阅读说明：本技术 一种动力电池托盘用多功能聚脲涂层及其制备方法和应用 (Multifunctional polyurea coating for power battery tray and preparation method and application thereof ) 是由 王楠 陈阳 唐玲玲 傅嘉琳 韩贞毅 于 2021-08-20 设计创作，主要内容包括：本发明属于纯电动汽车涂层技术领域,提供了一种动力电池托盘用多功能聚脲涂层及其制备方法和应用,通过改性异氰酸酯提高了聚脲涂层对基体的附着力,从而提高了涂层的抗冲击性能；通过添加改性碳纳米纤维、改性纳米三氟化铈和改性纳米三氟化镧,提高了聚脲涂层的抗冲击性能,同时使得涂层具有超疏水性；通过添加石墨烯,进一步提高了涂层的抗冲击性能；通过添加阻燃剂,使得涂层具有稳定高效的阻燃性能。实施例的结果显示,本发明提供的动力电池托盘用多功能聚脲涂层的拉伸强度为40MPa,断裂伸长率为450％,撕裂强度为121kN/m,接触角为153°,UL-94阻燃测试为V0,与45钢的附着力为16.57MPa。(The invention belongs to the technical field of pure electric vehicle coatings, and provides a multifunctional polyurea coating for a power battery tray, a preparation method and application thereof, wherein the adhesive force of the polyurea coating to a matrix is improved through modified isocyanate, so that the impact resistance of the coating is improved; by adding the modified carbon nanofiber, the modified nano cerium trifluoride and the modified nano lanthanum trifluoride, the shock resistance of the polyurea coating is improved, and the coating has super-hydrophobicity; by adding the graphene, the impact resistance of the coating is further improved; by adding the flame retardant, the coating has stable and efficient flame retardant performance. The results of the examples show that the multifunctional polyurea coating for the power battery tray provided by the invention has the tensile strength of 40MPa, the elongation at break of 450%, the tear strength of 121kN/m, the contact angle of 153 degrees, the UL-94 flame retardant test of V0 and the adhesion force with 45 steel of 16.57 MPa.)

1. A multifunctional polyurea coating for a power battery tray is formed by curing a component A and a component B; the mass ratio of the component A to the component B is 1: 1.3-1.5;

the raw materials for preparing the component A comprise the following components in parts by weight: 30-55 parts of modified isocyanate, 20-40 parts of polyether polyol, 1-10 parts of diluent, 1-10 parts of flame retardant and 2-10 parts of modified carbon nanofiber;

the modified isocyanate is carbon nanofiber CNF-OH modified isocyanate with hydroxyl on the surface;

the preparation method of the modified carbon nanofiber comprises the following steps: modifying carbon nanofiber CNF-OH with hydroxyl on the surface by using methyltrimethoxysilane to obtain modified carbon nanofiber;

the raw materials for preparing the component B comprise the following components in parts by weight: 10-28 parts of chain extender, 30-55 parts of amino-terminated polyether, 5-15 parts of diluent, 1-5 parts of graphene, 1-10 parts of foaming agent, 4-6 parts of modified nano cerium trifluoride, 3-5 parts of modified nano lanthanum trifluoride and 12-20 parts of assistant;

the preparation method of the modified nano cerium trifluoride comprises the following steps: mixing nano cerium trifluoride dissolved in magnesium silicate hydroxide with oleic acid and polydimethylsiloxane for modification to obtain modified nano cerium trifluoride;

the preparation method of the modified nano lanthanum trifluoride comprises the following steps: and performing hydrothermal modification treatment on the nano lanthanum trifluoride by using vinyl triethoxysilane and hexamethyldisilazane as modifiers to obtain the modified nano lanthanum trifluoride.

2. The multifunctional polyurea coating for power battery trays of claim 1, wherein the isocyanate in the modified isocyanate comprises one or more of toluene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, polymethylene polyphenyl polyisocyanate and isophorone diisocyanate.

3. The multi-functional polyurea coating for power battery trays of claim 1, wherein the polyether polyol comprises one or more of polyoxypropylene glycol, flame retardant polyether polyol, and polytetrahydrofuran glycol.

4. The multifunctional polyurea coating for power battery trays of claim 1, wherein the diluent in component a and component B independently comprises propylene carbonate or n-butyl acetate.

5. The multifunctional polyurea coating for power battery trays of claim 1, wherein the flame retardant comprises one or more of ammonium polyphosphate, melamine polyphosphate, tris (hydroxymethyl) phosphine oxide, phosphate, and hyperbranched phosphorous-containing polyurethane.

6. The multi-functional polyurea coating for power cell trays of claim 1, wherein the chain extender comprises one or more of diethyltoluenediamine, dimethylthiotoluenediamine, and N, N' -dialkylmethyl diamine.

7. The multifunctional polyurea coating for the power battery tray according to claim 1, wherein the auxiliary agent comprises, by weight, 7 to 10 parts of ethyl acetate, 2 to 3 parts of a leveling agent, 1 to 2 parts of an antifoaming agent, and 2 to 5 parts of a silane coupling agent.

8. The multifunctional polyurea coating for power battery trays of claim 1, wherein the blowing agent comprises azobisisobutyronitrile or N, N '-dimethyl-N, N' -dinitrosoterephthalamide.

9. The method for preparing the multifunctional polyurea coating for the power battery tray according to any one of claims 1 to 8, comprising: and mixing the component A and the component B at 50-70 ℃, and spraying to obtain the multifunctional polyurea coating for the power battery tray.

10. The multifunctional polyurea coating for the power battery tray as defined in any one of claims 1 to 8 or the multifunctional polyurea coating for the power battery tray prepared by the preparation method as defined in claim 9 is applied to the power battery tray.

Technical Field

The invention relates to the technical field of coatings of pure electric vehicles, in particular to a multifunctional polyurea coating for a power battery tray, and a preparation method and application thereof.

