A method for preparing wax-resistant oil coating

Abstract

The present invention relates to a kind of preparation method of anti-wax oil coating, water is added in phosphoric acid, aluminum hydroxide particles are added, high temperature stirring, reaction forms transparent viscous liquid, is cooled to room temperature, namely obtains high temperature adhesive aluminum dihydrogen phosphate;By obtained high temperature adhesive aluminum dihydrogen phosphate in dissolved water, add aqueous polyvinylidene fluoride emulsion, magnetic agitation obtains solution A, fluorinated nano silicon dioxide and polyimide powder are sequentially added in dehydrated alcohol, magnetic agitation, ultrasonic, obtain solution B, then solution B is poured into solution A, obtain solution C, magnetic agitation, ultrasonic, complete spraying liquid;Uniformly sprayed on nickel foam, namely obtain anti-wax oil coating after having sprayed and dried.The substrate surface of coating of the present invention shows super oleophobic property, and its contact angle for oil is greater than 150 °, and rolling angle is less than 10 °, and the substrate after coating has preferably wear resistance, self-cleaning, high temperature resistant and weak acid and alkali corrosion.

Description

Technical Field

[0001] The present invention relates to the technical field of oleophobic material preparation, and in particular to a method for preparing a wax-resistant oil coating. Background Art

[0002] With the development of superhydrophobic surfaces, the demand for oleophobic surfaces is also increasing. Compared to water, oil has a lower surface energy and higher viscosity. Water can form droplets on the surface of a lotus leaf, while oil cannot. Therefore, it is relatively easy to achieve superhydrophobicity in some biomimetic materials. However, the conditions for achieving oleophobicity are more demanding than those for hydrophobicity. The two key factors in constructing oleophobic materials today are the construction of micro-nano composite roughness structures and the modification of low-surface-energy materials.

[0003] Wax oil is a complex mixture of oils. At higher temperatures, it is liquid. As the temperature drops, the waxy components begin to crystallize and precipitate, gradually becoming viscous and finally solid. When transporting waxy oils through pipelines, the wax deposits on the cooler pipe walls. This deposition can cause excessive pipeline pressure, reduced transport efficiency, blockages, and frequent cleaning.

[0004] Wax-resistant coatings are ideal for oil pipelines and other areas requiring oil pollution control. They significantly reduce wax deposition in oil pipelines, extending cleaning cycles, reducing cleaning frequency, lowering maintenance costs, and preventing pipeline blockages. Furthermore, wax-resistant coatings exhibit excellent high-temperature resistance, enabling them to operate continuously in high-temperature oil pipelines. The coating's oleophobic and superhydrophobic properties maintain a self-cleaning surface while also resisting certain weak acid and alkali corrosion. Therefore, wax-resistant coatings play a significant role in protecting oil pipelines and ensuring safe transportation. Summary of the Invention

[0005] In view of the problems existing in the prior art, the present invention provides a polysaccharide-polydopamine-based coated probiotic and a method for preparing the same. The natural polysaccharide-polydopamine-based coated probiotic is encapsulated in a uniform, dense polymer coating, exhibiting superior resistance to the gastrointestinal environment and excellent resistance to damage from gastric acid, digestive enzymes, and bile salts. The present invention also provides a method for preparing the natural polysaccharide-polydopamine-based coated probiotic. This method utilizes the oxidative autopolymerization of dopamine to co-deposit the natural polysaccharide with dopamine on the surface of the probiotic, forming a uniform, dense coating.

[0006] The present invention is achieved through the following technical solutions:

[0007] A method for preparing a wax-resistant oil coating, the method comprising the following steps:

[0008] 1) Preparation of high-temperature adhesive aluminum dihydrogen phosphate: Add water to phosphoric acid and stir evenly. Then add aluminum hydroxide particles and stir at high temperature to react to form a transparent viscous liquid. Finally, cool to room temperature to obtain the high-temperature adhesive aluminum dihydrogen phosphate.

