CN110776813A - VPI-based insulating impregnating varnish and insulating treatment method of electrical product - Google Patents

VPI-based insulating impregnating varnish and insulating treatment method of electrical product Download PDF

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CN110776813A
CN110776813A CN201910898277.3A CN201910898277A CN110776813A CN 110776813 A CN110776813 A CN 110776813A CN 201910898277 A CN201910898277 A CN 201910898277A CN 110776813 A CN110776813 A CN 110776813A
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core
impregnating varnish
vpi
parts
shell
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狄宁宇
陆云峰
虞希高
曹万荣
凌斌
许坤
王文佳
程微
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Zhejiang Bo Fei Electric Ltd By Share Ltd
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    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D167/00—Coating compositions based on polyesters obtained by reactions forming a carboxylic ester link in the main chain; Coating compositions based on derivatives of such polymers
    • C09D167/06—Unsaturated polyesters having carbon-to-carbon unsaturation
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D5/00—Processes for applying liquids or other fluent materials to surfaces to obtain special surface effects, finishes or structures
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D7/00—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials
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    • C09D5/00—Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced; Filling pastes
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    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
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    • C09K5/00—Heat-transfer, heat-exchange or heat-storage materials, e.g. refrigerants; Materials for the production of heat or cold by chemical reactions other than by combustion
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    • C09K5/14—Solid materials, e.g. powdery or granular
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    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
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    • C08K2201/011—Nanostructured additives
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    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L2205/00—Polymer mixtures characterised by other features
    • C08L2205/03—Polymer mixtures characterised by other features containing three or more polymers in a blend

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  • Inorganic Chemistry (AREA)
  • Insulation, Fastening Of Motor, Generator Windings (AREA)

Abstract

The application discloses insulating impregnating varnish based on VPI and an insulating treatment method of an electrical product, wherein the insulating impregnating varnish comprises the following raw materials in parts by mass: core-shell structured nanoparticles: 10-40 parts; matrix resin: 100-130 parts; curing agent: 1-9 parts; diluent agent: 20-50 parts of a solvent; accelerator (b): 0.5-3.5 parts; initiator: 0.5 to 3.5 portions. The VPI-based insulating impregnating varnish can improve the thermal conductivity of an insulating material through curing; meanwhile, the thermal stress generated by the insulating material during temperature change can be reduced.

Description

VPI-based insulating impregnating varnish and insulating treatment method of electrical product
Technical Field
The application relates to the technical field of electrical product insulation treatment, in particular to VPI-based insulation impregnating varnish and an electrical product insulation treatment method.
Background
The insulating impregnating varnish is one of the main insulating materials for the winding insulation of electrical products, and through the impregnating process, the varnish liquid quickly permeates into gaps and air holes of coils, wire grooves or other insulators, and forms a heat-conducting insulating whole with the coils, wires and the like after curing.
The heat-conducting and insulating polymer material is divided into a body type and a filling type. The bulk heat-conducting insulating polymer material obtains heat-conducting insulating performance by changing an aggregation structure or a polymer chain structure in the processes of synthesis and molding. The heat-conducting insulating polymer prepared by the method has high cost and complex synthesis process. The filling type heat conduction and insulation composite material is a composite material with better heat conduction and insulation performance obtained by filling heat conduction and insulation inorganic particles such as SiC, AlN and the like in a polymer and replacing a relatively disordered lattice structure material (low-heat-conductivity epoxy) with an ordered lattice structure material (high-heat-conductivity SiC and the like), and becomes a heat conduction and insulation material widely used at present.
At present, the insulation impregnating varnish for electrical products (such as wind power products) forms two systems of a modified unsaturated polyester resin + reactive diluent system and a high-purity epoxy + liquid anhydride system. The mechanism of the resin curing reaction shows that the insulating impregnating varnish often has cracking phenomenon due to the internal stress in the cured product, thereby causing potential safety hazard.
