JP2019131646A - Tire rubber composition and tire - Google Patents

Abstract

To provide a tire rubber composition, which is a rubber composition containing silica, the composition having excellent fuel economy and fracture strength and also satisfying both of moldability (ensured molding time) and a vulcanization rate (shortened vulcanization time), and a tire having a tire member composed of the rubber composition.SOLUTION: A tire rubber composition contains a rubber component, silica, a compound containing a predetermined bond unit I and a predetermined bond unit II, and aminoguanidine weak acid salt.SELECTED DRAWING: None

Description

  The present invention relates to a tire rubber composition and a tire having a tire member composed of the tire rubber composition.

  In recent years, the characteristics required for automobile tires have been diversified. In particular, the demand for low fuel consumption has been increasing for the purpose of saving fuel consumption of automobiles due to social demands for energy saving.

  Technology for blending silica and the like into tire rubber compositions is known to improve fuel economy, but the problem of vulcanization speed reduction (vulcanization delay) and silica dispersibility due to silica blending is known. Occurs.

  In order to suppress the vulcanization delay, it is known to add a predetermined amine addition salt or the like (Patent Document 1). It is also known to add a predetermined silane coupling agent having a mercapto group in order to improve fuel economy and the like.

JP 2001-139727 A

  However, the addition of an amine addition salt or the like of Patent Document 1 or the addition of a predetermined silane coupling agent having a mercapto group has a problem that the scorch time is shortened and molding processability is lowered.

  The present invention relates to a rubber composition for tires that is excellent in fuel efficiency and fracture strength, and that has both moldability (ensuring molding time) and vulcanization speed (shortening vulcanization time) with respect to a rubber composition containing silica. It is an object of the present invention to provide a tire and to provide a tire having a tire member composed of the rubber composition.

  As a result of intensive studies, the present inventor has found that the above problem can be solved by further adding an aminoguanidine weak acid salt to a rubber composition containing silica and a predetermined silane coupling agent having a mercapto group. The present invention was completed through repeated studies.

（式中、Ｒ¹は水素、ハロゲン、分岐もしくは非分岐の炭素数１〜３０のアルキル基、分岐もしくは非分岐の炭素数２〜３０のアルケニル基、分岐もしくは非分岐の炭素数２〜３０のアルキニル基、または該アルキル基の末端の水素が水酸基もしくはカルボキシル基で置換されたものを示す。Ｒ²は分岐もしくは非分岐の炭素数１〜３０のアルキレン基、分岐もしくは非分岐の炭素数２〜３０のアルケニレン基、または分岐もしくは非分岐の炭素数２〜３０のアルキニレン基を示す。Ｒ¹とＲ²とで環構造を形成してもよい。）
［２］アミノグアニジン弱酸塩が、重炭酸アミノグアニジンおよびアミノグアニジンリン酸塩からなる群から選択される少なくとも一つである、上記［１］記載のタイヤ用ゴム組成物、
［３］アミノグアニジン弱酸塩の含有量が、ゴム成分１００質量部に対し、０．０１〜１０質量部である、上記［１］または［２］記載のタイヤ用ゴム組成物、
［４］可塑剤３０質量部以上をさらに含み、該可塑剤のうち樹脂の含有量が５質量部以上である、上記［１］〜［３］のいずれかに記載のタイヤ用ゴム組成物、
［５］ゴム成分が、スチレンブタジエンゴムを５０質量％以上含むゴム成分である、上記［１］〜［４］のいずれかに記載のタイヤ用ゴム組成物、
［６］シリカの含有量が、ゴム成分１００質量部に対し、８０質量部以上である、上記［１］〜［５］のいずれかに記載のタイヤ用ゴム組成物、
［７］上記［１］〜［６］のいずれかに記載のタイヤ用ゴム組成物から構成されたタイヤ部材を有するタイヤ、
に関する。 That is, the present invention
[1] a rubber component;
Silica,
A compound comprising a binding unit I represented by the following formula (1) and a binding unit II represented by the following formula (2);
A rubber composition for tires comprising aminoguanidine weak acid salt,

Wherein R ¹ is hydrogen, halogen, branched or unbranched C 1-30 alkyl group, branched or unbranched C 2-30 alkenyl group, branched or unbranched C 2-30 An alkynyl group, or a group in which hydrogen at the terminal of the alkyl group is substituted with a hydroxyl group or a carboxyl group, R ² represents a branched or unbranched alkylene group having 1 to 30 carbon atoms, a branched or unbranched carbon number of 2 30 represents an alkenylene group or a branched or unbranched alkynylene group having 2 to 30 carbon atoms, and R ¹ and R ² may form a ring structure.)
[2] The rubber composition for tires according to the above [1], wherein the aminoguanidine weak acid salt is at least one selected from the group consisting of aminoguanidine bicarbonate and aminoguanidine phosphate,
[3] The rubber composition for tire according to the above [1] or [2], wherein the content of the aminoguanidine weak acid salt is 0.01 to 10 parts by mass with respect to 100 parts by mass of the rubber component.
[4] The rubber composition for tires according to any one of [1] to [3], further including 30 parts by mass or more of a plasticizer, wherein the resin content of the plasticizer is 5 parts by mass or more.
[5] The rubber composition for tires according to any one of the above [1] to [4], wherein the rubber component is a rubber component containing 50% by mass or more of styrene butadiene rubber,
[6] The rubber composition for tires according to any one of the above [1] to [5], wherein the silica content is 80 parts by mass or more with respect to 100 parts by mass of the rubber component.
[7] A tire having a tire member composed of the rubber composition for tires according to any one of [1] to [6],
About.

  According to the present invention, there is provided a rubber composition for a tire that is excellent in fuel efficiency and breaking strength, and further has both moldability (ensuring molding time) and vulcanization speed (shortening vulcanization time), And the tire which has a tire member comprised from this rubber composition can be provided.

  One embodiment of the present invention comprises a rubber component, silica, a compound containing a bond unit I represented by the above formula (1) and a bond unit II represented by the above formula (2), and an aminoguanidine weak acid salt. A tire rubber composition comprising the tire composition.

  Other this embodiment is a tire which has a tire member comprised from the said rubber composition for tires.

  Although not intended to be bound by theory, the following may be considered as a mechanism for obtaining a predetermined effect in the present embodiment. In other words, silica can improve fuel economy and breaking strength, but on the other hand, the silanol group adsorbs the vulcanization accelerator, so that the vulcanization time tends to be too long. Moreover, the compound containing the bond unit I shown by the said Formula (1) and the bond unit II shown by the said Formula (2) is known as a silane coupling agent which has a mercapto group, By adding this, Although fuel economy and the like can be improved, on the other hand, the scorch time tends to be short, and the moldability tends to be reduced. However, when aminoguanidine weak acid salt (carbonate, phosphate) is added, increase in vulcanization time can be suppressed even when silica is blended, and when the prescribed silane coupling agent is blended However, aminoguanidine supplements the fatty acid and thiol moiety to reduce scorch time (rubber burn), resulting in low fuel consumption, breaking strength, molding processability (ensuring molding time), vulcanization speed ( The shortening of vulcanization time is thought to improve in a well-balanced manner. In addition, aminoguanidine not only helps the dispersion of the silica due to its strong polarity, but also helps the hydrolysis reaction of the coupling agent, resulting in a higher reactivity between the silica and the polymer, through these, It is presumed that improvement in dispersibility of silica is achieved and low fuel consumption is realized.

