Repeatable vpi impregnated epoxy anhydride resins and formed windings comprising same

Abstract

The application discloses an epoxy anhydride resin capable of repeated VPI impregnation and a formed winding comprising the same, and components of the epoxy anhydride resin comprise, by weight parts, 10-20 parts of a dynamic bond epoxy resin, 30-40 parts of a non-dynamic bond epoxy resin, 40-49 parts of an anhydride curing agent, and 0.01-1 part of a latent curing agent; the dynamic bond epoxy resin is shown as formula I: wherein n>=1; the dynamic bond epoxy resin in the epoxy anhydride resin of the application contains a dynamically reactive ester bond, the dynamically reactive ester bond is distributed in a reticular three-dimensional macromolecular resin generated in a crosslinking and curing reaction in a resin impregnation baking reaction curing stage, and the dynamically reactive ester bond can be degraded in an amine solution by heating, so that the technical problems of the inability of an insulation impregnation resin to be degraded, the difficulty of VPI process verification of a thinned insulation structure of a formed winding and the lossless recovery of an electromagnetic wire are solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of insulation impregnated resin, in particular to a repeatable VPI impregnated epoxy anhydride resin and a formed winding comprising the same. BACKGROUND

[0002] With the rapid development of high-voltage large motors and variable frequency motors, the requirements for insulation materials are gradually increasing. Not only the comprehensive performance such as electrical performance and mechanical performance is required to be excellent, but also the thinning of the insulation structure and the improvement of the electrical strength are required to be higher.

[0003] At present, the single-side insulation thickness of 10kV high-voltage motor has been thinned to 1.8mm, and further thinned to 1.6mm or even 1.4mm, and its processability still needs to be verified. As a thermosetting resin, the formed winding after completing VPI impregnation and baking and curing, if the insulation performance cannot meet the requirements, the winding has to be violently disassembled to recover the electromagnetic wire, causing problems such as long manufacturing period and huge loss.

[0004] Therefore, it is necessary to provide a technical solution to solve the problems that the existing insulation impregnated resin cannot be degraded, the VPI processability verification of the thinned insulation structure of the formed winding is difficult, and the electromagnetic wire is difficult to recover. SUMMARY

[0005] Therefore, the present application provides a repeatable VPI impregnated epoxy anhydride resin and a formed winding comprising the same, to solve the technical problems of how to overcome the degradation of the insulation impregnated resin, the difficulty of VPI processability verification of the thinned insulation structure of the formed winding, and the lossless recovery of the electromagnetic wire.

[0006] To achieve the above technical purposes, the present application adopts the following technical solutions:

[0007] In a first aspect, the present application provides a repeatable VPI impregnated epoxy anhydride resin, which comprises, by weight, 10-20 parts of dynamic bond epoxy resin, 30-40 parts of non-dynamic bond epoxy resin, 40-49 parts of anhydride curing agent, and 0.01-1 parts of latent curing agent.

[0008] Formula I, wherein n≥1.

[0009] Preferably, the non-dynamic bond epoxy resin includes one or more of bisphenol F type epoxy resin and bisphenol A type epoxy resin.

[0010] Preferably, the anhydride curing agent includes one or more of tung oil anhydride, methylhexahydrophthalic anhydride, methyl nadic anhydride, and hydrogenated methyl nadic anhydride.

[0011] Preferably, the latent curing agent comprises one or more of zinc acetate, zinc naphthenate, zinc isooctoate, chromium acetylacetonate, boron trifluoride ethylamine.

[0012] Preferably, the dynamic bond epoxy resin is prepared by using bisphenol A and malonic acid as raw materials, tetrabutyl titanate as catalyst, heating to 120-200℃ for 4-10h, washing with water to neutral, then adding epoxy chloropropane under the catalysis of NaOH, heating to 100-110℃ for 5-12h, and washing with water to neutral.

[0013] In the second aspect, the application provides a shaped winding, comprising electromagnetic wire, mica tape, alkali-free glass fiber tape, low-resistance tape, high-resistance tape, and repeatable VPI impregnated epoxy anhydride resin.

