JPH11279331A - Rubber composition and pneumatic tire using it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the thermal aging property, thermal hardening property and breakdown property, by making the composition contain a raw material rubber, a specific polyoxyethylenealkylamine deriv. and a dithiophosphoric acid compd. type vulcanization accelerating agent. SOLUTION: One hundred pts.wt. of at least one type of raw material rubber selected from the group consisting of a natural rubber and a diene type synthetic rubber is blended with 0.1-10.0 pts.wt., pref. 0.5-5.0 pts.wt., of at least one type of polyoxyethylenealkylamine deriv. selected from the group consisting of the compds. of formulae I, II (wherein R is 1-20C alkyl; x is 0-5; and y is 1-5), etc., a metallic salt of dithiophosphoric acid having formula III (wherein R<1-2> are each 1-8C straight-chain, branched-chain or cyclic alkyl, or 6-1 0 C aryl; M' is Zn, Sb, Fe or Cu; and n is a valency of the bonded metal), 0.1-10.0 pts.wt., pref. 0.2-5.0 pts.wt., of at least one type of dithiophosphoric acid compd. type vulcanization accelerating agent selected from the group consisting of an o,o'- dialkyldithiophosphoric acid disulfide and an o,o'-dialkyldithiophosphoric acid tetrasulfide.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rubber composition and a pneumatic tire using the same.
In particular, the present invention relates to a rubber composition used for a tire tread and the like, which is excellent in heat resistance and breaking properties, and a pneumatic tire using the same.

[0002]

2. Description of the Related Art In recent years, as the performance and speed of automobiles have been improved, tires, particularly tread members, have been required to have higher heat aging resistance and fracture characteristics than ever before.

[0003] In response to this demand, various compounding agents for the tread rubber composition have been studied. Focusing on the metal dithiophosphate in connection with the present invention in this compounding agent, regarding rubber compositions using the metal dithiophosphate, U.S. Pat. Nos. 1,288,616 and 3,426, 003
No. (Monsanto, USA, currently FLEXSYS) describes that a rubber composition using zinc dithiophosphate has an effect of preventing reversion, and JP-A-54-85243 discloses that a metal salt of dithiophosphate is sulfur-free cross-linked. It is said to be effective as a component.

[0004] Japanese Patent Publication No. 6-29342 discloses a carbon blend of a combination of a metal salt of dithiophosphate and bismaleimide and sulfenamide, which has scorch stability, reversion resistance, heat deterioration resistance, and flex crack deterioration resistance. Rubber compositions having excellent properties have been proposed.

In Japanese Patent Application Laid-Open No. 58-87138,
It is disclosed that a rubber composition containing a specific vulcanization accelerator and a specific antioxidant improves heat-curing resistance and improves the appearance at the end of tire running. Also, JP-A-56-13
No. 9542 discloses that a rubber composition using a specific vulcanization accelerator improves sintering (scorchability) in rubber kneading.

[0006]

DISCLOSURE OF THE INVENTION The present invention has been made in view of the above facts, and an object of the present invention is to further improve the heat aging resistance, especially the property of suppressing rubber curing after heat aging, that is, heat resistance curing. An object of the present invention is to provide a rubber composition having improved properties and breaking characteristics and a pneumatic tire using the same.

[0007]

Means for Solving the Problems The present inventors have focused on polymers and various compounding agents to be compounded in tread rubber, and as a result of diligent studies, have found that the following means can solve the problems. It was completed.

That is, (1) The rubber composition of the present invention comprises:
In the tread portion of the pneumatic tire, the rubber of the tread portion is a raw rubber 10 made of at least one rubber selected from the group consisting of natural rubber and diene-based synthetic rubber.
The following general formulas (A), (B) and
0.1 to 10.0 parts by weight of at least one of the polyoxyethylene alkylamine derivatives represented by (C), (D), (E) and (F), and represented by the following general formula (I) At least one dithiophosphate compound-based vulcanization accelerator selected from the group consisting of a metal dithiophosphate, O, O'-dialkyldithiophosphate disulfide and O, O'-dialkyldithiophosphate tetrasulfide, It is characterized by containing 0.1 to 10.0 parts by weight with respect to 100 parts by weight.

[0009]

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(In the formula, R independently represents an alkyl group having 1 to 20 carbon atoms, x represents an integer of 0 to 5, and y and z represent 1 to 5 independently of each of the formulas (A) to (F).) Represents an integer of 5 and n is 1 to
Represents an integer of 10. )

[0011]

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(Wherein R ¹ and R ² are each independently
Represents an alkyl group having 1 to 8 carbon atoms or an aryl group having 6 to 10 carbon atoms. This alkyl group may be linear, branched or cyclic. M ¹ represents a Zn atom, an Sb atom, an Fe atom or a Cu atom, and n represents the number of valences of the metal to be bonded. (2) The polyoxyethylene alkylamine derivative represented by the general formula described in the above item (1) is preferably represented by the formula (A) or (B).

(3) The polyoxyethylene alkylamine derivative represented by the general formula described in the above item (1) is represented by the formula (A), and it is preferable that x = 1.

