Anti-clogging polyurethane screen plate and method of making same

Abstract

The application discloses an anti-blocking polyurethane sieve plate and a preparation method thereof, and belongs to the technical field of sieve plate processing, and is used for solving the technical problems of easy blocking of sieve holes of the polyurethane sieve plate in the prior art and low hardness, poor wear resistance and poor high-temperature resistance of the traditional polyurethane sieve plate. The application comprises a sieve plate body, the top of the sieve plate body is provided with a downwardly recessed cavity, a plurality of wave-shaped grooves are arranged on the inner wall of the bottom of the cavity in an adjacent undulating manner, a plurality of sieve holes are formed in the bottom of the cavity, and the plurality of sieve holes are all circular truncated cone structures. The application is improved by optimizing the overall structure of the sieve holes and the sieve plate, the risk of blocking of the sieve holes by the sieved objects is reduced, the material of the polyurethane sieve plate is modified, and the hardness, wear resistance, high-temperature resistance and corrosion resistance of the polyurethane sieve plate are improved.

Description

Anti-clogging polyurethane sieve plate and its preparation method Technical Field

[0001] This invention relates to the field of sieve plate processing technology, specifically to anti-clogging polyurethane sieve plates and their preparation methods. Background Technology

[0002] Screen plates are devices used in material handling processes to screen, separate, and classify materials. They are widely used in industries such as mining, metallurgy, chemical, and building materials to screen solids and separate and classify raw materials according to different particle sizes. Due to the diversity of material properties and the uneven distribution of particle size, screen holes are often blocked, which in turn affects screening efficiency and production efficiency.

[0003] Existing screen plates are mostly made of metal materials, such as steel plates and wires. When screening acidic or alkaline materials, the surface of the screen plate is easily corroded and damaged, leading to structural changes and a shorter service life. Furthermore, traditional screen plates typically have through-holes with the same upper and lower diameters. During screening, irregularly shaped solids can easily enter these holes and become stuck, causing clogging. With advancements in materials science and technology, polyurethane materials are increasingly being used in screen plate manufacturing. Polyurethane possesses excellent elasticity, wear resistance, and corrosion resistance, making it a potential material choice for anti-clogging screen plates. However, existing polyurethane screen plates have low hardness, poor wear resistance, and poor high-temperature resistance. In high-temperature environments, they easily soften, causing structural changes, and clogging still occurs frequently.

[0004] To address this technical deficiency, a solution is proposed. Summary of the Invention

[0005] The purpose of this invention is to provide an anti-clogging polyurethane screen plate and its preparation method, which solves the technical problems of existing polyurethane screen plates where the screen holes easily get stuck with irregularly shaped objects being screened, leading to screen hole blockage, and the low hardness, poor wear resistance and high temperature resistance of traditional polyurethane screen plates.

[0006] The objective of this invention can be achieved through the following technical solutions:

[0007] The anti-clogging polyurethane screen plate includes a screen plate body. The top of the screen plate body is provided with a downwardly recessed cavity. The bottom inner wall of the cavity is provided with a plurality of adjacent undulating wave-shaped grooves, and the bottom of the cavity is provided with a plurality of screen holes, wherein the plurality of screen holes are all frustum-shaped structures.

[0008] The preparation method of the anti-clogging polyurethane sieve plate includes the following steps:

[0009] S1. 1H,1H,10H,10H-perfluoro-1,10-decanediol, diethoxysilane, and anhydrous ethanol were added to a three-necked flask and stirred. The temperature of the three-necked flask was raised to 55-65℃, and triethylamine was added to the three-necked flask. The reaction was maintained at this temperature for 3-5 hours. The post-processed intermediate I was obtained.

[0010] The principle of the synthesis reaction of intermediate I is as follows:

[0011]

[0012] S2. Add intermediate I and anhydrous ethanol to a three-necked flask and stir. Add 5 wt% ammonia to the three-necked flask, raise the temperature of the three-necked flask to 55-65℃, and keep the reaction at this temperature for 2-3 hours. The post-processed product is fluoropolymer.

[0013] The synthesis reaction principle of fluoropolymers is as follows:

[0014]

[0015] S3. Fluoropolymer, composite precursor, terephthalic diisocyanate, and N,N-dimethylformamide are added to a nitrogen-protected three-necked flask and stirred. After the solid in the flask is stirred and clarified, a catalyst is added to the three-necked flask. The temperature of the three-necked flask is raised to 85-95℃, and the reaction is stirred for 18-20 hours. Modified silica is added to the three-necked flask, and the reaction is maintained at the temperature for 3-5 hours. The post-treatment yields the composite polyurethane.

[0016] The synthesis reaction principle of composite polyurethane is as follows:

[0017]

[0018] In the formula:

[0019]

[0020]

[0021] It is modified silicon dioxide.

