A high-precision wear-resistant filter material coated with a nano coating and a preparation method thereof

Abstract

The application relates to the technical field of filter materials, in particular to a high-precision wear-resistant filter material coated with a nano coating and a preparation method thereof. A non-woven fabric is used as a filter support layer, a nano silicon sol dispersion solution is coated on the surface of the filter support layer, heat setting is carried out, an upper filter surface layer is formed, the filter material is obtained, the prepared upper filter surface layer has a three-dimensional structure, the average pore diameter of the upper filter surface layer is controlled to be 5-10 mu m, the nano silicon sol dispersion solution is obtained by mixing nano silicon sol, PTFE emulsion, acrylic emulsion, fluorocarbon surfactant, silane coupling agent, film forming agent and deionized water, the self-repairing polyurethane emulsion is used as the film forming agent, the polytetrahydrofuran and isophorone diisocyanate are used as raw materials to synthesize a prepolymer, the 2,2-dimethylol propionic acid is used as a hydrophilic chain extender, and the modified nano zinc oxide and glycyl glycine methyl ester are used as end-capping agents.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of filter materials, and particularly relates to a high-precision wear-resistant filter material coated with a nano coating and a preparation method thereof. BACKGROUND

[0002] In modern industrial production, air filtration and industrial waste gas treatment are important issues. With the development of science and technology, the performance requirements for filter materials are becoming increasingly stringent. Traditional filter materials have limitations in filtration precision due to problems such as uneven pore size distribution and single material structure.

[0003] In addition, ordinary filter materials have poor wear resistance and antibacterial properties, and cannot withstand frequent mechanical friction and airflow impact for a long time. They are prone to damage in a short period of time, and need to be frequently replaced. This not only increases costs but also leads to unstable operation of the filtration system, affecting the continuity of production.

[0004] For example, patent CN202110605769.6 discloses a composite filter material and a preparation method thereof. The needle-punched felt is immersed in aramid nanofiber dispersion liquid and dried to obtain the composite filter material. Although the mechanical properties and filtration performance of the filter material are improved, a three-dimensional network structure cannot be formed inside the filter material, and it is difficult to ensure that the flue gas concentration is discharged at 10 mg / Nm 3 For example, patent CN202310476580.0 discloses a high-wear-resistant and high-fold-resistant glass fiber composite filter material and a preparation method thereof. The composite impregnating liquid is dispersed into the glass fiber composite filter material through the impregnation-pressing process and dried to obtain the composite filter material. Although the wear resistance and fold resistance of the glass fiber composite filter material are improved, the filtration effect and antibacterial properties of the material are not greatly improved. SUMMARY

[0005] The application aims to provide a high-precision wear-resistant filter material coated with a nano coating and a preparation method thereof to solve the problems in the prior art.

[0006] To solve the above technical problems, the application provides the following technical scheme.

[0007] A preparation method of a high-precision wear-resistant filter material coated with a nano coating, comprising the following steps:

[0008] S1: mixing nano silicon sol, PTFE emulsion, acrylic emulsion, fluorocarbon surfactant, silane coupling agent, film-forming agent and deionized water to obtain a nano silicon sol dispersion liquid;

[0009] S2: coating the nano silicon sol dispersion liquid on the surface of a filter support layer made of non-woven fabric, and heat setting to form an upper filter surface layer, thereby obtaining a high-precision wear-resistant filter material coated with a nano coating.

[0010] Further, the working conditions of heat setting are as follows: the temperature of 1-3 zones is 160-180°C, the temperature of 4-6 zones is 180-200°C, the temperature of 6-8 zones is 200-220°C, and the speed is 5-7 m / min.

[0011] Further, the composition of the nano-silica sol dispersion liquid is as follows in mass fraction: 10-30 parts of nano-silica sol, 20-40 parts of PTFE emulsion, 5-20 parts of acrylic emulsion, 0.5-2 parts of fluorocarbon surfactant, 0.5-2 parts of silane coupling agent, 0.5-2 parts of film forming agent, and 10-60 parts of deionized water.

[0012] Further, the filter support layer is one or several composite non-woven fabrics selected from PPS non-woven fabric, aramid non-woven fabric, polyester non-woven fabric, PTFE non-woven fabric, and glass fiber non-woven fabric.

[0013] Further, the filter support layer has a grammage of 400-800 g / m 2 , and a thickness of 1-3 mm; the upper filter surface layer has a pore size of 5-10 µm, and a thickness of 0.5-2 µm.

[0014] Further, the nano-silica sol has a particle size of 8-15 nm.

[0015] Further, the film forming agent is one of polyurethane, acrylic acid, and epoxy resin.

