High-bonding-performance water-based system UV insulating curing adhesive, preparation method thereof, adhesive tape and application

Abstract

The invention provides a water-based system UV insulating curing adhesive with high adhesive property, a preparation method thereof, an adhesive tape and application. The water-based system UV insulating curing adhesive with high adhesive property is prepared from the following components in parts by weight: 40 to 60 parts of water-based epoxy modified acrylic emulsion, 5 to 20 parts of water-based epoxy resin, 5 to 10 parts of modified carboxymethyl cellulose, 1 to 3 parts of photoinitiator, 0.1 to 0.4 part of antioxidant and 10 to 20 parts of flame retardant. The water-based system UV insulation curing adhesive tape with high adhesive property has the characteristics of excellent adhesive force, good insulativity, high temperature resistance and environmental protection, is particularly suitable for being applied to production and assembly of a new energy automobile battery pack, and can provide reliable guarantee for the safety and performance of the battery pack.

Description

Technical Field

[0001] The present invention relates to the field of adhesive materials, and particularly to a water-based system UV insulating and curable adhesive with high bonding performance, a preparation method thereof, a tape and an application thereof. Background Art

[0002] With the improvement of global environmental awareness and the transformation of the energy structure, new energy vehicles, as representatives of clean energy, have gradually become an important development direction in the automotive industry. As the core component of new energy vehicles, the performance of the battery directly affects the power performance, driving range and safety of the whole vehicle. Therefore, the structural design, protection measures and material selection of the battery pack are particularly crucial.

[0003] In the manufacturing process of new energy vehicle battery packs, bonding technology plays a crucial role. A battery pack usually consists of multiple battery cells, and bonding technology is required to firmly connect components such as battery cells, battery management systems (BMS), heat dissipation systems and the housing to ensure the stability, safety and durability of the battery pack. Tape materials with good bonding performance can not only provide strong adhesion, but also ensure the sealing and insulation performance of the battery pack.

[0004] Currently, the development trend of bonding materials for new energy vehicle battery packs mainly focuses on high bonding performance, water-based systems and environmental friendliness. In this context, water-based system UV curable tapes, as a new type of battery pack bonding material, have gradually attracted the attention of the industry. Based on a water-based system, this material has the advantages of low volatility and less release of harmful substances, meeting the requirements of green environmental protection. At the same time, UV (ultraviolet) curing technology can cure quickly in a short time, saving production time, improving work efficiency, and forming a tough insulating layer after curing, with excellent electrical insulation performance to prevent short circuits or electrical failures of internal electrical components in the battery pack.

[0005] In addition, UV curable water-based tapes not only have excellent bonding performance, but also have good anti-aging performance and high temperature resistance, which are crucial for the stability of battery packs during long-term use. With the rapid development of the new energy vehicle market, the performance requirements for battery packs are also getting higher and higher, especially the performance in harsh environments such as high temperature and high humidity, requiring bonding materials to have higher reliability and stability.

[0006] Therefore, the research and development of water-based system UV curable tapes with high bonding performance, good insulation and environmental protection performance has become an important technical direction in the manufacturing of new energy vehicle battery packs. This new type of tape can not only improve the structural reliability of the battery pack, but also effectively enhance the safety and service life of the battery, providing technical support for the sustainable development of the new energy vehicle industry. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to provide a high-adhesion waterborne UV-insulating curing adhesive, its preparation method, tape and application in view of the deficiencies in the above-mentioned prior art. The high-adhesion waterborne UV-insulating curing adhesive is composed of various components such as polymer materials, UV-curing resins, and reinforcing fillers. On the basis of ensuring high-strength adhesion during the assembly of the battery pack, it has excellent electrical insulation performance and has the characteristics of UV curing, and can be quickly cured under ultraviolet irradiation to form a durable bonding structure.

[0008] To achieve the above object, the technical solution adopted by the present invention is: In the first aspect of the present invention, a high-adhesion waterborne UV-insulating curing adhesive is provided, which includes the following components by weight:

[0009] 40-60 parts of waterborne epoxy-modified acrylic emulsion, 5-20 parts of waterborne epoxy resin, 5-10 parts of modified carboxymethyl cellulose, 1-3 parts of photoinitiator, 0.1-0.4 parts of antioxidant, 10-20 parts of flame retardant.

[0010] Preferably, the waterborne epoxy-modified acrylic emulsion is polymerized from the following raw materials by weight: 10-22 parts of epoxy resin, 20-50 parts of n-butanol, 3-5 parts of functional monomer, 20-40 parts of soft monomer, 20-40 parts of hard monomer, 1-4 parts of initiator, 30-60 parts of deionized water.

