A kind of adhesive and preparation method, crosslinked polymer, composite insulating paper, oil-cooled motor

Abstract

This application relates to an adhesive and its preparation method, a crosslinked polymer, composite insulating paper, and an oil-cooled motor. The adhesive comprises the following raw materials: acrylic resin, epoxy resin, and a curing agent. The mass ratio of the acrylic resin, epoxy resin, and curing agent is (35-63):(1-5):(6-15), and the glass transition temperature (Tg) of the acrylic resin is -30℃ to -10℃. By controlling the ratio of acrylic resin and epoxy resin with a glass transition temperature (Tg) of -30℃ to -10℃ in the adhesive, this application can ensure that the glass transition temperature (Tg) of the crosslinked polymer obtained after curing the adhesive is between 0℃ and 20℃. Consequently, when this adhesive is applied to multilayer composite insulating paper, the glass transition temperature (Tg) of the multilayer composite insulating paper is between 0℃ and 20℃, thereby adjusting the stiffness of the composite insulating paper to a suitable range.

Description

Technical Field

[0001] This application relates to the field of insulating paper technology, and more particularly to an adhesive and its preparation method, cross-linked polymers, composite insulating paper, and oil-cooled motors. Background Technology

[0002] Traditional new energy vehicles use water-cooled motors, which typically employ NHN insulating paper (where N stands for NOMEX paper and H stands for polyimide film) and polyurethane adhesive. This NHN insulating paper is economical, has excellent heat resistance, and an insulation heat resistance rating of ≥180℃.

[0003] However, with the development of new energy vehicles, water-cooled motors are gradually being replaced by oil-cooled motors. The polyurethane adhesive in NHN insulation paper has poor oil resistance and easily swells or even disperses in oil, leading to delamination of the insulation paper. Existing adhesives such as epoxy resins have better oil resistance, but they often result in high stiffness after use. In particular, a thicker adhesive layer is needed to protect the intermediate resin film layer, further increasing stiffness. Both excessive and insufficient stiffness can affect installation and hinder performance in practical applications. Summary of the Invention

[0004] In view of this, this application provides an adhesive and its preparation method, a crosslinked polymer, a composite insulating paper, and an oil-cooled motor, aiming to adjust the stiffness value of existing insulating paper to a suitable range (transverse stiffness of 60N to 90N, and longitudinal stiffness of 40N to 65N).

[0005] To achieve the above objectives, according to a first aspect of this application, an adhesive is provided, comprising the following raw materials: acrylic resin, epoxy resin, and curing agent, wherein the mass ratio of the acrylic resin, the epoxy resin, and the curing agent is (35-63):(1-5):(6-15), and the glass transition temperature of the acrylic resin is -30°C to -10°C.

[0006] Optionally, the adhesive further includes an epoxy reactive diluent, wherein the mass ratio of the acrylic resin, the epoxy resin, the curing agent, and the epoxy reactive diluent is (35–63):(1–5):(6–15):(1–9); and / or

[0007] The adhesive further includes an accelerator, wherein the mass ratio of the acrylic resin, the epoxy resin, the curing agent, and the accelerator is (35–63):(1–5):(6–15):(0.1–0.5); and / or

[0008] The adhesive further includes a solvent, and the mass ratio of the acrylic resin, the epoxy resin, the curing agent and the solvent is (35-63):(1-5):(6-15):(32-55).

[0009] Optionally, the adhesive may further include the following raw materials: epoxy reactive diluent, curing agent, accelerator and solvent.

[0010] Optionally, the mass ratio of the acrylic resin, the epoxy resin, the epoxy reactive diluent, the curing agent, the accelerator, and the solvent is (42-54):(3-5):(5-6):(9-12):(0.25-0.5):(35.75-41.75).

[0011] Optionally, the acrylic resin includes one or more of acrylate polymers and polyethyl acrylate polymers.

[0012] Optionally, the epoxy resin includes one or more of bisphenol A type epoxy resin, bisphenol F type epoxy resin, phenolic type epoxy resin, phenolic type epoxy resin, and biphenyl type epoxy resin; and / or

[0013] The epoxy reactive diluent includes one or more of C8-C22 glycidyl ethers and C8-C22 glycidyl esters; and / or

[0014] The curing agent includes one or more of the following: tung oil anhydride, dodecenic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, and methylhexahydrophthalic anhydride; and / or

[0015] The accelerator includes one or more of tertiary amine accelerators, imidazole curing agents, and dicyandiamide accelerators; and / or

[0016] The solvent includes one or more of xylene, methyl isobutyl ketone, ethylene glycol butyl ether, butyl acetate, cyclohexanone, and ethyl acetate.

