Fire extinguishing film as well as preparation method and application thereof

Abstract

The invention provides a fire-extinguishing film and a preparation method and application thereof, and relates to the technical field of fire-extinguishing material preparation. The preparation method of the fire extinguishing film comprises the following steps: providing an acrylic monomer and polyurethane acrylate, uniformly mixing the acrylic monomer and the polyurethane acrylate, adding a cross-linking agent and an initiator to obtain a mixed base material, adding a fire extinguishing capsule into the mixed base material, uniformly mixing to obtain a fire extinguishing composition, and calendering and curing the fire extinguishing composition to obtain the fire extinguishing film. The weight part ratio of the acrylic monomer to the polyurethane acrylate is 100: (50-300); the weight part ratio of the cross-linking agent to the acrylic monomer is (1-10): 100. The fire extinguishing capsule with the fire extinguishing membrane prepared by the preparation method is relatively high in use sensitivity and fire extinguishing efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of fire extinguishing material preparation, and particularly relates to a fire extinguishing film, a preparation method thereof and an application thereof. Background Art

[0002] In recent years, with the development of the electrical and electronic industries, the number of energy storage devices such as secondary batteries has been increasing continuously. People are also actively researching and developing battery packs that improve capacity and output power by connecting multiple secondary batteries in parallel or series. However, due to overcharging and overcurrent, high-performance and high-capacity battery packs have the risks of fire and explosion. Therefore, measures are being taken to prevent battery fires or extinguish fires as early as possible when a battery catches fire.

[0003] Water and dry ice are commonly used fire extinguishing media, and fire extinguishing capsules are emerging fire extinguishing media in recent years. The fire extinguishing capsule includes a shell and a fire extinguishing substance inside the shell. The shell is a polymer resin, and the fire extinguishing substance inside the shell is generally a fluorine-containing substance that is liquid at room temperature, has a low heat of vaporization, and a high vapor pressure. The fire extinguishing substance inside the shell absorbs heat when heated and vaporizes to form a fire extinguishing gas to isolate oxygen, thereby achieving the fire extinguishing effect.

[0004] In the prior art, for convenient use, the fire extinguishing capsules are dispersed in a polymer to prepare a fire extinguishing film. This not only forms a protective film on the surface of the fire extinguishing capsule, but also can conveniently apply the fire extinguishing capsule to various fire prevention and extinguishing scenarios. However, the polymer has a self-healing function under certain conditions, which hinders the triggering of the fire extinguishing capsule to generate a fire extinguishing gas to a certain extent. On the other hand, the polymer has a barrier function for the fire extinguishing gas, which hinders the flow of the fire extinguishing gas to a certain extent, thereby reducing the sensitivity and fire extinguishing efficiency of the fire extinguishing capsule. Summary of the Invention

[0005] Aiming at the deficiencies of the prior art, the present invention provides a fire extinguishing film, a preparation method thereof and an application thereof, and solves the problem that the polymer in the existing fire extinguishing film reduces the sensitivity and fire extinguishing efficiency of the fire extinguishing capsule.

[0006] To achieve the above purposes, the present invention is realized through the following technical solutions:

[0007] On the one hand, the present invention provides a preparation method of a fire extinguishing film, including the following steps:

[0008] Providing an acrylic monomer and a polyurethane acrylate, mixing them evenly and then adding a crosslinking agent and an initiator to obtain a mixed substrate, adding a fire extinguishing capsule to the mixed substrate, mixing evenly to prepare a fire extinguishing composition, and calendering and curing the fire extinguishing composition to obtain a fire extinguishing film;

[0009] The weight ratio of the acrylic monomer to the polyurethane acrylate is 100:50 - 300;

[0010] The weight ratio of the crosslinking agent to the acrylic monomer is 1-10:100.

[0011] The preparation method of the above fire extinguishing film uses acrylic monomers, two-component polyurethane acrylate materials and crosslinking agents to prepare a mixed substrate. Among them, the weight ratio of acrylic monomers to polyurethane acrylate is 100:50-300, and the weight ratio of crosslinking agents to acrylic monomers is 1-10:100. After the mixed substrate is cured, the fire extinguishing hindrance to the fire extinguishing capsule under normal conditions is small, the sensitivity and fire extinguishing efficiency of the fire extinguishing capsule are high, and the utilization rate of the fire extinguishing capsule is improved by the prepared fire extinguishing film.

[0012] Preferably, other additives are further included, and the other additives include at least one of a coupling agent, a surfactant, a dye, a pigment, and an antioxidant.

[0013] The coupling agent promotes the crosslinking of acrylic monomers to form a three-dimensional network, resists the damage to the fire extinguishing film caused by sunlight, rain or temperature over time, and improves the durability of the fire extinguishing film. The surfactant can be used as a dispersant and an antifoaming agent. As a dispersant, it can prevent the precipitation of the fire extinguishing capsule and reduce the surface tension. As an antifoaming agent, it can inhibit the formation of bubbles. Dyes, pigments, ultraviolet light inhibitors, antioxidants, etc. can be added within the range of maintaining their performance, and the addition amount can vary according to the characteristics of the final product to be targeted.