[0011] Preferably, the epoxy resin is one or more of epoxy resin E20, E21, and E51;

[0012] The functional monomer is one or more of 1-vinyl-2-pyrrolidone, cyclopolymerizable monomer, and methacrylic acid;

[0013] The soft monomer is one or more of 2-ethylhexyl acrylate, butyl acrylate, lauryl acrylate, and methoxyethyl acrylate;

[0014] The hard monomer is one or more of 2-hydroxyethyl acrylate, 4-hydroxybutyl acrylate, and glycidyl methacrylate;

[0015] The initiator is benzoyl peroxide.

[0016] Preferably, the waterborne epoxy-modified acrylic emulsion is prepared by the following method:

[0017] S1. Add the epoxy resin to n-butanol and heat to 120 °C while stirring;

[0018] S2. Mix the soft monomer, hard monomer, functional monomer, and initiator evenly to obtain a reaction solution;

[0019] S3, adding the reaction solution dropwise to the mixture obtained in step S1, reacting at 120° C. for 2.5 hours to obtain waterborne epoxy-modified acrylic acid, cooling to 50° C., adding N,N-dimethylethanolamine to neutralize into salt, and keeping the temperature for half an hour;

[0020] S4. Add deionized water dropwise to the water-based epoxy-modified acrylic acid at a stirring speed of 3000 r / min (preferably, the mass ratio of water-based epoxy-modified acrylic acid to deionized water is 1:1) to fully disperse the mixture to obtain a water-based epoxy-modified acrylic acid emulsion.

[0021] Preferably, the modified carboxymethyl cellulose is obtained by using potassium persulfate to initiate a graft copolymerization reaction between methyl methacrylate monomer and carboxymethyl cellulose in water.

[0022] Preferably, the preparation method of the modified carboxymethyl cellulose is:

[0023] S1: Add 60 parts of carboxymethyl cellulose and 1000 parts of deionized water into a four-necked flask, heat to 80°C with nitrogen, and stir thoroughly to dissolve;

[0024] S2: After stirring for 30 minutes, add 3 parts of potassium persulfate and keep warm for 10 minutes

[0025] S3: Add 30 parts of methyl methacrylate, keep the temperature for reaction for 3 hours, then cool down to obtain modified carboxymethyl cellulose.

[0026] Preferably, the water-based epoxy resin is one or more of DIC's EXA-8420-60W, DIC's EPICLON H-502-42W, and Shuai Ke Chemical's SK2132 water-based epoxy ester resin;

[0027] The photoinitiator is photoinitiator 2959;

[0028] The flame retardant is one or more of diethyl aluminum hypophosphite or melamine cyanurate.

[0029] A second aspect of the present invention provides a method for preparing the water-based UV insulating curing adhesive with high bonding performance as described above, comprising the following steps:

[0030] In a light-proof environment, water-based epoxy-modified acrylic emulsion, water-based epoxy resin, modified carboxymethyl cellulose, photoinitiator, antioxidant and flame retardant are mixed and stirred evenly to obtain a water-based system UV insulation curing adhesive with high bonding performance.

[0031] A third aspect of the present invention provides a water-based UV insulating curing tape with high bonding performance, which is prepared by the following method:

[0032] Coat a water-based UV insulating and curable adhesive with high adhesion performance on an insulating substrate, and attach a release film to the adhesive surface after drying to obtain the water-based UV insulating and curable tape with high adhesion performance.

[0033] In the fourth aspect of the present invention, there is provided an application of the water-based UV insulating and curable tape with high adhesion performance as described above in a battery pack. The application method is as follows: Attach the water-based UV insulating and curable tape with high adhesion performance to the surface of the battery housing, and let it stand after UV curing; the energy density of UV curing is 3000 - 5000 mJ / cm 2 , and the time of UV curing is 10 s - 1 min.

[0034] The beneficial effects of the present invention are as follows:

[0035] The present invention provides a water-based UV insulating and curable adhesive with high adhesion performance, its preparation method, tape and application. After being irradiated by UVA light (wavelength 365 nm), the UV insulating and curable adhesive provided by the present invention can be quickly cured and the curing effect is uniform, without the problem of inconsistent curing degree. It has the advantages of fast curing speed, strong thermal stability, strong adaptability and easy processing. The water-based UV insulating and curable tape with high adhesion performance of the present invention has excellent adhesion, good insulation, high temperature resistance and environmental protection characteristics, and is particularly suitable for application in the production and assembly of new energy vehicle battery packs, and can provide reliable guarantee for the safety and performance of battery packs.

