JP2017186485A - Method for manufacturing rubber composition for tire and method for manufacturing pneumatic tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a rubber composition for a tire capable of manufacturing a rubber composition excellent in abrasion resistance and reproducibility of operation stability, while suppressing problems such as roll adhesiveness, occurrence of air bubbles and rupture, at the time of warming.SOLUTION: A method for manufacturing a rubber composition for a tire includes: a kneading step 1 of kneading a rubber component, silica and a silane coupling agent without using a reaction accelerator of a silane coupling agent; and an extrusion step 2 of extruding the manufactured kneaded material while degassing.SELECTED DRAWING: None

Description

The present invention relates to a method for producing a tire rubber composition and a method for producing a pneumatic tire.

In recent years, low fuel consumption tires have attracted attention in consideration of environmental aspects. For example, rubber compositions in which silica or a silane coupling agent is blended with a rubber component are used. In general, a tire using silica as a filler has a smaller hysteresis loss than a tire using carbon black, and is advantageous in terms of fuel efficiency.

However, the silica compound is added to terminate the adhesion of the roll during heating, the generation and rupture of bubbles due to the unreacted portion of the silane coupling agent during cold extrusion, and the reaction of the silane coupling agent. There are problems such as deterioration of wear resistance and strength characteristics due to non-dispersion of reaction accelerators such as borate, and deterioration in reproducibility of steering stability due to large variation in the performance of the manufactured tires. .

Patent Document 1 discloses a tread rubber composition excellent in rolling resistance and workability containing a predetermined rubber component and filler. However, roll adhesion during heating, generation and bursting of bubbles, wear resistance, There is still room for improvement in regard to the deterioration of strength characteristics and the improvement of reproducibility of steering stability.

JP 2005-126556 A

The present invention can solve the above-mentioned problems, and can produce a rubber composition excellent in wear resistance, reproducibility of steering stability, etc. while suppressing problems of roll adhesion, bubble formation and bursting during heating. Another object of the present invention is to provide a method for producing a tire rubber composition.

The present invention includes a kneading step 1 for kneading a rubber component, silica and a silane coupling agent without using a reaction accelerator for a silane coupling agent, and an extrusion step 2 for extruding the prepared kneaded material while degassing. The manufacturing method of the rubber composition for tires containing these.

In the production method, the content of styrene butadiene rubber in 100% by mass of the rubber component is 50% by mass or more, the content of silica is 30 parts by mass or more relative to 100 parts by mass of the rubber component, and the silane coupling agent is based on 100 parts by mass of silica. A method for producing a rubber composition having a content of 4 parts by mass or more is preferred.

The present invention also relates to a method for manufacturing a pneumatic tire including a step of manufacturing a tire member using the rubber composition obtained by the manufacturing method.

The method for producing a tire rubber composition of the present invention comprises a kneading step 1 for kneading a rubber component, silica and a silane coupling agent without using a reaction accelerator for a silane coupling agent, and the kneaded product thus produced. , And extruding process 2 that extrudes while degassing, so that it is excellent in wear resistance, reproducibility of steering stability, etc. while suppressing problems of roll adhesion, bubble formation and bursting during heating It is possible to produce a rubber composition for a tire.

It is an example of the schematic of an extrusion apparatus.

The present invention includes a kneading step 1 for kneading a rubber component, silica and a silane coupling agent without using a reaction accelerator for a silane coupling agent, and an extrusion step 2 for extruding the prepared kneaded material while degassing. The manufacturing method of the rubber composition for tires containing these.

