CN115572516B - A kind of water-soluble high polymer composite drag-reducing coating, coating preparation method and application - Google Patents

Abstract

The invention discloses a water-soluble polymer composite drag-reducing coating, coating preparation method and application, and belongs to the technical field of underwater drag-reducing coating; the coating includes components: polyvinylpyrrolidone, solvent, crosslinking agent, thickener, Polymer drag reducer and pigment; the steps of the coating preparation method are: adding polyvinylpyrrolidone into a solvent for physical stirring, adding a crosslinking agent to undergo a covalent bond graft compound reaction; then adding a thickener, a polymer drag reducer, The solvent is added to the ball mill tank together, and pigments are added, and the water-soluble polymer composite drag-reducing coating is obtained by physical grinding for 48 hours; layer. The present invention uses polyvinylpyrrolidone as a film-forming agent, and the prepared coating can be hydrolyzed, which facilitates the slow release of the polymer drag reducer; adding a cross-linking agent to obtain macromolecular polyvinylpyrrolidone improves the durability of the coating and the adhesion to the substrate, effectively Prolong the drag-reducing aging of the coating; both are environmentally friendly and harmless.

Description

A kind of water-soluble polymer composite drag-reducing coating, coating preparation method and application

technical field

The invention belongs to the technical field of underwater drag-reducing coatings, and in particular relates to a water-soluble high polymer composite drag-reducing coating, a coating preparation method and application.

Background technique

With the increasingly fierce competition in the ocean, countries around the world continue to strengthen the protection of ocean rights and interests and the degree of ocean development, so the comprehensive performance of wading vehicles needs to be further improved. The resistance encountered by underwater vehicles during navigation mainly includes frictional resistance, pressure difference resistance and wave resistance, of which frictional resistance accounts for the largest proportion. and other major engineering significance.

Drag-reducing coatings are applied on the surface of aircraft to achieve drag reduction, which is of great value in engineering applications. However, the drag-reducing coatings reported in the literature have shortcomings such as short timeliness, weak drag-reducing effect, and non-environmental protection. Invention patent CN104845467B introduces an "environmentally friendly anti-fouling and drag-reducing composite functional coating and its preparation method". The composition of the coating components is simply blending. During use, hydrophilic components such as polyacrylamide are easy to dissolve and fall off. , The drag reduction and antifouling time is short. Invention patent CN112646490A introduces "a salt-spray resistant flexible drag-reducing coating and its preparation method and application". The method is single, and the drag reduction rate is basically in the range of 0-2%, and the drag reduction rate is low. In addition, organic solvents such as ether alcohols and ketones are used as dispersants, which not only have a high cost, but also release a large amount of organic compounds during use, which is harmful to organisms and the environment.

Among the many methods of reducing frictional resistance, the effect of polymer drag reduction is remarkable. Based on this, when the polymer coating is soaked in the fluid or washed by the fluid, the coating slowly dissolves, and the polymer slowly releases into the flow field, changing the fluid turbulence structure, suppressing the generation of large-scale vortex structures, and achieving drag reduction Effect. Therefore, it is urgent to combine traditional underwater vehicle coating technology with polymer drag reduction to prepare water-soluble composite polymer drag reduction coatings.

Contents of the invention

Technical problem to be solved:

In order to avoid the deficiencies of the prior art, the present invention provides a water-soluble high polymer composite drag-reducing coating, coating preparation method and application. The coating prepared by using the water-soluble high polymer composite drag-reducing coating can reduce the The navigation resistance of the aircraft can be reduced, so as to realize the increase of navigation speed and save energy consumption.

The technical scheme of the present invention is: a water-soluble high polymer composite drag-reducing coating, characterized in that it includes polyvinylpyrrolidone, solvent, cross-linking agent, thickener, polymer drag-reducing agent, pigment; the mass of each component The ratio is: polyvinylpyrrolidone: solvent: crosslinking agent: thickener: polymer drag reducer: dye = 20:800:2:1:(50-100):0.4.

A further technical solution of the present invention is: the polyvinylpyrrolidone is a white solid particle with a molecular weight of 1,000,000-1,600,000 and a particle size of 105-170 μm.

A further technical solution of the present invention is: the solvent is absolute ethanol, which is a colorless, transparent and volatile liquid.

A further technical solution of the present invention is: the cross-linking agent is tannic acid, which is light yellow powder, soluble in absolute ethanol, and has a particle size of 125-170 μm.