Background

The pure electric vehicle has a high vehicle type occupation ratio in new energy vehicles, and compared with the traditional vehicles, the pure electric vehicle is the most different in power source. The traditional automobile uses an engine using fuel oil as an energy source to do work to provide power, and the new energy automobile uses a power battery (the electric storage capacity is more than 75%) combined with a driving motor and a motor controller as a power source. The power battery is used as the core of the new energy automobile, and once electrolyte leakage or battery temperature runaway and other conditions occur, the whole automobile can be burnt or even explode. At present, most of electric automobiles are provided with a power battery pack on a tray in order to obtain enough space in the automobiles and improve the running performance of the whole automobiles, and the tray is arranged at the position of a chassis of the whole automobiles, so that the working condition of the chassis of the automobiles is very severe, the tray is extremely easy to corrode, stain, impact and the like, and the power battery pack is easy to lose control to bring dangers such as combustion and explosion of the electric automobiles, so that the power battery pack is of great importance to the protection of the power battery tray.

The polyurea is an elastomer spraying material formed by the reaction of an isocyanate component and an amino compound, has the advantages of environmental protection and low price, and has good impact strength, flexibility, water resistance, corrosion resistance and construction performance. However, when the polyurea coating material is used for a power battery tray, the polyurea coating material needs to face the very severe working conditions of an automobile chassis, such as high-speed impact of road stones, continuous erosion in rainy days and the like, and the polyurea coating material is required to be capable of preventing the spread of fire, and the existing polyurea coating material cannot maintain good waterproof and impact resistance under the working conditions and does not have flame retardant performance. Therefore, it is highly desirable to provide a polyurea coating with super-hydrophobic, high impact resistance and flame retardant properties to protect the power battery tray and prevent the occurrence of the risks of burning and explosion of the electric vehicle.

Disclosure of Invention

The invention aims to provide a multifunctional polyurea coating for a power battery tray, and a preparation method and application thereof.

The invention provides a multifunctional polyurea coating for a power battery tray, which is formed by curing a component A and a component B; the mass ratio of the component A to the component B is 1: 1.3-1.5;

the raw materials for preparing the component A comprise the following components in parts by weight: 30-55 parts of modified isocyanate, 20-40 parts of polyether polyol, 1-10 parts of diluent, 1-10 parts of flame retardant and 2-10 parts of modified carbon nanofiber;

the modified isocyanate is carbon nanofiber CNF-OH modified isocyanate with hydroxyl on the surface;

the preparation method of the modified carbon nanofiber comprises the following steps: modifying carbon nanofiber CNF-OH with hydroxyl on the surface by using methyltrimethoxysilane to obtain modified carbon nanofiber;

the raw materials for preparing the component B comprise the following components in parts by weight: 10-28 parts of chain extender, 30-55 parts of amino-terminated polyether, 5-15 parts of diluent, 1-5 parts of graphene, 1-10 parts of foaming agent, 4-6 parts of modified nano cerium trifluoride, 3-5 parts of modified nano lanthanum trifluoride and 12-20 parts of assistant;

the preparation method of the modified nano cerium trifluoride comprises the following steps: mixing nano cerium trifluoride dissolved in magnesium silicate hydroxide with oleic acid and polydimethylsiloxane for modification to obtain modified nano cerium trifluoride;

the preparation method of the modified nano lanthanum trifluoride comprises the following steps: and performing hydrothermal modification treatment on the nano lanthanum trifluoride by using vinyl triethoxysilane and hexamethyldisilazane as modifiers to obtain the modified nano lanthanum trifluoride.

Preferably, the isocyanate in the modified isocyanate includes one or more of toluene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, polymethylene polyphenyl polyisocyanate and isophorone diisocyanate.

Preferably, the polyether polyol comprises one or more of polyoxypropylene glycol, flame retardant polyether polyol and polytetrahydrofuran glycol.

Preferably, the diluents in component a and component B independently comprise propylene carbonate or n-butyl acetate.

Preferably, the flame retardant comprises one or more of ammonium polyphosphate, melamine polyphosphate, tris-hydroxy phosphine oxide, phosphate and hyperbranched phosphorus-containing polyurethane.

Preferably, the chain extender comprises one or more of diethyltoluenediamine, dimethylthiotoluenediamine and N, N' -dialkylmethyldiamine.

Preferably, the auxiliary agent comprises, by weight, 7-10 parts of ethyl acetate, 2-3 parts of a leveling agent, 1-2 parts of a defoaming agent and 2-5 parts of a silane coupling agent.

Preferably, the blowing agent comprises azobisisobutyronitrile or N, N '-dimethyl-N, N' -dinitrosoterephthalamide.

The invention also provides a preparation method of the multifunctional polyurea coating for the power battery tray, which comprises the following steps: and mixing the component A and the component B at 50-70 ℃, and spraying to obtain the multifunctional polyurea coating for the power battery tray.

The invention also provides the application of the multifunctional polyurea coating for the power battery tray or the multifunctional polyurea coating for the power battery tray prepared by the preparation method in the power battery tray.

The invention provides a multifunctional polyurea coating for a power battery tray, which is formed by curing a component A and a component B; the mass ratio of the component A to the component B is 1: 1.3-1.5; the raw materials for preparing the component A comprise the following components in parts by weight: 30-55 parts of modified isocyanate, 20-40 parts of polyether polyol, 1-10 parts of diluent, 1-10 parts of flame retardant and 2-10 parts of modified carbon nanofiber; the modified isocyanate is carbon nanofiber CNF-OH modified isocyanate with hydroxyl on the surface; the preparation method of the modified carbon nanofiber comprises the following steps: modifying carbon nanofiber CNF-OH with hydroxyl on the surface by using methyltrimethoxysilane to obtain modified carbon nanofiber; the component B is prepared from the following raw materials in parts by weight: 10-28 parts of chain extender, 30-55 parts of amino-terminated polyether, 5-15 parts of diluent, 1-5 parts of graphene, 1-10 parts of foaming agent, 4-6 parts of modified nano cerium trifluoride, 3-5 parts of modified nano lanthanum trifluoride and 12-20 parts of assistant; the preparation method of the modified nano cerium trifluoride comprises the following steps: mixing nano cerium trifluoride dissolved in magnesium silicate hydroxide with oleic acid and polydimethylsiloxane for modification to obtain modified nano cerium trifluoride; the preparation method of the modified nano lanthanum trifluoride comprises the following steps: and performing hydrothermal modification treatment on the nano lanthanum trifluoride by using vinyl triethoxysilane and hexamethyldisilazane as modifiers to obtain the modified nano lanthanum trifluoride. The adhesive force of the polyurea coating to the matrix is improved through the modified isocyanate, so that the impact resistance of the coating is improved; by adding the modified carbon nanofiber, the modified nano cerium trifluoride and the modified nano lanthanum trifluoride, the impact resistance of the polyurea coating is improved, the coating has super-hydrophobicity, the waterproof and anti-fouling performance of the coating is improved, and the bonding force and the wear resistance of the coating and the surface of a substrate can be improved by the modified cerium trifluoride, so that the coating can still keep extremely high tearing strength under high-speed impact; by adding the graphene, the impact resistance of the coating is further improved; by adding the flame retardant, the coating has stable and efficient flame retardant performance. The results of the examples show that the multifunctional polyurea coating for the power battery tray provided by the invention has the tensile strength of 40MPa, the elongation at break of 450%, the tear strength of 121kN/m, the contact angle of 153 degrees, the UL-94 flame retardant test of V0, the adhesion force with 45 steel of 16.57MPa and the salt spray resistance of 2000 h.

