An insulating and flame-retardant coated material and its preparation method

Abstract

This application relates to the field of battery pack shell film materials. More specifically, it relates to an insulating and flame-retardant coated film material and its preparation method. An insulating and flame-retardant coated film material includes component A and component B, and the mass ratio of component A to component B is 100:(5 - 10); Component A includes the following raw materials: UV epoxy dual-curing resin, UV moisture dual-curing resin, CTFA monomer, 2-hydroxyethyl methacrylate phosphate, spherical silica powder, coconut shell fiber, tremella extract, mugwort leaf extract, photoinitiator, coupling agent, dispersant, pigment, halogen-free flame retardant, solvent; Component B is a curing agent. The coated film material of this application has good properties such as toughness, insulation, flame retardance, aging resistance, electrolyte resistance, gasoline resistance, etc.; compared with the blue film, this film layer is tough, flame retardant, and aging resistant; compared with spraying, the film coating process of this film layer is simple, only need to add UV curing equipment, the film thickness is uniform, and there is no VOC emission.

Description

Technical Field

[0001] This application relates to the field of battery pack shell film materials, and more specifically, to an insulating and flame-retardant laminated material and its preparation method. Background Art

[0002] In the context of the rapid development of battery pack manufacturing and safety protection technologies, the insulation and flame-retardant properties of the battery pack shell have become important indicators for measuring its safety performance. The traditional approach is to cover a layer of PET film (commonly known as the blue film) on the battery pack shell as an insulating layer in order to prevent current leakage and short circuits. However, in practical applications, this blue film has exposed a series of defects that cannot be ignored.

[0003] As an insulating layer, the primary problem with the blue film lies in its flammability. The battery pack may generate high temperatures during abnormal operating conditions, even triggering a fire. The flammable nature of the blue film makes it unable to effectively block the spread of fire in such an environment, thus increasing the safety risks of the battery pack.

[0004] To overcome the defects of the blue film, the industry has tried to improve it by spraying an insulating coating. However, this method also has many deficiencies. Firstly, the spraying process is difficult to ensure the uniformity of the film thickness, resulting in the coating being too thick or too thin in some areas, affecting the insulation effect. Secondly, spraying the insulating coating needs to be carried out after the battery pack's battery cells are assembled, which undoubtedly increases the complexity and cost of the process. More importantly, since the outer shell coating cannot withstand high-temperature baking after painting, this greatly limits the types and process options of the coating. Many high-performance coating materials are excluded due to their inability to adapt to low-temperature curing conditions, thus restricting the further development of battery pack insulation protection technologies. Summary of the Invention

[0005] To solve the above problems, this application provides an insulating and flame-retardant laminated material and its preparation method.

[0006] In a first aspect, this application provides an insulating and flame-retardant laminated material, adopting the following technical solution:

[0007] An insulating and flame-retardant laminated material, comprising component A and component B, and the mass ratio of component A to component B is 100:(5 - 10);

[0008] Component A, by mass percentage, includes the following raw materials: 30-40% UV epoxy dual-curing resin, 15-20% UV moisture dual-curing resin, 10-15% CTFA monomer, 2-5% 2-hydroxyethyl methacrylate phosphate, 5-10% spherical silica powder, 1-5% coconut shell fiber, 1-5% tremella extract, 1-5% mugwort extract, 2-5% photoinitiator, 1-3% coupling agent, 0.1-3% dispersant, 0.1-1% pigment, 1-5% halogen-free flame retardant, and solvent;

[0009] Component B is a curing agent.

[0010] The specific insulating and flame-retardant laminated material provided by this application is first coated on a release film and pre-cured, and then covered on the surface of workpieces such as the battery pack housing, and cured by a UV lamp to form a protective film.

