part.
[0007] Further, Japanese Patent Laying-Open No. 2006-63093 (Patent
Document 3) discloses a rubber composition for a tread, containing 8
parts by weight or more of a resin, and a filler consisting of 80% by
weight or more of a white filler based on 100 parts by weight of a rubber
component containing 80% by weight or more of a natural rubber and/or an
epoxidized natural rubber and, as this resin, a terpene resin, an
aromatic modified terpene resin, and a rosin resin are exemplified.
According to Patent Document 3, it is described that a content of a
source other than a petroleum can be enhanced and, at the same time, the
previous performance can be similarly preserved.
[0008] However, in the inventions disclosed in any one of Patent Documents
1 to 3, the aforementioned applications of various members and
performance required for this are not considered at all, and it is hard
to say that processibility is sufficient. [0009] Patent Document 1:
Japanese Patent Laying-Open No. 11-11106 [0010] Patent Document 2:
Japanese Patent Laying-Open No. 2004-2584 [0011] Patent Document 3:
Japanese Patent Laying-Open No. 2006-63093
[0012] The present invention was done in order to solve the aforementioned
problems, and an object thereof is to provide a rubber composition in
which both of maintenance of properties desired in various applications,
and improvement in processibility can be realized while a use amount of a
raw material derived from a petroleum source is reduced, and a pneumatic
tire using the same.
[0013] The rubber composition of the present invention includes a rubber
component, and 0.5 part by mass or more of at least any one of a
terpene-based resin and a rosin-based resin based on 100 parts by mass of
the rubber component, wherein the rubber component contains a natural
rubber component consisting of at least any one of a natural rubber and a
[0014] Here, it is preferable that the modified natural rubber is an
epoxidized natural rubber.
[0015] It is preferable that the rubber component in the rubber
composition of the present invention consists of the natural rubber
[0016] It is preferable that the rubber composition of the present
invention is any one of the following:
[0017] It is for a clinch rubber.
[0018] It is for a base tread.
[0019] It is for a tread, and further includes 45 parts by mass or more of
silica, and 5 parts by mass or less of carbon black based on 100 parts by
mass of the rubber component.
[0020] It is for a carcass ply, and further includes 20 to 60 parts by
mass of silica based on 100 parts by mass of the rubber component.
[0021] It is for a bead apex, and further includes 60 parts by mass or
more of silica, 5 parts by mass or less of carbon black, and 0.1 to 0.8
part by mass of a peptizer based on 100 parts by mass of the rubber
[0022] The present invention also provides a pneumatic tire which is any
[0023] It is provided with a clinch rubber consisting of the rubber
component of the present invention for a clinch rubber.
[0024] It is provided with a base tread part consisting of the rubber
component of the present invention for a base tread.
[0025] It is provided with a tread rubber consisting of the rubber
component of the present invention for a tread.
[0026] It is provided with the rubber composition of the present invention
for a carcass ply, and a carcass ply constituted of a cord for a tire
embedded in the rubber composition.
[0027] It is provided with a bead apex consisting of the rubber
composition of the present invention for a bead apex.
[0028] According to the present invention, a rubber composition which can
realize both of maintenance of properties desired in various applications
(rigidity, hardness, mechanical strength etc. when used in the clinch
rubber, rolling resistance property, operation stability etc. when used
in the base tread, gripping performance, durability including abrasion
resistance, rolling resistance property, heat producing property etc.
when used in the tread, and hardness, breakage property etc. when used in
the bead apex), and improvement in processibility while a use amount of a
tire using the same can be provided.
[0029] FIG. 1 is a schematic cross-sectional view showing one example of
the pneumatic tire of the present invention.
[0030] In the FIGURE, 1 is a tire, 2 is a tread part, 2a is a cap tread
part, 2b is a base tread part, 3 is a side wall part, 4 is a bead part, 5
is a bead core, 6 is a carcass, 6a is a carcass ply, 7 is a belt layer, 8
is a bead apex rubber, 9 is an inner liner rubber, and 4G is a clinch
[0031] The rubber composition of the present invention includes a rubber
modified natural rubber in a range of 20 to 100% by mass. Such the rubber
composition of the present invention can be suitably used for a clinch
rubber or a base tread. In addition, the rubber composition of the
present invention, when it further includes 45 parts by mass or more of
mass of the rubber component, can be suitably used for a tread. In
addition, the rubber composition of the present invention, when it
further includes 20 to 60 parts by mass of silica based on 100 parts by
mass of the rubber component, can be suitably used for a carcass ply.
Further, the rubber composition of the present invention, when it further
includes 60 parts by mass or more of silica, 5 parts by mass or less of
carbon black, and 0.1 to 0.8 part by mass of a peptizer, can be suitably
used for a bead apex.
[0032] The rubber composition of the present invention contains a rubber
the rubber component. In addition, the rubber component used in the
present invention contains a natural rubber component consisting at least
any one of a natural rubber (NR) and a modified natural rubber
(hereinafter, simply also referred to as "natural rubber component") in a
range of 20 to 100% by mass.
[0033] In the rubber composition of the present invention, the rubber
component contains a natural rubber component consisting at least any one
of a natural rubber and a modified natural rubber (ENR). That is, the
natural rubber component in the present invention may consist only of a
natural rubber, may consist only of a modified natural rubber, or may
include both of them.
[0034] As the natural rubber used in the present invention, any natural
rubber is included as far as it is known as a natural rubber, and a place
of origin and the like are not limited. Such the natural rubber contains
mainly cis 1,4 polyisoprene, and may contain trans 1,4 polyisoprene
depending on the required property. Therefore, the natural rubber
includes, in addition to a natural rubber containing mainly cis 1,4
polyisoprene, a natural rubber containing mainly trans 1,4 isoprene such
as balata being one kind of Sapotaceae rubber plants produced in South
America. The natural rubber component in the present invention can
contain one kind or two or more kinds of such the natural rubbers (i.e.
one component or two or more components). As such the natural rubber, for
example, a natural rubber of a grade such as RSS#3, and TSR can be
[0035] The modified natural rubber used in the present invention refers to
a rubber in which the aforementioned rubber is modified or purified, and
examples include such as an epoxidized natural rubber (ENR), a
deproteinized natural rubber (DPNR), and a hydrogenated natural rubber.
The natural rubber component in the present invention may contains one
kind or two or more kinds of such the modified natural rubbers. It is
preferable that the natural rubber component in the present invention
contains, as a modified natural rubber, an epoxidized natural rubber
[0036] The epoxidized natural rubber is one kind of modified natural
rubbers in which an unsaturated double bond of the natural rubber is
epoxidized, and a molecular cohesive force is enhanced by an epoxy group
which is a polar group. For this reason, a glass transition temperature
(Tg) is higher than that of the natural rubber, and a mechanical
strength, abrasion resistance, and air permeability resistance are
excellent. As such the epoxidized natural rubber, a commercially
available epoxidized natural rubber such as ENR25 (manufactured by
Kumpulan Guthrie Berhad) (epoxidization rate: 25%), and ENR50
(manufactured by Kumpulan Guthrie Berhad) (epoxidization rate: 50%) may
be used, and an epoxidized natural rubber may be used. A method of
epoxidizing a natural rubber is not particularly limited, and includes
such as a chlorohydrin method, a direct oxidation method, a hydrogen
peroxide method, an alkylhydroperoxide method, and a peracid method.
