Temperature-sensitive conductive packaging adhesive, preparation method thereof and temperature-sensitive conductive packaging adhesive film

Abstract

The invention belongs to the technical field of electronic packaging materials, and particularly relates to a temperature-sensitive conductive packaging adhesive, a preparation method thereof and a temperature-sensitive conductive packaging adhesive film. The thermo-sensitive conductive packaging adhesive is formed by mixing the sum of resins in a resin prepolymer and thermo-sensitive ceramic powder according to the mass ratio of 100: (30-85), and the resin prepolymer is formed by mixing matrix resin, reinforced resin, a diluent, a silane coupling agent and a flexibilizer according to the mass ratio of 100: (5-20): (5-100): (1-3): (1-5); wherein the matrix resin is epoxy resin, acrylic ester resin or polyurethane resin; the reinforced resin is at least one of organic silicon modified polyurethane and organic silicon modified polyimide. According to the invention, the safety problem of adhesive film aging or assembly spontaneous combustion caused by local hot spot and high temperature due to subfissure or shielding of the existing photovoltaic assembly is solved; and the problems of insufficient packaging effect of the conventional packaging adhesive at high temperature and poor durability caused by mismatching of thermal expansion coefficients of matrix resin and filler are solved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of electronic packaging materials, and particularly relates to a temperature-sensitive conductive packaging glue, a preparation method thereof and a temperature-sensitive conductive packaging glue film. BACKGROUND

[0002] Photovoltaic power generation has become the core technology for promoting the large-scale application of renewable energy due to its cost-effectiveness, and has been widely deployed in ground power stations, distributed systems and photovoltaic building integrated scenarios. The power density and conversion efficiency of current photovoltaic modules continue to improve, but the high-temperature hot spot problem caused by complex outdoor environments such as high temperature, shading, dust, etc. has become a key technical bottleneck restricting the safety and long-term reliability and operation economy of photovoltaic systems.

[0003] From the technical essence, photovoltaic modules achieve power output through cell piece series / parallel connection. When the local area causes current mismatch due to three core factors, i.e. a sudden drop in photo-generated current caused by external shading such as trees, bird droppings, dust, etc., two local performance degradation caused by inherent defects of the module such as cell hidden cracks, virtual welding of welding, aging of packaging materials, and three current imbalance aggravated by poor heat dissipation in the region under extreme high temperature such as summer ground over 60℃. In the mismatch state, the low-efficiency cell piece is converted into a "load", making the hot spot temperature reach 80℃-180℃, far exceeding the normal working interval of-40℃-85℃, forming a fire safety hazard.

[0004] The thermal spot hazard accumulates in a ladder form: short-term acceleration of EVA / POE glue film, backboard and other packaging materials, causing the light transmittance and power of the module to decrease; long-term causes the hidden cracks of the cell piece to expand, the solder strip to melt, and even triggers the safety accidents such as backboard burning and glass cracking, shortens the service life of the module to 10-15 years, and the annual power attenuation rate reaches 2%-5%, while the normal attenuation is only 0.5%-1%, causing significant industrial economic losses.

[0005] The existing technical system is divided into two categories: passive protection such as optimizing module layout, leakage sorting and inter-string diode, and active intervention such as infrared imaging monitoring, MPPT optimizer and automatic dust removal system, but there are fundamental limitations: passive technology only alleviates the harm and cannot eliminate current mismatch; active technology is high in cost such as optimizer accounting for 10%-15% of the cost of the module, and is susceptible to environmental interference in reliability, and is difficult to meet the application requirements of large-scale power stations. SUMMARY

[0006] In order to solve the safety problems of the aging of the glue film or the self-ignition of the photovoltaic module caused by the local hot spot high temperature due to the hidden cracks or the shielding of the existing photovoltaic module, the insufficient encapsulation effect of the existing conventional encapsulation glue at high temperature, and the poor durability caused by the mismatch of the thermal expansion coefficients of the matrix resin and the filler, the application provides a temperature-sensitive conductive encapsulation glue, a preparation method thereof and a temperature-sensitive conductive encapsulation glue film. A temperature-sensitive conductive epoxy, acrylic or polyurethane resin conductive glue and glue film are designed and developed, which can automatically conduct the local photovoltaic cell to rise in temperature under the shielding condition, avoid the self-ignition caused by the excessively high temperature, reduce the abnormal working safety hazards of the hot spot shielding, and the strong adhesion also solves the problems of the insufficient encapsulation effect of the existing conventional encapsulation glue at high temperature and the poor durability caused by the mismatch of the thermal expansion coefficients of the matrix resin and the filler.

[0007] The application solves the above technical problems through the following technical scheme.

[0008] The first object of the application is to provide a temperature-sensitive conductive encapsulation glue, which is formed by mixing a resin prepolymer and a temperature-sensitive ceramic powder, the resin prepolymer is formed by mixing a matrix resin, a reinforcing resin, a diluent, a silane coupling agent and a toughening agent, and the mass ratio of the matrix resin, the reinforcing resin, the diluent, the silane coupling agent and the toughening agent is 100:5-20:5-100:1-3:1-5; and the mass ratio of the sum of the resins in the resin prepolymer and the temperature-sensitive ceramic powder is 100:30-85.

[0009] The matrix resin is an epoxy resin, an acrylic ester resin or a polyurethane resin; when the matrix resin is an epoxy resin, a first curing agent and an accelerator are added for mixing and curing; when the matrix resin is a polyurethane resin, a second curing agent is added for mixing and curing; and when the matrix resin is an acrylic ester resin, a photoinitiator is added for curing.

[0010] The reinforcing resin is at least one of a silicone-modified polyurethane and a silicone-modified polyimide, and the temperature-sensitive ceramic powder is a temperature-sensitive ceramic with a negative temperature coefficient, and the negative temperature coefficient is-2% / ℃ to-10% / ℃.

[0011] In the present application, the present application takes high-temperature-resistant resins such as epoxy, acrylate and polyurethane as the base resin, takes silicone-modified polyurethane or / and silicone-modified polyimide as the reinforcing resin, and takes temperature-sensitive ceramics as the filler. Through curing, the active groups in the base resin undergo crosslinking reaction to form a dense spatial network structure, forming the conductive adhesive framework. At the same time, the reinforcing resin has a large number of active functional groups, which can chemically bond with the base resin, van der Waals force, mechanical occlusion and other effects, thereby improving the adhesion performance. The introduction of the silicone component effectively inhibits the degradation of the base resin at high temperature, which can further enhance the weather resistance and high-temperature resistance of the conductive adhesive, thereby enhancing the heat aging resistance of the material. In the curing process, the temperature-sensitive ceramic particles contact each other to form a stable structure of the connecting path. Through the temperature-sensitive properties of the temperature-sensitive ceramic component, the encapsulation adhesive realizes low-temperature insulation packaging. At high temperature, the abnormal working safety hazard caused by thermal spot shielding is reduced through conduction. Finally, the temperature-sensitive conductive encapsulation adhesive and adhesive film with sensitive temperature-sensitive conductivity, excellent adhesion strength and high-temperature resistance are obtained. In addition, combined with the synergistic effect of fillers such as diluents, coupling agents and toughening agents, the temperature-sensitive conductive encapsulation adhesive and adhesive film with sensitive temperature-sensitive conductivity, excellent adhesion strength and high-temperature resistance are finally obtained. Thus, the safety problem of the aging of the adhesive film or the self-ignition of the module caused by the local thermal spot high temperature due to the hidden cracks or shielding of the existing photovoltaic module is solved; and the problem of poor encapsulation effect of the existing conventional encapsulation adhesive at high temperature and the poor durability caused by the mismatch of the thermal expansion coefficient between the base resin and the filler is solved.

