Continuous method acrylic emulsion preparation equipment and pH gradient regulation and control method

Abstract

The invention discloses continuous method acrylic emulsion preparation equipment and a pH gradient regulation and control method, and relates to the technical field of emulsion preparation, pH regulation and control are carried out aiming at polymerization reaction in the acrylic emulsion preparation process, the pH reaction environment in a kettle body is maintained by quantitatively supplementing an acid regulating agent with a corresponding pH value, and improvement is carried out on the basis. Firstly, two or more acid injection pipes are used for synchronous acid mixing, the pH value is adjusted in advance on the premise that polymerization reaction is not affected, an acid mixing disc is driven to rotate in a small range in cooperation with the rotation action of a stirring rod, and the purpose is to fully mix two or more acid regulating agents to obtain the acid regulating agent with the preset pH value. In the release process, a gradient acid injection process of outward diffusion from the center is adopted, so that the polymerization reaction is prevented from being influenced by large fluctuation of the pH value, and the pH environment of the whole polymerization reaction is in a relatively stable state.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of emulsion preparation, in particular to a continuous acrylic emulsion preparation device and a pH gradient control method. BACKGROUND

[0002] The continuous acrylic emulsion preparation process is the most efficient and stable production process, which is specifically through the reaction of monomers, initiators and emulsifiers and other raw materials under specific conditions, including temperature conditions, component ratio and pH environment. The pH environment control link is specifically reflected in the polymerization reaction stage and the post-processing stage.

[0003] In the reaction stage, it is required to maintain weak acidity, and in the post-processing stage, it is required to maintain weak alkalinity. The post-processing stage is a relatively stable state, and the stirring state is maintained under a specific temperature requirement to realize the mixing of the regulator (ammonia) and the emulsion to complete the pH adjustment. In the reaction stage, the weak acidic environment is mainly due to the presence of acidic monomers (such as acrylic acid). As the reaction continues, the acidic monomers are continuously consumed, resulting in an increase in pH value. Therefore, it is necessary to add weak acid agents in sequence to maintain a weak acidic environment. The pH-responsive monomer mentioned in the publication number CN116731239A can be referred to, but it needs to be explained that:

[0004] The pH environment has a great influence on the reaction process. If the weak acid agent added causes the pH value to be lower or higher than the preset value (weak acidity 5.0-6.0), it will affect the reaction process, such as a significant decrease in reaction stability, an increase in monomer hydrolysis, and a deterioration of emulsion performance. Therefore, the present application proposes a solution. SUMMARY

[0005] The purpose of the present application is to provide a continuous acrylic emulsion preparation device and a pH gradient control method. The pH environment control process in the polymerization reaction stage of the continuous acrylic emulsion preparation process is particularly important. Therefore, the present application adopts a gradient adjustment process to maintain the pH environment in the polymerization reaction stage.

[0006] The purpose of the present application can be achieved by the following technical solution: a continuous acrylic emulsion preparation device, comprising a kettle body, a pH detection structure and a stirring rod, the kettle body is provided with a driving assembly corresponding to the stirring rod outside, and two or more than two acid injection pipes are installed in the kettle body along the horizontal direction, the stirring rod is provided with a rotor ball corresponding to the upper end position inside the kettle body, and the rotor ball is provided with a positioning ball sleeve corresponding to the end of the acid injection pipe outside;

[0007] The positioning ball sleeve and the rotor ball are provided with a mixed acid disc at the gap, and the rotor ball and the positioning ball sleeve are provided with an acid injection port corresponding to the acid injection pipe, the stirring rod is hollow inside, and an inner lever is arranged at the center point region of the stirring rod.

[0008] Further arrangement: the mixed acid disc is provided with multiple groups of labyrinth sheets, the labyrinth sheets are arranged in a staggered manner, and the labyrinth sheet downwardly facing cross section includes an inclined shape and an arc shape.

[0009] Further arrangement: the pH detection structure is arranged in an equidistant staggered manner along the vertical direction outside the kettle body.

[0010] Further arrangement: an electric push rod is installed at the center point position of the upper end of the kettle body, and the inner stirring rod is slidingly connected in the stirring rod along the vertical direction through the electric push rod.

[0011] Further arrangement: the lower end of the stirring rod is in an open shape, a rubber bottom disc is installed at the bottom end position inside the kettle body, and the inner stirring rod is fixed at the center point position on the upper surface of the rubber bottom disc.

