JP2562339B2 - Low heat-generating rubber composition - Google Patents

Description

Description: TECHNICAL FIELD OF THE INVENTION The present invention relates to a low heat-generating rubber composition, and more specifically, a low heat-generating property with significantly improved heat-generating property without impairing wear resistance, skid resistance and the like. It relates to a rubber composition.

[Prior art]

To meet the social demand for resource and energy conservation,
In the rubber industry, especially in the tire industry, fuel-efficient tires have been actively developed for several years.
A low heat-generating rubber composition is indispensable for the development of such a fuel-efficient tire, and many inventions belonging to this field have been issued recently.

For example, JP-A-55-12133 and JP-A-56-127650.
In Japanese Patent Publication, high vinyl polybutadiene rubber (V-BR)
However, in JP-A-57-55204 and JP-A-57-73030, a high vinyl styrene-butadiene copolymer rubber (V-
SBR) has been proposed and shown to be effective in improving grip performance and heat generation.

Further, in JP-A-59-117514, JP-A-61-103902, JP-A-61-14214, and JP-A-61-141741, benzophenone, isocyanate, etc. are contained in the molecular chain of the polymer. A method for reducing the heat buildup of a rubber composition by using a modified polymer having a functional group introduced therein has been disclosed.

However, even if these V-BR, V-SBR or modified polymers are used, the recent requirement for low heat buildup has not been sufficiently satisfied, and a rubber composition having even lower heat buildup is desired. .

On the other hand, as a method for obtaining a rubber composition having a low exothermicity, a method of using carbon black having a large particle diameter or a method of reducing the compounding amount of carbon black is generally known. It is not practical because it has poor breaking strength and wear resistance. In addition, Japanese public Sho 59
-2451 discloses that carbon black having a wide distribution of aggregates improves the heat generation property, but even this carbon black cannot provide a sufficiently satisfactory heat generation property.

Further, Japanese Examined Patent Publication No. 50-38181 and U.S. Pat. No. 2815856.
It is described in the specification etc. that the heat buildup of the rubber composition is improved by adding nitrosoquinolines, nitrosoanilines and the like. However, such nitroso compounds, when added to polyisoprene rubber,
There are drawbacks such that the polymer has a large peptizing action and the abrasion resistance of the rubber composition is reduced. Further, when it is added to other diene rubbers, it cannot be said that the exothermic property is sufficiently improved.

As described above, although many inventions have been made to improve the heat buildup of rubber compositions, a low heat buildup rubber composition that sufficiently satisfies the recent high requirements for fuel-efficient tires has not been obtained. At present, the invention of such a rubber composition has been very strongly desired.

The present inventors have used a so-called modified polymer having a functional group introduced into the polymer molecular chain and carbon black having high surface activity, which is said to be effective in improving wear resistance, to improve heat generation. Has been found to be significantly improved, and the present invention has been completed.

That is, the modified polymer in which a functional group is introduced into the polymer molecular chain is effective in improving heat generation as shown in the above-mentioned publication, while high surface activity, that is, 1200
It is known that carbon black, which produces a large amount of hydrogen (H ₂ amount) at high temperatures up to 1300 ° C, is effective in improving wear resistance.
Although disclosed in Japanese Patent Laid-Open No. 61-207452, all of these are merely inventions focusing on the polymer itself or the carbon black itself. The present inventors believe that the characteristics of such a modified polymer or activated carbon black are manifested due to the stronger interaction at the interface between the polymer and carbon black, and the modified polymer and carbon black having high surface activity are used at the same time. It was thought that the polymer / carbon black interaction would be further strengthened, and the exothermicity, breaking strength, etc. would be further improved. As a result, when the modified polymer and carbon black having high surface activity are used in combination, the effect of improving heat generation obtained by the modified polymer (A) and the effect obtained by activated carbon black (B) are added together. (A) +
The effect of improving heat generation (synergistic effect), which is larger than that of (B) (additive effect), can be found, and the present invention has been achieved.

[Object of the Invention]

Therefore, it is an object of the present invention to provide a low heat buildup rubber composition having significantly improved heat buildup without impairing wear resistance, skid resistance and the like.

