Bi-component polyurethane structural adhesive as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of polyurethane adhesives, and particularly relates to a two-component polyurethane structural adhesive as well as a preparation method and application thereof. The bi-component polyurethane structural adhesive comprises a component A and a component B which are independently stored, the component A comprises polyester polyol, polyether polyol, castor oil polyol and optional first filler, first molecular sieve, first plasticizer and first aid; the component B comprises an isocyanate compound, an isocyanate double-terminated polyurethane prepolymer and optional second filler, a second molecular sieve, a second plasticizer and a second aid; the first filler and the second filler are independently selected from filler modified by a silane coupling agent. The key of the invention lies in that polyester polyol, polyether polyol and castor oil polyol with long carbon chain structures are introduced as polyol raw materials, and a specific filler modified by a silane coupling agent is introduced, so that the obtained bi-component polyurethane structural adhesive has excellent interfacial shear strength and T peel strength at the same time.

Description

Technical Field

[0001] The present invention belongs to the technical field of polyurethane adhesives, and particularly relates to a two-component polyurethane structural adhesive, a preparation method thereof, and an application thereof. Background Art

[0002] In recent years, the global sales volume of new energy vehicles has shown explosive growth, and China has ranked first in the global new energy vehicle market share for nine consecutive years. The battery pack plays a crucial role in new energy vehicles, mainly in that it is the core of energy supply, determines the cruising range of the vehicle, affects the vehicle performance, and is particularly related to the safety of the vehicle. The battery pack has evolved from the traditional cell-module-battery pack (CMP) structure to the cell-to-pack (CTP) and pack-to-body (CTB / CTC) structures. The two-component polyurethane structural adhesive and the two-component polyurethane thermal conductive structural adhesive have played a key role in the entire development process of the battery pack, mainly in providing thermal conduction and dissipation and structural bonding functions. However, with the development of new energy vehicle design and battery pack technology, more and more customers have higher and higher requirements for the cruising range and cost of new energy vehicles. Therefore, in the preparation of battery packs, vehicle manufacturers and battery pack producers have gradually optimized in two aspects: one is to reduce the glue application area, so as to reduce the glue usage cost and at the same time reduce the weight of the battery pack to increase the cruising range; the other is to simplify the process in the battery pack preparation process, without performing additional surface treatment on substrates such as aluminum and PET used in the battery pack preparation process to achieve the purpose of cost reduction. Analyzed from the bonding principle, reducing the bonding area and avoiding surface treatment of the substrate will greatly reduce the absolute bonding strength, resulting in consequences such as glue debonding failure during the use of the cells or modules in the battery pack, which will greatly affect the safety of the vehicle. Summary of the Invention

[0003] After analyzing the forces on the two-component polyurethane structural adhesive in the application of battery packs, the inventors of the present invention found that most of the interface shear strengths of the two-component polyurethane structural adhesives widely used in the market can meet the requirement of more than 9 MPa, but the T-peel strength is basically lower than 2 N / mm or even lower than 1 N / mm. The importance of the T-peel strength in the application of battery packs has been underestimated by the industry. The main reason may be that in the case of a large glue application area, the high absolute bonding strength (high interface shear strength) masks the importance of the low T-peel strength in the application of battery packs. However, during the complex processes such as vibration, acceleration, and deceleration generated during vehicle driving, there are at least two forces, namely shear and drawing. At this time, if only the interface shear strength of the adhesive is emphasized while ignoring the T-peel strength, in the case of reducing the bonding area and simplifying the surface treatment of the substrate, it is easy to have glue detachment during frequent up and down vibrations, causing major safety hazards. Therefore, the purpose of the present invention is to provide a two-component polyurethane structural adhesive, its preparation method and application, aiming at the problem that the existing two-component polyurethane structural adhesives generally have high interface shear strength but low T-peel strength, resulting in easy glue detachment and failure of the battery cells or modules during use. By balancing the bonding strength and cohesive strength of the two-component polyurethane structural adhesive, the purpose of achieving both excellent interface shear strength and high T-peel strength is realized.

[0004] In the first aspect, the present invention provides a two-component polyurethane structural adhesive.

[0005] In the second aspect, the present invention provides a preparation method of the above two-component polyurethane structural adhesive.

[0006] In the third aspect, the present invention further provides an application of the above two-component polyurethane structural adhesive in the bonding of the battery pack structure of new energy vehicles.

[0007] Specifically, the two-component polyurethane structural adhesive includes component A and component B stored independently; component A includes polyester polyol, polyether polyol, castor oil polyol, and optionally a first filler, a first molecular sieve, a first plasticizer, and a first auxiliary agent; component B includes an isocyanate compound, an isocyanate group double-terminated polyurethane prepolymer, and optionally a second filler, a second molecular sieve, a second plasticizer, and a second auxiliary agent; component A includes a first filler and / or component B includes a second filler; the first filler and the second filler are each independently selected from fillers modified with a silane coupling agent; the molar ratio of the hydroxyl groups of the polyester polyol, polyether polyol, and castor oil polyol in component A to the isocyanate groups of the isocyanate compound and the isocyanate group double-terminated polyurethane prepolymer in component B is 1:(1-1.5).

[0008] The preparation method of the two-component polyurethane structural adhesive provided by the present invention includes: mixing polyester polyol, polyether polyol, castor oil polyol and optionally a first filler, a first molecular sieve, a first plasticizer, and a first auxiliary agent to obtain component A; mixing an isocyanate compound, a polyurethane prepolymer capped with isocyanate groups at both ends and optionally a second filler, a second molecular sieve, a second plasticizer, and a second auxiliary agent to obtain component B; storing the obtained component A and component B separately.

[0009] Beneficial effects: The key of the present invention lies in using a compound of polyester polyol, polyether polyol, and castor oil polyol with a long carbon chain structure as the polyol raw material, and using an isocyanate compound and a polyurethane prepolymer capped with isocyanate groups at both ends as the isocyanate raw material. On this basis, a specific filler modified with a silane coupling agent is introduced. The two-component polyurethane structural adhesive obtained thereby can well balance the adhesion strength and cohesion strength in the system, and thus has excellent interfacial shear strength and T-peel strength at the same time. The key reason may be that: due to the presence of polyols with a long carbon chain structure and a linear high-molecular polyurethane prepolymer capped with isocyanate groups at both ends, on the one hand, it is beneficial to the spreading of the polyurethane structural adhesive on the surface of the bonding substrate, improving the wettability of the structural adhesive to metal and PET substrates, and at the same time endowing the polyurethane structural adhesive with certain hydrophobicity, so as to improve the adhesion of the polyurethane structural adhesive to metal and PET substrates and ensure its certain resistance to heat and humidity and resistance to thermal shock aging performance. On the other hand, the presence of the long carbon chain structure can appropriately reduce the cohesion strength of the adhesive, so that the two-component polyurethane structural adhesive system has a good balance between adhesion strength and cohesion strength, so that it can achieve both good adhesion strength and high T-peel strength; in addition, using a silane coupling agent to treat the surface of the filler and introducing the organic functional group of the silane to the surface of the filler can not only improve the compatibility between the filler and polyurethane, but also enable the functional organic group to react with the hydroxyl group or isocyanate group in the polyurethane or improve the adhesion of the colloid to the substrate through hydrogen bonding and other effects.