[0014] Preferably, the initiator is a photoinitiator.

[0015] Select a photoinitiator to cure the fire extinguishing film under light conditions, avoid the heating and curing steps, prevent the triggering of the fire extinguishing capsule due to poor control of the heating temperature during the heating process, and improve the yield of the fire extinguishing film.

[0016] Preferably, the acrylic monomer is selected from at least one of butyl acrylate, butyl methacrylate, n-hexyl acrylate, hexyl methacrylate, n-octyl acrylate, n-octyl methacrylate, isooctyl acrylate, isooctyl methacrylate, 2-hydroxyethyl acrylate, and isobornyl acrylate.

[0017] Preferably, the acrylic monomer includes isooctyl acrylate and isobornyl acrylate, and the weight ratio of isooctyl acrylate to isobornyl acrylate is 1:1-4:1.

[0018] When the weight ratio of isooctyl acrylate to isobornyl acrylate is 1:1-4:1, the flame resistance of the fire extinguishing film is greatly improved, and the flame resistance level is 0-1.

[0019] Preferably, the weight ratio of isooctyl acrylate to isobornyl acrylate is 4:1.

[0020] When the weight ratio of isooctyl acrylate to isobornyl acrylate is 4:1, the flame resistance of the fire extinguishing film is significantly improved, and the flame resistance grade is 0.

[0021] Preferably, the weight ratio of isooctyl acrylate to isobornyl acrylate is 2:1.

[0022] When the weight ratio of isooctyl acrylate to isobornyl acrylate is 2:1, the flame resistance of the fire extinguishing film is significantly improved, and the flame resistance grade is 0.

[0023] Preferably, the weight ratio of the fire extinguishing capsule to the mixed base material is 50%-200%.

[0024] The fire extinguishing film with the weight ratio of the fire extinguishing capsule to the mixed base material being 50%-200% has a flame resistance grade of 0-1.

[0025] Preferably, the fire extinguishing capsule includes a shell and fire extinguishing contents inside the shell. The fire extinguishing contents are selected from NOVEC1230, heptafluorobutyric anhydride, ethyl heptafluorobutyrate, tetradecafluorohexane, and tetrachloro-perfluoro-6-methyl-3,5-dioxoheptane. The volatilization temperature of heptafluorobutyric anhydride, ethyl heptafluorobutyrate, tetradecafluorohexane, and tetrachloro-perfluoro-6-methyl-3,5-dioxoheptane is above 45°C.

[0026] The volatilization temperature of heptafluorobutyric anhydride, ethyl heptafluorobutyrate, tetradecafluorohexane, and tetrachloro-perfluoro-6-methyl-3,5-dioxoheptane being above 45°C improves the yield of the fire extinguishing film.

[0027] In a second aspect, the present invention provides a fire extinguishing film, which is prepared by the preparation method described in the first aspect. The fire extinguishing film includes acrylic monomers, polyurethane acrylate, a crosslinking agent, and a fire extinguishing capsule. The weight ratio of the acrylic monomers to the polyurethane acrylate is 100:50-300, the weight ratio of the crosslinking agent to the acrylic monomers is 1-10:100, and the weight ratio of the fire extinguishing capsule to the mixed base material is 50%-200%.

[0028] The above-mentioned fire extinguishing film includes a two-component material of acrylic monomers and polyurethane acrylate and a crosslinking agent. Among them, the weight ratio of the acrylic monomers to the polyurethane acrylate is 100:50-300, and the weight ratio of the crosslinking agent to the acrylic monomers is 1-10:100. The fire extinguishing film has less hindrance to the fire extinguishing of the fire extinguishing capsule under normal circumstances, and the fire extinguishing capsule has higher sensitivity and fire extinguishing efficiency, improving the utilization rate of the fire extinguishing capsule.

[0029] In a third aspect, the present invention provides an application of the fire extinguishing film prepared by the preparation method described in the first aspect or the fire extinguishing film described in the second aspect in preventing a energy storage device from catching fire, wherein the fire extinguishing film is coated on the outer peripheral surface of the energy storage device. Coating the fire extinguishing film on the outer peripheral surface of the energy storage device can achieve fire prevention and extinguishing, without pipelines, convenient construction operation, intelligent response, active fire extinguishing, and no space occupation.

[0030] Beneficial effects

[0031] The present invention provides a fire extinguishing film, a preparation method thereof, and an application thereof. Compared with the prior art, the following beneficial effects are achieved:

[0032] 1. In the solution of the present application, under the synergistic action of acrylic monomers and polyurethane acrylate, the utilization efficiency of the fire extinguishing capsules is improved, and the flame resistance of the fire extinguishing film with the weight ratio of the fire extinguishing capsules to the mixed base material being 50%-200% is 0-1 level.

[0033] 2. The ratio of isooctyl acrylate to isobornyl acrylate has a significant influence on the flame resistance of the fire extinguishing film. When the weight ratio of isooctyl acrylate to isobornyl acrylate is 1:1-4:1, the flame resistance of the fire extinguishing film is greatly improved. When the weight ratio of isooctyl acrylate to isobornyl acrylate is 4:1 or 2:1, the flame resistance of the fire extinguishing film is significantly improved.

