JP3457479B2 - Rubber composition and pneumatic tire using the same - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a rubber composition,
More specifically, it relates to a rubber composition having extremely low hysteresis loss and a high level of wet skid. The present invention also relates to a pneumatic tire using this rubber composition for a tire tread, and more specifically to a pneumatic tire having significantly improved low rolling resistance performance (fuel economy) and excellent wet skid performance.

[0002]

2. Description of the Related Art In recent years, along with the demand for safety and low fuel consumption for automobiles, good wet skid properties and low hysteresis loss properties (and low tire rolling resistance performance, low tire resistance performance) have been achieved in rubber materials for tires. It is strongly demanded that fuel efficiency is satisfied at the same time. It is generally known that these two characteristics have an antinomy relationship. That is, when the low hysteresis loss property (low rolling resistance performance) is set, the wet skid property is deteriorated, and when the wet skid property is improved, the low hysteresis loss property is deteriorated.

In the prior art, in order to solve the above problems,
Improvements in rubber compositions for tires have been made from both sides of polymer type and carbon black type.

Focusing on the improvement of the rubber composition by the carbon black system, many techniques are known as exemplified below. In an example of increasing the particle size of carbon black, it is known that the rubber composition has a low hysteresis loss property, but the wet skid property is deteriorated. Only the surface chemical properties of carbon black and the effect of the rubber composition for tires (and by extension the pneumatic tire using the same) will be described, but in JP-A-64-20246, the concentration and pH of all acidic groups are mainly described. A rubber composition having improved exothermic properties and reinforcing properties at high temperatures using carbon black whose value is specified; in JP-A-2-105836, carbon black mainly specified in the number of oxygen-containing functional groups is used. And a rubber composition having excellent wet skid characteristics, rolling friction resistance, and reinforcement at high temperature;
No. 837 discloses a rubber composition which mainly uses carbon black whose oxygen-containing functional group concentration is specified and which is excellent in rolling friction resistance and reinforcement at high temperature;
In Japanese Patent Publication No. 144, rolling resistance and abrasion resistance are mainly used by using carbon black whose relationship with the amount of functional groups that undergo acetylation reaction with acetic anhydride and the amount of functional groups that react with hydroxylamine to form oximes is specified. In JP-A-4-189845, carbon black having a specified concentration of -OH functional group which reacts with acetylation with acetic anhydride is mainly used, and it has excellent rolling friction resistance and reinforcement at high temperature. Rubber composition;
No. 25472, a rubber composition using mainly oxidized carbon black and having excellent low rolling resistance and traction characteristics; JP-A No. 6-107863 discloses a quinone group concentration in NaOH and a quinone group concentration in NaOH. A rubber composition and the like having excellent reinforcing properties are disclosed by using carbon black whose total acidity determined by the Japanese method is specified.

[0005]

However, in these prior arts, the rubber composition containing carbon black having the characteristic surface chemical properties as described above, a modified rubber in some cases, and various compounding agents in some cases is used in the present invention. Although many aim to achieve different purposes, some attempts have been made to achieve the same purpose as the present invention, but they cannot be said to be sufficient. That is, the low hysteresis loss property (low rolling resistance performance) is remarkably improved,
At the same time, there is no known rubber composition or pneumatic tire that satisfies a high level of wet skid properties.

Therefore, an object of the present invention is to provide a rubber composition excellent in low hysteresis loss property and wet skid property. Another object of the present invention is to provide a pneumatic tire having improved low rolling resistance performance and wet skid performance at the same time.

[0007]

[Means for Solving the Problems] In order to solve the above-mentioned problems, the present inventors have made diligent studies by paying attention to the chemical structure, chemical properties and physical properties of carbon black surface and various rubber additives. As a result, they have found that the above-mentioned required properties can be satisfied at the same time by the following means using a specific carbon black and a specific additive, and have completed the present invention. (1) The rubber composition of the present invention has the characteristics represented by the following general formula (I) with respect to 100 parts by weight of at least one rubber selected from the group consisting of conjugated diene-based synthetic rubber and natural rubber. A silane coupling agent selected from the group consisting of the compounds represented by the following general formulas (II) and (III), and the following general formulas (IV) and (V). And a hydrazide compound selected from the group consisting of compounds represented by (VI) and at least one thiadiazole compound selected from the group consisting of compounds represented by the following general formula (VII) in an amount of 0.05 to 5 And 0.0 part by weight.

