High-thermal-conductivity insulating pouring glue for large-scale motor, and preparation method and application thereof

Abstract

The invention discloses a high-thermal-conductivity insulating pouring adhesive for a large-scale motor, a preparation method and application, and the preparation method comprises the following steps: step 1, mixing high-purity nanoscale beryllium oxide powder and micron-sized spherical inorganic filler in proportion, stirring, heating, preserving heat and cooling to obtain beryllium composite microspheres with high thermal conductivity; 2, mixing the beryllium composite microspheres obtained in the step 1 with an inert dispersant and a surface modifier, and stirring at a specific temperature to perform a modification reaction; after the reaction is completed, sequentially performing filtering, drying and ball milling treatment to obtain surface-modified beryllium composite microspheres with high thermal conductivity; and step 3, adding the surface-modified beryllium composite microspheres obtained in the step 2 into an insulating resin matrix as a heat-conducting filler to prepare the high-heat-conductivity insulating pouring adhesive. Compared with aluminum oxide, boron nitride and the like, the thermal conductivity of added beryllium oxide is increased; compared with the addition of pure beryllium oxide, the beryllium composite microsphere provided by the invention has the advantage that the use amount of beryllium oxide is reduced, so that the cost is greatly reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electrical materials, in particular to a high-thermal-conductivity insulating pouring glue for large-scale electric machines, a preparation method and applications. BACKGROUND

[0002] Insulating pouring glue is a liquid or paste high-molecular insulating material, which is usually filled into a container or mold containing electronic components, circuits, coils or joints by pouring or pouring, and forms a solid insulating protective body with complete structure and stable performance after curing. Among them, epoxy pouring glue is the most widely used, which has the advantages of high mechanical strength, high hardness, excellent adhesion, good chemical corrosion resistance, excellent insulating performance and relatively low cost. However, such materials generally have the problems of brittle texture and poor cold and hot impact resistance, which are prone to cracking due to thermal expansion and cold contraction when the temperature changes sharply. Common epoxy pouring glue is usually a two-component system (component A is resin and component B is curing agent), which needs to be accurately mixed in proportion before use, and then the curing process is completed. Such materials are widely used in fields with high requirements for electrical strength, mechanical strength and protection performance, such as large-scale electric machines, cable accessories, transformers, solar energy, wind energy, aerospace and national defense industry.

[0003] The main material of insulating pouring glue is high-molecular polymer, and its thermal conductivity is usually low. However, the electrical unit wrapped in it will inevitably generate heat during operation. If this part of heat cannot be dissipated in time, the overall temperature of the pouring glue will continue to rise until the heat dissipation rate and heat generation rate reach equilibrium. With the increase of the use volume of the pouring glue, and the poor thermal conductivity of the external medium (such as air or other materials in contact with it), the temperature of the pouring glue in the heat balance state will be significantly increased. High temperature environment will accelerate the aging of high-molecular material, and then affect the working reliability and service life of the device. Therefore, it is of great engineering significance to improve the thermal conductivity of insulating pouring glue and reduce its temperature rise in stable working state.

[0004] At present, the existing technology improves the thermal conductivity of the pouring glue by adding thermal conductive fillers (such as alumina, boron nitride, etc.) in it, and achieves certain cooling effect. However, limited by the thermal conductivity of such fillers, the improvement effect is limited. Especially in high altitude and other special environments, the deterioration of heat dissipation conditions caused by the decrease of air density puts forward higher requirements for the thermal conductivity of insulating pouring glue.

[0005] Beryllium oxide (BeO) as a kind of inorganic compound composed of beryllium and oxygen elements, usually white powder, can form a dense white or off-white ceramic material after sintering, belongs to hexagonal system. Among the common non-conductive materials, beryllium oxide has very high thermal conductivity, which can reach 250-330 W / (m·K) at room temperature, about ten times that of aluminum oxide, and even comparable to some metals. At the same time, beryllium oxide has high resistivity, and its addition will not damage the insulation performance of the pouring glue, which is unmatched by high thermal conductivity metal materials.

[0006] However, the price of beryllium oxide material is expensive, which limits its application. If a smaller amount of material can achieve better thermal conductivity, the material cost of high thermal conductivity insulation pouring glue can be greatly reduced and its application range can be further expanded.

[0007] Therefore, it has become an urgent need in the technical development of the field to develop an insulation pouring glue with high thermal conductivity, excellent insulation performance and cost-effectiveness. SUMMARY

[0008] The present application aims to solve the problem of how to develop an insulation pouring glue with high thermal conductivity, excellent insulation performance and cost-effectiveness, and provides a high thermal conductivity insulation pouring glue for large motors, a preparation method and application.

