High-strength and high-temperature-resistant polyurethane structural potting adhesive for power battery filling and preparation method thereof

Abstract

The invention discloses a high-strength and high-temperature resistant polyurethane structural potting adhesive for power battery caulking and a preparation method thereof, belonging to the field of potting adhesives, comprising: A and B components, A and B components are used in a mass ratio of 1:1, and the molar ratio of functional groups of A and B components is: NCO:OH=1.05:1-1.5:1; A component consists of: 15-50 parts of bio-based polyol, 15-50 parts of aromatic ring modified polyol, 10-40 parts of polyether polyol, 0.001-0.1 parts of catalyst, 5-30 parts of enhancer, and diluent. 0.001-10 parts, 0.001-5 parts of coupling agent, 0.001-5 parts of dehydrating agent and 0.001-5 parts of thixotropic agent; component B consists of 0.001-50 parts of isocyanate, 0.001-60 parts of terminal isocyanate polyurethane prepolymer, 30-75 parts of terminal isocyanate bio-based polyol prepolymer, 0.001-30 parts of isocyanate silane coupling agent, 0.001-0.1 parts of catalyst, 0.001-10 parts of diluent and 0.001-0.3 parts of water absorbent. The potting glue can ensure the stable performance of power batteries, high adhesion, safety and reliability, and meet the packaging requirements.

Description

Technical Field

[0001] The invention relates to the technical field of polyurethane potting adhesives, and in particular to a high-strength and high-temperature-resistant polyurethane structural potting adhesive for power battery caulking. Background Art

[0002] Power batteries are the core components of new energy vehicles, and their packaging design is directly related to the safety, life and performance stability of the battery. During the operation of power batteries, packaging materials need to withstand complex working conditions, such as:

[0003] (1) Mechanical strength requirements: The packaging material needs to have sufficient strength and toughness to resist vibration and mechanical shock, while preventing material cracking caused by thermal expansion and contraction;

[0004] (2) High temperature resistance: When the power battery is charged and discharged at high rates or operates in harsh environments, its temperature may rise to 80°C or even higher. Therefore, the filling material needs to have excellent high temperature resistance and thermal aging stability;

[0005] (3) Insulation and sealing: The sealing material must effectively prevent the leakage of electrolyte and the intrusion of external moisture and dust, while providing good electrical insulation performance to avoid the risk of short circuit.

[0006] Although there are currently gap filling materials such as epoxy resin, silicone rubber and polyurethane on the market, there is still room for improvement in comprehensive performance, and it is difficult to fully meet the high requirements of power battery packaging, mainly including the following points:

[0007] (1) Epoxy resin: Epoxy resin is widely used in the field of electronic packaging due to its high strength, chemical resistance and excellent bonding properties. However, it shows a significant tendency to embrittlement in high temperature environments: first, its toughness is insufficient. Epoxy resin has high rigidity and lacks sufficient flexibility to resist stress concentration caused by thermal cycles; second, epoxy resin has complex processability and usually requires a long curing time. In addition, the curing process releases heat, which is not conducive to thick layer potting.

[0008] (2) Silicone rubber material: Silicone rubber material is known for its excellent elasticity, high temperature resistance and chemical inertness, but it has disadvantages in the field of structural potting: first, its mechanical strength is insufficient. The tensile strength and shear strength of silicone rubber are low, and it is difficult to withstand long-term vibration and mechanical stress; second, silicone rubber material has poor adhesion and limited adhesion ability on different substrates, and cannot provide reliable structural support.

[0009] (3) Polyurethane materials: Polyurethane materials have attracted attention for their good mechanical properties and diverse formulations, but existing polyurethane potting adhesives still have deficiencies in other aspects: first, the heat resistance of polyurethane materials is limited. Traditional polyurethanes will soften and age in high temperature environments, affecting the mechanical properties and service life of the materials; second, the processing performance of polyurethane materials still has room for improvement. Some polyurethane systems have a slow curing speed or require high-temperature curing, which is not conducive to large-scale industrial applications.

[0010] In recent years, through the modification research of polyurethane system, the development of new polyurethane potting adhesives has become an important direction to solve the problem of power battery packaging. The demand for high-performance potting materials in the field of power battery packaging is also increasing rapidly.

[0011] Therefore, how to develop a polyurethane structural potting adhesive that has high strength, excellent high temperature resistance and good electrical insulation has become a technical problem in the current power battery packaging field.

[0012] In view of this, the present invention is proposed. Summary of the invention

[0013] The purpose of the present invention is to provide a high-strength and high-temperature resistant polyurethane structural potting glue for power battery filling and a preparation method thereof, which not only has excellent mechanical strength and bonding properties for general substrates such as aluminum, steel, PET, and plastic, but also has excellent high temperature resistance, chemical corrosion resistance, electrical insulation performance and wet heat aging performance, and can maintain stable performance under complex operating conditions, thereby solving the above-mentioned technical problems existing in the prior art.

[0014] The objective of the present invention is achieved through the following technical solutions:

[0015] A high-strength and high-temperature resistant polyurethane structural potting adhesive for power battery caulking, comprising:

[0016] Component A and component B, wherein component A and component B are used in a mass ratio of 1:1, and the functional group molar ratio of component A to component B is: NCO:OH=1.05:1-1.5:1;

[0017] The component A is composed of the following raw materials in parts by mass: 15-50 parts of bio-based polyol, 15-50 parts of aromatic ring modified polyol, 10-40 parts of polyether polyol, 0.001-0.1 parts of catalyst, 5-30 parts of reinforcing agent, 0.001-10 parts of diluent, 0.001-5 parts of coupling agent, 0.001-5 parts of dehydrating agent and 0.001-5 parts of thixotropic agent;

[0018] The component B is composed of the following raw materials in parts by mass: 0.001 to 50 parts of isocyanate, 0.001 to 60 parts of isocyanate-terminated polyurethane prepolymer, 30 to 75 parts of isocyanate-terminated bio-based polyol prepolymer, 0.001 to 30 parts of isocyanate-based silane coupling agent, 0.001 to 0.1 parts of catalyst, 0.001 to 10 parts of diluent and 0.001 to 0.3 parts of water absorbent.