The general formula (I) [> C = O functional group concentration] / N ₂ SA ≧ 4.0 × 10 ⁻⁴ (wherein, [> C═O functional group concentration] is the oxime by reacting with hydroxylamine. Functional group concentration (meq /
g), and N ₂ SA is a nitrogen adsorption specific surface area (m ² / m
g) is represented. ]

[0009]

[Chemical 8]

(Wherein X ¹ represents a nitroso group, a mercapto group, an amino group, an epoxy group, a vinyl group, a chlorine atom or an imide group, and Y ¹ represents an alkoxy group having 1 to 4 carbon atoms or a chlorine atom. , Y ² represents an alkyl group having 1 to 4 carbon atoms, a represents an integer of 1 to 3, b represents an integer of 0 to 2, a + b = 3, and n and m each represent 1 to 6 Represents an integer.)

[0011]

[Chemical 9]

(Where X ² is represented by the following equation,

[0013]

[Chemical 10]

(Y ¹ represents an alkoxy group having 1 to 4 carbon atoms or a chlorine atom, Y ² represents an alkyl group having 1 to 4 carbon atoms, a is an integer of 1 to 3, and b is 0 to 2). Respectively, a + b = 3, and n and m each represent an integer of 1 to 6.)

[0015]

[Chemical 11]

[0016]

[Chemical 12]

[0017]

[Chemical 13]

(In the formula, A represents an aromatic ring, a saturated or unsaturated hydantoin ring, or a linear saturated or unsaturated alkyl group having 1 to 18 carbon atoms, n is 0 or 1, and B is an aromatic ring. , Z represents a hydroxyl group or an amino group, and L represents a pyridyl group or a hydrazino group.)

[0019]

[Chemical 14]

(In the formula, R ¹ represents a mercapto group, and R ²
Represents a mercapto group, an amino group or a trifluoromethyl group. (2) The rubber composition of the present invention is characterized in that, in the item (1), the conjugated diene-based synthetic rubber is a polybutadiene rubber and / or a styrene-butadiene rubber. (3) In the rubber composition of the present invention, in the above item (1), at least one selected from the group consisting of furnace black and channel-type carbon black is oxidized by an oxidizing means. It is characterized by being carbon black obtained by applying. (4) In the rubber composition of the present invention, in the above item (1), at least one selected from the group consisting of furnace black and channel type carbon black is oxidized by an oxidizing means. Further, it is characterized in that it is a carbon black obtained by heat treatment at a temperature of 100 to 900 ° C. (5) The pneumatic tire of the present invention is a pneumatic tire including a tread portion, a sidewall portion, and a bead portion, wherein the tread portion is at least one selected from the group consisting of conjugated diene synthetic rubber and natural rubber. Rubber 100
Selected from the group consisting of 30 to 120 parts by weight of carbon black having the characteristics represented by the general formula (I) and compounds represented by the general formulas (II) and (III) per part by weight. A silane coupling agent having the above general formula (IV)
, A hydrazide compound selected from the group consisting of compounds represented by the formulas (V) and (VI) and at least one of thiadiazole compounds selected from the group consisting of the compounds represented by the general formula (VII). .05 to 5.0 parts by weight,
It is characterized in that a blended rubber composition is used. (6) The pneumatic tire of the present invention is characterized in that in the above (5), the conjugated diene-based synthetic rubber is a polybutadiene rubber and / or a styrene-butadiene rubber. (7) In the pneumatic tire of the present invention, in the above (5), at least one selected from the group consisting of furnace black and channel-type carbon black is oxidized by an oxidizing means. It is characterized by being carbon black obtained by applying. (8) In the pneumatic tire of the present invention, in the above (5), at least one selected from the group consisting of furnace black and channel type carbon black is subjected to oxidation treatment by an oxidizing means, Further, it is characterized in that it is a carbon black obtained by performing a heat treatment at a temperature of 100 to 900 ° C.