[0016] Further, the film forming agent is a self-repairing polyurethane emulsion, which is prepared by the following steps:

[0017] Under a nitrogen atmosphere, polytetrahydrofuran, isophorone diisocyanate, and dibutyltin dilaurate are mixed, and then incubated at 78-82°C for 40-60 min. A mixed solution of 2,2-dimethylol propionic acid and N,N-dimethylformamide is added, and the incubation is continued for 80-100 min. A mixed solution of modified nano-zinc oxide and N,N-dimethylformamide is added, and the temperature is lowered to 35-40°C. Triethylamine is added, and incubated for 40-60 min. A mixed solution of glycylglycine methyl ester and N,N-dimethylformamide is added, and incubated in an ice water bath for 2-3 h. Deionized water is added for emulsification for 1-2 h, to obtain a self-repairing polyurethane emulsion with a solid content of 20-30%.

[0018] Further, the preparation of the modified nano-zinc oxide includes the following steps:

[0019] (1) Ethanol and deionized water are mixed, and nano-zinc oxide is added. The pH value is adjusted to 4, and ultrasonic dispersion is performed for 8-10 min. γ-Mercaptopropyltrimethoxysilane is added, and incubated at 78-82°C for 10-12 h. Centrifugation, washing, and drying are performed to obtain mercapto-modified nano-zinc oxide.

[0020] (2) Gallic acid, anhydrous ethanol, butyl acetate are mixed, triphenylphosphine, 4-methoxyphenol are added, then glycidyl methacrylate is added, and the mixture is kept at 95-105 DEG C for 5-6h, and then water washing, separation, and rotary evaporation are carried out to obtain gallic acid-glycidyl methacrylate;

[0021] (3) Gallic acid-glycidyl methacrylate and N,N-dimethylformamide are mixed, and ultrasonic stirring is carried out for 20-30min, then mercapto-nano zinc oxide is added, and the temperature is increased to 45-50 DEG C, and ultrasonic stirring is carried out for 20-30min, then a photoinitiator is added, and the mixture is irradiated with 365nm ultraviolet light for 5-7h, and then washing, rotary evaporation, and drying are carried out to obtain modified nano zinc oxide.

[0022] Further, the preparation of glycyl glycine methyl ester comprises the following steps:

[0023] Dichlorosulfoxide and methanol are mixed, and stirring is carried out in an ice bath for 50-70min, then diglycyl peptide is added, and the mixture is kept at 18-25 DEG C for 2-3h, and then kept at 63-67 DEG C for 110-130min, and then rotary evaporation is carried out to obtain glycyl glycine methyl ester hydrochloride; N,N-dimethylformamide, triethylamine, and glycyl glycine methyl ester hydrochloride are mixed, and then filtration is carried out to obtain glycyl glycine methyl ester.

[0024] Compared with the prior art, the present application has the following beneficial effects:

[0025] The present application provides a kind of high-precision wear-resistant filter material coated with nano coating and its preparation method, by component structure and process design, the filter material prepared has high-precision filtering effect, can cope with 5 μm particle size particulate matter emission, simultaneously has excellent wear resistance, antibacterial property, thermal stability, long-term use in harsh working condition environment, and its internal structure will not be damaged failure.

[0026] Non-woven fabric is used as a filter support layer, nano silicon sol dispersion liquid is coated on the surface of the filter support layer, and heat setting is carried out to form an upper filter surface layer, thereby obtaining a filter material, wherein the introduction of the nano silicon sol dispersion liquid enables the filter material to have excellent thermal stability, ultraviolet resistance and wear resistance; by controlling process parameters, the upper filter surface layer prepared has a three-dimensional structure, and after 10,000 times of powder blowing under a pressure of 5 Bar, the surface average pore size retention rate of the upper filter surface layer is above 99%; by controlling the average pore size of the upper filter surface layer to be 5-10 μm, the filtering effect and durability of the filter material are improved, and the effect of high efficiency and low resistance is realized; non-woven fabric is used as the filter support layer, and by limiting the thickness and strength of the non-woven fabric, the non-woven fabric provides stable support for the filter material.

[0027] The nano-silica sol, PTFE emulsion, acrylic emulsion, fluorocarbon surfactant, silane coupling agent, film forming agent and deionized water are mixed to obtain a nano-silica sol dispersion liquid; wherein the introduction of the nano-silica sol can improve the wear resistance and chemical stability of the material, and adjust the porosity and pore size of the coating; the introduction of the PTFE emulsion can enhance the chemical stability and temperature resistance of the coating; the addition of the acrylic emulsion can improve the original physical properties of the filter material; the introduction of the fluorocarbon surfactant is conducive to improving the dispersion effect of the PTFE emulsion and forming a three-dimensional network structure; and the addition of the silane coupling agent can improve the interface bonding between the nano-silica sol, PTFE emulsion and acrylic emulsion, and improve the integrity and uniformity of the coating; by controlling the introduction amount of each substance and the heat setting parameters, the performance of the filter material can be improved.

