JP5855960B2 - Method for producing rubber composition for tire - Google Patents

Description

  The present invention relates to a method for producing a rubber composition for tires having a sufficiently low exothermic property without impairing processability.

In recent years, there has been an increasing demand for fuel efficiency reduction of automobiles in connection with the global movement of regulation of carbon dioxide emissions due to increasing interest in environmental problems. In order to meet such demands, reduction of rolling resistance is also demanded for tire performance. Conventionally, as a method of reducing the rolling resistance of the tire, a method of optimizing the tire structure has been studied, but a rubber composition having lower heat generation is currently used as a rubber composition applied to a tire tread. It is the most common method.
As a method for obtaining such a rubber composition for tires having a low exothermic property, a method using an inorganic filler such as silica as a filler is known.

  For example, a rubber composition that can be used in the manufacture of tires, comprising at least: (i) a diene elastomer, (ii) a silica-based or alumina-based filler as a reinforcing filler, preferably an inorganic filler that is highly dispersible silica, iii) A rubber composition based on polysulfated alkoxysilane (PSAS) as a coupling agent and (iv) 1,2-dihydropyridine (1,2-DHP) and (v) a guanidine derivative (see, for example, Patent Document 1) And a rubber composition for tires that improves silica dispersibility by mixing silica-containing rubber composition in a state in which temperature control at a relatively high temperature is easy, and a method for producing the rubber composition. In producing a rubber composition by mixing 10 to 150 parts by weight of silica with a hermetic mixer with respect to parts by weight, 1 to 20 parts by weight of a pulling agent and 0.5 to 5 parts by weight of a compound containing at least one kind of guanidine group, sulfenamide group and benzothiazyl group are mixed in the same mixing step as the mixing of the diene rubber and silica. A known method for producing a tire rubber composition and a tire rubber composition produced by this method (see, for example, Patent Document 2) are known.

  However, in these inventions, when the amount of inorganic filler such as silica is increased as a filler for the purpose of improving low heat build-up, the workability such as extrusion workability deteriorates as the viscosity increases, and is still sufficient. There is a problem in that a rubber composition for tires having a low heat build-up property cannot be obtained.

JP 2003-523472 A (Claims, Examples, etc.) JP 2007-154130 A (Claims, Examples, etc.)

  The present invention has been made in view of the above-described conventional problems, and is intended to solve this problem. There is no increase in viscosity, the workability such as extrusion workability is improved, and the rubber composition for tires having sufficiently low heat generation properties is provided. An object is to provide a manufacturing method.

  As a result of intensive studies on the above-mentioned conventional problems, the present inventor has found that a filler (B) containing an inorganic filler with respect to at least one rubber component (A) selected from natural rubber and synthetic diene rubber. ), A silane coupling agent (C), a specific alkanolamide compound (D), and at least one vulcanization accelerator selected from thiurams, dithiocarbamates, thioureas, xanthates and guanidines, Alternatively, a method for producing a rubber composition for a tire comprising a secondary amine or a salt compound (E) formed from a secondary amine and a weak acid component, the rubber composition being kneaded in a plurality of stages, In the first stage of kneading, it is found that a specific method for producing the rubber composition for a tire can be obtained by kneading specific components in the above (A) to (E). Invention is that the has been completed.

That is, the present invention resides in the following (1) to (6).
(1) For a rubber component (A) composed of at least one selected from natural rubber and synthetic diene rubber, a filler (B) containing an inorganic filler, a silane coupling agent (C), and the following formula An alkanolamide compound (D) represented by (I) and at least one vulcanization accelerator selected from thiurams, dithiocarbamates, thioureas, xanthates and guanidines, or a secondary amine, or A method for producing a rubber composition for a tire comprising a salt compound (E) formed from a secondary amine and a weak acid component,
The rubber composition is kneaded in a plurality of stages, and in the first stage of kneading, all or part of the rubber component (A), the filler (B), and all or one of the silane coupling agent (C). Part, alkanolamide compound (D) and the vulcanization accelerator, or secondary amine, or a salt compound (E) formed from a secondary amine and a weak acid component is kneaded. A method for producing the composition.
[In the above formula (I), R ₁ represents an alkyl group or alkenyl group having 1 to 24 carbon atoms, and the alkyl group and alkenyl group may be linear, branched or cyclic, , R ₂ is a hydroxyalkyl group or a hydroxyalkyl group having an oxyalkylene unit, and R ₃ is a hydrogen atom, a hydroxyalkyl group or a hydroxyalkyl group having an oxyalkylene unit. ]
(2) The method for producing a rubber composition for a tire according to the above (1), wherein the maximum temperature of the rubber composition in the rubber composition in the first stage of the kneading is 120 to 190 ° C.
(3) The filler (B) contains silica and carbon black, and the amount of the filler (B) is 10 to 200 parts by mass with respect to 100 parts by mass of the rubber component (A) ( The manufacturing method of the rubber composition for tires as described in 1) or (2).
(4) The manufacturing method of the rubber composition for tires as described in said (3) whose content of the said silica is 5-90 mass% in all the fillers (B).
(5) The method for producing a rubber composition for a tire according to any one of (1) to (4), wherein zinc oxide is added after the second stage of kneading.
(6) The manufacturing method of the rubber composition for tires as described in said (5) whose compounding quantity of a zinc oxide is 0.1-5 mass parts with respect to 100 mass parts of rubber components (A).

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the rubber composition for tires which does not raise a viscosity, improves processability, such as extrusion workability | operativity, and has sufficient low heat generation property is provided.