[0034] 3. When the weight ratio of acrylic monomers to polyurethane acrylate is 100:50-300, the prepared fire extinguishing film has excellent flame resistance. When the weight ratio of the crosslinking agent to acrylic monomers is 1-10:100, the prepared fire extinguishing film has excellent flame resistance. Brief description of the drawings

[0035] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention, and those of ordinary skill in the art can obtain other drawings based on these drawings without creative efforts.

[0036] Figure 1 Schematic diagram of the preparation method process of the fire extinguishing film in Example 1.

[0037] Figure 2 Physical photo of the fire extinguishing film in Example 1;

[0038] Figure 3 Schematic diagram of the curing process of the fire extinguishing film in Example 1. Detailed implementation manners

[0039] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described. Apparently, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0040] By providing a fire extinguishing film, a preparation method thereof, and an application thereof, the embodiments of the present application solve the problem that the fire extinguishing film reduces the sensitivity and fire extinguishing efficiency of the fire extinguishing capsules, and achieve a fire resistance rating of 0-1 for the fire extinguishing film with the weight ratio of the fire extinguishing capsules in the mixed base material being 50%-200%.

[0041] The overall idea of the technical solutions in the embodiments of the present application to solve the above technical problems is as follows:

[0042]

Fire Extinguishing Film

[0043] The present invention provides a fire extinguishing film, which comprises acrylic monomers, polyurethane acrylate, a crosslinking agent, and fire extinguishing capsules. The weight ratio of the acrylic monomers to the polyurethane acrylate is 100:50-300, the weight ratio of the crosslinking agent to the acrylic monomers is 1-10:100, and the fire extinguishing capsules account for 50%-200% of the weight of the mixed base material.

[0044] The above fire extinguishing film comprises a two-component material of acrylic monomers and polyurethane acrylate, and a crosslinking agent. Among them, the weight ratio of the acrylic monomers to the polyurethane acrylate is 100:50-300, the weight ratio of the crosslinking agent to the acrylic monomers is 1-10:100. The fire extinguishing film has less obstruction to the fire extinguishing of the fire extinguishing capsules under normal circumstances, the fire extinguishing capsules have higher sensitivity and fire extinguishing efficiency, and the utilization rate of the fire extinguishing capsules is improved.

[0045] In this article, the term "acrylic monomers" refers to unsaturated carboxylic acids, including but not limited to butyl acrylate, butyl methacrylate, n-hexyl acrylate, hexyl methacrylate, n-octyl acrylate, n-octyl methacrylate, isooctyl acrylate, isooctyl methacrylate, 2-hydroxyethyl acrylate, and isobornyl acrylate.

[0046] In this article, the term "polyurethane acrylate" refers to a substance containing an acrylic functional group and a urethane bond in the molecule. Exemplarily, the functionality is 1-4, and the viscosity is 5000 CPS for the polyurethane acrylate system at 60°C.

[0047] In this article, the term "fire extinguishing capsules" refers to a fire extinguishing material formed by encapsulating a fire extinguishing agent in a polymer shell.

[0048] In some embodiments, the capsule diameter of the fire extinguishing capsule is 30 μm - 500 μm, such as 30 μm, 50 μm, 70 μm, 90 μm, 110 μm, 150 μm, 200 μm, 250 μm, 300 μm, 350 μm, 400 μm, 450 μm, 500 μm or any value therebetween.

[0049] In some embodiments, the weight ratio of the acrylic monomer to the polyurethane acrylate is 100:50, 100:60, 100:70, 100:80, 100:90, 100:100, 100:150, 100:200, 100:250, 100:300 or any value therebetween.

[0050] In some embodiments, the crosslinking agent is selected from any one of divinylbenzene, diisocyanate, N,N-methylenebisacrylamide, and aziridine crosslinking agent.

[0051] In some embodiments, the weight ratio of the crosslinking agent to the acrylic monomer is 1:100, 2:100, 3:100, 4:100, 5:100, 6:100, 7:100, 8:100, 9:100, 10:100 or any value therebetween.

[0052] In some embodiments, the weight ratio of the fire extinguishing capsule to the mixed substrate is 50%, 60%, 70%, 80%, 90%, 100%, 110%, 120%, 130%, 140%, 150%, 160%, 170%, 180%, 190%, 200% or any value therebetween.

[0053] In some embodiments, the film thickness of the fire extinguishing film is 0.25 mm to 6 mm, such as 0.25 mm, 1.00 mm, 2.00 mm, 3.00 mm, 4.00 mm, 5.00 mm, 6.00 mm or any value therebetween.

