Coating method of anti-icing coating for layer-by-layer assembled wind power blade

Abstract

The invention relates to the technical field of coating of blade coatings, in particular to a coating method of an anti-icing coating for a layer-by-layer assembled wind power blade. A coating method of the anti-icing coating for the layer-by-layer assembled wind power blade comprises the steps that S100, the graphene layer is settled on the bottom layer; s200, graphene and a two-component polyurethane coating are mixed into black suspension liquid, and the surface of the blade is coated with the brown suspension liquid; s300, two-component polyurethane containing SiO2 nano particles and black dye is settled on the graphene layer after curing; s400, the step S200 and the step S300 are repeated for multiple times; and S500, performing air drying to form a plurality of layers of coatings containing dyes and nano-particles. The coating method of the anti-icing coating for the layer-by-layer assembled wind power blade has the advantages that a hydrophobic surface and heating have a synergistic effect, water drops are difficult to wet the surface of the wind power blade, meanwhile, microcosmically condensed water drops can be evaporated and removed in time, the surface is maintained not to be damaged in an extremely wet and cold environment, and a long-acting anti-frost effect is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of blade coating, and in particular to a method for coating an anti-icing coating for a wind turbine blade assembled layer by layer. Background Art

[0002] China has many high mountains, grasslands and deserts, which are very suitable for wind power generation. However, in cold seasons, wind turbine blades are frequently covered with frost, especially in areas with high humidity such as Yunnan and Guizhou. Frost on the blades will damage the surface structure, increase the weight of the blades, affect the aerodynamic efficiency, reduce the service life, and in severe cases may lead to the consequences of blade breakage.

[0003] In order to solve the problem of blade frosting, a variety of measures have been taken in the field of blade coating research. For example, the Chinese invention patent with publication number CN102120913A discloses a water-based polyurethane coating for wind turbine blade coating protection. The primer and topcoat are composed of a two-component primer with a water-based hydroxy acrylic dispersion A145 as a base resin and a water-dispersible isocyanate 304 plus propylene glycol methyl ether acetate as a curing agent; the two-component topcoat with a water-based hydroxy acrylic dispersion A145 as a base resin and a water-dispersible isocyanate XP2547 as a curing agent, and the material equivalent ratio of component B is 1.5. The coating of this patent can play an anti-frosting role to a certain extent. However, only coatings cannot completely solve the frosting problem. In areas with high humidity and serious frosting problems, there are still varying degrees of frosting problems. Summary of the invention

[0004] In view of this, the present invention aims to provide a method for coating an anti-icing coating for wind turbine blades assembled layer by layer. The coating is coated on the surface of the blade by layer-by-layer assembly (LBL). The bottom layer uses polyurethane doped with graphene as a heating layer, and the surface uses polyurethane doped with silica nanoparticles and black dyes for multiple precipitation. The cross-linking reaction after the two-component polyurethane is mixed firmly fixes the nanoparticles. The addition of silica nanoparticles is to create a micro-nano structure on the surface of the blade. Due to the existence of the roughness, the water droplets and the blade surface form a gas isolation layer. In this mode, the contact angle of the water droplet is obtained by the weighted summation of the contact angles of the concave and convex parts of the surface microstructure. The contact angle of the droplet becomes larger, showing a hydrophobic effect. Under sufficient light conditions, the blade surface area increased by the micro-nano gullies and the black coating can effectively absorb sunlight, promote the evaporation of micro-droplets from the blade surface through the photothermal conversion effect, and save electricity without an external heat source; at night or in poor light conditions, the graphene layer can be electrically heated to achieve the effect of removing micro-droplets. At the same time, because the nanoparticles are deposited on the blade base by assembling layer by layer, during the operation of the blade, even if the surface nanoparticles are worn by wind or rain erosion, the internal particles will be exposed and continue to function. The number of LBL depositions can also regulate the service life of the coating. The coating method proposed by the present invention is simple to operate and is suitable for extremely wet and cold wind farm environments.