Disclosure of Invention
Aiming at the problems in the prior art, the insulating impregnating varnish based on VPI is provided, and the insulating impregnating varnish can improve the thermal conductivity of an insulating material through curing; meanwhile, the thermal stress generated by the insulating material during temperature change can be reduced.
The application provides insulating impregnating varnish based on VPI, by mass portion, insulating impregnating varnish's raw materials includes:
Figure BDA0002210983830000021
the nano-particles with the core-shell structure take a resin material as a shell and an energy storage material as a core.
Several alternatives are provided below, but not as an additional limitation to the above general solution, but merely as a further addition or preference, each alternative being combinable individually for the above general solution or among several alternatives without technical or logical contradictions.
Preferably, the resin material is selected from one or more of graphene oxide-epoxy resin composite and graphene oxide-soluble polyimide composite; the energy storage material is selected from one or more of inorganic phase change energy storage materials, organic phase change energy storage materials and composite phase change energy storage materials.
Preferably, the energy storage material is selected from one or more of polyethylene glycol, paraffin, polyethylene oxide, polyethylene wax, pentaerythritol, high density polyethylene, polyamide, trimethylolethane, neopentyl glycol, trimethylolpropane.
Preferably, the phase transition temperature of the energy storage material is 20-200 ℃.
Preferably, the core of the nanoparticle with the core-shell structure is a single-layer core, and the using amount ratio of the core material to the shell material is 1: 3.3 to 3.5.
Preferably, the core of the nanoparticle with the core-shell structure is a double-layer core, and the using amount ratio of the core material to the shell material is 1: 1.6-1.8, wherein the dosage ratio of the outer layer material of the core to the inner layer material of the core is 1:2.0 to 2.2.
Preferably, the VPI-based insulating impregnating varnish comprises the following raw materials in parts by mass:
Figure BDA0002210983830000031
preferably, the matrix resin includes, in parts by mass:
60-70 parts of unsaturated polyester;
45-55 parts of novolac epoxy.
Preferably, the curing agent is tung oil anhydride, the initiator is dicumyl peroxide, the accelerator is cobalt naphthenate, and the diluent is trimethylolpropane triacrylate.
Preferably, the VPI-based insulating impregnating varnish comprises the following raw materials in parts by mass:
Figure BDA0002210983830000032
the shell of the nano-particles with the core-shell structure is a graphene oxide-epoxy resin compound; the core of the nanoparticle with the core-shell structure is pentaerythritol and neopentyl glycol.
The application also provides an insulation treatment method of the electrical product, the VPI-based insulation impregnating varnish is used for impregnating the electrical product, pre-curing is carried out for 4-5 h at the temperature of 140-150 ℃ after impregnation, and then re-curing is carried out for 7-8 h at the temperature of 170-180 ℃ to complete the insulation treatment.
The insulating impregnating varnish disclosed by the invention uses the core-shell structured nanoparticles as the filler, so that the thermal expansion coefficient of the insulating impregnating varnish can be reduced, the highest heat release temperature of the insulating impregnating varnish is inhibited, the heat conductivity and the size stability after curing of the insulating impregnating varnish are improved, and the thermal stress generated by resin in the temperature change process is reduced.
Detailed Description
The present application is further illustrated by the following examples.
One embodiment of the application provides an insulating impregnating varnish based on VPI, and the insulating impregnating varnish comprises the following raw materials in parts by mass: core-shell structured nanoparticles: 10-40 parts; matrix resin: 100-130 parts; curing agent: 1-9 parts; diluent agent: 20-50 parts of a solvent; accelerator (b): 0.5-3.5 parts; initiator: 0.5-3.5 parts;
the nano-particles with the core-shell structure take a resin material as a shell and an energy storage material as a core.
Research shows that internal stress exists in a cured product formed after the impregnating varnish is cured, the internal stress is also a main cause of cracking, and the sources of the internal stress are two:
firstly, shrinkage stress due to volume shrinkage during curing;
secondly, the epoxy resin is heated due to curing heating, and is heated after curing, and the epoxy resin is caused by thermal stress generated when the temperature changes due to the difference of the expansion coefficients of the cured epoxy resin and the metal.
