Epoxy impregnating resin capable of being subjected to vacuum infusion for multiple times and application

Abstract

The invention discloses epoxy impregnating resin capable of being subjected to vacuum infusion for multiple times, which comprises 10-30 parts of epoxy resin containing dynamic covalent bonds, 30-50 parts of conventional epoxy resin, 5-10 parts of epoxy diluent, 10-25 parts of amine curing agent containing dynamic covalent bonds, 5-20 parts of conventional amine curing agent and 0.1-3 parts of accelerant, the conventional epoxy resin is one or more of phenolic epoxy, bisphenol F type epoxy resin and bisphenol A type epoxy resin; the invention also discloses a method for preparing a high-temperature superconducting magnet. The technical problems that in the prior art, insulating impregnating resin cannot be degraded, superconducting wires cannot be recycled, and fault points are difficult to position accurately can be solved, the degraded superconducting wires can be recycled in a lossless mode, and the problem that the design verification cost of an existing high-temperature superconducting magnet technology is high can be effectively solved.

Description

Technical Field

[0001] This invention belongs to the field of high-temperature superconducting magnet impregnation resin technology, and specifically relates to an epoxy impregnation resin that can be repeatedly vacuum-infused, and its application in high-temperature superconducting magnets. Background Technology

[0002] Superconducting motors, due to their zero-resistance characteristics, can achieve ultra-high efficiency operation at low temperatures, saving more than 50% energy compared to traditional motors. They are widely used in high-power power generation, maglev trains, medical imaging equipment, and other fields. Their core component—the high-temperature superconducting magnet—requires high-performance insulating materials to ensure operational safety. Superconducting motors typically operate in liquid nitrogen or cryogenic refrigerant environments at -196°C, placing stringent requirements on the low-temperature mechanical strength, linear shrinkage rate, and dielectric properties of the insulating materials. The high-temperature superconducting magnet, as the core component of a superconducting motor, is also the most expensive and fragile component, accounting for approximately half of the total cost of the motor.

[0003] In the research and production of high-temperature superconducting magnets, damage is inevitable due to improper operation during the impregnation and curing process, external impacts, electric fields, magnetic fields, or the equipment reaching its service life. Traditional epoxy resin cannot be peeled off from superconducting wires because it is insoluble and infusible. At the same time, due to its complex multi-layered structure, superconducting wires cannot withstand temperatures above 200°C. Removing the resin coating by incineration will directly damage the superconducting layer lattice, making it impossible to recycle and reuse the superconducting wires, resulting in a huge waste.

[0004] Therefore, the application of biodegradable epoxy resin as the impregnating insulating resin in high-temperature superconducting magnets is imperative to ensure the intact recycling and reuse of these magnets. Simultaneously, the controllable degradation characteristics of the impregnating resin in high-temperature superconducting magnets can be transformed into a highly valuable fault diagnosis tool, enabling precise location and analysis of magnet fault points. Research on the application and development status of repeatedly vacuum-injectable epoxy impregnating resins in high-temperature superconducting magnets is of great significance for promoting the green and sustainable development of high-temperature superconducting magnets in my country. Summary of the Invention

[0005] One of the objectives of this invention is to overcome the above-mentioned technical deficiencies and to propose an epoxy impregnation resin that can be vacuum-infused multiple times.

[0006] The technical solution adopted by this invention to solve its technical problem is: an epoxy impregnation resin that can be vacuum-infused multiple times, comprising, by weight, 10-30 parts of epoxy resin containing dynamic covalent bonds, 30-50 parts of conventional epoxy resin, 5-10 parts of epoxy diluent, 10-25 parts of amine curing agent containing dynamic covalent bonds, 5-20 parts of conventional amine curing agent, and 0.1-3 parts of accelerator; wherein the conventional epoxy resin is one or more of phenolic epoxy, bisphenol F type epoxy resin, and bisphenol A type epoxy resin; and the epoxy resin containing dynamic covalent bonds is shown in Formula I. In the formula, n≥1.

