Halogen-free epoxy resin composition, low-temperature hot-pressing adhesive film, preparation method and application

Abstract

The invention relates to a halogen-free epoxy resin composition, a low-temperature hot-pressing adhesive film as well as a preparation method and application of the halogen-free epoxy resin composition. The halogen-free epoxy resin composition comprises the following components in parts by weight: 10-25 parts of halogen-free bisphenol A epoxy resin; 10 to 25 parts of halogen-free polyurethane modified epoxy resin; 5-15 parts of halogen-free naphthalene type epoxy resin; 5-15 parts of halogen-free organic silicon modified epoxy resin; 5-15 parts of halogen-free phosphorus-containing epoxy resin; 15 to 40 parts of a toughening agent; 15 to 30 parts of a halogen-free flame retardant; 1-10 parts of a curing agent; 0.01 to 1 part of a curing accelerator; a proper amount of organic solvent; wherein the curing agent is at least one of a linear phenolic resin curing agent, a linear bisphenol A type phenolic curing agent, a linear o-cresol formaldehyde resin curing agent, 4, 4 '-diamino diphenylmethane, m-phenylenediamine and m-xylylenediamine. The composition can activate the reaction at 80-120 DEG C, reduces the reaction temperature, meets the requirements of low-temperature operation conditions, has good bonding, insulating and other properties, passes a 300 DEG C / 30s high-temperature impact test, and has very high reliability.

Description

Technical Field

[0001] The present invention relates to the field of adhesives, and in particular to a halogen-free epoxy resin composition, a low-temperature hot-pressed adhesive film, a preparation method and applications thereof. Background Art

[0002] Some substrates of the circuit boards inside electronic devices are encapsulated and protected with glue. For environmental protection and yield considerations, many manufacturers are gradually using film instead of glue to encapsulate the circuits. This not only controls glue overflow and avoids contamination of the circuits, thereby improving yield, but also greatly improves the flexibility and convenience of production operations. Currently, the adhesive films used in the market are mainly epoxy resin films: for example, CN101538397A, CN102127289A, and CN1537906A disclose methods for preparing adhesive films and covering films using epoxy resin. The adhesive films or covering films prepared by this method have excellent heat shock resistance (heat resistance temperature and duration exceed 280°C / 30 seconds); for example, the adhesive films of CN117487317A, CN111995956A, and CN114729234A all show high reliability after being cured and subjected to high temperature and high humidity (85°C / 85%RH) treatment; however, the above products all require relatively high pressing and curing temperatures (>150°C), which places relatively high demands on the temperature resistance of the material and increases energy consumption costs. In addition, the products are prone to generate large internal stresses during the high-temperature molding process, which may cause problems such as material delamination and blistering, and loss of dimensional accuracy. Although patents CN106674901A and CN116286774A have conventional properties such as bonding after low-temperature curing (120°C), their heat shock resistance and reliability are unknown.

[0003] Furthermore, within the new energy vehicle industry, the development of new energy vehicles has significantly boosted the research and production of lithium batteries. During lithium battery production, specialized adhesive tapes are used to secure and protect components such as the cells, tabs, and terminations. These tapes must possess high adhesion, high-temperature resistance, electrolyte resistance, and excellent electrical insulation properties. At present, special adhesive tapes for lithium batteries mainly include acrylic esters (such as CN118530680A, CN109355025A, CN109385236A, CN119161832A, CN117535021A, CN119081598A) and thermoplastic elastomers (such as CN113913138B, CN108192532B, CN116640533A, CN117701206A). Occasionally, some adhesive tapes containing epoxy resins (such as CN111978884A, CN118374236A) are mainly made of the above two types of resins and then modified with a small amount of epoxy resin. There are almost no special adhesive tapes for lithium batteries made entirely of epoxy resin as the main material. Epoxy resin has high adhesion and excellent bonding strength to some difficult-to-adhere substrates (such as PP film, PE film, etc.). It also has excellent temperature resistance and chemical resistance, outstanding insulation properties, and its overall performance is superior to existing adhesive systems such as acrylic esters and thermoplastic elastomers. However, it is currently rarely used in the field of special adhesive tapes for lithium batteries. The main reason is that the processing temperature of tapes and films made of single-component epoxy resin adhesives is too high (>150°C), which cannot be adapted to the production process of lithium batteries.

[0004] Currently, there is an urgent need for an adhesive film that meets the requirements of low-temperature operating conditions and has good adhesion, insulation, and high-temperature impact resistance. It can be used to encapsulate and protect the circuits on the circuit board, and is also suitable for fixing and protecting components in the lithium battery production process. Summary of the Invention

[0005] In response to the shortcomings of the existing technology, the first object of the present invention is to provide a halogen-free epoxy resin composition that can activate the reaction at low temperatures (80-120°C), reducing the reaction temperature and meeting the requirements of low-temperature operating conditions. At the same time, it has good adhesion, insulation and other properties, passes the 300°C / 30s high-temperature impact test, and has high reliability.

[0006] The second object of the present invention is to provide a method for preparing the halogen-free epoxy resin composition.

[0007] The third object of the present invention is to provide a low-temperature hot-pressing adhesive film containing the halogen-free epoxy resin composition.

[0008] The fourth object of the present invention is to provide a method for preparing the low-temperature hot-pressed adhesive film.

[0009] The fifth object of the present invention is to provide applications of the low-temperature hot-pressed adhesive film.