[0014] In the third aspect, the application provides a preparation method of the shaped winding, comprising the following steps:

[0015] S1. Using three parallel winding and / or half-lap winding process, the winding matrix is prepared by using electromagnetic wire, mica tape, alkali-free glass fiber tape, low-resistance tape, and high-resistance tape as raw materials;

[0016] S2. The winding matrix is placed in a vacuum environment, then the winding matrix is pressurized and impregnated in the repeatable VPI impregnated epoxy anhydride resin, and then dried and cured to obtain the shaped winding.

[0017] Preferably, in step S2, the vacuum degree of the vacuum environment is 50-60Pa, and the standing time is 5-7h; the pressure of the pressurized impregnation is 0.5-0.6Mpa, and the pressurized impregnation time is 7-10h; the curing temperature is 150-170℃, and the curing time is 12-16h.

[0018] In the fourth aspect, the application provides a method for recycling electromagnetic wire of the shaped winding, comprising the following steps: impregnating the shaped winding in an amine solution and heating to degrade to obtain the recycled electromagnetic wire.

[0019] Preferably, the heating degradation temperature is 80-150℃, and the time is 1-24h.

[0020] The beneficial effects of the present application are as follows: the dynamic bond epoxy resin in the epoxy anhydride resin of the present application contains a dynamic reaction active ester bond, which is distributed in the reticular three-dimensional macromolecular resin generated by the crosslinking and curing reaction in the impregnation resin baking reaction curing stage, and has the characteristics of high bonding strength, low dielectric loss factor and good heat resistance during normal operation of the motor; when the performance of the winding impregnated by VPI, such as partial discharge and leakage current, cannot meet the requirements during the process verification and maintenance stage, the winding can be immersed in an alkaline amine degradation solution to achieve the effect of decomposition, the electromagnetic wire can be taken out intact, the formed winding is re-wrapped with mica tape, and VPI impregnation is performed again, thereby effectively solving the problem that the existing formed winding cannot be repeatedly VPI impregnated and can only be damaged to cause long manufacturing cycle and great loss during the process verification and maintenance stages. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical scheme and advantages of the present application clearer, the present application is further described in detail below with examples. It should be understood that the specific examples described herein are only used to explain the present application and do not limit the present application.

[0022] The present application provides an epoxy anhydride resin which can be repeatedly VPI impregnated, and the components thereof comprise, by weight fraction: 10-20 parts of a dynamic bond epoxy resin, 30-40 parts of a non-dynamic bond epoxy resin, 40-49 parts of an anhydride curing agent, and 0.01-1 part of a latent curing agent; the dynamic bond epoxy resin is shown as formula I:

[0023] Formula I, wherein n≥1.

[0024] In the present application, the dynamic bond epoxy resin can exist stably in the environment of normal temperature and normal pressure, but can be degraded and recovered when exposed to external stimuli such as temperature, chemicals or photolysis; the dynamic bond epoxy resin of the present application will undergo ester exchange reaction and Diels-Alder reaction after heating; the dynamic bond epoxy resin of the present application has sufficient ester bonds, and the molecular weight decreases during degradation, which can reduce the mechanical strength and is beneficial to the decomposition of the epoxy anhydride resin.

[0025] In some embodiments, the non-dynamic bond epoxy resin comprises one or more of bisphenol F type epoxy resin and bisphenol A type epoxy resin.

[0026] In some embodiments, the anhydride curing agent comprises one or more of tung oil anhydride, methylhexahydrophthalic anhydride, methyl nadic anhydride and hydrogenated methyl nadic anhydride.

[0027] In some embodiments, the latent curing agent comprises one or more of zinc acetate, zinc naphthenate, zinc isooctoate, chromium acetylacetone and boron trifluoride ethylamine.

[0028] In some embodiments, the method for preparing the dynamic key epoxy resin is as follows: 1.05 mol of bisphenol A and 1 mol of malonic acid are put into a three-necked flask, tetrabutyl titanate is added as a catalyst, heated to 120-200°C for 4-10 h, washed with water until neutral, 2 mol of epichlorohydrin is added, heated to 100-110°C for 5-12 h under the catalysis of NaOH, and then used after washing with water until neutral.

[0029] In a second aspect, the application provides a shaped winding, comprising an electromagnetic wire, a mica tape, an alkali-free glass fiber tape, a low-resistance tape, a high-resistance tape, and a repeatable VPI impregnated epoxy anhydride resin.