[0054]

Preparation Method of Fire Extinguishing Film

[0055] The present invention provides a preparation method of a fire extinguishing film, comprising the following steps:

[0056] Providing an acrylic monomer and a polyurethane acrylate, mixing them evenly and then adding a crosslinking agent and an initiator to obtain a mixed substrate, adding a fire extinguishing capsule to the mixed substrate, mixing evenly to prepare a fire extinguishing composition, and calendering and curing the fire extinguishing composition to obtain the fire extinguishing film;

[0057] The weight ratio of the acrylic monomer to the polyurethane acrylate is 100:50 - 300;

[0058] The weight ratio of the crosslinking agent to the acrylic monomer is 1-10:100.

[0059] In some embodiments, the capsule diameter of the fire extinguishing capsule is 30μm-500μm, such as 30μm, 50μm, 70μm, 90μm, 110μm, 150μm, 200μm, 250μm, 300μm, 350μm, 400μm, 450μm, 500μm or any value therebetween.

[0060] In some embodiments, the weight ratio of the acrylic monomer to the polyurethane acrylate is 100:50, 100:60, 100:70, 100:80, 100:90, 100:100, 100:150, 100:200, 100:250, 100:300 or any value therebetween.

[0061] In some embodiments, the weight ratio of the crosslinking agent to the acrylic monomer is 1:100, 2:100, 3:100, 4:100, 5:100, 6:100, 7:100, 8:100, 9:100, 10:100 or any value therebetween.

[0062] In some embodiments, the crosslinking agent can be selected from ethylene glycol diacrylate, ethylene glycol diacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, propylene glycol diacrylate, dipropylene glycol diacrylate, tripropylene glycol diacrylate, di-functional acrylate-based crosslinking agent, triacrylate crosslinking agent, aziridine-based crosslinking agent, epoxy-based crosslinking agent, etc.

[0063] The preparation method of the above-mentioned fire extinguishing film uses a two-component material of acrylic monomer and polyurethane acrylate and a crosslinking agent to prepare a mixed substrate. Among them, the weight ratio of the acrylic monomer to the polyurethane acrylate is 100:50-300, and the weight ratio of the crosslinking agent to the acrylic monomer is 1-10:100. After the mixed substrate is cured, the fire extinguishing hindrance to the fire extinguishing capsule under normal conditions is small, the sensitivity and fire extinguishing efficiency of the fire extinguishing capsule are high, and the utilization rate of the fire extinguishing capsule is improved in the prepared fire extinguishing film.

[0064] Preferably, other additives are further included, and the other additives include at least one of a coupling agent, a surfactant, a dye, a pigment, and an antioxidant.

[0065] Coupling agents promote the cross-linking of acrylic monomers to form a three-dimensional network, resisting damage to the fire extinguishing film caused by sunlight, rain, or temperature over time, and improving the durability of the fire extinguishing film. In some embodiments, the coupling agent is selected from any one of 3-methacryloxypropyltrimethoxysilane, vinyltriethoxysilane, and γ-aminopropyltriethoxysilane. In some embodiments, the weight ratio of the coupling agent to the acrylic monomer is 0.1-2:100. Surfactants can be used as dispersants and defoamers. As a dispersant, it can prevent the precipitation of fire extinguishing capsules and reduce the surface tension. As a defoamer, it can inhibit the formation of bubbles. In some embodiments, the weight ratio of the surfactant to the acrylic monomer is 0.05-3:100. Dyes, pigments, UV agents, antioxidants, etc. can be added within the range of maintaining their properties, and the addition amount can vary according to the characteristics of the final product to be targeted. In some embodiments, the dispersant is selected from any one of polyvinyl alcohol, vinyl alcohol copolymer, styrene-maleic anhydride copolymer, vinyl acetate-maleic anhydride copolymer, polyacrylic acid and its salts, polyvinylpyrrolidone, and sulfonated polystyrene.

[0066] Preferably, the initiator is a photoinitiator. In some embodiments, the weight ratio of the initiator to the acrylic monomer is 0.1-5:100. If the weight ratio of the initiator to the acrylic monomer is less than 0.1:100, unreacted monomers may occur; if the weight ratio of the initiator to the acrylic monomer is greater than 5:100, it may reduce the polymer molecular weight and cause problems such as high initial tack.

[0067] In some embodiments, the photoinitiator can be a substance that absorbs energy at a certain wavelength in the ultraviolet region (250-420 nm) and generates free radicals, cations, etc. For example, it can be benzoin ethyl ether, benzoin isosafrole ether, anisidine ethyl ether, benzoin, benzyl ketal, etc.

[0068] In some embodiments, a UV lamp is used for the curing operation, and the power of the UV lamp is 30 W to 150 W, for example, 30 W, 50 W, 80 W, 90 W, 110 W, 130 W, 150 W, or any value therebetween.

[0069] Select a photoinitiator and cure to prepare the fire extinguishing film under light conditions, avoiding the heating curing step, preventing the triggering of the fire extinguishing capsules due to poor control of the heating temperature during the heating process, and improving the yield of the fire extinguishing film.

[0070] In some embodiments, the acrylic monomer is selected from at least one of butyl acrylate, butyl methacrylate, n-hexyl acrylate, hexyl methacrylate, n-octyl acrylate, n-octyl methacrylate, isooctyl acrylate, isooctyl methacrylate, 2-hydroxyethyl acrylate, and isobornyl acrylate.

