A high-curing-rate sealant for new energy vehicles and a preparation method thereof

Abstract

The application discloses a high-curing-rate sealing glue for new energy vehicles and a preparation method thereof, and belongs to the technical field of adhesive preparation. The high-curing-rate sealing glue for new energy vehicles comprises components A and B. The preparation raw materials of the component A comprise a double-bond-containing polyurethane oligomer, glycerol, a magnetic sensing filler, diisodecyl phthalate, fumed silica and p-toluenesulfonyl isocyanate; and the preparation raw materials of the component B comprise an MDI type isocyanate prepolymer, a composite catalyst, heavy calcium carbonate and diisodecyl phthalate. The sealing glue has a long operable time, a fast curing rate, excellent adhesion and moisture and heat resistance.

Description

Technical Field

[0001] This invention discloses a high-curing-rate sealant for new energy vehicles and its preparation method, belonging to the field of adhesive preparation technology. Background Technology

[0002] The rapid development of the new energy vehicle industry has placed new demands on sealants used in new energy vehicles. These sealants play a crucial role in sealing and protecting key vehicle components such as battery packs, drive batteries, and electronic control units. These components require sealants with excellent adhesion, weather resistance, insulation, flexibility, and long-term reliability. Polyurethane sealants, due to their superior comprehensive performance, are widely used in this field. However, traditional polyurethane sealants, especially single-component moisture-curing types, suffer from slow curing rates. The surface drying time and deep curing time for these sealants can range from several hours to several days, impacting production efficiency. Some existing technologies use catalysts to increase the curing rate, but this often leads to significantly reduced operating time, making application difficult, or catalyst migration can affect the long-term aging performance of the product.

[0003] Prior art with publication number CN120098601A discloses a silicone sealant with high fire resistance, flame retardancy, and high mechanical properties, and its preparation method. The silicone sealant's raw material composition includes 107 silicone rubber, nano-calcium carbonate, vinyl tributanone oxime silane, methyl tributanone oxime silane, a catalyst, and modified ceramic powder in a specific weight ratio. The modified ceramic powder is obtained through a stepwise grafting reaction of a silane coupling agent and the flame retardant TBC. The silicone sealant obtained by this patent has excellent fire resistance, flame retardancy, and mechanical properties, but its curing rate is low and the production cycle is long. Prior art with publication number CN120059663A discloses a mildew-resistant silicone sealant with high curing rate and high adhesion, and its preparation method. The raw material composition of this anti-mildew silicone sealant includes α,ω-dihydroxypolydimethylsiloxane, dimethyl silicone oil, fumed silica, phenoxy resin-coated nano-calcium carbonate, modified hydroxypropyl-γ-cyclodextrin-loaded anti-mildew agent, dibutyltin dilaurate, methyltrimethoxysilane, and a specific curing accelerator in a specific weight ratio. The silicone sealant obtained by this patent maintains excellent performance with high adhesive strength, but its adhesive strength is insufficient under long-term humid and hot conditions.

[0004] As can be seen from the existing technologies described above, current sealants for new energy vehicles have the following technical defects: low curing rate, poor resistance to damp heat aging, and low bond strength. Therefore, developing a sealant for new energy vehicles with a high curing rate is of great significance to the development of new energy vehicles. Summary of the Invention

[0005] To address the above technical problems, this invention provides a high-curing-rate sealant for new energy vehicles and its preparation method, achieving the following objectives: improving the curing rate, moisture and heat resistance, and bonding strength of the sealant for new energy vehicles.

[0006] To achieve the above objectives, the following technical solution is adopted: This invention provides a high-curing-rate sealant for new energy vehicles, comprising component A and component B; the mass ratio of component A to component B is (1.3-1.5):1.

[0007] The raw material weight ratio of component A is as follows: 25-35 parts of polyurethane oligomer containing double bonds, 2-5 parts of glycerol, 22-34 parts of magnetic filler, 10-20 parts of diisodecyl phthalate, 2-5 parts of fumed silica, and 0.5-2 parts of p-toluenesulfonyl isocyanate. All the above parts are by weight.

[0008] The magnetic filler is surface-modified nano-Fe3O4, and the modifier used is γ-aminopropyltriethoxysilane; the mass ratio of γ-aminopropyltriethoxysilane to nano-Fe3O4 is 1:(10-15).

[0009] The polyurethane oligomer containing double bonds is prepared from the following raw materials: polytetrahydrofuran ether diol, isophorone diisocyanate, dibutyltin dilaurate, hydroxyethyl methacrylate, and hydroquinone.

[0010] The nano-iron oxide has a particle size of 30-40 nm and a purity of >99.5%.

[0011] The raw material weight ratio of component B is as follows: 40-60 parts of MDI type isocyanate prepolymer, 1-3 parts of composite catalyst, 25-40 parts of heavy calcium carbonate, and 5-15 parts of diisodecyl phthalate. All the above parts are by weight.

[0012] The MDI-type isocyanate prepolymer has an NCO content of 13%-15%.