Examples of the peracid method include a method of reacting organic
peracid such as peracetic acid and performic acid as an epoxidizing agent
with an emulsion of the natural rubber.
[0037] It is preferable that an epoxidization rate of the epoxidized
natural rubber (ENR) is 5 mol % or more. Here, the epoxidization rate
means a ratio of the number of epoxidized double bonds among the total
number of double bonds in the natural rubber before epoxidization ((the
number of epoxidized double bonds)/(the number of double bonds before
epoxidization)), and is obtained by, for example, titration analysis, or
nuclear magnetic resonance (NMR) analysis. When the epoxidization rate of
the epoxidized natural rubber (ENR) is less than 5 mol %, since a glass
transition temperature of the epoxidized natural rubber (ENR) is low, a
rubber hardness of the rubber composition is reduced. For this reason,
there is a tendency that when a rubber composition in which the
epoxidization rate of the epoxidized natural rubber is less than 5 mol %
like this is used for a clinch rubber or a tread, durability and fatigue
resistance of a pneumatic tire using the same are reduced, when the
composition is used for a base tread, operation stability of a pneumatic
tire using the same is reduced and, when the composition is used for a
bead apex, it is hard to obtain a high harness, high durability, high
fatigue resistance and high rolling resistance of a pneumatic tire using
the same. In addition, when the rubber composition of the present
invention is used in the clinch rubber, the base tread, or the tread, the
epoxidization rate of the epoxidized natural rubber is more preferably 10
mol % or more and, when the rubber composition of the present invention
is used in the bead apex, the epoxidization rate of the epoxidized
natural rubber is more preferably 25 mol % or more.
[0038] In addition, when the rubber composition of the present invention
is used in the clinch rubber, the base tread, or the tread, the
epoxidization rate of the epoxidized natural rubber is preferably 65 mol
% or less, more preferably 60 mol % or less. In this case, when the
epoxidization rate of the epoxidized natural rubber exceeds 65 mole %,
there is a tendency that a mechanical strength is reduced due to a too
hard rubber composition. In addition, when the rubber composition of the
present invention is used in the bead apex, the epoxidizaiton rate of the
epoxidized natural rubber is preferably 50 mol % or less, more preferably
30 mole % or less. In this case, when the epoxidization rate of the
epoxidized natural rubber (ENR) exceeds 50 mol %, there is a tendency
that a hardness is excessively increased, and bending fatigue resistance
is reduced in a pneumatic tire provided with the bead apex using the
[0039] More typically, examples of the epoxidized natural rubber (ENR)
include an epoxidized natural rubber having the epoxidization rate of 25
mol %, and an epoxidized natural rubber having the epoxidization rate of
[0040] In the present invention, a content of the natural rubber component
in the rubber component is 20% by mass or more. When the content of the
natural rubber component in the rubber component is less than 20% by
mass, the effect of reducing a use amount of a raw material derived from
a petroleum source is not sufficiently obtained. The content of the
natural rubber component in the rubber component is preferably 30% by
mass or more, more preferably 40% by mass or more. In addition,
particularly, when the rubber composition of the present invention is
used in a carcass ply, the content of the natural rubber component in the
rubber component is preferably 50% by mass or more, more preferably 70%
by mass or more, particularly preferably 90% by mass or more. From the
viewpoint that the effect of reducing a use amount of a raw material
derived from a petroleum source is better, although it is preferable that
the content of the natural rubber component in the rubber component is
100% by mass (that is, the rubber component consists of the natural
rubber component), for example, the content of the natural rubber
component in the rubber component may be 50% by mass or less, further 30%
by mass or less, and a rubber other than the natural rubber component as
a remaining part in the rubber component may be compounded.
[0041] In addition, when the rubber composition of the present invention
is used in the carcass ply, it is preferable that the aforementioned
rubber component contains a natural rubber component consisting of 30 to
70% by mass of a natural rubber (NR), and 30 to 70% by mass of a modified
[0042] In addition, the rubber component may contain a rubber derived from
a petroleum source in such a range that the effect of the present
invention is not deteriorated. Examples of the rubber derived from a
petroleum source include such as a styrene butadiene rubber (SBR), a
butadiene rubber (BR), a styrene isoprene copolymer rubber, an isoprene
rubber (IR), a butyl rubber (BR), a chloroprene rubber (CR), an
acrylonitrile butadiene rubber (NBR), a halogenated butyl rubber (X-IIR),
and a halide of a copolymer of isoprene and p-methylstyrene. Among them,
SBR, BR, and IR are preferable in that, in the case where a hardness of
the rubber composition of the present invention can be higher, and the
rubber composition of the present invention is used in the clinch rubber,
particularly better durability and fatigue resistance can be imparted to
a pneumatic tire using this, in the case where the rubber composition of
the present invention is used in the base tread, durability can be
imparted to a pneumatic tire using this and, in the case where the rubber
composition in the present invention is used in the tread, a mechanical
strength can be imparted to a pneumatic tire using this. Further, in the
case where the rubber composition of the present invention is used in the
bead apex, a high hardness, high durability, high fatigue resistance, and
high rolling resistance can be imparted to a pneumatic tire using this.
<Terpene-Based Resin and Rosin-Based Resin>
[0043] The rubber composition of the present invention contains at least
any one of a terpene-based resin and a rosin-based resin as a resin using
a natural material. That is, the rubber composition of the present
invention may contain only a terpene-based resin, may contain only a
rosin-based resin, or may contain both of them. Alternatively, the
composition may contain a plurality of kinds of terpene-based resins, and
rosin-based resins.
[0044] The "terpene-based resin" as used herein refers to a resin obtained
by polymerizing, as a main monomer, a terpene compound contained in a
plant essential oil obtained from generally a leaf, a tree, a root or the
like of a plant. The terpene compound is generally a polymer of isoprene
(C5H8), and is a compound in which terpene classified into such
as monoterpene (C10H16), sesquiterpene (C15H24), and
diterpene (C20H32) is a fundamental skeleton. Examples include
such as α-pinene, β-pinene, dipentene, limonene, myrcene,
allo-ocimene, ocimene, α-phellandrene, α-terpinene,
γ-terpinene, terpinolene, 1,8-cineole, 1,4-cineole,
α-terpineol, β-terpineol, γ-terpineol, camphene,
tricyclenme, sabinene, paramenthadienes, and carenes.
[0045] The terpene-based resin in the present invention also includes, in
addition to a terpene resin such as an α-pinene resin, a
β-pinene resin, a limonene resin, a dipentene resin, and a
β-pinene/limonene resin from a raw material of the aforementioned
terpene compound, an aromatic compound-modified terpene resin from a raw
material of the terpene compound and an aromatic compound, a
terpenephenol resin from a raw material of the terpene compound and a
phenol-based compound, and a hydrogenated terpene resin in which the
terpene resin was hydrogenation-treated subjected to hydrotreatment.
Here, examples of the aromatic compound which isbeing a raw material of
the aromatic terpene resin in the present invention include such as
styrene, α-methylstyrene, vinyltoluene, and divinyltoluene, and
examples of the phenol-based compound which is being a raw material of
the terpenephenol resin include such as phenol, bisphenol A, cresol, and
[0046] As such the terpene-based resin, a commercially available product
such as PX300N (manufactured by YASUHARA CHEMICAL CO., LTD.), and PX1000N
(manufactured by YASUHARA CHEMICAL CO., LTD.) can be suitably used.
