JP2015017216A - Tire rubber composition and pneumatic tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tire rubber composition in which, when a tire is made from the composition, grip performance, persistence and wear resistance are achieved at high levels.SOLUTION: A tire rubber composition comprises diene rubber, carbon black, and isocyanate having a (meth)acryloyl group, where the content of the carbon black is 5-180 pts.mass relative to the diene rubber 100 pts.mass, and the content of the isocyanate is 1-10 pts.mass relative to the diene rubber 100 pts.mass.

Description

  The present invention relates to a tire rubber composition and a pneumatic tire suitable for a competition tire.

  Tires are required to have mechanical properties such as wear resistance. On the other hand, carbon black is generally blended as a reinforcing agent in a rubber composition for tires.

  For example, claim 1 of Patent Document 1 discloses a rubber composition for tire treads containing a diene rubber and carbon black. Patent Document 1 describes that the tire wear resistance is improved by adopting the configuration of claim 1.

JP 2012-207185 A

  On the other hand, in recent years, in order to improve safety and the like, it has been demanded that both grip performance, sustainability and wear resistance are compatible at a high level. In particular, competition tires are required to satisfy the above-described characteristics at an extremely high level at a high temperature (for example, 100 ° C.).

Under such circumstances, the present inventor examined a rubber composition containing a diene rubber and carbon black based on Patent Document 1, and found that at least one of grip performance, durability, and wear resistance was used. It became clear that the characteristics do not meet the level required recently. That is, it has become clear that the above-described characteristics are not compatible at the level required recently.
In view of the above circumstances, an object of the present invention is to provide a rubber composition for a tire that is compatible with grip performance, durability, and wear resistance at a high level when made into a tire.

As a result of intensive studies on the above-mentioned problems, the present inventors have blended an isocyanate having a (meth) acryloyl group, so that a tire having both high grip performance, durability and wear resistance when made into a tire is achieved. The present inventors have found that a rubber composition can be obtained, and have reached the present invention.
That is, the present inventors have found that the above problem can be solved by the following configuration.

(1) containing a diene rubber, carbon black, and an isocyanate having a (meth) acryloyl group,
The content of the carbon black is 5 to 180 parts by mass with respect to 100 parts by mass of the diene rubber, and the content of the isocyanate is 1 to 10 parts by mass with respect to 100 parts by mass of the diene rubber. A tire rubber composition.
(2) The nitrogen adsorption specific surface area of the carbon black is 90 to 400 m ² / g,
The tire rubber composition according to (1), wherein the carbon black content is 40 to 180 parts by mass with respect to 100 parts by mass of the diene rubber.
(3) The isocyanate is a blocked isocyanate,
The tire rubber composition according to (1) or (2), wherein the blocked isocyanate has a 90% deblocking temperature of 110 to 170 ° C.
(4) The above (1) to (3), wherein the diene rubber contains 50% by mass or more of an aromatic vinyl-conjugated diene copolymer rubber modified with a functional group capable of reacting with an isocyanate group of the isocyanate. The tire rubber composition according to any one of the above.
(5) The rubber composition for tires according to any one of the above (1) to (4), which is used for competition tires.
(6) A pneumatic tire manufactured using the tire rubber composition according to any one of (1) to (5).
(7) The pneumatic tire according to (6), which is a competition tire.

  As described below, according to the present invention, it is possible to provide a rubber composition for a tire that is compatible with grip performance, durability, and wear resistance at a high level when made into a tire.

It is a partial section schematic diagram of the tire showing an example of the embodiment of the pneumatic tire of the present invention.

  Below, the rubber composition for tires of this invention and the pneumatic tire manufactured using the rubber composition for tires of this invention are demonstrated.