In particular, by combining a specific matrix resin composition, the difference in expansion coefficient between a cured product and a metal can be reduced, the maximum exothermic temperature can be suppressed, and the purpose of reducing shrinkage stress and avoiding cracking can be achieved.
The nano-particles with the core-shell structure take a resin material as a shell and an energy storage material as a core; the shell has a hollow structure, and the core is wrapped in the shell, so that the energy storage material serving as the core is prevented from leaking when solid-liquid phase conversion occurs. In addition, the nano particles with the core-shell structure also have insulativity and thermal conductivity, and can be regarded as insulating filler and thermal conductive filler.
As for the resin material itself as the shell, the prior art may be adopted, but preferred embodiments are also provided herein, for example, the resin material is selected from one or more of graphene oxide-epoxy resin composite, graphene oxide-soluble polyimide composite; suitable shell-core material combinations are advantageous to further suppress peak exotherm temperatures.
The energy storage material as the core is selected from one or more of phase change energy storage materials, such as one or more of inorganic phase change energy storage materials, organic phase change energy storage materials and composite phase change energy storage materials. In a more preferred embodiment the phase change energy storage material is selected from one or more of polyethylene glycol (PEG), paraffin wax, polyethylene oxide (PEO), PE wax, Pentaerythritol (PE), High Density Polyethylene (HDPE), Polyamide (PA), trimethylolethane (PG), neopentyl glycol (NPG), Trimethylolpropane (TMP).
The core of the core-shell structure nanoparticle can be a single-layer core or a double-layer core, one or more phase change energy storage materials can be adopted for a certain layer, when multiple phase change energy storage materials are adopted, in a preferred embodiment, the single-layer core material of the core-shell structure nanoparticle is preferably a composite material of PE and NPG, and the dosage ratio of the PE to the NPG is 1: 2.0-2.2 in parts by mass.
In a further preferred embodiment, the amount ratio of PE to NPG is 2.0 parts by mass.
In a preferred embodiment, for the nanoparticles of the core-shell structure with a single-layer core, the ratio of the core material to the shell material of the nanoparticles of the core-shell structure is 1: 3.3 to 3.5.
In a further preferred embodiment, the ratio of the core material to the shell material of the core-shell structured nanoparticles is 1: 3.4.
in a preferred embodiment, the double-layer core material of the core-shell structured nanoparticle is preferably PG as the outer layer material of the core; the PE and NPG composite serves as the inner layer material of the core. The usage ratio of the outer layer material of the core to the inner layer material of the core is 1:2.0 to 2.2; the dosage ratio of PE and NPG of the inner layer material is 1: 3.0-3.2.
In a further preferred embodiment, the ratio of the amount of the outer layer material of the core to the amount of the inner layer material of the core is 1: 2.0; the dosage ratio of PE and NPG of the inner layer material is 1: 3.0.
In a preferred embodiment, for the nanoparticle having a core-shell structure with a double-layer core, the ratio of the core material to the shell material in the nanoparticle having a core-shell structure is 1: 1.6 to 1.8.
In a further preferred embodiment, the ratio of the core material to the shell material of the core-shell structured nanoparticles is 1: 1.7.
the selection of the phase change energy storage material is, on the one hand, the phase change temperature of the phase change energy storage material is considered, and in the application, in combination with a corresponding use scenario, in a preferred embodiment, the phase change temperature of the energy storage material is 20 ℃ to 200 ℃.
In a further preferred embodiment, the phase transition temperature of the energy storage material is between 50 ℃ and 180 ℃.
In combination with corresponding usage scenarios, for example, the stator insulation heat resistance grades of both the direct-drive and the doubly-fed generator are F or H grade, and the internal temperature during the operation of the motor is between 60 ℃ and 120 ℃, so that in a further preferred embodiment the phase transition temperature of the energy storage material is between 60 ℃ and 120 ℃.