[0030] In some embodiments, the mica tape comprises one or more of commercially available glass cloth reinforced little rubber powder mica tape, polyester film reinforced little rubber powder mica tape, and polyimide film reinforced little rubber powder mica tape, and the mica tape further comprises an epoxy accelerator, which includes but is not limited to one or more of zinc acetate, zinc naphthenate, zinc isooctoate, chromium acetylacetone, and boron trifluoride ethylamine. The mica tape is composed of mica paper, adhesive, and reinforcing materials (glass cloth, film, etc.), and the accelerator is contained in the adhesive.

[0031] In a third aspect, the application provides a method for preparing a shaped winding, comprising the following steps:

[0032] S1. Using a three-strand parallel winding and / or a half-lap winding process, a winding matrix is prepared from an electromagnetic wire, a mica tape, an alkali-free glass fiber tape, a low-resistance tape, and a high-resistance tape as raw materials;

[0033] S2. The winding matrix is placed in a vacuum environment, then the winding matrix is pressure impregnated in a repeatable VPI impregnated epoxy anhydride resin, and then dried and cured to obtain a shaped winding.

[0034] In some embodiments, in step S2, the vacuum degree of the vacuum environment is 50-60 Pa, and the standing time is 5-7 h; the pressure impregnation pressure is 0.5-0.6 MPa, and the pressure impregnation time is 7-10 h; the curing temperature is 150-170°C, and the curing time is 12-16 h. The three-strand parallel winding and half-lap winding process is a means known to those skilled in the art.

[0035] The dynamic key epoxy resin of the present application contains dynamic covalent bonds. During the impregnation resin baking reaction curing stage, the dynamic reactive ester bonds are distributed in the crosslinked curing reaction to form a reticular three-dimensional macromolecular resin, which has the characteristics of high bonding strength, low dielectric loss factor and good heat resistance during normal operation of the motor. When the performance of the winding impregnated by VPI, such as partial discharge and leakage current, cannot meet the requirements during the process verification stage, the winding can be immersed in an amine degradation solution to achieve the effect of decomposition. The electromagnetic wire can be taken out intact, and the formed winding can be re-wrapped with mica tape and impregnated by VPI again, effectively solving the problem that the existing formed winding cannot be repeatedly impregnated by VPI and can only be damaged to cause long manufacturing cycle and large loss during the process verification stage and the repair stage.

[0036] In a fourth aspect, the present application provides a method for recycling electromagnetic wire from a formed winding, comprising the following steps: immersing the formed winding in an amine solution and heating to degrade, thereby obtaining the recycled electromagnetic wire.

[0037] In the amine solution, the epoxy anhydride resin of the present application is heated and degraded to lose viscosity and strength, and the electromagnetic wire can be directly taken out for recycling without violent disassembly of the formed winding. The amine solution includes but is not limited to one or more of N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, and N-methyl pyrrolidone.

[0038] Preferably, the heating and degradation temperature is 80-150℃, and the time is 1-24h.

[0039] The present application is further illustrated by specific examples below.

[0040] Raw material preparation

[0041] Dynamic key epoxy resin: 1.05 mol of bisphenol A and 1 mol of malonic acid are put into a three-necked flask, titanium tetrabutoxide is added as a catalyst, heated to 120℃-200℃ for 4-10h, washed with water until neutral, 2 mol of epoxy chloropropane is added, heated to 100-110℃ for 5-12h under the catalysis of NaOH, and then washed with water until neutral for standby use.

[0042] Example 1

[0043] An epoxy anhydride resin that can be repeatedly impregnated by VPI, which contains the following components by weight parts: 15 parts of dynamic key epoxy resin, 40 parts of E51 epoxy resin, 44 parts of methylhexahydrophthalic anhydride, and 1 part of zinc acetate; the dynamic key epoxy resin is shown in formula I:

[0044] Formula I, wherein n=2.

[0045] Example 2

[0046] A repeatable VPI impregnated epoxy anhydride resin, components of which comprise, by weight parts: 20 parts of dynamic bond epoxy resin, 35 parts of E44 epoxy resin, 44.5 parts of tung oil anhydride, 0.5 parts of zinc naphthenate; the dynamic bond epoxy resin is shown as formula I:

[0047] Formula I, wherein n = 2.

