Pre-dispersing and mixing system for high-filling-amount precipitation-method white carbon black

Abstract

The utility model relates to a pre-dispersing and mixing system for white carbon black by a high filling amount precipitation method, which is characterized in that a liquid storage tank is used for storing a liquid silane coupling agent, a first mixing tank is used for mixing the white carbon black with the liquid silane coupling agent, and a second mixing tank is used for further mixing a mixed material in the first mixing tank with a white carbon black dispersing agent; the liquid storage tank is connected with a plurality of coupling agent feeding ports of the first mixing tank through a first conveying pump, a first discharging port of the first mixing tank is connected with a second feeding port of the second mixing tank through a second conveying pump, a stirrer of the first mixing tank is transversely arranged, and a stirrer in the second mixing tank is longitudinally arranged. According to the device, white carbon black filler can be premixed twice, the first mixing tank can complete primary pretreatment on white carbon black by a coupling agent, the mixing efficiency is more uniform and efficient, and secondary pretreatment on a dispersing agent and the white carbon black can be completed in the second mixing tank, so that a mixture circularly flows up and down in the tanks along with stirring, and the dispersing agent is uniformly mixed within a short time.

Description

Technical Field

[0001] The utility model relates to the technical field of rubber mixing, in particular to a pre-dispersion mixing system for precipitated silica with a high filling amount. Background Art

[0002] In order to improve the rolling resistance and grip performance of the tread of a car tire, a large amount of precipitated silica needs to be added to the tread rubber compound as a filler to further reduce the rolling resistance. However, the compatibility between hydrophilic precipitated silica and lipophilic rubber is poor because the surface of precipitated silica contains a large number of silanol groups. After a large amount of filling in the rubber compound, strong hydroxyl interactions between particles form hydrogen bonds, resulting in the easy agglomeration of precipitated silica. The higher the content of precipitated silica filled in the tread rubber, the more serious the agglomeration. The poor dispersion of precipitated silica in rubber will lead to a reduction in its reinforcing effect. For example, it increases the processing difficulty: poor dispersion increases the mixing energy consumption, raises the production cost, and may also lead to increased wear of processing equipment; it affects the processing performance of materials: the agglomerates of precipitated silica may increase the viscosity of the material, resulting in problems such as sticking to the roller and die during the processing; it reduces the product performance: the agglomerates of precipitated silica may form stress concentration points in the material, affecting the mechanical stability and durability of the product.

[0003] Therefore, the industry generally adopts the method of adding silane coupling agents and precipitated silica dispersants to improve the strong interaction between precipitated silicas and at the same time enhance the chemical interaction between the filler and the rubber. For the tread rubber filled with a high content of precipitated silica, although the interaction between fillers can be relatively improved, internal filler networks will still form between many local fillers, resulting in a relatively high Mooney viscosity and poor mixing and extrusion processing performance. During mixing, phenomena such as broken pieces and pitted surfaces are likely to occur, and problems such as breakage during the extrusion process and poor sheet formation will affect the production continuity. Summary of the Utility Model

[0004] In view of the above problems, the utility model proposes a pre-dispersion mixing system for precipitated silica with a high filling amount, which breaks the agglomerates between fillers through first mixing with a silane coupling agent and then blocks the re-formation of agglomerates between fillers through second mixing with a dispersant.

[0005] To achieve the above object, the following technical solution is adopted: A pre-dispersion mixing system for precipitated silica with a high filling amount includes a liquid storage tank, a first mixing tank, and a second mixing tank. Among them, the liquid storage tank is used for storing liquid silane coupling agent, the first mixing tank is used for mixing precipitated silica with the liquid silane coupling agent, and the second mixing tank is used for further mixing the mixed material in the first mixing tank with a precipitated silica dispersant.