[0013] The composite catalyst is obtained by mixing a delayed amine catalyst with dibutyltin dilaurate at a mass ratio of (2-4):1.

[0014] The heavy calcium carbonate has a particle size of 3-6 μm and CaCO3 ≥ 98 wt%.

[0015] The fumed silica has a particle size of 10-40 nm.

[0016] The delayed amine catalyst was prepared by reacting triethylenediamine with dimethyl carbonate in a molar ratio of 1:(1-1.05).

[0017] This invention provides a method for preparing a high-curing-rate sealant for new energy vehicles, comprising the following steps: Step 1: Preparation of polyurethane oligomers containing double bonds Dehydrated polytetrahydrofuran ether diol was mixed with isophorone diisocyanate, and dibutyltin dilaurate was added dropwise. The mixture was stirred for 2-4 hours to obtain an NCO-terminated polyurethane prepolymer. Hydroxyethyl methacrylate and hydroquinone were added dropwise to the reaction system, and the mixture was stirred for another 3-6 hours. After volatilization at elevated temperature, a polyurethane oligomer containing double bonds was obtained.

[0018] The dehydration process involves adding polytetrahydrofuran ether diol to a reactor, controlling the reactor temperature at 100-120℃, and drying for 1.5-3 hours under a vacuum of ≤-0.095MPa. The reactor is then cooled to 70-85℃.

[0019] The molecular weight of the polytetrahydrofuran ether diol is 1000-3000 Da.

[0020] The stirring reaction is carried out at a temperature of 75-85℃ and a stirring rate of 50-150 r / min.

[0021] The heating and devolatilization process involves controlling the vacuum level to ≤-0.09MPa and the temperature to 75-85℃ to remove residual monomers.

[0022] The molar ratio of polytetrahydrofuran ether diol, isophorone diisocyanate, hydroxyethyl methacrylate, hydroquinone, and dibutyltin dilaurate is 1:(1.5-1.6):(1.0-1.2):(0.005-0.01):(0.0005-0.001).

[0023] Step 2: Preparation of magnetically sensitive filler The hydrolysate of γ-aminopropyltriethoxysilane was added dropwise to a suspension of iron oxide and refluxed for 4-6 hours. The solid was collected by filtration, washed, dried, and ground to obtain a magnetic filler.

[0024] The reflux reaction is carried out at a temperature of 70-80℃.

[0025] The washing process involves rinsing the solid with anhydrous ethanol.

[0026] The drying process involves controlling the drying temperature at 70-80℃ and drying for 8-12 hours.

[0027] The mass ratio of the γ-aminopropyltriethoxysilane hydrolysate to the iron oxide suspension is 1:(10-15).

[0028] The γ-aminopropyltriethoxysilane hydrolysate is prepared by the following method: γ-aminopropyltriethoxysilane is mixed with a 45-55% ethanol solution, and the mass ratio of γ-aminopropyltriethoxysilane to ethanol solution is 1:(5-6); the mixed γ-aminopropyltriethoxysilane and ethanol solution are stirred for 15-30 minutes at a speed of 200-400 r / min to obtain the γ-aminopropyltriethoxysilane hydrolysate.

[0029] The iron oxide suspension is prepared by the following method: nano-iron oxide is dispersed in anhydrous ethanol at a mass ratio of 1:(5-7), stirring is started and stirred for 30-60 minutes at a speed of 300-600 r / min to obtain the iron oxide suspension.

[0030] Step 3: Prepare component A Polyurethane oligomers containing double bonds, glycerol, and diisodecyl phthalate were vacuum dried, and then magnetic filler, fumed silica, and p-toluenesulfonyl isocyanate were added in sequence. After stirring and degassing, component A was obtained.

[0031] The vacuum drying process involves controlling the vacuum level to ≤-0.095MPa and the temperature to 110-120℃ for 1-2 hours to remove water.

[0032] The stirring and degassing process involves a stirring speed of 300-600 r / min.

[0033] The stirring and degassing process involves controlling the vacuum level to ≤-0.095MPa to remove gas.

[0034] The stirring and degassing time is 25-45 minutes.

[0035] Step 4: Preparation of composite catalyst Dimethyl carbonate was added dropwise to a triethylenediamine solution, and the reaction was carried out at a temperature of 4-6 h to obtain a delayed-type amine catalyst. The delayed-type amine catalyst was then mixed with dibutyltin dilaurate at a mass ratio of (2-4):1 to obtain a composite catalyst.

[0036] The triethylenediamine solution is obtained by mixing triethylenediamine and anhydrous ethanol at a mass ratio of 8:(23-26).

[0037] The heating reaction is controlled at a temperature of 50-60℃.

[0038] The molar ratio of triethylenediamine to dimethyl carbonate is 1:(1-1.05).

[0039] Step 5: Prepare component B MDI-type isocyanate prepolymer was mixed evenly with diisodecyl phthalate, a composite catalyst and heavy calcium carbonate were added, the mixture was heated and stirred for 1-1.5 hours, and after vacuum degassing, the product was discharged to obtain component B.