<Rubber component>
In the present embodiment, the rubber component is not particularly limited, and any of those conventionally used in the tire industry can be suitably used. Examples of the rubber component include isoprene-based rubbers including natural rubber (NR) and polyisoprene rubber (IR), butadiene rubber (BR), styrene butadiene rubber (SBR), styrene isoprene rubber (SIR), styrene isoprene butadiene rubber ( SIBR), diene rubbers such as chloroprene rubber (CR), acrylonitrile butadiene rubber (NBR), butyl rubber (IIR), brominated butyl rubber (Br-IIR), chlorinated butyl rubber (Cl-IIR) and fluorinated butyl rubber (F) Butyl rubber such as halogenated butyl rubber containing -IIR). These rubber components may be used alone or in combination of two or more. Especially, it is preferable that it contains NR, SBR, BR from the reason that the effect of this embodiment can be exhibited more favorably, and it is more preferable that it consists only of NR, SBR, BR.

(Natural rubber)
NR is not particularly limited. For example, SIR20, RSS # 3, TSR20, etc., which are common in the tire industry (non-modified NR) can be used, epoxidized natural rubber (ENR), hydrogenated Modified natural rubbers such as natural rubber (HNR), grafted natural rubber, deproteinized natural rubber (DPNR), and highly purified natural rubber can also be used.

  In the case of containing NR, the content in the rubber component is preferably 1% by mass or more, more preferably 5% by mass or more, and more preferably 7% by mass or more from the viewpoints of moldability, reinforcement, and fuel efficiency. Preferably, 10 mass% or more is more preferable. Further, from the viewpoint of low fuel consumption, it is preferably 35% by mass or less, more preferably 30% by mass or less, more preferably 28% by mass or less, and further preferably 25% by mass or less.

(Styrene butadiene rubber)
The SBR is not particularly limited. For example, unmodified emulsion polymerized styrene butadiene rubber (E-SBR), solution polymerized styrene butadiene rubber (S-SBR), and modified emulsion polymerized styrene butadiene rubber (modified E-SBR) obtained by modifying them. And modified SBR such as modified solution polymerized styrene butadiene rubber (modified S-SBR). Examples of the modified SBR include modified SBR having a terminal and / or main chain modified, modified SBR coupled with tin, a silicon compound, or the like (condensate, one having a branched structure, or the like). The SBR includes an oil-extended type in which flexibility is adjusted by adding an extending oil, and a non-oil-extended type in which no extending oil is added, either of which can be used. For example, those manufactured by JSR Corporation, those manufactured by Asahi Kasei Chemicals Corporation, those manufactured by Nippon Zeon Co., Ltd. can be used.

The styrene content of SBR is preferably 15.0 mass% to 40.0 mass%. From the viewpoint of rubber strength and grip performance, the styrene content is preferably 20.0% by mass or more, more preferably 25.0% by mass or more, further preferably 30.0% by mass or more, and further preferably 35.0% by mass or more. preferable. Moreover, the styrene content of SBR is preferably 39.0% by mass or less from the viewpoint of low fuel consumption. The styrene content of SBR is a value calculated by ¹ H-NMR measurement.

  The SBR vinyl content (1,2-bonded butadiene unit amount) is preferably 10.0 to 30.0%. The vinyl content is preferably 13.0% or more and more preferably 15.0% or more from the viewpoint of rubber strength and grip performance. The vinyl content is preferably 25.0% or less, more preferably 20.0% or less, from the viewpoint of low fuel consumption. The vinyl content of SBR is a value measured by infrared absorption spectrum analysis.

  The content in the rubber component in the case of containing SBR is preferably 35% by mass or more, more preferably 40% by mass or more, and more preferably 45% by mass or more from the reason that the effect of the present embodiment can be exhibited more satisfactorily. Preferably, 50 mass% or more is more preferable. Moreover, 95 mass% or less is preferable, as for content of SBR, 90 mass% or less is preferable, 85 mass% or less is more preferable, and 80 mass% or less is further more preferable. When oil-extended SBR is used as SBR, the content of SBR itself as a solid content contained in the oil-extended SBR is defined as the content of SBR in the rubber component.

(Butadiene rubber)
The BR is not particularly limited, and any of those usually used in this field can be suitably used. For example, high cis-1,4-polybutadiene rubber (high cis BR), rare earth butadiene rubber synthesized using a rare earth element-based catalyst (rare earth BR), and butadiene rubber containing 1,2-syndiotactic polybutadiene crystals (SPB) Various BRs such as containing BR) and modified butadiene rubber (modified BR) can be used. As such BR, for example, those manufactured by Ube Industries, ZEON CORPORATION, LANXESS, and the like can be suitably used.

  High cis BR is a butadiene rubber having a cis-1,4 bond content of 90% by mass or more. Among them, the cis-1,4 bond content is preferably 95% by mass or more, more preferably 96% by mass or more, still more preferably 97% by mass or more, and 98% by mass or more. Is more preferable. By containing the high cis BR, low temperature characteristics and wear resistance can be improved. The cis-1,4 bond content in BR is a value calculated by infrared absorption spectrum analysis.

  The rare earth BR is synthesized using a rare earth element-based catalyst, and the vinyl content (1,2 bond butadiene unit amount) is 1.8% by mass or less, preferably 1.0% by mass or less, more preferably 0.8%. Those having a cis content (cis-1,4 bond content) of 90% by mass or more, preferably 93% by mass or more, and more preferably 95% by mass or more can be suitably used. When the vinyl content and the cis-1,4 bond content are within the above ranges, the resulting rubber composition has the effect of excellent elongation at break and wear resistance. The vinyl content and cis content of the rare earth BR are values measured by infrared absorption spectrum analysis.

  As the rare earth element-based catalyst used for the synthesis of the rare earth-based BR, known catalysts can be used, for example, a lanthanum series rare earth element compound, an organoaluminum compound, an aluminoxane, a halogen-containing compound, and a catalyst containing a Lewis base as necessary. Can be given.

  The SPB-containing BR includes not only those in which 1,2-syndiotactic polybutadiene crystals are dispersed in the BR, but are dispersed after being chemically bonded to the BR. When the crystal is chemically bonded to the rubber component and then dispersed, the complex elastic modulus tends to be improved.

