JP2010163593A - Rubber composition for bead filler and tire using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rubber composition for bead fillers excellent in durability of the bead fillers. <P>SOLUTION: The rubber composition for bead fillers includes a sulfenamide-based vulcanization accelerator expressed by general formula (I). In the formula (I), R<SP>1</SP>represents 3-12C branched alkyl; R<SP>2</SP>represents 1-10C straight chain alkyl or 3-10C branched alkyl; R<SP>3</SP>to R<SP>6</SP>each represent H, 1-4C straight chain alkyl or alkoxy, or 3-4C branched alkyl or alkoxy, and they can be the same or different; x denotes an integer of 1 or 2; n denotes an integer of 0 or 1. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a rubber composition for a bead filler and a tire using the same, and more specifically, sufficient co-curability between a bead filler and an inner liner or a ply coating rubber which is a member adjacent to the bead filler. The present invention relates to a bead filler rubber composition excellent in durability of a bead filler disposed in a bead portion of a tire by strengthening the adhesion and a tire using the same.

The bead filler disposed in the bead portion of the tire is required to have high rigidity and high durability in order to maintain the shape of the tire.
In order to maintain high durability, it is necessary to ensure sufficient adhesion with adjacent members (play coating rubber, inner liner, etc.) in addition to enhancing the durability of the bead filler itself.

  Adhesion between the tire bead filler and the adjacent inner liner and ply coating rubber is usually performed by co-vulcanization, but for co-vulcanization, the vulcanization characteristics of the adjacent rubber member are close. You need to choose one.

  Conventionally, as vulcanization accelerators used for tire bead fillers, CZ (N-cyclohexyl-2-benzothiazylsulfenamide), NS (Nt-butylbenzothiazole-2-sulfenamide), DZ ( N, N′-dicyclohexyl-2-benzothiazylsulfenamide) has been used, and even these vulcanization accelerators have had sufficient adhesion, but further improvements are required. In addition, NS and DM (di-2-benzothiazolyl disulfide) are used for the ply coating rubber which is an adjacent member, but even in these vulcanization accelerators, further sufficient adhesion is achieved. From the point of securing, further improvement is required.

  The applicant of the present application includes a pair of left and right bead parts, a side wall part connected to the bead part, a tread part located between the side wall parts, and a carcass ply extending across a bead core disposed in the bead part. The carcass ply includes a bead filler that is folded back from the inner side to the outer side of the bead core to form a pair of left and right folded parts and that extends upward between the carcass ply on the bead core and the folded part. In the pneumatic tire, the rubber composition constituting the bead filler is mercapto-4-methylbenzothiazole, mercapto-5-methylbenzothiazole, bis (4) as a vulcanization accelerator with respect to 100 parts by weight of the rubber component. -Methylbenzothiazolyl-2) -disulfide and bis (5-methylbenzothiazolyl-2) -Pneumatic in which 0.3 to 8.0 parts by weight of at least one selected from the group consisting of disulfide and the like is contained, and the tensile stress at 50% elongation of the rubber composition is 2.9 MPa or more A tire application has been filed (see, for example, Patent Document 1).

The rubber composition for bead filler described in Patent Document 1 is excellent in the durability of the bead filler, but more firmly bonds the bead filler rubber to the inner liner and ply coating rubber which are adjacent members. In addition, the rubber composition for bead filler and tires using the bead filler that have higher durability are currently desired.
JP-A-10-95875 (Claims, Examples, etc.)

  In view of the above-described conventional problems, the present invention intends to solve this problem. The co-curability between the bead filler and the adjacent inner liner, ply coating rubber, and the like is sufficient, and adhesion between them is achieved. An object of the present invention is to provide a rubber composition for a bead filler and a tire using the same, which is excellent in durability of the bead filler.

  As a result of intensive studies on the above-mentioned conventional problems and the like, the present inventors have used the sulfenamide-based vulcanization accelerator having specific physical properties as the compounding component of the bead filler rubber, thereby achieving the above-mentioned objective bead filler rubber. The present inventors have found that a composition and a tire using the composition can be obtained, and have completed the present invention.

（２） ゴム成分１００質量部に対し、上記一般式（Ｉ）で表されるスルフェンアミド系加硫促進剤０．１〜１０質量部を含有してなる上記（１）に記載のビードフィラー用ゴム組成物。
（３） ゴム成分１００質量部に対し、硫黄０．１〜１０質量部を含有してなる上記（１）に記載のビードフィラー用ゴム組成物。
（４） ゴム成分１００質量部に対し、硫黄０．１〜１０質量部と、上記一般式（Ｉ）で表されるスルフェンアミド系加硫促進剤０．１〜１０質量部とを含有してなる上記（１）に記載のビードフィラー用ゴム組成物。
（５） 前記ゴム組成物における一般式（Ｉ）中のＲ¹及びＲ²における分岐アルキル基は、α位に分岐を有する上記（１）に記載のゴム組成物。
（６） 前記ゴム組成物における一般式（Ｉ）中のＲ¹は、ｔｅｒｔ−ブチル基であり、ｎ＝０である上記（１）に記載のゴム組成物。
（７） 前記ゴム組成物における一般式（Ｉ）中のＲ¹は、ｔｅｒｔ−ブチル基であり、Ｒ²は、炭素数１〜６の直鎖アルキル基又は炭素数３〜６の分岐アルキル基であり、Ｒ³〜Ｒ⁶は、水素原子である上記（１）に記載のゴム組成物。
（８） 前記ゴム組成物における一般式（Ｉ）中のＲ¹は、ｔｅｒｔ−ブチル基であり、ｎ＝０であり、Ｒ²は、炭素数１〜６の直鎖アルキル基又は炭素数３〜６の分岐アルキル基であり、Ｒ³〜Ｒ⁶は、水素原子である上記（１）に記載のゴム組成物。
（９） 前記ゴム組成物における一般式（Ｉ）中のＲ¹は、ｔｅｒｔ−ブチル基であり、ｎ＝０であり、Ｒ²はメチル基、エチル基、ｎ−プロピル基であり、Ｒ³〜Ｒ⁶は、水素原子である上記（１）に記載のゴム組成物。
（１０） 前記ゴム組成物における一般式（Ｉ）中のＲ¹は、ｔｅｒｔ−ブチル基であり、ｎ＝０であり、Ｒ²はエチル基であり、Ｒ³〜Ｒ⁶は、水素原子である上記（１）に記載のゴム組成物。
（１１） ゴム成分が、天然ゴム及びポリイソプレンゴムの少なくとも一方を含む上記（１）〜（１０）の何れか一つに記載のビードフィラー用ゴム組成物。
（１２） 上記（１）〜（１１）の何れか一つに記載のビードフィラー用ゴム組成物をビードフィラーに用いたことを特徴とするタイヤ。
（１３） 上記（１）〜（１１）の何れか一つに記載のビードフィラー用ゴム組成物をビードフィラーに用い、かつ、上記一般式（Ｉ）で表されるスルフェンアミド系加硫促進剤を含有したゴム組成物をサイド補強層に用いたことを特徴とするランフラットタイヤ。 That is, the present invention resides in the following (1) to (13).
(1) A rubber composition for bead filler, comprising a rubber component, sulfur, and a sulfenamide-based vulcanization accelerator represented by the following general formula (I).