[0011] By adopting the above technical solution, first of all, the UV epoxy dual-curing resin and the UV moisture dual-curing resin are selected and matched with each other, which can effectively balance the curing speed of the coating. The UV curing speed is fast, but it mainly acts on the surface of the coating; the moisture curing speed is slow, but it can penetrate into the interior of the coating. This balance enables the coating to maintain rapid curing while also achieving full curing of the internal structure, thereby avoiding quality problems caused by uneven curing of the coating. The synergistic effect of the UV epoxy dual-curing resin and the UV moisture dual-curing resin can also improve the uniformity of the coating. The preliminary cross-linked network structure formed during the UV curing stage provides a good foundation for the moisture curing stage, enabling the moisture curing process to proceed more evenly. This helps to reduce defects such as bubbles and cracks in the coating, and improve the overall quality and fluidity of the coating.

[0012] Moreover, with the combined action of spherical silica powder, coconut shell fiber, tremella extract, and mugwort extract, the spherical silica powder is embedded in the network structure of the coconut shell fiber, effectively reducing the frictional resistance between particles; while the tremella extract and mugwort extract can also adhere to the surface of the coconut shell fiber, and the four form a special structure in the system. This special structure has high thermal stability and is not easily combustible, enabling the laminated material to maintain a stable structure under high temperature or flame action, absorb and disperse heat, delay or prevent the combustion process, and exhibit good flame retardant performance. In addition, it also has excellent insulating performance, which can effectively increase the resistivity of the laminated material and reduce the possibility of current passing through. The good distribution of this special structure in the system of the UV epoxy dual-curing resin and the UV moisture dual-curing resin effectively guarantees the performance of the laminated material.

[0013] Preferably, by mass percentage, the UV epoxy dual-curing resin is 35-38%, and the UV moisture dual-curing resin is 16-18%.

[0014] By adopting the above technical solutions and further defining the dosage and cooperation relationship in the systems of UV epoxy dual-curing resin and UV moisture dual-curing resin, the laminating material can have sufficient adhesion and hardness while maintaining good fluidity, further ensuring the good flame retardancy and insulation performance of the laminating material.

[0015] Preferably, by mass percentage, the spherical silica powder is 6-8%, the coconut shell fiber is 2.5-4%, the tremella extract is 1-3%, and the mugwort extract is 1.5-3.5%.

[0016] Preferably, the photoinitiator includes at least one or a mixture of more than one of TPO photoinitiator and 819 photoinitiator.

[0017] Preferably, the halogen-free flame retardant includes at least one or a mixture of more than one of magnesium hydroxide, aluminum hydroxide, hydrotalcite, and ammonium polyphosphate.

[0018] Preferably, the solvent includes at least one or a mixture of more than one of tetrahydrofuran, acetone, chloroform, dichloromethane, and ethyl acetate.

[0019] In a second aspect, the present application provides a preparation method of an insulating and flame-retardant laminating material, adopting the following technical solutions: A preparation method of an insulating and flame-retardant laminating material includes the following steps:

[0020] Step 1: Prepare a mixture:

[0021] Step 1a: Dissolve the tremella extract and the mugwort extract in water to obtain a treatment solution;

[0022] Step 1b: Put the spherical silica powder and the coconut shell fiber into the treatment solution and stir to mix;

[0023] Step 1c: Microwave-treat the material in Step 1b under the condition of 200-250W for 5-10 minutes, and then soak for 1-2 hours;

[0024] Step 1d: Perform solid-liquid separation. After drying the solid part, a mixture is obtained;

[0025] Step 2: Mix various raw materials of component A until uniform to obtain component A;

[0026] Step 3: Mix component A and the low-temperature epoxy curing agent in proportion until uniform to obtain the insulating and flame-retardant laminating material.

[0027] By adopting the above technical solutions, the treatment solution in which the tremella extract and the mugwort extract are dissolved in water can effectively adhere to the surfaces of the spherical silica powder and the coconut shell fiber, further strengthening the connection relationship among the four, and generating a special cooperation effect to form a special structure, which can well improve the performance of the laminating material.