As described above, in general, silica blending has problems such as roll adhesion at the time of heating, generation and rupture of bubbles, deterioration of wear resistance and strength characteristics, deterioration of reproducibility of steering stability, etc. Since the production method is a method of kneading without adding a reaction accelerator such as tetraborate during the kneading step 1, there is no decrease in wear resistance and strength characteristics due to the addition of the reaction accelerator. The rubber composition can be provided with excellent wear resistance and strength characteristics. Furthermore, following the kneading step 1, by carrying out the kneaded product extruding step 2 while degassing, there is a problem of generation of bubbles and bursting due to roll adhesion during heating and unreacted silane coupling agent during extrusion. Can also be prevented. In addition, the reproducibility (repeatability) of steering stability of the actual vehicle is improved, and a tire with excellent performance uniformity can be provided. Therefore, according to the production method of the present invention, a rubber composition for tires excellent in wear resistance, reproducibility of steering stability, and the like is produced while suppressing problems of roll adhesion at the time of heating, generation of bubbles and bursting. It becomes possible to do.

<Kneading process 1>
In the kneading step 1, the rubber component, silica, and silane coupling agent are kneaded, and the kneading is performed without adding a reaction accelerator for the silane coupling agent.

The kneading step of the rubber composition generally includes a base kneading step for kneading chemicals other than the vulcanizing agent and the vulcanization accelerator, and a vulcanizing agent and a vulcanization accelerator in the mixture obtained in the base kneading step. And a finishing kneading step of adding and kneading. And in this invention, the kneading | mixing process 1 of a base kneading process and a finishing kneading process is performed, without using the reaction promoter of a silane coupling agent.

(Base kneading process)
The kneading in the base kneading step is not particularly limited, and can be carried out using a general rubber industry kneader such as a Banbury mixer or an open roll.

The kneading temperature in the base kneading step is preferably 80 ° C. or higher, more preferably 140 ° C. or higher, and preferably 200 ° C. or lower, more preferably 180 ° C. or lower. If the kneading temperature is too low, the reaction between the silane coupling agent and silica does not proceed sufficiently, and the silica tends not to be uniformly dispersed. On the other hand, if the kneading temperature is too high, the Mooney viscosity increases and the processability tends to deteriorate.

The kneading time in the base kneading step is not particularly limited, but is usually 30 seconds or longer, preferably 1 to 30 minutes.

As a base kneading | mixing process, the process of kneading | mixing a rubber component, a silica, and a silane coupling agent is performed, for example, without using the reaction promoter of a silane coupling agent.

In the base kneading step, carbon black, oil, stearic acid, wax, anti-aging agent, zinc oxide and the like may be kneaded in addition to the rubber component, silica and silane coupling agent. In the base kneading step, all of the above components may be kneaded in one step, but all or a part of each component may be kneaded in each step by dividing into two or more base kneading steps.

Inorganic potassium salts such as potassium tetraborate, potassium carbonate, potassium hydrogen carbonate, potassium sulfate, potassium hydrogen phosphate, potassium dihydrogen phosphate, potassium oxalate are used as reaction accelerators for silane coupling agents not added in kneading step 1 , Etc.

As rubber components, natural rubber (NR), isoprene rubber (IR), butadiene rubber (BR), styrene butadiene rubber (SBR), styrene isoprene butadiene rubber (SIBR), ethylene propylene diene rubber (EPDM), chloroprene rubber (CR ) And diene rubbers such as acrylonitrile butadiene rubber (NBR). Of these, SBR, NR, and BR are preferable, and SBR and NR are more preferable.

Examples of SBR include emulsion polymerization SBR (S-SBR), solution polymerization SBR (E-SBR), etc. Among them, S-SBR is preferable. As S-SBR, high molecular weight S-SBR that has been made high in molecular weight by coupling with Sn or Si, high molecular weight modified S-SBR that has been terminal-modified so as to react with silica, and the like can be used. Here, the coupling method can be carried out by reacting an alkali metal (such as Li) or an alkaline earth metal (such as Mg) at the molecular chain end of S-SBR with tin halide, silicon halide or the like.

As NR, SIR20, RSS # 3, TSR20, etc., and as BR, those commonly used in the tire industry such as high cis BR, high transformer BR, etc. can be used.