Furthermore, phase change materials with melting temperatures above 180 ℃ may contribute to a reduction in the temperature peak during operation of the device, and therefore the melting temperature of the energy storage material is preferably above 180 ℃, for example the melting temperature of the energy storage material is between 180 ℃ and 260 ℃.
Current solid-liquid phase change energy storage materials, whether inorganic or organic, have a liquid phase generated during the phase change process and must be encapsulated.
The packaging process may be carried out by one or more of physical pulverization, construction, sol-gel, electric spraying, freeze drying, and template removal.
In a preferred embodiment, the core-shell structured nanoparticles are prepared by a coaxial high-voltage electrostatic spraying method. The method takes the phase-change energy storage material as a core and the coating material (resin material) as a shell to prepare the nano-particles with the core-shell structure, and can solve the problem of leakage of the phase-change energy storage material in the phase-change process.
The VPI-based insulating impregnating varnish can be obtained by mixing the core-shell structure nanoparticles with corresponding matrix resin, curing agent, diluent, accelerator and initiator.
In a preferred embodiment, the VPI-based insulating impregnating varnish comprises, in parts by mass, the following raw materials:
core-shell structured nanoparticles: 15-35 parts; matrix resin: 105-125 parts; curing agent: 2-8 parts; diluent agent: 25-45 parts of a solvent; accelerator (b): 1-3 parts; initiator: 1-3 parts.
In a further preferred embodiment, the VPI-based insulating impregnating varnish comprises, in parts by mass, the following raw materials:
core-shell structured nanoparticles: 20-30 parts of a solvent; matrix resin: 110-120 parts; curing agent: 3-6 parts; diluent agent: 30-40 parts of a binder; accelerator (b): 1.5-2.5 parts; initiator: 1.5 to 2.5 portions.
The better performance can be obtained by further optimizing the dosage of the matrix resin, and the epoxy resin and the unsaturated resin are selected as the matrix resin according to the characteristics of the epoxy resin and the unsaturated resin, so that the strength of the product after curing can be improved, and the shrinkage rate can be reduced. Meanwhile, the viscosity of the matrix resin is high, the use of the insulating impregnating varnish is influenced by the viscosity, and a diluent is required to be added to reduce the viscosity.
In order to further exert the synergy with the nanoparticle filler, the matrix resin is selected from a mixed system of unsaturated polyester and novolac epoxy, and in a preferred embodiment, the matrix resin comprises the following components in parts by mass: unsaturated polyester: 60-70 parts; phenol-formaldehyde epoxy: 45-55 parts.
In terms of unsaturated polyester and novolac epoxy per se, and without emphasis on the improvement of the present application, commercially available products can be selected, for example, E-44 epoxy resin, E-12 epoxy resin, and No. 607 epoxy resin can be selected as novolac epoxy; FX-996A unsaturated resin and FX-997C unsaturated resin can be selected as the unsaturated polyester, and the selection can enable the electrical performance and the heat resistance grade of the VPI-based insulating impregnating varnish to meet the requirements of electrical insulating materials.
In a further preferred embodiment, the base resin comprises, in parts by mass: unsaturated polyester: 63-67 parts; phenol-formaldehyde epoxy: 47-53 parts.
When the proportion of the matrix resin is selected, in order to enable the unsaturated polyester and the novolac epoxy to exert better performance, the practical application finds that the unsaturated polyester and the novolac epoxy are further optimized, so that the unsaturated polyester and the novolac epoxy are better in compatibility, and the VPI-based insulating impregnating varnish is favorable for obtaining better bonding strength and shrinkage performance.
Although the types of diluents which can be matched with unsaturated polyester and novolac epoxy in the prior art are more, in combination with the physicochemical properties of the nanoparticles, the application provides a preferred diluent in one embodiment, which is more favorable for the preparation, drying and improvement of the performance of the insulation impregnating varnish after curing, and the preferred diluent is trimethylolpropane triacrylate.