  Examples of the modified BR include a modified BR whose terminal and / or main chain is modified, a modified BR coupled with tin, a silicon compound, etc. (condensate, one having a branched structure, etc.), a functional group that interacts with silica. And a modified BR having at least one selected from the group consisting of a silyl group, an amino group, an amide group, a hydroxyl group, and an epoxy group. By using the modified BR, it is possible to obtain an effect that the interaction with the filler is made stronger and the fuel efficiency is excellent.

  In the case of containing BR, the content in the rubber component is preferably 1% by mass or more, more preferably 5% by mass or more, more preferably 7% by mass or more, and further preferably 10% by mass or more from the viewpoint of wear resistance. . Further, the content of BR is preferably 35% by mass or less, more preferably 30% by mass or less, more preferably 28% by mass or less, and further preferably 25% by mass or less from the viewpoint of moldability.

<Silica>
The rubber composition for tires according to this embodiment is characterized by containing silica as a filler. By containing silica, the effect of improving fuel economy can be suitably obtained, and high reinforcement can be obtained.

  Silica is generally difficult to disperse in the rubber composition, but according to the rubber composition comprising the aminoguanidine weak acid salt of this embodiment, it can be dispersed well and balances excellent rubber performance. It is possible to express well.

  Silica is not particularly limited, and for example, silica that is prepared by a dry method (anhydrous silica), silica that is prepared by a wet method (hydrous silica), and the like can be used. Of these, hydrous silica prepared by a wet method is preferred because of its large number of silanol groups. Silica may be used alone or in combination of two or more.

The N ₂ SA of silica is preferably 70 m ² / g or more, more preferably 80 m ² / g or more, and further preferably 90 m ² / g or more. Further, although not limit N ₂ SA is particularly limited, from the viewpoint of easy handling, for example, preferably 500 meters ² / g or less, more preferably 400 meters ² / g, is 300 meters ² / g or less more preferably, more preferably 280 meters ² / g or less, more preferably 250 meters ² / g, more preferably 230 m ² / g or less. By using silica in which N ₂ SA is within the above range, low fuel consumption and molding processability can be improved in a balanced manner. The N ₂ SA of silica is a value measured by the BET method according to ASTM D3037-81.

  The content of silica with respect to 100 parts by mass of the rubber component is preferably within a predetermined range, for example, 40 to 150 parts by mass, from the viewpoints of silica dispersibility, low fuel consumption, molding processability, and the like. The content of silica is preferably 45 parts by mass or more, more preferably 50 parts by mass or more, more preferably 55 parts by mass or more, more preferably 60 parts by mass or more, more preferably 65 parts by mass or more, more preferably 70 parts by mass. Part or more, more preferably 75 parts by weight or more, and still more preferably 80 parts by weight or more. The silica content is preferably 150 parts by mass or less, more preferably 140 parts by mass or less, more preferably 130 parts by mass or less, more preferably 120 parts by mass or less, preferably 115 parts by mass or less, and more preferably 110 parts by mass. It is at most 100 parts by mass, more preferably at most 100 parts by mass.

<Other fillers>
In addition to silica, other fillers may be used as the filler. Such a filler is not particularly limited, and for example, any filler generally used in this field such as carbon black, aluminum hydroxide, alumina (aluminum oxide), calcium carbonate, talc, clay, etc. is used. be able to. These fillers may be used alone or in combination of two or more. When using a filler other than silica, carbon black is preferred from the viewpoint of rubber strength. That is, the filler preferably contains silica and carbon black, or preferably consists only of silica and carbon black.

(Carbon black)
Carbon black is not particularly limited, and those generally used in the tire industry such as GPF, FEF, HAF, ISAF, and SAF can be used.

N ₂ SA of carbon black is preferably 50 m ² / g or more, more preferably 70 m ² / g or more, and still more preferably 90 m ² / g or more, from the viewpoint of obtaining sufficient reinforcement and wear resistance. Also, N ₂ SA of carbon black is excellent in dispersibility, from the viewpoint that it is difficult to heat generation, preferably 500 meters ² / g or less, more preferably 450 m ² / g, more preferably from 300 meters ² / g or less, 250 meters ² / G or less is more preferable. The N ₂ SA of carbon black is a value measured according to JIS K 6217-2: 2001.

  The DBP oil absorption of carbon black is preferably 50 ml / 100 g or more, more preferably 100 ml / 100 g or more, from the viewpoint of wear resistance. The DBP oil absorption of carbon black is preferably 250 ml / 100 g or less, more preferably 200 ml / 100 g or less, and more preferably 150 ml / 100 g or less from the viewpoint of grip performance. In addition, the DBP oil absorption of carbon black is a value measured according to JIS K 6217-4: 2008.

  The content with respect to 100 parts by mass of the rubber component in the case of containing carbon black is preferably 1 part by mass or more, more preferably 3 parts by mass or more, and more preferably 5 parts by mass or more from the viewpoint of obtaining sufficient reinforcement and wear resistance. Is more preferable, and 7 mass parts or more is still more preferable. The content of carbon black is preferably 40 parts by mass or less, more preferably 30 parts by mass or less, more preferably 20 parts by mass or less, and 15 parts by mass from the viewpoints of moldability, fuel efficiency and wear resistance. The following is more preferable.

<Silane coupling agent>
As the silane coupling agent, a predetermined silane coupling agent having a mercapto group is used. The predetermined silane coupling agent having a mercapto group is a compound containing a binding unit I represented by the following formula (1) and a binding unit II represented by the following formula (2). By containing the silane coupling agent, fuel economy and breaking strength are improved. This compound may be used independently and may use 2 or more types together. In the present specification, a mercapto group means an SH group.

（式中、Ｒ¹は水素、ハロゲン、分岐もしくは非分岐の炭素数１〜３０のアルキル基、分岐もしくは非分岐の炭素数２〜３０のアルケニル基、分岐もしくは非分岐の炭素数２〜３０のアルキニル基、または該アルキル基の末端の水素が水酸基もしくはカルボキシル基で置換されたものを示す。Ｒ²は分岐もしくは非分岐の炭素数１〜３０のアルキレン基、分岐もしくは非分岐の炭素数２〜３０のアルケニレン基、または分岐もしくは非分岐の炭素数２〜３０のアルキニレン基を示す。Ｒ¹とＲ²とで環構造を形成してもよい。）

Wherein R ¹ is hydrogen, halogen, branched or unbranched C 1-30 alkyl group, branched or unbranched C 2-30 alkenyl group, branched or unbranched C 2-30 An alkynyl group, or a group in which hydrogen at the terminal of the alkyl group is substituted with a hydroxyl group or a carboxyl group, R ² represents a branched or unbranched alkylene group having 1 to 30 carbon atoms, a branched or unbranched carbon number of 2 30 represents an alkenylene group or a branched or unbranched alkynylene group having 2 to 30 carbon atoms, and R ¹ and R ² may form a ring structure.)

