CN105986480B - Protective coating, filtrate, matrix and its protective coating preparation method - Google Patents

Abstract

The present invention relates to a method for preparing a protective coating, which comprises the following steps: configuring a mixed solution a to contain a polyelectrolyte of 1-50 g/L and a strong electrolyte of 0.01-2 mol/L; a is formed on the surface of the substrate and the internal microstructure of the substrate, and the substrate is dried; take 50-100 parts of 2%-15% polytetrafluoroethylene nanoparticle dispersion, 0-50 parts by mass 1% to 10% of the polystyrene nanoparticle dispersion liquid is mixed, and stirred or ultrasonically dispersed to obtain a mixed liquid b; the mixed liquid b is formed on the surface of the substrate and the internal microstructure of the substrate, and the mixed liquid b is formed. The substrate is dried; the temperature is raised to 160-220° C. and baked to melt the polystyrene particles, solidify the polytetrafluoroethylene particles, and take them out to cool down naturally. In addition, the present invention also relates to a protective coating, a filter material and a substrate.

Description

Protective coating, filter material, substrate and preparation method of protective coating

technical field

The invention relates to a protective coating, a filter material, a substrate and a preparation method of the protective coating.

Background technique

The haze problem has become one of the most serious environmental pollution problems in my country, especially in the Beijing-Tianjin-Hebei region. According to statistics, more than 20% of PM2.5 that causes smog comes from industrial flue gas emissions, such as thermal power plants, cement plants, waste incineration plants, etc. Therefore, upgrading and transforming the flue gas purification equipment of flue gas emitting enterprises is the key to smog control. core tasks. At present, industrial flue gas purification equipment is divided into two categories according to technology: one is electrostatic dust removal technology, and the other is filter bag dust removal technology. The industrial flue gas after electrostatic precipitator is used, and the emission concentration of particulate matter is generally 50-100mg/m , as low as 15-30 mg/m , while the filter bag dust removal technology is used, the emission concentration of particulate matter is generally less than 50 mg/m , as low as 0-5 mg/m . According to the new national emission standard GB13223-2011, the emission concentration of particulate matter is less than 20mg/m Therefore, it is necessary to use electric bag combination or filter bag dust removal technology to meet the requirements stably.

The core of filter bag dust removal technology is filter material. As a consumable material, the filter material has a certain lifespan. Taking the polyphenylene sulfide high-temperature dust removal filter material commonly used in coal-fired power plants as an example, the service life of the domestic filter material is about 1-3 years, and the imported filter bag can reach more than 3 years. Extending the service life of the filter bag can not only greatly reduce the cost of filter bag dust removal, but also prolong the time for the company to stop production for maintenance, which is of great significance for related enterprises to carry out environmental protection transformation. In order to improve the service life of the filter material, many well-known companies at home and abroad, such as Fusheng Group, Dongfang Filter Bags, Borg, Andrews, BWF, etc., all use the PTFE impregnation technology to process the filter material, so as to improve the filter quality. The anti-oxidation ability, acid-base corrosion resistance, filtration efficiency and dust-cleaning ability of the bag can prolong its service life. However, the existing PTFE impregnation technology has two important shortcomings. One is that the coverage rate of PTFE is low, which cannot completely protect the filter material fibers; Vinyl falls off easily. Therefore, the effect of this technology on the life of the filter material is limited at present.

SUMMARY OF THE INVENTION

In view of this, it is indeed necessary to provide a protective coating, a filter material, a substrate and a preparation method of the protective coating with high polytetrafluoroethylene coverage and strong adsorption force with the filter material fiber.

A protective coating comprising a polyelectrolyte layer and a polytetrafluoroethylene nanoparticle layer, wherein the polyelectrolyte layer and the polytetrafluoroethylene nanoparticle layer are laminated.

A filter material comprising a filter material base and a protective coating provided on the filter base, the protective coating comprising a polyelectrolyte layer and a polytetrafluoroethylene nanoparticle layer, the polyelectrolyte layer and the The polytetrafluoroethylene nanoparticle layers are arranged in layers.

A substrate comprising a substrate body and a protective coating provided on the substrate body, the protective coating comprising a polyelectrolyte layer and a polytetrafluoroethylene nanoparticle layer, the polyelectrolyte layer and the polytetrafluoroethylene Layers of ethylene nanoparticles are arranged one on top of the other.

