JP2017218496A - Production method of rubber composition for tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a production method of a rubber composition for a tire, by which a silane reaction is sufficiently promoted compared to the prior arts in the production of a rubber composition for a tire with silica compounded therein, and thereby a rubber composition having sufficiently dispersed silica can be efficiently produced.SOLUTION: The production method of a rubber composition for a tire aims to produce a rubber composition for a tire in which silica and a silane coupling agent are compounded in a polymer, by supplying and kneading the silica and the silane coupling agent in a kneading step by use of a sealed rubber kneader. In the kneading step, water produced by the silane reaction between the silica and the silane coupling agent is removed in the sealed rubber kneader.SELECTED DRAWING: None

Description

  The present invention relates to a method for producing a rubber composition for a tire containing silica.

  In a pneumatic tire, wet grip performance and rolling resistance (low fuel consumption) are contradictory performances, but in recent years, there is an increasing need for compatibility between the two contradictory performances.

  Therefore, in order to meet this need, silica is added to a polymer such as natural rubber (NR) in the production of a rubber composition for tires (hereinafter also simply referred to as “rubber composition”) used in an extruded product such as a tread. Mixing as a filler is performed (for example, Patent Documents 1 and 2).

  However, since silica is not directly bonded to these polymers, the rubber composition with sufficiently improved wet grip performance and rolling resistance cannot be provided simply by blending silica.

  Therefore, conventionally, in the kneading step, a silane coupling agent containing an alkoxyl group is blended with silica, and the silica and the silane coupling agent are reacted (silane reaction), whereby the silica and the silane coupling agent are reacted with each other. Bonding with a polymer is performed. Further, as a polymer, a terminal-modified polymer in which a group having reactivity with silica is introduced at the terminal is also used.

  In the production of a composition containing this silica, a closed rubber kneader such as a Banbury mixer is usually used as the rubber kneader. At the time of kneading, a sufficient amount of heat is supplied to the silane reaction. If the reaction is sufficiently performed and silica is not uniformly dispersed in the rubber composition, the above-described performances cannot be exhibited sufficiently.

  For this reason, the kneading process is divided into two stages (the first kneading process and the second kneading process), and the silica and the silane coupling agent are added in two portions. A kneading method that controls not only the kneading time but also the kneading temperature is generally employed.

Japanese Patent No. 4806438 Japanese Patent No. 5567302

  However, water is generated as a by-product in the silane reaction described above. And since the silane reaction is a reversible reaction, if the kneading operation is performed with the generated water present, the progress of the silane reaction is hindered, resulting in poor dispersion of the silica, and the rubber composition after kneading. There is a risk that characteristics such as tan δ, which is an index of low fuel consumption performance, will deteriorate.

  In addition, when the kneaded work is performed without removing the generated water from the rubber kneader, when the kneaded kneaded product is discharged to an under banbury or roll, water drops are attached to the surface of the kneaded product, There is a risk of causing a roll slip.

  The occurrence of such a roll slip generates a gel in the kneaded material and raises the Mooney viscosity, which causes deterioration of workability and causes sheet breakage during sheeting of the discharged kneaded material. Then, there is a risk of causing a defective sheeting fabric.

  Therefore, for example, a ram (floating weight) such as a Banbury mixer is raised during kneading to degas water generated by the silane reaction as steam, or the kneaded product is transferred to a tandem mixer and further kneaded to produce steam. Although it has been proposed to sufficiently deaerate and promote sufficient silane reaction and sufficient dispersion of silica, these methods are not efficient methods and have characteristics such as tan δ described above. Since it could not be said that the deterioration of the fabric and the occurrence of defective fabrics were sufficiently prevented, further ingenuity is required.

  Therefore, the present invention efficiently produces a rubber composition in which the silane reaction is sufficiently promoted and the silica is sufficiently dispersed in the production of a rubber composition for a tire containing silica. It is an object of the present invention to provide a method for producing a rubber composition for a tire that can be used.

  The inventor has intensively studied and found that the above-described problems can be solved by the invention described below, and has completed the present invention.

The invention described in claim 1
A rubber composition for a tire in which silica and a silane coupling agent are blended in a polymer is kneaded by introducing the silica and the silane coupling agent in a kneading step using a hermetic rubber kneader. A method for producing a tire rubber composition to be produced, comprising:
In the kneading step, water generated by a silane reaction between the silica and the silane coupling agent is removed in the hermetic rubber kneader.

The invention described in claim 2
The kneading step has a kneading step of two or more stages, and the silica and the silane coupling agent are added to each kneading step and kneaded,
The water generated by the silane reaction of the silica and the silane coupling agent in at least one kneading step among the two or more kneading steps is removed in the hermetic rubber kneader. It is a manufacturing method of the rubber composition for tires of Claim 1.

