JP2011148891A - Diene-based rubber composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a diene-based rubber composition which provides a vulcanizate excellent in processability, and excellent in elongation at break, an elastic modulus, and heat build-up, and therefore is effectively used as a molding material etc., of belt cushion of a pneumatic tire and/or that of an upper soft bead filler. <P>SOLUTION: The diene-based rubber composition is formed by compounding 100 pts.wt. of a diene-based rubber with 30-50 pts.wt. of carbon black with iodine adsorption of 70-100 g/kg and DBP absorption of (90-110)×10<SP>-5</SP>m<SP>3</SP>/kg, wherein the diene-based rubber is composed of (A) 95-99 wt.% of a diene-based rubber and (B) 5-1 wt.% of hydrogen bond-forming thermoplastic elastomer of which the main chain is composed of a diene-based rubber, which has a carbonyl-containing group and a nitrogen-containing heterocycle in the molecule, and of which the weight-average molecular weight Mw is 50,000 or more. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a diene rubber composition. More specifically, the present invention relates to a diene rubber composition suitably used as a molding material for a pneumatic tire belt cushion, an upper soft bead filler, and the like.

  Since the belt cushion and the upper soft bead filler of a pneumatic tire are arranged inside the tire and easily store heat, it is an important characteristic that they have low exothermic properties. In addition, if the elastic modulus is small, deformation during driving increases and fatigue deterioration easily progresses, and the movement of each adjacent part increases, resulting in deterioration of tire heat generation and breakdown phenomena such as separation. Therefore, sufficient consideration should be given to the elastic modulus.

  Thus, in the belt cushion and the upper soft bead filler, it can be said that exothermic properties, elastic modulus, and elongation at break are important physical properties. Generally, silica is blended in order to improve the heat build-up, but in this case, the viscosity increases and the factory processability deteriorates. In order to obtain high elongation at break, it is conceivable to reduce the amount of carbon black to be blended or increase the specific surface area, but this leads to a decrease in the elastic modulus.

  Patent Documents 1 and 2 include one or two or more types of monomers containing a polar group-containing monomer such as a carboxyl group, a carbonyl group, an oxycarbonyl group, and a nitrogen-containing heterocyclic group in natural rubber latex. By forming a tread undercushion and / or a belt undercushion of a pneumatic tire using a rubber composition containing 10% by weight or more of a grafted modified natural rubber, low heat buildup and high fracture resistance are achieved. It is stated that a pneumatic tire is provided.

Examples of the carboxyl group-containing monomer include unsaturated carboxylic acids such as (meth) acrylic acid, maleic acid, fumaric acid, itaconic acid, tetraconic acid, cinnamic acid, and the rubber composition contains DBP absorption. Carbon black having an amount of 80 × 10 ^-5 m ³ / kg or more, for example, SAF, ISAF, HAF, FEF, GPF carbon black is said to be compounded.In that example, N330 (HAF) carbon black is a modified natural rubber 100 It is used at a rate of 10 to 55 parts by weight per part by weight, and low tan δ values are also shown.

  However, the modified natural rubber used here is obtained by graft polymerization of a polar group-containing monomer to natural rubber latex and does not have hydrogen bonding properties. In some cases, the tread undercushion and / or the belt undercushion of the tires in which no consideration is given to the elastic modulus.

JP 2006-151259 A JP 2006-151163 A Japanese Patent No. 3,998,690 Japanese Patent No. 4,011,057 Japanese Patent No. 4,037,016 EP 0 933 381 A1

  The object of the present invention is to provide a vulcanizate having excellent workability, excellent elongation at break, elastic modulus and exothermicity, and therefore, as a molding material for a pneumatic tire belt cushion and / or upper soft bead filler, etc. It is to provide a diene rubber composition that is effectively used.

The object of the present invention is to provide a weight average molecular weight Mw having (A) 95 to 99% by weight of a diene rubber and (B) a main chain comprising a diene rubber and having a carbonyl-containing group and a nitrogen-containing heterocycle in the molecule. Per 100 parts by weight of diene rubber consisting of 5 to 1% by weight of hydrogen-bonding thermoplastic elastomer with a weight of 50,000 or less, iodine adsorption is 70 to 100 g / kg, and DBP absorption is 90 to 110 × 10 ⁻⁵ m ³ / This is achieved by a diene rubber composition comprising 30-50 parts by weight of carbon black. As such a hydrogen bondable thermoplastic elastomer, a polymer main chain composed of a diene rubber is preferably reacted sequentially with a carbonyl group-containing unsaturated compound and a nitrogen-containing heterocyclic compound substituted with a functional group capable of reacting with the carbonyl group. The diene polymer obtained by making it use is used.

