阅读说明：本技术 一种乳化水聚结材料及其制备方法和用途 (Emulsified water coalescence material and preparation method and application thereof ) 是由 杨传芳 李艳香 张倩 王莹 李蕾 于 2018-07-23 设计创作，主要内容包括：本发明涉及一种乳化水聚结材料及其制备方法和用途,所述乳化水聚结材料包括基材和涂覆在所述基材表面的含氟聚氨酯涂层。本发明中含氟聚氨酯涂层既含有疏水的含氟链段又具有亲水链段,在空气中具有疏水亲油特性,与水滴接触角为100～120°,与油滴接触角为50～80°,在油下水的接触角呈动态变化,在2min内从120～150°降到50～80°,其为水油乳液中液滴之间的破乳合并提供了有利的条件,相较于现有技术中的其他氟碳材料,对乳化水具有明显更佳的聚结分离效果,适用于含有不同种类、不同浓度表面活性剂的水油乳液的分离,水油分离效率高达91～98％。(The invention relates to an emulsified water coalescent material and a preparation method and application thereof. The fluorinated polyurethane coating disclosed by the invention contains a hydrophobic fluorinated chain segment and a hydrophilic chain segment, has hydrophobic oleophylic characteristics in air, has a contact angle with a water drop of 100-120 degrees, a contact angle with an oil drop of 50-80 degrees, and a contact angle with water under oil is dynamically changed and is reduced from 120-150 degrees to 50-80 degrees within 2min, so that favorable conditions are provided for demulsification and combination of liquid drops in a water-oil emulsion, compared with other fluorocarbon materials in the prior art, the fluorinated polyurethane coating has an obviously better coalescence-separation effect on emulsified water, is suitable for separation of water-oil emulsions containing surfactants of different types and different concentrations, and the water-oil separation efficiency is up to 91-98%.)

1. An emulsified water coalescing material comprising a substrate and a coating layer of a fluorine-containing polyurethane coated on a surface of the substrate.

2. The emulsified water coalescing material according to claim 1, wherein the substrate comprises a filter material;

preferably, the filter material is selected from any one or a combination of at least two of stainless steel felt, cellulose fiber, glass microfiber, glass wool, melt-blown polymer fiber, nylon nanofiber and polyvinylidene fluoride fiber;

preferably, the aperture of the base material is 0.5-20 μm;

preferably, the thickness of the base material is 0.05-100 mm.

3. The emulsified water coalescing material according to claim 1 or 2, wherein-C in the fluorinated polyurethane coating layer_xF_2x+1-and-CH₂CH₂The molar ratio of O < - > is (2-8) to 1, preferably (4-5) to 1;

preferably, x is 2-6.

Preferably, the contact angle of the fluorine-containing polyurethane coating and a water drop is 100-120 degrees.

4. A method of preparing an emulsified water coalescing material according to any one of claims 1 to 3, comprising the steps of:

(1) preparing a fluorine-containing polyurethane emulsion: mixing fluorine-containing alcohol, an organic solvent and a catalyst, adding polyisocyanate, prepolymerizing to obtain a prepolymer, adding a coupling agent and a hydrophilic polymer, continuing to react to obtain a pre-emulsion, adding water to dilute, and removing the organic solvent to obtain a fluorine-containing polyurethane emulsion;

(2) adding a solvent into the fluorinated polyurethane emulsion obtained in the step (1) for dilution to obtain a coating liquid;

(3) and (3) coating the coating liquid obtained in the step (2) on the surface of a base material, and curing to obtain the emulsified water coalescence material.

5. The method of preparing an emulsified water coalescing material according to claim 4, wherein the fluorinated alcohol of step (1) has a formula of X-Y-n (R) -R' OH;

wherein X is a fluoroalkyl chain with 3-10 carbon atoms; y is selected from any one or a combination of at least two of alkylene, alkyleneoxy, sulfenyl or sulfoxy; r and R' are alkyl chains with 1-10 carbon atoms respectively and independently;

preferably, the number of carbon atoms of X is 3-5;

preferably, Y is a sulfoxy group.