It is essential that the carbon black compounded in the rubber composition of the present invention satisfies one characteristic. The characteristic is that [> C = O functional group concentration] / N ₂ SA is 4.
It means 0 × 10 ⁻⁴ or more (hereinafter, referred to as X characteristic). There are various functional groups on the carbon black surface,
As described above, in the prior art, carbon black is specified by using various parameters based on these functional groups. In the present invention, the carbon black specified by the X characteristic relating to the> C═O functional group concentration is used. X characteristic is> C
═O represents the required amount of functional group concentration. The rubber composition exhibits the effects of low hysteresis loss and wet skid for the first time by using the carbon black satisfying the X characteristics and the specific additive described later. It is difficult to achieve compatibility of effects even if either carbon black or the specific additive is lacking. Carbon black having an X characteristic of less than 4.0 × 10 ⁻⁴ is not effective enough.

The carbon black used in the present invention may be a commercially available product, a commercially available product treated or a newly manufactured product as long as it has the above-mentioned X characteristics. Although not particularly limited, for example, (1) gas furnace black, (2) channel type carbon black, (3) furnace black (including oil furnace black and gas furnace black) or channel type carbon black is HN.
_{O 3, H 2 O 2,} O 3, that has been subjected to oxidation treatment by oxidation means such as bichromate, (4) 100 gas furnace black or channel type carbon black
Heat treated at a temperature of 900 ° C., (5) above (3)
The carbon black that has been subjected to the oxidation treatment of
The thing which heat-processed at the temperature of -900 degreeC etc. can be mentioned. Among them, the carbon blacks (3) and (5) are preferable from the viewpoint of the effect.

The amount of carbon black used in the rubber composition of the present invention is 30 to 1 with respect to 100 parts by weight of rubber.
20 parts by weight, preferably 35 to 100 parts by weight, 3
If it is less than 0 parts by weight, a rubber composition having a sufficient elastic modulus cannot be obtained and the reinforcing property cannot be secured, and if it exceeds 120 parts by weight, sufficient carbon dispersion cannot be obtained and the reinforcing property is deteriorated, which is not preferable.

The rubber used in the rubber composition of the present invention is at least one rubber selected from the group consisting of conjugated diene synthetic rubber and natural rubber.

The conjugated diene-based synthetic rubber includes (1) a rubber obtained by polymerizing a conjugated diene monomer, (2) a rubber obtained by copolymerizing a conjugated diene monomer and a vinyl aromatic hydrocarbon monomer, and the like. . These synthetic rubbers may be used alone or in combination of two or more. Further, these synthetic rubbers are preferably used as a blend with natural rubber. In this case, the weight ratio of synthetic rubber / natural rubber is about 90/10 to 30/70.

Examples of the conjugated diene monomer include 1,
3-butadiene, isoprene, 2,3-dimethyl-1,
3-Butadiene, 1,3-pentadiene, 1,3-hexadiene and the like, and mixtures thereof are included, among which 1,3-butadiene or isoprene is preferable. Preferred conjugated diene rubbers are high cis-1,4-polybutadiene, low cis-1,4-polybutadiene, high cis-1,
4-polyisoprene can be mentioned.

The vinyl aromatic hydrocarbon monomer includes styrene, vinyltoluene, α-methylstyrene, p-methylstyrene, t-butylstyrene and the like, among which styrene is preferred. Preferred conjugated diene / vinyl aromatic hydrocarbon copolymer rubbers include styrene-butadiene rubber.

The microstructure of a conjugated diene / vinyl aromatic hydrocarbon co-heavy rubber, for example, styrene-butadiene rubber, may have a composition distribution of random type, block type or intermediate type, but is preferably random type. ,
The vinyl content of the butadiene part is usually about 20 to 80%, and the weight ratio of styrene / butadiene is usually 10/9.
It is in the range of 0 to 60/40. As the random styrene-phthaldiene rubber, those obtained by emulsion polymerization or solution polymerization are preferably used.