[0010] In summary, the two-component polyurethane structural adhesive provided by the present invention has excellent interfacial shear strength performance and a high T-peel strength of more than 5 N / mm, providing a safer and more reliable solution for the application of the two-component polyurethane structural adhesive in battery packs. Detailed implementation manners

[0011] The two-component polyurethane structural adhesive provided by the present invention comprises component A and component B which are stored independently. Component A comprises polyester polyol, polyether polyol, castor oil polyol and optionally a first filler, a first molecular sieve, a first plasticizer and a first auxiliary agent. Component B comprises an isocyanate compound, an isocyanate group double-capped polyurethane prepolymer and optionally a second filler, a second molecular sieve, a second plasticizer and a second auxiliary agent. Component A comprises a first filler and / or component B comprises a second filler, that is, either one of component A and component B contains a filler, or both component A and component B contain a filler simultaneously. The first filler and the second filler are each independently selected from fillers modified by a silane coupling agent. The molar ratio of the hydroxyl groups of the polyester polyol, polyether polyol and castor oil polyol in component A to the isocyanate groups of the isocyanate compound and the isocyanate group double-capped polyurethane prepolymer in component B is 1:(1-1.5), such as 1:1, 1:1.1, 1:1.2, 1:1.3, 1:1.4, 1:1.5 or any value therebetween.

[0012] In the present invention, based on the total mass of the two-component polyurethane structural adhesive, the content of the polyester polyol is preferably 0.3 to 60 wt%, such as 0.3 wt%, 0.5 wt%, 1 wt%, 5 wt%, 10 wt%, 20 wt%, 30 wt%, 40 wt%, 45 wt%, 50 wt%, 60 wt% or any value therebetween; the content of the polyether polyol is preferably 0.3 to 60 wt%, such as 0.3 wt%, 0.5 wt%, 1 wt%, 5 wt%, 10 wt%, 20 wt%, 30 wt%, 40 wt%, 45 wt%, 50 wt%, 60 wt% or any value therebetween; the content of the castor oil polyol is preferably 0.3 to 60 wt%, such as 0.3 wt%, 0.5 wt%, 1 wt%, 5 wt%, 10 wt%, 20 wt%, 30 wt%, 40 wt%, 45 wt%, 50 wt%, 60 wt% or any value therebetween; the content of the isocyanate compound is preferably 0.3 to 7 wt%, such as 0.3 wt%, 0.5 wt%, 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt% or any value therebetween; the content of the isocyanate group-terminated polyurethane prepolymer is preferably 3 to 57 wt%, such as 3 wt%, 5 wt%, 8 wt%, 10 wt%, 20 wt%, 30 wt%, 40 wt%, 50 wt%, 57 wt% or any value therebetween; the total content of the first filler and the second filler is preferably 0.3 to 55 wt%, such as 0.3 wt%, 0.5 wt%, 1 wt%, 5 wt%, 10 wt%, 20 wt%, 30 wt%, 40 wt%, 50 wt%, 55 wt% or any value therebetween; the total content of the first molecular sieve and the second molecular sieve is preferably 0.3 to 10 wt%, such as 0.3 wt%, 0.5 wt%, 1 wt%, 2 wt%, 5 wt%, 8 wt%, 10 wt% or any value therebetween; the total content of the first plasticizer and the second plasticizer is preferably 0.3 to 20 wt%, such as 0.3 wt%, 0.5 wt%, 1 wt%, 5 wt%, 10 wt%, 15 wt%, 20 wt% or any value therebetween; the total content of the first auxiliary agent and the second auxiliary agent is preferably 0.3 to 10 wt%, such as 0.3 wt%, 0.5 wt%, 1 wt%, 2 wt%, 5 wt%, 8 wt%, 10 wt% or any value therebetween.

[0013] In the present invention, based on the total mass of the component A, the content of the polyester polyol is preferably 1 to 90 wt%, such as 1 wt%, 5 wt%, 10 wt%, 20 wt%, 30 wt%, 40 wt%, 50 wt%, 60 wt%, 70 wt%, 80 wt%, 90 wt% or any value therebetween; the content of the polyether polyol is preferably 1 to 90 wt%, such as 1 wt%, 5 wt%, 10 wt%, 20 wt%, 30 wt%, 40 wt%, 50 wt%, 60 wt%, 70 wt%, 80 wt%, 90 wt% or any value therebetween; the content of the castor oil polyol is preferably 1 to 90 wt%, such as 1 wt%, 5 wt%, 10 wt%, 20 wt%, 30 wt%, 40 wt%, 50 wt%, 60 wt%, 70 wt%, 80 wt%, 90 wt% or any value therebetween; the content of the first filler is preferably 1 to 50 wt%, such as 1 wt%, 5 wt%, 10 wt%, 20 wt%, 30 wt%, 40 wt%, 50 wt% or any value therebetween; the content of the first molecular sieve is preferably 1 to 15 wt%, such as 1 wt%, 2 wt%, 5 wt%, 8 wt%, 10 wt%, 12 wt%, 15 wt% or any value therebetween; the content of the first plasticizer is preferably 1 to 30 wt%, such as 1 wt%, 5 wt%, 10 wt%, 15 wt%, 20 wt%, 25 wt%, 30 wt% or any value therebetween; the content of the first auxiliary agent is preferably 1 to 15 wt%, such as 1 wt%, 2 wt%, 5 wt%, 8 wt%, 10 wt%, 12 wt%, 15 wt% or any value therebetween.

[0014] In the present invention, based on the total mass of the B component, the content of the isocyanate compound is preferably 1 to 10 wt%, such as 1 wt%, 2 wt%, 5 wt%, 8 wt%, 10 wt% or any value therebetween; the content of the isocyanate group double-terminated polyurethane prepolymer is preferably 5 to 85 wt%, such as 5 wt%, 10 wt%, 20 wt%, 30 wt%, 40 wt%, 50 wt%, 60 wt%, 70 wt%, 80 wt%, 85 wt% or any value therebetween; the content of the second filler is preferably 1 to 40 wt%, such as 1 wt%, 5 wt%, 10 wt%, 15 wt%, 20 wt%, 25 wt%, 30 wt%, 35 wt%, 40 wt% or any value therebetween; the content of the second molecular sieve is preferably 1 to 15 wt%, such as 1 wt%, 2 wt%, 5 wt%, 8 wt%, 10 wt%, 12 wt%, 15 wt% or any value therebetween; the content of the second plasticizer is preferably 1 to 30 wt%, such as 1 wt%, 5 wt%, 10 wt%, 15 wt%, 20 wt%, 25 wt%, 30 wt% or any value therebetween; the content of the second auxiliary agent is preferably 1 to 15 wt%, such as 1 wt%, 2 wt%, 5 wt%, 8 wt%, 10 wt%, 12 wt%, 15 wt% or any value therebetween.