[0005] In order to solve the above problems, the present invention provides a method for coating an anti-icing coating for a wind turbine blade assembled layer by layer, comprising:

[0006] S100, bottom sedimentation graphene layer;

[0007] S200, mixing graphene and two-component polyurethane coating into a black suspension, and applying the brown suspension on the surface of the blade;

[0008] S300, depositing a two-component polyurethane containing SiO2 nanoparticles and a black dye on the graphene layer after curing;

[0009] S400, repeating steps S200 and S300 multiple times;

[0010] S500, forming a multi-layer coating containing dyes and nanoparticles by natural air drying or heated air drying.

[0011] Furthermore, the amount of graphene added in the graphene layer is 3%-5%.

[0012] Further, in step S200, the graphene and the two-component polyurethane coating are mixed by ultrasonic dispersion;

[0013] The coating was applied on the blade surface within 2 minutes after the ultrasonic dispersion was completed.

[0014] Furthermore, the black fuel is carbon black, aniline black or manganese iron black.

[0015] Furthermore, the amount of black dye added is 0.5%-1%.

[0016] Furthermore, the particle size of SiO2 is 10-100 nm.

[0017] Furthermore, the added amount of SiO2 nanoparticles is 1%-3%.

[0018] Furthermore, in step S300, 0.1% of sodium tripolyphosphate, sodium hexametaphosphate or sodium pyrophosphate inorganic dispersant is added to the coating together with the SiO2 nanoparticles.

[0019] Further, in step S400, the number of repetitions is 3-5 times.

[0020] Furthermore, in step S400, after the outermost layer is coated, the coating is heated to a temperature above the glass transition temperature of the coating and maintained for 2 hours.

[0021] Compared with the prior art, the anti-icing coating coating method for wind turbine blades assembled layer by layer according to the present invention has the following advantages:

[0022] The advantage of this technical solution is that it utilizes multi-factor synergy. The first is that the doped nanoparticles form a micro-nano surface controlled by the Cassie-Baxter model, which produces hydrophobicity. The second is that heating promotes droplet evaporation. When there is sufficient light, the black appearance of the blade after adding graphene and dye and the increased blade surface area due to the microscopic concave-convex structure together improve the light-to-heat conversion rate of the wind turbine blade, replace artificial heat sources, and save costs; in the case of insufficient light, the graphene layer can also be used for electrical heating. The hydrophobic surface and heating work together, and it is difficult for water droplets to wet the surface of the wind turbine blade. At the same time, the condensed water droplets at the microscopic level can be evaporated and removed in time, maintaining the surface from being damaged in an extremely wet and cold environment. Because the hydrophobicity of the coating comes from the micro-nano structure of the surface, the multilayer structure prepared by LBL can make the coating surface even if it is worn, and the exposure of the internal nanoparticles can continue to maintain the rough surface of the micro-nano, achieving a long-lasting anti-frost effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 A schematic diagram of an anti-icing coating structure according to an embodiment of the present invention;

[0024] Figure 2 It is a schematic diagram of the structure of the anti-icing coating after surface wear according to an embodiment of the present invention.

[0025] Description of reference numerals:

[0026] 1-SiO2, 2-micro-nanostructured surface, 3-water droplet, 4-graphene layer, 5-polyurethane layer, 6-worn surface, 7-light irradiation. DETAILED DESCRIPTION

[0027] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0028] In the present invention, the descriptions involving "first", "second", "upper", "lower", etc. are only used for descriptive purposes and cannot be understood as indicating or suggesting their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first", "second", "upper", "lower" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in the field to implement. When the technical solutions between the embodiments can be combined, they are all within the protection scope required by the present invention.

[0029] The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments.

