Insulating impregnating varnish

Abstract

The invention discloses insulating impregnating varnish. The insulating impregnating varnish comprises a first component and a second component, the first component comprises an epoxy compound, polyesterimide resin and a cross-linking agent, and the second component comprises a curing agent; the polyesterimide resin is prepared from the following raw materials: iminodiacetic acid dialkyl ester, unsaturated dibasic acid, saturated dibasic anhydride, amino-containing aromatic dibasic acid and a monohydric alcohol end-capping reagent, high-content and uniformly-distributed imino groups can be obtained in a main chain of the polyesterimide resin, and more uniform cross-linking sites are provided; compared with the prior art, the insulating impregnating varnish provided by the invention has the advantages that the insulating impregnating varnish is high in varnish hanging amount and has excellent electromechanical properties, heat resistance, degradation resistance, weather resistance and the like, and more chemical bonds can be formed among molecular chains of polyester-imide resin, and the imino group promotes double-bond free radical polymerization and ring-opening polymerization reaction of epoxy groups at the same time.

Description

Technical Field

[0001] The invention relates to the field of electronics and electrical appliances, in particular to a resin material used in the field of electronics and electrical appliances, and specifically to an insulating impregnating varnish. Background Art

[0002] With the continuous upgrading of products such as generators and special motors, the increase in rated voltage and power density, the operating environment is becoming increasingly harsh, which accelerates the aging process of insulation materials and their systems, resulting in early electrical breakdown and failure. In order to extend the service life of equipment such as generators and special motors, materials such as impregnating resins with high paint hanging amount, high breakdown strength, low dielectric loss, high bonding strength and certain flame retardant properties must be used. These materials can effectively protect the wires and components inside the motor to prevent chemical corrosion and physical wear due to high temperature, high pressure and harsh environment, thereby ensuring the stable operation and long-term reliability of the motor. Unsaturated polyester imide resin is composed of unsaturated polyester polymers containing imide structural units. Its molecular chain is characterized by the presence of imide structure, which gives it good thermal stability and mechanical properties. It is not only used for insulation treatment of motors, but also widely used in the insulation layer of electrical equipment such as transformers, cables, switchgear, etc., to improve the performance and safety of these equipment.

[0003] At present, the main technical approaches for synthesizing unsaturated polyester imine resins include: introducing trimellitic anhydride and diamine in the later stage of unsaturated polyester synthesis, introducing an end-capping agent containing an imine structure (such as the reaction product of phthalic anhydride and monoethanolamine) in the synthesis process of unsaturated polyester, and using isocyanate technical solutions, etc. However, these methods usually result in low imino content, uneven distribution or difficulty in control, which in turn makes the synthesized unsaturated polyester imine resin insufficient in performance stability, especially in terms of strength, heat resistance and flame retardancy, making it difficult to meet further product development needs and difficult to prepare high-quality insulating impregnation varnishes.

[0004] It should be noted that the information disclosed in the above background technology section is only used to understand the background of the present application, so the background technology section of the present invention may contain background information about the problem or environment of the present invention, but not necessarily describe the prior art. Therefore, the content contained in the background technology section is not an admission of the applicant to the prior art. Summary of the invention

[0005] The object of the present invention is to overcome one or more deficiencies in the prior art and to provide an improved insulating impregnating varnish which can at least solve one problem in the prior art.

[0006] Furthermore, the insulating impregnating varnish of the present invention is stable at room temperature, can be cured quickly under medium and high temperature conditions, and has good flow permeability. The cured paint film not only has a large amount of paint, but also has excellent physical properties, such as toughness. It also exhibits excellent electromechanical properties, heat resistance, degradation resistance, and weather resistance.

[0007] In order to achieve the above object, a technical solution adopted by the present invention is:

[0008] An insulating impregnating varnish comprising a first component and a second component;

[0009] The first component comprises an epoxy compound, a polyester imine resin, and a cross-linking agent, and the second component comprises a curing agent;

[0010] The raw materials of the polyester imide resin include:

[0011] (a) Compound represented by formula (I)

[0012] In which R1 and R2 are independently C 1-8 Alkylene;

[0013] (b) unsaturated dibasic acids;

[0014] (c) saturated dibasic acid anhydrides;

[0015] (d) Compound represented by formula (II)

[0016] In which R3 and R4 are independently selected from substituted C 6-12 The aromatic ring, the substituents used include carboxyl, and selected from H, C 1-6 Alkyl and C 1-6 one or more of the alkoxy groups;

[0017] (e) Compound represented by formula (III)

[0018] In which one of R5 and R6 is a hydroxyl group, and the other is selected from H, C 1-6 Alkyl or C 1-6 Alkoxy.

[0019] In some embodiments of the present invention, the feed mass ratio of the first component to the second component is 100:25-35.

[0020] In some embodiments of the present invention, the curing temperature of the insulating impregnating varnish is 100-180°C.

[0021] In some embodiments of the present invention, the mass ratio of the epoxy compound, the polyesterimine resin and the cross-linking agent is 50-70:90-110:20-40, further 55-65:95-105:25-35.

[0022] In some embodiments of the present invention, the epoxy compound is an alicyclic epoxy resin.

