JP2011021108A - Method for producing wet master batch, rubber composition obtained by using the wet master batch, and pneumatic tire obtained by using the rubber composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a wet master batch having excellent dispersibility of carbon black and uniform dispersibility, and to provide a rubber composition obtained by using the wet master batch. <P>SOLUTION: The method for producing a wet master batch comprises mixing a carbon black-containing slurry solution and a rubber latex solution in a liquid phase and drying the mixture, wherein a coagulation step where a mixture solution containing the carbon black-containing slurry solution and the rubber latex solution is fed to a tank and a high-pressure air flow is jetted to the mixture solution to induce a turbulent flow in the tank, and thereby to generate a coagulated product from the mixture solution, and a pulverization step where a high-pressure air flow is jetted to the coagulated product to pulverize the product, are simultaneously carried out. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method for producing a wet masterbatch in which a carbon black-containing slurry solution and a rubber latex solution are mixed in a liquid phase and dried, a rubber composition obtained using the wet masterbatch, and the rubber composition The present invention relates to a pneumatic tire obtained using an object.

  Conventionally, in the rubber industry, it is known to use a wet masterbatch in order to improve processability and dispersibility of a filler when producing a rubber composition containing a filler such as carbon black. . This is because a filler and a dispersion solvent are mixed in advance at a certain ratio, and a filler-containing slurry solution in which the filler is dispersed in the dispersion solvent by mechanical force, and a rubber latex solution are mixed in a liquid phase. Then, a solidified product obtained by adding a coagulant such as an acid is recovered and dried. When using a wet masterbatch, the dispersibility of the filler is superior compared to when using a dry masterbatch obtained by mixing the filler and rubber in a solid phase, and rubber properties such as workability and reinforcement A rubber composition having excellent resistance is obtained. By using such a rubber composition as a raw material, for example, rubber products such as tires having reduced rolling resistance and excellent fatigue resistance and wear resistance can be manufactured.

  The manufacturing method of the wet master batch mentioned above is described, for example in the following patent documents 1-2. However, in the methods described in these patent documents, the filler-containing slurry solution and the rubber latex solution are mixed by mechanical force (mechanical stirring), so that the coagulum remains in the stirring part and the solidifying part. The wet master batch recovery rate tended to decrease. In addition, there was a tendency for residual coagulum to be mixed into the next batch, resulting in non-uniform coagulum being produced.

  Patent Document 3 below describes a method of mixing a filler-containing slurry solution and a rubber latex solution by high-speed flow. However, since the solidification part of the manufacturing apparatus used in such a method has a configuration in which a plurality of cylinders are simply connected, there is a tendency for the solidified matter to remain in the cylinders. Further, when the inside of the coagulation part is heated in order to promote the coagulation of the mixture of the filler-containing slurry solution and the rubber latex solution, the coagulum grows in the cylinder, and as a result, the high-speed flow is hindered and mixing is prevented. When it became insufficient, there was a tendency for non-uniform solidified products to be formed.

  Further, Patent Document 4 below describes a method of mixing a filler-containing slurry solution and a rubber latex solution by a steam jet. However, in such a method, it is only described that the filler-containing slurry solution and the rubber latex solution are simply stirred and mixed with water vapor, and in order to solidify the mixed solution, a coagulant is separately added and stirred. The actual situation was mechanical stirring with a blade or the like.

JP 2007-237456 A Republished patent WO2005 / 12396 JP 2000-507892 A JP-A-36-22729

  The present invention has been made in view of the above circumstances, and its object is to produce a wet masterbatch having excellent dispersibility of carbon black and uniform dispersibility, and a rubber obtained using the wet masterbatch. It is in providing the composition and the pneumatic tire obtained using this rubber composition.