Drawings

FIG. 1 is a schematic surface contact angle of a polyurea coating prepared according to example 1 of the present invention;

FIG. 2 is a schematic surface contact angle of a polyurea coating prepared in example 2 of the present invention;

FIG. 3 is a schematic surface contact angle of a polyurea coating prepared according to example 3 of the present invention.

Detailed Description

The invention provides a multifunctional polyurea coating for a power battery tray, which is formed by curing a component A and a component B; the mass ratio of the component A to the component B is 1: 1.3-1.5;

the raw materials for preparing the component A comprise the following components in parts by weight: 30-55 parts of modified isocyanate, 20-40 parts of polyether polyol, 1-10 parts of diluent, 1-10 parts of flame retardant and 2-10 parts of modified carbon nanofiber;

the modified isocyanate is carbon nanofiber CNF-OH modified isocyanate with hydroxyl on the surface;

the preparation method of the modified carbon nanofiber comprises the following steps: modifying carbon nanofiber CNF-OH with hydroxyl on the surface by using methyltrimethoxysilane to obtain modified carbon nanofiber;

the raw materials for preparing the component B comprise the following components in parts by weight: 10-28 parts of chain extender, 30-55 parts of amino-terminated polyether, 5-15 parts of diluent, 1-5 parts of graphene, 1-10 parts of foaming agent, 4-6 parts of modified nano cerium trifluoride, 3-5 parts of modified nano lanthanum trifluoride and 12-20 parts of assistant;

the preparation method of the modified nano cerium trifluoride comprises the following steps: mixing nano cerium trifluoride dissolved in magnesium silicate hydroxide with oleic acid and polydimethylsiloxane for modification to obtain modified nano cerium trifluoride;

the preparation method of the modified nano lanthanum trifluoride comprises the following steps: and performing hydrothermal modification treatment on the nano lanthanum trifluoride by using vinyl triethoxysilane and hexamethyldisilazane as modifiers to obtain the modified nano lanthanum trifluoride.

In the invention, the polyurea coating is formed by curing the component A and the component B; the mass ratio of the component A to the component B is 1: 1.3-1.5, and preferably 1: 1.4-1.5. The invention controls the mass ratio of the component A to the component B in the range, which is beneficial to the curing of the component A and the component B, and further obtains the multifunctional polyurea coating.

The raw materials for preparing the component A comprise, by weight, 30-55 parts of modified isocyanate, preferably 38-50 parts, and more preferably 47-50 parts. In the invention, the modified isocyanate is carbon nanofiber CNF-OH modified isocyanate with hydroxyl on the surface. According to the invention, the carbon nanofiber with hydroxyl on the surface is used for modifying isocyanate, so that the adhesive force of the polyurea coating to a matrix is improved, and the impact resistance of the coating is further improved.

In the present invention, the isocyanate in the modified isocyanate preferably includes one or more of toluene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, polymethylene polyphenyl polyisocyanate and isophorone diisocyanate, and more preferably one or more of diphenylmethane diisocyanate, isophorone diisocyanate and hexamethylene diisocyanate. The source of the isocyanate is not particularly limited in the present invention, and a commercially available product known to those skilled in the art may be used.

In the present invention, the preparation method of the modified isocyanate preferably includes: and mixing the carbon nanofiber CNF-OH with hydroxyl on the surface with isocyanate in a nitrogen atmosphere for modification to obtain the modified isocyanate. In the invention, the mass ratio of the carbon nanofiber CNF-OH with hydroxyl on the surface to isocyanate is preferably (1-2): 200, more preferably 1: 200. In the present invention, the mixing is preferably stirring after the ultrasonic treatment. In the invention, the power of ultrasonic treatment is preferably 30-50 kHz, and more preferably 40-45 kHz; the time of ultrasonic treatment is preferably 30-60 min, and more preferably 35-45 min. In the invention, the stirring speed is preferably 1500-2000 r/min, more preferably 1800-2000 r/min; the stirring time is preferably 3-5 h, and more preferably 5 h.

In the present invention, the preparation method of the carbon nanofiber CNF-OH having hydroxyl groups on the surface preferably includes:

mixing carbon nanofibers with concentrated nitric acid, and sequentially performing first ultrasonic treatment and first heating reflux to obtain acidified carbon nanofibers CNF-COOH;

mixing the acidified carbon nanofiber CNF-COOH with thionyl chloride, and then sequentially carrying out second ultrasonic treatment and second heating reflux to obtain acylated carbon nanofiber CNF-COCl;

and mixing the acylated carbon nanofiber CNF-COCl with ethylene glycol, and then sequentially carrying out third ultrasonic treatment and hydroxylation reaction to obtain the carbon nanofiber CNF-OH with hydroxyl on the surface.

According to the invention, the carbon nanofibers are preferably mixed with concentrated nitric acid, and then sequentially subjected to first ultrasonic treatment and first heating reflux to obtain the acidified carbon nanofibers CNF-COOH.