In addition, by combining the characteristics of the unsaturated polyester and the novolac epoxy, a curing agent, an accelerator and an initiator can be selected correspondingly, and a further improved scheme is provided correspondingly in the application and corresponding beneficial effects are obtained. The specific combination and proportion relationship of the three components form an initiating system with better effect.
Because the VPI-based insulating impregnating varnish has more choices of components and proportions and the core-shell structured nanoparticles, in a further preferred embodiment, the VPI-based insulating impregnating varnish comprises the following raw materials in parts by mass:
20-30 parts of core-shell structure nanoparticles; 63-67 parts of unsaturated polyester; 47-53 parts of novolac epoxy; 3-6 parts of tung oil anhydride; 30-40 parts of trimethylolpropane triacrylate; 1.5-2.5 parts of cobalt naphthenate; 1.5-2.5 parts of dicumyl peroxide; the shell of the nano-particle with the core-shell structure is a graphene oxide-epoxy resin compound, and the core is pentaerythritol and neopentyl glycol.
An embodiment of the present application further provides an insulation treatment method for an electrical product, where the electrical product may refer to a common motor component, and in the insulation treatment method of this embodiment, an insulation impregnating varnish defined in each of the above embodiments or a combination of a plurality of embodiments may be selected, and in a specific implementation, the VPI-based insulation impregnating varnish of at least one embodiment of the present application is first used to impregnate the electrical product, and after impregnation, the electrical product is pre-cured at 140 ℃ to 150 ℃ for 4 to 5 hours, and then cured at 170 ℃ to 180 ℃ for 7 to 8 hours to complete the insulation treatment.
Because the VPI-based insulating impregnating varnish disclosed by the application is added with the core-shell structure nanoparticles, and the core material is the phase-change energy storage material, the curing in the application is divided into two stages, and the temperatures of the two stages are slightly different. Thus, the insulating impregnating varnish can be heated more uniformly by adopting a gradient temperature rise method.
Various embodiments of the present application are provided below.
Preparation example 1
Preparation of the shell: 10g of soluble thermoplastic Polyimide (PI) powder and 50ml of Dimethylacetamide (DMAC) solvent are placed in a reaction vessel and stirred at room temperature (for example, by a magnetic stirrer) until the powder is completely dissolved, thus obtaining a polyimide solution. Placing 0.2g of Graphene Oxide (GO) and 50ml of Dimethylacetamide (DMAC) solvent in a reaction container, and uniformly dispersing the Graphene Oxide (GO) (for example, by using ultrasonic waves) to obtain a graphene oxide solution. And (3) uniformly mixing the polyimide solution and the graphene oxide solution (for example, by using a magnetic stirrer) to obtain a PI-GO solution.
Preparation of the core: 2g of neopentyl glycol (NPG), 25ml of acetone and 1g of pentaerythritol were charged into a reaction vessel and dissolved to obtain a NPG-PE solution.
The preparation method of the nano-particles comprises the following steps: and (3) taking the PI-GO solution as a shell solution and the NPG-PE solution as a core solution, adjusting the voltage to 18-22 kV, adjusting the distance to 15cm, controlling the outer core sample injection speed to be 1ml/h and the inner core sample injection speed to be 0.5ml/h, and performing electric spraying to obtain the nano-particles with the core-shell structure.
Preparation example 2
The shell was prepared as in preparation example 1.
The preparation method of the core comprises the following steps: 3g of neopentyl glycol (NPG), 25ml of acetone and 1g of pentaerythritol were charged into a reaction vessel and dissolved to obtain a NPG-PE solution. 2g of trimethylolethane (PG) was dissolved in 20ml of anhydrous ethanol to obtain a PG solution.
Preparing nano particles: in the embodiment, a three-layer coaxial electrospraying method is adopted for preparing the nanoparticles, namely, a PI-GO solution is used as a canopy solution, a PG solution is used as a shell solution, an NPG-PE solution is used as a core solution, the voltage is adjusted to 18-22 kV, the distance is 15cm, the sampling speed of the canopy is 1ml/h, the sampling speed of the shell is 0.8ml/h, the sampling speed of the core is 0.5ml/h, and the nanoparticles with the core-shell structure are obtained by electrospraying.
