A thermal storage coating for wind turbine blades and a method of making the same

Abstract

The application discloses a heat storage coating for a wind power blade and a preparation method thereof, and belongs to the technical field of wind power blade coating. The coating takes a water-based polyaspartic ester polyurea base resin as a main body structure, disperses and fixes a hydrated salt phase change material in the water-based polyaspartic ester polyurea base resin through an adhesive, and the hydrated salt phase change material exists in the form of heat storage microcapsules, wherein the main body of the capsule is granular expanded graphite, the pores of the expanded graphite are filled with the hydrated salt phase change material, and the hydrated salt phase change material undergoes a phase change following an external environment and synchronously absorbs or releases heat. The coating has excellent heat absorption and storage performance because the hydrated salt is used as the phase change material, can effectively absorb and store light and heat into the coating, avoids daytime strong light from burning the blade, can prevent the wind power blade from icing at night when the temperature decreases, thereby more effectively protecting the blade from damage and improving the safety of the wind power generator.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of wind power blade coating, and particularly relates to a heat storage coating for a wind power blade and a preparation method thereof. BACKGROUND

[0002] Wind power generation is a clean and renewable energy, and the core equipment thereof is a wind turbine. The wind turbine mainly comprises a tower, a blade, a generator, a control system and the like. The blade is one of the most critical components of the wind turbine, and the design and material selection thereof directly affect the performance and service life of the wind turbine.

[0003] However, the wind turbine is usually located in an easily frozen area with large diurnal temperature difference, such as a high mountain or a border area. In these areas, the temperature is relatively high during the day with sufficient sunlight, but the temperature drops below zero at night, so the surface of the blade of the wind turbine is prone to icing. Once icing occurs on the surface of the blade, not only the aerodynamic performance of the blade is affected and the power generation efficiency of the wind turbine is reduced, but also about 20% to 50% of the power generation capacity is lost in a severe icing area, and the service life of the blade is also affected, which brings adverse effects on the operation of the wind turbine and personnel. SUMMARY

[0004] The purpose of the present application is to overcome the shortcomings of the prior art, and to provide a heat storage coating for a wind power blade and a preparation method thereof, so as to solve the problem of easy icing of the wind power blade in the prior art.

[0005] To achieve the above-mentioned purpose, the following technical solutions are adopted in the present application:

[0006] A heat storage coating for a wind power blade, by mass fraction, comprising 40% to 50% of a water-based polyaspartic ester polyurea base resin, 20% to 30% of a bonding agent and 20% to 40% of heat storage microcapsules; the bonding agent is a PTFE water-based emulsion; the heat storage microcapsules are dispersed in the water-based polyaspartic ester polyurea base resin.

[0007] The heat storage microcapsules are composed of expanded graphite and a hydrated salt phase change material, the hydrated salt phase change material is filled in the pores of the expanded graphite, and the hydrated salt phase change material is composed of di-potassium hydrogen phosphate hexahydrate, glycine and di-sodium hydrogen phosphate dodecahydrate.

[0008] The water-based polyaspartic ester polyurea base resin is composed of a heat storage polyaspartic ester dispersion and a water-based isocyanate, and the heat storage polyaspartic ester dispersion is composed of a polyether amine, a polyaspartic ester and a diisocyanate.

[0009] Further improvements of the present application are as follows:

[0010] Preferably, in the heat storage microcapsule, the mass fraction of expanded graphite is 5% to 15%, and the remainder is hydrated salt phase change material.

[0011] Preferably, the mass ratio of dipotassium hydrogen phosphate hexahydrate, glycine, and disodium hydrogen phosphate dodecahydrate is 176.67:13.86:0.99.

[0012] Preferably, the expanded graphite is any one or more of EG600, EG700 or EG800; the size of the expanded graphite raw material is ≤13um.

[0013] Preferably, in the heat storage polyaspartic acid ester dispersion, the mass ratio of polyaspartic acid ester to polyetheramine is (3-8):1, and the molar ratio of polyetheramine to diisocyanate is 1:(1-1.3).

[0014] A method for preparing a thermal storage coating for wind turbine blades includes the following steps:

[0015] Step 1: Add the hydrated salt phase change material to the expanded graphite and stir until homogeneous to obtain a heat storage microcapsule suspension;

[0016] Step 2: Add PTFE emulsion dropwise to the mixture of polyetheramine and polyaspartic acid ester, and stir evenly after addition to obtain process mixture one;

[0017] Step 3: Add heat storage microcapsule suspension dropwise to process mixture one, stir evenly to obtain process mixture two;

[0018] Step 4: Add diisocyanate dropwise to process mixture two to obtain process mixture three;

[0019] Step 5: Add water dropwise to process mixture three, stir evenly to obtain a mixture of thermal storage polyaspartic acid ester dispersion, PTFE emulsion and thermal storage microcapsules;

[0020] Step 6: Add the aqueous isocyanate to the mixture obtained in step 5, stir evenly, and then obtain the heat storage coating.

[0021] Preferably, in step 1, the preparation process of the hydrated salt phase change material is as follows: dipotassium hydrogen phosphate hydrate, glycine and disodium hydrogen phosphate dodecahydrate are mixed in a mass ratio of 176.67:13.86:0.99, placed in a water bath at 55°C and heated and stirred until melted into a transparent liquid to obtain the hydrated salt phase change material.