〔The invention's effect〕

Therefore, the present invention provides a rubber-like polymer having an alkali metal and / or an alkaline earth metal added thereto, Organic compounds having a bond (in the formula, X represents an O or S atom), benzophenones having an amino group and / or a substituted amino group, thiobenzophenones having an amino group and / or a substituted amino group, a general formula (Wherein R represents hydrogen or an organic group, and n represents an integer of 1 to 4), an aminobenzene derivative, an isocyanate compound, a monofunctional or difunctional active tin compound, and a reactivity having a thioether group. A raw rubber 100 containing at least 30% by weight of a polymer obtained by reacting one or more compounds selected from compounds, carbodiimides, carbon disulfide, xanthogen compounds and dithioacid compounds.
With respect to parts by weight, the nitrogen adsorption specific surface area (N ₂ SA) is 75 m ² / g or more and the amount of hydrogen (H ₂ amount) generated at 1300 ° C is the most frequent mode diameter (Dst, m)) and carbon black having the relationship of the following formula: 20 to 150 parts by weight, and a low heat-generating rubber composition characterized by the above.

H ₂ > 3.74-0.02 (Dst) Hereinafter, the configuration of the present invention will be described in detail.

(1) Raw rubber.

Alkali metal and / or alkaline earth metal addition rubber-like polymer, in the molecule Organic compounds having a bond (in the formula, X represents an O or S atom), benzophenones having an amino group and / or a substituted amino group, thiobenzophenones having an amino group and / or a substituted amino group, a general formula (Wherein R represents hydrogen or an organic group, and n represents an integer of 1 to 4), a reaction having an aminobenzene derivative, an isocyanate compound, a monofunctional or bifunctional active tin compound, and a thioether group. Of at least 30% by weight of a polymer obtained by reacting with one or more compounds selected from a polymerizable compound, carbodiimides, carbon disulfide, a xanthogen compound and a dithioacid compound.
When the content of the obtained polymer is less than 30% by weight, the heat buildup is not sufficiently improved even when active carbon black is used in combination. To produce this polymer, 0.2 to 5 moles of the one or more compounds are used per mole of the rubbery polymer,
The reaction is preferably 0.5 to 2 mol. Introduction of a functional group by this reaction, after the polymerization of the rubber-like polymer,
Although it can be easily carried out by adding these compounds, it may be carried out by a method such as polymerizing with an initiator having a functional group, and any method can be used as long as the functional group is introduced into the polymer chain. It may be.

(A) Rubber-like polymer.

The rubbery polymer into which the functional group is introduced is a diene polymer produced by a solution polymerization method using an alkali metal and / or alkaline earth metal catalyst. For example, it is a homopolymer or copolymer of a conjugated diene monomer containing 1,3-butadiene, isoprene, 1,3-pentadiene, 1,3-hexadiene and the like. In particular, when used for tires, polybutadiene rubber, styrene-butadiene copolymer rubber, and polyisoprene rubber are preferable, but not limited to these.

(B) In the molecule An organic compound having a bond (in the formula, X represents an O or S atom).