  Since the silane coupling agent having the above structure has a bond unit I and a bond unit II, an increase in viscosity during processing can be suppressed as compared with a polysulfide silane such as bis- (3-triethoxysilylpropyl) tetrasulfide. . This is presumably because the increase in Mooney viscosity is small because the sulfide portion of the bond unit I is a C—S—C bond and is thermally stable compared to tetrasulfide and disulfide.

  In the silane coupling agent having the above structure, the content of the bond unit I is preferably 30 mol% or more, and more preferably 50 mol% or more, from the viewpoint that the effect of the present embodiment can be obtained more favorably. Moreover, 99 mol% or less is preferable and, as for content of the coupling unit I, 90 mol% or less is more preferable. The content of the binding unit II is preferably 5 mol% or more, and more preferably 10 mol% or more. Further, the content of the bond unit II is preferably 65 mol% or less, and more preferably 55 mol% or less. The total content of the bonding units I and B is preferably 95 mol% or more, more preferably 98 mol% or more, and further preferably 100 mol%. In addition, content of the bond unit I and the bond unit II is an amount including the case where the bond unit I and the bond unit II are located at the terminal of the silane coupling agent. The form in which the bonding unit I and the bonding unit II are located at the terminal of the silane coupling agent is not particularly limited, and a unit corresponding to the formulas (1) and (2) indicating the bonding unit I and the bonding unit II is formed. It only has to be.

Examples of the halogen for R ¹ include chlorine, bromine and fluorine.

Examples of the branched or unbranched alkyl group having 1 to 30 carbon atoms of R ¹ include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, iso-butyl group, sec-butyl group, tert- Examples include butyl group, pentyl group, hexyl group, heptyl group, 2-ethylhexyl group, octyl group, nonyl group, decyl group and the like. As for carbon number of this alkyl group, 1-12 are preferable.

Examples of the branched or unbranched alkenyl group having 2 to 30 carbon atoms of R ¹ include vinyl group, 1-propenyl group, 2-propenyl group, 1-butenyl group, 2-butenyl group, 1-pentenyl group, and 2-pentenyl. Group, 1-hexenyl group, 2-hexenyl group, 1-octenyl group and the like. As for carbon number of this alkenyl group, 2-12 are preferable.

Examples of the branched or unbranched alkynyl group having 2 to 30 carbon atoms of R ¹ include ethynyl group, propynyl group, butynyl group, pentynyl group, hexynyl group, heptynyl group, octynyl group, nonynyl group, decynyl group, undecynyl group, And dodecynyl group. As for carbon number of this alkynyl group, 2-12 are preferable.

Examples of the branched or unbranched alkylene group having 1 to 30 carbon atoms of R ² include ethylene, propylene, butylene, pentylene, hexylene, heptylene, octylene, nonylene, decylene, undecylene, Examples include dodecylene group, tridecylene group, tetradecylene group, pentadecylene group, hexadecylene group, heptadecylene group, octadecylene group and the like. As for carbon number of this alkylene group, 1-12 are preferable.

Examples of the branched or unbranched C2-C30 alkenylene group of R ² include vinylene group, 1-propenylene group, 2-propenylene group, 1-butenylene group, 2-butenylene group, 1-pentenylene group and 2-pentenylene group. Group, 1-hexenylene group, 2-hexenylene group, 1-octenylene group and the like. As for carbon number of this alkenylene group, 2-12 are preferable.

Examples of the branched or unbranched alkynylene group having 2 to 30 carbon atoms of R ² include ethynylene group, propynylene group, butynylene group, pentynylene group, hexynylene group, heptynylene group, octynylene group, noninylene group, decynylene group, undecynylene group, And dodecynylene group. As for carbon number of this alkynylene group, 2-12 are preferable.

In the silane coupling agent having the above structure, the total number of repetitions (x + y) of the repeating number (x) of the bonding unit I and the repeating number (y) of the bonding unit II is preferably in the range of 3 to 300. Within this range, the mercaptosilane of the bond unit II is covered by —C ₇ H ₁₅ of the bond unit I, so that the scorch time can be prevented from being shortened, and good reactivity with silica and rubber components can be achieved. Can be secured.

  As the silane coupling agent having the above structure, for example, NXTZ30, NXT-Z45, NXT-Z60 manufactured by Momentive, etc. can be used. These may be used alone or in combination of two or more.

  The content with respect to 100 parts by mass of silica in the case of containing the silane coupling agent having the above structure is more preferably 1.0 part by mass or more, because sufficient silica dispersibility, effects such as viscosity reduction can be obtained, 2.0 parts by mass or more is more preferable, 4.0 parts by mass or more is more preferable, and 6.0 parts by mass or more is more preferable. In addition, the content of the silane coupling agent is preferably 20.0 parts by mass or less, and preferably 18.0 parts by mass or less, for efficiently obtaining a sufficient coupling effect and silica dispersion effect to ensure reinforcement. Is more preferable, and 15.0 parts by mass or less is more preferable.

≪Other silane coupling agents≫
As a silane coupling agent, as long as the effect by including the silane coupling agent of the said structure is ensured, you may substitute the one part with another silane coupling agent. Such a silane coupling agent is not particularly limited, and any silane coupling agent conventionally used in combination with silica can be used in the rubber industry.

  Examples of such other silane coupling agents include bis (3-triethoxysilylpropyl) tetrasulfide, bis (2-triethoxysilylethyl) tetrasulfide, bis (4-triethoxysilylbutyl) tetrasulfide, Bis (3-trimethoxysilylpropyl) tetrasulfide, bis (2-trimethoxysilylethyl) tetrasulfide, bis (4-trimethoxysilylbutyl) tetrasulfide, bis (3-triethoxysilylpropyl) trisulfide, bis ( 2-triethoxysilylethyl) trisulfide, bis (4-triethoxysilylbutyl) trisulfide, bis (3-trimethoxysilylpropyl) trisulfide, bis (2-trimethoxysilylethyl) trisulfide, bis (4- Trimethoxy Rylbutyl) trisulfide, bis (3-triethoxysilylpropyl) disulfide, bis (2-triethoxysilylethyl) disulfide, bis (4-triethoxysilylbutyl) disulfide, bis (3-trimethoxysilylpropyl) disulfide, bis (2-trimethoxysilylethyl) disulfide, bis (4-trimethoxysilylbutyl) disulfide, 3-trimethoxysilylpropyl-N, N-dimethylthiocarbamoyl tetrasulfide, 3-triethoxysilylpropyl-N, N-dimethyl Thiocarbamoyl tetrasulfide, 2-triethoxysilylethyl-N, N-dimethylthiocarbamoyl tetrasulfide, 2-trimethoxysilylethyl-N, N-dimethylthiocarbamoyl tetrasulfide, 3-triethoxy Silane coupling agents having a sulfide group such as toxisilylpropylbenzothiazolyl tetrasulfide, 3-triethoxysilylpropylbenzothiazole tetrasulfide, 3-trimethoxysilylpropyl methacrylate monosulfide; 3-mercaptopropyltrimethoxysilane, 3 Silane coupling agents having mercapto groups such as mercaptopropyltriethoxysilane, 2-mercaptoethyltrimethoxysilane, 2-mercaptoethyltriethoxysilane; silane cups having vinyl groups such as vinyltriethoxysilane and vinyltrimethoxysilane Ring agent: 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3- (2-aminoethyl) aminopropyltriethoxysilane, 3- Silane coupling agents having an amino group such as (2-aminoethyl) aminopropyltrimethoxysilane; γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldi Glycidoxy silane coupling agents such as ethoxysilane and γ-glycidoxypropylmethyldimethoxysilane; Nitro silane coupling agents such as 3-nitropropyltrimethoxysilane and 3-nitropropyltriethoxysilane; 3-chloro And chloro-based silane coupling agents such as propyltrimethoxysilane, 3-chloropropyltriethoxysilane, 2-chloroethyltrimethoxysilane, and 2-chloroethyltriethoxysilane. These silane coupling agents may be used individually by 1 type, and may be used in combination of 2 or more type.

