Adhesives and their preparation methods, adhesive layers, composite films, iron cores, electrical equipment and vehicles

Abstract

This application discloses an adhesive and its preparation method, adhesive layer, composite film, iron core, electrical equipment, and vehicle. The adhesive includes a specific adhesion modifier that satisfies the molecular structure of Formula I, including a long methylene flexible chain segment and reactive end groups containing epoxy groups or hydroxyl groups. This helps the adhesive maintain sufficient bond strength while significantly reducing the brittleness and internal stress of the adhesive layer, ensuring that the adhesive layer has sufficient toughness to disperse stress, thereby preventing cracking when the roll material is peeled off.

Description

[0001] This application claims priority to Chinese Patent Application No. 202511568960.2, filed on October 29, 2025, entitled "Adhesive and Preparation Method Thereof, Adhesive Layer, Composite Film, Iron Core and Motor", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of adhesives, and more particularly to an adhesive and its preparation method, adhesive layer, composite film, iron core, electrical equipment and vehicle. Background Technology

[0003] In the process of preparing composite films, it is usually necessary to integrate multiple amorphous film rolls into a first roll, then immerse the first roll in an adhesive, and after the adhesive has cured, peel off the first roll to form a second roll of composite film with the target number of layers, and then unwind the second roll for subsequent stamping processing.

[0004] In related technologies, epoxy resin is commonly used as an impregnating adhesive in the industry. This type of adhesive has high bonding strength, which helps to firmly bond the layers of the roll material together.

[0005] However, when peeling the first roll of material, the amorphous film itself is brittle and has poor ductility. Moreover, during the peeling process, the excessive adhesive force of the adhesive layer and the stress concentration at the edge of the film can easily lead to cracking of the composite film, making it impossible to obtain a continuous composite film. Summary of the Invention

[0006] This application provides an adhesive and its preparation method, an adhesive layer, a composite film, an iron core, and a motor, aiming to improve the phenomenon of cracking of the roll material during peeling caused by excessive adhesive force and stress concentration.

[0007] To achieve the above objectives, in a first aspect, embodiments of this application provide an adhesive comprising an epoxy resin, an adhesion modifier, and a curing agent; The adhesive modifier comprises a molecular structure as shown in Formula I: R1—(CH2) n —R2 formula I; in, R1 and R2 are independently selected from H, epoxy group or hydroxyl group, respectively, and R1 and R2 cannot be H at the same time; n is any integer greater than or equal to 6.

[0008] Optionally, in some embodiments of this application, the epoxy group is independently selected from at least one of glycidyl ether type epoxy groups and glycidyl ester type epoxy groups; and / or n is any integer independently selected from 6 to 20.

[0009] Optionally, in some embodiments of this application, the glycidyl ether type epoxy group includes an octyl glycidyl ether type epoxy group, a hexanediol diglycidyl ether type epoxy group, and a C... 12~14 At least one of alkyl glycidyl ether type epoxy groups and cashew phenol glycidyl ether type epoxy groups; and / or The glycidyl ester type epoxy group includes at least one of oleic acid glycidyl ester type epoxy group and adipic acid diglycidyl ester type epoxy group.

[0010] Optionally, in some embodiments of this application, the viscosity of the adhesive modifier ranges from 10 mPa·s to 500 mPa·s; Preferably, the viscosity of the adhesive modifier is in the range of 50 mPa·s to 500 mPa·s.

[0011] Optionally, in some embodiments of this application, the epoxy resin includes at least one of bisphenol epoxy resin and alicyclic epoxy resin; and / or The curing agent includes anhydride-based curing agents; Preferably, the anhydride curing agent includes at least one of methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, and methylnadic anhydride.

[0012] Optionally, in some embodiments of this application, the adhesive comprises 30 to 70 parts by weight of the epoxy resin, 30 to 50 parts by weight of the adhesion modifier, and 70 to 150 parts by weight of the curing agent.

[0013] Optionally, in some embodiments of this application, the adhesive further includes additives; The additives include at least one of reactive diluents, toughening agents, curing accelerators, and surfactants. Preferably, the toughening agent comprises at least one of rubber-modified epoxy resin, polyurethane-modified epoxy resin, and methyl methacrylate-butadiene-styrene copolymer; Preferably, the curing accelerator includes imidazole accelerators or tertiary amine accelerators.

[0014] Optionally, in some embodiments of this application, The adhesive must satisfy at least one of the following conditions: The curing shrinkage rate of the adhesive ranges from 2% to 5%. The viscosity of the adhesive ranges from 50 mPa·s to 500 mPa·s; The adhesive is an impregnation adhesive.

[0015] Secondly, embodiments of this application provide a method for preparing an adhesive, which includes the following steps: The raw materials are mixed until they are evenly mixed to obtain the adhesive. The raw materials include epoxy resin, adhesive modifier and curing agent.

[0016] Thirdly, embodiments of this application provide an adhesive layer made of the adhesive as described above.

[0017] Fourthly, embodiments of this application provide a composite film, the composite film comprising: At least two strips; An adhesive layer is disposed between the strips.