A further technical solution of the present invention is: the thickener is bentonite, which is light gray powder with a particle size of 125-170 μm.

A further technical solution of the present invention is: the polymer drag reducer is one or more of polyacrylamide, guar gum, tragacanth gum, locust bean gum and Arabic gum, and the particle size is 125-170 μm.

A further technical solution of the present invention is: the pigment is Rhodamine B, which is a reddish-brown powder with a particle size of 125-170 μm.

A method for preparing a water-soluble polymer composite drag-reducing coating, characterized in that the specific steps are as follows:

Step 1: Put the solvent in the container and stir it with a stirrer; initially set the speed of the stirrer to 200r/min, and add the weighed polyvinylpyrrolidone into the solvent at a speed of 1-2g/s during the stirring process; After all the mixture is added, adjust the speed of the agitator to 90r/min; seal around the stirring shaft of the agitator with a sealing film, continue stirring for 3.5 hours, and physically mix to obtain a polyvinylpyrrolidone solution;

Step 2: Add the weighed cross-linking agent into the prepared polyvinylpyrrolidone solution, and continue to stir for 3 hours, so that the polyvinylpyrrolidone can fully undergo a covalent bond grafting compound reaction to obtain a macromolecular polyvinylpyrrolidone solution;

Step 3: Take the macromolecular polyvinylpyrrolidone solution prepared in step 2, add the thickener, polymer drag reducer, and solvent into the ball mill tank, add pigments, and physically grind for 48 hours to obtain a water-soluble polymer compound Drag-reducing coatings;

Step 4: Apply the uniformly ground water-soluble high polymer composite drag-reducing coating to the test plate with the boss according to the different ratios of the coating length and the length of the test plate, and cool it at room temperature for 6 hours. A water-soluble high polymer composite drag-reducing coating was obtained.

A further technical solution of the present invention is: in the step 1, before mixing, the polyvinylpyrrolidone, crosslinking agent, thickener, polymer drag reducer, and pigment are all physically ground to make the particle size reach 20-50 μm.

An application of a water-soluble polymer composite drag-reducing coating, characterized in that the water-soluble polymer composite coating is applied to the front end of the aircraft head by a brushing method, and the length of the coating accounts for the length of the drag-reducing area. 1/4-1/2 of that to reduce the sailing resistance of the aircraft.

Beneficial effect

The beneficial effects of the present invention are: the present invention uses polyvinylpyrrolidone as a film-forming agent, and the prepared coating can be hydrolyzed, which is convenient for the slow release of the polymer drag reducer; the present invention adds a cross-linking agent to obtain macromolecular polyvinylpyrrolidone, which improves The durability of the coating and the adhesion to the substrate can effectively prolong the drag-reducing aging of the coating; and the raw materials are cheap, and they are environmentally friendly and harmless.

The present invention uses absolute ethanol as a solvent, avoids the conventional method of dissolving the polymer drag reducer, utilizes the property that the polymer drag reducer is soluble in water and insoluble in absolute ethanol, and disperses the polymer drag reducer in the film-forming In the agent, the degradation of the polymer drag reducing agent is greatly reduced, and the drag reducing effect is durable and effective.

The coating of the present invention is painted according to different length ratios (such as 1/1, 3/4, etc., which are dimensionless parameters, and are the ratio of the brushing length to the length of the test plate). The surface of the coating is in contact with the fluid, and the polymer drag reducer is slowly released in the flow field. Due to the certain viscosity and roughness of the coating surface, the drag reduction effect of the slow-release drag reducer is not obvious in the test section, and the drag reduction occurs in the Downstream of the test section. The method of partial brushing is adopted to paint according to the proportion of different lengths, the coating area is shortened, and the area where the polymer drag reducer achieves the drag reduction effect is advanced, so that the test section can achieve the ideal drag reduction effect and save materials. When the proportion of brushing length is 1/2, the drag reduction rate can reach up to 8%, which is better than the drag reduction effect of all brushing.

Description of drawings

Fig. 1 schematic diagram of experimental process;

Figure 2 Drag reduction effect of coatings with different length ratios at different Reynolds numbers.

Detailed ways

The embodiments described below by referring to the figures are exemplary and are intended to explain the present invention and should not be construed as limiting the present invention.