[0022] S4. Mix the composite polyurethane, styrene-butadiene rubber, and auxiliary additives evenly and add them to a twin-screw extruder. After melt extrusion, inject the mixture into a molding die, cool and solidify to obtain a polyurethane screen plate.

[0023] Furthermore, in step S1, the molar ratio of 1H,1H,10H,10H-perfluoro-1,10-decanediol and diethoxysilane is 1:2, the amount of anhydrous ethanol used is 4 times the weight of 1H,1H,10H,10H-perfluoro-1,10-decanediol, and the amount of triethylamine used is 0.1 times the amount of anhydrous ethanol. The post-processing operation includes: after the reaction is complete, keeping the three-necked flask at 55-65°C and distilling under reduced pressure until no liquid flows out, to obtain intermediate I.

[0024] Further, in step S2, the ratio of intermediate I, anhydrous ethanol, and 5wt% ammonia is 3g:12mL:4mL. The post-treatment operation includes: after the reaction is complete, the temperature of the three-necked flask is lowered to room temperature, 0.1M hydrochloric acid is added to the three-necked flask to adjust the pH of the system to 7, the temperature of the three-necked flask is raised to 55-65℃, the ethanol is removed by vacuum distillation, purified water and ethyl acetate are added to the three-necked flask, the mixture is stirred for 30-50 min, allowed to stand and separated, the organic phase is washed three times with purified water, anhydrous magnesium sulfate is added to the organic phase and dried for 4-6 h, filtered, the filtrate is transferred to a rotary evaporator, the water bath temperature is set to 60-70℃, and vacuum distillation is carried out until no liquid flows out to obtain fluoropolymer resin.

[0025] Furthermore, the preparation method of the composite precursor is as follows:

[0026] A1. Add p-hydroxydiphenyl ether, 9-chloro-1-nonanol, and anhydrous ethanol to a three-necked flask under nitrogen protection and mix thoroughly to obtain a mixture.

[0027] A2. Add sodium hydroxide and anhydrous ethanol to a three-necked flask under nitrogen protection and stir. Raise the temperature of the three-necked flask to 50-60℃ and add the mixture dropwise to the three-necked flask. After the addition is complete, raise the temperature of the three-necked flask to 85-95℃ and react for 10-12 hours to obtain the composite precursor.

[0028] The synthesis reaction principle of the complex precursor is as follows:

[0029]

[0030] Furthermore, in step A1, the ratio of p-hydroxydiphenyl ether, 9-chloro-1-nonanol, and anhydrous ethanol is 1.57 g: 1 g: 7 mL.

[0031] Further, in step A2, the ratio of sodium hydroxide, anhydrous ethanol, and the mixed solution is 2g:15mL:35g. The post-processing operation includes: after the reaction is completed, the temperature of the three-necked flask is lowered to room temperature, vacuum filtration is performed, the filter cake is washed with distilled water and dried, the filter cake is mixed with 1-butanol at a ratio of 1g:2.5mL, the mixture is heated and stirred until the filter cake is completely dissolved, the temperature is lowered to room temperature, a large amount of solid precipitates out, vacuum filtration is performed to obtain the filter cake, and the filter cake is placed in a drying oven at a temperature of 60-70℃ and dried to constant weight to obtain the composite precursor.

[0032] Furthermore, the preparation method of modified silica is as follows: nano silica, anhydrous ethanol and 4-aminobutyltriethoxysilane are added to a three-necked flask and ultrasonically dispersed for 40-60 min. The three-necked flask is fixed on an iron stand with mechanical stirring and stirred. The temperature of the three-necked flask is raised to 55-65℃. 5wt% sodium hydroxide solution is added to the three-necked flask and the reaction is kept at this temperature for 3-5 h. The modified silica is obtained after post-treatment.

[0033] Furthermore, the ratio of nano-silica, anhydrous ethanol, 4-aminobutyltriethoxysilane, and 5wt% sodium hydroxide solution is 3g:10g:2g:5g. The post-treatment operation includes: after the reaction is complete, the temperature of the three-necked flask is lowered to room temperature, the mixture is filtered, the filter cake is washed with purified water until neutral, and then the filter cake is transferred to a drying oven at 70-80℃ and dried to constant weight to obtain modified silica.

[0034] Furthermore, in step S3, the ratio of fluororesin, composite precursor, terephthalic diisocyanate, N,N-dimethylformamide, catalyst, and modified silica is 2.9g:1.4g:1g:22g:0.1g:2.5g. The catalyst is dibutyltin dilaurate. The post-treatment operation includes: after the reaction is complete, adding ethanol to a three-necked flask, stirring for 20-30 minutes, filtering under reduced pressure, washing the filter cake three times with ethanol, drying it under vacuum, and transferring the filter cake to a drying oven at 60-70℃ to dry to constant weight to obtain composite polyurethane.