In the invention, the diameter of the carbon nanofiber is preferably 120-130 nm; the length of the carbon nanofiber is preferably 10-20 μm. In the invention, the volume ratio of the mass of the carbon nano fiber to the concentrated nitric acid is preferably (5-6) g: (80-100) mL. In the invention, the mass concentration of the concentrated nitric acid is preferably 75-78%.

In the invention, the frequency of the first ultrasonic treatment is preferably 25-30 kHz; the time of the first ultrasonic treatment is preferably 10-20 min.

In the invention, the temperature of the first heating reflux is preferably 120-130 ℃; the first heating reflux time is preferably 2-3 h.

After the first heating reflux is finished, the invention preferably sequentially dilutes, filters, washes and dries the product of the first heating reflux to obtain the acidified carbon nanofiber CNF-COOH. The operation of diluting, filtering, washing and drying is not particularly limited in the present invention, and the technical scheme of diluting, filtering, washing and drying, which is well known to those skilled in the art, can be adopted. In the present invention, the diluent used for the dilution is preferably deionized water; the amount of the deionized water is preferably 1000 mL. In the invention, the filter membrane used for suction filtration is preferably a mixed fiber microporous filter membrane with the diameter of phi 0.22 mu m. In the present invention, the detergent used for the washing is preferably deionized water. In the invention, the drying temperature is preferably 80-90 ℃; the drying time is preferably 24-25 h; the drying mode is preferably vacuum drying.

After the acidified carbon nanofiber CNF-COOH is obtained, the acidified carbon nanofiber CNF-COOH is preferably mixed with thionyl chloride, and then the second ultrasonic treatment and the second heating reflux are sequentially carried out, so that the acylated carbon nanofiber CNF-COCl is obtained.

In the invention, the ratio of the mass of the acidified carbon nanofiber CNF-COOH to the volume of thionyl chloride is preferably (2-3) g: (80-90) mL. In the invention, the frequency of the second ultrasonic treatment is preferably 25-30 kHz; the time of the second ultrasonic treatment is preferably 10-20 min. In the invention, the temperature of the second heating reflux is preferably 75-85 ℃; the second heating reflux time is preferably 24-25 h.

After the second heating reflux is finished, the invention preferably performs reduced pressure distillation on the product of the second heating reflux to obtain the carbon acylate nanofiber CNF-COCl. The invention removes excessive thionyl chloride by reduced pressure distillation, which is beneficial to obtaining pure carbon acylate nano-fiber CNF-COCl. The operation of the reduced pressure distillation is not particularly limited in the present invention, and a technical scheme of reduced pressure distillation known to those skilled in the art may be adopted.

After the carbon nanofiber CNF-COCl is obtained, the carbon nanofiber CNF-COCl is preferably mixed with ethylene glycol, and then the third ultrasonic treatment and hydroxylation reaction are sequentially carried out to obtain the carbon nanofiber CNF-OH with hydroxyl on the surface.

In the invention, the volume ratio of the mass of the carbon acylate nanofibers CNF-COCl to the ethylene glycol is preferably (1.5-2) g: (80-90) mL.

In the invention, the frequency of the third ultrasonic treatment is preferably 25-30 kHz; the time of the third ultrasonic treatment is preferably 10-20 min. In the invention, the temperature of the hydroxylation reaction is preferably 120-130 ℃; the hydroxylation reaction time is preferably 48-50 h.

After the hydroxylation reaction is finished, the invention preferably sequentially dilutes, filters, washes and dries the product of the hydroxylation reaction to obtain the carbon nanofiber CNF-OH with hydroxyl on the surface. The operation of diluting, filtering, washing and drying is not particularly limited in the present invention, and the technical scheme of diluting, filtering, washing and drying, which is well known to those skilled in the art, can be adopted. In the present invention, the diluent used for the dilution is preferably deionized water; the amount of the deionized water is preferably 1000 mL. In the invention, the filter membrane used for suction filtration is preferably a mixed fiber microporous filter membrane with the diameter of phi 0.22 mu m. In the present invention, the detergent used for the washing is preferably deionized water. In the invention, the drying temperature is preferably 80-90 ℃; the drying time is preferably 24-25 h; the drying mode is preferably vacuum drying.

The raw materials for preparing the component A comprise 20-40 parts of polyether polyol, preferably 22-35 parts of polyether polyol, and more preferably 23-25 parts of polyether polyol, by weight of the modified isocyanate 30-55 parts. In the present invention, the polyether polyol preferably includes one or more of polyoxypropylene glycol, flame retardant polyether polyol and polytetrahydrofuran glycol, and more preferably polyoxypropylene glycol and/or flame retardant polyether polyol. The source of the polyether polyol in the present invention is not particularly limited, and commercially available products known to those skilled in the art may be used.

The raw materials for preparing the component A comprise 1-10 parts of diluent, preferably 5-10 parts of diluent, and more preferably 8-10 parts of diluent, based on 30-55 parts of modified isocyanate. In the present invention, the diluent is used to adjust the NCO value and viscosity of component A. In the present invention, the diluent preferably comprises propylene carbonate or n-butyl acetate, more preferably propylene carbonate. The source of the diluent in the present invention is not particularly limited, and commercially available products known to those skilled in the art may be used.

The raw materials for preparing the component A comprise 1-10 parts of flame retardant, preferably 5-10 parts of flame retardant, and more preferably 8-10 parts of flame retardant, based on 30-55 parts of modified isocyanate. According to the invention, the polyurea coating has stable and efficient flame retardant performance by adding the flame retardant.

In the present invention, the flame retardant preferably comprises one or more of ammonium polyphosphate, melamine polyphosphate, trimethylol phosphine oxide, phosphate and hyperbranched phosphorus-containing polyurethane, and more preferably one or more of ammonium polyphosphate, melamine polyphosphate, trimethylol phosphine oxide and hyperbranched phosphorus-containing polyurethane. The source of the flame retardant is not particularly limited in the present invention, and commercially available products known to those skilled in the art may be used.