[0028] In order to further improve the ultraviolet resistance, antibacterial property and durability of the filter material, and make the upper filter surface layer have self-repairing property, a self-repairing polyurethane emulsion is introduced into the nano-silica sol dispersion liquid as a film forming agent; a prepolymer is synthesized by using polytetrahydrofuran and isophorone diisocyanate as raw materials; 2,2-dimethylol propionic acid is used as a hydrophilic chain extender; and modified nano-zinc oxide and glycyl glycine methyl ester are used as end-capping agents; wherein the modified nano-zinc oxide is prepared by first mercapto-functionalizing the nano-zinc oxide with γ-mercaptopropyl trimethoxysilane, and then grafting gallic acid-methyl acrylate glycidyl ester with antibacterial activity through a photo-click reaction, so as to improve the bonding strength of the ultraviolet-resistant agent, antibacterial agent nano-zinc oxide and the self-repairing polyurethane emulsion, and endow the filter material with long-term antibacterial property and ultraviolet resistance; wherein the glycyl glycine methyl ester is a dipeptide compound synthesized by using dipeptide as raw material, and the end-capping of the polyurethane can trigger the triple hydrogen bond of the end group, so that the polyurethane has good self-healing property at room temperature, thereby improving the service life of the filter material. DETAILED DESCRIPTION

[0029] The technical solutions in the present application will be described clearly and completely below by combining with the embodiments of the present application. 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 are within the protection scope of the present application.

[0030] It should be noted that if the embodiments of the present application involve directional indications such as up, down, left, right, front, back, the directional indications are only used to explain the relative position relationship between components, motion conditions, etc. in a certain posture, and if the certain posture changes, the directional indications will also change accordingly. In addition, the technical solutions of each embodiment can be combined with each other, but it must be based on the realization of ordinary skilled in the art, when the combination of technical solutions appears contradictory or unachievable, it should be considered that the combination of technical solutions does not exist, nor within the scope of protection required by the present application.

[0031] The technical solutions of the present application will be further described in detail below in combination with specific embodiments. It should be understood that the following embodiments are only used to explain the present application and not to limit the present application.

[0032] Embodiment 1: A preparation method of a high-precision wear-resistant filter material coated with a nano coating, comprising the following steps:

[0033] S1: mixing nano silicon sol, PTFE emulsion, acrylic emulsion, fluorocarbon surfactant, silane coupling agent, film forming agent and deionized water to obtain a nano silicon sol dispersion liquid;

[0034] S2: coating the nano silicon sol dispersion liquid on the surface of the filter support layer to form an upper filter surface layer by using non-woven fabric as a filter support layer and heat setting to obtain a high-precision wear-resistant filter material coated with a nano coating;

[0035] The working conditions of heat setting are as follows: the temperature of zone 1-3 is 160℃, the temperature of zone 4-6 is 180℃, the temperature of zone 6-8 is 200℃, and the vehicle speed is 5m / min;

[0036] The nano silicon sol dispersion liquid comprises, by mass fraction: 10 parts of nano silicon sol, 20 parts of PTFE emulsion, 5 parts of acrylic emulsion, 0.5 parts of fluorocarbon surfactant, 0.5 parts of silane coupling agent, 0.5 parts of film forming agent and 10 parts of deionized water;

[0037] The filter support layer is PPS non-woven fabric;

[0038] The grammage of the filter support layer is 550g / m 2 , and the thickness is 2mm; the thickness of the upper filter surface layer is 1µm; and the film forming agent is polyurethane.

[0039] Embodiment 2: A preparation method of a high-precision wear-resistant filter material coated with a nano coating, comprising the following steps:

[0040] S1: mixing nano silicon sol, PTFE emulsion, acrylic emulsion, fluorocarbon surfactant, silane coupling agent, film forming agent and deionized water to obtain a nano silicon sol dispersion liquid;

[0041] S2: coating the nanometer silica sol dispersion liquid on the surface of the filter support layer, heat setting, forming an upper layer filter surface layer, to obtain a high-precision wear-resistant filter material coated with nanometer coating;

[0042] The working conditions of heat setting are as follows: the temperature of 1-3 zones is 170 DEG C, the temperature of 4-6 zones is 190 DEG C, the temperature of 6-8 zones is 210 DEG C, and the vehicle speed is 6 m / min;

[0043] The nanometer silica sol dispersion liquid comprises, in mass fraction, 20 parts of nanometer silica sol, 30 parts of PTFE emulsion, 10 parts of acrylic emulsion, 1 part of fluorocarbon surfactant, 1 part of silane coupling agent, 1 part of film forming agent, and 37 parts of deionized water;

[0044] The filter support layer is PPS non-woven fabric;

[0045] The gram weight of the filter support layer is 550 g / m 2 , and the thickness is 2 mm; the thickness of the upper layer filter surface layer is 1 µm;

[0046] The film forming agent is polyurethane.