The conjugated diene rubber and the conjugated diene / vinyl aromatic hydrocarbon copolymer rubber can be easily obtained by polymerizing or copolymerizing a predetermined amount of the above-mentioned monomer with, for example, an organolithium compound as an initiator. The organolithium compound includes all generally known compounds and is not particularly limited, and examples thereof include methyllithium, ethyllithium, propyllithium, n-butyllithium, sec.
-Alkyl lithium typified by butyl thylium, tert-butyl lithium, hexyl lithium, octyl lithium, etc., Aryl lithium typified by phenyl lithium, tolyl lithium, lithium naphthylide, alkenyl lithium typified by vinyl lithium, propenyl lithium, etc. , Alkylenedilithium represented by tetramethylenedilithium, pentamethylenedilithium, hexamethylenedilithium, heptamethylenedilithium, decamethylenedilithium, and the like.

The amount of organolithium compound will depend on the desired molecular weight of the rubber, but is generally 100% monomer.
With respect to g, 0.05 to 15 mmol, preferably 0.1
-10 mmol is used. If it exceeds 15 mmol, it is difficult to obtain a high molecular weight compound,
If it is less than the above range, it may be inactivated by impurities in the polymerization system and the polymerization may not proceed, which is not preferable.

In the conjugated diene rubber or the conjugated diene / vinyl aromatic hydrocarbon copolymer rubber in the rubber composition of the present invention, a randomizer is preferably used when it is desired to obtain a rubber having a desired molecular structure. The term "randomizer" as used herein refers to control of the microstructure of the rubber, such as the increase of 1,2 bonds in the butadiene part of polybutadiene or styrene-butadiene rubber, and the composition of the monomer units of the conjugated diene / vinyl aromatic hydrocarbon copolymer rubber. It is a compound having a function of controlling distribution, for example, randomizing butadiene units and styrene units of styrene-butadiene rubber.

The randomizer is not particularly limited, but includes all commonly used randomizers. Examples of the randomizer used include ethers such as tetrahydrofuran (THF), tetrahydropyran, 1,4-dioxane, monoglycol methyl ether (monoglyme), diglycol methyl ether (diglyme), triglycol methyl ether (triglyme). , And oligomeric oxolanyl alkane compounds such as bis (2-oxolanyl) methane, 2,2-bis (2-oxolanyl) propane, 1,1-bis (2-oxolanyl) ethane, 2,2-bis (5 -, methyl-2-oxolanyl) propane, further tertiary amine compounds such as triethylamine, tripropylamine, ^{tributylamine, N, N, N ',} N' - tetramethylethylenediamine (TMEDA), dipiperidinoethane etc. Included .

The randomizer is used in an amount of 0.01 to 1000 mol per mol of the organic lithium compound.

The polymerization can be carried out at any temperature within the range of about -80 to 150 ° C, but a temperature of -20 to 100 ° C is preferred. The polymerization reaction can be carried out under a generated pressure, but it is usually desirable to operate at a pressure sufficient to keep the monomer substantially in the liquid phase. That is, the pressure depends on the individual substance to be polymerized, the diluent used and the polymerization temperature,
Higher pressures can be used if desired, and such pressures are obtained in any suitable manner such as pressurizing the reactor with a gas inert to the polymerization reaction.

As the polymerization method, either bulk polymerization or solution polymerization can be adopted, but it is preferable to use solution polymerization in an inert solvent. Normally, the solvent is preferably a liquid under the conditions of the polymerization reaction, and an aliphatic, alicyclic or aromatic hydrocarbon is used. Examples of preferred inert solvents include propane, butane, pentane, hexane, heptane, isooctane, cyclopentane, cyclohexane, methylcyclohexane, decane, benzene, toluene, xylene,
Examples thereof include naphthalene and tetrahydronaphthalene.
You may use these solvents as a mixture of 2 or more types.
In general, it is preferred to remove water, oxygen, carbon dioxide and other catalyst poisons from all materials involved in the polymerization process such as initiator components, solvents, monomers.

The silane coupling agent used in the rubber composition of the present invention is selected from the group consisting of the compounds represented by the general formulas (II) and (III). Examples of the compound of the general formula (II) include bis- (3-triethoxysilylpropyl) -tetrasulfide and γ-mercapto-propyltrimethoxysilane.
Examples of the compound of I) include 3-trimethoxysilylpropyl-N, N-dimethylthiocarbamoyl-tetrasulfide, trimethoxysilylpropyl-mercaptobenzothiazole tetrasulfide, triethoxysilylpropyl-methacrylate-monosulfide, dimethoxymethylsilyl. Propyl-N, N-dimethylthiocarbamoyl-tetrasulfide and the like are included. Among them, bis- (3-triethoxysilylpropyl) -tetrasulfide and γ-mercapto-propyltrimethoxysilane are preferable from the viewpoint of low hysteresis loss effect.

