Low-modulus high-strength adhesive as well as preparation method and application thereof

Abstract

The invention belongs to a power battery adhesive technology, and particularly relates to a low-modulus high-strength adhesive as well as a preparation method and application thereof. The adhesive comprises a component A and a component B, the component A comprises low-modulus silane modified polyether resin, modified hydroxyalkyl silicone oil, a light stabilizer, a heat stabilizer, a moisture scavenger, nano calcium carbonate, a flame retardant, a coupling agent, epoxy and a curing agent; the component B comprises epoxy resin, a low-modulus monomer, nano calcium carbonate, a flame retardant and a catalyst. The low-modulus and high-strength adhesive provided by the invention has excellent bonding strength on base materials such as aluminum, stainless steel, PA, PC, FR4 and PET, has the properties of low modulus, high strength, flame retardance, excellent wide temperature range, damp-heat aging resistance and the like, and can effectively ensure that the performance of a power battery is stable when the power battery is used for a long time in complex environments such as high-frequency vibration, damp-heat, severe cold, intense summer heat and heat accumulation; and the reliability and the safety are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to a low modulus high strength adhesive, its preparation method and application, and belongs to the technical field of power battery adhesives. BACKGROUND

[0002] The power battery module provides power source for new energy vehicles. In actual use, the power battery module is sealed by the shell frame to ensure safety. At present, the sealing is mainly ensured by the joint action of adhesives and welding. The adhesives mainly adopt polyurethane structural adhesives, but the existing polyurethane structural adhesives have the disadvantages of low high-temperature strength and poor low-temperature toughness, which are difficult to meet the requirements of the present power battery.

[0003] In the application of traditional power battery adhesives, the bonding strength is a core performance index. Its importance is reflected in two aspects: on the one hand, the adhesive needs to have a strong interfacial bonding effect on the substrate, so as to form a stable connection at the interface; on the other hand, the adhesive itself also needs to have a high cohesive effect to ensure the stability of the overall bonding structure. However, high-strength materials usually exhibit hard and strong characteristics, while low-modulus materials often exhibit soft and tough or soft and weak characteristics. In the field of adhesives, adhesives with high cohesive effect generally have high modulus, but power batteries often face complex and variable dynamic environments such as vibration during application. High-modulus adhesives cannot effectively absorb stress through damping, which can easily cause the adhesive to crack and make the entire bonding system fail, thus failing to meet the long-term stable operation requirements of power batteries. Based on the above reasons, it is extremely challenging to achieve low modulus characteristics while ensuring strong bonding performance, and there is a fundamental contradiction between strength and softness. Therefore, how to design a soft and strong adhesive material has become a key difficulty and technical bottleneck faced by the current power battery structural adhesive.

[0004] In summary, the existing power battery adhesives have obvious deficiencies in application. It is of great application value to develop an adhesive that has a strong interfacial bonding effect on the substrate while balancing the strength and softness of the adhesive system performance, and to provide a hybrid structural adhesive for power battery assembly with a low modulus of less than 200 MPa and a high strength of more than 9 MPa. SUMMARY

[0005] The present application provides a low modulus high strength adhesive, a preparation method and application thereof, and solves the problems in the prior art.

[0006] The technical scheme for solving the above technical problems is as follows: a low modulus high strength adhesive, the adhesive comprises A component and B component; in terms of weight fraction, the A component comprises: low modulus silane modified polyether resin 30-70 parts, modified hydrocarbyl silicone oil 5-25 parts, light stabilizer 0.05-0.3 parts, thermal stabilizer 0.05-0.3 parts, water removal agent 0.5-3 parts, nano calcium carbonate 10-30 parts, flame retardant 10-30 parts, coupling agent 1-5 parts, and epoxy curing agent 2-10 parts; the B component comprises: epoxy resin 30-70 parts, low modulus monomer 1-10 parts, nano calcium carbonate 10-30 parts, flame retardant 10-30 parts, and catalyst 0.05-1 part.

[0007] Further, the weight ratio of the A component to the B component is (1-1.2):1.

[0008] Further, the low modulus silane modified polyether resin is polyether resin capped at both ends of a molecular chain by dimethoxysilane, and the viscosity at 25 DEG C is 500-50000 mPa s.

[0009] Preferably, the dimethoxysilane-capped polyether resin is at least one of alpha-dimethoxysilane-capped polyether resin with a number average molecular weight of 8500-15000 g / mol and dimethoxysilane-capped polyether resin with a viscosity of 7000-46000 mPa s at 25 DEG C.

[0010] Further, the modified hydrocarbyl silicone oil is prepared according to the following steps: (1) hydrocarbyl silicone oil is dehydrated under reduced pressure at 100-115 DEG C for 2-4 h; (2) after cooling, isocyanate silane coupling agent is added under inert gas conditions, and the reaction is carried out at 80-90 DEG C, and the isocyanate silane coupling agent modified hydrocarbyl silicone oil is obtained after the reaction, wherein the functional group molar ratio NCO:OH= (1.01-1.4):1 is used for proportioning.

[0011] Further, the hydrocarbyl silicone oil is preferably linear polydimethylsiloxane containing primary hydrocarbyl functional groups at both ends of the molecule.

[0012] Further, the isocyanate-based silane coupling agent is at least one of diphenylmethane diisocyanate, dicyclohexylmethane diisocyanate, toluene diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, liquid diphenylmethane diisocyanate (MDI), polymeric diphenylmethane diisocyanate (MDI), hexamethylene diisocyanate (HDI) trimer, and toluene diisocyanate (TDI) trimer.

[0013] Further, the light stabilizer is at least one of a hindered amine light stabilizer and a liquid light stabilizer mixture, wherein the liquid light stabilizer mixture includes a benzotriazole-based ultraviolet light absorber and a hindered amine light stabilizer.

[0014] Further, the hindered amine light stabilizer is preferably at least one of Tinuvin 292 and Tinuvin 770, and the liquid light stabilizer mixture is preferably Tinuvin 5050.

