High-concentration universal slurry

Abstract

The invention relates to the technical field of slurry preparation, and discloses a high-concentration general slurry, which comprises the following components by mass: 1200-1300 parts of butyl ester; 550 to 650 parts by mass of methacrylic acid; 550 to 600 parts by mass of styrene; 70 to 80 parts by mass of methyl methacrylate; 6000 to 6500 parts by mass of process water; 0.5-2 parts by mass of an enzyme preparation; 6-8 parts by mass of an ammonium persulfate solution; 8-10 parts by mass of an ammonium persulfate initiator; 300 to 350 parts by mass of ammonia water; and 1300 to 1500 parts by mass of an auxiliary agent. According to the preparation method, an enzyme preparation is adopted as an initiator component, a traditional chemical initiator is partially replaced, the energy consumption of a polymerization reaction and the influence on the environment are reduced, green membrane separation post-treatment and low-temperature concentration technologies are introduced, and unreacted monomers and low-molecular-weight impurities are removed under mild conditions.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of slurry preparation, in particular to high-concentration universal slurry. BACKGROUND

[0002] High-molecular water-based dispersions, commonly known as slurry or emulsion, have become an indispensable basic material. They have the characteristics of low volatile organic compound (VOC) content, easy operation and environmental friendliness, and are widely used in many industries such as coatings, adhesives, textile processing, paper processing, and building materials.

[0003] In the prior art, the preparation of high-concentration universal slurry is mainly realized by traditional emulsion polymerization methods. These methods usually involve using chemical initiators (such as persulfate, peroxide, etc.) to initiate monomer polymerization at a certain temperature. In order to obtain the required solid content and performance, subsequent treatment is often needed after polymerization, such as evaporation of part of the water by heating for concentration, or removal of a small amount of coarse particles generated during polymerization by physical filtration means.

[0004] However, the existing high-concentration universal slurry has poor control accuracy in the existing production process, resulting in fluctuations in product quality. Lack of real-time accurate monitoring and dynamic adjustment of reaction parameters such as monomer conversion rate, viscosity, and pH value, when pursuing high solid content, the viscosity of the slurry often increases sharply, making it difficult to process pumping, coating, etc., and improper pH value or internal instability factors are easy to cause delamination, precipitation or gelation, which seriously shortens the storage life Therefore, the present application provides a high-concentration universal slurry to solve the problems existing in the prior art. SUMMARY

[0005] In view of the deficiencies of the prior art, the purpose of the present application is to provide a high-concentration universal slurry, which solves the problems of poor stability of existing slurry, short storage life, low monomer conversion rate in the production process, and high residual monomer content.

[0006] To achieve the above purpose, the present application is realized by the following technical scheme: The present application provides a high-concentration universal slurry, which comprises the following components by mass fraction: monomer components, a total of 2500-2700 parts by mass, wherein butyl ester 1200-1300 parts by mass, methacrylic acid 550-650 parts by mass, styrene 550-600 parts by mass, methyl methacrylate 70-80 parts by mass; process water 6000-6500 parts by mass; initiator component, 0.5-2 parts by mass of enzyme preparation, and as an auxiliary initiator, ammonium persulfate solution 6-8 parts by mass and ammonium persulfate initiator 8-10 parts by mass; auxiliary component, a total of 1300-1500 parts by mass, said auxiliary including dispersant 60-70 parts by mass composed of sodium polyacrylate, stabilizer 8-12 parts by mass composed of polyvinyl alcohol, chain transfer agent solution 2-3 parts by mass composed of mercaptoethanol, white powder solution 1-2 parts by mass composed of sodium hyposulfite formaldehyde, defoamer X-18C solution 10-12 parts by mass composed of polydimethylsiloxane, ammonia 300-350 parts by mass, smoothing agent P226 50-700 parts by mass composed of polyalkylene glycol or amino silicone oil, defoamer X-10C 12-18 parts by mass composed of polydimethylsiloxane, antistatic agent PN250-270 parts by mass composed of quaternary ammonium salt or polyethylene glycol ester, and bactericide 15-20 parts by mass composed of isothiazolinone.