(2) The bead filler according to (1), comprising 0.1 to 10 parts by mass of the sulfenamide vulcanization accelerator represented by the general formula (I) with respect to 100 parts by mass of the rubber component. Rubber composition.
(3) The rubber composition for bead fillers according to (1) above, containing 0.1 to 10 parts by mass of sulfur with respect to 100 parts by mass of the rubber component.
(4) It contains 0.1 to 10 parts by mass of sulfur and 0.1 to 10 parts by mass of the sulfenamide vulcanization accelerator represented by the above general formula (I) with respect to 100 parts by mass of the rubber component. The rubber composition for bead fillers according to (1) above.
(5) The rubber composition according to (1), wherein the branched alkyl group in R ¹ and R ² in the general formula (I) in the rubber composition has a branch at the α-position.
(6) The rubber composition according to (1), wherein R ¹ in the general formula (I) in the rubber composition is a tert-butyl group and n = 0.
(7) R ¹ in the general formula (I) in the rubber composition is a tert- butyl group, R ² is a linear alkyl group or branched alkyl group having 3 to 6 carbon atoms having 1 to 6 carbon atoms The rubber composition according to (1), wherein R ^{3 to} R ⁶ are hydrogen atoms.
(8) R ¹ in the general formula (I) in the rubber composition is a tert-butyl group, n = 0, and R ² is a linear alkyl group having 1 to 6 carbon atoms or 3 carbon atoms. The rubber composition according to the above (1), which is a branched alkyl group of ˜6, and R ^{3 to} R ⁶ are hydrogen atoms.
(9) R ¹ in the general formula (I) in the rubber composition is a tert-butyl group, n = 0, R ² is a methyl group, an ethyl group, or an n-propyl group, and R ³ to R ^6, the rubber composition according to the above (1) is a hydrogen atom.
(10) R ¹ in the general formula (I) in the rubber composition is a tert-butyl group, n = 0, R ² is an ethyl group, and R ^{3 to} R ⁶ are hydrogen atoms. The rubber composition as described in (1) above.
(11) The rubber composition for bead filler according to any one of (1) to (10), wherein the rubber component includes at least one of natural rubber and polyisoprene rubber.
(12) A tire comprising the bead filler rubber composition according to any one of (1) to (11) above.
(13) Using the rubber composition for bead filler according to any one of (1) to (11) as a bead filler, and promoting sulfenamide-based vulcanization represented by the general formula (I) A run-flat tire characterized in that a rubber composition containing an agent is used for a side reinforcing layer.

ADVANTAGE OF THE INVENTION According to this invention, the rubber composition for bead fillers excellent in the durability of a bead filler and a tire using the same are provided.
Further, a tire using the rubber composition for bead filler of the present invention as a bead filler and a rubber composition containing a sulfenamide vulcanization accelerator represented by the general formula (I) as a side reinforcing layer Then, a run flat tire excellent in run flat durability can be obtained.

Hereinafter, embodiments of the present invention will be described in detail.
The rubber composition for bead filler of the present invention is characterized by containing a rubber component, sulfur, and a sulfenamide-based vulcanization accelerator represented by the following general formula (I). .

The rubber component used in the present invention is not particularly limited as long as it is a rubber used for a tire bead filler, and any rubber having a double bond in the main chain (diene rubber) can be sulfur-crosslinked. The sulfenamide vulcanization accelerator represented by the formula (I) functions, and for example, natural rubber and / or diene synthetic rubber is used. Specifically, at least one of natural rubber, polyisoprene rubber, styrene-butadiene copolymer, polybutadiene rubber, isoprene rubber, ethylene-propylene-diene copolymer, chloroprene rubber, halogenated butyl rubber, acrylonitrile-butadiene rubber and the like. Can be used.
Preferably, it is desirable to include at least one of natural rubber and polyisoprene rubber from the viewpoint of breaking strength.

  The sulfenamide-based vulcanization accelerator represented by the above general formula (I) of the present invention has a vulcanization delay effect equivalent to DZ (N, N-dicyclohexyl-2-benzothiazolylsulfenamide), In addition, the rubber composition for bead filler is sufficient for co-curability of the bead filler used in tires and the inner liner and ply coating rubber which are adjacent members, and has excellent adhesion durability in direct vulcanization adhesion. It can be suitably used for products.

Furthermore, among the sulfenamide vulcanization accelerators represented by the above general formula (I), in particular, R ¹ is a tert-butyl group, x = 1 or 2, n = 0, R ² is more preferably a straight chain, but among the straight chains, a methyl group, an ethyl group, an n-propyl group, and an n-butyl group are most preferable, and a methyl group and an ethyl group are most preferable, and R ^{3 to} R ⁶ are preferable. It is most preferable to use a sulfenamide compound, which is a hydrogen atom, as a vulcanization accelerator in terms of adhesion and vulcanization delay effect. These sulfenamide vulcanization accelerators are used as vulcanization accelerators for the first time in the present invention, and are the slowest in the vulcanization reaction among the conventional sulfenamide vulcanization accelerators. N, N-dicyclohexyl-2-benzothiazolylsulfenamide, which is known as a vulcanization accelerator that gives a sufficient vulcanization retarding effect, while having sufficient vulcanization acceleration ability, and bead filler And the inner liner and the ply coating rubber which are adjacent members thereof are sufficiently co-cured and have excellent adhesion durability in direct vulcanization adhesion. Therefore, it can be suitably used for tire bead fillers, side reinforcing rubbers, and the like.

In the present invention, R ¹ in the sulfenamide compound represented by the general formula (I) represents a branched alkyl group having 3 to 12 carbon atoms. When R ¹ is a branched alkyl group having 3 to 12 carbon atoms, the vulcanization acceleration performance of the compound represented by the general formula (I) is good, and sufficient co-vulcanization is performed to improve the adhesion performance. Can do.
Specific examples of R ¹ of the compound represented by the general formula (I) include isopropyl group, isobutyl group, sec-butyl group, tert-butyl group, isoamyl group (isopentyl group), neopentyl group, tert-amyl group. (Tert-pentyl group), isohexyl group, tert-hexyl group, isoheptyl group, tert-heptyl group, isooctyl group, tert-octyl group, isononyl group, tert-nonyl group, isodecyl group, tert-decyl group, isoundecyl group, Examples thereof include a tert-undecyl group, an isododecyl group, and a tert-dodecyl group.
Among these, R ¹ preferably has a branch at the α-position from the viewpoints of vulcanization speed, adhesiveness, human body accumulation, etc., and more preferably has 3 carbon atoms from the viewpoint of further manifesting the effects of the present invention. ~ 12 tert-alkyl groups are preferred, and in particular, tert-butyl group, tert-amyl group (tert-pentyl group), tert-dodecyl group, triisobutyl group, among which tert-butyl group is a synthetic surface, from the viewpoint of obtaining raw materials Therefore, it is particularly desirable from the viewpoint of further adhesiveness because it provides a vulcanization rate equivalent to that of DCBS (DZ).