6. The method of producing an emulsified water coalescing material according to claim 4 or 5, wherein the organic solvent in step (1) comprises any one of acetone, butanone, cyclohexanone, or 4-methyl-2-pentanone, or a combination of at least two thereof;

preferably, the catalyst of step (1) comprises a tin-containing catalyst, preferably dibutyltin dilaurate and/or dibutyltin diacetate;

preferably, the polyisocyanate of step (1) comprises any one of or a combination of at least two of diphenylmethane diisocyanate, toluene-2, 4-diisocyanate or hexamethylene diisocyanate;

preferably, the prepolymerization conditions in step (1) are as follows: reacting for 1-2 h at 40-80 ℃, preferably for 1-2 h at 50-70 ℃;

preferably, the mass ratio of the fluorine-containing alcohol to the polyisocyanate in the step (1) is (1-6) to (2-8);

preferably, the coupling agent in step (1) comprises a silane coupling agent, preferably any one or a combination of at least two of aminopropyltriethoxysilane, aminoethyltriethoxysilane or aminopropyltrimethoxysilane;

preferably, the hydrophilic polymer in step (1) comprises a polyoxyethylene alcohol hydrophilic polymer, preferably polyethylene glycol or a derivative thereof, further preferably polyethylene glycol monomethyl ether and/or polyethylene glycol dimethyl ether;

preferably, the conditions for continuing the reaction in step (1) are as follows: reacting for 0.5-1 h at 60-80 ℃;

preferably, the mass ratio of the fluorine-containing alcohol to the coupling agent to the hydrophilic polymer in the step (1) is (1-6) to (1-5) to (2-6);

preferably, the water of step (1) comprises deionized water;

preferably, the mass ratio of the fluorine-containing alcohol to the water in the step (1) is (1-6) to (5-8);

preferably, the method for removing the organic solvent in the step (1) comprises rotary evaporation.

7. The method of preparing an emulsified water coalescing material according to any one of claims 4 to 6, wherein the solvent in step (2) comprises an organic solvent and/or water;

preferably, the organic solvent comprises any one of isopropanol, N-dimethylformamide, N-methylpyrrolidone or acetone or a combination of at least two thereof;

preferably, the content of the fluorinated polyurethane emulsion in the coating liquid in the step (2) is 5-30 wt%;

preferably, when the solvent in the step (2) is a mixture of an organic solvent and water, the mass ratio of the organic solvent to the water is 1 (10-17).

8. The method for producing an emulsified water-coalescing material according to any one of claims 4 to 7, wherein the curing in the step (3) is carried out under the following conditions: curing at 60-350 ℃ for 5 min-4 h;

preferably, the curing of step (3) is performed in a drying oven or a muffle furnace.

9. Use of the emulsified water coalescing material according to any one of claims 1 to 3, wherein the emulsified water coalescing material is used for oil-water separation of a diesel emulsion.

10. Use of an emulsified water coalescing material according to claim 9 wherein the diesel emulsion comprises a surfactant, preferably a fat soluble surfactant, further preferably a trimer acid and/or glycerol monooleate;

preferably, the concentration of the surfactant in the diesel oil emulsion is 0-400 ppm;

preferably, the diesel emulsion comprises a diesel emulsion in a diesel engine.

Technical Field

The invention relates to the technical field of oil-water separation materials, in particular to an emulsified water coalescence material and a preparation method and application thereof.

