Insulating flame-retardant coating material and preparation method thereof

Abstract

The invention relates to the field of battery pack shell membrane materials, in particular to an insulating flame-retardant membrane material and a preparation method thereof. The insulating flame-retardant coating material comprises a component A and a component B, and the mass ratio of the component A to the component B is 100: (5-10); the component A comprises the following raw materials: UV epoxy dual-curing resin, UV moisture dual-curing resin, a CTFA monomer, 2-hydroxyethyl methacrylate phosphate, spherical silica powder, coconut fiber, a tremella extract, a folium artemisiae argyi extract, a photoinitiator, a coupling agent, a dispersing agent, a pigment, a halogen-free flame retardant and a solvent; and the component B is a curing agent. The coating material disclosed by the invention has good properties of toughness, insulation, flame retardance, aging resistance, electrolyte resistance, gasoline resistance and the like; compared with a blue film, the film layer is tough, flame-retardant and aging-resistant; compared with spraying, the coating process of the film layer is simple, only UV curing equipment needs to be additionally arranged, the film thickness is uniform, and VOC emission is avoided.

Description

Technical Field

[0001] The present application relates to the field of battery pack outer shell film materials, and more specifically, it relates to an insulating flame-retardant coating material and a preparation method thereof. Background Art

[0002] With the rapid development of battery pack manufacturing and safety protection technology, the insulation and flame retardant properties of battery pack shells have become important indicators for measuring their safety performance. The traditional practice is to cover the battery pack shell with a layer of PET film (commonly known as blue film) as an insulating layer to prevent current leakage and short circuit. However, in actual applications, this blue film exposes a series of defects that cannot be ignored.

[0003] As an insulating layer, the primary problem with the blue film is its flammability. The battery pack may generate high temperatures or even cause a fire under abnormal working conditions. The flammable nature of the blue film makes it unable to effectively prevent the spread of fire in such an environment, thus increasing the safety risk of the battery pack.

[0004] In order to overcome the defects of blue film, the industry has tried to improve it by spraying insulating coating. However, this method also has many shortcomings. First, the spraying process is difficult to ensure the uniformity of 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 cells of the battery pack 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 of coatings and process selection. Many high-performance coating materials are excluded because they cannot adapt to low-temperature curing conditions, which limits the further development of battery pack insulation protection technology. Summary of the invention

[0005] In order to solve the above problems, the present application provides an insulating flame-retardant coating material and a preparation method thereof.

[0006] In a first aspect, the present application provides an insulating flame-retardant coating material, which adopts the following technical solution: An insulating flame-retardant coating material comprises a component A and a component B, wherein the mass ratio of the component A to the component B is 100:(5-10); Component A includes the following raw materials in percentage by mass: 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% wormwood extract, 2-5% photoinitiator, 1-3% coupling agent, 0.1-3% dispersant, 0.1-1% pigment, 1-5% halogen-free flame retardant, solvent; Component B is a curing agent.

[0007] The specific insulating flame-retardant coating material provided in the present application is first coated on a release film and pre-cured, and then coated on the surface of a workpiece such as a battery pack shell, and cured by a UV lamp to form a protective film.

[0008] By adopting the above technical solution, first of all, the UV epoxy dual-cure resin and the UV moisture dual-cure resin are selected to cooperate with each other, which can effectively balance the curing speed of the coating. UV curing speed is fast, but it mainly acts on the surface of the coating; moisture curing speed is slow, but it can penetrate into the interior of the coating. This balance allows the coating to fully cure the internal structure while maintaining rapid curing, thereby avoiding quality problems caused by uneven curing of the coating. The synergistic effect of UV epoxy dual-cure resin and UV moisture dual-cure resin can also improve the uniformity of the coating. The preliminary cross-linked network structure formed in the UV curing stage provides a good foundation for the moisture curing stage, allowing 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.