Examples include formamide, N, N-dimethylformamide, N, N-diethylformamide, acetamide, N, N
-Dimethylacetamide, N, N-diethylacetamide, aminoacetamide, N, N-dimethyl-N ', N'-
Dimethylaminoacetamide, N ', N'-dimethylaminoacetamide, N'-ethylaminoacetamide, N,
N-dimethyl-N'-ethylaminoacetamide, N, N-
Dimethylaminoacetamide, N-phenyldiacetamide, acrylamide, N, N-dimethylacrylamide, N, N-dimethylmethacrylamidopropionamide, N, N-dimethylpropionamide, 4-pyridylamide, N, N-dimethyl-4- Pyridylamide, benzamide, N-ethylbenzamide, N-phenylbenzamide, N, N-dimethylbenzamide, p-aminobenzamide, N ', N'-(p-dimethylamino) benzamide, N'N '-(p-diethylamino ) Benzamide,
N '-(p-methylamino) benzamide, N'-(p
-Ethylamino) benzamide, N, NP-dimethyl-N '
-(P-ethylamino) benzamide, N, N-dimethyl-N ', N'-(p-diethylamino) benzamide, N,
N-dimethyl-p-aminobenzamide, N-methyldibenzamide, N-acetyl-N-2-naphthylbenzamide, succinic acid amide, maleic acid amide, phthalic acid amide, N, N, N ', N'-tetramethyl Maleic acid eye, N, N, N ', N'-tetramethylphthalic acid amide, succinimide, N-methylsuccinimide, maleimide, N-
Methylmaleimide, phthalimide, N-methylphthalimide, oxide, N, N, N ', N'-tetramethyloxamide, N, N-dimethyl-p-amino-benzalacetamide, nicotinamide, N, N-diethylnicotine Amide, 1,2-cyclohexanedicarboximide, N-methyl-1,2-cyclohexanedicarboximide, methyl carbamate, N-methyl-methyl carbamate, N, N-
Diethyl-ethyl carbamate, ethyl carbanylate,
Amides, imides such as ethyl p-N, N-diethylamino-carbanilate; urea, N, N'-dimethylurea, N,
Urea such as N, N ', N'-tetramethylurea; formanilide, N-methylacetanilide, aminoacetanilide, benzanilide, p, p'-di (N, N-diethylaminobenzanilide and other anilides; ε- Caprolactam, N-methyl-ε-caprolactam, N-acetyl-
ε-caprolactam, 2-pyrrolidone, N-methyl-2
-Pyrrolidone, N-acetyl-2-pyrrolidone, 2-piperidone, N-methyl-2-piperidone, 2-quinolone, N-methyl-2-quinolone, 2-indolinone, N
-Lactams such as methyl-2-indolinone; isocyanuric acids such as isocyanuric acid, N, N ', N "-trimethylisocyanuric acid, and the like, and sulfur-containing compounds corresponding thereto. Particularly preferred compounds are nitrogen-containing alkyl groups. Is a compound bound to.

(C) Benzophenones and thiobenzophenones.

Benzophenones and / or thiobenzophenones having an amino group and / or a substituted amino group include 4-aminobenzophenone, 4-dimethylaminobenzophenone, 4-dimethylamino-4′-methylbenzophenone, 4,4′-diaminobenzophenone, 4,4'-bis (dimethylamino) benzophenone, 4,4'-bis (diethylamino) benzophenone, 4,4'-bis (ethylamino) benzophenone, 3,3'-dimethyl-4,4'-bis (diethylamino) ) Benzophenone, 3,3'-dimethoxy-4,4'-bis (dimethylamino) benzophenone,
Examples include 3,3 ′, 5,5′-tetraaminobenzophenone, 2,4,6-triaminobenzophenone, 3,3 ′, 5,5′-tetra (diethylamino) benzophenone, and their corresponding thiobenzophenones. . As the substituted amino group, those having an alkyl group, particularly a dialkyl-substituted amino group are preferred. Substituents other than the amino group and the substituted amino group may be present as long as they do not adversely affect the reaction.

(D) Aminobenzene derivative.

 It is a compound represented by the following formula.

In the formula, R is hydrogen or an alkyl group having 1 to 5 carbon atoms,
A cycloalkyl group and an alkenyl group are shown. X represents a halogen, an ester group or a nitrile group. n represents an integer of 1 to 4.

Examples of this compound include p-aminoethylbenzoate, p-aminobutylbenzoate, o-amino-p-methylethylbenzoate, o-aminomethylbenzoate, p-aminopropylbenzoate, o-aminobenzonitrile, p-amino. Benzonitrile, m-
Examples thereof include aminobenzonitrile.