[0018] Optionally, in some embodiments of this application, the composite film is an amorphous film; and / or The thickness of the adhesive layer ranges from 0.5 μm to 2 μm; and / or The peel force of the adhesive layer ranges from 0.02 N / mm to 0.03 N / mm; and / or The adhesive layer comprises methylene and phenyl groups, wherein the ratio of the area of ​​the characteristic peak of the methylene group to the area of ​​the characteristic peak of the phenyl group ranges from 0.5 to 0.9; and / or The thickness of the composite film ranges from 0.1 mm to 0.5 mm; and / or The stiffness of the composite film ranges from 400 N / 20 cm to 5000 N / 20 cm.

[0019] Fifthly, embodiments of this application provide an iron core, the iron core comprising the composite film as described above or the adhesive layer as described above.

[0020] Sixthly, embodiments of this application provide an electrical device, the electrical device including the iron core as described above, or the composite film as described above, or the adhesive layer as described above.

[0021] In a seventh aspect, embodiments of this application provide a vehicle, the vehicle including the electrical equipment as described above, or the iron core as described above, or the composite film as described above.

[0022] This application provides an adhesive by adding a specific adhesion modifier to an epoxy resin system. The adhesion modifier satisfies the molecular structure of Formula I, including a long methylene flexible segment and reactive end groups containing epoxy groups or hydroxyl groups. This helps the adhesive maintain sufficient bond strength while significantly reducing the brittleness and internal stress of the adhesive layer, ensuring that the adhesive layer has sufficient toughness to disperse stress, thereby preventing cracking when the roll material is peeled off. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a process flow diagram of the preparation of composite films in some embodiments of this application; Figure 2 This is a diagram showing the effect of peeling off the sample of Comparative Example 1 of this application; Figure 3 This is a diagram showing the effect of peeling off the sample in Example 1 of this application. Detailed Implementation

[0025] 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 a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the protection scope of this application.

[0026] refer to Figure 1 In the process of preparing composite films, multiple amorphous film rolls are usually integrated into a first roll, which is then immersed in an adhesive. After the adhesive cures, the first roll is peeled off to form a second roll of composite film with the target number of layers. The second roll is then unwound for subsequent stamping processing.

[0027] In related technologies, epoxy systems are commonly used as impregnating adhesives. These impregnating adhesives have high bonding strength and a rigid three-dimensional cross-linked curing network, which helps to ensure a strong bond between the adhesive layer and the amorphous film after impregnation.

[0028] However, due to the high brittleness and poor ductility of amorphous films, and the excessive adhesion of the adhesive layer and stress concentration at the film edges during the peeling process, composite films are prone to cracking, making it impossible to obtain continuous composite films. This limits the application of composite films in subsequent processing (such as stamping and delamination).

[0029] In a first aspect, this application provides an adhesive comprising an epoxy resin, an adhesion modifier, and a curing agent; wherein the adhesion modifier comprises a molecular structure as shown in Formula I: R1—(CH2) n —R2 formula I; in, R1 and R2 are independently selected from H, epoxy group or hydroxyl group, and R1 and R2 cannot be H at the same time; n is any integer greater than or equal to 6.

[0030] By adopting the above-described solution, this application embodiment develops a novel adhesive that can maintain sufficient bonding strength while significantly reducing the brittleness and internal stress of the adhesive layer. This helps ensure that the adhesive layer has sufficient toughness to disperse stress, thereby preventing cracking when peeling the roll material.

[0031] It should be further explained that in this embodiment, an adhesive modifier is added to the epoxy resin. Since the adhesive modifier includes flexible segments and reactive end groups, by chemically bonding the flexible segments to the rigid three-dimensional cross-linked network structure, a balance between toughness and strength is achieved, which helps to ensure that the roll material is not prone to cracking during the peeling process.

[0032] It should be further explained that the flexible segments are long methylene segments. When n is greater than or equal to 6, it helps to ensure that the molecular chain has sufficient flexibility. During peeling, these flexible segments can absorb energy through orientation, elongation and deformation, effectively reducing stress concentration and thus avoiding brittle fracture of the roll material during peeling.

[0033] It should be further explained that R1 and R2 are independently selected from epoxy groups or hydroxyl groups. Epoxy groups or hydroxyl groups allow the adhesive modifier to react chemically with the epoxy resin and curing agent, thereby covalently bonding to the three-dimensional cross-linked curing network of the epoxy resin. This not only ensures good compatibility between the adhesive modifier and the epoxy resin and avoids phase separation, but also guarantees the bonding strength between the adhesive layer and the amorphous film.

[0034] It should be further explained that during the peeling process, the flexible segments in the adhesive layer deform first, absorbing the peeling force and reducing the direct stress on the amorphous film. At the same time, because the stress is dispersed, the local stress that the amorphous film can withstand is greatly reduced, thereby avoiding cracking of the film. Moreover, the adhesive layer maintains good adhesion properties, which helps to ensure that there is no separation between the layers after stamping.

[0035] In some embodiments of this application, the epoxy group is independently selected from glycidyl ether type epoxy group and glycidyl ester type epoxy group.

[0036] By employing the above scheme, these two epoxy groups ensure that the adhesive modifier is covalently bonded to the three-dimensional cross-linked curing network of the epoxy resin, thereby achieving an interpenetrating structure that balances toughness and strength. The epoxy groups of the glycidyl ether type epoxy group are attached to the ether bond, and due to electronic effects, they possess moderate reactivity with a controllable reaction rate, facilitating production operations. The epoxy groups of the glycidyl ester type epoxy group can be directly linked to electron-withdrawing carbonyl groups. Due to the electron-withdrawing inductive effect, their reactivity is generally higher than that of the glycidyl ether type epoxy resin, allowing them to participate in the reaction more quickly, thus ensuring effective bonding within the three-dimensional cross-linked curing network and reducing unreacted molecular residues.