Background

The automotive diesel oil gradually adopts the national V standard, and the sulfur content in the diesel oil is greatly reduced. The diesel oil is subjected to hydrodesulfurization treatment to reduce the lubricity and stability, so that substances with surface activity, such as a lubricant, an antiwear agent, a stabilizer, a preservative and the like, can be artificially added into the ultra-low sulfur diesel oil. When the temperature difference between day and night is large in the process of diesel oil transportation or diesel oil storage, water easily enters into an oil phase, and forms relatively stable emulsified water which is difficult to separate on an engine through shearing of an oil transfer pump and diffusion of a surfactant to an oil-water interface. The surfactant in the diesel oil moves to an oil-water interface, so that the oil-water interfacial tension is reduced, the deformability of the emulsified water is enhanced, and the emulsified water can stably exist in an oil phase. Under the shearing action of high-pressure and low-pressure pumps of diesel engine, the diameter of emulsified water in the diesel oil is about 3-45 micrometers. Since the water drops with the diameter less than 100 μm are difficult to be rapidly settled by the action of gravity, the emulsified water after shearing can be stably dispersed in the oil phase, and the difficulty of oil-water separation is increased. In a compression ignition system of a diesel engine, a high-pressure common rail system with the pressure of 200MPa sprays fuel into a combustion chamber to be fully combusted, and a fuel injection nozzle is only 2-5 mu m, so that the existence of emulsified water can cause corrosion and blockage of the fuel injection nozzle, reduce the self lubricating property of diesel oil and shorten the service life of the engine. In addition, under cold conditions, the emulsified water freezes to ice, causing clogging of the particulate filter, resulting in engine misfire due to fuel not reaching the combustion chamber, and therefore, it is important to remove the emulsified water from the diesel fuel.

The oil-water separation mainly adopts the methods of gravity settling, centrifugation, distillation, coalescence separation and the like. The gravity settling can not separate the emulsified water on the diesel engine in time, the centrifugal separation operation is inconvenient and has high cost, and the distillation and other means can not be used on the engine, so the oil-water separation on the engine is usually simple and low-cost coalescence separation or screening separation or the combination of the two. These separation materials are usually made of natural or synthetic fibers, or a mixture of both, by different technical means. The coalescence separation method uses a porous material with deep filtration to coalesce small drops of emulsified water in the diesel oil, and then realizes oil-water separation by a gravity settling method. According to the coalescence-separation principle, when the contact angle between emulsified water and the surface of the coalescence material is between 90 and 140 degrees, water drops can roll on the solid surface, and the water drops collide with each other, coalesce and grow, and are released along the flowing direction of diesel oil. The radius of the water drops after coalescence is more than 100 μm, the water drops sink under the action of gravity, and oil-water separation is realized by the density difference of two phases.

CN105964014B discloses that spraying a dopamine-mediated layer on a stainless steel net to perform amidation coupling reaction, so that a stable hydrophilic polymer film is formed on the surface of the stainless steel net, and the method has a remarkable effect on oil-water separation, but the influence of the type and concentration of a surfactant on the stability of an oil-water emulsion is not considered.

CN105926020B discloses super-hydrophilic titanium foam for oil-water separation, which has remarkable oil-water separation effect, but does not consider the problem that the existence of a surfactant at an oil-water interface is not beneficial to oil-water separation.

In the water-oil-solid system, the surfactant is free to move in the oil phase and self-assembles to form micelles at higher concentrations. When water drops enter the oil phase, the surfactant can move to the oil-water interface, and the tension of the oil-water interface is reduced. During filtration, the emulsion contacts the surface of the filtering solid, the surfactant can be adsorbed on the surface of the solid, and the adsorption of the surfactant on the surface of the solid can weaken the action of the surfactant on the oil-water interface. In the current oil-water separation example, the effect of specific analysis of the surfactant on oil-water separation is less studied.

Therefore, there is a need for the development of an emulsified water coalescing material that efficiently separates emulsified water from a surfactant-containing oil-water emulsion.

Disclosure of Invention

In view of the problems of the prior art, it is an object of the present invention to provide an emulsified water coalescing material that efficiently separates emulsified water in a surfactant-containing oil-water emulsion.

In order to achieve the purpose, the invention adopts the following technical scheme:

in a first aspect, the present invention provides an emulsified water coalescing material comprising a substrate and a coating layer of a fluorinated polyurethane coated on a surface of the substrate.

The essence of the fluorinated polyurethane coating is that a fluorinated carbon chain is introduced into organic polymer polyurethane, the fluorinated polyurethane coating contains a hydrophobic fluorinated chain segment and a hydrophilic chain segment, the material shows special physical and chemical properties, the surface energy is obviously lower than that of the polyurethane, and emulsified water shows a special wetting phenomenon on the fluorinated polyurethane coating, thereby being beneficial to coalescence and separation of a surfactant-containing dispersion liquid. Under oil, the wettability change of water drops on the surface and the adsorption effect of the water drops on the surface of the water drops on the surfactant provide favorable conditions for demulsification and combination among the water drops, and particularly greatly improve the oil-water separation efficiency of the surfactant with higher concentration.