Moreover, R < ² > in the sulfenamide compound represented by the said general formula (I) represents a C1-C10 linear or C3-C10 branched alkyl group. If R ² is a straight chain having 1 to 10 carbon atoms or a branched alkyl group having 3 to 10 carbon atoms, the vulcanization acceleration performance of the compound represented by the general formula (I) is good and co-vulcanization is performed. The adhesion performance can be further improved.
Specific examples of R ² of the compound represented by the general formula (I) include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl. Group, n-amyl group (n-pentyl group), isoamyl group (isopentyl group), neopentyl group, tert-amyl group (tert-pentyl group), n-hexyl group, isohexyl group, n-heptyl group, isoheptyl group, Examples thereof include an n-octyl group, an iso-octyl group, a nonyl group, an isononyl group, and a decyl group. Among these, from the viewpoint of effects such as ease of synthesis and raw material costs, a straight chain having 1 to 8 carbon atoms or a branched alkyl group having 3 to 8 carbon atoms, and further a straight chain having 1 to 6 carbon atoms or 3 carbon atoms. It is preferably a branched alkyl group of ˜6, and a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, and a sec-butyl group are preferable. When R ² is a branched alkyl group having 3 to 10 carbon atoms, R ² preferably has a branch at the α-position from the viewpoints of vulcanization speed, adhesiveness, low human body accumulation and the like.
Particularly preferably, the above-mentioned branching of carbon number is used in that the co-curability of the bead filler and the adjacent inner liner and ply coating rubber is further sufficient, and the adhesion durability in the direct vulcanization adhesion is further improved. A linear alkyl group having the above carbon number is more desirable than an alkyl group. This is because when branched, the vulcanization is further delayed, so that the productivity is lowered or the adhesiveness is lowered when compared with the same carbon number as that of the linear alkyl group. Among these, a methyl group, an ethyl group, an n-propyl group, and an n-butyl group, which are linear alkyl groups having 4 or less carbon atoms, are most desirable.
R ^{3 to} R ⁶ in the sulfenamide compound represented by the general formula (I) are each a hydrogen atom, a linear alkyl group having 1 to 4 carbon atoms or an alkoxy group, and a branched chain having 3 to 4 carbon atoms. An alkyl group or an alkoxy group, which may be the same or different. Among them, R ³ and R ⁵ are each a linear alkyl group or alkoxy group having 1 to 4 carbon atoms, or 3 to 4 carbon atoms. It is preferably a branched alkyl group or alkoxy group. Moreover, when R < ³ > -R < ⁶ > is a C1-C4 alkyl group or an alkoxy group, it is preferable that it is C1 and it is especially preferable that it is a hydrogen atom. This is because in any case, the ease of synthesis of the compound and the vulcanization rate do not slow down.
Specific examples of R ^{3 to} R ⁶ of the sulfenamide compound represented by the general formula (I) include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec- Examples include butyl group, tert-butyl group, methoxy group, ethoxy group, n-propoxy group, isopropoxy group, n-butoxy group, isobutoxy group, sec-butoxy group, and tert-butoxy group.

In the present invention, when R ¹ and R ² in the sulfenamide compound represented by the general formula (I) are both branched alkyl groups, the vulcanization rate is equivalent to that of DCBS (DZ), and R ¹ is a tert-butyl group, R ² is an isopropyl group, 1-methylpropyl group, and R ^{3 to} R ⁶ are a combination of hydrogen atoms. preferable. When R ¹ and R ² are branched alkyl groups other than the above combinations, the difficulty of synthesis increases.

Further, as a particularly preferred combination of R ¹ and R ^{2 in} the sulfenamide compound represented by the general formula (I), R ¹ is a tert-butyl group, and R ² is a straight chain having 1 to 10 carbon atoms. The chain alkyl group, R ^{3 to} R ^6, is a combination of hydrogen atoms. Among these combinations, the best mode combination is when R ¹ is a tert-butyl group and R ² is a methyl group, ethyl group, n-propyl group, or n-butyl group having 4 or less carbon atoms. More preferably, in the case of this combination in which R ² has 3 or less carbon atoms, particularly preferably 2 or less carbon atoms, the vulcanization rate is equivalent to that of DCBS (DZ), further ensuring adhesion performance, and human body accumulation. The best balance of performance from the viewpoint of.
The combination which becomes the best mode can be confirmed from the numerical value of the octanol / water partition coefficient (log POW) which is one of simple measures for evaluating the condensability of chemicals. In the present invention, the smaller the value of logP, the better the balance between the vulcanization speed, adhesion performance securing, and human body accumulation.
In the present invention (including the examples described later), the octanol / water partition coefficient (log P) can be measured by a high performance liquid chromatography method in accordance with JIS Z 7260-117 (2006). Is defined by the following equation.
logP = log ("Co" / "Cw")
C0: Test substance concentration in the 1-octanol layer Cw: Test substance concentration in the water layer

In the sulfenamide compound represented by the above general formula (I), x represents an integer of 1 or 2, and n represents an integer of 0 or 1, which is advantageous in terms of effects such as ease of synthesis and raw material costs. In view of this, n is preferably 0.
As described above, when the more preferable compounds among the sulfenamide compounds represented by the general formula (I) used in the present invention are further summarized in order, specifically, the Mooney scorch time is faster. 1) R ¹ of the above general formula (I) is a tert-butyl group, and n = 0, R ² is a linear alkyl group having 1 to 10 carbon atoms or a branched alkyl group having 3 to 10 carbon atoms, R ^{3 to} R ⁶ are hydrogen atoms, and 2) the above general formula (I) R ¹ therein is a tert-butyl group, n is an integer of 0 or 1, R ² is a linear alkyl group having 1 to 6 carbon atoms or a branched alkyl group having 3 to 6 carbon atoms, R ³ to R ⁶ are, are hydrogen atoms, 3) R ¹ in the general formula (I), t an rt- butyl group, a n = 0, R ² is a straight chain alkyl group or branched alkyl group having 3 to 6 carbon atoms having 1 to 6 carbon atoms, R ³ to R ⁶ is a hydrogen atom 4) R ¹ in the above general formula (I) is a tert-butyl group, n = 0, and R ² is a linear alkyl group having 4 or less carbon atoms (preferably having 3 or less carbon atoms). Linear alkyl group), R ^{3 to} R ⁶ are hydrogen atoms, 5) R ¹ in the above general formula (I) is a tert-butyl group, n = 0, R ² Is a straight-chain alkyl group (methyl group, ethyl group) having 2 or less carbon atoms, and R ^{3 to} R ⁶ are preferably hydrogen atoms (the more descending, the more suitable sulfenamide compounds are obtained). ).
In addition, each functional group (for example, n-octadecyl group etc.) other than the branched alkyl group having 3 to 12 carbon atoms or R ¹ in the sulfenamide compound represented by the general formula (I) has 12 carbon atoms. When it is a branched alkyl group that exceeds, R ² represents a functional group other than a straight chain having 1 to 10 carbon atoms or a branched alkyl group having 3 to 10 carbon atoms (for example, n-octadecyl group, etc.) or 10 carbon atoms. When it is a linear or branched alkyl group exceeding, when R ^{3 to} R ⁶ are further outside the above functional groups and carbon numbers, or when n is 2 or more, the present invention It is less likely to exert the intended effect, and the preferred Mooney scorch time is delayed and the vulcanization time is prolonged, resulting in a decrease in productivity, or a decrease in adhesiveness, or a vulcanization performance as an accelerator. Rubber performance may decrease Further, when x is 3 or more, it is not preferable in terms of stability. In addition, when R ¹ and R ² in the sulfenamide compound represented by the general formula (I) are each a branched alkyl group, those having a branch other than the α-position, such as 2-ethylhexyl, 2- In the case of ethyl butyl, etc., the balance between the vulcanization speed, adhesion performance securing, and human body accumulation tends to deteriorate, so it is desirable that the α position has a branch.