[0048] Example 3

[0049] A repeatable VPI impregnated epoxy anhydride resin, components of which comprise, by weight parts: 10 parts of dynamic bond epoxy resin, 40 parts of E51 epoxy resin, 49 parts of methyl hexahydrophthalic anhydride, 1 part of zinc acetate; the dynamic bond epoxy resin is shown as formula I:

[0050] Formula I, wherein n = 2.

[0051] Example 4

[0052] A repeatable VPI impregnated epoxy anhydride resin, components of which comprise, by weight parts: 17 parts of dynamic bond epoxy resin, 38 parts of F170 epoxy resin, 44.5 parts of methyl nadic anhydride, 0.05 parts of zinc acetate; the dynamic bond epoxy resin is shown as formula I:

[0053] Formula I, wherein n = 2.

[0054] Example 5

[0055] A shaped winding, raw materials for preparation include polyimide film sintered wire, glass cloth reinforced mica tape with little glue powder, polyester film reinforced mica tape with little glue powder, polyimide film reinforced mica tape with little glue powder, low resistance tape, high resistance tape, the repeatable VPI impregnated epoxy anhydride resin prepared in example 1; the preparation steps are as follows:

[0056] S1. Three MYFB-2 polyimide film sintered wires are wound together to make a coil, and 7 layers of glass cloth reinforced mica tape with little glue powder are sequentially half-laminated, 1 layer of low resistance tape is half-laminated in a straight line, and 1 layer of high resistance tape is half-laminated with an overlap of about 20 cm to make a winding base;

[0057] S2. The winding base is pre-baked and cooled to 45℃, then placed in a varnish tank, vacuumized to below 50Pa and maintained for 6h; the repeatable VPI impregnated epoxy anhydride resin is input into the varnish tank, pressurized to 0.5Mpa~0.6Mpa and maintained for 10h; the impregnated shaped winding is placed in an oven, heated to 160℃ and maintained for 14h for curing, and the shaped winding is obtained.

[0058] Example 6

[0059] A shaped winding, other contents are same with embodiment 5, the difference is that, in step S1, after three MYFB-2 polyimide film sintering wires are parallel-wound to make a coil, 4 layers of glass cloth reinforced little rubber powder mica tape and 3 layers of polyester film reinforced little rubber powder mica tape are sequentially semi-laminated and wrapped.

[0060] Example 7

[0061] A shaped winding, other contents are same with embodiment 5, the difference is that, in step S1, after three MYFB-2 polyimide film sintering wires are parallel-wound to make a coil, 3 layers of glass cloth reinforced little rubber powder mica tape and 4 layers of polyester film reinforced little rubber powder mica tape are sequentially semi-laminated and wrapped.

[0062] Example 8

[0063] A shaped winding, other contents are same with embodiment 5, the difference is that, in step S1, after three MYFB-2 polyimide film sintering wires are parallel-wound to make a coil, 4 layers of glass cloth reinforced little rubber powder mica tape and 3 layers of polyimide film reinforced little rubber powder mica tape are sequentially semi-laminated and wrapped.

[0064] Example 9

[0065] A shaped winding, other contents are same with embodiment 5, the difference is that, in step S1, after three MYFB-2 polyimide film sintering wires are parallel-wound to make a coil, 3 layers of glass cloth reinforced little rubber powder mica tape and 4 layers of polyimide film reinforced little rubber powder mica tape are sequentially semi-laminated and wrapped.

[0066] Comparative Example 1

[0067] An epoxy anhydride resin, the components are as follows in parts by weight: 50 parts of E51 epoxy resin, 49.8 parts of methylhexahydrophthalic anhydride, and 0.2 parts of zinc acetate.

[0068] Test and evaluation

[0069] The epoxy anhydride resins provided in examples 1-4 and comparative example 1 are mixed and cured at 150℃ for 6 hours, the conventional performance of the obtained resins is tested, and the degradability is evaluated at 130℃ with an amine solution, and the results are shown in Table 1.

[0070] Table 1 Test results of the performance of the epoxy anhydride resin

[0071]

[0072] The above results show that the higher the content of the dynamic bond epoxy resin, the shorter the time required for degradation in the amine solution, the epoxy anhydride impregnating resin without dynamic bond epoxy resin does not have degradability, and the epoxy anhydride resin of example 1 of the present application has better comprehensive performance.