[0015] In the present invention, the mass ratio of the A component to the B component is preferably (1 to 2):1, such as 1:1, 1.2:1, 1.3:1, 1.5:1, 1.7:1, 2:1 or any value therebetween.

[0016] In the present invention, the preparation methods of the first filler and the second filler independently preferably include: mixing an unmodified filler with a silane coupling agent in the presence of water, and the dried product is the filler obtained.

[0017] In the preparation process of the above-mentioned filler, the mass ratio of the unmodified filler to the silane coupling agent is preferably 100:(0.1 to 5), such as 100:0.1, 100:0.5, 100:1, 100:2, 100:3, 100:4, 100:5 or any value therebetween.

[0018] In the preparation process of the above-mentioned filler, the conditions of the mixing treatment preferably include: the temperature is 50 to 60 °C, such as 50 °C, 52 °C, 55 °C, 58 °C, 60 °C or any value therebetween; the rotation speed is 300 to 600 r / min, such as 300 r / min, 400 r / min, 500 r / min, 600 r / min or any value therebetween.

[0019] In the preparation process of the above-mentioned filler, the unmodified filler is preferably at least one selected from aluminum hydroxide, alumina, calcium carbonate, talc powder, quartz powder, mica powder, titanium dioxide, white carbon black, bentonite, and carbon black.

[0020] In the preparation process of the above-mentioned filler, the silane coupling agent is preferably at least one selected from amino silane coupling agents, epoxy group silane coupling agents, mercapto silane coupling agents, vinyl silane coupling agents, long carbon chain silane coupling agents, ureido silane coupling agents, and methacryloxy silane coupling agents. Specific examples thereof can be one of the silane coupling agents commonly used in the preparation of existing adhesives.

[0021] In the present invention, the number average molecular weight (Mn) of the polyester polyol is preferably 500 to 6000 g / mol, such as 500, 1000, 2000, 3000, 4000, 5000, 6000 g / mol or any value therebetween. The hydroxyl functionality of the polyester polyol is preferably 2 to 4, such as 2, 3, 4 or any value therebetween.

[0022] In the present invention, the polyester polyol is preferably at least one selected from aromatic polyester polyols, adipic acid-based polyester diols, dimer acid polyester diols, polycaprolactone polyols, and polycarbonate diols.

[0023] In the present invention, the polyether polyol is preferably at least one selected from polyoxypropylene diols, polyoxypropylene triols, polytetrahydrofuran diols, bisphenol A-modified polyether polyols, and polyoxyethylene polyols. Among them, the number average molecular weight of the polyoxypropylene diol is preferably 100 to 6000 g / mol, such as 100, 500, 1000, 2000, 3000, 4000, 5000, 6000 g / mol or any value therebetween. The number average molecular weight of the polyoxypropylene triol is preferably 250 to 6000 g / mol, such as 250, 500, 1000, 2000, 3000, 4000, 5000, 6000 g / mol or any value therebetween. The number average molecular weight of the polytetrahydrofuran diol is preferably 100 to 4000 g / mol, such as 100, 500, 1000, 2000, 3000, 4000 g / mol or any value therebetween. The number average molecular weight of the bisphenol A-modified polyether polyol is preferably 100 to 6000 g / mol, such as 100, 500, 1000, 2000, 3000, 4000, 5000, 6000 g / mol or any value therebetween. The number average molecular weight of the polyoxyethylene polyol is preferably 100 to 6000 g / mol, such as 100, 500, 1000, 2000, 3000, 4000, 5000, 6000 g / mol or any value therebetween.

[0024] In the present invention, the number-average molecular weight of the castor oil polyol is preferably 400 to 5000 g / mol, such as 400, 800, 1000, 2000, 3000, 4000, 5000 g / mol or any value therebetween. The hydroxyl functionality of the castor oil polyol is preferably 2 to 4, such as 2, 3, 4 or any value therebetween.

[0025] In the present invention, the castor oil polyol preferably includes unmodified castor oil polyol and / or modified castor oil polyol, and more preferably is modified castor oil polyol. The modified castor oil polyol may be selected from at least one of polyether-modified castor oil polyol, epoxy group-modified castor oil polyol and aromatic benzene ring-modified castor oil polyol. At this time, by further introducing a long-chain structure or an aromatic ring and an epoxy group polar structure into the polyurethane structural adhesive, it is beneficial to further improve the adhesion of the polyurethane structural adhesive to the substrate through hydrogen bonding and electrostatic interaction.

[0026] In the present invention, the type of the isocyanate compound is not limited, and it may be a type of reagent commonly used in existing polyurethane structural adhesives. Specific examples thereof include, but are not limited to: diphenylmethane-4,4'-diisocyanate (MDI), a mixture of diphenylmethane-2,2'-diisocyanate and diphenylmethane-2,4'-diisocyanate, a mixture of diphenylmethane-4,4'-diisocyanate and diphenylmethane-2,2'-diisocyanate or diphenylmethane-2,4'-diisocyanate, carbodiimide-modified MDI, polyether-modified MDI, polymethylene polyphenyl polyisocyanate, dicyclohexylmethane-4,4'-diisocyanate, isophorone diisocyanate, toluene-2,6-diisocyanate, toluene-2,4-diisocyanate, hexamethylene diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate and triphenylmethane triisocyanate.

[0027] In the present invention, the isocyanate group (NCO) content of the isocyanate group double-terminated polyurethane prepolymer is preferably 5 to 30 wt%, such as 5 wt%, 10 wt%, 15 wt%, 20 wt%, 25 wt%, 30 wt% or any value therebetween.

[0028] In the present invention, the type and source of the isocyanate group double-terminated polyurethane prepolymer are not particularly limited. It may be a polyurethane prepolymer that can be purchased on the market and has an isocyanate group content of 5 to 30 wt%, or it may be prepared according to the disclosed polyurethane prepolymer preparation method or its improved method.

[0029] In the present invention, the isocyanate group double-capped polyurethane prepolymer is preferably obtained by polymerizing a polyol raw material and an isocyanate raw material. Compared with the existing polyurethane prepolymers on the market, the polyurethane prepolymer prepared by this method has the advantages of adjustable structure design and key properties (such as hydrophobicity and adhesion to substrates). The specific preparation method is as follows: First, the polyol raw material is vacuum dehydrated until the water content is less than 300 ppm. Under nitrogen protection, the isocyanate raw material and the dehydrated polyol raw material are added for polymerization reaction until the content of isocyanate groups in the reaction system reaches 5-30 wt%, and then the reaction is stopped to obtain the isocyanate group double-capped polyurethane prepolymer.