[0009] 2) Fluorination modification of nano-silica: Place nano-silica particles in a mixed solution of a fluorinated modifier and n-hexane, stir evenly, and allow the solution to evaporate naturally. Finally, wash with anhydrous ethanol and dry to obtain fluorinated nano-silica.

[0010] 3) Preparation of the spraying liquid: Dissolve the high-temperature adhesive aluminum dihydrogen phosphate prepared in step 1) in water, and then magnetically stir the aqueous polyvinylidene fluoride emulsion to obtain solution A. Add the fluorinated nano-silica and polyimide powder prepared in step 2) to anhydrous ethanol in sequence, magnetically stir, and ultrasonically process to obtain solution B. Then, pour solution B into solution A to obtain solution C, magnetically stir, and ultrasonically process to complete the spraying liquid.

[0011] 4) Preparation of the base coating: Cut the nickel foam into sheets, ultrasonically clean them with anhydrous ethanol and deionized water to remove impurities, dry them in a drying oven, and then evenly spray the spray liquid prepared in step 3) on the nickel foam using a spray gun. After spraying and drying, the wax-resistant coating is obtained.

[0012] Preferably, in step 1), the molar ratio of aluminum hydroxide particles to phosphoric acid is 1:(3-3.2), the mass fraction of phosphoric acid is 85%, the high-temperature stirring temperature is 120-130° C., and the high-temperature stirring time is 20-30 min.

[0013] High temperature stirring can be achieved by constant temperature magnetic stirring or oil bath stirring.

[0014] Preferably, in step 2), the particle size of the nano-silica particles is 30 + 5nm, mass is 1~1.2g.

[0015] Preferably, in step 2), the fluorinated modifier is perfluorooctyltrichlorosilane, and the mass concentration of the perfluorooctyltrichlorosilane / n-hexane mixed solution is 0.5% to 1%. Perfluorodecyltrichlorosilane or perfluorodecyltriethoxysilane may also be used as the fluorinated modifier.

[0016] Preferably, in step 2) and step 3), the solid-liquid ratio of high-temperature adhesive: water: polyvinylidene fluoride emulsion: fluorinated silica: polyimide: anhydrous ethanol is (1-2): (3-5): (2-3): (0.4-0.5): (0.2-0.4): (12-15) g / ml / g / g / g / ml.

[0017] Preferably, in step 3), the magnetic stirring time is 5-10 min, the stirring speed is 900-1000 r / min, the ultrasonic time is 3-5 min, the ultrasonic power is 75-80 W, the ultrasonic frequency is 35-45 kHz, and the two magnetic stirring and ultrasonic settings are the same.

[0018] Preferably, in step 4), the nickel foam has a thickness of 0.5 mm, a pore size of 0.1 mm, a porosity of 97.2%, and a PPI of 110. The nickel foam substrate can also be made of stainless steel mesh or glass sheet, as the special roughness of the surface of the nickel foam and stainless steel mesh provides better results.

[0019] Preferably, in step 4), the ultrasonic cleaning time of anhydrous ethanol and deionized water is 5-15 minutes, the ultrasonic power is 75-85W, the ultrasonic frequency is 35-45KHz, the drying temperature of the drying oven is 55-65°C, and the drying time is 10-30 minutes.

[0020] Preferably, in step 4), the spraying pressure of the spray gun is 0.4-0.5 MPa, and the spraying distance is 20-25 cm. A uniform spraying method is to spray for 1 second, then blow air with the spray gun for 5 seconds, and finally dry in a muffle furnace at 100°C for 5 seconds. Repeat the previous steps until the substrate is evenly coated.

[0021] Preferably, in step 4), the baking temperature in the muffle furnace is first 100°C for 7-10 hours, then 115-125°C for 1.5-2.5 hours, and finally 230-250°C for 0.5-1.5 hours.