A preparation method of protective coating, it comprises the following steps: configure mixed solution a, make it contain the polyelectrolyte of 1～50 g/L, the strong electrolyte of 0.01～2 mol/L; The mixed solution a is formed in The surface of the substrate and the internal microstructure of the substrate are dried, and the substrate is dried; 50-100 parts of the polytetrafluoroethylene nanoparticle dispersion with a mass fraction of 2% to 15%, 0-50 parts of a mass fraction of 1% ~10% polystyrene nanoparticle dispersion liquid is mixed, and stirred or ultrasonically dispersed to obtain mixed liquid b; the mixed liquid b is formed on the surface of the substrate and the microstructure inside the substrate, and the substrate is dried ; Heat the temperature to 160~220°C and bake to melt the polystyrene particles, solidify the polytetrafluoroethylene particles, and take them out to cool down naturally.

A preparation method of filter material protective coating, it comprises the following steps: configure mixed solution a, make it comprise the polyelectrolyte of 1～50g/L, the strong electrolyte of 0.01～2 mol/L; Described mixed solution a is formed On the surface of a filter material and the fiber surface inside the filter material, and drying the filter material; take 50-100 parts of a polytetrafluoroethylene nanoparticle dispersion with a mass fraction of 2%-15%, 0-50 parts The polystyrene nanoparticle dispersion liquid with a mass fraction of 1% to 10% is mixed, and stirred or ultrasonically dispersed to obtain a mixed liquid b; the mixed liquid b is formed on the surface of the filter material and the fiber surface inside the filter material , and drying the filter material; heating to 160-220° C. for baking to melt the polystyrene particles, solidify the polytetrafluoroethylene particles, and take them out to cool down naturally.

Compared with the prior art, the protective coating provided by the present invention has the following advantages: firstly, the coverage of polytetrafluoroethylene in the prepared protective coating is high, which can improve the oxidation resistance, acid and alkali resistance of the protective coating Corrosion ability and strength; secondly, the prepared protective coating has strong bonding force with the substrate; thirdly, the protective coating has low surface energy and super-hydrophobicity.

The preparation method of the protective coating provided by the present invention has the following advantages. First, the polyelectrolyte is used to improve the adsorption between the matrix and the polytetrafluoroethylene nanoparticles, thereby improving the coverage rate of the polytetrafluoroethylene nanoparticles on the surface of the substrate; secondly, The polystyrene nanoparticles are added and melted to form a porous nanostructure, and the polystyrene particles are well fixed on the surface of the substrate.

Description of drawings

Fig. 1 is a flow chart of a method for preparing a filter material fiber protective coating provided by an embodiment of the present invention.

FIG. 2 is a schematic structural diagram of a protective coating provided by an embodiment of the present invention.

FIG. 3 is a schematic structural diagram of a protective coating provided by another embodiment of the present invention.

Description of main component symbols

polyelectrolyte layer 10, 20 PTFE Nanoparticle Layer 11, 22 polystyrene layer twenty one matrix 30 protective coating 100, 200

The following specific embodiments will further illustrate the present invention in conjunction with the above drawings.

Detailed ways

The technical solutions of the present invention are further described in detail below with reference to specific embodiments.

Please refer to Fig. 1, the embodiment of the present invention provides a kind of preparation method of protective coating, it comprises the following steps:

Step 1: Configure the mixed solution a so that it contains 1~50 g/L of polyelectrolyte and 0.01~2 mol/L of strong electrolyte;

Step 2: forming the mixed solution a on the surface of a substrate and the microstructure inside the substrate, and drying the substrate;

Step 3: Mix 50~100 parts of polytetrafluoroethylene nanoparticle dispersion liquid with a mass fraction of 2%~15% and 0~50 parts of polystyrene nanoparticle dispersion liquid with a mass fraction of 1%~10%, and Perform stirring or ultrasonic dispersion to obtain mixed solution b;

Step 4: forming the mixed solution b on the surface of the substrate and the internal microstructure of the substrate, and drying the substrate;

Step 5: heating to 160-220° C. and baking to melt the polystyrene particles, solidify the polytetrafluoroethylene particles, and take them out to cool down naturally.

In step (1), the polyelectrolyte is a polymer that can be ionized in a polar solution to charge the polymer chain, mainly including: polyacrylic acid, polymethacrylic acid, polystyrenesulfonic acid, polyvinylsulfonic acid , polyvinylphosphoric acid, polyallylamine hydrochloride, polyethyleneimine, polyvinylamine, polydiallyldimethylammonium chloride, polyvinylpyridine, polyphosphate, polysilicate, etc. One of the polyelectrolytes can be selected, or a plurality of them can be selected and used in combination. The strong electrolyte, that is, most salt electrolytes except strong acid and strong base that can completely ionize ions in aqueous solution, mainly includes sodium chloride, potassium chloride, manganese chloride, ammonium sulfate, sodium sulfate, potassium sulfate Wait. One of the strong electrolytes can be selected, or a plurality of them can be used in combination.