[0023] According to some preferred aspects of the present invention, the epoxy compound has a structure shown in the following formula (IV):

[0024]

[0025] In formula (IV), R a Selected from C 1-6 Alkylene or C containing heteroatoms 1-6 Alkylene, R b Selected from C 1-6 Alkylene, C 1-6 Alkylene ester group, C 1-6 Alkylene ester group C 1-6 Alkylene, the heteroatom is O, N or S, or R b Does not exist.

[0026] In the present invention, C 1-6 The alkylene group may be methylene, ethylene, propylene, butylene or the like.

[0027] In the present invention, C 1-6 The alkylene ester group may be a methylene ester group, an ethylene ester group, a propylene ester group, a butylene ester group, or the like. 1-6 Alkylene ester group C 1-6 The alkylene group may be methylene ester methylene, ethylene ester methylene, ethylene ester ethylene, propylene ester methylene, propylene ester propylene, butylene ester methylene, methylene ester butylene, and the like.

[0028] In some embodiments of the present invention, the molecular weight of the epoxy compound is less than or equal to 500.

[0029] According to some specific aspects of the present invention, the epoxy compound is 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexylcarboxylate and / or bis((3,4-epoxycyclohexyl)methyl)adipate.

[0030] In some embodiments of the present invention, the cross-linking agent contains both double bonds and epoxy groups.

[0031] According to some preferred aspects of the present invention, the cross-linking agent has a structure as shown in the following formula (V):

[0032]

[0033] In formula (V), R c Selected from C 1-6 Alkylene, carbonyl, C 1-6 Alkylenecarbonyl, C 1-6 AlkylenecarbonylC 1-6 Alkylene, phenyl C 1-6 Alkylene, C 1-6 Alkylenephenyl C 1-6 Alkylene, R d Select from H or C 1-6 alkyl.

[0034] In the present invention, C 1-6 The alkylenecarbonyl group may be methylenecarbonyl, ethylenecarbonyl, propylenecarbonyl, butylenecarbonyl, pentylenecarbonyl, etc.; C 1-6 AlkylenecarbonylC 1-6 The alkylene group may be methylenecarbonylmethylene, methylenecarbonylethylene, ethylenecarbonylethylene, methylenecarbonylpropylene, ethylenecarbonylpropylene, etc.; phenyl C 1-6 The alkylene group may be phenylmethylene, phenylethylene, phenylpropylene, phenylbutylene, phenylpentylene, etc.; C 1-6 Alkylenephenyl C 1-6 The alkylene group may be methylenephenylmethylene, methylenephenylethylene, methylenephenylpropylene, methylenephenylbutylene, methylenephenylpentylene, etc.; C 1-6 The alkyl group may be methyl, ethyl, propyl, butyl or the like.

[0035] According to some specific aspects of the present invention, the cross-linking agent is a combination of one or more selected from allyl glycidyl ether, methacrylate glycidyl ether, and 4-vinylbenzyl glycidyl ether.

[0036] In some embodiments of the present invention, the first component further comprises a polymerization inhibitor, and further, the mass ratio of the polymerization inhibitor to the epoxy compound is 0.01-0.4:50-70. Furthermore, the polymerization inhibitor is hydroquinone and / or p-hydroxyanisole.

[0037] In some embodiments of the present invention, the curing agent is an acid anhydride, and further, the acid anhydride is methyltetrahydrophthalic anhydride and / or methylnadic anhydride.

[0038] In some embodiments of the present invention, the second component further comprises an initiator and a accelerator. Further, the initiator comprises a peroxide initiator, and the peroxide initiator comprises dicumyl peroxide and / or 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane.

[0039] Furthermore, the accelerator includes an amine accelerator, and the amine accelerator includes 2,4,6-tris(dimethylaminomethyl)phenol.

[0040] Furthermore, the mass ratio of the acid anhydride, the initiator and the accelerator is 55-65:1.5-3.5:1.5-3.5.

[0041] The present invention also provides a technical solution: a method for preparing the above insulating impregnating varnish, the preparation method comprising:

[0042] Prepare the first component:

[0043] Mix the ingredients in the first component, stir evenly, and filter;

[0044] Prepare the second component:

[0045] Mix the ingredients in the second component, stir well and filter.

[0046] Furthermore, in practical application, the first component and the second component are uniformly mixed and cured. In some embodiments of the present invention, the curing is performed at 130-150° C. for 1-3 hours, and then at 160-180° C. for 4-6 hours.

[0047] In some embodiments of the present invention, during the preparation of the first component, stirring is performed at 50-60° C. Further, the stirring speed is 5000-10000 rpm.

[0048] In some embodiments of the present invention, during the preparation of the second component, stirring is performed at 25-30° C. Further, the stirring speed is 5000-10000 rpm.

[0049] Another technical solution provided by the present invention is a polyester imine resin, wherein the raw materials of the polyester imine resin include:

[0050] (a) Compound represented by formula (I)

[0051] In which R1 and R2 are independently C 1-8 Alkylene;

[0052] (b) unsaturated dibasic acids;

[0053] (c) saturated dibasic acid anhydrides;

[0054] (d) Compound represented by formula (II)

[0055] In which R3 and R4 are independently selected from substituted C 6-12 The aromatic ring, the substituents used include carboxyl, and selected from H, C1-6 Alkyl and C 1-6 one or more of the alkoxy groups;

[0056] (e) Compound represented by formula (III)

[0057] In which one of R5 and R6 is a hydroxyl group, and the other is selected from H, C 1-6 Alkyl or C 1-6 Alkoxy.