A water-soluble polymer composite drag-reducing coating of the present invention includes polyvinylpyrrolidone, solvent, crosslinking agent, thickener, polymer drag-reducing agent, and pigment; the mass ratio of each component is: polyvinylpyrrolidone: solvent: cross-linking agent Joint agent: thickener: polymer drag reducer: dye=20:800:2:1:(50-100):0.4.

The polyvinylpyrrolidone is a non-ionic water-soluble polymer, which is a white solid particle with a molecular weight of 1,000,000-1,600,000 and a particle size of 105-170 μm. First pass the cross-linking agent to make it undergo covalent bond grafting compound reaction, then add the thickener to enhance the viscosity, adjust the proportion of the cross-linking agent, thickener and polymer drag reducer, and adjust the dissolution rate of the coating to Control the sustained release rate of polymer drag reducer.

Preferably, the solvent is absolute ethanol, which is a colorless, transparent and volatile liquid.

Preferably, the crosslinking agent is tannic acid, which is light yellow powder, dissolved in absolute ethanol, and has a particle size of 125-170 μm.

Preferably, the thickener is bentonite, which is a light gray powder with a particle size of 125-170 μm.

Preferably, the polymer drag reducer is one or more of polyacrylamide, guar gum, tragacanth gum, locust bean gum and Arabic gum, with a particle size of 125-170 μm.

Preferably, the pigment is Rhodamine B, which is a reddish-brown powder with a particle size of 125-170 μm.

The invention relates to a water-soluble high polymer composite coating, which is prepared by physical mixing and chemical compounding. The preparation method specifically adopts a ball milling method. All kinds of raw materials are physically ground to make the particle size reach 20-50μm before use.

Embodiment one:

Step 1: Use an electronic balance to weigh 50g of polyvinylpyrrolidone, and measure 1000mL of absolute ethanol in a beaker; place the beaker containing the solvent under a cantilever electric stirrer to stir, and the stirrer speed is set to 200r/min. During the stirring process Add the weighed polyvinylpyrrolidone into the beaker at a speed of 1-2g/s, and after all the addition, adjust the speed of the stirrer to 90r/min; seal the surrounding of the stirring shaft with a sealing film, and continue stirring for 3.5h. Mix to obtain polyvinylpyrrolidone solution;

Step 2: Weigh 5 g of tannic acid with an electronic balance and add it to the prepared polyvinylpyrrolidone solution, and continue to stir for 3 hours, so that the polyvinylpyrrolidone can fully undergo a covalent bond grafting compound reaction to obtain a macromolecular polyvinylpyrrolidone solution;

Step 3: Take 200mL of the solution prepared in step 2, weigh 0.5g of bentonite and 25g of polyacrylamide with an electronic balance, measure 200mL of absolute ethanol in a beaker, add them to a ball mill jar, add 0.2g of pigment, and physically grind for 48 hours , to prepare a water-soluble high polymer composite coating;

Step 4: Apply the uniformly ground water-soluble high polymer composite paint to the test plate with the boss according to the ratio of the coating length to the test plate length of 1/1 by brushing method, and cool it at room temperature for 6 hours. Water-soluble polymer composite coating.

Embodiment two:

Step 1: Use an electronic balance to weigh 50g of polyvinylpyrrolidone, and measure 1000mL of absolute ethanol in a beaker; place the beaker containing the solvent under a cantilever electric stirrer to stir, and the stirrer speed is set to 200r/min. During the stirring process Add the weighed polyvinylpyrrolidone into the beaker at a speed of 1-2g/s, and after all the addition, adjust the speed of the stirrer to 90r/min; seal the surrounding of the stirring shaft with a sealing film, and continue stirring for 3.5h. Mix to obtain polyvinylpyrrolidone solution;

Step 2: Weigh 5 g of tannic acid with an electronic balance and add it to the prepared polyvinylpyrrolidone solution, and continue to stir for 3 hours, so that the polyvinylpyrrolidone can fully undergo a covalent bond grafting compound reaction to obtain a macromolecular polyvinylpyrrolidone solution;

Step 3: Take 200mL of the solution prepared in step 2, weigh 0.5g of bentonite and 25g of polyacrylamide with an electronic balance, measure 200mL of absolute ethanol in a beaker, add them to a ball mill jar, add 0.2g of pigment, and physically grind for 48 hours , to prepare a water-soluble high polymer composite coating;

Step 4: Apply the uniformly ground water-soluble high polymer composite paint to the test plate with a boss according to the ratio of the coating length to the test plate length of 3/4 by brushing method, and cool at room temperature for 6 hours to prepare Water-soluble polymer composite coating.