The blending ratio of the rubber component in the kneading step 1 (base kneading step) is preferably 80% by mass or more, more preferably 90% by mass or more, and still more preferably, in 100% by mass of all rubber components used for the production of the rubber composition Is 100% by mass. Thereby, a coupling reaction advances effectively.

Examples of the silica include silica produced by a wet method, silica produced by a dry method, and the like, but there is no particular limitation.

The nitrogen adsorption specific surface area (N ₂ SA) of silica is preferably 80 m ² / g or more, more preferably 120 m ² / g or more. If it is less than 80 m ² / g, there is a possibility that sufficient reinforcing properties cannot be obtained. Further, N ₂ SA of silica is preferably 250 m ² / g or less, more preferably 200 m ² / g or less. When it exceeds 250 m ² / g, the workability tends to deteriorate.
The _N 2 SA of silica is a value measured by the BET method in accordance with ASTM D3037-81.

In 100% by mass of the total silica used for the production of the rubber composition, the mixing ratio of silica in the kneading step 1 (base kneading step) is preferably 80% by mass or more, more preferably 90% by mass or more, and further preferably 100%. % By mass. Thereby, a coupling reaction advances effectively.

Examples of the silane coupling agent include sulfide-based silane couplings such as bis (3-triethoxysilylpropyl) tetrasulfide, bis (3-triethoxysilylpropyl) trisulfide, and bis (3-triethoxysilylpropyl) disulfide. An agent, etc. can be used conveniently.

The blending ratio of the silane coupling agent in the kneading step 1 (base kneading step) is preferably 80% by mass or more, more preferably 90% by mass in 100% by mass of the total silane coupling agent used for the production of the rubber composition. As mentioned above, More preferably, it is 100 mass%. Thereby, a coupling reaction advances effectively.

Examples of carbon black include GPF, FEF, HAF, ISAF, and SAF, but are not particularly limited.

The nitrogen adsorption specific surface area (N ₂ SA) of carbon black is preferably 30 m ² / g or more, more preferably 70 m ² / g or more. If it 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, and more preferably not more than 200m ² / g. When it exceeds 250 m ² / g, the workability tends to deteriorate.
The N ₂ SA of carbon black is determined by the A method of JIS K6217.

The oil is not particularly limited, and those common in the tire industry can be used. Examples thereof include process oils such as aroma oil, mineral oil, and naphthenic oil, and vegetable oils such as castor oil. Of these, process oil is preferred.

In addition, regarding carbon black and oil, it is preferable that the blending ratio of the kneading step 1 (base kneading step) is the same as the above in the total amount used for the production of the rubber composition.

(Finish kneading process)
In the finishing kneading process, for example, after cooling the mixture obtained in the base kneading process, the mixture obtained in the base kneading process is added without using a silane coupling agent reaction accelerator, as in the base kneading process. A kneaded product is produced by kneading a vulcanizing agent and a vulcanization accelerator. For the kneading in the finishing kneading step, the same method as in the base kneading step can be used. In addition, the temperature which cools the mixture obtained at the base kneading | mixing process is 100 degrees C or less normally, Preferably it is 20-80 degreeC.

The kneading temperature in the finishing kneading step is preferably 110 ° C. or lower, more preferably 100 ° C. or lower. When it exceeds 110 degreeC, there exists a possibility that rubber | gum burning (scorch) may arise. Although the minimum of kneading | mixing temperature is not specifically limited, Preferably it is 70 degreeC or more, More preferably, it is 90 degreeC or more.

The kneading time in the finishing kneading step is not particularly limited, but is usually 30 seconds or longer, preferably 1 to 30 minutes.

In the final kneading step, materials other than the mixture, vulcanizing agent, and vulcanization accelerator may be appropriately kneaded as long as the effects of the present invention are not impaired. In the finishing kneading step, all of these components may be kneaded in one step, but all or part of each component may be kneaded in each step by dividing into two or more finishing kneading steps.

