Thermally conductive fire extinguishing film, method of making and use thereof

Abstract

The application provides a heat-conducting fire-extinguishing film and a preparation method and application thereof, relates to the technical field of fire-extinguishing film preparation, and comprises the following steps: mixing silicon carbide particles with a particle size D 50 of 15-20 μm, silicon carbide particles with a particle size D 50 of 1-3 μm and silicon carbide whiskers to obtain a mixed filler, adding a silane coupling agent into the mixed filler according to a mass ratio of the silane coupling agent to the mixed filler of 1:10-20, stirring and uniformly mixing to obtain a composite heat-conducting filler; adding a crosslinking agent, a dispersing agent, a photoinitiator, a fire-extinguishing material and the composite heat-conducting filler into resin in sequence, uniformly mixing and preparing a heat-conducting fire-extinguishing slurry; and calendering and curing the heat-conducting fire-extinguishing slurry to obtain a heat-conducting fire-extinguishing film. The prepared heat-conducting fire-extinguishing film has excellent heat-conducting performance.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of fire extinguishing film preparation, in particular to a heat-conducting fire extinguishing film and a preparation method and application thereof. BACKGROUND

[0002] Secondary battery, also known as rechargeable battery or storage battery, refers to a battery that can be activated by charging after discharging and continue to be used. Generally, it includes a positive electrode, a negative electrode, a separator and an electrolyte. When the internal temperature of the battery is relatively high, reaching about 140℃, the separator melts, causing the positive and negative electrodes to contact, thereby triggering the battery to self-ignite.

[0003] Therefore, one of the methods to avoid battery self-ignition is to improve the heat conduction performance of the battery to reduce the internal temperature of the battery in time. In addition, if the battery can be effectively extinguished at the initial stage of self-ignition, the self-ignition can also be terminated in time. Therefore, it becomes a technical problem to be solved by those skilled in the art to provide a fire extinguishing film with excellent heat conduction performance. SUMMARY

[0004] In view of the deficiencies of the prior art, the present application provides a heat-conducting fire extinguishing film and a preparation method and application thereof, which solves the technical problem of self-ignition of energy storage devices.

[0005] To achieve the above object, the present application is realized by the following technical scheme:

[0006] On the one hand, the present application provides a preparation method of a heat-conducting fire extinguishing film, comprising the following steps:

[0007] S1, preparing a composite heat-conducting filler

[0008] Silicon carbide particles with a particle size D 50 of 15-20μm, silicon carbide particles with a particle size D 50 of 1-3μm and silicon carbide whiskers are mixed to obtain a mixed filler, a silane coupling agent is added to the mixed filler according to a mass ratio of the silane coupling agent to the mixed filler of 1:10-20, and the mixed filler is stirred and mixed uniformly to obtain a composite heat-conducting filler;

[0009] S2, preparing a heat-conducting fire extinguishing film

[0010] A crosslinking agent, a dispersing agent, a photoinitiator, a fire extinguishing material and the composite heat-conducting filler are sequentially added to the resin, and mixed uniformly to prepare a heat-conducting fire extinguishing slurry; and the heat-conducting fire extinguishing slurry is calendered and cured to obtain a heat-conducting fire extinguishing film.

[0011] Preferably, the volume ratio of the silicon carbide particles with a particle size D 50 of 15-20μm, the silicon carbide particles with a particle size D 50 of 1-3μm and the silicon carbide whiskers is 3:0.5-1.5:0.5-1.5.

[0012] Preferably, the diameter of the silicon carbide whisker is 0.2-1 μm and the length is 6-30 μm.

[0013] Preferably, the diameter of the silicon carbide whisker is 0.5 μm and the length is 15 μm.

[0014] Preferably, the particle size D 50 of the silicon carbide particles is 15 μm, the particle size D 50 of the silicon carbide particles is 1 μm, and the volume ratio of the silicon carbide whisker is 3:1:1.

[0015] Preferably, the resin comprises isooctyl acrylate, isobornyl acrylate, and polyurethane acrylate, and the mass ratio of the isooctyl acrylate, isobornyl acrylate, and polyurethane acrylate is 60-75:10-35:70-160.

