Two-component polyurethane composition as well as preparation method and application thereof

Abstract

The invention discloses a two-component polyurethane composition as well as a preparation method and application thereof, and relates to the technical field of high polymer materials. In the two-component polyurethane composition, the castor oil modified polyol is compounded with two different polyether polyols in the component A, two specific polyurethane prepolymers are compounded in the component B, and meanwhile, the heat-conducting filler is introduced into the component A and the component B, so that the heat-conducting property of the two-component polyurethane composition is improved, and the heat-conducting property of the two-component polyurethane composition is improved. The damp-heat aging resistance, the heat-conducting property, the elongation at break and the bonding strength of the two-component polyurethane composition are improved, and the modulus is reduced. The two-component polyurethane composition can be used as a structural adhesive, has high elongation at break, high bonding strength, high heat-conducting property, high humidity and heat resistance and low modulus after being cured, has excellent fatigue resistance and high temperature resistance, and is suitable for preparing batteries, such as battery cell fixation and adhesion of power batteries or heat dissipation of modules and liquid cooling plates.

Description

Technical Field

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

[0002] At present, during the assembly process of lithium-ion power batteries, polyurethane thermal conductive structural adhesives are widely used in cell fixing and bonding, as well as heat dissipation of modules and liquid cooling plates. With the promulgation of energy storage battery standards and the society's attention to the safety of new energy vehicle batteries, the entire power battery industry attaches particular importance to the reliability of battery packs after facing harsh conditions such as high-frequency vibration, high and low temperatures, high humidity, and stress shocks. The requirements for the substrate bonding strength, elongation at break, and elastic modulus of polyurethane thermal conductive adhesives are also getting higher and higher.

[0003] The polyurethane structural adhesive plays a role in bonding and fixing in the power battery pack. The fatigue resistance and high-temperature resistance of the adhesive layer are particularly crucial, directly affecting the thermal conductivity, aging resistance, fatigue vibration resistance, service life, and use safety of the power battery. The fatigue resistance of the polyurethane structural adhesive is determined by two performance indicators, namely elongation at break and elastic modulus. However, the existing polyurethane structural adhesives have a low elongation at break and a high modulus, making it difficult to meet the requirements for the fatigue resistance of the adhesive layer in current power battery packs. Summary of the Invention

[0004] The present invention aims to at least solve one of the above technical problems existing in the prior art. For this purpose, the object of the present invention is to provide a two-component polyurethane composition, which, through the combination of specific components, has a high elongation at break, a low modulus, and high thermal conductivity after curing.

[0005] The second aspect of the present invention lies in providing a preparation method of a two-component polyurethane composition.

[0006] The third aspect of the present invention lies in providing a two-component polyurethane structural adhesive.

[0007] The fourth aspect of the present invention lies in providing an application of a two-component polyurethane structural adhesive.

[0008] In order to achieve the above object, the technical solutions adopted by the present invention are as follows:

[0009] The first aspect of the present invention provides a two-component polyurethane composition, comprising component A and component B;

[0010] Component A includes castor oil-modified polyol, polyether polyol I, polyether polyol II, thermal conductive filler, and a first auxiliary agent; polyether polyol I is a small molecule polyether polyol; polyether polyol II is a polyether polyol containing an aliphatic chain;

[0011] Component B includes polyurethane prepolymer I, polyurethane prepolymer II, a thermal conductive filler, and a second auxiliary agent; polyurethane prepolymer I is obtained by polymerizing poly(propylene carbonate) diol and carbodiimide-modified MDI; polyurethane prepolymer II is obtained by polymerizing poly(propylene carbonate) diol and HDI trimer; both polyurethane prepolymer I and polyurethane prepolymer II are NCO-terminated polyurethane prepolymers.

[0012] In the two-component polyurethane composition of the present invention, different polyether polyols and castor oil-modified polyols are used in combination for component A. Among them, the castor oil-modified polyol itself has high hydrophobicity and can effectively improve the moisture and heat aging resistance of the thermal conductive adhesive. At the same time, small molecule polyether polyols can provide appropriate crosslinking points. When combined with polyether polyols containing aliphatic chains, the molecular chain flexibility is increased, the modulus is reduced, and when the obtained two-component polyurethane composition is used as a structural adhesive, the bonding strength to PET and metal substrates is improved.