It is preferable to use sulfur as a vulcanizing agent. It does not specifically limit as sulfur, A thing common in a tire industry can be used. Moreover, what is generally used in the tire industry can also be used as a vulcanization accelerator.

<Extrusion process 2>
In the extrusion step 2, the kneaded material produced in the kneading step 1 (the finishing kneading step) is extruded and degassed. As a result, air generated in the kneaded product and gas generated by the reaction in the rubber are removed, and generation and bursting of bubbles can be prevented. In addition, by performing the extrusion process 2 together with the kneading process 1, it is possible to prevent roll adhesion during hot-heating. Furthermore, the kneading step 1 is carried out without using the reaction accelerator, and the reaction between the silica and the silane coupling agent proceeds by vacuuming without including the reaction accelerator in the extrusion step 2, resulting in the reaction accelerator. As a result, it is possible to manufacture a tire excellent in performance such as wear resistance, strength characteristics, and reproducibility of steering stability.

In the extrusion process 2, air or gas can be degassed from the kneaded product by using an extrusion apparatus capable of degassing (vacuum). Deaeration may be performed during the entire extrusion process (extrusion molding) or a part of the process. As an extrusion apparatus, a screw extruder equipped with a deaeration means can be used. Deaeration can be performed with a vacuum pump, an aspirator, or the like.

For example, extrusion molding can be carried out while degassing the kneaded product using the apparatus shown in FIG.
FIG. 1 is an example of a schematic view of an extrusion apparatus.
A rubber molding apparatus 1 (screw extrusion apparatus) in FIG. 1 includes a screw extruder 11 provided with a deaeration means for kneading and transporting a charged kneaded material, and a sheet rubber extruder 21. A screw-type extruder (also referred to as “extruder with a degassing port”) 11 includes a degassing port 12 for degassing air in the kneaded product and a gas generated by a reaction, and the sheet rubber extruder 21 includes a gear pump. 22 and a base 23, and a feed rubber produced by an extruder 11 with a degassing port is formed into a sheet rubber.

The extruder 11 with the deaeration port preferably has a plurality of stages of screws as a means for transferring the added kneaded material, and FIG. 1 shows a two-stage screw including the first and second screw portions 11a and 11b. . The first and second screw parts 11a and 11b have screw leads of the second screw part 11b for transferring the feed rubber after deaeration so that air does not enter the rubber deaerated by the vacuum part 13. It is adjusted to be larger than the lead of the screw of the first screw part 11a before degassing, and thereby the rubber is instantaneously supplied to the gear pump 22.

A barrel (casing) 14 containing the first and second screw parts 11a and 11b has a hopper 15 for charging the kneaded material, and a screw head part for discharging the feed rubber kneaded on the opposite side of the hopper 15 16 (discharge unit) is provided.

Between the first screw part 11a and the second screw part 11b, the feed rubber discharged from the first screw part 11a is taken up by the second screw part 11b and further transferred to the screw head part 16 A vacuum unit 13 that also serves as a relay unit is provided. A degassing port 12 is provided in the barrel 14 around the vacuum unit 13. The deaeration port 12 is connected to an exhaust passage 17 communicating with the peripheral surface of the barrel 14 communicating with a vacuum pump (not shown), for example, and constitutes deaeration means.

The kneaded material thrown in from the hopper 15 is transferred to the vacuum unit 13 while being kneaded by the first screw portion 11a, and the moisture evaporated from the feed rubber, the air taken into the inside, and the gas generated during the kneading are removed. The air is sucked and discharged from the vacuum port 13 (details are not shown) by the air vent 12, and the air in the feed rubber can be reduced.

The sheet rubber extruder 21 includes a casing 24 that accommodates the gear pump 22, an intake port 25 for receiving the feed rubber kneaded and transferred by the extruder 11 with the degassing port, and a head unit 26. A base 23 for extruding the sheet rubber is integrally attached to the.