[0007] The epoxy impregnation resin that can be vacuum-infused multiple times has an epoxy diluent that is one or more of 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, and C12-14 alkyl glycidyl ether.

[0008] The epoxy impregnation resin that can be vacuum-infused multiple times contains an amine curing agent with dynamic covalent bonds, which is one or more of 2,2′-dithiodiethylamine, 2,2′-diaminodiphenyl disulfide, and 4,4′-diaminodiphenyl disulfide.

[0009] The epoxy impregnation resin that can be vacuum-infused multiple times has one or more conventional amine curing agents selected from polyetheramine D230, polyetheramine D400, polyetheramine D2000, polyamide 650, isoflurane diamine, and 1,3-cyclohexanedimethylamine.

[0010] The epoxy impregnation resin that can be vacuum-infused multiple times has an accelerator that is one or more of 2,4,6-tris(dimethylaminomethyl)phenol, benzyldimethylamine, and nonylphenol.

[0011] The second objective of this invention is to propose the application of the aforementioned epoxy impregnation resin, which can be vacuum-infused multiple times, in high-temperature superconducting magnets for the preparation of such magnets.

[0012] Furthermore, the preparation method includes the following steps:

[0013] Step 1: Starting from the innermost layer, the superconducting wire is wound outwards along the spiral direction to form a high-temperature superconducting magnet with a disc-like structure.

[0014] Step 2: Place the high-temperature superconducting magnet into the varnish-impregnated mold and evacuate it to below 1000 Pa.

[0015] Step 3: Under vacuum conditions, epoxy impregnation resin that can be vacuum-injected multiple times is poured into the impregnation mold until the high-temperature superconducting magnet is completely immersed.

[0016] Step 4: Place the impregnated high-temperature superconducting magnet at room temperature for more than 24 hours until it is completely cured.

[0017] Furthermore, when the prepared high-temperature superconducting magnet is unqualified or damaged and needs to be disassembled, the high-temperature superconducting magnet, which has been impregnated and cured with epoxy impregnation resin that can be vacuum-injected multiple times, is heated in a degradation solution. The cured epoxy impregnation resin can degrade and lose its bonding strength, and the superconducting wire can be recycled and reused without damage.

[0018] Furthermore, the degradation solution is one or more of the following: dithiothreitol, 2-mercaptoethanol, 1,2-ethanedithiol, n-butanethiol, 1,6-hexanedithiol, diphenyl ether, biphenyl, and tetrahydrofuran.

[0019] Furthermore, the heating temperature range in the degradation solution is 60–130°C, and the heating time is 1–24 hours.

[0020] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0021] The epoxy impregnation resin provided by this invention contains dynamic covalent bonds in both the epoxy resin and the curing agent. During the resin's reaction and curing stage, the dynamically reactive disulfide bonds are distributed within the cross-linking and curing reaction-generated network of three-dimensional macromolecular resin. After curing, the resin exhibits high bonding strength, low-temperature resistance, and low linear shrinkage. When a high-temperature superconducting magnet carries a large current, the cured epoxy impregnation resin maintains excellent mechanical strength under low-temperature conditions, preventing displacement and deformation of the superconducting wire that could lead to localized cracking or delamination, affecting current-carrying capacity and causing localized critical conditions. When the critical current decreases below the applied current, the resistivity at that point increases dramatically, resulting in the loss of superconductivity. If the current-carrying capacity of a vacuum-impregnated high-temperature superconducting magnet fails to meet design requirements, it can be immersed in a degradation solution to decompose the magnet. After resin degradation, the superconducting wire can be opened without damage, rewound, and vacuum-impregnated again. This effectively solves the problems of high verification costs and significant economic losses caused by the inability to repeatedly vacuum-impregnate existing high-temperature superconducting magnets during design and repair stages, and the inability to reuse superconducting wires. Furthermore, the controllable degradation characteristics of the impregnating resin can be transformed into a valuable fault diagnosis tool, enabling precise location and analysis of equipment faults and further optimization of the high-temperature superconducting magnet design. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0023] This invention discloses a reusable vacuum-injectable epoxy impregnation resin, comprising, by weight, 10-30 parts of an epoxy resin containing dynamic covalent bonds, 30-50 parts of a conventional epoxy resin, 5-10 parts of an epoxy diluent, 10-25 parts of an amine curing agent containing dynamic covalent bonds, 5-20 parts of a conventional amine curing agent, and 0.1-3 parts of an accelerator; the conventional epoxy resin is one or more of phenolic epoxy, bisphenol F type epoxy resin, and bisphenol A type epoxy resin; the epoxy resin containing dynamic covalent bonds is shown in Formula I: In the formula, n≥1.

