JP2018177920A - Rubber composition and tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rubber composition and a tire having excellent processability, wear resistance and grip performance in a balanced manner and suppressing bleeding.SOLUTION: The rubber composition comprises: a rubber component containing a conjugate diene polymer (component A) by 60 mass% or more, which has a weight average molecular weight of 1.5×10to 3.0×10and an aromatic vinyl content of 60 mass% or less; a conjugate diene polymer (component B) by 10 to 200 parts by mass with respect to 100 parts by mass of the above rubber component, which has a weight average molecular weight of 1.0×10to 1.0×10, an aromatic vinyl content of 70 mass% or less, a vinyl bond amount of 20 to 70% in a conjugate diene moiety, a hydrogenation rate of 56% or more, and a viscosity of 100000 or more measured by a B-type viscometer at 25°C; and predetermined component C and component D. The total content of component B, component C and component D is 80 parts by mass or more. An absolute value of the difference between the aromatic vinyl content of the component A and the aromatic vinyl content of component B is less than 15, otherwise, the aromatic vinyl content of component A is greater than the aromatic content of component B as well as an absolute value of the difference between the aromatic vinyl content of component A and the aromatic content of component B is less than 20.SELECTED DRAWING: None

Description

  The present invention relates to rubber compositions and tires.

  BACKGROUND OF THE INVENTION Tire tread rubber, particularly high performance tire tread rubber, is generally required to have both high grip performance and wear resistance.

  Conventionally, various measures have been studied in order to obtain a rubber composition exhibiting high grip performance. For example, a rubber composition using a styrene-butadiene copolymer rubber (SBR) having a high glass transition temperature (Tg) as a rubber component, and a liquid component (softener component) such as process oil being equivalently substituted to a high softening point resin Rubber compositions filled with a rubber component, rubber compositions highly filled with a softener or carbon black, rubber compositions using carbon black having a small particle diameter, or rubber compositions obtained by combining the above measures. ing.

  However, a rubber composition using an SBR having a high Tg has a problem that the temperature dependency is large and the performance change with respect to the temperature change is large. In addition, when the process oil is replaced with a high softening point resin in an equal amount, if the replacement amount is large, there is a problem that the temperature dependence becomes large due to the influence of the high softening point resin. Furthermore, when carbon black having a small particle size or a large amount of a softener is used, there is a problem that the dispersibility of the carbon black is poor and the abrasion resistance is lowered.

  Patent Document 1 proposes a rubber composition using a low molecular weight styrene-butadiene copolymer in order to solve the above problems. However, a low molecular weight styrene-butadiene copolymer has a crosslinkable double bond, and a part of low molecular weight components form a crosslink with the rubber component of the matrix to be incorporated into the matrix, and the hysteresis loss is sufficiently reduced. There is a problem that it can not be suppressed. In addition, in order to prevent low molecular weight components from being incorporated into the matrix by crosslinking, when the double bond portion is saturated by hydrogenation, the compatibility with the matrix is significantly reduced, and as a result, the fracture resistance is reduced. And low molecular weight components may bleed.

  Patent Document 2 describes a rubber composition containing a low molecular weight styrene-butadiene copolymer having a hydrogenation rate of 43 to 55% in order to solve the above problems, but the hydrogenation rate is not good. It is sufficient, and it is inadequate in terms of coexistence of grip performance and abrasion resistance.

Japanese Patent Application Laid-Open No. 63-101440 Patent No. 4113847 gazette

  The object of the present invention is to provide a rubber composition which is excellent in processability, abrasion resistance and grip performance in a well-balanced manner and which further suppresses bleeding, and a tire having a tire member constituted by the rubber composition. Do.

The present invention comprises 60% by mass or more of a conjugated diene polymer (component A) having a weight-average molecular weight of 1.5 × 10 ^{5 to} 3.0 × 10 ⁶ and an aromatic vinyl content of 60% by mass or less For 100 parts by mass of rubber component,
Weight average molecular weight is 1.0 × 10 ^{3 to} 1.0 × 10 ⁵ , aromatic vinyl content is 70% by mass or less, vinyl bond content of conjugated diene portion is 20 to 70%, hydrogenation Of 10 to 200 parts by mass of a conjugated diene polymer (component B) having a viscosity of 56% or more and a viscosity of 100,000 or more measured by a B-type viscometer at 25 ° C.
5 parts by mass or more of a resin (component C) which has a freezing point of 25 ° C. or higher and is solid at 25 ° C.,
A rubber composition containing 5 parts by mass or more of a liquid plasticizer (component D) having a freezing point of 20 ° C. or less and a viscosity measured by a B-type viscometer at 25 ° C. of less than 100,000.
The total content of component B, component C and component D is 80 parts by mass or more,
The absolute value of the difference between the aromatic vinyl content of Component A and the aromatic vinyl content of Component B is less than 15, or the aromatic vinyl content of Component A is greater than the aromatic vinyl content of Component B The present invention relates to a rubber composition which is large and which has a difference between the aromatic vinyl content of component A and the absolute value of the aromatic vinyl content of component B of less than 20.

