Lightweight re-coating material for automobiles and preparation method thereof

Abstract

The application belongs to the technical field of coating and discloses a lightweight recoating material for automobiles and a preparation method thereof. The lightweight recoating material for automobiles comprises the following raw materials in parts by mass: polyvinyl chloride paste resin 27-29 parts, mixed polyvinyl chloride resin 3-3.5 parts, diisononyl phthalate 22-26 parts, adhesion promoter 1.5-1.7 parts, viscosity reducer 3-3.5 parts, calcium oxide 5-5.5 parts, modified silicon dioxide 3-3.5 parts, zinc oxide 2-2.5 parts, active nano calcium carbonate 17-22 parts, heavy calcium 5-6 parts, modified titanium dioxide microspheres 1.5-2 parts, and foaming agent 0.8-1 part. In the application, the introduction of the modified silicon dioxide and the modified titanium dioxide microspheres also effectively improves the impact resistance, stone resistance, weather resistance, high-temperature resistance and corrosion resistance of the lightweight recoating material for automobiles. Therefore, the application has a more extensive application prospect.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of coatings, and particularly relates to a lightweight heavy coating material for automobiles and a preparation method thereof. BACKGROUND

[0002] The lightweight coating material for automobiles is a new type of automobile coating that can significantly reduce the weight per unit area of the coating while ensuring the core functions of traditional automobile coatings such as scratch resistance and decoration. Compared with traditional coatings, the core advantage of the lightweight coating material is that it can reduce weight without compromising performance, avoiding the increase in vehicle weight caused by excessive coating thickness, and fully meeting the rigid requirements of the automobile coating for protection and decoration. This type of material is commonly used in vehicle key components such as the body, chassis, and new energy automobile battery pack.

[0003] However, in practical applications, the lightweight coating material for automobiles still has obvious shortcomings: first, the anti-stone impact performance is insufficient, especially for the coating on the chassis and lower part of the body, which has weak protective ability when facing road stone impact; second, the high temperature resistance is poor, and softening deformation easily occurs in high temperature environment; third, the weather resistance and corrosion resistance are poor, and the coating is prone to discoloration, pitting, and blistering after long-term exposure to sunlight and rain. Moreover, existing technologies mainly focus on optimizing a single aspect of performance, making it difficult for the lightweight coating material to simultaneously possess excellent impact resistance, stone impact resistance, weather resistance, high temperature resistance, and corrosion resistance. Therefore, the stone impact resistance, weather resistance, high temperature resistance, and corrosion resistance of existing lightweight coating materials still need to be further improved simultaneously. SUMMARY

[0004] To solve the problems mentioned in the background, the present application aims to provide a lightweight heavy coating material for automobiles and a preparation method thereof, which solves the following technical problems:

[0005] The existing lightweight coating material still has the problem of poor comprehensive effect of stone impact resistance, weather resistance, high temperature resistance, and corrosion resistance.

[0006] The purpose of the present application can be achieved by the following technical solutions:

[0007] A lightweight heavy coating material for automobiles, comprising the following raw materials by mass: polyvinyl chloride paste resin 27-29 parts, blended polyvinyl chloride resin 3-3.5 parts, diisononyl phthalate 22-26 parts, adhesion promoter 1.5-1.7 parts, viscosity reducer 3-3.5 parts, calcium oxide 5-5.5 parts, modified silicon dioxide 3-3.5 parts, zinc oxide 2-2.5 parts, active nano calcium carbonate 17-22 parts, heavy calcium 5-6 parts, modified titanium dioxide microspheres 1.5-2 parts, and foaming agent 0.8-1 part.

[0008] The modified silica is porous hollow silica microspheres which are first grafted with 3-aminopropyltriethoxysilane to form an amino transition layer, and then are formed with a uniform Fe-C layer by Fe catalytic carbon growth under a hydrogen-nitrogen-acetylene mixed atmosphere at 650-700℃ with ferrocene xylene solution as the Fe source and acetylene gas as the carbon source; the porous hollow silica microspheres are prepared by using polyacrylic acid-N,N'-methylene bisacrylamide gel as the main template and cetyltrimethylammonium bromide as the secondary template, and by hydrolysis and condensation of tetraethyl orthosilicate and calcination under an air atmosphere at 550℃;

[0009] The modified titanium dioxide microspheres are prepared from dicyclopentadiene, pretreated titanium dioxide, toluene-2,4-diisocyanate, dibutyltin dilaurate, tert-butyl benzoyl peroxide, polyvinyl alcohol 1788, deionized water and ethylenediamine; the pretreated titanium dioxide is nano titanium dioxide grafted with octadecylamine.

