Two-component polyurethane pouring sealant for capacitor potting and preparation method of two-component polyurethane pouring sealant

Abstract

The invention discloses a two-component polyurethane pouring sealant for capacitor potting and a preparation method thereof, and belongs to the field of pouring sealants. The pouring sealant comprises a component A and a component B in a mass ratio of 100: 30, wherein the component A is a main agent and comprises modified castor oil, a diluent, polyether polyol, a defoaming aid, a heat-conducting filler, a special waterproof material, a common filler and a molecular sieve filler; the component B is a curing agent and comprises modified isocyanate, bifunctional polyether polyol and a stabilizer. The polyurethane pouring sealant has the advantages of high heat conductivity, excellent water resistance, damp-heat aging resistance, long room-temperature operable time and the like, and is suitable for multiple industries such as electronic and electric appliances, insulating materials, adhesives, composite materials and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of potting adhesives, and in particular to a two-component polyurethane potting adhesive for capacitor potting and a preparation method thereof. Background Art

[0002] Capacitor potting adhesives are mainly used for potting capacitors. Potting is to pour a liquid composite into the capacitor housing containing electronic components and circuits, and cure it into a thermosetting polymer insulating material with excellent performance at normal temperature or under heating conditions. It can improve the waterproof, moisture-proof and heat dissipation performance of capacitors.

[0003] At present, the common capacitor potting adhesives on the market are mainly epoxy resin-based, silicone resin-based and polyurethane-based. Among them, the molecular main chain structure of polyurethane potting adhesives contains many polar groups and active reaction groups. Therefore, the composition and structure design of polyurethane potting adhesives have an extremely wide range of adjustable changes and can be applied to different substrates and fields with diverse performance requirements. However, its water resistance and anti-humid heat aging performance are insufficient; the heat dissipation has a greater impact on the working stability of capacitors. Therefore, the thermal conductivity of the potting adhesive has become an important reference index for selecting potting adhesives during capacitor encapsulation. The thermal conductivity of the existing polyurethane body is only about 0.2 W / (m·K), far from meeting the heat dissipation requirements of capacitors.

[0004] In view of this, the present invention is specifically proposed. Summary of the Invention

[0005] The purpose of the present invention is to provide a two-component polyurethane potting adhesive for capacitor potting and a preparation method thereof, which can improve the thermal conductivity, and the water resistance meets the requirements of rapid heat dissipation, low water permeability and anti-humid heat aging of capacitors, thereby solving the above technical problems existing in the prior art.

[0006] The purpose of the present invention is achieved through the following technical solutions:

[0007] A two-component polyurethane potting adhesive for capacitor potting, comprising: component A and component B combined in a mass ratio of 100:30; wherein,

[0008] Calculated by mass parts, the component A includes: 10-30 parts of modified castor oil, 1-5 parts of diluent, 5-20 parts of modified bifunctional polyether polyol, 4-20 parts of modified trifunctional polyether polyol, 0.05-1 part of defoaming aid, 0.1-1.5 parts of color paste, 5-15 parts of special water-resistant material, 15-30 parts of thermal conductive filler, 10-50 parts of ordinary filler and 1-5 parts of molecular sieve filler;

[0009] Calculated by mass parts, the component B includes: 75-99 parts of modified isocyanate, 1-20 parts of bifunctional polyether polyol and 1-5 parts of stabilizer.

[0010] A preparation method for a two-component polyurethane potting adhesive for capacitor potting according to the present invention comprises the following steps:

[0011] Preparing component A: Taking each raw material of component A according to the formula of the present invention, adding the modified castor oil, diluent, modified bifunctional polyether polyol and modified trifunctional polyether polyol in the raw materials into a reaction kettle, evacuating at 70-80 °C and stirring at a speed of 300 RPM for 0.5 hour to remove moisture. Subsequently, adding the color paste and defoaming auxiliary agent into the reaction kettle, stirring and mixing evenly at a speed of 200 RPM at 70-80 °C, then adding a special water-resistant material, heat-conducting filler, ordinary filler and molecular sieve filler, evacuating at 50-60 °C and stirring at a speed of 800 RPM for 1 hour to obtain component A with heat conduction, water resistance and aging resistance;

[0012] Preparing component B: Taking each raw material of component B according to the formula of the present invention, adding the bifunctional polyether polyol in the raw materials into a reaction kettle, dehydrating by stirring at a speed of 300 RPM at 90-100 °C for 1 hour. Subsequently, adding the modified isocyanate and stabilizer into the reaction kettle, evacuating at 70-80 °C and stirring at a speed of 300 RPM for 1 hour to obtain component B;

[0013] Combining the above-prepared component A and component B for use according to a mass ratio of 100:30 to obtain a two-component polyurethane potting adhesive for capacitor potting.