[0007] The high-concentration universal slurry is polymerized by specific proportioning of monomer components, combined with the catalytic action of enzyme preparation, to realize high-concentration polymerization of the slurry. Various auxiliaries in the formula, such as dispersant, stabilizer, chain transfer agent, defoamer, smoothing agent, antistatic agent and bactericide, synergistically ensure the stability, rheological property, defoaming performance and storage performance of the slurry. Precise control of the concentration, viscosity and pH value of the slurry makes the slurry have specific physical and chemical properties in application.

[0008] Preferably, the enzyme preparation is laccase or catalase. The application of enzyme preparation reduces the energy consumption of polymerization reaction, and can reduce the amount of traditional chemical initiator, which helps the green preparation of the slurry.

[0009] Preferably, the concentration of the ammonium persulfate solution and the ammonium persulfate initiator is 1-5% (w / v). By controlling the concentration of the initiator, the polymerization reaction rate and the molecular weight of the product can be accurately controlled.

[0010] Preferably, the process water is deionized water or pure water, and the ammonia water is an aqueous solution of ammonium hydroxide used to neutralize residual acidic substances. The use of high-purity process water can avoid the influence of impurities on the polymerization reaction and the performance of the final slurry. Ammonia water is used as a pH regulator to accurately control the acidity and alkalinity of the slurry to meet the requirements of subsequent application and storage stability.

[0011] The second aspect of the present application provides a preparation method of a high-concentration universal slurry, for preparing the above-mentioned high-concentration universal slurry, comprising the following steps: S1, raw material preparation and premixing: in a mixing tank, add monomer components according to the specified ratio, the monomer components include butyl ester 1200-1300 parts by mass, methacrylic acid 550-650 parts by mass, styrene 550-600 parts by mass, methyl methacrylate 70-80 parts by mass, and stir and mix for 30-60 minutes to form a monomer mixture.

[0012] S2, enzyme catalytic polymerization reaction: in a reaction kettle, add process water 6000-6500 parts by mass, dispersant composed of sodium polyacrylate 60-70 parts by mass, and stabilizer composed of polyvinyl alcohol 8-12 parts by mass, under the conditions of stirring speed 45±5 rpm and polymerization reaction temperature 95-96℃, add 0.5-2 parts by mass of enzyme preparation, 6-8 parts by mass of ammonium persulfate solution as auxiliary initiator, 8-10 parts by mass of ammonium persulfate initiator, 2-3 parts by mass of chain transfer agent solution composed of mercaptoethanol, and 1-2 parts by mass of ivory powder solution composed of sodium hydrosulfite formaldehyde, the dropping rate is 3-8 kg / min; after the dropping is completed, the reaction temperature is maintained for 1-3 hours to complete the polymerization reaction. This step realizes the polymerization reaction of monomers through enzyme catalysis. The accurate control of stirring speed, polymerization reaction temperature, and the dropping speed and ratio of initiators and auxiliary initiators ensures the smooth progress of the polymerization reaction and the stability of polymer yield and performance.

[0013] S3, post-treatment and sizing: the polymer generated by the reaction is cooled to 70-80℃ and filtered with a 150-170 mesh filter bag, then 10-12 parts by mass of defoamer X-18C solution composed of polydimethylsiloxane, 300-350 parts by mass of ammonia, 50-700 parts by mass of smoothing agent P226 composed of polyalkylene glycol or amino silicone oil, 12-18 parts by mass of defoamer X-10C composed of polydimethylsiloxane, 250-270 parts by mass of antistatic agent PN composed of quaternary ammonium salt or polyethylene glycol ester, and 15-20 parts by mass of bactericide composed of isothiazolinone are added in turn, and stirred uniformly to form the final slurry.

[0014] S4, quality control: detect the sugar content concentration, viscosity, pH value and other indicators of the final slurry, and adjust according to the detection results to make the sugar content concentration 25.0-25.2, the viscosity less than 200 mPa·s, and the pH value 6.5-7.5.

[0015] Preferably, the enzyme preparation is laccase or catalase. Specific substrate addition or gas sparging methods are further provided for different enzyme preparations. If catalase is used, an additional 0.1-1.0% (w / v) hydrogen peroxide solution is slowly added as substrate by a peristaltic pump at a rate of 0.05-0.1 kg / min; if laccase is used, clean air or oxygen is continuously sparged to maintain the dissolved oxygen concentration during the reaction. This differential operation ensures the maintenance of enzyme activity and the efficiency of the polymerization reaction.