[0012] In the present application, the base resin is a high-temperature-resistant epoxy resin, an acrylate resin and a polyurethane resin, etc. Among them, the epoxy resin has a large number of polar functional groups such as epoxy and hydroxyl groups, and has high activity, which can chemically bond with the base material. In addition, the epoxy active group undergoes ring-opening curing reaction under the action of the curing agent, which provides strong adhesion performance and generates a three-dimensional network polymer, providing the overall framework of the conductive encapsulation adhesive and playing a decisive role in the mechanical properties of the temperature-sensitive conductive encapsulation adhesive. In addition, the structure of the epoxy resin is very stable, so the cured product has good solvent resistance, acid resistance and alkali resistance, etc. The acrylate resin has the characteristics of fast curing speed, high adhesion strength, good weather resistance, excellent temperature resistance and wide application range. The acrylate-based glue realizes the adhesion effect through the physical entanglement of the high molecular chain, the intermolecular force and the chemical bonding mechanism. Polyurethane is a high molecular material formed by polyol and polyisocyanate through condensation reaction and has excellent mechanical properties. The polyisocyanate molecular chain contains isocyanide-NCO and carbamate-NH-COO-, so the polyurethane adhesive shows high activity and polarity. The isocyanate groups in the system react with substances containing active hydrogen inside or outside the system to generate polyurethane groups or polyurea, thereby greatly improving the system strength and achieving the purpose of adhesion.

[0013] In some embodiments, the temperature-sensitive ceramic with a negative temperature coefficient is at least one selected from MnO-CuO-O2, MnO-CoO-O2, MnO-NiO-O2, Mn-Co-Ni oxide, Mn-Cu-N, Mn-Cu-Co oxide, and Sb- and P-doped SnO2 ceramic powders. In this invention, the temperature-sensitive ceramic with a negative temperature coefficient is a type of functional ceramic material whose resistance decreases with increasing temperature. Introducing it into conductive adhesives enables the adhesive to function normally (e.g., non-conductive at low temperatures) but conduct and short-circuit under abnormal hot spot conditions (e.g., high temperatures), preventing film aging or spontaneous combustion.

[0014] In some embodiments, the epoxy resin is at least one selected from bisphenol A type epoxy resin, phenolic epoxy resin, and naphthyl ring type epoxy resin. When the matrix resin is an epoxy resin, the mass ratio of the first curing agent to the matrix resin is 0.2 to 1.2:1, the amount of accelerator is 1% to 5% of the mass of the matrix resin, the first curing agent is at least one selected from aliphatic curing agents, acid anhydride curing agents, and imidazole curing agents, and the accelerator is at least one selected from phenol, dodecylamine, and n-butanol. In a preferred embodiment, the first curing agent is at least one selected from triethanolamine, dicyandiamide, 4,4'-diaminodiphenyl sulfone, methylhexahydrophthalic anhydride, and 3,3',4,4'-benzophenone tetracarboxylic dianhydride.

[0015] In this invention, the epoxy resin contains a large number of polar functional groups such as epoxy groups and hydroxyl groups, which are highly active and can form chemical bonds with the matrix material. The first curing agent and the accelerator promote the ring opening of the epoxy functional groups of the epoxy resin, further promoting the cross-linking of the molecular chain, so that the epoxy resin forms a stable three-dimensional network structure, improves the adhesion, and forms an epoxy resin-based conductive encapsulant.

[0016] In some embodiments, the main agent of the polyurethane resin is at least one of polypropylene glycol, polypropylene triol, and polytetrahydrofuran. When the matrix resin is a polyurethane resin, the mass ratio of the second curing agent to the matrix resin is 0.2 to 0.5:1, and the second curing agent is at least one of toluene diisocyanate, diphenylmethane diisocyanate, naphthalene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, and 1,4-cyclohexane diisocyanate-based curing agents.

[0017] In this invention, polyurethane resin is a polymer material with excellent mechanical properties formed by polycondensation reaction of polyols and polyisocyanates. A second curing agent is used to react isocyanate groups with substances containing active hydrogen inside or outside the system to generate polyurethane groups or polyurea, thereby greatly improving the strength of the system and achieving the purpose of adhesion, thus forming a polyurethane-based conductive encapsulant.

[0018] In some embodiments, the acrylate resin is at least one of polyurethane acrylate, epoxy acrylate, silicone-modified acrylate resin. When the base resin is acrylate resin, the amount of photoinitiator is 1% to 5% of the mass of the base resin, and the photoinitiator is at least one of 2-hydroxy-2-methyl-1-phenylpropanone, 1-hydroxycyclohexyl phenyl ketone, benzoin ethyl ether.

[0019] In the present application, the acrylate resin realizes the bonding effect through the physical entanglement of the high molecular chain, the intermolecular force and the chemical bonding mechanism, and based on the active free radicals or cations generated by the ultraviolet excitation of the photoinitiator, the monomer polymerization, crosslinking and branching reaction are triggered, the liquid glue is rapidly cured in seconds to minutes, and the acrylate-based conductive packaging glue is formed.

[0020] In some embodiments, when the base resin is an epoxy resin, the amount of diluent is 5% to 20% of the mass of the base resin, and the diluent is at least one of methyl glycol ether, butyl glycidyl ether, 1,4-butanediol diglycidyl ether or neopentyl glycol diglycidyl ether; when the base resin is an acrylate resin, the amount of diluent is 5% to 40% of the mass of the base resin, and the diluent is at least one of 1,6-hexanediol diacrylate, isobornyl acrylate, hydroxyethyl methacrylate and tetrahydrofurfuryl acrylate; when the base resin is a polyurethane resin, the amount of diluent is 5% to 100% of the mass of the base resin, and the diluent is at least one of acetone and ethyl acetate.

[0021] In some embodiments, the silane coupling agent is at least one of KH-550 or KH-560, and the toughening agent is at least one of phthalate and fumed silica.

[0022] In the present application, when the base resin is an epoxy resin, the diluent can reduce the viscosity of the slurry, better blend the ceramic filler and the resin, and the epoxy functional group can further open ring curing to improve the bonding performance; when the base resin is an acrylate resin, the diluent can polymerize and crosslink under the irradiation of the photoinitiator, thereby improving the performance of the packaging glue; when the base resin is a polyurethane resin, the diluent can reduce the viscosity of the slurry, better blend the ceramic filler and the resin. The coupling agent can disperse the ceramic filler, increase the bonding between the filler and the resin, improve the mechanical properties of the conductive adhesive, and also enhance the bonding between the adhesive and the substrate; the accelerator can accelerate the curing reaction and improve the production efficiency; the toughening agent can increase the impact strength; and the defoaming agent can reduce the bubbles in the glue, enhance the bonding and high temperature resistance.

[0023] The second object of the present application is to provide a preparation method of the above-mentioned temperature-sensitive conductive packaging glue, comprising the following steps: S1, mixing the base resin, the reinforcing resin, the diluent, the silane coupling agent and the toughening agent to form a resin prepolymer.

[0024] S2, adding the temperature-sensitive ceramic powder to the resin prepolymer, uniformly dispersing, then adding the first curing agent and the accelerator, or adding the second curing agent, or adding the photoinitiator, uniformly dispersing, then defoaming and grinding to obtain the temperature-sensitive conductive packaging glue.

[0025] In some embodiments, when the base resin is a polyurethane resin, it is necessary to mix the base resin, the reinforcing resin, the diluent, the silane coupling agent and the toughening agent under the atmosphere of a protective gas such as nitrogen to form a resin prepolymer.

[0026] In some embodiments, the temperature-sensitive conductive packaging glue can be cured and formed by program temperature control or ultraviolet light irradiation. When the base resin is an epoxy resin, it is first pre-cured at 50-100℃ for 1-2h, then cured at 120-150℃ for 2-3h, and finally cured at 180℃ for 1-3h. When the base resin is a polyurethane resin, it is first pre-cured at 50-80℃ for 1-2h, then cured at 100-150℃ for 1-3h. When the base resin is an acrylate resin, it is subjected to ultraviolet light curing, the wavelength of the ultraviolet light is 365nm, and the curing time is 1-30s.