[0019] Preferably, in the component A of the above potting glue, the bio-based polyol is one or more of soybean oil, castor oil, palm oil, aromatic ring-modified castor oil, and aromatic ring-modified soybean oil;

[0020] The aromatic ring modified polyol is one or more of bisphenol A modified polyether diol, polyester diol, bisphenol F modified polyether diol, 4,4'-diaminodiphenylmethane modified polyether or polyester diol, benzyl alcohol modified polyether or polyester diol, phenolic polyol, melamine modified aromatic ring polyol, phthalic anhydride polyester diol with a molecular weight of 400 to 3000;

[0021] The polyether polyol is one or more of glycerol polyether or polyester triol, trimethylolpropane polyether or polyester polyol, pentaerythritol polyether or polyester polyol, ethylenediamine modified polyether, sorbitol polyether, and sugar polyether with a molecular weight of less than 1000.

[0022] Preferably, in the component A of the above potting glue, the reinforcing agent is one or more of aluminum hydroxide, magnesium hydroxide, aluminum hypophosphite, silicon powder, calcium carbonate, and montmorillonite;

[0023] The coupling agent is one or more of 3-(methacryloyloxy)propyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-glycidyloxypropyltrimethoxysilane, γ-methacryloyloxypropyltrimethoxysilane, and diamino-functional silane;

[0024] The dewatering agent is aluminosilicate;

[0025] The thixotropic agent is one or more of fumed silica and organic bentonite.

[0026] Preferably, the catalysts in the components A and B of the above-mentioned potting glue are one or more of dibutyltin dilaurate, stannous octoate, bismuth isooctanoate, bismuth laurate, bismuth neodecanoate, zinc isooctanoate, and zinc neodecanoate;

[0027] The diluents in the A component and the B component are one or more of dibutyl phthalate, di(2-ethylhexyl) phthalate, diisononyl phthalate, tri(2-chloropropyl) phosphate, and triethyl phosphate.

[0028] Preferably, in the component B of the above-mentioned potting glue, the isocyanate is one or more of toluene diisocyanate, diphenylmethane diisocyanate, isophorone diisocyanate, p-phenylene diisocyanate, 1,5-diisocyanatonaphthalene, modified liquefied MDI, polymerized MDI, MDI dimer, TDI dimer, MDI trimer, and TDI trimer;

[0029] The isocyanate-terminated polyurethane prepolymer is produced by reacting a diol with a molecular weight of 1000 to 3000 with an isocyanate, and the mass fraction of the NCO content is 10 to 25%;

[0030] The isocyanate-terminated bio-based polyol prepolymer is produced by the reaction of bio-based polyol and isocyanate, and the mass fraction of the NCO content is 10-25%.

[0031] Preferably, in the above-mentioned potting glue, the diol in the terminal isocyanate polyurethane prepolymer is one or more of polypropylene glycol, polyethylene glycol, polyethylene adipate glycol diol, polyneopentyl adipate glycol diol, and polyhexamethylene dimer glycol diol;

[0032] The isocyanate in the isocyanate-terminated polyurethane prepolymer is one or more of toluene diisocyanate, diphenylmethane diisocyanate, isophorone diisocyanate, p-phenylene diisocyanate, 1,5-diisocyanatonaphthalene, modified liquefied MDI, polymeric MDI, MDI dimer, TDI dimer, MDI trimer and TDI trimer.

[0033] Preferably, in the above-mentioned potting glue, the bio-based polyol in the isocyanate-terminated bio-based polyol prepolymer is one or more of soybean oil, castor oil, palm oil, aromatic ring-modified castor oil, and aromatic ring-modified soybean oil;

[0034] The isocyanate in the terminal isocyanate bio-based polyol prepolymer is one or more of toluene diisocyanate, diphenylmethane diisocyanate, isophorone diisocyanate, p-phenylene diisocyanate, 1,5-diisocyanatonaphthalene, modified liquefied MDI, polymeric MDI, MDI dimer, TDI dimer, MDI trimer, and TDI trimer.

[0035] Preferably, in the component B of the above-mentioned potting glue, the isocyanate silane coupling agent is one or more of isocyanate propyl trimethoxy silane, isocyanate propyl triethoxy silane, isocyanate methyl trimethoxy silane, isocyanate methyl triethoxy silane, isocyanate propyl dimethoxy silane, isocyanate cyclopentyl trimethoxy silane, and isocyanate phenyl trimethoxy silane;

[0036] The water absorbing agent is p-toluenesulfonyl isocyanate.

[0037] A method for preparing the high-strength and high-temperature resistant polyurethane structural potting adhesive for power battery caulking according to the present invention comprises the following steps:

[0038] According to the formula of component A and component B of the present invention, the raw materials of component A and component B are taken respectively.

[0039] The raw materials of component A and the raw materials of component B are mixed evenly to obtain component A and component B, and the obtained component A and component B are mixed evenly in a mass ratio of 1:1 and then used to obtain a high-strength and high-temperature resistant polyurethane structural potting adhesive for power battery filling.