[0017] According to a second aspect of this application, a method for preparing an adhesive is provided, comprising the following steps:

[0018] An epoxy resin and an acrylic resin are provided and first mixed to obtain component A, wherein the glass transition temperature of the acrylic resin is -30°C to -10°C.

[0019] Provide a curing agent to obtain component B;

[0020] After the A component and the B component are mixed for the second time, an adhesive is obtained, wherein the mass ratio of the acrylic resin, the epoxy resin and the curing agent is (35-63):(1-5):(6-15).

[0021] Optionally, component A further includes an epoxy reactive diluent, and the first mixing comprises: mixing and stirring the epoxy resin and the epoxy reactive diluent for 30-60 minutes, then adding the acrylic resin and continuing to mix and stir for another 30-60 minutes; and / or

[0022] Component B further includes a solvent for dissolving the curing agent; and / or

[0023] Component B further includes an accelerator, which is added by means of dropwise addition; and / or

[0024] The crosslinking reaction temperature of the adhesive is 40–80°C, and the crosslinking reaction time of the adhesive is 4–8 hours; and / or

[0025] The second mixing time is 15–30 min; and / or

[0026] The second mixing process also includes vacuum degassing for 4-6 minutes or static degassing for 25-35 minutes.

[0027] According to a third aspect of this application, a crosslinked polymer is also provided, which is obtained by curing the above-described adhesive or the adhesive obtained by the above-described preparation method.

[0028] Optionally, the glass transition temperature of the crosslinked polymer is 0°C to 20°C.

[0029] According to a fourth aspect of this application, a composite insulating paper is also provided, the composite insulating paper comprising a first fiber paper, a first adhesive layer, a resin film, a second adhesive layer, and a second fiber paper stacked together;

[0030] The first adhesive layer and / or the second adhesive layer are prepared by the above-described adhesive, the above-described crosslinked polymer, or the above-described preparation method.

[0031] Optionally, the composite insulating paper further includes a first fiber paper, a resin film, and a second fiber paper stacked together, with the adhesive disposed between the first fiber paper and the resin film, and between the second fiber paper and the resin film.

[0032] Optionally, the glass transition temperature of the composite insulating paper is 0℃~20℃; and / or

[0033] The transverse stiffness of the composite insulating paper ranges from 60N to 90N; and / or

[0034] The longitudinal stiffness of the composite insulating paper ranges from 40N to 65N.

[0035] Optionally, the first fiber paper comprises one or more of polyaramid fiber paper, polyester fiber paper, polysulfonyl fiber paper, and inorganic fiber paper; and / or

[0036] The second fiber paper includes one or more of polyaramid fiber paper, polysulfonamide fiber paper, and inorganic fiber paper; and / or

[0037] The resin film is a polyester film, a polyimide film, a polyethylene terephthalate film, a polyethylene naphthalate film, or a polyphenylene sulfide film.

[0038] According to a fifth aspect of this application, an oil-cooled motor is also provided, comprising the composite insulating paper described above or the composite insulating paper prepared by the above-described preparation method.

[0039] In this application, by controlling the ratio of acrylic resin and epoxy resin with glass transition temperatures (Tg) of -30℃ to -10℃ in the adhesive, the glass transition temperature (Tg) of the cross-linked polymer obtained after the adhesive has hardened can be between 0℃ and 20℃. Consequently, when this adhesive is applied to multilayer composite insulating paper, the glass transition temperature (Tg) of the multilayer composite insulating paper is between 0℃ and 20℃, thereby adjusting the stiffness of the composite insulating paper to a suitable range (transverse stiffness of 60N to 90N and longitudinal stiffness of 40N to 65N).

[0040] Other features and advantages of this application will be described in detail in the following detailed description section. Attached Figure Description

[0041] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0042] Figure 1 This is a bubble layering diagram of the composite insulating paper provided in Embodiment 10 of the present invention. Detailed Implementation

[0043] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application. Furthermore, it should be understood that the specific embodiments described herein are only for illustration and explanation of this application and are not intended to limit this application.

