Halogen-free epoxy resin composition, aerogel packaging film, preparation method and application

Abstract

The invention relates to a halogen-free epoxy resin composition, an aerogel packaging film as well as a preparation method and application of the halogen-free epoxy resin composition and the aerogel packaging film. The halogen-free epoxy resin composition comprises the following components in parts by solid weight: 10-25 parts of halogen-free bisphenol A epoxy resin; 10 to 30 parts of halogen-free polyurethane modified epoxy resin; 10-20 parts of halogen-free acrylic acid modified epoxy resin; 10 to 35 parts of a toughening agent; 20 to 35 parts of a halogen-free flame retardant; 1-10 parts of a curing agent; 0.01 to 1 part of a curing accelerator; and 0.01-5 parts of a stabilizing agent. The halogen-free epoxy resin composition can be used for preparing an aerogel packaging film, and does not adhere to a pasted object at room temperature; the halogen-free flame-retardant polypropylene material has the advantages that the halogen-free flame-retardant polypropylene material can activate reaction at low temperature, has high peel strength and shear strength and excellent aging resistance, and meets the requirement of UL94 V-0 level in flame retardance; the product does not lose efficacy after long-term storage at room temperature, and does not increase logistics and storage cost.

Description

Technical Field

[0001] This invention relates to the field of encapsulation film technology, specifically to a halogen-free epoxy resin composition, an aerogel encapsulation film, its preparation method, and its application. Background Technology

[0002] Aerogels are highly dispersed solid materials composed of a nanoporous network structure formed by the aggregation of colloidal particles or polymer molecules through a sol-gel method, with gaseous dispersion media filling the pores. Aerogels are lightweight, with a thermal conductivity typically ranging from 0.015 to 0.024 W / (m·K), exhibiting excellent thermal insulation properties and superior flame retardant performance, achieving a UL94 V0 rating. In the field of automotive new energy batteries, aerogel composite materials are widely used between cells / modules, serving as thermal insulation and preventing mutual compression and friction between adjacent battery modules, thus mitigating the thermal runaway problem of battery systems to some extent.

[0003] However, aerogel is fragile, prone to powdering and detachment. It needs to be wrapped with an encapsulation film during use to prevent the powder from affecting the battery and to ensure the safety of the aerogel assembly process and its lifespan in the battery pack.

[0004] Currently, most common aerogel encapsulation films are made by coating an adhesive onto a substrate. The substrate is typically PET or polyimide film, and various adhesive systems are used. Acrylic adhesives have a long shelf life at room temperature and can bond to the substrate at room temperature, but their peel strength is relatively low, generally not exceeding 0.68 N / mm, and their aging resistance is poor, only ensuring no blistering or delamination at 65℃ / 90%RH / 168h. Furthermore, acrylic encapsulation films have the problem of excessive initial tack, affecting positioning during processing and making it difficult to tear and repair after misalignment. Polyurethane adhesives have very low initial tack, but their peel strength and shear strength are also low, not exceeding 0.8 N / mm and 1.6 MPa respectively, and their aging resistance is not mentioned. Epoxy resin adhesives have good processability, high bonding strength, low shrinkage, excellent resistance to media, and good electrical insulation properties. After complete curing, they have high peel and shear strength, strong aging resistance, and are not easily delaminated even after immersion in organic solvents. However, conventional epoxy resin adhesives have a short shelf life at room temperature and often need to be stored at low temperature (0-10℃), which limits their use and increases logistics and warehousing costs. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the primary objective of this invention is to provide a halogen-free epoxy resin composition that can be used to prepare aerogel encapsulation films. This composition is non-sticky at room temperature and will not adhere to the substrate. It can activate the reaction at lower temperatures and also possesses high peel strength and shear strength, excellent aging resistance, and flame retardancy meeting the UL94 V-0 rating requirements. Furthermore, it can be stored at room temperature for extended periods without loss of effectiveness, thus not increasing logistics and warehousing costs.

[0006] A second object of the present invention is to provide an aerogel encapsulation film prepared from the halogen-free epoxy resin composition.

[0007] A third objective of this invention is to provide a method for preparing the aerogel encapsulation film.

[0008] A fourth objective of this invention is to provide applications of the aerogel encapsulation film.