[0047] Embodiment 3: a preparation method of a high-precision wear-resistant filter material coated with nanometer coating, comprising the following steps:

[0048] S1: mixing nanometer silica sol, PTFE emulsion, acrylic emulsion, fluorocarbon surfactant, silane coupling agent, film forming agent, and deionized water to obtain nanometer silica sol dispersion liquid;

[0049] S2: coating the nanometer silica sol dispersion liquid on the surface of the filter support layer, heat setting, forming an upper layer filter surface layer, to obtain a high-precision wear-resistant filter material coated with nanometer coating;

[0050] The working conditions of heat setting are as follows: the temperature of 1-3 zones is 180 DEG C, the temperature of 4-6 zones is 200 DEG C, the temperature of 6-8 zones is 220 DEG C, and the vehicle speed is 7 m / min;

[0051] The nanometer silica sol dispersion liquid comprises, in mass fraction, 30 parts of nanometer silica sol, 40 parts of PTFE emulsion, 20 parts of acrylic emulsion, 2 parts of fluorocarbon surfactant, 2 parts of silane coupling agent, 2 parts of film forming agent, and 60 parts of deionized water;

[0052] The filter support layer is PPS non-woven fabric;

[0053] The gram weight of the filter support layer is 550 g / m 2 , and the thickness is 2 mm; the thickness of the upper layer filter surface layer is 1 µm;

[0054] The film-forming agent is polyurethane.

[0055] Embodiment 4: A method for preparing a high-precision wear-resistant filter material coated with a nano coating, comprising the following steps:

[0056] S1: mixing a nano-silica sol, a PTFE emulsion, an acrylic emulsion, a fluorocarbon surfactant, a silane coupling agent, a film-forming agent, and deionized water to obtain a nano-silica sol dispersion;

[0057] S2: coating the nano-silica sol dispersion on the surface of a filter support layer made of non-woven fabric, and heat setting to form an upper filter surface layer, thereby obtaining a high-precision wear-resistant filter material coated with a nano coating;

[0058] The working conditions for heat setting are as follows: the temperature in Zone 1-3 is 170°C, the temperature in Zone 4-6 is 190°C, the temperature in Zone 6-8 is 210°C, and the vehicle speed is 6 m / min;

[0059] The nano-silica sol dispersion comprises, by mass fraction: 20 parts of nano-silica sol, 30 parts of PTFE emulsion, 10 parts of acrylic emulsion, 1 part of fluorocarbon surfactant, 1 part of silane coupling agent, 1 part of film-forming agent, and 37 parts of deionized water;

[0060] The filter support layer is PPS non-woven fabric;

[0061] The grammage of the filter support layer is 550 g / m 2 , and the thickness is 2 mm; the thickness of the upper filter surface layer is 1 µm;

[0062] The film-forming agent is a self-repairing polyurethane emulsion, which is prepared by the following steps:

[0063] Under a nitrogen atmosphere, 5.2 g of polytetrahydrofuran, 3.5 g of isophorone diisocyanate, and 1 drop of dibutyltin dilaurate are mixed, and incubated at 78°C for 60 min. Then, 0.7 g of a mixture of 2,2-dimethylol propionic acid and 3 mL of N,N-dimethylformamide is added, and incubation is continued for 80 min. Then, 0.8 g of modified nano-zinc oxide and 6 mL of N,N-dimethylformamide are added, and the temperature is lowered to 35°C. Then, 0.2 g of triethylamine is added, and incubation is continued for 40 min. Then, 1.4 g of a mixture of glycylglycine methyl ester and 6 mL of N,N-dimethylformamide is added, and incubation is continued in an ice water bath for 2 h. Finally, deionized water is added for emulsification for 1 h, thereby obtaining a self-repairing polyurethane emulsion with a solid content of 20%;

[0064] The preparation of modified nano-zinc oxide comprises the following steps:

[0065] (1) 60 g ethanol, 20 g deionized water were mixed, 0.5 g nano zinc oxide was added, the pH value was adjusted to 4, and ultrasonic dispersion was performed for 8 min, 2 mL γ-mercaptopropyl trimethoxysilane was added, and the mixture was incubated at 78°C for 12 h, then centrifuged, washed, and dried to obtain mercapto-nano zinc oxide;

[0066] (2) 1.7 g gallic acid, 20 mL anhydrous ethanol, and 40 mL butyl acetate were mixed, 9 mg triphenylphosphine and 10 mg 4-methoxyphenol were added, and then 2.8 g glycidyl methacrylate was added, and the mixture was incubated at 95°C for 6 h, then water was added for separation, and rotary evaporation was performed to obtain gallic acid-glycidyl methacrylate;

[0067] (3) 2.5 g gallic acid-glycidyl methacrylate and 30 mL N,N-dimethylformamide were mixed and ultrasonically stirred for 20 min, 1.8 g mercapto-nano zinc oxide was added, the temperature was raised to 45°C, ultrasonic stirring was performed for 20 min, 0.1 g photoinitiator was added, and the mixture was irradiated with 365 nm ultraviolet light for 5 h, then washed, rotary evaporated, and dried to obtain modified nano zinc oxide;

[0068] The preparation of the glycyl glycine methyl ester comprises the following steps:

[0069] 6.2 mL dichlorosulfoxide and 75 mL methanol were mixed and stirred in an ice bath for 50 min, 6.6 g bisglycopeptide was added, and the mixture was incubated at 18°C for 3 h and at 63°C for 130 min, then rotary evaporation was performed to obtain glycyl glycine methyl ester hydrochloride; 25 mL N,N-dimethylformamide, 1 mmol triethylamine, and 1 mmol glycyl glycine methyl ester hydrochloride were mixed, and filtration was performed to obtain glycyl glycine methyl ester.