  The above object can be achieved by the present invention as described below. That is, the method for producing a wet masterbatch according to the present invention is a method for producing a wet masterbatch in which a carbon black-containing slurry solution and a rubber latex solution are mixed in a liquid phase and dried. A coagulation step of generating a coagulum from the mixed solution by charging a mixed solution containing the slurry solution containing the rubber latex solution and injecting a high-pressure airflow into the mixed solution to cause turbulence in the tank; And a crushing step of crushing the coagulated product by injecting the high-pressure airflow onto the coagulated product.

  As described above, the method for producing a wet masterbatch according to the present invention is characterized by coagulating the carbon black-containing slurry solution and the rubber latex solution (coagulation step) and simultaneously crushing the coagulated product (crushing step). And More specifically, by injecting a high-pressure air flow into the mixed solution in the tank and causing the turbulent flow of the mixed solution in the tank, a physical shearing force due to the turbulent flow is applied to the mixed solution. And a solidified product is generated by this shearing force (coagulation step). Due to the shearing force caused by the turbulent flow, this coagulum is generated in the same tank and simultaneously crushed (crushing step). As a result, in the method for producing a wet masterbatch according to the present invention, carbon black is excellent in dispersibility, and a uniform solidified product and a crushed product thereof are obtained. And a wet masterbatch having uniform dispersibility can be produced. In the method for producing a wet masterbatch according to the present invention, the carbon black-containing slurry solution and the rubber latex solution are sufficiently mixed by the physical shearing force resulting from the turbulent flow in the coagulation step. That is, since the mixing process, the coagulation process, and the crushing process can be performed simultaneously in the same tank, the process is simplified and the productivity is very excellent.

  In the wet masterbatch manufacturing method, the solidification step introduces the carbon black-containing slurry solution into a tank, and injects a high-pressure air flow into the carbon black-containing slurry solution, thereby causing turbulence in the tank. It is preferable that the rubber latex solution is charged in a state where the coagulated product is generated from the mixed solution. According to such a method for producing a wet masterbatch, the rubber latex solution is solidified by physical shearing force due to turbulent flow before being sufficiently mixed with the carbon black-containing slurry solution. It can prevent more reliably that it becomes a lump. As a result, the dispersibility of carbon black is further improved, and a more uniform solidified product and its crushed material can be obtained. By using this as a raw material, the dispersibility of carbon black is further improved and the dispersibility is more uniform. Can be produced. In addition, it is possible to more reliably prevent the coagulated material from forming a lump like a rubber ball, so that the coagulated material and its crushed material can be easily dehydrated and dried in the subsequent process, further improving the productivity of the wet masterbatch. To do.

  In the wet masterbatch production method, it is preferable to use compressed air or high-pressure steam as the high-pressure airflow. According to such a wet masterbatch manufacturing method, the turbulent flow of the mixed solution can be caused more reliably and easily in the tank.

  In the method for manufacturing the wet masterbatch, it is preferable that a flow rate at the time of jetting the high-pressure air flow is 20 m / s to 120 m / s. If the flow velocity during jetting of the high-pressure air flow is less than 20 m / s, even if the high-pressure air flow is jetted into the mixed solution in the tank, the turbulent flow of the mixed solution may not be sufficiently caused. In some cases, the dispersibility of the coagulated product is deteriorated and the coagulated product is not sufficiently crushed so that the coagulated product becomes a lump like a rubber ball. On the other hand, when the flow velocity at the time of jetting the high-pressure air flow exceeds 120 m / s, the mixed solution may be scattered in the tank, so that the turbulent flow of the mixed solution may not be caused sufficiently. In addition, the inner wall of the tank is ground over time with a high-pressure airflow, and foreign matter (contamination) resulting from the grinding dust may be mixed into the solidified product.

  In the wet masterbatch manufacturing method, the temperature of the mixed solution after the high-pressure airflow injection is preferably 10 to 120 ° C. If the temperature of the mixed solution after the high-pressure airflow injection is less than 10 ° C., the mixed solution may not sufficiently solidify even when the high-pressure airflow is injected into the mixed solution. May decrease. On the other hand, when the temperature of the mixed solution after high-pressure airflow injection exceeds 120 ° C., the mixed solution boils and a coagulated product is locally generated, which may deteriorate the dispersibility of the coagulated product.