[0014] Compared with the prior art, the two-component polyurethane potting adhesive for capacitor potting and its preparation method provided by the present invention have the following beneficial effects:

[0015] By adding a special water-resistant material and a heat-conducting filler in component A, cooperating with a specific proportion of modified castor oil, diluent, modified bifunctional polyether polyol, modified trifunctional polyether polyol, defoaming auxiliary agent, color paste, ordinary filler and molecular sieve filler, and component B composed of modified isocyanate, bifunctional polyether polyol and stabilizer, a heat-conducting polyurethane potting adhesive with low water permeability and resistance to damp heat aging is prepared, which can well meet the relevant requirements of capacitor potting. It can be known through experimental verification that in the aging experiment of capacitors using this potting adhesive under the double 85 conditions, there is no detachment after more than 1700 cycles, and the capacity attenuation is extremely low; the water absorption rate and water permeability are significantly reduced, and the water resistance effect is enhanced; the heat conductivity coefficient is greatly improved, and the heat dissipation effect is obvious; due to the above-mentioned many advantages of this potting adhesive, it is applicable to the capacitor potting industry. Specific embodiments

[0016] The following clearly and completely describes the technical solutions in the embodiments of the present invention in conjunction with the specific content of the present invention; obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments, which does not constitute a limitation to the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the protection scope of the present invention.

[0017] First, the terms that may be used in this article are described as follows:

[0018] The term "and / or" means that either or both of the two can be realized. For example, X and / or Y means that it includes both the case of "X" or "Y" and the three cases of "X and Y".

[0019] The description of terms such as "comprising", "including", "containing", "having" or other similar semantics should be interpreted as non-exclusive inclusion. For example: including a certain technical feature element (such as raw material, component, ingredient, carrier, dosage form, material, size, part, component, mechanism, device, step, process, method, reaction condition, processing condition, parameter, algorithm, signal, data, product or article, etc.) should be interpreted as not only including the clearly listed certain technical feature element, but also including other technical feature elements well-known in the art that are not clearly listed.

[0020] The term "consisting of" means excluding any technical feature element that is not clearly listed. If this term is used in a claim, then this term will make the claim a closed type, making it not contain technical feature elements other than the clearly listed ones, except for related conventional impurities. If this term only appears in a certain clause of the claim, then it only limits the elements clearly listed in that clause, and the elements recorded in other clauses are not excluded from the overall claim.

[0021] The term "parts by mass" represents the mass ratio relationship between multiple components. For example: if it is described that component X is x parts by mass and component Y is y parts by mass, then it means that the mass ratio of component X to component Y is x:y; 1 part by mass can represent any mass. For example: 1 part by mass can be expressed as 1 kg or 3.1415926 kg, etc. The sum of the parts by mass of all components is not necessarily 100 parts, and can be greater than 100 parts, less than 100 parts or equal to 100 parts. Unless otherwise specified, the parts, ratios and percentages described in this article are by mass.

[0022] When concentration, temperature, pressure, size or other parameters are expressed in the form of a numerical range, the numerical range should be understood as specifically disclosing all ranges formed by the pairing of any upper limit value, lower limit value, and preferred value within the numerical range, regardless of whether the range is explicitly recorded; for example, if the numerical range "2 to 8" is recorded, then this numerical range should be interpreted as including ranges such as "2 to 7", "2 to 6", "5 to 7", "3 to 4 and 6 to 7", "3 to 5 and 7", "2 and 5 to 7", etc. Unless otherwise specified, the numerical ranges recorded herein include both their end values and all integers and fractions within the numerical range.

[0023] The following is a detailed description of the solution provided by the present invention. The content not described in detail in the embodiments of the present invention belongs to the prior art well-known to those skilled in the art. For those conditions not specified in the embodiments of the present invention, they are carried out according to the conventional conditions in the art or the conditions recommended by the manufacturer. For the reagents or instruments not specified in the embodiments of the present invention for the manufacturer, they are all conventional products that can be obtained through commercial purchase.