[0009] Moreover, with the cooperation of spherical silicon powder, coconut shell fiber, Tremella extract and Artemisia argyi extract, spherical silicon powder is embedded in the network structure of coconut shell fiber, effectively reducing the friction resistance between particles; Tremella extract and Artemisia argyi extract can also be attached to the surface of coconut shell fiber, and the four form a special structure between the system. This special structure has the characteristics of high thermal stability and non-flammability, so that the coating material can maintain structural stability under high temperature or flame, absorb and disperse heat, delay or prevent the combustion process, and show good flame retardant properties. In addition, it also has excellent insulation properties, which can effectively improve the resistivity of the coating material and reduce the possibility of current passing. The good distribution of this special structure in the system of UV epoxy dual-curing resin and UV moisture dual-curing resin effectively guarantees the performance of the coating material.

[0010] Preferably, in terms of mass percentage, the UV epoxy dual-curing resin is 35-38%, and the UV moisture dual-curing resin is 16-18%.

[0011] By adopting the above technical scheme, the dosage relationship in the system of UV epoxy dual-curing resin and UV moisture dual-curing resin is further limited, so that the coating material can have sufficient adhesion and hardness while maintaining good fluidity, further ensuring the good flame retardant and insulating properties of the coating material.

[0012] Preferably, in terms of mass percentage, the spherical silicon powder is 6-8%, the coconut shell fiber is 2.5-4%, the tremella extract is 1-3%, and the wormwood extract is 1.5-3.5%.

[0013] Preferably, the photoinitiator includes at least a mixture of one or more of TPO photoinitiator and 819 photoinitiator.

[0014] Preferably, the halogen-free flame retardant includes at least one or more of magnesium hydroxide, aluminum hydroxide, hydrotalcite, and ammonium polyphosphate.

[0015] Preferably, the solvent includes at least one or more of tetrahydrofuran, acetone, chloroform, dichloromethane and ethyl acetate.

[0016] In a second aspect, the present application provides a method for preparing an insulating flame-retardant coating material, which adopts the following technical solution: A method for preparing an insulating flame-retardant coating material comprises the following steps: Step 1: Prepare the mixture: Step 1a: dissolving the Tremella fuciformis extract and the Artemisia argyi extract in water to obtain a treated solution; Step 1b: Add spherical silicon powder and coconut shell fiber into the treatment liquid and stir to mix; Step 1c: subjecting the material of step 1b to microwave treatment at 200-250W for 5-10min, and then soaking for 1-2h; Step 1d: solid-liquid separation, and drying the solid part to obtain a mixture; Step 2: Mix various raw materials of component A until uniform, to obtain component A; Step 3: Component A and the low-temperature epoxy curing agent are mixed uniformly according to a certain proportion to obtain an insulating flame-retardant coating material.

[0017] By adopting the above technical scheme, the treatment liquid in which Tremella extract and Artemisia argyi extract are dissolved in water can effectively adhere to the surface of spherical silica powder and coconut shell fiber, so that the connection relationship between the four is further strengthened, and a special coordination effect is produced, forming a special structure to well improve the performance of the coating material.

[0018] The coating material provided by the present application is first fixed on the release film by pre-curing in actual use, and then covered on the surface of the workpiece and cured by UV light irradiation. This effectively solves the limitation of the coating material on the shell coating that cannot withstand high-temperature baking after painting. In addition, the coating material of the present application is a flexible and strong material before UV curing, which can adapt well to workpieces of various shapes and completely cover them, making the insulation and flame retardant properties of the workpiece surface more stable.

[0019] In summary, this application has the following beneficial effects: 1. This application pre-coats the coating material on the release film, and maintains flexibility and a certain strength before the coating is completed, so that the coating material can completely cover various irregular structural parts. After the coating is completed, it is cured by UV light, so that the coating layer is cured and tough. At the same time, the coating material has good properties such as toughness, insulation and flame retardancy, aging resistance, electrolyte resistance, and gasoline resistance; compared with the blue film, the film layer is tough, flame retardant, and aging resistant; compared with spraying, the film layer coating process is simple, only UV curing equipment needs to be added, the film thickness is uniform, and there is no VOC emission.

[0020] 2. In this application, it is preferred to use UV epoxy dual-curing resin and UV moisture dual-curing resin in combination with each other, 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.

[0021] 3. In the present application, spherical silicon powder, coconut shell fiber, Tremella extract and Artemisia argyi extract are used together to form a special structure between the four systems, which endows the coating material with high thermal stability, non-flammability and excellent insulation performance. DETAILED DESCRIPTION

[0022] The present application is further described in detail below in conjunction with embodiments.