[0006] The described first mixing tank includes a first stirrer, a first feeding port, a first discharging port, and several coupling agent feeding ports. Along the axial direction of the first stirrer, several stirring blades are arranged. The first stirrer is horizontally arranged inside the first mixing tank, and there is a gap between the stirring blades and the inner wall of the first mixing tank.

[0007] The described second mixing tank includes a second stirrer, a second feeding port, a second discharging port, and a dispersant feeding port. The second stirrer is longitudinally arranged inside the second mixing tank. Along the axial direction, the second stirrer is provided with three sections of stirring blades, including an upper section stirring blade, a middle section stirring blade, and a final section stirring blade. The upper section stirring blade forms a downward inclination angle with the horizontal direction, the middle section stirring blade is parallel to the horizontal direction, and the final section stirring blade forms an upward inclination angle with the horizontal direction.

[0008] The described liquid storage tank is connected to several coupling agent feeding ports of the first mixing tank through a first transfer pump. The first discharging port of the first mixing tank is connected to the second feeding port of the second mixing tank through a second transfer pump.

[0009] Furthermore, atomizing nozzles are provided at several coupling agent feeding ports of the first mixing tank, and the liquid storage tank is connected to the atomizing nozzles through a first transfer pump.

[0010] Furthermore, the stirring blades are plow blade type blades.

[0011] Furthermore, the distance from the upper section stirring blade to the middle section stirring blade is equal to the distance from the final section stirring blade to the middle section stirring blade.

[0012] Furthermore, the first mixing tank further includes a first exhaust port, and the second mixing tank further includes a second exhaust port.

[0013] Advantages of the present utility model: This new type can perform two - stage premixing on the silica filler. The first mixing tank can complete the primary pretreatment of the coupling agent on the silica, improving the strong hydrogen - bond binding effect between the fillers, and can improve the poor dispersibility of silica during the mixing process, avoiding the problem of flocculation between the fillers. In the second mixing tank, the secondary pretreatment of the dispersant and silica can be completed, blocking the re - interaction between the silicas to form agglomerates. It can avoid uneven mixing when adding the coupling agent and the dispersant during mixing, and prevent the formation of an internal filler network in local fillers.

[0014] The plow - blade type stirring blades in the first mixing tank of this new type can continuously push the mixed materials towards the inner wall of the tank. The atomizing nozzles can evenly spray the liquid on the surface of the mixed materials to continuously mix them, enabling the silane coupling agent to fully penetrate into the micropores of the material, breaking the strong hydrogen - bond binding effect between the silica fillers. Compared with the traditional mixing tank, the mixing efficiency is more uniform and efficient, avoiding local unevenness.

[0015] In the design of the stirring blades of the second mixing tank of the present invention, the upper stirring blades cause the mixture located in the upper part to flow downward, and the end stirring blades cause the mixture at the bottom to flow upward, so that the mixture circulates up and down in the tank during stirring. On the one hand, it enables the dispersant to be evenly mixed in a short time, preventing the re-formation of agglomerates due to the interaction between the silica fillers. On the other hand, it avoids the problem of mixing stratification caused by the smaller specific gravity of the dispersant compared to the filler. Brief Description of the Drawings

[0016] Figure 1 is a schematic structural diagram of the present invention;

[0017] Figure 2 is a schematic diagram of the first mixing tank;

[0018] Figure 3 is a schematic diagram of the second mixing tank.

[0019] As shown in the figure: 1. Liquid storage tank; 2. First mixing tank; 3. Second mixing tank; 4. First transfer pump; 5. Second transfer pump; 200. First stirrer; 201. First feeding port; 202. First discharging port; 203. First exhaust port; 204. Atomizing nozzle; 205. Stirring blade; 300. Second stirrer; 301. Second feeding port; 302. Second discharging port; 303. Dispersant feeding port; 304. Second exhaust port; 305. Upper stirring blade; 306. Middle section stirring; 307. End stirring blade. Detailed Embodiments

[0020] Embodiment 1

[0021] The following is further described in conjunction with the drawings. As Figures 1 - 3 shown, a pre-dispersion mixing system for high-filled precipitated silica includes a liquid storage tank 1, a first mixing tank 2 and a second mixing tank 3. Among them, the liquid storage tank 1 is used to store the liquid silane coupling agent, the first mixing tank 2 is used for mixing silica with the liquid silane coupling agent, and the second mixing tank 3 is used for further mixing the mixture in the first mixing tank 2 with the silica dispersant.