[Rubber composition for tire]
The rubber composition for tires of the present invention (hereinafter also referred to as the composition of the present invention) contains a diene rubber, carbon black, and an isocyanate having a (meth) acryloyl group.
Here, the content of the carbon black is 5 to 180 parts by mass with respect to 100 parts by mass of the diene rubber, and the content of the isocyanate is 1 to 100 parts by mass of the diene rubber. 10 parts by mass.
Since the composition of the present invention has such a structure, it is considered that the grip performance, durability, and wear resistance are compatible at a high level when the tire is formed.

The reason is not clear, but it is presumed that it is as follows.
In general, increasing the carbon black or oil to increase the grip performance decreases the mechanical properties, and conversely, increasing the sulfur to increase the mechanical properties tends to decrease the grip performance. That is, it can be said that the grip performance and the mechanical properties are in a trade-off relationship.
Here, as described above, since the composition of the present invention contains an isocyanate having a (meth) acryloyl group (hereinafter also referred to as a specific isocyanate), when the composition of the present invention is vulcanized, the isocyanate of the specific isocyanate The group and the (meth) acryloyl group appropriately crosslink the diene rubber to form a three-dimensional network structure excellent in flexibility and toughness. As a result, it is considered that the tire obtained from the composition of the present invention is compatible with grip performance, durability, and wear resistance at a high level. As shown in Examples and Comparative Examples which will be described later, this is because the tire (Examples 1 to 5) containing the specific isocyanate is more suitable for the tire than the case containing the specific isocyanate (Comparative Examples 1 to 5). It is also speculated that the grip performance, durability and wear resistance are compatible at a high level.

  Hereinafter, each component contained in the composition of this invention is explained in full detail.

<Diene rubber>
The diene rubber contained in the composition of the present invention is not particularly limited, and specific examples thereof include natural rubber (NR), isoprene rubber (IR), butadiene rubber (BR), aromatic vinyl-conjugated diene copolymer. Examples include coal rubber, acrylonitrile-butadiene copolymer rubber (NBR), butyl rubber (IIR), halogenated butyl rubber (Br-IIR, Cl-IIR), and chloroprene rubber (CR). The diene rubber may be a single diene rubber or a combination of two or more diene rubbers.

  The diene rubber is preferably a modified rubber. Among these, a modified rubber modified with a functional group (preferably a hydroxy group) capable of reacting with an isocyanate group possessed by a specific isocyanate described later (in the case where the specific isocyanate is a blocked isocyanate, an isocyanate group generated from the blocked isocyanate group). It is preferable that the rubber is modified rubber having a terminal modified with a hydroxy group.

As the diene rubber, it is preferable to use an aromatic vinyl-conjugated diene copolymer rubber (particularly, one having a terminal modified with a hydroxy group) because the rigidity of the resulting tire is excellent.
Examples of the aromatic vinyl-conjugated diene copolymer rubber include styrene butadiene rubber (SBR) and styrene isoprene copolymer rubber. Among these, styrene butadiene rubber (SBR) is preferable because the rigidity of the obtained tire is excellent.

The aromatic vinyl content (for example, styrene content) of the aromatic vinyl-conjugated diene copolymer is preferably 20 to 45 mass%, more preferably 23 to 42 mass%.
Further, the vinyl bond content in the conjugated diene of the aromatic vinyl-conjugated diene copolymer is preferably 10 to 50%, and more preferably 25 to 48%. Here, the amount of vinyl bonds refers to the ratio of 1,2-vinyl bonds among cis-1,4-bonds, trans-1,4-bonds and 1,2-vinyl bonds, which are conjugated dienes. Say.

The said aromatic vinyl-conjugated diene copolymer is not specifically limited about the manufacturing method, It can manufacture by a conventionally well-known method.
Moreover, the aromatic vinyl and conjugated diene as a monomer used when manufacturing the said aromatic vinyl-conjugated diene copolymer are not specifically limited.
Here, examples of the conjugated diene monomer include 1,3-butadiene, isoprene (2-methyl-1,3-butadiene), 2,3-dimethyl-1,3-butadiene, and 2-chloro-1. , 3-butadiene, 1,3-pentadiene and the like.
On the other hand, examples of the aromatic vinyl monomer include styrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, α-methylstyrene, 2,4-dimethylstyrene, 2,4-diisopropylstyrene, Examples include 4-tert-butylstyrene, divinylbenzene, tert-butoxystyrene, vinylbenzyldimethylamine, (4-vinylbenzyl) dimethylaminoethyl ether, N, N-dimethylaminoethylstyrene, and vinylpyridine.