[0040] Preferably, in the above method, the isocyanate-terminated polyurethane prepolymer in component B is prepared in the following manner, including:

[0041] The diol is heated to 110-120° C., stirred and vacuumed, dehydrated for 1-3 hours, cooled to below 50° C., filled with nitrogen, and isocyanate is added in a ratio of 10-25% of the theoretical NCO mass percentage, heated to 65-90° C., stirred and reacted for 1-3 hours, until the titrated NCO content no longer changes, the reaction is terminated, and cooled to room temperature to obtain an isocyanate-terminated polyurethane prepolymer;

[0042] The isocyanate-terminated bio-based polyol prepolymer in the B component is prepared in the following manner, including:

[0043] The bio-based polyol is heated to 110-120° C., stirred and vacuumed, dehydrated for 1-3 hours, cooled to below 50° C., filled with nitrogen, and isocyanate is added at a ratio of 10-25% of the theoretical NCO mass percentage. The temperature is raised to 65-90° C., and the reaction is stirred for 1-3 hours until the titrated NCO content no longer changes, and the reaction is terminated. The bio-based polyol prepolymer with terminal isocyanate group is obtained.

[0044] Compared with the prior art, the high-strength and high-temperature resistant polyurethane structural potting adhesive for power battery caulking and the preparation method thereof provided by the present invention have the following beneficial effects:

[0045] By adding an appropriate amount of bio-based polyols to component A, which are natural and biodegradable, the dependence on petrochemical resources is significantly reduced, and it can meet increasingly stringent environmental regulations, improving environmental protection and performance; bio-based polyols have a molecular rigid structure, and the aromatic ring skeleton gives polyurethane a higher modulus and strength, and has hydrophobic properties, greatly improving tensile strength, shear strength and aging properties. At the same time, the flexible aliphatic chain segment can significantly improve the flexibility and impact resistance of polyurethane, thereby increasing the system modulus and high temperature performance.

[0046] By adding an appropriate amount of aromatic ring modified polyol to component A, the polyol has multiple active groups, which react with isocyanate to form a polyurethane network with high cross-linking density, improve the modulus and high temperature resistance, and enhance the adhesion between the polyurethane and the substrate. The aromatic ring gives the material higher rigidity and high temperature stability, while enhancing the mechanical strength of the potting compound, and the phenolic group and high nitrogen content group can improve the flame retardant performance.

[0047] By adding a proper amount of polyether polyol into component A, the polyether polyol has multiple hydroxyl groups, so that a dense cross-linked network is formed after the polyurethane is cured, the modulus and high temperature resistance are improved, and the adhesion between the polyurethane and the substrate is increased.

[0048] By adding an appropriate amount of terminal isocyanate bio-based polyols to component B, the bio-based polyols have a molecular rigid structure, and the aromatic ring skeleton gives the polyurethane a higher modulus and strength. In addition, the bio-based polyols have high functionality, which can increase the cross-linking density, form a denser network structure, and greatly improve the tensile strength and shear strength; at the same time, the flexible aliphatic chain segment can significantly improve the flexibility and impact resistance of the polyurethane, thereby increasing the system modulus and high temperature performance.

[0049] By adding an appropriate amount of isocyanate silane coupling agent to component B, an interpenetrating cross-linked network structure can be formed, which can block the entry of water vapor, improve the resistance to moisture and heat aging, and also effectively improve the bonding strength to PET, PC and metal substrates.

[0050] Compared with the prior art, the present invention has at least the following beneficial effects:

[0051] (1) High modulus, storage modulus ≥30MPa at 60°C, excellent high temperature resistance when used in power battery PACK adhesive;

[0052] (2) High strength: the bulk tensile strength at 25°C is ≥30MPa, the bulk tensile strength at 60°C is ≥8MPa, the bonding shear strength at 25°C for substrates such as PET, PC, aluminum alloy, and steel is ≥10MPa, and the bonding shear strength at 60°C is ≥5MPa, ensuring the adhesion, safety, and reliability of the power battery;

[0053] (3) Excellent resistance to moisture and heat aging. After 1000h of double 85 aging, the tensile strength and shear strength decayed by less than 20%. DETAILED DESCRIPTION

[0054] The following is a clear and complete description of the technical solutions in the embodiments of the present invention in combination with the specific content of the present invention; it is obvious that the described embodiments are only part of the embodiments of the present invention, not all of the embodiments, which does not constitute a limitation of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the protection scope of the present invention.

[0055] First, the terms that may be used in this article are explained as follows:

[0056] The term “and / or” means that either or both of them can be realized at the same time. For example, X and / or Y means both “X” or “Y” and “X and Y”.

[0057] The terms "include", "comprises", "contains", "has" or other descriptions with similar semantics should be interpreted as non-exclusive inclusion. For example, including certain technical feature elements (such as raw materials, components, ingredients, carriers, dosage forms, materials, dimensions, parts, components, mechanisms, devices, steps, procedures, methods, reaction conditions, processing conditions, parameters, algorithms, signals, data, products or products, etc.) should be interpreted as including not only certain technical feature elements explicitly listed, but also other technical feature elements known in the art that are not explicitly listed.

[0058] The term "consisting of..." means excluding any technical feature elements not explicitly listed. If this term is used in a claim, it will make the claim closed, so that it does not contain technical feature elements other than those explicitly listed, except for conventional impurities related to them. If this term only appears in a clause of a claim, it only limits the elements explicitly listed in that clause, and the elements recorded in other clauses are not excluded from the overall claim.

[0059] The term "parts by mass" refers to the mass ratio relationship between multiple components. For example, if it is described that component X is x parts by mass and component Y is y parts by mass, then the mass ratio of component X to component Y is x:y. 1 part by mass can represent any mass, for example, 1 part by mass can be represented as 1 kg or 3.1415926 kg. The sum of the parts by mass of all components is not necessarily 100 parts, but can be greater than 100 parts, less than 100 parts or equal to 100 parts. Unless otherwise specified, the parts, proportions and percentages described herein are all measured by mass.