  It is preferable that the vinyl bond amount of the conjugated diene part of component A is 20 to 60%.

  Both Component A and Component B are preferably polymers polymerized from at least one or more of monomers having a conjugated diene structure.

  Component C is preferably an organic substance having a cyclic conjugated diene structure.

  It is preferable that the flash point of the component D is 200 ° C. or higher.

  Furthermore, it is preferable to contain a filler.

  The present invention also relates to a tire having a tire member constituted by the above rubber composition.

  A tire having a rubber composition of the present invention and a tire member composed of the rubber composition is a rubber composition and a tire which are excellent in processability, abrasion resistance and grip performance in a well-balanced manner, and in which bleeding is suppressed. .

A rubber composition according to an embodiment of the present invention has a weight average molecular weight of 1.5 × 10 ^{5 to} 3.0 × 10 ⁶ and a conjugated diene polymer having an aromatic vinyl content of 60% by mass or less ( The weight-average molecular weight is 1.0 × 10 ^{3 to} 1.0 × 10 ⁵ and the aromatic vinyl content is 70% by mass or less with respect to 100 parts by mass of the rubber component containing 60% by mass or more of the component A) A conjugated diene polymer (component B) having a vinyl bond content of a conjugated diene portion of 20 to 70%, a hydrogenation rate of 56% or more, and a viscosity measured by a B-type viscometer at 25 ° C. of 100,000 or more And the total content of component B, component C and component D is 80 parts by mass or more, and the aromatic vinyl of component A is a rubber composition containing 10 to 200 parts by mass of component C and component D). The absolute value of the difference between the content and the aromatic vinyl content of component B is 1 Or less than the aromatic vinyl content of component A is greater than the aromatic vinyl content of component B and the absolute value of the aromatic vinyl content of component A and the aromatic vinyl content of component B A rubber composition having a difference of less than 20.

  The rubber composition of the present embodiment is processed by containing a conjugated diene polymer (Component A) having a specific microstructure and a low molecular weight conjugated diene polymer (Component B) having a specific hydrogenation rate. It is a rubber composition which was successful in achieving a high degree of balance between the properties, the wear resistance and the grip performance and further suppressing the bleeding.

Component A is a conjugated diene polymer having a weight average molecular weight of 1.5 × 10 ^{5 to} 3.0 × 10 ⁶ and an aromatic vinyl content of 60% by mass or less.

The weight average molecular weight of the component A is 1.5 × 10 ⁵ or more, preferably 1.7 × 10 ⁵ or more. If it is less than 1.5 × 10 ⁵ , the wear resistance may be reduced. Further, the weight average molecular weight of the component A is 3.0 × 10 ⁶ or less, preferably 2.0 × 10 ⁶ or less. If it exceeds 3.0 × 10 ⁶ , the processability may be deteriorated.

  The aromatic vinyl content of the component A is 60% by mass or less, more preferably 50% by mass or less, and still more preferably 45% by mass or less. If it exceeds 60% by mass, the abrasion resistance or the grip performance at low temperature may be deteriorated. Further, the lower limit of the aromatic vinyl content of the component A is not particularly limited.

  From the viewpoint of grip performance, 20% or more is preferable, and 30% or more of the vinyl bond amount of the conjugated diene portion of the component A is more preferable. In addition, the amount of vinyl bond in the conjugated diene portion of the component A is preferably 60% or less, more preferably 50% or less, from the viewpoint of wear resistance and grip performance at low temperature.

  Examples of the aromatic vinyl component constituting the component A include styrene, α-methylstyrene, 1-vinylnaphthalene, 3-vinyltoluene, ethylvinylbenzene, divinylbenzene, 4-cyclohexylstyrene, 2,4-trimethylstyrene and the like And vinyl aromatic hydrocarbon monomers of These may be used alone or in combination of two or more. Among them, styrene is preferred.

  Examples of the conjugated diene component constituting the component A include 1,3-butadiene, isoprene, 1,3-pentadiene, 2,3-dimethylbutadiene, 2-phenyl-1,3-butadiene, myrcene, farnesene and the like. Be These may be used alone or in combination of two or more. Among these, 1,3-butadiene is preferable.

  As a component A, a styrene butadiene copolymer, a styrene isoprene copolymer, a styrene- myrcene copolymer etc. are mentioned, for example. Among them, styrene-butadiene copolymer is preferable from the viewpoint of versatility.

  Content in the rubber component of component A is 60 mass% or more, and 80 mass% or more is preferable. If the amount is less than 60% by mass, the grip performance may be insufficient. Further, the upper limit of the content of the component A in the rubber component is not particularly limited, and 100% by mass is preferable from the viewpoint that the effect of containing the component A is further obtained.