(4) The general formula described in the above (1).
The metal dithiophosphate represented by the formula (I) is represented by the following general formula (II)
The dithiophosphate compound-based vulcanization accelerator represented by

[0015]

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(Wherein, M ² represents a Zn atom or an Sb atom, and n represents the number of valences of the metal to be bonded.) (5) The rubber composition of the present invention is used in a tread portion of a pneumatic tire. At least one rubber selected from the group consisting of natural rubber and diene-based synthetic rubber;
The general formulas (A), (B), (C), and (C) according to claim 1 with respect to 100 parts by weight of a raw rubber composed of a kind of rubber.
At least one of the polyoxyethylene alkylamine derivatives represented by (D), (E) or (F) is 0.1 to 1;
0.0 parts by weight, and the following general formulas (III), (IV),
At least one benzothiazole compound-based vulcanization accelerator selected from the group consisting of the compounds represented by (V) and (VI) is used in an amount of 0.1 to 1 based on 100 parts by weight of the raw rubber.
It is characterized by containing 0.0 parts by weight.

[0017]

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[0018]

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[0019]

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[0020]

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(Wherein R ³ and R ⁴ are each independently
Hydrogen atom, alkyl group having 1 to 8 carbon atoms or 6 to 1 carbon atoms
Represents an aryl group of 0. However, the case where R ³ and R ⁴ are a hydrogen atom at the same time is excluded. R ⁵ represents an alkyl group, an alkenyl group or a cycloalkyl group having 1 to 8 carbon atoms, R ⁶
Represents a hydrogen atom or -N amino group represented by (R ⁷⁾ R ^8, an alkyl group or a cyclohexyl group of R ⁷ and R ⁸ are each independently a hydrogen atom or a C2-4. However, the case where R ⁷ and R ⁸ are a hydrogen atom at the same time is excluded.
R ⁹ and R ¹⁰ each independently represent an alkyl group, alkenyl group or cycloalkyl group having 1 to 8 carbon atoms. X is Z
represents n atom, an amino group represented by Cu atom or> N-R ^13, R ¹³ represents an alkyl group or a cyclohexyl group having 2 to 4 carbon atoms. R ¹¹ and R ¹² have the same meaning as R ⁹ . (6) The polyoxyethylene alkylamine derivative represented by the general formula described in the above (5) is preferably represented by the formula (A) or (B).

(7) The polyoxyethylene alkylamine derivative represented by the general formula described in the above item (5) is represented by the formula (A), and it is preferable that x = 1.

(8) The general formula (III) described in the above item (5)
R ^{3 of} a benzothiazole compound-based vulcanization accelerator represented by
And R ⁴ are preferably each independently a hydrogen atom, a methyl group, an ethyl group or a phenyl group (except when R ³ and R ⁴ are simultaneously a hydrogen atom).

(9) The formula (III) described in the above item (5)
Are bis- (4-methylbenzothiazolyl-2) disulfide, bis- (5-methylbenzothiazolyl-2) disulfide, mercapto-4- It is preferably at least one selected from the group consisting of methylbenzothiazole and mercapto-5-methylbenzothiazole.

(10) The formula (I) described in the above item (5)
The position of the alkoxy group of the benzothiazole compound-based vulcanization accelerator represented by (V), (V) or (VI) in the aromatic monocycle is preferably at the 4- or 6-position.

(11) The formula (I) described in the above item (5)
The alkoxy group of the benzothiazole compound-based vulcanization accelerator represented by (V), (V) or (VI) is preferably a group selected from the group consisting of a methoxy group, an ethoxy group and a butoxy group.

(12) A pneumatic tire according to the present invention is characterized in that the rubber composition according to claim 1 or 5 is applied to a tire tread.

As described above, the present invention is particularly characterized in that a specific polyoxyethylene alkylamine derivative is used in combination with a specific vulcanization accelerator.

[0029]

BEST MODE FOR CARRYING OUT THE INVENTION The rubber component used in the present invention is at least one selected from the group consisting of natural rubber and diene-based synthetic rubber. That is, from natural rubber (NR) and many diene-based synthetic rubbers, they may be used alone or in a blend of two or more of them. Examples of the diene-based synthetic rubber include synthetic polyisoprene rubber (IR), polybutadiene rubber (BR), styrene butadiene rubber (SBR), and butyl rubber (IIR).
And the like.

In the present invention, among these rubber components, for example, SBR alone, SBR / NR blend, SBR / NR
NR / BR blends and the like are preferably used from the viewpoint of effects.

The polyoxyethylene alkylamine derivative used in the present invention, when used together with a dithiophosphoric acid compound-based vulcanization accelerator and / or a benzothiazole compound-based vulcanization accelerator, greatly contributes to the effect of suppressing the curing after heat aging. It is an important factor in this respect. As the polyoxyethylene alkylamine derivative, the above-mentioned general formulas (A), (B),
At least one selected from the group consisting of (C), (D), (E) and (F) is used.