[0040] The heating and stirring process involves controlling the rotation speed at 600-800 r / min and the stirring temperature at 40-50℃.

[0041] The vacuum degassing process involves controlling the vacuum level to ≤-0.095MPa to remove gas.

[0042] The vacuum degassing time is 25-45 minutes.

[0043] This invention also provides a method for applying a high-curing-rate sealant for new energy vehicles: Mix components A and B at a mass ratio of 1.3-1.5:1 to form a sealant. After applying the sealant to the bonding of components in new energy vehicles, place the bonded parts in an alternating magnetic field with a frequency of 50-100kHz and a magnetic field strength of 5-15kA / m for 2-5 minutes. This application method utilizes the magnetocaloric effect of the magnetically sensitive filler in the alternating magnetic field to rapidly raise the temperature, thereby accelerating the curing of the sealant.

[0044] The beneficial effects of this invention are as follows: 1. The sealant of this invention has a workable time of 34-40 minutes and a curing rate of 21-25 mm / 24h. The sealant has a tensile strength of 6.6 MPa-7.1 MPa and an elongation at break of 462%-475%, exhibiting excellent strength and toughness. The sealant also has a tensile shear strength of 3.6 MPa-3.9 MPa, and after a 300-hour damp heat test, the change rate of its tensile shear strength due to damp heat resistance is only -4.2% to -4.8%, demonstrating excellent adhesion and resistance to damp heat.

[0045] 2. This invention introduces a magnetic filler into the raw materials. After construction, an alternating magnetic field can be applied to generate heat in the magnetic filler, achieving rapid curing. After modification, the surface of Fe3O4 changes from inorganic hydrophilic to organic hydrophobic, significantly improving its compatibility with polyurethane oligomers and plasticizers. It can achieve uniform dispersion in component A, avoiding mechanical defects caused by agglomeration. During the curing process, the modified Fe3O4 particles are embedded in the cross-linked network of polyurethane, achieving the integration of "inorganic filler-organic matrix," which can improve the tensile strength and water resistance of the sealant to a certain extent.

[0046] 3. This invention introduces polyurethane oligomers containing double bonds into the raw materials. These oligomers use polytetrahydrofuran ether diol with a molecular weight of 1000-3000 Da as the soft segment, which improves toughness. Isophorone diisocyanate improves strength and weather resistance. The hydroxyl groups of hydroxyethyl methacrylate are capped with the terminal -NCO of the prepolymer, introducing a double bond structure that can be further crosslinked, which is beneficial to enhancing the cohesive strength and adhesion of the sealant during curing. Detailed Implementation

[0047] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be described in further detail below. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of the invention.

[0048] Example 1: A high-curing-rate sealant for new energy vehicles includes component A and component B; the mass ratio of component A to component B is 1.3:1.

[0049] The raw material weight ratio of component A is as follows: 25 parts of polyurethane oligomer containing double bonds, 2 parts of glycerol, 22 parts of magnetic filler, 10 parts of diisodecyl phthalate, 2 parts of fumed silica, and 0.5 parts of p-toluenesulfonyl isocyanate. All the above parts are by weight.

[0050] The raw materials for the polyurethane oligomer containing double bonds include polytetrahydrofuran ether diol, isophorone diisocyanate, hydroxyethyl methacrylate, hydroquinone, and dibutyltin dilaurate.

[0051] The magnetic filler is surface-modified nano-ferric oxide, and the modifier used is γ-aminopropyltriethoxysilane.

[0052] The raw material weight ratio of component B is as follows: 40 parts of MDI type isocyanate prepolymer, 1 part of composite catalyst, 25 parts of heavy calcium carbonate, and 5 parts of diisodecyl phthalate. All the above parts are by weight.

[0053] The composite catalyst is obtained by mixing a delayed amine catalyst with dibutyltin dilaurate at a mass ratio of 3:1.

[0054] A method for preparing a high-curing-rate sealant for new energy vehicles includes the following steps: Step 1: Preparation of polyurethane oligomers containing double bonds Dehydrated polytetrahydrofuran ether diol was mixed with isophorone diisocyanate, and dibutyltin dilaurate was added dropwise. The mixture was stirred for 2 hours to obtain an NCO-terminated polyurethane prepolymer. Hydroxyethyl methacrylate and hydroquinone were added dropwise to the reaction system, and the mixture was stirred for another 6 hours. After volatilization at elevated temperature, a polyurethane oligomer containing double bonds was obtained.

[0055] The dehydration process involves adding polytetrahydrofuran ether diol to a reactor, controlling the reactor temperature at 100°C, and drying for 3 hours under a vacuum of ≤-0.095MPa. The reactor is then cooled to 70°C.

[0056] The molecular weight of the polytetrahydrofuran ether diol is 2000 Da.

[0057] The stirring reaction was carried out at a temperature of 75°C and a stirring rate of 150 r / min.

[0058] The heating and devolatilization process involves controlling the vacuum level to ≤-0.09MPa and the temperature to 75℃ to remove residual monomers.