[0015] Further, the heat stabilizer is at least one of β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid octadecyl ester and pentaerythritol tetrakis(bis-T-butylhydroxyhydrocinnamate) ester.

[0016] Further, the water removal agent is at least one of vinyltrimethoxysilane, vinyltriethoxysilane, hexamethyldisilazane, and p-toluenesulfonylisocyanate.

[0017] Further, the nano calcium carbonate is at least one of KLNM-S034, KLNM-S035, CCS-18, and CCS-25.

[0018] Further, the flame retardant is a solid flame retardant or a liquid flame retardant.

[0019] Further, the solid flame retardant is at least one of aluminum hydroxide, magnesium hydroxide, aluminum hypophosphite, and aluminum diethylphosphinate.

[0020] Further, the liquid flame retardant is at least one of liquid flame retardants such as tricresyl phosphate, triethyl phosphate, and tris(chloroisopropyl)phosphate.

[0021] Further, the coupling agent is at least one of γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-(β-aminoethyl)-γ-aminopropylmethyldimethoxysilane, N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, and γ-(methacryloyloxy)propyltrimethoxysilane.

[0022] Further, the epoxy curing agent is at least one of 2,4,6-tris(dimethylaminomethyl)phenol, t-butyl phenol, triethylene tetramine.

[0023] Further, the epoxy resin is at least one of bisphenol A epoxy resin, bisphenol F epoxy resin.

[0024] Further, the low modulus monomer is at least one of polyethylene glycol, polytetrahydrofuran diol, polypropylene glycol, polycaprolactone diol, polylactic acid diol, polycarbonate diol.

[0025] Further, the catalyst is at least one of dibutyl tin dilaurate, dibutyl tin diacetylacetone, stannous octoate, zinc isooctoate, bismuth isooctoate.

[0026] The application also discloses a preparation method of the low modulus high strength adhesive. S1, preparation of component A: S1-1, dehydration step: under inert gas, low modulus silane modified polyether resin, modified hydrocarbon-based silicone oil, light stabilizer, thermal stabilizer, nano calcium carbonate and flame retardant are mixed and subjected to dehydration treatment; S1-2, mixing step: after cooling, water removing agent, coupling agent and epoxy curing agent are sequentially added under inert gas, and component A is obtained after uniform mixing; S2, preparation of component B: Under inert gas, epoxy resin, low modulus monomer, nano calcium carbonate and flame retardant are uniformly mixed, and a catalyst is added, and component B is prepared after stirring.

[0027] S3, preparation of the adhesive: After component A and component B are uniformly mixed according to a certain weight ratio, the low modulus high strength adhesive is obtained.

[0028] Further, in the dehydration step S1-1 in S1, the temperature condition is 115-130 DEG C, and the dehydration time is 2-3h.

[0029] In the mixing step S1-2 in S1, cooling is performed at 20-50 DEG C; In the mixing step S1-2 in S1, the vacuum degree is controlled to be 0.095-0.5 MPa in the mixing step, and the treatment time is 0.5-1h.

[0030] In step S2, the preparation of component B is controlled at a temperature of 20-50 DEG C, a vacuum degree of 0.095-0.5 MPa and a treatment time of 0.5-1h.

[0031] In step S3, component A and component B are mixed according to a weight ratio of (1-1.2):1.

[0032] The application further discloses an application of the low-modulus high-strength adhesive.

[0033] The application has the following advantages: (1) The low-modulus high-strength adhesive is prepared by adding a proper amount of isocyanate silane coupling agent to modify hydroxyl alkyl silicone oil in the A component, effectively reducing the modulus of the structural adhesive, and the silane coupling agent can condense with the hydroxyl group on the surface of the base material to form a covalent bond, still maintaining a high enough tensile strength and shear strength; the isocyanate silane coupling agent modified hydroxyl alkyl silicone oil after curing and the low-modulus silane modified polyether resin in the A component form a strong chemical bond, and the epoxy resin in the B component can form an interpenetrating crosslinking network structure, which can block water vapor from entering and improve the heat aging resistance; the addition of the low-modulus monomer can improve the hydrophobicity of the molecular chain, improve the moisture heat aging resistance, and at the same time, can increase the flexibility of the molecular chain, and the modulus is lower to a certain extent; the addition of the epoxy resin improves the rigidity of the molecular chain, improves the glass transition temperature, and improves the heat resistance; by controlling the reasonable amount of each component, the components interact with each other, and finally the low-modulus high-strength adhesive with excellent performance is obtained, effectively improving the bonding strength of PET, PC and metal base materials.

[0034] (2) The low-modulus high-strength adhesive has a low modulus, and the storage modulus is less than 200 MPa at 25 DEG C, which makes it have excellent buffering and damping effect when applied to power batteries. In addition, the adhesive has high strength, the tensile strength of the body is greater than 9 MPa, the shear strength of the base materials such as PET, PC, aluminum alloy and steel is greater than 9 MPa, which ensures the safety and reliability during driving. At the same time, it has excellent moisture heat aging resistance, and the shear strength attenuation is less than 20% after 1000h of double 85 aging.

[0035] (3) The low-modulus high-strength adhesive has excellent bonding strength on aluminum, stainless steel, PA, PC, FR4, PET and other base materials, and has low modulus, high strength, flame retardation, excellent wide temperature range, moisture heat aging resistance and other properties, effectively ensuring the performance stability of the power battery under complex environments such as high-frequency vibration, moisture heat, severe cold, scorching heat and heat accumulation, improving the reliability and safety. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1 The figure is a test figure of the storage modulus of the low-modulus high-strength adhesive obtained in Example 2. DETAILED DESCRIPTION

[0037] The specific embodiments of the present application will be described in detail below. The present application can be implemented in many different ways than described herein, and those skilled in the art can make similar improvements without departing from the spirit of the present application, so the present application is not limited to the specific embodiments disclosed.

[0038] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used only for the purpose of describing specific embodiments, not for limiting the present application.

[0039] The components used in the examples and comparative examples of the present application are only for better explanation of the present application technology, and are not a limitation of the present application technology, and the sources of the components not mentioned are all commercially available.

