A new energy vehicle chassis foaming type heat preservation protective coating and a preparation method thereof

Abstract

The application belongs to the technical field of coating and specifically discloses a foaming type heat-insulating protective coating for new energy vehicle chassis and a preparation method thereof. The protective coating comprises 40-50 parts of polyurethane resin, 5-15 parts of epoxy resin, 10-20 parts of organic silicon resin, 15-25 parts of modified graphene nanomaterial, 3-4 parts of foaming agent, 1.0-2.5 parts of adhesion promoter, 3.5-6.5 parts of reinforcing agent, 6-17 parts of filler and 10-15 parts of dispersant. The foaming type heat-insulating protective coating for new energy vehicle chassis and the preparation method thereof are used, a compound foaming agent is used, heat transfer is effectively blocked, the coating has a low heat conductivity coefficient, the modified graphene nanomaterial improves the dispersivity and interface bonding force of graphene in the coating matrix, the coating toughness, impact strength and wear resistance are improved, the organic silicon resin and the reinforcing agent are synergistic, the coating has excellent high-temperature resistance, and there is no yellowing, cracking and falling-off phenomenon.

Description

Technical Field

[0001] This invention relates to the field of coating technology, and in particular to a foamed thermal insulation and protective coating for the chassis of new energy vehicles and its preparation method. Background Technology

[0002] The core three-electric system (battery, motor, and electronic control) of new energy vehicles has much higher requirements for chassis operating environment temperature stability, insulation, and protection than those of traditional fuel vehicles. The optimal operating temperature range for power batteries is 25-40℃. In low-temperature environments, battery capacity decays and charging efficiency drops sharply, while in high-temperature environments, thermal runaway risks are easily triggered. At the same time, the vehicle chassis is exposed to the outdoors for a long time and must withstand complex conditions such as gravel impact, rain immersion, alternating high and low temperatures, and mud and sand corrosion.

[0003] Existing automotive chassis coatings are mostly ordinary stone chip protection coatings and PVC foam protective coatings, which have obvious technical defects: poor thermal insulation performance, no controllable microporous foam structure, and inability to effectively block the temperature interference of external high and low temperatures on the chassis and battery compartment. The insulation effect is weak in winter low temperature and summer heat insulation; the resistance to temperature alternation is weak, and long-term use is prone to cracking and powdering, which cannot meet the safety protection requirements of the three-electric system of new energy vehicles.

[0004] Existing patents and market products mostly focus on single-function stone impact resistance, without designing exclusive formulas and foaming processes for the complex needs of new energy vehicle chassis insulation, weather resistance, and damage resistance. As a result, they suffer from single-function, poor adaptability to working conditions, and insufficient performance stability. Therefore, there is an urgent need to develop a targeted foamed thermal insulation and protective coating for new energy vehicle chassis. Summary of the Invention

[0005] The purpose of this invention is to provide a foamed thermal insulation and protective coating for the chassis of new energy vehicles and its preparation method. The proportions of each raw material are reasonable, and the resin, functional filler, foaming system and additives form a good synergistic effect. It takes into account multiple core properties such as thermal insulation, protection, corrosion prevention, temperature resistance and adhesion, and makes up for the defects of traditional chassis coatings that have outstanding single properties and obvious shortcomings in comprehensive performance, so as to fully meet the integrated protection needs of new energy vehicle chassis.

[0006] To achieve the above objectives, the present invention provides a foamed thermal insulation and protective coating for the chassis of new energy vehicles, comprising 40-50 parts of polyurethane resin, 5-15 parts of epoxy resin, 10-20 parts of silicone resin, 15-25 parts of modified graphene nanomaterials, 3-4 parts of foaming agent, 1.0-2.5 parts of adhesion promoter, 3.5-6.5 parts of reinforcing agent, 6-17 parts of filler, and 10-15 parts of dispersant.

[0007] Preferably, the adhesion promoter includes hydroxyl-terminated polydimethylsiloxane, methyltriethoxysilane, and silane coupling agent KH-550, with the mass ratio of hydroxyl-terminated polydimethylsiloxane, methyltriethoxysilane, and silane coupling agent KH-550 being 3:2:(0.05-0.08).

[0008] Preferably, the dispersant comprises propylene glycol methyl ether acetate and xylene, wherein the mass ratio of propylene glycol methyl ether acetate to xylene is 1:1.