[0036] The UV insulating and curable adhesive provided by the present invention has the advantages of good environmental protection and low VOC (volatile organic compound) emission. No harmful solvents are required during the curing process, which reduces the emission of harmful gases and meets the requirements of green environmental protection. From the perspective of the chemical reaction mechanism, during the coating and curing process of the water-based tape, the resin in the tape is separated from the water-based solvent. After the water evaporates, the resin gradually forms a solid layer, enhancing the adhesion performance.

[0037] In some preferred embodiments, the insulating and curable tape of the present invention can reach the following indicators: Attach the insulating and curable tape to an aluminum plate, after UV curing, the shear strength > 14 MPa and the peel strength > 35 N / inch at 23°C; The insulating and curable tape of the present invention has the advantage of high adhesion performance and has good application prospects in the field of battery insulating films. Detailed Description of the Invention

[0038] The following further describes the present invention in detail with reference to embodiments, so that those skilled in the art can implement it according to the description in the specification.

[0039] It should be understood that the terms such as "having", "comprising" and "including" used herein do not exclude the presence or addition of one or more other elements or their combinations.

[0040] Unless otherwise specified, the test methods used in the following examples are all conventional methods. The materials, reagents, etc. used in the following examples can all be obtained through commercial channels unless otherwise specified. For those not indicating specific conditions in the following examples, they are carried out according to conventional conditions or the conditions recommended by the manufacturer. For reagents or instruments without indicating the manufacturer, they are all conventional products that can be obtained through commercial purchase.

[0041] The present invention provides a waterborne system UV insulating curing adhesive with high adhesion performance, comprising the following components by weight:

[0042] 40 - 60 parts of waterborne epoxy-modified acrylic emulsion, 5 - 20 parts of waterborne epoxy resin, 5 - 10 parts of modified carboxymethyl cellulose, 1 - 3 parts of photoinitiator, 0.1 - 0.4 parts of antioxidant, 10 - 20 parts of flame retardant.

[0043] In a preferred embodiment, the waterborne epoxy-modified acrylic emulsion is polymerized from the following raw materials by weight: 10 - 22 parts of epoxy resin, 20 - 50 parts of n-butanol, 3 - 5 parts of functional monomer, 20 - 40 parts of soft monomer, 20 - 40 parts of hard monomer, 1 - 4 parts of initiator, 30 - 60 parts of deionized water.

[0044] In a preferred embodiment, the epoxy resin is one or several of epoxy resin E20, E21, E51; more preferably, the epoxy resin used is epoxy resin E20. E20 is a low molecular weight epoxy resin with low volatility, which is beneficial to reducing the use of solvents, thereby reducing the emission of volatile organic compounds (VOC). This makes the waterborne epoxy-modified acrylic resin synthesized using E20 more compliant with environmental protection requirements and suitable for the development of low-VOC waterborne coatings and adhesives.

[0045] In a preferred embodiment, the functional monomer is one or several of 1-vinyl-2-pyrrolidone, cyclopolymerizable monomer, methacrylic acid; more preferably, the functional monomer used is methacrylic acid. The acrylic acid group (-COOH) in methacrylic acid can crosslink with the epoxy group in the epoxy resin. The three-dimensional network structure formed by this crosslinking reaction greatly improves the mechanical properties (such as hardness, impact resistance) and chemical resistance of the resin. The carboxyl group (-COOH) in methacrylic acid has hydrophilicity. Therefore, using methacrylic acid as the functional monomer in the waterborne system can increase the hydrophilicity of the resin and improve its dispersibility in the aqueous phase. The methyl group (-CH3) in methacrylic acid can endow the resin with certain thermal stability. The introduction of the methyl group helps to improve the heat resistance of the resin, making the final waterborne epoxy-modified acrylic resin perform more stably at high temperatures.

[0046] In a preferred embodiment, the soft monomer is one or more of 2-ethylhexyl acrylate, butyl acrylate, lauryl acrylate, and methoxyethyl acrylate; more preferably, the soft monomer used is methoxyethyl acrylate, and the methoxy group of methoxyethyl acrylate increases polarity, which can improve the compatibility of the resin with water. Since the main requirement of water-based resins is to be able to disperse in the aqueous phase and form a stable emulsion, the addition of methoxyethyl ester helps to enhance the dispersibility and stability of the resin in water. The methoxyethyl ester group, as a flexible segment, can reduce the glass transition temperature (Tg) of the resin, making the resin more stable and less prone to brittle cracking in a low temperature environment.