[0012] Further arrangement: the center point position of the rotor ball is hollow and is arranged as an acid storage bin, multiple groups of annular through grooves arranged in a horizontal direction are formed on the outer wall position of the lower end of the inner stirring rod corresponding to the acid storage bin, and a mixed acid port is formed on the outer wall position of the stirring rod corresponding to the annular through groove.

[0013] Further arrangement: a vertical groove arranged in a vertical direction is formed on the outer wall position of the lower end of the inner stirring rod corresponding to the acid storage bin, and the multiple groups of annular through grooves are connected through the vertical groove, and the upper end of the vertical groove does not extend into the acid storage bin.

[0014] The present application also proposes a pH gradient control method for a continuous acrylic emulsion preparation device, which includes a pH environment multi-value detection stage, a pH pre-adjustment stage and a release stage, and the following supplements are made:

[0015] pH environment multi-value detection stage: in the state that the stirring rod is in directional rotation, multiple pH detection structures are used to obtain the pH value of the mixed liquid in the kettle body, and the pH value state in the reaction process of the mixed liquid is judged in combination with the acrylic emulsion preparation process parameters;

[0016] pH pre-adjustment stage: pH pre-adjustment parameters are generated according to the pH value state obtained in the pH environment multi-value detection stage, two or more acid injection pipes are used to inject acidifiers with different pH values into the mixed acid disc at the same time, and the multiple groups of acidifiers are mixed through the mixed acid disc to obtain the pH value corresponding to the pH value state and remain in the acid storage bin;

[0017] Release stage: after the pH pre-adjustment stage is completed, the inner stirring rod is driven to move upward or downward by the electric push rod, so that the acidifier in the acid storage bin enters the annular through groove along the vertical groove, and the acidifier is supplemented into the mixed liquid through the directional rotation action of the stirring rod, and the adjustment action of the pH environment in the kettle body is completed.

[0018] The present application has the following advantages:

[0019] 1. pH control is performed during the polymerization stage of acrylic emulsion preparation. Specifically, the pH value of the acidifier is adjusted according to the pH value of the reaction environment inside the reactor. The purpose is to maintain the pH value of the reaction environment. Based on this, a certain amount of acidifier is injected simultaneously through the acid injection pipe. The difference is that two or more acid injection pipes are used for simultaneous acid mixing. The pH value is pre-adjusted without affecting the polymerization reaction. The whole process is coordinated with the stirring action during the polymerization reaction. When two or more acidifiers are injected simultaneously, the acid is fully mixed using the acid mixing pan to obtain the acidifier with the corresponding pH value, and it is mainly stored in the acid storage tank.

[0020] 2. Based on the above, this invention makes local improvements to the stirring rod structure by adding a sliding inner lever inside. Essentially, the acid adjuster in the acid storage tank will not directly enter the mixed liquid in the reactor body, but will be released in conjunction with the up-and-down movement of the inner lever. During the release process, the acid adjuster is mainly injected in a gradient manner from the center outward. The purpose is to avoid the acid adjuster being excessively concentrated in a local position of the mixed liquid, which would cause large pH fluctuations and affect the overall polymerization reaction process, thus keeping the pH environment of the overall polymerization reaction in a relatively stable state. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of the continuous acrylic emulsion preparation equipment proposed in this invention;

[0023] Figure 2 for Figure 1 Cross-sectional view of the middle vessel body;

[0024] Figure 3 for Figure 2 Vertical cross-section of the center positioning ball sleeve;

[0025] Figure 4 for Figure 2 A cross-sectional view of the center positioning ball sleeve;

[0026] Figure 5 for Figure 4 A cross-sectional view of the medium-mixed acid pan;

[0027] Figure 6 This is a cross-sectional view of the positioning ball sleeve corresponding to the stirring rod.

[0028] In the figure: 1, kettle body; 101, pH detection structure; 2, acid injection pipe; 3, electric push rod; 4, drive assembly; 5, positioning ball sleeve; 6, stirring rod; 7, rubber base; 8, inner stirring rod; 9, acid mixing disc; 901, labyrinth piece; 10, rotor ball; 1001, acid injection port; 11, vertical slot; 12, annular through groove. DETAILED DESCRIPTION

[0029] The technical solutions of the present application will be described below in conjunction with the embodiments. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0030] Embodiment one: for the polymerization reaction stage in the continuous preparation process of acrylic emulsion, the pH environment control process is particularly important, for which the present application adopts a gradient adjustment process to maintain the pH environment in the polymerization reaction stage, and the following technical solutions are proposed:

[0031] Reference Figures 1 to 6 The continuous acrylic emulsion preparation equipment in the embodiment includes a kettle body 1, a pH detection structure 101 and a stirring rod 6. The kettle body 1 is externally provided with a drive assembly 4 corresponding to the stirring rod 6, and two or more acid injection pipes 2 are installed in the kettle body 1 along the horizontal direction. The stirring rod 6 is provided with a rotor ball 10 corresponding to the upper end position inside the kettle body 1, and the rotor ball 10 is externally provided with a positioning ball sleeve 5 corresponding to the end of the acid injection pipe 2.