[0022] Preferably, in step 2, the PTFE emulsion is added over a period of 1 to 2 hours and the stirring rate is 40 to 70 r / min.

[0023] Preferably, in step 3, the dripping time of the heat storage microcapsule suspension is 1-2 hours, and the stirring rate is 50-60 r / min.

[0024] Preferably, in step 5, the water is added over a period of 0.5 to 1 hour, the stirring speed after addition is 1000 to 1300 r / min, and the stirring time after addition is 0.3 to 0.5 hours.

[0025] Preferably, in step 6, the amount of aqueous isocyanate added is determined by the mass of the polyaspartic ester dispersion, and the molar ratio of -NH in the polyaspartic ester dispersion to -NCO in the aqueous isocyanate is 1.2:1.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] This invention discloses a thermal storage coating for wind turbine blades. The coating uses polyaspartic acid ester polyurea-based resin as its main structure. An inorganic filler—hydrated salt phase change material—is dispersed in the polyaspartic acid ester polyurea-based resin via a binder. The hydrated salt phase change material exists in the form of thermal storage microcapsules, where the main body of the capsules is granular expanded graphite with a loose, porous, worm-like structure. The pores within the expanded graphite are filled with the hydrated salt phase change material, which is fixed within the pores and undergoes a phase change in response to the external environment, simultaneously absorbing or releasing heat. This material selects hydrated salt as the phase change component because it has advantages such as high phase change enthalpy, high energy storage density, high thermal conductivity, and low cost. This improves the thermal storage performance of the coating and more effectively absorbs and stores daytime solar heat within the coating, preventing wind turbine blade icing and damage caused by nighttime temperature drops. On the other hand, polyurethane itself is a phase change material that can undergo a solid-solid phase change. It can also serve as a support material for other phase change materials, not only eliminating leakage problems but also reducing the cost of forming high-density composite phase change energy storage materials. Simultaneously, the selection of this material should consider its impact on blade performance and weight to ensure that it does not affect blade performance and weight, thereby improving the efficiency of the wind turbine. Expanded graphite is used as a thermal conductor and support material. Its loose structure, large specific surface area, and strong adsorption capacity allow the phase change components to be uniformly adsorbed within the pores of expanded graphite under the capillary action and surface tension, resulting in a tight interface between the two phases and no leakage during the phase change process. Its melting or decomposition temperature must be higher than the phase change temperature of the phase change components to ensure the shape stability and processability of the phase change components, thereby improving the adhesion and reliability of the coating and maintaining good heat absorption and release effects even in harsh environments. The problem of overcooling in the thermal storage coating is solved by adding nucleating agents and using stirring methods; the addition of separation inhibitors ensures the stability of the thermal storage coating composition and prevents phase separation. This material optimizes the formulation of thermal storage coatings to reduce manufacturing costs. This is achieved by selecting lower-priced raw materials, simplifying the production process, and improving production efficiency. Simultaneously, by enhancing the safety and reliability of wind turbine units, it can indirectly improve the economic benefits of wind power generation.

[0028] By using the material, the heat from daytime sunlight can be effectively utilized. When the sunlight is strong, it is absorbed and stored in the blade coating to ensure that the wind turbine blades are not scorched. When the temperature drops at night, the coating can release the heat to ensure that the surface of the wind turbine blades does not freeze when the temperature is low at night. Attached Figure Description

[0029] Figure 1 This is a flowchart of the method for preparing the thermal storage coating of the present invention. Detailed Implementation

[0030] The present invention will now be described in further detail with reference to the accompanying drawings:

[0031] To enable those skilled in the art to understand the features and effects of the present invention, the terms and expressions used in the specification and claims are explained and defined in general below. Unless otherwise specified, all technical and scientific terms used herein have the ordinary meaning understood by those skilled in the art regarding the present invention, and in case of conflict, the definitions in this specification shall prevail.

[0032] In this article, unless otherwise specified, “contains,” “includes,” “containing,” “has,” or similar terms cover the meanings of “composed of” and “mainly composed of,” for example, “A contains a” covers the meanings of “A contains a and others” and “A contains only a.”

[0033] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0034] The following examples use instruments and equipment conventional in the art. Experimental methods in the following examples, unless otherwise specified, are generally performed under conventional conditions or as recommended by the manufacturer. All raw materials used in the following examples are conventional commercially available products with specifications conventional in the art. In this specification and the following examples, unless otherwise specified, "%" refers to weight percentage, "parts" refers to parts by weight, and "ratio" refers to weight proportion.

[0035] The first aspect of this invention discloses a thermal storage coating for wind turbine blades. The coating comprises an aqueous polyaspartic acid ester polyurea-based resin, a binder, and thermal storage microcapsules, with mass fractions of 40%–50%, 20%–30%, and 20%–40%, respectively. The binder is an aqueous PTFE emulsion with a solid content of 90%. The thermal storage microcapsules are composed of expanded graphite and a hydrated salt phase change material, with the hydrated salt phase change material adsorbed within the pores of the expanded graphite. The hydrated salt phase change material is composed of dipotassium hydrogen phosphate hexahydrate, disodium hydrogen phosphate dodecahydrate, and glycine.