The invention according to claim 3
The kneading step has a two-stage kneading step of a first kneading step and a second kneading step, and the silica and the silane coupling agent are mixed with the first kneading step and the second kneading step. It is divided into two stages of the kneading process, and kneaded.
The water generated by the silane reaction of the silica and the silane coupling agent in the first kneading step and / or the second kneading step is removed in the hermetic rubber kneader. Item 3. A method for producing a rubber composition for a tire according to Item 2.

The invention according to claim 4
The polymer includes at least a polymer of natural rubber, styrene butadiene rubber, butadiene rubber,
The rubber composition for a tire is a rubber composition containing 30 to 120 parts by mass of the silica and 1 to 20 parts by mass of the silane coupling agent with respect to 100 parts by mass of the polymer. It is a manufacturing method of the rubber composition for tires of any one of Claim 1 thru | or 3.

The invention described in claim 5
5 to 70 parts by mass of a modified styrene butadiene rubber modified with a compound represented by the following formula (1) and having a bound styrene content of 21% by mass or less is contained in 100 parts by mass of the polymer. The method for producing a rubber composition for a tire according to claim 4.

In the formula, R ¹ , R ² and R ³ represent an alkyl group, an alkoxy group, a silyloxy group, an acetal group, a carboxyl group, a mercapto group or a derivative thereof, and R ⁴ and R ⁵ are a hydrogen atom or an alkyl group. Represents a group. N represents a positive integer.

The invention described in claim 6
The method for producing a rubber composition for a tire according to any one of claims 1 to 5, wherein the closed rubber kneader is a Banbury mixer.

The invention described in claim 7
The tire according to claim 6, wherein a steam degassing duct with a filter is provided in a chamber of the Banbury mixer, and water generated by the silane reaction is removed by the water vapor degassing duct. It is a manufacturing method of the rubber composition.

The invention according to claim 8 provides:
The method for producing a rubber composition for a tire according to any one of claims 1 to 7, wherein the rubber composition for a tire is a rubber composition for a tread rubber.

The invention according to claim 9 is:
Furthermore, a finishing step is provided in which a vulcanizing agent and a vulcanization accelerator are added to the kneaded product obtained in the kneading step and kneaded.
The method for producing a rubber composition for a tire according to any one of claims 1 to 8, wherein the kneaded product is kneaded until the temperature of the kneaded product becomes 90 to 120 ° C in the finishing step.

  According to the present invention, when producing a rubber composition for a tire containing silica, the rubber composition in which the silane reaction is sufficiently promoted and the silica is sufficiently dispersed is produced more efficiently than in the past. The manufacturing method of the rubber composition for tires which can be provided can be provided.

It is the schematic of the Banbury mixer used in the manufacturing method of the rubber composition for tires which concerns on one embodiment of this invention.

1. Summary of the Invention Conventionally, carbon blending with a low moisture content has been mainly used, and there was no need for water vapor removal, and the carbon / filler before being taken into the rubber is collected, resulting in variations in the specific gravity of the rubber. Therefore, no water removing means such as a steam degassing duct is provided in the rubber kneader.

  On the other hand, in the kneading step, when the present invention is produced by kneading a rubber composition for a tire in which silica and a silane coupling agent are blended with a polymer using a hermetic rubber kneader. The water generated by the silane reaction of silica and the silane coupling agent is removed in a rubber kneader.

  That is, by providing a steam degassing duct (for example, a steam degassing duct with a filter) in the rubber kneader, the ram (floating weight) is raised during kneading as in the conventional method, Even if the kneaded product is not transferred to a tandem mixer and further kneaded, the water generated by the silane reaction can be removed while kneading, and the silane reaction is sufficiently promoted to sufficiently disperse the silica. The produced rubber composition can be efficiently produced.

  As a result of further investigation by the present inventors, the polymer was modified with a compound represented by the following formula (1) excellent in reactivity with silica, and the modified styrene having a bound styrene content of 21% by mass or less. It has been found that when a polymer containing an appropriate amount of butadiene rubber (modified SBR) is used, a rubber composition in which the silane reaction is sufficiently accelerated and silica is sufficiently dispersed can be produced.

In the formula, R ¹ , R ² and R ³ represent an alkyl group, an alkoxy group, a silyloxy group, an acetal group, a carboxyl group, a mercapto group or a derivative thereof, and R ⁴ and R ⁵ are a hydrogen atom or an alkyl group. Represents a group. N represents a positive integer.

2. Embodiments of the Present Invention Hereinafter, embodiments of the present invention will be specifically described. In the following, the rubber kneader used in the present embodiment will be described first, and then the kneading process performed using this rubber kneader will be described. Furthermore, raw materials including the polymer used in the present embodiment and silica and a silane coupling agent will be described.

(1) Rubber kneader FIG. 1 is a schematic view of a Banbury mixer used in the method for producing a tire rubber composition according to the present embodiment, except for a steam degassing duct (not shown). It has basically the same configuration as the Banbury mixer used more. In the present embodiment, the rubber kneader is not limited to the above-described Banbury mixer as long as it is a closed rubber kneader.