  In the method for producing the wet master batch, it is preferable that the pH of the mixed solution is adjusted to 3 to 4 by further adding an acid or a metal salt as a coagulant to the mixed solution. According to such a method for producing a wet masterbatch, combined with a physical shearing force due to turbulent flow, the mixed solution solidifies more rapidly and the dispersibility of the solidified product is further improved.

  The rubber composition according to the present invention is obtained by using a wet masterbatch produced by any one of the methods described above. As described above, the wet masterbatch produced by the production method of the present invention has excellent dispersibility of carbon black and uniform dispersibility. As a result, the rubber composition obtained using this wet masterbatch also has excellent dispersibility of carbon black and uniform dispersibility.

  The pneumatic tire according to the present invention is obtained by using the rubber composition described above. As described above, the rubber composition according to the present invention has excellent dispersibility of carbon black and uniform dispersibility. By using such a rubber composition as a raw material, the pneumatic tire according to the present invention has, for example, reduced rolling resistance and excellent physical properties such as fatigue resistance and wear resistance.

Example of a diagram showing the mechanism that causes turbulent flow of the mixed solution in the tank Another example of a diagram showing the mechanism causing turbulent flow of the mixed solution in the tank

  In the method for producing a wet masterbatch according to the present invention, a carbon black-containing slurry solution and a rubber latex solution are mixed in a liquid phase and dried.

  The carbon black-containing slurry solution can be produced by mixing carbon black and a dispersion solvent. As a method of mixing carbon black and a dispersion solvent, there is a method of dispersing using a general disperser such as a high shear mixer, a homomixer, a ball mill, a bead mill, a high pressure homogenizer, an ultrasonic homogenizer, a colloid mill or the like. Can be mentioned.

  As the dispersion solvent, it is particularly preferable to use water, but for example, water containing an organic solvent may be used.

  The carbon black for adjusting the carbon black-containing slurry solution includes, for example, carbon black used in the normal rubber industry, such as SAF, ISAF, HAF, FEF, GPF, and other conductive materials such as acetylene black and ketjen black. Carbon black can be used. The carbon black may be a granulated carbon black granulated in the ordinary rubber industry in consideration of its handling properties, or may be an ungranulated carbon black.

  In the present invention, when a carbon black-containing slurry solution containing a dispersant is used as a raw material, a wet masterbatch with better carbon black dispersibility can be produced. As the dispersant, a surfactant known in the rubber industry can be used, and examples thereof include a nonionic surfactant, an anionic surfactant, a cationic surfactant, and a zwitterionic surfactant. . Among these, an anionic surfactant is particularly preferable.

  In addition to carbon black, the carbon black-containing slurry solution may contain various fillers such as silica, aluminum hydroxide, and magnesium hydroxide, an anti-aging agent, a vulcanization accelerator, and zinc oxide. In this case, these may be mixed with the dispersion solvent together with the carbon black, or may be mixed with the dispersion solvent in a separate process from the carbon black.

  As an anti-aging agent, an aromatic amine-based anti-aging agent, an amine-ketone-based anti-aging agent, a monophenol-based anti-aging agent, a bisphenol-based anti-aging agent, a polyphenol-based anti-aging agent, dithiocarbamic acid, which are usually used for rubber Anti-aging agents such as a salt-based anti-aging agent and a thiourea-based anti-aging agent may be used alone or in an appropriate mixture.

  As the vulcanization accelerator, sulfenamide vulcanization accelerator, thiuram vulcanization accelerator, thiazole vulcanization accelerator, thiourea vulcanization accelerator, guanidine vulcanization, which are usually used for rubber vulcanization. Vulcanization accelerators such as accelerators and dithiocarbamate vulcanization accelerators may be used alone or in admixture as appropriate.