[0037] In some embodiments of this application, n is independently selected from any integer between 6 and 20.

[0038] By adopting the above scheme and taking an appropriate range of values ​​for n, it is beneficial to ensure that the flexible chain segments have a moderate length and appropriate chain segment movement capability, so that the adhesive modifier can provide excellent toughening effect and internal stress relaxation capability for the entire three-dimensional cross-linked curing network, thereby ensuring that there is no interlayer cracking of the composite film during the peeling process.

[0039] It should be noted that an n value within the aforementioned range also helps ensure good compatibility between the adhesive modifier and the epoxy resin, preventing the adhesive modifier from migrating or precipitating from the three-dimensional cross-linked curing network during or after curing. Furthermore, an appropriate n value can provide sufficient cohesive strength for smooth stamping; it also ensures that the adhesive layer undergoes significant plastic deformation rather than brittle fracture during peeling, thereby dispersing stress and effectively protecting the amorphous film.

[0040] In some embodiments of this application, the glycidyl ether type epoxy group includes octyl glycidyl ether type epoxy group, hexanediol diglycidyl ether type epoxy group, and C 12~14 At least one of alkyl glycidyl ether type epoxy group and cashew phenol glycidyl ether type epoxy group.

[0041] By adopting the above scheme, the octyl glycidyl ether type epoxy group can provide excellent flexibility, hydrophobicity, and compatibility, which is beneficial to improving the plastic deformation ability of the adhesive; the hexane glycol diglycidyl ether type epoxy group has bifunctional groups, and the hexane chain is a flexible segment of moderate length, which helps to impart good flexibility and rotational freedom between crosslinking points, so that it can have high strength while toughening, thus significantly improving the toughness and impact resistance of the three-dimensional crosslinked curing network; C 12~14 Alkyl glycidyl ether type epoxy groups have longer alkyl chains, which means a stronger internal plasticizing effect. They can more effectively isolate rigid chain segments, allowing the adhesive layer to undergo greater deformation rather than brittle fracture during peeling. Cashew phenol glycidyl ether type epoxy groups have long flexible alkyl side chains, rigid benzene rings and epoxy functional groups, thus achieving unique flexibility, hydrophobicity, extremely high bio-based content and good structural strength.

[0042] In some embodiments of this application, the glycidyl ester type epoxy group includes at least one of oleic acid glycidyl ester type epoxy group and adipic acid diglycidyl ester type epoxy group.

[0043] By adopting the above scheme, the oleic acid diglycidyl ester type epoxy group contains a long C18 alkyl chain and also a cis double bond. This long chain structure has a huge free volume and excellent molecular chain mobility, which can effectively isolate the three-dimensional cross-linking curing network of epoxy resin, absorb and disperse stress, significantly reduce modulus and improve toughness. The adipic acid diglycidyl ester type epoxy group has a bifunctional group and can directly participate in the three-dimensional cross-linking curing network, which helps to maintain a high network cohesive strength while toughening, thereby avoiding cohesive failure caused by excessive toughening.

[0044] In some embodiments of this application, the viscosity of the adhesive modifier ranges from 10 mPa·s to 500 mPa·s. Further, the viscosity of the adhesive modifier ranges from 50 mPa·s to 500 mPa·s. Exemplarily, the viscosity of the adhesive modifier can be 50 mPa·s, 80 mPa·s, 100 mPa·s, 120 mPa·s, 150 mPa·s, 170 mPa·s, 200 mPa·s, 220 mPa·s, 250 mPa·s, 280 mPa·s, 300 mPa·s, 330 mPa·s, 350 mPa·s, 380 mPa·s, 400 mPa·s, 430 mPa·s, 450 mPa·s, 470 mPa·s, 500 mPa·s, or any value between two adjacent values.

[0045] By adopting the above scheme, the adhesive modifier can act as an active diluent within a low range, which helps to effectively reduce the initial viscosity of the adhesive system when mixed with epoxy resins with higher viscosity. Moreover, the lower viscosity adhesive modifier can fully wet the surface of the film and be evenly distributed in the three-dimensional cross-linked curing network, thereby achieving toughening effect and reducing internal stress.

[0046] In some embodiments of this application, the epoxy resin includes at least one of bisphenol epoxy resin and alicyclic epoxy resin. Exemplarily, the bisphenol epoxy resin may be bisphenol A glycidyl ether type epoxy resin or bisphenol F glycidyl ether type epoxy resin.

[0047] By employing the above-mentioned methods and selecting different types of epoxy resins, it is helpful to endow the adhesive with good mechanical properties, heat resistance, viscosity, or reactivity. Bisphenolic epoxy resins and alicyclic epoxy resins, as the main body and skeleton, can provide excellent adhesion, high mechanical strength, hardness, and good reactivity, thereby ensuring high bond strength of the adhesive. At the same time, bisphenolic epoxy resins and alicyclic epoxy resins can provide higher heat resistance and better weather resistance, which is beneficial to improving the reliability of the adhesive in harsh environments.

[0048] In some embodiments of this application, the curing agent includes anhydride-based curing agents.