  As shown in FIG. 1, the Banbury mixer 11 includes a kneading chamber 13 having a pair of agitating rotors 12 and 12 arranged in parallel. The polymer and other raw materials are charged into the kneading chamber 13 to perform kneading. After the kneading is completed, the kneaded material is discharged from the openable discharge port 14 provided in the kneading chamber 13 and formed into a sheet, which is the same as the conventional one.

  However, in the present embodiment, the kneading chamber 13 is provided with an openable / closable steam degassing duct (not shown), and the steam degassing duct is appropriately opened during kneading. However, it is different from the conventional one in that water produced by the silane reaction can be degassed and removed from the kneading chamber as water vapor while kneading. The steam degassing duct can be provided on the wall surface of the kneading chamber in the kneader by adding control to operate the dust collector after the filler is mixed.

  The stirring rotor 12 has a well-known configuration in which a stirring blade is provided around a base shaft that is rotatably supported, for example, in a spiral shape, and is disposed in a kneading chamber 13 provided in the kneading machine main body 15. Each agitating rotor 12 is rotationally driven in the same direction or in the opposite direction via drive means (not shown) including a motor attached to the kneader main body 15.

  The kneading chamber 13 has a cross-sectional gourd shape in which two circumferential surfaces concentric with the pair of stirring rotors 12 and 12 are connected, and the constricted portion is charged with an inlet 16 for introducing the raw material rubber, silica and the like. The lower end of the vertical hole 17 leading to is connected. A ram (floating weight) 18 supported by a cylinder or the like so as to be movable up and down is disposed in the vertical hole 17. By lowering the ram 18, the raw rubber, silica and the like put in the kneading chamber 13 are pressurized, and the stirring efficiency and kneading efficiency by the stirring rotor 12 are improved.

  The kneading machine main body 15 is provided with a drop door 19 that opens and closes a discharge port 14 formed in the lower portion of the kneading chamber 13, and the kneaded material is discharged and dropped from the discharge port 14 as a lump by opening the drop door 19. .

(2) Kneading process Next, the kneading process of the rubber composition using the rubber kneader (Banbury mixer 11) having the above-described configuration will be described. In the following description, kneading is performed in the same first kneading step and second kneading step as in the prior art, but the present invention is not limited to this, and kneading is performed in a single kneading step. Alternatively, the kneading may be carried out in three or more kneading steps.

(A) First kneading step First, the entire amount of the polymer and a part of the raw material containing silica and the silane coupling agent are put into the Banbury mixer 11, and the number of revolutions and electric power of the stirring rotor 12 are appropriately controlled. Kneading for a predetermined time. Thereby, the temperature of a kneaded material rises, the silane reaction of a silica and a silane coupling agent advances, and dispersion | distribution of a silica advances.

  Here, the total amount of raw materials including silica and silane coupling agent is not added, but a part of it is added because silica has silanol groups on the surface and has a characteristic that it is more likely to aggregate than carbon. For this reason, when the entire amount is supplied at a time and kneaded, the dispersibility of the silica in the polymer may decrease due to the aggregation of the silica.

  The kneaded first kneaded material is then discharged and dropped from the discharge port 14 opened by the opening operation of the drop door 19 to form a sheet.

(B) Second kneading step Next, the entire amount of the first kneaded material made into a sheet is put into the Banbury mixer 11 together with the remainder of the raw materials, and similarly, while appropriately controlling the rotation speed and power of the stirring rotor 12 Kneading for a predetermined time. Thereby, the temperature of the kneaded product rises, the silane reaction between the silica and the silane coupling agent proceeds, and the dispersion of silica further proceeds.

  Then, the kneaded second kneaded product is discharged and dropped from the discharge port 14 opened by the opening operation of the drop door 19 to form a sheet.

(C) Removal of Water Generated by Silane Reaction Next, removal of water generated by the silane reaction, which is a characteristic part in the present embodiment, will be described.

  In the present embodiment, water generated by the silane reaction is removed in the kneading chamber 13 in one or both of the first kneading step and the second kneading step. As a result, water can be discharged more efficiently compared to the conventional method of removing water by raising floating weights such as a Banbury mixer during kneading and the method of removing water by additional kneading using a tandem mixer. Since it can be removed, the silane reaction can be further promoted, silica can be sufficiently dispersed, and shortening of the kneading time can also be expected.

  Specifically, for example, a steam degassing duct with a filter (not shown) is provided in the kneading chamber 13 of the Banbury mixer 11, and after proceeding to the dispersion step, the steam degassing duct is opened to degas the steam. By controlling so as to be started, water generated by the silane reaction can be efficiently removed from the steam degassing duct with a filter while the kneading proceeds.

  The suction force of the steam degassing duct is appropriately set according to the size of the kneading chamber 13 of the Banbury mixer 11, the mass of the kneaded material to be charged, the amount of water to be generated, and the like.

