JP5294047B2 - Rubber composition for tread, tread and tire - Google Patents

Description

  The present invention relates to a rubber composition for a tread, a tread and a tire, and in particular, a rubber composition for a tread capable of producing a tire excellent in rolling resistance, vehicle handling stability, wet skid performance and wear resistance, The present invention relates to a tread formed using a rubber composition for a tread and a tire manufactured using the tread.

  Conventionally, the fuel consumption of a vehicle has been reduced by reducing tire rolling resistance and suppressing heat generation. In recent years, there has been an increasing demand for reducing fuel consumption of vehicles by using tires, and there is a particularly large demand for reducing fuel consumption by improving treads that have a high occupation ratio among tire members.

  As a method of making a tire tread low heat build-up, a method of reducing the amount of reinforcing filler in the rubber composition forming the tread is known. In this case, the hardness of the rubber composition is low. As a result, the tread of the tire is softened, resulting in a problem that the steering stability of the vehicle and the wet skid performance of the tire are lowered.

Therefore, as a method for solving this problem, silica or the like has been used for the filler. A rubber composition for a tread in which a composite material of starch and a plasticizer is blended together with silica has also been proposed (see, for example, Patent Document 1). A rubber formed by vulcanizing this rubber composition There is a problem that the tire having the tread made of is not sufficiently wear-resistant.
JP 2003-192832 A

  In view of the above circumstances, an object of the present invention is to provide a rubber composition for a tread capable of producing a tire excellent in rolling resistance, vehicle handling stability, wet skid performance and wear resistance, and the rubber composition for the tread. It is providing the tread formed using the thing and the tire manufactured using the tread.

The present invention includes a rubber component composed of styrene-butadiene rubber , a composite material of starch and a plasticizer, a first silica having an average primary particle diameter of 20 nm or more, and a second silica having an average primary particle diameter of less than 20 nm. The composite material is contained in an amount of 1 to 30 parts by mass with respect to 100 parts by mass of the rubber component, and the first silica is 10 to 30 parts by mass with respect to 100 parts by mass of the rubber component. parts included below, the second silica is included 5 parts by mass or more with respect to 100 parts by mass of the rubber component, the total content of the first silica and the second silica per 100 parts by mass of the rubber component The tread rubber composition is 15 parts by weight or more and 150 parts by weight or less.

Moreover, this invention is a tread formed using said rubber composition for treads.
Furthermore, this invention is a tire manufactured using said tread.

  According to the present invention, a rubber composition for a tread capable of producing a tire excellent in rolling resistance, vehicle handling stability, wet skid performance and wear resistance, and formed using the rubber composition for a tread. A tread and a tire manufactured using the tread can be provided.

  Embodiments of the present invention will be described below. In the drawings of the present invention, the same reference numerals represent the same or corresponding parts.

<Rubber component>
Examples of the rubber component used in the present invention include natural rubber (NR), polyisoprene synthetic rubber (IR), polybutadiene rubber (BR), styrene-butadiene rubber (SBR), acrylonitrile-butadiene rubber (NBR), and chloroprene rubber. Diene rubbers such as (CR), butyl rubber (IIR), and styrene-isoprene-butadiene copolymer rubber (SIBR) can be used. These diene rubbers may be used alone or in combination of two or more. Among these, styrene-butadiene rubber (SBR) is preferably used as the rubber component in consideration of the balance between rolling resistance and wet skid performance of a tire having a tread formed using the rubber composition for a tread of the present invention.

<Silica>
In the present invention, the processability of the tread rubber composition of the present invention is improved by mixing two types of silica having different average primary particle sizes into the rubber component, and the tread rubber composition of the present invention. This improves the wear resistance of a tire having a tread formed by using.

  That is, in the present invention, the processability of the rubber composition for a tread of the present invention is improved by mixing the first silica having an average primary particle size of 20 nm or more, and the second primary particle having an average primary particle size of less than 20 nm. By mixing silica, the wear resistance of a tire having a tread formed using the rubber composition for a tread of the present invention is improved.