[0059] The molar ratio of polytetrahydrofuran ether diol, isophorone diisocyanate, hydroxyethyl methacrylate, hydroquinone, and dibutyltin dilaurate is 1:1.5:1.0:0.008:0.0005.

[0060] Step 2: Preparation of magnetically inductive filler The hydrolysate of γ-aminopropyltriethoxysilane was added dropwise to a suspension of iron oxide, and the mixture was refluxed for 6 hours. The solid was collected by filtration, washed, dried, and ground to obtain a magnetic filler.

[0061] The mass ratio of the γ-aminopropyltriethoxysilane hydrolysate to the iron tetroxide suspension is 1:10.

[0062] The γ-aminopropyltriethoxysilane hydrolysate was prepared by the following method: γ-aminopropyltriethoxysilane was mixed with a 45% ethanol solution at a mass ratio of 1:5; the mixed γ-aminopropyltriethoxysilane and ethanol solution were stirred for 15 minutes at a speed of 400 r / min to obtain the γ-aminopropyltriethoxysilane hydrolysate.

[0063] The iron oxide suspension was prepared by the following method: nano-iron oxide was dispersed in anhydrous ethanol at a mass ratio of 1:5, stirring was started and stirred for 30 minutes at a speed of 600 r / min to obtain the iron oxide suspension.

[0064] The reflux reaction is carried out at a temperature of 70°C.

[0065] The washing process involves rinsing the solid with anhydrous ethanol.

[0066] The drying process involves controlling the drying temperature at 70℃ and drying for 12 hours.

[0067] Step 3: Prepare component A Polyurethane oligomers containing double bonds, glycerol, and diisodecyl phthalate were vacuum dried, and then magnetic filler, fumed silica, and p-toluenesulfonyl isocyanate were added in sequence. The mixture was stirred and dispersed for 45 minutes, and then degassed under vacuum to obtain component A.

[0068] The vacuum drying process involves controlling the vacuum level to ≤-0.095MPa and the temperature to 110℃ for 2 hours to remove water.

[0069] The stirring and dispersion process involves a stirring speed of 300 r / min.

[0070] The vacuum degassing process involves controlling the vacuum level to ≤-0.095MPa to remove gas.

[0071] The vacuum degassing time is 25 minutes.

[0072] Step 4: Preparation of composite catalyst Dimethyl carbonate was added dropwise to a triethylenediamine solution, and the reaction was carried out at a temperature of 6 h to obtain a delayed-type amine catalyst. The delayed-type amine catalyst was then mixed with dibutyltin dilaurate at a mass ratio of 3:1 to obtain a composite catalyst.

[0073] The triethylenediamine solution was obtained by mixing triethylenediamine and anhydrous ethanol at a mass ratio of 8:26.

[0074] The heating reaction is controlled at a temperature of 50°C.

[0075] The molar ratio of triethylenediamine to dimethyl carbonate is 1:1.

[0076] Step 5: Prepare component B MDI-type isocyanate prepolymer was mixed evenly with diisodecyl phthalate, a composite catalyst and heavy calcium carbonate were added, the mixture was heated and stirred for 1 hour, and then discharged under vacuum to obtain component B.

[0077] The MDI-type isocyanate prepolymer is BASF Lupranate 5025, with an NCO content of 12.9%.

[0078] The heating and stirring process involves controlling the rotation speed at 600 r / min and the stirring temperature at 50°C.

[0079] The vacuum degassing process involves controlling the vacuum level to ≤-0.095MPa to remove gas.

[0080] The vacuum degassing time is 30 minutes.

[0081] Application method of sealant: Mix components A and B in a mass ratio of 1.3:1 to form the sealant. After applying the sealant to the bonding of new energy vehicle components, place the bonded parts in an alternating magnetic field with a frequency of 50kHz and a magnetic field strength of 5kA / m for 5 minutes.

[0082] Example 2: A high-curing-rate sealant for new energy vehicles includes component A and component B; the mass ratio of component A to component B is 1.4:1.

[0083] The raw material weight ratio of component A is as follows: 30 parts of polyurethane oligomer containing double bonds, 3.5 parts of glycerol, 25 parts of magnetic filler, 15 parts of diisodecyl phthalate, 3.5 parts of fumed silica, and 1 part of p-toluenesulfonyl isocyanate. All the above parts are by weight.

[0084] The raw materials for the polyurethane oligomer containing double bonds include polytetrahydrofuran ether diol, isophorone diisocyanate, hydroxyethyl methacrylate, hydroquinone, and dibutyltin dilaurate.

[0085] The magnetic filler is surface-modified nano-ferric oxide, and the modifier used is γ-aminopropyltriethoxysilane.

[0086] The raw material weight ratio of component B is as follows: 50 parts of MDI type isocyanate prepolymer, 2 parts of composite catalyst, 32 parts of heavy calcium carbonate, and 10 parts of diisodecyl phthalate. All the above parts are by weight.

[0087] The composite catalyst is obtained by mixing a delayed amine catalyst with dibutyltin dilaurate at a mass ratio of 4:1.