[0058] The present invention innovatively introduces the compound represented by formula (I), the compound represented by formula (II) and the compound represented by formula (III) simultaneously during the polymerization process, which not only enables the polyester imine resin of the present invention to obtain high-content and uniformly distributed imine groups in the main chain, provides more and uniform cross-linking sites, and is conducive to miscibility with organic resins such as epoxy, alkyd, and vinyl, but also enables more chemical bonds to be formed between the molecular chains of the polyester imine resin, greatly increasing the filling amount of the formed polymer in the matrix, and enhancing the overall performance of the material. At the same time, the polyester imine resin of the present invention has the advantage of controllable molecular chain length, improved fluidity and permeability, and practice shows that the polyester imine resin of the present invention has relatively excellent mechanical properties, electrical properties, heat resistance and degradation resistance. In addition, when the polyester imine resin of the present invention is used, no toxic or harmful diluents need to be added, which is conducive to the green and environmental protection of product production and use, and can be widely used in the manufacture of glass fiber reinforced plastics, wind turbine blades, and electrical insulation materials.

[0059] According to some preferred aspects of the present invention, the molar ratio of the compound represented by formula (I), the unsaturated dibasic acid, the saturated dibasic acid anhydride, the compound represented by formula (II) and the compound represented by formula (III) is 1:0.3-0.5:0.4-0.6:0.05-0.15:0.05-0.25.

[0060] In some embodiments of the present invention, the method for preparing the compound represented by formula (I) comprises: reacting diethyl iminodiacetate with C 1-8 Alkylene glycol is prepared by transesterification reaction, wherein the C 1-8 The alkylene glycol is selected from the following structures: Furthermore, the C 1-8 The alkylene glycol is preferably 1,2-propylene glycol or neopentyl glycol.

[0061] Furthermore, the embodiment of preparing the compound represented by formula (I) comprises: adding diethyl iminodiacetate, C 1-8Alkylene glycol and catalyst (such as zinc acetate, etc.), open the condensation reflux device, raise the temperature to 120°C, after part of the raw material solid components are dissolved, start stirring, and then slowly raise the temperature to 170-180°C to start ester exchange, reflux reaction for 0.1-2 hours, then remove ethanol by distillation, and the ethanol to be removed and collected reaches more than 99% of the theoretical value, continue heating and control the reaction temperature at 180-205°C, cool to 120°C, filter out solid impurity particles with residual heat through a Buchner funnel, and gradually cool the filtrate to -5~0°C while stirring, and filter out the crystalline product, which is the compound represented by formula (I).

[0062] In some embodiments of the present invention, R1 and R2 are independently selected from:

[0063]

[0064] According to some specific aspects of the present invention, the compound represented by formula (I) can be iminodiacetic acid bis-β-(1,2-propylene glycol), iminodiacetic acid bis-β-(neopentyl glycol), etc.

[0065] In some embodiments of the present invention, the unsaturated dibasic acid includes but is not limited to maleic anhydride and / or fumaric acid.

[0066] In some embodiments of the present invention, the saturated dibasic acid anhydride includes but is not limited to phthalic anhydride and / or methyltetrahydrophthalic anhydride.

[0067] In some embodiments of the present invention, in formula (II), R3 and R4 are independently selected from R7 is selected from H, methyl, ethyl, propyl or methoxy.

[0068] In some embodiments of the present invention, in formula (III), R5 is a hydroxyl group substituted at the para position, and R6 is selected from H, methyl, ethyl, propyl or methoxy.

[0069] According to some specific aspects of the present invention, the compound represented by formula (II) is an aromatic dibasic acid containing an amino group, and may be 4,4'-iminodibenzoic acid.

[0070] According to some specific aspects of the present invention, the compound represented by formula (III) is a monohydric alcohol capping agent, which may be 4-maleimidophenol.

[0071] In some embodiments of the present invention, the raw material of the polyesterimine resin further comprises (f) an esterification catalyst and (g) a polymerization inhibitor. Further, the molar ratio of the esterification catalyst to the compound represented by formula (I) is 0.02-0.08:1, and the amount of the polymerization inhibitor added is 0.05%-0.5% of the total mass of the raw material of the polyesterimine resin.

[0072] Furthermore, the esterification catalyst is a combination of one or more selected from sulfuric acid, p-toluenesulfonic acid, and ion exchange resin, preferably p-toluenesulfonic acid; the inhibitor is a combination of one or more selected from hydroquinone, nitrobenzene, tert-butylcatechol, and p-hydroxyanisole.