[0035] Furthermore, in step S4, the ratio of composite polyurethane to auxiliary additives is 20g:5g:1g; the auxiliary additives are composed of dispersant, antioxidant, plasticizer, and antistatic agent in a ratio of 2g:1g:1g:1g, wherein the dispersant is one or more of barium stearate, zinc stearate, calcium stearate, and magnesium stearate; the antioxidant is one or more of antioxidant DPPD, antioxidant PPD, and antioxidant H; the plasticizer is one or more of dioctyl phthalate, diphthalate, and diisobutyl phthalate; and the antistatic agent is dodecyl dimethylamine acetone. The temperatures of the six temperature zones of the twin-screw extruder from the feed end to the discharge end are set sequentially to 260℃, 265℃, 265℃, 265℃, 270℃, and 270℃, and the spindle speed of the twin-screw extruder is 18r / min.

[0036] The present invention has the following beneficial effects:

[0037] 1. The polyurethane screen plate of this invention, through the cooperation of the screen plate body, the corrugated groove and the screen holes, utilizes the corrugated groove set at the bottom of the top cavity of the screen plate body. As the screen plate body reciprocates along its length, during the screening process of solids in the screen plate cavity, the screened solids are thrown upwards along the arc surface of the corrugated groove and separated from the screen plate, and fall downwards under the action of gravity. However, the weight of the larger-diameter screened solids is heavier than that of the smaller-diameter solids. Under the action of inertia, the larger-diameter screened solids are thrown upwards to a greater height than the smaller-diameter screened solids, thus making the larger-diameter solids "float" above the screened solids, which is conducive to separating the larger-diameter screened solids from the smaller-diameter screened solids and improving the screening rate. Compared with the traditional screen holes with the same upper and lower aperture, the screen holes of this invention are funnel-shaped with a smaller upper aperture and a larger lower aperture. For irregularly shaped screened solids, as long as they pass through the top of the screen hole and enter the inner side of the screen hole, the large space below the screen hole can ensure that they fall smoothly and separate from the screen plate, avoiding blockage.

[0038] 2. In the preparation process of the polyurethane sieve plate of the present invention, intermediate I is prepared by reacting 1H,1H,10H,10H-perfluoro-1,10-decanediol and diethoxysilane under the catalysis of triethylamine, where the siloxane bond on diethoxysilane breaks and reacts with the hydroxyl group on 1H,1H,10H,10H-perfluoro-1,10-decanediol. Under alkaline aqueous conditions, the siloxane bonds at both ends of intermediate I break, undergoing a condensation reaction to prepare a fluororesin. Hydroxydiphenyl ether undergoes a substitution addition reaction with 9-chloro-1-nonanol under alkaline conditions to generate a composite precursor with a long linear chain structure. The fluororesin, the composite precursor, and terephthalic diisocyanate react, with the molar amount of terephthalic diisocyanate controlled by... A polyurethane with isocyanate-terminated ends is generated. The polyurethane reacts with the active functional groups on modified silica to prepare a composite polyurethane. The aromatic rings and long straight-chain structures contained in the composite precursor can increase the aromatic ring content of the polyurethane material, thereby improving the heat resistance of the polyurethane material. At the same time, the introduction of long straight-chain structures increases the material's flowability and moldability, thus improving the mechanical properties of the polyurethane material. The fluoropolymer contains long polycarbonate segments, and the fluorine atoms in the polycarbonate segments are inert and have high heat resistance and wear resistance. By controlling the ratio of fluoropolymer to composite precursor, the interaction between the material and chemical substances can be reduced, thereby improving the material's corrosion resistance, high temperature resistance, and wear resistance.

[0039] 3. In the preparation process of the polyurethane sieve plate of the present invention, the siloxane bonds on 4-aminobutyltriethoxysilane are hydrolyzed under alkaline conditions and then react with the active functional groups on the surface of nano-silica. Modified silica is prepared by modifying the silica surface with 4-aminobutyltriethoxysilane. The 4-aminobutyltriethoxysilane modified on the silica surface can promote the uniform dispersion of silica in the reaction system, while multiple amino groups on its surface can react with isocyanate groups, improving the crosslinking degree of the composite polyurethane, thereby improving the heat resistance and surface hardness of the composite polyurethane material, and thus improving the overall performance of the polyurethane. The wear resistance of polyurethane sieves improves their dimensional stability, making them more resistant to deformation and shrinkage. Nano-silica has a very large specific surface area and is a relatively chemically stable material with good resistance to many common chemicals. The extremely small size of nano-silica particles gives them more surface area within the material, allowing them to interact more with chemicals in the surrounding environment to form a physical barrier that prevents external chemicals from penetrating into the polyurethane material, thereby further improving the chemical resistance of the polyurethane sieve. Attached Figure Description

[0040] 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.