[0047] When the rubber composition of the present invention contains the
terpene-based resin, the terpene-based resin has a softening point of
preferably 150° C. or lower, more preferably 120° C. or
lower. When the softening point exceeds 150° C., there is a
tendency that the resin is dispersed with difficulty, and stickiness is
[0048] In addition, the "rosin-based resin" as used herein includes a
hydrogenated rosin resin, a modified rosin resin such as a maleic
acid-modified rosin resin, and a rosin-modified phenol resin, and a
disproportionated rosin resin obtained by disproportionating rosin ester
such as rosin glycerin ester, or a rosin resin, in addition to a
naturally occurring rosin resin (polymerized rosin) such as gum rosin,
wood rosin, and tall oil rosin containing, as a main component, resin
acid such as abietic acid, neoabietic acid, parastrinic acid, levopimaric
acid, pimaric acid, isopimaric acid, and dehydroabietic acid, obtained by
processing rosin.
[0049] As such the rosin-based resin, a commercially available product
such as tall oil rosin TP90B (manufactured by Harima Chemicals, Inc.) can
be suitably used.
[0050] When the rubber composition of the present invention contains the
rosin-based resin, the resin-based resin has a softening point of
[0051] The rubber composition of the present invention contains at least
any one selected from the terpene-based resin and the rosin-based resin
at 0.5 part by mass or more based on 100 parts by mass of the rubber
component. Here, when the composition contains both of the terpene-based
resin and the rosin-based resin, a total amount of them is 0.5 part by
mass or more based on 100 parts by mass of the rubber component. When the
content of at least any one selected from the terpene-based resin and the
rosin-based resin is less than 0.5 part by mass based on 100 parts by
mass of the rubber component, there is a disadvantage that stickiness
necessary for processing is deficient.
[0052] In addition, in the rubber composition of the present invention,
when the rubber composition is used in the clinch rubber or the base
tread, the aforementioned content of at least any one selected from the
terpene-based resin and the rosin-based resin is preferably 20 parts by
weight or less, more preferably 15 parts by weight or less based on 100
parts by mass of the rubber component. When the rubber composition is
used in the clinch rubber or the base tread, in the case where the
rosin-based resin exceeds 20 parts by mass based on 100 parts by mass of
the rubber component, there is a tendency that a hardness and a
mechanical strength required for a clinch or a base tread are deficient.
[0053] In addition, in the rubber composition of the present invention,
when the rubber composition is used in the tread, the aforementioned
rosin-based resin is preferably 100 parts by mass or less, more
preferably 70 parts by mass or less based on 100 parts by mass of the
rubber component. When the rubber composition is used in the tread, in
the case where the content of at least any one selected from the
terpene-based resin and the rosin-based resin exceeds 100 parts by mass
based on 100 parts by mass of the rubber component, there is a tendency
that stickiness becomes excessively high, and processibility is
conversely deteriorated.
[0054] In addition, in the rubber composition of the present invention,
when the rubber composition is used in the carcass ply, the
aforementioned content of at least any one of the terpene-based resin and
the rosin-based resin (particularly terpene-based resin) is preferably 15
parts by mass or less based on 100 parts by mass of the rubber component.
When the rubber composition is used in the carcass ply, in the case where
the content of at least any one of the terpene-based resin and the
rosin-based resin exceeds 15 parts by mass based on 100 parts by mass of
the rubber component, tensile property is inferior. When the rubber
composition is used in the carcass ply, at least any one of the
terpene-based resin and the rosin-based resin is contained preferably at
2 to 10 parts by mass, more preferably 3 to 5 parts by mass based on 100
parts by mass of the rubber component.
[0055] Further, in the rubber composition of the present invention, when
the rubber composition is used in the bead apex, the aforementioned
rosin-based resin is preferably 15 parts by mass or less, more preferably
10 parts by mass or less based on 100 parts by mass of the rubber
component. When the rubber composition is used in a bead apex, in the
case where the content of at least any one selected from the
terpene-based resin and the rosin-based resin exceeds 15 parts by mass
that a hardness is reduced. When the rubber composition is used in the
bead apex, from a viewpoint that a tacking force is maintained optimally,
the content of at least any one selected from the terpene-based resin and
the rosin-based resin is preferably 0.5 part by mass or more, more
preferably 2 parts by mass or more based on 100 parts by mass of the
[0056] It is preferable that silica is further contained in the rubber
composition of the present invention. Silica functions as a reinforcing
filler and, by compounding silica, a tensile strength can be improved. In
addition, since silica is derived from a source other than a petroleum, a
use amount of a raw material derived from a petroleum source in the
rubber composition can be reduced as compared with, for example, the case
where a reinforcing agent derived from a petroleum source such as carbon
black is compounded as a main reinforcing agent.
[0057] When silica is contained, it is preferable that silica having a BET
specific surface area of 50 m2/g or more is used, and it is more
preferable that silica having a BET specific surface area of 80 m2/g
or more is used. When silica having a BET specific surface area of less
than 50 m2/g is used, there is a tendency that a sufficient hardness
is not obtained. In addition, a BET specific area of silica is preferably
500 m2/g or less, more preferably 300 m2/g or less. When silica
having a BET specific surface area exceeding 500 m2/g is used, there
is a tendency that processibility of the rubber is reduced. The
aforementioned BET specific surface area of silica can be measured by,
for example, the method according to ASTM-D-4820-93.
[0058] When silica is contained, a content thereof is not particularly
limited, but when the rubber composition of the present invention is used
in the clinch rubber or the base tread, the content is 35 parts by mass
or more, preferably 45 parts by mass or more based on 100 parts by mass
of the rubber component. When a content of silica is less than 35 parts
by mass based on 100 parts by mass of the aforementioned rubber
component, there is a tendency that a sufficient strength as a clinch
rubber or a base tread is not obtained, and there is a tendency that a
particularly sufficient tensile strength is not obtained. In addition,
when the rubber composition of the present invention is used in the
clinch rubber or the base tread, the content of silica is preferably 150
parts by mass or less, more preferably 130 parts by mass or less based on
100 parts by mass of the rubber component. When the rubber composition of
the present invention is used in the clinch rubber or the base tread, in
the case where the content of silica exceeds 150 parts by mass based on
100 parts by mass of the rubber component, there is a tendency that
processibility of the rubber is reduced and, at the same time, heat
generation of the rubber at running becomes high.
[0059] In addition, when the rubber composition of the present invention
is used in the tread, a content of silica is 45 parts by mass or more,
preferably 60 parts by mass or more based on 100 parts by mass of the
aforementioned rubber component. When the content of silica is less than
45 parts by mass based on 100 parts by mass of the rubber component,
there is a tendency that a sufficient strength as a tread rubber is not
obtained, and a particularly sufficient tensile strength is not obtained.
In addition, when the rubber composition of the present invention is used
in the tread, the content of silica is preferably 150 parts by mass or
less, more preferably 130 parts by mass or less based on 100 parts by
mass of the rubber component. When the rubber composition of the present
invention is used in the tread, in the case where the content of silica
exceeds 150 parts by mass based on 100 parts by mass of the rubber
component, there is a tendency that processibility of the rubber is
reduced and, at the same time, heat generation at running becomes high in
a tread rubber using the rubber composition.