[0060] When concentration, temperature, pressure, size or other parameters are expressed in the form of a numerical range, the numerical range should be understood to specifically disclose all ranges formed by the pairing of any upper limit, lower limit, and preferred value in the numerical range, regardless of whether the range is explicitly stated; for example, if a numerical range of "2 to 8" is stated, the numerical range should be interpreted as including ranges such as "2 to 7", "2 to 6", "5 to 7", "3 to 4 and 6 to 7", "3 to 5 and 7", "2 and 5 to 7", etc. Unless otherwise specified, the numerical ranges stated herein include both their end values ​​and all integers and fractions within the numerical range.

[0061] The scheme provided by the present invention is described in detail below. The contents not described in detail in the embodiments of the present invention belong to the prior art known to professionals in the field. If the specific conditions are not specified in the embodiments of the present invention, they are carried out according to the conventional conditions in the field or the conditions recommended by the manufacturer. If the manufacturers are not specified in the reagents or instruments used in the embodiments of the present invention, they are all conventional products that can be purchased commercially.

[0062] The embodiment of the present invention provides a high-strength and high-temperature resistant polyurethane structural potting adhesive for power electrical caulking, comprising:

[0063] Component A and component B, wherein component A and component B are used in a mass ratio of 1:1, and the functional group molar ratio of component A to component B is NCO:OH=1.05:1-1.5:1;

[0064] The component A is composed of the following raw materials in parts by mass: 15-50 parts of bio-based polyol, 15-50 parts of aromatic ring modified polyol, 10-40 parts of polyether polyol, 0.001-0.1 parts of catalyst, 5-30 parts of reinforcing agent, 0.001-10 parts of diluent, 0.001-5 parts of coupling agent, 0.001-5 parts of dehydrating agent and 0.001-5 parts of thixotropic agent;

[0065] The component B is composed of the following raw materials in parts by mass: 0.001 to 50 parts of isocyanate, 0.001 to 60 parts of isocyanate-terminated polyurethane prepolymer, 30 to 75 parts of isocyanate-terminated bio-based polyol prepolymer, 0.001 to 30 parts of isocyanate-based silane coupling agent, 0.001 to 0.1 parts of catalyst, 0.001 to 10 parts of diluent, and 0.001 to 0.3 parts of water absorbent.

[0066] Preferably, in the component A of the above potting glue, the bio-based polyol is one or more of soybean oil, castor oil, palm oil, aromatic ring-modified castor oil, and aromatic ring-modified soybean oil;

[0067] Preferably, in the component A of the above-mentioned potting glue, the aromatic ring modified polyol adopts one or more of bisphenol A modified polyether or polyester diol with a molecular weight of 400 to 3000, bisphenol F modified polyether diol, 4,4'-diaminodiphenylmethane modified polyether or polyester diol, benzyl alcohol modified polyether or polyester diol, phenolic polyol, melamine modified aromatic ring polyol, phthalic anhydride polyester diol;

[0068] Preferably, in the component A of the above-mentioned potting glue, the polyether polyol is one or more of glycerol polyether or polyester triol with a molecular weight of less than 1000, trimethylolpropane polyether or polyester polyol, pentaerythritol polyether or polyester polyol, ethylenediamine modified polyether, sorbitol polyether, and sugar polyether;

[0069] In the component A of the above potting glue, the reinforcing agent is one or more of aluminum hydroxide, magnesium hydroxide, aluminum hypophosphite, silicon powder, calcium carbonate, and montmorillonite;

[0070] In the component A of the above potting glue, the coupling agent is one or more of 3-(methacryloyloxy)propyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-glycidyloxypropyltrimethoxysilane, γ-methacryloyloxypropyltrimethoxysilane, and diamino-functional silane;

[0071] In the component A of the above potting glue, the dewatering agent is aluminosilicate;

[0072] In the component A of the above potting glue, the thixotropic agent is one or more of fumed silica and organic bentonite.

[0073] In the component A and component B of the above potting glue, the catalyst is one or more of dibutyltin dilaurate, stannous octoate, bismuth isooctanoate, bismuth laurate, bismuth neodecanoate, zinc isooctanoate, and zinc neodecanoate;

[0074] In the component A and component B of the above potting glue, the diluent is one or more of dibutyl phthalate, di(2-ethylhexyl) phthalate, diisononyl phthalate, tri(2-chloropropyl) phosphate, and triethyl phosphate.

[0075] Preferably, in the component B of the above-mentioned potting glue, the isocyanate is one or more of toluene diisocyanate, diphenylmethane diisocyanate, isophorone diisocyanate, p-phenylene diisocyanate, 1,5-diisocyanatonaphthalene, modified liquefied MDI, polymeric MDI, MDI dimer, TDI dimer, MDI trimer, and TDI trimer z;

[0076] In the component B of the above-mentioned potting glue, the terminal isocyanate-based polyurethane prepolymer is produced by reacting a diol with a molecular weight of 1000 to 3000 with an isocyanate, and the mass fraction of the NCO content is controlled to be 10 to 25%;

[0077] Preferably, the diol in the above-mentioned terminal isocyanate polyurethane prepolymer is one or more of polypropylene glycol, polyethylene glycol, polyethylene adipate diol, polyneopentyl adipate diol, and polyhexamethylene dimer diol; the isocyanate in the terminal isocyanate polyurethane prepolymer is one or more of toluene diisocyanate, diphenylmethane diisocyanate, isophorone diisocyanate, p-phenylene diisocyanate, 1,5-diisocyanatonaphthalene, modified liquefied MDI, polymerized MDI, MDI dimer, TDI dimer, MDI trimer, and TDI trimer.