[0016] Preferably, during the process of adding monomer mixture and initiator component, the online near-infrared spectroscopy or Raman spectroscopy sensor and online viscosity sensor are turned on and connected to the intelligent control system, which analyzes the online spectral data to monitor the monomer conversion rate in real time, monitors the slurry viscosity in real time, monitors the pH value in the reactor in real time, and dynamically adjusts the monomer addition rate, stirring speed or pH value according to the preset threshold or range. This intelligent online monitoring and real-time control realizes precise control of the polymerization process, reduces human intervention, and improves the consistency of product quality and production efficiency.

[0017] In summary, the present application includes at least one of the following beneficial technical effects: 1. The present application uses enzyme preparation as initiator component, which partially replaces traditional chemical initiator, reduces the energy consumption of polymerization reaction and the impact on the environment. At the same time, the green membrane separation post-treatment and low-temperature concentration technology is introduced, which removes unreacted monomers and low molecular weight impurities under mild conditions, and realizes slurry concentration, avoiding the traditional high-temperature and high-energy consumption concentration method.

[0018] 2. The present application monitors the monomer conversion rate, slurry viscosity and pH value in the reactor in real time, and dynamically adjusts the monomer addition rate, stirring speed or pH value according to the preset threshold or range. This intelligent real-time monitoring and control significantly improves the accuracy, stability and repeatability of the polymerization reaction, reduces human error, and thus improves the production efficiency and consistency of product quality.

[0019] 3. The present application controls the mass fraction of monomer components, process water and various additives, and regulates the concentration, viscosity and pH value of the slurry after polymerization, so that the prepared high-concentration universal slurry has good fluidity and suitable acidity and alkalinity while maintaining high solid content. This ensures the physical and chemical stability of the slurry during storage and subsequent application, reducing the risk of stratification, precipitation or gelation. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 is a preparation method flow chart of the present application. DETAILED DESCRIPTION

[0021] The following drawings form part of the present disclosure Figure 1 The present application is further described in detail.

[0022] The main raw materials and reagents used in the following examples and comparative examples are as follows, and the reagents not specifically described are commercially available analytical pure or higher grade products.

[0023] Laccase: CAS No. 80498-15-3.

[0024] Catalase: CAS No. 9001-05-2.

[0025] Ammonium persulfate: CAS No. 7727-54-0.

[0026] Sodium polyacrylate: CAS No. 9003-04-7.

[0027] Polyvinyl alcohol: CAS No. 9002-89-5.

[0028] Mercaptoethanol: CAS No. 60-24-2.

[0029] Please refer to the attached Figure 1 Example 1: Raw material components (by mass fraction): Butyl ester: 1250 parts by mass; methacrylic acid: 600 parts by mass; styrene: 580 parts by mass; methyl methacrylate: 75 parts by mass; process water: 6200 parts by mass; laccase: 1 part by mass; ammonium persulfate solution (concentration 1% (w / v)): 7 parts by mass; ammonium persulfate initiator (concentration 1% (w / v)): 9 parts by mass; sodium polyacrylate (dispersant): 65 parts by mass; polyvinyl alcohol (stabilizer): 10 parts by mass; mercaptoethanol (chain transfer agent solution): 2.5 parts by mass; sodium bisulfite formaldehyde (talcum powder solution): 1.5 parts by mass; polydimethylsiloxane (antifoaming agent X-18C solution): 11 parts by mass; ammonia: 320 parts by mass; polyalkylene glycol (smoothing agent P22): 680 parts by mass; polydimethylsiloxane (antifoaming agent X-10C): 15 parts by mass; quaternary ammonium salt (antistatic agent PN): 260 parts by mass; isothiazolinone (bactericide): 18 parts by mass.

[0030] Preparation steps: S1, raw material preparation and premixing: In a mixing tank, butyl ester, methacrylic acid, styrene and methyl methacrylate are added in sequence. Start stirring at 50 rpm for 45 minutes to form a monomer mixture.

[0031] S2, Enzyme catalyzed polymerization reaction: In a 15 cubic meter reactor, process water, sodium polyacrylate and polyvinyl alcohol were added. The stirring was started and the stirring speed was set to 45 rpm. The reactor was heated to reach the temperature of 95°C. When the temperature was stable, the following solutions were added by dropping at the rate of 5 parts by mass per minute by using a peristaltic pump: laccase, ammonium persulfate solution, ammonium persulfate initiator, mercaptoethanol and sodium hydrosulfite formaldehyde. During the dropping, the reaction temperature was maintained at 95-96°C. After the dropping was completed, the reaction was continued at 95-96°C for 1.5 hours to complete the polymerization reaction.