[0060] In addition, when the rubber composition of the present invention
is used in the bead apex, the content of silica is preferably 60 parts by
mass or more based on 100 parts by mass of the aforementioned rubber
component. When the rubber composition of the present invention is used
in the bead apex, in the case where the content of silica is less than 60
parts by mass based on 100 parts by mass of the rubber component, there
is a tendency that a sufficient hardness is not obtained in the resulting
bead apex, and particularly there is a possibility that a sufficient
tensile strength is not obtained. In addition, when the rubber
composition of the present invention is used in the bead apex, the
content of silica is preferably 120 parts by mass or less, more
preferably 100 parts by mass or less based on 100 parts by mass of the
aforementioned rubber component. When the content of silica exceeds 120
is a tendency that a breakage strength is reduced.
[0061] Silica may be silica prepared by a wet method, or silica prepared
by a dry method. In addition, examples of a preferable commercially
available product include such as Ultrasil VN2 (manufactured by Evonik
Degussa Japan. Co., Ltd.) (BET specific surface area: 125 m2/g), and
Ultrasil VN3 (manufactured by Evonik Degussa Japan. Co., Ltd.) (BET
specific surface area: 210 m2/g).
[0062] When silica is contained in the rubber composition of the present
invention, it is preferable that a silane coupling agent together with
silica is compounded. As the silane coupling agent, the previously known
silane coupling agent can be used, and examples include sulfide-based
silane coupling agents such as bis(3-triethoxysilylpropyl)tetrasulfide,
bis(4-triethoxysilylbutyl)tetrasulfide,
bis(4-trimethoxysilylbutyl)tetrasulfide,
bis(2-triethoxysilylethyl)trisulfide,
bis(4-triethoxysilylbutyl)trisulfide,
bis(3-trimethoxysilylpropyl)trisulfide,
bis(2-trimethoxysilylethyl)trisulfide,
bis(4-trimethoxysilylbutyl)trisulfide,
bis(2-triethoxysilylethyl)disulfide, bis(4-triethoxysilylbutyl)disulfide,
bis(3-trimethoxysilylpropyl)disulfide,
bis(2-trimethoxysilylethyl)disulfide,
bis(4-trimethoxysilylbutyl)disulfide,
3-trimethoxysilylpropyl-N,N-dimethylthiocarbamoyl tetrasulfide,
2-triethoxysilylethyl-N, N-dimethylthiocarbamoyl tetrasulfide,
2-trimethoxysilylethyl-N,N-dimethylthiocarbamoyl tetrasulfide,
3-trimethoxysilylpropylbenzothiazolyl tetrasulfide,
3-triethoxysilylpropylbenzothiazole tetrasulfide, 3-trimethoxysilylpropyl
methacrylate monosulfide, 3-trimethoxysilylpropyl methacrylate
monosulfide; mercapto-based silane coupling agents such as
2-mercaptoethyltrimethoxysilane, and 2-mercaptoethyltriethoxysilane;
vinyl-based silane coupling agents such as vinyltriethoxysilane, and
vinyltrimethoxysilane; amino-based silane coupling agents such as
3-(2-aminoethyl)aminopropyltriethoxysilane, and
3-(2-aminoethyl)aminopropyltrimethoxysilane; glycidoxy-based silane
coupling agents such as γ-glycidoxypropyltriethoxysilane,
γ-glycidoxypropylmethyldiethoxysilane, and
γ-glycidoxypropylmethyldimethoxysilane; nitro-based silane coupling
agents such as 3-nitropropyltrimethoxysilane, and
3-nitropropyltriethoxysilane; chloro-based silane coupling agents such as
3-chloropropyltrimethoxysilane, 3-chloropropyltriethoxysi lane,
2-chloroethyltrimethoxysilane, and 2-chloroethyltriethoxysilane. These
silane coupling agents may be used alone, or may be used by combining two
[0063] Among them, Si69 (manufactured by Evonik Degussa Japan. Co., Ltd.)
(bis(3-triethoxysilylpropyl)tetrasulfide), and Si266 (manufactured by
Evonik Degussa Japan. Co., Ltd.) (bis(3-triethoxysilylpropyl)disulfide)
are preferably used based on the reason of better processibility.
[0064] When the silane coupling agent is further contained, a content
thereof is not particularly limited, but is preferably 4 parts by mass or
more, more preferably 6 parts by mass or more based on 100 parts by mass
of silica. When the content of the silane coupling agent is less than 4
parts by mass based on 100 parts by mass, there is a tendency that a
rubber strength is reduced. In addition, the content of the silane
coupling agent is preferably 20 parts by mass, more preferably 15 parts
by mass based on 100 parts by mass of silica. When the content of the
silane coupling agent exceeds 20 parts by mass based on 100 parts by mass
of silica, the effect of improving kneading and extrusion processibility
of the rubber is small and, on the other hand, the cost is increased,
being not economical, and there is a tendency that a rubber strength is
[0065] The rubber composition of the present invention may further contain
carbon black as a reinforcing agent in such a range that the effect of
the present invention is not deteriorated. By compounding of carbon
black, a better mechanical strength is imparted, but since carbon black
is generally derived from a petroleum source, in order to reduce a use
amount of a raw material derived from a petroleum source, it is
preferable that a compounding amount of carbon black is 5 parts by mass
or less, further 3 parts by mass or less, further 2 parts by mass or less
based on 100 parts by mass of the rubber component. When the rubber
composition of the present invention is used in the tread, usually,
carbon black is compounded as a reinforcing agent.
[0066] On the other hand, when carbon black is compounded, in the case
where the rubber composition of the present invention is used in the
clinch rubber, the base tread, or the tread, the compounding amount of
carbon black is preferably 10 parts by mass or more, more preferably 15
parts by mass or more based on 100 parts by mass of the rubber
composition in that the effect of improving a mechanical strength due to
compounding of carbon black is obtained better. In addition, based on the
similar reason, when the rubber composition of the present invention is
used in the carcass ply, the compounding amount of carbon black is
preferably 5 parts by mass or more, more preferably 10 parts by mass or
more based on 100 parts by mass of the rubber component. Further, based
on the similar reason, when the rubber composition of the present
invention is used in the bead apex, the compounding amount of carbon
black is preferably 3 parts by mass or more, more preferably 5 parts by
mass or more based on 100 parts by mass of the rubber component.
[0067] Examples of a preferable commercially available product of carbon
black include Show Black N220 (manufactured by Cabot Japan K.K.).
<Peptizing Agent>
[0068] In addition, when the rubber composition of the present invention
is used in the bead apex, it is preferable that a peptizing agent is
further contained. The peptizing agent is also called peptizer or
mastication accelerator, and is added in order to chemically cut a rubber
molecule of a raw material unvulcanized rubber to accelerate
plasticization, and promote reduction in a viscosity of the rubber to
shorten a mastication working time. As the peptizing agent, the
previously known appropriate peptizing agent such as an aromatic
mercaptan compound, a disulfide-based compound and a zinc salt thereof,
organic peroxide, a nitro compound, and a nitroso compound can be used.
In the rubber composition for the bead apex of the present invention, the
peptizing agent is compounded at 0.1 to 0.8 part by mass based on 100
parts by mass of the aforementioned rubber component.
<Other Compounding Ingredient>
[0069] In the rubber composition of the present invention, in addition to
the aforementioned components, other compounding ingredient having been
previously used in the rubber industry, for example, a vulcanizing agent,
stearic acid, a vulcanization accelerator, a vulcanization accelerator
auxiliary agent, an oil, a hardened resin, a wax, and an aging preventing
agent may be compounded.