[0049] By adopting the above scheme, anhydride curing agents can achieve extremely low curing shrinkage when curing with epoxy resin, thereby significantly reducing the peel stress on the amorphous film caused by shrinkage and avoiding interface damage and cracking of the composite film. Furthermore, the relatively slow reaction rate of anhydride curing agents with epoxy resin provides ample operating time for processes such as mixing adhesive modifiers and impregnation.

[0050] In some embodiments of this application, the anhydride curing agent includes at least one of methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, and methylnadic anhydride.

[0051] By adopting the above scheme, the viscosity of methyltetrahydrophthalic anhydride is lower, at 25... o With a viscosity of only 50 mPa·s to 80 mPa·s at C, it can be well mixed with epoxy resins and adhesive modifiers to form a low-viscosity and homogeneous adhesive, which is beneficial for impregnation and coating. Methylhexahydrophthalic anhydride, in addition to its low viscosity, also provides high heat resistance and excellent weather resistance. Methylnadic anhydride offers even higher heat resistance, low volatility, and high stability. Based on the above analysis, suitable anhydride curing agents can be selected for different application scenarios.

[0052] In some embodiments of this application, the adhesive includes 30 to 70 parts by weight of epoxy resin, 30 to 50 parts by weight of adhesion modifier, and 70 to 150 parts by weight of curing agent.

[0053] By adopting the above scheme and using the adhesive formulated according to the above formula, it is helpful to control the interlayer peel force of the formed adhesive layer at a low level; at the same time, it can also ensure that the adhesive has low viscosity and high permeability; the adhesive of this formula has a moderate curing shrinkage rate after curing, which helps to generate less internal stress, ensures the density of the adhesive layer, and plays a key role in preventing cracking during peeling.

[0054] In some embodiments of this application, the adhesive further includes 0.1 to 20 parts by weight of an additive; wherein the additive includes at least one of an active diluent, a toughening agent, a curing accelerator, and a surfactant.

[0055] By adopting the above scheme, the reactive diluent can reduce the viscosity of the epoxy resin system and improve its wettability and permeability; the toughening agent can increase the flexibility of the cured adhesive layer, so that the adhesive layer can undergo slight deformation rather than brittle fracture when peeled; the curing accelerator can precisely control the curing reaction rate and degree of curing, thereby ensuring process stability and product consistency; during the stirring and vacuum impregnation process, the addition of surfactants can prevent air bubbles from remaining in the adhesive layer, thereby ensuring the dense and uniform properties of the adhesive layer.

[0056] In some embodiments of this application, the active diluent includes, but is not limited to, at least one of butyl glycidyl ether, phenyl glycidyl ether, 1,4-butanediol diglycidyl ether, hexanediol diglycidyl ether, polypropylene glycol diglycidyl ether, and trimethylolpropane triglycidyl ether.

[0057] In some embodiments of this application, the surfactant includes, but is not limited to, at least one of BYK-9077, BYK333, DISPERBYK-180, DISPERBYK-2152, and DISPERBYK-2055.

[0058] In some embodiments of this application, the toughening agent includes at least one of rubber-modified epoxy resin, polyurethane-modified epoxy resin, and methyl methacrylate-butadiene-styrene copolymer.

[0059] By adopting the above-mentioned methods, the toughening agents such as rubber-modified epoxy resin, polyurethane-modified epoxy resin, and methyl methacrylate-butadiene-styrene copolymer can significantly improve the toughness of the adhesive layer, balance the bonding strength and toughness, and reduce the increase in viscosity while effectively toughening the adhesive layer, thereby reducing the cracking of the film caused by stress concentration during peeling.

[0060] In some embodiments of this application, the curing accelerator includes at least one of imidazole accelerators and tertiary amine accelerators. Exemplarily, imidazole accelerators include imidazole and its derivatives, and tertiary amine accelerators include 2,4,6-tris(dimethylaminomethyl)phenol, etc.

[0061] By adopting the above scheme, both imidazole and its derivatives and 2,4,6-tris(dimethylaminomethyl)phenol, two curing accelerators, can attack epoxy groups or acid anhydrides, significantly reducing the activation energy of the reaction, thereby ensuring a complete and uniform curing reaction.

[0062] In some embodiments of this application, the adhesive is an impregnation adhesive.

[0063] It should be noted that after the amorphous thin film is stacked, the gap between the layers is very small. Since the adhesive of this application embodiment has extremely low viscosity and excellent wetting ability, it can completely and quickly penetrate into the gap between the rolls of amorphous thin film to achieve filling without dead corners or air bubbles. Therefore, the adhesive of this application embodiment can be used as an impregnation adhesive.

[0064] In some embodiments of this application, the curing shrinkage rate of the adhesive ranges from 2% to 5%. Further, the curing shrinkage rate of the adhesive ranges from 2.05% to 4%. Exemplarily, the curing shrinkage rate of the adhesive can be 2.05%, 2.23%, 2.46%, 2.58%, 2.76%, 2.83%, 2.98%, 3.03%, 3.11%, 3.27%, 3.36%, 3.48%, 3.69%, 3.81%, 4%, or any value between two adjacent values.

[0065] By adopting the above scheme, the curing shrinkage rate is within the above range, which helps to minimize the internal stress in the adhesive layer, ensure that the adhesive layer has high density, and at the same time avoid cracking between the composite film layers due to stress concentration.