[0041] Figure 1 is a three-dimensional structural diagram of the polyurethane sieve plate in this invention;

[0042] Figure 2 is a schematic diagram of the front cross-sectional structure of the polyester sieve plate in this invention.

[0043] In the diagram: 100, sieve plate body; 200, wavy groove; 300, sieve hole. Detailed Implementation

[0044] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0045] Example 1

[0046] Please refer to Figures 1-2. This embodiment provides an anti-clogging polyurethane screen plate, including a screen plate body 100. The top of the screen plate body 100 is provided with a downwardly recessed cavity. The bottom inner wall of the cavity is provided with a plurality of adjacent undulating wave-shaped grooves 200, and the bottom of the cavity is provided with a plurality of screen holes 300, wherein the plurality of screen holes 300 are all frustum-shaped structures.

[0047] The sieve hole 300 is a conical structure with a top opening area larger than the bottom opening area. For irregularly shaped solids, as long as they pass through the top of the sieve hole and enter the inner side of the sieve hole, the large space below the sieve hole can ensure that they fall smoothly and separate from the sieve plate, thus avoiding blockage.

[0048] Example 2

[0049] Please refer to Figures 1-2. This embodiment provides a method for preparing an anti-clogging polyurethane sieve plate, including the following steps:

[0050] S1. Preparation of fluororesin

[0051] Weigh out 46.2 g of 1H,1H,10H,10H-perfluoro-1,10-decanediol, 24.0 g of diethoxysilane, and 184.8 g of anhydrous ethanol and add them to a three-necked flask. Stir the mixture and raise the temperature of the three-necked flask to 55°C. Add 18.5 g of triethylamine to the three-necked flask and maintain the temperature for 3-5 hours. Keep the three-necked flask at 55°C and distill under reduced pressure until no liquid flows out to obtain intermediate I.

[0052] Weigh 60g of intermediate I and 240mL of anhydrous ethanol into a three-necked flask and stir. Add 80mL of 5wt% ammonia water to the three-necked flask, raise the temperature of the three-necked flask to 55℃, and maintain the temperature for 2h. Lower the temperature of the three-necked flask to room temperature, add 0.1M hydrochloric acid to adjust the pH of the system to 7, raise the temperature of the three-necked flask to 55℃, remove the ethanol under reduced pressure, add 200mL of purified water and 240mL of ethyl acetate to the three-necked flask, stir for 30min, allow to stand and separate the liquids. Wash the organic phase three times with purified water, add 50g of anhydrous magnesium sulfate to the organic phase and dry for 4h, filter, transfer the filtrate to a rotary evaporator, set the water bath temperature to 60℃, and distill under reduced pressure until no liquid flows out to obtain fluoropolymer resin.

[0053] S2. Preparation of composite precursors

[0054] Weigh out 78.5 g of p-hydroxydiphenyl ether, 50 g of 9-chloro-1-nonanol, and 350 mL of anhydrous ethanol and add them to a three-necked flask under nitrogen protection. Mix well to obtain a mixture.

[0055] Weigh 20g of sodium hydroxide and 150mL of anhydrous ethanol and add them to a three-necked flask under nitrogen protection. Stir the mixture and raise the temperature of the flask to 50℃. Add 350mL of the mixture dropwise to the flask. After the addition is complete, raise the temperature of the flask to 85℃ and react for 10h. Then, lower the temperature of the flask to room temperature and filter under reduced pressure. Wash the filter cake with distilled water and dry it under vacuum. Mix the filter cake with 1-butanol at a ratio of 1g:2.5mL and heat and stir until the filter cake is completely dissolved. Cool to room temperature, and a large amount of solid will precipitate. Filter under reduced pressure to obtain the filter cake. Place the filter cake in a drying oven at 60℃ and dry it to constant weight to obtain the composite precursor.

[0056] S3, Preparation of modified silica

[0057] Weigh out 30g of nano-silica, 100g of anhydrous ethanol and 20g of 4-aminobutyltriethoxysilane and add them to a three-necked flask. Disperse the mixture by sonication for 40min. Fix the three-necked flask on an iron stand with a mechanical stirrer and stir. Raise the temperature of the three-necked flask to 55℃ and add 50g of 5wt% sodium hydroxide solution to the three-necked flask. Keep the reaction at this temperature for 3h. Lower the temperature of the three-necked flask to room temperature and filter. Wash the filter cake with purified water until neutral and transfer the filter cake to a drying oven at 70℃ to dry to constant weight to obtain modified silica.