[0047] In a preferred embodiment, the hard monomer is one or more of hydroxyethyl acrylate, 4-hydroxybutyl acrylate, and glycidyl methacrylate; more preferably, the hard monomer used is hydroxyethyl acrylate, and the molecular structure of hydroxyethyl acrylate contains hydroxyl (-OH) and acrylic acid group (-COOH). The presence of hydroxyl group can increase the hydrophilicity of the resin and improve the dispersibility and stability of the water-based resin. The acrylic acid group has strong activity and can react with the epoxy group in the epoxy resin to produce a cross-linking reaction. Through this reaction, hydroxyethyl acrylate can participate in the cross-linking process of the resin and improve the mechanical strength and durability of the resin.

[0048] In a preferred embodiment, the initiator is benzoyl peroxide.

[0049] In a preferred embodiment, the waterborne epoxy-modified acrylic emulsion is prepared by the following method:

[0050] S1. Add epoxy resin to n-butanol and heat to 120°C while stirring;

[0051] S2, mixing the soft monomer, the hard monomer, the functional monomer and the initiator uniformly to obtain a reaction solution;

[0052] S3, adding the reaction solution dropwise to the mixture obtained in step S1, reacting at 120° C. for 2.5 hours to obtain waterborne epoxy-modified acrylic acid, cooling to 50° C., adding N,N-dimethylethanolamine to neutralize into salt, and keeping the temperature for half an hour;

[0053] S4, increasing the stirring speed to 3000 r / min, adding deionized water dropwise to the waterborne epoxy-modified acrylic acid (preferably, the mass ratio of waterborne epoxy-modified acrylic acid to deionized water is 1:1), and fully dispersing to obtain a waterborne epoxy-modified acrylic acid emulsion.

[0054] In a preferred embodiment, the modified carboxymethyl cellulose is obtained by using potassium persulfate to initiate a graft copolymerization reaction between methyl methacrylate monomer and carboxymethyl cellulose in water. More preferably, the preparation method of the modified carboxymethyl cellulose is:

[0055] S1: Add 60 parts of carboxymethyl cellulose and 1000 parts of deionized water into a four-necked flask, pass nitrogen, heat to 80 °C, and stir thoroughly to dissolve.

[0056] S2: After stirring for 30 min, add 3 parts of potassium persulfate and keep the temperature for reaction for 10 min.

[0057] S3: Add 30 parts of methyl methacrylate, keep the temperature for reaction for 3 h, and then cool down to obtain modified carboxymethyl cellulose.

[0058] In a preferred embodiment, the waterborne epoxy resin is one or more of EXA-8420-60W of DIC, EPICLON H-502-42W of DIC, and SK2132 waterborne epoxy ester resin of ShuaiKe Chemical Industry; more preferably, the waterborne epoxy resin is EXA-8420-60W of DIC.

[0059] In a preferred embodiment, the photoinitiator is photoinitiator 2959, that is, Irgacure 2959; Irgacure 2959 can be well compatible with the waterborne adhesive system. Especially in the waterborne UV-curable tape, it can keep the performance of the adhesive stable and will not cause excessive chemical reactions or dissolution problems. It can achieve low migration and good dispersion in the waterborne system, thus ensuring the long-term use stability of the tape. Irgacure 2959 has low volatility during use, which is very beneficial for improving environmental protection. It is not easy to generate harmful gases or pollutants and meets the requirements of green environmental protection.

[0060] In a preferred embodiment, the antioxidant is a liquid antioxidant formed by compounding and emulsifying technology of a high molecular hindered phenol and its thioester auxiliary antioxidant. This antioxidant has high activity, low volatility, small particle size, and is an aqueous emulsion, which greatly improves the antioxidant property of the product, improves the high-temperature resistance of the product, and improves the yellowing situation of the product during the production process.

[0061] The flame retardant is one or more of aluminum diethylphosphinate or melamine cyanurate. More preferably, the flame retardant is melamine cyanurate with a particle size of 2 - 8 μm.

[0062] The present invention also provides a preparation method of the high-adhesion waterborne system UV insulating curing glue as above, including the following steps:

[0063] Under a light-shielded environment, mix the waterborne epoxy-modified acrylic emulsion, waterborne epoxy resin, modified carboxymethyl cellulose, photoinitiator, antioxidant, and flame retardant, and stir evenly to obtain the high-adhesion waterborne system UV insulating curing glue.

[0064] The present invention also provides a waterborne UV insulating and curable tape with high adhesion performance, which is prepared by the following method:

[0065] Coat the waterborne UV insulating and curable adhesive with high adhesion performance on an insulating substrate, and after drying, attach a release film to the adhesive surface to obtain the waterborne UV insulating and curable tape with high adhesion performance.