Further, N-bis (trimethylsilyl) aminobenzene derivatives obtained by trimethylsilylating the amino groups of these aminobenzene derivatives can be mentioned. As a specific example, p-
N-bis (trimethylsilyl) aminoethylbenzoate, p-N-bis (trimethylsilyl) aminobutylbenzoate, o-N-bis (trimethylsilyl) amino-p-methyl-ethylbenzoate, o-N-bis (trimethylsilyl) methylbenzoate, Examples thereof include p-N-bis (trimethylsilyl) propylbenzoate, o-bis (trimethylsilyl) benzonitrile, p-bis (trimethylsilyl) benzonitrile and m-bis (trimethylsilyl) benzonitrile.

(E) Isocyanate compound.

For example, phenyl isocyanate, hexamethylene diisocyanate, 2,4-tolylene diisocyanate, 2,6
-Tolylene diisocyanate, diphenylmethane diisocyanate, naphthalene diisocyanate, tolylene diisocyanate, triphenylmethane triisocyanate, polymeric diphenylmethane diisocyanate,
p-Phenylenediisocyanate, tris (isocyanatophenyl) thiophosphate, xylylenediisocyanate, benzene-1,2,4-triisocyanate, naphthalene-1,2,5,7-tetraisocyanate, naphthalene-1 , 3,7-Triisocyanate, various aromatic polyisocyanates, or dimers or trimers of various isocyanate compounds, and adducts obtained by reacting the above isocyanates with polyols or polyamines, alone or in combination of two kinds. Used above.

(F) Active tin compound.

As the monofunctional or bifunctional active tin compound, 1
It is a compound containing one or two halogen / tin bonds, alkoxy / tin engagements, aryl / tin bonds, or benzyl / tin bonds in the molecule. Specifically, trimethyltin chloride, tributyltin chloride, trioctyltin chloride, tributyltin bromide, dibutyltin dichloride, dioctyltin chloride, phenyltributyltin, methoxytributyltin, etc. are used.

(G) A reactive compound having a thioether group.

As the reactive compound having a thioether group, all compounds capable of reacting with a living terminal and introducing a thioether group into a polymer molecule are used, but preferably a general formula, (Wherein R represents alkyl, allyl, R ′ represents alkylene, arylene, M represents oxygen or sulfur, X represents alkyl, allyl or alkoxy), and (In the formula, R, R ', and M have the same meanings as in the above formula, X represents alkylene, arylene, alkyleneoxy, oxygen, and sulfur. When X represents these, n is 2, and X is When representing a polyhydric alcohol residue, n represents a number equal to the number of alcohol groups), and is one or a mixture of two or more compounds selected from the group consisting of: Examples of these compounds include methylacetone, 1-butylthiohexanone-3, 2-laurylthiophenyl ketone, 2-octylthioethylbenzyl ketone, 2-phenylthiophenyl ketone, p-laurylthiobenzophenone, p-laurylthio. Acetophenone, methyl methylthioglycolate, β-ethylthiopropionate ethyl, α-ethylthiopropionate ethyl, β-propylthiopropionate hexyl, β-ethylthiopropionate lauryl, β
-Myristyl octylthiopropionate, β-lauryl thiopropionate stearyl, β-stearyl thiopropionate stearyl, β-benzylthiopropionate stearyl, β-p-tolylthiopropionate stearyl, β-2,5-xylylthiopropionate Stearyl acid,
Methyl p-laurylthiobenzoate, Methyl o-laurylthiobenzoate, Benzyl p-laurylthiobenzoate, p
-Phenyl laurylthiobenzoate, ethyl γ-methylthiobutyrate, ethyl 2-methylthioethanecarbodithioate,
Dimethyl thiodiglycolate, β, β′-dimethyl thiodipropionate, β, β′-dilauryl thiodipropionate, β, β′-dimyristyl thiodipropionate,
β, β'-Distearyl thiodipropionate, α, α '
-Dimethyl thiodipropionate, dimethyl thiobisdithioglycolate, 1,6-dimethylthiohexadione-2,
5, ethylenebismethylthioglycolate, glycerin-tri-β-laurylthiopropionate, pentaerythritol-tetrakis-βlaurylthiopropionate, methylthioglycolic anhydride, methylthiodithioglycolic anhydride and the like.

(H) Carbodiimides.