[0070] Example 5: A method for preparing a high-precision wear-resistant filter material coated with a nano coating, comprising the following steps:

[0071] S1: Nano silicon sol, PTFE emulsion, acrylic emulsion, fluorocarbon surfactant, silane coupling agent, film-forming agent, and deionized water were mixed to obtain a nano silicon sol dispersion liquid;

[0072] S2: The nano silicon sol dispersion liquid was coated on the surface of a filter support layer made of non-woven fabric, and heat setting was performed to form an upper filter surface layer, thereby obtaining a high-precision wear-resistant filter material coated with a nano coating;

[0073] The working conditions for heat setting were as follows: the temperature of zones 1-3 was 170°C, the temperature of zones 4-6 was 190°C, the temperature of zones 6-8 was 210°C, and the vehicle speed was 6 m / min;

[0074] The nano-silica sol dispersion liquid is composed of 20 parts of nano-silica sol, 30 parts of PTFE emulsion, 10 parts of acrylic emulsion, 1 part of fluorocarbon surfactant, 1 part of silane coupling agent, 1 part of film forming agent, and 37 parts of deionized water, in terms of mass fraction;

[0075] The filter support layer is PPS non-woven fabric;

[0076] The gram weight of the filter support layer is 550 g / m 2 , and the thickness is 2 mm; the thickness of the upper filter surface layer is 1 µm;

[0077] The film forming agent is a self-repairing polyurethane emulsion, and the preparation includes the following steps:

[0078] Under a nitrogen atmosphere, 5.2 g of polytetrahydrofuran, 3.5 g of isophorone diisocyanate, and 1 drop of dibutyltin dilaurate are mixed, and incubated at 80°C for 50 min. Then, 0.7 g of a mixture of 2,2-dimethylol propionic acid and 3 mL of N,N-dimethylformamide is added, and incubation is continued for 90 min. Then, 0.8 g of modified nano-zinc oxide and 6 mL of N,N-dimethylformamide are added, and the temperature is lowered to 38°C. Then, 0.2 g of triethylamine is added, and incubation is continued for 50 min. Then, 1.4 g of a mixture of glycylglycine methyl ester and 6 mL of N,N-dimethylformamide is added, and incubation is continued in an ice water bath for 2.5 h. Then, deionized water is added for emulsification for 1.5 h, to obtain a self-repairing polyurethane emulsion with a solid content of 25%;

[0079] The preparation of the modified nano-zinc oxide includes the following steps:

[0080] (1) 60 g of ethanol and 20 g of deionized water are mixed, 0.5 g of nano-zinc oxide is added, the pH value is adjusted to 4, and ultrasonic dispersion is performed for 9 min. Then, 2 mL of γ-mercaptopropyltrimethoxysilane is added, and incubation is performed at 80°C for 11 h. Then, centrifugation, washing, and drying are performed, to obtain mercapto-modified nano-zinc oxide;

[0081] (2) 1.7 g of gallic acid, 20 mL of anhydrous ethanol, and 40 mL of butyl acetate are mixed, 9 mg of triphenylphosphine and 10 mg of 4-methoxyphenol are added, and then 2.8 g of glycidyl methacrylate is added. Incubation is performed at 100°C for 5.5 h, water washing and liquid-liquid separation are performed, and rotary evaporation is performed, to obtain gallic acid-glycidyl methacrylate;

[0082] (3) 2.5 g of gallic acid-glycidyl methacrylate and 30 mL of N,N-dimethylformamide are mixed, and ultrasonic stirring is performed for 25 min. Then, 1.8 g of mercapto-modified nano-zinc oxide is added, the temperature is raised to 48°C, ultrasonic stirring is performed for 25 min, 0.1 g of a photoinitiator is added, and irradiation is performed with 365 nm ultraviolet light for 6 h. Then, washing, rotary evaporation, and drying are performed, to obtain modified nano-zinc oxide;

[0083] The preparation of the glycyl glycine methyl ester comprises the following steps:

[0084] 6.2 mL of thionyl chloride, 75 mL of methanol were mixed, stirred in an ice bath for 60 min, 6.6 g of diglycine was added, incubated at 20°C for 2.5 h, incubated at 65°C for 120 min, rotary evaporation, to obtain glycyl glycine methyl ester hydrochloride; 25 mL of N,N-dimethylformamide, 1 mmol of triethylamine, 1 mmol of glycyl glycine methyl ester hydrochloride were mixed, filtered, to obtain glycyl glycine methyl ester.