[0066] The present invention also provides an application of the waterborne UV insulating and curable tape with high adhesion performance as described above in a battery pack. The application method is: attach the waterborne UV insulating and curable tape with high adhesion performance to the surface of the battery case, and let it stand after UV curing.

[0067] In a preferred embodiment, the energy density of UV curing is 3000 - 5000 mJ / cm 2 , and the time of UV curing is 10 s - 1 min.

[0068] The waterborne UV curable adhesive provided by the present invention participates in the free radical curing reaction during the UV curing reaction through the prepared waterborne epoxy modified acrylic emulsion, achieving a large - scale chain growth. And the epoxy groups therein participate in the cross - linking reaction during the curing process, enhancing the cured resin network structure, and improving the adhesion strength, heat resistance and chemical resistance. In addition to participating in the free radical reaction, the modified carboxymethyl cellulose can interact with the reactive groups (such as epoxy groups, hydroxyl groups, etc.) in the waterborne epoxy modified acrylic system through the carboxymethyl groups and cellulose functional groups in its structure, forming a cross - linked network, further improving the physical properties and stability after curing.

[0069] The above is the overall concept of the present invention. Hereinafter, detailed examples and comparative examples are provided on this basis to further illustrate the present invention.

[0070] The sources of the main raw materials involved in the following examples and comparative examples are as follows:

[0071] Epoxy resin E20: Sinopec Baling Petrochemical Co., Ltd.

[0072] Methacrylic acid: Shandong Quark Chemical Co., Ltd.

[0073] Methoxyethyl acrylate: Jinan Century Tongda Chemical Co., Ltd.

[0074] 2 - Hydroxyethyl acrylate: Shanghai Tongyuan Chemical Co., Ltd.

[0075] Benzoyl peroxide: Wuxi Zhanwang Chemical Reagent Co., Ltd.

[0076] Waterborne epoxy resin: EXA - 8420 - 60W of DIC

[0077] N,N-Dimethylethanolamine: Xindian Chemical Materials (Shanghai) Co., Ltd.

[0078] Carboxymethyl cellulose: Langfang Longteng New Materials Co., Ltd.

[0079] Methyl methacrylate: Shandong Mengkangda Chemical Co., Ltd.

[0080] Potassium persulfate: Shaanxi Baohua Technology Co., Ltd.

[0081] Photoinitiator-2959:Guangzhou Weber Technology Co., Ltd.

[0082] Antioxidant: PW-138 from Panhua Chemical Co., Ltd.

[0083] Flame retardant-melamine cyanurate: Jinan Jinbang Environmental Protection Technology Co., Ltd.

[0084] Example 1

[0085] A high-bonding performance water-based system UV insulation curing adhesive, the preparation method of which comprises the following steps: in a light-proof environment, by weight, 40 parts of water-based epoxy-modified acrylic emulsion, 10 parts of water-based epoxy resin, 5 parts of modified carboxymethyl cellulose, 1 part of photoinitiator, 0.2 parts of antioxidant, and 10 parts of flame retardant are stirred uniformly to obtain a high-bonding performance water-based system UV insulation curing adhesive.

[0086] In this embodiment, the raw materials for preparing the water-based epoxy-modified acrylic emulsion include, by weight: 20 parts of epoxy resin E20, 40 parts of n-butanol, 4 parts of functional monomer-methacrylic acid, 20 parts of soft monomer-methoxyethyl acrylate, 20 parts of hard monomer-hydroxyethyl acrylate, and 3 parts of initiator-benzoyl peroxide through graft polymerization.

[0087] In this embodiment, the preparation method of the water-based epoxy-modified acrylic emulsion comprises the following steps:

[0088] S1, add 20 parts of epoxy resin E20 into a four-necked flask, add 40 parts of solvent n-butanol, and heat to 120°C while stirring;

[0089] S2, fully mixing the soft monomer-methoxyethyl acrylate, the hard monomer-hydroxyethyl acrylate, the functional monomer-methacrylic acid, and the initiator-benzoyl peroxide to obtain a reaction solution;

[0090] S3, gradually dripping the reaction solution into a four-necked flask through a peristaltic pump, keeping the temperature for 2.5 hours to obtain waterborne epoxy-modified acrylic acid, cooling to 50°C, adding 40 parts of N,N-dimethylethanolamine to neutralize into salt, and keeping the temperature for half an hour;

[0091] S4. After the heat preservation reaction is completed, increase the stirring speed to 3000 r / min, and add 60 parts of deionized water dropwise to obtain a waterborne epoxy-modified acrylic emulsion by sufficient dispersion.