In the present invention, typical examples of the compound represented by the general formula (I) include N-methyl-Nt-butylbenzothiazol-2-sulfenamide, N-ethyl-Nt- Butylbenzothiazol-2-sulfenamide, Nn-propyl-Nt-butylbenzothiazol-2-sulfenamide, N-isopropyl-Nt-butylbenzothiazol 2-sulfenamide, Nn-butyl-Nt-butylbenzothiazol-2-sulfenamide, N-isobutyl-Nt-butylbenzothiazol-2-sulfenamide N-sec-butyl-Nt-butylbenzothiazol-2-sulfenamide, N-methyl-N-isoamylbenzothiazol-2-sulfenamide, N-ethyl-N-isoamyl Benzothiazol -Sulfenamide, Nn-propyl-N-isoamylbenzothiazol-2-sulfenamide, N-isopropyl-N-isoamylbenzothiazol-2-sulfenamide, Nn-butyl -N-isoamylbenzothiazol-2-sulfenamide, N-isobutyl-N-isoamylbenzothiazol-2-sulfenamide, N-sec-butyl-N-isoamylbenzothiazol- 2-sulfenamide, N-methyl-N-tert-amylbenzothiazol-2-sulfenamide, N-ethyl-N-tert-amylbenzothiazol-2-sulfenamide, N- n-propyl-N-tert-amylbenzothiazol-2-sulfenamide, N-isopropyl-N-tert-amylbenzothiazol-2-sulfen N-butyl-N-tert-amylbenzothiazol-2-sulfenamide, N-isobutyl-N-tert-amylbenzothiazol-2-sulfenamide, N-sec- Butyl-N-tert-amylbenzothiazol-2-sulfenamide, N-methyl-N-tert-heptylbenzothiazol-2-sulfenamide, N-ethyl-N-tert-heptylbenzo Thiazol-2-sulfenamide, Nn-propyl-N-tert-heptylbenzothiazol-2-sulfenamide, N-isopropyl-N-tert-heptylbenzothiazol-2 -Sulfenamide, Nn-butyl-N-tert-heptylbenzothiazol-2-sulfenamide, N-isobutyl-N-tert-heptyl And rubenzothiazol-2-sulfenamide, N-sec-butyl-N-tert-heptylbenzothiazol-2-sulfenamide, and the like. These compounds can be used alone or in admixture of two or more (hereinafter, simply referred to as “at least one”).
Preferably, from the viewpoint of further adhesion performance, N-methyl-Nt-butylbenzothiazol-2-sulfenamide, N-ethyl-Nt-butylbenzothiazol-2-sulfenamide Fenamide, Nn-propyl-Nt-butylbenzothiazol-2-sulfenamide, N-isopropyl-Nt-butylbenzothiazol-2-sulfenamide, N-isobutyl -Nt-butylbenzothiazol-2-sulfenamide and N-sec-butyl-Nt-butylbenzothiazol-2-sulfenamide are preferable.
Among these, N-methyl-Nt-butylbenzothiazol-2-sulfenamide, N-ethyl-N are particularly preferred in that co-vulcanization is further enhanced and excellent adhesive performance is exhibited. It is desirable to use -t-butylbenzothiazol-2-sulfenamide and Ni-propyl-Nt-butylbenzothiazol-2-sulfenamide.
These compounds may be used alone or in combination. Also, general-purpose vulcanization accelerators such as N-tert-butyl-2-benzothiazolsulfenamide (TBBS), N-cyclohexyl-2-benzothiazolsulfenamide (CBS), dibenzothiazolyl disulfide (MBTS) It is also possible to use in combination.

The following method can be mentioned as a preferable manufacturing method of the sulfenamide compound represented by the general formula (I) of the present invention.
That is, N-chloroamine and bis (benzothiazol-2-yl) disulfide prepared in advance by the reaction of the corresponding amine and sodium hypochlorite are reacted in an appropriate solvent in the presence of an amine and a base. If an amine is used as the base, neutralize and return to the free amine, then subject to appropriate post-treatment such as filtration, washing with water, concentration and recrystallization according to the properties of the resulting reaction mixture. Sulfenamide is obtained.
Examples of the base used in this production method include raw material amine used in excess, tertiary amine such as triethylamine, alkali hydroxide, alkali carbonate, alkali bicarbonate, sodium alkoxide and the like. In particular, the reaction is carried out using excess raw material amine as a base or tertiary amine triethylamine, neutralizing the hydrochloride formed with sodium hydroxide, taking out the target product, and then removing the amine from the filtrate. A method of reuse is desirable.
As the solvent used in this production method, alcohol is desirable, and methanol is particularly desirable.

  For example, in N-ethyl-Nt-butylbenzothiazol-2-sulfenamide, an aqueous sodium hypochlorite solution was added dropwise to Nt-butylethylamine at 0 ° C. or lower and the oil layer was stirred for 2 hours. Was sorted. Bis (benzothiazol-2-yl) disulfide, Nt-butylethylamine and the oil layer described above were suspended in methanol and stirred under reflux for 2 hours. After cooling, the solution is neutralized with sodium hydroxide, filtered, washed with water, concentrated under reduced pressure, and recrystallized to obtain the target BEBS (white solid).

The content of these sulfenamide-based vulcanization accelerators is 0.1 to 10 parts by mass, preferably 0.5 to 5.0 parts by mass, and more preferably 0.1 to 100 parts by mass of the rubber component. It is desirable to be 8 to 2.5 parts by mass.
When the content of the vulcanization accelerator is less than 0.1 parts by mass, the vulcanization is not sufficiently performed. On the other hand, when it exceeds 10 parts by mass, bloom is a problem, which is not preferable.

Sulfur used in the present invention serves as a vulcanizing agent, and its content is 0.1 to 10 parts by mass, preferably 1.0 to 7.0 parts by mass, with respect to 100 parts by mass of the rubber component. More preferably, it is desirable to set it as 3.0-7.0 mass parts.
If the sulfur content is less than 0.1 parts by mass, vulcanization will not be achieved sufficiently. On the other hand, if it exceeds 10 parts by mass, the aging performance of the rubber will be unfavorable.

In addition to the rubber component, sulfur, and vulcanization accelerator, the rubber composition of the present invention can contain a filler that is usually used in a rubber composition for bead fillers, such as carbon black and silica. The inorganic filler can be contained.
The total content of these inorganic fillers is 20 parts by mass or more, preferably 30 to 150 parts by mass, more preferably in the range of 35 to 100 parts by mass with respect to 100 parts by mass of the rubber component. is there.