[0071] In some embodiments, the acrylic monomer includes isooctyl acrylate and isobornyl acrylate, and the weight ratio of isooctyl acrylate to isobornyl acrylate is 1:1 - 4:1, for example, 1:1, 1.5:1, 2:1, 2.5:1, 3:1, 4:1, or any value therebetween, which greatly improves the flame resistance of the fire extinguishing film, and the flame resistance level is 0 - 1. The flame resistance level can be tested by methods and equipment known in the art. As an example: Test the flame resistance level according to GB / T 15903 - 1995, and the instrument model is the touch screen controlled textile vertical burning tester of Dongguan Tuojin Instrument Co., Ltd.

[0072] In some embodiments, the weight ratio of the fire extinguishing capsule to the mixed substrate is 50% - 200%, for example, 50%, 60%, 70%, 80%, 90%, 100%, 110%, 120%, 130%, 140%, 150%, 160%, 170%, 180%, 190%, 200%, or any value therebetween, and the flame resistance level of the fire extinguishing film is 0 - 1.

[0073] In some embodiments, during the film curing stage, the fire extinguishing composition is delivered onto a carrier film, which includes a lower carrier film for carrying the fire extinguishing composition and an upper carrier film covering the upper surface of the fire extinguishing composition, and at least one of the lower carrier film and the upper carrier film is a PET film.

[0074]

Application of the fire extinguishing film

[0075] The present invention provides an application of the described fire extinguishing film in preventing the energy storage device from catching fire, and the fire extinguishing film is coated on the outer peripheral surface of the energy storage device. Coating the fire extinguishing film on the outer peripheral surface of the energy storage device can achieve fire prevention and extinguishing, without pipelines, convenient construction operation, intelligent response, active fire extinguishing, and does not occupy space.

[0076] In this text, the term "energy storage device" refers to a device or system that can store energy and release it when needed, including but not limited to mechanical energy storage devices, chemical energy storage devices, electromagnetic energy storage devices, or thermal energy storage devices. Among them, mechanical energy storage devices include pumped-storage devices and compressed air energy storage devices, which store energy by using gravity or gas compression; chemical energy storage devices exist in the form of batteries, such as lithium-ion batteries, lead-acid batteries, and fuel cells, which store and release electrical energy through chemical reactions; electromagnetic energy storage devices are represented by supercapacitors, which can charge and discharge quickly and are suitable for occasions with instantaneous energy requirements; thermal energy storage devices refer to using the temperature change of substances for energy storage, such as salt melting energy storage devices, etc.

[0077] In this text, the term "coating" means that the fire extinguishing film wraps and covers the outer peripheral surface of the energy storage device. The fire extinguishing film can be fixedly connected to the outer peripheral surface of the energy storage device or merely cover its outer peripheral surface. The fixed connection can be achieved by methods known in the art, including but not limited to gluing, welding, mechanical fixing, etc.

[0078] To better understand the above technical solutions, the above technical solutions will be described in detail below in conjunction with the accompanying drawings of the specification and specific embodiments.

[0079] I. Preparation Method

[0080] Example 1

[0081] This example provides a preparation method of a fire extinguishing film, as Figure 1 shown, including the following steps:

[0082] S1. Prepare the fire extinguishing composition

[0083] Weigh 100 parts by weight of acrylic monomers, 150 parts by weight of polyurethane acrylate and mix them evenly. Then add 5 parts by weight of the cross-linking agent ethylene glycol diacrylate, 5 parts by weight of other additives and mix them evenly. Then add 2.5 parts by weight of the photoinitiator benzoin ethyl ether to obtain a mixed base material. Add fire extinguishing capsules accounting for 100% of the weight of the mixed base material into the mixed base material and stir to make the fire extinguishing capsules evenly dispersed in the mixed base material to prepare the fire extinguishing composition.

[0084] Among them, the fire extinguishing capsules used in this example are the fire extinguishing agent NOVEC1230 of 3M Company in the United States. The acrylic monomers include isooctyl acrylate and isobornyl acrylate, and the weight ratio of the two is 2:1. The other additives are 2 parts by weight of the coupling agent methacryloxypropyltrimethoxysilane and 3 parts by weight of the dispersant polyvinylpyrrolidone.

[0085] S2. Cure into a film

[0086] As Figure 3As shown, the fire extinguishing composition is poured into the glue tank, and the first PET carrier film 4 and the second PET carrier film 6 are respectively installed on the first transfer roller 3 and the second transfer roller 5 of the calender. The fire extinguishing composition in the glue tank is transported to the second PET carrier film 6 through the coating head 1 and the glue baffle 2. At the same time, the first transfer roller 3 and the second transfer roller 5 of the calender are started, so that the first PET carrier film 4, the second PET carrier film 6 and the fire extinguishing composition on the second PET carrier film 6 pass through the first transfer roller 3 and the second transfer roller 5 of the calender together. Under the cooperation of the first transfer roller 3 and the second transfer roller 5, the first PET carrier film 4, the second PET carrier film 6 and the fire extinguishing composition therebetween are calendered to control the thickness of the fire extinguishing composition; the first PET carrier film 4, the second PET carrier film 6 and the fire extinguishing composition therebetween after the calendering process enter the ultraviolet lamp box 7 together. The power of the ultraviolet lamp is 80W. Under the action of ultraviolet light, the fire extinguishing composition is cured to form a fire extinguishing film 8, and it is wound by the winding roller 9.