[0013] In the present invention, specific polyurethane prepolymers are introduced into component B, mainly obtained by polymerizing carbodiimide-modified isocyanate or HDI trimer with flexible molecular chain polyols. The carbodiimide-modified isocyanate (diphenylmethane diisocyanate, MDI) prepolymer can improve the moisture and heat resistance and elongation at break; the polyurethane prepolymer synthesized from HDI (hexamethylene diisocyanate) trimer has both high strength and high elongation at break. By using the two polyurethane prepolymers in combination, the obtained two-component composition has the characteristics of moisture and heat resistance, low modulus, high elongation at break, and high bonding strength after curing.

[0014] In addition, a thermal conductive filler is introduced into both component A and component B of the present invention to improve the thermal conductivity.

[0015] Therefore, through the combination of specific components, the two-component polyurethane composition obtained in the present invention can be used as a structural adhesive and has high elongation at break, low modulus, high thermal conductivity, high moisture and heat resistance, and high bonding strength after curing, and has excellent fatigue resistance and high temperature resistance.

[0016] In some embodiments of the present invention, the thermal conductive filler is a thermal conductive filler modified with a block polyether treatment agent.

[0017] The thermal conductive filler of the present invention is further subjected to organic modification on the surface by a block polyether treatment agent, and has the following advantages compared with the silane coupling agent and ester-modified thermal conductive fillers in the current polyurethane system: it can effectively improve compatibility and significantly reduce the viscosity increase caused by high filler addition amounts; it has good heat resistance, and high-temperature baking will not cause coupling failure, greatly improving production efficiency and reducing energy consumption; the molecular chain has a relatively large polarity, and its own thermal conductivity is larger than that of general polymer organic substances, enabling the thermal conductive adhesive to have better thermal conductivity; the molecular weight is relatively large (the number-average molecular weight is generally 6500-11500), and it can participate in the curing reaction to improve the flexibility of the thermal conductive adhesive.

[0018] In some embodiments of the present invention, the block polyether treatment agent includes alcohol block polyether.

[0019] In some embodiments of the present invention, the process of modifying the block polyether treatment agent includes the following steps:

[0020] Heat the thermal conductive filler to 80-100 °C, and add the atomized block polyether treatment agent to the thermal conductive filler during stirring, and mix for 20-60 min.

[0021] In some specific embodiments of the present invention, the mass dosage of the block polyether treatment agent is 1-2% of the thermal conductive filler.

[0022] In some specific embodiments of the present invention, the heating method of the thermal conductive filler is hot air heating.

[0023] In some embodiments of the present invention, in component A, the thermal conductive filler includes two types of particles with medium particle size and small particle size; the medium particle size is D50 particle size of 10-20 μm; the small particle size is D50 particle size of 1-5 μm.

[0024] In some embodiments of the present invention, the medium particle size is D50 particle size of 13-17 μm; the small particle size is D50 particle size of 2-4 μm.

[0025] In some specific embodiments of the present invention, the medium particle size is D50 particle size of 14-16 μm; the small particle size is D50 particle size of 2-4 μm.

[0026] In some embodiments of the present invention, in component B, the thermal conductive filler includes two types of particles with large particle size and medium particle size; the large particle size is D50 particle size of 35-55 μm; the medium particle size is D50 particle size of 10-20 μm.

[0027] In some embodiments of the present invention, the large particle size is D50 particle size of 35-45 μm; the medium particle size is D50 particle size of 13-17 μm.

[0028] In some specific embodiments of the present invention, the large particle size is D50 particle size of 35 - 45 μm; the medium particle size is D50 particle size of 13 - 17 μm.

[0029] In some embodiments of the present invention, the medium particle size particles in component A and component B are the same.

[0030] In some embodiments of the present invention, the heat conductive fillers in component A and component B independently include at least one of aluminum hydroxide, alumina, magnesium oxide, and magnesium hydroxide.

[0031] In some embodiments of the present invention, in the heat conductive filler of component A, the mass ratio of the small particle size to the medium particle size particles is 1:(2 - 3).

[0032] In some embodiments of the present invention, in the heat conductive filler of component A, the mass ratio of the small particle size to the medium particle size particles is 1:(2 - 2.5).

[0033] Specifically, the mass ratio of the small particle size to the medium particle size particles can be 1:2, 1:2.1, 1:2.2, 1:2.5, or 1:3.