<Aminoguanidine weak acid salt>
The rubber composition for tires according to this embodiment is characterized by containing an aminoguanidine weak acid salt.

  In this embodiment, the aminoguanidine weak acid salt is a salt composed of aminoguanidine and a weak acid, and the guanidine site of aminoguanidine forms a salt with a weak acid. The aminoguanidine weak acid salt may be a salt composed of one molecule of weak acid and one molecule of aminoguanidine, or may be a salt composed of one molecule of weak acid and two molecules of aminoguanidine.

  The aminoguanidine weak acid salt is not particularly limited as long as the effect of the present embodiment can be exhibited. As the weak acid used in the aminoguanidine weak acid salt, an organic acid or an inorganic acid can be used, but an inorganic acid is preferable. Specific examples of the aminoguanidine weak acid salt include aminoguanidine bicarbonate (aminoguanidine bicarbonate) composed of aminoguanidine and carbonic acid, aminoguanidine phosphate composed of aminoguanidine and phosphoric acid, and the like. Such aminoguanidine weak acid salts may be used alone or in combination of two or more. Among these, from the viewpoint that the effect of the present embodiment by containing aminoguanidine weak acid salt can be exhibited better, excellent in fuel efficiency and breaking strength, and further achieving both molding processability and vulcanization speed. It preferably contains at least one selected from the group consisting of aminoguanidine and aminoguanidine phosphate. The aminoguanidine weak acid salt is preferably aminoguanidine bicarbonate, or aminoguanidine phosphate, or preferably composed of aminoguanidine bicarbonate and aminoguanidine phosphate.

  The aminoguanidine weak acid salt of the present embodiment can be obtained by a known method, and examples thereof include a method of mixing aminoguanidine bicarbonate and a weak acid. Commercially available aminoguanidine bicarbonate and weak acid can be used. For example, those manufactured by Tokyo Chemical Industry Co., Ltd. can be used.

  It is preferable that content with respect to 100 mass parts of rubber components of aminoguanidine weak acid salt is 0.01-10 mass parts. The content of the aminoguanidine weak acid salt is preferably 0.05 parts by mass or more, more preferably 0.10 parts by mass or more, more preferably 0.30 parts by mass or more, and further preferably 0.50 parts by mass or more. Further, the content of aminoguanidine weak acid salt is preferably 9 parts by mass or less, more preferably 7 parts by mass or less, more preferably 5 parts by mass or less, more preferably 3 parts by mass or less, and more preferably 2.5 parts by mass or less. Preferably, it is 2.0 parts by mass or less. By setting it as such a range, the effect of this embodiment can be exhibited more favorably.

<Plasticizer>
The tire rubber composition according to the present embodiment preferably further contains a plasticizer.

  The plasticizer is not particularly limited, and plasticizers commonly used in the rubber industry and those used as softeners can be used. For example, they are known as resins, oils, liquid polymers, low-temperature plasticizers, and the like. Anything is included. A plasticizer may be used individually by 1 type and may be used in combination of 2 or more type. Especially, since the effect of this embodiment can be exhibited better, resin, oil, and liquid polymer are preferable, resin and oil are more preferable, and it is more preferable to use only resin and oil.

(resin)
The resin is not particularly limited, and any of those usually used in the rubber industry can be suitably used. For example, terpene resin, hydrogenated terpene resin, C5-C9 resin, styrene / α-methyl Examples thereof include styrene copolymer resins, adhesive resins, crosslinkable resins, and compatibilizing resins.

  The softening point of these resins is preferably in the range of −20 to 180 ° C. from the viewpoint of suitably exhibiting the function as a plasticizer. The upper limit of the softening point is preferably 170 ° C. or lower, more preferably 150 ° C. or lower, and further preferably 130 ° C. or lower. Further, the lower limit of the softening point is preferably −10 ° C. or higher, and more preferably −5 ° C. or higher. In addition, in this specification, the softening point of resin is the temperature at which the sphere descends when the softening point defined in JIS K 6220-1 is measured with a ring and ball softening point measuring device.

  The weight average molecular weight (Mw) of these resins is preferably within a predetermined range from the viewpoint of obtaining good moldability and ensuring rubber hardness. Specifically, Mw is preferably 120,000 or less, more preferably 10,000 or less, and even more preferably 5000 or less. Further, Mw is preferably 200 or more, more preferably 250 or more, further preferably 300 or more, and further preferably 350 or more. In this specification, the resin Mw is the gel permeation chromatograph (GPC) (GPC-8000 series, manufactured by Tosoh Corporation), detector: differential refractometer, column: TSKGEL SUPERMALTPORE HZ- manufactured by Tosoh Corporation. This is a value determined by standard polystyrene conversion based on the measured value according to M).

≪Styrene / α-methylstyrene copolymer resin≫
The styrene / α-methylstyrene copolymer resin is a resin obtained by polymerizing styrene and α-methylstyrene.

≪Hydrogenated terpene resin≫
The hydrogenated terpene resin is obtained by hydrogenating (hydrogenating) a terpene resin. The hydrogenation treatment to the terpene resin can be performed by a known method.

  The hydrogenated terpene resin is not particularly limited. For example, a polyterpene resin composed of at least one selected from terpene raw materials such as α-pinene, β-pinene, limonene, and dipentene, a terpene compound and an aromatic compound are used as raw materials. And a terpene resin such as a terpene phenol resin using a terpene compound and a phenol compound as raw materials. Here, as an aromatic compound used as the raw material of the aromatic modified terpene resin, for example, styrene, α-methylstyrene, vinyl toluene, divinyl toluene and the like can be mentioned, and as a phenolic compound used as a raw material of the terpene phenol resin. Examples thereof include phenol, bisphenol A, cresol, xylenol and the like.