[0032] The gap between the positioning ball sleeve 5 and the rotor ball 10 is provided with an acid mixing disc 9, and the rotor ball 10 and the positioning ball sleeve 5 are provided with an acid injection port 1001 corresponding to the acid injection pipe 2. The stirring rod 6 is hollow inside, and the center point region of the stirring rod 6 is provided with an inner stirring rod 8. The acid mixing disc 9 is provided with multiple groups of labyrinth pieces 901, which are arranged in a staggered manner. The labyrinth pieces 901 have a downward-facing cross-section including an inclined shape and an arc shape. The pH detection structure 101 is vertically and equidistantly arranged outside the kettle body 1, including a pH environment multi-value detection stage, a pH pre-adjustment stage and a release stage, and the following is supplemented:

[0033] pH environment multi-value detection stage: when the stirring rod 6 is in a directional rotation state, multiple pH detection structures 101 are used to obtain the pH value of the mixed liquid in the kettle body 1, and the pH value state in the reaction process of the mixed liquid is judged in combination with the acrylic emulsion preparation process parameters;

[0034] pH pre-adjustment stage: pH pre-adjustment parameters are generated based on the pH value status obtained in the pH environment multi-value detection stage. Two or more acid injection tubes 2 are used to simultaneously inject acid adjusters with different pH values ​​into the acid mixing tray 9. After multiple acid adjusters are mixed through the acid mixing tray, the corresponding pH value is obtained and stored in the acid storage chamber.

[0035] Release stage: After the pH pre-adjustment stage is completed, the electric push rod 3 drives the inner lever 8 to move up or down, so that the acid adjuster in the acid storage tank enters the annular channel 12 along the vertical slot 11. The acid adjuster is then added to the mixture by the directional rotation of the stirring rod 6, thus completing the pH adjustment action in the vessel 1.

[0036] Working principle: This section explains the polymerization reaction stage in the continuous preparation process of acrylic emulsion, emphasizing the need for timely and quantitative replenishment of reagents, with particular attention required for pH control. Figure 1 and Figure 2 For example, during the continuous preparation process, the stirring rod 6 needs to be rotated at a constant speed in a directional manner, and the stirring rod 6 in this invention is specifically driven by the drive assembly 4;

[0037] The drive assembly 4 can be driven by a chain / gear transmission structure, which will not be explained in detail. The key point is that the pH value of the mixed liquid in the vessel 1 is obtained in real time by multiple pH detection structures 101, and then a certain amount of acid adjuster is injected through the acid injection port 2. It should be noted that the injection dosage and pH value of the acid adjuster are limited according to the pH value in the vessel 1.

[0038] Reference Figure 3 Explanation: The positioning ball sleeve 5 is directly fixed by multiple acid injection pipes 2, and the stirring rod 6 is equipped with a rotor ball 10 that cooperates with the positioning ball sleeve 5. Theoretically, the liquid level of the mixed liquid in the vessel body 1 should not be higher than the rotor ball 10, and further reference is made to... Figure 4 and Figure 5 A mixed acid plate 9 is installed in the gap of the inner wall of the positioning ball sleeve 5. When the stirring rod 6 rotates at a constant speed, the mixed acid plate 9 can rotate slightly.

[0039] Key content reference Figure 5 When the acid adjuster is injected from the acid injection tube 2 into the positioning ball sleeve 5, multiple streams of acid adjuster will first enter the mixing plate 9, and then... Figure 5 It is understandable that the acid mixing tray 9 includes multiple sets of maze plates 901, the purpose of which is to restrict the flow of multiple acid adjusters and ensure that the multiple acid adjusters are fully mixed. When the multiple acid adjusters have different pH values, after being fully mixed, an acid adjuster with the corresponding pH value can be obtained and stored in the acid storage chamber.