[0034] In some embodiments of the present invention, in the heat conductive filler of component B, the mass ratio of the large particle size to the medium particle size particles is 1:(1.5 - 2.5).

[0035] In some embodiments of the present invention, in the heat conductive filler of component B, the mass ratio of the large particle size to the medium particle size particles is 1:(1.5 - 2).

[0036] Specifically, the mass ratio of the large particle size to the medium particle size particles can be

[0037] In some embodiments of the present invention, the functionality of polyether polyol I is 2 - 4.

[0038] In some embodiments of the present invention, the number average molecular weight of polyether polyol I is 300 - 1000.

[0039] In some embodiments of the present invention, the number average molecular weight of polyether polyol I is 300 - 500. For example, it can be 300, 400, or 500.

[0040] In some embodiments of the present invention, polyether polyol II includes at least one of polypropylene glycol, polytetrahydrofuran glycol, and polyethylene glycol.

[0041] In some embodiments of the present invention, the number average molecular weight of polypropylene glycol is 1000 - 5000.

[0042] In some embodiments of the present invention, the number average molecular weight of the polytetrahydrofuran diol is 500 to 3000. For example, it can be 500, 1000, 1500, 2000 or 3000.

[0043] In some embodiments of the present invention, the number average molecular weight of the polyethylene oxide polyol is 100 to 4000.

[0044] In some embodiments of the present invention, the mass content of -NCO in the polyurethane prepolymer I is 8 to 12%.

[0045] In some embodiments of the present invention, the mass content of -NCO in the polyurethane prepolymer II is 12 to 18%.

[0046] In some embodiments of the present invention, in the process of polymerizing the polypropylene carbonate diol and the carbodiimide-modified MDI to obtain the polyurethane prepolymer I, the reaction molar ratio of -NCO to -OH is (2 to 5):1.

[0047] In some embodiments of the present invention, in the process of polymerizing the polypropylene carbonate diol and the HDI trimer to obtain the polyurethane prepolymer II, the reaction molar ratio of -NCO to -OH is (2 to 5):1.

[0048] In some embodiments of the present invention, the first auxiliary agent includes at least one of a water scavenger, an adhesion promoter, and a catalyst; the second auxiliary agent includes a water scavenger.

[0049] In some embodiments of the present invention, in the first auxiliary agent, the water scavenger includes molecular sieve activated powder, such as 4A molecular sieve activated powder; the adhesion promoter includes at least one of γ-aminopropyltriethoxysilane, γ-glycidyletheroxypropyltrimethoxysilane, and diamino silane polymer; the catalyst includes at least one of dibutyltin dilaurate, organic bismuth, and organic zinc.

[0050] In some embodiments of the present invention, in the second auxiliary agent, the water scavenger includes at least one of p-toluenesulfonyl isocyanate (TI) and triethyl orthoformate (OF).

[0051] In some embodiments of the present invention, the hydroxyl value of the castor oil-modified polyol is 170 to 200 mgKOH / g, for example, it can be 170 mgKOH / g, 180 mgKOH / g, 190 mgKOH / g or 200 mgKOH / g; the functionality of the castor oil-modified polyol is 2 to 3; the viscosity of the castor oil-modified polyol at 25 °C is 1000 to 3500 mPa·s, for example, it can be 1000 mPa·s, 1500 mPa·s, 2000 mPa·s, 3000 mPa·s or 3500 mPa·s.

[0052] In some embodiments of the present invention, the castor oil-modified polyol includes at least one of Ito H-368, Ito AC-009, BASF 805, BASF 819, A-30 of Shanghai Jingri New Materials Co., Ltd., and A4100 of Shanghai Jingri New Materials Co., Ltd.

[0053] In some embodiments of the present invention, in component A, the mass ratio of polyether polyol I to polyether polyol II is 1:(1-2).

[0054] Specifically, the mass ratio of polyether polyol I to polyether polyol II can be 1:1, 1:1.2, 1:1.3, 1:1.4, 1:1.5, 1:1.6, 1:1.8, or 1:2.

[0055] In some embodiments of the present invention, component A, by mass, includes the following components:

[0056] Castor oil-modified polyol: 10-20 parts, polyether polyol I: 8-15 parts, polyether polyol II: 5-10 parts, thermal conductive filler: 60-75 parts, first auxiliary agent: 0.51-8.3 parts;

[0057] Component B, by mass, includes the following components:

[0058] Polyurethane prepolymer I: 15-25 parts, polyurethane prepolymer II: 5-10 parts, thermal conductive filler: 60-75 parts, second auxiliary agent: 0.001-0.5 parts.