The kneaded material put into the hopper 15 by the apparatus shown in FIG. 1 is transferred toward the screw head portion 16 which is a discharge portion while being kneaded by the screw extruder 11. The air taken in and the generated gas are sucked and discharged to the outside through the deaeration port 12. Then, the feed rubber introduced into the gear pump 22 from the intake port 25 provided in the casing 24 of the directly connected sheet rubber extruder 21 is the sheet rubber formed from the base 23 of the head portion 26 by the gear pump 22. Discharged.

In addition, since the deaeration process is performed in the extrusion step 2, it is possible to prevent roll adhesion when heat is applied with an open roll or the like.

<Vulcanization process>
The unvulcanized rubber composition produced in the extrusion step 2 is molded by a known method and then vulcanized to obtain the tire rubber composition of the present invention. The vulcanization temperature is preferably 140 ° C. or higher, more preferably 150 ° C. or higher, and preferably 180 ° C. or lower, more preferably 170 ° C. or lower, from the viewpoint that the effects of the present invention can be obtained satisfactorily. The vulcanization time is preferably 5 to 30 minutes from the viewpoint that the effects of the present invention can be obtained satisfactorily.

<Rubber composition for tire>
In the tire rubber composition produced by the above production method, the content of SBR in 100% by mass of the rubber component is preferably 50% by mass or more, more preferably 60% by mass or more. If it is less than 50% by mass, grip performance and wear resistance may be lowered. Moreover, this content becomes like this. Preferably it is 90 mass% or less, More preferably, it is 80 mass% or less. When it exceeds 90 mass%, there is a tendency that good durability cannot be obtained.

In the tire rubber composition produced by the above production method, the content of NR in 100% by mass of the rubber component is preferably 40% by mass or less, more preferably 30% by mass or less, and further preferably 20% by mass or less. is there. If it exceeds 40% by mass, grip performance and wear resistance may be reduced. The lower limit in the case of blending NR is preferably 10% by mass or more, more preferably 20% by mass or more, and further preferably 25% by mass or more. If it is less than 10% by mass, good durability tends not to be obtained.

In the tire rubber composition produced by the above production method, the BR content in 100% by mass of the rubber component is preferably 40% by mass or less, more preferably 30% by mass or less, and further preferably 20% by mass or less. is there. If it exceeds 40% by mass, grip performance tends to deteriorate. The lower limit when blending BR is preferably 10% by mass or more, more preferably 20% by mass or more, and still more preferably 25% by mass or more. When it is less than 10% by mass, good wear resistance tends to be not obtained.

In the rubber composition for tires produced by the production method, the content of silica is preferably 30 parts by mass or more, and more preferably 40 parts by mass or more with respect to 100 parts by mass of the rubber component. If the amount is less than 30 parts by mass, sufficient fuel economy may not be obtained. The content is preferably 100 parts by mass or less, more preferably 80 parts by mass or less. When the amount exceeds 100 parts by mass, there is a possibility that roll adhesion or fabric failure may occur.

In the rubber composition for tires produced by the above production method, the content of the silane coupling agent is preferably 4 parts by mass or more, more preferably 6 parts by mass or more with respect to 100 parts by mass of silica. If it is less than 4 parts by mass, fuel economy may not be obtained. The content is preferably 15 parts by mass or less, more preferably 10 parts by mass or less. When it exceeds 15 parts by mass, there is a tendency that an effect commensurate with the increase in cost cannot be obtained.

In the tire rubber composition produced by the above production method, the content of carbon black is preferably 5 parts by mass or more, more preferably 15 parts by mass or more with respect to 100 parts by mass of the rubber component. If the amount is less than 5 parts by mass, sufficient reinforcing properties tend not to be obtained. The content is preferably 40 parts by mass or less, more preferably 30 parts by mass or less. When it exceeds 40 mass parts, there exists a tendency for rolling resistance to become large.