[0036] In the aforementioned disclosed thermal storage coating, waterborne polyaspartic acid ester polyurea base resin serves as the matrix material for wind turbine blade coatings. The binder can uniformly bond and fix the inorganic phase change filler in the matrix material of the coating, improving the dispersibility of the entire phase change filler. The phase change filler is composed of expanded graphite and hydrated salt phase change material. Expanded graphite has a loose and porous worm-like structure, while hydrated salt phase change material is used to store external heat or release heat according to its own morphological changes.

[0037] The thermal storage microcapsules utilize dipotassium hydrogen phosphate hexahydrate as the phase change matrix, disodium hydrogen phosphate dodecahydrate as a nucleating agent to facilitate the nucleation of dipotassium hydrogen phosphate hexahydrate in expanded graphite, glycine as a phase change separation inhibitor, and expanded graphite as a thermal conductor and supporting material. The coating is composed of water-based polyaspartic acid ester polyurea resin. A eutectic hydrated salt is prepared by combining dipotassium hydrogen phosphate hexahydrate, disodium hydrogen phosphate dodecahydrate, and glycine. This eutectic hydrated salt is adsorbed into expanded graphite to form a phase change filler. This phase change filler is then cross-linked with the water-based polyaspartic acid ester polyurea resin using a binder to form the thermal storage coating.

[0038] Among the aforementioned substances, binary or multi-component systems exist in stable or metastable equilibrium between two phases with different compositions within a certain temperature and composition range, exhibiting immiscibility. Glycine can prevent this phenomenon, ensuring that the multi-component system remains in the same stable phase state with uniform texture.

[0039] The waterborne polyaspartic ester polyurea-based resin is composed of a heat-storing polyaspartic ester dispersion and a waterborne isocyanate. The heat-storing polyaspartic ester dispersion is composed of polyetheramine, polyaspartic ester, and diisocyanate.

[0040] Specifically, the diisocyanate is any one or a mixture of isoflurone diisocyanate, hexamethylene diisocyanate, and 4,4'-dicyclohexylmethane diisocyanate.

[0041] Specifically, the polyetheramine is any one or a mixture of polyetheramine M230, polyetheramine M1000, or polyetheramine 2000.

[0042] Specifically, the polyaspartic ester is a mixture of F420 and F520, and the molar ratio of polyaspartic ester F420 to polyaspartic ester F520 is (4-5):1.

[0043] Specifically, the molar ratio of polyetheramine to diisocyanate is 1:(1 to 1.3).

[0044] Specifically, the mass ratio of polyaspartic acid ester to polyetheramine is (3-8):1.

[0045] The molar ratio of -NH in the thermal storage polyaspartic acid ester dispersion to -NCO in the aqueous isocyanate is 1:1.2.

[0046] The aforementioned coating, containing hydrated salts as a phase change material, exhibits excellent heat absorption and storage properties. It effectively absorbs and stores solar heat within the coating, preventing blade scorching from strong daytime sunlight and preventing icing of wind turbine blades at night when temperatures drop. This provides more effective protection against blade damage and improves the safety of the wind turbine. The coating is uniform and stable, resistant to supercooling and phase separation / immiscibility issues, and does not increase blade weight, thus not affecting wind turbine efficiency. Furthermore, the specific material selection makes the coating lighter, making it more suitable for wind turbine blades. The coating's preparation process is simple, resulting in lower heat storage costs. In areas with large diurnal temperature variations, it reduces costs associated with blade icing and UV protection, improving the economic efficiency of wind power generation. The coating also provides additional protective functions, such as UV protection and corrosion resistance, further extending blade lifespan and performance.

[0047] The second aspect of this invention discloses a method for preparing a thermal storage coating for wind turbine blades, specifically including the following steps:

[0048] Step 1: Prepare expanded graphite;

[0049] Weigh an appropriate amount of expanded graphite raw material and place it in a microwave oven. Heat it at 800W for 2-3 minutes. Place the expanded graphite in a vacuum oven at 100-120℃ (vacuum degree -0.07-0.1MPa) for 2 hours. After drying, you will obtain expanded graphite.

[0050] The expanded graphite raw material is selected from EG600, EG700 or EG800; the size of the expanded graphite raw material is ≤13um.

[0051] Step 2: Preparation of hydrated salt phase change materials

[0052] Dipotassium hydrogen phosphate hexahydrate, glycine, and disodium hydrogen phosphate dodecahydrate were mixed in a beaker at a mass ratio of 176.67:13.86:0.99. The mixture was then heated and stirred in a water bath at 55°C until it melted into a transparent liquid, thus obtaining a hydrated salt phase change material.

[0053] Step 3: Preparation of thermal storage microcapsules

[0054] Add the expanded graphite prepared in step one to the molten eutectic hydrated salt in step two. After mechanically stirring and mixing for 10-15 minutes, the hydrated salt will penetrate into the pores of the expanded graphite, resulting in a eutectic hydrated salt / graphite mixture, which is a microcapsule suspension.

[0055] The mass fraction of the expanded graphite is 5% to 15%.