The term "comprising" as used herein means that it may include, in addition to the components, other components which impart different characteristics to the emulsified water-containing coalescing material. In addition, the term "comprising" as used herein may be replaced by "being" or "consisting of … …" as closed.

The following technical solutions are preferred but not limited to the technical solutions provided by the present invention, and the technical objects and advantages of the present invention can be better achieved and realized by the following technical solutions.

Preferably, the substrate comprises a filter material.

Preferably, the filter material is selected from any one or a combination of at least two of stainless steel felt, cellulose fiber, glass microfiber, glass wool, melt-blown polymer fiber, nylon nanofiber and polyvinylidene fluoride fiber; for example, a pure cellulose fiber filter medium, a glass microfiber or glass wool filter medium, a mixed filter medium of cellulose fibers and micron-sized glass fibers or glass wool, a self-supporting melt-blown PET or PBT filter medium, a composite material of melt-blown PET/PBT and a cellulose fiber filter medium, a composite filter medium of melt-blown PET/PBT and glass microfibers, a composite filter medium of melt-blown PET/PBT and cellulose fibers and glass microfibers, other melt-blown polymer fine fiber filter media, a composite porous filter medium formed by electrospinning nylon nanofibers, polyvinylidene fluoride fibers and other filter media.

Preferably, the pore size of the substrate is 0.5 to 20 μm, such as 0.5 μm, 1 μm, 2 μm, 5 μm, 8 μm, 10 μm, 12 μm, 15 μm, 18 μm, or 20 μm.

Preferably, the substrate has a thickness of 0.05 to 100mm, such as 0.05mm, 0.1mm, 0.5mm, 1mm, 2mm, 5mm, 10mm, 20mm, 50mm, 80mm, or 100mm, and the like.

Preferably, -C in the fluorine-containing polyurethane coating_xF_2x+1- (fluorine-containing repeating segment) and-CH₂CH₂The molar ratio of O- (ethoxy repeating segment) is (2-8): 1, for example, 2:1, 3:1, 4:1, 5:1, 6:1, 7:1 or 8:1, and preferably (4-5): 1.

Preferably, the contact angle between the fluorine-containing polyurethane coating and a water drop is 100-200 degrees, such as 100 degrees, 110 degrees, 120 degrees, 130 degrees, 140 degrees, 150 degrees, 160 degrees, 170 degrees, 180 degrees, 190 degrees or 200 degrees.

In a second aspect, the present invention provides a method for preparing an emulsified water coalescing material according to the first aspect, comprising the steps of:

(1) preparing a fluorine-containing polyurethane emulsion: mixing fluorine-containing alcohol, an organic solvent and a catalyst, adding polyisocyanate, prepolymerizing to obtain a prepolymer, adding a coupling agent and a hydrophilic polymer, continuing to react to obtain a pre-emulsion, adding water to dilute, and removing the organic solvent to obtain a fluorine-containing polyurethane emulsion;

(2) adding a solvent into the fluorinated polyurethane emulsion obtained in the step (1) for dilution to obtain a coating liquid;

(3) and (3) coating the coating liquid obtained in the step (2) on the surface of a base material, and curing to obtain the emulsified water coalescence material.

Preferably, the fluorine-containing alcohol in the step (1) has a structural formula of X-Y-N (R) -R' OH;

wherein X is a fluoroalkyl chain having 3-10 carbon atoms, and the number of carbon atoms can be 3, 4, 5, 6, 7, 8, 9 or 10; y is selected from any one or a combination of at least two of alkylene, alkyleneoxy, sulfenyl or sulfoxy; r and R' are alkyl chains with 1-10 carbon atoms, and the number of the carbon atoms can be 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10. Wherein, the fluorine-containing alcohol is short-chain alcohol without biological accumulated toxicity, and Y is used as a transition group to adjust the connection characteristic between the fluorine-containing chain segment and the main chain segment and optimize the separation effect of the oil-water emulsion.

Preferably, the number of carbon atoms of X is 3 to 5.