[0044] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the specification of this invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0045] In this application, unless otherwise stated, directional terms such as "upper" and "lower" generally refer to the upper and lower positions of the device in its actual use or operating state, specifically the drawing directions in the accompanying drawings; while "inner" and "outer" refer to the outline of the device. Furthermore, in the description of this application, the term "comprising" means "including but not limited to". The terms first, second, third, etc., are used merely as illustrative purposes and do not impose numerical requirements or establish a numerical order.

[0046] In this application, "and / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. A and B can be singular or plural.

[0047] In this application, "at least one" means one or more, and "more than one" means two or more. "One or more", "at least one of the following", or similar expressions refer to any combination of these items, including any combination of single or multiple items. For example, "at least one of a, b, or c", or "at least one of a, b, and c", can both mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be single or multiple.

[0048] Various embodiments of this application may exist in the form of a range; it should be understood that the description in the form of a range is merely for convenience and brevity and should not be construed as a hard limitation on the scope of this application; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single numerical values ​​within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single numbers within the range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. Furthermore, whenever a numerical range is referred to herein, it means including any referenced number (fraction or integer) within the referred range.

[0049] The technical solution of this application is as follows:

[0050] In a first aspect, embodiments of this application provide an adhesive comprising the following raw materials: acrylic resin, epoxy resin, and curing agent, wherein the mass ratio of the acrylic resin, the epoxy resin, and the curing agent is (35-63):(1-5):(6-15), and the glass transition temperature of the acrylic resin is -30°C to -10°C.

[0051] In this application, by controlling the ratio of acrylic resin and epoxy resin in the adhesive, with glass transition temperatures (Tg) ranging from -30°C to -10°C, the glass transition temperature (Tg) of the cross-linked polymer obtained after the adhesive hardens can be set between 0°C and 20°C. Consequently, when this adhesive is applied to multilayer composite insulating paper, the glass transition temperature (Tg) of the multilayer composite insulating paper is set between 0°C and 20°C, thus adjusting the stiffness of the composite insulating paper to a suitable range (transverse stiffness of 60N to 90N, and longitudinal stiffness of 40N to 65N). Simultaneously, when this adhesive is applied to multilayer composite insulating paper, the epoxy resin exhibits good oil resistance, preventing swelling and peeling during oil immersion. The acrylic resin enhances the toughness of the adhesive and delays embrittlement during long-term oil immersion, thereby extending the service life of the composite paper. The curing agent can undergo a cross-linking reaction with acrylic resin and epoxy resin. By controlling the mass ratio of acrylic resin, epoxy resin and curing agent, the degree of cross-linking of acrylic resin and epoxy resin can be maintained between 0.8 and 1.2, thereby effectively improving the heat resistance and oil resistance of the adhesive.

[0052] It should be noted that the acrylic resin in this application has tackiness, thereby improving the initial tack of the adhesive. Since acrylic resins typically contain solvents, the acrylic resin in this application retains its tackiness even after the solvent is removed.

[0053] In some embodiments, the glass transition temperature of the acrylic resin is -25°C to -15°C.

[0054] In some embodiments, the glass transition temperature of the acrylic resin is -21°C to -18°C.

[0055] In some embodiments, the adhesive further includes an epoxy reactive diluent, wherein the mass ratio of the acrylic resin, the epoxy resin, the curing agent, and the epoxy reactive diluent is (35–63):(1–5):(6–15):(1–9). Thus, the epoxy reactive diluent can adjust the viscosity of the adhesive and improve the toughness of the crosslinked polymer, thereby adjusting the stiffness of the composite insulating paper to a suitable range (transverse stiffness of 60N–90N, longitudinal stiffness of 40N–65N).

[0056] In some embodiments, the mass ratio of the acrylic resin, the epoxy resin, the curing agent, and the accelerator is (35–63):(1–5):(6–15):(0.1–0.5). In this way, the accelerator can lower the temperature of the crosslinking reaction and increase the rate of the crosslinking reaction.

[0057] In some embodiments, the adhesive further includes a solvent, wherein the mass ratio of the acrylic resin, the epoxy resin, the curing agent, and the solvent is (35–63):(1–5):(6–15):(32–55). Thus, the solvent can adjust the viscosity of the adhesive to make it more suitable for production line manufacturing.