[0092] The viscosity (25 °C) of the waterborne epoxy-modified acrylic emulsion prepared in this example is 633 / mPa·s, and the glass transition temperature is 86.4 °C.

[0093] In this example, the raw materials for preparing the modified carboxymethyl cellulose include, by weight: 60 parts of carboxymethyl cellulose, 1000 parts of deionized water, 3 parts of potassium persulfate, and 30 parts of methyl methacrylate.

[0094] In this example, the preparation method of the modified carboxymethyl cellulose includes the following steps:

[0095] S1: Add 60 parts of carboxymethyl cellulose and 1000 parts of deionized water to a four-necked flask, and heat to 80 °C under nitrogen and stir thoroughly to dissolve;

[0096] S2: After stirring for 30 min, add 3 parts of potassium persulfate and carry out a heat preservation reaction for 10 min

[0097] S3: Add 30 parts of methyl methacrylate, carry out a heat preservation reaction for 3 h, and then cool down to obtain the modified carboxymethyl cellulose.

[0098] A waterborne system UV insulating and curing tape with high adhesion performance is prepared by the following method:

[0099] Apply the prepared waterborne system UV insulating and curing adhesive with high adhesion performance onto a transparent PET substrate layer with a thickness of 50 μm by a doctor blade, control the dry adhesive thickness to 25 ± 3 μm, bake at 120 °C for 5 min, and finally laminate a release film with a thickness of 25 μm on the adhesive surface to make a waterborne system UV insulating and curing tape with high adhesion performance.

[0100] Example 2

[0101] This example is basically the same as Example 1, except that: in this example, the preparation method of the waterborne system UV insulating and curing adhesive with high adhesion performance includes the following steps: In a light-shielded environment, by weight, 40 parts of waterborne epoxy-modified acrylic emulsion, 10 parts of waterborne epoxy resin, 7 parts of modified carboxymethyl cellulose, 1 part of photoinitiator, 0.2 part of antioxidant, and 10 parts of flame retardant are stirred evenly to obtain a waterborne system UV insulating and curing adhesive with high adhesion performance

[0102] Example 3

[0103] This example is basically the same as Example 1, except that: in this example, the preparation method of the high adhesion performance water-based system UV insulating and curing adhesive comprises the following steps: in a light-shielded environment, by weight, 40 parts of water-based epoxy-modified acrylic emulsion, 10 parts of water-based epoxy resin, 9 parts of modified carboxymethyl cellulose, 1 part of photoinitiator, 0.2 part of antioxidant, and 10 parts of flame retardant are stirred evenly to obtain this adhesive. Other structures, materials, and preparation methods are the same as those in Example 1.

[0104] Example 4

[0105] This example is basically the same as Example 1, except that: in this example, the preparation method of the high adhesion performance water-based system UV insulating and curing adhesive comprises the following steps: in a light-shielded environment, by weight, 40 parts of water-based epoxy-modified acrylic emulsion, 20 parts of water-based epoxy resin, 5 parts of modified carboxymethyl cellulose, 1 part of photoinitiator, 0.2 part of antioxidant, and 10 parts of flame retardant are stirred evenly to obtain this adhesive. Other structures, materials, and preparation methods are the same as those in Example 1.

[0106] Comparative Example 1

[0107] This example is basically the same as Example 1, except that: in this example, in the preparation raw materials of the water-based epoxy-modified acrylic emulsion, the addition amount of epoxy resin E20 is 25 parts by weight.

[0108] Comparative Example 2

[0109] This example is basically the same as Example 1, except that: in this example, in the preparation raw materials of the water-based epoxy-modified acrylic emulsion, the addition amount of the functional monomer - methacrylic acid is 2 parts by weight.

[0110] Comparative Example 3

[0111] This example is basically the same as Example 1, except that: in this example, in the preparation raw materials of the water-based epoxy-modified acrylic emulsion, the addition amount of the functional monomer - methacrylic acid is 6 parts by weight.

[0112] Comparative Example 4

[0113] This example is basically the same as Example 1, except that: in this example, in the preparation raw materials of the water-based epoxy-modified acrylic emulsion, the addition amount of the initiator - benzoyl peroxide is 5 parts by weight.

[0114] Comparative Example 5

[0115] This example is basically the same as Example 1, except that: in this example, in the preparation raw materials of the water-based epoxy-modified acrylic emulsion, the addition amount of the initiator - benzoyl peroxide is 7 parts by weight.