[0009] In order to achieve the above technical purpose, the technical scheme provided by the present application is as follows: A preparation method of a high thermal conductivity insulation pouring glue for large motors, comprising the following steps: Step 1: Mix high-purity nanoscale beryllium oxide powder and micron-sized spherical inorganic fillers in proportion, and after stirring, heating and holding, and cooling treatment, obtain beryllium composite microspheres with high thermal conductivity; Step 2: Mix the beryllium composite microspheres obtained in step 1 with inert dispersants and surface modifiers, and stir for modification reaction at a specific temperature; after the reaction is completed, sequentially filter, dry and ball mill to obtain surface-modified beryllium composite microspheres with high thermal conductivity; Step 3: Add the surface-modified beryllium composite microspheres obtained in step 2 to the insulation resin to obtain a high thermal conductivity insulation pouring glue.

[0010] Further, in step 1, the mass ratio of beryllium oxide to micron-sized spherical inorganic material is 1:5 to 1:50.

[0011] Further, in step 1, the micron-sized spherical inorganic material product includes any one of spherical silica, spherical glass, and spherical ceramic; the micron-sized spherical inorganic material has a particle size of 50-100 μm; the purity of beryllium oxide is greater than 99%, and the particle size is less than 500 μm, and the particle size is preferably 400-500 μm.

[0012] Further, in step 1, the heating rate is 5-30℃ / min, and the heating temperature reaches the melting point of the spherical inorganic material plus 2-5℃, and then the heating is stopped; the holding time is 5-30 min; and the cooling rate is 5-30℃ / min.

[0013] Further, in step 2, the mass ratio of the inert dispersant to the beryllium composite microspheres is 1:1-10:1; and the mass ratio of the surface modifier to the beryllium composite microspheres is 1:100-1:10.

[0014] Further, in step 2, the reaction temperature is 40-70℃, and the reaction time is 0.5-5 h.

[0015] Further, in step 3, the mass ratio of the high-thermal-conductivity beryllium composite microspheres after surface modification to the insulating resin is 50:100-100:50; and the insulating resin includes any one of single-component or double-component epoxy resin, polyurethane resin, or silicone resin.

[0016] Further, in step 2, the inert dispersant includes any one of dimethylbenzene, diesel oil, kerosene, liquid paraffin, or low-viscosity methyl silicone oil; and the surface modifier includes any one of sodium dodecyl sulfate, sodium dodecylbenzenesulfonate, polyoxyethylene sorbitan monooleate 85, polyoxyethylene sorbitan monooleate 83, polyoxyethylene sorbitan monooleate 80, polyoxyethylene sorbitan monooleate 65, polyoxyethylene sorbitan monooleate 60, polyoxyethylene sorbitan monooleate 40, polyoxyethylene sorbitan monooleate 20, emulsifier OP10, fatty alcohol polyoxyethylene ether sodium sulfate, peregal, Turkey red oil, propylene glycol alginate, or silane coupling agent.

[0017] The application further provides a high-thermal-conductivity insulating pouring glue for large-sized electric machines.

[0018] The application further provides application of the high-thermal-conductivity insulating pouring glue in large-sized electric machines.

[0019] The application has the following beneficial effects: 1. Compared with addition of alumina or boron nitride, the thermal conductivity of the application is significantly increased by addition of beryllium oxide.

[0020] 2. Compared with addition of pure beryllium oxide, the application reduces the amount of beryllium oxide, and thus greatly reduces the cost. DETAILED DESCRIPTION

[0021] The technical solutions of the present application will be described clearly and completely below. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the present application.

[0022] In addition, the technical features involved in different embodiments of the present application described below can be combined with each other as long as they do not conflict with each other. Embodiment 1

[0023] A preparation method of high-thermal-conductivity insulating pouring glue for large motors comprises the following steps: Step 1: preparing high-thermal-conductivity beryllium composite microspheres Specifically, glass microsphere products with a particle size of 100 μm are purchased, and the melting point thereof is tested to be 950 ℃. Take 50 kg of the glass microspheres, and add 5 kg of nano-sized ultra-fine beryllium oxide powder. Mechanically stir the materials, and increase the temperature of the materials to 952 ℃ at a temperature increasing rate of 15 ℃ / min. Stop increasing the temperature, keep stirring, and maintain the temperature for 30 min, so that the surface of the spherical inorganic material is fused with the beryllium oxide powder. Then, decrease the temperature at a rate of 15 ℃ / min while stirring, to obtain high-thermal-conductivity beryllium composite microspheres.