[0066] In some embodiments of this application, the viscosity of the adhesive ranges from 50 mPa·s to 500 mPa·s. Exemplarily, the viscosity of the adhesive can be 50 mPa·s, 70 mPa·s, 100 mPa·s, 150 mPa·s, 200 mPa·s, 250 mPa·s, 300 mPa·s, 350 mPa·s, 400 mPa·s, 450 mPa·s, 500 mPa·s, or any value between two adjacent values.

[0067] By adopting the above-mentioned method, the viscosity of the adhesive is within the above-mentioned range. With the assistance of vacuum pressure, it helps to quickly and fully penetrate into the space between the amorphous film rolls, thereby forming a complete, uniform and bubble-free adhesive layer.

[0068] Secondly, embodiments of this application provide a method for preparing an adhesive, used to prepare the adhesive as described above, the preparation method comprising the following steps: Mix the raw materials until they are evenly mixed to obtain the adhesive; The raw materials include epoxy resin, adhesive modifier and curing agent.

[0069] By adopting the above scheme, the adhesive prepared by this method has all the beneficial effects of the aforementioned adhesives, which will not be repeated here.

[0070] Thirdly, embodiments of this application provide an adhesive layer made of the adhesive as described above.

[0071] By adopting the above-described solution, the adhesive layer of the present application embodiment has all the beneficial effects of the aforementioned adhesive, which will not be repeated here.

[0072] Fourthly, embodiments of this application provide a composite film, the composite film comprising: At least two strips; As mentioned above, the adhesive layer is placed between the two strips.

[0073] By adopting the above-described scheme, the composite film includes all the beneficial effects of the aforementioned adhesive layer, which will not be repeated here.

[0074] In some embodiments of this application, the composite film is an amorphous film.

[0075] In some embodiments of this application, the thickness of the adhesive layer ranges from 0.5 μm to 2.0 μm. Exemplarily, the thickness of the adhesive layer can be 0.5 μm, 0.6 μm, 0.7 μm, 0.8 μm, 0.9 μm, 1.0 μm, 1.1 μm, 1.2 μm, 1.3 μm, 1.4 μm, 1.5 μm, 1.6 μm, 1.7 μm, 1.8 μm, 1.9 μm, 2.0 μm, or any value between two adjacent values ​​mentioned above.

[0076] In some embodiments of this application, the peel force of the adhesive layer ranges from 0.02 N / mm to 0.03 N / mm. Exemplarily, the peel force of the adhesive can be 0.021 N / mm, 0.022 N / mm, 0.023 N / mm, 0.023 N / mm, 0.024 N / mm, 0.025 N / mm, 0.026 N / mm, 0.027 N / mm, 0.028 N / mm, 0.029 N / mm, 0.03 N / mm, or any value between two adjacent values.

[0077] In some embodiments of this application, the adhesive layer comprises methylene and phenyl groups, wherein the ratio of the area of ​​the characteristic peak of the methylene group to the area of ​​the characteristic peak of the benzene ring ranges from 0.5 to 0.9. Exemplarily, the ratio of the area of ​​the characteristic peak of the methylene group to the area of ​​the characteristic peak of the benzene ring is 0.52, 0.58, 0.63, 0.67, 0.71, 0.78, 0.86, 0.9, or any value between two adjacent values ​​mentioned above.

[0078] In some embodiments of this application, the thickness of the composite film ranges from 0.1 mm to 0.5 mm. For example, the thickness of the composite film can be 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, or any value between two adjacent values.

[0079] In some embodiments of this application, the stiffness of the composite film ranges from 400 N / 20 cm to 5000 N / 20 cm. Exemplarily, the stiffness of the composite film can be 400 N / 20 cm, 470 N / 20 cm, 520 N / 20 cm, 570 N / 20 cm, 610 N / 20 cm, 650 N / 20 cm, 720 N / 20 cm, 780 N / 20 cm, 870 N / 20 cm, 920 N / 20 cm, 990 N / 20 cm, 1000 N / 20 cm, or 1020 N / 20 cm. 1100N / 20cm, 1200N / 20cm, 1300N / 20cm, 1700N / 20cm, 2400N / 20cm, 2900N / 20cm, 3100N / 20cm, 3700N / 20cm, 4200N / 20cm, 4400N / 20cm, 4700N / 20cm, 5000N / 20cm, and any value between two adjacent values ​​mentioned above.

[0080] Fifthly, embodiments of this application provide an iron core comprising the composite film as described above or the adhesive layer as described above.

[0081] By adopting the above-mentioned scheme, the iron core includes the aforementioned composite film or adhesive layer, and the iron core has all the beneficial effects of the aforementioned composite film or adhesive layer, which will not be repeated here.

[0082] Sixthly, embodiments of this application provide an electrical device comprising the aforementioned iron core, composite film, or adhesive layer.

[0083] By adopting the above-mentioned solution, the motor includes the aforementioned iron core, the aforementioned composite film, or the aforementioned adhesive layer, and the motor has all the beneficial effects of the aforementioned iron core, the aforementioned composite film, or the aforementioned adhesive layer, which will not be repeated here.

[0084] In a seventh aspect, embodiments of this application provide a vehicle that includes the electrical equipment as described above, the iron core as described above, or the composite film as described above.