≪Adhesive resin≫
The pressure-sensitive adhesive resin is usually an oligomer having a characteristic of being compatible or at least semi-compatible with the rubber component and having a molecular weight of several hundred to several tens of thousands. By blending the adhesive resin, the tackiness (moldability) of the unvulcanized product at the time of tire molding is improved. Here, the adhesive resin is not particularly limited, and any resin other than those described above and commonly used in the rubber industry can be suitably used. For example, phenolic resins, coumarone indene resins, terpene resins Examples thereof include resins, styrene resins, acrylic resins, rosin resins, and dicyclopentadiene resins (DCPD resins). Examples of phenolic resins include those manufactured by BASF and Taoka Chemical Industries, Ltd., and examples of coumarone indene resins include those manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., JXTG Energy Co., Ltd. As the styrene resin, for example, those manufactured by Arizona chemical can be used. As the terpene resin, for example, those manufactured by Arizona chemical and Yashara Chemical Co., Ltd. can be used. As the rosin resin, for example, those made by Harima Kasei Co., Ltd. or Arakawa Chemical Industries, Ltd. can be used. Especially, it is preferable to use a phenol resin, a coumarone indene resin, a terpene resin, and an acrylic resin because of excellent grip performance.

≪Liquid resin≫
As said resin, a liquid thing (liquid resin) can be used suitably from a viewpoint of exhibiting the effect as a plasticizer favorably. Here, the liquid resin refers to a resin that is not cured at room temperature (25 ° C.).

  As the liquid resin, for example, liquid coumarone indene resin, liquid terpene resin and the like can be suitably used. Among these, liquid coumarone indene resin is preferable.

  The liquid coumarone indene resin contains coumarone and indene as monomer components constituting the resin skeleton (main chain). In the skeleton, examples of monomer components other than coumarone and indene include styrene, α-methylstyrene, methylindene, and vinyltoluene. The softening point of the liquid coumarone indene resin is preferably -20 to 45 ° C. An upper limit becomes like this. Preferably it is 40 degrees C or less, More preferably, it is 35 degrees C or less. The lower limit is preferably −10 ° C. or higher, more preferably −5 ° C. or higher. As the liquid coumarone indene resin, for example, those manufactured by Rutgers Chemicals can be preferably used.

(oil)
The oil is not particularly limited, and any oil usually used in the rubber industry can be suitably used. Examples thereof include process oil, vegetable oil and animal oil. Examples of the process oil include paraffinic process oil, naphthenic process oil, and aromatic process oil. Vegetable oils include castor oil, cottonseed oil, linseed oil, rapeseed oil, soybean oil, palm oil, palm oil, peanut oil, rosin, pine oil, pine tar, tall oil, corn oil, rice bran oil, sesame oil, olive oil, sunflower Oil, palm kernel oil, cocoon oil, jojoba oil, macadamia nut oil, safflower oil, tung oil and the like. Animal fats and oils include oleyl alcohol, fish oil, and beef tallow. Among them, a process oil is preferable because it is advantageous for processability, and a process oil (low PCA content) with a low content of polycyclic aromatic compound (PCA) is preferable because it reduces environmental burden. Process oil) is preferred.

  Low PCA content process oils include: Treated Distillate Aromatic Extract (TDAE), which is a re-extracted oil aromatic process oil, aroma substitute oil that is a mixed oil of asphalt and naphthenic oil, and mild extraction solvates (MES). ) And heavy naphthenic oils.

(Liquid polymer)
The liquid polymer is preferably a liquid polymer having a polystyrene-reduced weight average molecular weight of 1.0 × 10 ^{3 to} 2.0 × 10 ⁵ measured by gel permeation chromatography (GPC). By setting it as such a range, there exists a tendency for a destructive characteristic, durability, and moldability to be obtained with sufficient balance.

  The liquid polymer is not particularly limited, and any polymer usually used in the rubber industry can be suitably used. Examples thereof include liquid SBR, liquid BR, liquid IR, and liquid SIR. Especially, it is preferable to use liquid SBR from the reason that durability performance and grip performance can be improved in a well-balanced manner.

(Low temperature plasticizer)
The low-temperature plasticizer is not particularly limited, and any of those usually used in the rubber industry can be suitably used. For example, dibutyl adipate (DBA), diisobutyl adipate (DIBA), dioctyl adipate (DOA) ), Di-2-ethylhexyl azelate (DOZ), dibutyl sebacate (DBS), diisononyl adipate (DINA), diethyl phthalate (DEP), dioctyl phthalate (DOP), diundecyl phthalate (DUP), dibutyl phthalate (DBP), dioctyl sebacate (DOS), tributyl phosphate (TBP), trioctyl phosphate (TOP), triethyl phosphate (TEP), trimethyl phosphate (TMP), thymidine triphosphate (TTP), tricresyl phosphate ( TCP), trixylenyl phosphate ( Such as ester plasticizers XP), and the like. Of these, DOS and TOP are preferable in view of the balance between the plastic effect at low temperatures and the wear resistance, and DOS is preferable because of excellent fuel efficiency.

  The freezing point of the low temperature plasticizer is preferably −50 ° C. or lower, more preferably −70 ° C. or lower, from the viewpoint of sufficient grip improvement effect. Moreover, the minimum of the freezing point of a low temperature plasticizer is not specifically limited.

  The viscosity of the low-temperature plasticizer at 25 ° C. is preferably 30 mPa · s or less, more preferably 20 mPa · s or less, from the viewpoint of sufficient grip improvement effect. Moreover, the minimum of the viscosity of a low temperature plasticizer is not specifically limited.

(Content)
The content of the plasticizer with respect to 100 parts by mass of the rubber component is preferably within a predetermined range from the viewpoint of low fuel consumption and wear resistance. That is, the content of the plasticizer is preferably 10 parts by mass or more, more preferably 20 parts by mass or more, further preferably 30 parts by mass or more, preferably 35 parts by mass or more, and more preferably 40 parts by mass or more. Moreover, 100 mass parts or less are preferable, as for content of a plasticizer, 80 mass parts or less are more preferable, 70 mass parts or less are more preferable, and 60 mass parts or less are more preferable. In addition to the oil component contained in oil-extended rubber and insoluble sulfur, the amount of plasticizer includes post-added oil (oil blended separately from the oil component contained in oil-extended rubber and insoluble sulfur). .

  In the plasticizer, the content of the resin is preferably 1 part by mass or more, more preferably 5 parts by mass or more, more preferably 10 parts by mass or more, more preferably 15 parts by mass or more, and further preferably 20 parts by mass or more. Moreover, 60 mass parts or less are preferable, as for content of the said resin, 50 mass parts or less are more preferable, 45 mass parts or less are more preferable, and 40 mass parts or less are further more preferable.