Embodiment three:

Step 1: Use an electronic balance to weigh 50g of polyvinylpyrrolidone, and measure 1000mL of absolute ethanol in a beaker; place the beaker containing the solvent under a cantilever electric stirrer to stir, and the stirrer speed is set to 200r/min. During the stirring process Add the weighed polyvinylpyrrolidone into the beaker at a speed of 1-2g/s, and after all the addition, adjust the speed of the stirrer to 90r/min; seal the surrounding of the stirring shaft with a sealing film, and continue stirring for 3.5h. Mix to obtain polyvinylpyrrolidone solution;

Step 2: Weigh 5 g of tannic acid with an electronic balance and add it to the prepared polyvinylpyrrolidone solution, and continue to stir for 3 hours, so that the polyvinylpyrrolidone can fully undergo a covalent bond grafting compound reaction to obtain a macromolecular polyvinylpyrrolidone solution;

Step 3: Take 200mL of the solution prepared in step 2, weigh 0.5g of bentonite and 25g of polyacrylamide with an electronic balance, measure 200mL of absolute ethanol in a beaker, add them to a ball mill jar, add 0.2g of pigment, and physically grind for 48 hours , to prepare a water-soluble high polymer composite coating;

Step 4: Apply the uniformly ground water-soluble high polymer composite paint to the test plate with a boss according to the ratio of the coating length to the test plate length of 1/2 by brushing method, and cool at room temperature for 6 hours to prepare Water-soluble polymer composite coating.

Embodiment four:

Step 1: Use an electronic balance to weigh 50g of polyvinylpyrrolidone, and measure 1000mL of absolute ethanol in a beaker; place the beaker containing the solvent under a cantilever electric stirrer to stir, and the stirrer speed is set to 200r/min. During the stirring process Add the weighed polyvinylpyrrolidone into the beaker at a speed of 1-2g/s, and after all the addition, adjust the speed of the stirrer to 90r/min; seal the surrounding of the stirring shaft with a sealing film, and continue stirring for 3.5h. Mix to obtain polyvinylpyrrolidone solution;

Step 2: Weigh 5 g of tannic acid with an electronic balance and add it to the prepared polyvinylpyrrolidone solution, and continue to stir for 3 hours, so that the polyvinylpyrrolidone can fully undergo a covalent bond grafting compound reaction to obtain a macromolecular polyvinylpyrrolidone solution;

Step 3: Take 200mL of the solution prepared in step 2, weigh 0.5g of bentonite and 25g of polyacrylamide with an electronic balance, measure 200mL of absolute ethanol in a beaker, add them to a ball mill jar, add 0.2g of pigment, and physically grind for 48 hours , to prepare a water-soluble high polymer composite coating;

Step 4: Apply the uniformly ground water-soluble high polymer composite paint to the test plate with a boss according to the ratio of the coating length to the test plate length of 1/4 by brushing method, and cool at room temperature for 6 hours to prepare Water-soluble polymer composite coating.

Embodiment five:

Step 1: Use an electronic balance to weigh 50g of polyvinylpyrrolidone, and measure 1000mL of absolute ethanol in a beaker; place the beaker containing the solvent under a cantilever electric stirrer to stir, and the stirrer speed is set to 200r/min. During the stirring process Add the weighed polyvinylpyrrolidone into the beaker at a speed of 1-2g/s, and after all the addition, adjust the speed of the stirrer to 90r/min; seal the surrounding of the stirring shaft with a sealing film, and continue stirring for 3.5h. Mix to obtain polyvinylpyrrolidone solution;

Step 2: Weigh 5 g of tannic acid with an electronic balance and add it to the prepared polyvinylpyrrolidone solution, and continue to stir for 3 hours, so that the polyvinylpyrrolidone can fully undergo a covalent bond grafting compound reaction to obtain a macromolecular polyvinylpyrrolidone solution;

Step 3: Take 200mL of the solution prepared in step 2, weigh 0.5g of bentonite and 25g of polyacrylamide with an electronic balance, measure 200mL of absolute ethanol in a beaker, add them to a ball mill jar, add 0.2g of pigment, and physically grind for 48 hours , to prepare a water-soluble high polymer composite coating;

Step 4: Apply the uniformly ground water-soluble high polymer composite paint to the test plate with a boss according to the ratio of the coating length to the test plate length of 1/8 by brushing method, and cool at room temperature for 6 hours to prepare Water-soluble polymer composite coating.

