CN116574437A - Self-repairing insulating material for power equipment and preparation method thereof - Google Patents

Abstract

The invention provides a self-repairing insulating material for electric equipment and a preparation method thereof, belonging to the technical field of coating compositions. A self-repairing insulating material for power equipment, made of the following raw materials in parts by weight: 40-50 parts of water-based polyurethane-acrylate composite emulsion, 10-20 parts of self-repairing microcapsules, and 5-12 parts of surface modifier , 3-8 parts of nanoparticles, 10-20 parts of curing agent; wherein: the self-healing microcapsules are made of a capsule wall and a core material, the capsule wall is a modified urea-formaldehyde resin, and the core material is hexamethylene diisocyanate or isophorone diisocyanate. The above technical proposal of the present invention improves the water resistance of the coating and enables the coating to perform self-repair when cracks occur.

Description

A kind of self-repairing insulating material for electric equipment and preparation method thereof

technical field

The invention belongs to the technical field of coating compositions, and in particular relates to a self-repairing insulating material for electric equipment and a preparation method thereof.

Background technique

With the development of society and economy, the scale of power grid construction is expanding day by day, and the safety of power transmission and transformation equipment is becoming more and more important. Due to the long-term exposure of power transmission and transformation equipment in the wild, its components are eroded and damaged by various harsh environments, resulting in a greatly shortened service life and a serious threat to safe operation. At present, a layer of insulating material is usually coated on the surface of the power equipment, which can not only improve the external insulation of the power equipment, improve the safety of the power system, but also improve the reliability of the system operation. There are many types of insulating materials, such as insulating encapsulation materials, insulating paper, insulating plastics, insulating coatings, etc. Among them, insulating coatings are more and more applied to insulating equipment in various industries due to their simple preparation method and convenient construction process. .

However, most of these insulating coatings currently on the market are solvent-based, which contain a large amount of aromatic hydrocarbon organic solvents, such as toluene, xylene, etc. These solvents contain volatile organic compounds (VOC), which will cause smog to form when they are directly released into the environment. Workers cause flammability and inhalation risks, and increase insurance costs; solvent-based coatings evaporate during the drying process, which will make the filling effect of the coatings not very good, and the film formation will not be dense, which will affect the insulating coating. Insulation protection performance; and as people pay attention to environmental protection and health, "green ecology, resource protection" has become the main criterion for the selection of insulating coatings. Therefore, the current development of insulating coatings is mainly focused on environmentally friendly water-based insulating coatings.

The patent document whose publication number is CN105176344A discloses a water-based polyurethane insulating coating, which consists of: polyurethane A component, polyurethane B component, pigments and fillers, surface modifiers, deionized water; polyurethane A component It is a short-chain ether or alcohol-blocked isocyanate, which is used as a curing agent for water-based polyurethane insulating coatings. The polyurethane component B is a water-based flexible polyester resin. The surface modifier is a silane coupling agent. The pigment and filler have a layered structure. Among them, the weight ratio of the surface modifier to the pigment and filler is 1:100 to 3:100, and the weight ratio of the pigment and filler to the polyurethane B component modified by the surface modifier is 1:2 to 1: 4. The weight ratio of polyurethane A component to polyurethane B component is 1:2～1:4. The water-based polyurethane insulating paint prepared by the invention has strong adhesion, good stability, and excellent breakdown voltage resistance performance in specific applications. However, the above-mentioned water-based polyurethane coatings cannot be self-repaired, and the defects that are difficult to detect such as micro-damages and micro-cracks cannot be discovered and repaired in time, and there are potential hazards.

Contents of the invention

In view of this, the technical problem to be solved by the present invention is to provide a self-repairing insulating material for power equipment to improve the water resistance of the coating and to enable the coating to be repaired when cracks occur. Perform self-healing.

Another technical problem to be solved by the present invention is to provide a preparation method of a self-repairing insulating material used for electric equipment.

In order to solve the problems of the technologies described above, the technical solution adopted in the present invention is:

A self-repairing insulating material for power equipment, made of the following raw materials in parts by weight: 40-50 parts of water-based polyurethane-acrylate composite emulsion, 10-20 parts of self-repairing microcapsules, and 5-12 parts of surface modifier , 3-8 parts of nanoparticles, 10-20 parts of curing agent; wherein: the self-healing microcapsules are made of a capsule wall and a core material, the capsule wall is a modified urea-formaldehyde resin, and the core material is hexamethylene diisocyanate or isophorone diisocyanate.