[0059] In some embodiments of the present invention, component A, by mass, includes the following components:

[0060] Castor oil-modified polyol: 10-20 parts, polyether polyol I: 8-15 parts, polyether polyol II: 5-10 parts, thermal conductive filler: 60-75 parts, water scavenger: 0-5 parts, adhesion promoter: 0.5-3 parts, catalyst 0.01-0.3 parts;

[0061] Component B, by mass, includes the following components:

[0062] Polyurethane prepolymer I: 15-25 parts, polyurethane prepolymer II: 5-10 parts, thermal conductive filler: 60-75 parts, water scavenger: 0.001-0.5 parts.

[0063] In some embodiments of the present invention, the volume ratio of component A to component B is (0.9-1.1):1.

[0064] The second aspect of the present invention provides a method for preparing the two-component polyurethane composition described in the first aspect of the present invention, comprising the following steps:

[0065] Heat and mix the castor oil-modified polyol, polyether polyol I, polyether polyol II, and thermal conductive filler in component A, dehydrate, cool down, and then add the first auxiliary agent and mix to obtain component A; mix the polyurethane prepolymer I, polyurethane prepolymer II, thermal conductive filler, and second auxiliary agent in component B to obtain component B; mix the component A and component B to obtain the two-component polyurethane composition.

[0066] In some embodiments of the present invention, the castor oil-modified polyol, polyether polyol I, polyether polyol II, and thermal conductive filler in component A are heated to 110-130 °C, stirred and dehydrated under vacuum, cooled to 40-60 °C, and then the first auxiliary agent is added.

[0067] In some embodiments of the present invention, component B is stirred and mixed under vacuum.

[0068] The third aspect of the present invention provides a two-component polyurethane structural adhesive, comprising the two-component polyurethane composition described in the first aspect of the present invention.

[0069] The fourth aspect of the present invention provides an application of the two-component polyurethane structural adhesive described in the third aspect of the present invention in the preparation of batteries.

[0070] In some embodiments of the present invention, the battery includes a power battery, and the two-component polyurethane structural adhesive is used for fixing and bonding the battery cells of the power battery, or for heat dissipation of the module and liquid cooling plate; the power battery can be a lithium-ion power battery.

[0071] Compared with the prior art, the beneficial effects of the present invention are:

[0072] (1) In the two-component polyurethane composition of the present invention, a castor oil-modified polyol is compounded with two different polyether polyols in component A, and two specific polyurethane prepolymers are compounded in component B. At the same time, a thermal conductive filler is introduced into both component A and component B, which improves the moisture and heat aging resistance and thermal conductivity of the two-component polyurethane composition, has an appropriate viscosity, improves the elongation at break and bonding strength after curing, reduces the modulus, and has excellent fatigue resistance and high temperature resistance.

[0073] (2) The preparation method of the two-component polyurethane composition of the present invention is simple to operate, has a simple process flow, and is suitable for industrial large-scale production.

[0074] (3) The two-component polyurethane composition of the present invention can be used as a structural adhesive, and after curing, it has high elongation at break, high bonding strength, high thermal conductivity, high resistance to humidity and heat, and low modulus, and is very suitable for preparing batteries, such as the core fixing and pasting of power batteries or the heat dissipation of modules and liquid cooling plates. Detailed Description of the Invention

[0075] The content of the present invention will be further described in detail through specific examples below. The raw materials, reagents or devices used in the examples and comparative examples can be obtained from conventional commercial channels or can be obtained by existing technical methods unless otherwise specified. Unless otherwise specified, the test or testing methods are all conventional methods in the art.

