CN117603609A

CN117603609A - An adaptive thermochromic composite coating and its preparation method and application

Info

Publication number: CN117603609A
Application number: CN202311550782.1A
Authority: CN
Inventors: 李宾宾; 罗沙; 邱曼曼; 田宇; 柯艳国; 王刘芳; 邱欣杰; 程登峰; 朱太云; 朱胜龙; 陈庆涛; 黄杰; 马亚彬; 汪玉; 李坚林; 甄超; 姜源; 温睿; 韦健; 金晶
Original assignee: Electric Power Research Institute of State Grid Anhui Electric Power Co Ltd
Current assignee: Electric Power Research Institute of State Grid Anhui Electric Power Co Ltd
Priority date: 2023-11-16
Filing date: 2023-11-16
Publication date: 2024-02-27
Anticipated expiration: 2043-11-16
Also published as: CN117603609B

Abstract

The invention discloses a preparation method of a thermochromic composite coating with self-adaptive conductivity, which comprises the following steps: the thermochromic material comprises base resin, thermochromic mixed pigment, filler and solvent; uniformly mixing and stirring base resin, pigment, filler and solvent to prepare color paste, and transferring the color paste into a high-speed ball-ink machine for grinding and dispersing for 2 hours to prepare the thermochromic coating; microencapsulation of thermochromic paint; mixing the microencapsulated thermochromic coating and nonlinear conductive filler, and ball milling; adding the melted epoxy resin, stirring and mixing uniformly; adding a curing agent and a diluent for dilution, and fully stirring and mixing to obtain a mixture; the mixture is sprayed or brushed on the surface of the insulating piece to form the thermochromic composite coating with self-adaptive conductivity. The preparation method provided by the invention is simple and feasible, has low cost and has wide application prospect.

Description

Self-adaptive thermochromic composite coating and preparation method and application thereof

Technical Field

The invention belongs to the technical field of operation and maintenance of high-voltage power equipment, and particularly relates to a thermochromic composite coating with self-adaptive conductivity, and a preparation method and application thereof.

Background

The load centers and the energy resources in China are unevenly distributed, and a long-distance large-capacity power transmission mode is needed to solve the power utilization problem of the load centers. In order to reduce the power transmission cost, direct current power transmission engineering is greatly developed. The power equipment in the direct current power system is electrified to operate for a long time 24 hours, and the insulation of the power equipment is gradually aged along with the increase of the operation period, so that abnormal heating is brought, and the overheat fault of the power equipment can be caused by the long-time overheat operation. There are a large number of connection points between various kinds of power equipment in the power system, such as connection of a high-voltage cable and a GIS/transformer outlet sleeve, connection of a moving contact and a fixed contact of a circuit breaker, a switch contact and the like, and the connection points may be hot spots due to increase of contact resistance caused by poor contact in the operation process of the power equipment. Before faults occur, the temperature of many direct current power equipment can be greatly increased, so that fault early warning can be realized by detecting the temperature change of the equipment, measures can be taken in advance, and a series of adverse chain reactions caused by the faults are avoided.

The temperature measurement modes in the current common power system mainly comprise infrared temperature measurement, thermocouple temperature measurement, fiber bragg grating sensor temperature measurement and other modes. The infrared temperature measurement response speed is high, the sensitivity is high, the measurable temperature range is large, but the equipment is relatively expensive, the application range is narrow, the infrared temperature measurement device is suitable for measuring the external temperature of the power equipment, and the infrared temperature measurement device is only arranged for some important power equipment at present; the thermocouple temperature measurement is a contact type temperature measurement mode, has a simple structure and good stability, but has poor noise resistance and is easily influenced by environmental temperature change; the fiber bragg grating sensor has the advantages of high stability, high measurement accuracy, good insulation performance and electromagnetic interference resistance, but has a complex optical coupling loop in application, and has certain limitation. Therefore, the study is suitable for the temperature measurement modes with large area, various types and wide range in the power system, and has important significance for guaranteeing the reliable operation of the power equipment and reducing the fault rate.

The prior art publication number CA109135723A discloses an aerogel composite material with a thermochromic function and a preparation method thereof, the aerogel composite material consists of aerogel and a composite coating with the thermochromic function, and the composite coating consists of a transition layer, a thermochromic functional layer and a surface protection layer. On the premise of retaining the original excellent characteristics of the aerogel, the aerogel is endowed with a thermochromic function, namely the optical performance of the aerogel is intelligently adjusted through the change of the ambient temperature. But aerogel composites cannot be used in electrical equipment with heat dissipation requirements.