[0058] In some embodiments, the adhesive further includes the following raw materials: epoxy reactive diluent, curing agent, accelerator and solvent.

[0059] In some embodiments, the mass ratio of the acrylic resin, the epoxy resin, the epoxy reactive diluent, the curing agent, the accelerator, and the solvent is (42-54):(3-5):(5-6):(9-12):(0.25-0.5):(35.75-41.75).

[0060] In some embodiments, the acrylic resin includes one or more of acrylate polymers and polyethyl acrylates.

[0061] In some embodiments, the epoxy reactive diluent includes one or more of C8-C22 glycidyl ethers and C8-C22 glycidyl esters. This type of epoxy reactive diluent significantly improves the flexibility of epoxy resins. C8-C22 glycidyl ethers refer to glycidyl ethers containing 8-22 carbon atoms, such as 1,4-butanediol diglycidyl ether, glycerol triglycidyl ether, ethylene glycol diglycidyl ether, etc. C8-C22 glycidyl esters refer to glycidyl esters containing 8-22 carbon atoms, such as diglycidyl phthalate, hexahydrophthalic acid diglycidyl ester, diglycidyl adipate, etc.

[0062] In this application, both epoxy reactive diluent and acrylic resin can improve the toughness of the adhesive, allowing for free adjustment of the stiffness of the composite insulating paper. Furthermore, during long-term oil immersion, they can delay the embrittlement of the adhesive and extend the service life of the composite insulating paper.

[0063] In some embodiments, the epoxy resin includes one or more of bisphenol A type epoxy resin, bisphenol F type epoxy resin, phenolic type epoxy resin, phenolic type epoxy resin, and biphenyl type epoxy resin.

[0064] In some embodiments, the curing agent includes one or more of tung oil anhydride, dodecenic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, and methylhexahydrophthalic anhydride. Thus, this curing agent has good oil resistance and can improve the oil resistance of the adhesive.

[0065] In this application, epoxy resin and acrylate resin are compounded and cured with acid anhydride. The resulting adhesive has a high degree of cross-linking, large steric hindrance of molecular chains, and good oil resistance. The adhesive wets well with the substrate and has strong cohesion, thereby improving the bonding effectiveness of the insulating paper.

[0066] In some embodiments, the accelerator includes one or more of tertiary amine accelerators, imidazole curing agents, and dicyandiamide accelerators. Such accelerators have a significant promoting effect on high-temperature curing epoxy-anhydride systems and can also improve the adhesive strength.

[0067] In some embodiments, the accelerator is a tertiary amine accelerator.

[0068] In some embodiments, the promoter is 2,4,6-tris(dimethylaminomethyl)phenol.

[0069] In some embodiments, the solvent includes one or more of xylene, methyl isobutyl ketone, ethylene glycol butyl ether, butyl acetate, cyclohexanone, and ethyl acetate. Such solvents are good solvents for resins and are easily volatile, making them suitable for rapid removal on the production line.

[0070] In some embodiments, the solvent is one or both of xylene and butyl acetate.

[0071] In some embodiments, the solvent is ethyl acetate.

[0072] According to a third aspect of this disclosure, embodiments of this application provide a method for preparing an adhesive, comprising the following steps:

[0073] S11. Provide epoxy resin and acrylic resin, mix them first to obtain component A, wherein the glass transition temperature of the acrylic resin is -30℃ to -10℃;

[0074] S12. Provide a curing agent and a solvent, dissolve the curing agent in the solvent to obtain component B;

[0075] S13. After mixing the A component and the B component for the second time, an adhesive is obtained, wherein the mass ratio of the acrylic resin, the epoxy resin and the curing agent is (35-63):(1-5):(6-15).

[0076] In this application, components A and B react slowly, so they need to be prepared separately and then mixed before use.

[0077] In step S1,

[0078] In some embodiments, component A further includes an epoxy reactive diluent, and the first mixing includes: mixing and stirring the epoxy resin and the epoxy reactive diluent for 30 to 60 minutes, then adding the acrylic resin and continuing to mix and stir for another 30 to 60 minutes.