[0076] The descriptions of some raw materials used in the following examples and comparative examples of the present invention are as follows:

[0077] Thermal conductive filler: Commercially available aluminum hydroxide; among them, the D50 particle size of large-particle-size aluminum hydroxide is 40 μm; the D50 particle size of medium-particle-size aluminum hydroxide is 15 μm; the D50 particle size of small-particle-size aluminum hydroxide is 3 μm;

[0078] Block polyether treatment agent: Propylene glycol block polyether, commercially available;

[0079] Silane coupling agent: Commercially available;

[0080] Polyether polyol I: Shanghai Dongda Chemical DV-125N; functionality is 3, number average molecular weight is 375;

[0081] Polyether polyol II: Polytetrahydrofuran diol, number average molecular weight is 1250, BASF PolyTHF 2000;

[0082] Castor oil-modified polyol: Ito H368, hydroxyl value 195 mgKOH / g, functionality 2.5, viscosity (25 °C) 1300 mPa·s; A4100 of Shanghai Jingri New Materials Co., Ltd., hydroxyl value 170 mgKOH / g, functionality 3, viscosity (25 °C) 3500 mPa·s;

[0083] Adhesion promoter: Epoxy-based silane coupling agent (γ-glycidoxypropyltrimethoxysilane), commercially available;

[0084] Water scavenger A: 4A molecular sieve activated powder, JLH-04 of Luoyang Jianlong Weina New Materials Co., Ltd.;

[0085] Water scavenger B: Toluene sulfonyl isocyanate, Borchers TI;

[0086] Catalyst: Organic bismuth, BICAT-8 of American Leading Chemicals Company;

[0087] Carbodiimide-modified MDI: Wanhua Chemical MDI-100L;

[0088] HDI trimer: BASF Basonat HI 100ap;

[0089] Poly(propylene carbonate) diol: Commercially available.

[0090] Preparation process of NCO-terminated polyurethane prepolymer Ⅰ:

[0091] Weigh 500 g of poly(propylene carbonate) diol (number-average molecular weight 2000) and add it to a dry stirring kettle. While stirring, heat it up to 60 °C, slowly add 1376 g of carbodiimide-modified MDI, and gradually heat it up to 80 °C in a gradient of 10 °C under vacuum. Keep the temperature constant for 4 h, take samples to detect the -NCO content. When the -NCO mass content reaches the theoretical value (10%), NCO-terminated polyurethane prepolymer Ⅰ is obtained; during the preparation process, the reaction molar ratio of -NCO to -OH is 2:1.

[0092] Preparation process of NCO-terminated polyurethane prepolymer Ⅱ:

[0093] Weigh 150 g of poly(propylene carbonate) diol (number-average molecular weight 1000) and add it to a dry stirring kettle. While stirring, heat it up to 60 °C, slowly add 1850 g of HDI trimer, and gradually heat it up to 80 °C in a gradient of 10 °C under vacuum. Keep the temperature constant for 4 h, take samples to detect the -NCO content. When the -NCO mass content reaches the theoretical value (15%), NCO-terminated polyurethane prepolymer Ⅱ is obtained; during the preparation process, the reaction molar ratio of -NCO to -OH is 2:1.

[0094] The thermal conductive fillers are used after being modified. Among them, the modification method of block polyether is as follows:

[0095] Heat the thermal conductive fillers to 80 °C by hot air, add them to a high-speed mixer, dilute the block polyether treatment agent and continuously spray it into the high-speed moving thermal conductive fillers in a high-pressure atomization manner. The mass of the block polyether treatment agent is 1% of the thermal conductive fillers, and it is prepared by continuous stirring for 40 min.

[0096] The following will be described in detail with specific examples and comparative examples.

[0097] Example 1

[0098] This example provides a two-component polyurethane composition, and the formula is shown in Table 1.

[0099] The preparation method of the two-component polyurethane composition in this example includes the following steps:

[0100] Castor oil-modified polyol, polyether polyol I, polyether polyol II, and thermal conductive filler are added to a planetary kettle, heated to 120 °C, and stirred to dehydrate under vacuum. Then, the temperature is lowered to 40 - 60 °C, and water scavenger A, adhesion promoter, and catalyst are added, followed by stirring under vacuum to obtain component A of the two-component polyurethane composition.

[0101] The thermal conductive filler is added to a drying kettle, stirred at 120 °C under vacuum for 1 hour to dry the moisture. Then, the dried thermal conductive filler, NCO-terminated polyurethane prepolymer I, NCO-terminated polyurethane prepolymer II, and water scavenger B are added to a planetary kettle and stirred under vacuum to obtain component B of the two-component polyurethane composition.

[0102] When in use, component A and component B of the two-component polyurethane composition are mixed.

[0103] Examples 2 - 4

[0104] This example provides a two-component polyurethane composition. The formula is shown in Table 1, and the preparation method is the same as that in Example 1.