  The content in the case of using the aromatic vinyl-conjugated diene copolymer is preferably 50% by mass or more, more preferably 70% by mass or more of the diene rubber, because the rigidity of the obtained tire is excellent. Is more preferable, and it is still more preferable that it is 90 mass% or more.

  The diene rubber is an aromatic vinyl-conjugated diene copolymer modified with a functional group capable of reacting with an isocyanate group possessed by a specific isocyanate described below (or an isocyanate group generated from a blocked isocyanate group when the specific isocyanate is a blocked isocyanate). It is preferable to contain 50% by mass or more of polymer rubber.

  The weight average molecular weight of the diene rubber is preferably 100,000 to 1,500,000 from the viewpoint of the toughness of the obtained tire and the handling of the composition of the present invention, and 600,000 to 1,300,000. More preferably, it is 000. The weight average molecular weight (Mw) of the diene rubber is measured by standard polystyrene conversion by gel permeation chromatography (GPC) using tetrahydrofuran as a solvent.

<Carbon black>
The carbon black contained in the composition of the present invention is not particularly limited. For example, SAF-HS, SAF, ISAF-HS, ISAF, ISAF-LS, IISAF-HS, HAF-HS, HAF, HAF-LS, Various grades such as FEF can be used.
The nitrogen adsorption specific surface area (N ₂ SA) of the carbon black is preferably 90 to 400 m ² / g, and more preferably 120 to 300 m ² / g, because the resulting tire has excellent rigidity.
Here, the nitrogen adsorption specific surface area (N ₂ SA) is the nitrogen adsorption amount on the carbon black surface according to JIS K6217-2: 2001 “Part 2: Determination of specific surface area—nitrogen adsorption method—single point method”. It is a measured value.

The carbon black content is 5 to 180 parts by mass with respect to 100 parts by mass of the diene rubber. Especially, it is preferable that it is 40-180 mass parts, and it is more preferable that it is 50-150 mass parts from a viewpoint of the balance of the rigidity of a tire and low rolling resistance obtained.
When the content of the carbon black is less than 5 parts by mass with respect to 100 parts by mass of the diene rubber, grip performance and wear resistance are insufficient. Moreover, when content of the said carbon black exceeds 180 mass parts with respect to 100 mass parts of said diene rubbers, abrasion resistance and sustainability will deteriorate.

<Specific isocyanate>
The composition of the present invention contains an isocyanate having a (meth) acryloyl group (specific isocyanate). The specific isocyanate is a compound having a (meth) acryloyl group and an isocyanate group ((—N═C═O)).
Here, the (meth) acryloyl group represents an acryloyl group (CH ₂ ═CH—CO—) or a methacryloyl group (CH ₂ ═CCH ₃ —CO—).
The isocyanate group may be a blocked isocyanate group protected with a blocking agent.

  The specific isocyanate may be a polymer (polymer). When the specific isocyanate is a linear polymer, it preferably has a (meth) acryloyl group at one end.