  The diene rubber composition according to the present invention is excellent in processability, and can give a vulcanizate excellent in elongation at break, elastic modulus and heat build-up, so that it is formed into a pneumatic tire belt cushion and an upper soft bead filler. It can be used effectively as a material.

  As the diene rubber, any diene rubber used for tire production can be used, preferably natural rubber (NR), isoprene rubber (IR), butadiene rubber (BR), 1,2-butadiene rubber, styrene. Butadiene rubber (SBR), acrylonitrile-butadiene rubber (NBR), chloroprene rubber (CR), and hydrogenated products thereof are used. As SBR, either emulsion polymerization SBR (E-SBR) or solution polymerization SBR (S-SBR) can be used.

  The hydrogen-bonding thermoplastic elastomer added to these diene rubbers has a main chain made of a diene rubber, has a carbonyl-containing group and a nitrogen-containing heterocyclic ring in the molecule, and has a weight average molecular weight Mw (by GPC method). Measurement: polystyrene conversion) of 50,000 or less, preferably 10,000 to 40,000 is used. Such hydrogen-bonding thermoplastic elastomers are described in Patent Documents 3 to 5 and the like that describe patent inventions related to the applicant's application.

式中、Aは含窒素複素環であり、Bは結合基であって、単結合、酸素原子、イオウ原子、アミノ基NR′および酸素原子、イオウ原子またはアミノ基NR′を含んでもよい有機基からなる群から選ばれる少なくとも1種であり、R′は水素原子または炭素数1〜10のアルキル基である。 Examples of the side chain containing a nitrogen-containing heterocyclic ring and a carbonyl group in one side chain include those containing a structure represented by the following formula (1).

In the formula, A is a nitrogen-containing heterocyclic ring, B is a linking group, and a single bond, an oxygen atom, a sulfur atom, an amino group NR ′ and an organic group which may contain an oxygen atom, a sulfur atom or an amino group NR ′ And R ′ is a hydrogen atom or an alkyl group having 1 to 10 carbon atoms.

  From the viewpoint of excellent compression set and mechanical strength, the polymer has a side chain in which at least part or all of the side chains contain a carbonyl group and a nitrogen-containing heterocyclic ring in one side chain ( It preferably has a structure represented by 1).

  The nitrogen-containing heterocycle A is not particularly limited as long as it contains a nitrogen atom in the heterocycle, and can have a heteroatom other than the nitrogen atom, for example, a sulfur atom, an oxygen atom, a phosphorus atom, etc. in the heterocycle. .

  The nitrogen-containing heterocyclic ring A may have a substituent. Examples of the substituent include alkyl groups such as methyl group, ethyl group, (iso) propyl group, and hexyl group; alkoxy groups such as methoxy group, ethoxy group, and (iso) propoxy group; fluorine atom, chlorine atom, bromine atom or A group consisting of a halogen atom which is an iodine atom; a cyano group; an amino group; an aromatic hydrocarbon group; an ester group; an ether group; an acyl group; The substituents can be used alone or in combination of two or more, and the number thereof is not limited.

  The nitrogen-containing heterocyclic ring A can have aromaticity. When the nitrogen-containing heterocyclic ring A has aromaticity, it is preferable because the crosslinked rubber composition obtained by crosslinking the composition by hydrogen bonding or the like is excellent in tensile strength, mechanical strength, and the like.