[0010] To achieve the first object of the present invention, the present invention provides a halogen-free epoxy resin composition, which comprises the following components in parts by weight, calculated on a solid weight basis: 10 to 25 parts of a halogen-free bisphenol A epoxy resin; 10 to 25 parts of a halogen-free polyurethane-modified epoxy resin; 5 to 15 parts of a halogen-free naphthalene epoxy resin; 5 to 15 parts of a halogen-free organosilicon-modified epoxy resin; 5 to 15 parts of a halogen-free phosphorus-containing epoxy resin; 15 to 40 parts of a toughening agent; 15 to 30 parts of a halogen-free flame retardant; 1 to 10 parts of a curing agent; 0.01 to 1 part of a curing accelerator; and an appropriate amount of an organic solvent; wherein the curing agent is at least one of a linear phenolic resin curing agent, a linear bisphenol A phenolic resin curing agent, a linear o-cresol formaldehyde resin curing agent, 4,4'-diaminodiphenylmethane, m-phenylenediamine, and m-phenylenediamine.

[0011] In some embodiments of the present invention, the curing accelerator is at least one of a microcapsule curing agent, boron trifluoride, an imidazole having the following structure or a derivative thereof:

[0012] 、 、 、 、 、 ;

[0013] In the formula, R is selected from a hydrocarbon group, a substituted hydrocarbon group, a halogen, a nitro group, a carboxyl group, a hydroxyl group, an ester group, an ether bond, an aldehyde group, a ketone group or an amino group.

[0014] In some embodiments of the present invention, the linear phenolic resin curing agent is selected from at least one of TD-2131 of DIC of Japan, KAYAHARD GPH-65 of Nippon Kayaku Co., Ltd. of Japan, KAYAHARD GPH-103 of Nippon Kayaku Co., Ltd. of Japan, and KAYAHARD KTG-105 of Nippon Kayaku Co., Ltd. of Japan; the linear bisphenol A type phenolic curing agent is selected from at least one of VH-4150 of DIC of Japan and KH-6021 of DIC of Japan; the linear o-cresol formaldehyde resin curing agent is selected from at least one of KA-1160 of DIC of Japan and KA-1165 of DIC of Japan; 4,4'-diaminodiphenylmethane is selected from ANCAMINE®DL-50 of Evonik Industries AG; m-phenylenediamine is selected from MPD of Jiangsu Shengbang New Materials Co., Ltd.; and m-phenylenediamine is selected from MXDA of Mitsubishi Gas Chemical Trading, Inc. of Japan.

[0015] In some embodiments of the present invention, the curing agent accelerator is selected from at least one of microcapsule curing agent HX-3722 of ASAHI KASEI CORPORATION of Japan, microcapsule curing agent HX-3921HP of ASAHI KASEI CORPORATION of Japan, boron trifluoride OMICURE BC-120 of CVC Thermosetting Special Materials Company of the United States, imidazole or its derivative SIZ of SHIKOKU CHEMICALSCORPORATION of Japan, imidazole or its derivative 2MZ-H of SHIKOKU CHEMICALS CORPORATION of Japan, and imidazole or its derivative 1B2MZ of SHIKOKU CHEMICALS CORPORATION of Japan.

[0016] In some embodiments of the present invention, the halogen-free polyurethane modified epoxy resin is synthesized by synthesizing a polyurethane prepolymer from a polyol and a polyisocyanate, and then grafting the polyurethane prepolymer with an epoxy resin to synthesize the halogen-free polyurethane modified epoxy resin, or the halogen-free polyurethane modified epoxy resin is synthesized by bulk synchronous polymerization.

[0017] In some embodiments of the present invention, the halogen-free naphthalene epoxy resin comprises a compound represented by the following structural formula or a derivative thereof:

[0018] 、 、 、 .

[0019] In some embodiments of the present invention, the halogen-free organosilicon-modified epoxy resin is a halogen-free organosilicon-modified epoxy resin obtained by physically blending an organosilicon compound and an epoxy resin, or the halogen-free organosilicon-modified epoxy resin is a copolymer having a core-shell structure, a graft structure, or a block structure obtained by reacting the active terminal functional groups of the organosilicon compound with the epoxy groups in the epoxy resin.

[0020] In some embodiments of the present invention, the halogen-free phosphorus-containing epoxy resin is a flame-retardant epoxy resin obtained by chemically bonding a reactive phosphorus compound to an epoxy resin molecular chain. The reactive phosphorus compound is selected from the phosphinophenanthrene compound shown in the following structure:

[0021] 、 、 .

[0022] In some embodiments of the present invention, the phosphorus content of the halogen-free phosphorus-containing epoxy resin is 0.5%-16%.

[0023] 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.

[0024] In some embodiments of the present invention, 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.

[0025] In some embodiments of the present invention, the halogen-free polyurethane modified epoxy resin is selected from at least one of HyPox UA 10 and HyPox UA 11 of CVC Thermosetting Specialty Materials, Inc., USA.

[0026] In some embodiments of the present invention, the halogen-free naphthalene epoxy resin is selected from at least one of NC-7000L of Nippon Kayaku Co., Ltd., HP-4710 of DIC Corporation of Japan, and HP-4032D of DIC Corporation of Japan.

[0027] In some embodiments of the present invention, the halogen-free organosilicon-modified epoxy resin is selected from at least one of ALBIDUR® EP 2240A of Evonik Industries AG and NANOPOX® A 410 of Evonik Industries AG.

[0028] In some embodiments of the present invention, the halogen-free phosphorus-containing epoxy resin is selected from at least one of XEN-0140 produced by SHIN-A T&C of South Korea and SEN-6085 produced by SHIN-A T&C of South Korea.

[0029] In some embodiments of the present invention, the toughening agent is selected from at least one of the nitrile rubber CTBN 1300×8 of CVC Thermosetting Specialty Materials, Inc. of the United States, the styrene-butadiene rubber Buna VSL 5025-2 HM of Lanxess, the butadiene rubber of Sinopec, the ethylene-propylene rubber EPDM6950 of Lanxess, the polyolefin resin AffinityTM GA1950 of DOW, Inc. of the United States, the polyamide-imide resin Torlon® 4203L of SOLVAY, Inc. of the United States, and the polyurethane Desmocap11A of Covestro.