Formulas (A), (B), (C), (D),
Specific examples of (E) and (F) include (A) Duspar 125B, 125BN (trade name, manufactured by Miyoshi Oil & Fats Co., Ltd.), and (B) Miyocol 324 (trade name, manufactured by Miyoshi Oil & Fats Co., Ltd.). C) as Nimeen L-201 (trade name, manufactured by NOF Corporation) and (D) as Nimeen L
Such as Nissan Nymein DT-203 (trade name, manufactured by Nippon Yushi) as (E) and TAMDS-15 (trade name, Nikko Chemicals) as (F). Other UNIOX M-2000
(Trade name, manufactured by NOF Corporation). Above all, the formula (A)
Or (B) is preferable. In addition, Expression (A), and x = 1
Is more preferable.

The amount of the polyoxyethylene alkylamine derivative is 0.1 to 1 based on 100 parts by weight of the raw rubber.
0.0 parts by weight, preferably 0.5 to 5.0 parts by weight. If the compounding amount exceeds 10.0, the effect of suppressing the curing is observed, but the scorch is shortened and the elastic modulus of the vulcanized rubber is lowered, which is not preferable.

The dithiophosphate compound-based vulcanization accelerator used in one embodiment of the present invention is a metal dithiophosphate represented by the above general formula (I), O, O'-dialkyldithiophosphate disulfide and O, O'- It is at least one selected from the group consisting of dialkyldithiophosphate tetrasulfide.

R ¹ and R ² of the metal dithiophosphate represented by the general formula (I) each independently have 1 to 8 carbon atoms.
An alkyl group or an aryl group having 6 to 10 carbon atoms,
This alkyl group may be linear, branched or cyclic. M ¹ is a Zn atom, Sb atom, Fe atom or Cu atom, and n is the number of valences of the metal to be bonded. Among them, R ¹ and R ² are preferably an alkyl group having 3 to 4 carbon atoms. Metal dithiophosphates having an alkyl group having 2 or less carbon atoms tend to have low solubility in rubber, and if the number of carbon atoms is 5 or more, the effect cannot be further improved. Is not always effective. As the metal, a Zn atom is preferable.
That is, a zinc dithiophosphate represented by the formula (II) is preferable. The amount of the zinc salt is preferably from 0.1 to 5.0 parts by weight, more preferably from 0.2 to 3.0 parts by weight.

That is, these metal dithiophosphates include, for example, zinc O, O'-dipropyldithiophosphate, zinc O, O'-diisopropyldithiophosphate,
O'-di-n-butyl zinc dithiophosphate, O, O'-di-sec-butyl zinc dithiophosphate, O, O'-di-t
-Butyldithiophosphate, zinc O, O'-diphenyldithiophosphate, zinc O, O'-dicyclohexyldithiophosphate, antimony O, O'-dipropyldithiophosphate, antimony O, O'-diisopropyldithiophosphate, O, O Antimony '-di-n-butyldithiophosphate, antimony O, O'-di-sec-butyldithiophosphate, antimony O, O'-di-t-butyldithiophosphate, antimony O, O'-diphenyldithiophosphate
O, O'-dicyclohexylantimony antiphosphate; and the like. Among them, zinc O, O'-diisopropyldithiophosphate, zinc O, O'-di-n-butyldithiophosphate, antimony O, O'-diisopropyldithiophosphate, Antimony O, O'-di-n-butyldithiophosphate is preferred. These vulcanization accelerators can be used alone or in a mixture of two or more.

Examples of the O, O'-dialkyldithiophosphate disulfide or O, O'-dialkyldithiophosphate tetrasulfide include, for example, O, O'-dibutyldithiophosphate disulfide, O, O'-diisopropyldithiophosphate disulfide, O, O O'-dipropyldithiophosphate disulfide, O, O'-diethyldithiophosphate disulfide, O, O'-dimethyldithiophosphate disulfide, O, O'-bis (2-ethylhexyl) dithiophosphate disulfide, O, O'-bis (4-methylpentyl) dithiophosphate disulfide, O, O'-dioctadecyldithiophosphate disulfide, O, O'-dibutyldithiophosphate tetrasulfide, O, O'-diisopropyldithiophosphate tetrasulfide, O, O'-dipropyl Dithiophosphoric acid tetrasulfide, O, O′-diethyldithiophosphate tetrasulfide, O, O′-dimethyldithiophosphate tetrasulfide, O, O′-bis (2-ethylhexyl) dithiophosphate tetrasulfide, O,
O'-bis (4-methylpentyl) dithiophosphate tetrasulfide, O, O'-dioctadecyldithiophosphate tetrasulfide and the like can be mentioned. Above all, from the point of effect,
O, O'-dibutyldithiophosphoric acid tetrasulfide,
O, O'-diisopropyldithiophosphate tetrasulfide and O, O'-bis (2-ethylhexyl) dithiophosphate tetrasulfide are preferred.

The dithiophosphate compound-based vulcanization accelerator is used in an amount of 0.1 to 10.0 parts by weight, preferably 0.2 to 5.0 parts by weight, more preferably 0.1 to 100 parts by weight, based on 100 parts by weight of the raw rubber. It is necessary to contain 5 to 3.0. If the amount is less than 0.1 part by weight, the controllability improvement effect after traveling is low, and if the amount is more than 10.0 parts by weight, further improvement of the effect is not recognized, and further increase from the economic point of view is not expected. Not effective.