The present invention is described in detail below.
The method for producing a rubber composition for a tire according to the present invention includes a filler (B) containing an inorganic filler and a silane with respect to a rubber component (A) composed of at least one selected from natural rubber and synthetic diene rubber. At least one vulcanization selected from a coupling agent (C), an alkanolamide compound (D) represented by the following formula (I), thiurams, dithiocarbamates, thioureas, xanthates and guanidines A method for producing a tire rubber composition comprising an accelerator, or a secondary amine, or a salt compound (E) formed from a secondary amine and a weak acid component,
The rubber composition is kneaded in a plurality of stages, and in the first stage of kneading, all or part of the rubber component (A), the filler (B), and all or one of the silane coupling agent (C). Part, an alkanolamide compound (D) and the vulcanization accelerator, or a secondary amine, or a salt compound (E) formed from a secondary amine and a weak acid component is kneaded. .
[In the above formula (I), R ₁ represents an alkyl group or alkenyl group having 1 to 24 carbon atoms, and the alkyl group and alkenyl group may be linear, branched or cyclic, , R ₂ is a hydroxyalkyl group or a hydroxyalkyl group having an oxyalkylene unit, and R ₃ is a hydrogen atom, a hydroxyalkyl group or a hydroxyalkyl group having an oxyalkylene unit. ]

The kneading step of the tire rubber composition in the present invention includes a vulcanization accelerator, a secondary amine, or other vulcanizing agent excluding a salt compound (E) formed from the secondary amine and a weak acid component, etc. Including at least two stages of a kneading-free first stage and a final stage of kneading containing a vulcanizing agent, etc., if necessary, a vulcanization accelerator, a secondary amine, or a secondary An intermediate stage of kneading that does not contain other vulcanizing agents other than the salt compound (E) formed from the amine and the weak acid component may be included. Here, vulcanizing agents and the like refer to vulcanizing agents and vulcanization accelerators.
The first stage of kneading in the present invention refers to the first stage of kneading the rubber component (A), the filler (B), the silane coupling agent (C), and the alkanolamide compound (D). The step of kneading the rubber component (A) and a filler other than the filler (B) in the step of the above or the case of preliminarily kneading only the rubber component (A) is not included.

[Rubber component (A)]
As the synthetic diene rubber of the rubber component (A) used in the production method of the present invention, styrene-butadiene copolymer rubber (SBR), polybutadiene rubber (BR), polyisoprene rubber (IR), butyl rubber (IIR), Ethylene-propylene-diene terpolymer rubber (EPDM) or the like can be used, and natural rubber and synthetic diene rubber may be used singly or as a blend of two or more.

[Filler containing inorganic filler (B)]
As the inorganic filler used in the production method of the present invention, silica and an inorganic compound represented by the following formula (III) can be used.
nM · xSiOy · zH ₂ O (III)
[In the above formula (III), M is a metal selected from the group consisting of aluminum, magnesium, titanium, calcium, and zirconium, oxides or hydroxides of these metals, and their hydrates, or these It is at least 1 type chosen from a metal carbonate, and n, x, y, and z are an integer of 1-5, an integer of 0-10, an integer of 2-5, and an integer of 0-10, respectively. ]
In the above formula (III), when both x and z are 0, the inorganic compound is at least one metal, metal oxide or metal hydroxide selected from aluminum, magnesium, titanium, calcium and zirconium. It will be.

In the present invention, among the above-mentioned inorganic fillers, silica is preferably used from the viewpoint of achieving both low rolling properties and wear resistance.
As the silica that can be used, any commercially available silica can be used. Among them, wet silica, dry silica, and colloidal silica are preferably used, and wet silica is particularly preferably used. The BET specific surface area of silica (measured according to ISO 5794/1) is preferably 40 to 350 m ² / g. Silica having a BET surface area within this range has an advantage that both rubber reinforcement and dispersibility in a rubber component can be achieved. In this respect, BET surface area is more preferably silica in the range of 80~350m ² / g, silica BET surface area in the range of 120~350m ² / g is particularly preferred. Examples of such silica are those manufactured by Tosoh Silica Co., Ltd., trade names “Nipsil AQ” (BET specific surface area = 220 m ² / g), “Nipsil KQ”, and Degussa's trade name “Ultra Gil VN3” (BET specific surface area = 175 m ^2. / G) and other commercial products can be used.

As the inorganic compound represented by the formula (III), for example, .gamma.-alumina, alpha-alumina, such as alumina (Al ₂ O _3), boehmite, alumina monohydrate such as diaspore (Al ₂ O ₃ · H ₂ O), Gibbsite, Bayerite, etc. Aluminum hydroxide [Al (OH) ₃ ], Aluminum carbonate [Al ₂ (CO ₃ ) ₂ ], Magnesium hydroxide [Mg (OH) ₂ ], Magnesium oxide (MgO), Carbonic acid Magnesium (MgCO ₃ ), talc (3MgO · 4SiO ₂ · H ₂ O), attapulgite (5MgO · 8SiO ₂ · 9H ₂ O), titanium white (TiO ₂ ), titanium black (TiO _2n-1 ), calcium oxide (CaO ), calcium hydroxide [Ca (OH) _2], magnesium aluminum oxide _{(MgO · Al 2 O 3)} , clay _{(Al 2 O 3 · 2SiO 2} ), mosquitoes Phosphorus _{(Al 2 O 3 · 2SiO 2} · 2H 2 O), pyrophyllite _{(Al 2 O 3 · 4SiO 2} · H 2 O), bentonite _{(Al 2 O 3 · 4SiO 2} · 2H 2 O), aluminum silicate (Al ₂ SiO ₅ , Al ₄ · 3SiO ₄ · 5H ₂ O, etc.), magnesium silicate (Mg ₂ SiO ₄ , MgSiO ₃ etc.), calcium silicate (Ca ₂ · SiO ₄ etc.), aluminum calcium silicate (Al ₂ O ₃ · CaO · 2SiO ₂ etc.), magnesium calcium silicate (CaMgSiO ₄ ), calcium carbonate (CaCO ₃ ), zirconium oxide (ZrO ₂ ), zirconium hydroxide [ZrO (OH) ₂ · nH ₂ O], carbonic acid zirconium _{[Zr (CO 3) 2]} , crystalline aluminosilicate containing hydrogen to correct, an alkali metal or alkaline earth metal charge as various zeolites Etc. can be used. Further, it is preferable that M ¹ in the formula (I) is at least one selected from aluminum metal, aluminum oxide or hydroxide, hydrates thereof, and aluminum carbonate.