[0030] In some embodiments of the present invention, the halogen-free flame retardant is selected from at least one of MARTINAL® ON-906 of JM Huber Corporation, MAGNIFIN® H-5 IV of JM Huber Corporation, PX-200 of Daihachi Chemical Industry Co., Ltd. of Japan, and OP930 of Clariant of Germany.

[0031] To achieve the second object of the present invention, the present invention provides a method for preparing the halogen-free epoxy resin composition described in any of the above schemes, comprising dissolving and mixing a halogen-free bisphenol A epoxy resin, a halogen-free polyurethane-modified epoxy resin, a halogen-free naphthalene-type epoxy resin, a halogen-free organosilicon-modified epoxy resin, a halogen-free phosphorus-containing epoxy resin, a toughening agent, a halogen-free flame retardant, a curing agent and a curing accelerator in an organic solvent to form a suspension slurry.

[0032] In some embodiments of the present invention, the suspension slurry is dispersed by at least one of a sand mill and a high-speed mixer.

[0033] In some embodiments of the present invention, the rotational viscosity of the suspension slurry is 500-2000 cps.

[0034] To achieve the third purpose of the present invention, the present invention provides a low-temperature hot-pressed adhesive film, comprising a PET release film, a halogen-free epoxy resin composition layer coated on the PET release film, and a PET protective film attached to the halogen-free epoxy resin composition layer, wherein the halogen-free epoxy resin composition layer is made of a halogen-free epoxy resin composition described in any of the above schemes.

[0035] To achieve the fourth object of the present invention, the present invention provides a method for preparing the above-mentioned low-temperature hot-pressed adhesive film, using a coating device to coat a suspension slurry of a halogen-free epoxy resin composition onto a PET release film, passing the PET release film coated with the suspension slurry through an oven, heating at 70~160°C for 2~6 minutes to dry, forming a layer of the composition in a solvent-free solid adhesive film state, then applying a PET protective film under conditions of 50~90°C and 0.05~2.0MPa, and winding to obtain a low-temperature hot-pressed adhesive film.

[0036] In some embodiments of the present invention, the PET release film is colorless and transparent with a thickness of 3-100 μm; the halogen-free epoxy resin composition layer is an opaque adhesive layer with a coating thickness of 3-100 μm; and the PET protective film has a thickness of 3-100 μm.

[0037] To achieve the fifth purpose of the present invention, the present invention provides an application of the low-temperature hot-pressed adhesive film described in any of the above schemes, which is used to encapsulate and protect circuits on circuit boards, or to fix and protect components in the production process of lithium batteries.

[0038] Compared with the prior art, the present invention can achieve the following beneficial effects:

[0039] This invention primarily provides a halogen-free epoxy resin composition and a low-temperature hot-pressed adhesive film prepared using the same. By adjusting the adhesive formula, employing a halogen-free, high-performance epoxy resin composition and combining it with a low-temperature latent curing agent, an epoxy film is prepared that can be activated at low temperatures (80-120°C). This reduces the reaction temperature, meeting low-temperature operating conditions, while maintaining the epoxy resin's inherent bonding and insulation properties. The film passes a 300°C / 30s high-temperature impact test and exhibits high reliability. Furthermore, the low-temperature hot-pressed adhesive film is compatible with lithium battery production processes and meets electrolyte resistance requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 1 is a structural diagram of an embodiment of a low-temperature hot-pressed adhesive film according to the present invention.

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

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

[0043] An embodiment of the present invention provides a halogen-free epoxy resin composition, which comprises the following components, calculated in parts by solid weight: 10-25 parts of a halogen-free bisphenol A epoxy resin; 10-25 parts of a halogen-free polyurethane-modified epoxy resin; 5-15 parts of a halogen-free naphthalene epoxy resin; 5-15 parts of a halogen-free organosilicon-modified epoxy resin; 5-15 parts of a halogen-free phosphorus-containing epoxy resin; 15-40 parts of a toughening agent; 15-30 parts of a flame retardant; 1-10 parts of a curing agent; 0.01-1 parts of a curing accelerator; and an appropriate amount of an organic solvent.

[0044] In some examples, the total weight of the halogen-free bisphenol A epoxy resin, halogen-free polyurethane modified epoxy resin, halogen-free naphthalene epoxy resin, halogen-free silicone modified epoxy resin, halogen-free phosphorus-containing epoxy resin, toughening agent, flame retardant, curing agent and curing accelerator in the halogen-free epoxy resin composition is 100 parts, which is convenient for material dosage control and weighing.

[0045] In some examples, the halogen-free epoxy resin composition is mainly composed of halogen-free bisphenol A epoxy resin, halogen-free polyurethane modified epoxy resin, halogen-free naphthalene epoxy resin, halogen-free silicone modified epoxy resin, halogen-free phosphorus-containing epoxy resin, toughening agent, flame retardant, curing agent, curing accelerator and organic solvent. In addition to the above components and impurities, it can also contain a small amount of other functional additives such as colorants.

[0046] In some examples, the halogen-free epoxy resin composition is composed of halogen-free bisphenol A epoxy resin, halogen-free polyurethane modified epoxy resin, halogen-free naphthalene epoxy resin, halogen-free silicone modified epoxy resin, halogen-free phosphorus-containing epoxy resin, toughening agent, flame retardant, curing agent, curing accelerator and organic solvent, and does not contain other substances except the above components and necessary impurities.