(D) Finishing step In the present embodiment, the entire amount of the second kneaded material formed into a sheet is charged into the Banbury mixer 11 together with the vulcanizing agent and the vulcanization accelerator as in the conventional case, and similarly, the stirring rotor It is preferable to provide a finishing step in which the rubber composition is finished by kneading for a predetermined time while appropriately controlling the number of revolutions and power of 12. Thus, in this Embodiment, since all the kneading | mixing processes and finishing processes can be performed with one Banbury mixer, a rubber composition can be manufactured more efficiently.

  The tire rubber composition manufactured in the present embodiment may be any of various rubber compositions for tire members such as for tread rubber and sidewall rubber, and any of the methods according to the present embodiment. In particular, it can be preferably applied to the production of a rubber composition for tread rubber, which is strongly required to achieve both wet grip performance and rolling resistance (low fuel consumption). .

(3) Polymer and Raw Material Next, the polymer used in the present embodiment will be described, and further, the raw material containing silica and a silane coupling agent will be described.

(A) Polymer In the present embodiment, as the polymer, natural rubber (NR), styrene butadiene rubber (SBR), and butadiene rubber (BR) generally used in the tire industry are appropriately selected and used. , May be used in combination.

  And in this Embodiment, as above-mentioned, it is preferable to use modified | denatured SBR modified | denatured by the compound represented by following formula (1) as SBR, and the amount of bond styrene is 21 mass% or less.

In the formula, R ¹ , R ² and R ³ represent an alkyl group, an alkoxy group, a silyloxy group, an acetal group, a carboxyl group, a mercapto group or a derivative thereof, and R ⁴ and R ⁵ are a hydrogen atom or an alkyl group. Represents a group. N represents a positive integer.

  As described above, since such modified SBR has excellent reactivity with silica, when this modified SBR is kneaded with silica and a silane coupling agent, the silane reaction is further sufficiently promoted, and the silica is sufficient. A rubber composition dispersed in can be produced.

In R ¹ , R ² and R ³ shown in the above formula (1), examples of the alkyl group include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, and a t-butyl group. Examples thereof include an alkyl group having 1 to 4 carbon atoms.

  Examples of the alkoxy group include an alkoxy group having 1 to 8 carbon atoms such as a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, an n-butoxy group, and a t-butoxy group (preferably having a carbon number of 1 to 6, More preferably, C1-4) etc. are mentioned. The alkoxy group includes a cycloalkoxy group (cycloalkoxy group having 5 to 8 carbon atoms such as cyclohexyloxy group) and an aryloxy group (aryloxy group having 6 to 8 carbon atoms such as phenoxy group and benzyloxy group). ) Is also included.

  Examples of the silyloxy group include a silyloxy group substituted with an aliphatic group having 1 to 20 carbon atoms and an aromatic group (trimethylsilyloxy group, triethylsilyloxy group, triisopropylsilyloxy group, diethylisopropylsilyloxy group, t -Butyldimethylsilyloxy group, t-butyldiphenylsilyloxy group, tribenzylsilyloxy group, triphenylsilyloxy group, tri-p-xylylsilyloxy group, etc.).

  Examples of the acetal group include groups represented by -C (RR ')-OR "and -O-C (RR')-OR". Specifically, the former includes a methoxymethyl group, an ethoxymethyl group, a propoxymethyl group, a butoxymethyl group, an isopropoxymethyl group, a t-butoxymethyl group, a neopentyloxymethyl group, and the like. Methoxy group, ethoxymethoxy group, propoxymethoxy group, i-propoxymethoxy group, n-butoxymethoxy group, t-butoxymethoxy group, n-pentyloxymethoxy group, n-hexyloxymethoxy group, cyclopentyloxymethoxy group, cyclohexyloxy A methoxy group etc. can be mentioned.

Furthermore, examples of the alkyl group in R ⁴ and R ⁵ include the same groups as the alkyl groups described above.

  Moreover, as n (positive integer), 1-5 are preferable. Thereby, both low exothermic property and high rubber strength can be suitably achieved. Furthermore, n is more preferably 2 to 4, and most preferably 3. When n is 0, it is difficult to bond a silicon atom and a nitrogen atom, and when n is 6 or more, the effect as a modifier is reduced.