[0030] like Figure 1 As shown, a method for coating wind turbine blades with an anti-icing coating assembled layer by layer comprises:

[0031] S100, bottom sedimentation graphene layer, graphene addition amount is 3%-5%;

[0032] S200, mixing graphene and two-component polyurethane coating into a black suspension, applying the brown suspension on the surface of the blade, mixing the graphene and the two-component polyurethane coating by ultrasonic dispersion, and applying the coating on the surface of the blade within 2 minutes after the ultrasonic dispersion is completed;

[0033] S300, depositing a two-component polyurethane containing SiO2 nanoparticles and a black dye on the graphene layer after curing;

[0034] Black fuel uses carbon black, aniline black or ferromanganese black, and the amount of black dye added is 0.5%-1%;

[0035] The particle size of SiO2 is 10-100nm, the addition amount of SiO2 nanoparticles is 1%-3%, and 0.1% of sodium tripolyphosphate, sodium hexametaphosphate or sodium pyrophosphate inorganic dispersant is added to the coating together with the SiO2 nanoparticles;

[0036] S400, repeating steps S200 and S300 multiple times, preferably 3-5 times;

[0037] After the outermost layer is coated, it is heated to above the glass transition temperature of the coating and maintained for 2 hours.

[0038] S500, forming a multi-layer coating containing dyes and nanoparticles by natural air drying or heated air drying.

[0039] The coating method of the present invention is specifically described based on a two-component waterborne polyurethane coating commonly used in the wind turbine blade industry.

[0040] Embodiment 1

[0041] First, mechanically mix according to the fixed ratio of the topcoat, add 5% pure water to dilute, then add 5% graphene, and after ultrasonic dispersion for 2 minutes, at a relative humidity of 25%-75%, a temperature of 15°C, maintain the temperature of the wind turbine blade base above 3°C, and use a roller to quickly and evenly roll it on the base surface, control the thickness to 70±20 microns, and solidify it after air drying or heating to form a graphene-doped conductive layer 4. After the conductive layer is settled, multi-level hydrophobic layer sedimentation is carried out: 1% SiO2 nanoparticles 1 are added, and 0.1% sodium tripolyphosphate dispersion stabilizer is added. After mechanical mixing is completed, use an ultrasonic disperser to ultrasonically disperse the mixed coating for 2 minutes. After ultrasonic dispersion is completed, use a roller to quickly and evenly roll it on the upper sedimentation layer. After solidification, repeat the above operation once to control the total thickness to 300±20 microns.

[0042] Embodiment 2

[0043] First, mechanically mix according to the fixed ratio of the topcoat, add 5% pure water to dilute, then add 5% graphene, and after ultrasonic dispersion for 2 minutes, at a relative humidity of 25%-75%, a temperature of 30°C, maintain the temperature of the wind turbine blade base above 3°C, and use a roller to quickly and evenly roll it on the base surface, control the thickness to 70±20 microns, and air-dry or heat it to solidify to form a graphene-doped conductive layer 4. After the conductive layer is settled, multi-level hydrophobic layer sedimentation is carried out: 3% SiO2 nanoparticles 1 are added, and 0.1% sodium tripolyphosphate dispersion stabilizer is added. After mechanical mixing is completed, use an ultrasonic disperser to ultrasonically disperse the mixed coating for 2 minutes. After ultrasonic dispersion is completed, use a roller to quickly and evenly roll it on the upper sedimentation layer. After solidification, repeat the above operation three times to control the total thickness to 300±20 microns.

[0044] When the blades with the coating are running in the wind field, the wetting behavior of water droplets on the blade surface follows the Cassie-Baxter model. The surface 2 with the micro-nano structure will form water droplets 3 with a large contact angle. The blade surface shows hydrophobicity. As the blade rotates, the water droplets are thrown out of the blade. At the same time, due to the addition of graphene and dye, the blade has a black outer surface. Under the condition of sunlight 7, the large surface area brought by the 2 structure will absorb light and convert it into heat. In the absence of light, it can also be heated by the graphene conductive layer. The microscopic droplets are heated and evaporated, inducing the droplets to merge and "bounce" off the blade surface, thereby preventing the formation of microscopic ice crystals and protecting the surface micro-nano structure 2 from being covered by ice crystals. During the operation of the blade, it has a large linear speed and is often subject to relatively severe wind erosion or rain erosion. The surface of the blade is easily worn. The hydrophobic layer of the coating is assembled by multiple depositions of polyurethane doped with nanoparticles. Even after the outer surface is worn, the internal nanoparticles can be exposed. The worn surface 6 still has a considerable micro-nano rough structure. The wetting model of water droplets on this surface is always controlled by the CB model. The blades can maintain good anti-frost effect even when used for a long time in extremely wet and cold environments.