  The rubber latex solution includes a natural rubber latex solution or a synthetic rubber latex solution. The natural rubber latex solution is a natural product produced by the metabolic action of plants, and a natural rubber / water system is particularly preferred in which the dispersion solvent is water. Examples of the synthetic rubber latex solution include those obtained by emulsion polymerization of styrene-butadiene rubber, butadiene rubber, nitrile rubber, and chloroprene rubber.

  Hereinafter, an embodiment of a method for producing a wet masterbatch according to the present invention will be described. FIG. 1 is an example of a diagram illustrating a mechanism that causes a turbulent flow of a mixed solution in a tank.

  In the method for manufacturing a wet masterbatch according to the present embodiment, a mixed solution containing the above-described carbon black-containing slurry solution and rubber latex solution is introduced into a tank, and a high-pressure airflow is injected into the mixed solution to enter the tank. By causing turbulent flow, a coagulation step for generating a coagulum from the mixed solution and a crushing step for crushing the coagulum by injecting a high-pressure air flow into the coagulum are performed simultaneously.

  The tank used in the method for manufacturing the wet masterbatch of the present invention is not particularly limited as long as it can effectively cause turbulent flow, but in the present embodiment, a cylindrical tank is used as an example. Will be described. It is preferable to use a cylindrical tank as the tank and optimize the discharge angle from the discharge nozzle of the high-pressure airflow described later to the inner wall surface of the tank because turbulent flow can be generated particularly effectively. In addition, when a cylindrical thing is used as a tank, the upper part may open, and you may use the tank of a closed system also including an upper part.

  As shown in FIG. 1, the cylindrical tank 1 is provided with one discharge nozzle 2 capable of discharging a high-pressure airflow from the wall surface into the tank 1. In the present embodiment, an example is shown in which high-pressure steam is introduced as a high-pressure air stream from the high-pressure air stream introduction pipe 3 and the high-pressure air stream is injected from the discharge nozzle 2 into the mixed solution previously introduced into the tank 1. As shown in FIG. 1, when the tank 1 has a cylindrical shape, the discharge angle of the high-pressure airflow with respect to the inner wall surface of the tank 1 is preferably 10 ° to 80 °, and more preferably 30 ° to 60 °. . By setting the discharge angle of the high-pressure airflow with respect to the inner wall surface of the tank 1 in such a range, the turbulent flow of the mixed solution is effectively generated, and the mixed solution is uniformly solidified by the shearing force caused by the turbulent flow, At the same time, this coagulum can be crushed. As a result, carbon black has excellent dispersibility, and a uniform coagulated product and crushed product thereof can be obtained. By using this as a raw material, a wet master batch having excellent dispersibility of carbon black and uniform dispersibility can be obtained. Can be manufactured.

In the present embodiment, high-pressure steam is used as the high-pressure airflow. However, in order to effectively generate a turbulent flow of the mixed solution and to solidify the mixed solution with certainty, the pressure of the high-pressure steam is set to 0.306 MPa (3. 12 kgf / cm ² ) or less is preferable. An example of the lower limit of the pressure is 0.205 MPa (2.09 kgf / cm ² ).

  In this invention, it is preferable that the flow velocity at the time of the injection of a high pressure airflow (this embodiment high pressure steam) is 20 m / s-120 m / s, and it is more preferable that it is 60 m / s-110 m / s. By making the flow velocity at the time of jetting the high-pressure air flow within such a range, turbulent flow of the mixed solution can be effectively caused in the tank.

  Moreover, in this invention, it is preferable that the temperature of the mixed solution after high pressure airflow (high pressure steam in this embodiment) injection is 10-120 degreeC, and it is more preferable that it is 40-100 degreeC. By setting the temperature of the mixed solution after jetting high-pressure air flow within such a range, a solidified product having excellent dispersibility and less foreign matter can be obtained with a high recovery rate. When a closed tank is used, the temperature of the mixed solution after jetting the high-pressure airflow is preferably 10 to 120 ° C. However, for example, when using an open tank with an open tank top, The temperature of the mixed solution after injection is preferably 40 ° C to 95 ° C.