[0022] The first mixing tank 2 includes a first stirrer 200, a first feeding port 201, a first discharging port 202, a plurality of coupling agent feeding ports and a first exhaust port 203. The first feeding port 201, the coupling agent feeding ports and the first exhaust port 203 are all arranged at the top of the tank body. The first discharging port 202 is arranged at the bottom of the tank body. An atomizing nozzle 204 is arranged on each coupling agent feeding port. A plurality of stirring blades 205 are arranged axially on the first stirrer 200. The stirring blades 205 adopt plow-shaped blades. The first stirrer 200 is arranged horizontally in the first mixing tank 2, and a gap is ensured between the stirring blades 205 and the inner wall of the first mixing tank 1.

[0023] The second mixing tank 3 includes a second stirrer 300, a second feeding port 301, a second discharging port 302, a dispersant feeding port 303 and a second exhaust port 304. The second feeding port 301, the dispersant feeding port 303 and the second exhaust port 304 are arranged at the top of the tank body, the second discharging port 302 is arranged at the bottom of the tank body, the second stirrer 300 is longitudinally arranged in the second mixing tank 3, and the second stirrer 300 is axially provided with three sections of stirring blades, including an upper section stirring blade 305, a middle section stirring blade 306 and a terminal stirring blade 307. The upper section stirring blade 305 forms a downward inclination angle with the horizontal direction, so that when stirring, the mixture at the upper end is pushed downward. The middle section stirring blade 306 is consistent with the horizontal direction, and the terminal stirring blade 307 forms an upward inclination angle with the horizontal direction, so that when stirring, the mixture at the bottom is pushed upward. The middle section stirring blade 306 can be set as multiple groups of stirring blades arranged longitudinally. The distance from the upper section stirring blade 305 to the middle section stirring blade 306 is equal to the distance from the terminal stirring blade 307 to the middle section stirring blade 306.

[0024] The liquid storage tank 1 is connected to the atomizing nozzle 204 of the coupling agent feeding port of the first mixing tank 2 through the first delivery pump 4. The first discharging port 202 of the first mixing tank 2 is connected to the second feeding port 301 of the second mixing tank 3 through the second delivery pump 5.

[0025] The mixing process of this embodiment is as follows: Solid powder silica is added to the first mixing tank 2 through the first feeding port 201. After adding, the first feeding port 201 of silica is closed, the motor of the first stirrer 200 is started, and the silica powder is stirred for 5 minutes. Then the first delivery pump 4 is turned on, and the liquid silane coupling agent is sprayed out through the atomizing nozzle 204, converting from a continuous liquid into a mist. The injection speed of the liquid silane coupling agent is 0.8 - 1 kg / min. The rotation speed of the motor of the first stirrer 200 is controlled at 40 revolutions per minute. After the liquid silane coupling agent is added, the first delivery pump 4 is turned off, and then stirring continues for 30 minutes to achieve sufficient mixing and form a mixed material a. During the stirring process, the plow blade of the first stirrer 200 enables the silica filler to continuously update the surface in contact with the tank wall, and the liquid silane coupling agent is evenly sprayed in the silica powder. The full contact between the two improves the strong interaction between the silica fillers. The silica powder is prone to agglomeration due to electrostatic force and van der Waals force. The plow blade breaks the agglomerates, and the silane coupling agent is evenly dispersed on the material surface through the atomizing nozzle, thereby increasing the contact area and reaction efficiency between the silane coupling agent and the material. The atomized silane coupling agent can more effectively penetrate into the micropores of the material and enhance its binding force with the material.