[0024] Step 2: surface modification of the high-thermal-conductivity beryllium composite microspheres Specifically, take 50 kg of the beryllium composite microspheres prepared in Step 1, and add them to 55 kg of inert dispersant kerosene. Mechanically stir the mixture to obtain a dispersion. Add 3 kg of surface modifier polyoxyethylene sorbitan monooleate 40 (Tween 40), and perform a modification reaction at 55 ℃ for 2 h. Filter, dry, and simply mill the product, to obtain high-thermal-conductivity beryllium composite microspheres that have been surface modified.

[0025] Step 3: add the high-thermal-conductivity beryllium composite microspheres to insulating resin to prepare high-thermal-conductivity insulating pouring glue.

[0026] Specifically, take 10 kg of the composite microspheres that have been surface modified in Step 2, and add them to 20 kg of A component of two-component epoxy pouring glue, and fully stir the mixture to obtain a uniform mixture.

[0027] After curing, the thermal conductivity of the product can reach 8.5 W / m.K.

[0028] As a comparison, the thermal conductivity of a product obtained by adding the same proportion of aluminum oxide to epoxy pouring glue and curing the mixture is about 0.9 W / m.K. Embodiment 2

[0029] A preparation method of high-thermal-conductivity insulating pouring glue for large motors comprises the following steps: Step 1: Preparation of high thermal conductivity beryllium composite microspheres; Silica microsphere product with a particle size of 150 μm was purchased, and its melting point was tested to be 1785℃; Specifically, 100 kg of the silica microspheres were taken, and 15 kg of nano-sized ultra-fine beryllium oxide powder was added; mechanical stirring was performed, the temperature of the material was raised to 1788℃ at a temperature raising rate of 20℃ / min, the temperature raising was stopped, stirring was maintained, and heat preservation was performed for 30 min, so that the spherical silica surface was integrated with the beryllium oxide powder. Then, the temperature was lowered at a rate of 20℃ / min while stirring, and high thermal conductivity beryllium composite microspheres were obtained.

[0030] Step 2: Surface modification of high thermal conductivity beryllium composite microspheres; Specifically, 100 kg of the composite microspheres prepared in step 1 were taken and added to 220 kg of inert dispersant xylene, and mechanical stirring was performed to obtain a dispersion; 5 kg of surface modifier KH550 was added, and a modification reaction was performed at 40℃ for 1.5 h; the product was filtered, dried, and simply ball milled to obtain high thermal conductivity beryllium composite microspheres after surface modification.

[0031] Step 3: Preparation of high thermal conductivity insulation pouring glue by adding high thermal conductivity beryllium composite microspheres to insulating resin; Specifically, 20 kg of the composite microspheres after surface modification obtained in step 2 were taken and added to 20 kg of the A component of two-component polyurethane pouring glue, and stirring was performed to obtain uniformity.

[0032] After curing, the thermal conductivity of the product can reach 9.2 W / m.K.

[0033] As a comparison, the thermal conductivity of the product obtained by adding the same proportion of boron nitride to polyurethane pouring glue after curing is about 2.1 W / m.K. Example 3

[0034] A preparation method of high thermal conductivity insulation pouring glue for large motors comprises the following steps: Step 1: Preparation of high thermal conductivity beryllium composite microspheres; Specifically, ceramic microsphere product with a particle size of 100 μm was purchased, and its melting point was tested to be 1140℃; Specifically, 100 kg of the ceramic microspheres were taken, and 20 kg of nano-sized ultra-fine beryllium oxide powder was added; mechanical stirring was performed, the temperature of the material was raised to 1142℃ at a temperature raising rate of 25℃ / min, the temperature raising was stopped, stirring was maintained, and heat preservation was performed for 30 min, so that the spherical ceramic surface was integrated with the beryllium oxide powder. Then, the temperature was lowered at a rate of 25℃ / min while stirring, and high thermal conductivity beryllium composite microspheres were obtained.

[0035] Step 2: Surface modification of high thermal conductivity beryllium composite microspheres; Specifically, 100 kg of the composite microspheres prepared in step 1 is added to 150 kg of inert dispersant liquid paraffin, and stirred mechanically to obtain a dispersion; 7 kg of surface modifier KH570 is added, and a modification reaction is carried out at 45°C for 3 h; the product is filtered, dried, and simply ball-milled to obtain high-thermal-conductivity beryllium composite microspheres which have been surface-modified.