  The nitrogen-containing heterocycle is preferably a 5-membered ring or a 6-membered ring. Examples of such nitrogen-containing heterocycle include pyrrolidine, pyrrolidone, oxindole (2-oxindole), indoxyl (3-oxindole), dioxindole, isatin, indolyl, phthalimidine, β-isoindigo, monoporphyrin, Diporphyrin, triporphyrin, azaporphyrin, phthalocyanine, hemoglobin, uroporphyrin, chlorophyll, phyloerythrin, imidazole, pyrazole, triazole, tetrazole, benzimidazole, benzopyrazole, benzotriazole, imidazoline, imidazolone, imidazolidone, hydantoin, pyrazoline, pyrazolone , Pyrazolidone, indazole, pyridoindole, purine, cinnoline, pyrrole, pyrroline, indole, indoline, oxy Luindole, carbazole, phenothiazine, indolenine, isoindole, oxazole, thiazole, isoxazole, isothiazole, oxadiazole, thiadiazole, oxatriazole, thiatriazole, phenanthroline, oxazine, benzoxazine, phthalazine, pteridine, pyrazine, phenazine, Tetrazine, benzoxazole, benzisoxazole, anthranyl, benzothiazole, benzofurazan, pyridine, quinoline, isoquinoline, acridine, phenanthridine, anthrazolin, naphthyridine, thiazine, pyridazine, pyrimidine, quinazoline, quinoxaline, triazine, histidine, triazolidine, melamine, Adenine, guanine, thymine, cytosine, isocyanuric acid and These derivatives, and the like. In addition, the nitrogen-containing heterocycle may have, for example, the same substituent as described above, or may have a hydrogen atom added or eliminated.

  The bonding position of the nitrogen-containing heterocycle will be described. For convenience, the nitrogen-containing heterocycle is referred to as “nitrogen-containing n-membered ring compound (n ≧ 3)”. The binding positions described below ("1 to n positions") are based on the IUPAC nomenclature. For example, in the case of a compound having three nitrogen atoms having an unshared electron pair, the bonding position is determined by the order based on the IUPAC nomenclature. Specifically, the bonding positions are indicated on the 5-membered, 6-membered and condensed nitrogen-containing heterocycles exemplified below. In the polymer, when the nitrogen-containing heterocyclic ring is bonded to the elastomer as the main chain directly or via an organic group, the bonding position of the nitrogen-containing n-membered ring compound is not particularly limited, and any bonding position (position 1 to position n) ) Preferably, it is the 1-position or 3-position to n-position.

  When the nitrogen-containing n-membered ring compound contains one nitrogen atom (for example, a pyridine ring), the chelate is easily formed in the molecule, and the physical properties such as the tensile strength when the composition is used are excellent. The (n-1) position is preferred.

  From the viewpoint of excellent compression set and mechanical properties, the nitrogen-containing five-membered ring includes the following group of compounds, a triazole derivative represented by the following formula (2), and an imidazole derivative represented by the following formula (3). preferable.

  In the formula, the substituent X is not particularly limited as long as it is an alkyl group having 1 to 30 carbon atoms, an aralkyl group having 7 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms. Examples of the substituent X include a linear alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, an octyl group, a dodecyl group, and a stearyl group; an isopropyl group, an isobutyl group, an s-butyl group, t-butyl group, isopentyl group, neopentyl group, t-pentyl group, 1-methylbutyl group, 1-methylheptyl group, 2-ethylhexyl group and other branched alkyl groups; benzyl group, phenethyl group and other aralkyl groups; phenyl And aryl groups such as a tolyl group (o-, m-, p-), a dimethylphenyl group, and a mesityl group.

  Examples of the nitrogen-containing 6-membered ring include the following group of compounds and isocyanuric acid (for example, a trimer of an isocyanate group-containing compound). The nitrogen-containing six-membered ring may have the above-described substituent, or may have a hydrogen atom added or eliminated.

  Further, the nitrogen-containing heterocycle may be a condensed ring having a nitrogen-containing heterocycle, and examples thereof include those condensed with a benzene ring, those condensed with nitrogen-containing heterocycles, and the like. Specific examples include the following group of condensed rings. The condensed ring may have the above-described substituent, or may have a hydrogen atom added or eliminated.

式中、R¹、R²、R³は、それぞれ独立に、水素原子；メチル基、エチル基等のアルキル基；メトキシ基、エトキシ基等のアルコキシル基；ヒドロキシメチル基、ヒドロキシエチル基等のヒドロキシル基含有基；塩素原子、臭素原子等のハロゲン原子；ヒドロキシル基；シアノ基；アミノ基；エステル基；エーテル基である。R¹、R²、R³は、それぞれ異なっていてもよく、同一でもよい。イソシアヌル酸としては、例えば1,3,5-トリス(2-ヒドロキシエチル)イソシアヌル酸が挙げられる。 Examples of isocyanuric acid include those represented by the following formula.