[0009] Preferably, the foaming agent is a composite microsphere foaming agent, which is a mixture of thermally expandable acrylate microsphere foaming agent and sodium bicarbonate micro powder at a mass ratio of 2:1, with a microsphere particle size of 20-40μm.

[0010] Preferably, the reinforcing agent includes polyaniline and nano-titanium dioxide.

[0011] Preferably, the filler includes mica powder and fumed silica.

[0012] This invention also provides a method for preparing a foamed thermal insulation and protective coating for the chassis of new energy vehicles, comprising the following steps: Step 1: Modified graphene nanomaterials. Expandable graphite is thermally expanded at 800℃ for 1 min, then ultrasonically exfoliated in anhydrous ethanol for 48 h and dried. D2000 polyetheramine and N,N-dimethylformamide are added and mixed. After ball milling for 8 h, it is mixed with the dehydrated D2000 polyetheramine / T5000 polyetheramine mixture and subjected to isocyanate reaction for 3 h under nitrogen protection. After stirring, polyaspartic acid ester is introduced and thermosetting is formed. Step 2, adhesion promoter: Under nitrogen protection, hydroxyl-terminated polydimethylsiloxane and methyltriethoxysilane are mixed and condensed at 120°C for 2 hours using dibutyltin dilaurate as a catalyst. Then, it is mixed with silane coupling agent KH-550, filler and dispersant. Step 3, Enhancer: Adjust the pH of the nano-titanium dioxide aqueous solution to 2-3, add aniline, stir and sonicate, add ammonium persulfate aqueous solution and stir to react, then filter, wash and dry; Step 4: After mixing polyurethane resin, silicone resin, epoxy resin, adhesion promoter and deionized water, the mixture is subjected to high-speed shearing treatment to obtain the composite matrix. Step 5: Add modified graphene nanomaterials and reinforcing agents to the composite matrix, mix them evenly, and then grind them to a fineness of <30µm to obtain a functional composite slurry. Step 6: Add composite microsphere foaming agent to the functional composite slurry, keep it at a constant temperature of 40℃ and stir at a low speed of 500r / min for 8-10 minutes, filter and discharge to obtain the finished foamed thermal insulation and protective coating.

[0013] Preferably, in step 1, the mass ratio of expandable graphite to D2000 polyetheramine is 1:15.

[0014] Preferably, in step 1, the isocyanate esterification reaction is pre-reacted in an ice bath for 30 minutes, followed by heating to 80°C and then in an oil bath for 30 minutes.

[0015] Preferably, in step 3, the mass ratio of nano-titanium dioxide to water in the nano-titanium dioxide aqueous solution is 1:28, and the amount of aniline added is twice the mass of nano-titanium dioxide.

[0016] The advantages and beneficial effects of the above-mentioned foamed thermal insulation and protective coating for new energy vehicle chassis and its preparation method are as follows: 1. This invention utilizes a composite foaming agent made from thermally expandable acrylate microspheres and sodium bicarbonate. After foaming, a continuous, uniform, and closed microporous structure is formed inside the coating, effectively blocking heat transfer and resulting in a low thermal conductivity coating. This provides excellent insulation for the chassis and battery compartment components of new energy vehicles, reducing power battery energy loss in low-temperature environments. Simultaneously, it isolates the chassis from high road surface temperatures, ensuring the stable operation of the vehicle's thermal management system.

[0017] 2. This invention utilizes graphene nanomaterials modified with polyetheramine and polyaspartic acid ester, which improves the dispersibility and interfacial bonding of graphene in the coating matrix, significantly enhancing the coating's toughness, impact resistance, and wear resistance. During vehicle operation, the coating effectively resists high-speed impacts and friction from gravel and mud, preventing scratches and dents on the chassis metal substrate and extending the chassis's service life.

[0018] 3. This invention utilizes a ternary resin compound of polyurethane, epoxy resin, and silicone resin to construct a dense protective coating film. Combined with the physical shielding and chemical corrosion protection effects of polyaniline and nano-titanium dioxide composite reinforcing agents and modified graphene, the coating film exhibits extremely low water and oxygen permeability. After 1000 hours of neutral salt spray testing, no rust or peeling was observed, demonstrating its resistance to corrosion from rain, snow, de-icing salt, and humid air.