[0009] To achieve the first objective of this invention, this invention provides a halogen-free epoxy resin composition, comprising the following components by solid weight: 10-25 parts of halogen-free bisphenol A type epoxy resin; 10-30 parts of halogen-free polyurethane modified epoxy resin; 10-20 parts of halogen-free acrylic modified epoxy resin; 10-35 parts of toughening agent; 20-35 parts of halogen-free flame retardant; 1-10 parts of curing agent; 0.01-1 part of curing accelerator; and 0.01-5 parts of stabilizer.

[0010] In some embodiments of the present invention, the halogen-free polyurethane modified epoxy resin is synthesized by synthesizing a polyurethane prepolymer from a polyhydroxy compound and a polyisocyanate, and then grafting the polyurethane prepolymer with a first epoxy resin; or it is synthesized by simultaneously polymerizing a polyhydroxy compound, a polyisocyanate and a first epoxy resin bulk to form a halogen-free polyurethane modified epoxy resin.

[0011] In some embodiments of the present invention, the halogen-free acrylic acid modified epoxy resin is prepared by grafting (meth)acrylic acid onto the methylene or methine of the second epoxy resin.

[0012] In some embodiments of the present invention, the toughening agent is at least one of nitrile rubber, styrene-butadiene rubber, butadiene rubber, ethylene propylene rubber, polyolefin resin, polyamide-imide resin, and polyurethane toughening agent.

[0013] In some embodiments of the present invention, the halogen-free flame retardant is at least one of aluminum hydroxide, magnesium hydroxide, organophosphates, and phosphonates.

[0014] In some embodiments of the present invention, the curing agent is at least one of linear phenolic resin curing agent, linear bisphenol A type phenolic curing agent, linear o-cresol formaldehyde resin curing agent, 4,4'-diaminodiphenylmethane, m-phenylenediamine, and m-phenylenediamine.

[0015] In some embodiments of the present invention, the curing accelerator is at least one of microencapsulation curing agents, boron trifluoride, imidazole, or derivatives thereof; imidazole or derivatives thereof are selected from at least one of the compounds shown in the following structural formulas: , , , , , .

[0016] In some embodiments of the present invention, the stabilizer is a borate ester or a cyclic borate ester compound.

[0017] In some embodiments of the present invention, the halogen-free polyurethane modified epoxy resin is at least one of HyPox UA 10 and HyPox UA11.

[0018] In some embodiments of the present invention, the halogen-free acrylic modified epoxy resin is at least one of A102 and B-151DT.

[0019] In some embodiments of the present invention, the nitrile rubber is CTBN 1300×8, the styrene-butadiene rubber is Buna VSL5025-2 HM, the butadiene rubber is BR-9000, the ethylene propylene rubber is EPDM6950, the polyolefin resin is AffinityTMGA1950, the polyamide-imide resin is Torlon® 4203L, and the polyurethane toughening agent is Desmocap11A.

[0020] In some embodiments of the present invention, the flame retardant is a mixture of at least one of aluminum hydroxide and magnesium hydroxide and at least one of organic phosphate ester and phosphonate in a mass ratio of 1:(0.8~1.2).

[0021] In some embodiments of the present invention, aluminum hydroxide is MARTINAL® ON-906, magnesium hydroxide is MAGNIFIN® H-5 IV, organophosphate is PX-200, and hypophosphite is OP930.

[0022] In some embodiments of the present invention, the linear phenolic resin curing agent is at least one of TD-2131, KAYAHARD GPH-65, KAYAHARD GPH-103, and KAYAHARD KTG-105; the linear bisphenol A type phenolic curing agent is at least one of VH-4150 and KH-6021; the linear o-cresol formaldehyde resin curing agent is at least one of KA-1160 and KA-1165; 4,4'-diaminodiphenylmethane is ANCAMINE® DL-50; m-phenylenediamine is MPD; and m-phenylenediamine is MXDA.

[0023] In some embodiments of the present invention, the microcapsule curing agent is at least one of HX-3722 and HX-3921HP, boron trifluoride is OMICURE BC-120, and imidazole or its derivative is at least one of SIZ, 2MZ-H, and 1B2MZ.

[0024] In some embodiments of the present invention, the stabilizer is at least one of QXA07, L07N, and STA-1000.

[0025] In some embodiments of the present invention, the halogen-free epoxy resin composition further includes an organic solvent.