The hydrazide compound used in the rubber composition of the present invention functions as a loss-reducing agent and has the general formula (IV)
, (V) and (VI). Examples of the compound of the general formula (IV) include isophthalic acid dihydrazide, terephthalic acid dihydrazide, azelaic acid dihydrazide, azepinic acid dihydrazide, succinic acid dihydrazide, icosanoic acid dihydrazide, 7,11-
Octadecadiene-1,18-dicarbohydrazide,
1,3-bis (hydrazinocarboethyl) -5-isopropylhydantoin and the like can be mentioned, and examples of the compound of the general formula (V) include 2-hydroxy-3-.
Naphthoic acid hydrazide, anthranilic acid hydrazide, salicylic acid hydrazide, 4-hydroxybenzoic acid hydrazide, etc. are included, and as the compound of general formula (VI),
Examples thereof include carbodihydrazide and isonicotinic acid hydrazide. Of these, 2-hydroxy-3-naphthoic acid hydrazide is preferable from the viewpoint of low hysteresis loss effect.

The thiadiazole compound used in the rubber composition of the present invention functions as a loss-reducing agent and is selected from the group consisting of the compounds represented by the general formula (VII). Examples of the compound of the general formula (VII) include 2,5-dimercapto-1,3,4-thiadiazole, 2-amino-5-mercapto-1,3,4-thiadiazole, 2-amino-
Examples thereof include 5-trifluoromethyl-1,3,4-thiadiazole. Among them, 2,5-dimercapto-1,3,4-thiadiazole is preferable from the viewpoint of low hysteresis loss.

The compounding amount of the compounds represented by the general formulas (II) to (VII) is 0.05 to 100 parts by weight of the rubber.
The amount is 5.0 parts by weight, preferably 0.1 to 1.0 parts by weight. If the amount is less than 0.05 parts by weight, a sufficient effect cannot be obtained, and if it exceeds 5.0 parts by weight, it is not preferable from the viewpoint of balance with other rubber physical properties.

In the rubber composition of the present invention, the functional group of carbon black specified by the X characteristic reacts with the coupling agent and / or the loss-reducing agent, and one end of these additives is a conjugated diene-based synthetic rubber. It is considered that the wet skid property is improved by interacting with the above to improve the low hysteresis loss property and due to the reinforcing effect by this interaction.

The rubber composition of the present invention contains a compounding agent usually used in the rubber industry, such as other reinforcing fillers, vulcanizing agents, stearic acid, zinc oxide, vulcanization accelerators, antiaging agents, A softening agent and the like can be appropriately added.

The rubber composition of the present invention is preferably used as a tread rubber for tires, a side rubber, especially a tread rubber, but also for other rubber products required to have low hysteresis loss, such as belts and shock absorbers. used.

[0043]

EXAMPLES The present invention will be described in more detail with reference to examples below, but the present invention is not limited to these examples as long as the gist of the present invention is not exceeded.

Various measurements are as follows. · N in compliance with the measurement ASTM D3037 of ₂ SA (nitrogen adsorption specific surface area), the nitrogen specific surface area of the carbon black per 1g than adsorption amount of (N ^₂₎ (m ₂₎
I asked. -> C = O Measurement of functional group concentration 1) Preparation of oxime-containing carbon black Two Erlenmeyer flasks containing about 1.5 g of carbon black were prepared, and one flask was charged with 20 g of pyridine and 1 g of hydroxylamine hydrochloride. The melted solution is added with 20 ml of pyridine in the other flask. A condenser tube with a ball is attached to the upper part of the Erlenmeyer flask, and a calcium chloride tube and a deoxidizer are connected to the condenser tube. The whole apparatus is replaced by flowing nitrogen gas to create a nitrogen atmosphere.