[0019] 4. This invention employs an adhesion promoter formulated with hydroxyl-terminated polydimethylsiloxane, methyltriethoxysilane, and a silane coupling agent. This promoter forms chemical bonds between the coating and the cold-rolled steel substrate of the automotive chassis, achieving a paint film adhesion rating of 0. Even after prolonged exposure to vehicle vibration and temperature cycling, peeling, cracking, and flaking will not occur, significantly improving protective durability. The synergistic effect of the silicone resin and composite reinforcing agent imparts excellent high-temperature resistance to the coating, showing no yellowing, cracking, or flaking even after prolonged baking at 180°C.

[0020] The technical solution of the present invention will be further described in detail below through embodiments. Detailed Implementation

[0021] The technical solution of the present invention will be further described below through embodiments.

[0022] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains.

[0023] The following examples are not intended to limit the invention, but are only for illustration. Unless otherwise specified, the experimental methods used in the following examples are generally performed under conventional conditions. Unless otherwise specified, the materials and reagents used in the following examples are commercially available.

[0024] Example 1 A foamed thermal insulation and protective coating for the chassis of a new energy vehicle, characterized in that it comprises 45 parts of polyurethane resin, 10 parts of epoxy resin, 15 parts of silicone resin, 20 parts of modified graphene nanomaterials, 3.5 parts of foaming agent, 1.9 parts of adhesion promoter, 4.8 parts of reinforcing agent, 14 parts of filler, and 13 parts of dispersant.

[0025] Polyurethane resin viscosity 2500-3000 mPa·s (25℃); Epoxy resin: E-51 type bisphenol A epoxy resin; Organosilicon resin: methyl phenyl organosilicon resin, solid content ≥98%; Modified graphene nanomaterials: self-made modified powder, particle size 50-100 nm; Foaming agent: thermally expandable acrylate microsphere foaming agent (particle size 20-40 μm) and sodium bicarbonate micro powder (particle size 30-50 μm) in a mass ratio of 2:1; Adhesion Accelerators: Hydroxyl-terminated polydimethylsiloxane, methyltriethoxysilane, and silane coupling agent KH-550 in a mass ratio of 3:2:0.065; Dispersant: Propylene glycol methyl ether acetate and xylene in a 1:1 mass ratio; Reinforcing agents: Polyaniline (conductive grade, particle size 20-30nm), nano-titanium dioxide (rutile type, particle size 15-25nm); Fillers: Mica powder (800 mesh), fumed silica (hydrophobic type, specific surface area 200-300m²). 2 / g).

[0026] A method for preparing a foamed thermal insulation and protective coating for the chassis of a new energy vehicle includes the following steps: Step 1: Preparation of modified graphene nanomaterials: Expandable graphite was thermally expanded at 800℃ for 1 min and then naturally cooled to room temperature. The expanded graphite was placed in anhydrous ethanol and ultrasonically exfoliated for 48 h (ultrasonic power 300W, frequency 40kHz), and then vacuum dried at 60℃ for 12 h. The expandable graphite and D2000 polyetheramine were mixed at a mass ratio of 1:15, and an appropriate amount of N,N-dimethylformamide was added as a dispersion medium. The mixture was then ball-milled for 8 h (speed 300r / min). The ball-milled material was mixed with a dehydrated D2000 / T5000 polyetheramine mixture (mass ratio 2:1), and an isocyanate esterification reaction was carried out at 85℃ for 3 h under nitrogen protection (pre-reaction in an ice bath for 30 min, followed by an oil bath at 80℃ for 30 min). After the reaction, polyaspartic acid ester (8% of the total mass of the modified system) was introduced under uniform stirring, and the mixture was thermally cured at 120℃ for 2 h. The resulting modified graphene nanomaterials were then pulverized and ground for later use.

[0027] Step 2: Preparation of adhesion promoter: Under nitrogen atmosphere protection, mix the prepared hydroxyl-terminated polydimethylsiloxane and methyltriethoxysilane, add 0.2% of dibutyltin dilaurate catalyst by total mass, and condense at 120℃ for 2 hours. After the reaction is completed, cool naturally to room temperature, add silane coupling agent KH-550, some filler and dispersant in sequence, stir at low speed for 30 minutes to mix evenly, and set aside.