  Specific examples of the specific isocyanate include 2-isocyanate ethyl acrylate, 2-isocyanate ethyl methacrylate, 3-isocyanate propyl acrylate, 3-isocyanate propyl methacrylate, 2-isocyanate 1-methyl ethyl acrylate, 2-isocyanate 1-methyl ethyl methacrylate, 3-acryloyloxyphenyl isocyanate, 3-methacryloyloxyphenyl isocyanate, 3-isocyanate 2-methylbutyl acrylate, 3-isocyanate 2-methylbutyl methacrylate, 4-acryloyloxyphenyl isocyanate, 4-methacryloyloxyphenyl isocyanate, 3-acryloyloxy Phenyl isocyanate, 3-methacryloyloxyphenyl isocyanate , 2-acryloyloxyphenyl isocyanate, 2-methacryloyloxyphenyl isocyanate, 3,5-bis (methacryloyloxyethyl) phenyl isocyanate, 2,4-bis (acryloyloxy) phenyl isocyanate, 1,1-bis (acryloyloxy) And methyl) ethyl isocyanate, 1,1-bis (methacryloyloxymethyl) ethyl isocyanate, acryloyl isocyanate, methacryloyl isocyanate, and the like.

  As a suitable aspect of specific isocyanate, the compound represented by following formula (1) is mentioned, for example.

In the above formula (1), R ¹¹ represents a hydrogen atom or a methyl group. Of these, a methyl group is preferable.

In the above formula (1), L ¹¹ represents a single bond or a divalent organic group. Although it does not restrict | limit especially as a bivalent organic group, For example, a bivalent aliphatic hydrocarbon group (for example, alkylene group, Preferably it is C1-C8), A bivalent aromatic hydrocarbon group (for example, arylene group) Preferably having 6 to 12 carbon atoms), —O—, —S—, —SO ₂ —, —N (R) — (R: alkyl group), —CO—, —NH—, —COO—, —CONH. -Or a combination thereof (for example, an alkyleneoxy group, an alkyleneoxycarbonyl group, an alkylenecarbonyloxy group, and the like). Among these, an alkylene group, —O—, or a combination thereof is preferable.

(Specific block isocyanate)
The specific isocyanate is preferably a blocked isocyanate because the grip performance and wear resistance of the resulting tire are more excellent. That is, the specific isocyanate is preferably a blocked isocyanate having a (meth) acryloyl group (hereinafter also referred to as a specific blocked isocyanate).
The specific blocked isocyanate is a compound having a (meth) acryloyl group and a blocked isocyanate group in which the isocyanate group is protected with a blocking agent. When the specific isocyanate is a specific blocked isocyanate, the blocking agent is dissociated from the blocked isocyanate group during vulcanization, and an isocyanate group is generated.

The blocking agent is not particularly limited, but is preferably an active hydrogen group-containing compound, such as alcohols, phenols, oximes, triazoles, caprolactams, thiols, amines, imines, carbazoles, Examples include amides, imides, ureas, acetoacetic acid alkyl esters, malonic acid alkyl esters, pyrazoles, imidazoles, and the like, among which pyrazoles are preferable.
Specific examples of the blocking agent include thiols, methanethiol, ethanethiol, benzenethiol, phenols, phenol, o-nitrophenol, m-nitrophenol, p-nitrophenol, cresol, 1- Naphthol, 2-naphthol, oximes as acetone oxime, methyl ethyl ketoxime, methyl isobutyl ketoxime, cyclohexanone oxime, amines as dibutylamine, diphenylamine, aniline, imines as ethyleneimine, propyleneimine, carbazoles as unsubstituted As carbazole, 1,3,6,8-tetranitrocarbazole, 3,6-dibromocarbazole, amides, acetanilide, acetic acid amide, ε-caprolactam, γ-butyrolol Kutam, imides, succinimide, N-hydroxysuccinimide, maleic imide, urea as urea, ethylene urea, thiourea, acetoacetic acid alkyl esters, acetoacetic acid ethyl ester, malonic acid alkyl esters Diethyl malonate, pyrazoles, unsubstituted pyrazole, 3,5-dimethylpyrazole, 3-acetylaminopyrazole, pyrazole-3,5-dicarboxylic acid diethyl ester, imidazoles, unsubstituted imidazole, 2-methylimidazole 1,2-ethylimidazole, 2-phenylimidazole, and triazoles include 1,2,3-triazole, 1,2,4-triazole, benzotriazole, and the like.