[0026] In some embodiments of the present invention, the organic solvent is at least one selected from toluene, acetone, butanone, cyclohexanone, xylene, propylene glycol methyl ether, propylene glycol methyl ether acetate, N',N'-dimethylformamide, N',N'-dimethylacetamide, and dimethyl sulfoxide.

[0027] In some embodiments of the present invention, halogen-free bisphenol A type epoxy resin, halogen-free polyurethane modified epoxy resin, halogen-free acrylic modified epoxy resin, toughening agent, halogen-free flame retardant, curing agent, curing accelerator and stabilizer are dispersed in an organic solvent to form a suspension slurry, the rotational viscosity of the suspension slurry being 500~2000 cps.

[0028] In some embodiments of the present invention, the amounts of each component are as follows: 16-18 parts of halogen-free bisphenol A type epoxy resin; 13-15 parts of halogen-free polyurethane modified epoxy resin; 12-14 parts of halogen-free acrylic modified epoxy resin; 20-21 parts of toughening agent; 28-29 parts of halogen-free flame retardant; 4.7-5.2 parts of curing agent; 0.5-0.6 parts of curing accelerator; and 0.8-2.2 parts of stabilizer.

[0029] To achieve the second objective of the present invention, the present invention provides an aerogel encapsulation film comprising a halogen-free epoxy resin composition layer; the halogen-free epoxy resin composition layer is formed from the halogen-free epoxy resin composition described in any of the above embodiments.

[0030] In some embodiments of the present invention, the aerogel encapsulation film further includes a PET film and a PET protective film disposed on both sides of the halogen-free epoxy resin composition layer.

[0031] In some embodiments of the present invention, the PET film is transparent, black or white, and the thickness of the PET film is 3~100μm.

[0032] In some embodiments of the present invention, the halogen-free epoxy resin composition layer is an opaque adhesive layer with a coating thickness of 3~100μm.

[0033] In some embodiments of the present invention, the PET protective film is transparent, black or white, and the thickness of the PET protective film is 3~100μm.

[0034] In some embodiments of the present invention, the halogen-free epoxy resin composition layer is formed by drying the halogen-free epoxy resin composition.

[0035] To achieve the third objective of this invention, this invention provides a method for preparing an aerogel encapsulation film as described in any of the above embodiments, comprising the following steps: dissolving each component of a halogen-free epoxy resin composition in an organic solvent, mixing to form a suspension slurry, and coating the suspension slurry onto a PET film using a coating device; passing the PET film coated with the suspension slurry through an oven, heating it at 70~160℃ for 2~6 minutes to dry it, thereby forming a halogen-free epoxy resin composition layer containing a solvent-free solid film; then, applying a PET protective film at 50~90℃ and 0.05~2.0MPa, and finally winding it up to obtain the aerogel encapsulation film.

[0036] In some embodiments of the present invention, the suspension slurry is prepared by uniformly mixing the components together using at least one of a grinding device or a high-speed stirring and dispersing device.

[0037] In some embodiments of the present invention, the rotational viscosity of the suspension slurry is 500~2000 cps.

[0038] To achieve the fourth objective of the present invention, the present invention provides a battery including an aerogel disposed between adjacent battery modules, the aerogel being encapsulated by an aerogel encapsulation film; the aerogel encapsulation film is any of the aerogel encapsulation films described above.

[0039] Compared with the prior art, the present invention can achieve the following beneficial effects: The halogen-free epoxy resin composition and the aerogel encapsulation film prepared using the present invention employ polyurethane-modified epoxy resin and acrylic-modified epoxy resin, which greatly reduces the tackiness of the aerogel encapsulation film and prevents it from sticking to the substrate at room temperature. Combined with a low-temperature latent curing agent, the adhesive can be activated at relatively low temperatures (80-120℃), exhibiting high peel strength and shear strength, excellent aging resistance, and flame retardancy meeting the UL94 V-0 rating requirements. Furthermore, a stabilizer is used to improve the room temperature storage properties of the adhesive, allowing the aerogel encapsulation film to be stored at room temperature for extended periods without failure, thus not increasing logistics and warehousing costs. Attached Figure Description

[0040] Figure 1 This is a schematic diagram of the structure of an embodiment of the aerogel encapsulation film of the present invention.

[0041] In the figure, 1-PET film, 2-halogen-free epoxy resin composition layer, 3-PET protective film.