[0028] Step 3: Preparation of reinforcing agent: Prepare a 10% aqueous solution of nano-titanium dioxide and deionized water, and adjust the pH value to 2-3 with dilute hydrochloric acid; add aniline (mass ratio of nano-titanium dioxide to aniline 5:2), stir for 20 min and then ultrasonically disperse for 15 min; slowly add ammonium persulfate aqueous solution (molar ratio of ammonium persulfate to aniline 1.2:1), stir and react at room temperature for 4 h; after the reaction is completed, filter, wash with deionized water and anhydrous ethanol alternately 3 times, vacuum dry at 80℃ for 8 h, and grind to obtain composite reinforcing agent powder.

[0029] Step 4: Preparation of composite matrix: Mix polyurethane resin, silicone resin, epoxy resin, adhesion promoter and appropriate amount of deionized water, and disperse by high-speed shear for 25 min (rotation speed 8000 r / min, room temperature) to obtain a uniform composite matrix.

[0030] Step 5: Preparation of functional composite slurry: Add modified graphene nanomaterials and composite reinforcing agent to the composite matrix in sequence, stir at medium speed for 40 minutes to mix evenly; transfer to a sand mill for grinding, control the temperature ≤40℃ throughout the process, and grind until the slurry fineness is <30μm to obtain the functional composite slurry.

[0031] Step 6: Finished product preparation: Add composite microsphere foaming agent to the functional composite slurry, keep it at a constant temperature of 40℃ and stir at a low speed of 500r / min for 9min, filter it through a 200-mesh filter and get the finished product of foamed thermal insulation and protective coating for new energy vehicle chassis.

[0032] Example 2 A foamed thermal insulation and protective coating for the chassis of a new energy vehicle comprises 40 parts of polyurethane resin, 5 parts of epoxy resin, 10 parts of silicone resin, 15 parts of modified graphene nanomaterials, 3 parts of foaming agent, 1.0 part of adhesion promoter, 3.5 parts of reinforcing agent, 6 parts of filler, and 10 parts of dispersant.

[0033] A method for preparing a foamed thermal insulation and protective coating for the chassis of a new energy vehicle includes the following steps: Step 1: Preparation of modified graphene nanomaterials: Expandable graphite was thermally expanded at 800℃ for 1 min and then naturally cooled to room temperature. The expanded graphite was placed in anhydrous ethanol and ultrasonically exfoliated for 48 h (ultrasonic power 350W, frequency 35kHz), and then vacuum dried at 65℃ for 10 h. The expandable graphite and D2000 polyetheramine were mixed at a mass ratio of 1:15, and an appropriate amount of N,N-dimethylformamide was added as a dispersion medium. The mixture was then ball-milled for 8 h (speed 400r / min). The ball-milled material was mixed with a dehydrated D2000 / T5000 polyetheramine mixture (mass ratio 2:1), and an isocyanate esterification reaction was carried out under nitrogen protection at 85℃ (pre-reaction in an ice bath for 30 min, followed by an oil bath at 80℃ for 30 min) for 3 h. After the reaction, polyaspartic acid ester (addition amount of 9% of the total mass of the modified system) was introduced under uniform stirring, and the mixture was thermally cured at 120℃ for 2 h. The resulting modified graphene nanomaterials were then pulverized and ground for later use.

[0034] Step 2: Preparation of adhesion promoter: Under nitrogen atmosphere protection, mix the prepared hydroxyl-terminated polydimethylsiloxane and methyltriethoxysilane, add 0.2% of dibutyltin dilaurate catalyst by total mass, and condense at 120℃ for 2 hours. After the reaction is completed, cool naturally to room temperature, add silane coupling agent KH-550, some filler and dispersant in sequence, stir at low speed for 30 minutes to mix evenly, and set aside.

[0035] Step 3: Preparation of reinforcing agent: Prepare a 10% aqueous solution of nano-titanium dioxide and deionized water, and adjust the pH value to 2-3 with dilute hydrochloric acid; add aniline (nano-titanium dioxide to aniline mass ratio 5:2), stir for 20 min and then ultrasonically disperse for 15 min; slowly add ammonium persulfate aqueous solution (ammonium persulfate to aniline molar ratio 1.4:1), stir and react at room temperature for 4 h; after the reaction is completed, filter, wash with deionized water and anhydrous ethanol alternately 3 times, vacuum dry at 80℃ for 8 h, and grind to obtain composite reinforcing agent powder.

[0036] Step 4: Preparation of composite matrix: Mix polyurethane resin, silicone resin, epoxy resin, adhesion promoter and appropriate amount of deionized water, and disperse at high speed by shear for 22 min (rotation speed 8200 r / min, room temperature) to obtain a uniform and transparent composite matrix.