[0085] Example 6: A preparation method of a high-precision wear-resistant filter material coated with a nano coating, comprising the following steps:

[0086] S1: mixing a nano silicon sol, a PTFE emulsion, an acrylic emulsion, a fluorocarbon surfactant, a silane coupling agent, a film forming agent, and deionized water to obtain a nano silicon sol dispersion liquid;

[0087] S2: coating the nano silicon sol dispersion liquid on the surface of a filter support layer taking a non-woven fabric as the filter support layer, heat setting to form an upper filter surface layer, to obtain a high-precision wear-resistant filter material coated with a nano coating;

[0088] The working conditions of heat setting are as follows: the temperature of zones 1-3 is 170°C, the temperature of zones 4-6 is 190°C, the temperature of zones 6-8 is 210°C, and the vehicle speed is 6 m / min;

[0089] The nano silicon sol dispersion liquid comprises, in mass fraction: 20 parts of nano silicon sol, 30 parts of PTFE emulsion, 10 parts of acrylic emulsion, 1 part of fluorocarbon surfactant, 1 part of silane coupling agent, 1 part of film forming agent, and 37 parts of deionized water;

[0090] The filter support layer is a PPS non-woven fabric;

[0091] The grammage of the filter support layer is 550 g / m 2 , and the thickness is 2 mm; the thickness of the upper filter surface layer is 1 µm;

[0092] The film forming agent is a self-repairing polyurethane emulsion, and the preparation comprises the following steps:

[0093] Under nitrogen atmosphere, 5.2 g of polytetrahydrofuran, 3.5 g of isophorone diisocyanate, 1 drop of dibutyltin dilaurate were mixed, and incubated at 82°C for 40 min. A mixture of 0.7 g of 2,2-dimethylol propionic acid and 3 mL of N,N-dimethylformamide was added, and incubated for another 100 min. A mixture of 0.8 g of modified nano zinc oxide and 6 mL of N,N-dimethylformamide was added, and the temperature was lowered to 40°C. 0.2 g of triethylamine was added, and incubated for 60 min. A mixture of 1.4 g of glycylglycine methyl ester and 6 mL of N,N-dimethylformamide was added, and incubated for 3 h in an ice water bath. The mixture was emulsified with deionized water for 2 h to obtain a self-repairing polyurethane emulsion with a solid content of 30%.

[0094] The preparation of the modified nano zinc oxide comprises the following steps:

[0095] (1) 60 g of ethanol and 20 g of deionized water were mixed, 0.5 g of nano zinc oxide was added, the pH value was adjusted to 4, and ultrasonic dispersion was performed for 10 min. 2 mL of γ-mercaptopropyltrimethoxysilane was added, and incubated at 82°C for 10 h. Centrifugation, washing and drying were performed to obtain mercapto nano zinc oxide.

[0096] (2) 1.7 g of gallic acid, 20 mL of anhydrous ethanol and 40 mL of butyl acetate were mixed, 9 mg of triphenylphosphine and 10 mg of 4-methoxyphenol were added, and then 2.8 g of glycidyl methacrylate was added. Incubate at 105°C for 5 h, water wash, rotary evaporation to obtain gallic acid-glycidyl methacrylate.

[0097] (3) 2.5 g of gallic acid-glycidyl methacrylate and 30 mL of N,N-dimethylformamide were mixed and ultrasonically stirred for 30 min. 1.8 g of mercapto nano zinc oxide was added, and the temperature was raised to 50°C. Ultrasonic stirring was performed for 30 min. 0.1 g of photoinitiator was added, and irradiated with 365 nm ultraviolet light for 7 h. Washing, rotary evaporation and drying were performed to obtain modified nano zinc oxide.

[0098] The preparation of the glycylglycine methyl ester comprises the following steps:

[0099] 6.2 mL of dichlorosulfoxide and 75 mL of methanol were mixed and stirred in an ice bath for 70 min. 6.6 g of bisglycine was added, and incubated at 25°C for 2 h. Incubate at 67°C for 110 min, rotary evaporation to obtain glycylglycine methyl ester hydrochloride; 25 mL of N,N-dimethylformamide, 1 mmol of triethylamine and 1 mmol of glycylglycine methyl ester hydrochloride were mixed and filtered to obtain glycylglycine methyl ester.

[0100] Comparative Example 1: The thickness of the upper filter layer was 0.4 µm, and the other procedures were normal.

[0101] Comparative Example 2: In comparison with Example 2, the particle size of the nanosilica sol is 20 nm (Z3020, Linyi Zhixuan New Material Co., Ltd.), and other procedures are normal.

[0102] Comparative Example 3: In comparison with Example 2, the composition of the nanosilica sol dispersion is: nanosilica 10 parts, PTFE emulsion 40 parts, acrylic emulsion 5 parts, deionized water 45 parts, in terms of mass parts, and other procedures are normal.

[0103] Comparative Example 4: In comparison with Example 6, no modified nanometer zinc oxide is prepared, and other procedures are normal.

[0104] Comparative Example 5: In comparison with Example 6, no glycyl glycine methyl ester is prepared, and other procedures are normal.