[0047] In some examples, in the halogen-free epoxy resin composition, the amount of the halogen-free bisphenol A epoxy resin is 10 parts, 11 parts, 12 parts, 13 parts, 14 parts, 15 parts, 16 parts, 17 parts, 18 parts, 19 parts, 20 parts, 21 parts, 22 parts, 23 parts, 24 parts or 25 parts; the amount of the halogen-free polyurethane modified epoxy resin is 0 parts, 11 parts, 12 parts, 13 parts, 14 parts, 15 parts, 16 parts, 17 parts, 18 parts, 19 parts, 20 parts, 21 parts, 22 parts, 23 parts , 24 parts or 25 parts, etc.; the amount of halogen-free naphthalene epoxy resin is 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, 11 parts, 12 parts, 13 parts, 14 parts, 15 parts, etc.; the amount of halogen-free silicone modified epoxy resin is 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, 11 parts, 12 parts, 13 parts, 14 parts, 15 parts, etc.; the amount of halogen-free phosphorus epoxy resin is 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, 11 parts, 12 parts, 13 parts, 14 parts, 15 parts The dosage of toughening agent is 15 parts, 16 parts, 17 parts, 18 parts, 19 parts, 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, 36 parts, 37 parts, 38 parts, 39 parts, 40 parts, etc.; the dosage of flame retardant is 15 parts, 16 parts, 17 parts, 18 parts, 19 parts, 20 parts, 21 parts, 22 parts, 23 parts, 24 parts, 25 parts, 26 parts, The amount of curing agent is 1 part, 2 parts, 3 parts, 4 parts, 5 parts, 5.1 parts, 5.2 parts, 5.3 parts, 5.4 parts, 5.5 parts, 5.6 parts, 5.7 parts, 5.8 parts, 5.9 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, etc.; the amount of curing accelerator is 0.01 part, 0.1 part, 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, etc.

[0048] In some examples, the modification method of the halogen-free polyurethane modified epoxy resin can be to synthesize a polyurethane prepolymer by polyhydroxy compounds and polyisocyanates, and then graft the prepolymer with epoxy resin to synthesize a halogen-free polyurethane modified epoxy resin; or to directly synthesize the halogen-free polyurethane modified epoxy resin by bulk synchronous polymerization; no matter which of the above methods is used to prepare the halogen-free polyurethane modified epoxy resin, as long as it can meet the performance requirements of use, it can be used in the formulation of the present invention.

[0049] By combining a halogen-free polyurethane-modified epoxy resin with a toughening agent and adjusting the formulation, the toughening effects of both can be fully utilized. Furthermore, due to the low molecular weight of the halogen-free polyurethane-modified epoxy resin, the crosslink density of the cured product can be increased, thereby enhancing the cohesive strength of the adhesive layer and, ultimately, the peel strength of the film. Currently commercially available halogen-free polyurethane-modified epoxy resins include HyPox UA 10 and HyPox UA 11 (manufactured by CVC Thermoset Specialty Materials, Inc., USA).

[0050] In some examples, the halogen-free naphthalene-based epoxy resin is an epoxy resin containing a naphthalene ring structure in its molecular structure.

[0051] In some examples, the halogen-free naphthalene-based epoxy resin is a compound comprising the following structure and its derivatives:

[0052]

[0053] .

[0054] Naphthalene-based epoxy resins contain both a heat-resistant naphthalene ring and multiple reactive groups within their molecules. They cure quickly, produce a high crosslink density, and exhibit low shrinkage, high Tg, and high strength. Any of these resins, as long as they meet the performance requirements, can be used in the formulations described herein.

[0055] In some examples, the halogen-free naphthalene epoxy resin includes NC-7000L (manufactured by Nippon Kayaku Co., Ltd.), HP-4710, HP-4032D (manufactured by DIC Corporation of Japan), and the like.

[0056] In some examples, halogen-free silicone-modified epoxy resins are prepared by introducing silicone into epoxy resins through either physical blending or chemical reaction. The chemical reaction primarily utilizes silicone terminal functional groups (such as alkoxy, amino, and hydroxyl groups) to react with epoxy groups in the epoxy resin to form core-shell, grafted, or block copolymers. These silicone-modified epoxy resins exhibit both high heat resistance and strong toughness. Compatibility is a key factor affecting the effectiveness of silicone-modified epoxy resins, and both methods mentioned above effectively overcome this issue. Furthermore, silicone-modified epoxy resins inherently exhibit excellent flame retardancy and can form a heat-resistant protective layer, making them environmentally friendly flame-retardant materials. Regardless of the method used to prepare the silicone-modified epoxy resin, as long as it meets the performance requirements, it can be used in the formulations described herein.

[0057] Introducing silicone-modified epoxy resins into formulations can enhance adhesive toughness and heat resistance, while also improving weather resistance, low-temperature resistance, and reducing surface energy. Currently commercially available halogen-free silicone-modified epoxy resins include ALBIDUR® EP 2240A and NANOPOX® A 410 (manufactured by Evonik Industries AG).

[0058] In some examples, a halogen-free phosphorus-containing epoxy resin is a flame-retardant epoxy resin synthesized by chemically bonding a reactive phosphorus compound to the epoxy resin molecular chain. The reactive phosphorus compound may include a phosphophananthenanthrene compound having a typical structure as shown below:

[0059]

[0060] 9,10-Dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) and its derivatives: 10-(2,5-dihydroxyphenyl)-10-hydro-9-oxa-10-phosphaphenanthrene-10-oxide. Other reactive organophosphorus and inorganic phosphorus compounds are also acceptable. Phosphorus-containing epoxy resins modified in any manner can be used in the formulations described herein, as long as they meet the performance requirements.

[0061] In some examples, the halogen-free phosphorus-containing epoxy resin has a phosphorus content of 0.5% to 16%.

[0062] In some examples, commercially available halogen-free phosphorus-containing epoxy resins include XEN-0140, SEN-6085 (Shinan SHIN-A T&C, South Korea), and the like.