[0030] Further, the molar ratio of the polyol raw material to the isocyanate raw material is preferably 1:(1-10), such as 1:1, 1:2, 1:5, 1:8, 1:10 or any value therebetween. The temperature of the polymerization reaction is preferably 75-85 °C, such as 75 °C, 78 °C, 80 °C, 82 °C, 85 °C or any value therebetween. The time of the polymerization reaction is preferably 1-5 h, such as 1 h, 2 h, 3 h, 4 h, 5 h or any value therebetween. The polyol raw material is preferably at least one of polyester polyol, polyether polyol, and castor oil polyol, and its hydroxyl functionality, number average molecular weight, and further defined types and specific examples are the same as those described above, and will not be elaborated here. The specific examples of the isocyanate raw material are the same as those described above, and will not be elaborated here.

[0031] Further, the detection method for the content of isocyanate groups can be a method in the prior art, such as chemical titration method, infrared spectroscopy method, spectrophotometry method, etc. The present invention preferably adopts the following method to detect the content of isocyanate groups: Weigh mg of the sample into a stoppered conical flask, add 25 mL of anhydrous toluene, cover the flask stopper, and heat and dissolve quickly on a heating plate; Pipette 25 mL of dibutylamine toluene solution (0.1 mol / L) into the stoppered conical flask, cover the stopper and shake to dissolve thoroughly, add 20 mL of isopropanol, insert the electrode and the titration head, set the titration parameters, and titrate with 0.5852 mol / L hydrochloric acid standard solution. The volume of the hydrochloric acid standard solution consumed is Vs; Without adding the sample, repeat the above operation to measure the volume of the hydrochloric acid standard solution consumed by the sample blank group as V0; Calculate the NCO content according to W(NCO%) = (V0-Vs)*0.5852*42 / (1000m)*100.

[0032] In the present invention, the first molecular sieve and the second molecular sieve are each independently preferably at least one of mordenite molecular sieve, Y zeolite molecular sieve, ZSM-5 molecular sieve, MCM-22 molecular sieve, MCM-56 molecular sieve, and Beta molecular sieve.

[0033] In the present invention, the first plasticizer and the plasticizer are each independently preferably selected from at least one of phthalate esters, aliphatic dibasic acid esters, glycol benzoates, and phosphate ester plasticizers. Specific examples thereof include, but are not limited to, at least one of dioctyl phthalate, dibutyl phthalate, dioctyl adipate, dioctyl sebacate, triphenyl phosphate, and tricresyl phosphate.

[0034] In the present invention, the first auxiliary agent and the second auxiliary agent are each independently preferably selected from at least one of color pastes, defoamers, water removers, rheological agents, leveling agents, wetting agents, coupling agents, stabilizers, and catalysts. Among them, the rheological agent is preferably fumed silica.

[0035] The present invention provides a method for preparing the above-mentioned two-component polyurethane structural adhesive. The preparation method includes: mixing polyester polyol, polyether polyol, castor oil polyol, and optionally a first filler, a first molecular sieve, a first plasticizer, and a first auxiliary agent to obtain component A; mixing an isocyanate compound, an isocyanate group double-terminated polyurethane prepolymer, and optionally a second filler, a second molecular sieve, a second plasticizer, and a second auxiliary agent to obtain component B; and storing the obtained component A and component B independently.

[0036] The present invention will be described in detail below through specific examples. The examples are intended to explain the present invention and should not be construed as a limitation of the present invention. For those not specified in the examples regarding specific techniques or conditions, the techniques or conditions described in the literature in the art or according to the product specifications are followed. For reagents or instruments without indicating the manufacturer, they are all conventional products that can be obtained through commercial purchase.

[0037] The raw materials and their sources involved in the following preparation examples, examples, and comparative examples are as follows: Polycarbonate diol, purchased from Asahi KASEI Corporation, grade PCDX-208, Mn = 2000 g / mol; Polyoxypropylene triol, purchased from Jiangsu Zhongshan Chemical Co., Ltd., grade ZSN-330, Mn = 3000 g / mol; Aromatic benzene ring modified castor oil polyol, purchased from Itochu Oil Co., Ltd., Japan, grade H-368, hydroxyl value 195 mgKOH, hydroxyl functionality 2.5; Polycaprolactone polyol, purchased from Hunan Julen Chemical Co., Ltd., grade 2204, Mn = 2000 g / mol, hydroxyl functionality 2; Bisphenol A modified polyether polyol, purchased from Arkema France, grade DIANOL 330HP, Mn = 400 g / mol, hydroxyl functionality 2; Epoxy modified castor oil polyol, purchased from Elastogran GmbH, Germany, grade Lupranol Balance 50, hydroxyl value 50 mg KOH / g, hydroxyl functionality 2.7; Dimer acid polyester diol, purchased from Croda, grade Priplast1838, Mn = 2000 g / mol; Polytetrahydrofuran diol, purchased from BASF, grade m-PolyTHF 20P, Mn = 2000 g / mol; Polyether modified castor oil polyol, purchased from Itochu Oil Co., Ltd., Japan, grade Uric H52, hydroxyl value 200 mg KOH / g, hydroxyl functionality 3; Fumed silica, purchased from CABOT Corporation, grade TS-720; Isocyanate group double-capped polyurethane prepolymer, purchased from Covestro, grade Desmodur E21, NCO content 16 wt%; Unmodified castor oil polyol, purchased from Nanjing Xinxu Industry and Trade Co., Ltd., grade Indian refined castor oil, hydroxyl value 164 mg KOH / g, hydroxyl functionality 2.7.

[0038] Preparation Example 1

[0039] This preparation example is used to illustrate the preparation of a silane coupling agent modified filler. The specific process is as follows:

[0040] First, add alumina filler powder to the stirring kettle for physical mixing for 30 min. After the temperature in the stirring kettle reaches the specified temperature of 55 °C, spray 3-aminopropyltriethoxysilane solution (concentration 5%) from the upper end of the stirring kettle every 2 min. Among them, the mass ratio of the added alumina to 3-aminopropyltriethoxysilane is 100:1. At the same time, maintain the stirring speed at 450 r / min and stir for 1 h. Finally, dry the treated powder and discharge it and let it stand for 24 h to obtain the silane coupling agent modified filler T1.

[0041] Preparation Example 2

[0042] This preparation example is used to illustrate the preparation of a silane coupling agent-modified filler, and the specific process is as follows:

[0043] First, add calcium carbonate filler powder to a stirring kettle for physical mixing for 30 min. After the temperature in the stirring kettle reaches the specified temperature of 50 °C, spray 3-(2,3-epoxypropoxy)propyltriethoxysilane solution (concentration: 5%) from the upper end of the stirring kettle every 2 min. Among them, the mass ratio of the added alumina to 3-(2,3-epoxypropoxy)propyltriethoxysilane is 100:3. At the same time, maintain the stirring speed at 300 r / min and stir for 1 h. Finally, dry the treated powder, discharge it, and let it stand for 24 h to obtain the silane coupling agent-modified filler T2.