In step (2), the substrate may be immersed in the mixed solution a for a period of time to deposit, or the mixed solution may be sprayed or smeared on the surface of the substrate, so that the substrate surface is formed with the Mixture b. Preferably, the substrate is immersed in the mixed solution for 5-20 minutes, so that the polyelectrolyte and the strong electrolyte in the mixed solution are adsorbed into the internal microstructure of the substrate.

The drying temperature and time are not limited. Preferably, the drying temperature is 60°C to 80°C, and the drying time is 20 minutes to 40 minutes. The purpose of the drying is to volatilize the solvent.

The matrix can be various fibers and other porous materials, including: filter cloth, filter membrane, filter bag or filter sponge. More specifically, the filter cloth includes cotton, linen, polypropylene, polyester, nylon and other filter cloths with an average pore diameter of less than 200 microns; fiber, polypropylene, polyester and other materials; the filter membrane includes nylon, polytetrafluoroethylene, mixed fiber ester, polyvinylidene fluoride, microporous filter membrane of glass fiber material, etc.; the filter sponge includes fiber Sponge, polyvinyl alcohol, polyurethane foam sponge, etc.

In step (3), the polytetrafluoroethylene nanoparticle dispersion can be obtained by dispersing the polytetrafluoroethylene nanoparticles in a solvent, or by a polymerization method such as suspension polymerization and emulsion polymerization. The particle size of the polytetrafluoroethylene nanoparticle can be 50-1000 nm, and it can exist in a phase state such as spherical particle, ellipsoidal particle, irregular-shaped particle, powder, emulsion, concentrated dispersion liquid, and the like.

The polystyrene nanoparticle dispersion liquid can be obtained by dispersing the polystyrene nanoparticles in a solvent, or by a polymerization method such as suspension polymerization and emulsion polymerization. The particle size of the polystyrene nanoparticles may be 50-1000 nm.

The time and form of the stirring or ultrasonic dispersion are not limited, as long as the polytetrafluoroethylene nanoparticles and the polystyrene nanoparticles can be uniformly dispersed. Preferably, the ultrasonic dispersion time is 20-30 minutes.

In step (4), the filter material is immersed in the mixed solution b for deposition for a period of time, or the mixed solution is sprayed or smeared on the surface of the substrate, so that the surface of the substrate is formed with the Mixture b. Preferably, the mixed solution is sprayed onto the surface of the substrate to completely wet the substrate, so that the polytetrafluoroethylene nanoparticles and polystyrene nanoparticles in the mixed solution b are adsorbed to the inner microparticles of the substrate. in the structure.

The drying temperature and time are not limited. Preferably, the drying temperature is 60°C to 80°C, and the drying time is 20 minutes to 40 minutes. The purpose of the drying is to volatilize the solvent.

In step (5), the purpose of the baking is to melt the polystyrene nanoparticles, and play the role of bonding the polytetrafluoroethylene nanoparticles to the surface of the substrate, and at the same time play the role of The effect of curing polytetrafluoroethylene nanoparticles. The baking time is not limited, as long as the polystyrene nanoparticles can be melted and the polytetrafluoroethylene nanoparticles can be solidified. Preferably, the baking time is more than 10 minutes. During the baking process, the surface of the PTFE nanoparticles will be slightly melted, but the prototype can still be maintained.

Of course, the matrix can also be removed in this method.

The preparation method of the protective coating provided by the present invention has the following advantages. First, the use of polyelectrolyte can improve the adsorption between the matrix and the PTFE nanoparticles, thereby improving the coverage rate of the PTFE nanoparticles on the surface of the matrix; , adding polystyrene nanoparticles and melting them to form a porous nanostructure, which can make the polystyrene particles well fixed on the surface of the substrate.

The present invention also relates to a protective coating obtained by the above preparation method. When the mixed solution b does not contain the polystyrene nanoparticle dispersion liquid, the protective coating 100 is obtained. Referring to FIG. 2 , the protective coating 100 includes a polyelectrolyte layer 10 and a polytetrafluoroethylene nanoparticle layer 11 , and the polyelectrolyte layer 10 and the polytetrafluoroethylene nanoparticle layer 11 are stacked. The arrangement tightness of the polytetrafluoroethylene nanoparticle layer 11 is higher, and the anti-oxidation, acid and alkali resistance of the protective coating are stronger.