[0105] The sources of the raw materials used (only as an example):

[0106] Nanosilica sol JN-30 (8-15 nm): Jinan Haiwei Chemical Co., Ltd.; PTFE emulsion ST801AW NC010: DuPont, USA; Acrylic emulsion (60%), photoinitiator (benzophenone 119-61-9): Suzhou Sun Chemical Co., Ltd.; Polyurethane 001: Langfang Wante Anticorrosion Material Co., Ltd.; Fluorocarbon surfactant (FC-4430): Huizhou Dongxinda Chemical Co., Ltd.; Silane coupling agent (γ-mercaptopropyl trimethoxysilane) M100619, polytetrahydrofuran P118599, isophorone diisocyanate I109582, dibutyltin dilaurate D100274, 2,2-dimethylol propionic acid B104539, triethylamine T103285, nanometer zinc oxide Z112847, gallic acid G131992, triphenylphosphine T104478, 4-methoxyphenol M170858, glycidyl methacrylate G106686, dipeptide G119491: Aladdin Reagent; Ethanol, butyl acetate, thionyl chloride, methanol, N,N-dimethylformamide, analytical pure: commercially available.

[0107] Performance test: The materials prepared in the examples and comparative examples are tested:

[0108] Filtering performance: determined according to VDI3926, with a size diameter of 150 mm, a filtering air speed of 2 m / min, and an inlet dust concentration of 5 g / m 3, the experimental sequence is initial 30 times, stabilization 5000 times, and last 30 times; the initial 30 times and the last 30 times: when the pressure difference of two surfaces of the filter material reaches 1000 Pa, the dust on the surface of the filter material is cleaned by pulse air, and then the next process is carried out, and the process is repeated for 30 times; the stabilization 5000 times: the cleaning pressure is 5 bar, the cleaning is carried out once every 5 s, and the number of times is 5000 times; the calculation formula of the outlet dust concentration is: C = M / (1.85 * t / 3600), and the unit is mg / m 3 , the cycle time s is the total time spent in the last 30 times;

[0109] Wear resistance: determined according to GB / T21196.2-2007, using a Martindale wear tester, the pressure is 12 kPa, the sample diameter is 38 mm, NO.600 water sandpaper is used as abrasive, the abrasive diameter is 140 mm, then whether the coating is damaged or not is observed, 5200-5300 times without damage is qualified (including 5200), less than 5200 times is unqualified, 5300-5500 times is excellent (including 5300), and more than or equal to 5500 times is excellent: the results are shown in Table 1;

[0110] Table 1

[0111]

[0112] Antibacterial durability: examples 4-6, comparative examples 4-5 are tested: after irradiation for 72 h by a UV lamp with a wavelength of 254 nm, the antibacterial rate is tested according to GB / T21866-2008, staphylococcus aureus is used as the test strain, and the antibacterial rate is tested by the plate method; the results are shown in Table 2;

[0113] Table 2

[0114]

[0115] The application provides a high-precision wear-resistant filter material coated with a nano coating and a preparation method thereof, through component structure and process design, the prepared filter material has high-precision filtering effect, can cope with 5 mu m particle size particulate matter emission, and simultaneously has excellent wear resistance, antibacterial property and thermal stability, and the internal structure will not be damaged and failed during long-term use in a harsh working environment.

[0116] Comparing example 2 with comparative example 1, it can be seen that the thickness of the upper filter surface layer is in the preferred range, the obtained filter material has high collection efficiency, low outlet concentration, long cycle time and good wear resistance; comparing example 2 with comparative example 2, it can be seen that the particle size of the nano-silica sol is in the preferred range, the obtained filter material has high collection efficiency, low outlet concentration, long cycle time and good wear resistance; comparing example 2 with comparative example 3, it can be seen that the latter fails to form a three-dimensional network structure, and the obtained filter material has low collection efficiency, high outlet concentration and low cycle time.

[0117] Comparing example 6 with comparative example 4 and comparative example 5, it can be seen that in order to further improve the ultraviolet resistance, antibacterial property and durability of the filter material, and to make the upper filter surface layer have self-repairing property, a self-repairing polyurethane emulsion is introduced into the nano-silica sol dispersion as a film-forming agent, a prepolymer is synthesized with polytetrahydrofuran and isophorone diisocyanate as raw materials, 2,2-dimethylol propionic acid is used as a hydrophilic chain extender, and modified nano-zinc oxide and glycyl glycine methyl ester are used as end-capping agents, wherein the modified nano-zinc oxide is prepared by first mercapto-functionalizing the nano-zinc oxide with γ-mercaptopropyl trimethoxysilane, and then grafting gallic acid-methyl acrylate glycidyl ester with antibacterial activity through a photo-click reaction, so as to improve the bonding strength of the ultraviolet-resistant agent, the antibacterial agent nano-zinc oxide and the self-repairing polyurethane emulsion, and to endow the filter material with long-term antibacterial property and ultraviolet resistance; wherein the glycyl glycine methyl ester is a dipeptide compound synthesized with diglycyl peptide as raw material, and end-capping the polyurethane can trigger the triple hydrogen bond of the end group, so that it has good self-healing property at room temperature, thereby improving the service life of the filter material.