[0058] S4. Preparation of composite polyurethane

[0059] Weigh out 58g of fluoropolymer, 28g of composite precursor, 20g of terephthalic diisocyanate, and 440g of N,N-dimethylformamide and add them to a three-necked flask under nitrogen protection. Stir until the solid in the flask is clear. Add 2g of dibutyltin dilaurate to the three-necked flask. Raise the temperature of the three-necked flask to 85℃ and stir for 18h. Add 50g of modified silica to the three-necked flask and keep it at the temperature for 3h. Lower the temperature of the three-necked flask to room temperature and add 500mL of ethanol. Stir for 20min and filter under reduced pressure. Wash the filter cake three times with ethanol and dry it under vacuum. Transfer the filter cake to a drying oven at 60℃ and dry it to constant weight to obtain composite polyurethane.

[0060] S5. Preparation of polyurethane sieve plates

[0061] Weigh out 200g of composite polyurethane, 50g of styrene-butadiene rubber, 4g of barium stearate, 2g of antioxidant DPPD, 2g of dioctyl phthalate, and 2g of dodecyl dimethylamine acetone, mix them evenly, and add them to a twin-screw extruder. Set the temperatures of the six temperature zones of the twin-screw extruder from the feed end to the discharge end to 260℃, 265℃, 265℃, 265℃, 270℃, and 270℃ respectively. The spindle speed of the twin-screw extruder is 18r / min. After melt extrusion, inject the mixture into the molding die, cool and solidify, and then demold to obtain the polyurethane screen plate as provided in Example 1.

[0062] Example 3

[0063] Please refer to Figures 1-2. This embodiment provides a method for preparing an anti-clogging polyurethane sieve plate, including the following steps:

[0064] S1. Preparation of fluororesin

[0065] Weigh out 46.2 g of 1H,1H,10H,10H-perfluoro-1,10-decanediol, 24.0 g of diethoxysilane, and 184.8 g of anhydrous ethanol and add them to a three-necked flask. Stir the mixture and raise the temperature of the three-necked flask to 60 °C. Add 18.5 g of triethylamine to the three-necked flask and maintain the temperature for 4 h. Then, keep the three-necked flask at 60 °C and distill under reduced pressure until no liquid flows out to obtain intermediate I.

[0066] Weigh 60g of intermediate I and 240mL of anhydrous ethanol into a three-necked flask and stir. Add 80mL of 5wt% ammonia water to the three-necked flask, raise the temperature of the three-necked flask to 60℃, and maintain the temperature for 2.5h. Lower the temperature of the three-necked flask to room temperature, add 0.1M hydrochloric acid to adjust the pH of the system to 7, raise the temperature of the three-necked flask to 60℃, remove the ethanol under reduced pressure, add 200mL of purified water and 240mL of ethyl acetate to the three-necked flask, stir for 40min, let stand and separate the liquids. Wash the organic phase three times with purified water, add 50g of anhydrous magnesium sulfate to the organic phase and dry for 5h, filter, transfer the filtrate to a rotary evaporator, set the water bath temperature to 65℃, and distill under reduced pressure until no liquid flows out to obtain fluoropolymer resin.

[0067] S2. Preparation of composite precursors

[0068] Weigh out 78.5 g of p-hydroxydiphenyl ether, 50 g of 9-chloro-1-nonanol, and 350 mL of anhydrous ethanol and add them to a three-necked flask under nitrogen protection. Mix well to obtain a mixture.

[0069] Weigh 20g of sodium hydroxide and 150mL of anhydrous ethanol and add them to a three-necked flask under nitrogen protection. Stir the mixture and raise the temperature of the flask to 55℃. Add 350mL of the mixture dropwise to the flask. After the addition is complete, raise the temperature of the flask to 90℃ and react for 11 hours. Then, lower the temperature of the flask to room temperature and filter under reduced pressure. Wash the filter cake with distilled water and dry it under vacuum. Mix the filter cake with 1-butanol at a ratio of 1g:2.5mL and heat and stir until the filter cake is completely dissolved. Cool to room temperature, and a large amount of solid will precipitate. Filter under reduced pressure to obtain the filter cake. Place the filter cake in a drying oven at 65℃ and dry it to constant weight to obtain the composite precursor.

[0070] S3, Preparation of modified silica

[0071] Weigh out 30g of nano-silica, 100g of anhydrous ethanol and 20g of 4-aminobutyltriethoxysilane and add them to a three-necked flask. Disperse the mixture by sonication for 50min. Fix the three-necked flask on an iron stand with a mechanical stirrer and stir. Raise the temperature of the three-necked flask to 60℃ and add 50g of 5wt% sodium hydroxide solution to the three-necked flask. Keep the reaction at this temperature for 4h. Lower the temperature of the three-necked flask to room temperature and filter. Wash the filter cake with purified water until neutral and then transfer the filter cake to a drying oven at 75℃ to dry to constant weight to obtain modified silica.