  The rubber component may contain a rubber component (other rubber component) other than the component A. Other rubber components include isoprene rubber including natural rubber (NR) and polyisoprene rubber (IR), butadiene rubber (BR), styrene isoprene butadiene rubber (SIBR), chloroprene rubber (CR), acrylonitrile butadiene rubber (NBR And the like. The rubber component may be used alone or in combination of two or more. It is preferable to contain NR and BR from the viewpoint of balance of low fuel consumption, abrasion resistance, durability and wet grip performance, but other rubber components are preferable from the viewpoint that the effect of containing component A is obtained more It is preferable not to contain it.

The rubber composition according to the present embodiment has a weight average molecular weight of 1.0 × 10 ^{3 to} 1.0 × 10 ⁵ and an aromatic vinyl content of 70% by mass or less in the rubber component containing the component A. A conjugated diene polymer having a vinyl bond content of a conjugated diene portion of 20 to 70%, a hydrogenation rate of 56% or more, and a viscosity measured by a B-type viscometer at 25 ° C. of 100,000 or more (components By containing B), abrasion resistance and grip performance can be balanced to a high degree, and bleeding can be further suppressed.

The weight average molecular weight of the component B is 1.0 × 10 ³ or more, preferably 2.0 × 10 ³ or more. If it is less than 1.0 × 10 ³ , the wear resistance may be reduced. The weight average molecular weight of the component B is 1.0 × 10 ⁵ or less, preferably 8.0 × 10 ⁴ or less. If it exceeds 1.0 × 10 ⁵ , the grip performance may be deteriorated.

  The aromatic vinyl content of component B is 70% by mass or less, preferably 65% by mass or less. If it exceeds 70% by mass, the abrasion resistance may be reduced. The lower limit of the aromatic vinyl content of component B is not particularly limited.

  From the viewpoint of grip performance, 20% or more is preferable, and 30% or more of the vinyl bond amount of the conjugated diene portion of the component B is more preferable. In addition, the amount of vinyl bond in the conjugated diene portion of the component B is preferably 70% or less, more preferably 60% or less, from the viewpoint of wear resistance and grip performance at low temperature.

  The hydrogenation rate of the component B is 56% or more, preferably 65% or more. If it is less than 56%, the component B may be taken into the rubber component which is the matrix and the grip performance may be insufficient. Further, the upper limit of the hydrogenation rate of the component B is not particularly limited as long as the effects of the present invention are not impaired. In addition, the hydrogenation rate of the component B is a hydrogenation rate of the double bond of the conjugated diene part of the component B.

  The viscosity measured by a B-type viscometer at 25 ° C. of component B is 100,000 or more, and preferably 200,000 or more. If the viscosity is less than 100,000, sufficient grip performance may not be obtained. Further, the upper limit of the viscosity measured by a B-type viscometer at 25 ° C. of the component B is not particularly limited as long as the component B is a liquid having viscosity.

  Examples of the aromatic vinyl component constituting the component B include styrene, α-methylstyrene, 1-vinylnaphthalene, 3-vinyltoluene, ethylvinylbenzene, divinylbenzene, 4-cyclohexylstyrene, 2,4-trimethylstyrene and the like And vinyl aromatic hydrocarbon monomers of These may be used alone or in combination of two or more. Among them, styrene is preferred.

  Examples of the conjugated diene component constituting the component B include 1,3-butadiene, isoprene, 1,3-pentadiene, 2,3-dimethylbutadiene, 2-phenyl-1,3-butadiene, myrcene, farnesene and the like. Be These may be used alone or in combination of two or more. Among these, 1,3-butadiene is preferable.

  Examples of component B include styrene-butadiene copolymer, styrene-isoprene copolymer, and styrene-myrcene copolymer.

  Content with respect to 100 mass parts of rubber components of component B is 10 mass parts or more, 15 mass parts or more are preferable, and 20 mass parts or more are more preferable. If the amount is less than 10 parts by mass, grip performance may be insufficient. Moreover, content with respect to 100 mass parts of rubber components of component B is 200 mass parts or less, 180 mass parts or less are preferable, and 150 mass parts or less are more preferable. If it exceeds 200 parts by mass, the processability and the abrasion resistance may be deteriorated.

  The absolute value of the difference between the aromatic vinyl content of component A and the aromatic vinyl content of component B is (1) less than 15 or (2) the aromatic vinyl content of component A is component B And the difference between the aromatic vinyl content of component A and the absolute value of the aromatic vinyl content of component B is less than 20. Otherwise, the compatibility between the two components may be degraded, and bleeding may occur. In the case of the above (1), the absolute value is preferably 10 or less. In the case of the above (2), the absolute value is preferably 15 or less. In any case, the lower limit of the absolute value is not particularly limited, and 0 is most preferable.

  Component A and Component B are both preferably polymers polymerized from at least one or more of monomers having a conjugated diene structure, from the viewpoint of the compatibility between Component A and Component B.