In the tire rubber composition produced by the above production method, the total content of silica and carbon black is preferably 40 parts by mass or more, more preferably 50 parts by mass or more with respect to 100 parts by mass of the rubber component. If the amount is less than 40 parts by mass, sufficient reinforcing properties may not be obtained. The total content is preferably 120 parts by mass or less, more preferably 100 parts by mass or less. When it exceeds 120 parts by mass, rolling resistance tends to increase.

In the tire rubber composition produced by the above production method, the oil content is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, with respect to 100 parts by mass of the rubber component. If it is less than 5 parts by mass, the fabric of the unvulcanized rubber composition tends to deteriorate. The content is preferably 40 parts by mass or less, more preferably 25 parts by mass or less. When it exceeds 40 parts by mass, the tackiness of the unvulcanized rubber composition is too strong and the processability tends to deteriorate. In addition, the wear resistance and fuel efficiency may be impaired.

In the rubber composition for tires produced by the manufacturing method, the sulfur content is preferably 0.8 parts by mass or more, more preferably 1.0 parts by mass or more, with respect to 100 parts by mass of the rubber component. If it is less than 0.8 part by mass, the vulcanization reaction may be insufficient. The content is preferably 2.0 parts by mass or less, more preferably 1.7 parts by mass or less. If it exceeds 2.0 parts by mass, the heat resistance may decrease.

The rubber composition for tires can be used for each member of a tire, and in particular, can be suitably applied to a tread.

The pneumatic tire can be produced by a production method including a step of producing a tire member using the rubber composition obtained by the production method. For example, the unvulcanized rubber composition produced by the above production method is extruded according to the shape of each member of a tire such as a tread, and is molded by a normal method on a tire molding machine, and then an unvulcanized tire Can be produced by heating and pressing in a vulcanizer.

The present invention will be specifically described based on examples, but the present invention is not limited to these examples.

Hereinafter, various chemicals used in Examples and Comparative Examples will be described.
NR: SIR20
S-SBR: SE-2148 manufactured by Sumitomo Chemical Co., Ltd.
Carbon black: Diamond Black I (N ₂ SA: 114 m ² / g) manufactured by Mitsubishi Chemical Corporation
Silica: Ultrasil VN3 manufactured by Evonik Degussa (N ₂ SA: 175 m ² / g)
Silane coupling agent: Si266 (bis (3-triethoxysilylpropyl) disulfide) manufactured by Evonik Degussa
Process oil: NH70S made by Idemitsu Kosan Co., Ltd.
Wax: Ozoace 0355 manufactured by Nippon Seiki Co., Ltd.
Anti-aging agent: Santoflex (N- (1,3-dimethylbutyl) -N′-phenyl-p-phenylenediamine (6PPD)) manufactured by Flexis Co., Ltd.
Processing aid: Zirl &Zylaher's Structol EF44
Stearic acid: Stearic acid “椿” manufactured by NOF Corporation
Zinc oxide: 2 types of zinc oxide manufactured by Mitsui Mining & Smelting Co., Ltd. Powder sulfur: 5% oil-treated powder sulfur vulcanization accelerator manufactured by Tsurumi Chemical Mining Co., Ltd. A: Soxinol DG manufactured by Sumitomo Chemical Co., Ltd.
Vulcanization accelerator B: CBS made by KEMAI Acc
Reaction accelerator: Yoneyama Chemical potassium tetraborate (50 mesh)

(Examples and Comparative Examples)
According to the formulation shown in Table 1, chemicals other than sulfur and a vulcanization accelerator were kneaded for 3 minutes at 160 ° C. using a Banbury mixer. Furthermore, sulfur and a vulcanization accelerator were added, and kneaded for 5 minutes using an open roll at 100 ° C. to obtain a kneaded product (kneading step 1).
The kneaded product was extruded using the extrusion apparatus shown in FIG. 1 under the conditions shown in Table 1 (with or without vacuum treatment) and the following conditions to produce an unvulcanized rubber sheet (extrusion step 2).
The resulting unvulcanized rubber sheet is molded into a tread shape, and bonded together with other tire members on a tire molding machine to form an unvulcanized tire, and press vulcanized for 40 minutes at 150 ° C., A test tire (size: 215 / 45R17) was produced (vulcanization step).