As a further preferred solution, the preparation method of the self-healing microcapsules is as follows: mix the modified urea-formaldehyde resin prepolymer aqueous solution, hexamethylene diisocyanate and emulsifier, adjust the pH to below 3.0, stir and emulsify at a high speed, and the emulsion Under the condition of gas protection and stirring, the temperature is raised to 60-70°C to undergo polymerization reaction, and then cooled, filtered, washed and dried to obtain self-repairing microcapsules, the capsule wall is modified urea-formaldehyde resin, and the core material is hexamethylene Diisocyanate with a particle size of 50-400 microns and a wall thickness of 5-10 microns.

As a further preferred solution, the modified urea-formaldehyde resin is a resorcinol-modified urea-formaldehyde resin.

As a further preferred solution, the emulsifier is at least one of sodium dodecylbenzenesulfonate and styrene-maleic anhydride copolymer.

As a further preferred solution, the surface modifier is at least one of methacryloxypropyltrimethoxysilane, γ-aminopropyltriethoxysilane and titanate coupling agent.

As a further preferred solution, the nanoparticles are at least one of modified fumed silicon dioxide and modified nanometer ferric oxide.

As a further preferred solution, the curing agent is at least one of hexamethylene diisocyanate and isophorone diisocyanate.

The present invention also provides a preparation method for the above-mentioned self-repairing insulating material for electric equipment, comprising the following steps:

S1: Preparation of self-healing microcapsules;

S2: Provide water-based polyurethane-acrylate composite emulsion, surface modifier, nanoparticles and curing agent, mix the self-healing microcapsules with water-based polyurethane-acrylate composite emulsion, surface modifier, and nanoparticles, and stir evenly, Ultrasonic treatment to obtain a mixture;

S3: The mixture is mixed with a curing agent and left to stand to obtain a self-healing insulating material.

Compared with the prior art, the beneficial effects of the present invention are as follows:

1. The present invention uses water-based polyurethane-acrylate composite emulsion as the material matrix, and organically combines polyurethane and polyacrylate, which not only has the original superior performance of polyurethane, but also can increase the water resistance and UV aging resistance of the coating.

2. The present invention adopts the microcapsule self-repair technology to repair the cracks of the material, and pre-mixes the microcapsules containing the repair agent hexamethylene diisocyanate or isophorone diisocyanate into the coating. When the coating material is damaged , the microcapsules rupture and release the repairing agent. When the repairing agent encounters the matrix, a curing reaction occurs to repair the cracked surface and realize the self-repair of the damaged part.

3. A surface modifier is added to the material of the present invention, preferably at least one of methacryloxypropyltrimethoxysilane, γ-aminopropyltriethoxysilane and titanate coupling agent, using The surface group of the microcapsule itself is combined with one end of the surface modifier, and the other end of the surface modifier is combined with the active hydroxyl group of the water-based polyurethane-acrylate composite emulsion, so that the microcapsule can be tightly mixed with the matrix and enhance the coating. performance.

4. The present invention utilizes the in-situ polymerization method to prepare self-healing microcapsules. The modified urea-formaldehyde resin is used as the capsule wall, and hexamethylene diisocyanate or isophorone diisocyanate is used as the core material, which has good sealing performance. The process is simple, green and environmentally friendly. The prepared coating can realize self-healing, has solvent resistance and superhydrophobicity (contact angle is greater than 150°), and its hydrophobicity can be restored by itself many times, and has self-cleaning and antifouling effects. Under the accelerated aging tester and outdoor exposure, the contact angle of the coating increases with the aging time. After 72 hours of accelerated aging, the contact angle of the coating remains above 150°, which has continuous superhydrophobic performance and durability of the coating. good.