[0040] A low modulus high strength adhesive, the adhesive comprises A component and B component; in the A component, each component comprises: low modulus silane modified polyether resin 30-70 parts, modified hydrocarbon-based silicone oil 5-25 parts, light stabilizer 0.05-0.3 parts, thermal stabilizer 0.05-0.3 parts, water removal agent 0.5-3 parts, nano calcium carbonate 10-30 parts, flame retardant 10-30 parts, coupling agent 1-5 parts, epoxy curing agent 2-10 parts; in the B component, each component comprises: epoxy resin 30-70 parts, low modulus monomer 1-10 parts, nano calcium carbonate 10-30 parts, flame retardant 10-30 parts, catalyst 0.05-1 parts.

[0041] Specifically, the weight ratio of the A component to the B component is (1-1.2):1.

[0042] Specifically, the low modulus silane modified polyether resin is a polyether resin with both ends of the molecular chain capped by dimethoxysilane, and the viscosity at 25°C is 500-50000 mPa·s.

[0043] Preferably, the dimethoxysilane-capped polyether resin is at least one of an α-dimethoxysilane-capped polyether resin with a number average molecular weight of 8500-15000 g / mol and a dimethoxysilane-capped polyether resin with a viscosity at 25°C of 7000-46000 mPa·s.

[0044] More specifically, the low modulus silane modified polyether resin in the example of the present application is selected from GENIOSIL@STP-E10 and GENIOSIL@STP-E30 produced by Wacker Chemie (China) Co., Ltd. Among them, the number average molecular weight of GENIOSIL@STP-E10 is about 8889 g / mol; the number average molecular weight of GENIOSIL@STP-E30 is about 14493 g / mol.

[0045] The dimethoxysilane-terminated polyether resin with viscosity of 7000-46000 Pa·s at 25℃ in the embodiment of the application is selected from KANEKA MS resin S203H, KANEKA MS resin SAX260 and KANEKA MS resin SAX750 produced by KANEKA Corporation of Japan. Among them, the KANEKA MS resin S203H has viscosity of 8000 mPa·s at 25℃ and modulus M100=0.14 MPa; the KANEKA MS resin SAX260 has viscosity of 7000 mPa·s at 25℃ and modulus M30=0.24 MPa; and the SAX750 has viscosity of 46000 mPa·s at 25℃ and modulus M50=0.32 MPa.

[0046] Specifically, the modified hydrocarbyl silicone oil is prepared according to the following steps: (1) The hydrocarbyl silicone oil is added into a single-neck flask with a suction head, stirring is started, the vacuum valve is slowly opened for vacuumizing, and the vacuumizing and stirring are maintained under the condition of slow heating to 100-115℃, and the dehydration is maintained for 2-4 h; (2) The temperature is lowered to below 50℃, nitrogen is slowly filled, and the isocyanate-based silane coupling agent is added under the condition of nitrogen atmosphere; the temperature is raised to 80-90℃, and the reaction is maintained for 2-4 h, to obtain the isocyanate-based silane coupling agent modified hydrocarbyl silicone oil, wherein the functional group molar ratio NCO:OH=(1.01-1.4):1 is used for proportioning.

[0047] Whether the reaction is complete is determined according to the reaction of the isocyanate group with excess di-n-butylamine to produce urea, and the NCO content is quantitatively titrated by using hydrochloric acid to titrate the excess di-n-butylamine. When the color changes from blue to yellow, it is considered that the reaction is complete, and the reaction is ended.

[0048] In the embodiment of the application, nitrogen is used to provide inert conditions, but this does not constitute a limitation of the application. Argon can also be used according to the actual operation needs.

[0049] More specifically, the hydrocarbyl silicone oil used in the preparation process of the modified hydrocarbyl silicone oil is preferably linear polydimethylsiloxane containing primary hydrocarbyl functional groups at both ends of the molecule.

[0050] The hydrocarbyl silicone oil in the embodiment of the application is TZ 1301 purchased from Nanjing Zizhe Chemical Co., Ltd.

[0051] More specifically, the isocyanate-based silane coupling agent is at least one of diphenylmethane diisocyanate, dicyclohexylmethane diisocyanate, toluene diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, liquefied diphenylmethane diisocyanate (MDI), polymeric diphenylmethane diisocyanate (MDI), hexamethylene diisocyanate (HDI) trimer, and toluene diisocyanate (TDI) trimer.

[0052] Specifically, the light stabilizer is at least one of a hindered amine light stabilizer and a liquid light stabilizer mixture, wherein the liquid light stabilizer mixture comprises a benzotriazole-based ultraviolet light absorber and a hindered amine light stabilizer.

[0053] The hindered amine light stabilizer is preferably at least one of Tinuvin 292 and Tinuvin 770, and the liquid light stabilizer mixture is preferably Tinuvin 5050.

[0054] The light stabilizer involved in the embodiments of the present application is at least one of Tinuvin 292, Tinuvin 770, and Tinuvin 5050 produced by BASF in Germany.

[0055] Tinuvin 292 is a mixture of (1,2,2,6,6-pentamethyl-4-piperidyl) sebacic acid and 1-(methyl)-8-(1,2,2,6,6-pentamethyl-4-piperidyl) sebacic acid; Tinuvin 770 is (bis 2,2,6,6-tetramethyl-4-piperidyl) sebacate; and Tinuvin 5050 is a mixture of 2-(2-hydroxyphenyl)-benzotriazole UVA and basic HALS.

[0056] Specifically, the heat stabilizer is at least one of β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionic acid octadecyl ester and pentaerythritol tetra(bis-T-butylhydroxyhydrocinnamate) ester.

[0057] Specifically, the water removal agent is at least one of vinyltrimethoxysilane, vinyltriethoxysilane, hexamethyldisilazane, and p-toluenesulfonylisocyanate.

[0058] Specifically, the nano calcium carbonate in the embodiments of the present application is at least one of KLNM-S034, KLNM-S035, CCS-18, and CCS-25.