  When only oil and resin are used as the plasticizer, the content of the oil with respect to 100 parts by mass of the rubber component is obtained by removing the resin content from the plasticizer content.

<Other ingredients>
In the rubber composition according to the present embodiment, in addition to the above components, compounding agents generally used in the production of rubber compositions, such as zinc oxide, stearic acid, anti-aging agents, waxes, vulcanizing agents, A vulcanization accelerator or the like can be appropriately blended.

(Anti-aging agent)
The anti-aging agent is not particularly limited, and any of those usually used in the rubber industry can be suitably used. For example, amine / ketone anti-aging agent, imidazole anti-aging agent, amine anti-aging agent And phenol-based anti-aging agents, sulfur-based anti-aging agents, and phosphorus-based anti-aging agents. Antiaging agents may be used alone or in combination of two or more.

  When the anti-aging agent is contained, the content with respect to 100 parts by mass of the rubber component is preferably 0.5 parts by mass or more, and more preferably 1.0 part by mass or more. Moreover, 7 mass parts or less are preferable, and, as for content of anti-aging agent, 5 mass parts or less are more preferable. By setting it as such a range, the effect of this embodiment can be exhibited more favorably.

(wax)
The wax is not particularly limited, and any of those usually used in the rubber industry can be suitably used, and examples thereof include paraffin waxes manufactured by Nippon Seiki Co., Ltd., Paramelt Co., etc. Waxes may be used alone or in combination of two or more.

  When the wax is contained, the content with respect to 100 parts by mass of the rubber component is preferably 0.5 parts by mass or more, more preferably 1.0 part by mass or more, and further preferably 1.2 parts by mass or more. Moreover, 3.0 mass parts or less are preferable, 2.5 mass parts or less are more preferable, and 2.0 mass parts or less are further more preferable. By setting it as such a range, the effect of this embodiment can be exhibited more favorably.

(Vulcanizing agent)
The vulcanizing agent is not particularly limited, and a known vulcanizing agent can be used. Examples thereof include sulfur, organic peroxides, resin vulcanizing agents, and metal oxides such as magnesium oxide. Of these, sulfur is preferably used. Examples of sulfur include powdered sulfur, precipitated sulfur, colloidal sulfur, surface-treated sulfur, insoluble sulfur, and the like, and any of them is preferably used. A vulcanizing agent may be used individually by 1 type, and may be used in combination of 2 or more type.

  The content with respect to 100 parts by mass of the rubber component when sulfur is contained as a vulcanizing agent is preferably 0.5 parts by mass or more, and more preferably 1.0 part by mass or more. The sulfur content is preferably 7 parts by mass or less, and more preferably 5 parts by mass or less. By setting it as such a range, the effect of this embodiment can be exhibited more favorably.

(Vulcanization accelerator)
The vulcanization accelerator is not particularly limited, and known vulcanization aids can be used. For example, sulfenamide, thiazole, thiuram, thiourea, guanidine, dithiocarbamic acid, aldehyde-amine And aldehyde-ammonia, imidazoline, or xanthate vulcanization accelerators. Of these, sulfenamide type and guanidine type are preferable because the scorch time and vulcanization time can be well balanced. A vulcanization accelerator may be used individually by 1 type, and may be used in combination of 2 or more type.

  Examples of the sulfenamide vulcanization accelerator include N-tert-butyl-2-benzothiazolylsulfenamide (TBBS), N-cyclohexyl-2-benzothiazolylsulfenamide (CBS), N, N And '-dicyclohexyl-2-benzothiazolylsulfenamide (DZ). Of these, N-cyclohexyl-2-benzothiazolylsulfenamide (CBS) is preferable.

  Examples of the guanidine vulcanization accelerator include 1,3-diphenylguanidine (DPG), diortolylguanidine, orthotolylbiguanidine, and the like. Of these, 1,3-diphenylguanidine (DPG) is preferable from the viewpoint of shortening the vulcanization time.

  In the present embodiment, N-cyclohexyl-2-benzothiazolylsulfenamide (CBS) and 1,3-diphenylguanidine (CBS) are used as vulcanization accelerators because the effects of the present embodiment can be exhibited better. More preferably, only DPG) is used.

  When the vulcanization accelerator is contained, the content with respect to 100 parts by mass of the rubber component is preferably 0.5 parts by mass or more, more preferably 1.0 part by mass or more, and further preferably 2.0 parts by mass or more. Further, the content of the vulcanization accelerator is preferably 5.0 parts by mass or less, more preferably 4.0 parts by mass or less, and further preferably 3.5 parts by mass or less. By setting it as such a range, the effect of this embodiment can be exhibited more favorably.

<Manufacture of rubber composition for tire>
The tire rubber composition of the present embodiment is produced by a known method. For example, it can be produced by a method of kneading each component with a Banbury mixer, a kneader, an open roll or the like and then vulcanizing. In kneading, first, components other than the vulcanizing agent and the vulcanization accelerator can be kneaded, and then the obtained kneaded product can be kneaded with the vulcanizing agent and the vulcanization accelerator. In addition, the blending method of aminoguanidine weak acid salt is not particularly limited and can be blended as a powder as it is, but besides such blending method, for example, a method of dissolving in a solvent and blending as a solution, It can also mix | blend by the method of mix | blending as an emulsion solution.

<Rubber composition for tire>
The rubber composition for tires of this embodiment can be used for tire members such as tire treads, undertreads, carcass, sidewalls, and beads. In particular, a tire having a tread composed of the rubber composition for a tire of the present embodiment is preferable because of excellent fuel economy, breaking strength, and wear resistance.

<Manufacture of tires>
The tire of the present embodiment can be produced by a normal method using the tire rubber composition. That is, the tire rubber composition is extruded in accordance with the shape of a tire member such as a tread of a tire at an unvulcanized stage, molded by a normal method on a tire molding machine, and pasted together with other tire members. Together, an unvulcanized tire is formed. The tire of this embodiment can be manufactured by heating and pressurizing this unvulcanized tire in a vulcanizer. The vulcanization temperature is not particularly limited as long as it is a general vulcanization temperature in the tire industry, and is, for example, 120 ° C. or higher and 200 ° C. or lower, preferably 140 ° C. or higher, and preferably 180 ° C. or lower.

<Tire>
The tire of this embodiment may be a pneumatic tire or a non-pneumatic tire, but is preferably a pneumatic tire. Moreover, as a pneumatic tire, it can be used for various tires such as tires for passenger cars, tires for trucks and buses, tires for motorcycles, high performance tires such as racing tires, and run-flat tires.

<Others>
In this specification, when the numerical range is expressed as “10 to 100”, the numerical range includes the values at both ends unless otherwise specified.

  Although this embodiment is described based on an Example, this embodiment is not limited only to an Example.