5. The coating of the present invention has good insulating properties. During the use of power equipment, due to the influence of the outside world and its own aging, the protective material of the shell will inevitably have micro-damages or micro-cracks, which are difficult to find with existing detection technologies, and these subtle detection tasks are usually not done . However, if the micro-damages or micro-cracks on these electrical equipment are not maintained for a long time, it will easily lead to a decline in its protective performance and affect the actual service life. The coating of the present invention self-repairs micro-damages or micro-cracks, has a high self-repair rate, and can obviously prolong its protective effect on equipment surfaces.

Detailed ways

In order to better understand the present invention, the content of the present invention is further clearly described below in conjunction with the examples, but the protection content of the present invention is not limited to the following examples. In the following description, numerous specific details are given in order to provide a more thorough understanding of the present invention. It will be apparent, however, to one skilled in the art that the present invention may be practiced without one or more of these details.

Unless otherwise specified, all raw materials are derived from commercially available products, and unless otherwise specified, do not contain other unspecified components except unavoidable impurities.

In the following examples, the water-based polyurethane-acrylate composite emulsion refers to the literature (: Hu Guowen, Shen Huifang, Yang Qingfeng, etc. Synthesis and characterization of polyurethane-acrylate composite emulsion [J]. Journal of South China University of Technology: Natural Science Edition, 2007 , 35(6):7.DOI:10.3321/j.issn:1000-565X.2007.06.014.) was synthesized by the method described in, and room temperature crosslinking type PUA-3 waterborne polyurethane-acrylate composite emulsion was obtained.

The preparation method of modified fumed silica adopts the following steps: mix ethanol and tridecafluorooctyltrimethoxysilane, stir evenly, then add fumed silica and ammonia water, after ultrasonic treatment, stir and react at 65°C for 20h, A modified nano-silica solution is obtained; ethanol in the modified nano-silica solution is removed by rotary evaporation, dried and ground to obtain modified fumed silica.

The consumption of the above-mentioned ethanol is 25 times of the quality of fumed silica; the consumption of tridecafluorooctyltrimethoxysilane is 0.3 times of the quality of fumed silica; the consumption of ammonia water is 0.2 times of the quality of fumed silica; The power is 200W, and the time is 5min.

The preparation method of the modified nano ferric oxide refers to the modified fumed silica.

The following are specific test cases.

Example 1

A self-repairing insulating material for power equipment, made of the following raw materials in parts by weight: 45 parts of water-based polyurethane-acrylate composite emulsion, 15 parts of self-repairing microcapsules, 8 parts of surface modifiers, 5 parts of nanoparticles, 15 parts of curing agent; wherein: self-healing microcapsules are made of capsule wall and core material, the capsule wall is modified urea-formaldehyde resin, and the core material is hexamethylene diisocyanate.

The modified urea-formaldehyde resin is a resorcinol-modified urea-formaldehyde resin.

The preparation method of self-healing microcapsules is as follows: mix the modified urea-formaldehyde resin prepolymer aqueous solution, hexamethylene diisocyanate and emulsifier, adjust the pH to 3.0, stir and emulsify at high speed, and heat up the emulsion under gas protection and stirring conditions Polymerization reaction occurs at 65°C, then cooling, suction filtration, washing and drying to obtain self-repairing microcapsules, the capsule wall is modified urea-formaldehyde resin, the core material is hexamethylene diisocyanate, and the particle size is 50-400 microns. The wall thickness is 5-10 microns.

The mass ratio of the modified urea-formaldehyde resin prepolymer aqueous solution, hexamethylene diisocyanate and emulsifier is 1:0.4:0.2; the emulsifier is styrene-maleic anhydride copolymer.

The modified urea-formaldehyde resin prepolymer aqueous solution is prepared by the following method: mix urea, formaldehyde, resorcinol and deionized water, adjust the pH to 8.0, raise the temperature to 75°C, and stir for 1 hour to obtain the modified urea-formaldehyde resin prepolymer aqueous solution.

The mass ratio of the above urea to formaldehyde is 1:2; the mass ratio of resorcinol to urea is 0.3:1.

The surface modifier is methacryloxypropyltrimethoxysilane.

The nanoparticles are modified fumed silica.

The curing agent is hexamethylene diisocyanate.