[0016] In a second aspect, the present application provides a heat-conducting fire-extinguishing film prepared by the preparation method of the first aspect.

[0017] In a third aspect, the present application provides an application of the heat-conducting fire-extinguishing film prepared by the preparation method of the first aspect or the heat-conducting fire-extinguishing film of the second aspect in preventing spontaneous combustion of an energy storage device, wherein the heat-conducting fire-extinguishing film is coated on the outer circumferential surface of the energy storage device.

[0018] Compared with the prior art, the present application has the following beneficial effects:

[0019] The present application provides a preparation method of a heat-conducting fire-extinguishing film, which comprises a composite heat-conducting filler, wherein the composite heat-conducting filler comprises silicon carbide particles with a particle size D 50 of 15-20 μm, silicon carbide particles with a particle size D 50 of 1-3 μm, and silicon carbide whiskers, and the silicon carbide particles with a particle size D 50 of 15-20 μm and the silicon carbide particles with a particle size D 50 of 1-3 μm are dispersed in the silicon carbide whiskers. DETAILED DESCRIPTION

[0020] In order to make the purposes, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application are described clearly and completely. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0021] In order to better understand the above technical solutions, the above technical solutions will be described in detail below in combination with specific embodiments.

[0022] I. Preparation method

[0023] Embodiment 1

[0024] The present embodiment provides a preparation method of a heat-conducting fire extinguishing film, comprising the following steps:

[0025] S1, preparing a film-forming slurry

[0026] The isooctyl acrylate, isobornyl acrylate and polyurethane acrylate are mixed according to a mass ratio of 66:34:150, 5 parts by mass of a crosslinking agent ethylene glycol diacrylate and 3 parts by mass of a dispersant polyvinylpyrrolidone are then added thereto and uniformly mixed, and then 2.5 parts by mass of a photoinitiator benzoin ethyl ether is added to obtain a mixed base material. 100% of the mixed base material by mass is added to the mixed base material, stirred to uniformly disperse the fire extinguishing capsules in the mixed base material, and then 20 parts by mass of a composite heat-conducting filler is added and uniformly mixed to prepare a heat-conducting fire extinguishing slurry.

[0027] The composite heat-conducting filler comprises D 50 silicon carbide particles with a particle size of 15 μm, D 50 silicon carbide particles with a particle size of 1 μm, and silicon carbide whiskers with a diameter of 0.5 μm and a length of 15 μm.

[0028] The preparation method of the composite heat-conducting filler is as follows: D 50 silicon carbide particles with a particle size of 15 μm, D 50 silicon carbide particles with a particle size of 1 μm, and silicon carbide whiskers with a diameter of 0.5 μm and a length of 15 μm.

[0029] The polyurethane acrylate is a trifunctional aliphatic polyester PUA with a model number of B-369 from Guangdong Boxing New Material Technology Co., Ltd., and has a solid content wt%≥97% and a viscosity of 5000 CPS / 60℃.

[0030] The fire extinguishing capsules were purchased from Langfang Kamft New Materials Co., Ltd. as fire extinguishing and protection microcapsules.

[0031] S2, Curing into a film

[0032] The thermally conductive fire extinguishing slurry is poured into a glue tank. A first PET carrier film and a second PET carrier film are then installed on the first and second conveyor rollers of a calender. The thermally conductive fire extinguishing slurry in the glue tank is conveyed onto the second PET carrier film through a coating head and a baffle plate. Simultaneously, the first and second conveyor rollers of the calender are started, causing the first PET carrier film, the second PET carrier film, and the thermally conductive fire extinguishing slurry on the second PET carrier film to pass through the first and second conveyor rollers of the calender together. With the cooperation of the first and second conveyor rollers, the first PET carrier film, the second PET carrier film, and the thermally conductive fire extinguishing slurry in between are calendered to control the thickness of the thermally conductive fire extinguishing slurry. After the calendering process, the first PET carrier film, the second PET carrier film, and the thermally conductive fire extinguishing slurry in between enter an 80W ultraviolet lamp box. Under the action of ultraviolet light, the fire extinguishing composition solidifies to form a thermally conductive fire extinguishing film, which is then wound up by a take-up roller.