[0026] Immediately after the formation of the mixed material a, the second transfer pump 5 is started, and the mixed material a is fed into the second mixing tank 3 through the second feeding port 301. Meanwhile, the silica white dispersant is added into the second mixing tank 3 through the dispersant feeding port 303. After the two parts of feeding are completed, the corresponding feeding ports are closed. The motor of the second stirrer 300 is started, and its rotation speed is controlled at 30 r / min. Stir for 20 min to achieve component mixing, and discharge it from the second discharge port 302. During the stirring process, the mixed material a and the silica white dispersant are mixed under mechanical stirring. The material in the upper half flows from top to bottom under the action of the upper stirring blades 305, and the material at the bottom flows from bottom to top under the action of the end stirring blades 307, so that the material in the tank forms an alternating cyclic up-and-down flow type stirring, making the silica white dispersant evenly mixed with the mixed material a without stratification. The silica white dispersant is adsorbed on the silica white filler in the mixed material a, and by means of electrostatic repulsion or steric hindrance, the aggregation between the silica white particles in the mixed material a is prevented, realizing stable dispersion.

[0027] The present utility model is not limited to this embodiment. Any equivalent concept or change within the technical scope disclosed in the present utility model shall be included in the protection scope of the present utility model.

Claims

1. A pre-dispersion mixing system for precipitated silica with a high filling amount, comprising a liquid storage tank (1), a first mixing tank (2) and a second mixing tank (3), wherein, The liquid storage tank (1) is used for storing liquid silane coupling agent, the first mixing tank (2) is used for mixing fumed silica and liquid silane coupling agent, and the second mixing tank (3) is used for further mixing the mixture in the first mixing tank (2) with fumed silica dispersant. It is characterized in that, The first mixing tank (2) includes a first stirrer (200), a first feeding port (201), a first discharging port (202) and a plurality of coupling agent feeding ports. A plurality of stirring blades (205) are arranged axially on the first stirrer (200). The first stirrer (200) is arranged horizontally in the first mixing tank (2). There is a gap between the stirring blades (205) and the inner wall of the first mixing tank (2). The second mixing tank (3) includes a second stirrer (300), a second feeding port (301), a second discharging port (302) and a dispersant feeding port (303). The second stirrer (300) is arranged longitudinally in the second mixing tank (3). The second stirrer (300) is arranged with three sections of stirring blades axially, including an upper section stirring blade (305), a middle section stirring blade (306) and a terminal stirring blade (307). The upper section stirring blade (305) forms a downward inclination angle with the horizontal direction, the middle section stirring blade (306) is parallel to the horizontal direction, and the terminal stirring blade (307) forms an upward inclination angle with the horizontal direction. The liquid storage tank (1) is connected to the plurality of coupling agent feeding ports of the first mixing tank (2) through a first delivery pump (4). The first discharging port (202) of the first mixing tank (2) is connected to the second feeding port (301) of the second mixing tank (3) through a second delivery pump (5).

2. The pre-dispersion mixing system according to claim 1, wherein Atomizing nozzles (204) are provided at the plurality of coupling agent feeding ports of the first mixing tank (2). The liquid storage tank (1) is connected to the atomizing nozzles (204) through a first delivery pump (4).

3. The pre-dispersion mixing system according to claim 2, wherein The stirring blades (205) are plow blade type blades.

4. The pre-dispersion mixing system according to claim 3, wherein, The distance from the upper section stirring blade (305) to the middle section stirring blade (306) is equal to the distance from the terminal stirring blade (307) to the middle section stirring blade (306).

5. The pre-dispersion mixing system according to claim 4, wherein, The first mixing tank (2) further includes a first exhaust port (203), and the second mixing tank (3) further includes a second exhaust port (304).

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