[0088] A method for preparing a high-curing-rate sealant for new energy vehicles includes the following steps: Step 1: Preparation of polyurethane oligomers containing double bonds Dehydrated polytetrahydrofuran ether diol was mixed with isophorone diisocyanate, and dibutyltin dilaurate was added dropwise. The mixture was stirred for 3 hours to obtain an NCO-terminated polyurethane prepolymer. Hydroxyethyl methacrylate and hydroquinone were added dropwise to the reaction system, and the mixture was stirred for another 5 hours. After volatilization at elevated temperature, a polyurethane oligomer containing double bonds was obtained.

[0089] The dehydration process involves adding polytetrahydrofuran ether diol to a reactor, controlling the reactor temperature at 100°C, and drying for 2.5 hours under a vacuum of ≤-0.095MPa. The reactor is then cooled to 80°C.

[0090] The molecular weight of the polytetrahydrofuran ether diol is 3000 Da.

[0091] The stirring reaction was carried out at a temperature of 80°C and a stirring rate of 100 r / min.

[0092] The temperature-induced devolatilization process involves controlling the vacuum level to ≤-0.09MPa and the temperature to 80℃ to remove residual monomers.

[0093] The molar ratio of polytetrahydrofuran ether diol, isophorone diisocyanate, hydroxyethyl methacrylate, hydroquinone, and dibutyltin dilaurate is 1:1.55:1.1:0.005:0.0008.

[0094] Step 2: Preparation of magnetically inductive filler The hydrolysate of γ-aminopropyltriethoxysilane was added dropwise to a suspension of iron oxide, and the mixture was refluxed for 5 hours. The solid was collected by filtration, washed, dried, and ground to obtain a magnetic filler.

[0095] The mass ratio of the γ-aminopropyltriethoxysilane hydrolysate to the iron tetroxide suspension is 1:10.

[0096] The γ-aminopropyltriethoxysilane hydrolysate was prepared by the following method: γ-aminopropyltriethoxysilane was mixed with a 55% ethanol solution at a mass ratio of 1:5; the mixed γ-aminopropyltriethoxysilane and ethanol solution were stirred for 25 minutes at a speed of 300 r / min to obtain the γ-aminopropyltriethoxysilane hydrolysate.

[0097] The iron oxide suspension was prepared by the following method: nano-iron oxide was dispersed in anhydrous ethanol at a mass ratio of 1:7, stirring was started and stirred for 45 minutes at a speed of 450 r / min to obtain the iron oxide suspension.

[0098] The reflux reaction is carried out at a temperature of 75°C.

[0099] The washing process involves rinsing the solid with anhydrous ethanol.

[0100] The drying process involves controlling the drying temperature at 75℃ and drying for 10 hours.

[0101] Step 3: Prepare component A Polyurethane oligomers containing double bonds, glycerol, and diisodecyl phthalate were vacuum dried, and then magnetic filler, fumed silica, and p-toluenesulfonyl isocyanate were added in sequence. The mixture was stirred and dispersed for 60 minutes, and then degassed under vacuum to obtain component A.

[0102] The vacuum drying process involves controlling the vacuum level to ≤-0.095MPa and the temperature to 120℃ for 1 hour of dehydration.

[0103] The stirring and dispersion process involves a stirring speed of 600 r / min.

[0104] The vacuum degassing process involves controlling the vacuum level to ≤-0.095MPa to remove gas.

[0105] The vacuum degassing time is 45 minutes.

[0106] Step 4: Preparation of composite catalyst Dimethyl carbonate was added dropwise to a triethylenediamine solution, and the reaction was carried out at a temperature of 4 h to obtain a delayed-type amine catalyst. The delayed-type amine catalyst was then mixed with dibutyltin dilaurate at a mass ratio of 4:1 to obtain a composite catalyst.

[0107] The triethylenediamine solution was obtained by mixing triethylenediamine and anhydrous ethanol at a mass ratio of 8:23.

[0108] The heating reaction: the reaction temperature is controlled at 55℃.

[0109] The molar ratio of triethylenediamine to dimethyl carbonate is 1:1.05.

[0110] Step 5: Prepare component B MDI-type isocyanate prepolymer was mixed evenly with diisodecyl phthalate, a composite catalyst and heavy calcium carbonate were added, the mixture was heated and stirred for 1 hour, and then discharged under vacuum to obtain component B.

[0111] The MDI-type isocyanate prepolymer is BASF Lupranate 5070 with an NCO content of 13%.

[0112] The heating and stirring process involves controlling the rotation speed at 800 r / min and the stirring temperature at 50°C.

[0113] The vacuum degassing process involves controlling the vacuum level to ≤-0.095MPa to remove gas.

[0114] The vacuum degassing time is 25 minutes.

[0115] Application method of sealant: Mix components A and B at a mass ratio of 1.4:1 to form the sealant. After applying the sealant to the bonding of new energy vehicle components, place the bonded parts in an alternating magnetic field with a frequency of 75kHz and a magnetic field strength of 10kA / m for 3 minutes.