As the carbodiimides, a disubstituted carbodiimide compound having a general formula -N = C = N- bond or a general formula> N
A 2-substituted cyanamide compound having a -C≡N bond,
It is a compound containing a dialkylcarbodiimide, an alkylallyl-carbodiimide, a diarylcarbodiimide, a dialkylcyanamide, an alkylarylcyanamide, and a diarylcyanamide, and is used as one kind or as a mixture of two or more kinds.

For example, dimethylcarbodiimide, diethylcarbodiimide, dipropylcarbodiimide, dibutylcarbodiimide, dihexylcarbodiimide, dicyclohexylcarbodiimide, dibenzylcarbodiimide, diphenylcarbodiimide, methylpropylcarbodiimide, butylcyclohexylcarbodiimide, ethylbenzylcarbodiimide, propylphenylcarbodiimide, phenylbenzylcarbodiimide, dimethyl. Cyanamide, diethylcyanamide, dipropylcyanamide, dibutylcyanamide, dihexylcyanamide, dicyclohexylcyanamide, dibenzylcyanamide, diphenylcyanamide, methylpropylcyanamide, butylcyclohexylcyanamide, ethylbenzylcyanamide, propylphenylcyanamide, phenylcyanamide And the like benzyl cyanamide. Of these, particularly preferred are dicyclohexylcarbodiimide, diphenylcarbodiimide and diphenylcyanamide.

(I) Carbon disulfide.

 General commercially available carbon disulfide may be used.

(J) A xanthogen compound.

The xanthogen compound has the general formula A compound having, for example, methylxanthate, ethylxanthate, n-propylxanthate, isopropylxanthate, n-butylxanthate, sec-butylxanthate, n-hexylxanthate, n-octylxanthate, Such as alkylxanthogenic acid, phenylxanthogenic acid, p-
Allylxanthogenic acids such as tolylxanthogenic acid and lithium, sodium and potassium salts of these xanthogenic acids and dimethylxanthogen disulfide, diethylxanthogen disulfide, di-n-propylxanthogen disulfide, diisopropylxanthogen disulfide, di-n-butylxanthogen disulfide, di -Sec-Butylxanthogen disulfide, di-
Xanthogen disulfides such as n-hexylxanthogen disulfide, diphenylxanthogen disulfide and di-p-tolylxanthogen disulfide are preferably used. Among these, particularly preferable are xanthogen disulfides such as dimethylxanthogen disulfide, diisopropylxanthogen disulfide, di-n-hexylxanthogen disulfide, and diphenylxanthogen disulfide.

(K) A dithio acid compound.

As the dithio acid compound, a general formula, Compounds having a group, such as dithioformic acid, dithioacetic acid, ethanecarbodithioic acid, isobutanecarbodithioic acid and isopentanecarbodithioic acid, and their lithium, sodium and potassium salts, and thios derived from these. Acyl sulfides and dithioates such as methyl dithioacetate, ethyl dithioacetate and butyl ethanecarbodithioate are preferably used. Of these, particularly preferable are dithioesters such as methyl dithioacetate, ethyl dithioacetate and butyl ethanecarbodithioate.

(2) Carbon black.

The carbon black used in the present invention has a nitrogen adsorption specific surface area (N ₂ SA) of 75 m ² / g or more. When it is less than 75 m ² / g, heat generation is excellent, but strength and wear resistance are insufficient. Highly active carbon black is 1300
It means carbon black in which the amount of hydrogen (H ₂ amount) generated at 0 ° C. has the relation of the following formula with the most frequent mode diameter (Dst, mμ) of the aggregate distribution by the centrifugal sedimentation method.

H ₂ > 3.74-0.02 (Dst) Carbon black, which has a large amount of generated hydrogen, is in a state in which the formation of a carbon microcrystalline structure is insufficient, and the particle surface is rich in chemically active radicals. In general, generation amount of hydrogen (H ₂ amount), the reaction time in the process of generating carbon black, since it is known to be closely related to the reaction temperature and the like, generation amount of hydrogen (H ₂ amount) and carbon black coagulation The most frequent mode diameter (Dst) of the aggregate has a first-order correlation.
However, the carbon black used in the present invention is unique in that it has a high surface activity by setting the generated hydrogen amount (H ₂ amount) to be larger than the value calculated by the 3.74-0.02 (Dst) equation. ing.