The preparation method of the above-mentioned self-repairing insulating material for electric equipment comprises the following steps:

S1: Preparation of self-healing microcapsules;

S2: Provide water-based polyurethane-acrylate composite emulsion, surface modifier, nanoparticles and curing agent, mix self-healing microcapsules with water-based polyurethane-acrylate composite emulsion, surface modifier, and nanoparticles, stir evenly, and perform ultrasonic treatment , to get a mixture;

S3: mixing the mixture with a curing agent and standing still to obtain a self-healing insulating material.

The process steps of ultrasonic treatment include: power 200W, time 30min.

Example 2

A self-repairing insulating material for power equipment, made of the following raw materials in parts by weight: 40 parts of water-based polyurethane-acrylate composite emulsion, 10 parts of self-repairing microcapsules, 5 parts of surface modifiers, 3 parts of nanoparticles, 10 parts of curing agent; wherein: the self-healing microcapsules are made of a capsule wall and a core material, the capsule wall is a modified urea-formaldehyde resin, and the core material is isophorone diisocyanate.

The modified urea-formaldehyde resin is a resorcinol-modified urea-formaldehyde resin.

The preparation method of self-healing microcapsules is as follows: Mix the aqueous solution of modified urea-formaldehyde resin prepolymer, hexamethylene diisocyanate and emulsifier, adjust the pH to 2.5, emulsify with high-speed stirring, and heat up the emulsion under gas protection and stirring conditions Polymerization reaction occurs at 60°C, then cooling, suction filtration, washing and drying to obtain self-repairing microcapsules, the capsule wall is modified urea-formaldehyde resin, the core material is hexamethylene diisocyanate, and the particle size is 50-400 microns. The wall thickness is 5-10 microns.

The mass ratio of the modified urea-formaldehyde resin prepolymer aqueous solution, hexamethylene diisocyanate and emulsifier is 1:0.4:0.2; the emulsifier is sodium dodecylbenzenesulfonate.

The modified urea-formaldehyde resin prepolymer aqueous solution is prepared by the following method: mix urea, formaldehyde, resorcinol and deionized water, adjust the pH to 8.0, raise the temperature to 75°C, and stir for 1 hour to obtain the modified urea-formaldehyde resin prepolymer aqueous solution.

The mass ratio of the above urea to formaldehyde is 1:2; the mass ratio of resorcinol to urea is 0.3:1.

The surface modifier is γ-aminopropyltriethoxysilane.

The nanoparticles are modified fumed silica.

The curing agent is isophorone diisocyanate.

The preparation method of the above-mentioned self-repairing insulating material for electric equipment comprises the following steps:

S1: Preparation of self-healing microcapsules;

S2: Provide water-based polyurethane-acrylate composite emulsion, surface modifier, nanoparticles and curing agent, mix self-healing microcapsules with water-based polyurethane-acrylate composite emulsion, surface modifier, and nanoparticles, stir evenly, and perform ultrasonic treatment , to get a mixture;

S3: mixing the mixture with a curing agent and standing still to obtain a self-healing insulating material.

The process steps of ultrasonic treatment include: power 300W, time 25min.

Example 3

A self-repairing insulating material for power equipment, made of the following raw materials in parts by weight: 50 parts of water-based polyurethane-acrylate composite emulsion, 20 parts of self-repairing microcapsules, 12 parts of surface modifier, 8 parts of nanoparticles, 20 parts of curing agent; wherein: the self-healing microcapsules are made of a capsule wall and a core material, the capsule wall is a modified urea-formaldehyde resin, and the core material is hexamethylene diisocyanate.

The modified urea-formaldehyde resin is a resorcinol-modified urea-formaldehyde resin.

The preparation method of self-healing microcapsules is as follows: mix the modified urea-formaldehyde resin prepolymer aqueous solution, hexamethylene diisocyanate and emulsifier, adjust the pH to 2.3, stir and emulsify at a high speed, and heat up the emulsion under gas protection and stirring conditions Polymerization reaction occurs at 70°C, then cooling, suction filtration, washing and drying to obtain self-repairing microcapsules, the capsule wall is modified urea-formaldehyde resin, the core material is hexamethylene diisocyanate, and the particle size is 50-400 microns. The wall thickness is 5-10 microns.

The mass ratio of the modified urea-formaldehyde resin prepolymer aqueous solution, hexamethylene diisocyanate and emulsifier is 1:0.4:0.2; the emulsifier is styrene-maleic anhydride copolymer.