The carbon black to be used is not particularly limited, and any carbon black conventionally used as a reinforcing filler for rubber can be selected and used. Examples of carbon black include GPF, FEF, SRF, HAF, ISAF, and SAF. Preferably, the nitrogen adsorption specific surface area (N ₂ SA) of 30 to 150 m ² / g, and a dibutyl phthalate (DBP) oil absorption is carbon black 80~140cm ³ / 100g. By using carbon black, the effect of improving various physical properties is increased.

The silica that can be used is not particularly limited, and examples thereof include wet silica (hydrous silicic acid), dry silica (anhydrous silicic acid), calcium silicate, aluminum silicate, and the like. preferable. Moreover, it can use together with the said carbon black.
When silica is used as the filler, a silane coupling agent can be contained as desired. The silane coupling agent is not particularly limited, and known ones conventionally used in rubber compositions such as bis (3-triethoxysilylpropyl) polysulfide, γ-mercaptopropyltriethoxysilane, γ-amino Propyltriethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, N-β- (aminoethyl) -γ-aminopropyltrimethoxysilane, and the like can be used. The compounding quantity of the silane coupling agent used depending on necessity is normally selected in the range of 1 to 20% by mass with respect to silica. By setting the amount of the silane coupling agent within the above range, the effect as a coupling agent is sufficiently exhibited, and the rubber component is not gelled. From the viewpoint of the effect as a coupling agent and the prevention of gelation, the preferred amount of the silane coupling agent is in the range of 5 to 15% by mass.

The rubber composition of the present invention preferably contains a resin and its curing agent from the viewpoint of further improving the durability of the bead filler.
Examples of the resin that can be used include thermosetting resins such as phenol resins and melamine resins. Of these, phenol resins are particularly preferred.
The phenol resin is an oligomer or polymer obtained by condensing phenols and aldehydes. As phenols, lower alkylphenols such as phenol, cresols, xylenol and tert-butylphenol, higher phenols such as nonylphenol, cashew oil and lignin, and dihydric phenols such as resorcin and catechol are used. As aldehydes, formaldehyde is mainly used.
Examples of the phenol resin include phenol-formaldehyde resin, resorcin-formaldehyde resin, and cresol resin.
As the phenol resin, a natural resin-modified phenol resin, an oil-modified phenol resin, or the like can be used in addition to a 100% phenol resin.

Moreover, it is preferable to use the novolak-type resin which is 2 step resin hardened using a hardening | curing agent for resin, such as the said phenol resin.
Examples of the curing agent include methylene donors such as hexamethylenetetramine and hexamethoxymethylmelamine. These combinations can be freely selected, and a plurality of resins and their curing agents may be selected. Further, a resin in which a curing agent is internally added may be used.

In particular, as a preferred resin and its curing agent, it is desirable to include a phenol resin and a methylene donor.
The phenol resin used in the present invention can make the rubber more elastic while suppressing a decrease in the fracture resistance of the rubber. Specific examples of the phenol resin that can be used include novolac type phenol resins, novolac type cresol resins, novolac type xylenol resins, novolac type resorcinol resins, and resins obtained by modifying these resins with oil. Therefore, it is preferable to use at least one of these resins.
Examples of the oil used for modifying the phenol resin include rosin oil, tall oil, cashew oil, linoleic acid, oleic acid, and linolenic acid, and at least one of these oils is preferably used.

  The content of the resin such as phenol resin is 1 to 40 parts by mass, preferably 5 to 20 parts by mass with respect to 100 parts by mass of the rubber component. If the content of the resin such as the phenol resin is less than 1 part by mass, the effect of increasing the elasticity of the rubber composition may not be sufficiently exhibited. On the other hand, if the content exceeds 40 parts by mass, Flexibility may be impaired.

  The methylene donor used in the present invention acts as a curing agent for the above-mentioned phenolic resin. Acetaldehyde ammonia, (alpha) -polyoxymethylene, paraformaldehyde, etc. are mentioned, It is preferable to use at least 1 sort (s) among these. Among these, hexamethylenetetramine and hexamethoxymethylmelamine are preferable from the viewpoint that a rubber composition having a high curing rate and a higher elasticity can be obtained.

  The content of the curing agent such as methylene donor is usually 5 to 80% by mass, preferably 30 to 60% by mass in 100% by mass of the total amount of the phenol resin and methylene donor (total amount of resin and its curing agent). Is the amount. If the content of the curing agent such as a methylene donor is less than 5% by mass, the curing of the phenol resin or the like may not sufficiently proceed. On the other hand, if it exceeds 80% by mass, the rubber crosslinking system is adversely affected. There is a case.

  In the rubber composition for bead filler of the present invention, various chemicals usually used in the rubber industry, for example, process oil, anti-aging agent, anti-scorch agent, zinc, are used as long as the object of the present invention is not impaired. Hana, stearic acid and the like can be contained.

The rubber composition for bead filler of the present invention is obtained by kneading using a kneader such as a roll or an internal mixer, and there is no particular limitation on its use, but it is particularly suitable for use as a bead filler. Is done.
The tire of the present invention is produced by an ordinary method using the rubber composition for bead fillers of the present invention. That is, if necessary, the bead filler rubber composition of the present invention containing various chemicals as described above is extruded into a bead filler at an unvulcanized stage, and is applied by a normal method on a tire molding machine. The green tire is formed by attaching. This green tire is heated and pressurized in a vulcanizer to obtain the desired tire.

Further, in the run flat tire of the present invention, the rubber composition containing the sulfenamide vulcanization accelerator represented by the above general formula (I) using the rubber composition for bead filler of the present invention as a bead filler. The object run-flat tire can be manufactured in the same manner as described above by using the object for the side reinforcing layer.
The run-flat tire of the present invention uses the above rubber composition for bead filler as a bead filler, and side-reinforces the rubber composition containing the sulfenamide-based vulcanization accelerator represented by the above general formula (I). Since the run-flat tire is used for the layer, the rubber composition used for the side reinforcing layer is the one containing the sulfenamide-based vulcanization accelerator represented by the general formula (I). Rubber components other than the vulcanization accelerator, fillers, and other compounding agents are not particularly limited, and rubber components and fillers used for known side reinforcing layers are used. Further, in the rubber composition containing the sulfenamide vulcanization accelerator represented by the above general formula (I) when used for the side reinforcing layer, the content of the sulfenamide vulcanization accelerator is a bead. Similar to the rubber composition for filler, 0.1 to 10 parts by weight, preferably 0.5 to 5.0 parts by weight, more preferably 0.8 to 100 parts by weight of the rubber component for the side reinforcing layer. It is desirable to set it to -2.5 mass parts. Furthermore, the rubber composition used for the side reinforcing layer may contain the above-described resin and its curing agent from the viewpoint of further improving the durability of the side reinforcing layer.

Next, embodiments of the tire of the present invention will be described with reference to the accompanying drawings.
FIG. 1 is a partial cross-sectional view of the left half showing an example when the tire of the present invention is applied to a pneumatic tire. The pneumatic tire A includes a bead core 10, a carcass layer 11, a side rubber layer 12, and a tread rubber. The layer 13, the belt layer 14, the inner liner 15, and the bead filler 16 are included, and the bead filler 16 is interposed between the tire side rubber layer 12 and the inner liner 15. Reference numeral 17 denotes a rim, and 18 denotes a folded portion of the carcass ply.
In the pneumatic tire A of this form, for example, the bead filler 16 is replaced with the rubber composition of the present invention, that is, the rubber component, sulfur, and the sulfenamide-based vulcanization accelerator represented by the above general formula (I). By adjusting the vulcanization speed of these members in consideration of the vulcanization characteristics of the inner liner and ply coating rubber which are members adjacent to the bead filler 16 A tire with excellent bead filler durability can be obtained by sufficiently co-curing the bead filler 16 and adjacent members (inner liner, ply coating rubber) and strengthening their adhesion. It can be obtained.