[0059] KLNM-S034 and KLNM-S035 are produced by Jingmen Dongbao District Kelong Mining Company; and CCS-18 and CCS-25 are produced by Guangxi Huana New Material Co., Ltd.

[0060] Specifically, the flame retardant is a solid flame retardant or a liquid flame retardant.

[0061] More specifically, the solid flame retardant is at least one of aluminum hydroxide, magnesium hydroxide, aluminum hypophosphite, and aluminum diethyl phosphinate.

[0062] In the embodiment of the present application, the aluminum hydroxide has a D50=10 μm, and the magnesium hydroxide has a D50=8 μm. The average particle size of the solid flame retardant does not constitute a limitation of the present application, and mainly achieves good dispersion effect when mixed with other components, and plays a flame-retardant role.

[0063] More specifically, the liquid flame retardant is at least one of tricresyl phosphate, triethyl phosphate, and tris(chloroisopropyl) phosphate.

[0064] Specifically, the coupling agent is at least one of γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-(β-aminoethyl)-γ-aminopropylmethyldimethoxysilane, N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane, γ-glyceryl ether oxypropyltrimethoxysilane, and γ-(methacryloyloxy)propyltrimethoxysilane.

[0065] Specifically, the epoxy curing agent is at least one of 2,4,6-tris(dimethylaminomethyl)phenol, t-butylphenol, and triethylenetetramine.

[0066] Specifically, the epoxy resin is at least one of bisphenol A epoxy resin and bisphenol F epoxy resin.

[0067] More specifically, the epoxy resin is at least one of NPEL-128, NPEL-128E, NPES-609, and NPEF-170 produced by Taiwan Nanya Epoxy Resin (Kunshan) Co., Ltd.

[0068] Specifically, the low-modulus monomer is at least one of polyethylene glycol, polytetrahydrofuran diol, polypropylene glycol, polycaprolactone diol, polylactic acid diol, and polycarbonate diol.

[0069] Specifically, the catalyst is at least one of dibutyltin dilaurate, dibutyltin diacetylacetonate, stannous octoate, zinc isooctoate, and bismuth isooctoate.

[0070] The present application also discloses a preparation method of the low-modulus high-strength adhesive. S1, preparation of component A: S1-1, dehydration step: low-modulus silane-modified polyether resin, modified hydrocarbon-based silicone oil, light stabilizer, heat stabilizer, nano calcium carbonate, and flame retardant are added into a planetary stirred tank, and stirred at 115-130°C for 2-3h under nitrogen atmosphere for dehydration treatment. S1-2, mixing step: cooling to 20~50℃, under nitrogen atmosphere, adding water removing agent, coupling agent, epoxy curing agent in turn, controlling vacuum degree to be 0.095~0.5MPa, stirring for 0.5~1h;After mixing uniformly, A component is obtained; S2, preparation of B component: Epoxy resin, low modulus monomer, nano calcium carbonate and flame retardant are added into planetary stirring kettle, under nitrogen atmosphere, stirring until mixing uniformly under the condition of controlling temperature to be 20~50℃;Under nitrogen protection state, adding catalyst, controlling vacuum degree to be 0.095~0.5MPa, stirring for 0.5~1h to prepare B component.

[0071] S3, preparation of adhesive: After mixing A component and B component according to certain weight ratio, low modulus high strength adhesive is obtained.

[0072] The application further discloses application of the low modulus high strength adhesive.

[0073] The quantity of each component involved in the examples and comparative examples of the application is calculated according to weight fraction, the component types and the component quantity involved in the examples of the application are shown in table 1, and the component types and the component quantity involved in the comparative examples of the application are shown in table 2.

[0074] Example 1 The modified hydroxyalkyl silicone oil is prepared according to the following steps: (1) hydroxyalkyl silicone oil is added into a single-neck flask with a suction head, stirring is started, vacuum is slowly opened, and the vacuum and stirring state is kept under the condition of slowly heating to 100~115℃, and dehydrating for 3h; (2) cooling to below 50℃, nitrogen is slowly filled, and under the condition of nitrogen atmosphere, isocyanate silane coupling agent diphenyl methane diisocyanate is added;The reaction is carried out under the condition of heating to 80~90℃ for 2~4h, the NCO content is determined according to the reaction of isocyanate group and excessive di-n-butylamine to produce urea, and the excessive di-n-butylamine is titrated with hydrochloric acid, the color changes from blue to yellow, and the reaction is considered to be completely reacted, the reaction is ended, and isocyanate silane coupling agent modified hydroxyalkyl silicone oil is obtained, wherein, the functional group molar ratio NCO:OH=1.3:1 is used for matching.

[0075] A low modulus high strength adhesive is prepared, specifically including the following steps: S1, preparation of A component: S1-1, dehydration step: 45 parts of low modulus silane modified polyether resin GENIOSIL@STP-E10, 10 parts of modified hydroxyalkyl silicone oil prepared in Example 1, 0.2 parts of light stabilizer Tinuvin5050, 0.2 parts of heat stabilizer pentaerythritol tetrakis (bis-T-butyl hydroxyl hydrogenated cinnamic acid) ester, 15 parts of nano calcium carbonate CCS-18, 19 parts of flame retardant aluminum hydroxide (D50=10 μm) are added to a planetary stirred tank, and stirred at 100-130℃ for 2-3h under nitrogen atmosphere for dehydration treatment; S1-2, mixing step: cooled to 20-50℃, and then added 2 parts of water removing agent vinyl trimethoxysilane, 4 parts of coupling agent γ-aminopropyl trimethoxysilane, 5 parts of epoxy curing agent 2, 4, 6-tris (dimethylaminomethyl) phenol under nitrogen atmosphere, and controlled the vacuum degree to be 0.095-0.5MPa, and stirred for 0.5h; after mixing uniformly, A component was obtained; S2, preparation of B component: The epoxy resin 45 parts of NPEL-128, 5 parts of low modulus monomer polyethylene glycol, 20 parts of nano calcium carbonate CCS-18, 18 parts of flame retardant aluminum hydroxide (D50=10 μm), and 12 parts of triethyl phosphate are added to a planetary stirred tank, and stirred to be mixed uniformly under nitrogen atmosphere with the temperature controlled to be 20-50℃; under nitrogen protection, a catalyst is added, and the vacuum degree is controlled to be 0.095-0.5MPa, and stirred for 0.5-1h to prepare B component.