  Component C is a resin which has a freezing point of 25 ° C. or higher and is solid at 25 ° C. If the freezing point is less than 25 ° C., it may become liquid at room temperature, so that sufficient grip performance may not be obtained. Component C includes styrene resin, terpene resin, coumarone indene resin, phenol resin and the like. Component C may use only 1 type and may use it in combination of 2 or more type.

  Component C is preferably an organic substance having a cyclic conjugated diene structure, since component A is particularly good in compatibility with component C when component A is SBR, and bloom can be further suppressed. It is preferable that it is an organic substance which has a formula conjugated diene structure.

  Content with respect to 100 mass parts of rubber components of component C is 5 mass parts or more, and 10 mass parts or more are preferable. If the amount is less than 5 parts by mass, sufficient grip performance may not be obtained. Further, the upper limit of the content of component C with respect to 100 parts by mass of the rubber component is preferably 50 parts by mass or less, and more preferably 40 parts by mass or less, from the viewpoint of maintaining the hardness of the rubber.

  Component D is a liquid plasticizer having a freezing point of 20 ° C. or less. When the freezing point exceeds 20 ° C., the rubber composition tends not to be sufficiently plasticized.

  The viscosity measured by a B-type viscometer at 25 ° C. of the component D is less than 100,000, and preferably 50,000 or less. If the viscosity is 100,000 or more, there is a possibility that the rubber composition can not be provided with sufficient plasticity. Further, the lower limit of the viscosity measured by a B-type viscometer at 25 ° C. of the component D does not have a lower limit in particular, and it is sufficient if the plasticity is given.

  The flash point of the component D is preferably 200 ° C. or higher because it can suppress ignition during processing.

  As component D, aromatic oil, mineral oil, phosphate ester plasticizer, aliphatic ester plasticizer and the like can be mentioned. Component D may be used alone or in combination of two or more.

  Content with respect to 100 mass parts of rubber components of component D is 5 mass parts or more, and 10 mass parts or more are preferable. If the amount is less than 5 parts by mass, sufficient plasticity may not be imparted. The upper limit of the content of component D with respect to 100 parts by mass of the rubber component is preferably 45 parts by mass or less, more preferably 40 parts by mass or less, from the viewpoint of maintaining sufficient rigidity of the rubber.

  The total content of the component B, the component C and the component D is 80 parts by mass or more, preferably 85 parts by mass or more. If the amount is less than 80 parts by mass, grip performance may be insufficient. Further, the upper limit of the total content of the component B, the component C and the component D is not particularly limited as long as the effects of the present invention are not impaired.

  That is, the absolute value of the difference between the aromatic vinyl content of Component A and the aromatic vinyl content of Component B is less than 15, or the aromatic vinyl content of Component A of Component B is Component B. And the difference between the aromatic vinyl content of component A and the absolute value of the aromatic vinyl content of component B is less than 20, and at least 5 parts by weight of component C and at least 5 parts by weight of component D By containing component B, component C and component D in a total amount of 80 parts by mass or more, bleed of component B and bloom of component D can be suppressed, and high grip performance and abrasion resistance can be exhibited. .

  In particular, as the reason for the improvement of the grip performance, the inclusion of the component B sufficiently increases the ability of the rubber to follow the road surface at low temperatures, and the inclusion of the component C increases the tackiness of the rubber at high temperatures It is thought that the trackability to the road surface is increased. Further, as the reason why the bleed of component B and the bloom of component C are suppressed, the compatibility between component A and component B is high, and component D improves the compatibility between component A, component B and component C. It is thought that it is because

  In the rubber composition, in addition to the above components, other components generally used in the production of the rubber composition, such as fillers, silane coupling agents, softeners, stearic acid, zinc oxide, various antioxidants Waxes, vulcanizing agents, vulcanization accelerators and the like can be appropriately blended.

  As the filler, carbon black, silica, calcium carbonate, alumina, clay, talc and the like can be mentioned. From the viewpoint of wet grip performance, it is preferable to contain carbon black and / or silica, and carbon black is more preferable.

The nitrogen adsorption specific surface area (N ₂ SA) of carbon black is preferably 80 m ² / g or more, more preferably 100 m ² / g or more, and still more preferably 200 m ² / g or more from the viewpoint of grip performance and abrasion resistance. Further, N ₂ SA of carbon black is preferably 280 m ² / g or less from the viewpoint of dispersibility and abrasion resistance. Incidentally, N ₂ SA of the carbon black in the present specification is a value measured according to the method A of JIS K6217.

  From the viewpoint of wear resistance, the content of carbon black is preferably 10 parts by mass or more, and more preferably 15 parts by mass or more, with respect to 100 parts by mass of the rubber component. The content of carbon black is preferably 200 parts by mass or less from the viewpoint of processability.

  The silica is not particularly limited, and examples thereof include dry method silica (anhydrous silicic acid), wet method silica (hydrous silicic acid) and the like, but wet method silica is preferable because it has many silanol groups.

