WO2018198630A1

WO2018198630A1 - Method for producing rubber composition and method for producing tire

Info

Publication number: WO2018198630A1
Application number: PCT/JP2018/012117
Authority: WO
Inventors: 太一永江; 村上　智洋
Original assignee: 東洋ゴム工業株式会社
Priority date: 2017-04-26
Filing date: 2018-03-26
Publication date: 2018-11-01
Also published as: JP6902389B2; JP2018184538A

Abstract

The method for producing a rubber composition according to the present invention comprises a first step, in which at least a rubber, silica, and a silane coupling agent are kneaded with a continuous kneader 5, and a second step, in which the mixture obtained in the first step is kneaded at a higher rubber temperature than in the first step to cause a coupling reaction to proceed.

Description

Rubber composition manufacturing method and tire manufacturing method

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

It is known that compounding agents such as silica and silane coupling agents are dispersed in rubber by a Banbury mixer which is a closed kneader. In this dispersion method, rubber and a compounding agent are put into a chamber of a Banbury mixer and kneaded.

However, in a Banbury mixer, if the rubber is subjected to high shear in order to disperse the silica well, the rubber temperature may rise excessively and the rubber may burn. This is because, in a Banbury mixer, the rubber temperature tends to rise and it is difficult to adjust the temperature.

JP 2005-1231 A Japanese Patent No. 5204610 JP 5567302 A

The method for producing a rubber composition in the present disclosure includes a step of kneading at least rubber, silica, and a silane coupling agent with a continuous kneader (hereinafter sometimes referred to as “first step”) and a first step. And a step of proceeding a coupling reaction by kneading the obtained mixture at a higher rubber temperature than the first step (hereinafter sometimes referred to as “second step”). The method for producing a tire in the present disclosure includes the method for producing a rubber composition in the present disclosure.

It is a schematic diagram which shows the continuous kneader used in Embodiment 1, a peripheral device, etc. FIG. The internal structure of the continuous kneader is shown.

Embodiment of this indication aims at providing the manufacturing method of a rubber composition which can improve silica dispersion.

The method for producing a rubber composition in the embodiment includes a first step in which at least rubber, silica and a silane coupling agent are kneaded with a continuous kneader, and a mixture produced in the first step is heated at a higher rubber temperature than in the first step. And a second step in which the coupling reaction is promoted by kneading.

The manufacturing method of the rubber composition in the embodiment can shear the rubber while suppressing the heat generation of the rubber, so that the silica dispersion can be increased before the coupling reaction proceeds. As a result, the rubber composition The silica dispersion of the product can be increased. The reason why the rubber can be sheared while suppressing the heat generation of the rubber lies in the use of a continuous kneader. Since the continuous kneader kneads while moving the rubber, the rubber can be cooled more efficiently than a closed kneader in which the rubber is kneaded in the chamber. Further, the continuous kneader can take a larger contact area between the rubber and the cooling surface than the closed kneader, and can cool the rubber efficiently.

The first step is preferably a step of kneading at a rubber temperature of less than 140 ° C. In the second step, the rubber temperature is preferably 140 ° C. or higher.

In the first step, it is preferable to knead in the first region of the continuous kneader, and in the second step, the mixture is preferably kneaded in the second region of the continuous kneader located downstream of the first region. . Instead, the mixture may be extruded in the first step.

The method for manufacturing a tire in the embodiment includes a first step and a second step.

Embodiment 1
From here, the present disclosure will be described in the first embodiment. First, the continuous kneader 5 will be described.

As shown in FIG. 1, the continuous kneader 5 includes a barrel 52. The barrel 52 includes

segments

521a, 521b, 521c, ..., 521g. Each of the

segments

521a, 521b, 521c,... 521g is provided with a cooling fluid flow path. The temperature of each of the

segments

521a, 521b, 521c, ..., 521g can be set independently. The temperature of each of the

segments

521a, 521b, 521c,..., 521g can be set by the

temperature controllers

61, 62, 63,. Examples of the cooling fluid include liquids such as oil and water. A raw material supply port 527 is provided in the segment 521a. The segment 521b is provided with a silane coupling agent inlet. The segment 521b is also provided with an oil inlet. The first region 522 of the barrel 52 is located upstream of the second region 523 of the barrel 52. The first region 522 includes

segments

521a, 521b, 521c, and 521d. The second region 523 is adjacent to the first region 522 downstream of the first region 522. The second region 523 includes

segments

521e, 521f, and 521g.

The continuous kneader 5 includes a screw 51. The screw 51 is located in the barrel 52. The screw 51 can be rotated by a motor 510. The screw 51 includes a screw shaft and

screw elements

511, 512, 513,. A flow path for cooling fluid is provided inside the screw shaft. Examples of the cooling fluid include liquids such as oil and water. Each

screw element

511, 512, 513,... 517 includes a screw blade. Each

screw element

511, 512, 513,... 517 has a through hole. A screw shaft is inserted into the through holes of the

screw elements

511, 512, 513,. The

screw elements

511, 512, 513,..., 517 can be separated from the screw shaft and can be recombined.