[0045] Through the above two embodiments, different amounts of SiO2 added and heating temperatures, as well as the number of layers coated, are controlled respectively. The test results prove that by controlling the above parameters, multivariate synergy is utilized. The first is that the doped nanoparticles form a micro-nano surface controlled by the Cassie-Baxter model, producing hydrophobicity. The second is that heating promotes droplet evaporation: under sufficient light conditions, the black appearance of the blade after adding graphene and dyes and the increased blade surface area due to the microscopic concave-convex structure together improve the light-to-heat conversion rate of the wind turbine blade, replace artificial heat sources, and save costs; in the case of insufficient light, the graphene layer can also be used for electrical heating. The hydrophobic surface and heating work together, and it is difficult for water droplets to wet the surface of the wind turbine blade. At the same time, the condensed water droplets on the microscopic level can also be evaporated and removed in time, maintaining the surface in an extremely wet and cold environment without being damaged. Because the hydrophobicity of the coating comes from the micro-nano structure of the surface, the multilayer structure prepared by LBL can make the coating surface even if it is worn, and the exposure of the internal nanoparticles can continue to maintain the rough surface of the micro-nano surface, achieving a long-lasting anti-frost effect.

[0046] Although the present invention is disclosed as above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the scope defined by the claims.

Claims

1. A method for coating wind turbine blades with an anti-icing coating assembled layer by layer, characterized in that: include: S100, bottom sedimentation graphene layer; S200, mixing graphene and two-component polyurethane coating into a black suspension, and applying the brown suspension on the surface of the blade; S300, depositing a two-component polyurethane containing SiO2 nanoparticles and a black dye on the graphene layer after curing; S400, repeating steps S200 and S300 multiple times; S500, forming a multi-layer coating containing dyes and nanoparticles by natural air drying or heated air drying.

2. The method for coating an anti-icing coating for wind turbine blades assembled layer by layer according to claim 1, characterized in that: The graphene addition amount in the graphene layer is 3%-5%.

3. The method for coating an anti-icing coating for wind turbine blades assembled layer by layer according to claim 1, characterized in that: In step S200, graphene and a two-component polyurethane coating are mixed by ultrasonic dispersion; The coating was applied on the blade surface within 2 minutes after the ultrasonic dispersion was completed.

4. The method for coating an anti-icing coating for a wind turbine blade assembled layer by layer according to claim 1, characterized in that: Black fuels are carbon black, aniline black or manganese iron black.

5. The method for coating an anti-icing coating for wind turbine blades assembled layer by layer according to claim 4, characterized in that: The amount of black dye added is 0.5%-1%.

6. The method for coating an anti-icing coating for wind turbine blades assembled layer by layer according to claim 5, characterized in that: The particle size of SiO2 is 10-100nm.

7. The method for coating an anti-icing coating for wind turbine blades assembled layer by layer according to claim 6, characterized in that: The added amount of SiO2 nanoparticles is 1%-3%.

8. The method for coating an anti-icing coating for wind turbine blades assembled layer by layer according to claim 7, characterized in that: In step S300, 0.1% of sodium tripolyphosphate, sodium hexametaphosphate or sodium pyrophosphate inorganic dispersant is added to the coating together with the SiO2 nanoparticles.

9. The method for coating an anti-icing coating for a wind turbine blade assembled layer by layer according to claim 1, characterized in that: In step S400, the number of repetitions is 3-5 times.

10. The method for coating an anti-icing coating for a wind turbine blade assembled layer by layer according to claim 9, characterized in that: In step S400, after the outermost layer is coated, the coating is heated to a temperature above the glass transition temperature of the coating and maintained for 2 hours.

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