[0078] Preferably, in the above-mentioned potting glue component B, the isocyanate-terminated bio-based polyol prepolymer is produced by the reaction of bio-based polyol and isocyanate, and the mass fraction of NCO content is controlled to be 10-25%;

[0079] Preferably, in the above-mentioned isocyanate-based bio-based polyol prepolymer, the bio-based polyol is one or more of soybean oil, castor oil, palm oil, aromatic-modified castor oil, and aromatic-modified soybean oil; the isocyanate in the terminal isocyanate-based bio-based polyol prepolymer is one or more of toluene diisocyanate, diphenylmethane diisocyanate, isophorone diisocyanate, p-phenylene diisocyanate, 1,5-diisocyanatonaphthalene, modified liquefied MDI, polymerized MDI, MDI dimer, TDI dimer, MDI trimer, and TDI trimer.

[0080] Preferably, in component B of the above-mentioned potting glue, the isocyanate silane coupling agent is one or more of isocyanate propyl trimethoxy silane, isocyanate propyl triethoxy silane, isocyanate methyl trimethoxy silane, isocyanate methyl triethoxy silane, isocyanate propyl dimethoxy silane, isocyanate cyclopentyl trimethoxy silane, and isocyanate phenyl trimethoxy silane.

[0081] In the component B of the above potting glue, the water absorbent is p-toluenesulfonyl isocyanate.

[0082] The embodiment of the present invention also provides a method for preparing the above-mentioned high-strength and high-temperature resistant polyurethane structural potting adhesive for power battery caulking, comprising the following steps:

[0083] According to the above formulas of component A and component B, the constituent raw materials of component A and component B are respectively taken, and the raw materials of component A and component B are respectively mixed evenly to obtain component A and component B, and the prepared component A and component B are combined and used in a mass ratio of 1:1 to obtain a high-strength and high-temperature resistant polyurethane structural potting adhesive for power battery filling.

[0084] Preferably, the method for preparing the isocyanate-terminated prepolymer comprises:

[0085] Heat the diol to 110-120°C, stir and evacuate at the same time, dehydrate for 1-3 hours, cool to below 50°C, fill with nitrogen, add isocyanate at a ratio of 10-25% of theoretical NCO content, heat to 65-90°C, continue stirring to react for 1-3 hours, until the titrated NCO content no longer changes, end the reaction, cool to room temperature, and obtain a terminal isocyanate prepolymer.

[0086] The method for preparing the above-mentioned isocyanate-terminated bio-based polyol prepolymer comprises:

[0087] The bio-based polyol is heated to 110-120°C, stirred and vacuumed, dehydrated for 1-3 hours, cooled to below 50°C, filled with nitrogen, and isocyanate is added at a ratio of 10-25% of the theoretical NCO content. The temperature is raised to 65-90°C, and the reaction is stirred for 1-3 hours until the titrated NCO content no longer changes, and the reaction is terminated. The bio-based polyol prepolymer is cooled to room temperature to obtain an isocyanate-terminated bio-based polyol prepolymer.

[0088] In summary, the embodiments of the present invention have at least the following advantages:

[0089] (I) Environmental protection and performance improvement (bio-based polyols): By adding an appropriate amount of bio-based polyols to component A, which are natural and biodegradable, the dependence on petrochemical resources is significantly reduced, and it can meet increasingly stringent environmental regulations; bio-based polyols have a molecular rigid structure, and the aromatic ring skeleton gives polyurethane a higher modulus and strength, and has hydrophobic properties, greatly improving the tensile strength, shear strength and aging properties. At the same time, the flexible aliphatic chain segment can significantly improve the flexibility and impact resistance of polyurethane. Thereby increasing the system modulus and high temperature performance.

[0090] (II) Improve modulus, strength and adhesion (aromatic ring modified polyol): By adding an appropriate amount of aromatic ring modified polyol to component A, the polyol has multiple active groups, which react with isocyanate to form a polyurethane network with high cross-linking density, improve the modulus and high temperature resistance, and enhance the adhesion between polyurethane and the substrate. The aromatic ring gives the material higher rigidity and high temperature stability, while enhancing the mechanical strength of the potting compound, and the phenolic group and high nitrogen content group can improve the flame retardant performance.

[0091] (III) Forming a cross-linked network and improving performance (polyols): By adding an appropriate amount of polyols to component A, the polyols have multiple hydroxyl groups, so that a dense cross-linked network is formed after the polyurethane is cured, thereby improving the modulus and high temperature resistance, and increasing the adhesion between the polyurethane and the substrate.

[0092] (IV) Enhance system performance (isocyanate-terminated bio-based polyol): By adding an appropriate amount of isocyanate-terminated bio-based polyol to component B, the bio-based polyol has a molecular rigid structure, and the aromatic ring skeleton gives the polyurethane a higher modulus and strength. In addition, the bio-based polyol has a high functionality, which can increase the cross-linking density, form a denser network structure, and greatly improve the tensile strength and shear strength; at the same time, the flexible aliphatic chain segment can significantly improve the flexibility and impact resistance of the polyurethane. Thus, the system modulus and high temperature performance are increased.

[0093] (V) Improving moisture and heat resistance and adhesion (isocyanate silane coupling agent): By adding an appropriate amount of isocyanate silane coupling agent to component B, an interpenetrating cross-linked network structure can be formed, which can block the entry of water vapor, improve moisture and heat aging resistance, and effectively improve the bonding strength to PET, PC and metal substrates.