(Extrusion conditions)
Deaeration means: vacuum pump (vacuum degree: 133 Pa or less)
Extrusion speed: 20m / min
Molded sheet thickness: 2.0 mm
Extrusion temperature: 130 ° C

The following methods were used to evaluate the roll adhesion during heating, the occurrence of bubbles and rupture during the extrusion process, the wear resistance of the test tire, and the reproducibility of steering stability. The results are shown in Table 1. .

(Roll adhesion)
The roll adhesion was evaluated depending on whether or not the kneaded material was in close contact with the roll during hot-heating.
○: Adhesion did not occur.
X: Adhesion occurred.

(Bubble generation / rupture)
Reaction completeness was evaluated by whether or not bubbles or rupture occurred during the extrusion process.
○: No bubbles or rupture occurred.
Δ: Bubbles or rupture occurred.
X: Many bubbles and ruptures occurred.

(Abrasion resistance)
Each test tire was mounted on a domestic FF vehicle, the groove depth of the tire tread portion after a running distance of 8000 km was measured, the running distance when the tire groove depth decreased by 1 mm was calculated, and indexed by the following formula. The higher the index, the better the wear resistance.
(Abrasion resistance index) = (travel distance when the 1 mm groove depth decreases) / (travel distance when the tire groove of Example 1 decreases by 1 mm) × 100

(Reproducibility of steering stability)
Ten test tires for each example and comparative example were prepared, each mounted on a domestic FF vehicle, and the steering stability of the dry road surface (high speed lane changeability in a speed range up to 240 km / h) was sensory evaluated. The variation in performance was evaluated. The variation in Example 1 was taken as 100 and indexed. The larger the index, the less the variation in steering stability (high-speed lane changeability) and the better the stability of steering stability.

From Table 1, Example 1 in which the reaction accelerator was not added in the finishing kneading process and the vacuum treatment was performed in the extrusion process 2 prevented roll adhesion, air bubbles and rupture, and the tire wear resistance and steering stability. Excellent reproducibility.

On the other hand, Comparative Examples 1 and 2 to which a reaction accelerator was added were inferior in the reproducibility of wear resistance and steering stability, and Comparative Example 3 in which no reaction accelerator was added and no vacuum treatment was performed was further in close contact with the roll. It was inferior in nature.

1 Rubber molding equipment 11 Screw extruder (extruder with degassing port)
11a 1st screw part 11b 2nd screw part 12 Deaeration port 13 Vacuum part 14 Barrel (casing)
15 Hopper 16 Screw head (discharge unit)
17 Exhaust passage 21 Sheet rubber extruder 22 Gear pump 23 Base 24 Casing 25 Intake port 26 Head

Claims (3)

Kneading step 1 for kneading the rubber component, silica and silane coupling agent without using a reaction accelerator for the silane coupling agent;
The manufacturing method of the rubber composition for tires including the extrusion process 2 which extrudes the produced kneaded material, deaerating. The content of styrene butadiene rubber in 100% by mass of the rubber component is 50% by mass or more,
The content of silica with respect to 100 parts by mass of the rubber component is 30 parts by mass or more,
The manufacturing method of the rubber composition for tires of Claim 1 which manufactures the rubber composition whose content of the silane coupling agent with respect to 100 mass parts of silicas is 4 mass parts or more. The manufacturing method of a pneumatic tire including the process of producing a tire member using the rubber composition obtained by the manufacturing method of Claim 1 or 2.

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