[0085] By adopting the above-mentioned solution, the vehicle includes the aforementioned electrical equipment, the aforementioned iron core, or the aforementioned composite film, and the vehicle has all the beneficial effects of the aforementioned electrical equipment, the aforementioned iron core, or the aforementioned composite film, which will not be repeated here.

[0086] 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.

[0087] Example 1 An iron core is prepared by the following method: Preparation of adhesives: 30 parts by weight of epoxy resin 170, 20 parts by weight of trimethylolpropane triglycidyl ether, 50 parts by weight of 1,6-hexanediol diglycidyl ether, 120 parts by weight of methyltetrahydrophthalic anhydride, 0.55 parts by weight of 2,4,6-tris(dimethylaminomethyl)phenol DMP30, and 0.8 parts by weight of BYK333 were stirred until uniformly mixed to obtain an adhesive. The viscosity of the adhesive was 102 mPa·s, and the curing shrinkage rate was 3.05%. Preparation of composite thin films: The amorphous thin film is stacked in 5 layers and wound into a roll. The roll is then immersed in the aforementioned adhesive for vacuum impregnation, and then removed and heated to 150°C. o Curing at C temperature for 5 hours, and then peeling the roll material after cooling to form a composite film. The film can be peeled off smoothly without cracking between the layers. Preparation of iron core: The aforementioned composite film was stamped according to the iron core structure, and it could be stamped normally, with complete sheets and no separation between the sheets.

[0088] Example 2 An iron core is prepared by the following method: Preparation of adhesives: 40 parts by weight of epoxy resin 128, 30 parts by weight of epoxy resin TDE 85, 30 parts by weight of cashew phenol glycidyl ether, 95 parts by weight of methyltetrahydrophthalic anhydride, 0.5 parts by weight of 2,4,6-tris(dimethylaminomethyl)phenol DMP30, and 0.6 parts by weight of BYK333 were mixed and stirred until homogeneous to obtain an adhesive. The viscosity of the adhesive was 472 mPa·s, and the curing shrinkage rate was 2.73%. Preparation of composite thin films: The amorphous thin film is stacked in 5 layers and wound into a roll. The roll is then immersed in the aforementioned adhesive for vacuum impregnation, and then removed and heated to 150°C. o Curing at C temperature for 5 hours, and then peeling the roll material after cooling to form a composite film. The film can be peeled off smoothly without cracking between the layers. Preparation of iron core: The aforementioned composite film was stamped according to the iron core structure, and it could be stamped normally, with complete sheets and no separation between the sheets.

[0089] Example 3 Preparation of adhesives: 30 parts by weight of epoxy resin 170, 20 parts by weight of trimethylolpropane triglycidyl ether, 50 parts by weight of diglycidyl adipic acid, 120 parts by weight of methyltetrahydrophthalic anhydride, 0.55 parts by weight of 2,4,6-tris(dimethylaminomethyl)phenol DMP30, and 0.8 parts by weight of BYK333 were stirred until uniformly mixed to obtain an adhesive. The viscosity of the adhesive was 357 mPa·s, and the curing shrinkage rate was 2.94%. Preparation of composite thin films: The amorphous thin film is stacked in 5 layers and wound into a roll. The roll is then immersed in the aforementioned adhesive for vacuum impregnation, and then removed and heated to 150°C. o Curing at C temperature for 5 hours, and then peeling the roll material after cooling to form a composite film. The film can be peeled off smoothly without cracking between the layers. Preparation of iron core: The aforementioned composite film was stamped according to the iron core structure, and it could be stamped normally, with complete sheets and no separation between the sheets.

[0090] Example 4 Preparation of adhesives: 50 parts by weight of epoxy resin 170, 15 parts by weight of trimethylolpropane triglycidyl ether, 50 parts by weight of 1,6-hexanediol diglycidyl ether, 140 parts by weight of methyltetrahydrophthalic anhydride, 0.6 parts by weight of 2,4,6-tris(dimethylaminomethyl)phenol DMP30, and 0.9 parts by weight of BYK333 were stirred until uniformly mixed to obtain an adhesive. The viscosity of the adhesive was 482 mPa·s, and the curing shrinkage rate was 2.74%. Preparation of composite thin films: The amorphous thin film is stacked in 5 layers and wound into a roll. The roll is then immersed in the aforementioned adhesive for vacuum impregnation, and then removed and heated to 150°C. o Curing at C temperature for 5 hours, and then peeling the roll material after cooling to form a composite film. The film can be peeled off smoothly without cracking between the layers. Preparation of iron core: The aforementioned composite film was stamped according to the iron core structure, and it could be stamped normally, with complete sheets and no separation between the sheets.

[0091] Example 5 An iron core differs from that of Example 1 in that the adhesive formulation is different. The iron core in this example is prepared using the following method: Preparation of adhesives: 15 parts by weight of epoxy resin 170, 35 parts by weight of trimethylolpropane triglycidyl ether, 50 parts by weight of 1,6-hexanediol diglycidyl ether, 115 parts by weight of methyltetrahydrophthalic anhydride, 0.5 parts by weight of 2,4,6-tris(dimethylaminomethyl)phenol DMP30, and 0.6 parts by weight of BYK333 were stirred until uniformly mixed to obtain an adhesive. The viscosity of the adhesive was 56 mPa·s, and the curing shrinkage rate was 4.2%. Preparation of composite thin films: The amorphous thin film is stacked in 5 layers and wound into a roll. The roll is then immersed in the aforementioned adhesive for vacuum impregnation, and then removed and heated to 150°C. o After curing at C temperature for 5 hours, the roll material is peeled off after cooling to form a composite film. No cracking occurs between the layers during the peeling process.