[0042] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. Detailed Implementation

[0043] This invention provides a halogen-free epoxy resin composition and an aerogel encapsulation film prepared using the same. The halogen-free epoxy resin composition and aerogel encapsulation film can be used to encapsulate aerogel, preventing powder shedding and detachment. The aerogel encapsulated by this halogen-free epoxy resin composition and aerogel encapsulation film can be used in battery systems to solve the thermal runaway problem of battery systems, ensuring safety during aerogel assembly and extending its service life in the battery pack. The halogen-free epoxy resin composition and aerogel encapsulation film are not cured when encapsulating aerogel, allowing for encapsulation of different aerogel shapes. After encapsulation, it can be cured at low temperatures before or after placement in the battery system to maintain a specific shape; low-temperature curing does not affect device function. Of course, the aerogel encapsulated by the halogen-free epoxy resin composition and aerogel encapsulation film of this embodiment can also be used in other fields.

[0044] Specifically, the halogen-free epoxy resin composition of this embodiment, calculated by solid weight, comprises the following components in parts by weight: 10-25 parts of halogen-free bisphenol A type epoxy resin; 10-30 parts of halogen-free polyurethane modified epoxy resin; 10-20 parts of halogen-free acrylic modified epoxy resin; 10-35 parts of toughening agent; 20-35 parts of halogen-free flame retardant; 1-10 parts of curing agent; 0.01-1 part of curing accelerator; and 0.01-5 parts of stabilizer.

[0045] The halogen-free bisphenol A epoxy resin is present in quantities of 10-25 parts, for example, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25 parts, etc. The halogen-free bisphenol A epoxy resin can be a commonly used bisphenol A epoxy resin in this field.

[0046] The halogen-free polyurethane modified epoxy resin is used in quantities of 10-30 parts, for example, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, and 30 parts. By using the halogen-free polyurethane modified epoxy resin and toughening agent together and adjusting the formulation, the toughening effects of both can be fully utilized. Furthermore, the halogen-free polyurethane modified epoxy resin can also increase the crosslinking density of the cured product to a certain extent, thereby improving the cohesive strength of the adhesive layer and ultimately enhancing the peel strength of the cover film.

[0047] The amount of halogen-free acrylic-modified epoxy resin is 10-20 parts, for example, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20 parts, etc. Acrylic-modified epoxy resin has better weather resistance, chemical resistance, and heat resistance, as well as excellent mechanical strength and electrical insulation properties.

[0048] The toughening agent is present in quantities of 10-35 parts, for example, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, etc. The toughening agent improves the toughness of the composition.

[0049] The halogen-free flame retardant is present in quantities of 20-35 parts, for example, 20 parts, 21 parts, 22 parts, 23 parts, 24 parts, 25 parts, 26 parts, 27 parts, 28 parts, 29 parts, 30 parts, 31 parts, 32 parts, 33 parts, 34 parts, 35 parts, etc. The halogen-free flame retardant can improve the flame retardant properties of the composition.

[0050] The curing agent is prepared in quantities of 1-10 parts, for example, 1 part, 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, etc. The curing agent can react with halogen-free bisphenol A type epoxy resin, halogen-free polyurethane modified epoxy resin, and halogen-free acrylic modified epoxy resin to form cross-linked cured products, thereby improving the mechanical strength of the cured products.

[0051] The curing accelerator is used in amounts of 0.01-1 part, for example, 0.01 part, 0.1 part, 0.2 part, 0.3 part, 0.4 part, 0.5 part, 0.6 part, 0.7 part, 0.8 part, 0.9 part, 1 part, etc. The curing accelerator helps to lower the curing reaction temperature.

[0052] The stabilizer is present in amounts of 0.01-5 parts, for example, 0.01 parts, 0.1 parts, 0.2 parts, 0.3 parts, 0.4 parts, 0.5 parts, 0.6 parts, 0.7 parts, 0.8 parts, 0.9 parts, 1 part, 2 parts, 3 parts, 4 parts, 5 parts, etc. The stabilizer can inhibit the room temperature reactivity of the composition and extend the shelf life of the one-component epoxy system.

[0053] This embodiment prepared a modified epoxy gel encapsulation film with low initial tack by adjusting the adhesive formulation. It is non-sticky at room temperature and will not adhere to the substrate. The reaction is activated at relatively low temperatures (80-120°C), and it also exhibits high peel and shear strength, excellent aging resistance, and meets the UL94 V-0 flame retardant rating. Furthermore, the prepared modified epoxy gel encapsulation film can be stored at room temperature for extended periods without failure, without increasing logistics and storage costs. The halogen-free epoxy resin composition of this embodiment is suitable for manufacturing aerogel encapsulation films.