FIG. 2 is a partial cross-sectional view of the left half showing an example when the tire of the present invention is applied to a run flat tire. The run flat tire B includes a bead core 20, a carcass layer 21, a side rubber layer 22, and a tread rubber. A structure having a layer 23, a belt layer 24, an inner liner 25, and a bead filler 26, and a side reinforcing layer (side reinforcing rubber) 27 having a substantially crescent-shaped cross section interposed between the tire side rubber layer 22 and the inner liner 25. It will be. Reference numeral 28 denotes a shoulder area.
In the run-flat tire of this form, for example, the bead filler 26 includes the rubber composition of the present invention, that is, the rubber component, sulfur, and the sulfenamide-based vulcanization accelerator represented by the above general formula (I). By using the rubber composition containing the sulfenamide-based vulcanization accelerator represented by the above general formula (I) for the side reinforcing layer 27, the bead filler rubber composition is used. In consideration of the vulcanization characteristics of the inner liner and ply coating rubber which are members adjacent to the filler 26 and the side reinforcing layer 27, the vulcanization speed of these members can be adjusted, and the bead filler 26 and the side reinforcing layer are adjusted. 27 and the adjacent members (inner liner, ply coating rubber) are sufficiently co-cured, and their adhesion is strengthened. It is possible to obtain a run-flat tire having excellent flat durability, in particular, in the run-flat running, durability is greatly improved, and it can be extended considerably the travel distance.

Next, a production example of a vulcanization accelerator used in the present invention, a rubber composition for bead filler of the present invention, a pneumatic tire using this rubber composition as a bead filler, and an implementation of a run flat tire The present invention is further described in detail based on examples and comparative examples, but the present invention is not limited to these production examples and examples.
The octanol / water partition coefficient (log P) of the vulcanization accelerator obtained in each of the following production examples was measured by a high performance liquid chromatography method according to JIS Z 7260-117 (2006). A high performance liquid chromatography manufactured by Shimadzu Corporation was used.

[Production Example 1: Synthesis of N-ethyl-Nt-butylbenzothiazol-2-sulfenamide]
To 16.4 g (0.162 mol) of Nt-butylethylamine, 148 g of a 12% sodium hypochlorite aqueous solution was added dropwise at 0 ° C. or less, and after stirring for 2 hours, the oil layer was separated. Bis (benzothiazol-2-yl) disulfide (39.8 g, 0.120 mol), Nt-butylethylamine (24.3 g, 0.240 mmol) and the aforementioned oil layer were suspended in methanol (120 ml) and refluxed. Stir for 2 hours. After cooling, the solution was neutralized with 6.6 g (0.166 mol) of sodium hydroxide, filtered, washed with water, concentrated under reduced pressure, and recrystallized to obtain the target N-ethyl-Nt-butylbenzothiazol. -2-sulfenamide was obtained as 41.9 g (yield 66%) of a white solid (melting point 60-61 ° C.).
The spectrum data of the obtained N-ethyl-Nt-butylbenzothiazol-2-sulfenamide is shown below.
¹ H-NMR (400 MHz, CDCl ₃ ) δ = 1.29 (t, 3H, J = 7.1 Hz, CH ₃ (ethyl)), 1.34 (s, 9H, CH ₃ (t-butyl)), 2.9-3.4 (br-d, CH ₂ ), 7.23 (1H, m), 7.37 (1H, m), 7.75 (1H, m), 7.78 (1H, m ): ¹³ C-NMR (100 MHz, CDCl ₃ ) δ = 15.12, 28.06, 47.08, 60.41, 120.70, 121.26, 123.23, 125.64, 134.75, 154.93, 182.63: mass spectrometry (EI, 70 eV): m / z; 251 (M ⁺ —CH ₄ ), 167 (M ⁺ —C ₆ H ₁₄ N), 100 (M ⁺ —C ₇ H _{5) NS 2): IR (KBr,} cm -1): 3061,2975,2932,2868,1461,1429,13 3,1366,1352,1309,1273,1238,1198,1103,1022,1011,936,895,756,727.
The N-ethyl-Nt-butylbenzothiazol-2-sulfenamide had an octanol / water partition coefficient (log P) of 4.9.

[Production Example 2: Synthesis of N-methyl-Nt-butylbenzothiazol-2-sulfenamide]
N-methyl-Nt-butylbenzothiazol-2 was carried out in the same manner as in Example 1 except that 14.1 g (0.162 mol) of Nt-butylmethylamine was used instead of Nt-butylethylamine. -Sulfenamide was obtained as 46.8 g (82% yield) of a white solid (melting point 56-58 ° C.).
¹ H-NMR (400 MHz, CDCl ₃ ) δ = 1.32 (9H, s, CH ₃ (t-butyl)), 3.02 (3H, s, CH ₃ (methyl)), 7.24 (1H, m), 7.38 (1H, m), 7.77 (1H, m), 7.79 (1H, m): ¹³ C-NMR (100 MHz, CDCl ₃ ) δ = 27.3, 41.9, 59.2, 120.9, 121.4, 123.3, 125.7, 135.0, 155.5, 180.8: mass spectrometry (EI, 70 eV) m / z; 252 (M ⁺ ), 237 _{^{(M + -CH 3), 223}} (M + -C 2 H 6), 195 (M + -C 4 H 9), 167 (M + -C 5 H 12 N), 86 (M + -C 7 H ₄ NS ₂ ).
The N-methyl-Nt-butylbenzothiazol-2-sulfenamide had an octanol / water partition coefficient (log P) of 4.5.

[Production Example 3: Synthesis of Nn-propyl-Nt-butylbenzothiazol-2-sulfenamide]
The same procedure as in Example 1 was carried out using 18.7 g (0.162 mol) of Nn-propyl-t-butylamine instead of Nt-butylethylamine, and Nn-propyl-Nt-butylbenzothia. Sol-2-sulfenamide was obtained as a white solid (melting point 50-52 ° C.).
¹ H-NMR (400 MHz, CDCl ₃ ) δ: 0.92 (t, J = 7.3 Hz, 3H), 1.34 (s, 9H), 1.75 (br, 2H), 3.03 (brd , 2H), 7.24 (t, J = 7.0 Hz, 1H), 7.38 (t, J = 7.0 Hz, 1H), 7.77 (d, J = 7.5 Hz, 1H), 7 79 (d, J = 7.5 Hz, 1H).
¹³ C-NMR (100 MHz, CDCl ₃ ) δ: 11.7, 23.0, 28.1, 55.3, 60.4, 120.7, 121.3, 123.3, 125.7, 134. 7, 154.8, 181.3.
This Nn-propyl-Nt-butylbenzothiazol-2-sulfenamide had an octanol / water partition coefficient (log P) of 5.3.