The benzothiazole compound-based vulcanization accelerator used in another embodiment of the present invention has the general formula (III):
It is at least one selected from the group consisting of the compounds represented by (IV), (V) and (VI).

The above general formula (III) used in the present invention
R ^{3 of} a benzothiazole compound-based vulcanization accelerator represented by
And R ⁴ are each independently a hydrogen atom, an alkyl group having 1 to 8 carbon atoms or an aryl group having 6 to 10 carbon atoms, except for the case where they are simultaneously a hydrogen atom. To 6 alkyl groups or 6 to 6 carbon atoms
10 aryl groups, each more preferably a hydrogen atom, a methyl group, an ethyl group or a phenyl group.

These vulcanization accelerators include, for example, 2
-Mercapto-4-methylbenzothiazole, 2-mercapto-4-ethylbenzothiazole, 2-mercapto-5-methylbenzothiazole, 2-mercapto-5
Ethyl benzothiazole, 2-mercapto-6-methylbenzothiazole, 2-mercapto-6-ethylbenzothiazole, 2-mercapto-4,5-dimethylbenzothiazole, 2-mercapto-4,5-diethylbenzothiazole, 2- Mercapto-4-phenylbenzothiazole, 2-mercapto-5-phenylbenzothiazole, 2-mercapto-6-phenylbenzothiazole,
Bis- (4-methylbenzothiazolyl-2) disulfide, bis- (4-ethylbenzothiazolyl-2) disulfide, bis- (5-methylbenzothiazolyl-)
2) disulfide, bis- (5-ethylbenzothiazolyl-2) disulfide, bis- (6-methylbenzothiazolyl-2) disulfide, bis- (6-ethylbenzothiazolyl-2) Disulfide, bis- (4
5-dimethylbenzothiazolyl-2) disulfide,
Bis- (4,5-diethylbenzothiazolyl-2) disulfide, bis- (4-phenylbenzothiazolyl-)
2) Disulfide, bis- (5-phenylbenzothiazolyl-2) disulfide, bis- (6-phenylbenzothiazolyl-2) disulfide, and the like.
Among them, bis- (4-methylbenzothiazolyl-2) disulfide, bis- (5-methylbenzothiazolyl-)
2) Disulfide, mercapto-4-methylbenzothiazole and mercapto-5-methylbenzothiazole are preferred. These vulcanization accelerators can be used alone or in a mixture of two or more.

The method for producing these vulcanization accelerators is not particularly limited, but they can be easily produced using, for example, JP-A-49-93361.

The general formula (IV) used in the present invention,
The benzothiazole compound-based vulcanization accelerator represented by (V) or (VI) is an alkoxy group-containing 2-mercaptobenzothiazole compound and is used alone or in a mixture of two or more.

Where R^FiveIs an alkyl group having 1 to 8 carbon atoms,
Represents an alkenyl group or a cycloalkyl group;⁶Is hydrogen
Atom or -N (R⁷) R⁸Represents an amino group represented by
R⁷And R⁸Are each independently a hydrogen atom or 2 to 2 carbon atoms
4 represents an alkyl group or a cyclohexyl group (provided that
R⁷And R⁸Are simultaneously hydrogen atoms). R
⁹And R^TenIs independently alkyl having 1 to 8 carbon atoms
Represents an alkenyl group or a cycloalkyl group. X is Z
n atom, Cu atom or> NR¹³The amino group represented by
Represents, R¹³Is an alkyl group having 2 to 4 carbon atoms or cyclohexyl
Represents a sil group. R ¹¹And R¹²Is R⁹Is synonymous with

In these general formulas, the alkoxy groups -OR ⁵ , -OR ⁹ , -OR ¹⁰ , -OR ¹¹ and -OR ¹²
Each group is preferably independently a methoxy group, an ethoxy group or a butoxy group from the viewpoint of the effect, and more preferably an ethoxy group.