[0070] As the vulcanizing agent, organic peroxide or a sulfur-based
vulcanizing agent can be used and, as the organic peroxide, for example,
benzoyl peroxide, dicumyl peroxide, di-t-butyl peroxide, t-butylcumyl
peroxide, methyl ethyl ketone peroxide, cumene hydroperoxide,
2,5-dimethyl-2,5-di(t-butylperoxy)hexyne-3 or
1,3-bis(t-butylperoxypropyl)benzene, di-t-butylperoxy-diisopropylbenzene,
t-butylperoxybenzene, 2,4-dichlorobenzoyl peroxide,
1,1-di-t-butylperoxy-3,3,5-trimethylsiloxiane, and
n-butyl-4,4-di-t-butylperoxyvalerate can be used. Among them, dicumyl
peroxide, t-butylperoxybenzene and bi-t-butylperoxy-diisopropylbenzene
are preferable. In addition, as the sulfur-based vulcanizing agent, for
example, sulfur, and morpholine disulfide can be used. Among them, sulfur
is preferable. These vulcanizing agents may be used alone, or may be used
by combining two or more kinds.
[0071] As the vulcanizing accelerator, an accelerator containing at least
one of sulfenamide-based, thiazole-based, thiuram-based, thiourea-based,
guanidine-based, dithiocarbamic acid-based, aldehyde-amine-based or
aldehyde-ammonia-based, imidazoline-based, and xanthate-based
vulcanization accelerators can be used. As the sulfenamide-based
vulcanization accelerators, sulfenamide-based compounds such as CBS
(N-cyclohexyl-2-benzothiazylsulfenamide), TBBS
(N-tert-butyl-2-benzothiazylsulfenamide), N,
N-dicyclohexyl-2-benzothiazylsulfenamide,
N-oxydiethylene-2-benzothiazylsulfenamide, and N,
N-diisopropyl-2-benzothiazolesulfenamide can be used. As the
thiazole-based vulcanization accelerator, thiazole-based compounds such
as MBT (2-mercaptobenzothiazole), MBTS (dibenzothiazyl disulfide), a
sodium salt, a zinc salt or a copper salt of 2-mercaptobenzothiazole, a
cyclohexylamine salt, 2-(2,4-dinitrophenyl)mercaptobenzothiazole, and
2-(2,6-diethyl-4-morpholinothio)benzothiazole can be used. As the
thiuram-based vulcanization accelerator, thiuram-based compounds such as
TMTD (tetramethylthiuram disulfide), tetraethylthiuram disulfide,
tetramethylthiuram monosulfide, dipentamethylenethiuram disulfide,
dipentamethylenethiuram monosulfide, dip entamethylenethiuram
tetrasulfide, dipentamethylenethiuram hexasulfide, tetrabutylthiuram
disulfide, and pentamethylenethiuram tetrasulfide can be used. As the
thiourea-based vulcanization accelerator, thiourea compounds such as
thiacarbamide, diethylthiourea, dibutylthiourea, trimethylthiourea, and
diorthotolylthiourea can be used. As the guanidine-based vulcanization
accelerator, guanidine-based compounds such as diphenylguanidine,
diorthotolylguanidine, triphenylguanidine, orthotolylbiguanide, and
diphenylguanidine phthalate can be used. As the dithiocarbamic acid-based
vulcanization accelerator, dithiocarbamic acid-based compounds such as
zinc ethylphenyldithiocarbamate, zinc butylphenyldithiocarbamate, sodium
dimethyldithiocarbamate, zinc dimethyldithiocarbamate, zinc
diethyldithiocarbamate, zinc dibutyldithiocarbamate, zinc
diamyldithiocarbamate, zinc dipropyldithiocarbamate, a complex salt of
zinc pentamethylenedithiocarbamate and piperidine, zinc hexadecyl (or
octadecyl)isopropyldithiocarbamate, zinc dibenzyldithiocarbamate, sodium
diethyldithiocarbamate, pentamethylenedithiocarbamic acid piperidine,
selenium dimethyldithiocarbamate, tellurium diethyldithiocarbamate, and
cadmium diamyldithiocarbamate can be used. As the aldehyde-amine-based or
aldehyde-ammonia-based vulcanization accelerator, aldehyde-amine-based or
aldehyde-ammonia-based compounds such as an acetoaldehyde-aniline
reaction product, a butylaldehyde-aniline condensate,
hexamethylenetetramine, and an acetoaldehyde-ammonia reaction product can
be used. As the imidazoline-based vulcanization accelerator,
imidazoline-based compounds such as 2-mercaptoimidazoline can be used. As
the xanthate-based vulcanization accelerator, xanthate-based compound
such as zinc dibutylxanthogenate can be used. These vulcanization
accelerators may be used alone, or may be used by combining two or more
[0072] As the vulcanization accelerator auxiliary agent, for example, zinc
oxide, and stearic acid can be used.
[0073] As the aging preventing agent, amine-based agent, phenol-based
agent, imidazole-based agent, and a carbamic acid metal salt can be used
by appropriate selection.
[0074] The rubber composition of the present invention may contain a
stearic acid metal salt. Examples of the stearic acid metal salt include
such as magnesium stearate, magnesium 12-hydroxystearate, calcium
stearate, calcium 12-hydroxystearate, barium stearate, barium
12-hydroxystearate, zinc stearate, and zinc 12-hydroxystearate. Among the
stearic acid metal salt, from a viewpoint of the effect of improving heat
resistance, and compatibility with the epoxidized natural rubber, a
stearic acid alkaline earth metal salt is preferable, and calcium
stearate, calcium 12-hydroxystearate, barium stearate, and barium
12-hydroxystearate are more preferable.
[0075] Examples of the oil include such as a process oil, a vegetable oil,
and a mixture thereof. Examples of the process oil include such as a
paraffin-based process oil, a naphthene-based process oil, and an
aromatic-based process oil. Examples of the vegetable oil include such as
a castor oil, a cotton seed oil, a linseed oil, a rapeseed oil, a soybean
oil, a palm oil, a coconut oil, a peanut oil, a pine oil, a pine tar, a
tall oil, a corn oil, a rice oil, a safflower oil, a sesame oil, an olive
oil, a sunflower oil, a palm kernel oil, a camellia oil, a jojoba oil, a
macadamia nut oil, a safflower oil, and a paulownia oil.
<Physical Property>
[0076] The rubber composition of the present invention has enabled to
(rigidity, hardness, and mechanical strength etc. when used in the clinch
rubber, rolling resistance property, and operation stability etc. when
used in the base tread, gripping performance, durability including
abrasion resistance, rolling resistance property, and heat generation
property etc. when used in the tread, and a hardness, breakage property
etc. when used in the bead apex), and improvement in processibility while
a use amount of a raw material derived from a petroleum source is
reduced. Here, improved "processibility" refers to that a stickiness
index calculated by the following calculation equation from a tacking
force of an unvulcanized rubber composition measured (details such as
measurement condition will be described later) using a PICMATAC tester
(manufactured by Toyo Seiki Seisaku-sho, Ltd.) is 105 or more (further
preferably 110 or more), when the rubber composition of the present
invention is used in the carcass ply or the bead apex.
Stickiness Index=(tacking force of rubber composition of the present
invention/tacking force of standard compounding rubber
composition)×100
[0077] In addition, when the rubber composition of the present invention
is used in the clinch rubber, the base tread or the tread, improved
"processibility" refers to that the aforementioned stickiness index is
105 or more (further preferably 110 or more) and, additionally, a Mooney
viscosity index calculated by the following calculation equation from a
Mooney viscosity of an unvulcanized rubber composition measured (details
such as measurement condition will be described later) using a Mooney
viscometer (manufactured by Shimadzu Corporation) according to the
provision of JIS K6300 is 105 or more (further 110 or more).