[0073] Furthermore, the reaction formula for preparing the compound represented by formula (I) is as follows (the example is given for the compound represented by formula (I) in which R1 and R2 are the same):

[0074]

[0075] The following is an example of the reaction process of polyester imide resin and the structure obtained by the reaction, taking the unsaturated dibasic acid as maleic anhydride (maleic anhydride), the saturated dibasic acid anhydride as phthalic anhydride, the compound represented by formula (II) as 4,4'-iminodibenzoic acid, and the compound represented by formula (III) as 4-maleimidophenol as an example:

[0076]

[0077] Furthermore, when R' is When, an exemplary structure of the polyesterimide resin is as follows:

[0078]

[0079] Furthermore, when R' is When, an exemplary structure of the polyesterimide resin is as follows:

[0080]

[0081] The structure of the polyesterimide resin is only an exemplary structure, which only exemplifies the combination of the raw materials in which the hydroxyl group reacts with the carboxyl group or the acid anhydride to generate the ester group; in the actual reaction process, following the principle of the hydroxyl group reacting with the carboxyl group or the acid anhydride to generate the ester group, the reaction order or combination mode of each compound may be different, which is specifically manifested in that the repeating units where a, b, and c are located may have different combinations. For example, the compound shown in formula (I) can react with maleic anhydride (maleic anhydride), 4,4'-imidodibenzoic acid, or phthalic anhydride. Therefore, there are many situations in the structure after the reaction between them.

[0082] Another technical solution provided by the present invention is a method for preparing the polyesterimide resin described above, the method comprising: mixing the other components of the raw materials of the polyesterimide resin except the polymerization inhibitor, heating under a protective atmosphere, reacting, and selectively removing the generated water at each stage of the reaction, when the acid value reaches 30-40 mgKOH / g, performing vacuum reduced pressure distillation and continuing the reaction, when the acid value decreases to 5-15 mgKOH / g, cooling, adding the polymerization inhibitor, and mixing.

[0083] Furthermore, the protective atmosphere can be formed by introducing nitrogen or an inert gas, wherein the inert gas includes helium, argon, etc.

[0084] Further, the temperature is raised to 110-130° C. under a protective atmosphere.

[0085] Furthermore, the implementation method of preparing the polyesterimide resin includes: mixing the other ingredients of the raw materials of the polyesterimide resin except the polymerization inhibitor, heating to 110-130° C. under a protective atmosphere, starting stirring after some solid components of the raw materials are dissolved, and then slowly heating to 155-175° C. to start generating byproduct water, esterification reflux reaction for 0.1-2 hours, starting distillation and dehydration to carry out esterification condensation, and after the acid value reaches 30-40 mgKOH / g, starting vacuuming and performing reduced pressure distillation to continue the condensation reaction, reacting until the acid value decreases to 5-15 mgKOH / g, cooling to 125-135° C., adding the polymerization inhibitor, stirring, and continuing to cool to below 80° C. to filter and discharge the material to obtain the polyesterimide resin.

[0086] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art:

[0087] The present invention provides a polyester-imide resin with a high imine content, wherein iminodicarboxylic acid is introduced in the polyester synthesis stage to synthesize a main chain type polyester with a high imine content. The polyester-imide resin exhibits uniformly distributed imine groups and can be miscible with a variety of organic resins such as epoxy resins, alkyd resins, and vinyl resins. The high content of imine groups promotes the increase of crosslinking points, so that more chemical bonds can be formed between the polyester-imide resin molecular chains, thereby significantly increasing the filling amount of the polymer in the matrix and enhancing the overall performance of the material. In addition, the molecular chain length of the polyester-imide resin of the present invention can be precisely controlled to improve its fluidity and permeability during use. Based on the preparation of the polyester-imide resin with a high imine content, the present invention adopts a compound of an epoxy compound and a crosslinking agent to successfully prepare an insulating varnish with a high paint hanging amount. This technology realizes the composite cross-linking of polyester imide and epoxy resin, in which the imide group simultaneously promotes the double bond free radical polymerization and the ring-opening polymerization reaction of the epoxy group. The cured polymer paint film shows the structural characteristics of imide-double bond network cross-linking and epoxy ring-opening network cross-linking; the paint film is stable at room temperature, can be quickly cured under medium and high temperature conditions, and has good flow permeability; the cured paint film not only has a large amount of paint, but also has excellent physical properties, such as toughness, it also shows excellent electromechanical properties, heat resistance, degradation resistance and weather resistance. DETAILED DESCRIPTION

[0088] The above scheme is further described below in conjunction with specific embodiments; it should be understood that these embodiments are used to illustrate the basic principles, main features and advantages of the present invention, and the present invention is not limited to the scope of the following embodiments; the implementation conditions adopted in the embodiments can be further adjusted according to specific requirements, and the implementation conditions not specified are usually the conditions in conventional experiments.

[0089] Unless otherwise specified in the following examples, all raw materials are commercially available or prepared by conventional methods in the art.

[0090] The iminodiacetic acid bis-β-(1,2-propylene glycol) used in the following examples was prepared as follows: diethyl iminodiacetate (1 mol), 1,2-propylene glycol (2 mol) and zinc acetate (0.34 g) were added to a 500 mL three-necked flask, the condensing reflux device was opened, the temperature was raised to 120° C., and after most of the solid components of the raw materials were dissolved, stirring was started, and then the temperature was slowly raised to 175° C. to start ester exchange, reflux reaction for 0.5 hours, and then ethanol was removed by distillation. The ethanol to be removed and collected reached more than 99% of the theoretical value, and the reaction temperature was continued to be heated and controlled at 195° C., cooled to 120° C., and the residual heat was used to filter out solid impurity particles with a Buchner funnel. The filtrate was stirred and gradually cooled to -5 to 0° C., and the crystalline product was filtered out for standby use.