[0024] The embodiment of the present invention provides a two-component polyurethane potting adhesive for capacitor potting, including: component A and component B combined in a mass ratio of 100:30; wherein,

[0025] Calculated by mass parts, component A includes: 10 to 30 parts of modified castor oil, 1 to 5 parts of diluent, 5 to 20 parts of modified bifunctional polyether polyol, 4 to 20 parts of modified trifunctional polyether polyol, 0.05 to 1 part of defoaming aid, 0.1 to 1.5 parts of color paste, 5 to 15 parts of special water-resistant material, 15 to 30 parts of heat-conducting filler, 10 to 50 parts of ordinary filler, and 1 to 5 parts of molecular sieve filler;

[0026] Calculated by mass parts, component B includes: 75 to 99 parts of modified isocyanate, 1 to 20 parts of bifunctional polyether polyol, and 1 to 5 parts of stabilizer.

[0027] Preferably, in the above potting adhesive, the modified castor oil in component A is one or two of: refined castor oil, crude castor oil, and hydrogenated castor oil.

[0028] Preferably, in the above potting adhesive, the diluent in component A is one or two of: p-tert-butylphenol, 4-methoxyphenol, 2,6-ditert-butylphenol, 1,4-butanediol diglycidyl ether, benzyl glycidyl ether, C10-C14 alkyl glycidyl ether, neopentyl glycol diglycidyl ether, and cashew phenol glycidyl ether.

[0029] Preferably, in the above potting adhesive, the modified bifunctional polyether polyol in component A is one or more of: polypropylene glycol, polyethylene glycol, and polybutylene glycol with different molecular weights;

[0030] The modified trifunctional polyether polyol is selected from one or more of polyglycerol propylene, polyglycerol ethylene, and polyglycerol butylene with different molecular weights.

[0031] Preferably, in the above potting adhesive, the defoaming aid in component A is selected from one or more of SH5500, A535, BYK996, BYK570, animal and vegetable waxes, palm wax, castor oil, coconut oil, tall oil, and polysiloxane defoamers;

[0032] The ordinary filler is selected from one or more of aluminum hydroxide, spherical silica powder, alumina, calcium carbonate, and fused silica powder;

[0033] The thermal conductive filler is selected from one or two of expanded graphite, worm graphite, and flake graphite. This thermal conductive filler belongs to high-porosity structure graphite fillers.

[0034] Preferably, in the above potting adhesive, the special water-resistant material in component A is prepared by chemical synthesis through the reaction of modified epoxy resin with polypropylene glycol with a molecular weight of 400 and dodecenyl succinic anhydride under the action of a catalyst.

[0035] Preferably, the special water-resistant material in the above potting adhesive is prepared as follows, including:

[0036] By mass, 300 parts of epoxy resin and 100 parts of bisphenol A are added to a reaction kettle, heated to 90 °C, and stirred and reacted at a speed of 200 RPM for 1.5 h. Then it is gradually heated to 140 °C, 100 parts of polydimethylsiloxane are added, and stirred at a speed of 200 RPM for 0.3 h. After the temperature is stable, 1 part of bismuth isooctanoate is added to catalyze the reaction, and the speed is increased to 400 RPM and reacted for 3 h. Then it is gradually cooled to room temperature to obtain polydimethylsiloxane-modified phenolic epoxy resin;

[0037] 300 parts of polypropylene glycol with a molecular weight of 400 and 200 parts of dodecenyl succinic anhydride are put into a reaction kettle and fully mixed, stirred at a speed of 200 RPM for 0.3 h, heated to 60 °C, 5 parts of selenium disulfide powder are added, and vacuum reacted at a speed of 400 RPM for 4 h to form an acid anhydride-polyol composite solution. Then it is heated to 80 °C, and then 1000 parts of the above-prepared polydimethylsiloxane-modified phenolic epoxy resin and 5 parts of boron trifluoride are added, and vacuum reacted at a speed of 400 RPM for 2 h. After completion, it is naturally cooled to room temperature, and the obtained polyol-modified silicone-modified phenolic epoxy resin composite material is the special water-resistant material. This special water-resistant material is easily soluble in the polyol system, contains a large number of silicon-oxygen bonds, has a high dissociation energy, and has strong hydrophobicity.