[0079] In this application, the epoxy resin has a high viscosity. Mixing it with an epoxy reactive diluent first can reduce its viscosity and facilitate better and more uniform mixing.

[0080] In step S2,

[0081] In some embodiments, component B further includes an accelerator, which is added dropwise. This prevents explosive polymerization caused by the large amount of heat generated during the mixing of the curing agent and the accelerator.

[0082] In some embodiments, the crosslinking reaction temperature of the adhesive is 40–80°C, for example, 45°C, 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, etc., and the crosslinking reaction time of the adhesive is 4–8 hours, for example, 4.5 hours, 5 hours, 5.5 hours, 6 hours, 6.5 hours, 7 hours, 7.5 hours. This allows for the accelerated release of gases generated by the reaction of the curing agent and the accelerator, thereby facilitating packaging and transportation.

[0083] In step S3,

[0084] In some embodiments, the second mixing time is 15 to 30 minutes, for example, 18 minutes, 20 minutes, 22 minutes, 25 minutes, 28 minutes, etc.

[0085] In some embodiments, the second mixing process further includes vacuum degassing for 4–6 minutes or static degassing for 25–35 minutes. This eliminates air bubbles introduced during the mixing process, thereby facilitating the production and coating of the adhesive.

[0086] This application provides a crosslinked polymer prepared from the above-described adhesive.

[0087] When the crosslinked polymer of this application is applied to multilayer composite insulating paper, the glass transition temperature (Tg) of the multilayer composite insulating paper is between 0°C and 20°C, thereby adjusting the stiffness of the composite insulating paper to a suitable range (transverse stiffness of 60N to 90N and longitudinal stiffness of 40N to 65N).

[0088] In some embodiments, the glass transition temperature of the crosslinked polymer is 0°C to 20°C.

[0089] The materials for epoxy resin, epoxy reactive diluent, acrylic resin, curing agent, accelerator and solvent are as described above.

[0090] This application embodiment also provides a composite insulating paper, which includes a first fiber paper, a first adhesive layer, a resin film, a second adhesive layer, and a second fiber paper stacked together;

[0091] The first adhesive layer and / or the second adhesive layer are obtained by curing the above-mentioned adhesive.

[0092] In this application, by using the above-mentioned adhesive for bonding, the glass transition temperature of the composite insulating paper can be made to be 0℃~20℃, thereby adjusting the stiffness of the composite insulating paper to a suitable range, with the transverse stiffness range being 60N~90N and the longitudinal stiffness range being 40N~65N.

[0093] In some embodiments, the composite insulating paper further includes a first fiber paper, a resin film, and a second fiber paper stacked together, with the adhesive disposed between the first fiber paper and the resin film, and between the second fiber paper and the resin film.

[0094] In this application, the fiber paper provides good high temperature resistance and oil resistance, the adhesive has good oil resistance and can effectively protect the resin film from oil erosion, and the resin film provides good mechanical and electrical properties.

[0095] In some embodiments, the first fiber paper comprises one or more of polyaramid fiber paper, polyester fiber paper, polysulfone amide fiber paper, and inorganic fiber paper. Thus, this type of fiber paper exhibits good high-temperature resistance and oil resistance.

[0096] In some embodiments, the second fiber paper comprises one or more of polyaramid fiber paper, polysulfonamide fiber paper, and inorganic fiber paper. Thus, this type of fiber paper exhibits good high-temperature resistance and oil resistance.

[0097] In some embodiments, the resin film is a polyester film, a polyimide film, a polyethylene terephthalate film, a polyethylene naphthalate film, or a polyphenylene sulfide film. Thus, such a resin film can provide good mechanical and electrical properties.

[0098] In some embodiments, the resin film is a polyethylene naphthalate film or a polyphenylene sulfide film.

[0099] In some embodiments, the resin film is a polyethylene naphthalate film.

[0100] According to a fourth aspect of this disclosure, embodiments of this application also provide a method for preparing composite insulating paper, comprising the following steps:

[0101] A cross-linked polymer, a resin film, a first fiber paper, and a second fiber paper are provided. The cross-linked polymer is respectively disposed on one side surface of the first fiber paper and one side surface of the second fiber paper. The solvent is removed, and then it is pressed with the resin film, wound up, cured, and solidified, so that the adhesive is disposed between the resin film and the first fiber paper and between the resin film and the second fiber paper to obtain a composite insulating paper, wherein the cross-linked polymer is provided.