The nitrogen adsorption specific surface area (N ₂ SA) of silica is preferably 80 m ² / g or more, more preferably 100 m ² / g or more, and 110 m ² / g from the viewpoint of elongation at break and durability. It is more preferable that it is more than. The N ₂ SA of the silica, fuel economy, in view of workability (sheet rolling property), preferably at 250 meters ² / g or less, more preferably at most 235m ² / g, 220m ² / More preferably, it is g or less. The nitrogen adsorption specific surface area of silica is a value measured by the BET method in accordance with ASTM D3037-81.

  The content in the case of containing silica is preferably 5 parts by mass or more, and 7 parts by mass or more, with respect to 100 parts by mass of the rubber component, because the effect of containing silica is sufficiently obtained. It is more preferable that Moreover, from a viewpoint of processability, 40 mass parts or less are preferable, and 35 mass parts or less are more preferable.

  Silica is preferably used in combination with a silane coupling agent. As the silane coupling agent, any silane coupling agent conventionally used in combination with silica can be used in the rubber industry, for example, bis (3-triethoxysilylpropyl) disulfide, bis (3-triethoxy) Sulfide type such as silylpropyl) tetrasulfide, 3-mercaptopropyltrimethoxysilane, NXT-Z100 manufactured by Momentive, mercapto type such as NXT-Z45, NXT (silane coupling agent having a mercapto group), vinyltriethoxysilane And vinyl, amino group such as 3-aminopropyltriethoxysilane, glycidoxy group such as γ-glycidoxypropyltriethoxysilane, nitro group such as 3-nitropropyltrimethoxysilane, 3-chloropropyl trimethoxysilane Down like chloro systems such. 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 a silane coupling agent is 4.0 parts by mass or more because an effect of improving the filler dispersibility and a reduction in viscosity etc. can be obtained. Preferably, it is more preferably 6.0 parts by mass or more. In addition, the content of the silane coupling agent is preferably 12 parts by mass or less, and 10 parts by mass or less, because sufficient coupling effect, silica dispersion effect can not be obtained, and the reinforcing property is reduced. Is more preferred.

  The anti-aging agent is not particularly limited, and those used in the field of rubber can be used, and examples thereof include quinoline-based, quinone-based, phenol-based and phenylene diamine-based anti-aging agents.

  In the case of containing an antiaging agent, the content relative to 100 parts by mass of the rubber component is preferably 0.5 parts by mass or more, and more preferably 0.8 parts by mass or more. In addition, the content of the antiaging agent is preferably 2.0 parts by mass or less, more preferably 1.5 parts by mass or less, from the viewpoint of dispersibility of the filler, elongation at break, and kneading efficiency. Part or less is more preferable.

  As the vulcanizing agent, sulfur-containing compounds such as sulfur and caprolactam disulfide are used. Examples of sulfur as a vulcanizing agent include powdered sulfur, precipitated sulfur, colloidal sulfur, insoluble sulfur, oil-treated sulfur and the like. These can be used alone or in combination of two or more.

  The content relative to 100 parts by mass of the rubber component in the case of containing a vulcanizing agent is preferably 0.5 parts by mass or more, and more preferably 0.6 parts by mass or more from the viewpoint of a favorable vulcanization reaction. In addition, the content of sulfur is preferably 3 parts by mass or less, and more preferably 2 parts by mass or less from the viewpoint of grip performance and abrasion resistance.

  Examples of the vulcanization accelerator include compounds of guanidine type, aldehyde-amine type, aldehyde-ammonia type, thiazole type, sulfenamide type, thiourea type, thiuram type, dithiocarbamate type, and zandate type. Among them, a vulcanization accelerator having a benzothiazolyl sulfide group is preferable because the effects of the present invention can be suitably obtained.

  As a vulcanization accelerator having a benzothiazolyl sulfide group, N-tert-butyl-2-benzothiazolylsulfenamide (TBBS), N-cyclohexyl-2-benzothiazolylsulfenamide (CBS), N , N-dicyclohexyl-2-benzothiazolylsulfenamide (DCBS), N, N-diisopropyl-2-benzothiazolesulfenamide, N, N-di (2-ethylhexyl) -2-benzothiazolylsulfenamide (BEHZ), N, N-di (2-methylhexyl) -2-benzothiazolylsulfenamide (BMHZ), N-ethyl-N-t-butylbenzothiazole-2-sulfenamide (ETZ), etc. Sulfenamide vulcanization accelerators, N-tert-butyl-2-benzothiazolylsulfene De (TBSI), di-2-benzothiazolyl disulfide (DM), and the like.

  The content with respect to 100 parts by mass of the rubber component in the case of containing a vulcanization accelerator is preferably 0.5 parts by mass or more, and preferably 1.0 parts by mass or more from the viewpoint of securing a sufficient vulcanization rate. Further, the content of the vulcanization accelerator is preferably 10 parts by mass or less, and more preferably 5 parts by mass or less, from the viewpoint of suppressing bloom.