[0038] Preferably, in the above-mentioned special water-resistant material, the epoxy resin is any one of: F51 type epoxy resin, E51 epoxy resin, E44 epoxy resin, and E31 epoxy resin. In the subsequent description, the special water-resistant material made of F51 type epoxy resin is called A-type modified epoxy resin composite material, the special water-resistant material made of E51 type epoxy resin is called B-type modified epoxy resin composite material, the special water-resistant material made of E44 type epoxy resin is called C-type modified epoxy resin composite material, and the special water-resistant material made of E31 type epoxy resin is called D-type modified epoxy resin composite material.

[0039] Preferably, in the B component of the above-mentioned potting adhesive, the modified isocyanate is one or more of toluene diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, dicyclohexylmethane diisocyanate, diphenylmethane diisocyanate, PM200, and lysine diisocyanate;

[0040] The difunctional polyether polyol is one or more of polypropylene glycol, polyethylene glycol, and polybutylene glycol with different molecular weights;

[0041] The stabilizer is one or two of acetylacetone, sodium diacetate, p-hydroxybenzoate, sorbic acid, and benzoic acid.

[0042] The embodiment of the present invention also provides a preparation method for the two-component polyurethane potting adhesive for capacitor potting as described above, including the following steps:

[0043] Prepare component A: Take each raw material of component A according to the above formula. Add the modified castor oil, diluent, modified difunctional polyether polyol, and modified trifunctional polyether polyol in the raw materials into the reaction kettle, evacuate at 70-80°C and stir at a speed of 300 RPM for 0.5 hour to remove moisture. Then add the color paste and defoaming aid into the reaction kettle, stir and mix evenly at 70-80°C at a speed of 200 RPM, and then add the special water-resistant material, heat-conducting filler, ordinary filler, and molecular sieve filler, evacuate at 50-60°C and stir at a speed of 800 RPM for 1 hour to obtain the heat-conducting, water-resistant, and aging-resistant component A;

[0044] Prepare component B: Take each raw material of component B according to the above formula. Add the difunctional polyether polyol in the raw materials into the reaction kettle, stir at 90-100°C at a speed of 300 RPM for 1 hour to dehydrate. Then add the modified isocyanate and stabilizer into the reaction kettle, evacuate at 70-80°C and stir at a speed of 300 RPM for 1 hour to obtain component B;

[0045] Use the above-prepared component A and component B in a mass ratio of 100:30 to obtain the two-component polyurethane potting adhesive for capacitor potting.

[0046] Preferably, in the above method, the special water-resistant material in the preparation of component A is prepared in the following manner, including:

[0047] Calculated by mass parts of each component, add 300 parts of epoxy resin and 100 parts of bisphenol A into the reaction kettle, heat up to 90 °C, stir and react at a speed of 200 RPM for 1.5 h, gradually heat up to 140 °C, add 100 parts of polydimethylsiloxane, stir at a speed of 200 RPM for 0.3 h, after the temperature is stable, add 1 part of bismuth isooctanoate to catalyze the reaction, increase the speed to 400 RPM and react for 3 h, gradually cool down to room temperature to obtain polydimethylsiloxane-modified phenolic epoxy resin; the epoxy resin used is any one of F51-type epoxy resin, E51 epoxy resin, E44 epoxy resin, and E31 epoxy resin;

[0048] Put 300 parts of polypropylene glycol with a molecular weight of 400 and 200 parts of dodecenyl succinic anhydride into the reaction kettle and mix well, stir at a speed of 200 RPM for 0.3 h, heat up to 60 °C, add 5 parts of selenium disulfide powder and react under vacuum at a speed of 400 RPM for 4 h to form an anhydride-polyol composite solution; heat up to 80 °C, then add 1000 parts of the above-prepared polydimethylsiloxane-modified phenolic epoxy resin and 5 parts of boron trifluoride, and react under vacuum at a speed of 400 RPM for 2 h; after completion, naturally cool down to room temperature, and the obtained polyol-modified silicone-modified phenolic epoxy resin composite material is the special water-resistant material.