  In the manufacturing method of the wet masterbatch of this invention, it is preferable to adjust the pH of a mixed solution to 3-4 by further adding an acid or a metal salt as a coagulant to a mixed solution. According to such a method for producing a wet masterbatch, combined with a physical shearing force due to turbulent flow, the mixed solution solidifies more rapidly and the dispersibility of the solidified product is further improved.

  As the coagulant, an acid such as formic acid or sulfuric acid usually used for coagulation of a rubber latex solution, or a metal salt such as sodium chloride can be used.

  In the method for producing a wet masterbatch according to the present invention, a carbon black-containing slurry solution and a rubber latex solution are mixed in a liquid phase and then dried. As a method for drying the carbon black-containing rubber latex solution, various drying devices such as an oven, a vacuum dryer, and an air dryer can be used.

  The wet masterbatch manufactured by the above-described wet masterbatch manufacturing method has excellent dispersibility of carbon black and uniform dispersibility. In this wet master batch, if necessary, silica, silane coupling agent, zinc oxide, stearic acid, sulfur, vulcanization accelerator, vulcanization accelerator, vulcanization retarder, organic peroxide, anti-aging agent, A rubber composition can be produced by including a softening agent such as wax or oil, a processing aid, and the like. As described above, since the wet masterbatch according to the present invention has excellent dispersibility of carbon black and uniform dispersibility, the rubber composition produced using the wet masterbatch also has excellent dispersibility of carbon black. And uniform dispersibility. In particular, a tire manufactured using this rubber composition, specifically a tire using the rubber composition according to the present invention for a tread rubber, a side rubber, a ply or belt coating rubber, or a bead filler rubber, has carbon black. Since the rubber portion is well dispersed, for example, rolling resistance is reduced, and various physical properties such as fatigue resistance and wear resistance are excellent.

[Other Embodiments]
(1) In the above-described embodiment, an example in which high-pressure steam is used as the high-pressure airflow has been shown. However, in the present invention, compressed air may be used as the high-pressure airflow. When using compressed air, when performing a coagulation | solidification process and a crushing process, while heating the inside of a tank suitably, while mixing a mixed solution reliably, the coagulum can be crushed. The method for heating the inside of the tank is not particularly limited, and the inside of the tank may be heated so that the temperature of the mixed solution after high-pressure airflow injection is 10 to 120 ° C. as described above.

  (2) In the above-described embodiment, a mixed solution containing the above-described carbon black-containing slurry solution and rubber latex solution is introduced into the tank, and a high-pressure air stream is injected into the mixed solution to cause turbulence in the tank. The example which performs simultaneously the coagulation | solidification process which generate | occur | produces a solidified material from a mixed solution, and the crushing process which injects a high-pressure airflow into this solidified material, and crushes a solidified material was shown. However, in the present invention, the above-described coagulation step is performed in such a manner that the carbon black-containing slurry solution is charged into the tank, and a high-pressure air current is injected into the carbon black-containing slurry solution to cause turbulence in the tank. It may be a step of adding a solution and generating a coagulum from the mixed solution. In this case, the rubber latex solution is solidified by physical shearing force due to turbulent flow before it is sufficiently mixed with the carbon black-containing slurry solution, and it is more certain that the solidified product becomes a lump like a rubber ball. Can be prevented. As a result, the dispersibility of carbon black is further improved, and a more uniform solidified product and its crushed material can be obtained. By using this as a raw material, the dispersibility of carbon black is further improved and the dispersibility is more uniform. Can be produced. In addition, it is possible to more reliably prevent the coagulated material from forming a lump like a rubber ball, so that the coagulated material and its crushed material can be easily dehydrated and dried in the subsequent process, further improving the productivity of the wet masterbatch. To do.