[0028] During the actual use of the coated film material provided in this application, it is first fixed on the release film by pre-curing, and then covered on the surface of the workpiece and cured by irradiating with a UV lamp. This effectively solves the limitation of the coated film material due to the inability of the shell coating to withstand high-temperature baking after painting. Moreover, before UV curing, the coated film material of this application is a material with flexibility and strength, which can well adapt to workpieces of various shapes and completely cover them, making the insulation and flame retardant properties more stable everywhere on the surface of the workpiece.

[0029] In summary, this application has the following beneficial effects:

[0030] 1. The coated film material of this application is pre-coated on the release film, maintaining flexibility and a certain strength before the coating is completed, so that the coated film material can completely cover various irregular structural parts. After the coating is completed, it is cured by irradiating with a UV lamp, making the coating layer cure and become tough. At the same time, this coated film material has good properties such as toughness, insulation, flame retardancy, aging resistance, electrolyte resistance, and gasoline resistance; compared with the blue film, this film layer is tough, flame retardant, and aging resistant; compared with spraying, the coating process of this film layer is simple, only need to add UV curing equipment, the film thickness is uniform, and there is no VOC emission.

[0031] 2. In this application, it is preferably to use UV epoxy dual-curing resin and UV moisture dual-curing resin in combination, which can effectively balance the curing speed of the coating, improve the uniformity of the coating, help reduce defects such as bubbles and cracks in the coating, and improve the overall quality and fluidity of the coating.

[0032] 3. With the combined action of spherical silica powder, coconut shell fiber, tremella extract, and mugwort leaf extract in this application, a special structure is formed among the four in the system. It endows the coated film material with high thermal stability, low flammability, and excellent insulation performance. Specific Embodiments

[0033] The following further elaborates on this application with reference to examples.

[0034] The raw materials used in the following examples and comparative examples are all commercially available products.

[0035] Examples

[0036] Example 1

[0037] An insulating and flame-retardant coated film material, including component A and component B, and the mass ratio of component A to component B is 100:8.

[0038] Component A includes the following raw materials: UV epoxy dual-curing resin, UV moisture dual-curing resin, CTFA monomer, 2-hydroxyethyl methacrylate phosphate, spherical silica powder, coconut shell fiber, tremella extract, mugwort leaf extract, photoinitiator, coupling agent, dispersant, pigment, halogen-free flame retardant, solvent.

[0039] The UV epoxy dual-curing resin is commercially available and purchased from Axalta, with the model number 605 / 20.

[0040] The UV moisture dual-curing resin is commercially available and purchased from Guangzhou Haoyi New Materials Technology Co., Ltd., with the model number SR-2345.

[0041] The CTFA monomer is commercially available and purchased from Jiangsu Minglin Chemical Technology Co., Ltd.

[0042] The tremella extract is commercially available and purchased from Xi'an Allbio Technology Co., Ltd.

[0043] The mugwort leaf extract is commercially available and purchased from Shaanxi Bolin Biotechnology Co., Ltd.

[0044] The photoinitiators are TPO photoinitiator and 819 photoinitiator.

[0045] The coupling agent is a silane coupling agent, KH-560.

[0046] The dispersant is Lubrizol Solsperse 32500.

[0047] The pigment is a commercially available pigment blue.

[0048] The halogen-free flame retardant is commercially available magnesium hydroxide.

[0049] The solvent is acetone.

[0050] The specific dosage of each raw material in component A is shown in Table 1.

[0051] Component B is a commercially available epoxy low-temperature curing agent. In this example, it is purchased from Guangzhou Gelin New Materials Co., Ltd., with the model number GL1820.

[0052] This application also provides a preparation method of an insulating and flame-retardant coated film material, including the following steps:

[0053] Step 1: Prepare a mixture:

[0054] Step 1a: Dissolve the tremella extract and the mugwort leaf extract evenly in water to obtain a treatment solution.

[0055] The total mass of the tremella extract and the mugwort leaf extract and the mass of water are 1:10.

[0056] Step 1b: Put spherical silica powder and coconut shell fiber into the treatment solution and stir and mix for 30 min under the condition of 550 r / min.