In the formula, R ¹ , R ² and R ³ are each independently a hydrogen atom; an alkyl group such as a methyl group or an ethyl group; an alkoxyl group such as a methoxy group or an ethoxy group; a hydroxyl group such as a hydroxymethyl group or a hydroxyethyl group A group-containing group; a halogen atom such as a chlorine atom or a bromine atom; a hydroxyl group; a cyano group; an amino group; an ester group; R ¹ , R ² and R ³ may be different or the same. Examples of isocyanuric acid include 1,3,5-tris (2-hydroxyethyl) isocyanuric acid.

  Among the nitrogen-containing heterocycles, the obtained crosslinked rubber composition is excellent in compression set resistance, mechanical strength and hardness, from the viewpoint of triazole ring, thiadiazole ring, pyridine ring, thiazole ring, imidazole ring, hydantoin ring, Isocyanuric acid is preferred. The nitrogen-containing heterocyclic ring-containing groups can be used alone or in combination of two or more.

The bonding group B is at least one selected from the group consisting of a single bond, an oxygen atom, a sulfur atom, an amino group NR ′ and an organic group which may contain an oxygen atom, a sulfur atom or an amino group NR ′, and R ′ is a hydrogen atom. An atom or an alkyl group having 1 to 10 carbon atoms is preferred. This organic group is a hydrocarbon group that can contain an oxygen atom, a sulfur atom or an amino group NR ′, and examples of the hydrocarbon group include an alkylene group having 1 to 20 carbon atoms (for example, —CH ₂ CH ₂ —). Is mentioned. In addition, when the organic group has at least one selected from the group consisting of an oxygen atom, a sulfur atom and an amino group NR ′ at the terminal or side chain, for example, an alkylene ether group having 1 to 20 carbon atoms (an alkyleneoxy group, for example, _{-O-CH 2 CH 2 -)} , alkyleneamino group (e.g. _{-NH-CH 2 CH 2 -)} , alkylene thioether group (alkylene thio group, for example, -S-CH ₂ CH ₂ -) and the like. R ′ in the amino group NR ′ (alkyl group having 1 to 10 carbon atoms) is methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group And includes isomers.

As described above, the bonding group B which is at least one selected from the group consisting of a single bond, an oxygen atom, a sulfur atom, an amino group NR ′ and an organic group which may contain an oxygen atom, a sulfur atom or an amino group NR ′ is a mechanical group. From the viewpoint of excellent strength, it is preferable to form an ester group, an amide group, an imide group, a thioester group or the like adjacent to the carbonyl group in the formula (1). Among them, the linking group B may contain an oxygen atom, a sulfur atom, an amino group NR ′, an oxygen atom, a sulfur atom or an amino group NR ′ that forms a conjugated system adjacent to the carbonyl group in the formula (1). It is preferably an alkylene ether group having 1 to 20 carbon atoms, an alkyleneamino group or an alkylenethioether group having at least one selected from the group consisting of organic groups, and an amino group (NH), an alkyleneamino group (-NH _{-CH 2 -, - NH-CH} 2 CH 2 -, - NH-CH 2 CH 2 CH 2 -), alkylene ether group _{(-O-CH 2 -, -} O-CH 2 CH 2 -, - O-CH ₂ CH ₂ CH _2- ) is more preferable. Each of the bonding groups B can be used alone or in combination of two or more.

  Examples of the side chain containing the structure represented by the formula (1) include structures represented by the following formulas (4) and (5).

式中、Aは含窒素複素環であり、BおよびDは、それぞれ独立に、単結合、酸素原子、イオウ原子、アミノ基NR′および酸素原子、イオウ原子またはアミノ基NR′を含んでもよい有機基からなる群から選ばれる少なくとも一種であり、R′は水素原子または炭素数1〜10のアルキル基であり、α-位またはβ-位において直接または有機基を介して前記ポリマーの主鎖に結合する。

In the formula, A is a nitrogen-containing heterocyclic ring, and B and D are each independently an organic group that may contain a single bond, an oxygen atom, a sulfur atom, an amino group NR ′, and an oxygen atom, a sulfur atom, or an amino group NR ′. At least one selected from the group consisting of a group, R ′ is a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and is directly or via an organic group at the α-position or β-position to the main chain of the polymer. Join.

  Specifically, the nitrogen-containing heterocycle A is basically the same as the nitrogen-containing heterocycle A of the formula (1). The linking groups B and D are basically the same as the linking group B in the formula (1). However, the substituent D in the formula (5) is a C 1-20 alkylene group which may contain a single bond, an oxygen atom, a sulfur atom or an amino group NR ′ from the viewpoint of excellent compression set and mechanical strength. Alternatively, an aralkylene group in which an oxygen atom, a sulfur atom, or an amino group NR ′ forms a conjugated system with an imide nitrogen is preferable, and a single bond is more preferable. The substituents D can be used alone or in combination of two or more.