[0049] In summary, the polyurethane potting adhesive of the embodiment of the present invention has the advantages of high thermal conductivity, excellent water resistance and heat and humidity aging resistance, and a long room temperature operable time, and is applicable to multiple industries such as electronic appliances, insulating materials, adhesives, and composite materials.

[0050] In order to more clearly show the technical solutions provided by the present invention and the technical effects produced, the following uses specific examples to describe in detail the solutions provided by the embodiments of the present invention.

[0051] In the following embodiments, the preparation method of the special water-resistant material is the same as above, and the special water-resistant material made of F51-type epoxy resin is called A-type modified epoxy resin composite material, the special water-resistant material made of E51-type epoxy resin is called B-type modified epoxy resin composite material, the special water-resistant material made of E44-type epoxy resin is called C-type modified epoxy resin composite material, and the special water-resistant material made of E31-type epoxy resin is called D-type modified epoxy resin composite material.

[0052] Example 1

[0053] This embodiment provides a two-component polyurethane potting adhesive for capacitor potting, which consists of component A and component B. The mass ratio of component A to component B is 100:30. Among them, component A is the main agent and component B is the curing agent.

[0054] Among them, the modified castor oil in component A is hydrogenated castor oil; the diluent is C10-14 alkyl glycidyl ether; the modified difunctional polyether polyol is polypropylene glycol with a molecular weight of 400; the modified trifunctional polyether polyol is glycerol propoxylate with a molecular weight of 500; the defoaming auxiliary agent is BKY088; the color paste is carbon black; the special water-resistant material is type A modified epoxy resin composite material; the thermal conductive filler is expanded graphite filler; the ordinary filler is aluminum hydroxide; the molecular sieve filler is 3A powder. The specific component contents are shown in Table 1.

[0055] Table 1 shows the raw materials and dosages of component A:

[0056]

[0057]

[0058] Among them, the modified isocyanate in component B is toluene diisocyanate (TDI); the difunctional polyether polyol is polypropylene glycol with a molecular weight of 400; the stabilizer is acetylacetone. The specific component contents are shown in Table 2.

[0059] Table 2 shows the raw materials and dosages of component B:

[0060] Component B raw materials Dosage (parts by mass) TDI 80 Polypropylene glycol with a molecular weight of 400 15 Acetylacetone 5

[0061] Example 2:

[0062] This embodiment provides a two-component polyurethane potting adhesive for capacitor potting, which consists of component A and component B. The mass ratio of component A to component B is 100:30. Among them, component A is the main agent and component B is the curing agent.

[0063] Among them, the modified castor oil in component A is refined castor oil; the diluent is benzyl glycidyl ether; the modified difunctional polyether polyol is polypropylene glycol with a molecular weight of 1000; the modified trifunctional polyether polyol is glycerol propoxylate with a molecular weight of 750; the defoaming auxiliary agent is A535; the color paste is iron oxide black; the special water-resistant material is type B modified epoxy resin composite material; the thermal conductive filler is vermicular graphite filler; the ordinary filler is alumina; the molecular sieve filler is 3A powder. The specific component contents are shown in Table 3.

[0064] Table 3 shows the raw materials and dosages of component A:

[0065]

[0066]

[0067] Among them, the modified isocyanate in component B is hexamethylene diisocyanate (HDI); the difunctional polyether polyol used is polypropylene glycol with a molecular weight of 1000; the stabilizer used is sodium diacetate; the specific component contents are shown in Table 4.

[0068] Table 4 shows the raw materials and dosages of component B:

[0069] Component B raw materials Dosage (parts by mass) HDI 85 Polypropylene glycol with a molecular weight of 400 12 Sodium diacetate 3

[0070] Example 3:

[0071] This example provides a two-component polyurethane potting adhesive for capacitor potting, which is composed of component A and component B. The mass ratio of component A to component B is 100:30; among them, component A is the main agent and component B is the curing agent.

[0072] Among them, the modified castor oil in component A is crude castor oil; the diluent used is neopentyl glycol diglycidyl ether; the modified difunctional polyether polyol used is polyethylene glycol with a molecular weight of 2000; the modified trifunctional polyether polyol used is glycerol with a molecular weight of 350; the defoaming aid used is A535; the color paste used is iron oxide red; the special water-resistant filler used is C-type modified epoxy resin composite; the thermal conductive filler used is flake graphite; the ordinary filler used is calcium carbonate filler; the molecular sieve filler used is 3A powder, and the specific component contents are shown in Table 5.