[0057] Step 1c: Microwave-treat the material in Step 1b for 7 min under the condition of 230 W. After the microwave treatment, let it stand and soak for 1.5 h.

[0058] Step 1d: Perform solid-liquid separation on the material in Step 1c. After drying the solid part in hot air until constant weight, a mixture is obtained.

[0059] Step 2: Mix UV epoxy dual-curing resin, UV moisture dual-curing resin, CTFA monomer, 2-hydroxyethyl methacrylate phosphate, the mixture, photoinitiator, coupling agent, dispersant, pigment, halogen-free flame retardant, and solvent uniformly to obtain Component A.

[0060] Step 3: Mix Component A and a low-temperature epoxy curing agent in proportion uniformly to obtain an insulating and flame-retardant laminating material.

[0061] When the insulating and flame-retardant laminating material is applied to a workpiece, the operation method includes the following steps:

[0062] Step A: Roll coat the insulating and flame-retardant laminating material onto a special release film using a special roll coating device, and control the dry film thickness to be 120 - 180 μm.

[0063] Step B: Pre-cure at 120°C for 1 minute. After pre-curing, the mixed film layer has a certain tensile strength and flexibility.

[0064] Step C: Cover the mixed film layer on the surface of the workpiece using a film laminating device similar to a common blue film.

[0065] Step D: The workpiece is cured by a microwave electrodeless UV lamp with an energy of 3000 - 4000 mj / cm 2 to completion.

[0066] Example 2

[0067] An insulating and flame-retardant laminating material, which is different from that in Example 1 in that

[0068] in Component A, the dosages of each raw material are different, as shown in Table 1 for details.

[0069] Example 3

[0070] An insulating and flame-retardant laminating material, which is different from that in Example 1 in that the mass ratio of Component A to Component B is 100:5.

[0071] in Component A, the dosages of each raw material are different, as shown in Table 1 for details.

[0072] in Component A, the halogen-free flame retardant is aluminum hydroxide, and the solvent is dichloromethane.

[0073] A preparation method of an insulating and flame-retardant laminating material, which is different from that in Example 1 in that some parameters for preparing the mixture in Step 1 are different, specifically as follows:

[0074] Step 1a: Dissolve tremella extract and mugwort leaf extract uniformly in water to obtain a treatment solution.

[0075] The total mass of tremella extract and mugwort leaf extract is 1:10 with the mass of water.

[0076] Step 1b: Put spherical silica powder and coconut shell fiber into the treatment liquid, and stir and mix for 30 min under the condition of 500 r / min.

[0077] Step 1c: Microwave-treat the material in Step 1b for 10 min under the condition of 200 W. After the microwave treatment, let it stand and soak for 2 h.

[0078] Step 1d: Perform solid-liquid separation on the material in Step 1c. After drying the solid part in hot air until constant weight, a mixture is obtained.

[0079] Example 4

[0080] An insulating and flame-retardant coated material, which is different from that in Example 1 in that the mass ratio of component A to component B is 100:10.

[0081] In component A, the dosages of each raw material are different, as shown in Table 1 for details.

[0082] In component A, the halogen-free flame retardant is ammonium polyphosphate and the solvent is tetrahydrofuran.

[0083] A preparation method of an insulating and flame-retardant coated material, which is different from that in Example 1 in that some parameters for preparing the mixture in Step 1 are different, specifically as follows:

[0084] Step 1a: Dissolve tremella extract and mugwort leaf extract evenly in water to obtain a treatment liquid.

[0085] The total mass of tremella extract and mugwort leaf extract is 1:10 with the mass of water.

[0086] Step 1b: Put spherical silica powder and coconut shell fiber into the treatment liquid, and stir and mix for 30 min under the condition of 600 r / min.

[0087] Step 1c: Microwave-treat the material in Step 1b for 5 min under the condition of 250 W. After the microwave treatment, let it stand and soak for 1 h.