  Here, the average primary particle diameter of the first silica is more preferably 25 nm or more. When the average primary particle diameter of the first silica is 25 nm or more, the rolling resistance of a tire having a tread formed using the rubber composition for a tread of the present invention tends to be further reduced.

  The average primary particle diameter of the second silica is more preferably less than 18 nm. When the average primary particle diameter of the second silica is less than 18 nm, the rubber hardness of the tire having the tread formed using the rubber composition for a tread of the present invention is improved, and the wear resistance of the tire is further improved. Tend to.

  In the present invention, the “average primary particle diameter” means the average value of the longest diameters (major diameters) among the particle diameters of particles (the length of a straight line connecting any two points on the periphery of the particles). Say.

  Further, the “average primary particle diameter” in the present invention can be measured by a TEM (transmission electron microscope).

  Moreover, content of 1st silica is 10 mass parts or more with respect to 100 mass parts of said rubber components. When the content of the first silica is less than 10 parts by mass with respect to 100 parts by mass of the rubber component, the effect of mixing the first silica cannot be obtained, and the rubber composition for treads of the present invention is not obtained. Workability cannot be improved.

  Moreover, content of the 2nd silica is 5 mass parts or more with respect to 100 mass parts of said rubber components. When the content of the second silica is less than 5 parts by mass with respect to 100 parts by mass of the rubber component, the effect of mixing the second silica is not obtained, and the rubber composition for treads of the present invention is used. The wear resistance of a tire having a tread formed by using the tire cannot be improved.

  Further, the total content of the first silica and the second silica is 15 parts by mass or more and 150 parts by mass or less with respect to 100 parts by mass of the rubber component. When the total content of the first silica and the second silica is less than 15 parts by mass with respect to 100 parts by mass of the rubber component, two types of silica having different average primary particle sizes (the first silica and When the effect of mixing the second silica) is not obtained and the amount exceeds 150 parts by mass, it is difficult to disperse the first silica and the second silica into the rubber component, and the tread of the present invention is used. The processability of the rubber composition is reduced.

  As the first silica and the second silica used in the present invention, conventionally known dry silica, wet silica and the like can be used without any particular limitation.

<Composite material of starch and plasticizer>
The composite material of starch and plasticizer used in the present invention is a mixture of starch and plasticizer. Generally, when starch and plasticizer are mixed, it is between starch and plasticizer. It is believed that relatively strong chemical and / or physical interactions exist.

  Here, the starch is usually a sugar chain composed of a repeating unit of amylose (an anhydroglucopyranose unit bonded by a glucoside bond) and a repeating unit of amylopectin constituting a branched chain structure. Specific examples include storage polysaccharides derived from plants such as corn, potato, rice and wheat.

  Moreover, a plasticizer is used in order to reduce the softening point of starch and facilitate dispersion into the rubber component. Therefore, it is preferable to have a melting point sufficiently lower than the softening point of starch. For example, a plasticizer having a melting point of preferably less than 180 ° C, more preferably less than 160 ° C is used.

  Examples of such plasticizers include ethylene-vinyl alcohol copolymer, ethylene-acetate-vinyl alcohol terpolymer, ethylene-vinyl acetate copolymer, ethylene-glycidyl acrylate copolymer, ethylene-anhydrous Examples include maleic acid copolymer, cellulose acetate, and ester condensate of dibasic organic acid and diol. One or more plasticizers may be contained in the composite material of starch and plasticizer.

  Content of the composite material of the starch and plasticizer used for this invention is 1 to 30 mass parts with respect to 100 mass parts of said rubber components. When the content of the composite material of starch and plasticizer is less than 1 part by mass with respect to 100 parts by mass of the rubber component, a tire wet having a tread formed using the tread rubber composition of the present invention When the skid performance deteriorates and exceeds 30 parts by mass, the wear resistance of the tire having a tread formed using the rubber composition for a tread of the present invention is deteriorated.