[0105] Example 5

[0106] This example provides a two-component polyurethane composition. The difference from Example 3 is that the dosages of the two polyurethane prepolymers in component B are adjusted. The specific formula is shown in Table 2, and the preparation method is the same as that in Example 1.

[0107] Example 6

[0108] This example provides a two-component polyurethane composition. The difference from Example 3 is that component B only contains medium-sized aluminum hydroxide. The specific formula is shown in Table 2, and the preparation method is the same as that in Example 1.

[0109] Table 1 Formulation table of the two-component polyurethane composition in Examples 1 - 6 (parts by mass)

[0110]

[0111]

[0112] Comparative Example 1

[0113] This comparative example provides a two-component polyurethane composition. The difference from Example 3 is that component A does not contain polyether polyol II. The specific formula is shown in Table 2, and the preparation method is the same as that in Example 1.

[0114] Comparative Example 2

[0115] This comparative example provides a two-component polyurethane composition, which is different from that of Example 3 in that: the component B does not contain the NCO-terminated polyurethane prepolymer II, and the specific formulation is shown in Table 2; the preparation method is the same as that of Example 1.

[0116] Comparative Example 3

[0117] This comparative example provides a two-component polyurethane composition, which is different from that of Example 3 in that: the thermally conductive filler uses a conventional commercially available silane coupling agent to modify aluminum hydroxide, and the modification method is the same as that of the block polyether treatment agent; the specific formulation is shown in Table 2; the preparation method is the same as that of Example 1.

[0118] Table 2 Formulation table of the two-component polyurethane composition of Comparative Examples 1-3 (parts by mass)

[0119]

[0120]

[0121] Result detection

[0122] Using the two-component polyurethane compositions of the examples and comparative examples as two-component polyurethane structural adhesives, components A and B are mixed (volume ratio 1:1) and cured (cured for 7 days at a temperature of 23±2°C and a relative humidity of 50±5%), and performance tests are carried out.

[0123] Viscosity (25°C, mPa·s): Tested in accordance with standard GB / T 2794-2022;

[0124] Thermal conductivity (W / (m·K)): Tested in accordance with ASTM D5470-171;

[0125] Tensile strength of the body (25°C, MPa): Tested in accordance with GB / T 528-2009;

[0126] Elongation at break (25°C, %): Tested in accordance with GB / T 528-2009;

[0127] Tensile modulus (25°C, MPa): Tested in accordance with GB / T 528-2009;

[0128] Shear strength (25°C, MPa): Tested in accordance with GB / T 7124-2008, and the bonding substrate is aluminum-aluminum (Al-Al) (3003 aluminum);

[0129] Elastic modulus (25°C, MPa): Dynamic thermomechanical analysis (DMA), frequency 1 Hz, tested in accordance with ASTM E1640-13.

[0130] The test results are shown in Table 3.

[0131] Table 3 Performance test results of two-component polyurethane compositions of examples and comparative examples as structural adhesives

[0132]

[0133] As can be seen from the results in Table 3, the two-component polyurethane composition obtained in the examples of the present invention can be used as a structural adhesive. Its viscosity is moderate, remaining in the range of 70,000 to 140,000 mPa·s. After curing, it has a high thermal conductivity of not less than 1.28 W / (m·K), a bulk tensile strength of not less than 8 MPa, an elongation at break of not less than 99%, a tensile modulus of not exceeding 225 MPa, an elastic modulus of not exceeding 460 MPa, and a shear strength of not less than 9.5 MPa. It has the characteristics of high elongation at break, low modulus, high thermal conductivity, and high bonding strength, and its comprehensive performance is excellent. In Comparative Example 1, polyether polyol II is not used and the amount of polyether polyol I is small, resulting in a low crosslinking density. In Comparative Example 2, NCO-terminated polyurethane prepolymer II and polyether polyol I are not used, and the crosslinking density is also low. The polyurethane compositions obtained from both have lower tensile strength and lower shear strength.

[0134] In summary, through the compounding of specific components, the two-component polyurethane composition of the present invention improves the moisture and heat aging resistance and thermal conductivity of the two-component polyurethane composition, has an appropriate viscosity, and after curing, the elongation at break and bonding strength are improved, the modulus is reduced, and the preparation method is simple. This two-component polyurethane composition can be used as a structural adhesive, making the cured structural adhesive have high elongation at break, high bonding strength, high thermal conductivity, high moisture and heat resistance, and low modulus, with excellent anti-fatigue performance and high-temperature resistance, and is suitable for the preparation of batteries, such as the fixing and pasting of battery cells or the heat dissipation between modules and liquid cooling plates in power batteries.