  (3) In the above-described embodiment, as shown in FIG. 1, the cylindrical tank 1 is provided with one discharge nozzle 2 capable of discharging a high-pressure airflow from the wall surface into the tank 1. showed that. However, in the present invention, as shown in FIG. 2, the cylindrical tank 1 may be provided with two discharge nozzles 2 capable of discharging a high-pressure air flow from the wall surface into the tank 1. Further, although not shown, three or more discharge nozzles may be provided. When a plurality of discharge nozzles are arranged, it becomes possible to cause a larger turbulent flow in the tank, and the dispersibility of carbon black is further excellent, and a particularly solidified product and its crushed material are obtained.

  Hereinafter, examples and the like specifically showing the configuration and effects of the present invention will be described. In addition, each performance evaluation of unvulcanized rubber and vulcanized rubber was performed as follows.

(1) Recovery rate of wet masterbatch The carbon black-containing slurry solution and the rubber latex solution are mixed and coagulated in the liquid phase and then dried, and the weight W1 of the recovered coagulum and the carbon before mixing and coagulation By calculating the value of (W1 / W2) × 100 from the total weight W2 of the carbon black charged into the black-containing slurry solution and the rubber solid content contained in the rubber latex solution, The recovery rate (%) was measured.

(2) Dispersibility of carbon black (Phillips method)
The dispersibility of carbon black in the vulcanized rubber produced was evaluated according to ISO / DIS11345 (B system). A larger evaluation value means better dispersibility.

(3) Dispersibility of carbon black (ASTM method)
The dispersibility of carbon black in the vulcanized rubber produced was evaluated according to ASTM D2663-69 (Method B). A larger evaluation value means better dispersibility.

(4) Fatigue resistance The fatigue resistance of the vulcanized rubber produced was evaluated according to JIS K6260. Evaluation is shown by index evaluation when Comparative Example 1 is set to 100, and the larger the value, the better the fatigue resistance.

(5) Exothermic property Exothermic property of the vulcanized rubber produced was evaluated by loss tangent tan δ. Tan δ was measured using a rheometer E4000 manufactured by UBM under the conditions of 50 Hz, 80 ° C., and dynamic strain of 2%, and the measured value was used as an index. The evaluation is shown by index evaluation when Comparative Example 1 is set to 100, and the smaller the value, the lower the exothermic property and the better.

  The raw materials used and the equipment used are as follows.

(Raw material)
a) Carbon black SAF ("Seast 9", manufactured by Tokai Carbon Co., Ltd.)
b) Dispersion solvent Water c) Rubber latex solution Natural rubber concentrated latex (manufactured by Regex Corp., DRC (Dry Rubber Content) = 60%) diluted to 25% by weight with distilled water d) coagulant formic acid (manufactured by Nacalai Tesque) 1st grade 85%) diluted with distilled water to 10% by weight

Examples 1-8
Carbon black was dispersed in pure water at a concentration of 20% by weight to prepare a slurry solution containing carbon black. The cylindrical tank shown in FIG. ). High-pressure steam (high-pressure steam gauge pressure 0.205 MPa (209 kgf / cm ² ), temperature 100 ° C.) is injected into this mixed solution as a high-pressure air flow to cause turbulent flow in the tank, thereby solidifying (solidifying) the mixed solution. Step) and crushing (crushing step). Here, the discharge angle of the high-pressure airflow with respect to the inner wall surface of the tank 1 was set to 30 °. Tables 1 and 2 show conditions for setting the temperature of the mixed solution and the flow rate of the high-pressure air flow for performing the solidification step and the crushing step.

  After completion of the coagulation step and the crushing step, the obtained crushed product of the coagulated product was left to stand in a vacuum dryer at 120 ° C. for 2 hours to produce a wet master batch.