  As a suitable aspect of specific block isocyanate, the compound represented by following formula (2) is mentioned, for example.

In the above formula (2), the definition and preferred embodiment of R ²¹ are the same as R ¹¹ described above.
In the above formula (2), the definition, specific examples and preferred embodiments of L ²¹ are the same as L ¹¹ described above.

  In the above formula (2), B represents a group obtained by removing the active hydrogen group from the blocking agent having an active hydrogen group (residue obtained by reacting the blocking agent having an active hydrogen group with an isocyanate group). Specific examples and preferred embodiments of the blocking agent are as described above.

The 90% deblocking temperature of the specific blocked isocyanate is not particularly limited, but is preferably 110 to 170 ° C, and more preferably 115 to 140 ° C.
Here, the 90% deblocking temperature is a temperature at which 90% of the blocked isocyanate groups possessed by the specific blocked isocyanate is dissociated to become isocyanate groups. 90% deblocking temperature is calculated | required by analyzing content of the isocyanate group of the heated specific block isocyanate by NMR method or MS method.

  The production method of the specific blocked isocyanate is not particularly limited, but as a preferred embodiment, for example, a method of reacting the isocyanate group of the above-mentioned specific isocyanate (a compound having a (meth) acryloyl group and an isocyanate group) with a blocking agent. Can be mentioned. Specific examples and preferred embodiments of the blocking agent are as described above.

In the composition of the present invention, the content of the specific isocyanate is 1 to 10 parts by mass with respect to 100 parts by mass of the diene rubber. Especially, it is preferable that it is 2.0 mass parts or more from the reason which the sustainability of the tire obtained is more excellent.
When the content of the specific isocyanate is less than 1 part by mass with respect to 100 parts by mass of the diene rubber, the grip performance, durability and wear resistance of the obtained tire are insufficient. Moreover, when content of specific isocyanate exceeds 10 mass parts with respect to 100 mass parts of said diene rubbers, grip property will deteriorate.

<Optional component>
If necessary, the composition of the present invention may further contain an additive within a range not impairing its effects and purposes.
Examples of the additive include fillers other than carbon black (for example, silica), silane coupling agents (for example, Si69 manufactured by Evonik Degussa, Si363 manufactured by Evonik Degussa), zinc oxide (zinc white), stearic acid, Various additives commonly used in rubber compositions such as anti-aging agents, processing aids, oils, liquid polymers, terpene resins, thermosetting resins, vulcanizing agents (eg, sulfur), vulcanization accelerators, etc. Can be mentioned.

The composition of the present invention preferably contains a terpene resin because the grip performance of the resulting tire is more excellent. The terpene resin is preferably an aromatic modified terpene resin (particularly having a softening point of 60 to 180 ° C.).
In the composition of the present invention, the content of the terpene resin is not particularly limited, but is preferably 1 to 50 parts by mass, and 10 to 40 parts by mass with respect to 100 parts by mass of the diene rubber. More preferred.

<Method for producing rubber composition for tire>
The production method of the composition of the present invention is not particularly limited, and specific examples thereof include, for example, kneading the above-described components using a known method and apparatus (for example, a Banbury mixer, a kneader, a roll, etc.). The method etc. are mentioned. When the composition of the present invention contains sulfur or a vulcanization accelerator, components other than sulfur and the vulcanization accelerator are first mixed at a high temperature (preferably 140 to 160 ° C.) and cooled, and then sulfur or It is preferable to mix a vulcanization accelerator.
The composition of the present invention can be vulcanized or crosslinked under conventionally known vulcanization or crosslinking conditions.

[Pneumatic tire]
The pneumatic tire of the present invention is a pneumatic tire manufactured using the composition of the present invention described above. Especially, it is preferable that it is a pneumatic tire which used the composition of this invention for the tire tread.
FIG. 1 shows a schematic partial sectional view of a tire representing an example of an embodiment of the pneumatic tire of the present invention, but the pneumatic tire of the present invention is not limited to the embodiment shown in FIG.