The modified urea-formaldehyde resin prepolymer aqueous solution is prepared by the following method: mix urea, formaldehyde, resorcinol and deionized water, adjust the pH to 8.0, raise the temperature to 75°C, and stir for 1 hour to obtain the modified urea-formaldehyde resin prepolymer aqueous solution.

The mass ratio of the above urea to formaldehyde is 1:2; the mass ratio of resorcinol to urea is 0.3:1.

The surface modifier is titanate coupling agent 201.

The nanoparticles are modified nano ferric oxide.

The curing agent is hexamethylene diisocyanate.

The preparation method of the above-mentioned self-repairing insulating material for electric equipment comprises the following steps:

S1: Preparation of self-healing microcapsules;

S2: Provide water-based polyurethane-acrylate composite emulsion, surface modifier, nanoparticles and curing agent, mix self-healing microcapsules with water-based polyurethane-acrylate composite emulsion, surface modifier, and nanoparticles, stir evenly, and perform ultrasonic treatment , to get a mixture;

S3: mixing the mixture with a curing agent and standing still to obtain a self-healing insulating material.

The process steps of ultrasonic treatment include: power 400W, time 20min.

The following is a comparison test case.

Comparative Example 1: An insulating material for electric equipment, made of the following raw materials in parts by weight: 45 parts of water-based polyurethane-acrylate composite emulsion, 10 parts of resorcinol-modified urea-formaldehyde resin, methacryloxy 8 parts of propyltrimethoxysilane, 5 parts of modified fumed silica, and 20 parts of hexamethylene diisocyanate.

The preparation method of the insulating material is: mixing water-based polyurethane-acrylate composite emulsion, resorcinol-modified urea-formaldehyde resin, methacryloxypropyl trimethoxysilane, and modified fumed silica, stirring evenly, The power is 200W, and the time is 30 minutes for ultrasonic treatment to obtain a mixture; the mixture is mixed with a curing agent and left to stand to obtain an insulating material.

Comparative Example 2: Different from Example 1, the preparation method of self-healing microcapsules is as follows: Mix the aqueous solution of modified urea-formaldehyde resin prepolymer, hexamethylene diisocyanate and emulsifier, adjust the pH to 5.5, and emulsify with high-speed stirring , under the condition of gas protection and stirring, the temperature of the emulsion is raised to 80° C. to undergo a polymerization reaction, and then cooled, suction filtered, washed and dried to obtain self-healing microcapsules.

The mass ratio of the modified urea-formaldehyde resin prepolymer aqueous solution, hexamethylene diisocyanate and emulsifier is 1:1:0.2; the emulsifier is styrene-maleic anhydride copolymer.

Comparative Example 3: The difference from Example 1 is that the nanoparticles use fumed silica instead of modified fumed silica.

Comparative Example 4: The difference from Example 1 is that the material is made of the following raw materials in parts by weight: 45 parts of water-based polyurethane-acrylate composite emulsion, 30 parts of self-repairing microcapsules, 15 parts of surface modifier, and 10 parts of nanoparticles , 20 parts of curing agent.

The materials prepared in the above-mentioned Examples 1-3 and Comparative Examples 1-4 were respectively coated on stainless steel plates with a thickness of 0.5 cm, a length of 10 cm, and a width of 8 cm, and conformed to the power grid equipment specifications, and the coating thickness was 200 Micron, make a test sample, and perform the following performance tests after the coating is cured, including:

1. Determination of the contact angle of the coating surface: using the pendant drop method, put 2 μL of deionized water on the coating surface, select 5 points for each sample to measure, and take the average value of the final results.

2. Aging resistance of the coating: put the test sample in a UV aging box, the UV lamp used in the aging box has a wavelength of 310nm, and the accelerated aging conditions are: 60°C, 4 hours of UV light, and 0.71W/ ^m2 of light intensity; Condensate and reflux at 50°C for 4 hours, repeat 9 cycles, and measure the contact angle of the coating surface.

3. Repair characterization: Draw cracks with the same length and width on the coating surface, record the length and width of the cracks in each test sample, observe the repair status of the cracks after 4 hours, and calculate the repair efficiency. Repair efficiency = (crack area before repair - crack area after repair) / crack area before repair × 100%.