  The obtained wet masterbatch and the following compounding agents were mixed to prepare an unvulcanized rubber composition. This unvulcanized rubber composition was vulcanized at 150 ° C. for 30 minutes to produce a vulcanized rubber. The results are shown in Tables 1 and 2.

The number of parts by weight indicated in each compounding agent means the number of parts by weight relative to 100 parts by weight of the rubber component.
e) Stearic acid (manufactured by NOF Corporation) 1 part by weight f) Anti-aging agent “6PPD” (manufactured by Monsanto) 1 part by weight g) Zinc flower “Zinc flower 1” (manufactured by Mitsui Kinzoku) 3 parts by weight h) Wax (Nippon Seiki Co., Ltd.) 1 part by weight i) Sulfur (Tsurumi Chemical Co., Ltd.) 2 parts by weight j) Vulcanization accelerator “CBS” (Sanshin Chemical Co., Ltd.) 1 part by weight

Comparative Examples 1-3
In the coagulation step, a vulcanized rubber was produced by the same method as in Example 1 except that a stirring blade (blade diameter φ400 mm) was used instead of the high pressure water vapor and high pressure water vapor was not used throughout the coagulation step and the crushing step ( Comparative Example 1). Also, in the crushing process, crushing blades (blade diameter φ116 mm (Comparative Example 2), blade diameter φ570 mm (Comparative Example 3)) are used instead of high-pressure steam, and high-pressure steam is not used throughout the solidification process and crushing process. Vulcanized rubber was produced in the same manner as in Example 1 (Comparative Example 2 and Comparative Example 3). The results are shown in Tables 1 and 2.

  From the results of Table 2, in the wet masterbatch production methods according to Examples 1 to 8, the wet masterbatch recovery rate is high, and the vulcanized rubber of the rubber composition obtained using the produced wet masterbatch It can be seen that the dispersibility of carbon black is excellent and the physical properties (fatigue resistance and heat generation) which are important when a pneumatic tire is used are also excellent.

  On the other hand, from the results of Table 1, in the wet masterbatch manufacturing methods according to Comparative Examples 1 to 3, the physical properties (anti-resistance) important when the wet masterbatch recovery rate, carbon black dispersibility, and pneumatic tires are used. It can be seen that both the fatigue property and the exothermic property are worse than the wet master batch production methods according to Examples 1 to 8.

Claims (8)

In the method for producing a wet masterbatch in which a carbon black-containing slurry solution and a rubber latex solution are mixed in a liquid phase and dried.
A mixed solution containing the carbon black-containing slurry solution and the rubber latex solution is put into a tank, and a high-pressure airflow is injected into the mixed solution to cause turbulence in the tank, thereby coagulating from the mixed solution. A solidification process for generating objects,
A method for producing a wet masterbatch, comprising simultaneously performing a crushing step of crushing the solidified product by injecting the high-pressure airflow onto the solidified product.   In the coagulation step, the carbon black-containing slurry solution is charged into the tank, a high-pressure air current is injected into the carbon black-containing slurry solution, and the rubber latex solution is charged while causing turbulence in the tank. The method for producing a wet masterbatch according to claim 1, wherein the coagulated product is generated from the mixed solution.   The method for producing a wet masterbatch according to claim 1 or 2, wherein compressed air or high-pressure steam is used as the high-pressure airflow.   The method for producing a wet masterbatch according to any one of claims 1 to 3, wherein a flow velocity at the time of jetting the high-pressure airflow is 20 m / s to 120 m / s.   The method for producing a wet masterbatch according to any one of claims 1 to 4, wherein the temperature of the mixed solution after the high-pressure airflow injection is 10 to 120 ° C.   The method for producing a wet masterbatch according to any one of claims 1 to 5, further comprising adjusting the pH of the mixed solution to 3 to 4 by adding an acid or a metal salt as a coagulant to the mixed solution. .   The rubber composition obtained using the wet masterbatch manufactured by the method in any one of Claims 1-6.   A pneumatic tire obtained using the rubber composition according to claim 7.

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