[0056] Step 4: Preparation of thermal storage coating

[0057] The thermal storage coating comprises a water-based polyaspartic acid ester polyurea base (the total mass of polyetheramine, polyaspartic acid ester and diisocyanate), a binder, and a phase change filler, with the mass contents of each component being 40%–50%, 20%–30%, and 20%–40%, respectively.

[0058] (1) Weigh polyetheramine and polyaspartic acid ester according to the above proportions and place them in a four-necked flask for vacuum drying. The vacuum drying conditions are: 100~105℃, -0.07~-0.04MPa, and 1~1.5h.

[0059] (2) Weigh the diisocyanate according to the above proportion and place it in a constant pressure titration funnel.

[0060] (3) Weigh the binder and phase change filler according to the above proportions. Their mass contents in the coating are 20% to 30% and 20% to 40%, respectively, and place them in constant pressure funnels.

[0061] (4) Take the four-necked flask containing polyetheramine and polyaspartic acid ester from step (1) out of the vacuum drying oven, introduce nitrogen into it and turn on the stirrer to cool it down to 30-50°C.

[0062] (5) Open the constant pressure funnel containing the PTFE emulsion binder in step (3), drop the binder into the four-necked flask in step (4), the dropping time is 1 to 2 hours, and start stirring. The stirring conditions are 40 to 70 r / min. After the dropping is completed, stop stirring to obtain process mixture one.

[0063] (6) Open the constant pressure funnel containing the phase change packing in step (3), add the phase change packing dropwise into the four-necked flask in step (5), the dropwise addition time is 1 to 2 hours, and start stirring, the stirring conditions are 50 to 60 r / min, after the dropwise addition is completed, stop stirring to obtain process mixture two.

[0064] (7) Open the constant pressure titration funnel in step (2) and add diisocyanate dropwise into the four-necked flask at a uniform rate for 1 to 1.5 hours to obtain process mixture three.

[0065] (8) After the titration is complete, rinse the constant pressure titration funnel with a certain amount of dipropylene glycol dimethyl ether and add it to the four-necked flask. Heat the mixture to 50-70°C and react at a constant temperature for 2-3 hours.

[0066] (9) Replace the constant pressure titration funnel and slowly add deionized water to the reaction product of step (8), and turn on the stirring. If the dropping speed is too fast, it will easily lead to uneven dispersion and agglomeration. The dropping time is 0.5 to 1 hour, the stirring speed is 1000 to 1300 r / min, and the stirring time is 0.3 to 0.5 hours, thus obtaining the process mixture four.

[0067] (10) Weigh the water-based isocyanate according to the weight of the process mixture after the reaction product is modified in step (9). The ratio of the two is calculated as n(—NCO):n(—NH)=1.2:1. Stir the two thoroughly and mix them evenly to finally obtain the heat storage coating.

[0068] The third aspect of this invention discloses the application of the aforementioned thermal storage coating. When applied, this coating is sprayed or coated onto wind turbine blades. During the daytime when temperatures are high, the hydrated salt phase change material continuously absorbs heat and undergoes a phase change to become liquid. Even after reaching the transition temperature of 55°C, the phase change material continues to absorb heat, resulting in a temperature plateau. At night when ambient temperatures drop, the hydrated salt phase change material begins to release heat, preventing blade icing.

[0069] The following analysis, combined with specific embodiments, provides further explanation:

[0070] Example 1

[0071] Step 1: Prepare expanded graphite;

[0072] Weigh an appropriate amount of EG700 as the expanded graphite raw material, place it in a microwave oven, and microwave it for 2.5 minutes at a power of 800W. Place the expanded graphite in a drying oven at 105℃ (vacuum degree -0.07~0.1MPa) for 2 hours. After drying, expanded graphite is obtained.

[0073] Step 2: Preparation of hydrated salt phase change materials

[0074] Dipotassium hydrogen phosphate hexahydrate and disodium hydrogen phosphate dodecahydrate were mixed in a beaker at a mass ratio of 176.67:13.86:0.99 and heated and stirred in a water bath at 55°C until they melted into a transparent liquid, thus obtaining a hydrated salt phase change material.

[0075] Step 3: Preparation of thermal storage microcapsules

[0076] Add the expanded graphite prepared in step one to the molten eutectic hydrated salt in step two, wherein the mass fraction of the eutectic hydrated salt is 90% and the mass fraction of the expanded graphite is 10%. After mechanically stirring and mixing the two for 15 minutes, a eutectic hydrated salt / graphite mixture is obtained.

[0077] Step 4: Preparation of thermal storage coating

[0078] The mass percentage of waterborne polyaspartic acid ester polyurea base material was set at 45%, the mass percentage of binder at 25%, and the mass percentage of phase change filler at 35%.

[0079] (1) Weigh polyetheramine and polyaspartic acid ester in a molar ratio of 1:5 and place them in a four-necked flask for vacuum drying. The vacuum drying conditions are: 102℃, -0.06MPa, and 1.5h. In this example, the polyetheramine is polyetheramine M230, and the molar ratio of polyaspartic acid ester F420 to polyaspartic acid ester F520 in the polyaspartic acid ester is 4.5:1.