[0024] Examples 1-4 and Comparative Example 5 provide formulations of different epoxy impregnation resins that can be vacuum-infused multiple times, and compare them with conventional epoxy impregnation resins. The composition and weight parts of each raw material are shown in the table below.

[0025] .

[0026] After mixing, the mixture was cured at room temperature for 24 hours. The conventional properties of the impregnating resin were tested, and its degradability was evaluated using a degradation solution at 110°C. The performance tests of the epoxy impregnating resin are shown in the table below.

[0027] .

[0028] The higher the content of epoxy resin and curing agent containing dynamic covalent bonds, the shorter the time required for degradation in the degradation solution. Conventional epoxy impregnation resin cured products are not degradable. Based on comprehensive comparison, Example 1 was used for vacuum impregnation of high-temperature superconducting magnets.

[0029] Example 6: In this example, the steps for preparing a high-temperature superconducting magnet using epoxy impregnation resin that can be vacuum-infused multiple times are as follows.

[0030] Step 1: Starting from the innermost layer, the superconducting wire is wound outwards along the spiral direction in a circular mold with a diameter of 10cm to form a high-temperature superconducting magnet with a disc-like structure. The wire is wound to a thickness of 20mm.

[0031] Step 2: Place the high-temperature superconducting magnet into the impregnation mold and evacuate it to below 1000 Pa.

[0032] Step 3: Under vacuum conditions, epoxy impregnation resin that can be vacuum-injected multiple times is poured into the impregnation mold until the high-temperature superconducting magnet is completely immersed.

[0033] Step 4: Place the impregnated high-temperature superconducting magnet at room temperature for more than 24 hours until it is completely cured.

[0034] High-temperature superconducting magnets, which are impregnated and cured with epoxy impregnation resin that can be vacuum-infused multiple times, are heated in a degradation solution. The cured epoxy impregnation resin degrades and loses its adhesive strength, allowing the superconducting wires to be recycled and reused without damage.

[0035] Example 7: The high-temperature superconducting magnet used in this example has a winding method that differs from that in Example 6 in that the wire winding thickness in step 1 is 30mm.

[0036] Example 8: The high-temperature superconducting magnet used in this example has a winding method that differs from that in Example 6 in that the wire winding thickness in step 1 is 40mm.

[0037] Example 9: The high-temperature superconducting magnet used in this example is wound in a way that differs from that in Example 6 in that in step 1, it is wound outward gradually along the spiral direction in a circular mold with a diameter of 20cm.

[0038] Example 10: The high-temperature superconducting magnet used in this example has a different winding method from that in Example 6 in step 1, it is wound outward gradually along the spiral direction in a circular mold with a diameter of 30cm, and the wire winding thickness is 30mm.

[0039] The above-mentioned high-temperature superconducting magnets were tested at 77K. The table below shows the performance test results of the high-temperature superconducting magnets.

[0040] .