Mooney viscosity index=(Mooney viscosity of standard compounding rubber
composition)/(Mooney viscosity of rubber composition of the present
invention)×100
[0078] The standard compounding rubber composition in each of the
calculating equation refers to a rubber composition which is compounded
into the same composition as the rubber composition of the present
invention except that at least any one of the terpene-based resin and the
rosin-based resin is not contained.
[0079] The present invention also provides a pneumatic tire using the
aforementioned rubber composition of the present invention. Here, FIG. 1
is a schematic cross-sectional view showing one example of the pneumatic
tire of the present invention. The pneumatic tire 1 includes a tread part
2 provided with a cap tread part 2a and a base tread part 2b, a pair of
side wall parts 3 extending inwardly in a tire radial direction from both
ends of tread part 2, and a bead part 4 situated at an inner end of each
side wall part 3. In addition, a carcass 6 is bridged between bead parts
4, 4 and, at the same time, a belt layer 7 having the hoop effect to
reinforce tread part 2 is disposed on an outer side of this carcass 6 and
in tread part 2.
[0080] Above mentioned carcass 6 is formed of one or more carcass plies 6a
in which a carcass cord is arranging at an angle of, for example, 70 to
90° relative to a tire equator CO, and this carcass ply 6a is
locked by turning up from an inner side to an outer side in a tire axial
direction around a bead core 5 of bead part 4 via from the aforementioned
tread part 2 to side wall part 3.
[0081] Above mentioned belt layer 7 is formed of two or more belt plies 7a
in which a belt cord is arranged at an angle of, for example, 40°
or less relative to a tire equator CO, and each belt cord is piled up in
different directions so as to cross between plies. If necessary, a band
layer (not shown) for preventing lifting of both ends of belt layer 7 may
be provided at least outside belt layer 7 and, thereupon, the band layer
is formed of a continuous ply in which an organic fiber cord having a low
modulus is spirally wound approximately parallel with the tire equator
[0082] In addition, in bead part 4, a bead apex rubber 8 extending
outwardly in a radial direction from bead core 5 is disposed and, at the
same time, on an inner side of carcass 6, an inner liner rubber 9 forming
a tire inner cavity surface is provided adjacent, and an outer side of
carcass 6 is protected with a clinch rubber 4G and a side wall rubber 3G.
The rubber composition of the present invention can be used in at least
any one selected from clinch rubber 4G, base tread part 2b, cap tread
part 2a, carcass ply 6a and bead apex rubber 8.
[0083] FIG. 1 exemplifies the pneumatic tire for a passenger automobile,
but the present invention is not limited to this, and provides a
pneumatic tire being used in application of various vehicles such as a
passenger automobile, a truck, a bus, and a heavy vehicle.
[0084] The pneumatic tire of the present invention is produced by the
previously known method using the rubber composition of the present
invention. That is, a rubber composition containing the aforementioned
essential components, and other compounding ingredients which are
compounded optionally is kneaded, extrusion-processed the resin
composition in conformity with a shape of at least any one selected from
a clinch, a base tread part, a tread rubber, a carcass ply and a bead
apex of a tire at at a stage of unvulcanization, and molding together
with other members of the tire on a tire molding machine by a
conventional method, thereby, an unvulcanized tire is formed. By heating
and pressing this unvulcanized tire in a vulcanizing machine, the tire of
the present invention can be obtained.
[0085] In addition, when the rubber composition of the present invention
is used in the carcass ply, after the composition in the aforementioned
unvulcanized state is extrusion-processed into a shape of the carcass
ply, this is applied on an upper surface and a lower surface of a cord
for a tire to be embedded to make the carcass ply, and together with
other members of the tire, the carcass ply is molded on a tire molding
machine by a conventional method. In this case, the carcass ply is not
particularly limited as far as it complies the aforementioned rubber
composition for the carcass ply of the present invention, and an
appropriate material which has previously been known as a cord for a tire
(e.g. rayon fiber, purified cellulose fiber etc.) can be also used.
[0086] Since the pneumatic tire of the present invention uses a rubber
composition in which a content ratio of components derived from a
petroleum source is further reduced, source saving and environmental
protection are sufficiently considered and, at the same time, both of
maintenance of better physical property desired depending on each
application, and improvement in processibility are realized, it is an
"ecological tire" which is friendly to the earth environment and, at the
same time, has improved processibility, and has desired property such as
better durability and operation stability in a clinch rubber, a base
tread or a bead apex, desired property such as gripping performance,
durability including abrasion resistance, rolling resistance property,
and heat generation property in a tread, and desired property as a
carcass ply.
[0087] The present invention will be described in more detail below by way
of Examples and Comparative Examples, but the present invention is not
Rubber Composition for Clinch Rubber
[0088] According to compounding and formulation shown in Table 1, and
using a 1.7 L Banbury mixer manufactured by KOBE STEEL, LTD., compounding
components except for sulfur and a vulcanization accelerator were charged
to a charging rate of 58%, and kneaded at a rotation number of 80 rpm for
3 minutes until a temperature reached 140° C. Then, after sulfur
and a vulcanization accelerator were added to the resulting kneaded
product at compounding amounts shown in Table 1, the mixture was kneaded
at 80° C. for 5 minutes using an open roll to obtain unvulcanized
rubber compositions related to Example 1 and Comparative Examples 1 and
Compounding Natural rubber 100 100 80 100 100
amount Epoxidized natural -- -- 20 -- --
(part by mass) rubber
Carbon black 5 5 5 5 5
Silica 60 60 60 60 60
Silane Coupling 4.8 4.8 4.8 4.8 4.8
Oil 1.2 1.2 1.2 1.2 1.2
Resin (1) -- -- -- 1 3
Resin (2) 1 3 3 -- --
Age resister 2.4 2.4 2.4 2.4 2.4
Vulcanization 2.0 2.0 2.0 2.0 2.0
Rubber Stickiness 110 115 110 100 110
processibility Reduction in 110 115 110 100 100
[0089] Details of various compounding components used in Examples 1 to 3,
and Comparative Examples 1 and 2 are as follows.
(1) Natural rubber (NR): SIR (manufactured in Indonesia) (2) Epoxidized
natural rubber (ENR): ENR25 (manufactured by Malaysian Rubber Board)
(epoxidization rate: 25%) (3) Carbon black: Show Black N220 (manufactured
by Cabot Japan K.K.) (4) Silica: Ultrasil VN3 (manufactured by Evonik
Degussa Japan Co., Ltd.) (BET specific surface area: 210 m2/g) (5)
Silane coupling agent: Si266 (manufactured by Evonik Degussa Japan Co.,
Ltd.) (6) Oil: NH60 (manufactured by Idemitsu Kosan Co., Ltd) (7) Resin
(1): Marcalets T100AS (manufactured by Maruzen Petrochemical Co., Ltd)
(8) Resin (2): Terpene resin PX300N (manufactured by YASUHARA CHEMICAL
CO., LTD.) (9) Wax: Sunnoc Wax (manufactured by OUCHI SHINKO CHEMICAL
INDUSTRIAL CO., LTD.) (10) Age resister: Nocrac 6C (manufactured by OUCHI
SHINKO CHEMICAL INDUSTRIAL CO., LTD.)