[0091] Iminodiacetic acid bis-β-(neopentyl glycol) was prepared as follows: diethyl iminodiacetate (1 mol), neopentyl glycol (2 mol) and zinc acetate (0.4 g) were added to a 500 mL three-necked flask, the condensing reflux device was opened, the temperature was raised to 120° C., and after most of the raw material solid components were dissolved, stirring was started, and then the temperature was slowly raised to 175° C. to start ester exchange, reflux reaction was carried out for 0.5 hours, and then ethanol was removed by distillation, and the ethanol to be removed and collected reached more than 99% of the theoretical value, and the heating was continued and the reaction temperature was controlled at 195° C., and then cooled to 120° C., and the residual heat was used to filter out solid impurity particles with a Buchner funnel, and the filtrate was gradually cooled to -5 to 0° C. under stirring, and the crystallized product was filtered out for standby use.

[0092] Example 1

[0093] This example provides a polyester imine resin and a preparation method thereof. The raw materials of the polyester imine resin include: 281.21 g (1 mol) of iminodiacetic acid di-β-(1,2-propylene glycol), 39.22 g (0.4 mol) of maleic anhydride, 74.06 g (0.5 mol) of phthalic anhydride, 25.72 g (0.1 mol) of 4,4'-iminodibenzoic acid, 9.46 g (0.05 mol) of 4-maleimidophenol, 5.5 g of p-toluenesulfonic acid, and 0.5 g of hydroquinone.

[0094] The preparation method of the polyesterimide resin comprises the following steps: adding raw materials other than hydroquinone into a four-necked flask with a temperature control and stirring device, passing a nitrogen atmosphere for protection, opening a condensation reflux device, heating to 120°C, starting stirring after most of the raw material solid components are dissolved, slowly heating to 165°C to start generating byproduct water, performing esterification reflux reaction for 0.5 hours, starting distillation and dehydration to perform esterification polycondensation, and starting vacuumization to perform reduced pressure distillation to continue polycondensation reaction after the acid value reaches 35 mgKOH / g, reacting until the acid value decreases to 10 mgKOH / g, cooling to 130°C, adding hydroquinone, stirring for 10 minutes, and continuing to cool to below 80°C to filter and discharge the material to obtain the polyesterimide resin.

[0095] In this example, the time for esterification and polycondensation when the acid value reaches 35 mgKOH / g is about 5 hours.

[0096] The average molecular weight of the product was measured by GPC (gel permeation chromatography) and was approximately 1987. The nitrogen content was measured according to GB / T 609-2018 and the imine value (mol / 100g) of the product was approximately 0.262. The crystallinity of the product was measured according to ASTM F2625-2010 and was approximately 67.5%.

[0097] Example 2

[0098] This example provides a polyester imine resin and a preparation method thereof. The raw materials of the polyester imine resin include: 337.21 g (1 mol) of iminodiacetic acid bis-β-(neopentyl glycol), 46.41 g (0.4 mol) of fumaric acid, 74.06 g (0.5 mol) of phthalic anhydride, 25.72 g (0.1 mol) of 4,4'-iminodibenzoic acid, 9.46 g (0.05 mol) of 4-maleimidophenol, 5.5 g of p-toluenesulfonic acid, and 0.5 g of hydroquinone.

[0099] The preparation method is the same as Example 1.

[0100] The average molecular weight of the product measured by GPC (gel permeation chromatography) is about 2037, the nitrogen content is measured according to GB / T 609-2018 and the imine value (mol / 100g) of the product is about 0.231, and the crystallinity of the product is measured according to ASTM F2625-2010 and is about 67.1%.

[0101] Example 3

[0102] This example provides a polyester imine resin and a preparation method thereof. The raw materials of the polyester imine resin include: 281.21 g (1 mol) of iminodiacetic acid di-β-(1,2-propylene glycol), 39.22 g (0.4 mol) of maleic anhydride, 83.09 g (0.5 mol) of methyltetrahydrophthalic anhydride, 25.72 g (0.1 mol) of 4,4'-iminodibenzoic acid, 9.46 g (0.05 mol) of 4-maleimidophenol, 5.5 g of p-toluenesulfonic acid, and 0.5 g of hydroquinone.

[0103] The preparation method is the same as Example 1.

[0104] The average molecular weight of the product measured by GPC (gel permeation chromatography) is about 2000, the nitrogen content is measured according to GB / T 609-2018 and the imine value (mol / 100g) of the product is about 0.264, and the crystallinity of the product is measured according to ASTM F2625-2010 and is about 67.3%.

[0105] Example 4

[0106] This example provides a polyester imine resin and a preparation method thereof. The raw materials of the polyester imine resin include: 337.21 g (1 mol) of iminodiacetic acid bis-β-(neopentyl glycol), 46.41 g (0.4 mol) of fumaric acid, 83.09 g (0.5 mol) of methyltetrahydrophthalic anhydride, 25.72 g (0.1 mol) of 4,4'-iminodibenzoic acid, 9.46 g (0.05 mol) of 4-maleimidophenol, 5.5 g of p-toluenesulfonic acid, and 0.5 g of hydroquinone.

[0107] The preparation method is the same as Example 1.