[0010] Preferably, the modified silica is prepared by the following method:

[0011] A1: polyacrylic acid aqueous solution is added to deionized water and stirred uniformly, the pH is adjusted to 2.5-3.0, then the temperature is raised to 60℃ and N,N'-methylene bisacrylamide and ammonium persulfate are added, the mixture is stirred for 30-40 min, then the pH is adjusted to 9, cetyltrimethylammonium bromide is added and stirred for 30-40 min, then tetraethyl orthosilicate is added dropwise at 60℃ and stirred for 12-14 h, after cooling, the mixture is stirred for 4-5 h, the precipitate is centrifuged, washed, freeze-dried, calcined under an air atmosphere at 550℃ for 5-6 h, and then cooled to obtain porous hollow silica microspheres;

[0012] A2: the porous hollow silica microspheres are dispersed in ethanol, then 3-aminopropyltriethoxysilane is added and refluxed at 60℃ for 3-4 h, the precipitate is centrifuged, washed and vacuum dried to obtain aminated silica;

[0013] A3: the aminated silica is laid flat in a quartz boat and placed in the constant temperature zone of a tube furnace, first heated to 450℃ under a nitrogen atmosphere and kept for 30-40 min, then kept for 30-40 min under a mixed gas atmosphere of hydrogen and nitrogen, then heated to 650-700℃ and ferrocene xylene solution is injected into the 220℃ vaporization zone at the front end of the quartz tube while acetylene is introduced and kept for 30-40 min, then the acetylene and injection pump are turned off and the temperature is lowered to 100-200℃, and finally cooled under a pure nitrogen atmosphere to obtain the modified silica.

[0014] Preferably, the mass ratio of the deionized water, polyacrylic acid aqueous solution, N,N'-methylene bisacrylamide, ammonium persulfate, cetyltrimethylammonium bromide and tetraethyl orthosilicate in A1 is 200-250:100:0.5:0.1:2:20;

[0015] The mass fraction of the polyacrylic acid aqueous solution in A1 is 10%.

[0016] Preferably, the mass ratio of the porous hollow silica microspheres, ethanol, and 3-aminopropyl triethoxysilane in A2 is 2:100-120:0.4-0.8.

[0017] Preferably, the ratio of the amount of use of the aminated silica and the xylene solution of ferrocene in A3 is 2g:20-30mL.

[0018] The concentration of the xylene solution of ferrocene in A3 is 0.05g / mL.

[0019] The flow rate of hydrogen in the hydrogen-nitrogen mixed gas in A3 is 200sccm, and the flow rate of nitrogen is 300sccm.

[0020] The flow rate of acetylene in A3 is 50sccm.

[0021] Preferably, the preparation method of the modified titanium dioxide microspheres is as follows:

[0022] B1: Add nano-titanium dioxide in anhydrous ethanol and ultrasonic for 1-2h, then add octadecylamine and citric acid and stir at 80℃ for 6-12h, centrifugal separation, washing the precipitate, vacuum drying to obtain pretreated titanium dioxide;

[0023] B2: Add pretreated titanium dioxide in dicyclopentadiene and ultrasonic for 30-50min, then add toluene-2,4-diisocyanate, dibutyltin dilaurate, and tert-butyl benzoyl peroxide and stir for 10-15min to obtain a composite oil phase;

[0024] B3: Add deionized water in polyvinyl alcohol 1788 aqueous solution and stir at 45℃ for 20-30min, then add the composite oil phase and emulsify for 10-15min, and then ultrasonic treatment for 3-5min, then drop into ethylenediamine aqueous solution and stir for 6-7h, centrifugal, washing the precipitate, freeze-drying after cooling to obtain modified titanium dioxide microspheres.

[0025] Preferably, the mass ratio of the anhydrous ethanol, nano-titanium dioxide, octadecylamine, and citric acid in B1 is 200-220:5:2.5:0.1.

[0026] Preferably, the mass ratio of the dicyclopentadiene, pretreated titanium dioxide, toluene-2,4-diisocyanate, dibutyltin dilaurate, and tert-butyl benzoyl peroxide in B2 is 100:1.5:20:0.2:0.3-0.4.

[0027] Preferably, the mass ratio of the polyvinyl alcohol 1788 aqueous solution, deionized water, the complex oil phase, the ethylenediamine aqueous solution in B3 is 300:100:121.7:25-28;

[0028] The mass fraction of the polyvinyl alcohol 1788 aqueous solution in B3 is 2%;

[0029] The mass fraction of the ethylenediamine aqueous solution in B3 is 20%.

[0030] A preparation method of a lightweight heavy coating material for automobiles, comprising the following steps:

[0031] The polyvinyl chloride paste resin is added with mixed polyvinyl chloride resin, diisononyl phthalate 1 and dispersed at 800-1000 r / min for 8-10 min, then the adhesion promoter and viscosity reducer are added while stirring at 400-500 r / min for 3-5 min, then calcium oxide, modified silicon dioxide, zinc oxide, active nano calcium carbonate, heavy calcium, diisononyl phthalate 2 are added in sequence while stirring at 30-40 r / min for 45-50 min, then modified titanium dioxide microspheres are added and stirred for 10-15 min, then rolled and ground to a fineness of 15-25 mu m, finally, the automobile lightweight heavy coating material is obtained by vacuumizing, adding a foaming agent and circulating and dispersing at 600-800 r / min for 5-7 min in a reaction kettle, and vacuumizing and standing at 70-80 DEG C for 24-30 h.

[0032] The mass ratio of the diisononyl phthalate 1 and the diisononyl phthalate 2 is 14-16:8-10.

[0033] The beneficial effects of the present application are as follows:

[0034] The present application provides a lightweight heavy coating material for automobiles and a preparation method thereof, which effectively improves the impact resistance, stone chip resistance, weather resistance, high temperature resistance and corrosion resistance of the lightweight heavy coating material for automobiles.