[0040] And in the pH pre-adjustment stage, first, according to the pH value in the kettle 1 inside, a plurality of different pH value of acid regulator is selected, in the initial state, the acid regulator is not mixed into the mixed liquid in the kettle 1 in the form of direct drop or flow, but the corresponding pH value of acid regulator is prepared by pre-storing and pre-adjusting, to avoid the state that the mixed liquid pH value fluctuates obviously when the acid regulator is directly mixed into the mixed liquid in the kettle;

[0041] Two or more than two acid injection pipes are used to synchronize acid mixing, the pH value is adjusted in advance under the premise of not affecting the polymerization reaction, the whole process is matched with the stirring action in the polymerization reaction process, when two or more than two acid regulators are injected synchronously, the acid mixing disc is used to fully mix the acid to obtain the acid regulator corresponding to the pH value, and the acid regulator is mainly stored in the acid storage bin.

[0042] Example two: based on example one, the release process of the acid regulator is supplemented:

[0043] The electric push rod 3 is installed at the center point position of the upper end of the kettle 1, the inner lever 8 is connected in the vertical direction in the stirring rod 6 through the electric push rod 3, the lower end of the stirring rod 6 is open, the rubber bottom disc 7 is installed at the bottom end position in the kettle 1, the inner lever 8 is fixed at the center point position on the upper surface of the rubber bottom disc 7, and the center point position of the rotor ball 10 is hollow and is set as an acid storage bin;

[0044] A plurality of groups of annular through grooves 12 arranged in the horizontal direction are arranged on the outer wall position corresponding to the lower end of the acid storage bin of the inner lever 8, the acid mixing port is arranged on the outer wall position corresponding to the annular through groove 12 of the stirring rod 6, the vertical slot 11 arranged in the vertical direction is arranged on the outer wall position corresponding to the lower end of the acid storage bin of the inner lever 8, the plurality of groups of annular through grooves 12 are connected through the vertical slot 11, and the upper end of the vertical slot 11 does not extend into the acid storage bin.

[0045] The scheme is described in combination with Figure 6 In the initial state, the inner lever 8 is maintained at a certain position through the electric push rod 3, which is specifically manifested as: the vertical slot 11 is always not connected with the inside of the acid storage bin, so that the acid regulator in the acid storage bin that has been prepared will not be directly mixed into the mixed liquid, on the contrary, when the electric push rod 3 drives the inner lever 8 to move upward, the acid regulator in the acid storage bin enters each annular through groove 12 in turn along the vertical slot 11, and slowly mixes into the mixed liquid along the acid injection port outside the stirring rod 6, so as to adjust the pH value of the mixed liquid, and the setting position of the rotor ball 10 needs to be further limited, to ensure that the rotor ball 10 is always located above the liquid level of the mixed liquid, so as to avoid the mixed liquid flowing back into the acid storage bin due to the principle of liquid level balance;

[0046] During the movement of the inner stirring rod 8, since the inner stirring rod 8 is moved by the electric push rod 3, the application drives the stirring rod 6 to rotate directionally through the chain / gear transmission type driving assembly 4, so that the upward and downward movement of the inner stirring rod 8 does not interfere with the rotating state of the stirring rod 6. In addition, when the acid storage bin is communicated through the vertical slot 11 and the annular through slot 12, the inner stirring rod 8 also moves upward and downward periodically.

[0047] The rubber bottom disc 7 arranged at the lower side of the inner stirring rod 8 is hollow in nature, and when the mixed liquid is injected into the kettle body 1, the rubber bottom disc 7 is passively compressed under the pressure of the mixed liquid, and drives the inner stirring rod 8 to move upward. The key is that the deformation degree of the rubber bottom disc 7 is forced to change when the inner stirring rod 8 moves upward and downward, thereby indirectly driving the mixed liquid to perform a wave stirring action in the vertical direction. The key purpose is:

[0048] The acid regulator is mainly in the form of gradient acid injection with the center expanding outward. After the prepared acid regulator is mixed into the mixed liquid from the acid injection port, on the one hand, it is stirred in the annular stirring mode by the stirring rod 6, and on the other hand, it is waved in the vertical direction by the rubber bottom disc 7, so as to ensure that the acid regulator is fully diffused into the mixed liquid. The purpose is to avoid excessive concentration of the acid regulator in the local position of the mixed liquid, which leads to large pH fluctuation and affects the overall polymerization reaction process, so that the pH environment of the overall polymerization reaction is in a relatively stable state.

[0049] In summary, for the pH regulation of the polymerization reaction in the preparation process of the acrylic emulsion, the essence is to maintain the pH reaction environment in the kettle by quantitatively supplementing the acid regulator with the corresponding pH value. Based on this, the improvement is first to mix the acid with two or more acid injection pipes synchronously, which pre-adjusts the pH value without affecting the polymerization reaction. Among them, the rotation of the stirring rod drives the acid mixing disc to rotate slightly, the purpose of which is to fully mix the two or more acid regulators to obtain the acid regulator with the preset pH value. In the release process, the gradient acid injection process with the center expanding outward is adopted to avoid large pH fluctuation and affect the polymerization reaction, so that the pH environment of the overall polymerization reaction is in a relatively stable state.