[0033] Example 2

[0034] This embodiment provides a method for preparing a thermally conductive fire extinguishing membrane, including the following steps:

[0035] S1. Preparation of film-forming slurry

[0036] Isooctyl acrylate, isoborneol acrylate, and polyurethane acrylate were mixed in a mass ratio of 60:30:140. Then, 3 parts by mass of crosslinking agent ethylene glycol diacrylate and 2 parts by mass of dispersant polyvinylpyrrolidone were added and mixed evenly. Then, 1.5 parts by mass of photoinitiator benzoyl ether were added to obtain a mixed substrate. Fire extinguishing capsules accounting for 90% of the mass of the mixed substrate were added to the mixed substrate and stirred to evenly disperse the fire extinguishing capsules in the mixed substrate. Finally, 15 parts by mass of composite thermally conductive filler were added and mixed evenly to prepare a thermally conductive fire extinguishing slurry.

[0037] The composite thermally conductive filler comprises D in a mass ratio of 3:0.5:0.5. 50 Silicon carbide particles of 18μm, D 50 Silicon carbide particles and whiskers are 3μm in size.

[0038] The preparation method of the composite thermally conductive filler is as follows: The particle size D is... 50 Silicon carbide particles of 18 μm, particle size D 50A mixed filler was obtained by mixing 3μm silicon carbide particles and silicon carbide whiskers. Silane coupling agent KH560 was added to the mixed filler at a mass ratio of 1:10, and the mixture was stirred until homogeneous to obtain a composite thermally conductive filler.

[0039] The polyurethane acrylate is a trifunctional aliphatic polyester PUA from Guangdong Boxin New Material Technology Co., Ltd., model B-369, with a solid content ≥97% wt% and a viscosity of 5000 CPS / 60℃.

[0040] The fire extinguishing capsules were purchased from Langfang Kamft New Materials Co., Ltd. as fire extinguishing and protection microcapsules.

[0041] S2, Curing into a film

[0042] The curing process is the same as in Example 1.

[0043] Example 3

[0044] This embodiment provides a method for preparing a thermally conductive fire extinguishing membrane, including the following steps:

[0045] S1. Preparation of film-forming slurry

[0046] Isooctyl acrylate, isoborneol acrylate, and polyurethane acrylate were mixed in a mass ratio of 75:15:160. Then, 8 parts by mass of crosslinking agent ethylene glycol diacrylate and 5 parts by mass of dispersant polyvinylpyrrolidone were added and mixed evenly. Then, 3.5 parts by mass of photoinitiator benzoyl ether were added to obtain a mixed substrate. Fire extinguishing capsules accounting for 100% of the mass of the mixed substrate were added to the mixed substrate and stirred to evenly disperse the fire extinguishing capsules in the mixed substrate. Then, 25 parts by mass of composite thermally conductive filler were added and mixed evenly to prepare a thermally conductive fire extinguishing slurry.

[0047] The composite thermally conductive filler comprises D in a mass ratio of 3:1.5:1.5. 50 Silicon carbide particles of 20 μm, D 50 Silicon carbide particles and whiskers are 1 μm in size.

[0048] The preparation method of the composite thermally conductive filler is as follows: The particle size D is... 50 Silicon carbide particles of 20 μm, particle size D 50 A mixed filler was obtained by mixing 1μm silicon carbide particles and silicon carbide whiskers. Silane coupling agent KH560 was added to the mixed filler at a mass ratio of 1:20, and the mixture was stirred until homogeneous to obtain a composite thermally conductive filler.

[0049] The polyurethane acrylate is a trifunctional aliphatic polyester PUA from Guangdong Boxin New Material Technology Co., Ltd., model B-369, with a solid content ≥97% wt% and a viscosity of 5000 CPS / 60℃.

[0050] The fire extinguishing capsules were purchased from Langfang Kamft New Materials Co., Ltd. as fire extinguishing and protection microcapsules.

[0051] S2, Curing into a film

[0052] The curing process is the same as in Example 1.