As the benzothiazole compound-based vulcanization accelerator represented by the general formula (IV), for example, 4-methoxy-2-mercaptobenzothiazole, 5-methoxy-2
-Mercaptobenzothiazole, 6-methoxy-2-mercaptobenzothiazole, 7-methoxy-2-mercaptobenzothiazole, 4-ethoxy-2-mercaptobenzothiazole, 5-ethoxy-2-mercaptobenzothiazole, 6-ethoxy-2 -Mercaptobenzothiazole, 7-ethoxy-2-mercaptobenzothiazole, 4-butoxy-2-mercaptobenzothiazole, 5-butoxy-2-mercaptobenzothiazole,
6-butoxy-2-mercaptobenzothiazole, 7-
Butoxy-2-mercaptobenzothiazole, N-te
rt-butyl-4-methoxy-2-benzothiazolylsulfenamide, N-tert-butyl-5-methoxy-2-benzothiazolylsulfenamide, N-ter
t-butyl-6-methoxy-2-benzothiazolylsulfenamide, N-tert-butyl-7-methoxy-
2-benzothiazolylsulfenamide, N-tert
-Butyl-4-ethoxy-2-benzothiazolylsulfenamide, N-tert-butyl-5-ethoxy-2
-Benzothiazolylsulfenamide, N-tert-
Butyl-6-ethoxy-2-benzothiazolylsulfenamide, N-tert-butyl-7-ethoxy-2-
Benzothiazolylsulfenamide, N-tert-butyl-4-butoxy-2-benzothiazolylsulfenamide, N-tert-butyl-5-butoxy-2-benzothiazolylsulfenamide, N-tert-butyl -6-butoxy-2-benzothiazolylsulfenamide, N-tert-butyl-7-butoxy-2-benzothiazolylsulfenamide, N-ethyl-4-methoxy-2-benzothiazolylsulfenamide, N-ethyl-5-methoxy-2-benzothiazolylsulfenamide, N-ethyl-6-methoxy-2-benzothiazolylsulfenamide, N-ethyl-7-methoxy-2
-Benzothiazolylsulfenamide, N-ethyl-4
-Ethoxy-2-benzothiazolylsulfenamide,
N-ethyl-5-ethoxy-2-benzothiazolylsulfenamide, N-ethyl-6-ethoxy-2-benzothiazolylsulfenamide, N-ethyl-7-ethoxy-2-benzothiazolylsulfenamide , N-ethyl-4-butoxy-2-benzothiazolylsulfenamide, N-ethyl-5-butoxy-2-benzothiazolylsulfenamide, N-ethyl-6-butoxy-2-
Benzothiazolylsulfenamide, N-ethyl-7-
Butoxy-2-benzothiazolylsulfenamide, N
-Cyclohexyl-4-methoxy-2-benzothiazolylsulfenamide, N-cyclohexyl-5-methoxy-2-benzothiazolylsulfenamide, N-cyclohexyl-6-methoxy-2-benzothiazolylsulfenamide, N-cyclohexyl-7-methoxy-2
-Benzothiazolylsulfenamide, N-cyclohexyl-4-ethoxy-2-benzothiazolylsulfenamide, N-cyclohexyl-5-ethoxy-2-benzothiazolylsulfenamide, N-cyclohexyl-
6-ethoxy-2-benzothiazolylsulfenamide, N-cyclohexyl-7-ethoxy-2-benzothiazolylsulfenamide, N-cyclohexyl-4-
Butoxy-2-benzothiazolylsulfenamide, N
-Cyclohexyl-5-butoxy-2-benzothiazolylsulfenamide, N-cyclohexyl-6-butoxy-2-benzothiazolylsulfenamide, N-cyclohexyl-7-butoxy-2-benzothiazolylsulfenamide, N, N-dicyclohexyl-4-methoxy-2-benzothiazolylsulfenamide, N, N-
Dicyclohexyl-5-methoxy-2-benzothiazolylsulfenamide, N, N-dicyclohexyl-6
Methoxy-2-benzothiazolylsulfenamide,
N, N-dicyclohexyl-7-methoxy-2-benzothiazolylsulfenamide, N, N-dicyclohexyl-4-ethoxy-2-benzothiazolylsulfenamide, N, N-dicyclohexyl-5-ethoxy-2-
Benzothiazolylsulfenamide, N, N-dicyclohexyl-6-ethoxy-2-benzothiazolylsulfenamide, N, N-dicyclohexyl-7-ethoxy-2-benzothiazolylsulfenamide, N, N-dicyclohexyl -4-butoxy-2-benzothiazolylsulfenamide, N, N-dicyclohexyl-5-butoxy-2-benzothiazolylsulfenamide, N,
N-dicyclohexyl-6-butoxy-2-benzothiazolylsulfenamide, N, N-dicyclohexyl-
7-butoxy-2-benzothiazolylsulfenamide; and the like.

Examples of the benzothiazole compound-based vulcanization accelerator represented by the general formula (V) include di-4-methoxy-2-benzothiazyl disulfide, di-5-methoxy-2-benzothiazyl disulfide, Di-6-methoxy-2-benzothiazyl disulfide, di-7-methoxy-2-benzothiazyl disulfide, di-4-ethoxy-2-benzothiazyl disulfide, di-5-ethoxy-2-benzothiazyl Disulfide, di-6-ethoxy-2-benzothiazyl disulfide, di-7-ethoxy-2-benzothiazyl disulfide, di-4-butoxy-2-benzothiazyl disulfide, di-5-butoxy-2-benzo Thiazyl disulfide, di-6-butoxy-2-benzothiazyl disulfide, di-7-butoxy-2-benzothia Disulphide, and the like.