  Specific compounds represented by the above formula (1) include 3-aminopropyldimethylmethoxysilane, 3-aminopropylmethyldimethoxysilane, 3-aminopropylethyldimethoxysilane, 3-aminopropyltrimethoxysilane, 3- Aminopropyldimethylethoxysilane, 3-aminopropylmethyldiethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropyldimethylbutoxysilane, 3-aminopropylmethyldibutoxysilane, dimethylaminomethyltrimethoxysilane, 2-dimethyl Aminoethyltrimethoxysilane, 3-dimethylaminopropyltrimethoxysilane, 4-dimethylaminobutyltrimethoxysilane, dimethylaminomethyldimethoxymethylsilane, 2-dimethylaminoethyldimethoxy Methylsilane, 3-dimethylaminopropyldimethoxymethylsilane, 4-dimethylaminobutyldimethoxymethylsilane, dimethylaminomethyltriethoxysilane, 2-dimethylaminoethyltriethoxysilane, 3-dimethylaminopropyltriethoxysilane, 4-dimethylaminobutyl Triethoxysilane, dimethylaminomethyldiethoxymethylsilane, 2-dimethylaminoethyldiethoxymethylsilane, 3-dimethylaminopropyldiethoxymethylsilane, 4-dimethylaminobutyldiethoxymethylsilane, diethylaminomethyltrimethoxysilane, 2- Diethylaminoethyltrimethoxysilane, 3-diethylaminopropyltrimethoxysilane, 4-diethylaminobutyltrimethoxysilane, diethylamino Tildimethoxymethylsilane, 2-diethylaminoethyldimethoxymethylsilane, 3-diethylaminopropyldimethoxymethylsilane, 4-diethylaminobutyldimethoxymethylsilane, diethylaminomethyltriethoxysilane, 2-diethylaminoethyltriethoxysilane, 3-diethylaminopropyltriethoxysilane 4-diethylaminobutyltriethoxysilane, diethylaminomethyldiethoxymethylsilane, 2-diethylaminoethyldiethoxymethylsilane, 3-diethylaminopropyldiethoxymethylsilane, 4-diethylaminobutyldiethoxymethylsilane, and the like. These may be used alone or in combination of two or more.

  And as a modification | denaturation method of SBR by the compound (modifying agent) represented by the said Formula (1), conventionally well-known methods, such as the method described in Japanese Patent Publication No. 6-53768, Japanese Patent Publication No. 6-57767, etc. Can be used. For example, SBR may be brought into contact with a modifying agent, SBR is synthesized by polymerization, a method of adding a predetermined amount of the modifying agent to the synthesized polymer rubber solution, and a reaction is performed by adding the modifying agent to the SBR solution. Methods and the like.

  At this time, in the obtained modified SBR, when the amount of bound styrene exceeds 21% by mass, the polymer compatibility may be lowered. Therefore, the amount of bound styrene is preferably 21% by mass or less.

  And in this Embodiment, it is preferable that the quantity of the said modification | denaturation SBR which occupies for 100 mass parts of polymers is 5-70 mass parts. When the amount is less than 5 parts by mass, the silica dispersibility improving effect due to the modification effect tends to be small. On the other hand, when it exceeds 70 mass parts, there exists a possibility that the intensity | strength of rubber | gum may become inadequate.

(B) Raw material (I) Silica Silica is not particularly limited, and for example, silica (anhydrous silicic acid) prepared by a dry method, silica (hydrous silicic acid) prepared by a wet method, and the like can be used. . Among these, it is preferable to use silica prepared by a wet method because there are many silanol groups on the surface and many reactive sites with the silane coupling agent.

  The average primary particle diameter of silica is preferably 10 nm or more, more preferably 15 nm or more. If it is less than 10 nm, it tends to be inferior in low heat build-up and rubber processability. The average primary particle diameter of silica is preferably 40 nm or less, more preferably 30 nm or less. If it exceeds 40 nm, the fracture strength tends to decrease. In addition, the average primary particle diameter of silica can be calculated | required from the average value which observes a silica with an electron microscope, measures a particle diameter about 50 arbitrary particles, for example.

At this time, silica nitrogen adsorption specific surface area _(N 2 SA) is preferably at least ^{50 m} 2 / g, more preferably a ^{80 m} 2 / g or more. If it is less than 50 m ² / g, the reinforcing property of silica is low, and there is concern about durability. The N ₂ SA of silica is preferably 250 m ² / g or less, more preferably 220 m ² / g or less. If it exceeds 250 m ² / g, kneading may be difficult. The _N 2 SA of silica is measured by BET method in accordance with ASTM D3037-81.

  In this Embodiment, the compounding quantity of a silica shall be 30-120 mass parts with respect to 100 mass parts of polymers. If the amount is less than 30 parts by mass, a sufficient effect due to silica blending cannot be obtained, and the balance between fuel efficiency and wet grip performance tends to deteriorate. On the other hand, when it exceeds 120 parts by mass, it is difficult to disperse the silica, which may make it difficult to process.