  As the hydrogen-bonding thermoplastic elastomer, a polymer main chain composed of a diene rubber is preferably reacted successively with a carbonyl group-containing unsaturated compound and a nitrogen-containing heterocyclic compound substituted with a functional group capable of reacting with the carbonyl group. The diene polymer obtained in this way is used.

  Diene rubber molecules of hydrogen bondable thermoplastic elastomer whose main chain consists of diene rubber molecules include natural rubber (NR), isoprene rubber (IR), butadiene rubber (BR), chloroprene rubber (CR), nitrile rubber ( NBR), styrene butadiene rubber (SBR) or the like is used, and isoprene rubber (IR) is preferably used.

  Examples of the carbonyl group-containing unsaturated compound that undergoes an addition reaction to the polymer main chain of these diene rubber molecules include maleic anhydride and maleic acid, and maleic anhydride is preferably used. The modification rate of maleic anhydride is generally set to about 0.1 to 10% by weight based on the weight of the polymer molecule to be modified.

  The addition reaction of maleic anhydride to the polymer main chain is preferably carried out by an ene reaction. As described in Patent Document 6, maleic anhydride is ring-opened in the usual addition reaction, and most of the maleic anhydride is added as maleic acid. However, according to the ene reaction, maleic anhydride is almost all of its acid anhydride structure. It is added while holding

  As such a maleic anhydride-added diene rubber, a commercially available product can be used as it is. Examples of maleic anhydride-modified liquid polyisoprene rubber include Kuraray product LIR-410A.

  The maleic anhydride group thus added includes a nitrogen-containing heterocyclic compound in which the nitrogen-containing heterocyclic ring is a 5-membered ring or a 6-membered ring and is substituted with a functional group capable of reacting with maleic acid, for example. 4H-3-amino-1,2,4-triazole, 4-aminopyridine and the like in which the substituted functional group is an amino group, 4-hydroxypyridine in which the substituted functional group is a hydroxyl group, 4- The addition reaction is further carried out by heating at about 120 to 200 ° C. using a small excess of methylolpyridine and the like.

  The reaction of the nitrogen-containing heterocyclic compound substituted with a functional group having reactivity with maleic anhydride or the like is carried out under reaction conditions such as kneading at about 170 to 200 ° C. for 30 minutes in the absence of a reaction solvent. However, it can also be carried out by kneading for about 1 to 3 hours at room temperature using a reaction solvent such as chloroform.

  The functional group of the nitrogen-containing heterocyclic compound that reacts with maleic anhydride or the like is used in an equivalent amount or more, and as shown in the following reaction formula, first, an amic bond in which an amide bond is formed with one carboxyl group. Although an acid is formed, an imide bond is formed as the dehydration reaction further proceeds.

  Here, as a thermoplastic elastomer, an addition reaction of maleic anhydride to a diene rubber and further reaction with a functional group-substituted nitrogen-containing heterocyclic compound is a carbonyl group derived from a carbonyl group-containing unsaturated compound, and Self-crosslinking is possible by forming a hydrogen bond consisting of a donor-H-acceptor as shown by OH… O, NH… O, OH… N, NH… N with the reacted nitrogen-containing heterocyclic compound. In addition, it dissociates during heating (120 ° C.), and forms hydrogen bonds again at around room temperature.

  A hydrogen-bonding thermoplastic elastomer obtained by sequentially reacting a carbonyl group-containing unsaturated compound and a nitrogen-containing heterocyclic compound substituted with a functional group capable of reacting with the polymer main chain obtained by such a series of reactions, The diene rubber is used in a ratio of 5 to 1% by weight with respect to 95 to 99% by weight. When used in a smaller proportion, no significant improvement is observed in various properties, while when used in a proportion higher than this, the exothermic property is improved, but the elongation at break is significantly reduced.

A diene rubber consisting of 95 to 99% by weight of a diene rubber and 5 to 1% by weight of a hydrogen-bonding thermoplastic elastomer has an iodine adsorption of 70 to 100 g / kg and a DBP absorption of 100 parts by weight. 90 to 110 × 10 ⁻⁵ m ³ / kg of carbon black is used in an amount of 30 to 50 parts by weight, preferably 35 to 45 parts by weight.