[0035] (1) The porous hollow structure of the modified silica can adjust the coating density, can synergistically strengthen the lightweight effect with the foaming agent, and avoid the mechanical property loss of control due to simple foaming. The carbon nanotube and iron nanoparticle formed on the surface of the modified silica form a carbon-based composite structure with high rigidity, which can be used as a stress dispersion point, and when the coating is impacted, the local impact stress is conducted to the surrounding matrix to avoid crack initiation caused by stress concentration; the hollow cavity can absorb impact energy through deformation to buffer impact energy and reduce direct damage to the matrix; the interface bonding force between the carbon-based layer and the polyvinyl chloride matrix is strong, which can avoid defects caused by debonding of fillers and matrix during impact, and significantly improve the impact resistance of the coating. The rigid carbon-based composite structure can resist the cutting type impact of stone, reduce surface scratches or depressions; the hollow structure absorbs the kinetic energy of sandstone impact, reduces the penetration type damage to the inside of the coating. The rigid structure of the modified silica can inhibit the thermal oxidative aging shrinkage of the coating under ultraviolet light, reduce the cracking caused by the deformation of the matrix; the hollow structure reduces the thermal conductivity coefficient of the coating, weakens the synergistic aging effect of high temperature and ultraviolet light, and prolongs the weather resistance. The high temperature resistance of the siloxane skeleton and the carbon-based layer can reduce the heat transfer to the polyvinyl chloride matrix, and the rigid structure can resist the softening deformation under high temperature, and improve the thermal deformation temperature of the coating. The chemical stability of the siloxane skeleton and the carbon-based layer can block the penetration of corrosive media, the micron-sized particle fills the pores of the coating, reduces the diffusion path of the corrosive medium, and improves the corrosion resistance of the coating.

[0036] (2) The pure nano-titanium dioxide in the modified titanium dioxide microspheres has hard and brittle characteristics, and direct addition of the pure nano-titanium dioxide easily leads to increased rigidity and decreased toughness of the coating, but the polyurethane segment in the tough shell layer of the modified titanium dioxide microspheres has elasticity, can deform and absorb energy when impacted, buffer impact stress, and the polydicyclopentadiene has rigidity and toughness, can assist in dispersing stress and avoiding excessive deformation of the shell layer, and cooperatively improve the impact resistance of the coating. The tough shell layer of the modified titanium dioxide microspheres can directly buffer the kinetic energy of sandstone impact, reduce surface cutting scratches, and reduce the risk of coating exposure; the micron-sized particle size can fill the small pores in the coating, making the coating structure more dense and reducing peeling caused by sandstone penetration impact. The nano-titanium dioxide core material of the modified titanium dioxide microspheres can efficiently absorb ultraviolet light, convert light energy into heat energy for slow release, and avoid direct damage to the molecular chains of the polyvinyl chloride matrix by ultraviolet light; the polyurethane-polydicyclopentadiene interpenetrating network of the shell layer can stably fix the nano-titanium dioxide, avoid agglomeration to form a blind area of weather resistance, reduce oxidation failure caused by direct exposure of the nano-titanium dioxide, prolong the weather resistance time, and significantly improve the weather resistance of the coating. The nano-titanium dioxide core material of the modified titanium dioxide microspheres has a high melting point, which can assist in inhibiting the high-temperature softening of the polyvinyl chloride matrix; the interpenetrating network of the shell layer can still maintain toughness at high temperatures, avoid mechanical property decline of the coating caused by high-temperature embrittlement, and improve the high-temperature resistance of the material. The modified titanium dioxide microspheres can fill the small gaps between the resin and the filler, reduce the penetration channels of corrosive media such as water, salt mist, and acid rain; the nano-titanium dioxide core material has stable chemical properties, and in combination with the physical barrier effect of the shell layer, further blocks the contact of corrosive media with the metal substrate, and improves the corrosion resistance.

[0037] Of course, implementing any product of the present application does not necessarily require achieving all the advantages described above at the same time. DETAILED DESCRIPTION

[0038] The technical solutions in the embodiments of the present application will be clearly and completely described below in combination with the embodiments of the present application. The embodiments described below are only some of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0039] Unless otherwise specified, the following information of some raw materials used in the following examples and comparative examples of the present application is as follows:

[0040] Polyvinyl chloride paste resin was purchased from Shanghai Chlor-Alkali Chemical Co., Ltd., brand: P450; blended polyvinyl chloride resin was purchased from Shanghai Chlor-Alkali Chemical Co., Ltd., brand: SB100; polyvinyl alcohol 1788 was purchased from Hubei Yongkong Technology Co., Ltd., part number: YK2833; polyacrylic acid was purchased from Hubei Junrui Biological Technology Co., Ltd., part number: JR1196; adhesion promoter was purchased from Wuxi Shengyi Synthetic Material Co., Ltd., brand: SY-533; viscosity reducer was purchased from Jingmen Petrochemical, brand: D80; foaming agent was purchased from Beijing Sanchangtaihe Science and Technology Co., Ltd., brand: F-78D.