[0053] Comparative Example 1

[0054] The difference between this comparative example and Example 1 is that the composite thermally conductive filler does not include D. 50 The silicon carbide particles are 15 μm in size, and the rest is the same as in Example 1.

[0055] Comparative Example 2

[0056] The difference between this comparative example and Example 1 is that the composite thermally conductive filler does not include D. 50 The silicon carbide particles are 1 μm in size, and the rest is the same as in Example 1.

[0057] Comparative Example 3

[0058] The difference between this comparative example and Example 1 is that the composite thermally conductive filler does not include silicon carbide whiskers; otherwise, it is the same as Example 1.

[0059] II. Testing Methods

[0060] The thermal conductivity, film thickness, and flame resistance of the heat-conducting fire extinguishing membranes prepared in Examples 1-3 and Comparative Examples 1-3 were tested using the following methods.

[0061] 1. Thermal conductivity: The thermal conductivity of the thermally conductive fire extinguishing membrane was determined by temperature wave analysis according to GB / T42919.3-2023.

[0062] 2. Flame resistance of fire extinguishing membrane

[0063] According to GB / T 15903-1995 Test Method for Flame Retardancy of Pressure Sensitive Adhesive Tape, the suspension method was used for testing. Before sampling, the outermost 5 rolls of the fire extinguishing film were removed, and then it was evenly unrolled to cut 6 samples with a length of 300 mm and a width of 25 mm. Marking lines were made on the back of each sample at 50 mm and 150 mm from its top. The prepared samples had no defects such as deformation that was difficult to recover or surface contamination. One end of the prepared sample was clamped with a clamp and freely suspended in the test protective cover; the bottom edge of the ignition material was overlapped and bonded to the bottom end of the sample closest to the 50 mm mark by about 2 mm; the ignition material was ignited with a flame of about 20 mm in length at the apex of the triangle, and the fire source was immediately removed and the protective cover door was closed. For samples that self-extinguished after burning, the distance from the marking line to the nearest point on the charred edge of the sample was measured with a steel ruler. The average burning length (AEB) was calculated according to formula (1), and the flame retardancy rating was determined according to Table 1.

[0064] (1),

[0065] Where: L-150mm is the distance from the mark line to the nearest point on the charred edge of the sample, in mm;

[0066] N - The number of samples tested.

[0067] Table 1 Flame Retardancy Rating Table

[0068] Flame resistance rating Average burning length (AEB) Explanation Class 0 AEB = 0 Non-flammable (ignition material burns out, sample does not burn) Class 1 0 < AEB < 50 Self-extinguishing, good flame resistance Class 2 50 < AEB < 150 Flammable, poor flame resistance Class 3 AEB > 150 Flammable

[0069] 3. Thickness of the fire extinguishing membrane

[0070] The test was conducted according to GB / T 7125-2014, Test Method for Thickness of Adhesive Tape. Five rolls of fire extinguishing film were taken, and six layers were removed from each roll. A 10cm long, wrinkle-free sample was then cut. Five samples were prepared. The sample was placed between the upper and lower planes of the measuring head of the measuring instrument. During the test, the upper measuring head was slowly lowered until it covered the surface of the fire extinguishing film. One second after lowering the upper measuring head, the reading of the indicator was recorded in mm as the total thickness. Three points were measured at different locations for each sample. A mark was made on the upper and lower PET film at the measured location. The upper and lower PET films were then removed, and the thickness at the marked location was measured using the above steps, recorded as the upper PET film thickness and the lower PET film thickness, respectively. The difference between the total thickness and the upper and lower PET film thicknesses at each location was calculated. The arithmetic mean of the three differences was the thickness value of the sample.

[0071] III. Test Results

[0072] The thermal conductivity, film thickness, and flame resistance test results of the thermally conductive fire extinguishing membranes prepared in Examples 1-3 and Comparative Examples 1-3 are shown in Table 2.