The flask is placed in an oil bath maintained at 100 ° C. and reacted at this temperature for 16 hours. After completion of the reaction, 50 ml of 3N hydrochloric acid is added while cooling the reaction product to neutralize excess hydroxylamine. The content is suction filtered to separate the oxime carbon black, about 300 ml
Wash with distilled water. This is No. Transfer to 5B filter paper,
Wash with an additional 300 ml of distilled water.

The oxime-converted carbon black after washing was
Put it in a drier kept at 05 ° C and dry it to a constant weight to prepare an oxime carbon black (the same operation is performed with a blank.) 2) Preparation of a sample for quantitative determination of nitrogen content Oxime carbon black About 0.2 g of the control carbon black is precisely weighed and placed in a semi-micro Kjeldahl decomposition bottle. Calcium sulfate 2.5 for each
g, 0.02 g of mercuric oxide, and finally 4 m of concentrated sulfuric acid
Add l.

The decomposition bottle is attached to a semi-micro Kjeldahl decomposition device, and tap water is poured into the exhaust gas suction aspirator to heat it. The intensity of the flame is weakened at first so that the contents of the decomposition bottle do not boil, and gradually increases as the white smoke in the decomposition bottle decreases, and the heat is increased to the extent of boiling. After the contents of the decomposition bottle become completely transparent, ignite for another hour. Turn off the heat and allow to cool to room temperature, remove the bottle from the decomposition apparatus and add about 10 ml of distilled water little by little. Then, the contents are put into a sample flask of a semi-micro Kjeldahl nitrogen distillation apparatus. A nitrogen content quantitative sample flask is attached to a distillation apparatus, and a beaker containing 5 ml of a 2% boric acid solution is connected to the outlet of a condenser tube with a bulb of the distillation apparatus. From the alkali inlet of the distillation apparatus, sodium hydroxide / sodium thiosulfate (50% / 5%) solution 2
Inject 5 ml, close the inlet and the vapor port, and perform distillation for 9 minutes.

1% of a 2% boric acid solution in which ammonia is dissolved
Titrate with 100N hydrochloric acid. Using an ammonium sulfate solution with a known amount of nitrogen, perform the above-mentioned operation to prepare a calibration curve, determine the milliequivalent of nitrogen from the titration amount of the sample and the calibration curve, and calculate the milliequivalent of> C = O functional group per 1 g of carbon black. Calculate (meq / g).

[0049] -Measurement of hysteresis loss property The internal loss (tan δ) was measured using a viscoelasticity spectrometer manufactured by Iwamoto Seisakusho Co., Ltd. under the conditions of a dynamic strain of tension of 1%, a frequency of 50 Hz and 60 ° C. The test piece is a slab sheet having a thickness of about 2 mm and a width of 5 mm.
The initial load was 160 g with the distance between the samples being 2 cm. The value of tan δ is represented by an index with Comparative Example 6 set to 100, and the smaller the value, the smaller the hysteresis loss property, which is preferable. -Measurement of wet skid property For evaluation of wet skid property, a skid tester manufactured by Stanley London, England was used to measure slip resistance at room temperature on a concrete road surface whose surface was wet with water. The value is represented by an index with Comparative Example 6 as 100, and the larger the value, the better. -Measurement of rolling resistance performance A rubber composition was applied to a tread of a passenger car tire of 195 / 65R15 size, an internal pressure of 2.0 kg, and a load of 440.
A tire with 6 kg of rim and 6 JJ is brought into contact with a drum having an outer diameter of 1.7 m to rotate the drum, and a speed of 120 km / h.
After ascending, the drum was coasted, and the value was calculated from the moment of inertia when the speed was 80 km / hour. The numerical value is represented by an index with Comparative Example 6 as 100, and the larger the value, the better.

[0050] ・ Measurement of wet skid performance of tires The tires are mounted on a test trailer and run on a wet asphalt dense-grained road surface in accordance with the method determined by the running performance on wet road surfaces, according to the UTQGS (tire quality grade standard) of the United States. The frictional resistance when the rotation of the tire was locked was measured. The numerical value is represented by an index with Comparative Example 6 as 100,
The big method is good. Carbon black used in Comparative Examples and Examples 1) Carbon black used in Comparative Examples Carbon black A (control), B, C, D, E
Both F and F are normal furnace blacks, and ASTM codes N330, N660, N550 and N3, respectively.
39, N220 and N110. 2) Carbon black G used in the examples is carbon black A obtained by oxidizing carbon black A at room temperature for 3 hours in an ozone atmosphere.