[0041] Example 1: A method for preparing a lightweight re-coating material for automobiles is as follows:

[0042] S1: 100 g of a 10% by mass polyacrylic acid aqueous solution was added to 200 g of deionized water and stirred at 300 r / min for 30 min, and then 10% by mass hydrochloric acid was used to adjust the pH to 2.5, after which the temperature was raised to 60°C and 0.5 g of N,N'-methylenebisacrylamide and 0.1 g of ammonium persulfate were added, and after stirring for 30 min, 28% by mass ammonia water was used to adjust the pH to 9.0 and stirred for 8 min, after which 2 g of cetyltrimethylammonium bromide was added and stirred for 30 min, then 20 g of tetraethyl orthosilicate was added dropwise at 1 mL / min at 60°C and stirred for 12 h, after which the temperature was lowered to 25°C and stirred for 4 h, then centrifuged and the precipitate was washed with deionized water 5 times, after which it was vacuum freeze-dried at -50°C and 10 Pa for 24 h, then the temperature was raised to 550°C at 2°C / min and calcined at 550°C in an air atmosphere for 5 h, after which it was cooled to obtain porous hollow silica microspheres;

[0043] S2: 2 g of the porous hollow silica microspheres were dispersed in 100 g of ethanol, after which 0.4 g of 3-aminopropyltriethoxysilane was added and refluxed at 60°C for 3 h, then centrifuged and the precipitate was washed with anhydrous ethanol 3 times, and vacuum dried at 55°C for 12 h to obtain aminosilica;

[0044] S3: 2 g of aminosilica was laid in a quartz boat and placed in the constant temperature zone of a tube furnace, first heated to 450℃ at a rate of 10℃ / min under nitrogen atmosphere and kept for 30 min, then kept for 30 min under the atmosphere of mixed gas of 200 sccm hydrogen and 300 sccm nitrogen, then heated to 650℃ at a rate of 10℃ / min and at the same time, 20 mL of ferrocene solution in xylene with a concentration of 0.05 g / mL was injected at a rate of 0.5 mL / min into the vaporization zone at the front end of the quartz tube at 220℃, 50 sccm of acetylene was introduced and kept for 30 min, then the acetylene and the injection pump were turned off, the temperature was lowered to 100℃ at a rate of 5℃ / min under the atmosphere of mixed gas of 200 sccm hydrogen and 300 sccm nitrogen, and finally the atmosphere was switched to pure nitrogen and cooled to 30℃, to obtain modified silica;

[0045] S4: 5 g of nano-titanium dioxide was added to 200 g of anhydrous ethanol and ultrasonically dispersed for 1 h, then 2.5 g of octadecylamine, 0.1 g of citric acid were added and stirred under reflux at 80℃ for 6 h, the precipitate was separated by centrifugation and washed with anhydrous ethanol 3 times, and then vacuum dried at 80℃ for 12 h to obtain pretreated titanium dioxide;

[0046] S5: 1.5 g of pretreated titanium dioxide was added to 100 g of dicyclopentadiene and ultrasonically treated for 30 min, then 20 g of toluene-2,4-diisocyanate, 0.2 g of dibutyltin dilaurate, 0.3 g of tert-butyl peroxybenzoate were added and stirred for 10 min to obtain a composite oil phase;

[0047] S6: 100 g of deionized water was added to 300 g of a 2% by mass polyvinyl alcohol 1788 aqueous solution and stirred at 400 r / min at 45℃ for 20 min, then 121.7 g of the composite oil phase was added and emulsified at 1000 r / min for 10 min, then ultrasonically treated for 3 min, then 25 g of a 20% by mass ethylenediamine aqueous solution was added dropwise at a rate of 1.2 mL / min and stirred at 400 r / min at 45℃ for 6 h, after cooling, the precipitate was separated by centrifugation and washed with deionized water 3 times, and finally vacuum freeze-dried at -50℃ and 10 Pa for 24 h to obtain modified titanium dioxide microspheres;

[0048] S7: 3 g of blended polyvinyl chloride resin, 14 g of diisononyl phthalate were added to 27 g of polyvinyl chloride paste resin and dispersed at 800 r / min for 8 min, then 1.5 g of adhesion promoter, 3 g of viscosity reducer were added while stirring at 400 r / min for 3 min, then 5 g of calcium oxide, 3 g of modified silicon dioxide, 2 g of zinc oxide, 17 g of active nano calcium carbonate, 5 g of heavy calcium, 8 g of diisononyl phthalate were added in turn while stirring at 30 r / min for 45 min, then 1.5 g of modified titanium dioxide microspheres were added and stirred for 10 min, then rolled and ground to a fineness of 15 μm, finally moved into a reaction kettle, vacuumized, added 0.8 g of foaming agent and circulated and dispersed at 600 r / min for 5 min, vacuumized and statically placed at 70℃ for 24 h to obtain a lightweight recoating material for automobiles.

[0049] Example 2: A preparation method of a lightweight recoating material for automobiles is as follows:

[0050] S1: 100 g of a 10% by mass polyacrylic acid aqueous solution was added to 225 g of deionized water and stirred at 300 r / min for 40 min, then the pH was adjusted to 2.8 with 10% by mass hydrochloric acid, heated to 60℃ and 0.5 g of N,N'-methylenebisacrylamide and 0.1 g of ammonium persulfate were added, stirred for 35 min, then the pH was adjusted to 9 with 28% ammonia water and stirred for 9 min, then 2 g of cetyltrimethylammonium bromide was added and stirred for 35 min, then 20 g of tetraethyl orthosilicate was added dropwise at 1 mL / min at 60℃ and stirred for 13 h, then after cooling to 28℃, stirring was continued for 4.5 h, then the precipitate was centrifuged and washed with deionized water 6 times, vacuum freeze-dried at -50℃ and 10 Pa for 25 h, then heated to 550℃ at 2℃ / min and calcined at 550℃ in an air atmosphere for 5.5 h, then cooled to obtain porous hollow silica microspheres;