[0080] (2) Weigh the diisocyanate according to the molar ratio of polyetheramine to diisocyanate of 1:1.2 and place it in a constant pressure titration funnel. In this example, the diisocyanate is isoflurone diisocyanate.

[0081] (3) The binder and phase change filler are respectively 25% and 35% in the coating by mass, and are placed in constant pressure funnels respectively.

[0082] (4) Take the four-necked flask containing polyetheramine and polyaspartic acid ester from step (1) out of the vacuum drying oven, introduce nitrogen into it and turn on the stirrer to cool it down to 40°C.

[0083] (5) Open the constant pressure funnel containing the PTFE emulsion binder in step (3), drop the binder into the four-necked flask in step (4), add it over a period of 1.5 hours, and start stirring at 50 r / min. Stop stirring after the addition is complete.

[0084] (6) Open the constant pressure funnel containing the phase change packing from step (3), and dropwise add the phase change packing into the four-necked flask from step (5). The dropping time is 1.5 hours, and the stirring is started at 55 r / min. Stirring is stopped after the dropping is completed.

[0085] (7) Open the constant pressure titration funnel from step (2) and add diisocyanate dropwise into the four-necked flask at a constant rate for 1.2 hours. The molar ratio of polyetheramine to diisocyanate is 1:1.2.

[0086] (8) After the titration is complete, rinse the constant pressure titration funnel with a certain amount of dipropylene glycol dimethyl ether and add it to the four-necked flask. Heat the mixture to 60°C and react at a constant temperature for 2.5 hours.

[0087] (9) Replace the constant pressure titration funnel and slowly add deionized water to the reaction product of step (8). The addition time is 0.8h, the stirring speed is 1200r / min, and the stirring time is 0.4h, thus obtaining the process mixture four.

[0088] (10) Weigh the water-based isocyanate according to the weight of the process mixture after the reaction product is modified in step (9). The ratio of the two is calculated as n(—NCO):n(—NH)=1.2:1. Stir the two thoroughly and mix them evenly to finally obtain the heat storage coating.

[0089] Example 2

[0090] Step 1: Prepare expanded graphite;

[0091] Weigh an appropriate amount of EG600 as the expanded graphite raw material, place it in a microwave oven, and microwave it for 2 minutes at a power of 800W. Place the expanded graphite in a drying oven at 110℃ (vacuum degree -0.07~0.1MPa) for 2 hours. After drying, expanded graphite is obtained.

[0092] Step 2: Preparation of hydrated salt phase change materials

[0093] Dipotassium hydrogen phosphate hexahydrate and disodium hydrogen phosphate dodecahydrate were mixed in a beaker at a mass ratio of 176.67:13.86:0.99 and heated and stirred in a water bath at 55°C until they melted into a transparent liquid, thus obtaining a hydrated salt phase change material.

[0094] Step 3: Preparation of thermal storage microcapsules

[0095] Add the expanded graphite prepared in step one to the molten eutectic hydrated salt in step two, wherein the mass fraction of the eutectic hydrated salt is 85% and the mass fraction of the expanded graphite is 15%. After mechanically stirring and mixing the two for 12 minutes, a eutectic hydrated salt / graphite mixture is obtained.

[0096] Step 4: Preparation of thermal storage coating

[0097] The mass percentage of waterborne polyaspartic acid ester polyurea base material was set at 50%, the mass percentage of binder at 30%, and the mass percentage of phase change filler at 20%.

[0098] (1) Weigh polyetheramine and polyaspartic acid ester in a molar ratio of 1:5 and place them in a four-necked flask for vacuum drying. The vacuum drying conditions are: 102℃, -0.06MPa, and 1.5h. In this example, the polyetheramine is polyetheramine M230, and the molar ratio of polyaspartic acid ester F420 to polyaspartic acid ester F520 in the polyaspartic acid ester is 4.5:1.

[0099] (2) Weigh the diisocyanate according to the molar ratio of polyetheramine to diisocyanate of 1:1.2 and place it in a constant pressure titration funnel. In this example, the diisocyanate is isoflurone diisocyanate.

[0100] (3) The binder and phase change filler are respectively 25% and 35% in the coating by mass, and are placed in constant pressure funnels respectively.

[0101] (4) Take the four-necked flask containing polyetheramine and polyaspartic acid ester from step (1) out of the vacuum drying oven, introduce nitrogen into it and turn on the stirrer to cool it down to 40°C.

[0102] (5) Open the constant pressure funnel containing the PTFE emulsion binder in step (3), drop the binder into the four-necked flask in step (4), add it over a period of 1.5 hours, and start stirring at 50 r / min. Stop stirring after the addition is complete.

[0103] (6) Open the constant pressure funnel containing the phase change packing from step (3), and dropwise add the phase change packing into the four-necked flask from step (5). The dropping time is 1.5 hours, and the stirring is started at 55 r / min. Stirring is stopped after the dropping is completed.

[0104] (7) Open the constant pressure titration funnel from step (2) and add diisocyanate dropwise into the four-necked flask at a constant rate for 1.2 hours. The molar ratio of polyetheramine to diisocyanate is 1:1.2.

[0105] (8) After the titration is complete, rinse the constant pressure titration funnel with a certain amount of dipropylene glycol dimethyl ether and add it to the four-necked flask. Heat the mixture to 60°C and react at a constant temperature for 2.5 hours.