Carbon black H is carbon black G
Was heat-treated under nitrogen at 450 ° C. for 1 hour.

Carbon black I is produced by a gas furnace method using LPG as a raw material.

Carbon black J is a channel type carbon black of CK-3 (trade name, manufactured by Degussa).

Carbon black K is carbon black J
Is oxidized at room temperature for 3 hours in an ozone atmosphere.

Carbon black L is carbon black K
Was heat-treated under nitrogen at 450 ° C. for 1 hour.

Carbon black M is Special B
This is a channel-type carbon black of rack 4A (trade name, manufactured by Degussa), which is oxidized.

[Example 1] A rubber composition was prepared using carbon black J, natural rubber, SBR, and silane coupling agent Si69 (trade name, manufactured by Degussa Co., Ltd.) according to the formulations shown in Tables 2 and 3. Vulcanization was performed at 150 ° C for 40 minutes. The results of measuring the characteristics of carbon black J are shown in Table 1. Table 3 shows the evaluation results of physical properties such as hysteresis loss property (tan δ) and wet skid property of the vulcanized product. In addition, the rubber composition used in the tread was 195 /
Table 4 shows the results of evaluation of rolling resistance performance, wet skid performance and the like of a 65R15 size passenger car tire.

[Examples 2 to 10] In the same manner as in Example 1, various carbon blacks (GM) and various additives were used to obtain rubber compositions and tires. The results of measuring the properties of each carbon black are shown in Table 1, the results of measuring the physical properties of each vulcanized product are shown in Table 3, and the results of evaluating the performance of each tire are shown in Table 4.

Comparative Examples 1 and 6 A rubber composition was prepared in the same manner as in Example 1 except that carbon black A was used in comparative example 1, carbon black J was used in comparative example 6, and no additive was used. Things and tires were obtained. The results of measuring the properties of each carbon black are shown in Table 1, the results of measuring the physical properties of each vulcanized product are shown in Table 3, and the results of evaluating the performance of each tire are shown in Table 4.

Comparative Examples 2 to 5, Comparative Examples 7 to 11 In the same manner as in Example 1, various carbon blacks (A to F) and various additives were used to obtain rubber compositions and tires. The results of measuring the properties of each carbon black are shown in Table 1, the results of measuring the physical properties of each vulcanized product are shown in Table 3, and the results of evaluating the performance of each tire are shown in Table 4.

[0061]

[Table 1]

[0062]

[Table 2]

[0063]

[Table 3]

[0064]

[Table 4]

As shown in Table 3, it can be seen that the rubber composition of the present invention is extremely excellent in low hysteresis loss and at the same time has a high level of wet skid. Further, as shown in Table 4, it is clear that the pneumatic tire using the rubber composition of the present invention has significantly improved low rolling resistance performance and excellent wet skid performance.

As can be seen from the comparative examples, when the carbon black outside the scope of the claims is used, the rubber compositions obtained are low regardless of the presence or absence of the specific additive (Comparative Examples 1 to 5 and 7 to 11). Both the hysteresis loss property and the wet skid property are inferior, and similarly, the tire using this rubber composition cannot simultaneously satisfy the low rolling resistance property and the wet skid property. When carbon black satisfying the claims is used, if the additive is not present (Comparative Example 6), the obtained rubber composition and tire cannot obtain the effect.

[0067]

Since the rubber composition of the present invention has the above constitution, the low hysteresis loss property is remarkably improved, and at the same time, the wet skid property is at a high level, and the pneumatic tire using this rubber composition is also improved. Has significantly improved low rolling resistance performance and has a high level of wet skid performance.