The drag reduction rate of Embodiment 1 can reach up to 2%, the drag reduction rate of Embodiment 2 and 5 can reach up to 4.5%, and the drag reduction rate of Embodiment 3 and 4 can reach up to 8%. Using the method of partial brushing, brushing according to the proportion of different lengths, the coating area is shortened, and the area where the polymer drag reducer achieves the drag reduction effect is advanced, so that the ideal drag reduction effect is achieved in the test section. The Reynolds number of the coating with different length ratios for the best drag reduction effect is different. Under different Reynolds numbers, an appropriate length ratio is required to achieve the best drag reduction effect.

Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be construed as limitations to the present invention. Variations, modifications, substitutions, and modifications to the above-described embodiments are possible within the scope of the present invention.

Claims (7)

1. A water-soluble polymer composite drag-reducing coating, characterized in that: comprising polyvinylpyrrolidone, solvent, crosslinking agent, thickener, polymer drag-reducing agent, pigment; each component mass ratio is: polyethylene Pyrrolidone: solvent: crosslinking agent: thickener: polymer drag reducer: pigment=20:800:2:1:(50-100):0.4; Described solvent is dehydrated alcohol, is colorless transparent volatile liquid; The crosslinking agent is tannic acid, which is light yellow powder, soluble in absolute ethanol, and has a particle size of 125-170 μm; The polymer drag reducer is one or more of polyacrylamide, guar gum, tragacanth gum, locust bean gum and Arabic gum, and the particle size is 125-170 μm. 2. A water-soluble polymer composite drag-reducing coating according to claim 1, characterized in that: the polyvinylpyrrolidone is a white solid particle with a molecular weight of 1,000,000-1,600,000 and a particle size of 105-170 μm. 3. A water-soluble high polymer composite drag-reducing coating according to claim 1, characterized in that: the thickener is bentonite, which is light gray powder with a particle size of 125-170 μm. 4. A water-soluble polymer composite drag-reducing coating according to claim 1, characterized in that: the pigment is rhodamine B, which is a reddish-brown powder with a particle size of 125-170 μm. 5. a method adopting any one of claim 1-4 water-soluble polymer composite drag-reducing coating to prepare water-soluble polymer composite drag-reducing coating, is characterized in that concrete steps are as follows: Step 1: Put the solvent in the container and stir it with a stirrer; initially set the speed of the stirrer to 200r/min, and add the weighed polyvinylpyrrolidone into the solvent at a speed of 1-2g/s during the stirring process; After all the mixture is added, adjust the speed of the agitator to 90r/min; seal around the stirring shaft of the agitator with a sealing film, continue stirring for 3.5 hours, and physically mix to obtain a polyvinylpyrrolidone solution; Step 2: Add the weighed cross-linking agent into the prepared polyvinylpyrrolidone solution, and continue to stir for 3 hours, so that the polyvinylpyrrolidone can fully undergo a covalent bond grafting compound reaction to obtain a macromolecular polyvinylpyrrolidone solution; Step 3: Take the macromolecular polyvinylpyrrolidone solution prepared in step 2, add the thickener, polymer drag reducer, and solvent into the ball mill tank, add pigments, and physically grind for 48 hours to obtain a water-soluble polymer compound Drag-reducing coatings; Step 4: Apply the uniformly ground water-soluble high polymer composite paint to the test plate with the boss according to the different ratios of the coating length and the length of the test plate by brushing, and cool at room temperature for 6 hours to obtain a water-soluble polymer coating. High polymer composite drag reducing coating. 6. The method for preparing a water-soluble polymer composite drag-reducing coating according to claim 5 is characterized in that: in the step 1, before mixing, polyvinylpyrrolidone, crosslinking agent, thickener, high Molecular drag reducers and pigments are all physically ground to achieve a particle size of 20-50 μm. 7. An application of a water-soluble high polymer composite drag-reducing coating prepared by adopting any one of claims 1-4, wherein the water-soluble high polymer The compound coating is brushed on the front end of the aircraft head by brushing, and the length of the coating accounts for 1/4-1/2 of the length of the drag reduction area to reduce the navigation resistance of the aircraft.

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