[0094] Compared with the prior art, the present invention has at least the following beneficial effects:

[0095] (1) High modulus, storage modulus ≥30MPa at 60°C, applied to power battery PACK adhesive with excellent high temperature resistance.

[0096] (2) High strength: the bulk tensile strength at 25°C is ≥30MPa, and the bulk tensile strength at 60°C is ≥8MPa. For substrates such as PET, PC, aluminum alloy, and steel, the 25°C bonding shear strength is ≥10MPa, and the 60°C bonding shear strength is ≥5MPa, ensuring the adhesion, safety, and reliability of the power battery.

[0097] (3) Excellent resistance to moisture and heat aging. After 1000h of double 85 aging, the tensile strength and shear strength decayed by less than 20%.

[0098] In order to more clearly demonstrate the technical solution and technical effects provided by the present invention, the solution provided by the embodiment of the present invention is described in detail with specific embodiments below.

[0099] Example 1

[0100] This embodiment provides a high-strength and high-temperature resistant polyurethane structural potting adhesive for power battery caulking, and the preparation method thereof includes:

[0101] The amount of each component is calculated by weight;

[0102] Preparation of the terminal isocyanate polyurethane prepolymer used for component B: Take 50 parts of polypropylene glycol with a molecular weight of 1000, stir and heat to 120°C, maintain vacuum to remove water for 2 hours, cool to 45°C, fill with nitrogen, add 65 parts of liquefied MDI, slowly heat to 75°C, stir and react for 3 hours, cool to room temperature to obtain an isocyanate silicone polyurethane prepolymer.

[0103] Preparation of the terminal isocyanate bio-based polyol prepolymer used for component B: Take 50 parts of aromatic castor oil, stir and heat to 120°C, maintain vacuum to remove water for 2 hours, cool to 40°C, fill with nitrogen, add 80 parts of liquefied MDI, slowly heat to 75°C, stir and react for 2 hours, cool to room temperature to obtain the terminal isocyanate bio-based polyol prepolymer.

[0104] Preparation of component A: Take 40 parts of castor oil polyol, 20 parts of bisphenol A polyether polyol with a molecular weight of 3000, 20 parts of glycerol polyether triol with a molecular weight of 300, 0.003 parts of dibutyltin dilaurate, 15 parts of aluminum hydroxide, 5 parts of silicon micropowder, 2 parts of 3-(methacryloyloxy)propyltrimethoxysilane, and 0.5 parts of gas silicon, disperse and stir evenly, and obtain component A after stirring for 1.5 hours.

[0105] Preparation of component B: Take 15 parts of the isocyanate-terminated polyurethane prepolymer prepared in this example, 68 parts of the isocyanate-terminated bio-based polyol prepolymer prepared in this example, 10 parts of isocyanatepropyltrimethoxysilane, 0.5 parts of tris(2-chloropropyl) phosphate, and 0.2 parts of p-toluenesulfonyl isocyanate, disperse and stir evenly, and obtain component B after stirring for 1 hour.

[0106] Example 2

[0107] This embodiment provides a high-strength and high-temperature resistant polyurethane structural potting adhesive for power battery caulking, and the preparation method thereof includes:

[0108] The amount of each component is calculated by weight;

[0109] Preparation of the isocyanate-terminated bio-based polyol prepolymer used for component B: Take 30 parts of castor oil and 20 parts of aromatic castor oil, stir and heat to 120°C, maintain vacuum to remove water for 2 hours, cool to 40°C, fill with nitrogen, add 50 parts of liquefied MDI and 20 parts of isophorone diisocyanate, slowly heat to 80°C, stir and react for 3 hours, and cool to room temperature to obtain the isocyanate-terminated bio-based polyol prepolymer.

[0110] Prepare component A: take 15 parts of castor oil polyol, 10 parts of aromatic ring modified soybean oil, 30 parts of 4,4'-diaminodiphenylmethane modified polyether with a molecular weight of 2000, 25 parts of pentaerythritol polyether with a molecular weight of 1000, 0.02 parts of bismuth isooctanoate, 18 parts of aluminum hypophosphite, 1.5 parts of diamino functional silane, and 1 part of gas silicon, disperse and stir evenly, and obtain component A after stirring for 1.5 hours.

[0111] Prepare component B: 92 parts of the isocyanate-terminated bio-based polyol prepolymer prepared in this example, 10 parts of isocyanatepropyltrimethoxysilane, 0.03 parts of bismuth isooctanoate, 1 part of dibutyl phthalate, and 0.25 parts of p-toluenesulfonyl isocyanate, disperse and stir evenly, and obtain component B after stirring for 1 hour.

[0112] Example 3

[0113] This embodiment provides a high-strength and high-temperature resistant polyurethane structural potting adhesive for power battery caulking, and the preparation method thereof includes:

[0114] The amount of each component is calculated by weight;

[0115] Preparation of the terminal isocyanate bio-based polyol prepolymer used for component B: Take 50 parts of castor oil, stir and heat to 120°C, maintain vacuum to remove water for 2 hours, cool to 50°C, fill with nitrogen, add 40 parts of liquefied MDI and 35 parts of 1,5-diisocyanatonaphthalene, slowly heat to 85°C, stir and react for 3 hours, cool to room temperature to obtain the terminal isocyanate bio-based polyol prepolymer.

[0116] Prepare component A: take 35 parts of aromatic castor oil polyol, 20 parts of melamine-modified aromatic polyol with a molecular weight of 2000, 35 parts of 400 glycerol polyether triol, 0.02 parts of bismuth isooctanoate, 5 parts of aluminum hydroxide, 12 parts of silicon powder, 2 parts of 3-(methacryloyloxy)propyltrimethoxysilane, 2 parts of triethyl phosphate, and 1 part of gas silicon, disperse and stir evenly, and obtain component A after stirring for 1.5 hours.