The filler (B) used in the present invention may further contain carbon black in addition to the above-mentioned silica and the inorganic compound represented by the formula (III), if desired. By containing carbon black, it is possible to enjoy the effect of reducing electrical resistance and suppressing charging. The carbon black is not particularly limited. For example, high, medium or low structure SAF, ISAF, IISAF, N339, HAF, FEF, GPF, SRF grade carbon black, particularly SAF, ISAF, IISAF, N339, HAF. It is preferable to use FEF grade carbon black. The nitrogen adsorption specific surface area (N ₂ SA, measured according to JISK6217-2: 2001) is preferably 30 to 250 m ² / g. This carbon black may be used individually by 1 type, and may be used in combination of 2 or more type.
In the present invention, the filler (B) containing an inorganic filler may be used alone or in combination with silica and one or more inorganic compounds represented by the above general formula (III). And carbon black may be used. In the present invention, carbon black is not included in the inorganic filler.

The inorganic filler used in the present invention is preferably used in an amount of 20 to 120 parts by mass with respect to 100 parts by mass of the rubber component (A).
If the blending amount of the inorganic filler is 20 parts by mass or more, it is preferable from the viewpoint of securing wet performance, and if it is 120 parts by mass or less, it is preferable from the viewpoint of reducing rolling resistance. Furthermore, it is more preferable to use 30-100 mass parts.
Moreover, it is preferable to use 10-200 mass parts of fillers (B) containing the said inorganic filler in this invention with respect to 100 mass parts of rubber components (A). If it is 10 mass parts or more, it is preferable from a viewpoint of the reinforcement property improvement of a rubber composition, and if it is 200 mass parts or less, it is preferable from a viewpoint of rolling resistance reduction.
In the total filler (B), the inorganic filler is preferably 5 to 90% by mass, more preferably 30% by mass or more from the viewpoint of both wet performance and rolling resistance. It is particularly preferable that the content is at least mass%.

[Silane coupling agent (C)]
The silane coupling agent (C) used in the production method of the present invention is not particularly limited, and examples thereof include bis (3-triethoxysilylpropyl) tetrasulfide, bis (3-triethoxysilylpropyl) trisulfide, and bis (3 -Triethoxysilylpropyl) disulfide, bis (2-triethoxysilylethyl) tetrasulfide, bis (3-trimethoxysilylpropyl) tetrasulfide, bis (2-trimethoxysilylethyl) tetrasulfide, 3-mercaptopropyltrimethoxy Silane, 3-mercaptopropyltriethoxysilane, 2-mercaptoethyltrimethoxysilane, 2-mercaptoethyltriethoxysilane, 3-nitropropyltrimethoxylane, 3-nitropropyltriethoxysilane, 3-chloropropylmeth Sisilane, 3-chloropropyltriethoxysilane, 2-chloroethyltrimethoxysilane, 2-chloroethyltriethoxysilane, 3-trimethoxysilylpropyl-N, N-dimethylthiocarbamoyl tetrasulfide, 3-triethoxysilylpropyl- N, N-dimethylthiocarbamoyl tetrasulfide, 2-triethoxysilylethyl-N, N-dimethylthiocarbamoyl tetrasulfide, 3-trimethoxysilylpropylbenzothiazole tetrasulfide, 3-triethoxysilylpropylbenzothiazole tetrasulfide, 3 -Triethoxysilylpropyl methacrylate monosulfide, 3-trimethoxysilylpropyl methacrylate monosulfide, bis (3-diethoxymethylsilylpropyl) tetrasulfide 3-mercaptopropyldimethoxymethylsilane, 3-nitropropyldimethoxymethylsilane, 3-chloropropyldimethoxymethylsilane, dimethoxymethylsilylpropyl-N, N-dimethylthiocarbamoyl tetrasulfide, dimethoxymethylsilylpropylbenzothiazole tetrasulfide And at least one of them.
By using these silane coupling agents (C), it is possible to provide a tire tread that is further excellent in workability during rubber processing and has better wear resistance.

  It is preferable that the compounding quantity of the silane coupling agent (C) used for this invention is 1-20 mass% of an inorganic filler. If the amount is less than 1% by mass, the effect of improving the low heat build-up of the tire rubber composition is difficult to be exhibited. If the amount exceeds 20% by mass, the cost of the tire rubber composition becomes excessive and the economy is lowered. Furthermore, it is more preferable that it is 3-20 mass% of an inorganic filler, and it is especially preferable that it is 4-10 mass% of an inorganic filler.