Various chemicals used in Examples and Comparative Examples are collectively shown below.
Natural rubber (NR): TSR20
Styrene butadiene rubber (SBR): Asaprene E15 from Asahi Kasei Corporation
Butadiene rubber (BR): BR150B manufactured by Ube Industries, Ltd.
Silica: Ultrasil VN3 (N ₂ SA (BET): 175 m ² / g) manufactured by Evonik
Silane coupling agent (coupling agent) 1: Si75 (bis (3-triethoxysilylpropyl) disulfide) manufactured by Evonik
Silane coupling agent (coupling agent) 2: NXT-Z45 manufactured by Momentive (copolymer of bond unit I (55 mol%) and bond unit II (45 mol%))
Resin: SYLVATRAXX4401 manufactured by Arizona Chemical
Oil: Diana Process Oil PA32 manufactured by Idemitsu Kosan Co., Ltd.
Anti-aging agent: NOCRACK 6C (N- (1,3-dimethylbutyl) -N′-phenyl-p-phenylenediamine) manufactured by Ouchi Shinsei Chemical Industry Co., Ltd.
Wax: Ozoace 0355 manufactured by Nippon Seiwa Co., Ltd.
Zinc stearate sulfur vulcanization accelerator 1: N-cyclohexyl-2-benzothiazolylsulfenamide (CBS)
Vulcanization accelerator 2: 1,3-diphenylguanidine (DPG)
Aminoguanidine weak acid salt 1 (AG weak acid salt 1): Aminoguanidine phosphate Aminoguanidine weak acid salt 2 (AG weak acid salt 2): Aminoguanidine bicarbonate

Examples 1-2 and Comparative Examples 1-4
Of the contents shown in Table 1, various chemicals (except for sulfur and vulcanization accelerators 1 and 2) are kneaded with a Banbury mixer to obtain a kneaded product. Next, using an open roll, sulfur and vulcanization accelerators 1 and 2 are added to the kneaded product and kneaded to obtain an unvulcanized rubber composition.

  The unvulcanized rubber composition is molded into a desired shape and press vulcanized at 170 ° C. to produce a vulcanized rubber composition. The vulcanization time is set to be twice as long as the vulcanization characteristic t90 at 170 ° C. obtained below.

  Extruding the unvulcanized rubber composition with an extruder equipped with a tread-shaped die, bonding together with other tire members to form an unvulcanized tire, and press vulcanizing under a condition of 170 ° C. Thus, a test tire (size: 195 / 65R15) is manufactured.

<Molding processability>
The unvulcanized rubber composition was subjected to a vulcanization test at a measurement temperature of 130 ° C. using a vibration vulcanization tester (curlastometer) described in JIS K 6300, and the time and torque plotted. A sulfur velocity curve is obtained. The time t10 (scorch time) (minute) to reach ML + 0.1ME is read, where ML is the minimum value of the torque of the vulcanization speed curve, MH is the maximum value, and ME is the difference (MH−ML). Using the scorch time of the reference comparative example as 100, the index is displayed by the following formula. The larger the value, the longer the scorch time and the better the processability.
(Molding processability index) =
{(Scorch time of each formulation) / (Scorch time of reference comparative example)} × 100

<Vulcanization speed>
About an unvulcanized rubber composition, the vulcanization characteristic t90 of 170 degreeC is calculated | required using a viscoelasticity measuring apparatus (The alpha technology company make, brand name: RPA2000), and it is set as vulcanization time. The vulcanization time of the reference comparative example is taken as 100, and the index is expressed by the following formula. The larger the value, the shorter the vulcanization time.
(Vulcanization rate index) = {(Vulcanization time of reference comparative example) / (Vulcanization time of each compound)} × 100

<Destructive strength>
Using a No. 6 dumbbell-shaped test piece made of a vulcanized rubber composition, a tensile test was performed in an atmosphere at 25 ° C. in accordance with JIS K 6251: 2010 “Vulcanized rubber and thermoplastic rubber-Determination of tensile properties”. The breaking strength TB (MPa) and the elongation at break EB (%) are measured. Then, a value of TB × EB / 2 (MPa%) is calculated. The calculated value is converted into an index with the reference comparative example being 100 by the following formula. It shows that it is excellent in fracture strength, so that a numerical value is large.
(Fracture strength index) = {(value of each formulation) / (value of reference comparative example)} × 100

<Low fuel consumption>
About the vulcanized rubber composition, the loss tangent of each compounding composition under the conditions of a temperature of 50 ° C., an initial strain of 10%, a dynamic strain of 2%, and a frequency of 10 Hz using a viscoelastic spectrometer VES (manufactured by Iwamoto Seisakusho Co., Ltd.) tan δ _{50 ° C.} ), the fuel efficiency index of the reference comparative example is taken as 100, and the fuel efficiency of each formulation is displayed as an index according to the following formula. Larger values indicate lower rolling resistance and better fuel efficiency.
(Low fuel consumption index) =
{(Tan δ _{50 ° C.} of reference comparative example) / (tan δ _{50 ° C. of} each formulation)} × 100

  Each index or a value close to it is obtained by performing each of the above tests based on the blending contents of Table 1.

  In this embodiment, the target value of the moldability index is not 100 or less. Further, the breaking strength index and the low fuel consumption index exceed 100, and it is desirable that the index is as large as possible.

Claims (7)

Rubber component,
Silica,
A compound comprising a binding unit I represented by the following formula (1) and a binding unit II represented by the following formula (2);
A rubber composition for tires comprising an aminoguanidine weak acid salt.

Wherein R ¹ is hydrogen, halogen, branched or unbranched C 1-30 alkyl group, branched or unbranched C 2-30 alkenyl group, branched or unbranched C 2-30 An alkynyl group, or a group in which hydrogen at the terminal of the alkyl group is substituted with a hydroxyl group or a carboxyl group, R ² represents a branched or unbranched alkylene group having 1 to 30 carbon atoms, a branched or unbranched carbon number of 2 30 represents an alkenylene group or a branched or unbranched alkynylene group having 2 to 30 carbon atoms, and R ¹ and R ² may form a ring structure.) The tire rubber composition according to claim 1, wherein the aminoguanidine weak acid salt is at least one selected from the group consisting of aminoguanidine bicarbonate and aminoguanidine phosphate. The rubber composition for tires according to claim 1 or 2 whose content of aminoguanidine weak acid salt is 0.01-10 mass parts to 100 mass parts of rubber components. The rubber composition for a tire according to any one of claims 1 to 3, further comprising 30 parts by mass or more of a plasticizer, wherein the resin content of the plasticizer is 5 parts by mass or more. The tire rubber composition according to any one of claims 1 to 4, wherein the rubber component is a rubber component containing 50% by mass or more of styrene butadiene rubber. The rubber composition for tires according to any one of claims 1 to 5, wherein the silica content is 80 parts by mass or more with respect to 100 parts by mass of the rubber component. The tire which has a tire member comprised from the rubber composition for tires of any one of Claims 1-6.