[0063] 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. Commercially available nitrile rubber includes CTBN 1300×8 (manufactured by CVC Thermoset Specialty Materials, Inc., USA), styrene-butadiene rubber includes Buna VSL 5025-2 HM (manufactured by Lanxess), butadiene rubber includes BR-9000 (manufactured by Sinopec), ethylene-propylene rubber includes EPDM6950 (manufactured by Lanxess), polyolefin resin includes Affinity™ GA1950 (manufactured by Dow Chemical, USA), polyamide-imide resin includes Torlon® 4203L (manufactured by SOLVAY, USA), and polyurethane toughening agents and elastomers include Desmocap 11A (manufactured by Covestro).

[0064] In some examples, the flame retardant includes, but is not limited to, MARTINAL® ON-906, MAGNIFIN® H-5 IV (manufactured by JM Huber Corporation), PX-200 (manufactured by Daihachi Chemical Industry Co., Ltd., Japan), OP930 (manufactured by Clariant, Germany), and the like.

[0065] In some examples, the curing agent is one or more of linear phenolic resin curing agent, linear bisphenol A phenolic resin curing agent, linear o-cresol formaldehyde resin curing agent, 4,4'-diaminodiphenylmethane, m-phenylenediamine, and m-phenylenediamine. 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 includes ANCAMINE®DL-50 (manufactured by Evonik Industries AG), meta-phenylenediamine includes MPD (Jiangsu Shengbang New Materials Co., Ltd.), and meta-phenylenediamine MXDA (manufactured by Mitsubishi Gas Chemical Trading, Inc., Japan).

[0066] In some examples, the curing accelerator is one or more of a microcapsule curing agent, boron trifluoride, and / or imidazole or its derivatives having the following structure:

[0067] .

[0068] In some examples, commercially available microcapsule curing agents include HX-3722 and HX-3921HP (manufactured by ASAHI KASEICORPORATION, Japan), boron trifluoride includes 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).

[0069] In some examples, the organic solvent is 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, the halogen-free epoxy resin composition comprises the following components, calculated by weight, based on solid weight: 17-18 parts halogen-free bisphenol A epoxy resin; 10-13 parts halogen-free polyurethane-modified epoxy resin; 6-9 parts halogen-free naphthalene epoxy resin; 7-9 parts halogen-free organosilicon-modified epoxy resin; 6-7 parts halogen-free phosphorus-containing epoxy resin; 21-22 parts toughening agent; 20-22 parts flame retardant; 5-5.5 parts curing agent; 0.5-1 part curing accelerator; and an appropriate amount of organic solvent. When the amounts of each component are within the above ranges, the composition exhibits improved bonding properties, insulation properties, solder resistance, electrolyte resistance, and heat and humidity resistance.

[0071] In some examples, a low-temperature hot-pressed adhesive film is prepared from a halogen-free epoxy resin composition, which includes: a PET release film 1, a halogen-free epoxy resin composition layer 2 coated on the PET release film 1, and a PET protective film 3 attached to the halogen-free epoxy resin composition layer 2.

[0072] In some examples, the PET release film 1 is colorless and transparent, with a thickness of 3-100 μm; the halogen-free epoxy resin composition layer 2 is an opaque adhesive layer with a coating thickness of 3-100 μm; and the PET protective film 3 has a thickness of 3-100 μm.

[0073] 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, which is then applied to a PET release film 1 using a coating device. The PET release film 1 coated with the suspension slurry is passed through an oven and heated at 70-160°C for 2 to 6 minutes to dry, forming a layer of the composition in a solvent-free solid film state. The film is then applied with a PET protective film 3 at 50-90°C and 0.05-2.0 MPa, and rolled up to obtain the film.

[0074] In some examples, the suspension slurry is prepared by uniformly mixing the resin component, inorganic solid component, curing agent and organic solvent in the halogen-free epoxy resin composition using grinding equipment such as a sand mill and dispersing equipment such as a high-speed stirrer.

[0075] 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 the coating process.

[0076] This embodiment uses a halogen-free high-performance epoxy resin composition and is combined with a low-temperature latent curing agent to enable the adhesive to activate the reaction at low temperatures (80-120°C). This reduces the reaction temperature and meets low-temperature operation requirements while maintaining the original bonding, insulation and other properties. It passes the 300°C / 30s high-temperature impact test and has high reliability. On the other hand, the low-temperature hot-pressed adhesive film can also adapt to the production process of lithium batteries and meet the requirements of electrolyte resistance.

[0077] The present invention will be further described in detail below through specific examples.

[0078] Example 1

[0079] 18 parts by weight of a halogen-free bisphenol A epoxy resin (product model MY 790-1, epoxy equivalent weight 172 g / eq, manufactured by Huntsman, USA); 11 parts by weight of a halogen-free polyurethane-modified epoxy resin (product model HyPox UA 10, epoxy equivalent weight 215 g / eq, manufactured by CVC Thermosetting Specialty Materials, USA); 8 parts by weight of a halogen-free naphthalene-based epoxy resin (NC-7000L, epoxy equivalent weight 230 g / eq, manufactured by Nippon Kayaku Co., Ltd., Japan); 8 parts by weight of a halogen-free silicone-modified epoxy resin (ALBIDUR® EP 2240A, epoxy equivalent weight 308 g / eq, manufactured by Evonik Industries AG); and 8 parts by weight of a halogen-free phosphorus-containing epoxy resin (product model XEN-0140, epoxy equivalent weight 430 g / eq, manufactured by SHIN-A, South Korea). A halogen-free epoxy resin composition was prepared by adjusting the rotational viscosity of the adhesive solution to 500-2000 cps using solvents (methyl ethyl ketone and toluene). This composition was evenly coated on a 75μm thick PET film and baked in a 150°C oven for 4 minutes. The film was then laminated with a 50μm thick PET protective film using a hot roller and wound to form a film.