[0027] In the present application, the temperature-sensitive conductive packaging glue is cured and formed by program temperature control or ultraviolet light irradiation, which realizes the full curing of the resin matrix and the close contact between the resin and the ceramic particles, and improves the stability and reliability of the conductive path at high temperature. Figure 1 As shown in the figure, the selected conductive filler is a temperature-sensitive ceramic with negative temperature coefficient, so that the resistance value of the conductive packaging glue decreases with the increase of temperature, which can realize the non-conduction of the conductive adhesive at low temperature <60℃ and the conduction of current at high temperature ≥60℃, avoiding the safety hazard of abnormal shielding of the packaging glue at high temperature, and reducing the working safety. The preparation process and raw material combination provided by the present application have good scalability and process compatibility, and can adapt to the needs of different use scenarios by adjusting the resin system, filler ratio and curing parameters, and have industrial application prospect. The temperature-sensitive conductive packaging glue prepared has outstanding performance in bonding strength, temperature-sensitive conductivity and high-temperature aging performance retention rate, and provides a key material support for high-reliability and high-safety electronic packaging.

[0028] In some embodiments, the vacuum degree of the vacuum degassing stirring is-0.095 to-0.1MPa, and the stirring time is 5-30min; the grinding frequency of the three-roll mill is 3-5 times.

[0029] In some embodiments, after the temperature-sensitive ceramic powder is added to the resin prepolymer and uniformly dispersed, a defoaming agent can be added to reduce the bubbles in the temperature-sensitive conductive packaging adhesive, the amount of the defoaming agent added is 0.5% to 2% of the mass of the base resin, and the defoaming agent is tributyl phosphate.

[0030] A third object of the present application is to provide a temperature-sensitive conductive packaging adhesive film, which is prepared by the method as described above. Figure 2 As shown in the formula, the temperature-sensitive conductive packaging adhesive is cast onto the adhesive film carrier, and is cured to obtain the temperature-sensitive conductive packaging adhesive film, the thickness of the temperature-sensitive conductive packaging adhesive film is 10 μm to 500 μm.

[0031] In the present application, when the temperature-sensitive conductive packaging adhesive is cast onto the adhesive film carrier, the temperature and flow speed need to be adjusted to ensure the uniformity of the film thickness, when the base resin is an epoxy resin, it is first pre-cured at 50°C to 100°C for 1 h to 2 h, then cured at 120°C to 150°C for 2 h to 3 h, and finally cured at 180°C for 1 h to 3 h; when the base resin is a polyurethane resin, it is first pre-cured at 50°C to 80°C for 1 h to 2 h, then cured at 100°C to 150°C for 1 h to 3 h; when the base resin is an acrylate resin, it is subjected to ultraviolet light curing, the wavelength of the ultraviolet light is 365 nm, and the curing time is 1 s to 30 s.

[0032] In some embodiments, the adhesive film carrier is EVA vinyl acetate and ethylene copolymer, POE-butene and octene copolymer, polyethylene or polypropylene.

[0033] Compared with the prior art, the present application has the following beneficial effects: The present application uses high-temperature-resistant resins such as epoxy, acrylate and polyurethane as the base resin, uses silicone-modified resin as the reinforcing resin, and adds temperature-sensitive ceramic fillers, and finally obtains a temperature-sensitive conductive packaging adhesive and film with sensitive temperature-sensitive conductivity, excellent adhesive strength and high-temperature resistance. Through the mechanism of program-controlled temperature or ultraviolet rapid curing, the active groups in the resin matrix undergo crosslinking reaction to form a dense spatial network structure, providing the overall framework for the conductive adhesive; in addition, the resin has a large number of active functional groups, which can form chemical bond, van der Waals force, mechanical bite and other effects with the base material, improving the adhesive performance. The introduction of the silicone component effectively inhibits the degradation of the base resin at high temperature, and enhances the heat aging resistance of the material. During the curing process, the temperature is controlled to promote the mutual contact between the temperature-sensitive ceramic particles to form a stable structure of the connecting path; through the temperature-sensitive characteristics of the temperature-sensitive ceramic component, the packaging adhesive realizes low-temperature insulation packaging, and at high temperature, the abnormal working safety hazard caused by the heat spot shielding is reduced through conduction. In addition, the synergistic effect of the fillers such as diluents, coupling agents and toughening agents is combined, and finally a temperature-sensitive conductive packaging adhesive and film with sensitive temperature-sensitive conductivity, excellent adhesive strength and high-temperature resistance are obtained.

[0034] The present application realizes sufficient curing of the resin matrix and close contact between the resin and the ceramic particles by an optimized stepwise curing process and ultraviolet light rapid curing process, and improves the stability and reliability of the conductive path at high temperature. The selected conductive filler is a temperature-sensitive ceramic with a negative temperature coefficient, so that the resistance value of the adhesive decreases with the increase of temperature, and the conductive adhesive can realize non-conduction at low temperature and conduction of current at high temperature in normal working condition, avoiding the safety hazard of abnormal shielding of hot spots of the packaging adhesive at high temperature, and reducing the working safety. The present application truly solves the film aging or spontaneous combustion of the existing packaging adhesive when hot spots appear at high temperature; and also solves the problems of performance attenuation, interface delamination and short service life of the existing conductive packaging adhesive in high temperature process.

[0035] The preparation process and raw material combination provided by the present application have good scalability and process compatibility, and can adapt to the needs of different use scenarios by adjusting the resin system, filler ratio and curing parameters, and have industrial application prospects. The temperature-sensitive conductive packaging adhesive prepared has outstanding performance in bonding strength, temperature-sensitive conductivity, high-temperature aging performance retention rate and the like, and provides a key material support for high-reliability and high-safety electronic packaging. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1 Figure 1 is a diagram of the fixed forming mechanism of the temperature-sensitive conductive packaging adhesive film of the present application.

[0037] Figure 2 Figure 1 is a diagram of the fixed forming mechanism of the temperature-sensitive conductive packaging adhesive film of the present application.

[0038] Figure 3 Figure 2 is a morphology structure diagram of the temperature-sensitive conductive packaging adhesive film prepared in Example 1 and Example 5, Figure 3 Figure 2 is a morphology structure diagram of the temperature-sensitive conductive packaging adhesive film prepared in Example 1 and Example 5, DETAILED DESCRIPTION

[0039] The technical solutions in the embodiments of the present application will be described clearly and completely in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0040] It should be noted that the professional terms used in the present application are only for the purpose of describing the specific embodiments, and are not intended to limit the protection scope of the present application. Unless otherwise specified, the various raw materials, reagents, instruments and equipment used in the following embodiments of the present application can be purchased from the market or prepared by the existing method.

[0041] The following is further illustrated by specific examples. Among them, the temperature sensitive ceramic powder can be purchased through commercial channels; the temperature sensitive ceramic powder used is self-made and commercially purchased, and the particle size is ≤5 μm. In each of the following examples, the main materials used are abbreviated as follows: bisphenol A type epoxy resin, abbreviated as EP; silicone modified polyimide, abbreviated as SI-PI; silicone modified polyurethane, abbreviated as SI-PUA; 4,4'-diamino diphenyl sulfone, abbreviated as DDS; 2-ethyl-4-methyl imidazole, abbreviated as EMI; temperature sensitive ceramic powder, abbreviated as NTC; epoxy diluent, abbreviated as ERD; γ-aminopropyl triethoxysilane, abbreviated as KH-550; γ-glycidyl ether propyl trimethoxysilane, abbreviated as KH-560; toughening agent, abbreviated as TA.