[0076] S3, preparation of adhesive: After the A component and the B component are mixed uniformly according to the weight ratio of 1:1, a low modulus high strength adhesive is obtained.

[0077] Example 2 Preparation of modified hydroxyalkyl silicone oil, the same method as Example 1 is adopted in Example 2, and the difference lies in that the isocyanate-based silane coupling agent is hexamethylene isocyanate in the process of preparing the modified hydroxyalkyl silicone oil.

[0078] Preparation of a low modulus high strength adhesive, the same method as Example 1 is adopted in Example 2, and the difference lies in that the modified hydroxyalkyl silicone oil is prepared by the preparation method provided in the present embodiment, and the types and amounts of other components are different, and the specific components and amounts are shown in Table 1. The test graph of the storage modulus of the low modulus high strength adhesive obtained in Example 2 is shown in Figure 1 .

[0079] Example 3 Preparation of modified hydroxyalkyl silicone oil, the same method as Example 1 is adopted in Example 3, and the difference lies in that the isocyanate-based silane coupling agent is isophorone diisocyanate in the process of preparing the modified hydroxyalkyl silicone oil.

[0080] Preparation of a low modulus high strength adhesive, the same method as in Example 1 is used in this embodiment 3, the difference is that the modified hydrocarbyl silicone oil is prepared by the preparation method provided in this embodiment, and the types and amounts of other components are different, the specific components and amounts are shown in Table 1.

[0081] Example 4 Preparation of modified hydrocarbyl silicone oil, the same method as in Example 1 is used in this embodiment 4, the difference is that in the process of preparing the modified hydrocarbyl silicone oil, the isocyanate silane coupling agent is polymeric diphenylmethane diisocyanate (MDI).

[0082] Preparation of a low modulus high strength adhesive, the same method as in Example 1 is used in this embodiment 4, the difference is that the modified hydrocarbyl silicone oil is prepared by the preparation method provided in this embodiment, and the types and amounts of other components are different, the specific components and amounts are shown in Table 1.

[0083] Example 5 Preparation of modified hydrocarbyl silicone oil, the same method as in Example 1 is used in this embodiment 5, the difference is that: In step (1), the dehydration treatment is 2h; In step (2), the functional group molar ratio NCO:OH is 1.01:1.

[0084] Preparation of a low modulus high strength adhesive, the same method as in Example 1 is used in this embodiment 6, the difference is that the modified hydrocarbyl silicone oil is prepared by the preparation method provided in this embodiment, and the types and amounts of other components are different, the specific components and amounts are shown in Table 1.

[0085] Example 6 Preparation of modified hydrocarbyl silicone oil, the same method as in Example 1 is used in this embodiment 6, the difference is that: In step (1), the dehydration treatment is 4h; In step (2), the functional group molar ratio NCO:OH is 1.4:1.

[0086] Preparation of a low modulus high strength adhesive, the same method as in Example 1 is used in this embodiment 4, the difference is that the modified hydrocarbyl silicone oil is prepared by the preparation method provided in this embodiment, and the types and amounts of other components are different, the specific components and amounts are shown in Table 1.

[0087] Example 7 Preparation of modified hydrocarbyl silicone oil, the same method as in Example 1 is used in this embodiment 7. Preparation of a low modulus high strength adhesive, this embodiment 7 uses the same method as embodiment 1, the difference is that the types and amounts of each component are different, the A component and the B component are mixed uniformly according to the weight ratio of 1.2:1 to obtain a low modulus high strength adhesive. The specific components and amounts are shown in table 1.

[0088] Comparative example 1 Preparation of a low modulus high strength adhesive, this comparative example 1 uses the same method as embodiment 1, the difference is that no modified hydrocarbon group silicone oil is added, and the types and amounts of other components are also different, the specific components and amounts are shown in table 2.

[0089] Comparative example 2 Preparation of a low modulus high strength adhesive, this comparative example 2 uses the same method as embodiment 1, the difference is that no modified hydrocarbon group silicone oil is added, but hydrocarbon group silicone oil TZ 1301 is added, and the types and amounts of other components are also different, the specific components and amounts are shown in table 2.

[0090] Comparative example 3 Preparation of a low modulus high strength adhesive, this comparative example 3 uses the same method as embodiment 1, the difference is that no modified hydrocarbon group silicone oil is added, but hydrocarbon group silicone oil TZ 1301 is added, and no low modulus monomer is added, and the types and amounts of other components are also different, the specific components and amounts are shown in table 2.

[0091] Comparative example 4 Preparation of modified hydrocarbon group silicone oil, this comparative example 4 uses the same method as embodiment 1, the difference is that: In step (1), dehydration treatment is carried out at 80℃ for 3h.

[0092] Preparation of a low modulus high strength adhesive, this comparative example 4 uses the same method as embodiment 1, the difference is that the modified hydrocarbon group silicone oil is prepared by the preparation method provided in this embodiment, and the types and amounts of other components are the same as those in embodiment 1, the specific components and amounts are shown in table 2.

[0093] Comparative example 5 Preparation of modified hydrocarbon group silicone oil, this comparative example 5 uses the same method as embodiment 1, the difference is that: In step (2), the reaction temperature is 60℃.

[0094] Preparation of a low modulus high strength adhesive, this comparative example 5 uses the same method as embodiment 1, the difference is that the modified hydrocarbon group silicone oil is prepared by the preparation method provided in this embodiment, and the types and amounts of other components are the same as those in embodiment 1, the specific components and amounts are shown in table 2.

[0095] Comparative example 6 Preparation of modified hydroxyalkyl silicone oil, the present comparative example 6 uses the same method as example 1, the difference is that: In step (2), the reaction temperature is 110℃.