  When carbon black with iodine adsorption and DBP absorption is larger than this, viscosity, elastic modulus and exothermicity will decrease, and even when an appropriate amount of hydrogen bonding thermoplastic elastomer is used, viscosity and elastic modulus Inevitable decrease in Further, even when carbon black having a prescribed property is used, if it is used more than the prescribed amount, the elastic modulus is increased, but the viscosity, elongation at break, exothermicity is reduced, Even when an appropriate amount of a hydrogen bonding thermoplastic elastomer is used, the viscosity and elongation at break are unavoidable.

  In the rubber composition containing the above components as essential components, sulfur and thiazole (MBT, MBTS, ZnMBT, etc.), sulfenamide (CBS, DCBS, BBS, etc.), guanidine ( DPG, DOTG, OTBG, etc.), thiuram (TMTD, TMTM, TBzTD, TETD, TBTD, etc.), dithiocarbamate (ZTC, NaBDC, etc.), xanthate (ZnBX, etc.), etc. One or more types are blended and used. Furthermore, other compounding agents generally used as rubber compounding agents, such as reinforcing agents or fillers such as talc, clay, graphite, calcium silicate, processing aids such as stearic acid, zinc oxide, softeners, A plasticizer, an antiaging agent, and the like are appropriately blended and used as necessary.

  Preparation of the composition is carried out by kneading by a general method using a kneader such as a kneader, a Banbury mixer or a mixer and an open roll, and the obtained composition is molded into a predetermined shape, The rubber is vulcanized at a vulcanization temperature according to the type of diene rubber, vulcanizing agent and vulcanization accelerator used, and the blending ratio thereof, to form a belt cushion for a pneumatic tire, an upper soft bead filler, and the like.

  Next, the present invention will be described with reference to examples.

Reference Example Maleic anhydride-modified liquid isoprene rubber (Kuraray product LIR-410A; Mw 25,000, maleic anhydride modification rate 3.9% by weight) 200.0 g (79.6 mmol in terms of maleic anhydride skeleton) was mixed with 4H-3-amino-1, 6.97 g (82.9 mmol) of 2,4-triazole was added and stirred at 160 ° C. for 3 hours. After confirming that the solution was uniform, the solution was allowed to stand overnight to obtain 202.8 g of a gel-like hydrogen-bonding thermoplastic elastomer (yield 98%).

または

The gel-like hydrogen-bonding thermoplastic elastomer that is the reaction product is considered to have an amic acid bond [I], an imide bond [II], or both, and the main product is [II 〕it is conceivable that.

Or

Standard example Natural rubber (RSS # 3) 100 parts by weight
HAF carbon black (Cabot Japan product show black N330, 40 〃
(I ₂ adsorption amount 75g / kg, DBP absorption amount 81 × 10 ^-5 m ³ / kg)
Anti-aging agent (Sumitomo Chemical Antigen RD-G) 2
Stearic acid (NOF product beads stearic acid) 2 〃
Zinc Hana (Zinc Oxide Industrial Products, 3 types of zinc oxide) 3
Sulfur (Akzo Nobel product Christex HS OT20) 1 〃
Vulcanization accelerator (Ouchi Emerging Chemical Industry Noxeller DM) 1 〃
The above components were kneaded using a 1.8 L hermetic mixer, and the kneaded product was press vulcanized at 150 ° C. for 30 minutes.

The following items were measured for the diene rubber composition as a kneaded product and the obtained vulcanizate. All measurement results are indicated by an index with a standard example of 100.
Viscosity: JIS K6300 compliant, measured at 100 ° C using a large rotor
(The smaller the index, the higher the viscosity and the worse the workability)
Elongation at break: JIS K6251 compliant, measured at room temperature
(The larger the index, the greater the elongation at break and the better)
Elastic modulus: JIS K6251 compliant
(The larger the index, the higher the elastic modulus)
Exothermic: JIS K6394 compliant, initial strain 10%, amplitude ± 2%, frequency 20Hz, to 60 ° C
Tan δ measurement
(The higher the index, the less heat is generated and the better the low heat generation)

Comparative Example 1
In the standard example, the amount of HAF carbon black [HAF CB] was changed to 55 parts by weight.

Comparative Example 2
In the standard example, instead of HAF carbon black, the same amount (40 parts by weight) of ISAF carbon black (ISAF CB) (Cabot Japan product show black N234, I ₂ adsorption amount 123 g / kg, DBP absorption amount 118 × 10 ^-5 m ³ / kg) was used.