[0042] Example 1 A preparation method of a temperature sensitive conductive packaging adhesive film, comprising the following steps: S1, preparation of an epoxy resin prepolymer: 10 g of EP was added to a sample bottle, followed by 1.5 g of silicone modified polyurethane, 1.0 g of 1,4-butanediol diglycidyl ether as a diluent, and stirring for 10 min to mix uniformly. Then 0.5 g of silane coupling agent KH-560 and 0.2 g of toughening agent phthalate were added, and after continuing to stir for 10 min, the sample bottle was placed in a vacuum degassing stirrer and degassed at -0.1 MPa for 5 min to obtain a uniform epoxy resin prepolymer solution.

[0043] S2, preparation of a temperature sensitive conductive packaging adhesive: the temperature sensitive ceramic filler was added to the epoxy resin matrix solution obtained in S1, and the total mass of the ceramic filler was 70% of the solid mass of the resin. After preliminary mixing for 5 min, vacuum degassing stirring was carried out for 5 min. Then 5.0 g of 4,4'-diamino diphenyl sulfone as a curing agent and 0.1 g of 2-ethyl-4-methyl imidazole as an accelerator were added in proportion. Then the mixture was transferred to a three-roll mill and ground for 4 times to obtain a temperature sensitive conductive packaging adhesive.

[0044] S3, curing and forming of the temperature sensitive conductive packaging adhesive and preparation of the adhesive film: the temperature sensitive conductive packaging adhesive obtained in S2 was coated on an EVA substrate and placed in an 80°C oven for 1 h of pre-curing, then the temperature was gradually increased to 150°C for 2 h of curing, and finally post-cured at 180°C for 1 h, the forming was completed, and a temperature sensitive conductive packaging adhesive film was obtained, the thickness of the temperature sensitive conductive packaging adhesive film was 100 μm.

[0045] Example 2 A preparation method of a temperature sensitive conductive packaging adhesive film, which is different from example 1 in that a phenolic epoxy resin is selected as the matrix, comprising the following steps: S1, Preparation of epoxy resin prepolymer: 10 g of phenolic epoxy resin was added to a sample bottle, followed by 1.5 g of silicone-modified polyurethane, 1.0 g of 1,4-butanediol diglycidyl ether as a diluent, and stirring for 10 min to mix them uniformly. Then 0.5 g of silane coupling agent KH-560 and 0.2 g of toughening agent phthalate were added, and after continuing to stir for 10 min, the sample bottle was placed in a vacuum degassing stirrer and degassed at -0.1 MPa for 5 min to obtain a uniform epoxy resin prepolymer solution.

[0046] S2, Preparation of temperature-sensitive conductive packaging adhesive: The temperature-sensitive ceramic powder filler was added to the epoxy resin matrix solution obtained in S1, and the total mass of the ceramic filler was 70% of the solid mass of the resin. After preliminary mixing by stirring for 5 min, vacuum degassing stirring was performed for 5 min. Then 5.0 g of 4,4'-diaminodiphenyl sulfone was added as a curing agent and 0.1 g of 2-ethyl-4-methylimidazole was added as an accelerator. Then the mixture was transferred to a three-roll mill and ground 4 times to obtain a temperature-sensitive conductive packaging adhesive.

[0047] S3, Curing and molding of temperature-sensitive conductive packaging adhesive and preparation of adhesive film: The temperature-sensitive conductive adhesive obtained in S2 was coated on an EVA substrate and placed in an 80°C oven for 1 h of pre-curing, then the temperature was gradually increased to 150°C for 2 h of curing, and finally post-cured at 180°C for 1 h. The molding was completed to obtain a temperature-sensitive conductive packaging adhesive film with a thickness of 100 μm.

[0048] Example 3 A method for preparing a temperature-sensitive conductive packaging adhesive film, which is different from Example 1 in that silicone-modified polyimide is used as a reinforcing resin, comprising the following steps: S1, Preparation of epoxy resin prepolymer: 10 g of EP was added to a sample bottle, followed by 1.5 g of silicone-modified polyimide, 1.0 g of 1,4-butanediol diglycidyl ether as a diluent, and stirring for 10 min to mix them uniformly. Then 0.5 g of silane coupling agent KH-560 and 0.2 g of toughening agent phthalate were added, and after continuing to stir for 10 min, the sample bottle was placed in a vacuum degassing stirrer and degassed at -0.1 MPa for 5 min to obtain a uniform epoxy resin prepolymer solution.

[0049] S2, Preparation of the temperature-sensitive conductive encapsulation adhesive: The temperature-sensitive ceramic powder filler was added to the epoxy resin matrix solution obtained in S1, and the total mass of the ceramic filler was 70% of the mass of the resin solids. After initial mixing for 5 min, vacuum degassing and stirring were performed for 5 min. Then, 5.0 g of 4,4'-diaminodiphenyl sulfone was added as a curing agent and 0.1 g of 2-ethyl-4-methylimidazole was added as an accelerator. Then the mixture was transferred to a three-roll mill, ground for 4 times, and fully dispersed to obtain the temperature-sensitive conductive encapsulation adhesive.

[0050] S3, Curing and molding of the temperature-sensitive conductive encapsulation adhesive and preparation of the adhesive film: The temperature-sensitive conductive adhesive obtained in S2 was coated on the EVA substrate, pre-cured in an 80°C oven for 1 h, then the temperature was gradually increased to 150°C for curing for 2 h, and finally post-cured at 180°C for 1 h. The molding was completed to obtain the temperature-sensitive conductive encapsulation adhesive film, and the thickness of the temperature-sensitive conductive encapsulation adhesive film was 100 μm.

[0051] Example 4 A method for preparing a temperature-sensitive conductive encapsulation adhesive film, which is different from Example 1 in that methylhexahydrophthalic anhydride is used as a curing agent, comprising the following steps: S1, Preparation of an epoxy resin prepolymer: In a sample bottle, 10 g of EP was added, followed by 1.5 g of silicone-modified polyurethane, 1.0 g of 1,4-butanediol diglycidyl ether as a diluent, and stirring for 10 min to mix them uniformly. Then, 0.5 g of silane coupling agent KH-560 and 0.2 g of toughening agent phthalate were added, and stirring was continued for 10 min. Then, the sample bottle was placed in a vacuum degassing stirrer and degassed at -0.1 MPa for 5 min to obtain a uniform epoxy resin prepolymer solution.

[0052] S2, Preparation of the temperature-sensitive conductive encapsulation adhesive: The temperature-sensitive ceramic powder filler was added to the epoxy resin matrix solution obtained in S1, and the total mass of the ceramic filler was 70% of the mass of the resin solids. After initial mixing for 5 min, vacuum degassing and stirring were performed for 5 min. Then, 5.0 g of 4,4'-diaminodiphenyl sulfone was added as a curing agent and 0.1 g of 2-ethyl-4-methylimidazole was added as an accelerator. Then the mixture was transferred to a three-roll mill, ground for 4 times, and fully dispersed to obtain the temperature-sensitive conductive encapsulation adhesive.

[0053] S3, Curing and molding of the temperature-sensitive conductive encapsulation adhesive and preparation of the adhesive film: The temperature-sensitive conductive adhesive obtained in S2 was coated on the EVA substrate, pre-cured in an 80°C oven for 1 h, then the temperature was gradually increased to 150°C for curing for 2 h, and finally post-cured at 180°C for 1 h. The molding was completed to obtain the temperature-sensitive conductive encapsulation adhesive film, and the thickness of the temperature-sensitive conductive encapsulation adhesive film was 100 μm.

[0054] Example 5 A preparation method of a temperature-sensitive conductive packaging adhesive film, which is different from example 1 in that the addition amount of temperature-sensitive ceramic is 30% of the solid mass of the resin, comprising the following steps: S1, preparation of an epoxy resin prepolymer: 10 g of EP was added to a sample bottle, followed by 1.5 g of silicone-modified polyurethane, 1.0 g of 1,4-butanediol diglycidyl ether as a diluent, and stirring for 10 min to mix them evenly. Then 0.5 g of silane coupling agent KH-560 and 0.2 g of toughening agent phthalate were added, and after continuing to stir for 10 min, the sample bottle was placed in a vacuum degassing stirrer and degassed at -0.1 MPa for 5 min to obtain a uniform epoxy resin prepolymer solution.