[0092] Comparative Example 1 An iron core, differing from that of Example 1, is provided in that no adhesive modifier is added to the adhesive. The iron core of this comparative example is prepared using the following method: Preparation of adhesives: 30 parts by weight of epoxy resin 170, 20 parts by weight of trimethylolpropane triglycidyl ether, 54 parts by weight of methyltetrahydrophthalic anhydride, 0.27 parts by weight of 2,4,6-tris(dimethylaminomethyl)phenol DMP30, and 0.4 parts by weight of BYK333 were mixed and stirred until homogeneous to obtain an adhesive. The viscosity of the adhesive was 632 mPa·s, and the curing shrinkage rate was 4.86%. Preparation of composite thin films: The amorphous thin film is stacked in 5 layers and wound into a roll. The roll is then immersed in the aforementioned adhesive for vacuum impregnation, and then removed and heated to 150°C. o After curing at C temperature for 5 hours, the roll material was peeled off to form a composite film after cooling. During the peeling process, cracks appeared between the layers. Comparative Example 2 One type of iron core differs from that of Example 2 in that the adhesive contains a different bonding modifier. The iron core of this comparative example was prepared using the following method: Preparation of adhesives: 40 parts by weight of epoxy resin 128, 30 parts by weight of epoxy resin TDE 85, 30 parts by weight of polypropylene glycol diglycidyl ether, 95 parts by weight of methyltetrahydrophthalic anhydride, 0.5 parts by weight of 2,4,6-tris(dimethylaminomethyl)phenol DMP30, and 0.6 parts by weight of BYK333 were stirred until uniformly mixed to obtain an adhesive. The viscosity of the adhesive was 421 mPa·s, and the curing shrinkage rate was 2.98%. Preparation of composite thin films: The amorphous thin film is stacked in 5 layers and wound into a roll. The roll is then immersed in the aforementioned adhesive for vacuum impregnation, and then removed and heated to 150°C. o After curing at C temperature for 5 hours, the roll material is peeled off to form a composite film after cooling. During the peeling process, cracks appear between the layers.

[0093] Comparative Example 3 One type of iron core differs from that of Example 2 in that the adhesive contains a different bonding modifier. The iron core of this comparative example was prepared using the following method: Preparation of adhesives: 40 parts by weight of epoxy resin 128, 30 parts by weight of epoxy resin TDE 85, 30 parts by weight of 1,4-butanediol diglycidyl ether, 120 parts by weight of methyltetrahydrophthalic anhydride, 0.55 parts by weight of 2,4,6-tris(dimethylaminomethyl)phenol DMP30, and 0.8 parts by weight of BYK333 were stirred until uniformly mixed to obtain an adhesive. The viscosity of the adhesive was 368 mPa·s, and the curing shrinkage rate was 3.8%. Preparation of composite thin films: The amorphous thin film is stacked in 5 layers and wound into a roll. The roll is then immersed in the aforementioned adhesive for vacuum impregnation, and then removed and heated to 150°C. o After curing at C temperature for 5 hours, the roll material is peeled off to form a composite film after cooling. During the peeling process, cracks appear between the layers.

[0094] Performance testing: (1) Viscosity: Take 200g of adhesive in a 250mL glass beaker, and then test it with the #2 rotor of the BROOKFIELD DV2T rotational viscometer at 100rpm. Read the data after 1 minute. (2) Curing shrinkage rate: The density of the adhesive before curing was measured using a liquid density meter and recorded as ρ. 液 The density of the cured adhesive layer was measured using a solid density meter and recorded as ρ. 固 The formula for calculating the curing shrinkage rate is (ρ 固 -ρ 液) / ρ 液 ; (3) Adhesive layer thickness: After the composite film fractures, the thickness of the adhesive layer at the fracture surface is observed and measured using a metallographic microscope. (4) Peeling force: The peel strength between the layers was tested according to the standard GB / T 2792-2014; (5) The ratio of the characteristic peak area of ​​the methylene group to the characteristic peak area of ​​the benzene ring: According to page 118 of "Introduction to Infrared Spectroscopy" compiled by Zhong Haiqing and published by Chemical Industry Press, "—(CH2)" n —(n>4) CH skeletal vibration at 750-720 cm⁻¹ -1 The C=C stretching vibration of the benzene ring, as described on page 120, is between 1600 and 1500 cm⁻¹. -1 ; The adhesive layer of the composite film was taken as a sample and tested using a Fourier transform infrared spectroscopy (FTIR) instrument with attenuated total reflectance (ATR) method. Readings were taken at 1510 cm⁻¹. -1 The peak area A of the characteristic peak near (phenyl) 苯环 and 720cm -1 The peak area A of the characteristic peak near (methylene) C-H Then according to A C-H / A 苯环 Perform calculations; (6) Stiffness: The composite film is cut into samples with a length of 20cm and a width of 1cm. The samples are then pressed down in a universal testing machine at a moving speed of 10mm / min. The maximum force required to press down the sample is the stiffness.