Carbon black showing an amount of generated hydrogen (H ₂ amount) equal to or less than 3.74-0.02 (Dst) is not preferable because not only sufficient improvement of exothermic property cannot be obtained, but also abrasion resistance decreases. .

The amount of carbon black compounded is in the range of 20 to 150 parts by weight with respect to 100 parts by weight of the raw rubber. If the amount is less than 20 parts by weight, heat generation is improved, but the breaking strength and wear resistance are poor, which is not preferable. On the other hand, if it exceeds 150 parts by weight, the heat generation property is not improved.

Further, in the present invention, other compounding agents usually used in the rubber industry, for example, fillers, softening agents, plasticizers, antioxidants, vulcanizing agents, vulcanization accelerators and the like are compounded as necessary. It doesn't matter.

Hereinafter, examples and comparative examples will be shown, but the examples are not limited to these examples as long as the gist of the present invention is not exceeded.

Examples and Comparative Examples Each component was blended in the blending content (parts by weight) shown in Table 1 below, and the vulcanization accelerator, the raw rubber excluding sulfur and the blending agent were mixed for 5 minutes with a Banbury mixer of 1.7, and then A vulcanization accelerator and sulfur were kneaded with the mixture for 4 minutes with an 8-inch test kneading roll machine to obtain a rubber composition. These rubber compositions were press-vulcanized at 160 ° C. for 30 minutes to prepare target test pieces, various tests were carried out, and their physical properties were measured. The results are shown in Table 4 below. The properties of the used polymer and carbon black are shown in Tables 2 and 3, respectively.

Table 1 Polymer 100 parts by weight Carbon black 50 parts by weight Zinc oxide 3 parts by weight Stearic acid 1.5 parts by weight Aromatic oil 5 parts by weight Vulcanization accelerator ^{* 1} 1.0 parts by weight Sulfur yellow 1.75 parts by weight Note) * 1 N-cyclohexyl- 2-benzothiazyl sulfenamide.

Note) * 6 Seast 9 (manufactured by Tokai Carbon Co., Ltd.).

* 7 Measured by ASTM D 3037 (1984) Method C.

* 8 Measured according to JIS K 6221.

* 9 A disk centrifuge manufactured by Joyce-Rable was used and the measurement was carried out by the following method by the centrifugal sedimentation method.

That is, carbon black dried by JIS K 6221 (1982) 5 method and precisely weighed was added to a 20% aqueous solution of ethanol to make the carbon black concentration 0.005% by weight, and then sufficiently dispersed by ultrasonic waves to prepare a sample. . On the other hand, the rotation speed of the disc centrifuge was set to 8000 rpm, 10 ml of the spin liquid (distilled water) was added to this disc centrifuge, and then 0.5 ml of the buffer liquid (20% by volume ethanol aqueous solution) was injected. Then, add 0.5 ~
1.0 ml was added with a syringe, centrifugal sedimentation was started, an aggregate distribution curve was created by the photoprecipitation method, and the mode diameter of the aggregate was defined as the most frequent mode diameter Dst.

* 10 The amount of hydrogen generated at 1300 ° C under the following conditions for carbon black is expressed in mg converted to 1 g of carbon black. For the measurement, first, 10 mg of carbon black was pyrolyzed at high temperature (solid pyrolyzer).
Is thermally decomposed at 1300 ° C. for 120 seconds (20 seconds × 6 times), and the generated gas is introduced into a connected gas chromatography (Shimadzu GC-9A). At this time, nitrogen gas is introduced as a carrier gas at a constant flow rate (30 ml / min).

The gas chromatography analysis method uses the TCD method,
The conditions are as follows.

Column: Molecular sieve, 5A 3mφ × 3m Sample injection temperature: 100 ° C Column temperature: 40 ° C Carrier gas: Nitrogen gas, 30ml / min The amount of hydrogen generated was determined in advance by mixing a predetermined amount (1cc hydrogen gas with air). 1 and use 1cc of them)
The area-weight (mg) of the hydrogen amount was calculated in advance, and then it was calculated by the area method.