[0106] (9) Replace the constant pressure titration funnel and slowly add deionized water to the reaction product of step (8). The addition time is 0.8h, the stirring speed is 1200r / min, and the stirring time is 0.4h, thus obtaining the process mixture four.

[0107] (10) Weigh the water-based isocyanate according to the weight of the process mixture after the reaction product is modified in step (9). The ratio of the two is calculated as n(—NCO):n(—NH)=1.2:1. Stir the two thoroughly and mix them evenly to finally obtain the heat storage coating.

[0108] Example 3

[0109] Step 1: Prepare expanded graphite;

[0110] Weigh an appropriate amount of EG700 as the expanded graphite raw material, place it in a microwave oven, and microwave it for 2.5 minutes at a power of 800W. Place the expanded graphite in a drying oven at 100℃ (vacuum degree -0.07~0.1MPa) for 2 hours. After drying, expanded graphite is obtained.

[0111] Step 2: Preparation of hydrated salt phase change materials

[0112] Dipotassium hydrogen phosphate hexahydrate and disodium hydrogen phosphate dodecahydrate were mixed in a beaker at a mass ratio of 176.67:13.86:0.99 and heated and stirred in a water bath at 55°C until they melted into a transparent liquid, thus obtaining a hydrated salt phase change material.

[0113] Step 3: Preparation of thermal storage microcapsules

[0114] Add the expanded graphite prepared in step one to the molten eutectic hydrated salt in step two, wherein the mass fraction of the eutectic hydrated salt is 95% and the mass fraction of the expanded graphite is 5%. After mechanically stirring and mixing the two for 10 minutes, a eutectic hydrated salt / graphite mixture is obtained.

[0115] Step 4: Preparation of thermal storage coating

[0116] The mass percentage of waterborne polyaspartic acid ester polyurea base material was set at 50%, the mass percentage of binder at 20%, and the mass percentage of phase change filler at 30%.

[0117] (1) Weigh polyetheramine and polyaspartic acid ester in a molar ratio of 1:3 and place them in a four-necked flask for vacuum drying. The vacuum drying conditions are: 100℃, -0.07MPa, and 1h. In this example, the polyetheramine is polyetheramine M1000, and the molar ratio of polyaspartic acid ester F420 to polyaspartic acid ester F520 in the polyaspartic acid ester is 4:1.

[0118] (2) Weigh the diisocyanate according to the molar ratio of polyetheramine and diisocyanate of 1:1 and place it in a constant pressure titration funnel. In this example, the diisocyanate is hexamethylene diisocyanate.

[0119] (3) Place the binder and phase change filler into constant pressure funnels respectively.

[0120] (4) Take the four-necked flask containing polyetheramine and polyaspartic acid ester from step (1) out of the vacuum drying oven, introduce nitrogen into it and turn on the stirrer to cool it down to 30°C.

[0121] (5) Open the constant pressure funnel containing the PTFE emulsion binder in step (3), drop the binder into the four-necked flask in step (4), add it over a period of 1 hour, and start stirring at 40 r / min. Stop stirring after the addition is complete.

[0122] (6) Open the constant pressure funnel containing the phase change packing from step (3), and dropwise add the phase change packing into the four-necked flask from step (5). The dropping time is 1 hour, and the stirring is started at 50 r / min. After the dropping is completed, the stirring is stopped.

[0123] (7) Open the constant pressure titration funnel from step (2) and add diisocyanate dropwise into the four-necked flask at a constant rate for 1 hour. The molar ratio of polyetheramine to diisocyanate is 1:1.1.

[0124] (8) After the titration is complete, rinse the constant pressure titration funnel with a certain amount of dipropylene glycol dimethyl ether and add it to the four-necked flask. Heat the mixture to 50°C and react at a constant temperature for 3 hours.

[0125] (9) Replace the constant pressure titration funnel and slowly add deionized water to the reaction product of step (8). The addition time is 0.5h, the stirring speed is 1300r / min, and the stirring time is 0.3h to obtain the process mixture four.

[0126] (10) Weigh the water-based isocyanate according to the weight of the process mixture after the reaction product is modified in step (9). The ratio of the two is calculated as n(—NCO):n(—NH)=1.2:1. Stir the two thoroughly and mix them evenly to finally obtain the heat storage coating.

[0127] Example 4

[0128] Step 1: Prepare expanded graphite;

[0129] Weigh an appropriate amount of EG800 as the expanded graphite raw material, place it in a microwave oven, and microwave it for 3 minutes at a power of 800w. Place the expanded graphite in a vacuum oven at 120℃ (vacuum degree -0.07~0.1MPa) for 2 hours. After drying, expanded graphite is obtained.

[0130] Step 2: Preparation of hydrated salt phase change materials

[0131] Dipotassium hydrogen phosphate hexahydrate and disodium hydrogen phosphate dodecahydrate were mixed in a beaker at a mass ratio of 176.67:13.86:0.99 and heated and stirred in a water bath at 55°C until they melted into a transparent liquid, thus obtaining a hydrated salt phase change material.