In FIG. 1, reference numeral 1 represents a bead portion, reference numeral 2 represents a sidewall portion, and reference numeral 3 represents a tire tread portion.
Further, a carcass layer 4 in which fiber cords are embedded is mounted between the pair of left and right bead portions 1, and the end of the carcass layer 4 extends from the inside of the tire to the outside around the bead core 5 and the bead filler 6. Wrapped and rolled up.
In the tire tread 3, a belt layer 7 is disposed over the circumference of the tire on the outside of the carcass layer 4.
Moreover, in the bead part 1, the rim cushion 8 is arrange | positioned in the part which touches a rim | limb.

  The pneumatic tire of the present invention can be manufactured, for example, according to a conventionally known method. Moreover, as gas with which a tire is filled, inert gas, such as nitrogen, argon, helium other than the air which adjusted normal or oxygen partial pressure, can be used.

  The pneumatic tire of the present invention is suitable for competition tires because it is compatible with grip performance, sustainability, and wear resistance at high levels even at high temperatures (for example, 100 ° C.).

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these.

<Examples 1-5, Comparative Examples 1-5>
The components shown in Table 1 below were blended in the proportions (parts by mass) shown in Table 1 below.
Specifically, first, among the components shown in Table 1 below, the components excluding sulfur and the vulcanization accelerator were mixed for 5 minutes using a 1.7 liter closed Banbury mixer, and reached 150 ± 5 ° C. Was released and cooled to room temperature to obtain a masterbatch. Furthermore, using the Banbury mixer, sulfur and a vulcanization accelerator were mixed into the obtained master batch to obtain a tire rubber composition.
In Table 1, regarding the amount of SBR, the upper value is the amount of SBR (oil-extended product) (unit: parts by mass), and the lower value is the net amount of SBR contained in SBR (unit: parts by mass) It is.

<Preparation of vulcanized rubber sheet for evaluation>
The prepared tire rubber composition (unvulcanized) was press-vulcanized at 160 ° C. for 20 minutes in a mold (15 cm × 15 cm × 0.2 cm) to produce a vulcanized rubber sheet.

<Tan δ (100 ° C.)>
About the vulcanized rubber sheet produced as described above, in accordance with JIS K6394: 2007, using a viscoelastic spectrometer (manufactured by Iwamoto Seisakusho Co., Ltd.), the tensile deformation strain rate is 10% ± 2%, the frequency is 20 Hz, and the temperature is 100 ° C. Under the conditions, tan δ (100 ° C.) was measured.
The results are shown in Table 1. The results were expressed as an index with tan δ (100 ° C.) of Comparative Example 1 as 100. The larger the index, the larger the tan δ (100 ° C.), and the better the grip performance when made into a tire.

<300% modulus (100 ° C)>
About the vulcanized rubber sheet produced as described above, a JIS No. 3 dumbbell-shaped test piece (thickness 2 mm) is punched in accordance with JIS K6251: 2010, and a 300% modulus (300% at a temperature of 100 ° C. and a pulling speed of 500 mm / min. % Stress at the time of deformation).
The results are shown in Table 1. The results were expressed as an index with the 300% modulus of Comparative Example 1 as 100. The larger the index, the larger the 300% modulus, and the better the durability when made into a tire.

<Breaking strength (100 ° C)>
For the vulcanized rubber sheet produced as described above, in accordance with JIS K6251: 2010, a JIS No. 3 dumbbell-shaped test piece (thickness 2 mm) is punched, and the breaking strength (at the time of breaking at a temperature of 100 ° C. and a pulling speed of 500 mm / min. Stress).
The results are shown in Table 1. The results were expressed as an index with the breaking strength of Comparative Example 1 as 100. The greater the index, the greater the breaking strength and the better the wear resistance when made into a tire.