Preparation example 3
Preparation of the shell: placing 0.2g of Graphene Oxide (GO) and 25ml of acetone solvent in a reaction vessel, and uniformly dispersing the Graphene Oxide (GO) (for example, by using ultrasonic waves) to obtain a graphene oxide solution. 10g of E03 epoxy resin and 25ml of acetone solvent are placed in a reaction vessel, so that E03 epoxy resin is completely dissolved, and an epoxy resin solution is obtained. And (3) uniformly mixing the epoxy resin solution and the graphene oxide solution (for example, adopting a magnetic stirrer) to obtain a GO-epoxy resin solution with the concentration of 20%, and standing for defoaming.
Preparation of the core: 2g of neopentyl glycol (NPG), 25ml of acetone and 1g of pentaerythritol were charged into a reaction vessel and dissolved to obtain a NPG-PE solution.
Preparing nano particles: and (2) taking the GO-epoxy resin solution as a shell solution and the NPG-PE solution as a core solution, adjusting the voltage to 18-22 kV, adjusting the distance to 15cm, controlling the outer core sample injection speed to be 2ml/h and the inner core sample injection speed to be 0.8ml/h, and performing electric injection to obtain the nano-particles with the core-shell structure.
Example 1
In this example, the core-shell structured nanoparticles obtained in preparation example 1 were mixed with other raw materials to obtain a VPI-based insulating impregnating varnish, and the raw materials include, in parts by mass:
Figure BDA0002210983830000091
example 2
In this example, the core-shell structured nanoparticles obtained in preparation example 1 were mixed with other raw materials to obtain a VPI-based insulating impregnating varnish, and the raw materials include, in parts by mass:
Figure BDA0002210983830000092
example 3
In this example, the core-shell structured nanoparticles obtained in preparation example 2 were mixed with other raw materials to obtain a VPI-based insulating impregnating varnish, and the raw materials include, in parts by mass:
example 4
In this example, the nanoparticle with the core-shell structure obtained in preparation example 3 is mixed with other raw materials to obtain the VPI-based insulating impregnating varnish, and the raw materials include, by mass:
Figure BDA0002210983830000111
examples 5 to 10
In examples 5 to 10, the raw materials include (in terms of mass parts):
example 5 Example 6 Example 7 Example 8 Example 9 Example 10
Core-shell structured nanoparticles 10 40 15 35 20 30
Unsaturated polyester 50 70 60 70 63 67
Novolac epoxy 50 60 45 55 47 53
Tung oil anhydride 1 9 2 8 3 6
Dicumyl peroxide 20 50 25 45 30 40
Cobalt naphthenate 0.5 3.5 1 3 1.5 2.5
Trimethylolpropane triacrylate 0.5 3.5 1 3 1.5 2.5
In examples 5 to 10, the core-shell structured nanoparticles obtained in preparation example 1 were used.
Example 11
In this embodiment, an electrical product (for example, a motor winding or the like) to be subjected to insulation treatment is pre-baked to remove moisture, then cooled, and then placed in a vacuum environment, air and volatile matters in the coil are removed, and the electrical product is fully immersed in the insulation impregnating varnish obtained in embodiments 1 to 4, and a certain pressure is applied after the vacuum is removed, so that the insulation impregnating varnish permeates and fills gaps of the coil, the wire slot or other parts.
And after the impregnation is finished, taking the electrical product out of the insulating impregnating varnish, precuring for 5h at 150 ℃, and then curing for 7h at 180 ℃, wherein the cured insulating impregnating varnish and the coated parts form a heat-conducting insulating whole for subsequent use.
Comparative example
Compared with the previous examples, the insulating impregnating varnish based on VPI prepared by the comparative example is mainly different from the insulating impregnating varnish prepared by the previous examples in that the core-shell structured nanoparticles of the application are not adopted, and the insulating impregnating varnish of the comparative example comprises the following raw materials in parts by mass:
Figure BDA0002210983830000121
test example
The VPI-based insulating impregnating varnish prepared in the embodiments 1-4 and the comparative example is tested for corresponding physical and chemical properties according to national standards, and the test results are shown in Table 1.