[0080] Example 2

[0081] 17 parts by weight of a halogen-free bisphenol A epoxy resin (product model MY 790-1, epoxy equivalent weight 172 g / eq, manufactured by Huntsman, USA); 13 parts by weight of a halogen-free polyurethane-modified epoxy resin (product model HyPox UA 10, epoxy equivalent weight 215 g / eq, manufactured by CVC Thermosetting Specialty Materials, USA); 6 parts by weight of a halogen-free naphthalene-based epoxy resin (HP-4710, epoxy equivalent weight 170 g / eq, manufactured by DIC, Japan); 8 parts by weight of a halogen-free silicone-modified epoxy resin (ALBIDUR® EP 2240A, epoxy equivalent weight 308 g / eq, manufactured by Evonik Industries AG); and 8 parts by weight of a halogen-free phosphorus-containing epoxy resin (product model XEN-0140, epoxy equivalent weight 430 g / eq, manufactured by SHIN-A, South Korea). A halogen-free epoxy resin composition was prepared by adjusting the rotational viscosity of the adhesive solution to 500-2000 cps using solvents (methyl ethyl ketone and toluene). This composition was evenly coated on a 75 μm thick PET film and then baked in a 150°C oven for 4 minutes. The film was then laminated with a 50 μm thick PET protective film using a hot roller and wound to form a film.

[0082] Example 3

[0083] 18 parts by weight of halogen-free bisphenol A epoxy resin (product model MY 790-1, epoxy equivalent 172 g / eq, manufactured by Huntsman, USA); 10 parts by weight of halogen-free polyurethane modified epoxy resin (product model HyPox UA 10, epoxy equivalent 215 g / eq, manufactured by CVC Thermosetting Specialty Materials, USA); 9 parts by weight of halogen-free naphthalene epoxy resin (HP-4032D, epoxy equivalent 143 g / eq, manufactured by DIC, Japan); 8 parts by weight of halogen-free silicone modified epoxy resin (ALBIDUR® EP 2240A, epoxy equivalent 308 g / eq, manufactured by Evonik Industries AG); 8 parts by weight of halogen-free phosphorus-containing epoxy resin (product model XEN-0140, epoxy equivalent 430 g / eq, manufactured by SHIN-A, South Korea). A halogen-free epoxy resin composition was prepared by adding 7 parts by weight of a propylene glycol (T&C) resin; 21 parts by weight of a toughening agent (Desmocap 11A, Covestro); 11 parts by weight of flame retardant 1 (OP930, Clariant, Germany); 10 parts by weight of flame retardant 2 (MAGNIFIN® H-5 IV, JM Huber Corporation, USA); 5.4 parts by weight of a linear o-cresol formaldehyde resin curing agent, KA-1160 (DIC, Japan); and 0.6 parts by weight of an imidazole or its derivative 1B2MZ (SHIKOKU CHEMICALSCORPORATION, Japan). The adhesive solution was adjusted to a rotational viscosity of 500-2000 cps using solvents (methyl ethyl ketone and toluene). This composition was evenly coated onto a 75 μm thick PET film and then baked in a 150°C oven for 4 minutes. The film was then laminated with a 50 μm thick PET protective film using a hot roller and wound up to form a film.

[0084] Example 4

[0085] 18 parts by weight of a halogen-free bisphenol A epoxy resin (product model MY 790-1, epoxy equivalent weight 172 g / eq, manufactured by Huntsman, USA); 11 parts by weight of a halogen-free polyurethane-modified epoxy resin (product model HyPox UA 10, epoxy equivalent weight 215 g / eq, manufactured by CVC Thermosetting Specialty Materials, USA); 8 parts by weight of a halogen-free naphthalene-based epoxy resin (NC-7000L, epoxy equivalent weight 230 g / eq, manufactured by Nippon Kayaku Co., Ltd., Japan); 8 parts by weight of a halogen-free silicone-modified epoxy resin (ALBIDUR® EP 2240A, epoxy equivalent weight 308 g / eq, manufactured by Evonik Industries AG); and 8 parts by weight of a halogen-free phosphorus-containing epoxy resin (product model XEN-0140, epoxy equivalent weight 430 g / eq, manufactured by SHIN-A, South Korea). A halogen-free epoxy resin composition was prepared by mixing 7 parts by weight of a 1% hydroxyethyl ester (T&C), 7 parts by weight of a toughening agent (Desmocap 11A, Covestro), 21 parts by weight of a flame retardant 1 (OP930, Clariant, Germany), 11 parts by weight of a flame retardant 2 (MARTINAL® ON-906, JM Huber Corporation, USA), 5.5 parts by weight of 4,4'-diaminodiphenylmethane (ANCAMINE® DL-50, Evonik Industries AG), and 0.5 parts by weight of an imidazole or its derivative (SIZ, Shikoku Chemicals Corporation, Japan). The adhesive solution was adjusted to a rotational viscosity of 500-2000 cps using solvents (methyl ethyl ketone and toluene). This composition was evenly coated onto a 75 μm thick PET film and then baked in a 150°C oven for 4 minutes. The film was then laminated with a 50 μm thick PET protective film using a hot roller and wound up to form a film.

[0086] Comparative Example 1

[0087] The base formula is calculated based on 100 parts by weight of solid content. Except for the curing agent and accelerator, the addition ratios of other components are the same as in Example 1. The curing agent and accelerator are replaced with dihydrogen diamine and N-(2-hydroxy-4-nitrobenzene)-N',N'-dimethylurea in equal amounts, respectively.

[0088] Comparative Example 2

[0089] The base formula is calculated based on 100 parts by weight of solid content. Except for the curing agent and accelerator, the addition ratios of other components are the same as those in Example 2. The curing agent and accelerator are replaced with dihydrogen diamine and N-(2-hydroxy-4-nitrobenzene)-N',N'-dimethylurea in equal amounts, respectively.