[0132] Step 3: Preparation of thermal storage microcapsules

[0133] Add the expanded graphite prepared in step one to the molten eutectic hydrated salt in step two, wherein the mass fraction of the eutectic hydrated salt is 95% and the mass fraction of the expanded graphite is 5%. After mechanically stirring and mixing the two for 15 minutes, a eutectic hydrated salt / graphite mixture is obtained.

[0134] Step 4: Preparation of thermal storage coating

[0135] The mass percentages of waterborne polyaspartic acid ester polyurea base material were set at 40%, binder at 30%, and phase change filler at 30%.

[0136] (1) Weigh polyetheramine and polyaspartic acid ester in a molar ratio of 1:8 and place them in a four-necked flask for vacuum drying. The vacuum drying conditions are: 105℃, -0.04MPa, and 1.2h. In this example, the polyetheramine is polyetheramine M200, and the molar ratio of polyaspartic acid ester F420 to polyaspartic acid ester F520 in the polyaspartic acid ester is 8:1.

[0137] (2) Weigh the diisocyanate according to the molar ratio of polyetheramine to diisocyanate of 1:1.3 and place it in a constant pressure titration funnel. In this example, the diisocyanate is 4,4'-dicyclohexylmethane diisocyanate.

[0138] (3) Place the binder and phase change filler in a constant pressure funnel respectively.

[0139] (4) Take the four-necked flask containing polyetheramine and polyaspartic acid ester from step (1) out of the vacuum drying oven, introduce nitrogen into it and turn on the stirrer to cool it down to 50°C.

[0140] (5) Open the constant pressure funnel containing the PTFE emulsion binder in step (3), drop the binder into the four-necked flask in step (4), add it over a period of 2 hours, and start stirring at 70 r / min. Stop stirring after the addition is complete.

[0141] (6) Open the constant pressure funnel containing the phase change packing from step (3), and dropwise add the phase change packing into the four-necked flask from step (5). The dropping time is 2 hours, and the stirring is started at 60 r / min. Stirring is stopped after the dropping is completed.

[0142] (7) Open the constant pressure titration funnel from step (2) and add diisocyanate dropwise into the four-necked flask at a constant rate for 1.5 hours. The molar ratio of polyetheramine to diisocyanate is 1:1.3.

[0143] (8) After the titration is complete, rinse the constant pressure titration funnel with a certain amount of dipropylene glycol dimethyl ether and add it to the four-necked flask. Heat the mixture to 70°C and react at a constant temperature for 2 hours.

[0144] (9) Replace the constant pressure titration funnel and slowly add deionized water to the reaction product of step (8). The addition time is 1 hour, the stirring speed is 1000 r / min, and the stirring time is 0.5 hours to obtain the process mixture four.

[0145] (10) Weigh the water-based isocyanate according to the weight of the process mixture after the reaction product is modified in step (9). The ratio of the two is calculated as n(—NCO):n(—NH)=1.2:1. Stir the two thoroughly and mix them evenly to finally obtain the heat storage coating.

[0146] Example 5

[0147] Step 1: Prepare expanded graphite;

[0148] Weigh an appropriate amount of EG800 as the expanded graphite raw material, place it in a microwave oven, and microwave it for 3 minutes at a power of 800w. Place the expanded graphite in a vacuum oven at 120℃ (vacuum degree -0.07~0.1MPa) for 2 hours. After drying, expanded graphite is obtained.

[0149] Step 2: Preparation of hydrated salt phase change materials

[0150] Dipotassium hydrogen phosphate hexahydrate and disodium hydrogen phosphate dodecahydrate were mixed in a beaker at a mass ratio of 176.67:13.86:0.99 and heated and stirred in a water bath at 55°C until they melted into a transparent liquid, thus obtaining a hydrated salt phase change material.

[0151] Step 3: Preparation of thermal storage microcapsules

[0152] Add the expanded graphite prepared in step one to the molten eutectic hydrated salt in step two, wherein the mass fraction of the eutectic hydrated salt is 95% and the mass fraction of the expanded graphite is 5%. After mechanically stirring and mixing the two for 15 minutes, a eutectic hydrated salt / graphite mixture is obtained.

[0153] Step 4: Preparation of thermal storage coating

[0154] The mass percentage of waterborne polyaspartic acid ester polyurea base material was set at 40%, the mass percentage of binder at 20%, and the mass percentage of phase change filler at 40%.

[0155] (1) Weigh polyetheramine and polyaspartic acid ester in a molar ratio of 1:8 and place them in a four-necked flask for vacuum drying. The vacuum drying conditions are: 105℃, -0.04MPa, and 1.2h. In this example, the polyetheramine is polyetheramine M200, and the molar ratio of polyaspartic acid ester F420 to polyaspartic acid ester F520 in the polyaspartic acid ester is 5:1.

[0156] (2) Weigh the diisocyanate according to the molar ratio of polyetheramine to diisocyanate of 1:1.3 and place it in a constant pressure titration funnel. In this example, the diisocyanate is 4,4'-dicyclohexylmethane diisocyanate.

[0157] (3) Place the binder and phase change filler in a constant pressure funnel respectively.

[0158] (4) Take the four-necked flask containing polyetheramine and polyaspartic acid ester from step (1) out of the vacuum drying oven, introduce nitrogen into it and turn on the stirrer to cool it down to 50°C.