Preferably, Y is sulfoxy;

preferably, the organic solvent in step (1) comprises any one or a combination of at least two of acetone, butanone, cyclohexanone or 4-methyl-2-pentanone, wherein typical but non-limiting combinations are: a combination of acetone and butanone, a combination of cyclohexanone and 4-methyl-2-pentanone, a combination of acetone, butanone and cyclohexanone, a combination of butanone, cyclohexanone and 4-methyl-2-pentanone, a combination of acetone, butanone, cyclohexanone and 4-methyl-2-pentanone;

preferably, the catalyst of step (1) comprises a tin-containing catalyst, preferably dibutyltin dilaurate and/or dibutyltin diacetate.

Preferably, the polyisocyanate of step (1) comprises any one of diphenylmethane diisocyanate (MDI), toluene-2, 4-diisocyanate (TDI) or Hexamethylene Diisocyanate (HDI) or a combination of at least two thereof; typical but non-limiting combinations among these are: the combination of MDI and TDI, the combination of MDI and HDI, the combination of TDI and HDI, the combination of MDI, TDI and HDI, or the dimer, trimer and the like of MDI, TDI and HDI. The degree of reaction progress and the structure of the synthesized product can be controlled by adjusting the percentage content of NCO groups in the polyisocyanate.

Preferably, the prepolymerization conditions in step (1) are as follows: reacting at 40-80 ℃ for 1-2 h, for example, the prepolymerization temperature is 40 ℃, 42 ℃, 45 ℃, 48 ℃, 50 ℃, 55 ℃, 60 ℃, 65 ℃, 70 ℃, 75 ℃ or 80 ℃, and the like, and the time is 1h, 1.2h, 1.5h, 1.8h or 2h, and the like; preferably 50-70 ℃ for 1-2 h.

Preferably, in the step (1), the mass ratio of the fluorine-containing alcohol to the polyisocyanate is (1-6) to (2-8), for example, 1:2, 1:5, 1:8, 3:2, 3:3, 3:8, 6:2, 6:5, or 6: 8.

Preferably, the coupling agent in step (1) comprises a silane coupling agent, preferably any one or a combination of at least two of aminopropyltriethoxysilane, aminoethyltriethoxysilane or aminopropyltrimethoxysilane; typical but non-limiting combinations among these are: aminopropyltriethoxysilane in combination with aminoethyltriethoxysilane, aminopropyltriethoxysilane in combination with aminopropyltrimethoxysilane, aminoethyltriethoxysilane in combination with aminopropyltrimethoxysilane, preferably aminopropyltriethoxysilane, aminoethyltriethoxysilane in combination with aminopropyltrimethoxysilane.

Preferably, the hydrophilic polymer in step (1) comprises a polyoxyethylene alcohol hydrophilic polymer, preferably polyethylene glycol or a derivative thereof, further preferably polyethylene glycol monomethyl ether and/or polyethylene glycol dimethyl ether.

Preferably, the conditions for continuing the reaction in step (1) are as follows: reacting for 0.5-1 h at 60-80 ℃; for example, the reaction temperature is 60 ℃, 62 ℃, 65 ℃, 68 ℃, 70 ℃, 72 ℃, 75 ℃, 78 ℃ or 80 ℃, and the reaction time is 0.5h, 0.6h, 0.7h, 0.8h, 0.9h or 1 h.

Preferably, in the step (1), the mass ratio of the fluorine-containing alcohol to the coupling agent to the hydrophilic polymer is (1-6): (1-5): 2-6, for example, 1:1:2, 1:5:2, 1:1:6, 1:5:6, 2:3:2, 2:5:4, 6:1:2, 6:5:2, 6:1:6, or 6:5: 2.

Preferably, the water of step (1) comprises deionized water.

Preferably, in the step (1), the mass ratio of the fluorine-containing alcohol to the water is (1-6) to (5-8), for example, 1:5, 1:7, 1:8, 3:5, 3:8, 6:5, 6:6, or 6: 8.

Preferably, the method for removing the organic solvent in the step (1) comprises rotary evaporation.

Preferably, the solvent of step (2) comprises an organic solvent and/or water.