<Alkanolamide (C)>
The alkanolamide represented by the following formula (I) used in the present invention is contained in order to improve the dispersibility of the inorganic filler, particularly the dispersibility of silica, improve the workability and exert the effects of the present invention. Is.
[In the above formula (I), R ₁ represents an alkyl group or alkenyl group having 1 to 24 carbon atoms, and the alkyl group and alkenyl group may be linear, branched or cyclic, , R ₂ is a hydroxyalkyl group or a hydroxyalkyl group having an oxyalkylene unit, and R ₃ is a hydrogen atom, a hydroxyalkyl group or a hydroxyalkyl group having an oxyalkylene unit. ]

In the above formula (I), R ₁ is an alkyl group or alkenyl group having 1 to 24 carbon atoms, and the alkyl group and alkenyl group may be linear, branched or cyclic, for example, methyl Group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, t-butyl group, pentyl group, isopentyl group, hexyl group, isoheptyl group, 2-ethylhexyl group, octyl group, isononyl group, decyl group, dodecyl group Alkyl groups such as isotridecyl group, tetradecyl group, hexadecyl group, isocetyl group, octadecyl group, isostearyl group, docosyl group, tetracosyl group, allyl group, 3-butenyl group, methallyl group, 2-methyl-3-butenyl group, 3-methyl-3-butenyl, 1,1, -dimethyl-2-propenyl, 4-pentenyl, ole An alkenyl group such as an yl group and a tetracosilylene group, preferably an alkyl group or an alkenyl group having 6 to 18 carbon atoms, more preferably 11 to 18 carbon atoms, and the alkyl group and the alkenyl group are linear It may be any of a chain, a branched chain and a ring, and is a heptyl group, 2-ethylhexyl group, undecyl group, tridecyl group, pentadecyl group, heptadecyl group or heptadecenyl group. Preferred examples of the fatty acid used as a raw material for the monoalkanolamide include octanoic acid, lauric acid, tetradecanoic acid, myristic acid, stearic acid, and oleic acid.

In the above formula (I), R ₂ is a hydroxyalkyl group or a hydroxyalkyl group having an oxyalkylene unit. As said alkyl group, a C1-C6 linear or branched alkyl group is preferable, and C2-C3 is more preferable.
R ₃ is a hydrogen atom or a hydroxyalkyl group having a hydroxyalkyl group or an oxyalkylene unit. As said alkyl group, a C1-C6 linear or branched alkyl group is preferable, and C2-C3 is more preferable.
In the present invention, when R ₃ in the above formula (I) selects a hydrogen atom, the alkanolamide represented by the above formula (I) becomes a monoalkanolamide.
Further, when R ₂ and R ₃ in the above formula (I) are a hydroxyalkyl group or a hydroxyalkyl group having an oxyalkylene unit, that is, a dialkanolamide, the following formulas (IV) and ( V) is preferable, R ₄ and R ₅ are each independently an alkylene group having 1 to 6 carbon atoms, and n and m are each preferably a number of 1 to 10, more preferably Is preferably an independent number in which the total number of n and m is 2 to 8.
_{- (R 4 O) n-} H ......... (IV)
_{- (R 5 O) m-} H ......... (V)
Among them, R ₄ and R ₅ are preferably both ethylene group and propylene group, n + m is preferably 2 to 5, and 2 is more preferable. In addition, n and m are independently preferably 1 to 7, more preferably 1 to 4, and more preferably 1. n R ₄ and m R ₅ may be the same or different.

Specific examples of monoalkanolamides represented by the above formula (I) include octanoic acid monoethanolamide, octanoic acid monoisopropanepropanolamide, POE (2) octanoic acid monoethanolamide, lauric acid. Mention may be made of at least one of monoethanolamide, lauric acid monoisopropanolamide, stearic acid monoethanolamide, oleic acid monoethanolamide, POE (2) lauric acid monoethanolamide, among which lauric acid monoisopropanolamide, stearic acid It is desirable to use monoethanolamide, oleic acid monoethanolamide, POE (2) lauric acid monoethanolamide. In addition, the synthesis method of the monoalkanolamide represented by the said formula (I) is known, can be obtained by various manufacturing methods, and may use a commercially available thing.
Examples of the dialkanolamide represented by the above formula (I) include octanoic acid diethanolamide, octanoic acid diisopropanolamide, lauric acid diethanolamide, POE (5) lauric acid diethanolamide, stearic acid diethanolamide, and olein. At least one of acid diethanolamide and POE (5) oleic acid diethanolamide can be mentioned, among which lauric acid diethanolamide, stearic acid diethanolamide, oleic acid diethanolamide, POE (5) oleic acid diethanolamide are used. desirable. In addition, the synthesis method of the dialkanolamide represented by the said formula (I) is known, can be obtained by various manufacturing methods, and may use a commercially available thing.

The (total) content of these component (D) monoalkanolamides and dialkanolamides is 0.5 to 15 parts by weight, more preferably, further effects of the present invention with respect to 100 parts by weight of the rubber component. 3 to 15 parts by mass is preferable, and 3 to 10 parts by mass is more preferable. Moreover, 0.5-20 mass parts is preferable with respect to 100 mass parts of inorganic fillers, as for content of these alkanolamides, 1-15 mass parts is more preferable, and 2-12 mass parts is still more preferable.
When the content of these alkanolamides is 0.5 parts by mass or more with respect to 100 parts by mass of the rubber component, the dispersion effect of the inorganic filler is high.