[0054] In some examples, the modification of halogen-free polyurethane-modified epoxy resin can be achieved by either synthesizing a polyurethane prepolymer from a polyhydroxy compound and a polyisocyanate, and then grafting the prepolymer onto a first epoxy resin to synthesize the halogen-free polyurethane-modified epoxy resin, where the first epoxy resin can be any existing epoxy resin; or by using bulk simultaneous polymerization to directly synthesize the halogen-free polyurethane-modified epoxy resin. Regardless of which method is used to prepare the halogen-free polyurethane-modified epoxy resin, as long as the molecule contains polyurethane segments and meets the performance requirements, it can be used in the formulation of this embodiment.

[0055] Commercially available halogen-free polyurethane-modified epoxy resins include HyPox UA 10 and HyPox UA 11 (manufactured by CVC Thermosetting Specialty Materials, Inc., USA).

[0056] In some examples, halogen-free acrylic modified epoxy resin is produced by dissolving a second epoxy resin in a suitable solvent, adding acrylic monomers (such as methacrylic acid, acrylic acid, etc.) and an initiator, and heating the mixture to initiate graft polymerization of the acrylic monomer with the -CH2- or -CH- groups in the second epoxy resin molecule, thereby generating a modified epoxy resin containing carboxylic acid groups. The second epoxy resin can be any existing epoxy resin, and it can be the same as or different from the first epoxy resin.

[0057] Commercially available halogen-free acrylic modified epoxy resins include A102 (Guangzhou Xieyu New Material Technology Co., Ltd.) and B-151DT (Guangdong Boxin New Material Technology Co., Ltd.). B-151DT is preferred as it helps improve peel strength and peel strength retention.

[0058] In some examples, the toughening agent is one or more of nitrile rubber, styrene-butadiene rubber, butadiene rubber, ethylene propylene rubber, polyolefin resin, polyamide-imide resin, and polyurethane.

[0059] Commercially available nitrile rubbers include CTBN 1300×8 (manufactured by CVC Thermosetting Specialty Materials, Inc., USA), styrene-butadiene rubbers include Buna VSL 5025-2 HM (manufactured by Lanxess), butadiene rubbers include BR-9000 (manufactured by Sinopec), ethylene propylene rubbers include EPDM6950 (manufactured by Lanxess), polyolefin resins include Affinity™ GA1950 (manufactured by Dow Chemical Company, USA), polyamide-imide resins include Torlon® 4203L (manufactured by SOLVAY, USA), and polyurethane toughening agents and elastomers include Desmocap11A (manufactured by Covestro).

[0060] In some examples, the flame retardant is one or more of aluminum hydroxide, magnesium hydroxide, organophosphates, and phosphonates.

[0061] Commercially available flame retardants include, but are not limited to, MARTINAL® ON-906, MAGNIFIN® H-5 IV (manufactured by JMHuber Corporation), PX-200 (manufactured by Daihachi Chemical Co., Ltd., Japan), and OP930 (manufactured by Clariant GmbH, Germany).

[0062] In some examples, the curing agent is one or more of the following: linear phenolic resin curing agent, linear bisphenol A type phenolic curing agent, linear o-cresol formaldehyde resin curing agent, 4,4'-diaminodiphenylmethane, m-phenylenediamine, and m-phenylenediamine.

[0063] Commercially available linear phenolic resin curing agents include TD-2131 (manufactured by DIC Japan), KAYAHARD GPH-65, KAYAHARD GPH-103, and KAYAHARD KTG-105 (manufactured by Nippon Kayaku Co., Ltd., Japan); linear bisphenol A type phenolic curing agents include VH-4150 and KH-6021 (manufactured by DIC Japan); linear o-cresol formaldehyde resin curing agents include KA-1160 and KA-1165 (manufactured by DIC Japan); 4,4'-diaminodiphenylmethane is ANCAMINE® DL-50 (manufactured by Evonik Industries AG); m-phenylenediamine is MPD (manufactured by Jiangsu Shengbang New Materials Co., Ltd.); and m-phenylenediamine MXDA (manufactured by Mitsubishi Gas Chemical Trading, Inc., Japan).