The raw materials for preparing the component A comprise 2-10 parts of modified carbon nanofibers, preferably 5-10 parts of modified carbon nanofibers, and more preferably 7-10 parts of modified isocyanate, by weight of 30-55 parts of modified isocyanate. According to the invention, the impact resistance and hydrophobicity of the polyurea coating are improved by adding the modified carbon nanofiber.

In the invention, the preparation method of the modified carbon nanofiber comprises the following steps: and modifying the carbon nanofiber CNF-OH with hydroxyl on the surface by using methyltrimethoxysilane to obtain the modified carbon nanofiber. In the present invention, the mass ratio of the volume of the methyltrimethoxysilane to the carbon nanofibers with hydroxyl groups on the surface is preferably 1 mL: 3g of the total weight. In the invention, the temperature of modification is preferably 20-30 ℃; the modification time is preferably 10-20 min; the modified device is preferably a closed reaction vessel.

After the modification is finished, the modified product is preferably dried to obtain the modified carbon nanofiber. In the invention, the drying temperature is preferably 110-150 ℃; the drying time is preferably 5-8 h; the drying means is preferably a dryer.

In the present invention, the preparation method of the component a preferably includes: reacting modified isocyanate with polyether polyol for 3-4 hours at 60-90 ℃ in a nitrogen atmosphere, sequentially adding a flame retardant, modified carbon nanofibers and a diluent, and stirring for 4-5 hours to obtain a component A.

The modified isocyanate and the polyether polyol are preferably reacted for 3-4 hours at 60-90 ℃ in a nitrogen atmosphere to obtain the polymer. The invention takes modified isocyanate and polyether glycol as raw materials to carry out polymerization reaction to prepare the polymer. In the invention, the reaction temperature is preferably 60-70 ℃; the reaction time is preferably 3 h.

After the polymer is obtained, the flame retardant, the modified carbon nanofiber and the diluent are preferably added in sequence, and stirred for 4-5 hours to obtain the component A. The flame retardant and the modified carbon nanofiber are added into the polymer to improve the flame retardant property and the hydrophobicity of the polymer, and the NCO value and the viscosity of the polymer are adjusted by adding the diluent. In the invention, the NCO value of the component A is preferably 12-15%; the viscosity of the component A is preferably 700-800 mPas. In the invention, the stirring speed is preferably 1800-2000 r/min; the stirring time is preferably 4 h.

The raw materials for preparing the component B comprise, by weight, 10-28 parts of a chain extender, preferably 20-28 parts, and more preferably 25-28 parts. In the present invention, the chain extender preferably includes one or more of diethyltoluenediamine, dimethylthiotoluenediamine, and N, N '-dialkylmethyldiamine, more preferably diethyltoluenediamine and N, N' -dialkylmethyldiamine. The source of the chain extender is not particularly limited in the present invention, and commercially available products known to those skilled in the art may be used.

The raw materials for preparing the component B comprise 30-55 parts of amino-terminated polyether, preferably 38-50 parts of amino-terminated polyether, and more preferably 44-50 parts of amino-terminated polyether, by weight of the chain extender being 10-28 parts. In the present invention, the amino-terminated polyether preferably comprises amino-terminated polyether T2000 or amino-terminated polyether D5000. The source of the amino-terminated polyether is not particularly limited in the present invention, and commercially available products known to those skilled in the art may be used.

The raw materials for preparing the component B comprise 5-15 parts of diluent, preferably 7-10 parts of diluent, and more preferably 9-10 parts of diluent, by weight of the chain extender being 10-28 parts. In the present invention, the diluent preferably comprises propylene carbonate or n-butyl acetate, more preferably n-butyl acetate. The source of the diluent in the present invention is not particularly limited, and commercially available products known to those skilled in the art may be used.

The raw materials for preparing the component B comprise 1-5 parts of graphene, preferably 1-2 parts, by weight of the chain extender of 10-28 parts. According to the invention, the impact resistance of the coating is further improved by adding the graphene. The source of the graphene is not particularly limited in the present invention, and commercially available products known to those skilled in the art may be used. In the present invention, the form of the graphene is preferably a powder.

The raw materials for preparing the component B comprise 1-10 parts of foaming agent, preferably 1-5 parts, and more preferably 1-3 parts by weight of chain extender of 10-28 parts. According to the invention, by adding the foaming agent, the use of the polyurea coating can be reduced, and the purposes of light weight of the whole vehicle, cost saving and noise reduction are achieved, and the impact resistance of the polyurea coating is not influenced.

In the present invention, the blowing agent preferably includes azobisisobutyronitrile or N, N '-dimethyl-N, N' -dinitrosoterephthalamide, more preferably azobisisobutyronitrile. The source of the blowing agent is not particularly limited in the present invention, and commercially available products known to those skilled in the art may be used.

The raw materials for preparing the component B comprise 4-6 parts of modified nano cerium trifluoride, preferably 5-6 parts by weight of chain extender. The modified cerium trifluoride is added, so that the hydrophobicity of the coating is improved, the binding force between the coating and the surface of the substrate and the wear resistance of the coating can be improved, and the coating can still keep extremely high tearing strength under high-speed impact.

In the invention, the preparation method of the modified nano cerium trifluoride comprises the following steps: mixing the nano cerium trifluoride dissolved in the magnesium silicate hydroxide with oleic acid and polydimethylsiloxane for modification to obtain the modified nano cerium trifluoride. In the present invention, the ratio of the mass of the nano cerium trifluoride to the volume of the magnesium silicate hydroxide is preferably (15 to 20) g: (25-30) mL; the temperature of the magnesium silicate hydroxide is preferably 80-85 ℃. In the invention, the mass ratio of the nano cerium trifluoride, the oleic acid and the polydimethylsiloxane is preferably (15-20): (4-5): (2-3). In the invention, the modification time is preferably 1-2 h. After the modification is completed, the modified product is preferably dried to obtain the modified cerium trifluoride. In the invention, the drying temperature is preferably 120-130 ℃; the drying time is preferably 4-6 h.

The raw materials for preparing the component B comprise 3-5 parts of modified nano lanthanum trifluoride, preferably 4-5 parts by weight of chain extender of 10-28 parts. The modified nanometer lanthanum trifluoride is added, so that the hydrophobicity and the impact resistance of the polyurea coating are improved.