Disclosure of Invention

The technical problem to be solved by the invention is how to prepare the thermochromic composite coating with self-adaptive conductivity in a direct current environment.

The invention solves the technical problems by the following technical means:

the first aspect of the invention provides a method for preparing a thermochromic composite coating with self-adaption, comprising the following steps:

step 1: preparation of thermochromic paint

The thermochromic material comprises base resin, thermochromic mixed pigment, filler and solvent; uniformly mixing and stirring base resin, pigment, filler and solvent to prepare color paste, and transferring the color paste into a high-speed ball-ink machine for grinding and dispersing to prepare the thermochromic coating;

step 2: microencapsulation of thermochromic coatings

1) Taking a proper amount of the carbonamide in a beaker, adding formaldehyde solution, and magnetically stirring until the carbonamide is completely dissolved; adding an ethanol solution to the mixture, and adjusting the pH to be slightly alkaline; then heating in water bath, stirring and cooling to room temperature to obtain a prepolymer solution;

2) Taking a proper amount of gum arabic powder and deionized water, heating and stirring in a constant-temperature water bath, and cooling to room temperature for standby; adding thermochromic paint serving as a core material into the standby solution, stirring under the water bath condition, and continuing stirring after the water bath temperature is reduced to form a core material solution;

3) Gradually dripping the prepolymer solution into the core material solution, and adding an acetic acid solution to adjust the pH value of the mixed solution to be neutral and strong acid; adding proper amount of sodium chloride and silicon dioxide into a strong acid solution, raising the temperature of a water bath, magnetically stirring, cooling, drying at constant temperature, and grinding into powder to obtain the microencapsulated thermochromic coating.

Step 3: compounding of self-adaptive conductive fillers

Mixing the microencapsulated thermochromic coating and nonlinear conductive filler, and ball milling; adding the melted epoxy resin, stirring and mixing uniformly; adding a curing agent and a diluent for dilution, and fully stirring and mixing to obtain a mixture; the mixture is sprayed or brushed on the surface of the insulating piece to form the self-adaptive thermochromic composite coating.

The beneficial effects are that: the invention considers the operation environment suitable for power equipment, the thermochromic material is selected from materials with low cost, wide color change interval and strong weather resistance, and the thermochromic pigment with good stability and processability is selected, so that the invention can meet the large-area wide-range temperature measurement requirement in a power system on the premise of considering economical efficiency.

In order to ensure the compatibility between the thermochromic coating and the self-adaptive conductive filler, the thermochromic coating is treated by adopting a microencapsulation technology.

Preferably, the base resin is an epoxy resin or a silicone resin.

Preferably, the thermochromic mixed pigment is nickel sulfate, manganese sulfate, cobalt sulfate, copper sulfate mixture or cobalt sulfate, copper sulfate, manganese sulfate mixture or manganese sulfate and copper sulfate mixture; mixing the nickel sulfate, the manganese sulfate, the cobalt sulfate and the copper sulfate according to the mass ratio of 5:1:1:2; the cobalt sulfate, the copper sulfate and the manganese sulfate are mixed according to the mass ratio of 1:2:1; and mixing the manganese sulfate and the copper sulfate according to the mass ratio of 2:1.

Preferably, the filler is titanium oxide and aluminum oxide, and the solvent is dimethylbenzene; the dispersion time was 2h.

Preferably, the base resin, the thermochromic mixed pigment, the filler and the solvent are mixed according to a mass ratio of 3:4:3:3.

Preferably, the carboxamide and formaldehyde solution in the step 1) are mixed according to the mass ratio of (1-4): 5-15.

Preferably, the weak alkaline pH is 8.0-9.0; the water bath temperature is 70-80 ℃, and the stirring time is 1h.

Preferably, the gum arabic powder and deionized water in the step 2) are mixed according to the mass ratio of (0.5-2) (9-13), and heated in a constant-temperature water bath at 50-60 ℃.

Preferably, the pH of the strong acidity is 2.0 to 3.0; the water bath temperature was 90℃and the temperature was reduced to 65 ℃.

Preferably, in the step 3), sodium chloride and silicon dioxide are added into a strong acid solution according to a mass ratio of 1:1; the water bath temperature was raised to 90 ℃.

The beneficial effects are that: according to the invention, the thermochromic material is used as a capsule core material, the carbonamide is used as a capsule wall material, the gum arabic is used as an emulsifier, the acetic acid is used as a pH regulator, and the sodium chloride and the silicon dioxide are used as additives, so that the hardness of the microcapsule wall is improved.