[0102] In some embodiments, the solvent removal method is baking, with the baking temperature set in a gradient between 90 and 120°C, for example, drying in a seven-section oven at temperatures of 90°C, 100°C, 110°C, 120°C, 110°C, 100°C, and 90°C, respectively, for a baking time of 2-4 minutes. This allows for better solvent removal in a shorter time, improving the initial tack of the adhesive and facilitating bonding.

[0103] In some embodiments, the pressing pressure is 50 to 70 N.

[0104] This application also provides an oil-cooled motor, which includes the aforementioned composite insulating paper.

[0105] The present application will be specifically described below through specific embodiments. These embodiments are only some embodiments of the present application and are not intended to limit the present application. Unless otherwise specified, the raw materials used in the following embodiments are all commercially available products.

[0106] Example 1

[0107] A method for preparing an adhesive includes the following steps:

[0108] (1) Add 5 parts of 1,4-butanediol diglycidyl ether to 5 parts by weight of bisphenol A type epoxy resin, mix and stir for 30 min, then add 80 parts of ethyl acrylate PJ60004-60 containing solvent (containing 40% solvent and 60% ethyl acrylate with Tg of -19℃), and stir for 60 min to obtain component A;

[0109] (2) Add 9 parts by weight of methyltetrahydrophthalic anhydride to 5.75 parts by weight of ethyl acetate, then add 0.25 parts by weight of 2,4,6-tris(dimethylaminomethyl)phenol, and stir at 60°C for 6 hours to obtain component B;

[0110] (3) Mix and stir component A and component B for 15-30 minutes, then degas under vacuum for 5 minutes to obtain adhesive.

[0111] A method for preparing composite insulating paper includes the following steps:

[0112] (1) Using a coating and laminating machine, the adhesive is coated onto the surface of the first polyaramid fiber paper (aramid 1313) and the surface of the second polyaramid fiber paper (aramid 1313), and then dried in a seven-section oven for 3 minutes. The drying temperatures of the seven sections of the oven are 90℃, 100℃, 110℃, 120℃, 110℃, 100℃ and 90℃, respectively.

[0113] (2) The dried first polyaramid fiber paper (aramid 1313) is combined with a polyethylene naphthalate film, with the adhesive located between the two, and then wound up and cured to obtain roll 1;

[0114] (3) The dried second polyaramid fiber paper (aramid 1313) is combined with roll 1, so that the adhesive on the second polyaramid fiber paper (aramid 1313) is located between the two. The roll is wound up and then cured at 100°C for 2 hours, and then cured at 150°C for 2 hours to obtain composite insulating paper.

[0115] Example 2

[0116] This embodiment is basically the same as Example 1, except that the amount of ethyl acetate used in this embodiment is 5.5 parts by weight and the amount of 2,4,6-tris(dimethylaminomethyl)phenol is 0.5 parts by weight.

[0117] Example 3

[0118] This embodiment is basically the same as Embodiment 1, except that the amount of bisphenol A epoxy resin used in this embodiment is 4 parts by weight, the amount of 1,4-butanediol diglycidyl ether used is 6 parts by weight, the amount of ethyl acrylate used is 70 parts by weight, the amount of ethyl acetate used is 7.75 parts by weight, and the amount of methyltetrahydrophthalic anhydride used is 12 parts by weight.

[0119] Example 4

[0120] This embodiment is basically the same as Embodiment 1, except that the amount of bisphenol A epoxy resin used in this embodiment is 3 parts by weight, the amount of ethyl acrylate is 90 parts by weight, and the amount of methyltetrahydrophthalic anhydride is 10 parts by weight.

[0121] Example 5

[0122] This embodiment is basically the same as Example 1, except that the ethyl acrylate PJ60004-60 in Example 1 is replaced with polyethyl acrylate PJ60018-70 (polyethyl acrylate with a solvent content of 40% and a Tg of -24℃ of 60%).

[0123] Example 6

[0124] This embodiment is basically the same as Example 1, except that the ethyl acrylate PJ60004-60 in Example 1 is replaced with acrylic resin PJ60005-50 (acrylic resin with 40% solvent content and Tg of -15℃ of 60%).