[0088] Step 1d: Perform solid-liquid separation on the material in Step 1c. After drying the solid part in hot air until constant weight, a mixture is obtained.

[0089] Table 1

[0090]

[0091]

[0092] Comparative example

[0093] Comparative Example 1

[0094] An insulating and flame-retardant coated film material, which is different from Example 1 in that the UV epoxy dual-curing resin is 16 kg and the UV moisture dual-curing resin is 35 kg.

[0095] Comparative Example 2

[0096] An insulating and flame-retardant coated film material, which is different from Example 1 in that the tremella extract is replaced with aloe extract.

[0097] The aloe extract is purchased from Shaanxi Bolin Biotechnology Co., Ltd.

[0098] Comparative Example 3

[0099] An insulating and flame-retardant coated film material, which is different from Example 1 in that the mugwort extract is replaced with poria cocos extract.

[0100] The poria cocos extract is purchased from Fufeng Snow Biotech Co., Ltd.

[0101] Comparative Example 4

[0102] An insulating and flame-retardant coated film material, which is different from Example 1 in that the tremella extract and the mugwort extract are replaced with a solvent.

[0103] Comparative Example 5

[0104] An insulating and flame-retardant coated film material, which is different from Example 1 in that the coconut shell fiber is replaced with jute fiber.

[0105] Comparative Example 6

[0106] A preparation method of an insulating and flame-retardant coated film material, which is different from Example 1 in that the prior preparation of the mixture in Step 1 is omitted, and the specific steps are as follows:

[0107] Step 1: Mix the UV epoxy dual-curing resin, UV moisture dual-curing resin, CTFA monomer, 2-hydroxyethyl methacrylate phosphate, spherical silica powder, coconut shell fiber, tremella extract, mugwort extract, photoinitiator, coupling agent, dispersant, pigment, halogen-free flame retardant, and solvent until uniform to obtain Component A.

[0108] Step 2: Mix Component A and the low-temperature epoxy curing agent in proportion until uniform to obtain the insulating and flame-retardant coated film material.

[0109] Performance Detection Test

[0110] 1. Flame Retardancy: Refer to GB / T 12441-2005 "Decorative Fire Retardant Coatings" to detect the insulating and flame-retardant coated film materials of Examples 1-4 and Comparative Examples 1-6, and record the flame resistance time in Table 2.

[0111] 2. Insulation performance: Referring to GB / T 1408.1-2006 "Test Method for Electrical Strength of Insulating Materials", the insulating and flame-retardant coated films of Examples 1-4 and Comparative Examples 1-6 were tested, and the breakdown voltages were recorded in Table 2.

[0112] 3. Appearance: Referring to the operation method described in Example 1 for preparing the test sample when the insulating and flame-retardant coated film is applied to the workpiece, the surface of the coated film layer formed by curing on the test sample was observed with the naked eye to check whether it is flat and whether there are defects such as air bubbles and cracks, and the results were recorded in Table 2.

[0113] Table 2

[0114]

[0115] According to the test data in Table 2, when the insulating and flame-retardant coated films of Examples 1-4 are applied to the surface of the workpiece and cured, they are very flat and there are no defects such as air bubbles and cracks on the surface. Thanks to the fact that the insulating and flame-retardant coated films of Examples 1-4 still retain a certain degree of flexibility and hardness during pre-curing, they can fit the workpiece more comprehensively, so as to fully protect the surface of the workpiece. In the appearance inspection of Comparative Examples 1 and 6, the surface flatness is inferior to that of Examples 1-4, and there are also a small number of air bubble defects. This is because in Comparative Example 1, the specific dosage ratio of the UV epoxy dual-curing resin and the UV moisture dual-curing resin in the system was changed, resulting in an affected curing effect. The change in the whole system also affected the mixing of the mixture, thus resulting in poor appearance of Comparative Example 1. In Comparative Example 6, the preparation of the mixture was omitted, and the spherical silica powder, coconut shell fiber, tremella extract, and mugwort extract were directly mixed with the other raw materials, so that the spherical silica powder, coconut shell fiber, tremella extract, and mugwort extract could not form a special structure and could not be well distributed in the system, resulting in a decline in performance and poor appearance.