The method for producing a rubber composition in Embodiment 1 includes a step of kneading at least rubber, silica, and a silane coupling agent in the first region 522 with a continuous kneader 5. For example, rubber and a compounding agent such as silica, carbon black, stearic acid, wax, zinc oxide, anti-aging agent, silane coupling agent, and oil are supplied to the first region 522, and the rubber temperature is 140 ° C. in the first region 522. Kneading is carried out at a temperature lower than 130 ° C., preferably 130 ° C. or lower. The lower limit of the rubber temperature during kneading is, for example, 50 ° C. At this time, rubber, silica, carbon black, stearic acid, wax, zinc oxide, anti-aging agent and the like can be supplied from the raw material supply port 527 using a feeder, and the silane coupling agent is supplied from the injection pump 528. Can be supplied from the silane coupling agent inlet. Examples of the feeder include a belt type feeder, a screw type feeder, and a vibration type feeder. Oil can be supplied from an oil inlet using an injection pump 529. Examples of the rubber include natural rubber, isoprene rubber, polybutadiene rubber, styrene butadiene rubber, nitrile rubber, and chloroprene rubber. These can be used alone or in combination of two or more. Silica can be used alone or in combination of two or more. The amount of silica is preferably 10 parts by mass or more, more preferably 15 parts by mass or more with respect to 100 parts by mass of rubber. The upper limit of the amount of silica is, for example, 200 parts by mass with respect to 100 parts by mass of rubber. Examples of silane coupling agents include bis (3-triethoxysilylpropyl) tetrasulfide, bis (3-triethoxysilylpropyl) disulfide, bis (2-triethoxysilylethyl) tetrasulfide, bis (4-triethoxy). Sulfide silanes such as silylbutyl) disulfide, bis (3-trimethoxysilylpropyl) tetrasulfide, bis (2-trimethoxysilylethyl) disulfide, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, mercaptopropyl Mercaptosilanes such as methyldimethoxysilane, mercaptopropyldimethylmethoxysilane, mercaptoethyltriethoxysilane, 3-octanoylthio-1-propyltriethoxysilane, 3-pro Mention may be made of protected mercaptosilanes such as pionylthiopropyltrimethoxysilane. These can be used alone or in combination of two or more. The amount of the silane coupling agent is preferably 1 part by mass or more, more preferably 5 parts by mass or more with respect to 100 parts by mass of silica. The upper limit of the amount of the silane coupling agent is, for example, 20 parts by mass or 15 parts by mass with respect to 100 parts by mass of silica.

The step of proceeding the coupling reaction by kneading the mixture produced in the step of kneading in the first region 522 in the second region 523 at a higher rubber temperature than the step of kneading in the first region 522 is performed in the first embodiment. The manufacturing method of a rubber composition includes. In this step, for example, the mixture is kneaded at a rubber temperature of 140 ° C. or higher, preferably 150 ° C. or higher. The upper limit of the rubber temperature is, for example, 170 ° C.

The method for producing a rubber composition in Embodiment 1 further includes a step of kneading the vulcanizing compound into the pre-vulcanized compound compound rubber obtained in the step of promoting the coupling reaction to obtain a rubber composition. Examples of the vulcanizing compounding agent include vulcanizing agents such as sulfur and organic peroxides, vulcanization accelerators, vulcanization acceleration assistants, vulcanization retarders and the like. Examples of sulfur include powdered sulfur, precipitated sulfur, insoluble sulfur, and highly dispersible sulfur. Sulfenamide vulcanization accelerator, thiuram vulcanization accelerator, thiazole vulcanization accelerator, thiourea vulcanization accelerator, guanidine vulcanization accelerator, dithiocarbamate vulcanization accelerator as vulcanization accelerator And so on. In this step, a closed mixer, an open roll or the like can be used. Examples of hermetic mixers include Banbury mixers and kneaders.

The rubber composition contains rubber, silica, and a silane coupling agent. The rubber composition may further contain carbon black, stearic acid, wax, zinc oxide, anti-aging agent, oil, sulfur, vulcanization accelerator and the like.

The rubber composition can be used for tire members such as treads and sidewalls. Of these, tread is preferable.

The method for manufacturing a tire in Embodiment 1 includes a step of producing a green tire including a tire member including a rubber composition. The method for manufacturing a tire according to Embodiment 1 further includes a step of heating the raw tire. The tire obtained by the method of Embodiment 1 can be a pneumatic tire.