[0116] Example 3: A high-curing-rate sealant for new energy vehicles includes component A and component B; the mass ratio of component A to component B is 1.5:1.

[0117] The raw material proportions of component A are as follows: 35 parts of polyurethane oligomer containing double bonds, 5 parts of glycerol, 34 parts of magnetic filler, 20 parts of diisodecyl phthalate, 5 parts of fumed silica, and 2 parts of p-toluenesulfonyl isocyanate. All of the above proportions are by weight.

[0118] The raw materials for the polyurethane oligomer containing double bonds include polytetrahydrofuran ether diol, isophorone diisocyanate, hydroxyethyl methacrylate, hydroquinone, and dibutyltin dilaurate.

[0119] The magnetic filler is surface-modified nano-ferric oxide, and the modifier used is γ-aminopropyltriethoxysilane.

[0120] The raw material weight ratio of component B is as follows: 60 parts of MDI type isocyanate prepolymer, 3 parts of composite catalyst, 40 parts of heavy calcium carbonate, and 15 parts of diisodecyl phthalate. All the above parts are by weight.

[0121] The composite catalyst is obtained by mixing a delayed-type amine catalyst with dibutyltin dilaurate at a mass ratio of 3:1. A method for preparing a high-curing-rate sealant for new energy vehicles includes the following steps: Step 1: Preparation of polyurethane oligomers containing double bonds Dehydrated polytetrahydrofuran ether diol was mixed with isophorone diisocyanate, and dibutyltin dilaurate was added dropwise. The mixture was stirred for 4 hours to obtain an NCO-terminated polyurethane prepolymer. Hydroxyethyl methacrylate and hydroquinone were added dropwise to the reaction system, and the mixture was stirred for another 3 hours. After volatilization at elevated temperature, a polyurethane oligomer containing double bonds was obtained.

[0122] The dehydration process involves adding polytetrahydrofuran ether diol to a reactor, controlling the reactor temperature at 120°C, and drying for 1.5 hours under a vacuum of ≤-0.095MPa. The reactor is then cooled to 85°C.

[0123] The molecular weight of the polytetrahydrofuran ether diol is 1000 Da.

[0124] The stirring reaction was carried out at a temperature of 85°C and a stirring rate of 50 r / min.

[0125] The heating and devolatilization process involves controlling the vacuum level to ≤-0.09MPa and the temperature to 85℃ to remove residual monomers.

[0126] The molar ratio of polytetrahydrofuran ether diol, isophorone diisocyanate, hydroxyethyl methacrylate, hydroquinone, and dibutyltin dilaurate is 1:1.6:1.2:0.01:0.001.

[0127] Step 2: Preparation of magnetically inductive filler The hydrolysate of γ-aminopropyltriethoxysilane was added dropwise to a suspension of iron oxide, and the mixture was refluxed for 4 hours. The solid was collected by filtration, washed, dried, and ground to obtain a magnetic filler.

[0128] The mass ratio of the γ-aminopropyltriethoxysilane hydrolysate to the iron tetroxide suspension is 1:15.

[0129] The γ-aminopropyltriethoxysilane hydrolysate was prepared by the following method: γ-aminopropyltriethoxysilane was mixed with a 50% ethanol solution at a mass ratio of 1:6; the mixed γ-aminopropyltriethoxysilane and ethanol solution were stirred for 30 minutes at a speed of 200 r / min to obtain the γ-aminopropyltriethoxysilane hydrolysate.

[0130] The iron oxide suspension was prepared by the following method: nano-iron oxide was dispersed in anhydrous ethanol at a mass ratio of 1:7, stirring was started and stirred for 60 minutes at a speed of 300 r / min to obtain the iron oxide suspension.

[0131] The reflux reaction is carried out at a temperature of 80°C.

[0132] The washing process involves rinsing the solid with anhydrous ethanol.

[0133] The drying process involves controlling the drying temperature at 80℃ and drying for 8 hours.

[0134] Step 3: Prepare component A Polyurethane oligomers containing double bonds, glycerol, and diisodecyl phthalate were vacuum dried, and then magnetic filler, fumed silica, and p-toluenesulfonyl isocyanate were added in sequence. The mixture was stirred and dispersed for 45 minutes, and then degassed under vacuum to obtain component A.

[0135] The vacuum drying process involves controlling the vacuum level to ≤-0.095MPa and the temperature to 120℃ for 2 hours to remove water.

[0136] The stirring and dispersion process involves a stirring speed of 600 r / min.

[0137] The vacuum degassing process involves controlling the vacuum level to ≤-0.095MPa to remove gas.

[0138] The vacuum degassing time is 25 minutes.

[0139] Step 4: Preparation of composite catalyst Dimethyl carbonate was added dropwise to a triethylenediamine solution, and the reaction was carried out at a temperature of 6 h to obtain a delayed-type amine catalyst. The delayed-type amine catalyst was then mixed with dibutyltin dilaurate at a mass ratio of 3:1 to obtain a composite catalyst.

[0140] The triethylenediamine solution was obtained by mixing triethylenediamine and anhydrous ethanol at a mass ratio of 8:24.