In the invention, the preparation method of the modified nanometer lanthanum trifluoride comprises the following steps: and performing hydrothermal modification treatment on the nano lanthanum trifluoride by using vinyl triethoxysilane and hexamethyldisilazane as modifiers to obtain the modified nano lanthanum trifluoride. According to the invention, the nano lanthanum trifluoride is modified by using the vinyltriethoxysilane and the hexamethyldisilazane, so that the super-hydrophobicity of the nano lanthanum trifluoride is improved, and the super-hydrophobic polyurea coating is favorably obtained.

In the invention, the preparation method of the modified nano lanthanum trifluoride is preferably as follows: providing a nanometer lanthanum trifluoride suspension, adding vinyltriethoxysilane and hexamethyldisilazane into the nanometer lanthanum trifluoride suspension, and carrying out hydrothermal modification treatment to obtain the modified nanometer lanthanum trifluoride.

In the present invention, the preparation of the nano lanthanum trifluoride suspension preferably comprises: mixing the nanometer lanthanum trifluoride with absolute ethyl alcohol, and adjusting the pH value to obtain the nanometer lanthanum trifluoride suspension. In the present invention, the volume ratio of the mass of the nano lanthanum trifluoride to the absolute ethyl alcohol is preferably 15 g: 100 mL. In the invention, the mixing of the nano lanthanum trifluoride and the absolute ethyl alcohol is preferably carried out under the condition of stirring; the stirring speed is preferably 1000-1500 r/min; the stirring time is preferably 1 h; the stirring device is preferably a magnetic stirrer. In the invention, the pH value is preferably adjusted to be neutral, and the reagent used for adjusting the pH value is preferably ammonia water.

After the nanometer lanthanum trifluoride suspension is obtained, the invention preferably adds vinyl triethoxysilane and hexamethyldisilazane into the nanometer lanthanum trifluoride suspension for hydrothermal modification treatment to obtain the modified nanometer lanthanum trifluoride.

In the invention, the volume ratio of the vinyltriethoxysilane, hexamethyldisilazane and nano lanthanum trifluoride suspension is preferably 5:5: 100. In the invention, the temperature of the hydrothermal modification treatment is preferably 60-70 ℃; the time of the hydrothermal modification treatment is preferably 24-28 h. In the present invention, the hydrothermal modification treatment is preferably performed under stirring; the stirring speed is preferably 1500-1800 r/min.

After the hydrothermal modification treatment is finished, the product after the hydrothermal modification treatment is preferably subjected to filtration, washing, suction filtration and drying in sequence to obtain the modified nano lanthanum trifluoride. The operation of filtering, washing, suction filtering and drying is not particularly limited in the invention, and the technical scheme of filtering, washing, suction filtering and drying which is well known to those skilled in the art can be adopted. In the present invention, the filtration device is preferably a buchner funnel. In the present invention, the washing detergent is preferably ethanol; the number of suction filtration is preferably 3. In the invention, the drying temperature is preferably 60-70 ℃; the drying time is preferably 4 h; the drying mode is preferably vacuum drying.

The raw materials for preparing the component B comprise 12-20 parts of an auxiliary agent according to 10-28 parts of the chain extender. In the invention, the auxiliary agent preferably comprises 7-10 parts by weight of ethyl acetate, 2-3 parts by weight of a leveling agent, 1-2 parts by weight of a defoaming agent and 2-5 parts by weight of a silane coupling agent. In the present invention, the leveling agent is preferably AKN-3600; the antifoaming agent is preferably DU-964; the silane coupling agent is preferably KH 550.

In the present invention, the preparation method of the component B preferably includes: mixing the raw materials except the auxiliary agent, heating for 3-4 h at 90-102 ℃, adding the auxiliary agent, and stirring for 20-30 min to obtain a component B.

In the present invention, it is preferable to mix raw materials except the auxiliary agent to obtain a mixture. In the present invention, the mixing of the raw materials other than the auxiliary is preferably performed under stirring. In the invention, the stirring speed is preferably 1500-2000 r/min; the stirring time is preferably 30-50 min.

After the mixture is obtained, the mixture is preferably heated at 90-102 ℃ for 3-4 h to obtain the amino polymer. In the present invention, the temperature of the heating is preferably 90 ℃; the heating time is preferably 3 hours.

After the amino polymer is obtained, the invention preferably adds an auxiliary agent into the amino polymer, and stirs for 20-30 min to obtain the component B. In the invention, the stirring speed is preferably 1500-2000 r/min; the stirring time is preferably 20 min.

The adhesive force of the polyurea coating to the matrix is improved through the modified isocyanate, so that the impact resistance of the coating is improved; by adding the modified carbon nanofiber, the modified nano cerium trifluoride and the modified nano lanthanum trifluoride, the impact resistance of the polyurea coating is improved, the coating has super-hydrophobicity, the waterproof and anti-fouling performance of the coating is improved, and the bonding force and the wear resistance of the coating and the surface of a substrate can be improved by the modified cerium trifluoride, so that the coating can still keep extremely high tearing strength under high-speed impact; by adding the graphene, the impact resistance of the coating is further improved; by adding the flame retardant, the coating has stable and efficient flame retardant performance.

The invention also provides a preparation method of the multifunctional polyurea coating for the power battery tray, which comprises the following steps: and mixing the component A and the component B at 50-70 ℃, and spraying to obtain the multifunctional polyurea coating for the power battery tray.

The component A and the component B react at 50-70 ℃ to generate the polyurea coating, and then the polyurea coating is sprayed to obtain the multifunctional polyurea coating. In the present invention, the equipment used for spraying is preferably a high-pressure sprayer.

The component A and the component B are mixed and then sprayed to obtain the multifunctional polyurea coating for the power battery tray. The preparation method of the multifunctional polyurea coating for the power battery tray, provided by the invention, is simple to operate, and the performance of the polyurea coating is ensured.