[0116] The following performance tests were conducted on the UV-curable insulating tapes prepared in the above Examples 1-4 and Comparative Examples 1-5:

[0117] 1. Peel strength test on 3003 aluminum plate

[0118] (1) After sampling at different positions of the tape, leave it standing in a standard environment for 24 h;

[0119] (2) Cut the tape into pieces of 25.4 mm * 300 mm, a total of 5 pieces;

[0120] (3) Remove the release layer of the tape, attach the prepared UV-curable insulating tape to the surface of the battery case, and complete the use after UV curing (irradiation with 3500 mJ / cm 2 UV light of 365 nm for 30 s) and standing (24 h).

[0121] (4) After curing, measure according to the standard of GB / T 2792-1998, and the requirement is > 35 N / inch.

[0122] 2. Shear test on 3003 aluminum plate

[0123] (1) After sampling at different positions of the tape, leave it standing in a standard environment for 24 h;

[0124] (2) Cut the tape into pieces of 25.4 mm * 12.5 mm, a total of 5 pieces;

[0125] (3) Remove the release layer of the tape, and complete the use after UV curing (irradiation with 3500 mJ / cm 2 UV light of 365 nm for 30 s) and standing (24 h).

[0126] (4) After curing, measure according to the standard of GB / T 7124-2008, and conduct the test at a speed of 5 mm / min, and the requirement is > 14 MPa;

[0127] 3. Insulation performance test:

[0128] Under the conditions of 500 VDC and 60 s, measure according to the standard of GB / T 24343-2009, and the requirement is: insulation resistance > 1 GΩ;

[0129] 4. High-voltage resistance test:

[0130] Under the conditions of 1500 VDC @ 60 s, it is not broken down, and the requirement is: leakage current < 0.2 mA.

[0131]

[0132] As can be seen from the above Examples 1 - 3, the addition amount of the modified carboxymethyl cellulose needs to be strictly controlled because its role in the UV curing reaction is closely related to its concentration. If the addition amount is too much or too little, it may affect the curing performance of the adhesive. Excessive modified carboxymethyl cellulose will significantly increase the viscosity of the adhesive, which leads to uneven penetration of light into the deep layer of the adhesive layer during the curing process, resulting in local uncured areas and a decrease in the peeling performance. The modified carboxymethyl cellulose can form hydrogen bonds with the substrate surface or the adhesive layer to increase the adhesion. Too little modified carboxymethyl cellulose may not provide sufficient adhesion force, resulting in a decrease in the peeling force.

[0133] As can be seen from the comparison between Example 1 and Example 4, the UV curing process usually involves the reaction of acrylic monomers and initiators together to generate free radicals and participate in the cross - linking reaction. If the content of the water - based epoxy resin is too high, it may compete with the acrylic groups in the reaction, reducing the cross - linking density of the acrylic groups, thus causing a decrease in the peeling force.

[0134] Compared with the examples, in Comparative Example 1, the addition amount of epoxy resin E20 was increased. When the amount of epoxy resin used increases, the peeling force will decrease. This may be because the compatibility of the excessive epoxy resin with the system becomes poor, resulting in a deterioration of the performance of the final adhesive.

[0135] Compared with the examples, in Comparative Examples 2 and 3, the addition amount of the functional monomer - methacrylic acid was adjusted. As a functional monomer, methacrylic acid contains a carboxyl group that provides a water - soluble hydrophilic group for the grafted product, which has a great influence on the stability of the finally synthesized water - based epoxy - modified acrylic acid. When the amount of carboxyl groups is small, there are a large number of precipitates at the bottom layer of the synthesized water - based epoxy - modified acrylic acid, and the adhesive will also have defects due to insufficient cross - linking degree. When the carboxyl groups introduced into the system are excessive and the cross - linking degree of the adhesive is too high, it will cause problems such as brittleness or even breakage of the tape during the final peeling force test.

[0136] Compared with the examples, in Comparative Examples 4 and 5, the amount of the initiator - benzoyl peroxide was increased. When the amount of the initiator increases, the excess free radicals will promote the self - polymerization reaction between the monomers, resulting in a decrease in the grafting rate of the monomers and affecting the bonding performance of the final tape to the substrate.

[0137] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and embodiments. It can be fully applied to various fields suitable for the present invention. For those familiar with the field, additional modifications can be easily made. Therefore, without departing from the general concept defined by the claims and the equivalent scope, the present invention is not limited to specific details.