[0032] S3, Post-treatment and sizing: The reactor was cooled to 75°C. The polymerization product was filtered through a 160 mesh filter bag. The filtered slurry was transferred to a sizing tank, and defoamer X-18C solution, ammonia, smoothing agent P22, defoamer X-10C, antistatic agent PN and bactericide were added in sequence. The stirring was started and stirred for 1.5 hours to make all the additives uniformly dispersed.

[0033] S4, Quality control: The final slurry was detected for saccharimeter concentration, viscosity and pH value.

[0034] Example 2: Raw material components (by mass parts): Butyl ester: 1250 parts by mass; methacrylic acid: 600 parts by mass; styrene: 580 parts by mass; methyl methacrylate: 75 parts by mass; process water: 6200 parts by mass; catalase: 1 part by mass; ammonium persulfate solution (concentration 1% (w / v)): 7 parts by mass; ammonium persulfate initiator (concentration 1% (w / v)): 9 parts by mass; sodium polyacrylate (dispersant): 65 parts by mass; polyvinyl alcohol (stabilizer): 10 parts by mass; mercaptoethanol (chain transfer agent solution): 2.5 parts by mass; sodium hydrosulfite formaldehyde (white lead solution): 1.5 parts by mass; polydimethylsiloxane (defoamer X-18C solution): 11 parts by mass; ammonia: 320 parts by mass; polyalkylene glycol (smoothing agent P22): 680 parts by mass; polydimethylsiloxane (defoamer X-10C): 15 parts by mass; quaternary ammonium salt (antistatic agent PN): 260 parts by mass; isothiazolinone (bactericide): 18 parts by mass.

[0035] Preparation steps: S1, Raw material preparation and premixing: In a mixing tank, butyl ester, methacrylic acid, styrene and methyl methacrylate were added in sequence. The stirring was started and mixed at the speed of 50 rpm for 45 minutes to form a monomer mixture.

[0036] S2, Enzyme catalyzed polymerization reaction (intelligent control): In a 15 cubic meter reactor, process water, sodium polyacrylate and polyvinyl alcohol were added. The stirring was started and the stirring speed was set to 45 rpm. The reactor was heated to reach the temperature of 95°C. When the temperature was stable, the online near-infrared spectrum sensor and the online viscosity sensor were started and connected to the intelligent control system. The following solutions were added by peristaltic pump at an initial drop rate of 5 parts by mass per minute: catalase, ammonium persulfate solution, ammonium persulfate initiator, mercaptoethanol and sodium sulfite formaldehyde. At the same time, 0.5% (w / v) hydrogen peroxide solution was slowly added by another peristaltic pump at a rate of 0.08 parts by mass per minute as the substrate of catalase.

[0037] During the whole drop process, the intelligent control system analyzed the online near-infrared spectrum data in real time to monitor the monomer conversion rate, monitored the slurry viscosity in real time, and monitored the pH value in the reactor in real time. When the system detected that the monomer conversion rate deviated from the preset range (e.g., less than 90%), the system dynamically adjusted the monomer drop rate (e.g., reduced to 4 parts by mass per minute) or the stirring speed (e.g., increased to 50 rpm); when the pH value in the reactor was detected to deviate from the preset range (e.g., less than 6.5), the intelligent control system automatically controlled the amount of ammonia water pumped in for adjustment. After the drop was completed, the reaction temperature was maintained at 95-96°C for 1.5 hours for continued incubation, and the polymerization reaction was completed.

[0038] S3, Post-treatment and sizing: The reactor was cooled to 75°C. The polymerization product was filtered through a 160 mesh filter bag. The filtered slurry was transferred to a sizing tank, and defoamer X-18C solution, ammonia water, smoothing agent P22, defoamer X-10C, antistatic agent PN and bactericide were added in sequence. The stirring was started and stirred for 1.5 hours to make all the additives uniformly dispersed.

[0039] S4, Quality control: The final slurry was detected for saccharimeter concentration, viscosity and pH value.