[0050] The preferred embodiments disclosed above are only used to help explain the application. The preferred embodiments do not describe all the details and limit the application to the specific embodiments. Obviously, many modifications and changes can be made according to the content of the specification. The embodiments are selected and described in the specification in order to better explain the principles and practical applications of the application, so that those skilled in the art can well understand and utilize the application. The application is limited by the claims and their entire scope and equivalents.

Claims

1. A continuous acrylic emulsion preparation apparatus, comprising a vessel (1), a pH detection structure (101), and a stirring rod (6), characterized in that, The vessel body (1) is provided with a drive assembly (4) corresponding to the stirring rod (6) on the outside, and two or more acid injection pipes (2) are installed in the vessel body (1) along the horizontal direction. The stirring rod (6) is provided with a rotor ball (10) at the upper end of the vessel body (1), and the rotor ball (10) is provided with a positioning ball sleeve (5) corresponding to the end of the acid injection pipe (2) on the outside. A mixing plate (9) is provided at the gap between the positioning ball sleeve (5) and the rotor ball (10), and the rotor ball (10) and the positioning ball sleeve (5) are provided with acid injection ports (1001) corresponding to the acid injection pipe (2). The stirring rod (6) is hollow inside, and an inner lever (8) is provided in the center area of ​​the stirring rod (6).

2. The continuous acrylic emulsion preparation equipment according to claim 1, characterized in that, The mixed acid plate (9) is provided with multiple sets of maze plates (901), which are arranged in an alternating manner, and the cross-section of the maze plates (901) includes oblique and arc shapes.

3. The continuous acrylic emulsion preparation equipment according to claim 2, characterized in that, The pH detection structure (101) is arranged in an equidistant, staggered manner along the vertical direction outside the vessel body (1).

4. The continuous acrylic emulsion preparation equipment according to claim 3, characterized in that, An electric push rod (3) is installed at the center of the upper end of the vessel body (1), and the inner lever (8) is slidably connected in the vertical direction in the stirring rod (6) through the electric push rod (3).

5. The continuous acrylic emulsion preparation equipment according to claim 4, characterized in that, The lower end of the stirring rod (6) is open, and a rubber base (7) is installed at the bottom of the inside of the vessel body (1). The lower end of the inner lever (8) is fixed at the center point of the upper surface of the rubber base (7).

6. The continuous acrylic emulsion preparation equipment according to claim 5, characterized in that, The center point of the rotor ball (10) is hollow and is set as an acid storage chamber. The inner lever (8) has multiple sets of horizontally arranged annular grooves (12) on the outer wall of the lower end of the acid storage chamber. The stirring rod (6) has a mixed acid port on the outer wall of the annular grooves (12).

7. The continuous acrylic emulsion preparation equipment according to claim 6, characterized in that, The inner lever (8) has a vertically arranged slot (11) on the outer wall of the lower end of the acid storage chamber. Multiple sets of annular through slots (12) are connected through the vertical slot (11). The upper end of the vertical slot (11) does not extend into the acid storage chamber.

8. A pH gradient control method for a continuous acrylic emulsion preparation apparatus, applied in the continuous acrylic emulsion preparation apparatus as described in claim 7, characterized in that, It includes a multi-value detection stage for pH environment, a pH pre-adjustment stage, and a release stage, and is supplemented as follows: pH environment multi-value detection stage: When the stirring rod (6) is in a directional rotation state, the pH value of the mixture in the vessel (1) is obtained by multiple pH detection structures (101), and the pH value of the mixture during the reaction process is judged in combination with the acrylic emulsion preparation process parameters. pH pre-adjustment stage: pH pre-adjustment parameters are generated based on the pH value status obtained in the pH environment multi-value detection stage. Two or more acid injection tubes (2) are used to simultaneously inject acid adjusters with different pH values ​​into the acid mixing tray (9). Multiple acid adjusters are mixed through the acid mixing tray to obtain the corresponding pH value status and are stored in the acid storage tank. Release stage: After the pH pre-adjustment stage is completed, the electric push rod (3) drives the inner lever (8) to move up or down, so that the acid adjuster in the acid storage chamber enters the annular through groove (12) along the vertical slot (11), and the acid adjuster is added to the mixture by the directional rotation of the stirring rod (6), thus completing the pH adjustment action in the vessel (1).

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