[0072] S4. Preparation of composite polyurethane

[0073] Weigh out 58g of fluoropolymer, 28g of composite precursor, 20g of terephthalic diisocyanate, and 440g of N,N-dimethylformamide and add them to a three-necked flask under nitrogen protection. Stir until the solid in the flask is clear. Add 2g of dibutyltin dilaurate to the three-necked flask. Raise the temperature of the three-necked flask to 90℃ and stir for 19h. Add 50g of modified silica to the three-necked flask and keep it at the temperature for 4h. Lower the temperature of the three-necked flask to room temperature and add 500mL of ethanol. Stir for 25min and filter under reduced pressure. Wash the filter cake three times with ethanol and dry it under vacuum. Transfer the filter cake to a drying oven at 65℃ and dry it to constant weight to obtain composite polyurethane.

[0074] S5. Preparation of polyurethane sieve plates

[0075] Weigh out 200g of composite polyurethane, 50g of styrene-butadiene rubber, 4g of zinc stearate, 2g of antioxidant PPD, 2g of diphthalate, and 2g of anti-dodecyl dimethylamine acetone, mix them evenly, and add them to a twin-screw extruder. Set the temperatures of the six temperature zones of the twin-screw extruder from the feed end to the discharge end to 260℃, 265℃, 265℃, 265℃, 270℃, and 270℃ respectively. The spindle speed of the twin-screw extruder is 18r / min. After melt extrusion, inject the mixture into the molding die, cool and solidify, and then demold to obtain the polyurethane screen plate as provided in Example 1.

[0076] Example 4

[0077] Please refer to Figures 1-2. This embodiment provides a method for preparing an anti-clogging polyurethane sieve plate, including the following steps:

[0078] S1. Preparation of fluororesin

[0079] Weigh out 46.2 g of 1H,1H,10H,10H-perfluoro-1,10-decanediol, 24.0 g of diethoxysilane, and 184.8 g of anhydrous ethanol and add them to a three-necked flask. Stir the mixture and raise the temperature of the three-necked flask to 65°C. Add 18.5 g of triethylamine to the three-necked flask and maintain the temperature for 5 h. Then, keep the three-necked flask at 65°C and distill under reduced pressure until no liquid flows out to obtain intermediate I.

[0080] Weigh 60 g of intermediate I and 240 mL of anhydrous ethanol into a three-necked flask and stir. Add 80 mL of 5 wt% ammonia water to the three-necked flask, raise the temperature of the three-necked flask to 65 °C, and maintain the temperature for 3 h. Lower the temperature of the three-necked flask to room temperature, add 0.1 M hydrochloric acid to adjust the pH of the system to 7, raise the temperature of the three-necked flask to 65 °C, remove the ethanol under reduced pressure, add 200 mL of purified water and 240 mL of ethyl acetate to the three-necked flask, stir for 50 min, allow to stand and separate the liquids. Wash the organic phase three times with purified water, add 50 g of anhydrous magnesium sulfate to the organic phase and dry for 6 h, filter, transfer the filtrate to a rotary evaporator, set the water bath temperature to 70 °C, and distill under reduced pressure until no liquid flows out to obtain fluoropolymer resin.

[0081] S2. Preparation of composite precursors

[0082] Weigh out 78.5 g of p-hydroxydiphenyl ether, 50 g of 9-chloro-1-nonanol, and 350 mL of anhydrous ethanol and add them to a three-necked flask under nitrogen protection. Mix well to obtain a mixture.

[0083] Weigh 20g of sodium hydroxide and 150mL of anhydrous ethanol and add them to a three-necked flask under nitrogen protection. Stir the mixture and raise the temperature of the flask to 60℃. Add 350mL of the mixture dropwise to the flask. After the addition is complete, raise the temperature of the flask to 95℃ and react for 12h. Then, lower the temperature of the flask to room temperature and filter under reduced pressure. Wash the filter cake with distilled water and dry it under vacuum. Mix the filter cake with 1-butanol at a ratio of 1g:2.5mL and heat and stir until the filter cake is completely dissolved. Cool to room temperature, and a large amount of solid will precipitate. Filter under reduced pressure to obtain the filter cake. Place the filter cake in a drying oven at 70℃ and dry it to constant weight to obtain the composite precursor.

[0084] S3, Preparation of modified silica

[0085] Weigh out 30g of nano-silica, 100g of anhydrous ethanol and 20g of 4-aminobutyltriethoxysilane and add them to a three-necked flask. Disperse the mixture by sonication for 60min. Fix the three-necked flask on an iron stand with a mechanical stirrer and stir. Raise the temperature of the three-necked flask to 65℃ and add 50g of 5wt% sodium hydroxide solution to the three-necked flask. Keep the reaction at this temperature for 5h. Lower the temperature of the three-necked flask to room temperature and filter. Wash the filter cake with purified water until neutral and then transfer the filter cake to a drying oven at 80℃ to dry to constant weight to obtain modified silica.