[0108] The average molecular weight of the product measured by GPC (gel permeation chromatography) is about 2048, the nitrogen content is measured according to GB / T 609-2018 and the imine value (mol / 100g) of the product is about 0.233, and the crystallinity of the product is measured according to ASTM F2625-2010 and is about 67%.

[0109] Comparative Example 1

[0110] This example provides a polyesterimide resin and a preparation method thereof. The raw materials of the polyesterimide resin include: 76.09 g (1 mol) of 1,2-propylene glycol, 104.15 g (1 mol) of neopentyl glycol, 78.44 g (0.8 mol) of maleic anhydride, 177.74 g (1.2 mol) of phthalic anhydride, 19.12 g (0.1 mol) of N-hydroxyethylphthalimide, 11 g of p-toluenesulfonic acid, and 0.5 g of hydroquinone.

[0111] The preparation method is the same as Example 1.

[0112] In this example, the time for esterification and polycondensation when the acid value reaches 35 mgKOH / g is about 13 hours.

[0113] The average molecular weight of the product was measured by GPC (gel permeation chromatography) and was approximately 1574. The nitrogen content was measured according to GB / T 609-2018 and the imine value (mol / 100g) of the product was approximately 0.021. The crystallinity of the product was measured according to ASTM F2625-2010 and was approximately 5.6%.

[0114] Comparative Example 2

[0115] This example provides a polyester imine resin and a preparation method thereof. The raw materials of the polyester imine resin include: 76.09 g (1 mol) of 1,2-propylene glycol, 104.15 g (1 mol) of neopentyl glycol, 92.82 g (0.8 mol) of fumaric acid, 199.42 g (1.2 mol) of methyltetrahydrophthalic anhydride, 19.12 g (0.1 mol) of N-hydroxyethyl phthalimide, 11 g of p-toluenesulfonic acid, and 0.5 g of hydroquinone.

[0116] The preparation method is the same as Example 1.

[0117] The average molecular weight of the product measured by GPC (gel permeation chromatography) is about 1580, the nitrogen content is measured according to GB / T 609-2018 and the imine value (mol / 100g) of the product is about 0.020, and the crystallinity of the product is measured according to ASTM F2625-2010 and is about 6.1%.

[0118] Comparative Example 3

[0119] This example provides a polyester imine resin and a preparation method thereof. The raw materials of the polyester imine resin include: 208.3 g (2 mol) of neopentyl glycol, 133.1 g (1 mol) of iminodiacetic acid, 39.22 g (0.4 mol) of maleic anhydride, 83.09 g (0.5 mol) of methyltetrahydrophthalic anhydride, 25.72 g (0.1 mol) of 4,4'-iminodibenzoic acid, 9.46 g (0.05 mol) of 4-maleimidophenol, 5.5 g of p-toluenesulfonic acid, and 0.5 g of hydroquinone.

[0120] The preparation method is the same as Example 1.

[0121] The average molecular weight of the product was measured by GPC (gel permeation chromatography) and was approximately 1915. The nitrogen content was measured according to GB / T 609-2018 and the imine value (mol / 100g) of the product was approximately 0.193. The crystallinity of the product was measured according to ASTM F2625-2010 and was approximately 51.7%.

[0122] Application Example 1

[0123] This example provides an insulating impregnating varnish, which comprises a first component and a second component;

[0124] In parts by weight, the first component includes 100 parts of the polyester imide resin prepared in Example 1, 60 parts of 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexylcarboxylate, 30 parts of allyl glycidyl ether, and 0.18 parts of hydroquinone;

[0125] In parts by weight, the second component includes 56 parts of methyltetrahydrophthalic anhydride, 2.6 parts of diisopropylbenzene peroxide, and 2.6 parts of 2,4,6-tris(dimethylaminomethyl)phenol;

[0126] The feed mass ratio of the first component to the second component is 190.18:61.2;

[0127] The preparation method of the insulating impregnating varnish comprises:

[0128] Preparation of the first component: adding each component into a stirring device, stirring and mixing at 55° C. and 10,000 rpm for 60 min, filtering, and obtaining the first component;

[0129] Preparation of the second component: Add each component into a stirring device, stir and mix at 25° C. and 10,000 rpm for 60 minutes, and filter to obtain the second component.

[0130] In actual application, the first component is mixed with the second component and cured.

[0131] Application Example 2

[0132] This example provides an insulating impregnating varnish, which comprises a first component and a second component;

[0133] In parts by weight, in the first component, 100 parts of the polyester imide resin prepared in Example 2, 60 parts of bis((3,4-epoxycyclohexyl)methyl)adipate, 25 parts of glycidyl methacrylate, 5 parts of 4-vinylbenzyl glycidyl ether, and 0.18 parts of p-hydroxyanisole;

[0134] In parts by weight, the second component includes 56 parts of methyl nadic anhydride, 2.6 parts of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, and 2.6 parts of 2,4,6-tris(dimethylaminomethyl)phenol;

[0135] The feed mass ratio of the first component to the second component is 190.18:61.2;

[0136] The rest is the same as Application Example 1.