[0044] Preparation Example 3

[0045] This preparation example is used to illustrate the preparation of a silane coupling agent-modified filler, and the specific process is as follows:

[0046] First, add quartz powder filler powder to a stirring kettle for physical mixing for 30 min. After the temperature in the stirring kettle reaches the specified temperature of 60 °C, spray 3-mercaptopropyltrimethoxysilane solution (concentration: 5%) from the upper end of the stirring kettle every 2 min. Among them, the mass ratio of the added alumina to 3-mercaptopropyltrimethoxysilane is 100:5. At the same time, maintain the stirring speed at 600 r / min and stir for 1 h. Finally, dry the treated powder, discharge it, and let it stand for 24 h to obtain the silane coupling agent-modified filler T3.

[0047] Preparation Example 4

[0048] This preparation example is used to illustrate the preparation of an isocyanate group double-capped polyurethane prepolymer, and the specific process is as follows:

[0049] First, put 10 parts by weight of polycarbonate diol, 10 parts by weight of polyoxypropylene triol, and 10 parts by weight of aromatic ring-modified castor oil polyol into a reaction kettle. Raise the temperature in the kettle to 110 °C and perform vacuum dehydration for 60 min until the water content in the kettle is less than 300 ppm. Lower the temperature in the kettle to 50 °C, add 70 parts by weight of diphenylmethane-4,4'-diisocyanate, and react with stirring under nitrogen protection while heating to 80 °C until the content of NCO in the system reaches 18.4 wt%, then stop the reaction. Lower the temperature below 50 °C, add the stabilizer phosphoric acid and stir evenly to obtain the isocyanate group double-capped polyurethane prepolymer JAZ-1.

[0050] Preparation Example 5

[0051] This preparation example is used to illustrate the preparation of an isocyanate group double-capped polyurethane prepolymer, and the specific process is as follows:

[0052] First, 10 parts by weight of polycaprolactone polyol, 10 parts by weight of bisphenol A-modified polyether polyol, and 10 parts by weight of epoxy-modified castor oil polyol are put into a reaction kettle. The temperature in the kettle is raised to 110 °C, and vacuum dehydration is carried out for 60 min until the water content in the kettle is less than 300 ppm. Then the temperature in the kettle is lowered to 50 °C, and 70 parts by weight of hexamethylene diisocyanate is added. While stirring under nitrogen protection, the temperature is raised to 80 °C for reaction. The reaction is stopped until the content of NCO in the system reaches 17.7 wt%. The temperature is lowered to below 50 °C, and stabilizer phosphoric acid is added and stirred evenly to obtain a polyurethane prepolymer JAZ-2 with isocyanate groups blocked at both ends.

[0053] Preparation Example 6

[0054] This preparation example is used to illustrate the preparation of a polyurethane prepolymer with isocyanate groups blocked at both ends. The specific process is as follows:

[0055] First, 20 parts by weight of dimer acid polyester diol, 20 parts by weight of polytetrahydrofuran diol, and 20 parts by weight of polyether-modified castor oil polyol are put into a reaction kettle. The temperature in the kettle is raised to 110 °C, and vacuum dehydration is carried out for 60 min until the water content in the kettle is less than 300 ppm. Then the temperature in the kettle is lowered to 50 °C, and 40 parts by weight of isophorone diisocyanate is added. While stirring under nitrogen protection, the temperature is raised to 80 °C for reaction. The reaction is stopped until the content of NCO in the system reaches 7.5 wt%. The temperature is lowered to below 50 °C, and stabilizer phosphoric acid is added and stirred evenly to obtain a polyurethane prepolymer JAZ-3 with isocyanate groups blocked at both ends.

[0056] Example 1

[0057] This example is used to illustrate the preparation of a two-component polyurethane structural adhesive. The specific process is as follows:

[0058] Component A: 30 parts by weight of polycarbonate diol, 30 parts by weight of polyoxypropylene triol, 30 parts by weight of aromatic ring-modified castor oil polyol, 1 part by weight of plasticizer (dibutyl phthalate), and 1 part by weight of the first auxiliary agent (including 0.2 parts of BYK-A535 from BYK Company, 0.5 parts of Dynasylan 1146 from Evonik Company, and 0.3 parts of dibutyltin dilaurate) are added to a reaction kettle for physical mixing for 30 min. Then 6 parts by weight of filler T1 obtained in Preparation Example 1, 1 part by weight of ZSM-5 molecular sieve, and 1 part by weight of fumed silica are added and mixed for 60 min. After mixing evenly and removing the vacuum, Component A is obtained and stored sealed.

[0059] Component B: Mix 5 parts by weight of diphenylmethane - 4,4'-diisocyanate, 45 parts by weight of the isocyanate - terminated polyurethane prepolymer JAZ - 1 obtained in Preparation Example 4, 15 parts by weight of a plasticizer (dibutyl phthalate), 1 part by weight of a second auxiliary agent (including 0.2 part of BYK - A535 from BYK and 0.8 part of PTSI), 32 parts by weight of the filler T1 obtained in Preparation Example 1, 1 part by weight of ZSM - 5 molecular sieve, and 1 part by weight of fumed silica for 60 - 90 min. After mixing evenly and degassing under vacuum, Component B is obtained and stored in a sealed manner.

[0060] Mix Component A and Component B evenly according to a mass ratio of 1.2:1 (the molar ratio of the hydroxyl groups in polycarbonate diol, polyoxypropylene triol, and aromatic ring - modified castor oil polyol to the isocyanate groups in diphenylmethane - 4,4'-diisocyanate and polyurethane prepolymer JAZ - 1 is 1:1.20) to obtain a two - component polyurethane structural adhesive.

[0061] Example 2

[0062] This example is used to illustrate the preparation of a two - component polyurethane structural adhesive, and the specific process is as follows:

[0063] Component A: Add 40 parts by weight of dimer acid polyester diol, 10 parts by weight of bisphenol A - modified polyether polyol, 5 parts by weight of epoxy - modified castor oil polyol, 15 parts by weight of a plasticizer (dioctyl adipate), and 1 part by weight of a first auxiliary agent (including 0.2 part of BYK - A535 from BYK, 0.5 part of Dynasylan1146 from Evonik, and 0.3 part of dibutyltin dilaurate)) into a reaction kettle for physical mixing for 30 min. Then add 27 parts by weight of the filler T2 obtained in Preparation Example 2, 1 part by weight of Y zeolite molecular sieve, and 1 part by weight of fumed silica and mix for 60 min. After mixing evenly and degassing under vacuum, Component A is obtained and stored in a sealed manner.