[0073] The insulation structure of the formed winding of examples 5-9 was arranged, as shown in table 2.

[0074] Table 2: Production method of the insulation structure of the formed winding of examples 5-9

[0075]

[0076] The performance indexes of the formed winding of examples 5-9 were tested, and the results are shown in table 3.

[0077] Table 3: Test results of the performance of the formed winding of examples 5-9

[0078]

[0079] As can be seen from examples 5-9, for the conventional 10kV formed winding insulation structure, the formed winding impregnated by example 1 can meet the performance requirements, and can be degraded in the amine solution to be taken out without damage. When the process and insulation structure design cannot meet the performance requirements, the electromagnetic wire can be taken out without damage, the formed winding is re-made and VPI impregnated again, effectively solving the problem that the existing formed winding cannot be repeatedly VPI impregnated in the process verification stage and repair stage, and can only be damaged to cause long manufacturing cycle and large loss.

[0080] The above is only a preferred specific embodiment of the present application, but the protection scope of the present application is not limited thereto, any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the present application, which should be covered within the protection scope of the present application.

Claims

1. A repeatable VPI-impregnated epoxy anhydride resin characterized in that, The components comprise, by weight parts: 10-20 parts of dynamic bond epoxy resin, 30-40 parts of non-dynamic bond epoxy resin, 40-49 parts of anhydride curing agent, 0.01-1 part of latent curing agent; the dynamic bond epoxy resin is shown as formula I: Formula I, wherein n >

1.

2. The repeatable VPI impregnated epoxy anhydride resin of claim 1, wherein, The non-dynamic bond epoxy resin comprises one or more of bisphenol F type epoxy resin and bisphenol A type epoxy resin.

3. The repeatable VPI impregnated epoxy anhydride resin of claim 1, wherein, The anhydride curing agent comprises one or more of tung oil anhydride, methylhexahydrophthalic anhydride, methyl nadic anhydride and hydrogenated methyl nadic anhydride.

4. The repeatable VPI impregnated epoxy anhydride resin of claim 1, wherein, The latent curing agent comprises one or more of zinc acetate, zinc naphthenate, zinc isooctoate, chromium acetylacetone and boron trifluoride ethylamine.

5. The repeatable VPI impregnated epoxy anhydride resin of claim 1, wherein, The preparation method of the dynamic bond epoxy resin is as follows: bisphenol A and malonic acid are used as raw materials, tetrabutyl titanate is used as catalyst, heating is carried out at 120-200 DEG C for 4-10 h, water washing is carried out until neutral, then epoxy chloropropane is added under the catalysis of NaOH, heating is carried out at 100-110 DEG C for 5-12 h, and water washing is carried out until neutral, thereby obtaining the dynamic bond epoxy resin.

6. A shaped winding, characterized by The electromagnetic wire, the mica tape, the non-alkali glass fiber tape, the low-resistance tape, the high-resistance tape and the repeatable VPI impregnated epoxy anhydride resin as claimed in any one of claims 1-5.

7. A method of manufacturing a shaped winding as claimed in claim 6, characterized in that, The method comprises the following steps: S1. using three parallel winding and / or half-lap winding process, using electromagnetic wire, mica tape, non-alkali glass fiber tape, low-resistance tape and high-resistance tape as raw materials, preparing winding matrix; S2. placing the winding matrix in a vacuum environment, then pressurizing and impregnating the winding matrix in the repeatable VPI impregnated epoxy anhydride resin, and then drying and curing, thereby obtaining the shaped winding.

8. The method of manufacturing a shaped winding of claim 7, wherein, In step S2, the vacuum degree of the vacuum environment is 50-60 Pa, and the standing time is 5-7 h; the pressure of the pressurized impregnation is 0.5-0.6 MPa, and the pressurized impregnation time is 7-10 h; the curing temperature is 150-170 DEG C, and the curing time is 12-16 h.

9. A method of recovering an electromagnetic wire using the shaped winding according to claim 6, characterized by, The method comprises the following steps: The shaped winding is impregnated in an amine solution and heated for degradation, thereby obtaining recycled electromagnetic wire.

10. The method of claim 9, wherein, The heating degradation temperature is 80-150 DEG C, and the time is 1-24 h.

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