Note) <tanδ> Using a viscoelasticity spectrometer manufactured by Iwamoto Seisakusho, under the condition of strain rate of 10 ± 2% and frequency of 20Hz by extension deformation,
Measured at 0 ℃ and 60 ℃. The tan δ value at 0 ° C corresponds to the wet skid resistance value, and the tan δ value at 60 ° C corresponds to the exothermicity. The smaller the tan δ value at 60 ° C, the smaller the heat generation, and the fuel economy is exhibited when used for tires.

<Rebound resilience> Repulsion resilience is measured according to the method of JIS K 6301 at 60 ℃. The larger the value, the smaller the heat buildup.

<Abrasion resistance> Measured according to ASTM D2228 using a pico abrasion tester.
(Abrasion amount of Comparative Example 1) × 100 / (Abrasion amount of sample) is expressed as an index. Therefore, the larger the value, the better the wear resistance.

<Tensile properties> Measured according to JIS K 6301.

As is clear from the physical property table in Table 4, Examples 1 to 6 in which the modified polymer having a functional group introduced and activated carbon black are used in combination are clearly 60 compared to the corresponding Comparative Examples.
It can be seen that the tan δ at ° C or the impact resilience is improved and the low heat buildup is excellent.

For example, in Comparative Examples 8 to 10, Comparative Example 8 and Comparative Example 9
Comparing the results, the impact resilience of activated carbon black is improved by 0.3%. Further, from the comparison between Comparative Examples 8 and 10, it is found that the impact of the modified polymer is that the impact resilience is improved by 4.2%. Therefore, the effect of the combined use of the modified polymer and the activated carbon black is estimated to be at most 4.5%, but in Example 3 or 4 according to the present invention, an improvement of 8.1 to 8.3% was observed, and It is clearly shown that there is a combined effect of activated carbon black.

The above is summarized in FIG. 1 for the SBR polymer in Table 4. FIG. 1 shows the relationship between abrasion resistance and impact resilience in the SBR system. In the figure, the numbers in ○ and □ represent the numbers of Comparative Example and Example, respectively. From this figure, it is clear that the use of the rubber composition of the present invention significantly improves the heat generation property without impairing the wear resistance. Therefore, the rubber composition of the present invention can be suitably used, for example, as a rubber composition for a tread of a fuel-efficient tire.

〔The invention's effect〕

As described above, according to the present invention, by using a so-called modified polymer having a functional group introduced into the molecular chain (for example, benzophenone) and carbon black having a high surface activity (amount of generated hydrogen), heat generation is increased. A rubber composition having remarkably improved properties can be obtained. This rubber composition can be suitably used, for example, in a tread of a fuel efficient tire.

[Brief description of drawings]

FIG. 1 is a relational diagram between abrasion resistance and impact resilience in an SBR system.

Claims (1)

(57) [Claims] 1. A rubber-like polymer having an alkali metal and / or an alkaline earth metal added thereto, Organic compounds having a bond (in the formula, X represents an O or S atom), benzophenones having an amino group and / or a substituted amino group, thiobenzophenones having an amino group and / or a substituted amino group, a general formula (Wherein R represents hydrogen or an organic group, and n represents an integer of 1 to 4), a reaction having an aminobenzene derivative, an isocyanate compound, a monofunctional or bifunctional active tin compound, and a thioether group. Rubber 100 containing at least 30% by weight of a polymer obtained by reacting one or more compounds selected from a polymerizable compound, carbodiimides, carbon disulfide, a xanthogen compound and a dithioacid compound
With respect to parts by weight, the nitrogen adsorption specific surface area (N ₂ SA) is 75 m ² / g or more and the amount of hydrogen (H ₂ amount) generated at 1300 ° C is the most frequent mode diameter (Dst, m)) and 20 to 150 parts by weight of carbon black having the following formula. H _2> 3.74-0.02 (Dst)