[0023] The raw materials used in the following examples and comparative examples are all commercially available products. Example

[0024] Example 1 An insulating flame-retardant coating material comprises a component A and a component B, wherein the mass ratio of the component A to the component B is 100:8.

[0025] 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, wormwood extract, photoinitiator, coupling agent, dispersant, pigment, halogen-free flame retardant, and solvent.

[0026] UV epoxy dual-curing resin is commercially available from Allnex, model 605 / 20.

[0027] The UV-moisture dual-curing resin is commercially available from Guangzhou Haoyi New Materials Technology Co., Ltd., model number SR-2345.

[0028] CTFA monomer was commercially available from Jiangsu Minglin Chemical Technology Co., Ltd.

[0029] Tremella fuciformis extract was purchased from Xi'an Anao Biotechnology Co., Ltd. Artemisia argyi extract was commercially available from Shaanxi Bolin Biotechnology Co., Ltd.

[0030] The photoinitiators are TPO photoinitiator and 819 photoinitiator.

[0031] The coupling agent is silane coupling agent, KH-560.

[0032] The dispersant was Lubrizol Solsperse 32500.

[0033] The pigment is commercially available pigment blue.

[0034] The halogen-free flame retardant is commercially available magnesium hydroxide.

[0035] The solvent is acetone.

[0036] The specific amounts of each raw material in component A are shown in Table 1.

[0037] Component B is a commercially available epoxy low-temperature curing agent, which in this embodiment was purchased from Guangzhou Green New Materials Co., Ltd., model GL1820.

[0038] The present application also provides a method for preparing an insulating flame-retardant coating material, comprising the following steps: Step 1: Prepare the mixture: Step 1a: Dissolve the Tremella fuciformis extract and the Artemisia argyi extract uniformly in water to obtain a treated solution.

[0039] The total mass of Tremella fuciformis extract and Artemisia argyi extract to the mass of water is 1:10.

[0040] Step 1b: Add spherical silicon powder and coconut shell fiber into the treatment solution and stir and mix at 550 r / min for 30 minutes.

[0041] Step 1c: subject the material of step 1b to microwave treatment for 7 min at 230 W. After the microwave treatment, allow the material to stand and soak for 1.5 h.

[0042] Step 1d: performing solid-liquid separation on the material of step 1c, and drying the solid part by hot air to constant weight to obtain a mixture.

[0043] Step 2: Mix the UV epoxy dual-cure resin, the UV moisture dual-cure resin, the CTFA monomer, the 2-hydroxyethyl methacrylate phosphate, the mixture, the photoinitiator, the coupling agent, the dispersant, the pigment, the halogen-free flame retardant, and the solvent until uniform, to obtain component A.

[0044] Step 3: Component A and the low-temperature epoxy curing agent are mixed uniformly according to a certain proportion to obtain an insulating flame-retardant coating material.

[0045] When the insulating flame retardant coating material is applied to a workpiece, the operation method includes the following steps: Step A: Use a special roller coating device to roll the insulating flame retardant coating material onto the special release film, and control the dry film thickness to 120-180um.

[0046] Step B: pre-curing at 120°C / 1min. After pre-curing, the mixed film layer has certain tensile strength and flexibility.

[0047] Step C: Use a similar common blue film coating device to coat the mixed film layer on the surface of the workpiece.

[0048] Step D: The workpiece is subjected to 3000-4000mj / cm 2 The energy is cured by microwave electrodeless UV lamp.

[0049] Example 2 An insulating flame-retardant coating material, which is different from Example 1 in that: In component A, the dosage of each raw material is different, see Table 1 for details.

[0050] Example 3 An insulating flame-retardant coating material, which is different from Example 1 in that the mass ratio of component A to component B is 100:5.

[0051] In component A, the dosage of each raw material is different, see Table 1 for details.

[0052] In component A, the halogen-free flame retardant is aluminum hydroxide and the solvent is dichloromethane.