[Production Example 4: Synthesis of Ni-propyl-Nt-butylbenzothiazol-2-sulfenamide]
The same procedure as in Example 1 was carried out using 18.7 g (0.162 mol) of Ni-propyl-t-butylamine instead of Nt-butylethylamine, and Ni-propyl-Nt-butylbenzothia. Zol-2-sulfenamide was obtained as a white solid (melting point 68-70 ° C.).
¹ H-NMR (400 MHz, CDCl ₃ ) δ: 1.20-1.25 (dd, (1.22 ppm: J = 6.4 Hz, 1.23 ppm: J = 6.4 Hz) 6H), 1.37 ( s, 9H), 3.78 (m, J = 6.3 Hz, 1H), 7.23 (t, J = 7.0 Hz, 1H), 7.38 (t, J = 7.0 Hz, 1H), 7.77 (d, J = 7.5 Hz, 1H), 7.79 (d, J = 7.5 Hz, 1H).
¹³ C-NMR (100 MHz, CDCl ₃ ) δ: 22.3, 23.9, 29.1, 50.6, 61.4, 120.6, 121.2, 123.2, 125.6, 134. 5, 154.5, 183.3.
This Ni-propyl-Nt-butylbenzothiazol-2-sulfenamide had an octanol / water partition coefficient (log P) of 5.1.

[Production Example 5: Synthesis of N, N-di-i-propylbenzothiazol-2-sulfenamide]
The same procedure as in Example 1 was carried out using 16.4 g (0.162 mol) of N-di-i-propylamine instead of Nt-butylethylamine, and N, N-di-i-propylbenzothiazol. 2-Sulfenamide was obtained as a white solid (melting point 57-59 ° C.).
¹ H-NMR (400 MHz, CDCl ₃ ) δ: 1.26 (d, J = 6.5 Hz, 12H), 3.49 (dq, J = 6.5 Hz, 2H), 7.24 (t, J = 7.0 Hz, 1H), 7.37 (t, J = 7.0 Hz, 1H), 7.75 (d, J = 8.6 Hz, 1H), 7.79 (d, J = 8.6 Hz, 1H) ).
¹³ C-NMR (100 MHz, CDCl ₃ ) δ: 21.7, 22.5, 55.7, 120.8, 121.3, 123.4, 125.7, 134.7, 155.1, 182. 2.
Mass spectrometry (EI, 70 eV), m / z 266 (M ⁺ ), 251 (M ⁺ −15), 218 (M ⁺ −48), 209 (M ⁺ −57), 182 (M ⁺ −84), 167 ( M ^<+>- 99), 148 (M ^<+ > ^- 118), 100 (M ^<+ > ^- 166: base).

[Production Example 6: Synthesis of Nn-butyl-Nt-butylbenzothiazol-2-sulfenamide]
The same procedure as in Example 1 was carried out using 20.9 g (0.162 mol) of Nt-butyl-n-butylamine instead of Nt-butylethylamine, and Nn-butyl-Nt-butylbenzothia. Sol-2-sulfenamide was obtained as 42.4 g (yield 60%) of a white solid (melting point 55-56 ° C.).
¹ H-NMR (400 MHz, CDCl ₃ ) δ = 0.89 (3H, t, J = 7.32 Hz, CH ₃ (n-Bu)), 1.2-1.4 (s + m, 11H, CH ₃ ( t-butyl) + CH ₂ (n-butyl)), 1.70 (br.s, 2H, CH ₂ ), 2.9-3.2 (br.d, 2H, N—CH ₂ ), 7.23 (1H, m), 7.37 (1H, m), 7.75 (1H, m), 7.78 (1H, m); ¹³ C-NMR (100 MHz, CDCl ₃ ) δ: 14.0, 20 .4, 27.9, 31.8, 53.0, 60.3, 120.6, 121.1, 123.1, 125.5, 134.6, 154.8, 181.2; mass spectrometry ( EI, 70 eV), m / z 294 (M ⁺ ), 279 (M ⁺ —CH ₃ ), 237 (M ⁺ —C ₄ H ₉ ), 167 (M ⁺ —C ₈ H ₁₈ N), 1 28 (M ⁺ -C ₇ H ₄ NS ₂ ): IR (neat): 1707 cm ⁻¹ , 3302 cm ⁻¹
The Nn-butyl-Nt-butylbenzothiazol-2-sulfenamide had an octanol / water partition coefficient (log P) of 5.8.

[Examples 1-6 and Comparative Examples 1-3]
<Preparation of bead filler rubber and ply coating rubber>
After kneading with a Banbury mixer according to a conventional method, the respective unvulcanized rubbers were obtained according to the composition shown in Table 1 below. Using these unvulcanized rubbers, vulcanization characteristics (TO.1 INDEX, TO.9 INDEX) were evaluated by the following evaluation method.
These results are shown in Table 1 below.

<Measurement of vulcanization characteristics>
It measured at 160 degreeC based on JISK3200-2: 2001 using the JSR Trading company made curast meter W type tester. Comparative example 1 was used as a reference (100) and evaluated by index display. Higher values indicate better vulcanization characteristics.

<Production of each sample tire, conforming to Fig. 1>
Each prototype tire (tire size 245 / 40ZR18) was produced by a conventional method using each bead filler and ply coating rubber (common) shown in Table 1 below. For each tire, a bead filler-ply peel test, a running distance of the durable drum, and the presence or absence of interface peeling of the ply coating rubber part during running by running the durable drum were determined by the following evaluation methods. Each evaluation of the bead filler-ply peel test and the durability drum travel distance was evaluated by index display with Comparative Example 1 as a reference (100). It shows that it is excellent in durability of a bead filler, so that a numerical value is high.
These results are shown in Table 1 below.

<Peel test between bead filler and ply>
A tire side portion including a bead filler is cut out with a width of 30 mm and a length of 100 mm. A notch is made between the ply coating rubber and the bead filler layer, the sample ply and the reinforcing rubber are once gripped by the chuck of an autograph type tester, and peeled in the length direction of the rectangle at a pulling speed of 50 mm / min. Then, the tensile force at that time was measured.

<Measurement of endurance drum travel distance>
Each prototype tire (tire size 255 / 55R18) is assembled with a rim at normal pressure (used rim 8.5 JJ × 18), filled with 0 kPa of internal pressure, allowed to stand at room temperature of 38 ° C. for 24 hours, and then the valve core is removed. The drum running test was performed under the conditions of an internal pressure of atmospheric pressure, a load of 6.57 kN (670 kg), a speed of 80 km / h, and a room temperature of 38 ° C. The travel distance at the time of failure occurrence was defined as the drum travel distance. It shows that it is excellent in durability, so that a numerical value is high.

<Evaluation method of presence / absence of interface peeling>
The presence or absence of interface peeling in the ply coating rubber part of each tire after running the drum was observed.

[Examples 7 to 12 and Comparative Examples 4 to 6]
<Preparation of bead filler rubber, side reinforcing rubber, ply coating rubber>
After kneading with a Banbury mixer according to a conventional method according to the composition shown in Table 2 below, each unvulcanized rubber was obtained. Using these unvulcanized rubbers, the vulcanization characteristics (TO.1 INDEX, TO.9 INDEX) were evaluated by the above evaluation method. In Table 2, it evaluated by the index display by making Comparative Example 4 into a reference | standard (100).
These results are shown in Table 2 below.