[0051] S2: 2 g of porous hollow silica microspheres were dispersed in 110 g of ethanol, then 0.6 g of 3-aminopropyltriethoxysilane was added and refluxed at 60℃ for 3.5 h, then centrifuged and washed with anhydrous ethanol 4 times, vacuum dried at 55℃ for 13.5 h to obtain aminated silica;

[0052] S3: 2 g of aminosilica was laid in a quartz boat and placed in the constant temperature zone of a tube furnace, first heated to 450℃ at a rate of 10℃ / min under nitrogen atmosphere and kept for 35 min, then kept for 35 min under the atmosphere of mixed gas of 200 sccm hydrogen and 300 sccm nitrogen, then heated to 680℃ at a rate of 10℃ / min and at the same time, 25 mL of ferrocene solution in xylene with a concentration of 0.05 g / mL was injected at a rate of 0.5 mL / min into the vaporization zone at the front end of the quartz tube at 220℃, and 50 sccm of acetylene was passed in, and kept for 35 min, then the acetylene and the injection pump were turned off, and the temperature was lowered to 150℃ at a rate of 5℃ / min under the atmosphere of mixed gas of 200 sccm hydrogen and 300 sccm nitrogen, and finally cooled to 35℃ under pure nitrogen atmosphere, to obtain modified silica;

[0053] S4: 5 g of nano-titanium dioxide was added to 210 g of anhydrous ethanol and ultrasonically dispersed for 1.5 h, then 2.5 g of octadecylamine, 0.1 g of citric acid were added, and stirred under reflux at 80℃ for 9 h, the precipitate was separated by centrifugation and washed with anhydrous ethanol 4 times, and then vacuum dried at 80℃ for 14 h, to obtain pretreated titanium dioxide;

[0054] S5: 1.5 g of pretreated titanium dioxide was added to 100 g of dicyclopentadiene and ultrasonically treated for 40 min, then 20 g of toluene-2,4-diisocyanate, 0.2 g of dibutyltin dilaurate, 0.35 g of tert-butyl peroxybenzoate were added and stirred for 13 min, to obtain a composite oil phase;

[0055] S6: 100 g of deionized water was added to 300 g of a 2% by mass polyvinyl alcohol 1788 aqueous solution and stirred at 400 r / min at 45℃ for 25 min, then 121.7 g of the composite oil phase was added and emulsified at 1300 r / min for 13 min, and then ultrasonically treated for 4 min, then 26.5 g of a 20% by mass ethylenediamine aqueous solution was added dropwise at a rate of 1.2 mL / min and stirred at 400 r / min at 45℃ for 6.5 h, after cooling, the precipitate was separated by centrifugation and washed with deionized water 4 times, and finally vacuum freeze-dried at -50℃ and 10 Pa for 25 h, to obtain modified titanium dioxide microspheres;

[0056] S7: 3.3 g of blended polyvinyl chloride resin, 15 g of diisononyl phthalate were added to 28 g of polyvinyl chloride paste resin and dispersed at 900 r / min for 9 min, then 1.6 g of adhesion promoter, 3.3 g of viscosity reducer were added while stirring at 450 r / min for 4 min, then 5.3 g of calcium oxide, 3.2 g of modified silicon dioxide, 2.3 g of zinc oxide, 20 g of active nano calcium carbonate, 5.5 g of heavy calcium, 9 g of diisononyl phthalate were added in turn while stirring at 35 r / min for 48 min, then 1.8 g of modified titanium dioxide microspheres were added and stirred for 13 min, then rolled and ground to a fineness of 20 μm, finally moved into a reaction kettle, vacuumized, 0.9 g of foaming agent was added and circulated and dispersed at 700 r / min for 6 min, vacuumized and statically placed at 75℃ for 27 h to obtain a lightweight recoating material for automobiles.

[0057] Example 3: A preparation method of a lightweight recoating material for automobiles is as follows:

[0058] S1: 100 g of a polyacrylic acid aqueous solution with a mass fraction of 10% was added to 250 g of deionized water and stirred at 300 r / min for 50 min, then the pH was adjusted to 3 with 10% hydrochloric acid, heated to 60℃, and 0.5 g of N,N'-methylenebisacrylamide and 0.1 g of ammonium persulfate were added, stirred for 40 min, then the pH was adjusted to 9 with 28% ammonia water and stirred for 10 min, then 2 g of cetyltrimethylammonium bromide was added and stirred for 40 min, then 20 g of tetraethyl orthosilicate was added dropwise at 1 mL / min at 60℃ and stirred for 14 h, then cooled to 30℃ and stirred for 5 h, then centrifuged and the precipitate was washed with deionized water 7 times, vacuum freeze-dried at -50℃ and 10 Pa for 26 h, then heated to 550℃ at 2℃ / min and calcined at 550℃ in an air atmosphere for 6 h, and then cooled to obtain porous hollow silica microspheres;