[0022] The present invention has the following beneficial effects:

[0023] The present invention provides a method for preparing a wax-resistant oil coating that is simple to prepare, easy to use, and widely applicable, overcoming the high cost, complex manufacturing process, and limited applicability of most commercially available oleophobic coatings. The fluorinated nano-silica powder exhibits stable oleophobicity even at high temperatures. The aluminum dihydrogen phosphate prepared from the nano-silica powder serves as a high-temperature adhesive, and the nanoparticles form a unique micro-nano composite rough structure with an oil contact angle greater than 150° and a rolling angle less than 10°, resulting in excellent oleophobicity, high-temperature resistance, and self-cleaning properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is an optical photograph of the contact angles of water and molten wax oil of the foamed nickel anti-wax oil coating in Example 1.

[0025] Figure 2 These are scanning electron microscope images of the original nickel foam and the prepared nickel foam coating in Example 1.

[0026] Figure 3 This is an optical photograph of the foamed nickel anti-wax oil coating of Example 1 immersed in molten wax oil.

[0027] Figure 4 This is an optical photograph of the dynamic contact between water and edible blended oil of the foamed nickel anti-wax oil coating in Example 1.

[0028] Figure 5 This is an optical photograph of the wettability of the stainless steel mesh's anti-wax coating with molten wax oil in Example 2.

[0029] Figure 6 This is an optical photograph of the contact angles of water and molten wax oil on the wax-resistant coating on the glass sheet in Example 3.

[0030] Figure 7 This is a data diagram of the wax oil rolling angle of the wax oil-resistant coating on the glass sheet of Example 3 at different temperatures.

[0031] Figure 8 These are optical photographs of the wax-resistant coating on the glass sheet in Example 3, showing the wax starting to roll off at different temperatures.

[0032] Figure 9 This is an optical photograph of the solidification-melting-rolling behavior of the wax oil on the anti-wax oil coating on the glass sheet in Example 3. DETAILED DESCRIPTION

[0033] In order to enable those skilled in the art to better understand the present invention and implement it, the present invention is further described below with reference to the accompanying drawings and specific embodiments, but the embodiments are not intended to limit the present invention.

[0034] Example 1

[0035] (1) Preparation of high temperature adhesive:

[0036] 8.8 g of phosphoric acid (85% by mass) and 5 g of water were added to a beaker in sequence and stirred evenly. 2 g of aluminum hydroxide particles were then weighed and added thereto. The mixed solution was placed in a constant temperature magnetic stirrer at 120°C for 20 minutes. After cooling to room temperature, a transparent viscous liquid was obtained, thereby completing the preparation of the high-temperature adhesive.

[0037] (2) Fluorination of nano-silica:

[0038] 1g of nano-silicon dioxide (particle size 30 +5nm) was soaked in 40ml of a 0.5wt%-1wt% perfluorooctyltrichlorosilane n-hexane solution, stirred evenly, and allowed to evaporate naturally. The remaining fluorinated nano-silica powder was washed twice with anhydrous ethanol, filtered, and then dried in a 60°C oven for 30 minutes to complete the chemical modification of the nano-silica.

[0039] (3) Preparation of spraying liquid:

[0040] Take 1.5g of the high-temperature adhesive prepared in step (1) and dissolve it in 3.5ml of water, add 2.5g of aqueous polyvinylidene fluoride emulsion, and stir it with a magnetic stirrer for 10min. The resulting solution is named solution A. Take 0.4g of fluorinated nano-silica and 0.2g of polyimide powder prepared in step (2) and add them to 14ml of anhydrous ethanol. Stir it magnetically for 10min and ultrasonicate it for 3min. The resulting solution is named solution B. Then, solution B is slowly poured into solution A. The mixed solution is named solution C. Solution C is magnetically stirred for 10min and ultrasonicated for 3min to complete the preparation of the spray liquid.