[0053] A method for preparing an insulating flame-retardant coating material is different from that of Example 1 in that some parameters of the mixture prepared in step 1 are different, as follows: Step 1a: Dissolve the Tremella fuciformis extract and the Artemisia argyi extract uniformly in water to obtain a treated solution.

[0054] The total mass of Tremella fuciformis extract and Artemisia argyi extract to the mass of water is 1:10.

[0055] Step 1b: Add spherical silicon powder and coconut shell fiber into the treatment solution and stir and mix at 500 r / min for 30 minutes.

[0056] Step 1c: subject the material of step 1b to microwave treatment at 200 W for 10 min. After the microwave treatment, allow the material to stand and soak for 2 h.

[0057] Step 1d: performing solid-liquid separation on the material of step 1c, and drying the solid part by hot air to constant weight to obtain a mixture.

[0058] Example 4 An insulating flame-retardant coating material, which is different from Example 1 in that the mass ratio of component A to component B is 100:10.

[0059] In component A, the dosage of each raw material is different, see Table 1 for details.

[0060] In component A, the halogen-free flame retardant is ammonium polyphosphate and the solvent is tetrahydrofuran.

[0061] A method for preparing an insulating flame-retardant coating material is different from that of Example 1 in that some parameters of the mixture prepared in step 1 are different, as follows: Step 1a: Dissolve the Tremella fuciformis extract and the Artemisia argyi extract uniformly in water to obtain a treated solution.

[0062] The total mass of Tremella fuciformis extract and Artemisia argyi extract to the mass of water is 1:10.

[0063] Step 1b: Add spherical silicon powder and coconut shell fiber into the treatment solution and stir and mix them at 600 r / min for 30 minutes.

[0064] Step 1c: subject the material of step 1b to microwave treatment for 5 min at 250 W. After the microwave treatment, allow the material to stand and soak for 1 h.

[0065] Step 1d: performing solid-liquid separation on the material of step 1c, and drying the solid part by hot air to constant weight to obtain a mixture.

[0066] Table 1 Comparative Example Comparative Example 1 An insulating flame-retardant coating 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.

[0067] Comparative Example 2 An insulating flame-retardant coating material, which is different from Example 1 in that the Tremella extract is replaced by an aloe extract.

[0068] Aloe vera extract was purchased from Shaanxi Bolin Biotechnology Co., Ltd.

[0069] Comparative Example 3 An insulating flame-retardant coating material, which is different from Example 1 in that the wormwood leaf extract is replaced by a Poria cocos extract.

[0070] Poria cocos extract was purchased from Fufeng Snotech Biotechnology Co., Ltd.

[0071] Comparative Example 4 An insulating flame-retardant coating material, which is different from Example 1 in that the tremella extract and the wormwood extract are replaced by a solvent.

[0072] Comparative Example 5 An insulating flame-retardant coating material, which is different from Example 1 in that coconut shell fiber is replaced by jute fiber.

[0073] Comparative Example 6 A method for preparing an insulating flame-retardant coating material, which is different from Example 1 in that the advance preparation of the mixture in step 1 is omitted, and the specific steps are as follows: Step 1: Mix UV epoxy dual-cure resin, UV moisture dual-cure resin, CTFA monomer, 2-hydroxyethyl methacrylate phosphate, spherical silica powder, coconut shell fiber, tremella extract, wormwood extract, photoinitiator, coupling agent, dispersant, pigment, halogen-free flame retardant and solvent until uniform to obtain component A.

[0074] Step 2: Component A and the low-temperature epoxy curing agent are mixed uniformly according to a certain proportion to obtain an insulating flame-retardant coating material.

[0075] Performance testing 1. Flame retardant properties: The insulating flame retardant coating materials of Examples 1-4 and Comparative Examples 1-6 were tested with reference to GB / T 12441-2005 "Surface fire retardant coatings", and the flame retardant time was recorded in Table 2.

[0076] 2. Insulation performance: The insulating flame-retardant coating materials of Examples 1-4 and Comparative Examples 1-6 were tested with reference to GB / T 1408.1-2006 “Electrical strength test method for insulating materials”, and the breakdown voltage was recorded in Table 2.