(N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine)) (11) Stearic acid:
Paulownia (manufactured by Nippon Oil & Fat Co., Ltd.) (12) Zinc oxide:
Zinc white (manufactured by MITSUI MINING & SMELTING CO., LTD.) (13)
Sulfur: powdery sulfur (manufactured by Tsurumi Chemical Co., Ltd.) (14)
Vulcanization accelerator: Nocceler NS (manufactured by OUCHI SHINKO
[0090] Regarding unvulcanized rubber compositions obtained in Examples 1
to 3, and Comparative Examples 1 and 2, the following test was performed.
Table 1 also shows the test results.
[0091] Using a PICMATAC tester (manufactured by Toyo Seiki Seisaku-sho,
Ltd.), a tacking force [N] of an unvulcanized rubber composition at a
temperature of 23° C. and a humidity of 55% was measured under the
condition of a rising speed of 30 mm/min and a measuring time of 2.5
seconds. Further, letting a stickiness index of the rubber composition of
Comparative Example 1 as a standard compounding rubber composition to be
100, a tacking force was expressed by an index by the following
calculating equation. A greater tackiness index indicates that a tacking
force is greater, and more excellent.
Stickiness index=(tacking force of each Example and each Comparative
Example/tacking force of standard compounding)×100
(Mooney Viscosity Index)
[0092] A Mooney viscosity of an unvulcanized rubber composition was
measured at 130° C. according to JIS K6300 and, letting the rubber
composition of Comparative Example 1 as a standard compounding rubber
composition to be 100, a Mooney viscosity was expressed by an index by
the following calculating equation. A greater Mooney viscosity index
indicates that a viscosity is lower, and processing is easier.
[0093] According to compounding formulation shown in table 2, and using a
1.7 L Banbury mixer manufactured by KOBE STEEL, LTD, compounding
so that a charging rate became 58%, and the mixture was kneaded for 3
minutes at a rotation number of 80 rpm until a temperature reached at
160° C. Then, to the resulting kneaded product were added sulfur
and a vulcanization accelerator at compounding amounts shown in Table 2,
the mixture was kneaded at 80° C. for 5 minutes using an open roll
to obtain unvulcanized rubber compositions of compounding related to
Examples 4 to 6, and Comparative Examples 3 and 4.
Silica 50 50 50 50 50
Silane Coupling 4 4 4 4 4
Oil 4 2 2 4 2
Age resister 2 2 2 2 2
Rolling resistance property 100 90 90 100 90
Operation stability 100 110 120 100 110
[0094] Details of various compounding components used in Examples 4 to 6,
and Comparative Examples 3 and 4 are as follows.
[0095] Regarding unvulacanized rubber compositions obtained in Examples 4
to 6, and Comparative Examples 3 and 4, the following test was performed.
[0096] According to the same manner as described above except that a
stickiness index of the rubber composition of Comparative Example 3 as a
standard compounding rubber composition was 100, a tacking force was
expressed by an index.
[0097] According to the same manner as described above except that the
rubber composition of Comparative Example 3 as a standard compounding
rubber composition was 100, a Mooney viscosity was expressed by an index.
(Rolling Resistance Property)
[0098] Using rubber compositions obtained in Examples 4 to 6, and
Comparative Examples 3 and 4, test pieces having a size of 4.0 mm
(width)×30 mm (length)×mm (thickness) were prepared, a loss
tangent (tanδ) was measured under the condition of a temperature of
70° C., an initial strain of 10%, and a dynamic strain of 2% using
a viscoelasticity spectrometer (manufactured by IWAMOTO Quartz GlassLab
Co., Ltd.) and, letting the rubber composition of Comparative Example 3
as a standard compounding rubber composition to be 100, rolling
resistance property was expressed by an index by the following
calculating equation. A greater rolling resistance property index
indicates that rolling resistance property is higher.
Rolling resistance property index=(tan δof Comparative Example
3)/(tan δof each compounding)×100
(Operation Stability)
[0099] Using rubber compositions obtained in Examples 4 to 6, and
(width)×30 mm (length)×mm (thickness) were prepared, a
complex modulus (E*) was measured under the condition of a temperature of
as a standard compounding rubber composition to be 100, operation
stability was expressed by an index by the following calculating
equation. A greater operation stability index indicates that operation
Operation stability index=(E*of each compounding)/(E*of Comparative
Example 3)×100
Examples 7 and 8, Comparative Examples 5 and 6
Rubbers Composition for Tread
[0100] According to compounding formulation shown in Table 3, and using a
and a vulcanization accelerator at compounding amounts shown in Table 3,
and the mixture was kneaded at 80° C. for 5 minutes using an open
roll to obtain unvulcanized rubber compositions of compounding related to
Examples 7 and 8, and Comparative Examples 5 and 6.
Exam- Exam- ative ative
ple 7 ple 8 Example 5 Example 6
Com- Natural rubber 30 30 30 30
pounding Epoxidized 70 70 70 70
amount natural rubber
(part by Carbon black 5 5 5 5
mass) Silica 75 75 75 75
Silane 6 6 6 6
Oil 12 14 14 12
Resin (1) -- -- 1 3
Resin (2) 1 3 -- --
Wax 1.5 1.5 1.5 1.5
Age resister 2 2 2 2
Vulcanization 2.0 2.0 2.0 2.0
Rubber Stickiness 110 115 100 110
processibility Reduction 110 115 100 100
Gripping Dry 100 110 100 110
performance Wet 100 100 100 100
Abrasion resistance 100 98 100 98
Rolling resistance property 100 95 100 95
Heat generation property 100 95 100 95
[0101] Details of various compounding components used in Examples 7 and 8,
and Comparative Examples 5 and 6 are as follows.
[0102] Regarding unvulcanized rubber compositions obtained in Examples 7
and 8, and Comparative Examples 5 and 6, the following test was
performed. Table 3 also shows the test results.
[0103] According to the same manner as described above except that a
stickiness index of the rubber composition of Comparative Example 5 as a
[0104] According to the same manner as described above except that the
rubber composition of Comparative Example 5 as a standard compounding
[0105] Using rubber compositions obtained in Examples 7 and 8, and
Comparative Examples 5 and 6, test pieces having a size of 4.0 mm
(width)×30 mm (length)×2.0 mm (sickness) were prepared, a
loss tangent (tan δ) was measured under the condition of a
temperature of 30° C., an initial strain of 10%, and a dynamic
strain of 2% regarding dry gripping performance, or under the condition
of a temperature of 0° C., an initial strain 10%, and a dynamic
strain of 2% regarding wet gripping performance using a viscoelasticity
spectrometer (manufactured by IWAMOTO Quartz GlassLab Co., Ltd.) and,
letting the rubber composition of Comparative Example 5 as a standard
compounding rubber composition to be 100, gripping performance was
expressed by an index by the following calculating equation. A greater
gripping performance index indicates that gripping performance is better.
Gripping performance index=(tan δof each compounding)/(tan
δof Comparative Example 5)×100
[0106] Using rubber compositions obtained in Examples 7 and 8, and
Comparative Examples 5 and 6, text pieces having a size of 49 mm (outer
diameter)×5 mm (stickiness) were prepared, an abrasion mass was
measured under the condition of a temperature of 23° C., a load of
30N, and a slippage rate of 40% using a Lambourn abrasion testing machine
(manufactured by Ueshima Seisakusho Co., Ltd.) according to the provision
of JIS K-6246 and, letting the rubber composition of Comparative Example
5 as a standard compounding rubber composition to be 100, abrasion
resistance was expressed by an index by the following calculating
equation. A greater abrasion resistance index indicates that abrasion
resistance is better.