Preferably, the organic solvent comprises any one of isopropanol, N-dimethylformamide, N-methylpyrrolidone or acetone, or a combination of at least two thereof, wherein typical but non-limiting combinations are: a combination of isopropanol and N, N-dimethylformamide, a combination of N-methylpyrrolidone and acetone, a combination of isopropanol, N-dimethylformamide and N-methylpyrrolidone, a combination of isopropanol, N-dimethylformamide, N-methylpyrrolidone and acetone.

Preferably, the content of the fluorinated polyurethane emulsion in the coating liquid of step (2) is 5 to 30 wt%, such as 5 wt%, 8 wt%, 10 wt%, 12 wt%, 15 wt%, 18 wt%, 20 wt%, 22 wt%, 25 wt%, 28 wt%, or 30 wt%.

Preferably, when the solvent in the step (2) is a mixture of an organic solvent and water, the mass ratio of the organic solvent to the water is 1 (10-17), such as 1:10, 1:11, 1:12, 1:13, 1:14, 1:15, 1:16, or 1: 17.

Preferably, the curing conditions in step (3) are as follows: curing at 60-350 ℃ for 5 min-4 h; for example, the curing temperature is 60 ℃, 80 ℃, 100 ℃, 120 ℃, 150 ℃, 180 ℃, 200 ℃, 220 ℃, 250 ℃, 280 ℃, 300 ℃, 320 ℃ or 350 ℃, and the curing time is 5min, 15min, 30min, 45min, 1h, 1.5h, 2h, 2.5h, 3h, 3.5h or 4 h.

Preferably, the curing of step (3) is performed in a drying oven or a muffle furnace.

As a preferable technical scheme of the invention, the preparation method of the emulsified water coalescence material comprises the following steps:

(1) preparing a fluorine-containing polyurethane emulsion: mixing fluorine-containing alcohol, an organic solvent and a catalyst, adding polyisocyanate, and carrying out prepolymerization reaction at 40-80 ℃ for 1-2 h to obtain a prepolymer, wherein the structural formula of the fluorine-containing alcohol is X-Y-N (R) -R' OH; x is a fluoroalkyl chain with 3-10 carbon atoms; y is selected from any one or a combination of at least two of alkylene, alkyleneoxy, sulfenyl or sulfoxy; r and R' are alkyl chains with 1-10 carbon atoms respectively and independently; the polyisocyanate comprises any one or the combination of at least two of diphenylmethane diisocyanate, toluene-2, 4-diisocyanate or hexamethylene diisocyanate; the mass ratio of the fluorine-containing alcohol to the polyisocyanate is (1-6) to (2-8);

adding a coupling agent and a hydrophilic polymer, wherein the hydrophilic polymer comprises polyethylene glycol or derivatives thereof, reacting for 0.5-1 h at 60-80 ℃ to obtain a pre-emulsion, diluting with water, and removing an organic solvent by rotary evaporation to obtain a fluorinated polyurethane emulsion, wherein the mass ratio of fluorinated alcohol to hydrophilic polymer is (1-6) - (1-5) - (2-6);

(2) adding a solvent into the fluorinated polyurethane emulsion obtained in the step (1) for dilution to obtain a coating liquid, wherein the content of the fluorinated polyurethane emulsion in the coating liquid is 5-30 wt%;

(3) and (3) coating the coating liquid obtained in the step (2) on the surface of a base material, and curing for 5 min-4 h at the temperature of 60-350 ℃ in a drying box or a muffle furnace to obtain the emulsified water coalescence material.

In a third aspect, the present invention provides the use of an emulsified water coalescing material according to the first aspect for oil-water separation of a diesel emulsion.

Preferably, the diesel oil emulsion contains a surfactant, preferably a fat-soluble surfactant, and further preferably a high-purity trimer acid and/or glycerol monooleate. The fluorine-containing polyurethane coating can enhance the adsorption of the surfactant in the diesel on the surface of the material and ensure that the surface has special wettability to water under oil. Under the condition of 0-400 ppm of surfactant concentration, the emulsified water coalescence material still has high separation efficiency.