[0135] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited by the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principle of the present invention shall be equivalent replacement methods and are all included in the protection scope of the present invention.

Claims

1. A two-component polyurethane composition, characterized in that: Comprising component A and component B; The component A comprises castor oil modified polyol, polyether polyol I, polyether polyol II, thermal conductive filler and a first auxiliary agent; the polyether polyol I is a small molecule polyether polyol; the polyether polyol II is a polyether polyol containing a fatty chain; The component B comprises polyurethane prepolymer I, polyurethane prepolymer II, a thermal conductive filler and a second auxiliary agent; the polyurethane prepolymer I is obtained by polymerizing polypropylene carbonate diol and carbodiimide-modified MDI; the polyurethane prepolymer II is obtained by polymerizing polypropylene carbonate diol and HDI trimer; the polyurethane prepolymer I and polyurethane prepolymer II are both NCO-terminated polyurethane prepolymers.

2. The two-component polyurethane composition according to claim 1, characterized in that: The thermally conductive filler is a thermally conductive filler modified by a block polyether treating agent; And / or, in the component A, the thermally conductive filler comprises two types of particles, medium particle size and small particle size; the medium particle size is a D50 particle size of 10 to 20 μm; the small particle size is a D50 particle size of 1 to 5 μm; And / or, in the component B, the thermally conductive filler comprises two types of particles, large particle size and medium particle size; the large particle size is a D50 particle size of 35 to 55 μm; and the medium particle size is a D50 particle size of 10 to 20 μm.

3. The two-component polyurethane composition according to claim 2, characterized in that: In the thermally conductive filler of component A, the mass ratio of the particles with small particle size to the particles with medium particle size is 1:(2-3); And / or, in the thermally conductive filler of component B, the mass ratio of the particles with large particle size to the particles with medium particle size is 1:(1.5-2.5).

4. The two-component polyurethane composition according to claim 1, characterized in that: The functionality of the polyether polyol I is 2 to 4; and / or, the number average molecular weight of the polyether polyol I is 300 to 1000; And / or, the polyether polyol II includes at least one of polyoxypropylene glycol, polytetramethylene glycol, and polyoxyethylene polyol.

5. The two-component polyurethane composition according to claim 1, characterized in that: The mass content of -NCO in the polyurethane prepolymer I is 8 to 12%; And / or, the mass content of -NCO in the polyurethane prepolymer II is 12 to 18%.

6. The two-component polyurethane composition according to claim 1, characterized in that: The first auxiliary agent includes at least one of a dehydrating agent, an adhesion promoter, and a catalyst; and the second auxiliary agent includes a dehydrating agent.

7. The two-component polyurethane composition according to claim 6, characterized in that: The component A comprises the following ingredients by weight: Castor oil modified polyol: 10-20 parts, polyether polyol I: 8-15 parts, polyether polyol II: 5-10 parts, thermal conductive filler: 60-75 parts, dehydrating agent: 0-5 parts, adhesion promoter: 0.5-3 parts, catalyst 0.01-0.3 parts; The component B comprises the following ingredients in parts by mass: Polyurethane prepolymer I: 15-25 parts, polyurethane prepolymer II: 5-10 parts, thermal conductive filler: 60-75 parts, dewatering agent: 0.001-0.5 parts.

8. A method for preparing the two-component polyurethane composition according to any one of claims 1 to 7, characterized in that: The following steps are involved: The castor oil modified polyol, polyether polyol I, polyether polyol II and thermal conductive filler in component A are heated, mixed and dehydrated, and after cooling, the first auxiliary agent is added and mixed to obtain component A; The polyurethane prepolymer I, the polyurethane prepolymer II, the thermal conductive filler and the second auxiliary agent in the component B are mixed to obtain the component B; and the component A and the component B are mixed to obtain the two-component polyurethane composition.

9. A two-component polyurethane structural adhesive, characterized in that: The invention comprises the two-component polyurethane composition according to any one of claims 1 to 7.

10. Use of the two-component polyurethane structural adhesive according to claim 9 in the preparation of batteries.

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