[0137] Application Example 3

[0138] This example provides an insulating dipping varnish, which comprises a first component and a second component;

[0139] In parts by weight, in the first component, 100 parts of the polyester imide resin prepared in Example 3, 60 parts of 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexylcarboxylate, 30 parts of glycidyl methacrylate, and 0.18 parts of hydroquinone;

[0140] In parts by weight, the second component includes 56 parts of methyl nadic anhydride, 2.6 parts of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, and 2.6 parts of 2,4,6-tris(dimethylaminomethyl)phenol;

[0141] The feed mass ratio of the first component to the second component is 190.18:61.2;

[0142] The rest is the same as Application Example 1.

[0143] Application Example 4

[0144] This example provides an insulating dipping varnish, which comprises a first component and a second component;

[0145] In parts by weight, in the first component, 100 parts of the polyester imine resin prepared in Example 4, 60 parts of bis((3,4-epoxycyclohexyl)methyl)adipate, 25 parts of allyl glycidyl ether, 5 parts of 4-vinylbenzyl glycidyl ether, and 0.18 parts of p-hydroxyanisole;

[0146] In terms of weight, the second component includes 56 parts of methyl nadic anhydride, 2.6 parts of dicumyl peroxide, and 2.6 parts of 2,4,6-tris(dimethylaminomethyl)phenol;

[0147] The feed mass ratio of the first component to the second component is 190.18:61.2;

[0148] The rest is the same as Application Example 1.

[0149] Application Example 5

[0150] This example provides an insulating dipping varnish, which comprises a first component and a second component;

[0151] In parts by weight, in the first component, 50 parts of the polyester imine resin prepared in Example 1, 50 parts of the polyester imine resin prepared in Example 2, 30 parts of 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexylcarboxylate, 30 parts of bis((3,4-epoxycyclohexyl)methyl)adipate, 15 parts of allyl glycidyl ether, 15 parts of glycidyl methacrylate, 0.09 parts of hydroquinone, and 0.09 parts of p-hydroxyanisole;

[0152] In parts by weight, the second component includes 28 parts of methyltetrahydrophthalic anhydride, 28 parts of methylnadic anhydride, 1.3 parts of dicumyl peroxide, 1.3 parts of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, and 2.6 parts of 2,4,6-tris(dimethylaminomethyl)phenol;

[0153] The feed mass ratio of the first component to the second component is 190.18:61.2;

[0154] The rest is the same as Application Example 1.

[0155] Application Example 6

[0156] This example provides an insulating dipping varnish, which comprises a first component and a second component;

[0157] In parts by weight, in the first component, 50 parts of the polyester imine resin prepared in Example 3, 50 parts of the polyester imine resin prepared in Example 4, 30 parts of 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexylcarboxylate, 30 parts of bis((3,4-epoxycyclohexyl)methyl)adipate, 10 parts of allyl glycidyl ether, 15 parts of methacrylate glycidyl ether, 5 parts of 4-vinylbenzyl glycidyl ether, 0.09 parts of hydroquinone, and 0.09 parts of p-hydroxyanisole;

[0158] In parts by weight, the second component includes 28 parts of methyltetrahydrophthalic anhydride, 28 parts of methylnadic anhydride, 1.3 parts of dicumyl peroxide, 1.3 parts of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, and 2.6 parts of 2,4,6-tris(dimethylaminomethyl)phenol;

[0159] The feed mass ratio of the first component to the second component is 190.18:61.2;

[0160] The rest is the same as Application Example 1.

[0161] Application Comparative Example 1

[0162] This example provides an insulating impregnating varnish, which is basically the same as Application Example 6, with the only difference being that "10 parts of allyl glycidyl ether, 15 parts of methacrylate glycidyl ether, and 5 parts of 4-vinylbenzyl glycidyl ether" are replaced with 30 parts of vinyltoluene.

[0163] Application Comparative Example 2

[0164] This example provides an insulating impregnation varnish, which is basically the same as Application Example 6, except that "50 parts of the polyesterimide resin prepared in Example 3 and 50 parts of the polyesterimide resin prepared in Example 4" are replaced with 100 parts of the polyesterimide resin prepared in Comparative Example 1.

[0165] Application Comparative Example 3

[0166] This example provides an insulating impregnation varnish, which is basically the same as Application Example 6, except that "50 parts of the polyesterimide resin prepared in Example 3 and 50 parts of the polyesterimide resin prepared in Example 4" are replaced with 100 parts of the polyesterimide resin prepared in Comparative Example 2.

[0167] Application Comparative Example 4

[0168] This example provides an insulating impregnation varnish, which is basically the same as Application Example 6, with the only difference being that "50 parts of the polyesterimide resin prepared in Example 3 and 50 parts of the polyesterimide resin prepared in Example 4" are replaced with 100 parts of the polyesterimide resin prepared in Comparative Example 3.

[0169] Performance Testing

[0170] The following performance tests were performed on the insulating impregnating varnishes obtained in the above-mentioned application examples 1-6 and the application comparison examples 1-4. The specific results are shown in Table 1-2.

[0171] Curing conditions during testing: 140±2℃ for 2h, then curing and drying at 170±2℃ for 5h.