[0064] In some examples, the curing accelerator is one or more of microencapsulated curing agents, boron trifluoride, and / or imidazoles or their derivatives containing the following structures.

[0065] , , , , , .

[0066] Commercially available microcapsule curing agents include HX-3722 and HX-3921HP (manufactured by ASAHI KASEI CORPORATION, Japan), boron trifluoride is available as OMICURE BC-120 (manufactured by CVC Thermosetting Specialty Materials, USA), and imidazole or its derivatives include SIZ, 2MZ-H, and 1B2MZ (manufactured by SHIKOKU CHEMICALS CORPORATION, Japan).

[0067] In some examples, the stabilizer is a borate ester or cyclic borate ester compound that inhibits the room temperature reaction of the composition through the coordination of boron atoms with the curing agent or curing accelerator.

[0068] Commercially available stabilizers include QXA07 (Shanghai Qianxing Materials Technology Co., Ltd.), L07N (Shikoku Chemical Industry Co., Ltd., Japan), and STA-1000 (Shanghai Wujing Chemical Technology Co., Ltd.). STA-1000 is preferred as it helps improve peel strength and peel strength retention.

[0069] In some examples, the halogen-free epoxy resin composition also contains an appropriate amount of organic solvent. The organic solvent may be one or more of toluene, acetone, butanone, cyclohexanone, xylene, propylene glycol methyl ether, propylene glycol methyl ether acetate, N',N'-dimethylformamide, N',N'-dimethylacetamide, and dimethyl sulfoxide.

[0070] In some examples, this embodiment also provides an aerogel encapsulation film prepared from a halogen-free epoxy resin composition, such as... Figure 1 As shown, it includes a PET film 1, a halogen-free epoxy resin composition layer 2 coated on the PET film 1, and a PET protective film 3 adhered to the halogen-free epoxy resin composition layer 2.

[0071] In some examples, the PET film 1 is transparent, black, or white, and its thickness is 3-100 μm. In some examples, the halogen-free epoxy resin composition layer 2 is an opaque adhesive layer; the composition contains components such as solid flame retardants, which cause the halogen-free epoxy resin composition layer 2 to be opaque, and the coating thickness is 3-100 μm. The PET protective film 3 is transparent, black, or white, and its thickness is 3-100 μm.

[0072] In some examples, the components of the halogen-free epoxy resin composition are dissolved and mixed in an organic solvent to form a suspension slurry. This suspension slurry is then coated onto a PET film 1 using a coating device. The PET film 1 coated with the suspension slurry is then dried in an oven at 70-160°C for 2 to 6 minutes to form a layer 2 of the halogen-free epoxy resin composition containing a solvent-free solid film. Subsequently, a PET protective film 3 is laminated at 50-90°C and 0.05-2.0 MPa, and the film is then wound up to obtain an aerogel encapsulation film.

[0073] In some examples, the suspension slurry is prepared by uniformly mixing the resin components, inorganic solid components, curing agent, and organic solvent in a halogen-free epoxy resin composition using grinding equipment such as a sand mill and dispersing equipment such as a high-speed mixer.

[0074] In some examples, the rotational viscosity of the suspension slurry is preferably 500-2000 cps to obtain good processability and ensure that no appearance defects occur during coating.

[0075] The technical solution of the present invention will be further described in detail below with reference to specific embodiments.

[0076] The formulations of Examples 1 to 5 and Comparative Examples 1 to 4 are shown in Tables 1 and 2 below. The preparation methods for each example and comparative example are as follows: The components were dissolved in toluene, ground in a sand mill and mixed and dispersed using a high-speed mixer to form a suspension slurry with a rotational viscosity of 1000 cps. The suspension slurry was coated onto a PET film 1 using a coating device, and then dried in an oven at 120°C for 5 minutes to form a halogen-free epoxy resin composition layer 2 containing a solvent-free solid film. Then, a PET protective film 3 was laminated at 80°C and 1.0 MPa, and the film was wound up to obtain an aerogel encapsulation film.

[0077] The aerogel encapsulation films prepared in each embodiment and comparative example were subjected to performance tests. The specific test methods are as follows.

[0078] (1) Thickness: Tested according to GB / T 7125-2014.

[0079] (2) Peel strength: The peel strength between the aerogel encapsulation film and the copper foil was tested according to the IPC-TM-650 2.4.9 method.