[0064] Component B: Mix 10 parts by weight of hexamethylene diisocyanate, 20 parts by weight of the isocyanate - terminated polyurethane prepolymer JAZ - 2 obtained in Preparation Example 2, 27 parts by weight of a plasticizer (dioctyl adipate), 1 part by weight of a second auxiliary agent (including 0.2 part of BYK - A535 from BYK and 0.8 part of PTSI)), 40 parts by weight of the filler T2 obtained in Preparation Example 1, 1 part by weight of Y zeolite molecular sieve, and 1 part by weight of fumed silica for 60 - 90 min. After mixing evenly and degassing under vacuum, Component B is obtained and stored in a sealed manner.

[0065] Mix Component A and Component B evenly according to a mass ratio of 1.5:1 (the molar ratio of the hydroxyl groups in dimer acid polyester diol, bisphenol A - modified polyether polyol, and epoxy - modified castor oil polyol to the isocyanate groups in hexamethylene diisocyanate and polyurethane prepolymer JAZ - 2 is 1:1.43) to obtain a two - component polyurethane structural adhesive.

[0066] Example 3

[0067] This example is used to illustrate the preparation of a two-component polyurethane structural adhesive, and the specific process is as follows:

[0068] Component A: Add 80 parts by weight of polycaprolactone polyol, 5 parts by weight of polytetrahydrofuran diol, 5 parts by weight of polyether-modified castor oil polyol, 5 parts by weight of plasticizer (triphenyl phosphate), and 1 part by weight of the first auxiliary agent (including 0.2 parts of BYK-A535 from BYK, 0.5 parts of Dynasylan 1146 from Evonik, and 0.3 parts of dibutyltin dilaurate)) into the reaction kettle for physical mixing for 30 min, then add 2 parts by weight of the filler T3 obtained in Preparation Example 3, 1 part by weight of MCM-22 molecular sieve, and 1 part by weight of fumed silica and mix for 60 min. After mixing evenly and degassing, Component A is obtained and stored sealed.

[0069] Component B: Add 2 parts by weight of isophorone diisocyanate, 85 parts by weight of the isocyanate group double-capped polyurethane prepolymer JAZ-3 obtained in Preparation Example 3, 1 part by weight of plasticizer (triphenyl phosphate), 1 part by weight of the second auxiliary agent (including 0.2 parts of BYK-A535 from BYK and 0.8 parts of PTSI), 9 parts by weight of the filler T3 obtained in Preparation Example 1, 1 part by weight of MCM-22 molecular sieve, and 1 part by weight of fumed silica and mix for 60 - 90 min. After mixing evenly and degassing, Component B is obtained and stored sealed.

[0070] Mix Component A and Component B evenly according to a mass ratio of 1.2:1 (the molar ratio of the hydroxyl groups in polycaprolactone polyol, polytetrahydrofuran diol, and polyether-modified castor oil polyol to the isocyanate groups in isophorone diisocyanate and polyurethane prepolymer JAZ-3 is 1:1.37) to obtain a two-component polyurethane structural adhesive.

[0071] Example 4

[0072] This example is used to illustrate the preparation of a two-component polyurethane structural adhesive, and the specific process is as follows:

[0073] Component A: Add 5 parts by weight of polycaprolactone polyol, 80 parts by weight of polytetrahydrofuran diol, 5 parts by weight of polyether-modified castor oil polyol, 5 parts by weight of plasticizer (triphenyl phosphate), and 1 part by weight of the first auxiliary agent (including 0.2 parts of BYK-A535 from BYK, 0.5 parts of Dynasylan 1146 from Evonik, and 0.3 parts of dibutyltin dilaurate)) into the reaction kettle for physical mixing for 30 min, then add 2 parts by weight of the filler T3 obtained in Preparation Example 3, 1 part by weight of MCM-22 molecular sieve, and 1 part by weight of fumed silica and mix for 60 min. After mixing evenly and degassing, Component A is obtained and stored sealed.

[0074] Component B: Mix 5 parts by weight of isophorone diisocyanate, 50 parts by weight of the isocyanate group double-capped polyurethane prepolymer JAZ-3 obtained in Preparation Example 3, 20 parts by weight of a plasticizer (triphenyl phosphate), 3 parts by weight of a second auxiliary agent (including 0.2 part of BYK-A535 from BYK and 0.8 part of PTSI), 15 parts by weight of the filler T3 obtained in Preparation Example 1, 2 parts by weight of MCM-22 molecular sieve and 5 parts by weight of fumed silica for 60 - 90 min. After mixing evenly and degassing, Component B is obtained and stored sealed.

[0075] Mix Component A and Component B evenly according to a mass ratio of 1:1 (the molar ratio of the hydroxyl groups in polycaprolactone polyol, polytetrahydrofuran diol, and polyether-modified castor oil polyol to the isocyanate groups in isophorone diisocyanate and polyurethane prepolymer JAZ-3 is 1:1.31) to obtain a two-component polyurethane structural adhesive.

[0076] Example 5

[0077] This example is used to illustrate the preparation of a two-component polyurethane structural adhesive, and the specific process is as follows:

[0078] Component A: Add 5 parts by weight of polycaprolactone polyol, 25 parts by weight of polytetrahydrofuran diol, 60 parts by weight of polyether-modified castor oil polyol, 5 parts by weight of a plasticizer (triphenyl phosphate) and 1 part by weight of a first auxiliary agent (specifically 0.2 part of BYK-A535 from BYK, 0.5 part of Dynasylan 1146 from Evonik and 0.3 part of dibutyltin dilaurate) to a reaction kettle for physical mixing for 30 min. Then add 2 parts by weight of the filler T3 obtained in Preparation Example 3, 1 part by weight of MCM-22 molecular sieve and 1 part by weight of fumed silica and mix for 60 min. After mixing evenly and degassing, Component A is obtained and stored sealed.

[0079] Component B: Mix 7 parts by weight of isophorone diisocyanate, 50 parts by weight of the isocyanate group double-capped polyurethane prepolymer JAZ-3 obtained in Preparation Example 1, 15 parts by weight of a plasticizer (triphenyl phosphate), 1 part by weight of a second auxiliary agent (specifically 0.2 part of BYK-A535 from BYK and 0.8 part of PTSI), 25 parts by weight of the filler T3 obtained in Preparation Example 1, 1 part by weight of MCM-22 molecular sieve and 1 part by weight of fumed silica for 60 - 90 min. After mixing evenly and degassing, Component B is obtained and stored sealed.

[0080] Mix Component A and Component B evenly according to a mass ratio of 1:1 (the molar ratio of the hydroxyl groups in polycaprolactone polyol, polytetrahydrofuran diol, and polyether-modified castor oil polyol to the isocyanate groups in isophorone diisocyanate and polyurethane prepolymer JAZ-3 is 1:1.15) to obtain a two-component polyurethane structural adhesive.