[0125] Example 7

[0126] This embodiment is basically the same as Embodiment 1, except that the bisphenol A epoxy resin in Embodiment 1 is replaced with phenolic epoxy resin.

[0127] Example 8

[0128] This embodiment is basically the same as Embodiment 1, except that the bisphenol A epoxy resin in Embodiment 1 is replaced with biphenyl epoxy resin.

[0129] Example 9

[0130] This embodiment is basically the same as Embodiment 1, except that the drying temperatures of the seven ovens in this embodiment are 100℃, 110℃, 120℃, 130℃, 120℃, 110℃, and 100℃, respectively.

[0131] Example 10

[0132] This embodiment is basically the same as that of Embodiment 1, except that the amount of 2,4,6-tris(dimethylaminomethyl)phenol used in this embodiment is 0.75 parts by weight and the amount of ethyl acetate used is 5.25 parts by weight.

[0133] Comparative Example 1

[0134] This comparative example is basically the same as Example 1, except that ethyl acrylate PJ60004-60 was not added in this comparative example.

[0135] Comparative Example 2

[0136] This comparative example is basically the same as Example 1, except that the amount of bisphenol A type epoxy resin used in this comparative example is 7 parts by weight.

[0137] Comparative Example 3

[0138] This comparative example is basically the same as Example 1, except that the ethyl acrylate PJ60004-60 in Example 1 is replaced with methyl acrylate PJ60003-60 (containing 40% solvent and 60% methyl acrylate with a Tg of -5°C).

[0139] Comparative Example 4

[0140] This comparative example is basically the same as Example 1, except that the ethyl acrylate PJ60004-60 in Example 1 is replaced with butyl acrylate PJ60085-50 (containing 40% solvent and 60% butyl acrylate with a Tg of -42°C).

[0141] The adhesives used in the examples and comparative examples were subjected to viscosity tests, pot life tests, and Tg tests. The initial tack of the uncured composite insulating paper was evaluated, and the stiffness of the composite insulating paper was tested. The test results are shown in Table 1.

[0142] Viscosity test: The test was conducted in accordance with the national standard GB / T 22314-2008.

[0143] Pot life test: The test shall be conducted in accordance with the national standard GB / T 22314-2008. The pot life is defined as the time when the viscosity test result reaches 3 times the initial viscosity value.

[0144] Tg test: Tested according to dynamic thermomechanical analysis (DMA).

[0145] Initial tack assessment: Cut the uncured composite insulating paper into 20mm*200mm strips, peel the sample at the end, and then perform a peel strength test according to GB / T 2792-2014 "Test Method for Peel Strength of Adhesive Tapes". An average peel force <4N / 20mm is poor, 4N / 20mm ≤ average peel force <8N / 20mm is medium, and an average peel force ≥8N / 20mm is good.

[0146] Stiffness test: Cut the composite insulating paper into 10mm*200mm strip samples and conduct the test according to GB / T5591.2-2017. Select a load of 5000N and a test speed of 25mm / min. Test 5 samples in each direction and take the median value as the test result.

[0147] Table 1

[0148]

[0149]

[0150] As shown in Table 1:

[0151] Compared to Example 1, Example 10 had an increased amount of accelerator, a shorter adhesive adaptation period, and decreased initial tack of the composite insulating paper. During use, bubbling and delamination occurred during the oil soaking stage (e.g., Figure 1 (As shown). Compared to Example 1, Comparative Example 1 did not add acrylic resin, resulting in a higher Tg of the adhesive, decreased initial tack of the composite insulating paper, delamination during use, and increased stiffness of the composite insulating paper. Compared to Example 1, Comparative Example 2 used more epoxy resin, resulting in a higher Tg of the adhesive, increased stiffness of the composite insulating paper, and cracking during use. Compared to Example 1, Comparative Example 3 used acrylic resin with an increased Tg, resulting in increased stiffness of the composite insulating paper. Compared to Example 1, Comparative Example 4 used acrylic resin with a decreased Tg, resulting in decreased stiffness of the composite insulating paper, paper jams during use, and poor assembly.