[0117] Prepare component B: 95 parts of isocyanate-based bio-based polyol prepolymer, 10 parts of isocyanate-based methyltrimethoxysilane, 1 part of triethyl phosphate, and 0.2 parts of p-toluenesulfonyl isocyanate, disperse and stir evenly, and obtain component B after stirring for 1 hour.

[0118] Example 4

[0119] This embodiment provides a high-strength and high-temperature resistant polyurethane structural potting adhesive for power battery caulking, and the preparation method thereof includes:

[0120] The amount of each component is calculated by weight;

[0121] Preparation of the terminal isocyanate bio-based polyol prepolymer used for component B: Take 45 parts of castor oil and 5 parts of aromatic castor oil, stir and heat to 120°C, maintain vacuum to remove water for 2 hours, cool to 40°C, fill with nitrogen, add 50 parts of liquefied MDI and 30 parts of 1,5-diisocyanatonaphthalene, slowly heat to 80°C, stir and react for 3 hours, cool to room temperature to obtain the terminal isocyanate bio-based polyol prepolymer.

[0122] Prepare component A: take 25 parts of aromatic castor oil polyol, 15 parts of palm oil, 30 parts of bisphenol A polyether polyol with a molecular weight of 3000, 15 parts of 400 glycerol polyether triol, 0.03 parts of bismuth isooctanoate, 16 parts of aluminum hydroxide, 2 parts of 3-(methacryloyloxy)propyltrimethoxysilane, and 0.8 parts of gas silicon, disperse and stir evenly, and obtain component A after stirring for 1.5 hours.

[0123] Prepare component B: 100 parts of isocyanate-based bio-based polyol prepolymer, 10 parts of isocyanate-based methyltrimethoxysilane, 1 part of triethyl phosphate, and 0.2 parts of p-toluenesulfonyl isocyanate, disperse and stir evenly, and obtain component B after stirring for 1 hour.

[0124] Performance Test:

[0125] The high-strength and high-temperature resistant polyurethane structural potting glue for power battery caulking prepared in the above embodiments is used in combination with component A and component B in a mass ratio of 1:1. The tensile strength, shear strength, modulus, and flame retardancy at room temperature of 60°C are tested, as well as the tensile strength and shear strength after double 85 aging for 1000h. Untreated aluminum alloy and PET are selected as the substrates. The test results are shown in Table 1.

[0126] Table 1 shows the performance test results of each embodiment.

[0127]

[0128]

[0129] It can be seen from the test result data in Table 1 above that the high-strength and high-temperature resistant polyurethane structural potting glue for power battery caulking of the present invention has a high modulus, a storage modulus of ≥30MPa at 60°C, excellent tensile strength, good shear strength for untreated Al and PET, and flame retardant properties that can reach the flame retardant level. After double 85 aging for 1000h, the attenuation is less than 20%, which can effectively ensure the stable performance of the power battery under complex operating conditions, improve its adhesion, safety and reliability, and meet the demand for high-performance potting materials for power battery packaging.

[0130] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by any technician familiar with the technical field within the technical scope disclosed in the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims. The information disclosed in the background technology section of this article is only intended to deepen the understanding of the overall background technology of the present invention, and should not be regarded as an admission or in any form that the information constitutes prior art known to those skilled in the art.

Claims

1. A high-strength and high-temperature resistant polyurethane structural potting adhesive for power battery caulking, characterized in that: include: Component A and component B, wherein component A and component B are used in a mass ratio of 1:1, and the functional group molar ratio of component A to component B is: NCO:OH=1.05:1-1.5:1; The component A is composed of the following raw materials in parts by mass: 15-50 parts of bio-based polyol, 15-50 parts of aromatic ring modified polyol, 10-40 parts of polyether polyol, 0.001-0.1 parts of catalyst, 5-30 parts of reinforcing agent, 0.001-10 parts of diluent, 0.001-5 parts of coupling agent, 0.001-5 parts of dehydrating agent and 0.001-5 parts of thixotropic agent; The component B is composed of the following raw materials in parts by mass: 0.001 to 50 parts of isocyanate, 0.001 to 60 parts of isocyanate-terminated polyurethane prepolymer, 30 to 75 parts of isocyanate-terminated bio-based polyol prepolymer, 0.001 to 30 parts of isocyanate-based silane coupling agent, 0.001 to 0.1 parts of catalyst, 0.001 to 10 parts of diluent and 0.001 to 0.3 parts of water absorbent.

2. The high-strength and high-temperature resistant polyurethane structural potting adhesive for power battery caulking according to claim 1, characterized in that: In the component A, the bio-based polyol is one or more of soybean oil, castor oil, palm oil, aromatic ring-modified castor oil, and aromatic ring-modified soybean oil; The aromatic ring modified polyol is one or more of bisphenol A modified polyether diol, polyester diol, bisphenol F modified polyether diol, 4,4'-diaminodiphenylmethane modified polyether or polyester diol, benzyl alcohol modified polyether or polyester diol, phenolic polyol, melamine modified aromatic ring polyol, phthalic anhydride polyester diol with a molecular weight of 400 to 3000; The polyether polyol is one or more of glycerol polyether or polyester triol, trimethylolpropane polyether or polyester polyol, pentaerythritol polyether or polyester polyol, ethylenediamine modified polyether, sorbitol polyether, and sugar polyether with a molecular weight of less than 1000.