[0080] (3) Shear strength: tested according to ASTM-D-1002 method.

[0081] (4) Ring initial tack: Tested according to GB / T 31125-2014.

[0082] (5) Flame retardancy: Tested according to UL94 method.

[0083] (6) Storage stability: The aerogel encapsulation film was stored at 23℃ / 65%RH for a period of time. After that, a sample was prepared and a peel strength test was conducted to test the rate of degradation.

[0084] (7) Moisture and heat resistance reliability: The aerogel encapsulation film is applied to the aerogel and then hot-pressed. After the test piece is prepared, it is kept at 85℃ / 85%RH for 500 hours. After being taken out and cooled to room temperature, the appearance is observed to see if there is delamination or blistering.

[0085] The measured results are shown in Tables 1 and 2 below.

[0086] Table 1. Formulation examples of halogen-free epoxy resin compositions and the properties of the prepared aerogel encapsulation films.

[0087] Table 2 Comparative Examples of Halogen-Free Epoxy Resin Composition Formulations and Properties of the Prepared Aerogel Encapsulation Films

[0088] The test results show that the halogen-free epoxy resin composition of the present invention and the prepared aerogel encapsulation film not only have low initial tack and do not adhere to the substrate at room temperature, but also activate the reaction at relatively low temperatures (80-120°C), and have high peel strength and shear strength, excellent aging resistance, and flame retardancy that meets the requirements of UL94 V-0 level. On the other hand, the use of stabilizers improves the room temperature storage properties of the adhesive, and the aerogel encapsulation film can be stored at room temperature for a long time without failure, without increasing logistics and warehousing costs.

[0089] Finally, it should be emphasized that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A halogen-free epoxy resin composition, characterized in that... Based on solid weight parts, it includes the following components: 10-25 parts of halogen-free bisphenol A type epoxy resin; 10-30 parts of halogen-free polyurethane modified epoxy resin; 10-20 parts of halogen-free acrylic modified epoxy resin; Toughening agent 10-35 parts; 20-35 parts of halogen-free flame retardant; 1-10 parts of curing agent; Curing accelerator 0.01~1 part; Stabilizer 0.01~5 parts.

2. The halogen-free epoxy resin composition according to claim 1, characterized in that: The halogen-free polyurethane modified epoxy resin is synthesized by synthesizing a polyurethane prepolymer from polyhydroxy compounds and polyisocyanates, and then grafting the polyurethane prepolymer with a first epoxy resin; or it is synthesized by simultaneously polymerizing polyhydroxy compounds, polyisocyanates and the first epoxy resin bulk to form a halogen-free polyurethane modified epoxy resin. The halogen-free acrylic acid modified epoxy resin is prepared by grafting (meth)acrylic acid onto the methylene or methine of the second epoxy resin. The toughening agent is at least one of nitrile rubber, styrene-butadiene rubber, butadiene rubber, ethylene propylene rubber, polyolefin resin, polyamide-imide resin, and polyurethane toughening agent; The halogen-free flame retardant is at least one of aluminum hydroxide, magnesium hydroxide, organophosphates, and phosphonates. The curing agent is at least one of linear phenolic resin curing agent, linear bisphenol A type phenolic curing agent, linear o-cresol formaldehyde resin curing agent, 4,4'-diaminodiphenylmethane, m-phenylenediamine, and m-phenylenediamine; The curing accelerator is at least one of microencapsulation curing agents, boron trifluoride, imidazole, or derivatives thereof; imidazole or derivatives thereof are selected from at least one of the compounds shown in the following structural formulas: 、 、 、 、 、 ； The stabilizer is a borate ester or a cyclic borate ester compound.