[0172] The test standard for paint load (g) (spiral coil method) is GB / T 15022.2-2017; the test standard for bonding strength (N) (twisted coil method) is GB / T 15022.2-2017; the test standard for heat resistance grade (℃) temperature index TI is GB / T11026.1-2016; the test standard for hot dielectric loss (%) 50Hz, 180±2℃ is GB / T 15022.2-2017; the test standard for electrical strength, paint cake method 23±2℃ (MV / m) is GB / T 15022.2-2017; the test standard for electrical strength 23±2℃ (MV / m) after 6 days of alternating damp heat test is GB / T 2423.4-2008; the test standard for rotational viscosity 25℃ (mPa·s) is GB / T 15022.2-2017.

[0173] Table 1

[0174]

[0175] Table 2

[0176]

[0177] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with the technology to understand the content of the present invention and implement it accordingly, and they cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

[0178] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

Claims

1. An insulating impregnating varnish, characterized in that: The insulating impregnating varnish comprises a first component and a second component; The first component comprises an epoxy compound, a polyester imine resin, and a cross-linking agent, and the second component comprises a curing agent; The raw materials of the polyester imide resin include: (a) Compound represented by formula (I) In formula (I), R1 and R2 are independently C 1-8 Alkylene; (b) unsaturated dibasic acids; (c) saturated dibasic acid anhydrides; (d) Compound represented by formula (II) In formula (II), R3 and R4 are independently selected from substituted C 6-12 The aromatic ring, the substituents used for substitution include carboxyl, and selected from H, C 1-6 Alkyl and C 1-6 one or more of the alkoxy groups; (e) Compound represented by formula (III) In formula (III), one of R5 and R6 is a hydroxyl group, and the other is selected from H, C 1-6 Alkyl or C 1-6 Alkoxy.

2. The insulating impregnating varnish according to claim 1, characterized in that: The mass ratio of the first component to the second component is 100:25-35; and / or the curing temperature of the insulating impregnating varnish is 100-180°C.

3. The insulating impregnating varnish according to claim 1, characterized in that: The feed mass ratio of the epoxy compound, the polyesterimide resin and the crosslinking agent is 50-70:90-110:20-40; and / or the epoxy compound is an alicyclic epoxy resin; and / or the crosslinking agent contains double bonds and epoxy groups at the same time.

4. The insulating impregnating varnish according to claim 1, characterized in that: The epoxy compound has a structure shown in the following formula (IV): In formula (IV), R a Selected from C 1-6 Alkylene or C containing heteroatoms 1-6 Alkylene; R b Selected from C 1-6 Alkylene, C 1-6 Alkylene ester group, C 1-6 Alkylene ester group C 1-6 Alkylene, the heteroatom is O, N or S, or R b Does not exist.

5. The insulating impregnating varnish according to claim 1, characterized in that: The molecular weight of the epoxy compound is less than or equal to 500.

6. The insulating impregnating varnish according to claim 1, characterized in that: The cross-linking agent has a structure as shown in the following formula (V): In formula (V), R c Selected from C 1-6 Alkylene, carbonyl, C 1-6 Alkylenecarbonyl, C 1-6 AlkylenecarbonylC 1-6 Alkylene, phenyl C 1-6 Alkylene, C 1-6 Alkylenephenyl C 1-6 Alkylene, R d Select from H or C 1-6 alkyl.

7. The insulating impregnating varnish according to claim 1, characterized in that: The epoxy compound is 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexylcarboxylate and / or bis((3,4-epoxycyclohexyl)methyl)adipate; and / or the crosslinking agent is a combination of one or more selected from allyl glycidyl ether, methacrylate glycidyl ether, and 4-vinylbenzyl glycidyl ether; and / or the first component further comprises an inhibitor.

8. The insulating impregnating varnish according to claim 1, characterized in that: The molar ratio of the compound represented by formula (I), the unsaturated dibasic acid, the saturated dibasic acid anhydride, the compound represented by formula (II) and the compound represented by formula (III) is 1: 0.3-0.5: 0.4-0.6: 0.05-0.15: 0.05-0.25; and / or, the preparation method of the compound represented by formula (I) comprises: reacting diethyl iminodiacetate with C 1-8 Alkylene glycol is prepared by transesterification reaction, wherein the C 1-8 The alkylene glycol is selected from the following structures:

9. The insulating impregnating varnish according to claim 1, characterized in that: R1, R2 are independently selected from and / or, the unsaturated dibasic acid is maleic anhydride and / or fumaric acid; and / or, the saturated dibasic acid anhydride is phthalic anhydride and / or methyltetrahydrophthalic anhydride; and / or, in formula (II), R3 and R4 are independently selected from R7 is selected from H, methyl, ethyl, propyl or methoxy; and / or, in formula (III), R5 is a hydroxyl group substituted at the para position, and R6 is selected from H, methyl, ethyl, propyl or methoxy.

10. The insulating impregnating varnish according to claim 1, characterized in that: The curing agent is an acid anhydride, and further, the acid anhydride is methyltetrahydrophthalic anhydride and / or methylnadic anhydride; and / or, The second component further comprises an initiator and a accelerator, and further, the initiator comprises a peroxide initiator, and the peroxide initiator comprises dicumyl peroxide and / or 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane; Further, the accelerator includes an amine accelerator, and the amine accelerator includes 2,4,6-tris(dimethylaminomethyl)phenol; Furthermore, the mass ratio of the acid anhydride, the initiator and the accelerator is 55-65:1.5-3.5:1.5-3.5.

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