  The rubber composition according to the present embodiment can be manufactured by a general method. For example, after kneading the components other than the crosslinking agent and the vulcanization accelerator among the above-mentioned components with a known kneader used in general rubber industry such as Banbury mixer, kneader, open roll, etc. A cross-linking agent and a vulcanization accelerator may be added and further kneaded, followed by vulcanization.

  The rubber composition according to this embodiment is a rubber composition which is excellent in processability, abrasion resistance and grip performance in a well-balanced manner and in which bleeding is suppressed. Therefore, it is used for the tread, sidewall, clinch etc. It is preferable to use for a tread, and it is further preferable to use for high performance tire treads, such as a competition tire.

  The tire according to the present embodiment can be manufactured by the usual method using the rubber composition. That is, the rubber composition prepared by blending the above-mentioned compounding agent with respect to the rubber component as required is extruded according to the shape of the tire member, and bonded together with other tire members on a tire molding machine. By molding by a method, an unvulcanized tire is formed, and the unvulcanized tire is heated and pressurized in a vulcanizer to produce a tire.

The following may be mentioned as preferred embodiments.
[1] A rubber containing 60% by mass or more of a conjugated diene polymer (component A) having a weight average molecular weight of 1.5 × 10 ^{5 to} 3.0 × 10 ⁶ and an aromatic vinyl content of 60% by mass or less Per 100 parts by mass of the component
Weight average molecular weight is 1.0 × 10 ^{3 to} 1.0 × 10 ⁵ , aromatic vinyl content is 70% by mass or less, vinyl bond content of conjugated diene portion is 20 to 70%, hydrogenation Of 10 to 200 parts by mass of a conjugated diene polymer (component B) having a viscosity of 56% or more and a viscosity of 100,000 or more measured by a B-type viscometer at 25 ° C.
5 parts by mass or more of a resin (component C) which has a freezing point of 25 ° C. or higher and is solid at 25 ° C.,
A rubber composition containing 5 parts by mass or more of a liquid plasticizer (component D) having a freezing point of 20 ° C. or less and a viscosity measured by a B-type viscometer at 25 ° C. of less than 100,000.
The total content of component B, component C and component D is 80 parts by mass or more,
The absolute value of the difference between the aromatic vinyl content of Component A and the aromatic vinyl content of Component B is less than 15, or the aromatic vinyl content of Component A is greater than the aromatic vinyl content of Component B A rubber composition having a large difference in absolute value between the aromatic vinyl content of component A and the aromatic vinyl content of component B is less than 20,
[2] The rubber composition according to the above [1], wherein the vinyl bond content of the conjugated diene portion of the component A is 20 to 60%,
[3] The rubber composition according to the above [1] or [2], wherein Component A and Component B are both polymers polymerized from at least one or more of monomers having a conjugated diene structure.
[4] The rubber composition according to any one of the above [1] to [3], wherein Component C is an organic substance having a cyclic conjugated diene structure,
[5] The rubber composition according to any one of the above [1] to [4], wherein the flash point of the component D is 200 ° C. or higher,
[6] The rubber composition according to any one of the above [1] to [5], further containing a filler,
[7] A tire having a tire member made of the rubber composition according to any one of the above [1] to [6].

  The present invention will be described based on examples, but the present invention is not limited to the examples.

Hereinafter, various medicines used in Examples and Comparative Examples are collectively shown.
Conjugated diene polymers 1 to 6: conjugated diene polymers 1 to 6 prepared by the method for producing conjugated diene polymers 1 to 6 described below
Resin 1: YS resin TO 125 (solidifying point: 65 ° C., terpene resin, no hetero atom) manufactured by Yasuhara Chemical Co., Ltd.
Resin 2: Clearon M 125 (solidifying point: 65 ° C., hydrogenated terpene resin, no hetero atom) manufactured by Yasuhara Chemical Co., Ltd.
Resin 3: YS Polystar T115 (solidifying point: 55 ° C., terpene phenolic resin, with hetero atoms) manufactured by Yasuhara Chemical Co., Ltd.
Resin 4: YS Polystar UH115 (solidifying point: 55 ° C., hydrogenated terpene phenol resin, with hetero atoms) manufactured by Yasuhara Chemical Co., Ltd.
Liquid plasticizer: TOP8 (tris (2-ethylhexyl) phosphate) manufactured by Daihachi Chemical Industry Co., Ltd. (Freezing point: -70 ° C or less, viscosity (B type, 25 ° C): 51, flash point: 204 ° C)
Carbon black: S East 9 (N ₂ SA: 142 m ² / g) made of Tokai Carbon
Stearic acid: Stearic acid "Tsubaki" manufactured by NOF Corporation
Zinc oxide: fine particle zinc oxide (average primary particle size: 100 nm)
Anti-aging agent: Antigen 6C manufactured by Sumitomo Chemical Co., Ltd.
Sulfur: Powdered sulfur vulcanization accelerator manufactured by Karuizawa Smelter Co., Ltd .: Noccellar CZ manufactured by Ouchi New Chemical Co., Ltd.