TABLE 1
Figure BDA0002210983830000122
As can be seen from Table 1, the test results of examples 1 to 4 are improved to a certain extent in viscosity, adhesive strength, impact strength, thermal conductivity and coating amount as compared with the test results of comparative examples; the dielectric loss factor and the volume shrinkage rate are reduced to a certain degree. After the VPI-based insulating impregnating varnish is cured, the mechanical property and the heat conductivity are enhanced, the size stability is good, and the peak temperature is further reduced.

Claims (10)

1. The VPI-based insulating impregnating varnish is characterized by comprising the following raw materials in parts by mass:
Figure FDA0002210983820000011
the nano-particles with the core-shell structure take a resin material as a shell and an energy storage material as a core.
2. A VPI-based insulating impregnating varnish according to claim 1, wherein said resin material is selected from one or more of graphene oxide-epoxy resin composite, graphene oxide-soluble polyimide composite; the energy storage material is selected from one or more of inorganic phase change energy storage materials, organic phase change energy storage materials and composite phase change energy storage materials.
3. A VPI-based insulation impregnating varnish according to claim 2, characterized in that the phase transition temperature of the energy storage material is 20-200 ℃.
4. A VPI-based insulating impregnating varnish according to any one of claims 1 to 3, wherein the core of the core-shell structured nanoparticles is a single-layer core, and the ratio of the core material to the shell material is 1: 3.3 to 3.5.
5. A VPI-based insulating impregnating varnish according to any one of claims 1 to 3, wherein the core of the core-shell structured nanoparticles is a double-layer core, and the ratio of the core material to the shell material is 1: 1.6-1.8, wherein the dosage ratio of the outer layer material of the core to the inner layer material of the core is 1:2.0 to 2.2.
6. A VPI-based insulation impregnating varnish according to claim 1, characterized in that the raw materials of the insulation impregnating varnish comprise, in parts by mass:
Figure FDA0002210983820000012
7. a VPI-based insulating impregnating varnish according to claim 6, wherein the matrix resin comprises, in parts by mass:
60-70 parts of unsaturated polyester;
45-55 parts of novolac epoxy.
8. A VPI-based insulation impregnating varnish according to claim 1, characterized in that the curing agent is tung oil anhydride, the initiator is dicumyl peroxide, the accelerator is cobalt naphthenate and the diluent is trimethylolpropane triacrylate.
9. A VPI-based insulation impregnating varnish according to claim 1, characterized in that the raw materials of the insulation impregnating varnish comprise, in parts by mass:
Figure FDA0002210983820000022
the shell of the nano-particles with the core-shell structure is a graphene oxide-epoxy resin compound; the core of the nanoparticle with the core-shell structure is pentaerythritol and neopentyl glycol.
10. The method for insulating an electrical product, characterized in that the electrical product is impregnated with the VPI-based insulating impregnating varnish according to any one of claims 1 to 9, pre-cured at 140 to 150 ℃ for 4 to 5 hours after impregnation, and then re-cured at 170 to 180 ℃ for 7 to 8 hours to complete the insulating treatment.
CN201910898277.3A 2019-09-23 2019-09-23 VPI-based insulating impregnating varnish and insulating treatment method of electrical product Withdrawn CN110776813A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112908600A (en) * 2021-02-20 2021-06-04 浙江博菲电气股份有限公司 High-strength drawing magnetic slot wedge and manufacturing method thereof

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112908600A (en) * 2021-02-20 2021-06-04 浙江博菲电气股份有限公司 High-strength drawing magnetic slot wedge and manufacturing method thereof
CN112908600B (en) * 2021-02-20 2024-04-05 浙江博菲电气股份有限公司 High-strength drawing magnetic slot wedge and manufacturing method thereof

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Application publication date: 20200211