[0073] Table 5 shows the raw materials and dosages of component A:

[0074]

[0075]

[0076] Among them, the modified isocyanate in component B is dicyclohexylmethane diisocyanate (HMDI) and PM200; the difunctional polyether polyol used is polypropylene glycol with a molecular weight of 2000; the stabilizer used is sorbic acid; the specific component contents are shown in Table 6.

[0077] Table 6 shows the raw materials and dosages of component B:

[0078] Component B raw materials Dosage (parts by mass) HMDI 45 PM200 40 Polypropylene glycol with a molecular weight of 2000 12 Sorbic acid 3

[0079] Example 4:

[0080] This example provides a two-component polyurethane potting adhesive for capacitor potting, which is composed of component A and component B. The mass ratio of component A to component B is 100:30; among them, component A is the main agent and component B is the curing agent.

[0081] Among them, the modified castor oil in component A is refined castor oil; the diluent is cardanol glycidyl ether; the modified difunctional polyether polyol is polyethylene glycol and polypropylene glycol with a molecular weight of 400; the modified trifunctional polyether polyol is polypropylene glycol with a molecular weight of 1000; the defoaming agent is BYK570; the color paste is iron oxide yellow; the special water-resistant filler is D-type modified epoxy resin composite material; the thermal conductive filler is expanded graphite and vermicular graphite; the common filler is fused silica micropowder filler; the molecular sieve filler is 3A powder. The specific component contents are shown in Table 7.

[0082] Table 7 shows the raw materials and dosage of component A:

[0083]

[0084]

[0085] Among them, the modified isocyanate in component B is diphenylmethane diisocyanate (MDI) and PM200; the difunctional polyether polyol is polypropylene glycol with a molecular weight of 500; the stabilizer is acetylacetone; the specific component contents are shown in Table 8.

[0086] Table 8 shows the raw materials and dosage of component B:

[0087] Component B raw materials Dosage (parts by mass) MDI 50 PM200 44 Polyglycerol with a molecular weight of 500 4 Acetylacetone 2

[0088] The above examples were compared with the currently available Fuming 7586-3 product. The water permeability (1mm thickness) and water absorption (10g, boiling for 3 hours) at 25°C and 100°C were tested. The thermal conductivity (Hot Disk method) was also tested. The above examples were applied to simulated cylindrical capacitors to test the product's resistance to dual 85°C and dual 95°C aging (85°C / 85RH). The results are shown in Table 9.

[0089] Among them, the double 85 and double 95 aging resistance performance is tested by using PPS material to simulate the capacitor potting. It is observed once every period of time with a high-power magnifying glass until small cracks appear on the surface glue or the shell is slightly detached. At this time, it is considered that water vapor has entered the capacitor, affecting the product capacity and it is judged as a product failure.

[0090] Table 9 is a comparison of the relevant properties of the potting compound of the present invention and existing market products

[0091] Relevant properties Example 1 Example 2 Example 3 Example 4 Fuming 7586-3 Thermal conductivity / [W / (m·K)] 1.64 1.62 1.51 1.53 0.65 Resistance to double 85 performance / h 1750 1750 1780 1700 1200 Resistance to double 95 performance / h 1150 1160 1180 1100 750 <![CDATA[Water permeability at 50℃ / L / (s·m 2 )]]> 0.22 0.24 0.25 0.23 0.76 <![CDATA[Water permeability at 25°C / L / (s·m 2 )]]> 0.11 0.14 0.15 0.13 0.45 Water absorption at 100°C / % 0.15 0.14 0.16 0.13 0.48 Water absorption at 25°C / % 0.05 0.03 0.03 0.04 0.25

[0092] The results in Table 9 above show that compared with the current commercially available product Fuming 7586-3, the formulation with thermal conductivity and special water-resistant materials has significantly improved the double 85 aging resistance performance, and the number of cycles has increased to more than 1700 times; the double 95 aging resistance performance has also been significantly improved, and the number of cycles has reached more than 1100 times, which meets the usage requirements of the client under specific conditions (such as offshore wind power), and can greatly reduce the capacity attenuation of capacitors under damp heat aging conditions; the water permeability at 25 and 50 °C has been significantly reduced, about 1 / 3 less than that of competing products, and the water absorption at 25 and 100 °C also shows an obvious downward trend, about 1 / 4 less than that of competing products. The above can greatly enhance the water resistance performance of the product itself, which is very beneficial to preventing water vapor from entering the capacitor interior through the colloid itself, directly improving the damp heat aging resistance performance of the product itself and strengthening the use safety of the capacitor; the thermal conductivity has increased significantly, which is extremely helpful for alleviating the excessive heat release of large capacitors under high-rate cycling, reducing the risk of thermal runaway, and extending the service life of capacitors, greatly enhancing the number of its usage times.