3. The high-strength and high-temperature resistant polyurethane structural potting adhesive for power battery caulking according to claim 1, characterized in that: In the component A, the reinforcing agent is one or more of aluminum hydroxide, magnesium hydroxide, aluminum hypophosphite, silicon powder, calcium carbonate, and montmorillonite; The coupling agent is one or more of 3-(methacryloyloxy)propyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-glycidyloxypropyltrimethoxysilane, γ-methacryloyloxypropyltrimethoxysilane, and diamino-functional silane; The dewatering agent is aluminosilicate; The thixotropic agent is one or more of fumed silica and organic bentonite.

4. The high-strength and high-temperature resistant polyurethane structural potting adhesive for power battery caulking according to any one of claims 1 to 3, characterized in that: The catalysts in the A component and the B component are one or more of dibutyltin dilaurate, stannous octoate, bismuth isooctanoate, bismuth laurate, bismuth neodecanoate, zinc isooctanoate, and zinc neodecanoate; The diluents in the A component and the B component are one or more of dibutyl phthalate, di(2-ethylhexyl) phthalate, diisononyl phthalate, tri(2-chloropropyl) phosphate, and triethyl phosphate.

5. The high-strength and high-temperature resistant polyurethane structural potting adhesive for power battery caulking according to any one of claims 1 to 3, wherein in the component B, the isocyanate is one or more of toluene diisocyanate, diphenylmethane diisocyanate, isophorone diisocyanate, p-phenylene diisocyanate, 1,5-diisocyanatonaphthalene, modified liquefied MDI, polymerized MDI, MDI dimer, TDI dimer, MDI trimer, and TDI trimer; The isocyanate-terminated polyurethane prepolymer is produced by reacting a diol with a molecular weight of 1000 to 3000 with an isocyanate, and the mass fraction of the NCO content is 10 to 25%; The isocyanate-terminated bio-based polyol prepolymer is produced by the reaction of bio-based polyol and isocyanate, and the mass fraction of the NCO content is 10-25%.

6. The high-strength and high-temperature resistant polyurethane structural potting adhesive for power battery caulking according to claim 5, characterized in that: The diol in the isocyanate-terminated polyurethane prepolymer is one or more of polypropylene glycol, polyethylene glycol, polyethylene adipate glycol diol, polyneopentyl adipate glycol diol, and polyhexanediol dimer diol. The isocyanate in the isocyanate-terminated polyurethane prepolymer is one or more of toluene diisocyanate, diphenylmethane diisocyanate, isophorone diisocyanate, p-phenylene diisocyanate, 1,5-diisocyanatonaphthalene, modified liquefied MDI, polymeric MDI, MDI dimer, TDI dimer, MDI trimer and TDI trimer.

7. The high-strength and high-temperature resistant polyurethane structural potting adhesive for power battery caulking according to claim 5, characterized in that: The bio-based polyol in the isocyanate-terminated bio-based polyol prepolymer is one or more of soybean oil, castor oil, palm oil, aromatic ring-modified castor oil, and aromatic ring-modified soybean oil; The isocyanate in the terminal isocyanate bio-based polyol prepolymer is one or more of toluene diisocyanate, diphenylmethane diisocyanate, isophorone diisocyanate, p-phenylene diisocyanate, 1,5-diisocyanatonaphthalene, modified liquefied MDI, polymeric MDI, MDI dimer, TDI dimer, MDI trimer, and TDI trimer.

8. The high-strength and high-temperature resistant polyurethane structural potting adhesive for power battery caulking according to claim 5, characterized in that: In the B component, the isocyanate silane coupling agent is one or more of isocyanate propyl trimethoxy silane, isocyanate propyl triethoxy silane, isocyanate methyl trimethoxy silane, isocyanate methyl triethoxy silane, isocyanate propyl dimethoxy silane, isocyanate cyclopentyl trimethoxy silane, and isocyanate phenyl trimethoxy silane; The water absorbing agent is p-toluenesulfonyl isocyanate.

9. A method for preparing the high-strength and high-temperature resistant polyurethane structural potting adhesive for power battery caulking according to any one of claims 1 to 8, characterized in that: The following steps are involved: According to the formula of component A and component B described in any one of claims 1 to 8, the constituent raw materials of component A and component B are respectively taken, The raw materials of component A and the raw materials of component B are mixed evenly to obtain component A and component B, and the obtained component A and component B are mixed evenly in a mass ratio of 1:1 and then used to obtain a high-strength and high-temperature resistant polyurethane structural potting adhesive for power battery filling.

10. The method for preparing the high-strength and high-temperature resistant polyurethane structural potting adhesive for power battery caulking according to claim 9, characterized in that: The isocyanate-terminated polyurethane prepolymer in the B component is prepared in the following manner, including: The diol is heated to 110-120° C., stirred and vacuumed, dehydrated for 1-3 hours, cooled to below 50° C., filled with nitrogen, and isocyanate is added in a ratio of 10-25% of the theoretical NCO mass percentage, heated to 65-90° C., stirred and reacted for 1-3 hours, until the titrated NCO content no longer changes, the reaction is terminated, and cooled to room temperature to obtain an isocyanate-terminated polyurethane prepolymer; The isocyanate-terminated bio-based polyol prepolymer in the B component is prepared in the following manner, including: The bio-based polyol is heated to 110-120° C., stirred and vacuumed, dehydrated for 1-3 hours, cooled to below 50° C., filled with nitrogen, and isocyanate is added at a ratio of 10-25% of the theoretical NCO mass percentage. The temperature is raised to 65-90° C., and the reaction is stirred for 1-3 hours until the titrated NCO content no longer changes, and the reaction is terminated. The bio-based polyol prepolymer with terminal isocyanate group is obtained.

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