[0087] During the processing of the fire extinguishing film, calendering and curing can be carried out synchronously, which greatly improves the production efficiency of the fire extinguishing film and is conducive to large-scale batch production. The physical picture of the fire extinguishing film is as Figure 2 shown.

[0088] Examples 2-7

[0089] In Examples 2-7, the acrylic monomers include isooctyl acrylate and isobornyl acrylate. The total weight parts of isooctyl acrylate and isobornyl acrylate are 100, and the dosage of polyurethane acrylate is 150 weight parts. The difference from Example 1 is that the weight part ratio of isooctyl acrylate and isobornyl acrylate is different, as shown in Table 1 for details, and the others are the same as Example 1.

[0090] Table 1 Preparation parameters of fire extinguishing films in Examples 1-7 Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Weight ratio of isooctyl acrylate and isobornyl acrylate 2:1 4:1 1:1 1:2 1:3 1:4 1:5

[0091] Examples 8-14

[0092] In Examples 8-14, the acrylic monomers include isooctyl acrylate and isobornyl acrylate, and the weight part ratio of isooctyl acrylate and isobornyl acrylate is 2:1. The difference from Example 1 is that the weight part ratio of the acrylic monomers and polyurethane acrylate is different, as shown in Table 2 for details, and the others are the same as Example 1.

[0093] Examples 15-20

[0094] In Examples 15-20, the acrylic monomers include isooctyl acrylate and isobornyl acrylate, and the weight part ratio of isooctyl acrylate and isobornyl acrylate is 2:1. The difference from Example 1 is that the dosage of the crosslinking agent is different, and the specific dosage is shown in Table 2, and the others are the same as Example 1.

[0095] Table 2 Preparation Parameters of Fire - extinguishing Films for Examples 8 - 20 Weight parts of acrylic monomers Weight parts of polyurethane acrylate Weight parts of crosslinking agent Example 8 100 10 5 Example 9 100 50 5 Example 10 100 100 5 Example 11 100 200 5 Example 12 100 250 5 Example 13 100 300 5 Example 14 100 350 5 Example 15 100 150 0 Example 16 100 150 1 Example 17 100 150 3 Example 18 100 150 7 Example 19 100 150 10 Example 20 100 150 12

[0096] Example 21

[0097] The difference between this example and Example 1 is that the weight ratio of the fire - extinguishing capsules in the mixed base material is 50%, and the others are the same as in Example 1.

[0098] Comparative Examples 1 - 8

[0099] In Comparative Example 1, the components of the main resin of the fire - extinguishing composition were adjusted. The difference compared with Example 1 is that it does not include acrylic monomers, the weight portion of polyurethane acrylate is 250, and the others are the same as in Example 1. The specific parameters are shown in Table 3.

[0100] In Comparative Example 2, the components of the main resin of the fire - extinguishing composition were adjusted. The difference compared with Example 1 is that it does not include polyurethane acrylate, the weight portion of acrylic monomers is 250, and the others are the same as in Example 1. The specific parameters are shown in Table 3.

[0101] In Comparative Examples 3 - 5, the weight ratio of the fire - extinguishing capsules in the mixed base material was adjusted, and the others are the same as in Comparative Example 1. The specific parameters are shown in Table 3.

[0102] In Comparative Examples 6 - 8, the weight ratio of the fire - extinguishing capsules in the mixed base material was adjusted, and the others are the same as in Comparative Example 2. The specific parameters are shown in Table 3.

[0103] Table 3 Parameters for Preparing Fire - extinguishing Films in Comparative Examples Weight parts of acrylic monomers Weight ratio of isooctyl acrylate and isobornyl acrylate Weight parts of polyurethane acrylate Weight ratio of fire extinguishing capsules to mixed base materials Comparative Example 1 0 -- 250 100% Comparative Example 2 250 2:1 0 100% Comparative Example 3 0 -- 250 140% Comparative Example 4 0 -- 250 160% Comparative Example 5 0 -- 250 220% Comparative Example 6 250 2:1 0 140% Comparative Example 7 250 2:1 0 160% Comparative Example 8 250 2:1 0 220%

[0104] II. Test Methods

[0105] 1. Flame Resistance of Fire - extinguishing Films

[0106] The test was carried out according to the hanging method in the test method for flame resistance of pressure - sensitive adhesive tapes GB / T 15903 - 1995. Before sampling, the outermost 5 turns of the roll - shaped fire - extinguishing film were removed in advance, and then it was evenly unwound. Six specimens with a length of 300 mm and a width of 25 mm were cut. On the back of each specimen, marking lines were made at 50 mm and 150 mm from its top end respectively. The prepared specimens had no defects such as irreversible deformation and surface contamination. One end of the prepared specimen was clamped with a fixture and freely suspended in the test protective cover; the bottom edge of the ignition material was overlapped and adhered to the lower end of the specimen closest to the 50 - mm mark by about 2 mm; after igniting the triangular top angle of the ignition material with a flame of about 20 mm in length, the ignition source was immediately removed, and the protective cover door was closed. For the specimens that self - extinguished after combustion, the distance from the marking line to the nearest point on the charred edge of the specimen was measured with a steel straight ruler. The average burning length (AEB) was calculated according to formula (1), and then the flame - resistance grade was determined according to Table 4.