[0041] (4) Preparation of coating:

[0042] Cut the nickel foam into 2x2cm sheets, ultrasonically clean them with anhydrous ethanol and deionized water for 10 minutes in sequence to remove impurities, and then dry them in a 60℃ drying oven for 10 minutes. Then use a spray gun to evenly spray the spray liquid prepared in step (3) on the nickel foam at a pressure of 0.4MPa, with a spray distance of 15cm, and the spraying is completed. Then place the coating sample in a muffle furnace at 100℃ for heat treatment for 7 hours, then increase the baking temperature to 120℃ for 2 hours, and finally increase the temperature to 240℃ for 1 hour. Cool to room temperature to obtain a wax-resistant coating. The contact angle of water and molten wax oil of the obtained coating is shown in the figure below. Figure 1 As shown in the figure, the contact angle of water (room temperature) on the coating is measured to be 158.2°, and the contact angle of molten wax oil (70°C) is 151.5°. Figure 2 The scanning electron microscope images of the original nickel foam and the prepared nickel foam show that the anti-wax and oil coating has constructed a nano-scale structure on the micro-scale rough structure of the nickel foam. Figure 3 It can be seen that the foamed nickel wax-resistant coating cannot be wetted at all even when soaked in molten wax, and has excellent wax-resistant properties. Figure 4 This is a dynamic contact picture of water and edible blended oil. It can be seen from the picture that the foam nickel anti-wax and oil coating has very low adhesion to water and oil.

[0043] Example 2

[0044] (1) Preparation of high temperature adhesive:

[0045] 8.8 g of phosphoric acid (85% by mass) and 5 g of water were added to a beaker in sequence and stirred evenly. 2 g of aluminum hydroxide particles were then weighed and added thereto. The mixed solution was placed in a constant temperature magnetic stirrer at 120°C for 20 minutes. After cooling to room temperature, a transparent viscous liquid was obtained, thereby completing the preparation of the high-temperature adhesive.

[0046] (2) Fluorination of nano-silica:

[0047] Soak 1g of nanosilica (particle size 30–5nm) in 40ml of a 0.5–1wt% perfluorooctyltrichlorosilane n-hexane solution, stir evenly, and allow the solution to evaporate naturally. Wash the remaining fluorinated nanosilica powder twice with anhydrous ethanol, filter, and dry in a 60°C oven for 30 minutes to complete the fluorination.

[0048] (3) Preparation of spraying liquid:

[0049] Take 1.5g of the high-temperature adhesive prepared in step (1) and dissolve it in 3.5ml of water. Add 2.5g of aqueous polyvinylidene fluoride emulsion and stir it with a magnetic stirrer for 10min. The resulting solution is named solution A. Take 0.4g of fluorinated nano-silica and 0.2g of polyimide powder prepared in step (2) and add them to 14ml of anhydrous ethanol. Stir it magnetically for 10min and ultrasonicate it for 3min. The resulting solution is named solution B. Then slowly pour solution B into solution A. The mixed solution is named solution C. Stir solution C magnetically for 10min and ultrasonicate it for 3min to complete the preparation of the spray liquid.

[0050] (4) Preparation of coating:

[0051] Cut the stainless steel mesh into 2x2cm pieces and ultrasonically clean them in anhydrous ethanol and deionized water for 10 minutes to remove impurities. Then, dry them in a 60℃ drying oven for 10 minutes. Then, use a spray gun to evenly spray the spray liquid prepared in step (3) on the stainless steel mesh at a pressure of 0.4MPa and a spray distance of 15cm. The coating sample is then heat-treated in a muffle furnace at 100℃ for 7 hours. The baking temperature is then increased to 120℃ for 2 hours, and finally increased to 240℃ for 1 hour. Cool to room temperature to obtain the wax-resistant coating. Figure 5 This is a picture of the wettability of molten wax oil on the anti-wax oil coating of the stainless steel mesh. It can be seen from the picture that the molten wax oil (70℃) is in a spherical shape on the anti-wax oil coating. The anti-wax oil coating of the stainless steel mesh has good anti-wax oil performance.

[0052] Example 3

[0053] (1) Preparation of high temperature adhesive:

[0054] 8.8 g of phosphoric acid (85% by mass) and 5 g of water were added to a beaker in sequence and stirred evenly. 2 g of aluminum hydroxide particles were then weighed and added thereto. The mixed solution was placed in a constant temperature magnetic stirrer at 120°C for 20 minutes. After cooling to room temperature, a transparent viscous liquid was obtained, thereby completing the preparation of the high-temperature adhesive.