[0041] As can be seen from Examples 6-10, high-temperature superconducting magnets of different thicknesses and sizes wound with superconducting wires, after vacuum impregnation and curing as described in Example 1, all meet the performance requirements. After degradation by the degradation solution, the superconducting wires can be opened without damage, with virtually no attenuation of current-carrying capacity, and can be repeatedly wound and shaped. When the high-temperature superconducting magnet fails to meet performance requirements due to design flaws or impregnation processes, the superconducting wires can be removed without damage, rewound, and vacuum impregnated again. This effectively solves the problems of high verification costs and significant economic losses caused by the inability to repeatedly vacuum impregnate and reuse superconducting wires during the design and repair stages of existing high-temperature superconducting magnets. Furthermore, the controllable degradation characteristics of the impregnation resin can be transformed into a highly valuable fault diagnosis tool, enabling precise location and analysis of equipment fault points, and further optimizing the design of high-temperature superconducting magnets.

[0042] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An epoxy impregnation resin capable of multiple vacuum infusions, characterized in that: Its components, by weight, include 10-30 parts of epoxy resin containing dynamic covalent bonds, 30-50 parts of conventional epoxy resin, 5-10 parts of epoxy diluent, 10-25 parts of amine curing agent containing dynamic covalent bonds, 5-20 parts of conventional amine curing agent, and 0.1-3 parts of accelerator; the conventional epoxy resin is one or more of phenolic epoxy, bisphenol F type epoxy resin, and bisphenol A type epoxy resin; the structural formula of the epoxy resin containing dynamic covalent bonds is... In the formula, n≥1.

2. The epoxy impregnation resin capable of multiple vacuum infusions according to claim 1, characterized in that, The epoxy diluent is one or more of 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, and C12-14 alkyl glycidyl ether.

3. An epoxy impregnation resin capable of multiple vacuum infusions according to claim 1 or 2, characterized in that, The amine curing agent containing dynamic covalent bonds is one or more of 2,2′-dithiodiethylamine, 2,2′-diaminodiphenyl disulfide, and 4,4′-diaminodiphenyl disulfide.

4. The epoxy impregnation resin capable of multiple vacuum infusions according to claim 3, characterized in that, The conventional amine curing agent is one or more of polyetheramine D230, polyetheramine D400, polyetheramine D2000, polyamide 650, isoflurane diamine, and 1,3-cyclohexanedimethylamine.

5. The epoxy impregnation resin capable of multiple vacuum infusions according to claim 4, characterized in that, The accelerator is one or more of 2,4,6-tris(dimethylaminomethyl)phenol, benzyldimethylamine, phenol, and nonylphenol.

6. The epoxy impregnation resin capable of multiple vacuum infusion as described in any one of claims 1 to 5 is used to prepare high-temperature superconducting magnets.

7. The application according to claim 6, characterized in that, The preparation method includes the following steps: Step 1: Starting from the innermost layer, the superconducting wire is wound outwards along the spiral direction to form a disc-shaped high-temperature superconducting magnet. Step 2: Place the high-temperature superconducting magnet into the varnish-impregnated mold and evacuate it to below 1000 Pa. Step 3: Under vacuum conditions, epoxy impregnation resin that can be vacuum-injected multiple times is poured into the impregnation mold until the high-temperature superconducting magnet is completely immersed. Step 4: Place the impregnated high-temperature superconducting magnet at room temperature for more than 24 hours until it is completely cured.

8. The application according to claim 7, characterized in that, When the prepared high-temperature superconducting magnet is unqualified or damaged and needs to be dismantled, the high-temperature superconducting magnet, which has been impregnated and cured with epoxy resin, is heated in a degradation solution to recycle and reuse the superconducting wire.

9. The application according to claim 8, characterized in that, The degradation solution is one or more of the following: dithiothreitol, 2-mercaptoethanol, 1,2-ethanedithiol, n-butanethiol, 1,6-hexanedithiol, diphenyl ether, biphenyl, tetrahydrofuran.

10. The application according to claim 8, characterized in that, The degradation solution is heated at a temperature of 60–130°C for 1–24 hours.

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