[0107] (1),

[0108] where: L is the distance from the marking line at 150 mm to the nearest point on the charred edge of the specimen, in mm;

[0109] N is the number of specimens tested.

[0110] Table 4 Flame resistance rating table Flame resistance level Average combustion length (AEB) Description Grade 0 AEB = 0 Non-combustible (the sample does not burn after the ignition material burns out) Grade 1 0 < AEB ≤ 50 Self-extinguishing, with good flame resistance Grade 2 50 < AEB < 150 Combustible, with poor flame resistance Grade 3 AEB ≥ 150 Combustible

[0111] 2. Thickness of the fire extinguishing film

[0112] Test according to the test method for the thickness of adhesive tapes in GB / T 7125-2014. Take 5 rolls of fire extinguishing film to be tested. Remove six layers from each roll of fire extinguishing film, and then cut 1 specimen with a length of 10 cm without wrinkles and creases. A total of 5 specimens are taken out. Place the specimen between the upper and lower planes of the measuring head of the measuring instrument. During the test, slowly lower the upper measuring head until it finally covers the surface of the fire extinguishing film. After 1 s of lowering the upper measuring head, record the reading of the indicating gauge, in mm, as the total thickness. Measure three points at different positions for each specimen. Make a mark on the upper and lower PET films at the measured position. Remove the upper and lower PET films, and measure the thickness at the marked positions using the above steps, and record them as the thickness of the upper PET film and the thickness of the lower PET film respectively. Calculate the difference between the total thickness minus the thicknesses of the upper and lower PET films at each position respectively. The arithmetic mean of the three differences is the thickness value of the specimen.

[0113] III. Test results

[0114] The test results of the fire extinguishing film performance of the above-mentioned examples and comparative examples are shown in Table 5.

[0115] Table 5 Test results of the fire extinguishing film performance of examples and comparative examples Serial number Film thickness / mm Flame resistance level Example 1 5.202 0 Example 2 5.208 0 Example 3 5.204 1 Example 4 5.209 3 Example 5 5.204 3 Example 6 5.205 3 Example 7 5.204 3 Example 8 5.208 3 Example 9 5.205 0 Example 10 5.207 0 Example 11 5.203 0 Example 12 5.208 1 Example 13 5.205 1 Example 14 5.209 3 Example 15 5.201 3 Example 16 5.205 1 Example 17 5.208 0 Example 18 5.204 0 Example 19 5.206 1 Example 20 5.208 2 Example 21 5.199 0 Comparative Example 1 5.301 3 Comparative Example 2 5.206 3 Comparative Example 3 5.402 2 Comparative Example 4 5.179 2 Comparative Example 5 5.205 0 Comparative Example 6 5.199 2 Comparative Example 7 5.204 2 Comparative Example 8 5.189 0

[0116] As can be seen from Table 5 by comparing Example 1 with Comparative Examples 1 and 2, compared with using only a single acrylic monomer or polyurethane acrylate, the fire-extinguishing film prepared from the hybrid base material prepared by combining acrylic monomers and polyurethane acrylate in a two-component material with other components and dosages in this application has better flame resistance and can reach Class 0 flame retardancy. And it can be known from Example 1 that when the fire-extinguishing capsules account for 100% of the weight of the hybrid base material, the prepared fire-extinguishing film can reach Class 0 flame retardancy. While it can be known from Comparative Examples 3-8 that when using only polyurethane acrylate to prepare the fire-extinguishing film or using only acrylic monomers to prepare the fire-extinguishing film, the fire-extinguishing capsules need to account for 220% of the weight of the hybrid base material to reach Class 0 flame retardancy. It can be seen that under the synergistic effect of acrylic monomers and polyurethane acrylate in the solution of this application, the curing of the hybrid base material has less hindrance to the fire extinguishing of the fire-extinguishing capsules under normal circumstances, the sensitivity and fire extinguishing efficiency of the fire-extinguishing capsules are higher, and the prepared fire-extinguishing film can reach Class 0 flame retardancy when the fire-extinguishing capsules account for 100% of the weight of the hybrid base material. As can be seen from the comparison between Examples 1, 9-13 and Examples 8, 14, when the weight ratio of acrylic monomers to polyurethane acrylate is 100:50-300, the prepared fire-extinguishing film has excellent flame resistance. As can be seen from the comparison between Examples 1-3 and Examples 4-7, the ratio of isooctyl acrylate to isobornyl acrylate has a significant impact on the flame resistance of the fire-extinguishing film. When the weight ratio of isooctyl acrylate to isobornyl acrylate is 1:1-4:1, the flame resistance of the fire-extinguishing film is greatly improved. When the weight ratio of isooctyl acrylate to isobornyl acrylate is 4:1 or 2:1, the flame resistance of the fire-extinguishing film is significantly improved. As can be seen from the comparison between Examples 1, 16-19 and Examples 15, 20, when the weight ratio of the crosslinking agent to the acrylic monomer is 1-10:100, the prepared fire-extinguishing film has excellent flame resistance.