[0077] 3. Appearance: Prepare the test sample by referring to the operation method described in Example 1 when the insulating flame-retardant coating material is applied to the workpiece. Visually observe whether the cured coating material layer on the surface of the test sample is flat and whether there are defects such as bubbles and cracks. The results are recorded in Table 2.

[0078] Table 2 According to the test data in Table 2, the insulating flame-retardant coating materials of Examples 1-4 are applied to the surface of the workpiece, and are very flat after curing, and there are no defects such as bubbles and cracks on the surface. Thanks to the insulating flame-retardant coating materials of Examples 1-4, they still retain a certain degree of flexibility and hardness during pre-curing, so that they are more fully adapted to the workpiece to fully protect the surface of the workpiece. In the appearance inspection, the surface flatness of Comparative Examples 1 and 6 is not as good as that of Examples 1-4, and there are also a small number of bubble defects. This is because Comparative Example 1 changes the specific dosage matching relationship of UV epoxy dual-curing resin and UV moisture dual-curing resin in the system, which affects the curing effect, and the change of the entire system also affects the mixing of the mixture, resulting in poor appearance of Comparative Example 1. Comparative Example 6 omits the preparation of the mixture, so that the spherical silicon powder, coconut shell fiber, tremella extract, and wormwood extract are directly mixed with the remaining raw materials, so that the spherical silicon powder, coconut shell fiber, tremella extract, and wormwood extract cannot form a special structure, and cannot be well distributed in the system, resulting in performance degradation and poor appearance.

[0079] Comparative Examples 2-5 are based on Example 1, but spherical silicon powder, coconut shell fiber, tremella extract, and wormwood extract are replaced with other raw materials, so that the special combination of spherical silicon powder, coconut shell fiber, tremella extract, and wormwood extract cannot be produced, and the insulation and flame retardant effects of the coating material are poor, showing a lower flame retardant time and a lower breakdown voltage. It shows that there is a special coordination effect between spherical silicon powder, coconut shell fiber, tremella extract, and wormwood extract. Any destruction of the combination or preparation method of the four will make this special coordination effect impossible, so that the coating material cannot achieve good flame retardant and insulation effects.

[0080] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. An insulating flame-retardant coating 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 includes the following raw materials in percentage by mass: 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% wormwood extract, 2-5% photoinitiator, 1-3% coupling agent, 0.1-3% dispersant, 0.1-1% pigment, 1-5% halogen-free flame retardant, solvent; Component B is a curing agent.

2. The insulating flame-retardant coating material according to claim 1, characterized in that: According to mass percentage, the UV epoxy dual-curing resin is 35-38%, and the UV moisture dual-curing resin is 16-18%.

3. The insulating flame-retardant coating material according to claim 1, characterized in that: According to mass percentage, the spherical silicon powder accounts for 6-8%, the coconut shell fiber accounts for 2.5-4%, the tremella extract accounts for 1-3%, and the wormwood extract accounts for 1.5-3.5%.

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

5. The insulating flame-retardant coating material according to claim 4, characterized in that: The photoinitiators are 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 flame-retardant coating material according to claim 1, characterized in that: The halogen-free flame retardant comprises at least one or more of magnesium hydroxide, aluminum hydroxide, hydrotalcite and ammonium polyphosphate.

7. A method for preparing the insulating flame-retardant coating material according to any one of claims 1 to 6, characterized in that: The following steps are involved: Step 1: Prepare the mixture: Step 1a: dissolving the Tremella fuciformis extract and the Artemisia argyi extract in water to obtain a treated solution; Step 1b: Add spherical silicon powder and coconut shell fiber into the treatment liquid and stir to mix; Step 1c: subjecting the material of step 1b to microwave treatment at 200-250W for 5-10min, and then soaking for 1-2h; Step 1d: solid-liquid separation, and drying the solid part to obtain a mixture; Step 2: Mix various raw materials of component A until uniform, to obtain component A; Step 3: Component A and the curing agent are mixed uniformly according to a certain proportion to obtain an insulating flame-retardant coating material.

8. The method for preparing the insulating flame-retardant coating material according to claim 7, characterized in that: In the step 1b, spherical silicon powder and coconut shell fiber are added to the treatment liquid and stirred and mixed at 500-600 r / min.

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