[0037] Step 5: Preparation of functional composite slurry: Add modified graphene nanomaterials and composite reinforcing agent to the composite matrix in sequence, stir at medium speed for 40 minutes to mix evenly; transfer to a sand mill for grinding, control the temperature ≤40℃ throughout the process, and grind until the slurry fineness is <30μm to obtain the functional composite slurry.

[0038] Step 6: Finished product preparation: Add composite microsphere foaming agent to the functional composite slurry, keep it at a constant temperature of 40℃ and stir at a low speed of 500r / min for 8 minutes, filter it through a 200-mesh filter to obtain the finished product of foamed thermal insulation and protective coating for new energy vehicle chassis.

[0039] Example 3 A foamed thermal insulation and protective coating for the chassis of a new energy vehicle, characterized in that it comprises 50 parts of polyurethane resin, 15 parts of epoxy resin, 20 parts of silicone resin, 25 parts of modified graphene nanomaterials, 4 parts of foaming agent, 2.5 parts of adhesion promoter, 6.5 parts of reinforcing agent, 17 parts of filler, and 15 parts of dispersant.

[0040] A method for preparing a foamed thermal insulation and protective coating for the chassis of a new energy vehicle includes the following steps: Step 1: Preparation of modified graphene nanomaterials: Expandable graphite was thermally expanded at 800℃ for 1 min and then naturally cooled to room temperature. The expanded graphite was placed in anhydrous ethanol and ultrasonically exfoliated for 48 h (ultrasonic power 400W, frequency 45kHz), and then vacuum dried at 70℃ for 10 h. The expandable graphite and D2000 polyetheramine were mixed at a mass ratio of 1:15, and an appropriate amount of N,N-dimethylformamide was added as a dispersion medium. The mixture was then ball-milled for 8 h (speed 400r / min). The ball-milled material was mixed with a dehydrated D2000 / T5000 polyetheramine mixture (mass ratio 2:1), and an isocyanate esterification reaction was carried out at 85℃ for 3 h under nitrogen protection (pre-reaction in an ice bath for 30 min, followed by an oil bath at 80℃ for 30 min). After the reaction, polyaspartic acid ester (8% of the total mass of the modified system) was introduced under uniform stirring, and the mixture was thermally cured at 120℃ for 2 h. The resulting modified graphene nanomaterials were then pulverized and ground for later use.

[0041] Step 2: Preparation of adhesion promoter: Under nitrogen atmosphere protection, mix the prepared hydroxyl-terminated polydimethylsiloxane and methyltriethoxysilane, add 0.2% of dibutyltin dilaurate catalyst by total mass, and condense at 120℃ for 2 hours. After the reaction is completed, cool naturally to room temperature, add silane coupling agent KH-550, some filler and dispersant in sequence, stir at low speed for 30 minutes to mix evenly, and set aside.

[0042] Step 3: Preparation of reinforcing agent: Prepare a 10% aqueous solution of nano-titanium dioxide and deionized water, and adjust the pH value to 2-3 with dilute hydrochloric acid; add aniline (mass ratio of nano-titanium dioxide to aniline 5:2), stir for 20 min and then ultrasonically disperse for 15 min; slowly add ammonium persulfate aqueous solution (molar ratio of ammonium persulfate to aniline 1.2:1), stir and react at room temperature for 4 h; after the reaction is completed, filter, wash with deionized water and anhydrous ethanol alternately 3 times, vacuum dry at 80℃ for 8 h, and grind to obtain composite reinforcing agent powder.

[0043] Step 4: Preparation of composite matrix: Mix polyurethane resin, silicone resin, epoxy resin, adhesion promoter and appropriate amount of deionized water, and disperse by high-speed shear for 25 min (rotation speed 8000 r / min, room temperature) to obtain a uniform and transparent composite matrix.

[0044] Step 5: Preparation of functional composite slurry: Add modified graphene nanomaterials and composite reinforcing agent to the composite matrix in sequence, stir at medium speed for 40 minutes to mix evenly; transfer to a sand mill for grinding, control the temperature ≤40℃ throughout the process, and grind until the slurry fineness is <30μm to obtain the functional composite slurry.