Examples of the benzothiazole compound-based vulcanization accelerator represented by the general formula (VI) include 4-methoxy-2-mercaptobenzothiazole zinc salt, 5-methoxy-2-mercaptobenzothiazole zinc salt, -Methoxy-2-mercaptobenzothiazole zinc salt, 7-methoxy-2-mercaptobenzothiazole zinc salt, 4-
Ethoxy-2-mercaptobenzothiazole zinc salt, 5
-Ethoxy-2-mercaptobenzothiazole zinc salt,
6-ethoxy-2-mercaptobenzothiazole zinc salt, 7-ethoxy-2-mercaptobenzothiazole zinc salt, 4-butoxy-2-mercaptobenzothiazole zinc salt, 5-butoxy-2-mercaptobenzothiazole zinc salt, 6- Butoxy-2-mercaptobenzothiazole zinc salt, 7-butoxy-2-mercaptobenzothiazole zinc salt, 4-methoxy-2-mercaptobenzothiazole copper salt, 5-methoxy-2-mercaptobenzothiazole copper salt, 6-methoxy- 2-mercaptobenzothiazole copper salt, 7-methoxy-2-mercaptobenzothiazole copper salt, 4-ethoxy-2-mercaptobenzothiazole copper salt, 5-ethoxy-2-mercaptobenzothiazole copper salt, 6-ethoxy-2- Mercaptobenzothiazole copper salt, 7- Copper salt of toxic-2-mercaptobenzothiazole, copper salt of 4-butoxy-2-mercaptobenzothiazole, copper salt of 5-butoxy-2-mercaptobenzothiazole, copper salt of 6-butoxy-2-mercaptobenzothiazole, 7-butoxy- 2-mercaptobenzothiazole copper salt, N-ethyl- (4-methoxy-2-benzothiazolyl) sulfenimide, N-ethyl- (5-
Methoxy-2-benzothiazolyl) sulfenimide,
N-ethyl- (6-methoxy-2-benzothiazolyl)
Sulfenimide, N-ethyl- (7-methoxy-2-
Benzothiazolyl) sulfenimide, Nt-butyl (4-methoxy-2-benzothiazolyl) sulfenimide, Nt-butyl (5-methoxy-2-benzothiazolyl) sulfenimide, Nt-butyl (6- Methoxy-2-benzothiazolyl) sulfenimide, N-
t-butyl (7-methoxy-2-benzothiazolyl) sulfenimide, N-cyclohexyl (4-methoxy-
2-benzothiazolyl) sulfenimide, N-cyclohexyl (5-methoxy-2-benzothiazolyl) sulfenimide, N-cyclohexyl (6-methoxy-2)
-Benzothiazolyl) sulfenimide, N-cyclohexyl (7-methoxy-2-benzothiazolyl) sulfenimide, N-ethyl- (4-ethoxy-2-benzothiazolyl) sulfenimide, N-ethyl- (5-ethoxy-2) -Benzothiazolyl) sulfenimide, N
-Ethyl- (6-ethoxy-2-benzothiazolyl) sulfenimide, N-ethyl- (7-ethoxy-2-benzothiazolyl) sulfenimide, Nt-butyl (4-ethoxy-2-benzothiazolyl) sulfenimide , Nt-butyl (5-ethoxy-2-benzothiazolyl) sulfenimide, Nt-butyl (6-ethoxy-2-benzothiazolyl) sulfenimide, N-
t-butyl (7-ethoxy-2-benzothiazolyl) sulfenimide, N-cyclohexyl (4-ethoxy-
2-benzothiazolyl) sulfenimide, N-cyclohexyl (5-ethoxy-2-benzothiazolyl) sulfenimide, N-cyclohexyl (6-ethoxy-2)
-Benzothiazolyl) sulfenimide, N-cyclohexyl (7-ethoxy-2-benzothiazolyl) sulfenimide, N-ethyl- (4-butoxy-2-benzothiazolyl) sulfenimide, N-ethyl- (5-butoxy-2) -Benzothiazolyl) sulfenimide, N
-Ethyl- (6-butoxy-2-benzothiazolyl) sulfenimide, N-ethyl- (7-butoxy-2-benzothiazolyl) sulfenimide, Nt-butyl (4-butoxy-2-benzothiazolyl) sulfenimide , Nt-butyl (5-butoxy-2-benzothiazolyl) sulfenimide, Nt-butyl (6-butoxy-2-benzothiazolyl) sulfenimide, N-
t-butyl (7-butoxy-2-benzothiazolyl) sulfenimide, N-cyclohexyl (4-butoxy-
2-benzothiazolyl) sulfenimide, N-cyclohexyl (5-butoxy-2-benzothiazolyl) sulfenimide, N-cyclohexyl (6-butoxy-2)
-Benzothiazolyl) sulfenimide, N-cyclohexyl (7-butoxy-2-benzothiazolyl) sulfenimide, and the like.

In these benzothiazole compound vulcanization accelerators, the position of the alkoxy group contained in the general formulas (IV), (V) and (VI) on the aromatic monocycle is the 4-position or the 6-position. And more preferably the 4-position. In addition, a benzothiazole compound having an alkoxy group at the 4- or 6-position of the aromatic monocycle is preferable in terms of availability of raw materials and ease of synthesis. In addition, benzothiazolylsulfenamide, benzothiazyldisulfide, and benzothiazolylsulfenimide having an alkoxy group at the 4- or 6-position of the aromatic monocycle are also preferable from the viewpoint of scorch properties. Further, a compound having an alkoxy group at the 4-position of the aromatic monocyclic ring is more preferable because it suppresses curing during thermal aging of the rubber composition.

The method for producing these vulcanization accelerators is not particularly limited, but they can be easily produced using, for example, JP-A-49-93361.