[0095] The test results are shown in Table 1: Table 1

[0096] Compared with Examples 1-5 and Comparative Examples 1-3, the adhesives of Examples 1-5 include an adhesive modifier that satisfies the molecular structure of Formula I, while no adhesive modifier was added in Comparative Example 1, and the adhesive modifiers in Comparative Examples 2-3 did not satisfy the molecular structure of Formula I. As can be seen from Table 1, the adhesive modifier satisfies the molecular structure of Formula I, which helps the adhesive to maintain sufficient bond strength and significantly reduce the brittleness and internal stress of the adhesive layer, so that the adhesive layer has sufficient toughness to disperse stress during peeling, thereby preventing cracking when peeling the roll material.

[0097] Figure 2 This is a diagram showing the peeling and cracking effect of the sample in Comparative Example 1. Figure 2It can be seen that cracks appeared between the layers of the sample in Comparative Example 1 during the peeling process.

[0098] Figure 3 This is an image showing the effect of peeling off the sample from Example 1. Figure 3 It can be seen that no cracking occurred when the sample of Example 1 was peeled off.

[0099] The adhesives, their preparation methods, adhesive layers, composite films, iron cores, electrical equipment, and vehicles provided in the embodiments of this application have been described in detail above. 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 includes epoxy resin, adhesion modifier and curing agent; The adhesive modifier comprises a molecular structure as shown in Formula I: R1—(CH2) n —R2 formula I; in, R1 and R2 are independently selected from H, epoxy group or hydroxyl group, and R1 and R2 cannot be H at the same time; n is any integer greater than or equal to 6.

2. The adhesive according to claim 1, characterized in that, The epoxy group is independently selected from at least one of glycidyl ether type epoxy group and glycidyl ester type epoxy group; and / or n is any integer independently selected from 6 to 20.

3. The adhesive according to claim 2, characterized in that, The glycidyl ether type epoxy group includes octyl glycidyl ether type epoxy group, hexanediol diglycidyl ether type epoxy group, C 12~14 At least one of alkyl glycidyl ether type epoxy groups and cashew phenol glycidyl ether type epoxy groups; and / or The glycidyl ester type epoxy group includes at least one of oleic acid glycidyl ester type epoxy group and adipic acid diglycidyl ester type epoxy group.

4. The adhesive according to any one of claims 1 to 3, characterized in that, The viscosity of the adhesive modifier ranges from 10 mPa·s to 500 mPa·s; Preferably, the viscosity of the adhesive modifier is in the range of 50 mPa·s to 500 mPa·s.

5. The adhesive according to claim 1, characterized in that, The epoxy resin includes at least one of bisphenol epoxy resin and alicyclic epoxy resin; and / or The curing agent includes anhydride-based curing agents; Preferably, the anhydride curing agent includes at least one of methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, and methylnadic anhydride.

6. The adhesive according to claim 1, characterized in that, The adhesive comprises 30 to 70 parts by weight of the epoxy resin, 30 to 50 parts by weight of the adhesion modifier, and 70 to 150 parts by weight of the curing agent.

7. The adhesive according to claim 1, characterized in that, The adhesive also includes additives; The additives include at least one of reactive diluents, toughening agents, curing accelerators, and surfactants. Preferably, the toughening agent comprises at least one of rubber-modified epoxy resin, polyurethane-modified epoxy resin, and methyl methacrylate-butadiene-styrene copolymer; Preferably, the curing accelerator includes imidazole accelerators or tertiary amine accelerators.

8. The adhesive according to claim 1, characterized in that, The adhesive must satisfy at least one of the following conditions: The curing shrinkage rate of the adhesive ranges from 2% to 5%. The viscosity of the adhesive ranges from 50 mPa·s to 500 mPa·s; The adhesive is an impregnation adhesive.

9. A method for preparing an adhesive, characterized in that, The method for preparing the adhesive as described in any one of claims 1 to 8 comprises the following steps: The raw materials are mixed until they are evenly mixed to obtain the adhesive. The raw materials include epoxy resin, adhesive modifier and curing agent.

10. An adhesive layer, characterized in that, The adhesive layer is made of the adhesive as described in any one of claims 1 to 8.

11. A composite film, characterized in that, The composite film includes: At least two strips; and The adhesive layer as described in claim 10 is disposed between the strips.

12. The composite film according to claim 11, characterized in that, The composite film is an amorphous film; and / or The thickness of the adhesive layer ranges from 0.5 μm to 2 μm; and / or The peel force of the adhesive layer ranges from 0.02 N / mm to 0.03 N / mm; and / or The adhesive layer comprises methylene and phenyl groups, wherein the ratio of the area of ​​the characteristic peak of the methylene group to the area of ​​the characteristic peak of the phenyl group ranges from 0.5 to 0.9; and / or The thickness of the composite film ranges from 0.1 mm to 0.5 mm; and / or The stiffness of the composite film ranges from 400 N / 20 cm to 5000 N / 20 cm.

13. A core, characterized in that, The iron core includes the composite film as described in claim 11 or 12 or the adhesive layer as described in claim 10.

14. An electrical appliance, characterized in that, The electrical equipment includes the iron core as described in claim 13 or the composite film as described in claim 11 or 12.

15. A vehicle, characterized in that, The vehicle includes the electrical equipment as described in claim 14 or the iron core as described in claim 13.

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