[0093] As described above, the above are only the preferred specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered by the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims. The information disclosed in the background art part of this article is only intended to deepen the understanding of the overall background technology of the present invention, and should not be regarded as an admission or any form of suggestion that this information constitutes the prior art known to those skilled in the art.

Claims

1. A two-component polyurethane potting adhesive for capacitor potting, characterized in that, Comprising: Component A and Component B combined in a mass ratio of 100:30; wherein, By mass parts, Component A includes: 10 - 30 parts of modified castor oil, 1 - 5 parts of diluent, 5 - 20 parts of modified bifunctional polyether polyol, 4 - 20 parts of modified trifunctional polyether polyol, 0.05 - 1 part of defoaming aid, 0.1 - 1.5 parts of color paste, 5 - 15 parts of special water-resistant material, 15 - 30 parts of heat-conducting filler, 10 - 50 parts of ordinary filler, and 1 - 5 parts of molecular sieve filler; By mass parts, Component B includes: 75 - 99 parts of modified isocyanate, 1 - 20 parts of bifunctional polyether polyol, and 1 - 5 parts of stabilizer.

2. The two-component polyurethane potting adhesive for capacitor potting according to claim 1, wherein, The modified castor oil in Component A is one or two of: refined castor oil, crude castor oil, hydrogenated castor oil; The diluent in Component A is one or two of: p-tert-butylphenol, 4-methoxyphenol, 2,6-ditert-butylphenol, 1,4-butanediol diglycidyl ether, benzyl glycidyl ether, C10 - C14 alkyl glycidyl ether, neopentyl glycol diglycidyl ether, cashew phenol glycidyl ether; 3. The two-component polyurethane potting adhesive for capacitor potting according to claim 1, characterized in that, The modified bifunctional polyether polyol in Component A is one or more of: polypropylene glycol, polyethylene glycol, polybutylene glycol with a molecular weight of 200 - 3000; The modified trifunctional polyether polyol is one or more of: polyglycerol, polyethylglycerol, polybutylglycerol with a molecular weight of 200 - 3000.

4. The two-component polyurethane potting adhesive for capacitor potting according to claim 1, characterized in that, The defoaming aid in Component A is one or two or more of: SH5500, A535, BYK996, BYK570, animal and plant waxes, palm wax, castor oil, coconut oil, tall oil, polysiloxane defoamers; The ordinary filler is one or two or more of: aluminum hydroxide, spherical silica powder, alumina, calcium carbonate, fused silica powder; The heat-conducting filler is one or two of: expanded graphite, worm graphite, flake graphite.

5. The two-component polyurethane potting adhesive for capacitor potting according to any one of claims 1-4, characterized in that, The special water-resistant material in Component A is prepared by chemical synthesis through the reaction of modified epoxy resin with polypropylene glycol with a molecular weight of 400 and dodecenyl succinic anhydride under the action of a catalyst.

6. The two-component polyurethane potting adhesive for capacitor potting according to claim 5, characterized in that, The special water-resistant material is prepared in the following manner, including: By mass parts, add 300 parts of epoxy resin and 100 parts of bisphenol A into a reaction kettle, heat up to 90°C, stir and react at a speed of 200 RPM for 1.5 h, gradually heat up to 140°C, add 100 parts of polydimethylsiloxane, stir at a speed of 200 RPM for 0.3 h, after the temperature is stable, add 1 part of bismuth isooctanoate to catalyze the reaction, increase the speed to 400 RPM and react for 3 h, gradually cool down to room temperature to obtain polydimethylsiloxane-modified phenolic epoxy resin; 300 parts of polypropylene glycol with a molecular weight of 400 and 200 parts of dodecenylsuccinic anhydride are placed in a reactor and fully mixed, stirred at a speed of 200 RPM for 0.3 hours, heated to 60°C, and 5 parts of selenium disulfide powder are added, and vacuum reacted at a speed of 400 RPM for 4 hours to form an anhydride-polyol composite solution; the temperature is raised to 80°C, and then 1000 parts of the above-prepared polydimethylsiloxane-modified phenolic epoxy resin and 5 parts of boron trifluoride are added, and vacuum reacted at a speed of 400 RPM for 2 hours; after completion, the mixture is naturally cooled to room temperature, and the obtained polyol-modified siloxane-modified phenolic epoxy resin composite material is a special water-resistant material.