Hereinafter, various chemicals used in the method for producing conjugated diene polymers 1 to 6 are collectively shown.
Hexane: anhydrous hexane isopropanol manufactured by Kanto Chemical Co., Ltd. special grade isopropanol TMEDA manufactured by Kanto Chemical Co., Ltd. tetramethylethylenediamine butadiene manufactured by Kishida Chemical Co., Ltd. 1,3-butadiene styrene manufactured by Takachiho Chemical Industry Co., Ltd. Styrene manufactured by Wako Pure Chemical Industries, Ltd.

Method of Producing Conjugated Diene Polymer 1 Into a dry, nitrogen-substituted, 3 L pressure-resistant stainless steel polymerization vessel, 1800 g of hexane, 150 g of butadiene, and 50 g of styrene were charged together with 0.22 mmol of TMEDA. Next, a small amount of n-bryllithium / hexane solution was charged into the polymerization vessel as a scavenger in order to previously detoxify impurities affecting the deactivation of the polymerization initiator. Furthermore, after adding n-butyllithium / hexane solution (1.17 mmol as content of n-butyllithium), the polymerization reaction was performed at 50 degreeC for 3 hours. After 3 hours, 1.15 ml of 1 M isopropanol / hexane solution was added dropwise to complete the reaction. Next, the polymerization solution was evaporated at room temperature for 24 hours, and further dried under reduced pressure at 80 ° C. for 24 hours to obtain conjugated diene polymer 1. The polymerization conversion was about 100%.

Method of Producing Conjugated Diene Polymer 2 The procedure of the method of producing conjugated diene polymer 1 was repeated except that the amount was changed to 130 g of butadiene and 70 g of styrene, to obtain a conjugated diene polymer 2. The polymerization conversion was about 100%.

Method of Producing Conjugated Diene Polymer 3 The procedure of the method of producing conjugated diene polymer 1 was repeated except that 110 g of butadiene and 90 g of styrene were used to obtain conjugated diene polymer 3. The polymerization conversion was about 100%.

Method of Producing Conjugated Diene Polymer 4 Into a dry, nitrogen-substituted, 3 L pressure-resistant stainless steel polymerization vessel, 1800 g of hexane, 140 g of butadiene, and 60 g of styrene were charged together with 0.22 mmol of TMEDA. Next, a small amount of n-bryllithium / hexane solution was charged into the polymerization vessel as a scavenger in order to previously detoxify impurities affecting the deactivation of the polymerization initiator. Furthermore, after adding n-butyllithium / hexane solution (1.17 mmol as content of n-butyllithium), the polymerization reaction was performed at 50 degreeC for 3 hours. After 3 hours, 2 L of 1 M isopropanol / hexane solution is added dropwise to complete the reaction, and after removing the supernatant, the precipitate is evaporated at room temperature for 24 hours and further dried under reduced pressure at 80 ° C. for 24 hours. I got Add 200 g of unhydrogenated substance, 300 g of THF, and 10 g of 10% palladium carbon in a pressure container, replace with nitrogen, replace with hydrogen so that the pressure is 5.0 kg / cm ² , repeat hydrogen replacement until hydrogen absorption stops After reaction at 80 ° C., the reaction solution was filtered to remove the catalyst, and then the filtrate was evaporated at room temperature for 24 hours and further dried under reduced pressure at 80 ° C. for 24 hours to obtain conjugated diene polymer 4 .

Method of Producing Conjugated Diene Polymer 5 The procedure of the method of producing conjugated diene polymer 4 was repeated except that it was changed to 120 g of butadiene and 80 g of styrene, to obtain conjugated diene polymer 5. The polymerization conversion was about 100%.

Method of Producing Conjugated Diene Polymer 6 The procedure of the method of producing conjugated diene polymer 4 was repeated except that 100 g of butadiene and 100 g of styrene were changed to obtain conjugated diene polymer 6. The polymerization conversion was about 100%.

  The weight average molecular weight (Mw) of the conjugated diene polymers 1 to 6 is a value measured using a gel permeation chromatograph (GPC, GPC-8000 series manufactured by Tosoh Corp.) and a differential refractometer as a detector. In terms of standard polystyrene.

  The aromatic vinyl content of the conjugated diene polymers 1 to 6 was calculated according to JIS-K-6239. The vinyl bond amount of the conjugated diene portion of each of the conjugated diene polymers 1 to 6 was calculated in accordance with JIS-K-6239.

  The hydrogenation rates of the conjugated diene polymers 4 to 6 are based on butadiene units obtained by measuring proton NMR at 25 ° C. using a JOEL JNM-A 400 NMR instrument at each sample before and after the hydrogenation reaction. It was calculated from the decrease rate of methylene proton of vinyl bond.