Preferably, the nonlinear conductive filler is SiC particles, znO particles, or other particles whose conductivity varies positively with the electric field.

Preferably, the curing agent is polyamide and the diluent is acetone.

The second aspect of the invention provides a thermochromic composite coating with self-adaption prepared by the preparation method.

The beneficial effects are that: the self-adaptive thermochromic composite coating prepared by the invention can realize the dual functions of overheat early warning and intelligent regulation and control of the distribution of the electric field along the surface of the power equipment.

A third aspect of the present invention provides the use of the above described thermochromic composite coating with adaptation in an electrical device.

The invention has the advantages that:

the invention considers the operation environment suitable for power equipment, the thermochromic material is selected from materials with low cost, wide color change range and strong weather resistance, and the thermochromic pigment with good stability and processability is selected.

In order to ensure the compatibility between the thermochromic coating and the self-adaptive conductivity filler, the thermochromic coating is treated by adopting a microencapsulation technology.

According to the invention, the thermochromic material is used as a capsule core material, the carbonamide is used as a capsule wall material, the gum arabic is used as an emulsifier, the acetic acid is used as a pH regulator, and the sodium chloride and the silicon dioxide are used as additives, so that the hardness of the microcapsule wall is improved.

The self-adaptive thermochromic composite coating prepared by the invention can realize the dual functions of overheat early warning and intelligent regulation and control of the distribution of the electric field along the surface of the power equipment.

Drawings

FIG. 1 is a flow chart of the present invention for preparing a thermochromic composite coating having an adaptation;

FIG. 2 is a graph showing the discoloration of the thermochromic composite prepared in example 1 at various temperatures;

FIG. 3 is a graph showing the color change of the thermochromic composite material with adaptation prepared in example 2 at different temperatures;

FIG. 4 is a graph showing the conductivity distribution of the thermochromic composite with adaptation prepared in example 2 under different electric fields;

FIG. 5 is an electric field distribution of an insulator with an adaptive thermochromic composite coating of example 2;

FIG. 6 is a scanning electron microscope image of particles before and after microencapsulation of example 2;

fig. 7 is the voltage across the insulator surface flashover before and after microencapsulation of example 2.

Detailed Description

For the purpose of making the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the technical solutions in the embodiments of the present invention will be clearly and completely described in the following in conjunction with the embodiments of the present invention, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

The test materials, reagents and the like used in the examples described below are commercially available unless otherwise specified.

Those of skill in the art, without any particular mention of the techniques or conditions, may follow the techniques or conditions described in the literature in this field or follow the product specifications.

Example 1

The preparation method of the thermochromic composite coating with self-adaption comprises the following steps:

step 1: preparation of thermochromic paint

The base resin is organic silicon resin, the thermochromic mixed pigment is prepared by mixing manganese sulfate and copper sulfate, the filler is titanium oxide and aluminum oxide, and the solvent is dimethylbenzene. 9g of organic silicon resin, 12g of pigment (wherein manganese sulfate is 4g, copper sulfate is 8 g), 6g of filler and 6g of solvent are weighed, solid particles are firstly ground and crushed, then mixed and stirred uniformly to prepare color paste, the color paste is transferred into a high-speed ball ink machine to be ground and dispersed for 2 hours, and the thermochromic coating is prepared, and the particle size of the coating is measured and controlled below 30 mu m.

Step 2: microencapsulation of thermochromic coatings

1) Taking 8g of carbonamide in a beaker, adding 30g of formaldehyde solution, and magnetically stirring until the mixture is uniformly mixed; adding a proper amount of ethanol solution into the mixture, and adjusting the pH value to 8.0; heating in 70 ℃ water bath, stirring for 1 hour, and cooling to room temperature to obtain a prepolymer solution;

2) Taking 4g of gum arabic powder and 50g of deionized water, heating and stirring in a constant-temperature water bath at 60 ℃, and cooling to room temperature for standby; adding 5g of thermochromic paint serving as a core material into the standby solution, stirring for 10min under the water bath condition of 90 ℃, and then stirring for 10min under the water bath temperature condition of 65 ℃ to form a core material solution;

3) Gradually dripping the prepolymer solution into the core material solution, and adding a proper amount of acetic acid solution until the pH value is 2.0; adding 5g of sodium chloride and 5g of silicon dioxide into a strong acid solution, raising the temperature of a water bath kettle to 90 ℃, magnetically stirring for 1h, cooling, drying at constant temperature for 24h, and grinding into 10-100 mu m powder to obtain the microencapsulated thermochromic coating.