The invention also provides the application of the multifunctional polyurea coating for the power battery tray or the multifunctional polyurea coating for the power battery tray prepared by the preparation method in the power battery tray. In the invention, the multifunctional polyurea coating is coated on the surface of the power battery tray, and plays a role in protecting the power battery tray.

The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example 1

The mass ratio of the component A to the component B is as follows: 1: 1.3;

the component A comprises the following raw materials in parts by weight:

50 parts of modified diphenylmethane diisocyanate, 200025 parts of polyoxypropylene glycol PPG, 8 parts of propylene carbonate DBGA, 5 parts of ammonium polyphosphate APP, 5 parts of melamine polyphosphate MPP and 7 parts of modified carbon nanofiber;

preparing carbon nanofiber CNF-OH with hydroxyl on the surface: putting 5g of carbon nanofibers (with the diameter of 120nm and the length of 10 microns) and 80mL of 75 wt% concentrated nitric acid into a 300mL single-neck round-bottom beaker provided with a magnetic rotor, carrying out ultrasonic treatment for 10min at 25kHz, installing a spherical condenser tube and a tail gas absorption tube, heating to 120 ℃, stirring and carrying out reflux reaction for 2h, diluting with 1000mL of deionized water after the reaction is finished, carrying out suction filtration by using a phi 0.22 micron mixed fiber microporous filter membrane, repeatedly washing with deionized water for multiple times until the carbon nanofibers are neutral, and carrying out vacuum drying for 24h at 80 ℃ to obtain acidified carbon nanofibers CNF-COOH;

putting 2g of acidified carbon nanofiber CNF-COOH and 80mL of thionyl chloride into a 300mL single-neck round-bottom beaker provided with a magnetic rotor, performing ultrasonic treatment for 10min at 25kHz, heating to 75 ℃, stirring, reacting for 24h under reflux, and performing reduced pressure distillation to remove excessive thionyl chloride to obtain acylated carbon nanofiber CNF-COCl;

putting 1.5g of carbon nanofiber acylate (CNF-COCl) and 80mL of ethylene glycol into a 300mL single-neck round-bottom beaker provided with a magnetic rotor, performing ultrasonic treatment for 10min at 25kHz, then reacting for 48h at 120 ℃, diluting with 1000mL of deionized water after the reaction is finished, performing suction filtration by using a mixed fiber microporous filter membrane with the diameter of phi 0.22 mu m to remove excessive ethylene glycol and byproducts, repeatedly washing with deionized water, and performing vacuum drying at 80 ℃ to obtain carbon nanofiber CNF-OH with hydroxyl on the surface;

preparing modified carbon nanofiber: 3g of carbon nanofiber CNF-OH with hydroxyl on the surface, 1mL of methyltrimethoxysilane MTMS and 3mL of H₂Placing the O in a closed reaction vessel, reacting for 10min at 25 ℃, and then placing in a dryer at 120 ℃ for drying for 6h to obtain modified carbon nanofibers;

preparation of modified diphenylmethane diisocyanate: adding 1g of carbon nanofiber CNF-OH with hydroxyl on the surface into 200g of diphenylmethane diisocyanate in a nitrogen-protected three-necked flask, carrying out ultrasonic treatment for 40min at 45kHz, and then stirring for 5h at a speed of 1800r/min to obtain modified diphenylmethane diisocyanate;

preparation of component A: adding modified diphenylmethane diisocyanate and PPG2000 into a reaction kettle, reacting for 3h at 60 ℃ in a nitrogen atmosphere, sequentially adding APP, MPP, modified carbon nanofiber and DBGA, and stirring for 4h at the speed of 2000r/min to obtain a component A, wherein the NCO value is 12%, and the viscosity is 750mPa & s.

The component B comprises the following raw materials in parts by weight:

20 parts of diethyl toluene diamine DETDA, 5 parts of N, N' -dialkyl methyl diamine, 200044 parts of amino-terminated polyether D, 2 parts of graphene powder, 1 part of azobisisobutyronitrile AIBN, 6 parts of modified nano cerium trifluoride, 3 parts of modified nano lanthanum trifluoride, 10 parts of N-butyl acetate, AKN-36002 parts of fluorocarbon modified acrylate flatting agent, DU-9642 parts of defoaming agent and KH 5505 parts of silane coupling agent;

preparing modified nano cerium trifluoride: dissolving 15g of nano cerium trifluoride in 25mL of magnesium hydroxysilicate at 80 ℃, uniformly stirring, adding 5g of oleic acid and 2g of polydimethylsiloxane, stirring for 1h, and drying for 5h at 120 ℃ to obtain modified cerium trifluoride;

preparing modified nano lanthanum trifluoride: mixing 15g of nano lanthanum trifluoride with 100mL of absolute ethyl alcohol, stirring for 1h by using a magnetic stirrer at the speed of 1500r/min to uniformly disperse the mixture, then adding ammonia water, and adjusting the pH value to be neutral to obtain a nano lanthanum trifluoride suspension; adding 5mL of vinyltriethoxysilane and 5mL of hexamethyldisilazane into the nanometer lanthanum trifluoride suspension, stirring at 60 ℃ for 24h at a speed of 1800r/min, filtering the obtained sample by using a Buchner funnel, repeatedly washing by using ethanol, carrying out suction filtration for 3 times, and carrying out vacuum drying at 60 ℃ for 4h to obtain modified nanometer lanthanum trifluoride;

preparation of component B: adding the raw materials except the auxiliary agent into a reaction kettle, stirring for 30min at the speed of 2000r/min, heating to 90 ℃ for 3h, sequentially adding ethyl acetate, a leveling agent AKN-3600, a defoaming agent DU-964 and a silane coupling agent KH550, and stirring for 20min at the speed of 1500r/min to obtain the component B.

Preparing a polyurea coating: and (3) uniformly mixing the component A and the component B in a dynamic mixing chamber at 60 ℃, then spraying by using a high-pressure spraying machine, and curing to obtain the multifunctional polyurea coating for the power battery tray. And (3) according to the specified conditions of the state regulation and test temperature and humidity of the GB9278-08-T coating sample, the polyurea coating is placed for 7 days for performance test, and the test results are shown in Table 1.