[0040] Comparative Example 1: Compared with Example 1, the difference is that 1 part by mass of laccase is not added in the polymerization reaction, and the rest is the same.

[0041] Comparative Example 2: Compared with Example 2, the difference is that the online near-infrared spectrum sensor and the online viscosity sensor are not started for real-time monitoring and dynamic adjustment during the polymerization process, and the rest is the same.

[0042] Comparative Example 3: Compared with Example 1, the difference is that the slurry after the polymerization reaction is not filtered and separated, and the rest is the same.

[0043] Experiment 1: Objective of the experiment: To evaluate the solids content of each sample slurry by indirectly obtaining the saccharimeter concentration through measuring the refractive index of the slurry.

[0044] Experimental procedure: Sample preparation: Transfer the prepared slurry samples (Example 1, Example 2, Comparative Example 1, Comparative Example 2, and Comparative Example 3) into clean, dry 50 mL beakers, respectively. Let the samples in all beakers stand at room temperature (25 ± 1 °C) for 30 minutes to ensure uniform internal temperature and to exclude air bubbles that might have been introduced during stirring or transferring.

[0045] Instrument calibration: Use a calibrated digital refractometer (Model: RX-5000 alpha). Before each measurement, first calibrate the instrument to zero point using deionized water (refractive index set to 0 Brix), then calibrate to two points using standard sucrose solutions of known concentrations (e.g., 10% Brix and 50% Brix) to ensure measurement accuracy.

[0046] Sample addition: Clean the prism surface of the refractometer, ensuring there are no residues, fingerprints, or scratches. Using a disposable dropper, take about 0.5 mL of the slurry sample and slowly, evenly add it to the prism surface of the refractometer. Ensure that the sample completely covers the prism surface and that there are no obvious air bubbles remaining inside.

[0047] Data reading: Close the cover plate of the refractometer and wait for the reading on the instrument display screen to stabilize. When the reading no longer jumps and shows a constant value, record the displayed saccharimeter concentration value (expressed in percentage Brix).

[0048] Repeated measurements and result calculation: Repeat the measurement 3 times for each sample, thoroughly clean the prism and re-add the sample between each measurement. Take the arithmetic mean of the 3 measurement results as the final saccharimeter concentration of the sample.

[0049] Cleaning and maintenance: Immediately after each measurement, thoroughly rinse the prism surface of the refractometer with deionized water, then gently dry it with soft, dust-free lens paper or a dedicated cleaning cloth to avoid scratching the prism surface, ready for the next use.

[0050] The experimental results are shown in Table 1.

[0051] Table 1: Saccharimeter concentrations of different slurry samples Sample No. Sugar amount concentration (%) Example 1 25.1 Example 2 25.0 Comparative Example 1 24.8 Comparative Example 2 24.9 Comparative Example 3 25.1 By analyzing the saccharimeter concentration data in Table 1, the slurries prepared by the present application (Example 1 and Example 2) exhibit excellent and stable properties in terms of solid content. The saccharimeter concentration of Example 1 is 25.1%, and that of Example 2 is 25.0%. These results indicate that in the polymerization system using laccase (Example 1) or catalase combined with intelligent control (Example 2), efficient conversion of monomers to polymers can be stably achieved, thereby obtaining high-concentration slurry products. The high solid content of the slurry is the basis for reducing transportation costs and improving use efficiency in downstream applications.

[0052] Comparative Example 1 did not add laccase in the polymerization reaction, and its saccharimeter concentration was 24.5%, lower than that of Example 1. This indicates that in the absence of enzyme preparation catalysis, the efficiency of the polymerization reaction may be reduced, resulting in partial monomers failing to fully polymerize, thereby affecting the effective solid content of the final slurry. Comparative Example 2 did not use an intelligent control system for real-time monitoring and dynamic adjustment. Its saccharimeter concentration was 24.8%, slightly lower than that of Example 2. This indicates that when key parameters (such as monomer drop rate, stirring speed, or pH value) in the polymerization reaction process are not accurately and real-time adjusted by the intelligent control system, the reaction conditions may deviate from the optimal state, thereby affecting the conversion efficiency of the monomers, resulting in a slight decrease in the solid content of the final slurry. The slurry of Comparative Example 3 was not filtered and separated, and its saccharimeter concentration was 25.0%, close to the value of Example 1. The slurry that has not been filtered and separated may contain unreacted monomers, oligomers, impurity particles formed during the polymerization process, or incompletely dissolved additives, etc. non-polymer components, which may also contribute to the refractive index. Therefore, although the saccharimeter concentration values are close, the product purity of Comparative Example 3 may be lower than that of Example 1.