The present invention also relates to another protective coating obtained by the above preparation method. When the mixed solution b contains the polystyrene nanoparticle dispersion liquid, the protective coating 200 is obtained. The protective coating 200 is a structure with nanometer topography. The structure of the nanotopography is related to the particle size of the polytetrafluoroethylene and polystyrene nanoparticles. Please refer to FIG. 3 , the protective coating 200 includes a polyelectrolyte layer 20 , a polystyrene layer 21 and a polytetrafluoroethylene nanoparticle layer 22 , and the polyelectrolyte layer 20 is laminated with the polystyrene layer 21 set up. The thickness of the polyelectrolyte layer 20 is less than 100 nm. The polystyrene layer 21 and the polytetrafluoroethylene particle layer 22 are stacked and disposed, and the polytetrafluoroethylene nanoparticles in the polytetrafluoroethylene layer 22 are partially embedded in the polystyrene layer 21 . The thickness of the polystyrene layer 21 is less than 500 nm. The thickness of the polytetrafluoroethylene particle layer 22 is 50-1000 nm.

The protective coatings 100 and 200 can be disposed on the surface of a substrate 30 or the surface of the internal microstructure of the substrate, so as to improve the oxidation resistance, acid and alkali corrosion resistance and strength of the substrate. When the protective coatings 100 and 200 are disposed on the surface of the base body 30 , the polytetrafluoroethylene nanoparticles 23 are bonded through the polyelectrolyte layer 21 or the polystyrene layer 22 and the polyelectrolyte layer 21 On the surface of the base body 30 , the bonding force between the polytetrafluoroethylene nanoparticle layer 22 and the base body 30 is strong.

The matrix can be various fibers and other porous materials, including: filter cloth, filter membrane, filter bag, filter sponge, and the like. More specifically, the filter cloth includes cotton, hemp, polypropylene, polyester, nylon and other filter cloths; the filter bag includes polyphenylene sulfide, polyester, P84, glass fiber, fluoromex, aramid, polypropylene, poly ester and other materials; the filter membrane includes nylon, polytetrafluoroethylene, mixed cellulose ester, polyvinylidene fluoride, microporous filter membrane of glass fiber material, etc.; the filter sponge includes fiber sponge, polyvinyl alcohol, Polyurethane foam sponge, etc.

When the substrate is a filter material substrate, the protective coatings 100 and 200 are arranged on the surface of the filter material substrate and the surface of the filter material substrate fibers. The prepared filter material protective coating has a high coverage rate and can improve the filter material resistance. Oxidation, acid and alkali corrosion resistance, strength; secondly, the prepared filter material fiber protective coating has strong bonding force with fibers, and is resistant to erosion by soot particles; third, the filter material fiber protective coating has low surface energy , with super-hydrophobic properties, good cleaning effect.

The protective coating provided by the invention has the following advantages: firstly, the prepared protective coating has high coverage, which can improve the oxidation resistance, acid and alkali corrosion resistance and strength of the substrate; The bonding force between the substrates is strong; thirdly, the surface energy of the substrate protective coating is low and has super-hydrophobic properties.

Example 1:

Configure mixed solution a to contain 10 g/L of polyelectrolyte and 0.1 mol/L of sodium chloride, and the polyelectrolyte is a mixed solution of polyallylamine hydrochloride and polyvinylamine in a volume ratio of 3:1; The polyphenylene sulfide filter cloth was completely immersed in the mixed solution a, deposited for 15 minutes, then the polyphenylene sulfide filter cloth was taken out from the mixed solution a, and dried with hot air at a temperature of 70 ° C until it was completely dried; take 80 Parts (volume fraction) of polytetrafluoroethylene dispersion with a mass fraction of 4% and 20 parts of a polystyrene dispersion with a mass fraction of 2% are configured as mixed liquid b, and the particle size of the polytetrafluoroethylene nanoparticles is 200nm , the particle size of the polystyrene nanoparticles is 50 nm; the dried polyphenylene sulfide filter cloth is immersed in the mixed solution b, and after standing for 15 minutes, it is thoroughly dried with hot air at a temperature of 70 ° C; Put the polyphenylene sulfide filter cloth into the oven, heat it up to 180 degrees Celsius, bake for 15 minutes, and take it out to cool down naturally. Through scanning electron microscope observation, the fiber surface of the polyphenylene sulfide filter cloth is densely covered with polytetrafluoroethylene nanoparticles, and the coverage rate exceeds 90%, which is much higher than that obtained by traditional polytetrafluoroethylene impregnation technology. The friction test shows that the coating loss rate of the filter material protective coating containing the polystyrene layer under the same positive pressure and the number of reciprocating times is much smaller than that of the filter material protective coating without the polystyrene layer. The surface of the polyphenylene sulfide filter cloth with the filter material protective coating exhibits super-hydrophobic properties, and the cleaning ability is significantly improved.