[0059] S2: 2 g of porous hollow silica microspheres were dispersed in 120 g of ethanol, then 0.8 g of 3-aminopropyltriethoxysilane was added and refluxed at 60℃ for 4 h, then centrifuged and the precipitate was washed with anhydrous ethanol 5 times, and vacuum dried at 55℃ for 15 h to obtain aminated silica;

[0060] S3: 2 g of aminosilica was laid in a quartz boat and placed in the constant temperature zone of a tube furnace, first heated to 450℃ at a rate of 10℃ / min under nitrogen atmosphere and kept for 40 min, then kept for 40 min under the atmosphere of mixed gas of 200 sccm hydrogen and 300 sccm nitrogen, then heated to 700℃ at a rate of 10℃ / min and at the same time, 30 mL of ferrocene solution in xylene with a concentration of 0.05 g / mL was injected at a rate of 0.5 mL / min into the vaporization zone at the front end of the quartz tube at 220℃, and 50 sccm of acetylene was passed in, and kept for 40 min, then the acetylene and the injection pump were turned off, and the temperature was lowered to 200℃ at a rate of 5℃ / min under the atmosphere of mixed gas of 200 sccm hydrogen and 300 sccm nitrogen, and finally cooled to 40℃ under pure nitrogen atmosphere, to obtain modified silica;

[0061] S4: 5 g of nano-titanium dioxide was added to 220 g of anhydrous ethanol and ultrasonically dispersed for 2 h, then 2.5 g of octadecylamine, 0.1 g of citric acid were added, and stirred under reflux at 80℃ for 12 h, centrifuged and the precipitate was washed with anhydrous ethanol 5 times, then vacuum dried at 80℃ for 15 h, to obtain pretreated titanium dioxide;

[0062] S5: 1.5 g of pretreated titanium dioxide was added to 100 g of dicyclopentadiene and ultrasonically treated for 50 min, then 20 g of toluene-2,4-diisocyanate, 0.2 g of dibutyltin dilaurate, 0.4 g of tert-butyl peroxybenzoate were added and stirred for 15 min, to obtain a composite oil phase;

[0063] S6: 100 g of deionized water was added to 300 g of a 2% by mass polyvinyl alcohol 1788 aqueous solution and stirred at 400 r / min at 45℃ for 30 min, then 121.7 g of the composite oil phase was added and emulsified at 1500 r / min for 15 min, then ultrasonically treated for 5 min, then 28 g of a 20% by mass ethylenediamine aqueous solution was added dropwise at a rate of 1.2 mL / min and stirred at 400 r / min at 45℃ for 7 h, after cooling, centrifuged and the precipitate was washed with deionized water 5 times, and finally vacuum freeze-dried at -50℃ and 10 Pa for 26 h, to obtain modified titanium dioxide microspheres;

[0064] S7: 3.5 g of blended polyvinyl chloride resin, 16 g of diisononyl phthalate were added to 29 g of polyvinyl chloride paste resin and dispersed at 1000 r / min for 10 min, then 1.7 g of adhesion promoter, 3.5 g of viscosity reducer were added while stirring at 500 r / min for 5 min, then 5.5 g of calcium oxide, 3.5 g of modified silicon dioxide, 2.5 g of zinc oxide, 22 g of active nano calcium carbonate, 6 g of heavy calcium, 10 g of diisononyl phthalate were added in turn while stirring at 40 r / min for 50 min, then 2 g of modified titanium dioxide microspheres were added and stirred for 15 min, and then rolled and ground to a fineness of 25 μm, finally moved into a reaction kettle, vacuumized, added with 1 g of foaming agent and circulated and dispersed at 800 r / min for 7 min, and then vacuumized and statically placed at 80℃ for 30 h to obtain a lightweight recoating material for automobiles.

[0065] Comparative Example 1:

[0066] This comparative example only replaces the "modified silicon dioxide" added in the preparation process of S7 with the "aminated silicon dioxide" prepared in S2 compared with Example 1, and the rest of the steps and parameters are the same, this comparative example will not be repeated, finally a lightweight recoating material for automobiles is obtained.

[0067] Comparative Example 2:

[0068] This comparative example only does not add "modified silicon dioxide" in the preparation process of S7 compared with Example 1, and the rest of the steps and parameters are the same, this comparative example will not be repeated, finally a lightweight recoating material for automobiles is obtained.

[0069] Comparative Example 3:

[0070] This comparative example only replaces the "modified titanium dioxide microspheres" added in the preparation process of S7 with the "pretreated titanium dioxide" prepared in S4 compared with Example 1, and the rest of the steps and parameters are the same, this comparative example will not be repeated, finally a lightweight recoating material for automobiles is obtained.

[0071] Comparative Example 4:

[0072] This comparative example only does not add "modified titanium dioxide microspheres" in the preparation process of S7 compared with Example 1, and the rest of the steps and parameters are the same, this comparative example will not be repeated, finally a lightweight recoating material for automobiles is obtained.

[0073] Performance detection:

[0074] Spray the lightweight recoating material for automobile (nozzle diameter 1.5 mm, spray pressure 0.3 MPa) on a 150x70 mmx0.3 mm tin plate which is sanded (400 mesh) and clean and dry, spray twice (pre-bake at 60℃ for 30 min after the first spray, then spray the second time), the thickness of each spray is 40 μm, and the total dry film thickness of the test sample plate is 80 μm.