[0118] The above only describes the embodiments of the present application, and does not limit the patent scope of the present application, and any equivalent structural transformation made according to the present application, or direct / indirect application in other related technical fields within the inventive concept of the present application is included in the patent protection scope of the present application.

Claims

1. A method for producing a high-precision wear-resistant filter material coated with a nano-coating, characterized in that, Comprise the following steps: S1: mix nano-silica sol, PTFE emulsion, acrylic emulsion, fluorocarbon surfactant, silane coupling agent, film forming agent, deionized water to obtain nano-silica sol dispersion liquid; S2: take non-woven fabric as filter support layer, coat nano-silica sol dispersion liquid on the surface of the filter support layer, heat setting, form upper filter surface layer, obtain a high-precision wear-resistant filter material coated with nano coating; The film forming agent is a self-repairing polyurethane emulsion, and the preparation comprises the following steps: Under nitrogen atmosphere, mix polytetrahydrofuran, isophorone diisocyanate, dibutyltin dilaurate, keep at 78-82℃ for 40-60min, add 2,2-dimethylol propionic acid, N,N-dimethylformamide mixture, continue to keep at 80-100min, add modified nano zinc oxide, N,N-dimethylformamide mixture, cool to 35-40℃, add triethylamine, keep at 40-60min, add glycyl glycine methyl ester, N,N-dimethylformamide mixture, keep at 2-3h in ice water bath, emulsify with deionized water for 1-2h, obtain self-repairing polyurethane emulsion; The preparation of modified nano zinc oxide comprises the following steps: (1) mix ethanol, deionized water, add nano zinc oxide, adjust pH value to 4, ultrasonic dispersion for 8-10min, add γ-mercaptopropyl trimethoxysilane, keep at 78-82℃ for 10-12h, centrifugal, washing, drying, obtain mercapto nano zinc oxide; (2) mix gallic acid, anhydrous ethanol, butyl acetate, add triphenylphosphine, 4-methoxyphenol, then add glycidyl methacrylate, keep at 95-105℃ for 5-6h, water washing, liquid-liquid separation, rotary evaporation, obtain gallic acid-glycidyl methacrylate; (3) mix gallic acid-glycidyl methacrylate, N,N-dimethylformamide, ultrasonic stirring for 20-30min, add mercapto nano zinc oxide, heat to 45-50℃, ultrasonic stirring for 20-30min, add photoinitiator, irradiate with 365nm ultraviolet light for 5-7h, washing, rotary evaporation, drying, obtain modified nano zinc oxide.

2. The method for preparing a high-precision wear-resistant filter material coated with a nano-coating according to claim 1, characterized in that, The working conditions of heat setting: temperature of 1-3 area is 160-180℃, temperature of 4-6 area is 180-200℃, temperature of 6-8 area is 200-220℃, vehicle speed is 5-7m / min.

3. The method for preparing a high-precision wear-resistant filter material coated with a nano-coating according to claim 1, characterized in that, The composition of the nano-silica sol dispersion liquid is: nano-silica sol 10-30 parts, PTFE emulsion 20-40 parts, acrylic emulsion 5-20 parts, fluorocarbon surfactant 0.5-2 parts, silane coupling agent 0.5-2 parts, film forming agent 0.5-2 parts, deionized water 10-60 parts, by mass fraction.

4. The method of claim 1, wherein the high-precision wear-resistant filter material coated with a nano-coating is prepared by the following steps: 1) preparing a precursor solution; 2) coating the precursor solution on a substrate to form a precursor film; 3) annealing the precursor film to form a nano-coating; and 4) removing the substrate. The filter support layer is one or several composite non-woven fabrics selected from PPS non-woven fabric, aramid non-woven fabric, polyester non-woven fabric, PTFE non-woven fabric and glass fiber non-woven fabric.

5. The method for preparing a high-precision wear-resistant filter material coated with a nano-coating according to claim 1, characterized in that, The filter support layer has a grammage of 400-800 g / m 2 The upper filter surface layer has a pore size distribution of 5-10 pm, and a thickness of 0.5-2 pm.

6. The method for preparing a high-precision wear-resistant filter material coated with a nano-coating according to claim 1, characterized in that, The preparation of glycyl glycine methyl ester comprises the following steps: Mixing dichlorosulfoxide and methanol, stirring in ice bath for 50-70 min, adding diglycyl peptide, incubating at 18-25℃ for 2-3 h, incubating at 63-67℃ for 110-130 min, rotary evaporation to obtain glycylglycine methyl ester hydrochloride; mixing N,N-dimethylformamide, triethylamine and glycylglycine methyl ester hydrochloride, filtering to obtain glycylglycine methyl ester.

7. A high-precision wear-resistant filter material coated with a nanocoating, characterized in that The filter material prepared by the preparation method in any one of claims 1-6 is applied to the fields of air filtration and industrial waste gas treatment.

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