[0053] Experiment 2: Purpose of the experiment: To evaluate the flowability of each sample slurry to verify the quality of each sample.

[0054] Experimental steps: Sample temperature control: Transfer the prepared slurry samples (Example 1, Example 2, Comparative Example 1, Comparative Example 2, and Comparative Example 3) into clean 500 mL beakers, respectively. Place the beakers in a constant temperature water bath to stabilize the sample temperature at 25.0±0.1℃. Before measurement, ensure that the sample is kept at this temperature for at least 30 minutes to eliminate the effect of temperature on viscosity.

[0055] Instrument preparation and selection: Use a rotational viscometer (Model: DV2T). According to the expected viscosity range of the slurry, select the appropriate rotor. The UL adapter is suitable for low viscosity samples to ensure measurement accuracy. According to the instrument instructions, install and calibrate the rotor. Set the rotation speed to 50 rpm.

[0056] Rotor Immersion and Bubble Elimination: The selected rotor is carefully and slowly immersed into the slurry sample, ensuring that the liquid surface reaches the marker line on the rotor shaft. This operation should avoid introducing air bubbles, as air bubbles can interfere with the viscosity measurement results. If there are air bubbles, the beaker should be gently tapped to allow them to escape.

[0057] Measurement Operation: Start the viscometer and wait for the readings to stabilize. When the viscosity value (in mPa-s) on the instrument display screen fluctuates within a certain time (e.g., 10 seconds) by no more than a set range (e.g., ±1 mPa-s), record the stable reading.

[0058] Repeated Measurements and Result Calculation: Each sample is measured 3 times. Between each measurement, the instrument can be briefly stopped, the rotor removed for cleaning, and then re-immersed in the sample for the next measurement to ensure the independence of the measurement conditions. The arithmetic mean of the 3 measurement results is taken as the final viscosity of the sample.

[0059] Cleaning and Maintenance: After each measurement is completed, the rotor is immediately removed from the sample and thoroughly cleaned with the appropriate solvent (e.g., deionized water) to remove all sample residues. Then, the rotor is dried with a soft, dust-free cleaning cloth to avoid scratches.

[0060] The experimental results are shown in Table 2.

[0061] Table 2: Viscosity of Different Slurry Samples Sample No. Viscosity (mPa-s) Example 1 185 Example 2 190 Comparative Example 1 230 Comparative Example 2 210 Comparative Example 3 250 According to the viscosity test data in Table 2, the viscosity of the slurry prepared in Example 1 (185 mPa-s) and Example 2 (190 mPa-s) is less than 200 mPa-s. This indicates that the formulation and preparation process of the present application can effectively control the rheological properties of the slurry, so that it still maintains good fluidity at high solid content. The low viscosity characteristics of the slurry help it to be operated conveniently in subsequent applications such as pumping, coating, spraying, etc., and can achieve uniform spreading.

[0062] Comparative Example 1 did not add enzyme preparation in the polymerization reaction, and the viscosity of the slurry was 230 mPa-s, which was significantly higher than Example 1. This can be due to the fact that the traditional initiation system has a wider molecular weight distribution of the polymerization product under the same reaction conditions, or there are more non-target products, thereby increasing the internal friction of the slurry system, showing higher viscosity. Comparative Example 2 did not use an intelligent control system for real-time monitoring and dynamic adjustment. The viscosity of the slurry was 210 mPa-s, which was higher than Example 2. This shows that when the intelligent control is lacking to accurately control the reaction parameters (such as monomer drop rate, stirring speed, etc.), the uniformity and controllability of the polymerization reaction decrease, which leads to uneven distribution of polymer molecular weight or structure, thereby affecting the rheological properties of the slurry, resulting in an increase in viscosity. The slurry of Comparative Example 3 was not filtered and separated, and its viscosity was as high as 250 mPa-s, which was the highest among all samples. This significantly shows that the impurities (such as unreacted monomers, oligomers, coarse particles or gel points) not removed have a serious negative impact on the rheological properties of the slurry. Impurities can increase the internal resistance of the slurry system, leading to a sharp increase in viscosity, and even cause problems such as equipment blockage, uneven coating, or poor spraying atomization, etc.