[0090] Comparative Example 3

[0091] The base formula is calculated based on 100 parts by weight of solid content. Except for the curing agent and accelerator, the addition ratios of other components are the same as those in Example 3. The curing agent and accelerator are replaced with dihydrogen diamine and N-(2-hydroxy-4-nitrobenzene)-N',N'-dimethylurea in equal amounts, respectively.

[0092] Comparative Example 4

[0093] The base formula is calculated based on 100 parts by weight of solid content. Except for the naphthalene-type epoxy resin, the addition ratios of other components are the same as those in Example 1. The naphthalene-type epoxy resin is replaced with an equal amount of ordinary epoxy resin E51.

[0094] Test results

[0095] The properties of the films obtained in the above examples and comparative examples were tested using the following test methods.

[0096] (1) Thickness: Tested in accordance with GB / T 7125-2014.

[0097] (2) Peel strength: Test the peel strength between the film and the copper foil according to IPC-TM-650 2.4.9 method.

[0098] (3) Surface resistance: Tested according to IPC-TM-650 2.5.17 method.

[0099] (4) Volume resistivity: Tested in accordance with IPC-TM-650 2.5.17 method.

[0100] (4) Solder resistance: Tested according to IPC-TM-650 2.4.13 method.

[0101] (5) Electrolyte resistance test: The film is laminated on a PP film on one side and on an aluminum foil on the other side at 50-100°C. After lamination, it is hot pressed and cured. After the test piece is cured, it is immersed in the electrolyte (the electrolyte is prepared in an anhydrous environment with LiPF6 and one or more of ethylene carbonate (EC), diethyl carbonate (DEC), dimethyl carbonate (DMC), and ethyl methyl carbonate (EMC)). It is placed in an environment of 85°C for 48 hours, and then the tape is removed. After cooling to room temperature, the peel strength is tested according to the IPC-TM-6502.4.9 method. At the same time, observe whether the electrolyte has impurities, whether the color changes, and whether it is clear and transparent.

[0102] (6) Moisture and heat resistance reliability: The adhesive film is laminated on the PI film on one side and on the copper foil on the other side at 50-100°C. After lamination, it is hot pressed and cured. After the test piece is cured, it is kept at 85°C / 85%RH for 500 hours. After being taken out and cooled to room temperature, the peel strength is tested according to IPC-TM-650 2.4.9 method.

[0103] Table 1 Examples of formulations of halogen-free epoxy resin compositions and properties of low-temperature hot-pressed adhesive films prepared therefrom

[0104]

[0105] Table 2 Comparative examples of halogen-free epoxy resin compositions and properties of low-temperature hot-pressed adhesive films prepared therefrom

[0106]

[0107] Test result description and principle explanation:

[0108] It can be seen from the measured results that the halogen-free epoxy resin composition of the present invention and the prepared low-temperature hot-pressed adhesive film can not only activate the reaction at a low temperature (110°C), thereby reducing the reaction temperature and meeting the low-temperature operation requirements, but also maintain the original bonding, insulation and other properties, pass the 300°C / 30s high-temperature impact test, and have high reliability; on the other hand, the low-temperature hot-pressed adhesive film can also adapt to the production process of lithium batteries and meet the requirements of electrolyte resistance.

[0109] The above embodiments do not impose any restrictions on the content of the composition of the present invention. Any slight modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention or the composition ingredients or content are still within the scope of the technical solution of the present invention.

Claims

1. A halogen-free epoxy resin composition, characterized in that Calculated by solid weight, it includes the following components in parts by weight: 10-25 parts of halogen-free bisphenol A epoxy resin; 10-25 parts of halogen-free polyurethane modified epoxy resin; 5-15 parts of halogen-free naphthalene epoxy resin; 5-15 parts of halogen-free silicone modified epoxy resin; 5-15 parts of halogen-free phosphorus-containing epoxy resin; 15-40 parts of toughening agent; 15-30 parts of halogen-free flame retardant; 1~10 parts of curing agent; 0.01~1 part of curing accelerator; Appropriate amount of organic solvent; The curing agent is at least one of linear phenolic resin curing agent, linear bisphenol A phenolic resin curing agent, linear o-cresol formaldehyde resin curing agent, 4,4'-diaminodiphenylmethane, metaphenylenediamine, and metaphenylenediamine.

2. A halogen-free epoxy resin composition according to claim 1, characterized in that: The curing accelerator is at least one of a microcapsule curing agent, boron trifluoride, imidazole or its derivatives having the following structure: 、 、 、 、 、 ； In the formula, R is selected from a hydrocarbon group, a substituted hydrocarbon group, a halogen, a nitro group, a carboxyl group, a hydroxyl group, an ester group, an ether bond, an aldehyde group, a ketone group or an amino group.

3. A halogen-free epoxy resin composition according to claim 1 or 2, characterized in that: The linear phenolic resin curing agent is selected from at least one of TD-2131 of DIC of Japan, KAYAHARD GPH-65 of Nippon Kayaku Co., Ltd. of Japan, KAYAHARD GPH-103 of Nippon Kayaku Co., Ltd. of Japan, and KAYAHARD KTG-105 of Nippon Kayaku Co., Ltd. of Japan; the linear bisphenol A type phenolic curing agent is selected from at least one of VH-4150 of DIC of Japan and KH-6021 of DIC of Japan; the linear o-cresol formaldehyde resin curing agent is selected from at least one of KA-1160 of DIC of Japan and KA-1165 of DIC of Japan; the 4,4'-diaminodiphenylmethane is selected from ANCAMINE® DL-50 of Evonik Industries AG; the m-phenylenediamine is selected from MPD of Jiangsu Shengbang New Materials Co., Ltd.; the m-phenylenediamine is selected from MXDA of Mitsubishi Gas Chemical Trading, Inc. of Japan; The curing agent accelerator is selected from at least one of microcapsule curing agent HX-3722 of ASAHI KASEI CORPORATION of Japan, microcapsule curing agent HX-3921HP of ASAHI KASEI CORPORATION of Japan, boron trifluoride OMICURE BC-120 of CVC Thermosetting Special Materials Company of the United States, imidazole or its derivative SIZ of SHIKOKU CHEMICALS CORPORATION of Japan, imidazole or its derivative 2MZ-H of SHIKOKU CHEMICALS CORPORATION of Japan, and imidazole or its derivative 1B2MZ of SHIKOKU CHEMICALSCORPORATION of Japan.