[0055] S2, preparation of a temperature-sensitive conductive packaging adhesive: temperature-sensitive ceramic filler was added to the epoxy resin matrix solution obtained in S1, and the total mass of the ceramic filler was 30% of the solid mass of the resin. After preliminary mixing for 5 min, vacuum degassing stirring was carried out for 5 min. Then 5.0 g of 4,4'-diamino diphenyl sulfone was added as a curing agent and 0.1 g of 2-ethyl-4-methyl imidazole was added as an accelerator. Then the mixture was transferred to a three-roll mill and ground for 4 times to obtain a temperature-sensitive conductive packaging adhesive.

[0056] S3, curing and forming of the temperature-sensitive conductive packaging adhesive and preparation of the adhesive film: the temperature-sensitive conductive adhesive obtained in S2 was coated on an EVA substrate and placed in an 80°C oven for 1 h of pre-curing, then the temperature was gradually increased to 150°C for 2 h of curing, and finally post-cured at 180°C for 1 h. The forming was completed to obtain a temperature-sensitive conductive packaging adhesive film with a thickness of 100 μm.

[0057] Example 6 A preparation method of a temperature-sensitive conductive packaging adhesive film, which is different from example 1 in that the addition amount of temperature-sensitive ceramic is 30% of the solid mass of the resin, comprising the following steps: S1, preparation of an epoxy resin prepolymer: 10 g of EP was added to a sample bottle, followed by 1.5 g of silicone-modified polyurethane, 1.0 g of 1,4-butanediol diglycidyl ether as a diluent, and stirring for 10 min to mix them evenly. Then 0.5 g of silane coupling agent KH-560 and 0.2 g of toughening agent phthalate were added, and after continuing to stir for 10 min, the sample bottle was placed in a vacuum degassing stirrer and degassed at -0.1 MPa for 5 min to obtain a uniform epoxy resin prepolymer solution.

[0058] S2, Preparation of the temperature-sensitive conductive encapsulation adhesive: The temperature-sensitive ceramic powder filler was added to the epoxy resin matrix solution obtained in S1, and the total mass of the ceramic filler was 50% of the mass of the resin solids. After initial mixing for 5 min, vacuum degassing was performed for 5 min. Then, 5.0 g of 4,4'-diaminodiphenyl sulfone was added as a curing agent and 0.1 g of 2-ethyl-4-methylimidazole was added as an accelerator. Then the mixture was transferred to a three-roll mill and ground for 4 times to obtain a temperature-sensitive conductive encapsulation adhesive.

[0059] S3, Curing and molding of the temperature-sensitive conductive encapsulation adhesive and preparation of the adhesive film: The temperature-sensitive conductive adhesive obtained in S2 was coated on the EVA substrate, and pre-cured in an 80°C oven for 1 h, then the temperature was increased to 150°C for curing for 2 h, and finally post-cured at 180°C for 1 h. The molding was completed to obtain a temperature-sensitive conductive encapsulation adhesive film, and the thickness of the temperature-sensitive conductive encapsulation adhesive film was 100 μm.

[0060] Example 7 A method for preparing a temperature-sensitive conductive encapsulation adhesive film, which is different from Example 1 in that the amount of temperature-sensitive ceramic added is 80% of the mass of the resin solids, comprising the following steps: S1, Preparation of an epoxy resin prepolymer: In a sample bottle, 10 g of EP was added, followed by 1.5 g of silicone-modified polyurethane, 1.0 g of 1,4-butanediol diglycidyl ether as a diluent, and stirring for 10 min to mix them uniformly. Then 0.5 g of silane coupling agent KH-560 and 0.2 g of toughening agent phthalate were added, and after stirring for 10 min, the sample bottle was placed in a vacuum degassing stirrer and degassed at -0.1 MPa for 5 min to obtain a uniform epoxy resin prepolymer solution.

[0061] S2, Preparation of the temperature-sensitive conductive encapsulation adhesive: The temperature-sensitive ceramic powder filler was added to the epoxy resin matrix solution obtained in S1, and the total mass of the ceramic filler was 50% of the mass of the resin solids. After initial mixing for 5 min, vacuum degassing was performed for 5 min. Then, 5.0 g of 4,4'-diaminodiphenyl sulfone was added as a curing agent and 0.1 g of 2-ethyl-4-methylimidazole was added as an accelerator. Then the mixture was transferred to a three-roll mill and ground for 4 times to obtain a temperature-sensitive conductive encapsulation adhesive.

[0062] S3, Curing and molding of the temperature-sensitive conductive encapsulation adhesive and preparation of the adhesive film: The temperature-sensitive conductive adhesive obtained in S2 was coated on the EVA substrate, and pre-cured in an 80°C oven for 1 h, then the temperature was increased to 150°C for curing for 2 h, and finally post-cured at 180°C for 1 h. The molding was completed to obtain a temperature-sensitive conductive encapsulation adhesive film, and the thickness of the temperature-sensitive conductive encapsulation adhesive film was 100 μm.

[0063] Example 8 A preparation method of a temperature-sensitive conductive packaging adhesive film, which is different from example 1 in that a polyurethane resin is selected as a matrix, comprising the following steps: S1, preparation of polyurethane resin prepolymer: under nitrogen gas atmosphere, 10 g of polytetrahydrofuran is added to a sample bottle, followed by adding 1.5 g of silicone-modified polyurethane, 1.0 g of acetone as a diluent, and stirring for 10 min to mix them uniformly. Then 0.5 g of silane coupling agent KH-560 and 0.2 g of toughening agent phthalate are added, and after continuing to stir for 10 min, the sample bottle is placed in a vacuum degassing stirrer, and degassing stirring is carried out at -0.1 MPa for 5 min to obtain a uniform polyurethane resin prepolymer solution.

[0064] S2, preparation of temperature-sensitive conductive packaging adhesive: the temperature-sensitive ceramic powder filler is added to the polyurethane resin prepolymer solution obtained in S1, and the total mass of the ceramic filler is 70% of the solid mass of the resin. After preliminary mixing for 5 min, vacuum degassing stirring is carried out for 5 min. Then 5.0 g of hexamethylene diisocyanate is added as a curing agent in proportion. Then the mixture is transferred to a three-roll mill, and after grinding for 4 times, a temperature-sensitive conductive packaging adhesive is obtained.

[0065] S3, curing and forming of the temperature-sensitive conductive packaging adhesive and preparation of the adhesive film: the temperature-sensitive conductive packaging adhesive obtained in S2 is coated on an EVA substrate, and placed in a 60°C oven for pre-curing for 1 h, and then the temperature is gradually increased to 120°C for curing for 2 h, and the forming is completed to obtain a temperature-sensitive conductive packaging adhesive film. The thickness of the temperature-sensitive conductive packaging adhesive film is 100 μm.

[0066] Example 9 A preparation method of a temperature-sensitive conductive packaging adhesive film, which is different from example 1 in that an acrylate resin is selected as a matrix, comprising the following steps: S1, preparation of polyurethane resin prepolymer: under nitrogen gas atmosphere, 10 g of polytetrahydrofuran is added to a sample bottle, followed by adding 1.5 g of silicone-modified polyurethane, 1.0 g of acetone as a diluent, and stirring for 10 min to mix them uniformly. Then 0.5 g of silane coupling agent KH-560 and 0.2 g of toughening agent phthalate are added, and after continuing to stir for 10 min, the sample bottle is placed in a vacuum degassing stirrer, and degassing stirring is carried out at -0.1 MPa for 5 min to obtain a uniform polyurethane resin prepolymer solution.