[0055] (2) Fluorination of nano-silica:

[0056] Soak 1g of nano-silica (particle size 30-5nm) in 40ml of a 0.5wt%-1wt% perfluorooctyltrichlorosilane n-hexane solution, stir evenly, and allow the solution to evaporate naturally. Wash the remaining fluorinated nano-silica powder twice with anhydrous ethanol, filter, and dry in a 60°C oven for 30 minutes to complete the fluorination of the silica.

[0057] (3) Preparation of spraying liquid:

[0058] Take 1.5g of the high-temperature adhesive prepared in step (1) and dissolve it in 3.5ml of water. Add 2.5g of aqueous polyvinylidene fluoride emulsion and stir it with a magnetic stirrer for 10min. The resulting solution is named solution A. Take 0.4g of fluorinated nano-silica and 0.2g of polyimide powder prepared in step (2) and add them to 14ml of anhydrous ethanol. Stir it magnetically for 10min and ultrasonicate it for 3min. The resulting solution is named solution B. Then slowly pour solution B into solution A. The mixed solution is named solution C. Stir solution C magnetically for 10min and ultrasonicate it for 3min to complete the preparation of the spray liquid.

[0059] (4) Preparation of coating:

[0060] The glass sheet was ultrasonically cleaned with anhydrous ethanol and deionized water for 10 minutes in turn to remove impurities, and then dried in a drying oven at 60°C for 10 minutes. Then, the spraying liquid prepared in step (3) was evenly sprayed on the glass sheet with a pressure of 0.4 MPa using a spray gun, with a spraying distance of 15 cm, and the spraying was completed. The coating sample was then placed in a muffle furnace at 100°C for heat treatment for 7 hours, and then the baking temperature was raised to 120°C for 2 hours, and finally raised to 240°C for 1 hour. After cooling to room temperature, the anti-wax oil coating was obtained. The contact angle pictures of the obtained coating with water (room temperature) and molten wax oil (70°C) are shown in the figure. Figure 6 As shown, the contact angle of water on the coating was measured to be 157.5°, and the contact angle of molten wax oil was 151.1°. Figure 7The data graph of the rolling angle of wax oil at different temperatures of the base coating shows that the rolling angle is greater than 16.7° at 30°C and is less than 10° at 40°C~80°C. The rolling angle decreases accordingly with increasing temperature, indicating that this coating has good anti-wax oil performance at high temperatures. Figure 8 These are optical photos of wax oil starting to roll off the base coating at different temperatures. At 30°C, the wax oil has solidified into a solid and has a strong adhesion to the base coating. At 40°C, the wax oil is at the wax precipitation point, wax crystals begin to precipitate, and the wax oil becomes viscous. At 50°C~80°C, it has excellent wax resistance. Figure 9 This is a diagram of the solidification-melting-rolling behavior of wax oil on the base coating. After the wax oil solidifies, the base coating is adjusted to 7°. When the base coating is heated to 60°C, the wax oil will roll off naturally.

[0061] For the polyvinylidene fluoride emulsion in step 3), after the coating is immersed in a 1M sodium hydroxide aqueous solution (pH=15) for 1 hour, the contact angle of the coating with polyvinylidene fluoride emulsion for water and oil is 155° after soaking for 1 hour. The contact angle of the coating without polyvinylidene fluoride emulsion for water and oil is generally 148°. The reason is that polyvinylidene fluoride emulsion, as a high molecular polymer, has film-forming properties and corrosion resistance. Adding it to the coating can not only increase the adhesion of the coating but also improve the corrosion resistance of the coating.

[0062] The above embodiments are merely preferred technical solutions of the present invention and should not be construed as limiting the present invention. The embodiments and features in the embodiments of this application may be arbitrarily combined with each other unless they conflict. The scope of protection of the present invention shall be the technical solutions described in the claims, including equivalent alternatives to the technical features of the technical solutions described in the claims. Equivalent alternatives and improvements within this scope are also within the scope of protection of the present invention.