4. A halogen-free epoxy resin composition according to claim 1 or 2, characterized in that: The halogen-free polyurethane modified epoxy resin is synthesized by synthesizing a polyurethane prepolymer from a polyol and a polyisocyanate, and then grafting the polyurethane prepolymer with an epoxy resin to synthesize the halogen-free polyurethane modified epoxy resin, or synthesized by bulk synchronous polymerization. The halogen-free naphthalene epoxy resin comprises a compound represented by the following structural formula or a derivative thereof: 、 、 、 ； The halogen-free organosilicon-modified epoxy resin is a halogen-free organosilicon-modified epoxy resin obtained by physically blending an organosilicon compound and an epoxy resin, or the halogen-free organosilicon-modified epoxy resin is a copolymer having a core-shell structure, a graft structure, or a block structure obtained by reacting the active terminal functional groups of the organosilicon compound with the epoxy groups in the epoxy resin; The halogen-free phosphorus-containing epoxy resin is a flame-retardant epoxy resin obtained by chemically bonding a reactive phosphorus compound to an epoxy resin molecular chain. The reactive phosphorus compound is selected from the phosphinophenanthrene compound shown in the following structure: 、 、 ； The phosphorus content of the halogen-free phosphorus-containing epoxy resin is 0.5%-16%; 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; 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.

5. A halogen-free epoxy resin composition according to claim 1 or 2, characterized in that: The halogen-free polyurethane modified epoxy resin is selected from at least one of HyPox UA 10 and HyPox UA 11 of CVC Thermosetting Specialty Materials, Inc., USA; The halogen-free naphthalene epoxy resin is selected from at least one of NC-7000L of Nippon Kayaku Co., Ltd., HP-4710 of DIC Corporation of Japan, and HP-4032D of DIC Corporation of Japan; The halogen-free organosilicon-modified epoxy resin is selected from at least one of ALBIDUR® EP 2240A of Evonik Industries AG and NANOPOX® A 410 of Evonik Industries AG; The halogen-free phosphorus-containing epoxy resin is selected from at least one of XEN-0140 of SHIN-A T&C of South Korea and SEN-6085 of SHIN-A T&C of South Korea; The toughening agent is selected from at least one of CVC Thermosetting Specialty Materials' nitrile rubber CTBN 1300×8, Lanxess's styrene-butadiene rubber Buna VSL 5025-2 HM, Sinopec's butadiene rubber, Lanxess's ethylene-propylene rubber EPDM6950, DOW's polyolefin resin Affinity™ GA1950, SOLVAY's polyamide-imide resin Torlon® 4203L, and Covestro's polyurethane Desmocap11A. The halogen-free flame retardant is selected from at least one of MARTINAL® ON-906 of JM Huber Corporation, MAGNIFIN® H-5 IV of JM Huber Corporation, PX-200 of Daihachi Chemical Industry Co., Ltd. of Japan, and OP930 of Clariant of Germany.

6. The method for preparing a halogen-free epoxy resin composition according to any one of claims 1 to 5, characterized in that The method comprises dissolving and mixing the halogen-free bisphenol A epoxy resin, the halogen-free polyurethane modified epoxy resin, the halogen-free naphthalene epoxy resin, the halogen-free organosilicon modified epoxy resin, the halogen-free phosphorus-containing epoxy resin, the toughening agent, the halogen-free flame retardant, the curing agent and the curing accelerator through the organic solvent to form a suspension slurry.

7. The method for preparing a halogen-free epoxy resin composition according to claim 6, wherein The suspension slurry is dispersed by at least one of a sand mill and a high-speed mixer; the rotational viscosity of the suspension slurry is 500-2000 cps.

8. A low temperature hot pressing adhesive film, characterized in that The invention comprises a PET release film, a halogen-free epoxy resin composition layer coated on the PET release film, and a PET protective film attached to the halogen-free epoxy resin composition layer, wherein the halogen-free epoxy resin composition layer is made of a halogen-free epoxy resin composition according to any one of claims 1 to 5.

9. The method for preparing a low-temperature hot-pressed adhesive film according to claim 8, characterized in that: Using a coating device, coating the suspension slurry of the halogen-free epoxy resin composition onto the PET release film, passing the PET release film coated with the suspension slurry through an oven, heating the PET release film at 70-160° C. for 2-6 minutes to dry it, forming a layer of the composition in a solvent-free solid film state, then laminating it with a PET protective film at 50-90° C. and 0.05-2.0 MPa, and winding it to obtain the low-temperature hot-pressed adhesive film; The PET release film is colorless and transparent, with a thickness of 3 to 100 μm; the halogen-free epoxy resin composition layer is an opaque adhesive layer with a coating thickness of 3 to 100 μm; and the PET protective film has a thickness of 3 to 100 μm.

10. Application of a low temperature hot pressing adhesive film, characterized in that The low-temperature hot-pressed adhesive film is used to encapsulate and protect circuits on circuit boards, or to fix and protect components in the production process of lithium batteries; the low-temperature hot-pressed adhesive film is the low-temperature hot-pressed adhesive film described in claim 8 or the low-temperature hot-pressed adhesive film obtained by the preparation method described in claim 9.

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