[0117] In summary, compared with the prior art, the following beneficial effects are achieved:

[0118] 1. Under the synergistic effect of acrylic monomers and polyurethane acrylate in the solution of this application, the utilization efficiency of the fire-extinguishing capsules is improved, and the flame resistance of the fire-extinguishing film with the fire-extinguishing capsules accounting for 50%-200% of the weight of the hybrid base material is Class 0-1.

[0119] 2. The ratio of isooctyl acrylate to isobornyl acrylate has a significant impact on the flame resistance of the fire-extinguishing film. When the weight ratio of isooctyl acrylate to isobornyl acrylate is 1:1-4:1, the flame resistance of the fire-extinguishing film is greatly improved. When the weight ratio of isooctyl acrylate to isobornyl acrylate is 4:1 or 2:1, the flame resistance of the fire-extinguishing film is significantly improved.

[0120] 3. When the weight ratio of acrylic monomers to polyurethane acrylate is 100:50-300, the prepared fire-extinguishing film has excellent flame resistance. When the weight ratio of the crosslinking agent to the acrylic monomer is 1-10:100, the prepared fire-extinguishing film has excellent flame resistance.

[0121] It should be noted that in this text, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprise", "include" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements not only includes those elements, but also includes other elements not expressly listed, or also includes elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "comprising an..." does not exclude the presence of additional identical elements in the process, method, article or device comprising said element.

[0122] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements 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.

[0123] The present invention uses the above embodiments to illustrate the detailed process flow of the present invention, but 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 improvement to the present invention, equivalent replacement of the raw materials of the products of the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and the disclosure scope of the present invention.

Claims

1. A method for preparing a fire extinguishing film, characterized in that, It includes the following steps: Providing acrylic monomers and polyurethane acrylate, mixing them evenly and then adding a crosslinking agent and an initiator to obtain a mixed base material, adding fire extinguishing capsules to the mixed base material, mixing evenly to prepare a fire extinguishing composition, and calendering and curing the fire extinguishing composition to obtain a fire extinguishing film; The weight ratio of the acrylic monomers to the polyurethane acrylate is 100:50 - 300; The weight ratio of the crosslinking agent to the acrylic monomers is 1 - 10:

100.

2. The preparation method of the fire extinguishing film according to claim 1, wherein It further includes other additives, and the other additives include at least one of a coupling agent, a surfactant, a dye, a pigment, and an antioxidant.

3. The method for preparing the fire extinguishing film according to claim 1, wherein The initiator is a photoinitiator.

4. The preparation method of the fire extinguishing film according to claim 1, characterized in that, The acrylic monomers are selected from at least one of butyl acrylate, butyl methacrylate, n-hexyl acrylate, hexyl methacrylate, n-octyl acrylate, n-octyl methacrylate, isooctyl acrylate, isooctyl methacrylate, 2-hydroxyethyl acrylate, and isobornyl acrylate.

5. The preparation method of the fire extinguishing film according to claim 4, characterized in that, The acrylic monomers include isooctyl acrylate and isobornyl acrylate, and the weight ratio of isooctyl acrylate to isobornyl acrylate is 1:1 - 4:

1.

6. The method for preparing the fire extinguishing film according to claim 5, characterized in that, The weight ratio of isooctyl acrylate to isobornyl acrylate is 4:

1.

7. The preparation method of the fire extinguishing film according to claim 5, characterized in that, The weight ratio of isooctyl acrylate to isobornyl acrylate is 2:

1.

8. The preparation method of the fire extinguishing film according to claim 1, characterized in that, Meet at least one of the following conditions: The fire extinguishing capsules account for 50% - 200% of the weight of the mixed base material; The fire extinguishing capsules include a shell and fire extinguishing contents inside the shell, and the fire extinguishing contents are selected from NOVEC1230, heptafluorobutyric anhydride, ethyl heptafluorobutyrate, tetradecafluorohexane, and tetrachloro-perfluoro-6-methyl-3,5-dioxoheptane, and the volatilization temperature of heptafluorobutyric anhydride, ethyl heptafluorobutyrate, tetradecafluorohexane, and tetrachloro-perfluoro-6-methyl-3,5-dioxoheptane is above 45°C.

9. A fire extinguishing film, characterized in that, The fire extinguishing film is prepared by the preparation method described in claim 1.

10. Use of the fire extinguishing film prepared by the preparation method according to any one of claims 1-8 or the fire extinguishing film according to claim 9 in preventing a storage device from catching fire, characterized in that, The fire extinguishing film is covered on the outer peripheral surface of the energy storage device.

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