(B) Silane coupling agent As the silane coupling agent that can be used in the present invention, any silane coupling agent that has been conventionally used in combination with silica can be used. For example, bis (3-triethoxysilylpropyl) tetra Sulfide, bis (2-triethoxysilylethyl) tetrasulfide, bis (4-triethoxysilylbutyl) tetrasulfide, bis (3-trimethoxysilylpropyl) tetrasulfide, bis (2-trimethoxysilylethyl) tetrasulfide, Bis (4-trimethoxysilylbutyl) tetrasulfide, bis (3-triethoxysilylpropyl) trisulfide, bis (2-triethoxysilylethyl) trisulfide, bis (4-triethoxysilylbutyl) trisulfide, bis ( 3-trimethoxysil Rupropyl) trisulfide, bis (2-trimethoxysilylethyl) trisulfide, bis (4-trimethoxysilylbutyl) trisulfide, bis (3-triethoxysilylpropyl) disulfide, bis (2-triethoxysilylethyl) disulfide Bis (4-triethoxysilylbutyl) disulfide, bis (3-trimethoxysilylpropyl) disulfide, bis (2-trimethoxysilylethyl) disulfide, bis (4-trimethoxysilylbutyl) disulfide, 3-trimethoxysilyl Propyl-N, N-dimethylthiocarbamoyl tetrasulfide, 3-triethoxysilylpropyl-N, N-dimethylthiocarbamoyl tetrasulfide, 2-triethoxysilylethyl-N, N-dimethylthiocarbamoyl tet Sulfide, 2-trimethoxysilylethyl-N, N-dimethylthiocarbamoyl tetrasulfide, 3-trimethoxysilylpropylbenzothiazolyl tetrasulfide, 3-triethoxysilylpropylbenzothiazole tetrasulfide, 3-triethoxysilylpropyl methacrylate Sulfides such as monosulfide, 3-trimethoxysilylpropyl methacrylate monosulfide, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 2-mercaptoethyltrimethoxysilane, 2-mercaptoethyltriethoxysilane, etc. Mercapto type, vinyl type such as vinyltriethoxysilane, vinyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropylto Amino group such as methoxysilane, 3- (2-aminoethyl) aminopropyltriethoxysilane, 3- (2-aminoethyl) aminopropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-glycidoxy Glycidoxy series such as propyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, nitro series such as 3-nitropropyltrimethoxysilane, 3-nitropropyltriethoxysilane, Examples include chloro-based compounds such as 3-chloropropyltrimethoxysilane, 3-chloropropyltriethoxysilane, 2-chloroethyltrimethoxysilane, and 2-chloroethyltriethoxysilane. Of these, Si69 (bis (3-triethoxysilylpropyl) tetrasulfide) and Si266 (bis (3-triethoxysilylpropyl) disulfide) are preferable from the viewpoint of coupling treatment efficiency and processability in a kneader.

  In this Embodiment, it is preferable that the compounding quantity of a silane coupling agent shall be 1-20 mass parts with respect to 100 mass parts of polymers. If the amount is less than 1 part by mass, the amount of silica is too small, the silane reaction does not proceed sufficiently, and the effect of improving the physical properties (such as increasing fracture strength and reducing rolling resistance) is achieved by adding a silane coupling agent. There is a small tendency. On the other hand, when it exceeds 20 mass parts, it is too much with respect to the compounding quantity of a silica, and there exists a possibility that an excess silane coupling agent may remain | survive without reacting.

(C) Carbon black In the present embodiment, carbon black may be blended. Thereby, the intensity | strength of rubber | gum can be improved. As carbon black, GPF, HAF, ISAF, SAF, etc. can be used, for example.

When carbon black is used, the N ₂ SA of the carbon black is preferably 30 m ² / g or more, and more preferably 70 m ² / g or more. When N ₂ SA is less than 30 m ² / g, there is a tendency that sufficient reinforcing properties cannot be obtained. Also, _N 2 SA of carbon black is preferably 250 meters ² / g or less, more preferably 150m ² / g. When N ₂ SA exceeds 250 m ² / g, the viscosity at the time of unvulcanization becomes very high, and the processability tends to deteriorate and the fuel consumption tends to deteriorate. In addition, N ₂ SA of carbon black is obtained by JIS K6217, method A in item 7.

  The content of carbon black is preferably 10 parts by mass or more, more preferably 20 parts by mass or more with respect to 100 parts by mass of the rubber component. If the amount is less than 10 parts by mass, sufficient reinforcing properties tend not to be obtained. Moreover, Preferably it is 60 mass parts or less, More preferably, it is 50 mass parts or less. When it exceeds 60 parts by mass, the heat generation tends to increase.

(D) Other raw materials In the present embodiment, in addition to the above-mentioned silica, silane coupling agent, and carbon black, a compounding agent generally used in the production of a rubber composition, for example, a reinforcing filler such as clay Zinc oxide, stearic acid, various anti-aging agents, oils such as aroma oil, vulcanizing agents such as wax and sulfur, vulcanization accelerators, and the like can be appropriately blended.

  Hereinafter, based on an Example, this invention is demonstrated more concretely.

1. Outline In the following, a method of performing a deaeration operation in either the first kneading step or the second kneading step (Examples 1 and 2), a method of performing a deaeration operation in both steps (Example 3) In the process, a standard method in which no deaeration is performed (Comparative Example 1), a method of deaeration by ram-up kneading during the kneading (Comparative Example 2), a method of deaeration by additional kneading with a tandem mixer (Comparison) A rubber composition for cap tread rubber was produced using each of Example 3) and sheeted with a roll.

  Next, a vulcanizing agent was added to each rubber composition obtained in the second kneading step, kneaded (finishing step), sheeted, vulcanized, and the following rubber properties were measured.