The amount of the benzothiazole compound vulcanization accelerator used in the present invention is 0.1 to 10 parts by weight, preferably 0.5 to 5.0 parts by weight, based on 100 parts by weight of the rubber raw material. If the amount is less than 0.1 part by weight, sufficient effects cannot be obtained. If the amount exceeds 10 parts by weight, not only no more effect can be obtained, but also the workability such as scorch properties deteriorates.

The dithiophosphate compound-based vulcanization accelerator and the benzothiazole compound-based vulcanization accelerator described above may be used alone or in combination.

These vulcanization accelerators used in the present invention include, in addition to these, general-purpose vulcanization accelerators such as 2-mercaptobenzothiazyl disulfide, Nt-butylbenzothiazolylsulfenamide, and N-cyclohexylbenzo. Thiazole vulcanization accelerators such as thiazolyl sulfenamide and thiuram vulcanization accelerators such as tetra (2-ethylhexyl) thiuram disulfide and tetramethylthiuram disulfide can be appropriately compounded.

The components such as carbon black, silica, zinc oxide, stearic acid, an antioxidant, a wax, a silane coupling agent and a vulcanizing agent, which are usually used together with the above essential components, are used as the rubber composition of the present invention. It can be appropriately blended within a range that does not impair the effect.

As carbon black, for example, SA
F, ISAF, HAF, FEF, GPF and the like are preferable.
The amount of carbon black is preferably 5 to 80 parts by weight based on 100 parts by weight of the rubber component. If the amount exceeds 80 parts by weight, heat generation and workability are significantly deteriorated, which is not preferable. The amount is more preferably 25 to 60 weight from the viewpoint of reinforcing properties and low heat generation.

Examples of the vulcanizing agent include sulfur and the like, and the amount used is 0.1 to 5 parts by weight, preferably 1 to 2 parts by weight, based on 100 parts by weight of the raw rubber. If the amount is less than 0.1 part by weight, the breaking strength and abrasion resistance of the vulcanized rubber decrease, and if it exceeds 5 parts by weight, the rubber elasticity is impaired.

The rubber composition of the present invention is obtained by kneading using a kneading machine such as a roll, an internal mixer, a Banbury mixer, etc., and after molding, vulcanization is carried out to obtain tires, conveyor belts, rubber hoses and the like. It can be applied to any rubber products. However, it is particularly suitably used for a tread of a tire, and in this case, it is possible to suppress a decrease in steering stability due to rubber curing during use.

The rubber of the tread portion of the tire used in the present invention (rubber containing various compounding agents according to the present invention) may be applied to a rubber having a single tread portion, or a radial tread portion. In the case where the tread rubber is composed of two layers of the cap rubber disposed on the outer side in the direction and the base rubber disposed on the inner side in the radial direction, the tread rubber is more preferably applied to the base rubber. More preferably, it is applied to both rubbers or base rubbers.

[0059]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, which should not be construed as limiting the scope of the present invention.

The methods for measuring various physical properties are as follows.・ Mooney viscosity (ML _{1 + 4} ) RLM-01 type tester manufactured by Toyo Seiki Co., Ltd.
It measured based on K6300-1994.

Mooney scorch test Measured at 130 ° C. based on JIS K6300-1974. The MST (Mooney scorch time) in the Mooney scorch test is the time until rubber burnout during rubber molding such as extrusion and calendering.

-Initial fracture properties For samples before heat aging, JIS K6301 (1
995), a tensile test was performed, and a tensile strength (T
b), elongation (Eb) and tensile stress at 200% elongation (M200) were determined.

Fracture characteristics after heat aging The heat aging was performed in a gear oven at 100 ° C. for 48 hours.
And M200 were determined.

M200 curing rate An index indicating the degree of deterioration, and is a value calculated from the following equation. The closer the value is to 100, the harder it is to deteriorate.

[0065]

(Equation 1)

(Examples 1 to 8) (Comparative Examples 1 and 2) According to the compounding recipes shown in Tables 1 and 2, kneading was carried out using an ordinary Banbury mixer to prepare a rubber composition. Mooney viscosity and Mooney scorch time were measured. This rubber composition was measured for T9 at 145 ° C. using MDR2000 manufactured by Flexis (formerly Monsanto) in the United States.
Vulcanization was carried out at 145 ° C. for a time corresponding to 1.5 to 2.0 times the 0 value. With respect to this vulcanized product, the initial fracture characteristics, the fracture characteristics after thermal aging, and the M200 curing rate were measured. The results are shown in Tables 3 and 4.

[0067]

[Table 1]

[0068]

[Table 2]

[0069]

[Table 3]

[0070]

[Table 4]

As shown in Tables 3 and 4, the rubber composition of the present invention and the pneumatic tire using the same have excellent fracture characteristics before aging, as well as excellent fracture characteristics after aging, heat aging resistance, and heat curing resistance. It can be seen that is improved.

[0072]

The rubber composition of the present invention and the pneumatic tire using the rubber composition of the present invention have the above-described structure, and therefore have an excellent effect of improving the heat aging resistance, particularly the heat hardening resistance and the breaking characteristics. Play.