  The content of the composite material of starch and plasticizer used in the present invention is preferably 2 parts by mass or more and 20 parts by mass or less, preferably 5 parts by mass or more and 15 parts by mass or less with respect to 100 parts by mass of the rubber component. It is more preferable that the amount is not more than parts. When the content of the composite material of starch and plasticizer is 2 parts by mass or more and 20 parts by mass or less, particularly 5 parts by mass or more and 15 parts by mass or less with respect to 100 parts by mass of the rubber component, Both wet skid performance and wear resistance of a tire having a tread formed using the rubber composition for a tread of the invention tend to be improved.

  The starch content in the composite of starch and plasticizer used in the present invention is preferably 50 parts by mass or more and 400 parts by mass or less, and 100 parts by mass or more and 200 parts by mass or less with respect to 100 parts by mass of the plasticizer. It is more preferable that When the content of starch in the composite material is 50 parts by mass or more and 400 parts by mass or less, particularly 100 parts by mass or more and 200 parts by mass or less with respect to 100 parts by mass of the plasticizer, the wet skid performance and There is a tendency that a tire excellent in wear resistance can be produced.

<Other ingredients>
In addition to the above materials, the rubber composition for a tread of the present invention includes, for example, a silane coupling agent, oil, zinc oxide, stearic acid, anti-aging agent, wax, sulfur generally used in the tire industry. Or various materials, such as a vulcanization accelerator, may be mix | blended suitably.

  Here, conventionally known silane coupling agents can be used, for example, bis (3-triethoxysilylpropyl) tetrasulfide, bis (2-triethoxysilylethyl) tetrasulfide, bis (3 -Trimethoxysilylpropyl) tetrasulfide, bis (2-trimethoxysilylethyl) tetrasulfide, bis (3-triethoxysilylpropyl) trisulfide, bis (3-trimethoxysilylpropyl) trisulfide, bis (3-tri Ethoxysilylpropyl) disulfide, bis (3-trimethoxysilylpropyl) disulfide, 3-trimethoxysilylpropyl-N, N-dimethylthiocarbamoyl tetrasulfide, 3-triethoxysilylpropyl-N, N-dimethylthiocarbamoylte Rasulfide, 2-triethoxysilylethyl-N, N-dimethylthiocarbamoyl tetrasulfide, 2-trimethoxysilylethyl-N, N-dimethylthiocarbamoyl tetrasulfide, 3-trimethoxysilylpropylbenzothiazolyl tetrasulfide, 3 -Sulfide systems such as triethoxysilylpropyl benzothiazole tetrasulfide, 3-triethoxysilylpropyl methacrylate monosulfide, 3-trimethoxysilylpropyl methacrylate monosulfide, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, Mercapto series such as 2-mercaptoethyltrimethoxysilane, 2-mercaptoethyltriethoxysilane, vinyltriethoxysilane, vinyltrimethoxysilane Vinyl-based, 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3- (2-aminoethyl) aminopropyltriethoxysilane, 3- (2-aminoethyl) aminopropyltrimethoxysilane, etc. Glycidoxy series such as γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, 3 -Nitropropyl trimethoxysilane, 3-nitropropyl triethoxysilane and other nitro compounds, 3-chloropropyltrimethoxysilane, 3-chloropropyltriethoxysilane, 2-chloroethyltrimethoxysilane, 2-chloroethyltriethoxysilane Chloro such as And the like. In addition, said silane coupling agent may be used independently and may be used in combination of 2 or more type.

  Moreover, conventionally well-known thing can be used as oil, For example, process oil, vegetable oil, or a mixture thereof etc. can be used. As the process oil, for example, paraffinic process oil, naphthenic process oil, aromatic process oil, or the like can be used. As vegetable oils and fats, for example, 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, beet flower oil, Sesame oil, olive oil, sunflower oil, palm kernel oil, coconut oil, jojoba oil, macadamia nut oil, tung oil, and the like can be used.