7. The two-component polyurethane potting adhesive for capacitor potting according to claim 6, characterized in that, The epoxy resin is any one of F51 epoxy resin, E51 epoxy resin, E44 epoxy resin and E31 epoxy resin.

8. The two-component polyurethane potting adhesive for capacitor potting according to any one of claims 1-4, characterized in that In the B component, the modified isocyanate is one or more of toluene diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, dicyclohexylmethane diisocyanate, diphenylmethane diisocyanate, PM200, and lysine diisocyanate; The difunctional polyether polyol is one or more of polypropylene glycol, polyethylene glycol, and polybutylene glycol of different molecular weights; The stabilizer is one or two of acetylacetone, sodium diacetate, p-hydroxybenzoate, sorbic acid and benzoic acid.

9. A method for preparing a two-component polyurethane potting adhesive for capacitor potting according to any one of claims 1 to 8, characterized in that, The following steps are involved: Preparation of component A: taking the raw materials of component A according to the formula of any one of claims 1 to 8, adding the modified castor oil, diluent, modified difunctional polyether polyol and modified trifunctional polyether polyol in the raw materials into a reactor, evacuating the mixture at 70-80° C. and stirring at 300 RPM for 0.5 hour to remove moisture, then adding the color paste and defoaming agent into the reactor, stirring and mixing them at 70-80° C. and 200 RPM to obtain a thermally conductive, water-resistant and aging-resistant component A; Preparation of component B: Prepare the raw materials of component B according to the formulation of any one of claims 1 to 8, add the difunctional polyether polyol in the raw materials to a reactor, stir at 90-100° C. and 300 RPM for 1 hour to dehydrate, then add the modified isocyanate and stabilizer to the reactor, evacuate at 70-80° C. and stir at 300 RPM for 1 hour to prepare component B; The above-prepared component A and component B are combined in a mass ratio of 100:30 to obtain a two-component polyurethane potting adhesive for capacitor potting.

10. The preparation method of the two-component polyurethane potting adhesive for capacitor potting according to claim 9, characterized in that, The special water-resistant material in the preparation of component A is prepared in the following manner, including: 300 parts of epoxy resin and 100 parts of bisphenol A were added to a reactor based on the weight of each component. The temperature was raised to 90° C. and stirred at 200 RPM for 1.5 hours. The temperature was gradually raised to 140° C., 100 parts of polydimethylsiloxane were added, and the mixture was stirred at 200 RPM for 0.3 hours. After the temperature stabilized, 1 part of bismuth isooctanoate was added to catalyze the reaction. The speed was increased to 400 RPM and the reaction was continued for 3 hours. The mixture was gradually cooled to room temperature to obtain a polydimethylsiloxane-modified phenolic epoxy resin. The epoxy resin was any one of F51 epoxy resin, E51 epoxy resin, E44 epoxy resin, and E31 epoxy resin. 300 parts of polypropylene glycol with a molecular weight of 400 and 200 parts of dodecenylsuccinic anhydride are placed in a reactor and fully mixed, stirred at a speed of 200 RPM for 0.3 hours, heated to 60°C, and 5 parts of selenium disulfide powder are added, and vacuum reacted at a speed of 400 RPM for 4 hours to form an anhydride-polyol composite solution; the temperature is raised to 80°C, and then 1000 parts of the above-prepared polydimethylsiloxane-modified phenolic epoxy resin and 5 parts of boron trifluoride are added, and vacuum reacted at a speed of 400 RPM for 2 hours; after completion, the mixture is naturally cooled to room temperature, and the obtained polyol-modified siloxane-modified phenolic epoxy resin composite material is a special water-resistant material.

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