[0045] Step 6: Finished product preparation: Add composite microsphere foaming agent to the functional composite slurry, keep it at a constant temperature of 40℃ and stir at a low speed of 500r / min for 10min, filter it through a 200-mesh filter and get the finished product of foamed thermal insulation and protective coating for new energy vehicle chassis.

[0046] Comparative Example 1 The difference from Example 1 is the removal of the modified graphene nanomaterial; otherwise, the contents are the same as in Example 1.

[0047] Comparative Example 2 Unlike Example 1, a single foaming agent was used, specifically a thermally expanding acrylate microsphere foaming agent (3.5 parts), and sodium bicarbonate micropowder was removed. The rest of the process was the same as in Example 1.

[0048] Comparative Example 3 The difference from Example 1 is that the reinforcing agent is removed, but the rest is the same as Example 1.

[0049] Comparative Example 4 The difference from Example 1 is that the adhesion promoter is replaced with silane coupling agent KH-550, while the rest is the same as in Example 1.

[0050] The protective coatings of Examples 1-3 and Comparative Examples 1-4 were subjected to performance tests, and the test results are shown in Table 1.

[0051] All samples were sprayed onto the surface of cold-rolled steel sheet specifically for new energy vehicle chassis, with a dry film thickness of 80μm. Performance testing was conducted after curing at room temperature for 7 days.

[0052] Table 1 Test Results

[0053] After replacing ordinary graphene in Comparative Example 1, the impact resistance and corrosion resistance of the coating decreased significantly, proving that the self-made modified graphene nanomaterial of this invention can significantly improve the mechanical strength and anti-corrosion performance of the coating, and solve the defects of poor dispersibility and weak bonding force with the matrix of ordinary graphene.

[0054] Comparative Example 2 used a single foaming agent, which increased the thermal conductivity of the coating, decreased its thermal insulation performance, and resulted in poor foaming uniformity. This demonstrates that the composite foaming agent, which combines acrylate microspheres and sodium bicarbonate, can form a dense and uniform microporous structure, significantly improving the thermal insulation effect.

[0055] In Comparative Example 3, the high-temperature stability and corrosion resistance of the coating were significantly reduced after the removal of the polyaniline / nano titanium dioxide reinforcing agent, proving that the composite reinforcing agent can work synergistically with organosilicon and epoxy resin to build a stable protective system and improve the coating's high-temperature resistance, anti-aging, and corrosion resistance.

[0056] Comparative Example 4 used a single silane coupling agent, and the adhesion and durability of the coating substrate were significantly worse, proving that the ternary compound adhesion promoter of the present invention can effectively improve the interlayer bonding force between the coating and the automotive chassis substrate, and avoid peeling and flaking after long-term use.

[0057] Example 1 achieves optimal balance through synergistic effects of each component. Compared to the high and low ratio examples, it combines excellent thermal insulation, corrosion resistance, impact resistance, and high temperature resistance. At the same time, the slurry has the best fluidity and workability, making it suitable for industrial spraying of new energy vehicle chassis.

[0058] The interpenetrating network structure of silicone and epoxy resins, through the cross-linking and interpenetration of rigid and flexible segments, enhances the high-temperature crack resistance and corrosion resistance of the modified high-temperature resistant and anti-corrosion coating while maintaining its high-temperature stability, thus achieving a comprehensive improvement in both high-temperature insulation and anti-corrosion performance. In the reinforcing agent, polyaniline can absorb electrons from the metal matrix surface to form metal cations in acidic or alkaline environments, while simultaneously releasing electrons to generate OH-. -This process generates a dense oxide passivation film on the surface of the metal substrate. During this process, polyaniline itself undergoes a reversible redox reaction and is not consumed, thus enhancing the corrosion resistance of the modified high-temperature resistant heat-insulating and anti-corrosion coating in complex corrosive environments. Nano-metal oxides can inhibit chemical corrosion.

[0059] Therefore, the present invention adopts the above-mentioned foamed thermal insulation and protective coating for new energy vehicle chassis and its preparation method. The proportion of each raw material component is reasonable, and the resin, functional filler, foaming system and additives form a good synergistic effect. It takes into account multiple core properties such as thermal insulation, protection, corrosion prevention, temperature resistance and adhesion, and makes up for the defects of traditional chassis coatings that have outstanding single performance and obvious shortcomings in comprehensive performance, and fully meets the integrated protection needs of new energy vehicle chassis.