[0086] S4. Preparation of composite polyurethane

[0087] Weigh out 58g of fluoropolymer, 28g of composite precursor, 20g of terephthalic diisocyanate, and 440g of N,N-dimethylformamide and add them to a three-necked flask under nitrogen protection. Stir until the solid in the flask is clear. Add 2g of dibutyltin dilaurate to the three-necked flask. Raise the temperature of the three-necked flask to 85-95℃ and stir for 20h. Add 50g of modified silica to the three-necked flask and keep it at the temperature for 5h. Lower the temperature of the three-necked flask to room temperature and add 500mL of ethanol. Stir for 30min and filter under reduced pressure. Wash the filter cake three times with ethanol and dry it under vacuum. Transfer the filter cake to a drying oven at 70℃ and dry it to constant weight to obtain composite polyurethane.

[0088] S5. Preparation of polyurethane sieve plates

[0089] Weigh out 200g of composite polyurethane, 50g of styrene-butadiene rubber, 2g of calcium stearate, 2g of magnesium stearate, 2g of antioxidant H, 2g of diisobutyl phthalate, and 2g of dodecyl dimethylamine acetone. Mix them evenly and add them to a twin-screw extruder. Set the temperatures of the six temperature zones of the twin-screw extruder from the feed end to the discharge end to 260℃, 265℃, 265℃, 265℃, 270℃, and 270℃ respectively. The spindle speed of the twin-screw extruder is 18r / min. After melt extrusion, inject the mixture into the molding die, cool and solidify, and then demold to obtain the polyurethane screen plate as provided in Example 1.

[0090] Comparative Example 1

[0091] The difference between this comparative example and Example 2 is that step S1 is omitted and fluoropolymer is not added in step S4.

[0092] Comparative Example 2

[0093] The difference between this comparative example and Example 2 is that step S2 is omitted, and the composite precursor in step S4 is replaced by an equimolar amount of p-hydroxydiphenyl ether.

[0094] Comparative Example 3

[0095] The difference between this comparative example and Example 2 is that step S3 is omitted, and the modified silica in step S4 is replaced by an equal amount of nano-silica.

[0096] Performance testing:

[0097] The hardness, wear resistance, corrosion resistance, and high-temperature resistance of the polyurethane sieve plates prepared in Examples 2-4 and Comparative Examples 1-3 were tested. Hardness was determined according to standard GB / T 5766-2007 "Rockwell Hardness Test Method for Friction Materials". Wear resistance was tested according to standard GB / T 18301-2012 "Abrasion Resistance Test Method for Refractory Materials at Room Temperature". Corrosion resistance and high-temperature resistance were determined according to standard HG / T 4087-2009 "Corrosion-resistant Composite Pipes of Plastic Alloys". Specific test results are shown in the table below:

[0098]

[0099]

[0100] Data Analysis:

[0101] Comparative analysis of the data in the table above shows that the Rockwell hardness of the polyurethane sieve plate prepared by this invention reaches 58.7 HRC, and the wear is reduced to 0.03 mm. -3 In a 30wt% sulfuric acid environment, the corrosivity is reduced to 0.005 g / m³. 2 The corrosion rate in a 40 wt% sodium hydroxide solution decreased to 0.005 g / m³. 2 Its Vicat softening temperature reaches 215°C, and the test data of the sieve plate prepared in the embodiments of the present invention are all better than those of the comparative example, indicating that the polyurethane sieve plate prepared by the present invention has high hardness, wear resistance, high temperature resistance and good corrosion resistance.

[0102] The above description is merely an example and illustration of the structure of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described, or use similar methods to replace them, as long as they do not deviate from the structure of the invention or exceed the scope defined in the claims, all of which should fall within the protection scope of the present invention.