[Vulcanization accelerator, secondary amine, or salt compound (E) formed from secondary amine and weak acid component]
Examples of the vulcanization accelerator used in the present invention include at least one selected from thiurams, dithiocarbamates, thioureas, xanthates and guanidines.
Examples of thiurams that can be used in the present invention include tetramethyl thiuram disulfide, tetraethyl thiuram disulfide, tetrapropyl thiuram disulfide, tetraisopropyl thiuram disulfide, tetrabutyl thiuram disulfide, tetrapentyl thiuram disulfide, tetrahexyl thiuram disulfide, tetraheptyl. Thiuram disulfide, tetraoctyl thiuram disulfide, tetranonyl thiuram disulfide, tetradecyl thiuram disulfide, tetradodecyl thiuram disulfide, tetrastearyl thiuram disulfide, tetrabenzyl thiuram disulfide, tetrakis (2-ethylhexyl) thiuram disulfide, tetramethyl thiuram monosulfide, tetraethyl thiuram Mo Sulfide, tetrapropyl thiuram monosulfide, tetraisopropyl thiuram monosulfide, tetrabutyl thiuram monosulfide, tetrapentyl thiuram monosulfide, tetrahexyl thiuram monosulfide, tetraheptyl thiuram monosulfide, tetraoctyl thiuram monosulfide, tetranonyl thiuram monosulfide, Examples include tetradecyl thiuram monosulfide, tetradodecyl thiuram monosulfide, tetrastearyl thiuram monosulfide, tetrabenzyl thiuram monosulfide, dipentamethylene thiuram tetrasulfide and the like. Of these, tetrakis (2-ethylhexyl) thiuram disulfide and tetrabenzylthiuram disulfide are preferred because of their high reactivity.

  Examples of dithiocarbamates that can be used in the present invention include zinc dimethyldithiocarbamate, zinc diethyldithiocarbamate, zinc dipropyldithiocarbamate, zinc diisopropyldithiocarbamate, zinc dibutyldithiocarbamate, zinc dipentyldithiocarbamate, and zinc dihexyldithiocarbamate. , Zinc diheptyldithiocarbamate, zinc dioctyldithiocarbamate, zinc di (2-ethylhexyl) dithiocarbamate, zinc didecyldithiocarbamate, zinc didodecyldithiocarbamate, zinc N-pentamethylenedithiocarbamate, N-ethyl-N-phenyldithiocarbamine Zinc oxide, zinc dibenzyldithiocarbamate, copper dimethyldithiocarbamate, copper diethyldithiocarbamate Copper dipropyldithiocarbamate, copper diisopropyldithiocarbamate, copper dibutyldithiocarbamate, copper dipentyldithiocarbamate, copper dihexyldithiocarbamate, copper diheptyldithiocarbamate, copper dioctyldithiocarbamate, copper di (2-ethylhexyl) dithiocarbamate, didecyldithiocarbamate Acid copper, copper dododecyl dithiocarbamate, copper N-pentamethylenedithiocarbamate, copper dibenzyldithiocarbamate, sodium dimethyldithiocarbamate, sodium diethyldithiocarbamate, sodium dipropyldithiocarbamate, sodium diisopropyldithiocarbamate, sodium dibutyldithiocarbamate, dipentyl Sodium dithiocarbamate, dihexyl dithiocar Sodium minate, sodium diheptyldithiocarbamate, sodium dioctyldithiocarbamate, sodium di (2-ethylhexyl) dithiocarbamate, sodium didecyldithiocarbamate, sodium didodecyldithiocarbamate, sodium N-pentamethylenedithiocarbamate, sodium dibenzyldithiocarbamate , Ferric dimethyldithiocarbamate, ferric diethyldithiocarbamate, ferric dipropyldithiocarbamate, ferric diisopropyldithiocarbamate, ferric dibutyldithiocarbamate, ferric dipentyldithiocarbamate, ferric dihexyldithiocarbamate , Ferric diheptyldithiocarbamate, ferric dioctyldithiocarbamate, di (2-ethylhexyl) di Examples thereof include ferric thiocarbamate, ferric didecyldithiocarbamate, ferric didodecyldithiocarbamate, ferric N-pentamethylenedithiocarbamate, ferric dibenzyldithiocarbamate and the like. Of these, zinc dibenzyldithiocarbamate, zinc N-ethyl-N-phenyldithiocarbamate, zinc dimethyldithiocarbamate and copper dimethyldithiocarbamate are preferred because of their high reactivity.

  Examples of thioureas that can be used in the present invention include N, N′-diphenylthiourea, trimethylthiourea, N, N′-diethylthiourea, N, N′-dimethylthiourea, and N, N′-dibutylthiourea. , Ethylenethiourea, N, N′-diisopropylthiourea, N, N′-dicyclohexylthiourea, 1,3-di (o-tolyl) thiourea, 1,3-di (p-tolyl) thiourea, 1, 1-diphenyl-2-thiourea, 2,5-dithiobiurea, guanylthiourea, 1- (1-naphthyl) -2-thiourea, 1-phenyl-2-thiourea, p-tolylthiourea, o-tolylthiourea Etc. Of these, N, N'-diethylthiourea, trimethylthiourea, N, N'-diphenylthiourea and N, N'-dimethylthiourea are preferred because of their high reactivity.

  Examples of xanthates that can be used in the present invention include zinc methylxanthate, zinc ethylxanthate, zinc propylxanthate, zinc isopropylxanthate, zinc butylxanthate, zinc pentylxanthate, zinc hexylxanthate, Zinc heptylxanthate, zinc octylxanthate, zinc 2-ethylhexylxanthate, zinc decylxanthate, zinc dodecylxanthate, potassium methylxanthate, potassium ethylxanthate, potassium propylxanthate, potassium isopropylxanthate, butylxanthate Potassium, potassium pentylxanthate, potassium hexylxanthate, potassium heptylxanthate, octyl Potassium santhate, potassium 2-ethylhexylxanthate, potassium decylxanthate, potassium dodecylxanthate, sodium methylxanthate, sodium ethylxanthate, sodium propylxanthate, sodium isopropylxanthate, sodium butylxanthate, sodium pentylxanthate Sodium hexyl xanthate, sodium heptyl xanthate, sodium octyl xanthate, sodium 2-ethylhexyl xanthate, sodium decyl xanthate, sodium dodecyl xanthate, and the like. Of these, zinc isopropylxanthate is preferable because of its high reactivity.