Details of each component shown in Table 1 are as follows.
SBR: E581 (styrene butadiene rubber having a hydroxyl group at the end, oil-extended product (including 37.5 parts by mass of oil-extended oil with respect to 100 parts by mass of SBR. The net SBR in SBR is 72.7% by mass), Styrene content: 37% by mass, vinyl bond content: 42%, weight average molecular weight: 1,260,000, manufactured by Asahi Kasei Corporation)
Carbon black 1: Dia black A (N ₂ SA = 142 m ² / g, manufactured by Mitsubishi Chemical Corporation)
Carbon black 2: Seast KHA (N ₂ SA = 77 m ² / g, manufactured by Tokai Carbon Co., Ltd.)
Resin: YS resin TO-125 (aromatic modified terpene resin, softening point: 125 ° C., manufactured by Yasuhara Chemical Co., Ltd.)
・ Oil: Extract No. 4 S (made by Showa Shell Sekiyu KK)
・ Zinc flower: 3 types of zinc oxide (manufactured by Shodo Chemical Industries)
・ Stearic acid: Bead stearic acid YR (manufactured by NOF Corporation)
・ Sulfur: Fine sulfur with Jinhua stamp oil (manufactured by Tsurumi Chemical Co., Ltd.)
・ Vulcanization accelerator: Noxeller CZ-G (manufactured by Ouchi Shinsei Chemical Co., Ltd.)
・ Isocyanate 1: Karenz MOI (2-isocyanate ethyl methacrylate, Showa Denko)
Isocyanate 2: Karenz MOI-BP (90% deblocking temperature: 120 ° C.) (compound represented by the above formula (2). Here, R ²¹ : —CH ₃ , L ²¹ : —O—CH ₂ —CH ₂₋ , B: Structure represented by the following formula (B1).) (Manufactured by Showa Denko KK)

  In the above formula (B1), * represents a bonding position.

As can be seen from Table 1, the grip performance, durability and wear resistance of the Examples 1 to 5 containing the specific isocyanate when compared to the Comparative Examples 1 to 5 not containing the specific isocyanate when the tire is made. It was compatible at a high level. Among them, Examples 3 and 4 in which the specific isocyanate was a blocked isocyanate were more excellent in grip performance and wear resistance.
From the comparison between Examples 1 and 2 and the comparison between Examples 3 and 4, the content of the specific isocyanate is 2.0 parts by mass or more with respect to 100 parts by mass of the diene rubber. However, it showed better durability.
Further, in comparison with Examples 1 and 5, Example 5 containing an aromatic-modified terpene resin showed more excellent grip performance.

1 Bead part 2 Side wall part 3 Tire tread part 4 Carcass layer 5 Bead core 6 Bead filler 7 Belt layer 8 Rim cushion

Claims (7)

Containing a diene rubber, carbon black, and an isocyanate having a (meth) acryloyl group,
The carbon black content is 5 to 180 parts by mass with respect to 100 parts by mass of the diene rubber, and the isocyanate content is 1 to 10 parts by mass with respect to 100 parts by mass of the diene rubber. A tire rubber composition. The carbon black has a nitrogen adsorption specific surface area of 90 to 400 m ² / g,
The tire rubber composition according to claim 1, wherein a content of the carbon black is 40 to 180 parts by mass with respect to 100 parts by mass of the diene rubber. The isocyanate is a blocked isocyanate;
The rubber composition for tires according to claim 1 or 2 whose 90% deblocking temperature of said blocked isocyanate is 110-170 ° C.   The diene rubber according to any one of claims 1 to 3, wherein the diene rubber contains 50% by mass or more of an aromatic vinyl-conjugated diene copolymer rubber modified with a functional group capable of reacting with an isocyanate group of the isocyanate. The rubber composition for tires as described.   The rubber composition for tires of any one of Claims 1-4 used for a competition tire.   The pneumatic tire manufactured using the rubber composition for tires of any one of Claims 1-5.   The pneumatic tire according to claim 6 which is a competition tire.