The above data show that the coating of the present invention has a contact angle of greater than 150°, which is superhydrophobic; after 72h aging resistance test, the contact angle does not change significantly, still greater than 150°, and the superhydrophobicity has good persistence. It has good aging resistance; at the same time, it also has outstanding crack repair ability, and can repair more than 70% of cracks in a short period of time.

The coating prepared in Comparative Example 1 basically has no self-healing ability. Although it basically contains all raw materials, no self-healing capsule is used, and the self-crosslinking curing ability cannot be stimulated under crack conditions.

In Comparative Example 2, the preparation process of the self-healing capsule was changed, and the self-healing ability of the coating prepared by using it decreased significantly.

In Comparative Example 3, nanoparticles were used instead of modified nanoparticles, and the hydrophobicity of the resulting coating decreased, the uniformity of the coating was average, and the stability was poor.

In Comparative Example 4, the ratio of each raw material was adjusted, and the contact angle of the obtained coating became smaller, the hydrophobicity decreased, and the repairing ability decreased at the same time.

The above test examples show that the various raw materials in the insulating material of the present invention cooperate with each other to obtain an insulating protective coating with superhydrophobicity, aging resistance and self-repairing ability.

Finally, it is noted that the above embodiments are only used to illustrate the technical solution of the present invention without limitation, other modifications or equivalent replacements made by those skilled in the art to the technical solution of the present invention, as long as they do not depart from the spirit and spirit of the technical solution of the present invention All should be included in the scope of the claims of the present invention.

Claims (8)

1. A self-repairing insulating material for power equipment, characterized in that: it is made of the following raw materials in parts by weight: 40-50 parts of water-based polyurethane-acrylate composite emulsion, 10-20 parts of self-repairing microcapsules, surface modification 5-12 parts of active agent, 3-8 parts of nanoparticles, and 10-20 parts of curing agent; wherein: the self-healing microcapsules are made of capsule wall and core material, the capsule wall is modified urea-formaldehyde resin, and the The core material is hexamethylene diisocyanate or isophorone diisocyanate. 2. A kind of self-repairing insulating material for electric equipment as claimed in claim 1, is characterized in that: the preparation method of described self-repairing microcapsule is as follows: the modified urea-formaldehyde resin prepolymer aqueous solution, hexamethylene Mix diisocyanate and emulsifier, adjust the pH to below 3.0, stir and emulsify at high speed, heat the emulsion to 60-70°C under the condition of gas protection and stirring to undergo polymerization reaction, then cool, filter, wash and dry to obtain self-healing In the microcapsule, the capsule wall is modified urea-formaldehyde resin, the core material is hexamethylene diisocyanate, the particle diameter is 50-400 microns, and the wall thickness is 5-10 microns. 3. A self-repairing insulating material for power equipment according to claim 1, characterized in that: the modified urea-formaldehyde resin is a resorcinol-modified urea-formaldehyde resin. 4. A kind of self-repairing insulation material for power equipment as claimed in claim 2, is characterized in that: described emulsifier is sodium dodecylbenzene sulfonate and at least one of styrene-maleic anhydride copolymer kind. 5. A self-repairing insulating material for power equipment as claimed in claim 1, wherein said surface modifier is methacryloxypropyltrimethoxysilane, γ-aminopropyl At least one of triethoxysilane and titanate coupling agent. 6 . The self-repairing insulating material for power equipment according to claim 1 , wherein the nano-particles are at least one of modified fumed silica and modified nano-ferric oxide. 7 . 7. The self-repairing insulating material for power equipment according to claim 1, wherein the curing agent is at least one of hexamethylene diisocyanate and isophorone diisocyanate. 8. A method for preparing a self-repairing insulating material for power equipment as claimed in claim 1, characterized in that: comprising the following steps: S1: Preparation of self-healing microcapsules; S2: Provide water-based polyurethane-acrylate composite emulsion, surface modifier, nanoparticles and curing agent, mix the self-healing microcapsules with water-based polyurethane-acrylate composite emulsion, surface modifier, and nanoparticles, and stir evenly, Ultrasonic treatment to obtain a mixture; S3: The mixture is mixed with a curing agent and left to stand to obtain a self-healing insulating material.