  Moreover, as a zinc oxide, a conventionally well-known thing can be used, for example, Mitsui Metal Mining Co., Ltd. zinc oxide etc. can be used.

  Moreover, as stearic acid, a conventionally well-known thing can be used, for example, a cocoon etc. by Nippon Oils and Fats Co., Ltd. can be used.

  As the anti-aging agent, conventionally known ones can be used. For example, Antigen 6C (N- (1,3-dimethylbutyl) -N′-phenyl-p-phenylene manufactured by Sumitomo Chemical Co., Ltd.). Diamine) and the like can be used.

  Moreover, as a wax, a conventionally well-known thing can be used, for example, Onouchi Shinsei Chemical Co., Ltd. sun knock wax etc. can be used.

  Moreover, conventionally well-known thing can be used as sulfur, for example, powder sulfur etc. by Karuizawa sulfur Co., Ltd. can be used.

  As the vulcanization accelerator, conventionally known vulcanization accelerators can be used. For example, sulfenamide, thiazole, thiuram, thiourea, guanidine, dithiocarbamic acid, aldehyde-amine, or aldehyde- Those containing at least one of ammonia-based, imidazoline-based, or xanthate-based vulcanization accelerators can be used. Examples of the sulfenamide system include CBS (N-cyclohexyl-2-benzothiazylsulfenamide), TBBS (N-tert-butyl-2-benzothiazylsulfenamide), N, N′-dicyclohexyl-2. -Sulfenamide compounds such as benzothiazylsulfenamide, N-oxydiethylene-2-benzothiazylsulfenamide, and N, N'-diisopropyl-2-benzothiazolesulfenamide can be used. . Examples of the thiazole type include MBT (2-mercaptobenzothiazole), MBTS (dibenzothiazyl disulfide), sodium salt of 2-mercaptobenzothiazole, zinc salt, copper salt, cyclohexylamine salt, 2- (2,4-dinitro). Thiazole compounds such as phenyl) mercaptobenzothiazole and 2- (2,6-diethyl-4-morpholinothio) benzothiazole can be used. Examples of thiurams include TMTD (tetramethyl thiuram disulfide), tetraethyl thiuram disulfide, tetramethyl thiuram monosulfide, dipentamethylene thiuram disulfide, dipentamethylene thiuram monosulfide, dipentamethylene thiuram tetrasulfide, dipentamethylene thiuram hexasulfide. Further, thiuram compounds such as tetrabutylthiuram disulfide and pentamethylenethiuram tetrasulfide can be used. Examples of thiourea compounds that can be used include thiourea compounds such as thiocarbamide, diethylthiourea, dibutylthiourea, trimethylthiourea, and diortolylthiourea. Examples of guanidine-based compounds include guanidine-based compounds such as diphenylguanidine, diortolylguanidine, triphenylguanidine, orthotolylbiguanide, and diphenylguanidine phthalate. Examples of dithiocarbamate include zinc ethylphenyldithiocarbamate, zinc butylphenyldithiocarbamate, sodium dimethyldithiocarbamate, zinc dimethyldithiocarbamate, zinc diethyldithiocarbamate, zinc dibutyldithiocarbamate, zinc diamyldithiocarbamate, zinc dipropyldithiocarbamate , Complex salt of zinc pentamethylenedithiocarbamate and piperidine, zinc hexadecyl (or octadecyl) isopropyldithiocarbamate, zinc dibenzyldithiocarbamate, sodium diethyldithiocarbamate, piperidine pentamethylenedithiocarbamate, selenium dimethyldithiocarbamate, tellurium diethyldithiocarbamate, diamyl Dithiocarbamate such as cadmium It can be used carbamic acid compounds. As the aldehyde-amine system or aldehyde-ammonia system, for example, an aldehyde-amine system or an aldehyde-ammonia system compound such as an acetaldehyde-aniline reaction product, butyraldehyde-aniline condensate, hexamethylenetetramine, acetaldehyde-ammonia reaction product, or the like is used. be able to. As the imidazoline-based compound, for example, an imidazoline-based compound such as 2-mercaptoimidazoline can be used. As the xanthate type, for example, a xanthate type compound such as zinc dibutylxanthate can be used. These vulcanization accelerators may be used alone or in combination of two or more.