FIG. 1 is a schematic surface contact angle of the polyurea coating prepared in this example.

Example 2

The mass ratio of the component A to the component B is as follows: 1: 1.5;

the component A comprises the following raw materials in parts by weight:

50 parts of modified isophorone diisocyanate, 200010 parts of polyoxypropylene glycol PPG, 15 parts of flame-retardant polyether polyol POP3628H 15, 8 parts of propylene carbonate DBGA, 5 parts of trihydroxymethyl phosphine oxide THPO, 3 parts of melamine polyphosphate MPP and 9 parts of modified carbon nanofiber;

preparing modified isophorone diisocyanate: in a nitrogen-protected three-necked flask, 2g of the carbon nanofiber CNF-OH with hydroxyl on the surface prepared in example 1 is added into 200g of isophorone diisocyanate, ultrasonic treatment is carried out for 45min at 45kHz, and then stirring is carried out for 6h at the speed of 2000r/min to obtain modified isophorone diisocyanate;

preparation of component A: adding modified isophorone diisocyanate, PPG2000 and POP3628H into a reaction kettle, reacting for 3h at 60 ℃ in a nitrogen atmosphere, sequentially adding THPO, MPP, modified carbon nanofiber and DBGA, and stirring for 4h at the speed of 1800r/min to obtain a component A, wherein the NCO value is 14%, and the viscosity is 750 mPa.

The component B comprises the following raw materials in parts by weight:

20 parts of diethyl toluene diamine DETDA, 5 parts of N, N' -dialkyl methyl diamine, 200044 parts of amino-terminated polyether D, 2 parts of graphene powder, 1 part of azobisisobutyronitrile AIBN, 6 parts of modified nano cerium trifluoride, 3 parts of modified nano lanthanum trifluoride, 10 parts of N-butyl acetate, AKN-36002 parts of fluorocarbon modified acrylate flatting agent, DU-9642 parts of defoaming agent and KH 5505 parts of silane coupling agent;

preparation of component B: adding the raw materials except the auxiliary agent into a reaction kettle, stirring for 30min at the speed of 2000r/min, heating to 90 ℃ for 3h, sequentially adding ethyl acetate, a leveling agent AKN-3600, a defoaming agent DU-964 and a silane coupling agent KH550, and stirring for 20min at the speed of 2000r/min to obtain the component B.

Preparing a polyurea coating: and (3) uniformly mixing the component A and the component B in a dynamic mixing chamber at 50 ℃, then spraying by using a high-pressure spraying machine, and curing to obtain the multifunctional polyurea coating for the power battery tray. And (3) according to the specified conditions of the state regulation and test temperature and humidity of the GB9278-08-T coating sample, the polyurea coating is placed for 7 days for performance test, and the test results are shown in Table 1.

FIG. 2 is a schematic surface contact angle of the polyurea coating prepared in this example.

Example 3

The mass ratio of the component A to the component B is as follows: 1: 1.3;

the component A comprises the following raw materials in parts by weight:

47 parts of modified diphenylmethane diisocyanate, 20005 parts of polyoxypropylene glycol PPG, 10 parts of propylene carbonate DBGA, 10 parts of hyperbranched phosphorus-containing polyurethane HPPU and 10 parts of modified carbon nanofiber, wherein the PPG is present in the amount of less than ten percent, the POP3628H 18 is present in the amount of less than ten percent, and the modified carbon nanofiber is present in the amount of less than ten percent;

preparation of component A: adding modified diphenylmethane diisocyanate, PPG2000 and POP3628H into a reaction kettle, reacting for 3h at 60 ℃ in a nitrogen atmosphere, sequentially adding HPPU, modified carbon nanofiber and DBGA, and stirring for 4h at the speed of 2000r/min to obtain the component A, wherein the NCO value is 15%, and the viscosity is 800mPa & s.

The component B comprises the following raw materials in parts by weight:

10 parts of diethyl toluene diamine DETDA, 18 parts of N, N' -dialkyl methyl diamine, 500050 parts of amino-terminated polyether T, 1 part of graphene powder, 1 part of azobisisobutyronitrile AIBN, 4 parts of modified nano cerium trifluoride, 5 parts of modified nano lanthanum trifluoride, 7 parts of N-butyl acetate, AKN-36002 parts of fluorocarbon modified acrylate leveling agent, DU-9641 parts of defoaming agent and KH 5702 parts of silane coupling agent;

preparation of component B: adding the raw materials except the auxiliary agent into a reaction kettle, stirring for 30min at the speed of 2000r/min, heating to 90 ℃ for 3h, sequentially adding ethyl acetate, a leveling agent AKN-3600, a defoaming agent DU-964 and a silane coupling agent KH550, and stirring for 20min at the speed of 1800r/min to obtain the component B.

Preparing a polyurea coating: and (3) uniformly mixing the component A and the component B in a dynamic mixing chamber at 70 ℃, then spraying by using a high-pressure spraying machine, and curing to obtain the multifunctional polyurea coating for the power battery tray. And (3) according to the specified conditions of the state regulation and test temperature and humidity of the GB9278-08-T coating sample, the polyurea coating is placed for 7 days for performance test, and the test results are shown in Table 1.

FIG. 3 is a schematic surface contact angle of the polyurea coating prepared in this example.

TABLE 1 Performance test results for polyurea coatings prepared in examples 1-3

	Example 1	Example 2	Example 3
				Tensile Strength (MPa)	40	38	35
Elongation at Break (%)	450	420	380
				Tear Strength (kN/m)	121	103	123
Salt spray resistance (h)	2000	2000	2000
				UL-94 flame retardancy test	V0	V0	V0
Adhesion, 45 Steel (MPa)	16.57	18.67	17.56
				Contact angle (°)	153	150	155

The embodiment shows that the multifunctional polyurea coating for the power battery tray provided by the invention has super-hydrophobicity, high flame retardant property and extremely high impact resistance, the tensile strength is 40MPa, the elongation at break is 450%, the tear strength is 121kN/m, the contact angle is 153 degrees, the UL-94 flame retardant test is V0, the adhesion with 45 steel is 16.57MPa, and the salt spray resistance is 2000 h.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.