[0036] Step 3: high-thermal-conductivity beryllium composite microspheres are added to an insulating resin to prepare high-thermal-conductivity insulating pouring glue; Specifically, 20 kg of the composite microspheres which have been surface-modified in step 2 is added to 18 kg of the A component of two-component silicone pouring glue, and stirred thoroughly.

[0037] After curing, the thermal conductivity of the product can reach 9.8 W / m.K.

[0038] As a comparison, the thermal conductivity of the product obtained by adding boron nitride in the same proportion to silicone pouring glue and curing is about 2.6 W / m.K.

[0039] Although the embodiments of the present application have been shown and described, it is understood that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present application, and the scope of the present application is defined by the appended claims and their equivalents.

[0040] The above detailed description is a detailed description of the present application, and cannot be considered as limiting the specific embodiments of the present application to these descriptions. For those skilled in the art, several simple deductions and substitutions can be made without departing from the concept of the present application, and all of them should be considered as falling within the protection scope of the present application.

Claims

1. A method for preparing high-thermal-conductivity insulating potting adhesive for large electric machines, characterized by, It comprises the following steps: Step 1: mixing beryllium oxide powder with micron-sized spherical inorganic filler in proportion, stirring, heating, holding and cooling to obtain high-thermal-conductivity beryllium composite microspheres; Step 2: mixing the beryllium composite microspheres obtained in Step 1 with inert dispersant and surface modifier, stirring at a specific temperature to perform modification reaction; after the reaction, filtering, drying and ball milling to obtain surface-modified high-thermal-conductivity beryllium composite microspheres; Step 3: adding the surface-modified beryllium composite microspheres obtained in Step 2 to insulating resin to obtain high-thermal-conductivity insulating pouring glue.

2. The method for preparing high thermal conductive insulating potting adhesive for large electric machines according to claim 1, characterized in that, In Step 1, the mass ratio of beryllium oxide to micron-sized spherical inorganic material is 1:5-1:

50.

3. The method for preparing a high thermal conductivity insulating potting compound for large motors according to claim 1, characterized in that, In Step 1, the micron-sized spherical inorganic material product includes any one of spherical silica, spherical glass and spherical ceramic; the micron-sized spherical inorganic material has a particle size of 50-100 μm; the purity of beryllium oxide is greater than 99% and the particle size is less than 500 μm.

4. The method for preparing a high thermal conductivity insulating potting compound for large motors according to claim 1, characterized in that, In Step 1, the heating rate is 5-30 ℃ / min, the heating temperature is stopped to rise when it reaches 2-5 ℃ above the melting point of the spherical inorganic material; the holding time is 5-30 min; and the cooling rate is 5-30 ℃ / min.

5. A method for preparing a high thermal conductivity insulating potting compound for large motors according to claim 1, characterized in that, In Step 2, the mass ratio of inert dispersant to beryllium composite microspheres is 1:1-10:1; and the mass ratio of surface modifier to beryllium composite microspheres is 1:100-1:

10.

6. A method for preparing a high thermal conductivity insulating potting compound for large motors according to claim 1, characterized in that, In Step 2, the reaction temperature is 40-70 ℃ and the reaction time is 0.5-5 h.

7. A method for preparing a high thermal conductivity insulating potting compound for large motors according to claim 1, characterized in that, In Step 3, the mass ratio of surface-modified high-thermal-conductivity beryllium composite microspheres to insulating resin is 50:100-100:50; and the insulating resin includes any one of single-component or double-component epoxy resin, polyurethane resin and silicone resin.

8. A method for preparing a high thermal conductivity insulating potting compound for large motors according to claim 1, characterized in that, In Step 2, the inert dispersant includes any one of dimethylbenzene, diesel oil, kerosene, liquid paraffin and low-viscosity methyl silicone oil; and the surface modifier includes any one of sodium dodecyl sulfate, sodium dodecyl benzene sulfonate, polyoxyethylene sorbitan monooleate 85, polyoxyethylene sorbitan monooleate 83, polyoxyethylene sorbitan monooleate 80, polyoxyethylene sorbitan monooleate 65, polyoxyethylene sorbitan monooleate 60, polyoxyethylene sorbitan monooleate 40, polyoxyethylene sorbitan monooleate 20, emulsifier OP10, sodium fatty alcohol polyoxyethylene ether sulfate, peregal, Turkey red oil, propylene glycol alginate and silane coupling agent.

9. A high-thermal-conductivity insulating pouring glue for large-sized electric machines is prepared by the method of any one of claims 1-8.

10. The high-thermal-conductivity insulating pouring glue of claim 9 is applied to large-sized electric machines.