Preferably, the concentration of surfactant in the diesel emulsion is 0 to 400ppm, such as 0ppm, 10ppm, 20ppm, 50ppm, 100ppm, 150ppm, 200ppm, 250ppm, 300ppm, 350ppm, 400ppm, or the like.

Preferably, the diesel emulsion comprises a diesel emulsion in a diesel engine.

Compared with the prior art, the invention has at least the following beneficial effects:

1. the fluorinated polyurethane coating disclosed by the invention contains a hydrophobic fluorinated chain segment and a hydrophilic chain segment, has hydrophobic oleophylic characteristics in air, has a contact angle with a water drop of 100-120 degrees, a contact angle with an oil drop of 50-80 degrees, and a contact angle with water under oil is dynamically changed and is reduced from 120-150 degrees to 50-80 degrees within 2min, so that favorable conditions are provided for demulsification and combination among liquid drops in a water-oil emulsion, and compared with other fluorocarbon materials in the prior art, the fluorinated polyurethane coating has an obviously better coalescence-separation effect on emulsified water;

2. due to the fluorinated polyurethane coating, the emulsified water coalescence material is suitable for separating water-oil emulsions containing different types of surfactants with different concentrations, and the water-oil separation efficiency is up to 91-98%;

3. the fluorinated polyurethane coating has water-repellent and anti-fouling effects to a certain extent, so that the fluorinated polyurethane coating has a self-cleaning effect and has potential application in the fields of building industry, daily use and the like;

4. the raw materials used in the preparation method are easy to degrade in nature, and the product is green and environment-friendly.

Drawings

FIG. 1 is an SEM photograph of a stainless steel felt coated with a fluorinated polyurethane coating in example 1 of the present invention;

FIG. 2 is an SEM image of an uncoated stainless steel felt of comparative example 1 of the present invention;

FIG. 3 is a SEM photograph at a low magnification showing the surface of the fluorine-containing polyurethane coating layer in example 1 of the present invention;

FIG. 4 is a SEM photograph at a high magnification showing the surface of the fluorine-containing polyurethane coating layer in example 1 of the present invention;

FIG. 5 is a contact angle of a water droplet on the surface of a fluorine-containing polyurethane coating layer in example 1 of the present invention;

FIG. 6 is a graph showing contact angle change curves of emulsified water drops in diesel fuel containing 200ppm of glyceryl monooleate according to the present invention on the surfaces of the coatings of example 1, comparative example 2 and comparative example 4;

FIG. 7 is a graph comparing the separation efficiency of emulsified water from ultra low sulfur diesel fuel containing different concentrations of high purity trimer acid with emulsified water coalescent materials of example 1, comparative example 2, and comparative example 4 according to the present invention;

FIG. 8 is a graph showing the separation efficiency of the emulsified water coalescer according to the present invention in ultra low sulfur diesel fuel containing glycerol monooleate at various concentrations in example 1, comparative example 2 and comparative example 4.

Detailed Description

The technical scheme of the invention is further explained by the specific implementation mode in combination with the attached drawings. The following examples are merely illustrative of the present invention and do not represent or limit the scope of the claims, which are defined by the claims.

In the specific implementation mode of the invention, the oil-water separation efficiency of each example and each comparative example is measured by the following method:

a diesel oil emulsion was prepared using apparatus EMCEE MSEP (ASTM D7261) and subjected to a filtration experiment, and 50. mu.L of ultrapure water was added to 50mL of surfactant-containing diesel oil in a 60mL syringe, and stirred at a high speed of 25000r/min to give a diesel oil emulsion having a droplet size of 4 to 35 μm. The emulsified water coalescing materials of each example and comparative example were separately placed in a filter, and the filter was mounted on the head of a syringe, which was then placed on a holder of an EMCEE device. When the EMCEE equipment is operated, the lever pushes the plunger piston to enable the emulsion to pass through the stainless steel felt containing the coating, and the filtered diesel oil is obtained. The filtrate was collected and the water content of the filtrate was measured using a karl fischer moisture analyzer. The oil-water separation efficiency was calculated from the following formula:

wherein, C₀Is the initial mass fraction of water in the oil phase, C_fIs the mass fraction of water not separated in the filtrate.