[0103] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0104] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to any specific implementation. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A method for preparing an anti-clogging polyurethane sieve plate, characterized in that, Includes the following steps: S1. Add 1H,1H,10H,10H-perfluoro-1,10-decanediol, diethoxysilane, and anhydrous ethanol to a three-necked flask and stir. Raise the temperature of the three-necked flask to 55-65℃ and add triethylamine. Maintain the reaction temperature for 3-5 hours, then perform post-treatment to obtain intermediate I. S2. Add intermediate I and anhydrous ethanol to a three-necked flask and stir. Add 5wt% ammonia water to the three-necked flask and raise the temperature of the three-necked flask to 55-65℃. Maintain the reaction temperature for 2-3 hours, then perform post-treatment to obtain a fluoropolymer. S3. Add the fluoropolymer, the composite precursor, and terephthalic acid... Ester and N,N-dimethylformamide were added to a nitrogen-protected three-necked flask and stirred. After the solid in the flask became clear, a catalyst was added to the three-necked flask, and the temperature of the three-necked flask was raised to 85-95℃. The mixture was stirred and reacted for 18-20 hours. Modified silica was added to the three-necked flask, and the mixture was kept at this temperature for 3-5 hours. The resulting product was then processed to obtain a composite polyurethane. S4. The composite polyurethane, styrene-butadiene rubber, and auxiliary additives were mixed evenly and added to a twin-screw extruder. After melt extrusion, the mixture was injected into a molding die and cooled to solidify, resulting in a polyurethane sieve plate. The polyurethane sieve plate includes a sieve plate body (100). The top of the sieve plate body (100) is provided with a downwardly recessed cavity, and the bottom inner wall of the cavity is provided with a plurality of adjacent undulating wavy grooves (200), and the bottom of the cavity is provided with a plurality of sieve holes (300), wherein the plurality of sieve holes (300) are all frustum-shaped structures; the preparation method of the composite precursor is as follows: A1, p-hydroxydiphenyl ether, 9-chloro-1-nonanol and anhydrous ethanol are added to a three-necked flask under nitrogen protection and mixed evenly to obtain a mixture; A2, sodium hydroxide and anhydrous ethanol are added to a three-necked flask under nitrogen protection and stirred, and the temperature of the three-necked flask is raised to 5 At 0-60℃, a mixed solution was added dropwise to a three-necked flask. After the addition was complete, the temperature of the three-necked flask was raised to 85-95℃ and reacted for 10-12 hours to obtain a composite precursor. The preparation method of modified silica is as follows: nano silica, anhydrous ethanol and 4-aminobutyltriethoxysilane were added to a three-necked flask and ultrasonically dispersed for 40-60 minutes. The three-necked flask was fixed on an iron stand with a mechanical stirrer and stirred. The temperature of the three-necked flask was raised to 55-65℃, and 5wt% sodium hydroxide solution was added to the three-necked flask. The reaction was kept at this temperature for 3-5 hours. After post-treatment, modified silica was obtained.

2. The method for preparing the anti-clogging polyurethane sieve plate according to claim 1, characterized in that, In step S1, the molar ratio of 1H,1H,10H,10H-perfluoro-1,10-decanediol and diethoxysilane is 1:2, the amount of anhydrous ethanol used is 4 times the weight of 1H,1H,10H,10H-perfluoro-1,10-decanediol, and the amount of triethylamine used is 0.1 times the amount of anhydrous ethanol. In step S2, the ratio of intermediate I, anhydrous ethanol, and 5wt% ammonia is 3g:12mL:4mL.

3. The method for preparing the anti-clogging polyurethane sieve plate according to claim 1, characterized in that, In step A1, the ratio of p-hydroxydiphenyl ether, 9-chloro-1-nonanol, and anhydrous ethanol is 1.57 g: 1 g: 7 mL; in step A2, the ratio of sodium hydroxide, anhydrous ethanol, and the mixture is 2 g: 15 mL: 35 g.

4. The method for preparing the anti-clogging polyurethane sieve plate according to claim 1, characterized in that, The ratio of nano-silica, anhydrous ethanol, 4-aminobutyltriethoxysilane, and 5wt% sodium hydroxide solution is 3g:10g:2g:5g. The post-treatment includes: after the reaction is complete, the temperature of the three-necked flask is lowered to room temperature, the mixture is filtered, the filter cake is washed with purified water until neutral, and then the filter cake is transferred to a drying oven at 70-80℃ and dried to constant weight to obtain modified silica.

5. The method for preparing the anti-clogging polyurethane sieve plate according to claim 1, characterized in that, In step S3, the ratio of fluororesin, composite precursor, terephthalic diisocyanate, N,N-dimethylformamide, catalyst and modified silica is 2.9g:1.4g:1g:22g:0.1g:2.5g, and the catalyst is dibutyltin dilaurate.

6. The method for preparing the anti-clogging polyurethane sieve plate according to claim 2, characterized in that, In step S4, the ratio of composite polyurethane to auxiliary additives is 20g:5g:1g; the auxiliary additives consist of dispersant, antioxidant, plasticizer, and antistatic agent in a ratio of 2g:1g:1g:1g, wherein the dispersant is one or more of barium stearate, zinc stearate, calcium stearate, and magnesium stearate, the antioxidant is DPPD, the plasticizer is one or more of dioctyl phthalate, diphthalate, and diisodecyl phthalate, and the antistatic agent is dodecyl dimethylamine acetone. The temperatures of the six temperature zones of the twin-screw extruder from the feed end to the discharge end are set sequentially to 260℃, 265℃, 265℃, 265℃, 270℃, and 270℃, and the spindle speed of the twin-screw extruder is 18r / min.

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