[0141] The heating reaction: the reaction temperature is controlled at 60℃.

[0142] The molar ratio of triethylenediamine to dimethyl carbonate is 1:1.

[0143] Step 5: Prepare component B MDI-type isocyanate prepolymer was mixed evenly with diisodecyl phthalate, a composite catalyst and heavy calcium carbonate were added, the mixture was heated and stirred for 1.5 h, and after vacuum degassing, the product was discharged to obtain component B.

[0144] The MDI-type isocyanate prepolymer is BASF Lupranate 5600 with an NCO content of 15%.

[0145] The heating and stirring process involves controlling the rotation speed at 800 r / min and the stirring temperature at 40°C.

[0146] The vacuum degassing process involves controlling the vacuum level to ≤-0.095MPa to remove gas.

[0147] The vacuum degassing time is 45 minutes.

[0148] Application method of sealant: Mix components A and B at a mass ratio of 1.5:1 to form the sealant. After applying the sealant to the bonding of new energy vehicle components, place the bonded parts in an alternating magnetic field with a frequency of 100kHz and a magnetic field strength of 15kA / m for 2 minutes.

[0149] Comparative Example 1 Based on Example 1, the composite catalyst of component B in the formulation was replaced with an equal amount of dibutyltin dilaurate, and other operations were the same as in Example 1. The specific operations are as follows: Steps 1, 2, and 3 are the same as steps 1, 2, and 3 in Example 1.

[0150] Dibutyltin dilaurate is used as a catalyst in step 4.

[0151] Step 5 is the same as step 5 in Example 1.

[0152] Comparative Example 2 Based on Example 1, the magnetic filler in component A of the formulation is replaced with an equal amount of light calcium carbonate, and other operations are the same as in Example 1. The specific operations are as follows: Step 1 is the same as step 1 in Example 1.

[0153] Light calcium carbonate is used as a filler in step 2.

[0154] Steps 3, 4, and 5 are the same as steps 3, 4, and 5 in Example 1.

[0155] Performance testing The sealants of Examples 1, 2, and 3 and Comparative Examples 1 and 2 were subjected to performance tests. The test indicators and test methods are as follows, and the test results are shown in Table 1.

[0156] 1. Workability: Tested according to the method in GB / T 7123.1-2015 "Determination of workability of multi-component adhesives".

[0157] 2. Curing rate: Tested according to the method in HG / T 4363-2012 "Single-component polyurethane sealant for automotive window glass".

[0158] 3. Tensile strength and elongation at break: The tensile strength and elongation at break shall be tested according to the method in HG / T 4363-2012 "Single-component polyurethane sealant for automotive window glass".

[0159] 4. Adhesion performance: The tensile shear strength is tested according to the method in GB / T 7124-2008 "Determination of tensile shear strength of adhesives (rigid material to rigid material)".

[0160] 5. Moisture and heat resistance: Prepare corresponding test pieces according to the method in HG / T 4363-2012 "Single-component polyurethane sealant for automotive window glass" and conduct moisture and heat resistance test treatment: place the test pieces at 70℃ and 95% relative humidity for 300h, and then place them under standard conditions for 4h. Take out the test pieces and test the tensile shear strength. The corresponding value is N2. The change rate of moisture and heat resistance R = (N2-N1) / N1×100%, where N1 is the performance test value corresponding to 168h under standard conditions, and N2 is the performance test value corresponding to the moisture and heat resistance test.

[0161] Table 1 Performance Test Results As shown in Table 1, the workable time of the sealant of this invention is 34-40 minutes, which is significantly longer than that of Comparative Example 1; the curing rate is 21-25 mm / 24h, which is a significant improvement compared to Comparative Example 2. The tensile strength of the sealant of this invention is 6.6 MPa-7.1 MPa, and the elongation at break is 462%-475%, demonstrating the excellent strength and toughness of the product. The tensile shear strength of the sealant of this invention is 3.6 MPa-3.9 MPa, and after 300 hours of damp heat testing, the change rate of tensile shear strength in damp heat resistance is only -4.2% to -4.8%, indicating a small performance degradation and stable performance with excellent adhesion and damp heat resistance.

[0162] Obviously, there are many other specific implementation methods that can be varied under the concept of this invention. It should be stated here that any changes made under the inventive concept of this invention will fall within the protection scope of this invention.