[0063] Experiment 3: Purpose of the experiment: to evaluate the pH of the slurry of each sample.

[0064] Experimental procedure: Sample preparation: Transfer the prepared slurry samples (Example 1, Example 2, Comparative Example 1, Comparative Example 2, and Comparative Example 3) into clean and dry 100 mL beakers, respectively. Before testing, the sample should be gently stirred for about 1 minute to ensure uniformity and no visible sedimentation or stratification, in order to obtain representative measurement results.

[0065] Instrument calibration: Use a calibrated high-precision pH meter (model: Five Easy Plus FP20). Before each measurement, strict two-point or three-point calibration must be performed. Usually, standard buffer solutions of pH 4.01 (acidic), pH 7.00 (neutral), and pH 10.00 (alkaline) are used for calibration to cover the possible pH range of the slurry, ensuring measurement accuracy and reliability. After calibration, wash the electrode thoroughly with deionized water and dry it.

[0066] Electrode immersion: Immerse the combined electrode of the pH meter completely into the slurry sample, ensuring that the electrode tip and sensitive membrane part are completely covered by the sample, and do not touch the bottom or side wall of the beaker, to avoid reading deviation caused by contact with solid surface. After immersion, the beaker can be gently shaken or the sample can be stirred at low speed using a magnetic stirrer to ensure that the electrode is in full contact with the sample and to speed up the reading stabilization.

[0067] Data Reading: Closely observe the reading on the pH meter display screen. Wait for the reading to stabilize, i.e., when the value on the display screen fluctuates no more than a set range (e.g., ±0.05 pH units) for a certain period of time (e.g., 15 seconds), record the stable reading. Recording data before the reading stabilizes can lead to errors.

[0068] Repeated Measurements and Result Calculation: Each sample should be measured at least 3 times. Between each measurement, the electrode must be thoroughly cleaned with deionized water and gently blotted dry with a blotting paper, then re-immersed in the sample for the next measurement, in order to eliminate the influence of the residue of the previous measurement. Take the arithmetic mean of the 3 measurement results as the final pH value of the sample, in order to improve the accuracy and reliability of the data.

[0069] Cleaning and Maintenance: After each measurement is completed, immediately thoroughly rinse the electrode with a large amount of deionized water to remove all sample residues. Then gently blot the water on the surface of the electrode with a soft blotting paper, avoiding the residues to dry on the electrode, which can cause the electrode to be contaminated or damaged. Put the electrode back into the dedicated storage solution to maintain the activity and life of the electrode membrane.

[0070] The experimental results are shown in Table 3.

[0071] Table 3: pH values of different slurry samples Sample No. pH value Example 1 7.0 Example 2 6.8 Comparative Example 1 5.5 Comparative Example 2 6.1 Comparative Example 3 6.5 The test results show that the pH values of the slurries prepared in Example 1 (pH 7.0) and Example 2 (pH 6.8) are both controlled within the range of 6.5-7.5, which represents an ideal state of neutral to weak alkaline. This indicates that the accurate control of the amount of ammonia water in the post-processing stage of the present application is effective, which can fully neutralize the acidic substances that may be generated in the polymerization process, so that the slurry is maintained at a stable and suitable pH value for storage and application.

[0072] Comparative Example 1 did not add enzyme preparation in the polymerization reaction, and the pH value was 5.5, which was significantly lower than Example 1. This strongly suggests that in the absence of enzyme catalysis, the traditional polymerization initiator system can produce more acidic by-products, and the reaction path lacks the ability of enzyme preparation to regulate pH under mild conditions, resulting in a higher overall acidity of the system. Too low pH value can accelerate the hydrolytic degradation of the slurry, affecting its long-term storage stability. Comparative Example 2 did not use an intelligent control system for real-time monitoring and dynamic adjustment. Its pH value was 6.1, lower than Example 2. This shows that when the intelligent control system is lacking for real-time monitoring and dynamic adjustment of the pH value during the polymerization process, it is difficult to neutralize the acidic substances generated during the polymerization process in a timely and accurate manner, resulting in the pH value of the final slurry deviating from the target range. The pH value of the slurry in Comparative Example 3 was 6.5 after the polymerization reaction was completed. Although the value is close to neutral, it is still slightly lower than Example 1. This shows that the slurry that has not been filtered and separated after the polymerization reaction contains acidic impurities formed during the polymerization process, unreacted monomers or oligomers, which can continue to affect the pH value of the slurry, making it unable to reach the best neutral range.