Claims

1. A method for preparing a wax-resistant oil coating, characterized in that: The method comprises the following steps: 1) Preparation of high-temperature adhesive aluminum dihydrogen phosphate: Add water to phosphoric acid and stir evenly. Then add aluminum hydroxide particles and stir at high temperature to react to form a transparent viscous liquid. Finally, cool to room temperature to obtain the high-temperature adhesive aluminum dihydrogen phosphate. 2) Fluorination modification of nano-silica: Place nano-silica particles in a mixed solution of a fluorinated modifier and n-hexane, stir evenly, and allow the solution to evaporate naturally. Finally, wash with anhydrous ethanol and dry to obtain fluorinated nano-silica. 3) Preparation of the spraying liquid: Dissolve the high-temperature adhesive aluminum dihydrogen phosphate prepared in step 1) in water, and then magnetically stir the aqueous polyvinylidene fluoride emulsion to obtain solution A. Add the fluorinated nano-silica and polyimide powder prepared in step 2) to anhydrous ethanol in sequence, magnetically stir, and ultrasonically process to obtain solution B. Then, pour solution B into solution A to obtain solution C, magnetically stir, and ultrasonically process to complete the spraying liquid. 4) Preparation of the base coating: The nickel foam is cut into sheets, ultrasonically cleaned with anhydrous ethanol and deionized water to remove impurities, and then dried in a drying oven. The spray liquid prepared in step 3) is then evenly sprayed onto the nickel foam using a spray gun. After spraying and drying, the wax and oil resistant coating is obtained. In step 1), the molar ratio of aluminum hydroxide particles to phosphoric acid is 1:(3-3.2), the mass fraction of phosphoric acid is 85%, the high-temperature stirring temperature is 120-130°C, and the high-temperature stirring time is 20-30 minutes; High temperature stirring can be achieved by constant temperature magnetic stirring or oil bath stirring; In step 2), the fluorinated modifier is perfluorooctyltrichlorosilane, and the mass concentration of the mixed solution of perfluorooctyltrichlorosilane and n-hexane is 0.5% to 1%; In step 3), the solid-liquid ratio of high-temperature adhesive: water: polyvinylidene fluoride emulsion: fluorinated silica: polyimide: anhydrous ethanol is (1-2): (3-5): (2-3): (0.4-0.5): (0.2-0.4): (12-15) g / ml / g / g / g / ml; In step 3), the magnetic stirring time is 5-10 minutes, the stirring speed is 900-1000 r / min, the ultrasonic time is 3-5 minutes, the ultrasonic power is 75-80 W, and the ultrasonic frequency is 35-45 kHz. The magnetic stirring and ultrasonic conditions are set to the same conditions twice; In step 4), the spraying pressure of the spray gun is 0.4-0.5 MPa, and the spraying distance is 20-25 cm. The method of uniform spraying is to spray for 1 second, then blow with air from the spray gun for 5 seconds, and finally dry in a muffle furnace at 100°C for 5 seconds, and repeat the previous steps until the substrate is covered with a uniform coating. In step 4), the drying is first performed at a temperature of 100°C for 7 to 10 hours, followed by a baking temperature of 115-125°C for 1.5 to 2.5 hours, and finally a baking temperature of 230-250°C for 0.5 to 1.5 hours.

2. The method for preparing the wax-resistant oil coating according to claim 1, wherein: In the step 4), the specifications of the nickel foam are as follows: thickness 0.5 mm, pore diameter 0.1 mm, porosity 97.2%, and PPI 110.

3. The method for preparing the wax-resistant oil coating according to claim 1, wherein: In the step 4), the ultrasonic cleaning time of anhydrous ethanol and deionized water is 5-15 minutes, the ultrasonic power is 75-85W, the ultrasonic frequency is 35-45KHz, the drying temperature of the drying oven is 55-65°C, and the drying time is 10-30 minutes.

4. The method for preparing the wax-resistant oil coating according to claim 1, wherein: In step 4), the spraying pressure of the spray gun is 0.4-0.5 MPa, and the spraying distance is 20-25 cm. The uniform spraying method is to first spray for 1 second, then blow with the spray gun for 5 seconds, and finally dry in a muffle furnace at 100°C for 5 seconds, and repeat the previous steps until the substrate is covered with a uniform coating.

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