Step 3: compounding of self-adaptive conductivity filler

Weighing 10g of microencapsulated thermochromic coating, weighing 5g of nonlinear conductive filler ZnO particles, mixing, and grinding for 1h by adopting a ball mill for later use; adding 12g of molten organic silicon resin into the mixture, magnetically stirring the mixture for 30min, fully and uniformly mixing the mixture to obtain a mixture, and spraying or brushing the mixture on the surface of an insulating part to form the self-adaptive thermochromic composite coating. The melted organic silicon resin is obtained by heating in a water bath environment of 50-60 ℃ and stirring.

Example 2

step 1: preparation of thermochromic paint

The base resin is epoxy resin, the thermochromic mixed pigment is nickel sulfate, manganese sulfate, cobalt sulfate and copper sulfate, the filler is titanium oxide and aluminum oxide, and the solvent is dimethylbenzene. 9g of epoxy resin, 12g of pigment (6.70 g of nickel sulfate, 1.34g of manganese sulfate, 1.34g of cobalt sulfate and 2.62g of copper sulfate), 9g of filler and 9g of solvent are weighed, solid particles are firstly ground and crushed, then mixed and stirred uniformly to prepare color paste, the color paste is transferred into a high-speed ball-and-ink machine to be ground and dispersed for 2 hours, and the thermochromic coating is prepared, and the particle size of the coating is measured and controlled below 30 mu m.

Step 2: microencapsulation of thermochromic coatings

2) Taking 5g of carbonamide in a beaker, adding 25g of formaldehyde solution, and magnetically stirring until the mixture is uniformly mixed; 2.5g of ethanol solution was added thereto, and the pH was adjusted to 8.5; heating in 75 ℃ water bath, stirring for 1 hour, and cooling to room temperature to obtain a prepolymer solution;

2) Taking 2.5g of gum arabic powder and 45g of deionized water, heating and stirring in a constant-temperature water bath at 50 ℃, and cooling to room temperature for standby; adding 5g of thermochromic paint serving as a core material into the standby solution, stirring for 10min under the water bath condition of 90 ℃, and then stirring for 10min under the water bath temperature condition of 65 ℃ to form a core material solution;

3) Gradually dripping the prepolymer solution into the core material solution, and adding a proper amount of acetic acid solution until the pH value is 2.5; adding 2.5g of sodium chloride and 2.5g of silicon dioxide into a strong acid solution, raising the temperature of a water bath to 90 ℃, magnetically stirring for 1h, cooling, drying at constant temperature for 24h, and grinding into powder of 10-100 mu m to obtain the microencapsulated thermochromic coating.

Step 3: compounding of self-adaptive conductivity filler

Weighing 10g of microencapsulated thermochromic paint, weighing 5g of SiC particles, mixing, and grinding for 1h by adopting a ball mill for later use; adding 10g of molten epoxy resin into the mixture, magnetically stirring the mixture for 30min, and fully and uniformly mixing the mixture; and adding 5g of polyamide ester curing agent, stirring for 30min, adding 5g of acetone diluent, fully stirring and mixing to obtain a mixture, and spraying or brushing the mixture on the surface of an insulating part to form the self-adaptive thermochromic composite coating. The molten epoxy resin is obtained by heating and stirring in a water bath environment at 60 ℃.

According to fig. 3, the color of the thermochromic composite coating with adaptation changes significantly when the temperature reaches 110 ℃, and the coating color gradually deepens as the temperature continues to rise. The temperature range of common overheat faults of the power equipment is 100-120 ℃, so that the thermochromic composite coating with the self-adaption provided by the invention can be suitable for overheat early warning of most power equipment. Further, the change of the conductivity of the thermochromic composite coating with the adaptation with the electric field is measured, and as shown in fig. 4, it can be seen that the conductivity of the thermochromic composite coating with the adaptation gradually shows a nonlinear increase characteristic with the increase of the electric field. The coating of the invention is coated on the insulator shown in figure 5, and the surface electric field distribution of the uncoated and coated insulators along the radial direction is calculated, so that the electric field distribution of the coated insulator is lower than that of the uncoated insulator, and the fact that the thermochromic composite coating with self-adaption has the function of intelligently regulating the surface electric field is shown. According to fig. 6, after the thermochromic coating is microencapsulated, particles become more regular, and a layer of capsule wall material is coated on the periphery, so that the stability of the thermochromic coating can be improved. According to fig. 7, the thermochromic coating of the present invention has significantly higher insulator flashover voltage after microencapsulation than before microencapsulation, further illustrating that microencapsulation can promote compatibility between the two fillers. In conclusion, the thermochromic composite coating with the self-adaption provided by the invention can realize dual functions of overheat early warning and intelligent regulation and control of electric field distribution.