Comparative Example 3
In the standard example, the amount of natural rubber [NR] was changed to 99.5 parts by weight, and 0.5 parts by weight of the hydrogen bonding thermoplastic elastomer [TPE] obtained in the above reference example was used.

Comparative Example 4
In the standard example, the amount of NR was changed to 90 parts by weight, and 10 parts by weight of TPE was used.

Comparative Example 5
In Comparative Example 1, the amount of NR was changed to 97 parts by weight, and 3 parts by weight of TPE was used.

Comparative Example 6
In Comparative Example 2, the amount of NR was changed to 97 parts by weight, and 3 parts by weight of TPE was used.

Example 1
In the standard example, the amount of NR was changed to 99 parts by weight, and 1 part by weight of TPE was used.

Example 2
In the standard example, the amount of NR was changed to 97 parts by weight, and 3 parts by weight of TPE was used.

Example 3
In the standard example, the amount of NR was changed to 95 parts by weight, and 5 parts by weight of TPE was used.

Example 4
In Example 2, the amount of HAF CB was changed to 30 parts by weight.

The measurement results obtained in the above standard examples, comparative examples and examples are shown in the following table together with the blending amount (parts by weight) of diene rubber (NR + TPE) and carbon black.
table
Compounding component measurement results
Example NR TPE HAF ISAF Viscosity at break elongation modulus exothermic property
Standard example 100 40 100 100 100 100
Comparative Example 1 100 55 95 94 105 93
〃 2 100 40 94 100 95 92
〃 3 99.5 0.5 40 99 99 100 101
４ 4 90 10 40 97 90 100 116
５ 5 97 3 55 94 92 105 100
６ 6 97 3 40 93 98 95 99
Example 1 99 1 40 99 99 100 105
〃 2 97 3 40 99 98 100 107
３ 3 95 5 40 98 96 100 108
４ 4 97 3 30 102 102 96 111

From the above results, the following can be said.
(1) Each example has substantially the same viscosity, elongation at break and elastic modulus as compared with the standard example, and has improved heat generation.
(2) When ISAF CB is used, the viscosity increases, the elastic modulus decreases, and the exothermic property deteriorates (Comparative Example 2). Even when an appropriate amount of TPE is used, the viscosity increases and the elastic modulus decreases. A decrease is inevitable (Comparative Example 6).
(3) If HAF CB is used in an amount greater than the specified amount, the elastic modulus increases, but the viscosity increases, the elongation at break decreases, and the exothermicity deteriorates (Comparative Example 1), TPE. Even when an appropriate amount of is used, an increase in viscosity and a decrease in elongation at break are inevitable (Comparative Example 5).
(4) When the amount of TPE is less than the specified amount, no particular improvement is observed in various properties (Comparative Example 3), and when it is too much, the exothermic property is greatly improved, but the elongation at break is significantly reduced. (Comparative Example 4).

Claims (5)

(A) 95 to 99% by weight of diene rubber and (B) hydrogen bondability with a main chain made of diene rubber and having a carbonyl-containing group and a nitrogen-containing heterocycle in the molecule, and a weight average molecular weight Mw of 50,000 or less Per 100 parts by weight of diene rubber consisting of 5 to 1% by weight of thermoplastic elastomer, 30 to 30 carbon black with iodine adsorption of 70 to 100 g / kg and DBP absorption of 90 to 110 x 10 ^-5 m ³ / kg A diene rubber composition comprising 50 parts by weight.   (B) Component Hydrogen-bonding thermoplastic elastomer reacts sequentially with polymer main chain made of diene rubber with carbonyl group-containing unsaturated compound and nitrogen-containing heterocyclic compound substituted with functional group capable of reacting with this carbonyl group The diene rubber composition according to claim 1, wherein the diene rubber composition is a diene polymer obtained.   The diene rubber composition according to claim 2, wherein the nitrogen-containing heterocyclic compound substituted with a functional group capable of reacting with a carbonyl group is an amino group-substituted or hydroxyl group-substituted nitrogen-containing heterocyclic compound.   The diene rubber composition according to claim 1, 2 or 3, which is used as a molding material for a belt cushion of a pneumatic tire and / or an upper soft bead filler.   A pneumatic tire having a belt cushion and / or an upper soft bead filler molded and vulcanized from the diene rubber composition according to claim 4.