[0075] Determination of impact resistance:

[0076] According to the GB / T 1732-2020 "Determination of Impact Resistance of Paint Film" standard, the impact strength (kJ / m 2 ) of the surface coating of the test sample plate prepared from the lightweight recoating material for automobile prepared by the present application examples 1-3 and comparative examples 1-4 was determined with a 1 kg weight hammer 1 m high from the test sample plate, and the test results are shown in Table 1.

[0077] Determination of stone chip resistance:

[0078] The test plate was clamped directly on the test plate clamp, 1000 g of pebbles (diameter 9.5-16.5 mm) were loaded in the hopper of the stone chip resistance tester, the air pressure was adjusted to 0.5 MPa, then the air valve was opened, after all the pebbles were shot, the pebbles were reloaded, the impact was repeated for 25 times, and the air valve was closed; the test plate was taken out, the entire stone impact surface was taped with adhesive tape, then the adhesive tape was quickly torn off by hand, and the surface coating of the test plate was observed for peeling or cracking; the stone chip resistance of the surface coating of the test sample plate prepared from the lightweight recoating material for automobile prepared by the present application examples 1-3 and comparative examples 1-4 was determined according to the above method, and the test results are shown in Table 1.

[0079] Determination of weather resistance:

[0080] According to the GB / T 1766-2008 "Paint and Varnish - Method of Evaluating Coating Weathering" standard, the color difference ΔE of the coating of the test sample plate prepared from the lightweight recoating material for automobile prepared by the present application examples 1-3 and comparative examples 1-4 before and after 1000 h of cyclic ultraviolet aging under 0.76 W / m 2 , 340 nm was determined to reflect the weather resistance of the coating, and the test results are shown in Table 1.

[0081] Determination of high temperature resistance:

[0082] The heat distortion temperature (℃) of the coating of the test sample prepared from the lightweight recoating material for automobiles prepared by the application examples 1-3 and the comparative examples 1-4 under the load of 1.8 MPa was determined according to the GB / T 1634.2-2019 “Determination of the heat distortion temperature of plastics Part 2: Plastics and ebonite”, and the test results are shown in Table 1.

[0083] Determination of corrosion resistance:

[0084] According to the GB / T 10125-2021 “Salt spray test for artificial atmosphere corrosion test”, the test sample was edge sealed with epoxy putty, and then placed in a salt spray test box, 24 h salt spray and 24 h air drying cycle test were carried out at 35℃ with pH=7, 5% sodium chloride solution, and the test sample was observed every 48 h, and the test time of pitting and blistering on the surface of each test sample was recorded. The neutral salt spray test ended when the last sample appeared pitting and blistering. The corrosion resistance (h) of the surface coating of the test sample prepared from the lightweight recoating material for automobiles prepared by the application examples 1-3 and the comparative examples 1-4 was determined according to the above method, and the test results are shown in Table 1.

[0085] Table 1: Performance test results of examples 1-3 and comparative examples 1-4

[0086]

[0087] Data analysis:

[0088] As can be seen from Table 1, the lightweight recoating material for automobiles prepared by the application examples has excellent impact resistance, stone chip resistance, weather resistance, high temperature resistance and corrosion resistance.

[0089] In the description of the present specification, the description of the terms “one embodiment”, “example”, “specific example” and the like means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0090] The basic principles, main features and advantages of the present application are shown and described above. It should be understood by those skilled in the art that the present application is not limited by the above examples, and the above examples and descriptions in the specification are only to illustrate the principles of the present application. Without departing from the spirit and scope of the present application, various changes and improvements can be made to the present application, and these changes and improvements all fall within the scope of the claimed present application.

Claims

1. A lightweight re-coat material for automobiles, characterized by comprising a base material and a coating layer, wherein the base material is a metal sheet, and the coating layer is a resin layer. The raw materials include the following quality parts: polyvinyl chloride paste resin 27-29 parts, blended polyvinyl chloride resin 3-3.5 parts, diisononyl phthalate 22-26 parts, adhesion promoter 1.5-1.7 parts, viscosity reducer 3-3.5 parts, calcium oxide 5-5.5 parts, modified silicon dioxide 3-3.5 parts, zinc oxide 2-2.5 parts, active nano calcium carbonate 17-22 parts, heavy calcium 5-6 parts, modified titanium dioxide microspheres 1.5-2 parts, foaming agent 0.8-1 part; The modified silicon dioxide is porous hollow silica microspheres which are first grafted with 3-aminopropyltriethoxysilane to form an amino transition layer, and then are treated with ferrocene xylene solution as Fe source and acetylene gas as carbon source under a hydrogen-nitrogen-acetylene mixed atmosphere at 650-700 DEG C to form a uniform Fe-C layer by Fe catalytic carbon growth; the porous hollow silica microspheres are prepared by using polyacrylic acid-N,N'-methylene bisacrylamide gel as a primary template and cetyltrimethylammonium bromide as a secondary template, and then are hydrolyzed and condensed with tetraethyl orthosilicate and calcined at 550 DEG C in an air atmosphere; The modified titanium dioxide microspheres are prepared from dicyclopentadiene, pretreated titanium dioxide, toluene-2,4-diisocyanate, dibutyltin dilaurate, tert-butyl benzoyl peroxide, polyvinyl alcohol 1788, deionized water and ethylenediamine; the pretreated titanium dioxide is nano titanium dioxide grafted with octadecylamine; The preparation method of the modified silicon dioxide is as follows: A1: add polyacrylic acid aqueous solution in deionized water and stir well, adjust the pH to 2.5-3.0, then heat to 60 DEG C and add N,N'-methylene bisacrylamide and ammonium persulfate, stir for 30-40 min, then adjust the pH to 9, then add cetyltrimethylammonium bromide and stir for 30-40 min, then drop tetraethyl orthosilicate at 60 DEG C and stir for 12-14 h, stir for 4-5 h after cooling, centrifuge, wash the precipitate, freeze-dry, calcine at 550 DEG C in an air atmosphere for 5-6 h, and then cool to obtain porous hollow silica microspheres; A2: disperse the porous hollow silica microspheres in ethanol, then add 3-aminopropyltriethoxysilane and reflux at 60 DEG C for 3-4 h, centrifuge, wash the precipitate, vacuum dry to obtain aminated silicon dioxide; A3: place the aminated silicon dioxide in a quartz boat and place it in the constant temperature zone of a tube furnace, first heat to 450 DEG C in a nitrogen atmosphere and keep for 30-40 min, then keep for 30-40 min in a hydrogen-nitrogen mixed gas atmosphere, then heat to 650-700 DEG C and inject ferrocene xylene solution at the front end of the quartz tube, while injecting acetylene and keeping for 30-40 min, then turn off the acetylene and the injection pump and cool to 100-200 DEG C, finally cool in a pure nitrogen atmosphere to obtain modified silicon dioxide; The mass ratio of the deionized water, polyacrylic acid aqueous solution, N,N'-methylene bisacrylamide, ammonium persulfate, cetyltrimethylammonium bromide and tetraethyl orthosilicate in A1 is 200-250:100:0.5:0.1:2:

20. The mass fraction of the polyacrylic acid aqueous solution in A1 is 10%; The preparation method of the modified titanium dioxide microspheres is as follows: B1: nano-titanium dioxide is added in anhydrous ethanol and ultrasonated for 1-2 h, then octadecylamine and citric acid are added and stirred at 80℃ for 6-12 h, and then the pretreated titanium dioxide is obtained by centrifugal separation, washing, and vacuum drying; B2: the pretreated titanium dioxide is added in dicyclopentadiene and ultrasonated for 30-50 min, then toluene-2, 4-diisocyanate, dibutyltin dilaurate, and tert-butyl peroxybenzoate are added and stirred for 10-15 min to obtain a composite oil phase; B3: deionized water is added in a polyvinyl alcohol 1788 aqueous solution and stirred at 45℃ for 20-30 min, then the composite oil phase is added and emulsified for 10-15 min, and then ultrasonated for 3-5 min, and then an ethylenediamine aqueous solution is added and stirred for 6-7 h, and then centrifuged, washed, and freeze-dried to obtain the modified titanium dioxide microspheres.

2. The lightweight re-coating material for automobiles according to claim 1, characterized by, The mass ratio of the porous hollow silica microspheres, ethanol, and 3-aminopropyl triethoxysilane in A2 is 2:100-120:0.4-0.

8.

3. The lightweight re-coating material for automobiles according to claim 1, characterized by, The dosage ratio of the ferrocene xylene solution of the aminated silica dioxide and ferrocene in A3 is 2g:20-30mL; The concentration of the ferrocene xylene solution in A3 is 0.05g / mL; The flow rate of the acetylene in A3 is 50sccm.

4. The lightweight re-coating material for automobiles according to claim 1, characterized by, The mass ratio of the anhydrous ethanol, nano-titanium dioxide, octadecylamine, and citric acid in B1 is 200-220:5:2.5:0.

1.

5. The lightweight re-coating material for automobiles according to claim 1, wherein The mass ratio of the dicyclopentadiene, pretreated titanium dioxide, toluene-2, 4-diisocyanate, dibutyltin dilaurate, and tert-butyl peroxybenzoate in B2 is 100:1.5:20:0.2:0.3-0.

4.

6. The lightweight re-coating material for automobiles according to claim 1, wherein The mass ratio of the polyvinyl alcohol 1788 aqueous solution, deionized water, composite oil phase, and ethylenediamine aqueous solution in B3 is 300:100:121.7:25-28; The mass fraction of the polyvinyl alcohol 1788 aqueous solution in B3 is 2%; The mass fraction of the ethylenediamine aqueous solution in B3 is 20%.

7. A method for producing a lightweight re-coating material for automobiles according to any one of claims 1 to 6, characterized by, The method comprises the following steps: The polyvinyl chloride paste resin is added with the blended polyvinyl chloride resin, diisononyl phthalate 1, and dispersed for 8-10 min, then the adhesion promoter and viscosity reducer are added and stirred for 3-5 min, then the calcium oxide, modified silica, zinc oxide, active nano calcium carbonate, heavy calcium, diisononyl phthalate 2 are added and stirred for 45-50 min while stirring, then the modified titanium dioxide microspheres are added and stirred for 10-15 min, and then rolled and ground to a fineness of 15-25μm, and finally the light-weight recoating material for automobiles is obtained by vacuumizing in a reaction kettle, adding a foaming agent, and dispersing for 5-7 min, and then statically standing at 70-80℃ for 24-30 h. The mass ratio of the diisononyl phthalate 1 and diisononyl phthalate 2 is 14-16:8-10.

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