<Tire>
The rubber composition for a tread of the present invention uses the rubber component, the first silica, the second silica, and a material such as a composite material of starch and a plasticizer using a rubber kneading apparatus such as a Banbury mixer or an open roll. And can be prepared by mixing by kneading.

  The tread can be formed by extruding the rubber composition for a tread of the present invention in an unvulcanized state.

  Then, an unvulcanized green tire is produced by, for example, disposing a tire member including a tread formed from the rubber composition for a tread of the present invention at a predetermined position. Thereafter, the rubber composition constituting each member of the unvulcanized green tire is vulcanized to produce the tire of the present invention.

  When the tread of the present invention has a two-layer configuration of a base tread and a cap tread above the base tread, for example, a sheet of the tread rubber composition of the present invention is pasted into a predetermined shape. It can be produced by a method of combining them, or a method of inserting into two or more extruders and forming two layers at the head outlet of the extruder.

  FIG. 1 shows a schematic cross-sectional view of the upper left half of an example of the tire of the present invention. Here, the tire 1 includes a tread 2 that serves as a ground contact surface of the tire 1, a pair of sidewalls 3 that extend inward in the tire radial direction from both ends of the tread 2 to form the side surfaces of the tire 1, And a bead core 5 located at the inner end in the tire radial direction. A ply 6 is bridged between the bead cores 5 and 5, and a belt 7 is installed outside the ply 6 and inside the tread 2.

  For example, the ply 6 has an angle of, for example, 70 ° to 90 ° with respect to the tire equator CO (a virtual line obtained by rotating the center of the width of the outer peripheral surface of the tire 1 once in the circumferential direction of the outer peripheral surface of the tire 1). A plurality of cords can be formed from a rubber sheet embedded in the rubber composition. Further, the ply 6 is folded and locked around the bead core 5 from the tread 2 through the sidewall 3 to the outside in the tire axial direction.

  The belt 7 can be formed from, for example, a rubber sheet in which a plurality of cords that form an angle of, for example, 40 ° or less with respect to the tire equator CO is embedded in the rubber composition.

  Further, the tire 1 may be provided with a band (not shown) for suppressing the peeling of the belt 7 as necessary. Here, the band can be installed by, for example, a rubber sheet in which a plurality of cords are embedded in a rubber composition and spirally wound around the belt 7 substantially parallel to the tire equator CO.

  The tire 1 has a bead apex 8 extending outward in the tire radial direction from the bead core 5, and an inner liner 9 is installed inside the ply 6. Are covered with a side wall 3 and a clinch 4 extending inward in the tire radial direction from the side wall 3.

  In the above, a tire for a passenger car is illustrated as the tire 1 of the present invention, but the present invention is not limited to this, and is used for various vehicles such as passenger cars, trucks, buses, heavy vehicles and the like. Tire.

  The rubber composition for a tread according to the present invention includes a rubber component and a composite material of starch and a plasticizer with respect to 100 parts by mass of the rubber component, and having an average primary particle size of 20 nm or more. 10 parts by mass or more of 1 silica, 5 parts by mass or more of the second silica having an average primary particle diameter of less than 20 nm, and the total content of the first silica and the second silica is 100 parts by mass of the rubber component. In the tire having a tread formed using the rubber composition for a tread of the present invention, the rolling resistance, the steering stability of the vehicle, and the wet Excellent skid performance and wear resistance. Therefore, the rubber composition for tire treads of the present invention is preferably used for forming tire treads.