[0081] Example 6

[0082] This example is used to illustrate the preparation of a two-component polyurethane structural adhesive, and the specific process is as follows:

[0083] Prepare the two-component polyurethane structural adhesive according to the method of Example 1. The difference is that the isocyanate group double-terminated polyurethane prepolymer Desmodur E21 with the same mass is used to replace the isocyanate group double-terminated polyurethane prepolymer JAZ-1 obtained in Preparation Example 1, and the other conditions are the same as those in Example 1. Mix the A component and the B component evenly according to a mass ratio of 1.2:1 (the molar ratio of the hydroxyl groups in polycarbonate diol, polyoxypropylene triol, and aromatic ring-modified castor oil polyol to the isocyanate groups in diphenylmethane-4,4'-diisocyanate and polyurethane prepolymer Desmodur E21 is 1:1.07) to obtain the two-component polyurethane structural adhesive.

[0084] Example 7

[0085] This example is used to illustrate the preparation of a two-component polyurethane structural adhesive, and the specific process is as follows:

[0086] Prepare the two-component polyurethane structural adhesive according to the method of Example 1. The difference is that the unmodified castor oil polyol with the same mass is used to replace the aromatic ring-modified castor oil polyol, and the other conditions are the same as those in Example 1. Mix the A component and the B component evenly according to a mass ratio of 1.3:1 (the molar ratio of the hydroxyl groups in polycarbonate diol, polyoxypropylene triol, and unmodified castor oil polyol to the isocyanate groups in diphenylmethane-4,4'-diisocyanate and polyurethane prepolymer JAZ-1 is 1:1.23) to obtain the two-component polyurethane structural adhesive.

[0087] Comparative Example 1

[0088] This comparative example is used to illustrate the preparation of a reference two-component polyurethane structural adhesive, and the specific process is as follows:

[0089] Prepare the reference two-component polyurethane structural adhesive according to the method of Example 1. The difference is that the unmodified alumina filler with the same mass is used to replace the filler T1 obtained in Preparation Example 1, and the other conditions are the same as those in Example 1. Mix the A component and the B component evenly according to a mass ratio of 2:1 to obtain the reference two-component polyurethane structural adhesive.

[0090] Comparative Example 2

[0091] This comparative example is used to illustrate the preparation of a reference two-component polyurethane structural adhesive, and the specific process is as follows:

[0092] Prepare a reference two-component polyurethane structural adhesive according to the method of Example 1. The difference is that the same mass of polycarbonate diol is used to replace polypropylene oxide triol and aromatic ring-modified castor oil polyol, and the other conditions are the same as those in Example 1. Mix the A component and the B component evenly according to a mass ratio of 2:1 to obtain a reference two-component polyurethane structural adhesive.

[0093] Comparative Example 3

[0094] This comparative example is used to illustrate the preparation of a reference two-component polyurethane structural adhesive, and the specific process is as follows:

[0095] Prepare a reference two-component polyurethane structural adhesive according to the method of Example 1. The difference is that the same mass of polypropylene oxide triol is used to replace polycarbonate diol and aromatic ring-modified castor oil polyol, and the other conditions are the same as those in Example 1. Mix the A component and the B component evenly according to a mass ratio of 2:1 to obtain a reference two-component polyurethane structural adhesive.

[0096] Comparative Example 4

[0097] This comparative example is used to illustrate the preparation of a reference two-component polyurethane structural adhesive, and the specific process is as follows:

[0098] Prepare a reference two-component polyurethane structural adhesive according to the method of Example 1. The difference is that the same mass of aromatic ring-modified castor oil polyol is used to replace polypropylene oxide triol and polycarbonate diol, and the other conditions are the same as those in Example 1. Mix the A component and the B component evenly according to a mass ratio of 2:1 to obtain a reference two-component polyurethane structural adhesive.

[0099] Test Example

[0100] Perform performance tests on the interface shear strength and T-peel strength of the two-component polyurethane structural adhesives prepared in the above examples and comparative examples according to the following method, and the obtained results are shown in Table 1.

[0101] (1) Interface shear strength test: Coat the two-component polyurethane structural adhesives obtained in the above examples and comparative examples on 3003 aluminum sheets respectively, lap and press them with 3003 aluminum sheets to make test samples. The bonding area is 25.0 mm × 12.5 mm, and ensure that the thickness of the adhesive layer is 0.2 mm. The test samples are completed under the conditions of a temperature of 25 ± 2 °C and a humidity of 50 ± 10% RH. Then, for the completely cured samples, use a universal testing machine to pull the two sheets in opposite directions at room temperature, and record the measured force value as strength (MPa), which is the bonding strength when the sample is just made.

[0102] (2) T - peel strength test: The test is carried out according to the method in Standard GB 2791 - 1995. The size of the flexible material sample is 200 mm * 25 mm, and the thickness is ≤ 3 mm. Glue is applied across the entire width of the adherend of the flexible material, with the glue application length being 150 mm and the glue application thickness being 1 mm. The flexible material bonded part and the adherend are bonded and cured under the conditions of a temperature of 25 ± 2 °C and a humidity of 50 ± 10% RH to obtain a flexible test piece. The unbonded part of the flexible test piece is symmetrically clamped in the upper and lower clamps, and the clamped part cannot slip. Start the testing machine to separate the clamps at a speed of 100 mm / min. The peel length of the flexible test piece should be at least 125 mm. Record and plot the peel load curve, and calculate the average T - peel strength by dividing the average force within the length of 25 - 125 mm by the bond width.

[0103] T - peel strength test after 1000 h of damp heat aging: After aging the flexible test piece prepared according to the above - mentioned method for 1000 h under the conditions of 85 °C and a humidity of 85% RH, test it according to the above - mentioned method. Record and plot the peel load curve, and calculate the average T - peel strength after 1000 h of damp heat aging by dividing the average force within the length of 25 - 125 mm by the bond width.

[0104] Table 1

[0105]

[0106] It can be seen from the results in Table 1 that compared with Comparative Examples 1 - 4, the two - component polyurethane structural adhesives provided in Examples 1 - 7 of the present invention have excellent interfacial shear strength and T - peel strength, and still have good T - peel strength after 1000 h of damp heat aging.

[0107] Although the embodiments of the present invention have been shown and described above, it can be understood that the above - mentioned embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above - mentioned embodiments within the scope of the present invention without departing from the principles and purposes of the present invention.