  Examples of guanidines that can be used in the present invention include 1,3-diphenylguanidine, 1,3-di-o-tolylguanidine, 1-o-tolylbiguanide, and di-o-tolylguanidine salt of dicatechol borate. 1,3-di-o-cumenyl guanidine, 1,3-di-o-biphenyl guanidine, 1,3-di-o-cumenyl-2-propionyl guanidine, and the like may be mentioned, 1,3-diphenyl guanidine, 1,3-di-o-tolylguanidine and 1-o-tolylbiguanide are preferred because of their high reactivity, and 1,3-diphenylguanidine is particularly preferred because of their higher reactivity.

  In the secondary amine used in the present invention or a salt compound formed from a secondary amine and a weak acid component (hereinafter sometimes abbreviated as “secondary amine salt”), the secondary amine is 2 It is not particularly limited as long as it is a compound having a secondary amino group, and any of aliphatic amines and aromatic amines can be used.

  As the aliphatic amine, those having an aliphatic group having 5 to 20 carbon atoms are preferable. For example, dihexylamine, di- (2-ethylhexyl) amine, didecylamine, didodecylamine, ditetradecylamine, dihexaamine. Examples include decylamine, dioctadecylamine, dicyclopentylamine, dicyclohexylamine, dicyclooctylamine, dibenzylamine and diphenethylamine. Of these aliphatic amines, dicyclohexylamine, dibenzylamine, di (2-ethylexyl) amine and dioctadecylamine are preferred.

  On the other hand, as the aromatic amine, an amine having or not having a substituent such as a lower alkyl group on the aromatic ring, or an amine having an aromatic group and an aliphatic group can be used. Examples of such amines include diphenylamine, ditolylamine, dixylylamine, dinaphthylamine, dipyridylamine, dithienylamine, N-phenyl-N-methylamine, N-butyl-N-phenylamine, N-naphthyl-N-methylamine. , N-butyl-N-naphthylamine, N- (2-ethylhexyl) -N-phenylamine, and the like. Of these aromatic amines, diphenylamine, ditolylamine, dinaphthylamine, dipyridylamine, dithienylamine, N-phenyl-N-methylamine and N-butyl-N-naphthylamine are preferred.

  The above aliphatic amines and aromatic amines may be used alone or in combination of two or more thereof. Among these, dicyclohexylamine is preferable from the viewpoint of performance and effects. It is.

The secondary amine salt used is a salt compound formed from at least one secondary amine selected from the aliphatic secondary amines and aromatic secondary amines described above and a weak acid, and the weak acid As, for example, monohydric alcohols such as ethanol, propanol, isopropanol, butanol, isobutanol, pentanol, cyclohexanol, 2-ethylhexanol, decanol and dodecanol, or ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, neo Mention may be made of polyhydric alcohols such as pentyl glycol, trimethylolpropane, glycerol and pentaerythritol.
As the monohydric alcohol, ethanol, butanol and dodecanol are preferable, and as the polyhydric alcohol, ethylene glycol and trimethylolpropane are preferable.

In the present invention, the weak acid used for forming the secondary amine salt may be used alone or in combination of two or more. Among the weak acids, performance and availability are obtained. Ethylene glycol is preferred from the viewpoints of properties and economy. That is, the secondary amine salt is preferably a dicyclohexylamine salt of ethylene glycol.
A mixture of 80% by mass of a dicyclohexylamine salt of ethylene glycol and 20% by mass of a higher alkyl alcohol is commercially available from Ouchi Shinsei Chemical Co., Ltd. as a registered trademark “Knockmaster EGS” (vulcanization activator). Has been.

In the present invention, in the first stage of kneading, the vulcanization accelerator, the secondary amine, or the salt compound (E) formed from the secondary amine and the weak acid component is added and kneaded. As described above, this is to increase the activity of the coupling function of the silane coupling agent (C).
In the present invention, the vulcanization accelerator, or the secondary amine, or the salt compound (E) formed from the secondary amine and the weak acid component may be used alone or in combination. A combination of the above may also be used.

Number of molecules of vulcanization accelerator in the rubber composition for tires in the first stage of kneading according to the present invention, or secondary amine, or salt compound (E) formed from secondary amine and weak acid component ( The number of moles) is preferably 0.1 to 1.0 times the number of molecules (number of moles) of the silane coupling agent (C). This is because the activation of the silane coupling agent (C) occurs sufficiently when the ratio is 0.1 times or more, and the vulcanization speed is not greatly affected when the ratio is 1.0 times or less. More preferably, the number of molecules (number of moles) of the vulcanization accelerator or the secondary amine or the salt compound (E) formed from the secondary amine and the weak acid component is the molecule of the silane coupling agent (C). It is 0.2 to 0.6 times the number (number of moles).
The vulcanization accelerator, or the secondary amine, or the salt compound (E) formed from the secondary amine and the weak acid component is also used as a sulfur vulcanization accelerator. Also, an appropriate amount may be blended if desired.

In the present invention, the vulcanization accelerator, secondary amine, or a salt compound (E) formed from a secondary amine and a weak acid component is suitably suppressed from reducing the activity improvement effect of the coupling function. Therefore, it is preferable to mix an organic acid compound in the rubber composition in the first stage of kneading.
Examples of organic acid compounds that can be used include stearic acid, palmitic acid, myristic acid, lauric acid, arachidic acid, behenic acid, lignoceric acid, capric acid, pelargonic acid, caprylic acid, enanthic acid, caproic acid, and oleic acid. , Organic acids such as saturated fatty acids and unsaturated fatty acids such as vaccenic acid, linoleic acid, linolenic acid and nervonic acid, and resin acids such as rosin acid and modified rosin acid, alkali metals of the saturated fatty acids and unsaturated fatty acids and resin acids Examples thereof include salts and esters. As the alkali metal, sodium, potassium and the like are preferable.
More preferably, 50 mol% or more in the organic acid compound is preferably stearic acid because it is necessary to sufficiently exhibit the function as a vulcanization acceleration aid.
Further, when an emulsion-polymerized styrene-butadiene copolymer is used as a part or all of the rubber component (A), rosin acid (50 mol% or more in the organic acid compound is contained in the emulsion-polymerized styrene-butadiene copolymer ( Modified rosin acid is also included) and / or a fatty acid is preferable from the viewpoint of an emulsifier necessary for polymerizing an emulsion-polymerized styrene-butadiene copolymer.