[0060] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A foamed thermal insulation and protective coating for the chassis of new energy vehicles, characterized in that: It includes 40-50 parts of polyurethane resin, 5-15 parts of epoxy resin, 10-20 parts of silicone resin, 15-25 parts of modified graphene nanomaterials, 3-4 parts of foaming agent, 1.0-2.5 parts of adhesion promoter, 3.5-6.5 parts of reinforcing agent, 6-17 parts of filler, and 10-15 parts of dispersant.

2. The foamed thermal insulation and protective coating for the chassis of a new energy vehicle according to claim 1, characterized in that: The adhesion promoters include hydroxyl-terminated polydimethylsiloxane, methyltriethoxysilane, and silane coupling agent KH-550, with a mass ratio of 3:2:(0.05-0.08) for hydroxyl-terminated polydimethylsiloxane, methyltriethoxysilane, and silane coupling agent KH-550.

3. The foamed thermal insulation and protective coating for the chassis of a new energy vehicle according to claim 1, characterized in that: The dispersant includes propylene glycol methyl ether acetate and xylene, with a mass ratio of propylene glycol methyl ether acetate to xylene of 1:

1.

4. The foamed thermal insulation and protective coating for the chassis of a new energy vehicle according to claim 1, characterized in that: The foaming agent is a composite microsphere foaming agent, which is a thermally expandable acrylate microsphere foaming agent and sodium bicarbonate micro powder mixed at a mass ratio of 2:1, with a microsphere particle size of 20-40μm.

5. The foamed thermal insulation and protective coating for the chassis of a new energy vehicle according to claim 1, characterized in that: The reinforcing agents include polyaniline and nano-titanium dioxide.

6. The foamed thermal insulation and protective coating for the chassis of a new energy vehicle according to claim 1, characterized in that: The fillers include mica powder and fumed silica.

7. A method for preparing a foamed thermal insulation and protective coating for a new energy vehicle chassis according to any one of claims 1-6, characterized in that, Includes the following steps: Step 1: Modified graphene nanomaterials. Expandable graphite is thermally expanded at 800℃ for 1 min, then ultrasonically exfoliated in anhydrous ethanol for 48 h and dried. D2000 polyetheramine and N,N-dimethylformamide are added and mixed. After ball milling for 8 h, it is mixed with the dehydrated D2000 polyetheramine / T5000 polyetheramine mixture and subjected to isocyanate reaction for 3 h under nitrogen protection. After stirring, polyaspartic acid ester is introduced and thermosetting is formed. Step 2, adhesion promoter: Under nitrogen protection, hydroxyl-terminated polydimethylsiloxane and methyltriethoxysilane are mixed and condensed at 120°C for 2 hours using dibutyltin dilaurate as a catalyst. Then, it is mixed with silane coupling agent KH-550, filler and dispersant. Step 3, Enhancer: Adjust the pH of the nano-titanium dioxide aqueous solution to 2-3, add aniline, stir and sonicate, add ammonium persulfate aqueous solution and stir to react, then filter, wash and dry; Step 4: After mixing polyurethane resin, silicone resin, epoxy resin, adhesion promoter and deionized water, the mixture is subjected to high-speed shearing treatment to obtain the composite matrix. Step 5: Add modified graphene nanomaterials and reinforcing agents to the composite matrix, mix them evenly, and then grind them to a fineness of <30µm to obtain a functional composite slurry. Step 6: Add composite microsphere foaming agent to the functional composite slurry, keep it at a constant temperature of 40℃ and stir at a low speed of 500r / min for 8-10 minutes, filter and discharge to obtain the finished foamed thermal insulation and protective coating.

8. The preparation method of a foamed thermal insulation and protective coating for a new energy vehicle chassis according to claim 7, characterized in that: In step 1, the mass ratio of expandable graphite to D2000 polyetheramine is 1:

15.

9. The preparation method of a foamed thermal insulation and protective coating for a new energy vehicle chassis according to claim 7, characterized in that: In step 1, the isocyanate esterification reaction is pre-reacted in an ice bath for 30 minutes, followed by heating to 80°C in an oil bath for 30 minutes.

10. The preparation method of a foamed thermal insulation and protective coating for a new energy vehicle chassis according to claim 7, characterized in that: In step 3, the mass ratio of nano-titanium dioxide to water in the nano-titanium dioxide aqueous solution is 1:28, and the amount of aniline added is twice the mass of nano-titanium dioxide.

Images