[0073] Table 2 Performance Test Results

[0074] No. Thermal conductivity (W / m·K) Film thickness (mm) Flame resistance rating Example 1 5.2 5.502 0 Example 2 6.0 5.228 0 Example 3 6.3 5.344 1 Comparative Example 1 1.2 5.389 1 Comparative Example 2 1.5 5.276 1 Comparative Example 3 2.0 5.632 1

[0075] The thermal conductivity of the film prepared in Example 1 was 5.2 W / m·K, while the thermal conductivity of the films prepared in Comparative Examples 1-3 was 1.2-2.0 W / m·K, indicating a lack of D. 50 Silicon carbide particles of 15μm, D 50 Composite thermally conductive fillers prepared from either 1μm silicon carbide particles or silicon carbide whiskers cannot achieve optimal thermal conductivity in the thermally conductive fire extinguishing membrane. Therefore, improving the thermal conductivity of the thermally conductive fire extinguishing membrane is crucial. 50 Silicon carbide particles of 15μm, D 50 Silicon carbide particles of 1 μm and silicon carbide whiskers exhibit a synergistic effect. Because the point contact area between silicon carbide whiskers and silicon carbide particles is insufficient, the interfacial phonon projection rate between them is low. Simultaneously, the addition of D... 50 SiC particles of 15-20 μm, D 50 SiC particles of 1-3 μm are dispersed within silicon carbide whiskers, increasing the point contact area between the silicon carbide particles and whiskers. This, in turn, increases the phonon projection rate at the interface between the silicon carbide whiskers and particles, and reduces the interfacial thermal resistance. Therefore, this invention improves the thermal conductivity of the prepared thermally conductive fire extinguishing membrane through the synergistic effect of SiC particles of varying sizes and silicon carbide whiskers. Furthermore, Examples 1-3 demonstrate that the prepared membrane exhibits excellent flame-retardant properties.

[0076] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0077] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

[0078] The present invention has been illustrated with the above embodiments to describe the detailed process flow of the present invention. However, the present invention is not limited to the above detailed process flow, that is, it does not mean that the present invention must rely on the above detailed process flow to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions of the raw materials of the product of the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A method of making a heat-conducting fire extinguishing film, characterized by, The method comprises the following steps: S1, preparing a composite heat-conductive filler Silicon carbide particles having a particle size D 50 of 15-20 μm, silicon carbide particles having a particle size D 50 of 1-3 μm, and silicon carbide whiskers are mixed to obtain a mixed filler, a silane coupling agent is added to the mixed filler in a mass ratio of 1:10-20, and stirring is performed to obtain a composite heat-conducting filler. S2, preparing a heat-conductive fire-extinguishing film The crosslinking agent, the dispersing agent, the photoinitiator, the fire-extinguishing material and the composite heat-conductive filler are sequentially added into the resin, mixed uniformly to prepare a heat-conductive fire-extinguishing slurry, and the heat-conductive fire-extinguishing slurry is calendered and cured to obtain the heat-conductive fire-extinguishing film. The particle size D 50 Silicon carbide particles having a particle size D 50 The volume ratio of silicon carbide particles having a particle size D 1-3 μm, silicon carbide whiskers is 3:0.5-1.5:0.5-1.

5.

2. The production method according to claim 1, wherein The diameter of the silicon carbide whisker is 0.2-1 μm, and the length is 6-30 μm.

3. The production method according to claim 2, wherein The diameter of the silicon carbide whisker is 0.5 μm, and the length is 15 μm.

4. The production method according to claim 1, wherein The particle size D 50 Silicon carbide particles having a particle size D 50 Silicon carbide particles having a particle size D 1-3 μm, and a volume ratio of silicon carbide particles, silicon carbide whiskers, and silicon carbide grains of 3:1:

1.

5. The production method according to claim 1, wherein The resin comprises isooctyl acrylate, isobornyl acrylate and polyurethane acrylate, and the mass ratio of the isooctyl acrylate, the isobornyl acrylate and the polyurethane acrylate is 60-75:10-35:70-160.

6. A heat-conducting fire extinguishing film, characterized by The heat-conductive fire-extinguishing film is prepared by the preparation method of claim 1.

7. Use of the heat-conducting fire extinguishing film prepared by the preparation method of any one of claims 2-5 or the heat-conducting fire extinguishing film of claim 6 for preventing the spontaneous combustion of an energy storage device. The heat-conductive fire-extinguishing film is coated on the outer circumferential surface of the energy storage device.