[0067] S2, Preparation of the temperature-sensitive conductive encapsulation adhesive: The temperature-sensitive ceramic powder filler was added to the acrylate resin prepolymer solution obtained in S1, and the total mass of the ceramic filler was 70% of the mass of the resin solids. After initial mixing for 5 min, vacuum degassing was performed for 5 min. Then, 0.3 g of 1-hydroxycyclohexyl phenyl ketone was added as a photoinitiator. Then, the mixture was transferred to a three-roll mill, and grinding was performed four times to obtain a temperature-sensitive conductive encapsulation adhesive.

[0068] S3, Curing and molding of the temperature-sensitive conductive encapsulation adhesive and preparation of the adhesive film: The temperature-sensitive conductive adhesive obtained in S2 was coated on an EVA substrate, and curing was performed under a 365 nm ultraviolet lamp at room temperature for 10 s, and molding was completed to obtain a temperature-sensitive conductive encapsulation adhesive film. The thickness of the temperature-sensitive conductive encapsulation adhesive film was 100 μm.

[0069] Comparative Example 1 A method for preparing a temperature-sensitive conductive encapsulation adhesive film, which is different from Example 1 in that no reinforcing resin is added, includes the following steps: S1, Preparation of an epoxy resin prepolymer: In a sample bottle, 10 g of EP was added, followed by 1.0 g of 1,4-butanediol diglycidyl ether as a diluent, and stirring was performed for 10 min to mix them uniformly. Then, 0.5 g of silane coupling agent KH-560 and 0.2 g of toughening agent phthalate were added, and stirring was continued for 10 min. Then, the sample bottle was placed in a vacuum degassing stirrer, and degassing was performed for 5 min under the condition of -0.1 MPa to obtain a uniform epoxy resin prepolymer solution.

[0070] S2, Preparation of the temperature-sensitive conductive encapsulation adhesive: The temperature-sensitive ceramic powder filler was added to the epoxy resin matrix solution obtained in S1, and the total mass of the ceramic filler was 70% of the mass of the resin solids. After initial mixing for 5 min, vacuum degassing was performed for 5 min. Then, 5.0 g of 4,4'-diamino diphenyl sulfone was added as a curing agent and 0.1 g of 2-ethyl-4-methyl imidazole was added as an accelerator. Then, the mixture was transferred to a three-roll mill, and grinding was performed four times to obtain a temperature-sensitive conductive encapsulation adhesive.

[0071] S3, Curing and molding of the temperature-sensitive conductive encapsulation adhesive and preparation of the adhesive film: The temperature-sensitive conductive adhesive obtained in S2 was coated on an EVA substrate, and curing was performed under a 365 nm ultraviolet lamp at room temperature for 10 s, and molding was completed to obtain a temperature-sensitive conductive encapsulation adhesive film. The thickness of the temperature-sensitive conductive encapsulation adhesive film was 100 μm.

[0072] Comparative Example 2 A method for preparing a temperature-sensitive conductive encapsulation adhesive film, which is different from Example 1 in that no temperature-sensitive ceramic powder is added, includes the following steps: S1, Preparation of epoxy resin prepolymer: 10 g of EP was added to a sample bottle, followed by 1.5 g of silicone-modified polyurethane, 1.0 g of 1,4-butanediol diglycidyl ether as a diluent, and stirring for 10 min to mix them evenly. Then 0.5 g of silane coupling agent KH-560 and 0.2 g of toughening agent phthalate were added, and after continuing to stir for 10 min, the sample bottle was placed in a vacuum degassing stirrer and degassed at -0.1 MPa for 5 min to obtain a uniform epoxy resin prepolymer solution.

[0073] S2, Preparation of conductive encapsulating adhesive: 5.0 g of 4,4'-diamino diphenyl sulfone was added as a curing agent and 0.1 g of 2-ethyl-4-methyl imidazole as an accelerator. Then the mixture was transferred to a three-roll mill and ground for 4 times to obtain a conductive encapsulating adhesive after sufficient dispersion.

[0074] S3, Curing and molding of conductive encapsulating adhesive and preparation of adhesive film: The conductive adhesive obtained in S2 was coated on the EVA substrate, and placed in an 80°C oven for 1 h of pre-curing, then the temperature was raised to 150°C for 2 h of curing, and finally post-cured at 180°C for 1 h, the molding was completed, and the conductive encapsulating adhesive film with a thickness of 100 μm was obtained.

[0075] Comparative Example 3 A method for preparing a temperature-sensitive conductive encapsulating adhesive film, which is different from Example 1 in that the temperature-sensitive ceramic powder is replaced by silver powder, comprising the following steps: S1, Preparation of epoxy resin prepolymer: 10 g of EP was added to a sample bottle, followed by 1.5 g of silicone-modified polyurethane, 1.0 g of 1,4-butanediol diglycidyl ether as a diluent, and stirring for 10 min to mix them evenly. Then 0.5 g of silane coupling agent KH-560 and 0.2 g of toughening agent phthalate were added, and after continuing to stir for 10 min, the sample bottle was placed in a vacuum degassing stirrer and degassed at -0.1 MPa for 5 min to obtain a uniform epoxy resin prepolymer solution.

[0076] S2, Preparation of temperature-sensitive conductive encapsulating adhesive: The silver powder filler was added to the epoxy resin matrix solution obtained in S1, and the total mass of the silver powder was 70% of the solid mass of the resin. After preliminary mixing for 5 min, vacuum degassing stirring was carried out for 5 min. Then 5.0 g of 4,4'-diamino diphenyl sulfone was added as a curing agent and 0.1 g of 2-ethyl-4-methyl imidazole as an accelerator. Then the mixture was transferred to a three-roll mill and ground for 4 times to obtain a temperature-sensitive conductive encapsulating adhesive after sufficient dispersion.

[0077] S3, curing molding of the temperature-sensitive conductive packaging adhesive and preparation of the adhesive film: the temperature-sensitive conductive packaging adhesive obtained in S2 was coated on an EVA substrate, pre-cured in an 80°C oven for 1 h, then gradually heated to 150°C for curing for 2 h, and finally post-cured at 180°C for 1 h, and the molding was completed to obtain a temperature-sensitive conductive packaging adhesive film. The thickness of the temperature-sensitive conductive packaging adhesive film was 100 μm.

[0078] Comparative Example 4 A method for preparing a temperature-sensitive conductive packaging adhesive film, which is different from Example 1 in that the diluent is replaced by an inert diluent, acetone, and comprises the following steps: S1, preparation of an epoxy resin prepolymer: 10 g of EP was added to a sample bottle, followed by 1.5 g of silicone-modified polyurethane, 1.0 g of acetone as a diluent, and stirring for 10 min to mix them uniformly. Then 0.5 g of silane coupling agent KH-560 and 0.2 g of toughening agent phthalate were added, and after continuing to stir for 10 min, the sample bottle was placed in a vacuum degassing stirrer and degassed at -0.1 MPa for 5 min to obtain a uniform epoxy resin prepolymer solution.

[0079] S2, preparation of a temperature-sensitive conductive packaging adhesive: the temperature-sensitive ceramic filler was added to the epoxy resin matrix solution obtained in S1, and the total mass of the ceramic filler was 70% of the mass of the resin solids. After preliminary mixing by stirring for 5 min, vacuum degassing stirring was performed for 5 min. Then 5.0 g of 4,4'-diamino diphenyl sulfone was added as a curing agent and 0.1 g of 2-ethyl-4-methyl imidazole was added as an accelerator. Then the mixture was transferred to a three-roll mill and ground for 4 times to obtain a temperature-sensitive conductive packaging adhesive.