In the present invention, zinc oxide (zinc white) is preferably added after the second stage of kneading from the viewpoint of unvulcanized viscosity and rolling resistance.
The blending amount of zinc oxide to be used is preferably 0.1 to 5 parts by mass, more preferably 0.1 to 100 parts by mass of the rubber component (A) from the viewpoint of unvulcanized viscosity and rolling resistance. It is desirable to set it as ~ mass part.

In the method for producing a rubber composition for tires of the present invention, various compounding agents such as vulcanization activators such as zinc white and anti-aging agents, which are usually compounded in the rubber composition, are the first stage of kneading as necessary. Alternatively, they are kneaded in the final stage or in an intermediate stage between the first stage and the final stage.
As a kneading apparatus in the production method of the present invention, a Banbury mixer, a roll, an intensive mixer or the like is used.

  In the present invention, in order to more suitably increase the activity of the coupling function of the silane coupling agent (C), the maximum temperature of the rubber composition in the first stage of kneading is 120 to 190 ° C. Preferably, it is 130-175 degreeC, More preferably, it is 140-170 degreeC.

  In the present invention, in the first stage of kneading, all or part of the rubber component (A), the filler (B), all or part of the silane coupling agent (C), and an alkanolamide compound (D ) Is added, and the time until the addition of the vulcanization accelerator, the secondary amine, or the salt compound (E) formed from the secondary amine and the weak acid component during the first stage is 10 It is preferable to set it to -180 seconds. The lower limit of this time is more preferably 30 seconds or more, the upper limit is more preferably 150 seconds or less, and even more preferably 120 seconds or less. If this time is 10 seconds or more, the reaction of (B) and (C) can be sufficiently advanced. Even if this time exceeds 180 seconds, the reaction of (B) and (C) has already proceeded sufficiently, so that it is difficult to enjoy further effects, and the upper limit is preferably set to 180 seconds.

  Further, as a method of adding the vulcanization accelerator in the first stage, or the secondary amine, or the salt compound (E) formed from the secondary amine and the weak acid component, the rubber component (A), the inorganic filler After kneading all or part of (B) and all or part of the silane coupling agent (C) and the alkanolamide compound (D), a vulcanization accelerator, a secondary amine, or a secondary amine It is preferable to add the salt compound (E) formed from the weak acid component and further knead. This is because, by this charging method, the reaction between the silane coupling agent (C) and the rubber component (A) can be advanced after the reaction between the silane coupling agent (C) and the silica has sufficiently progressed.

In the method for producing a rubber composition for tires of the present invention, various compounding agents such as vulcanization activators such as zinc white and anti-aging agents, which are usually compounded in the rubber composition, are the first stage of kneading as necessary. Alternatively, they are kneaded in the final stage or in an intermediate stage between the first stage and the final stage.
As a kneading apparatus in the production method of the present invention, a Banbury mixer, a roll, an intensive mixer or the like is used.

  In the method for producing a rubber composition for a tire of the present invention configured as described above, a filler containing an inorganic filler with respect to the rubber component (A) composed of at least one selected from natural rubber and synthetic diene rubber. (B), a silane coupling agent (C), an alkanolamide compound (D) represented by the above formula (I), a thiuram, a dithiocarbamate, a thiourea, a xanthate and a guanidine A method for producing a rubber composition for a tire comprising at least one vulcanization accelerator, or a secondary amine, or a salt compound (E) formed from a secondary amine and a weak acid component, the rubber Kneading the composition in a plurality of stages, and kneading all or part of (A) and (B) and all or part of (C), (D) and (E) in the first stage of kneading. By inorganic charge Since the dispersibility of the wood is further improved, unvulcanized 硫粘 degree, sheet properties, without impairing the workability such as scorch time, and that the rubber composition for a tire having a sufficiently low heat generation property can be obtained.

  EXAMPLES Next, although an Example is given and this invention is demonstrated in more detail, this invention is not limited to the following Example at all.

(Examples 1-5 and Comparative Examples 1-3)
A rubber composition for a tire tread was prepared according to the formulation and kneading method shown in Table 1 below (first stage of kneading + final stage of kneading).
In Examples 1 to 5, each component was adjusted in the first stage of kneading in Table 1 so that the maximum temperature of the rubber composition in the first stage of kneading was 150 ° C., and kneaded with a Banbury mixer. A tire rubber composition was prepared. In the first stage of kneading the tire rubber composition, 60 seconds had elapsed after kneading all of the rubber component (A), the filler (B), the silane coupling agent (C) and the alkanolamide compound (D). Thereafter, 1,3-diphenylguanidine (DPG), which is a guanidine, was added as a vulcanization accelerator (E) and further kneaded to prepare a rubber composition for each tire tread.
In Comparative Examples 1 to 3, a rubber composition for a tire tread was prepared in the same manner as in Examples 1 to 5 except that the alkanolamide compound (D) was not blended.
The unvulcanized viscosity, sheet properties, scorch time, and rolling resistance of each obtained rubber composition for tire were calculated and evaluated by the following methods.
These results are shown in Table 1 below.