Example 2

Configure mixed solution a to contain 20 g/L of polyelectrolyte and 0.2 mol/L of sodium chloride, the polyelectrolyte being sodium polystyrene sulfonate and polydiallyl dimethyl ammonium chloride in a volume ratio of 1 : 2 mixed solution; completely immerse the polyester filter cloth in the mixed solution a, deposit it for 15 minutes, take out the polyester filter cloth from the mixed solution a, dry it with hot air at 70°C until it is completely dried; take 70 Part (volume fraction) mass fraction of 5% polytetrafluoroethylene dispersion, 30 parts mass fraction of 1% polystyrene dispersion, configured into mixed solution b, the polytetrafluoroethylene nanoparticle particle size is 200nm , the particle size of the polystyrene nanoparticles is 200 nm; the dried polyester filter cloth is immersed in the mixed solution b, and after standing for 15 minutes, it is thoroughly dried with hot air at a temperature of 70 ° C; the dried polyester filter cloth is Put the cloth in the oven, heat it up to 190 degrees Celsius, bake for 15 minutes, take it out and let it cool down naturally. Through scanning electron microscope observation, the fiber surface of the polyester filter cloth has formed a layer of uniform PTFE nanoparticle porous structure, the pore size is similar to the particle size of polystyrene nanoparticles, and the overall coverage is much higher than that of traditional PTFE. The ethylene impregnation technology is adopted, and the surface of the polyester filter cloth with the filter material protective coating exhibits super-hydrophobic properties, and the cleaning ability is significantly improved.

Example 3

Configure mixed solution a to contain 20 g/L polyelectrolyte and 0.3 mol/L potassium chloride, and the polyelectrolyte is polyvinylamine; completely immerse the polyphenylene sulfide filter cloth in the mixed solution a, deposit For 15 minutes, the polyphenylene sulfide filter cloth was taken out from the mixed solution a, dried with hot air at a temperature of 70° C. until it was completely dried; 100 parts (volume fraction) of a polytetrafluoroethylene dispersion with a mass fraction of 3% were taken, Configured as mixed solution b, and the particle size of the polytetrafluoroethylene nanoparticles is 200 nm; the mixed solution b is evenly sprayed on the surface of the dried polyphenylene sulfide filter cloth with a spray gun, until the polyphenylene sulfide filter cloth is completely soaked. Wet, let stand for 15 minutes and then dry thoroughly with hot air at a temperature of 70°C; put the dried polyphenylene sulfide filter cloth in the oven, heat it up to 180°C, bake for 15 minutes, and take it out to cool down naturally. Through scanning electron microscope observation, the fiber surface of the polyphenylene sulfide filter cloth is densely covered with polytetrafluoroethylene nanoparticles, and the coverage rate exceeds 95%, which is much higher than that obtained by traditional polytetrafluoroethylene impregnation technology.

Example 4

The mixed solution a was configured to contain 15 g/L of polyelectrolyte and 0.5 mol/L of ammonium sulfate, and the polyelectrolyte was polymethacrylic acid; the fiber sponge was completely immersed in the mixed solution a, deposited for 15 minutes, and the The fiber sponge is taken out from the mixed solution a, dried with hot air at a temperature of 70 ° C until it is completely dried; 70 parts (volume fraction) of 5% polytetrafluoroethylene dispersion by mass fraction and 30 parts by mass fraction of 1% polytetrafluoroethylene dispersion are taken. The polystyrene dispersion liquid is configured as mixed liquid b, the particle size of the polytetrafluoroethylene nanoparticles is 200 nm, and the particle size of the polystyrene nanoparticles is 200 nm; the dried fiber sponge is immersed in the mixed liquid In b, after standing for 15 minutes, dry thoroughly with hot air at a temperature of 70°C; put the dried fiber sponge in the oven, heat it up to 200°C, bake for 15 minutes, and take it out to cool down naturally. Through scanning electron microscope observation, the fiber surface of the fiber sponge forms a uniform porous structure of PTFE nanoparticles, the pore size is similar to that of polystyrene nanoparticles, and the overall coverage is much higher than that of traditional PTFE. Impregnation technology, and the surface of the fiber sponge with the filter material protective coating exhibits super-hydrophobic properties and low surface energy.