Claims

1. A water-based UV insulating and curable adhesive with high bonding performance, characterized in that, Comprising the following components by weight parts: 40 - 60 parts of waterborne epoxy modified acrylic emulsion, 5 - 20 parts of waterborne epoxy resin, 5 - 10 parts of modified carboxymethyl cellulose, 1 - 3 parts of photoinitiator, 0.1 - 0.4 parts of antioxidant, 10 - 20 parts of flame retardant.

2. The water-based system UV insulating and curable adhesive with high adhesive performance according to claim 1, characterized in that The waterborne epoxy modified acrylic emulsion is obtained by polymerizing the following raw materials by weight parts: 10 - 22 parts of epoxy resin, 20 - 50 parts of n - butanol, 3 - 5 parts of functional monomer, 20 - 40 parts of soft monomer, 20 - 40 parts of hard monomer, 1 - 4 parts of initiator, 30 - 60 parts of deionized water.

3. The waterborne UV insulating and curable adhesive with high adhesion performance according to claim 2, wherein The epoxy resin is one or several of epoxy resin E20, E21, E51; The functional monomer is one or several of 1 - vinyl - 2 - pyrrolidone, cyclic polymerizable monomer, methacrylic acid; The soft monomer is one or several of 2 - ethylhexyl acrylate, butyl acrylate, lauryl acrylate, methoxyethyl acrylate; The hard monomer is one or several of 2 - hydroxyethyl acrylate, 4 - hydroxybutyl acrylate, glycidyl methacrylate; The initiator is benzoyl peroxide.

4. The UV insulating and curable adhesive for the high adhesion performance aqueous system according to claim 2, wherein The waterborne epoxy modified acrylic emulsion is prepared by the following method: S1. Add the epoxy resin into n - butanol, and heat up to 120 °C while stirring; S2. Mix the soft monomer, hard monomer, functional monomer and initiator evenly to obtain a reaction solution; S3. Drop the reaction solution into the mixture obtained in step S1, react at 120 °C for 2.5 h to obtain waterborne epoxy modified acrylic acid, cool down to 50 °C, add N,N - dimethylethanolamine to neutralize and form salt, and keep warm for half an hour; S4. Drop deionized water into the waterborne epoxy modified acrylic acid at a stirring speed of 3000 r / min, and disperse fully to obtain the waterborne epoxy modified acrylic emulsion.

5. The waterborne UV insulating and curable adhesive with high adhesion performance according to claim 1, characterized in that, The modified carboxymethyl cellulose is obtained by reacting the following raw materials by weight parts: 60 parts of carboxymethyl cellulose, 1000 parts of deionized water, 3 parts of potassium persulfate, 30 parts of methyl methacrylate.

6. The water-based system UV insulating and curable adhesive with high adhesion performance according to claim 5, characterized in that, The preparation method of the modified carboxymethyl cellulose is: S1: Add carboxymethyl cellulose and deionized water into a four - necked flask, pass nitrogen and heat up to 80 °C and stir fully to dissolve; S2: After stirring for 30 min, add potassium persulfate and keep warm for 10 min; S3: Add methyl methacrylate, keep warm for 3 h and then cool down to obtain the modified carboxymethyl cellulose.

7. The water-based system UV insulating and curable adhesive with high adhesion performance according to claim 1, characterized in that, The waterborne epoxy resin is one or several of EXA - 8420 - 60W of DIC, EPICLON H - 502 - 42W of DIC, SK2132 waterborne epoxy ester resin of ShuaiKe Chemical Industry; The photoinitiator is photoinitiator 2959; The flame retardant is one or more of aluminum diethyl phosphite or melamine cyanurate.

8. A preparation method of a high - adhesion water - based system UV insulating curing glue as described in any one of claims 1 - 7, comprising the following steps: Under a light-shielded environment, mix an aqueous epoxy-modified acrylic emulsion, an aqueous epoxy resin, a modified carboxymethyl cellulose, a photoinitiator, an antioxidant, and a flame retardant, and stir evenly to obtain a high-adhesion performance aqueous system UV insulating curing adhesive.

9. A water-based system UV insulating and curable tape with high adhesion performance, characterized in that, It is prepared by the following method: Coat the high-adhesion performance aqueous system UV insulating curing adhesive on an insulating substrate, and after drying, attach a release film to the adhesive surface to obtain the high-adhesion performance aqueous system UV insulating curing tape.

10. Application of the water-based system UV insulating and curing tape with high adhesion performance as described in claim 8 in a battery pack, and the application method is: attaching the water-based system UV insulating and curing tape with high adhesion performance to the surface of the battery housing, and standing still after UV curing; the energy density of UV curing is 3000-5000 mJ / cm 2 , and the time of UV curing is 10 s - 1 min.

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