<Production of each sample tire, based on Fig. 2>
Each prototype tire (tire size 245 / 40ZR18) was produced by a conventional method using each bead filler rubber, side reinforcing rubber, and ply coating rubber (common) shown in Table 2 below. With respect to each run flat tire, the following evaluation methods were used to determine whether or not the peeling test between the reinforcing rubber and the ply, the run flat (RF) drum travel distance, and the occurrence of interfacial peeling at the ply coating rubber portion during running by run flat running. Each evaluation of the peel test between the reinforced rubber and the ply and the run flat (RF) drum travel distance was evaluated by index display with Comparative Example 4 as a reference (100). Higher values indicate better run flat durability.
These results are shown in Table 2 below.

<Peeling test between reinforced rubber and ply>
A tire side portion including the reinforcing rubber is cut out with a width of 30 mm and a length of 100 mm. A notch is made between the ply coating rubber and the reinforcing rubber layer, and the sample ply and the reinforcing rubber are once gripped by the chuck of the autograph type tester and peeled in the length direction of the rectangle at a pulling speed of 50 mm / min. Then, the tensile force at that time was measured.

<Measurement of RF drum travel distance>
Each prototype tire (tire size 255 / 55R18) is assembled with a rim at normal pressure, filled with an internal pressure of 230 kPa, and allowed to stand at room temperature of 38 ° C. for 24 hours. Then, the valve core is removed and the internal pressure is set to atmospheric pressure. A drum running test was performed under the conditions of a load of 5.19 kN (530 kg), a speed of 80 km / h, and a room temperature of 38 ° C. The travel distance at the time of failure occurrence was defined as the run-flat drum travel distance. The higher the value, the better the run flat durability.

<Evaluation method of presence / absence of interface peeling>
The presence or absence of interface peeling in the ply coating rubber part of each tire after running the drum was observed.

* 1 to * 10 in Table 1 and Table 2 are as follows.
* 1: N, N′-dicyclohexyl-2-benzothiazylsulfenamide (Ouchi Shinsei Chemical Co., Ltd., trade name: Noxeller DZ)
* 2: N-cyclohexyl-2-benzothiazylsulfenamide (Ouchi Shinsei Chemical Co., Ltd., trade name: Noxeller CZ)
* 3: Nt-butylbenzothiazole-2-sulfenamide (Ouchi Shinsei Chemical Co., Ltd., trade name: Noxeller NS)
* 4: Di-2-benzothiazolyl disulfide (Ouchi Shinsei Chemical Co., Ltd., trade name: Noxeller DM)
* 5: N-methyl-Nt-butylbenzothiazol-2-sulfenamide * 6: N-ethyl-Nt-butylbenzothiazol-2-sulfenamide * 7: N -N-propyl-Nt-butylbenzothiazol-2-sulfenamide * 8: Ni-propyl-Nt-butylbenzothiazol-2-sulfenamide * 9: N , N-di-i-propylbenzothiazol-2-sulfenamide * 10: Nn-butyl-Nt-butylbenzothiazol-2-sulfenamide

  As is clear from the evaluation results of the tires using the rubber composition for bead filler and the rubber composition for bead filler in Table 1 above, Examples 1 to 6 which are the scope of the present invention are outside the scope of the present invention. As compared with Comparative Examples 1 to 3, it was found that the vulcanization characteristics were excellent and the durability of the bead filler was excellent from the evaluation results of the peeling effectiveness, the drum travel distance, and the presence or absence of interfacial peeling.

  Evaluation results of run-flat tires using the rubber composition for bead filler in Table 2 above and the rubber composition containing the sulfenamide-based vulcanization accelerator represented by the general formula (I) in the side reinforcing layer As can be seen from the above, Examples 7 to 12, which are the scope of the present invention, are superior in vulcanization characteristics as compared with Comparative Examples 4 to 6 which are outside the scope of the present invention, and also have a peeling effect, RF drum travel distance and interface. From the evaluation results of the presence or absence of peeling, it was found that the bead filler and the side reinforcing layer were excellent in durability and run flat durability.

  The present invention can be suitably applied to pneumatic tires such as passenger cars, run flat tires, and the like.

It is a partial sectional view of the left half showing an example of an embodiment of a tire of the present invention. It is a fragmentary sectional view of the left half which shows the other examples of the embodiment of the tire of the present invention.

A Pneumatic tire 10 Bead core 11 Carcass layer 12 Side rubber layer 13 Tread rubber layer 14 Belt layer 15 Inner liner 16 Bead filler

Claims (13)

A rubber composition for bead filler, comprising a rubber component, sulfur, and a sulfenamide vulcanization accelerator represented by the following general formula (I).

  The rubber composition for bead filler according to claim 1, comprising 0.1 to 10 parts by mass of the sulfenamide vulcanization accelerator represented by the general formula (I) with respect to 100 parts by mass of the rubber component. .   The rubber composition for bead filler according to claim 1, comprising 0.1 to 10 parts by mass of sulfur with respect to 100 parts by mass of the rubber component.   Claims comprising 0.1 to 10 parts by mass of sulfur and 0.1 to 10 parts by mass of a sulfenamide vulcanization accelerator represented by the above general formula (I) with respect to 100 parts by mass of the rubber component. Item 2. A rubber composition for bead filler according to Item 1. The rubber composition according to claim 1, wherein the branched alkyl group in R ¹ and R ² in the general formula (I) in the rubber composition has a branch at the α-position. 2. The rubber composition according to claim 1, wherein R ¹ in the general formula (I) in the rubber composition is a tert-butyl group and n = 0. R ¹ in the general formula (I) in the rubber composition is a tert-butyl group, R ² is a linear alkyl group having 1 to 6 carbon atoms or a branched alkyl group having 3 to 6 carbon atoms, The rubber composition according to claim 1, wherein R ^{3 to} R ⁶ are hydrogen atoms. R ¹ in the general formula (I) in the rubber composition is a tert-butyl group, n = 0, and R ² is a linear alkyl group having 1 to 6 carbon atoms or a carbon atom having 3 to 6 carbon atoms. The rubber composition according to claim 1, which is a branched alkyl group, and R ^{3 to} R ⁶ are hydrogen atoms. Wherein R ¹ in the general formula (I) in the rubber composition is a tert- butyl group, a n = 0, R ² is a methyl group, an ethyl group, an n- propyl group, R ³ to R ⁶ The rubber composition according to claim 1, wherein is a hydrogen atom. R ¹ in the general formula (I) in the rubber composition is a tert-butyl group, n = 0, R ² is an ethyl group, and R ^{3 to} R ⁶ are hydrogen atoms. 2. The rubber composition according to 1.   The rubber composition for bead filler according to any one of claims 1 to 10, wherein the rubber component contains at least one of natural rubber and polyisoprene rubber.   A tire comprising the bead filler rubber composition according to any one of claims 1 to 11 as a bead filler.   A rubber composition comprising the rubber composition for bead filler according to any one of claims 1 to 11 as a bead filler and containing a sulfenamide-based vulcanization accelerator represented by the general formula (I). A run-flat tire characterized by using an object as a side reinforcing layer.

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