[Measurement method of unvulcanized rubber viscosity and scorch time]
The unvulcanized rubber viscosity and scorch time were determined in accordance with JIS K 6300-1: 2001 (Mooney viscosity, Mooney scorch time).
The evaluation was expressed as an index with the value of Comparative Example 1 being 100. The smaller the unvulcanized rubber viscosity, the better the workability. The larger the value, the slower the start of vulcanization, and the smaller the value, the faster the vulcanization start. Indicates unfavorable conditions such as burning.

(Evaluation method for sheet properties)
Using a Garvey die extruder (manufactured by Brabender), the skin surface roughness of the molded product obtained by extruding each rubber composition was visually evaluated, and the surface skin condition was sensory evaluated according to the following evaluation criteria. .
Evaluation criteria:
◎: Best ○: Good △: Acceptable ×: Impossible

(Rolling resistance index evaluation method)
The tire of size 195 / 65R15 was rotated at a speed of 80 km / h by a rotating drum, the load was 4.41 kN, and the rolling resistance was measured. The reciprocal of the rolling resistance of the control tire (Comparative Example 1) was expressed as an index with the reciprocal being 100. It means that rolling resistance is so low that an index value is large.

* 1 to * 11 in Table 1 are as follows.
* 1: Solution polymerization SBR manufactured by Asahi Kasei Co., Ltd., trade name “Toughden 2000”
* 2: Sankyo Oil Chemical Co., Ltd., trade name “A / O MIX”
* 3: Asahi Carbon Co., Ltd., trade name “# 80”
* 4: Tosoh Silica Co., Ltd., nip seal AQ, BET surface area of 220 m ² / g
* 5: Bis (3-triethoxysilylpropyl) disulfide (average sulfur chain length: 2.3)
5) Silane coupling agent manufactured by Evonik, trade name “Si75” (registered trademark)
* 6: Aminone L-02 [Lauric acid diethanolamide, manufactured by Kao Corporation]
* 7: N- (1,3-dimethylbutyl) -N′-phenyl-p-phenylenediamine,
Product name "NOCRACK 6C", manufactured by Ouchi Shinsei Chemical Co., Ltd.
* 8: Processability improver (processability aid); Actiplast PP, manufactured by Rhein Chemie, a mixture of saturated fatty acid zinc salts, melting point 102 ° C
* 9: Noxeller D, manufactured by Ouchi Shinsei Chemical Co., Ltd., 1,3-diphenylguanidine * 10: Noxeller CZ, manufactured by Ouchi Shinsei Chemical Co., Ltd., N-cyclohexyl-2-benzothiazolylsulfur Fenamide,
* 11: Noxeller DM, manufactured by Ouchi Shinsei Chemical Co., Ltd., dibenzothiazolyl sulfide

As is clear from the results of Tables 1 and 2, the tire rubber compositions of Examples 1 to 5 were compared with the tire rubber compositions to be compared in Comparative Examples 1 to 5, and the unvulcanized viscosity. It has been found that the rubber composition for tires has a sufficiently low exothermic property without impairing processability such as sheet properties and scorch time.
Looking at the comparative examples, since Comparative Examples 1 to 3 are rubber compositions for tire treads that do not contain the alkanolamide compound (D), workability such as unvulcanized viscosity, sheet properties, and scorch time is not impaired. It was found that sufficient low heat build-up cannot be exhibited.

  The method for producing a rubber composition for tires of the present invention can provide a rubber composition for tires having sufficiently low heat generation without impairing processability, so for passenger cars, light trucks, mini passenger cars, It is preferably used as a method for manufacturing various members of pneumatic tires for light trucks and large vehicles (for trucks, buses, construction vehicles, etc.), particularly tread members for pneumatic radial tires.

Claims (5)

For the rubber component (A) composed of at least one selected from natural rubber and synthetic diene rubber, a filler (B) containing an inorganic filler, a silane coupling agent (C), and the following formula (I) And at least one vulcanization accelerator selected from thiurams, dithiocarbamates, thioureas, xanthates and guanidines, or secondary amines or secondarys A method for producing a tire rubber composition comprising at least a salt compound (E) formed from an amine and a weak acid component,
The rubber composition is kneaded in a plurality of stages, and in the first stage of kneading, all or part of the rubber component (A), the filler (B), and all or one of the silane coupling agent (C). Part of the alkanolamide compound (D) and the vulcanization accelerator, or the secondary amine, or the salt compound (E) formed from the secondary amine and the weak acid component , and the zinc oxide is kneaded. A method for producing a rubber composition for tires, which is introduced after the second stage .
[In the above formula (I), R ₁ represents an alkyl group or alkenyl group having 1 to 24 carbon atoms, and the alkyl group and alkenyl group may be linear, branched or cyclic, , R ₂ is a hydroxyalkyl group or a hydroxyalkyl group having an oxyalkylene unit, and R ₃ is a hydrogen atom, a hydroxyalkyl group or a hydroxyalkyl group having an oxyalkylene unit. ]   The method for producing a tire rubber composition according to claim 1, wherein the maximum temperature of the rubber composition in the rubber composition in the first stage of the kneading is 120 to 190 ° C. Wherein the filler (B) is silica and include carbon black, per 100 parts by mass weight of the rubber component (A) of the filler (B), 請 Motomeko 1 Ru 10-200 parts by der Or the manufacturing method of the rubber composition for tires of 2.   The method for producing a rubber composition for a tire according to claim 3, wherein the content of the silica is 5 to 90 mass% in the entire filler (B). The manufacturing method of the rubber composition for tires as described in any one of Claims 1-4 whose compounding quantity of a zinc oxide is 0.1-5 mass parts with respect to 100 mass parts of rubber components (A).