<Preparation of unvulcanized rubber composition>
According to the formulation shown in Table 1, components other than sulfur and a vulcanization accelerator were kneaded for 3 minutes using a Banbury mixer to obtain a kneaded product. Next, sulfur and a vulcanization accelerator were added to the obtained kneaded material, and kneaded using an open roll to obtain each of the unvulcanized rubber compositions of Examples 1 to 3 and Comparative Examples 1 and 2. Obtained.

  In addition, the numerical value of the column of the rubber | gum and additive of Table 1 represents the compounding quantity of an additive by a mass part when the compounding quantity of rubber | gum (SBR) is 100 mass parts.

(Note 1) SBR: E15 manufactured by Asahi Kasei Corporation
(Note 2) First silica: Ultrasil U360 manufactured by Degussa (average primary particle size: 28 nm)
(Note 3) Second silica: Ultrasil VN3 manufactured by Degussa (average primary particle size: 15 nm)
(Note 4) Silane coupling agent: Si75 manufactured by Degussa
(Note 5) Starch / Plasticizer / Composite: Matter-by 1128R manufactured by Novamont
(Note 6) Aromatic oil: Diana Process AH-24 manufactured by Idemitsu Kosan Co., Ltd.
(Note 7) Zinc oxide: Zinc oxide manufactured by Mitsui Mining & Smelting Co., Ltd. (Note 8) Stearic acid: Stearic acid “Kashiwa” manufactured by Nippon Oil & Fats Co., Ltd.
(Note 9) Anti-aging agent: Antigen 6C manufactured by Sumitomo Chemical Co., Ltd.
(Note 10) Wax: Sunnock N manufactured by Ouchi Shinsei Chemical Co., Ltd.
(Note 11) Sulfur: Powdered sulfur manufactured by Karuizawa Sulfur Co., Ltd. (Note 12) Vulcanization accelerator CZ: Noxeller CZ manufactured by Ouchi Shinsei Chemical Co., Ltd.
(Note 13) Vulcanization accelerator DPG: Noxeller D manufactured by Ouchi Shinsei Chemical Co., Ltd.
<Production of test tire>
A tread was produced by molding the unvulcanized rubber compositions of Examples 1 to 3 and Comparative Examples 1 and 2 produced as described above, and the produced tread was placed together with other tire members. An unvulcanized green tire was produced. This unvulcanized green tire was vulcanized in a vulcanizer to obtain a test tire of 195 / 65R15 size.

<Rolling resistance characteristics>
Rolling resistance when the test tire produced as described above using a rolling resistance tester was run under the conditions of rim: 15 × 6JJ, internal pressure: 230 kPa, load: 3.43 kN, speed: 80 km / h. Was measured. And rolling resistance index was computed by the following formula (1). The results are shown in the rolling resistance index column of Table 1. It shows that rolling resistance is so low that the numerical value of the column of rolling resistance index of Table 1 is large.

(Rolling resistance index) = 100 × (Measured value of rolling resistance of a test tire having a tread formed using the unvulcanized rubber composition of Comparative Example 1) / (Examples 1-3 and Comparative Examples 1- (2) Measured value of rolling resistance of each test tire having a tread formed using each unvulcanized rubber composition) (1)
<Wet skid performance>
Each of the test tires produced as described above was mounted on a test vehicle (domestic FF2000cc), and the vehicle was run on a test course on a wet asphalt road surface. Then, the test vehicle was run at an initial speed of 100 km / h, the braking distance from when the brake was applied to when it was stopped was measured, and the wet skid performance index was calculated by the following equation (2). The results are shown in the column of wet skid performance index in Table 1. The larger the value in the column of the wet skid performance index in Table 1, the better the wet skid performance.