[0080] S3, curing molding of the temperature-sensitive conductive packaging adhesive and preparation of the adhesive film: the temperature-sensitive conductive packaging adhesive obtained in S2 was coated on an EVA substrate, pre-cured in an 80°C oven for 1 h, then gradually heated to 150°C for curing for 2 h, and finally post-cured at 180°C for 1 h, and the molding was completed to obtain a temperature-sensitive conductive packaging adhesive film. The thickness of the temperature-sensitive conductive packaging adhesive film was 100 μm.

[0081] The conductive packaging adhesive films prepared in Examples 1-9 and Comparative Examples 1-4 were tested for performance, and the results are as follows.

[0082] Figure 3 The morphology structure diagrams of the temperature-sensitive conductive packaging adhesive films prepared in Example 1 and Example 5 are shown in Figure 3 (a) is Example 3, and (b) is Example 1. Figure 3As shown, when the content of temperature-sensitive ceramic is 30%, the scanning electron microscope morphology shows that the ceramic particles are uniformly distributed and isolated in the resin matrix, and the dispersion is good. However, the distribution distance between the particles is far, and the conductive path cannot be formed. When the content is 70%, the ceramic particles are in an aggregated state, and the particles can contact each other to form a continuous conductive network.

[0083] Table 1 Influence of epoxy resin type on the performance of encapsulation glue As shown in Table 1, the appearance of the temperature-sensitive encapsulation glue prepared by bisphenol A type epoxy resin and phenolic epoxy resin is relatively uniform, the continuity is good, and the adhesive strength changes little. Even at 200℃, it can still maintain an adhesive strength of more than 6Mpa. Both of them cannot obtain the volume resistivity at room temperature, indicating that the encapsulation glue is in an insulating state at room temperature. However, at 200℃, the encapsulation glue obtained by both of them is as low as 10 -4 Ω·cm, indicating that the encapsulation glue of both can form an effective electrical path at high temperature and has good high-temperature conductivity. The volume resistivity of the temperature-sensitive encapsulation glue prepared by bisphenol A type epoxy resin is 1.1×10 -4 Ω·cm, which is lower than 2.7×10 -4 Ω·cm of the temperature-sensitive encapsulation glue prepared by phenolic epoxy resin. It indicates that the temperature-sensitive encapsulation glue prepared by bisphenol A type epoxy resin has more excellent high-temperature conductivity. And they can all meet the application requirements of high-temperature packaging field under the temperature-sensitive mechanism.

[0084] Table 2 Influence of reinforced resin type on the performance of encapsulation glue As shown in Table 2, the appearance of the temperature-sensitive encapsulation glue prepared by organic silicon modified polyurethane and polyimide two kinds of reinforced resins is relatively uniform, the continuity is good, and the adhesive strength changes little. Even at 200℃, it can still maintain an adhesive strength of more than 7Mpa. However, the adhesive strength of the encapsulation glue without reinforced resin decreases significantly to 12.5Mpa, and the decrease is more significant at high temperature, which is 5.3Mpa, indicating that the reinforced resin has a significant influence on the high-temperature adhesion. The temperature-sensitive encapsulation glue prepared by organic silicon modified polyurethane and polyimide two kinds of reinforced resins and the encapsulation glue without reinforced resin cannot obtain the volume resistivity at room temperature, indicating that the encapsulation glue is in an insulating state at room temperature, and the reinforced resin has little influence on the conductivity at room temperature. However, at 200℃, the volume resistivity of the encapsulation glue system with or without reinforced resin is 10 -4 Ω·cm~10 -3Ω·cm, indicating that the encapsulation glue with or without the reinforcing resin can form effective electrical path at high temperature, and has good high temperature conductivity. The volume resistivity of the temperature-sensitive encapsulation glue prepared by the silicone-modified polyurethane is 1.1×10 -4 Ω·cm, which is lower than 3.2×10 -3 Ω·cm of the temperature-sensitive encapsulation glue prepared by the silicone-modified polyurethane, and is also lower than 1.7×10 -4 Ω·cm of the encapsulation glue system without the reinforcing resin. It is indicated that the reinforcing resin has little effect on the conductivity, but can significantly improve the bonding performance of the encapsulation glue at high temperature. The addition of the reinforcing resin can meet the application requirements of the high-temperature encapsulation field under the temperature-sensitive mechanism.

[0085] Table 3 Influence of curing agent type on encapsulation glue performance As shown in Table 3, the temperature-sensitive encapsulation glue prepared by the two curing agents has uniform appearance and good continuity, and the bonding strength changes little, that is, even at 200℃, the bonding strength can still be maintained above 7Mpa. However, the volume resistivity of the encapsulation glue cured by 4,4'-diamino diphenyl sulfone is as low as 1.1×10 -4 Ω·cm, and the volume resistivity of the encapsulation glue cured by methyl hexahydrophthalic amine is as high as 8.3×10 -2 Ω·cm. This may be because the polymer generated by the crosslinking reaction of the curing agent methyl hexahydrophthalic amine and the epoxy resin has strong interaction with the temperature-sensitive ceramic powder, so that the resin is firmly wrapped on the surface of the ceramic powder particles, which is not conducive to the formation of conductive path at high temperature, resulting in the volume resistivity being too large.

[0086] Table 4 Influence of temperature-sensitive ceramic powder type and content on encapsulation glue performance As shown in Table 4, the bonding strength of the encapsulation glue without temperature-sensitive ceramic is 19.5Mpa, but it is an insulator because it does not contain conductive components. With the addition of temperature-sensitive ceramic, the bonding strength gradually decreases from the initial 19.5Mpa to 17.5Mpa when the temperature-sensitive ceramic is 30%, to 15.8Mpa when the temperature-sensitive ceramic is 50%, to 14.8Mpa when the temperature-sensitive ceramic is 70%, and to 9.2Mpa when the temperature-sensitive ceramic is 80%, indicating that the bonding strength to the substrate gradually decreases with the addition of temperature-sensitive ceramic. The addition of 80% of the temperature-sensitive ceramic is too much, which can easily cause particle agglomeration and thus cause a significant decrease in the bonding performance. At the same time, the bonding strength at 200℃ also has the same decreasing rule, but it can still meet the bonding requirements of encapsulation.

[0087] However, with the addition of 50% to 80% of the temperature-sensitive ceramic, the volume resistivity of the encapsulation glue at high temperature gradually decreases from 3.6×10-2 Ω·cm to 6.4 x 10 -5 Ω·cm, the encapsulation adhesive gradually became conductive. When the amount of temperature-sensitive ceramic was 30%, the filler content was low, the filler particles were separated or isolated in the resin matrix, and the distance between the conductive particles was far, which could not form a conductive path. When the content of the filler exceeded the critical value, a large number of temperature-sensitive ceramic particles could contact each other to form a continuous conductive network.

[0088] As a control, the encapsulation adhesive prepared by using commercial silver powder as conductive filler had an adhesive strength of 11.5 MPa, but the adhesive performance decreased significantly at high temperature, as low as 4.2 MPa. Compared with the good conductivity at room temperature, such as 5.5 x 10 -4 Ω·cm, the conductivity decreased significantly at high temperature, such as 7.8 x 10 -2 Ω·cm, indicating that the conductivity was significantly affected by temperature. This is because silver will migrate in a humid and hot environment, greatly reducing its reliability. In addition, silver will be affected by the electric field in a humid environment, and will undergo electrolytic reaction due to the penetration of water molecules, forming a bypass resistance, and also accumulating to form branches, forming silver oxide at the junction, greatly reducing the high-temperature conductivity of the conductive adhesive and affecting the reliability of the equipment.