[0116] Based on Example 1, in Comparative Examples 2-5, the spherical silica powder, coconut shell fiber, tremella extract, and mugwort extract were replaced with other raw materials, so that the special combination of the spherical silica powder, coconut shell fiber, tremella extract, and mugwort extract could not be produced, and then the insulating and flame-retardant effects of the coated film material were poor, showing a lower combustion resistance time and a lower breakdown voltage. It shows that there is a special cooperative effect among the spherical silica powder, coconut shell fiber, tremella extract, and mugwort extract. Randomly destroying the combination or preparation method of the four will cause this special cooperative effect not to occur, thus making it impossible for the coated film material to achieve good flame-retardant and insulating effects.

[0117] This specific embodiment is only an interpretation of the present application and does not limit the present application. After reading this specification, those skilled in the art can make modifications to this embodiment without creative contributions as needed, but as long as it is within the scope of the claims of the present application, it is protected by the patent law.

Claims

1. An insulating and flame-retardant coated material, characterized in that It includes Component A and Component B, and the mass ratio of Component A to Component B is 100:(5 - 10); Component A, by mass percentage, includes the following raw materials: 30 - 40% UV epoxy dual-curing resin, 15 - 20% UV moisture dual-curing resin, 10 - 15% CTFA monomer, 2 - 5% 2-hydroxyethyl methacrylate phosphate, 5 - 10% spherical silica powder, 1 - 5% coconut shell fiber, 1 - 5% tremella extract, 1 - 5% mugwort leaf extract, 2 - 5% photoinitiator, 1 - 3% coupling agent, 0.1 - 3% dispersant, 0.1 - 1% pigment, 1 - 5% halogen-free flame retardant, and solvent; Component B is a curing agent; The preparation method of the insulating and flame-retardant film material includes the following steps: Step 1: Prepare a mixture: Step 1a: Dissolve the tremella extract and mugwort leaf extract in water to obtain a treatment solution; Step 1b: Put the spherical silica powder and coconut shell fiber into the treatment solution and stir to mix; Step 1c: Microwave-treat the material in Step 1b for 5 - 10 min under the condition of 200 - 250 W, and then soak for 1 - 2 h; Step 1d: Perform solid-liquid separation, and after drying the solid part, obtain a mixture; Step 2: Mix various raw materials of Component A until uniform to obtain Component A; Step 3: Mix Component A and the curing agent in proportion until uniform to obtain the insulating and flame-retardant film material.

2. The insulating and flame-retardant coated material according to claim 1, wherein: By mass percentage, the UV epoxy dual-curing resin is 35 - 38%, and the UV moisture dual-curing resin is 16 - 18%.

3. The insulating and flame-retardant coated material according to claim 1, wherein: By mass percentage, the spherical silica powder is 6 - 8%, the coconut shell fiber is 2.5 - 4%, the tremella extract is 1 - 3%, and the mugwort leaf extract is 1.5 - 3.5%.

4. The insulating and flame-retardant coated material according to claim 1, characterized in that: The photoinitiator includes at least one or a mixture of more than one of TPO photoinitiator and 819 photoinitiator.

5. The insulating and flame-retardant coated material according to claim 4, characterized in that: The photoinitiator is TPO photoinitiator and 819 photoinitiator, and the mass ratio of TPO photoinitiator to 819 photoinitiator is (0.8 - 1.2):(0.8 - 1.2).

6. The insulating and flame-retardant coated material according to claim 1, wherein: The halogen-free flame retardant includes at least one or a mixture of more than one of magnesium hydroxide, aluminum hydroxide, hydrotalcite, and ammonium polyphosphate.

7. The insulating and flame-retardant coated material according to claim 1, wherein: In Step 1b, when putting the spherical silica powder and coconut shell fiber into the treatment solution, stir and mix under the condition of 500 - 600 r / min.

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