[0096] Preparation of a low modulus high strength adhesive, the present comparative example 6 uses the same method as example 1, the difference is that: the modified hydroxyalkyl silicone oil is prepared by the preparation method provided in the present example, and the types and amounts of other components are the same as those in example 1. The specific components and amounts are shown in table 2.

[0097] Comparative example 7 Preparation of modified hydroxyalkyl silicone oil, the present comparative example 7 uses the same method as example 1, the difference is that: In step (2), the functional group molar ratio NCO:OH is 0.8:1.

[0098] Preparation of a low modulus high strength adhesive, the present comparative example 7 uses the same method as example 1, the difference is that: the modified hydroxyalkyl silicone oil is prepared by the preparation method provided in the present example, and the types and amounts of other components are the same as those in example 1. The specific components and amounts are shown in table 2.

[0099] Comparative example 8 Preparation of modified hydroxyalkyl silicone oil, the present comparative example 8 uses the same method as example 1, the difference is that: In step (2), the functional group molar ratio NCO:OH is 2:1.

[0100] Preparation of a low modulus high strength adhesive, the present comparative example 8 uses the same method as example 1, the difference is that: the modified hydroxyalkyl silicone oil is prepared by the preparation method provided in the present example, and the types and amounts of other components are the same as those in example 1. The specific components and amounts are shown in table 2.

[0101] Comparative example 9 Preparation of modified hydroxyalkyl silicone oil, the present comparative example 9 uses the same method as example 1.

[0102] Preparation of a low modulus high strength adhesive, the present comparative example 9 uses the same method as example 1, the difference is that: the A component and the B component are mixed uniformly according to the weight ratio of 0.8:1 to obtain a low modulus high strength adhesive.

[0103] Comparative example 10 Preparation of modified hydroxyalkyl silicone oil, the present comparative example 10 uses the same method as example 1.

[0104] A low modulus high strength adhesive is prepared. In the present comparative example 10, the same method as in example 1 is used, except that the A component and the B component are mixed in a weight ratio of 2:1 to obtain a low modulus high strength adhesive.

[0105] Table 1: Component types and amounts involved in the examples of the present application

[0106] Table 2: Component types and amounts involved in the comparative examples of the present application

[0107] The low modulus high strength adhesives prepared in the examples and comparative examples of the present application are tested for performance. The specific test items and standards involved are as follows: Tensile strength at 25℃: The tensile strength is tested under standard conditions (25℃, 50% RH), and the sample preparation and testing are carried out in accordance with the requirements of GB / T 528-2009.

[0108] Shear strength: The sample preparation and testing are carried out in accordance with the requirements of GB / T 7124-2008.

[0109] In order to test the excellent bonding strength of the low modulus high strength adhesive provided by the present application to aluminum (AL), stainless steel, PA, PC, FR4, PET and other substrates, the present application takes AL and PET materials as examples, applies the low modulus high strength adhesive prepared by the present application to the surface of AL or PET material, and tests the shear strength performance of the sample.

[0110] Storage modulus: The DMA modulus is tested in accordance with the requirements of ASTM E1640-23. The specific sample size is between 1 mm thick x 5 mm wide x 20 mm long and 1 mm thick x 10 mm wide x 50 mm long. The temperature range is -40℃ to 100℃, the heating rate is 1℃ / min, the tensile clamp is used, the test frequency is 0.1 Hz, and the clamping length is 0.1%.

[0111] Shear strength after double 85 aging: The test object is placed in a constant temperature and humidity chamber with a temperature setting of 85℃±3℃ and a humidity setting of RH 82%-88% for 1000 h, then taken out, and tested for performance after 24 h at room temperature.

[0112] Flame retardant performance: Tested in accordance with the requirements of GB / T 2408-2021.

[0113] The performance test data involved in the low modulus high strength adhesives prepared in the examples and comparative examples are shown in Table 3.

[0114] Table 3 Performance test data related to low modulus high strength adhesives prepared in Examples

[0115] Table 4 Performance test data related to low modulus high strength adhesives prepared in Comparative Examples 1-3

[0116] Table 5 Performance test data related to low modulus high strength adhesives prepared in Examples 1 and Comparative Examples 4-9

[0117] As can be seen from the test data in Table 3, the low modulus high strength adhesives obtained according to the preparation method provided in the present application in Examples 1-7 have a low modulus (less than 200 MPa); have excellent tensile strength, and excellent shear strength (> 9 MPa) for untreated AL and PET surfaces; have an excellent wide temperature range, and still have good shear strength at high temperature 60°C and low temperature -30°C, and the flame retardant performance can reach UL94-V0 level, and the shear strength attenuation is less than 20% after 1000h of double 85 aging, which can effectively ensure the performance stability of the power battery under complex environments such as high-frequency vibration, heat and humidity, severe cold, scorching heat, heat accumulation, etc. during long-term use, and improve reliability and safety.

[0118] According to the data in Tables 1-4, it can be seen from the comparison of the experimental data of Comparative Example 1 and the examples of the present application that the strength of the adhesive obtained in Comparative Example 1 is obviously not as good as that of the adhesive prepared according to the method provided in the present application, and the storage modulus is obviously high. This is because the preparation method provided in the present application adds modified hydrocarbyl silicone oil, which forms a strong chemical bond with the low modulus silane-modified polyether resin in component A, can play a permanent plasticizing role, avoid migration, bleeding and volatilization of small molecule silicone oil, and enhance the strength of the chemical crosslinking point of the material. Form a firm "interpenetrating network" with the epoxy resin in component B, enhance the coating and interfacial action of inorganic fillers, further improve the adhesion to various substrates, strengthen the chemical bonding between the adhesive and the adherend, and make the adhesive have high aging performance and strength. In Comparative Example 1, no modified hydrocarbyl silicone oil is added, so these advantages are lost, which affects the performance of the adhesive.