Claims (12)

[Claims] In a tread portion of a pneumatic tire, the rubber of the tread portion is based on 100 parts by weight of raw rubber made of at least one kind of rubber selected from the group consisting of natural rubber and diene-based synthetic rubber. The following general formula (A),
(B) containing 0.1 to 10.0 parts by weight of at least one polyoxyethylene alkylamine derivative represented by (C), (D), (E) or (F);
Vulcanization acceleration of at least one dithiophosphate compound selected from the group consisting of metal dithiophosphates represented by (I), O, O'-dialkyldithiophosphate disulfide and O, O'-dialkyldithiophosphate tetrasulfide 0.1 to 10.0 with respect to 100 parts by weight of the raw rubber.
A rubber composition comprising parts by weight. Embedded image (Wherein, R is independently of each of the formulas (A) to (F),
Represents an alkyl group of -20, x represents an integer of 0-5,
y and z represent an integer of 1 to 5, and n represents an integer of 1 to 10. ) (Wherein, R ¹ and R ² are each independently a C 1-8
Represents an alkyl group or an aryl group having 6 to 10 carbon atoms.
This alkyl group may be linear, branched or cyclic. M ¹ represents a Zn atom, an Sb atom, an Fe atom or a Cu atom, and n represents the number of valences of the metal to be bonded. ) 2. The rubber composition according to claim 1, wherein the polyoxyethylene alkylamine derivative represented by the general formula is represented by the formula (A) or (B). 3. The rubber composition according to claim 1, wherein the polyoxyethylene alkylamine derivative represented by the general formula is represented by the formula (A), and x = 1. 4. The method according to claim 1, wherein the metal dithiophosphate represented by the general formula (I) is a dithiophosphate compound-based vulcanization accelerator represented by the following general formula (II). Pneumatic tire. Embedded image (In the formula, M ² represents a Zn atom or an Sb atom, and n represents the number of valences of the metal to be bonded.) 5. In a tread portion of a pneumatic tire, the rubber of the tread portion is based on 100 parts by weight of raw rubber made of at least one kind of rubber selected from the group consisting of natural rubber and diene-based synthetic rubber. The polyoxyethylene alkylamine derivative represented by the general formula (A), (B), (C), (D), (E) or (F) according to claim 1 is used in an amount of 0.1 to 10%. At least one benzothiazole compound-based vulcanization accelerator selected from the group consisting of compounds represented by the following general formulas (III), (IV), (V) and (VI). The raw material rubber 1
A rubber composition comprising 0.1 to 10.0 parts by weight based on 00 parts by weight. Embedded image Embedded image Embedded image Embedded image (Wherein, R ³ and R ⁴ each independently represent a hydrogen atom, an alkyl group having 1 to 8 carbon atoms or an aryl group having 6 to 10 carbon atoms, provided that R ³ and R ⁴ are simultaneously a hydrogen atom. unless .R ⁵ represents an alkyl group having 1 to 8 carbon atoms, an alkenyl group or a cycloalkyl group, R ⁶ represents an amino group represented by hydrogen or ^{-N (R 7) R 8,} R 7 and R ⁸ each independently represent a hydrogen atom or an alkyl group or a cyclohexyl group having 2 to 4 carbon atoms. However, .R ⁹ and R ¹⁰ except when R ⁷ and R ⁸ are not hydrogen atoms at the same time
Each independently represents an alkyl group, alkenyl group or cycloalkyl group having 1 to 8 carbon atoms. X is a Zn atom, Cu
An amino group represented by atom or> N-R ^13, R ¹³ represents an alkyl group or a cyclohexyl group having 2 to 4 carbon atoms. R ¹¹ and R ¹² have the same meaning as R ⁹ . ) 6. The rubber composition according to claim 5, wherein the polyoxyethylene alkylamine derivative represented by the general formula is represented by the formula (A) or (B). 7. The rubber composition according to claim 5, wherein the polyoxyethylene alkylamine derivative represented by the general formula is the formula (A), and x = 1. 8. The benzothiazole compound-based vulcanization accelerator represented by the general formula (III) according to claim 5, wherein R ³ and R ⁴ are each independently a hydrogen atom, a methyl group, an ethyl group or a phenyl group. The rubber composition according to claim 5, which is a group (except that R ³ and R ⁴ are simultaneously a hydrogen atom). 9. The benzothiazole compound-based vulcanization accelerator represented by the general formula (III) according to claim 5, wherein
(4-methylbenzothiazolyl-2) disulfide,
It is at least one selected from the group consisting of bis- (5-methylbenzothiazolyl-2) disulfide, mercapto-4-methylbenzothiazole and mercapto-5-methylbenzothiazole. 5. The rubber composition according to 5. 10. The general formula (IV) according to claim 5,
The rubber composition according to claim 5, wherein the alkoxy group of the benzothiazole compound-based vulcanization accelerator represented by (V) or (VI) is located at the 4-position or 6-position in the aromatic monocycle. Stuff. 11. The general formula (IV) according to claim 5,
6. The benzothiazole compound-based vulcanization accelerator represented by (V) or (VI), wherein the alkoxy group is a group selected from the group consisting of a methoxy group, an ethoxy group and a butoxy group. Rubber composition. 12. A pneumatic tire, wherein the rubber composition according to claim 1 is applied to a tire tread.