In addition, those skilled in the art can also make other changes within the spirit of the present invention, and these changes made according to the spirit of the present invention should all be included within the scope of the claimed protection of the present invention.

Claims (9)

1. a kind of protective coating, which is made of a polyelectrolyte layer and a polytetrafluorethylenano nano stratum granulosum, institute It states polyelectrolyte layer and the polytetrafluorethylenano nano stratum granulosum is stacked, the polyelectrolyte layer comprises the following steps: Mixed liquor a is configured, the polyelectrolyte it includes 1~50g/L, the strong electrolyte of 0.01~2mol/L are made；By the mixed liquor a shape It is dried in matrix surface and intrinsic silicon micro-structure, and by the matrix.

2. protective coating as described in claim 1, which is characterized in that the thickness of the polyelectrolyte layer is less than 100nm, described Polytetrafluorethylenano nano stratum granulosum with a thickness of 50~1000nm.

3. a kind of filtrate, which includes filtrate matrix and the protective coating for being set to the filtrate matrix, the protective coating by One polyelectrolyte layer and polytetrafluorethylenano nano stratum granulosum composition, the polyelectrolyte layer and the polytetrafluorethylenano nano Stratum granulosum is stacked, and the polyelectrolyte layer comprises the following steps: configuration mixed liquor a makes gathering it includes 1~50g/L Electrolyte, the strong electrolyte of 0.01~2mol/L；The mixed liquor a is formed in filtrate matrix surface and the filtrate intrinsic silicon Fiber surface, and by the filtrate matrix dry.

4. a kind of matrix, which includes matrix bodies and the protective coating for being set to the matrix bodies, the protective coating by One polyelectrolyte layer and polytetrafluorethylenano nano stratum granulosum composition, the polyelectrolyte layer and the polytetrafluorethylenano nano Stratum granulosum is stacked, and the polyelectrolyte layer comprises the following steps: configuration mixed liquor a makes gathering it includes 1~50g/L Electrolyte, the strong electrolyte of 0.01~2mol/L；The mixed liquor a is formed in inside matrix bodies surface and the matrix bodies In micro-structure, and the matrix bodies are dried.

5. a kind of preparation method of protective coating comprising following steps:

Mixed liquor a is configured, the polyelectrolyte it includes 1~50g/L, the strong electrolyte of 0.01~2mol/L are made；

The mixed liquor a is formed in the surface and intrinsic silicon micro-structure of matrix, and the matrix is dried；

Take the polytetrafluorethylenano nano particle dispersion that 100 parts of mass fraction is 2%~15%；

The polytetrafluorethylenano nano particle dispersion is formed in matrix surface and intrinsic silicon micro-structure, and by the base Body drying；

Being warming up to 160~220 DEG C of bakings solidifies polytetrafluoroethylgranule granule, takes out Temperature fall.

6. the preparation method of protective coating as claimed in claim 5, which is characterized in that the polytetrafluorethylenano nano particle point The partial size of polytetrafluorethylenano nano particle in dispersion liquid is 50~1000 nanometers.

7. the preparation method of protective coating as claimed in claim 5, which is characterized in that described matrix is fiber or porous material Material.

8. a kind of preparation method of filtrate protective coating comprising following steps:

Mixed liquor a is configured, the polyelectrolyte it includes 1~50g/L, the strong electrolyte of 0.01~2mol/L are made；

The mixed liquor a is formed in the fiber surface inside a filter material surface and the filtrate, and the filtrate is dried；

Take the polytetrafluorethylenano nano particle dispersion that 100 parts of mass fraction is 2%~15%；

The polytetrafluorethylenano nano particle dispersion is formed in the fiber surface inside filter material surface and the filtrate, and by institute State filtrate drying；

Being warming up to 160~220 DEG C of bakings solidifies polytetrafluoroethylgranule granule, takes out Temperature fall.

9. the preparation method of filtrate protective coating as claimed in claim 8, which is characterized in that the filtrate be filter cloth, filter membrane, Filter bag or sponge.