(Wet skid performance index) = 100 × (Measured value of braking distance when a test tire having a tread formed using the unvulcanized rubber composition of Comparative Example 1) / (Examples 1 to 3) And the measured value of each braking distance when the test tire which has a tread formed using the unvulcanized rubber composition of each of Comparative Examples 1 and 2 is mounted) (2)
<Abrasion resistance>
Each of the test tires produced as described above is mounted on a test vehicle (domestic FF2000cc), runs on an asphalt road test course at 80 km / h, and the decrease in the groove depth of the tread pattern after running 30000 km is measured. did. Then, the wear resistance index was calculated by the following formula (3). The results are shown in the column of wear resistance index in Table 1. It shows that it is excellent in abrasion resistance, so that the numerical value of the column of abrasion resistance index of Table 1 is large.

(Abrasion resistance index) = 100 × (measured value of a decrease in groove depth when a test tire having a tread formed using the unvulcanized rubber composition of Comparative Example 1) / (implementation) (Measured value of each groove depth decrease value when a test tire having a tread formed using the unvulcanized rubber composition of each of Examples 1 to 3 and Comparative Examples 1 to 2) (3) )
<Steering stability>
The test tires produced as described above were mounted on all the wheels of a test vehicle (domestic FF2000cc), and the vehicle was run on a test course on an asphalt road surface. At that time, the steering stability index when the test driver having the tread formed using the unvulcanized rubber composition of Comparative Example 1 was mounted by the sensory evaluation of the steering stability was 6 As a point, the steering stability index of the vehicle was calculated with a maximum of 10 points. The results are shown in the column of the steering stability index in Table 1. The larger the numerical value in the column of the steering stability index in Table 1, the better the steering stability of the vehicle.

<Evaluation results>
As shown in Table 1, together with SBR which is a rubber component, the first material having a composite material of starch and a plasticizer of 1 to 30 parts by mass and an average primary particle size of 20 nm or more with respect to 100 parts by mass of SBR It contains 10 parts by mass or more of silica and 5 parts by mass or more of second silica having an average primary particle diameter of less than 20 nm, and the total content of the first silica and second silica is 100 parts by mass of the rubber component. When the tread is formed using the unvulcanized rubber compositions of Examples 1 to 3 set to 15 parts by mass or more and 150 parts by mass or less, the comparison does not include the composite material of starch and plasticizer. Compared to the case where a tread was formed using the unvulcanized rubber composition of Example 1 and the unvulcanized rubber composition of Comparative Example 2 containing no starch and plasticizer composite and the first silica. Rolling resistance, vehicle handling stability, wet It was confirmed that it is possible to make the Kid performance and abrasion resistance excellent comprehensively.

  It should be understood that the embodiments and examples disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  According to the present invention, a rubber composition for a tread capable of producing a tire excellent in rolling resistance, vehicle handling stability, wet skid performance and wear resistance, and formed using the rubber composition for a tread. A tread and a tire manufactured using the tread can be provided.

It is typical sectional drawing of the upper left half of an example of the tire of this invention.

Explanation of symbols

1 tire, 2 tread, 3 sidewall, 4 clinch, 5 bead core, 6
Ply, 7 belt, 8 bead apex, 9 inner liner.

Claims (3)

A rubber component comprising styrene-butadiene rubber , a composite material of starch and a plasticizer, a first silica having an average primary particle diameter of 20 nm or more, and a second silica having an average primary particle diameter of less than 20 nm. ,
The composite material is contained in an amount of 1 part by weight to 30 parts by weight with respect to 100 parts by weight of the rubber component,
The first silica is contained in an amount of 10 to 30 parts by mass with respect to 100 parts by mass of the rubber component,
The second silica is contained in an amount of 5 parts by mass or more based on 100 parts by mass of the rubber component,
The rubber composition for treads whose total content of said 1st silica and said 2nd silica is 15 to 150 mass parts with respect to 100 mass parts of said rubber components.   A tread formed using the rubber composition for a tread according to claim 1.   A tire manufactured using the tread according to claim 2.

Images