2. Polymers and raw materials In the production of the rubber composition, the following types and blending amounts of polymers and raw materials were used. In addition, description of "PHR" in a compounding quantity shows the compounding quantity (mass part) with respect to 100 mass parts of polymer total amount.

(1) Type (a) Polymer As the polymer, NR, SBR (SBR whose terminal and main chain were modified with various modifiers), and BR were mixed and used. Specifically, it is as follows.

NR: TSR-20
SBR: Y031 (Asahi Kasei Co., Ltd., terminal-modified SBR, styrene content: 26% by mass)
BR: BR730 (manufactured by JSR, cis content: 95% by mass)

(B) Raw material Silica: “Ultrasil VN3” manufactured by Eponic Tegussa
Silane coupling agent: “NXT-Z45” manufactured by Momentive
Carbon black: “N134” manufactured by Philips
Aromatic oil: Idemitsu Kosan Co., Ltd., Diana Process AH-24
Zinc oxide: “Zinc oxide” manufactured by Mitsui Mining & Mining
Stearic acid: NOF Co., Ltd. stearic acid
Anti-aging agent: “Altigen 6C” manufactured by Sumitomo Chemical Co., Ltd.
Wax: “Sunknock N” manufactured by Ouchi Shinsei Chemical Co., Ltd.
Sulfur: Powdered sulfur vulcanization accelerator made by Karuizawa Sulfur Co., Ltd .: “Noxeller CZ” made by Ouchi Shinsei Chemical Co., Ltd.
Vulcanization accelerator: “Noxeller D” manufactured by Ouchi Shinsei Chemical Co., Ltd.

(2) Compounding amount (a) Polymer (total 100 PHR)
NR: 30 PHR
SBR: 40PHR
BR: 30 PHR

(B) Raw material Silica: 90 PHR
Silane coupling agent: 7.2 PHR
Carbon black: 10 PHR
Oil: 15 PHR
Zinc oxide, stearic acid, anti-aging agent, wax: appropriate amount sulfur + vulcanization accelerator: 4.5 PHR

3. Production of rubber composition (1) Comparative Example 1
(A) First kneading step All the amount of polymer (100 PHR), silica 60 PHR, silane coupling agent 4.8 PHR, carbon 10 PHR, and oil 15 PHR are charged into a Banbury mixer (filling rate 70%) and kneaded for 160 seconds. Then, the first kneaded product was discharged at a discharge temperature of 165 ° C. and sheeted with a roll.

(B) Second kneading step The entire amount of the first kneaded product, 30 PHR of silica, 2.4 PHR of silane coupling agent, stearic acid, wax, anti-aging agent, and zinc oxide are charged into a Banbury mixer (filling rate 70% ) After kneading for 120 seconds, the second kneaded product was discharged at a discharge temperature of 155 ° C. and sheeted with a roll.

(C) Third kneading step (finishing step)
The entire amount of the second kneaded product, sulfur + vulcanization accelerator 4.5 PHR was charged into the Banbury mixer (filling rate 70%), kneaded for 120 seconds, and then the third kneaded product was discharged at 100 ° C. The sheet was discharged and sheeted with a roll.

(2) Comparative Example 2
A rubber composition in the same manner as in Comparative Example 1 except that during the kneading in the first kneading step and the second kneading step, each kneading was performed while raming up for 30 seconds and degassing water vapor. Kneading was performed.

(3) Comparative Example 3
Comparative Example 1 except that in each of the first kneading step and the second kneading step, additional kneading using a tandem mixer provided with a steam degassing duct was performed while degassing the steam for 30 seconds. The rubber composition was kneaded in the same manner.

(4) Example 1
Kneading was performed in the same manner as in Comparative Example 1 except that the first kneading step was performed while degassing water vapor from the water vapor degassing duct provided in the chamber of the Banbury mixer (chamber control ON).

(5) Example 2
Kneading was performed in the same manner as in Comparative Example 1 except that the second kneading step was performed while degassing the water vapor from the vapor degassing duct provided in the chamber of the Banbury mixer (chamber control ON).

(6) Example 3
Similar to Comparative Example 1 except that each of the first kneading step and the second kneading step was performed while degassing the water vapor from the water vapor degassing duct provided in the chamber of the Banbury mixer (chamber control ON). And kneading.

4). Evaluation Evaluation was performed on the following items.

(1) Poor dough During sheeting in the second kneading step, the occurrence of sheet breakage was observed, and the evaluation was made according to three levels: “good”, “good”, and “not good”.

(2) Mooney viscosity and scorch time For the third kneaded product obtained in the third kneading step, Mooney viscosity (ML _{1 + 4} ) and scorch at 130 ° C. based on JIS K6301 using SMV300 manufactured by Shimadzu Corporation. Time (minutes) was measured.

(3) tan δ
The third kneaded product was vulcanized at a vulcanization temperature of 165 ° C. and a vulcanization time of 20 minutes to prepare a test sample, and tan δ at 70 ° C. was measured using an RPA measuring machine manufactured by Alpha Technology.