[0119] According to the data in Table 1-Table 4, from the comparison of the experimental data of Comparative Example 2 and the inventive examples, it can be seen that the strength of the adhesive obtained in Comparative Example 2 is obviously not as good as the adhesive prepared according to the method provided in the present application, and the storage modulus is obviously high. This is because, in Comparative Example 2, hydroxyalkyl silicone oil is used instead of the modified hydroxyalkyl silicone oil provided in the present application. The modified hydroxyalkyl silicone oil provided in the present application is modified hydroxyalkyl silicone oil modified by isocyanate silane coupling agent, which introduces high-activity functional group -NCO, which can form strong chemical bonds with low-modulus silane-modified polyether resin, form a firm "interpenetrating network" with epoxy resin, and together with other components to make the adhesive have excellent performance. However, the hydroxyalkyl silicone oil used in Comparative Example 2 does not provide such high-activity functional groups.

[0120] According to the data in Table 1-Table 4, from the comparison of the experimental data of Comparative Example 3 and the inventive examples, it can be seen that the strength of the adhesive obtained in Comparative Example 3 is obviously not as good as the adhesive prepared according to the method provided in the present application, and the storage modulus is obviously high. This is because, in Comparative Example 3, hydroxyalkyl silicone oil is used instead of the modified hydroxyalkyl silicone oil provided in the present application, and low-modulus monomers are lacking in component B, which affects the interaction between the components, making the performance of the finally prepared adhesive not as good as the adhesive provided in the present application.

[0121] According to the data in Table 1, Table 2, Table 3 and Table 5, from the comparison of the experimental data of Comparative Example 4 and Inventive Example 1, it can be seen that the strength of the adhesive obtained in Comparative Example 4 is obviously not as good as the adhesive prepared according to the method provided in the present application, and the storage modulus is obviously high. This is because the modification of hydroxyalkyl silicone oil is mainly achieved by the reaction of highly active isocyanate groups with hydroxyl groups to form urethane bonds, so that the modified hydroxyalkyl silicone oil contains a certain proportion of hydroxyl groups and modified hydroxyalkyl silicone oil. In the preparation process of the modified hydroxyalkyl silicone oil in Comparative Example 4, dehydration is carried out at 80°C in step (1), which is lower than the temperature set in the present application, resulting in incomplete dehydration. In step (2), a part of the isocyanate silane coupling agent is deactivated, which makes the functional group hydroxyl in the modified hydroxyalkyl silicone oil significantly higher than the urethane bond, affecting the final performance of the material when added to the adhesive.

[0122] According to the data in Table 1, Table 2, Table 3 and Table 5, from the comparison of the experimental data of Comparative Example 5 and Inventive Example 1, it can be seen that the strength of the adhesive obtained in Comparative Example 5 is obviously not as good as the adhesive prepared according to the method provided in the present application, and the storage modulus is obviously high. This is because, in the preparation process of the modified hydroxyalkyl silicone oil in Comparative Example 5, the reaction is carried out at 60°C in step (2), which is lower than the temperature set in the present application, resulting in incomplete reaction. The modified hydroxyalkyl silicone oil obtained is added to the adhesive, affecting the final performance of the material.

[0123] According to the data in Table 1, Table 2, Table 3 and Table 5, it can be seen from the comparison of the experimental data of Comparative Example 6 and Example 1 of the present application that the strength of the adhesive obtained in Comparative Example 6 is obviously not as good as that of the adhesive prepared according to the method provided in the present application. This is because, in the preparation of the modified hydrocarbyl silicone oil in Comparative Example 6, the reaction is carried out at 110°C in step (2), which is higher than the temperature set in the present application, and the modified hydrocarbyl silicone oil obtained affects the final performance of the material when added to the adhesive.

[0124] According to the data in Table 1, Table 2, Table 3 and Table 5, it can be seen from the comparison of the experimental data of Comparative Example 7 and Example 1 of the present application that the strength of the adhesive obtained in Comparative Example 7 is obviously not as good as that of the adhesive prepared according to the method provided in the present application, and the storage modulus is obviously higher. This is because, in the preparation of the modified hydrocarbyl silicone oil in Comparative Example 7, the functional group molar ratio NCO:OH = 0.8:1 is used for proportioning in step (2), which makes the amount of cyanate-based silane coupling agent added too small, and the content of hydroxyl groups in the modified hydrocarbyl silicone oil obtained is obviously higher than that of the urethane bond content, which finally affects the final performance of the material when added to the adhesive.

[0125] According to the data in Table 1, Table 2, Table 3 and Table 5, it can be seen from the comparison of the experimental data of Comparative Example 8 and Example 1 of the present application that the strength of the adhesive obtained in Comparative Example 8 is obviously not as good as that of the adhesive prepared according to the method provided in the present application, and the storage modulus is obviously higher. This is because, in the preparation of the modified hydrocarbyl silicone oil in Comparative Example 8, the functional group molar ratio NCO:OH = 2:1 is used for proportioning in step (2), which makes the amount of cyanate-based silane coupling agent added too large, and the content of hydroxyl groups in the modified hydrocarbyl silicone oil obtained is obviously lower than that of the urethane bond content, which finally affects the final performance of the material when added to the adhesive.

[0126] According to the data in Table 1, Table 2, Table 3 and Table 5, it can be seen from the comparison of the experimental data of Comparative Example 9 and Example 1 of the present application that the strength of the adhesive obtained in Comparative Example 9 is obviously not as good as that of the adhesive prepared according to the method provided in the present application, and the storage modulus is obviously higher. This is because, in the preparation of the low modulus high strength adhesive in Comparative Example 9, the A component and the B component are mixed in a weight ratio of 0.8:1, which makes the A component too small, the MS component in the component is reduced, and the B component epoxy component is relatively too large, which finally affects the final performance of the material when added to the adhesive.

[0127] According to the data in Table 1, Table 2, Table 3 and Table 5, it can be seen from the comparison of the experimental data of Comparative Example 10 and Example 1 of the present application that the strength of the adhesive obtained in Comparative Example 10 is obviously lower than that of the adhesive prepared according to the method provided in the present application, and the storage modulus is obviously higher. This is because, in the preparation of the low modulus high strength adhesive, the A component and the B component are mixed in a weight ratio of 2:1 in Comparative Example 10, which makes the A component too much, the MS component in the component too much, and the B component epoxy component relatively too little, finally added to the adhesive, which affects the final performance of the material.