The preparation method of the self-adaptive thermochromic composite coating provided by the invention is simple and feasible, has low cost and has wide application prospect.

The above embodiments are only for illustrating the technical solution of the present invention, and are not limiting; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a thermochromic composite coating with adaptive conductivity, which is characterized by comprising the following steps:

Step 1: Preparation of Thermochromic Coating

Thermochromic materials include base resin, thermochromic mixed pigments, fillers and solvents; mix and stir the base resin, pigments, fillers and solvents evenly to form a color slurry, which is then transferred to a high-speed ductile ink machine for grinding and dispersion. Preparation of thermochromic coating;

Step 2: Microencapsulation of the thermochromic coating

1) Take an appropriate amount of carbonamide in a beaker, add formaldehyde solution, and stir magnetically until the mixture is evenly mixed until the carbonamide is completely dissolved; add ethanol solution to it and adjust the pH to weak alkaline; then heat in a water bath, stir, and then cool to At room temperature, a prepolymer solution is obtained;

2) Take an appropriate amount of gum arabic powder and deionized water, heat and stir in a constant temperature water bath, then cool to room temperature for later use; take thermochromic paint as the core material and add it to the standby solution, stir under water bath conditions, and continue after the water bath temperature drops. Stir to form core material solution;

3) Gradually drip the prepolymer solution into the core material solution, add acetic acid solution to adjust the pH value of the mixed solution to strong acidity; add appropriate amounts of sodium chloride and silicon dioxide into the strong acidic solution, and increase the water bath temperature. After magnetic stirring, it is cooled, dried at a constant temperature, and ground into powder to obtain a microencapsulated thermochromic coating.

Step 3: Compounding of Adaptive Conductivity Fillers

Take the microencapsulated thermochromic coating and nonlinear conductive filler, mix them and ball-mill them; add molten epoxy resin, stir and mix evenly; then add curing agent and diluent to dilute, stir and mix thoroughly to obtain a mixture; spray the mixture Or brush it on the surface of insulating parts to form a thermochromic composite coating with adaptive conductivity.

2. The preparation method according to claim 1, wherein the base resin is an epoxy resin or a silicone resin, and the thermochromic mixed pigment is nickel sulfate, manganese sulfate, cobalt sulfate, copper sulfate mixed with nickel sulfate. , a mixture of manganese sulfate, cobalt sulfate, and copper sulfate or a mixture of cobalt sulfate, copper sulfate, and manganese sulfate, or a mixture of manganese sulfate and copper sulfate, the filler is titanium oxide and aluminum oxide, and the solvent is xylene; the dispersion time is 2 hours.

3. The preparation method according to claim 2, characterized in that the base resin, thermochromic mixed pigment, filler and solvent are mixed according to a mass ratio of 3:4:3:3, and the nickel sulfate, Manganese sulfate, cobalt sulfate, and copper sulfate are mixed according to a mass ratio of 5:1:1:2, and the cobalt sulfate, copper sulfate, and manganese sulfate are mixed according to a mass ratio of 1:2:1; the manganese sulfate, sulfate Copper is mixed at a mass ratio of 2:1.

4. The preparation method according to claim 1, characterized in that, in the step 1), the carbonamide and the formaldehyde solution are mixed according to a mass ratio of (1-4): (5-15); the weak alkalinity The pH is 8.0-9.0; the water bath temperature is 70-80°C, and the stirring time is 1 hour.

5. The preparation method according to claim 1, characterized in that in the step 2), gum arabic powder and deionized water are mixed according to a mass ratio of (0.5-2): (9-13), and the mixture is mixed at 50 -60°C constant temperature water bath for heating; the strongly acidic pH is 2.0-3.0; the water bath temperature is 90°C, and the temperature drops to 65°C.

6. The preparation method according to claim 1, characterized in that in step 3), sodium chloride and silicon dioxide are added to the strong acid solution in a mass ratio of 1:1; and the water bath temperature is raised to 90°C. .

7. The preparation method according to claim 1, characterized in that the nonlinear conductive filler is SiC particles, ZnO particles or other particles whose conductivity changes in a positive correlation with the electric field.

8. The preparation method according to claim 1, wherein the curing agent is polyamide and the diluent is acetone.

9. The preparation method according to any one of claims 1 to 8 produces a thermochromic composite coating with adaptive conductivity.

10. Application of the thermochromic composite coating with adaptive conductivity as claimed in claim 9 in power equipment.