[0089] Table 5 Effect of diluent type on the performance of encapsulation adhesive As can be seen from Table 5, acetone is an inert diluent, and 1,4-butanediol diglycidyl ether is an active diluent. The epoxy active diluent can reduce the viscosity of the slurry, better blend the ceramic filler and the resin, and the epoxy functional group can further ring-opening curing to improve the adhesive performance, so the adhesive strength can reach 14.8 MPa, and still maintains 7.5 MPa at high temperature. Acetone does not participate in the curing reaction and cannot co-cure, so the adhesive strength is low, only 11.2 MPa, and at high temperature it decreases to 5.7 MPa. In addition, acetone as a diluent will quickly volatilize during the curing process, which can easily cause the aggregation of the filler, thereby reducing the conductivity, and the volume resistivity is 5.2 x 10 -3 Ω·cm, which is significantly higher than the 1.1 x 10 -4 Ω·cm of the encapsulation adhesive based on the diluent.

[0090] Table 6 Effect of resin type on the performance of encapsulation adhesive From table 6, it can be seen that the appearance of the temperature-sensitive packaging glue prepared from bisphenol A type epoxy resin and polyurethane resin is relatively uniform, the continuity is good, and the bonding strength changes little, even at 200 DEG C, it can still maintain the bonding strength of more than 6Mpa. The bonding strength of the packaging glue based on acrylate is slightly lower, but it can still meet the use requirements such as 200 DEG C, > 5MPa. The three kinds of packaging glue cannot obtain the volume resistivity at room temperature, indicating that the packaging glue is in an insulating state at room temperature. But at 200 DEG C, the obtained packaging glue is as low as 10 -4 Ω·cm, indicating that the three kinds of packaging glue can form effective electrical paths at high temperature and have good high-temperature conductivity. They can all meet the application requirements in the field of high-temperature packaging under the temperature-sensitive mechanism.

[0091] It should be noted that when the numerical range is involved in the present application, it should be understood that each numerical range of the two endpoints and any number between the two endpoints can be selected. Since the same steps and examples are used, the preferred embodiments are described in the present application to prevent redundancy. Although the preferred embodiments of the present application have been described, those skilled in the art can make additional changes and modifications to these embodiments once they know the basic creative concept. Therefore, the appended claims are intended to include the preferred embodiments and all changes and modifications falling within the scope of the present application.

[0092] Obviously, those skilled in the art can make various modifications and variations to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalent technologies, the present application also intends to include these modifications and variations.

Claims

1. A temperature-sensitive conductive encapsulating adhesive, characterized in that, The temperature-sensitive conductive encapsulant is formed by mixing and curing a resin prepolymer and a temperature-sensitive ceramic powder. The resin prepolymer is formed by mixing a base resin, a reinforcing resin, a diluent, a silane coupling agent, and a toughening agent. The mass ratio of the base resin, reinforcing resin, diluent, silane coupling agent, and toughening agent is 100:5~20:5~100:1~3:1~5. The mass ratio of the total amount of resin in the resin prepolymer to the temperature-sensitive ceramic powder is 100:30~85. The base resin is an epoxy resin, an acrylate resin, or a polyurethane resin. When the base resin is an epoxy resin, it is mixed and cured by adding a first curing agent and an accelerator. When the base resin is a polyurethane resin, it is mixed and cured by adding a second curing agent. When the base resin is an acrylate resin, it is cured by adding a photoinitiator. The reinforcing resin is at least one of silicone-modified polyurethane and silicone-modified polyimide, and the temperature-sensitive ceramic powder is a temperature-sensitive ceramic with a negative temperature coefficient of -2% / ℃ to -10% / ℃.

2. The temperature-sensitive conductive encapsulating adhesive according to claim 1, characterized in that, The temperature-sensitive ceramic with a negative temperature coefficient is at least one of MnO-CuO-O2, MnO-CoO-O2, MnO-NiO-O2, Mn-Co-Ni oxide, Mn-Cu-N, Mn-Cu-Co oxide, Sb and P-doped SnO2 ceramic powder.

3. The temperature-sensitive conductive encapsulating adhesive according to claim 1, characterized in that, The epoxy resin is at least one of bisphenol A type epoxy resin, phenolic epoxy resin, and naphthalene ring type epoxy resin; the acrylate resin is at least one of polyurethane acrylate, epoxy acrylate, and organosilicon modified acrylate resin; and the main agent of the polyurethane resin is at least one of polypropylene glycol, polypropylene triol, and polytetrahydrofuran.

4. The temperature-sensitive conductive encapsulating adhesive according to claim 1, characterized in that, When the matrix resin is an epoxy resin, the amount of diluent used is 5% to 20% of the matrix resin mass, and the diluent is at least one of methyl acetal glycerol ether, butyl glycidyl ether, 1,4-butanediol diglycidyl ether, or neopentyl glycol diglycidyl ether; when the matrix resin is an acrylate resin, the amount of diluent used is 5% to 40% of the matrix resin mass, and the diluent is at least one of 1,6-hexanediol diacrylate, isobornyl acrylate, hydroxyethyl methacrylate, and tetrahydrofuran acrylate; when the matrix resin is a polyurethane resin, the amount of diluent used is 5% to 100% of the matrix resin mass, and the diluent is at least one of acetone and ethyl acetate.

5. The temperature-sensitive conductive encapsulating adhesive according to claim 1, characterized in that, When the matrix resin is an epoxy resin, the mass ratio of the first curing agent to the matrix resin is 0.2 to 1.2:1, the amount of accelerator is 1% to 5% of the mass of the matrix resin, the first curing agent is at least one of aliphatic curing agent, acid anhydride curing agent, and imidazole curing agent, and the accelerator is at least one of phenol, dodecylamine, and n-butanol. When the matrix resin is a polyurethane resin, the mass ratio of the second curing agent to the matrix resin is 0.2 to 0.5:1, and the second curing agent is at least one of toluene diisocyanate, diphenylmethane diisocyanate, naphthalene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate and 1,4-cyclohexane diisocyanate-based curing agents. When the matrix resin is an acrylate resin, the amount of photoinitiator is 1% to 5% of the mass of the matrix resin, and the photoinitiator is at least one of 2-hydroxy-2-methyl-1-phenylpropanone, 1-hydroxycyclohexylphenyl ketone, and benzoin ether.

6. The temperature-sensitive conductive encapsulating adhesive according to claim 1, characterized in that, The silane coupling agent is at least one of KH-550 or KH-560, and the toughening agent is at least one of phthalate and fumed silica.

7. A method for preparing the temperature-sensitive conductive encapsulating adhesive according to any one of claims 1 to 6, characterized in that, Includes the following steps: The matrix resin, reinforcing resin, diluent, silane coupling agent and toughening agent are mixed and stirred to form a resin prepolymer; Thermosensitive ceramic powder is added to the resin prepolymer and dispersed evenly. Then, a first curing agent and accelerator, or a second curing agent, or a photoinitiator are added. After being dispersed evenly, degassing and grinding are performed to obtain thermosensitive conductive encapsulant.

8. A temperature-sensitive conductive encapsulating film, characterized in that, The temperature-sensitive conductive encapsulating adhesive according to any one of claims 1 to 6 is cast onto an adhesive film carrier and cured to obtain a temperature-sensitive conductive encapsulating adhesive film, wherein the thickness of the temperature-sensitive conductive encapsulating adhesive film is 10 μm to 500 μm.

9. The temperature-sensitive conductive encapsulating film according to claim 8, characterized in that, The film carrier is EVA vinyl acetate and ethylene copolymer, POE butene and octene copolymer, polyethylene or polypropylene.

10. The temperature-sensitive conductive encapsulating film according to claim 8, characterized in that, When the base resin is an epoxy resin, it is first pre-cured at 50℃~100℃ for 1h~2h, then cured at 120℃~150℃ for 2h~3h, and finally cured at 180℃ for 1h~3h; when the base resin is a polyurethane resin, it is first pre-cured at 50℃~80℃ for 1h~2h, then cured at 100℃~150℃ for 1h~3h; when the base resin is an acrylate resin, it is cured with ultraviolet light at a wavelength of 365nm for 1s~30s.

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