[0152] The above provides a detailed description of the adhesive and its preparation method, cross-linked polymer, composite insulating paper, and oil-cooled motor provided in the embodiments of this application. Specific examples have been used to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the methods and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. An adhesive, characterized in that, The adhesive comprises the following raw materials: acrylic resin, epoxy resin, curing agent, epoxy reactive diluent, accelerator, and solvent. The mass ratio of the acrylic resin, epoxy resin, curing agent, epoxy reactive diluent, accelerator, and solvent is (35~63):(1~5):(6~15):(1~9):(0.1~0.5):(32~55). The glass transition temperature of the acrylic resin is -25℃ to -15℃. The glass transition temperature of the crosslinked polymer formed after the adhesive is cured is 0℃ to 20℃. The acrylic resin includes acrylate polymers; The epoxy resin includes one or more of bisphenol A type epoxy resin, bisphenol F type epoxy resin, phenolic type epoxy resin and biphenyl type epoxy resin. The epoxy reactive diluent includes one or more of C8-C22 glycidyl ether and C8-C22 glycidyl ester; The curing agent includes one or more of tung oil anhydride, dodecenic anhydride, phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, and methylhexahydrophthalic anhydride.

2. The adhesive according to claim 1, characterized in that, The mass ratio of the acrylic resin, the epoxy resin, the epoxy reactive diluent, the curing agent, the accelerator, and the solvent is (42~54):(3~5):(5~6):(9~12):(0.25~0.5):(35.75~41.75).

3. The adhesive according to claim 2, characterized in that, The accelerator includes one or more of tertiary amine accelerators, imidazole curing agents, and dicyandiamide accelerators; and / or The solvent includes one or more of xylene, methyl isobutyl ketone, ethylene glycol butyl ether, butyl acetate, cyclohexanone, and ethyl acetate.

4. A method for preparing an adhesive as described in any one of claims 1 to 3, characterized in that, Includes the following steps: An epoxy resin and an acrylic resin are provided and first mixed to obtain component A, wherein component A further includes an epoxy reactive diluent, and the glass transition temperature of the acrylic resin is -25°C to -15°C. A curing agent is provided to obtain component B, wherein component B further includes a solvent and an accelerator; After the A component and the B component are mixed for the second time, an adhesive is obtained, wherein the mass ratio of the acrylic resin, the epoxy resin, the curing agent, the epoxy reactive diluent, the accelerator and the solvent is (35~63):(1~5):(6~15):(1~9):(0.1~0.5):(32~55).

5. The method for preparing the adhesive according to claim 4, characterized in that, The first mixing includes: mixing and stirring epoxy resin and epoxy reactive diluent for 30-60 minutes, then adding acrylic resin and continuing to mix and stir for another 30-60 minutes; and / or Dissolve the curing agent in the solvent; and / or The accelerator is added by means of dripping; and / or The crosslinking reaction temperature of the adhesive is 40~80℃, and the crosslinking reaction time of the adhesive is 4~8h; and / or The second mixing time is 15-30 minutes; and / or The second mixing process also includes vacuum degassing for 4-6 minutes or static degassing for 25-35 minutes.

6. A crosslinked polymer, characterized in that, It is prepared by hardening the adhesive according to any one of claims 1-3 or the adhesive obtained by the preparation method according to claim 4 or 5.

7. A composite insulating paper, characterized in that: The composite insulating paper includes a first fiber paper, a first adhesive layer, a resin film, a second adhesive layer, and a second fiber paper stacked together. The first adhesive layer and / or the second adhesive layer are obtained by curing the adhesive obtained by any one of claims 1 to 3 or the adhesive obtained by the preparation method of claim 4 or 5.

8. The composite insulating paper as described in claim 7, characterized in that: The glass transition temperature of the composite insulating paper is 0℃~20℃; and / or The transverse stiffness of the composite insulating paper ranges from 60N to 90N; and / or The longitudinal stiffness of the composite insulating paper ranges from 40N to 65N.

9. The composite insulating paper according to claim 7, characterized in that, The first fiber paper includes one or more of polyaramid fiber paper, polyester fiber paper, polysulfonyl fiber paper, and inorganic fiber paper; and / or The second fiber paper includes one or more of polyaramid fiber paper, polysulfonamide fiber paper, and inorganic fiber paper; and / or The resin film is a polyimide film, a polyethylene terephthalate film, a polyethylene naphthalate film, or a polyphenylene sulfide film.

10. An oil-cooled motor, characterized in that: Includes the composite insulating paper as described in any one of claims 7-9.

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