  Table 1 shows various properties of conjugated diene polymers 1 to 6.

Examples and Comparative Examples According to the formulation shown in Tables 2 to 5, using a 1.7 L internal Banbury mixer, the chemicals other than sulfur and vulcanization accelerator are mixed for 5 minutes until reaching 150 ° C. and mixed. I got a paste. Next, using an open roll, sulfur and a vulcanization accelerator were added to the obtained kneaded product, and kneaded for 3 minutes at 80 ° C. to obtain an unvulcanized rubber composition. Furthermore, the resulting unvulcanized rubber composition was press-cured for 30 minutes under the condition of 150 ° C. to obtain a vulcanized rubber composition.

  The unvulcanized rubber composition is extruded into a shape of a tire tread by an extruder equipped with a die having a predetermined shape, and is bonded together with other tire members to form an unvulcanized tire, and the condition of 170 ° C. The test tire (size: 195 / 65R15) was manufactured by press curing for 12 minutes under.

  The following evaluation was performed about the obtained unvulcanized rubber composition, a vulcanized rubber composition, and the tire for a test. The evaluation results are shown in Table 1.

Tensile test The tensile strength was measured according to JIS-K-6251. A result is shown by the index which makes the tensile strength of comparative example 1 100. The larger the index, the higher the tensile strength.

Processability evaluation The adhesion level to the Banbury mixer and open roll of the rubber composition at the time of kneading was evaluated according to the following criteria.
○: There is almost no adhesion and no problem.
Fair: close contact, takes longer to discharge rubber than "o".
X: The adhesion is bad, and it takes longer to discharge the rubber than “Δ”.

Evaluation of Bleeding Properties The surface of the test tire was observed, and the degree of the oily bleeding component was visually confirmed.
○: No bleed △: Slight bleed × ×: Bleeding intense

Grip performance test Each test tire was mounted on all wheels of a domestic FR car with a displacement of 2000 cc, and was run on a dry asphalt road test course. The test driver evaluated the stability of the control at the time of steering. A result is shown by the index which makes evaluation of comparative example 1 100. The larger the index, the higher the initial grip performance.

Wear resistance test Each test tire is mounted on all wheels of a domestic FR car with a displacement of 2000 cc, and the groove depth of the tire tread portion after a traveling distance of 8000 km is measured, and the traveling distance when the tire groove depth decreases by 1 mm I asked for. The result is indicated by an index where the traveling distance when the tire groove of Comparative Example 1 decreases by 1 mm is 100. The larger the index, the better the wear resistance.

  From the results of Tables 2 to 5, according to the rubber composition of the present invention and the tire having a tread constituted by the rubber composition, the processability, the abrasion resistance and the grip performance were excellent in a well-balanced manner, and bleeding was suppressed. It turns out that it is a rubber composition and a tire.

Claims (7)

100 parts by mass of a rubber component containing 60% by mass or more of a conjugated diene polymer (component A) having a weight average molecular weight of 1.5 × 10 ^{5 to} 3.0 × 10 ⁶ and an aromatic vinyl content of 60% by mass or less For the department,
Weight average molecular weight is 1.0 × 10 ^{3 to} 1.0 × 10 ⁵ , aromatic vinyl content is 70% by mass or less, vinyl bond content of conjugated diene portion is 20 to 70%, hydrogenation Of 10 to 200 parts by mass of a conjugated diene polymer (component B) having a viscosity of 56% or more and a viscosity of 100,000 or more measured by a B-type viscometer at 25 ° C.
5 parts by mass or more of a resin (component C) which has a freezing point of 25 ° C. or higher and is solid at 25 ° C.,
A rubber composition containing 5 parts by mass or more of a liquid plasticizer (component D) having a freezing point of 20 ° C. or less and a viscosity measured by a B-type viscometer at 25 ° C. of less than 100,000.
The total content of component B, component C and component D is 80 parts by mass or more,
The absolute value of the difference between the aromatic vinyl content of Component A and the aromatic vinyl content of Component B is less than 15, or the aromatic vinyl content of Component A is greater than the aromatic vinyl content of Component B A rubber composition having a large difference in absolute value between the aromatic vinyl content of component A and the aromatic vinyl content of component B is less than 20. The rubber composition according to claim 1, wherein the vinyl bond content of the conjugated diene portion of component A is 20 to 60%. The rubber composition according to claim 1 or 2, wherein Component A and Component B are both polymers polymerized from at least one or more of monomers having a conjugated diene structure. The rubber composition according to any one of claims 1 to 3, wherein Component C is an organic substance having a cyclic conjugated diene structure. The rubber composition according to any one of claims 1 to 4, wherein the flash point of component D is 200 ° C or higher. Furthermore, the rubber composition of any one of Claims 1-5 containing a filler. The tire which has a tire member comprised by the rubber composition according to any one of claims 1 to 6.