Claims

1. A two-component polyurethane structural adhesive, characterized in that: The two-component polyurethane structural adhesive comprises an A component and a B component which are stored independently; the A component comprises polyester polyol, polyether polyol, castor oil polyol and optionally a first filler, a first molecular sieve, a first plasticizer and a first auxiliary agent; the B component comprises an isocyanate compound, an isocyanate-diblocked polyurethane prepolymer and optionally a second filler, a second molecular sieve, a second plasticizer and a second auxiliary agent; the A component comprises a first filler and / or the B component comprises a second filler; the first filler and the second filler are each independently selected from fillers modified by a silane coupling agent; the molar ratio of the hydroxyl groups of the polyester polyol, polyether polyol and castor oil polyol in the A component to the isocyanate groups of the isocyanate compound and the isocyanate-diblocked polyurethane prepolymer in the B component is 1:(1-1.5).

2. The two-component polyurethane structural adhesive according to claim 1, characterized in that: Based on the total mass of the two-component polyurethane structural adhesive, the content of the polyester polyol is 0.3-60wt%, the content of the polyether polyol is 0.3-60wt%, the content of the castor oil polyol is 0.3-60wt%, the content of the isocyanate compound is 0.3-7wt%, the content of the isocyanate double-terminated polyurethane prepolymer is 3-57wt%, the total content of the first filler and the second filler is 0.3-55wt%, the total content of the first molecular sieve and the second molecular sieve is 0.3-10wt%, the total content of the first plasticizer and the second plasticizer is 0.3-20wt%, and the total content of the first auxiliary agent and the second auxiliary agent is 0.3-10wt%.

3. The two-component polyurethane structural adhesive according to claim 1, characterized in that: Based on the total mass of the A component, the content of the polyester polyol is 1-90wt%, the content of the polyether polyol is 1-90wt%, the content of the castor oil polyol is 1-90wt%, the content of the first filler is 1-50wt%, the content of the first molecular sieve is 1-15wt%, the content of the first plasticizer is 1-30wt%, and the content of the first auxiliary agent is 1-15wt%; Preferably, based on the total mass of the B component, the content of the isocyanate compound is 1 to 10 wt%, the content of the isocyanate di-terminated polyurethane prepolymer is 5 to 85 wt%, the content of the second filler is 1 to 40 wt%, the content of the second molecular sieve is 1 to 15 wt%, the content of the second plasticizer is 1 to 30 wt%, and the content of the second auxiliary agent is 1 to 15 wt%.

4. The two-component polyurethane structural adhesive according to claim 1, characterized in that: The mass ratio of component A to component B is (1-2):1; Preferably, the preparation methods of the first filler and the second filler each independently include: mixing an unmodified filler with a silane coupling agent in the presence of water, and obtaining the filler by drying the product; Preferably, the mass ratio of the unmodified filler to the silane coupling agent is 100:(0.1-5); Preferably, the mixing treatment conditions include: a temperature of 50 to 60° C. and a rotation speed of 300 to 600 r / min; Preferably, the unmodified filler is selected from at least one of aluminum hydroxide, aluminum oxide, calcium carbonate, talc, quartz powder, mica powder, titanium dioxide, white carbon black, bentonite and carbon black; Preferably, the silane coupling agent is selected from at least one of an aminosilane coupling agent, an epoxysilane coupling agent, a mercaptosilane coupling agent, a vinylsilane coupling agent, a long carbon chain silane coupling agent, a urea silane coupling agent and a methacryloxy silane coupling agent.

5. The two-component polyurethane structural adhesive according to claim 1, characterized in that: The polyester polyol has a number average molecular weight of 500 to 6000 g / mol and a hydroxyl functionality of 2 to 4; Preferably, the polyester polyol is selected from at least one of aromatic polyester polyol, adipic acid polyester diol, dimer acid polyester diol, polycaprolactone polyol and polycarbonate diol; Preferably, the polyether polyol is selected from at least one of polyoxypropylene diol having a number average molecular weight of 100 to 6000 g / mol, polyoxypropylene triol having a number average molecular weight of 250 to 6000 g / mol, polytetrahydrofuran diol having a number average molecular weight of 100 to 4000 g / mol, bisphenol A modified polyether polyol having a number average molecular weight of 100 to 6000 g / mol, and polyoxyethylene polyol having a number average molecular weight of 100 to 6000 g / mol; Preferably, the castor oil polyol has a number average molecular weight of 400 to 5000 g / mol and a hydroxyl functionality of 2 to 4; Preferably, the castor oil polyol includes unmodified castor oil polyol and / or modified castor oil polyol.

6. The two-component polyurethane structural adhesive according to claim 1, characterized in that: The isocyanate compound is selected from at least one of diphenylmethane-4,4'-diisocyanate, a mixture of diphenylmethane-2,2'-diisocyanate and diphenylmethane-2,4'-diisocyanate, a mixture of diphenylmethane-4,4'-diisocyanate and diphenylmethane-2,2'-diisocyanate or diphenylmethane-2,4'-diisocyanate, carbodiimide-modified MDI, polyether-modified MDI, polymethylene polyphenyl polyisocyanate, dicyclohexylmethane-4,4'-diisocyanate, isophorone diisocyanate, toluene-2,6-diisocyanate, toluene-2,4-diisocyanate, hexamethylene diisocyanate, m-xylylene diisocyanate, p-xylylene diisocyanate and triphenylmethane triisocyanate.

7. The two-component polyurethane structural adhesive according to claim 1, characterized in that: The isocyanate content of the isocyanate-diblocked polyurethane prepolymer is 5 to 30 wt %; Preferably, the isocyanate-dicapped polyurethane prepolymer is obtained by polymerization reaction of a polyol raw material and an isocyanate raw material; Preferably, the polyol raw material is selected from at least one of polyester polyol, polyether polyol and castor oil polyol.

8. The two-component polyurethane structural adhesive according to claim 1, characterized in that: The first molecular sieve and the second molecular sieve are each independently selected from at least one of mordenite molecular sieve, Y zeolite molecular sieve, ZSM-5 molecular sieve, MCM-22 molecular sieve, MCM-56 molecular sieve and Beta molecular sieve; Preferably, the first plasticizer and the plasticizer are each independently selected from at least one of phthalates, aliphatic dibasic acid esters, benzoic acid glycol esters and phosphate ester plasticizers; Preferably, the first auxiliary agent and the second auxiliary agent are each independently selected from at least one of a color paste, a defoamer, a dewatering agent, a rheological agent, a leveling agent, a wetting agent, a coupling agent, a stabilizer and a catalyst.

9. The method for preparing the two-component polyurethane structural adhesive according to any one of claims 1 to 8, characterized in that: The preparation method comprises: mixing polyester polyol, polyether polyol, castor oil polyol and optional first filler, first molecular sieve, first plasticizer and first auxiliary agent to obtain component A; mixing isocyanate compound, isocyanate di-terminated polyurethane prepolymer and optional second filler, second molecular sieve, second plasticizer and second auxiliary agent to obtain component B; and the obtained components A and B are stored independently.

10. Use of the two-component polyurethane structural adhesive according to any one of claims 1 to 8 in the structural bonding of battery packs of new energy vehicles.

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