Modification 1 of Embodiment 1 will be described. Although the manufacturing method of the rubber composition in Embodiment 1 uses the continuous kneader 5 in which both the first region 522 and the second region 523 are provided, the modification 1 is the first region 522 of both. The first continuous kneader provided with only the first continuous kneader and the second continuous kneader provided only with the second region 523 are used. Specifically, the mixture is extruded with a first continuous kneader and the mixture is kneaded with a second continuous kneader.

Modification 2 of Embodiment 1 will be described. Although the manufacturing method of the rubber composition in the first embodiment uses the continuous kneader 5 in which both the first region 522 and the second region 523 are provided, the modified example 2 includes the first region 522 of both. A first continuous kneader provided only with a closed mixer and a closed mixer are used. Specifically, the mixture is extruded with a first continuous kneader, and the mixture is kneaded with a closed mixer.

Modification 3 of Embodiment 1 will be described. The manufacturing method of the rubber composition in Embodiment 1 includes a uniaxial continuous kneader 5 in both the step of kneading rubber, silica and a silane coupling agent and the step of proceeding the coupling reaction by kneading the mixture. However, the third modification uses a multi-axial continuous kneader instead of the continuous kneader 5. An example of the multi-axial continuous kneader includes a continuous kneader in which 12 co-rotating screws are arranged in a ring shape.

Hereinafter, examples of the present disclosure will be described.

Production of Vulcanized Rubber in Example 1 In the continuous kneader 5 shown in FIG. 1, all the segments in the first region 522 (

segments

521a, 521b, 521c, 521d) and all the segments in the second region 523 (

segment

521e, 521f, 521g) was set to the temperature control temperature shown in Table 1. Styrene butadiene rubber, polybutadiene rubber, silica, silane coupling agent (“Si75” manufactured by Degussa) and oil are supplied to the continuous kneader 5, kneaded in the first region 522 and the second region 523, and sulfur A rubber was obtained before addition. During the kneading, the rubber temperature was measured in the first region 522 and the second region 523. The rubber before sulfur addition, sulfur and a vulcanization accelerator were kneaded with a Banbury mixer to obtain an unvulcanized rubber. Unvulcanized rubber was vulcanized at 160 ° C. for 30 minutes to obtain a vulcanized rubber.

Production of Vulcanized Rubber in Comparative Example 1 Vulcanized rubber was produced in the same manner as in Example 1 except that a Banbury mixer was used instead of the continuous kneader 5. The discharge temperature of the rubber before sulfur addition was 155 ° C., and the kneading time until discharge was 7 minutes.

Production of Vulcanized Rubber in Comparative Example 2 Vulcanized rubber was produced in the same manner as in Example 1 except that the temperature control temperatures of the

segments

521a, 521b, 521c,.

Low heat generation performance The heat generation performance was evaluated based on the tan δ value of vulcanized rubber measured with a viscoelastic spectrometer manufactured by Toyo Seiki at an initial strain of 10%, dynamic strain of 2%, frequency of 50 Hz, and temperature of 60 ° C. The heat generation performance was shown by an index with the value of Comparative Example 1 being 100. The smaller the index, the better the low heat generation performance. The results are shown in Table 1.

Measurement of the Payne effect For vulcanized rubber, RPA2000 manufactured by Alpha Technologies is used, and the maximum shearing force is changed from the maximum shearing force when the strain is changed from 0.5% to 45% under the conditions of a temperature of 60 ° C and a frequency of 1.667 Hz. The value obtained by subtracting the force was measured, and the measurement result of each example was shown as an index with the measurement result of Comparative Example 1 as 100. A smaller index means better filler dispersibility. The results are shown in Table 1.

The vulcanized rubber of Example 1 was superior to the vulcanized rubber of Comparative Example 1 in silica dispersion and low heat generation performance. The vulcanized rubber of Example 1 was excellent in silica dispersion as compared with the vulcanized rubber of Comparative Example 2.

Claims

Kneading at least rubber, silica and silane coupling agent with a continuous kneader;
A step of proceeding a coupling reaction by kneading the mixture formed in the step at a rubber temperature higher than that in the step,
A method for producing a rubber composition.
The method for producing a rubber composition according to claim 1, wherein the step of kneading at least the rubber, the silica, and the silane coupling agent is a step of kneading at a rubber temperature of less than 140 ° C.
The method for producing a rubber composition according to claim 1 or 2, wherein the rubber temperature is 140 ° C or higher in the step of promoting the coupling reaction.
In the step of kneading at least the rubber, the silica and the silane coupling agent, kneading in the first region of the continuous kneader,
In the step of promoting the coupling reaction, the mixture is kneaded in a second region of the continuous kneader located downstream of the first region.
The method for producing a rubber composition according to any one of claims 1 to 3.
The method for producing a rubber composition according to any one of claims 1 to 3, wherein the mixture is extruded in the step of kneading at least the rubber, the silica, and the silane coupling agent.
A tire manufacturing method comprising the rubber composition manufacturing method according to any one of claims 1 to 5.