Claims

1. A high-concentration general-purpose slurry, characterized in that, The components include the following parts by mass: Butyl ester: 1200-1300 parts by weight; Methacrylic acid: 550-650 parts by weight; Styrene: 550-600 parts by weight; Methyl methacrylate: 70-80 parts by weight; Process water: 6000-6500 parts by weight; Enzyme preparation: 0.5-2 parts by weight; Ammonium persulfate solution: 6-8 parts by weight; Ammonium persulfate initiator: 8-10 parts by weight; Ammonia solution: 300-350 parts by weight; Additives: 1300-1500 parts by weight.

2. The high-concentration general-purpose slurry according to claim 1, characterized in that, The enzyme preparation is laccase or catalase.

3. The high-concentration general-purpose slurry according to claim 1, characterized in that, The concentrations of the ammonium persulfate solution and the ammonium persulfate initiator are both 1-5%.

4. The high-concentration general-purpose slurry according to claim 1, characterized in that, The process water is deionized water or purified water, and the ammonia water is an aqueous solution of ammonium hydroxide used to neutralize residual acidic substances.

5. The high-concentration general-purpose slurry according to claim 1, characterized in that, The adjuvants include; The dispersant composed of sodium polyacrylate is 60-70 parts by weight; The stabilizer, composed of polyvinyl alcohol, is 8-12 parts by weight; The chain transfer agent solution composed of mercaptoethanol is 2-3 parts by mass; The amount of sodium bisulfite formaldehyde solution is 1-2 parts by weight; The defoamer X-18C solution composed of polydimethylsiloxane is 10-12 parts by weight; The smoothing agent P22, composed of polyalkylene glycol or amino silicone oil, is in the form of 650-700 parts by weight. The defoamer X-10C, composed of polydimethylsiloxane, is present in a quantity of 12-18 parts by weight. The antistatic agent PN, composed of quaternary ammonium salt or polyethylene glycol ester, is 250-270 parts by weight; The bactericide composed of isothiazolinone is 15-20 parts by weight.

6. A method for preparing a high-concentration general-purpose slurry, used to prepare the high-concentration general-purpose slurry according to any one of claims 1-5, characterized in that, Includes the following steps: S1. Prepare the necessary measuring tools and equipment, and check the raw materials to ensure they meet the standard requirements; S2. In a mixing tank, add the monomer components according to the specified ratio and mix them to form a monomer mixture. S3. Add process water, dispersant and stabilizer to the reactor, set and maintain the polymerization reaction temperature, add superinitiator and auxiliary initiator dropwise under stirring conditions, and adjust according to the reaction process to ensure that the monomers react fully to generate polymer. S4. Cool and filter the polymer generated by the reaction, and add defoamer X-18C solution, ammonia, smoothing agent, defoamer X-10C, antistatic agent PN and bactericide in sequence, stir evenly to form the final slurry; S5. Test the various indicators of the final slurry and make adjustments based on the test results.

7. The method for preparing high-concentration general-purpose slurry according to claim 6, characterized in that, In step S2, the monomer components include butyl ester, methacrylic acid, styrene, and methyl methacrylate, and the mixing process lasts for 30-60 minutes.

8. The method for preparing high-concentration general-purpose slurry according to claim 6, characterized in that, In step S3, the polymerization reaction includes: The polymerization reaction temperature is 95-96℃, and the stirring speed is 45±5 rpm; The initiator added was ammonium persulfate solution, and the auxiliary initiators were ammonium persulfate initiator, chain transfer agent solution and styrax powder solution. The dropping rate was 3-8 parts by mass per minute.

9. The method for preparing high-concentration general-purpose slurry according to claim 6, characterized in that, In step S3, after adding the initiator and auxiliary initiator dropwise under stirring conditions, the reaction temperature is maintained for 1-3 hours to complete the polymerization reaction.

10. The method for preparing high-concentration general-purpose slurry according to claim 6, characterized in that, In step S4, the polymer generated by the reaction is cooled and filtered to a temperature of 70-80°C and filtered using a 150-170 mesh filter bag.

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