[0128] The technical features of the above-described embodiments can be combined in any manner. For the sake of brevity, not all possible combinations of the technical features in the above-described embodiments are enumerated, however, as long as the combinations of the technical features do not contradict each other, they should be considered as within the scope of the present disclosure.

[0129] Those skilled in the art will appreciate that, without departing from the concept of the present application, several modifications and improvements can be made, which are within the scope of the present application, and the scope of protection of the present application is subject to the appended claims.

Claims

1. A low modulus high strength adhesive characterized by, The adhesive comprises a component A and a component B; In the component A, each component comprises, by weight fraction: Low modulus silane modified polyether resin 30-70 parts, modified hydroxyl alkyl silicone oil 5-25 parts, light stabilizer 0.05-0.3 parts, thermal stabilizer 0.05-0.3 parts, water removal agent 0.5-3 parts, nano calcium carbonate 10-30 parts, flame retardant 10-30 parts, coupling agent 1-5 parts, epoxy curing agent 2-10 parts; In the component B, each component comprises: Epoxy resin 30-70 parts, low modulus monomer 1-10 parts, nano calcium carbonate 10-30 parts, flame retardant 10-30 parts, catalyst 0.05-1 parts.

2. The low modulus, high strength adhesive of claim 1 wherein, The weight ratio of the component A to the component B is (1-1.2):

1.

3. The low modulus, high strength adhesive of claim 1 wherein, The low modulus silane modified polyether resin is a polyether resin with both ends of the molecular chain capped by dimethoxysilane, and the viscosity at 25℃ is 500-50000 mPa·s.

4. The low modulus, high strength adhesive of claim 1 wherein, The modified hydroxyl alkyl silicone oil is prepared according to the following steps: (1) The hydroxyl alkyl silicone oil is dehydrated under reduced pressure at 100-115℃ for 2-4h; (2) After cooling, the isocyanate silane coupling agent is added under inert gas condition, and the reaction is carried out at 80-90℃. The isocyanate silane coupling agent modified hydroxyl alkyl silicone oil is obtained after the reaction is completed, wherein the functional group molar ratio NCO:OH=(1.01-1.4):1 is used for proportioning.

5. The low modulus, high strength adhesive of claim 4 wherein, The isocyanate silane coupling agent is at least one of diphenylmethane diisocyanate, dicyclohexylmethane diisocyanate, toluene diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, liquefied diphenylmethane diisocyanate, polymeric diphenylmethane diisocyanate, hexamethylene diisocyanate trimer and toluene diisocyanate trimer.

6. The low modulus high strength adhesive according to claim 1, wherein, The thermal stabilizer is at least one of β-(3,5-di-tert-butyl-4-hydroxyphenyl) octadecyl propionate and pentaerythritol tetra(bis-T-butyl hydroxyhydrocinnamate); The water removal agent is at least one of vinyltrimethoxysilane, vinyltriethoxysilane, hexamethyldisilazane and p-toluenesulfonylisocyanate; The flame retardant is a solid flame retardant or a liquid flame retardant; The solid flame retardant is at least one of aluminum hydroxide, magnesium hydroxide, aluminum hypophosphite and aluminum diethyl phosphinate; The liquid flame retardant is at least one of liquid flame retardants such as tricresyl phosphate, triethyl phosphate and tris(chloroisopropyl) phosphate; The coupling agent is at least one of γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-(β-aminoethyl)-γ-aminopropylmethyldimethoxysilane, N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane, γ-glyceryl ether oxypropyltrimethoxysilane and γ-(methacryloyloxy)propyltrimethoxysilane; The epoxy curing agent is at least one of 2,4,6-tris(dimethylaminomethyl) phenol, tert-butyl phenol and triethylenetetramine.

7. The low modulus, high strength adhesive of claim 1 wherein, The epoxy resin is at least one of bisphenol A epoxy resin and bisphenol F epoxy resin. The low modulus monomer is at least one of polyethylene glycol, polytetrahydrofuran diol, polypropylene glycol, polycaprolactone diol, polylactic acid diol, and polycarbonate diol. The catalyst is at least one of dibutyltin dilaurate, dibutyltin diacetylacetone, stannous octoate, zinc isooctoate, and bismuth isooctoate.

8. A process for the preparation of a low modulus high strength adhesive as claimed in any one of claims 1 to 7, wherein, The preparation method comprises the following steps: S1, preparation of component A: S1-1, dehydration step: under inert gas, mix low modulus silane modified polyether resin, modified hydrocarbon-based silicone oil, light stabilizer, heat stabilizer, nano calcium carbonate, and flame retardant, and perform dehydration treatment; S1-2, mixing step: after cooling, under inert gas, sequentially add water removal agent, coupling agent, and epoxy curing agent, and mix uniformly to obtain component A; S2, preparation of component B: Under inert gas, mix epoxy resin, low modulus monomer, nano calcium carbonate, and flame retardant, and mix uniformly, add catalyst, and stir to prepare component B; S3, preparation of adhesive: Mix component A and component B uniformly to obtain low modulus high strength adhesive.

9. The process for preparing a low modulus high strength adhesive as claimed in claim 8, wherein, In the dehydration step S1-1, the temperature condition is 115-130℃, and the dehydration time is 2-3h; In the mixing step S1-2, the temperature is cooled to 20-50℃ for treatment; In the mixing step S1-2, the vacuum degree in the mixing step is controlled to be 0.095-0.5MPa, and the treatment time is 0.5-1h; In step S2, the preparation of component B is controlled at a temperature of 20-50℃, a vacuum degree of 0.095-0.5MPa, and a treatment time of 0.5-1h; In step S3, component A and component B are mixed at a weight ratio of (1-1.2):

1.

10. Use of a low modulus high strength adhesive according to any one of claims 1 to 7, characterized in that, The adhesive is applied to a power battery module.

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