Abrasion resistance index=(Abrasion mass of Comparative Example
5)/(abrasion mass of each compounding)×100
[0107] Using rubber compositions obtained in Examples 7 and 8, and
(width)×30 mm (length)×mm (stickiness) are prepared, a loss
tangent (tan δ) was measured under the condition of a temperature
of 70° C., an initial strain of 10%, and a dynamic strain of 2%
using a viscoelasticity spectrometer (manufactured by IWAMOTO Quartz
GlassLab Co., Ltd.) and, letting the rubber composition of Comparative
Example 5 as a standard compounding rubber composition to be 100, rolling
5)/(tan δof each compounding)×100
(Heat Generation Property)
[0108] Using rubber compositions obtained in Examples 7 and 8, and
(width)×30 mm (length)×mm (stickiness) were prepared, a loss
compliance was measured under the conditions of a temperature of
100° C., and an initial strain of 10%, and a dynamic strain of 2%
Example 5 as a standard compounding rubber composition to be 100, heat
generation property was expressed by an index by the following
calculating equation. A greater heat generation property index indicates
that heat generation property is better.
Heat generation property index=(loss compliance of Comparative Example
5)/(loss compliance of each compounding)×100
Example 9, Comparative Examples 7 and 8
Rubber Composition for Carcass Ply
[0109] According to compounding formulation shown in Table 4, and using a
140° C. Then, to the resulting kneaded product were added sulfur
and a vulcanization accelerator at compounding amounts shown in Table 4,
Example 9, and Comparative Examples 7 and 8.
Exam- Comparative Comparative
ple 9 Example 7 Example 8
Com- Natural rubber 70 70 70
pounding Epoxidized 30 30 30
(part by Carbon black 15 15 15
mass) Silica 50 50 50
Silane 6 6 6
Oil 15 15 15
Resin (1) -- 3 --
Resin (2) 3 -- --
Vulcanization 2.0 2.0 2.0
Rubber Stickiness 110 100 65
[0110] Details of various compounding components used in Example 9, and
Comparative Examples 7 and 8 are as follows.
1) Natural rubber (NR): RSS#3 (manufactured by Teck Bee Hung) (2)
Epoxidized natural rubber (ENR): ENR25 (manufactured by Kumpulan Guthrie
Berhad) (epoxidization rate: 25%) (3) Carbon black: Show Black N220
(manufactured by Cabot Japan K.K.) (4) Silica: Ultrasil VN3 (manufactured
by Evonik Degussa Japan Co., Ltd.) (5) Silane coupling agent: Si69
(manufactured by Evonik Degussa Japan Co., Ltd.) (6) Oil: NH60
(manufactured by Idemitsu Kosan Co., Ltd) (7) Resin (1): Petroleum-based
resin (Marcalets T100AS (manufactured by Maruzen Petrochemical Co., Ltd))
(8) Resin (2): Terpene resin (PX300N (manufactured by YASUHARA CHEMICAL
CO., LTD.)) (9) Wax: Sunnoc Wax (manufactured by OUCHI SHINKO CHEMICAL
INDUSTRIAL CO., LTD.) (10) Age resister: Santflex 6PPD (manufactured by
Flexsys) (11) Stearic acid: Paulownia (manufactured by Nippon Oil & Fat
Co., Ltd.) (12) Zinc oxide: Zinc white (manufactured by MITSUI MINING &
SMELTING CO., LTD.) (13) Sulfur: powdery sulfur (manufactured by Tsurumi
Chemical Co., Ltd.) (14) Vulcanization accelerator: Nocceler NS
(manufactured by OUCHI SHINKO CHEMICAL INDUSTRIAL CO., LTD.)
[0111] Regarding uvulcanized rubber compositions obtained in Example 9,
and Comparative Examples 7 and 8, the following test was performed. Table
4 also shows the test results.
[0112] A tacking force [N] of the unvulcanized rubber composition was
measured under the condition of a measuring temperature of 20° C.,
a load of 4.9N, a standing time of 10 seconds, and a peeling rate of 30
mm/min using a PICMATAC tester (manufactured by Toyo Seiki Seisaku-sho,
Ltd.) according to the provision of JIS-T 9233. Further, as a standard
compounding rubber composition, letting a stickiness index of the rubber
composition of Comparative Example 7 to be 100, a tacking force was
expressed by an index by the following calculation and equation. A
greater stickiness index indicates that a tacking force is greater, being
Example 10, Comparative Examples 9 and 10
Rubber Composition for Bead Apex
[0113] According to compounding formulation shown in Table 5, and using a
and a vulcanization accelerator at compounding amounts shown in Table 5,
roll to obtain unvulcanized rubber compositions of compounding relative
to Example 10, and Comparative Examples 9 and 10.
ple 10 Example 9 Example 10
Com- Natural rubber 100 100 100
pounding Peptizing agent 0.5 0.5 0.5
amount Resin (1) -- 3 --
(part by Resin (2) 3 -- --
mass) Carbon black 5 5 5
Silica 70 70 70
Silane 5.6 5.6 5.6
Zinc oxide 4 4 4
Sulfur 2.4 2.4 2.4
Vulcanization 2.8 2.8 2.8
Rubber Stickiness 108 100 15
[0114] Details of various compounding components used in Example 10, and
Comparative Examples 9 and 10 are as follows.
(1) Natural rubber (NR): RSS#3 (manufactured by Teck Bee Hung) (2)
Peptizing agent: Noctizer SD (manufactured by OUCHI SHINKO CHEMICAL
INDUSTRIAL CO., LTD.) (3) Resin (1): Petroleum-based resin (Marcalets
T100AS (manufactured by Maruzen Petrochemical Co., Ltd)) (4) Resin (2);
Terpene-besed resin (PX300N (manufactured by YASUHARA CHEMICAL CO.,
LTD.)) (5) Carbon black: (Show Black N220 (manufactured by Cabot Japan
K.K.) (6) Silica: Ultrasil VN3 (manufactured by Evonik Degussa Japan Co.,
Ltd) (7) Silane coupling agent: Si69 (manufactured by Evonik Degussa
Japan Co., Ltd.) (8) Age resister: Nocrac 6C (manufactured by OUCHI
(N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine)) (9) Stearic acid:
Paulomania (manufactured by Nippon Oil & Fat Co., Ltd.) (10) Zinc oxide:
Zinc white (manufactured by Mitsui MITSUI MINING & SMELTING CO., LTD.)
(11) Sulfur: powdery sulfur (manufactured by Tsurumi Chemical Co., Ltd.)
(12) Vulcanization accelerator: Nocceler NS (manufactured by OUCHI SHINKO
[0115] Regarding unvulcanized rubber compositions obtained in Example 10,
and Comparative Examples 9 and 10, the following test was performed.
Table 5 also shows the test results.
[0116] A tacking force [N] of the unvulcanized rubber composition was
composition of Comparative Example 9 to be 100, a tacking force was
stickiness index indicates that a tacking force is greater, being
[0117] Although the present invention has been described and illustrated
Patent applications by Shuichi Sakamoto, Kobe-Shi JP
Patent applications in class Apex or filler strip Patent applications in all subclasses Apex or filler strip User Contributions:
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