Claims

1. A high-curing-rate sealant for new energy vehicles, comprising component A and component B, characterized in that: The raw materials for component A, by weight, include: 25-35 parts of polyurethane oligomer containing double bonds, 2-5 parts of glycerol, 22-34 parts of magnetic filler, 10-20 parts of diisodecyl phthalate, 2-5 parts of fumed silica, and 0.5-2 parts of p-toluenesulfonyl isocyanate. The raw materials for preparing component B, by weight, include: 40-60 parts of MDI-type isocyanate prepolymer, 1-3 parts of composite catalyst, 25-40 parts of heavy calcium carbonate, and 5-15 parts of diisodecyl phthalate. The polyurethane oligomer containing double bonds is prepared from the following raw materials: polytetrahydrofuran ether diol, isophorone diisocyanate, hydroxyethyl methacrylate, hydroquinone, and dibutyltin dilaurate, wherein the molar ratio of the raw materials is 1:(1.5-1.6):(1.0-1.2):(0.005-0.01):(0.0005-0.001). The magnetic filler is surface-modified nano-Fe3O4, and the modifier used is γ-aminopropyltriethoxysilane. The MDI-type isocyanate prepolymer has an NCO content of 13%-15%. The composite catalyst is obtained by mixing a delayed amine catalyst with dibutyltin dilaurate at a mass ratio of (2-4):1; the delayed amine catalyst is prepared by reacting triethylenediamine with dimethyl carbonate at a molar ratio of 1:(1-1.05).

2. The high-curing-rate sealant for new energy vehicles according to claim 1, characterized in that: The nano-iron oxide has a particle size of 30-40 nm and a purity >99.5%; the polytetrahydrofuran ether diol has a molecular weight of 1000-3000 Da.

3. A method for preparing a high-curing-rate sealant for new energy vehicles, characterized in that: Includes the following steps: Step 1: Mix polytetrahydrofuran ether diol and isophorone diisocyanate, add dibutyltin dilaurate dropwise, stir and react for 2-4 hours to obtain NCO-terminated polyurethane prepolymer; add hydroxyethyl methacrylate and hydroquinone dropwise to the reaction system, continue stirring and react for 3-6 hours, and obtain polyurethane oligomer containing double bonds after temperature rise and devolatilization. Step 2: Add the γ-aminopropyltriethoxysilane hydrolysate dropwise to the iron oxide suspension, reflux for 4-6 hours, filter and collect the solid, wash the solid, dry and grind it to obtain the magnetic filler; the mass ratio of the γ-aminopropyltriethoxysilane hydrolysate to the iron oxide suspension is 1:(10-15). Step 3: After vacuum drying the polyurethane oligomer containing double bonds, glycerol, and diisodecyl phthalate, add the magnetic filler, fumed silica, and p-toluenesulfonyl isocyanate in sequence, stir to remove bubbles, and obtain component A. Step 4: Add dimethyl carbonate dropwise to triethylenediamine solution and heat for 4-6 hours to obtain a delayed amine catalyst; mix the delayed amine catalyst with dibutyltin dilaurate at a mass ratio of (2-4):1 to obtain a composite catalyst; Step 5: Mix the MDI-type isocyanate prepolymer with diisodecyl phthalate, add the composite catalyst and heavy calcium carbonate, heat and stir for 1-1.5 hours, and degas under vacuum to obtain component B.

4. The method for preparing a high-curing-rate sealant for new energy vehicles according to claim 3, characterized in that: The stirring reaction described in step 1: the reaction temperature is 75-85℃, and the stirring rate is 50-150r / min; the heating and devolatilization: the vacuum degree is controlled to be ≤-0.09MPa and the temperature is 75-85℃.

5. The method for preparing a high-curing-rate sealant for new energy vehicles according to claim 3, characterized in that: The γ-aminopropyltriethoxysilane hydrolysate described in step 2 comprises the following raw materials: γ-aminopropyltriethoxysilane and ethanol solution; the ethanol solution has a mass fraction of 45-55%; and the mass ratio of γ-aminopropyltriethoxysilane to ethanol solution is 1:(5-6).

6. The method for preparing a high-curing-rate sealant for new energy vehicles according to claim 3, characterized in that: The iron oxide suspension described in step 2 comprises the following raw materials: nano iron oxide and anhydrous ethanol; the mass ratio of nano iron oxide to anhydrous ethanol is 1:(5-7); the reflux reaction is carried out at a temperature of 70-80℃.

7. The method for preparing a high-curing-rate sealant for new energy vehicles according to claim 3, characterized in that: The vacuum drying in step 3 involves controlling the vacuum degree to ≤-0.095MPa and the temperature to 110-120℃ for 1-2 hours; the stirring and degassing involves controlling the stirring speed to 300-600r / min, controlling the vacuum degree to ≤-0.095MPa, and the stirring and degassing time to 25-45 minutes.

8. The method for preparing a high-curing-rate sealant for new energy vehicles according to claim 3, characterized in that: In step 4, the triethylenediamine solution is prepared by a mass ratio of triethylenediamine to anhydrous ethanol of 8:(23-26); the heating reaction is carried out at a temperature of 50-60℃.

9. The method for preparing a high-curing-rate sealant for new energy vehicles according to claim 3, characterized in that: In step 4, the molar ratio of triethylenediamine to dimethyl carbonate is 1:(1-1.05).

10. The method for preparing a high-curing-rate sealant for new energy vehicles according to claim 3, characterized in that: Step 5 involves heating and stirring: controlling the stirring temperature at 40-50℃ and the stirring speed at 600-800 r / min; and vacuum degassing: the vacuum degree is ≤-0.095MPa, and the degassing time is 25-45 minutes.

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