Continuation of front page (51) Int.Cl. ⁷ identification code FI C08K 9/02 C08K 5/54 (58) Fields investigated (Int.Cl. ⁷ , DB name) C08L ^7/ 00-21/02

Claims (8)

(57) [Claims] 1. To 100 parts by weight of at least one rubber selected from the group consisting of conjugated diene-based synthetic rubber and natural rubber, 30 to 30 parts of carbon black having the characteristic represented by the following general formula (I) is used. 120 parts by weight, a silane coupling agent selected from the group consisting of compounds represented by the following general formulas (II) and (III), represented by the following general formulas (IV), (V) and (VI) A hydrazide compound selected from the group consisting of compounds represented by the following general formula (VI
A rubber composition comprising 0.05 to 5.0 parts by weight of at least one thiadiazole compound selected from the group consisting of compounds represented by I). General formula (I) [> C = O functional group concentration] / N ₂ SA ≧ 4.0 × 10 ⁻⁴ (where [> C═O functional group concentration] reacts with hydroxylamine to form an oxime. Functional group concentration (meq /
g), and N ₂ SA is a nitrogen adsorption specific surface area (m ² / m
g) is represented. ] [Chemical 1] (In the formula, X ¹ is a nitroso group, a mercapto group, an amino group,
Represents an epoxy group, a vinyl group, a chlorine atom or an imide group,
Y ¹ represents an alkoxy group having 1 to 4 carbon atoms or a chlorine atom, Y ² represents an alkyl group having 1 to 4 carbon atoms, and a is 1
Is an integer of 3 and b is an integer of 0 to 2, a + b
= 3, and n and m each represent an integer of 1 to 6. ) [Chemical 2] (In the formula, X ² is represented by the following formula: (Y ¹ represents an alkoxy group having 1 to 4 carbon atoms or a chlorine atom, Y ² represents an alkyl group having 1 to 4 carbon atoms, a is an integer of 1 to 3, and b is an integer of 0 to 2. Represent each, a +
b = 3, and n and m each represent an integer of 1 to 6. ) [Chemical 4] [Chemical 5] [Chemical 6] (In the formula, A is an aromatic ring, a saturated or unsaturated hydantoin ring,
Or a linear saturated or unsaturated alkyl group having 1 to 18 carbon atoms, n is 0 or 1, B is an aromatic ring, Z is a hydroxyl group or an amino group, L is a pyridyl group or hydrazino. Represents a group. ) [Chemical 7] (In the formula, R ¹ represents a mercapto group, and R ² represents a mercapto group, an amino group, or a trifluoromethyl group.) 2. The rubber composition according to claim 1, wherein the conjugated diene-based synthetic rubber is polybutadiene rubber and / or styrene-butadiene rubber. 3. The carbon black is a carbon black obtained by subjecting at least one selected from the group consisting of furnace black and channel type carbon black to an oxidizing treatment by an oxidizing means. The rubber composition according to claim 1. 4. The carbon black is at least one selected from the group consisting of furnace black and channel-type carbon black, which is subjected to an oxidation treatment by an oxidizing means, and a heat treatment at a temperature of 100 to 900 ° C. The rubber composition according to claim 1, which is the obtained carbon black. 5. A pneumatic tire having a tread portion, a sidewall portion and a bead portion, wherein the tread portion has 100 parts by weight of at least one rubber selected from the group consisting of conjugated diene synthetic rubber and natural rubber. On the other hand, a silane selected from the group consisting of 30 to 120 parts by weight of carbon black having the characteristic represented by the general formula (I) and the compound represented by the general formulas (II) and (III). A coupling agent, a hydrazide compound selected from the group consisting of compounds represented by the general formulas (IV), (V) and (VI), and the general formula (VII)
A pneumatic tire comprising a rubber composition containing at least one thiadiazole compound selected from the group consisting of: and 0.05 to 5.0 parts by weight. 6. The pneumatic tire according to claim 5, wherein the conjugated diene-based synthetic rubber is polybutadiene rubber and / or styrene-butadiene rubber. 7. The carbon black is a carbon black obtained by subjecting at least one selected from the group consisting of furnace black and channel type carbon black to an oxidizing treatment by an oxidizing means. The pneumatic tire according to claim 5. 8. The carbon black is at least one selected from the group consisting of furnace black and channel-type carbon black, subjected to an oxidation treatment by an oxidizing means, and further subjected to a heat treatment at a temperature of 100 to 900 ° C. The pneumatic tire according to claim 5, which is the obtained carbon black.