[0159] (5) Open the constant pressure funnel containing the PTFE emulsion binder in step (3), drop the binder into the four-necked flask in step (4), add it over a period of 2 hours, and start stirring at 40 r / min. Stop stirring after the addition is complete.

[0160] (6) Open the constant pressure funnel containing the phase change packing from step (3), and dropwise add the phase change packing into the four-necked flask from step (5). The dropping time is 2 hours, and the stirring is started at 50 r / min. After the dropping is completed, the stirring is stopped.

[0161] (7) Open the constant pressure titration funnel from step (2) and add diisocyanate dropwise into the four-necked flask at a constant rate for 1.5 hours. The molar ratio of polyetheramine to diisocyanate is 1:1.3.

[0162] (8) After the titration is complete, rinse the constant pressure titration funnel with a certain amount of dipropylene glycol dimethyl ether and add it to the four-necked flask. Heat the mixture to 70°C and react at a constant temperature for 2 hours.

[0163] (9) Replace the constant pressure titration funnel and slowly add deionized water to the reaction product of step (8). The addition time is 1 hour, the stirring speed is 1000 r / min, and the stirring time is 0.3 hours to obtain the process mixture four.

[0164] (10) Weigh the water-based isocyanate according to the weight of the process mixture after the reaction product is modified in step (9). The ratio of the two is calculated as n(—NCO):n(—NH)=1.2:1. Stir the two thoroughly and mix them evenly to finally obtain the heat storage coating.

[0165] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A heat storage coating for wind turbine blades, characterized in that, The product comprises, by mass fraction, 40%–50% waterborne polyaspartic acid ester polyurea base resin, 20%–30% binder, and 20%–40% heat storage microcapsules; the binder is an aqueous PTFE emulsion; the heat storage microcapsules are dispersed in the waterborne polyaspartic acid ester polyurea base resin. The heat storage microcapsule is composed of expanded graphite and hydrated salt phase change material. The hydrated salt phase change material fills the pores of the expanded graphite. The hydrated salt phase change material is composed of dipotassium hydrogen phosphate hexahydrate, glycine and disodium hydrogen phosphate dodecahydrate. In the heat storage microcapsule, the mass fraction of expanded graphite is 5%~15%, and the balance is hydrated salt phase change material; the mass ratio of dipotassium hydrogen phosphate hexahydrate, glycine, and disodium hydrogen phosphate dodecahydrate is 176.67:13.86:0.99; the expanded graphite is any one or more of EG600, EG700, or EG800; the raw material size of the expanded graphite is ≤13μm; The waterborne polyaspartic acid ester polyurea-based resin is composed of a heat-storing polyaspartic acid ester dispersion and a waterborne isocyanate. The heat-storing polyaspartic acid ester dispersion is composed of polyetheramine, polyaspartic acid ester and diisocyanate. In the heat storage polyaspartic acid ester dispersion, the mass ratio of polyaspartic acid ester to polyetheramine is (3~8):1, and the molar ratio of polyetheramine to diisocyanate is 1:(1~1.3).

2. A method for preparing a thermal storage coating for wind turbine blades as described in claim 1, characterized in that, Includes the following steps: Step 1: Add the hydrated salt phase change material to the expanded graphite and stir until homogeneous to obtain a heat storage microcapsule suspension. Step 2: Add PTFE emulsion dropwise to the mixture of polyetheramine and polyaspartic acid ester, and stir evenly after addition to obtain process mixture one; Step 3: Add heat storage microcapsule suspension dropwise to process mixture one, stir evenly to obtain process mixture two; Step 4: Add diisocyanate dropwise to process mixture two to obtain process mixture three; Step 5: Add water dropwise to process mixture three, stir evenly to obtain a mixture of thermal storage polyaspartic acid ester dispersion, PTFE emulsion and thermal storage microcapsules; Step 6: Add aqueous isocyanate dropwise to the mixture obtained in step 5, stir evenly, and obtain the heat storage coating.

3. The method for preparing a thermal storage coating for wind turbine blades according to claim 2, characterized in that, In step 1, the preparation process of the hydrated salt phase change material is as follows: dipotassium hydrogen hydrate, glycine and disodium hydrogen phosphate dodecahydrate are mixed in a mass ratio of 176.67:13.86:0.99, placed in a water bath at 55°C and heated and stirred until melted into a transparent liquid to obtain the hydrated salt phase change material.

4. The method for preparing a thermal storage coating for wind turbine blades according to claim 2, characterized in that, In step 2, the PTFE emulsion is added over a period of 1 to 2 hours, and the stirring rate is 40 to 70 r / min.

5. The method for preparing a thermal storage coating for wind turbine blades according to claim 2, characterized in that, In step 3, the heat storage microcapsule suspension is added dropwise over a period of 1-2 hours, and the stirring rate is 50-60 r / min.

6. The method for preparing a thermal storage coating for wind turbine blades according to claim 2, characterized in that, In step 6, the amount of aqueous isocyanate added is determined by the mass of the polyaspartic ester dispersion, and the molar ratio of -NH in the polyaspartic ester dispersion to -NCO in the aqueous isocyanate is 1.2:1.

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