(4) Unreacted rate of silane coupling agent The second kneaded product obtained in the second kneading step is analyzed by gas chromatography to determine the amount of unreacted silane coupling agent, and the unreacted rate ( %) Was calculated.

(5) Silica dispersion The second kneaded product obtained in the second kneading step was analyzed by a microtome method to measure silica dispersion (%) in the rubber composition.

(6) Comprehensive determination Comprehensive determination was performed based on the evaluation results of (a) to (e) described above, and evaluation was performed in three stages: “good”, “acceptable”, and “impossible”.

5). Evaluation results The results of each evaluation are shown in Table 1.

  From Table 1, in Example 1 and Example 2 in which the chamber control was turned on in either the first kneading step or the second kneading step, the occurrence of defective fabrics was reduced compared to Comparative Example 1, It can be seen that the Mooney viscosity decreases and sufficient kneading is performed. And although scorch time is comparable as the comparative example 1, it turns out that tan-delta has fully reduced and rolling resistance has fallen effectively. Moreover, since the unreacted rate of a silane coupling agent is falling, it turns out that the silane reaction is fully performed and the dispersion | distribution of a silica is also improving.

  Furthermore, in Example 1 and Example 2, the same fabric defects and rubber properties as those of Comparative Examples 1 and 2 were obtained, and even without ram-up during kneading or additional kneading with a tandem mixer, It can be seen that the silane reaction can be promoted and silica can be dispersed. This result shows that kneading time can be shortened and more efficient kneading is possible.

  In Example 3 in which the chamber control was turned on in both the first kneading step and the second kneading step, the fabric defect did not occur, and the rubber characteristics were further improved. It turns out that it is preferable to turn it on.

  As mentioned above, although this invention was demonstrated based on embodiment, this invention is not limited to said embodiment. Various modifications can be made to the above-described embodiment within the same and equivalent scope as the present invention.

DESCRIPTION OF SYMBOLS 11 Banbury mixer 12 Stirring rotor 13 Kneading chamber 14 Discharge port 15 Kneading machine main body 16 Input port 17 Vertical hole 18 Lamb (floating weight)
19 Drop door

Claims (9)

A rubber composition for a tire in which silica and a silane coupling agent are blended in a polymer is kneaded by introducing the silica and the silane coupling agent in a kneading step using a hermetic rubber kneader. A method for producing a tire rubber composition to be produced, comprising:
In the kneading step, water produced by a silane reaction between the silica and the silane coupling agent is removed in the hermetic rubber kneader. The kneading step has a kneading step of two or more stages, and the silica and the silane coupling agent are added to each kneading step and kneaded,
The water generated by the silane reaction of the silica and the silane coupling agent in at least one kneading step among the two or more kneading steps is removed in the hermetic rubber kneader. The manufacturing method of the rubber composition for tires of Claim 1. The kneading step has a two-stage kneading step of a first kneading step and a second kneading step, and the silica and the silane coupling agent are mixed with the first kneading step and the second kneading step. It is divided into two stages of the kneading process, and kneaded.
The water generated by the silane reaction of the silica and the silane coupling agent in the first kneading step and / or the second kneading step is removed in the hermetic rubber kneader. Item 3. A method for producing a rubber composition for a tire according to Item 2. The polymer includes at least a polymer of natural rubber, styrene butadiene rubber, butadiene rubber,
The rubber composition for a tire is a rubber composition containing 30 to 120 parts by mass of the silica and 1 to 20 parts by mass of the silane coupling agent with respect to 100 parts by mass of the polymer. The manufacturing method of the rubber composition for tires of any one of Claim 1 thru | or 3. 5 to 70 parts by mass of a modified styrene butadiene rubber modified with a compound represented by the following formula (1) and having a bound styrene content of 21% by mass or less is contained in 100 parts by mass of the polymer. The manufacturing method of the rubber composition for tires of Claim 4.

In the formula, R ¹ , R ² and R ³ represent an alkyl group, an alkoxy group, a silyloxy group, an acetal group, a carboxyl group, a mercapto group or a derivative thereof, and R ⁴ and R ⁵ are a hydrogen atom or an alkyl group. Represents a group. N represents a positive integer.   The method for producing a rubber composition for a tire according to any one of claims 1 to 5, wherein the sealed rubber kneader is a Banbury mixer.   The tire according to claim 6, wherein a steam degassing duct with a filter is provided in a chamber of the Banbury mixer, and water generated by the silane reaction is removed by the water vapor degassing duct. For producing a rubber composition for use.   The method for producing a tire rubber composition according to any one of claims 1 to 7, wherein the tire rubber composition is a rubber composition for a tread rubber. Furthermore, a finishing step is provided in which a vulcanizing agent and a vulcanization accelerator are added to the kneaded product obtained in the kneading step and kneaded.
The method for producing a rubber composition for a tire according to any one of claims 1 to 8, wherein the kneaded product is kneaded until the temperature of the kneaded product becomes 90 to 120 ° C in the finishing step.

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