3. The halogen-free epoxy resin composition according to claim 2, characterized in that: The halogen-free polyurethane modified epoxy resin is at least one of HyPox UA 10 and HyPox UA 11. The halogen-free acrylic modified epoxy resin is at least one of A102 and B-151DT; The nitrile rubber is CTBN 1300×8, the styrene-butadiene rubber is Buna VSL 5025-2 HM, the butadiene rubber is BR-9000, the ethylene propylene rubber is EPDM6950, the polyolefin resin is AffinityTM GA1950, the polyamide-imide resin is Torlon® 4203L, and the polyurethane toughening agent is Desmocap11A. The flame retardant is a mixture obtained by mixing at least one of aluminum hydroxide and magnesium hydroxide and at least one of organic phosphate ester and phosphonate in a mass ratio of 1:(0.8~1.2); The aluminum hydroxide is MARTINAL® ON-906, the magnesium hydroxide is MAGNIFIN® H-5 IV, the organophosphate is PX-200, and the phosphonate is OP930; The linear phenolic resin curing agent is at least one of TD-2131, KAYAHARD GPH-65, KAYAHARD GPH-103, and KAYAHARD KTG-105; the linear bisphenol A type phenolic curing agent is at least one of VH-4150 and KH-6021; the linear o-cresol formaldehyde resin curing agent is at least one of KA-1160 and KA-1165; the 4,4'-diaminodiphenylmethane is ANCAMINE® DL-50; the m-phenylenediamine is MPD; and the m-phenylenediamine is MXDA. The microcapsule curing agent is at least one of HX-3722 and HX-3921HP, the boron trifluoride is OMICURE BC-120, and the imidazole or its derivative is at least one of SIZ, 2MZ-H, and 1B2MZ. The stabilizer is at least one of QXA07, L07N, and STA-1000.

4. A halogen-free epoxy resin composition according to any one of claims 1 to 3, characterized in that: The halogen-free epoxy resin composition also includes an organic solvent; The organic solvent is at least one of toluene, acetone, butanone, cyclohexanone, xylene, propylene glycol methyl ether, propylene glycol methyl ether acetate, N',N'-dimethylformamide, N',N'-dimethylacetamide, and dimethyl sulfoxide; The halogen-free bisphenol A type epoxy resin, the halogen-free polyurethane modified epoxy resin, the halogen-free acrylic modified epoxy resin, the toughening agent, the halogen-free flame retardant, the curing agent, the curing accelerator, and the stabilizer are dispersed in the organic solvent to form a suspension slurry, and the rotational viscosity of the suspension slurry is 500~2000 cps.

5. A halogen-free epoxy resin composition according to any one of claims 1 to 3, characterized in that... The amounts of each component are as follows: 16-18 parts of halogen-free bisphenol A type epoxy resin; 13-15 parts of halogen-free polyurethane modified epoxy resin; 12-14 parts of halogen-free acrylic modified epoxy resin; 20-21 parts of toughening agent; 28-29 parts of halogen-free flame retardant; 4.7-5.2 parts of curing agent; 0.5-0.6 parts of curing accelerator; and 0.8-2.2 parts of stabilizer.

6. An aerogel encapsulation film, characterized in that: The aerogel encapsulation film includes a halogen-free epoxy resin composition layer; The halogen-free epoxy resin composition layer is formed from the halogen-free epoxy resin composition according to any one of claims 1 to 5.

7. The aerogel encapsulation film according to claim 6, characterized in that: The aerogel encapsulation film also includes a PET film and a PET protective film respectively disposed on both sides of the halogen-free epoxy resin composition layer; The PET film is transparent, black, or white, and the thickness of the PET film is 3~100μm; The halogen-free epoxy resin composition layer is an opaque adhesive layer with a coating thickness of 3~100μm; The PET protective film is transparent, black, or white, and its thickness is 3~100μm; The halogen-free epoxy resin composition layer is formed by drying the halogen-free epoxy resin composition.

8. A method for preparing an aerogel encapsulation film according to claim 6 or 7, characterized in that... Includes the following steps: Each component of the halogen-free epoxy resin composition is dissolved in an organic solvent and mixed to form a suspension slurry. The suspension slurry is then coated onto a PET film using a coating device. The PET film coated with the suspension slurry is then dried in an oven at 70-160°C for 2-6 minutes to form a halogen-free epoxy resin composition layer containing a solvent-free solid film. A PET protective film is then applied at 50-90°C and 0.05-2.0 MPa, and the film is then wound up to obtain an aerogel encapsulation film.

9. The preparation method according to claim 8, characterized in that: The suspension slurry is prepared by uniformly mixing the components together using at least one of a grinding device and a high-speed stirring and dispersing device. The rotational viscosity of the suspension is 500~2000 cps.

10. A battery comprising an aerogel disposed between adjacent battery modules, characterized in that: The aerogel is encapsulated by an aerogel encapsulation film; the aerogel encapsulation film is the aerogel encapsulation film according to claim 6 or 7, or the aerogel encapsulation film prepared by the preparation method according to claim 8 or 9.

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