Pure aqueous high-impact high-temperature bicycle paint and preparation method thereof

Abstract

This invention relates to the field of coating technology, specifically to a pure water-based high-impact and high-temperature resistant bicycle paint and its preparation method. The pure water-based high-impact and high-temperature resistant bicycle paint comprises component A and component B. Component A includes the following components by weight: 100 parts of water-based epoxy resin emulsion; component B includes the following components by weight: 25-30 parts of water-based amine curing agent, 5.2-7.8 parts of starch nanocrystal modified reduced graphene oxide, 45-65 parts of ethylenediamine modified inorganic filler, 0.3-0.6 parts of silane coupling agent, 0-20 parts of pigment, 2-4 parts of additives, and 30-50 parts of deionized water. This invention, by combining raw materials such as starch nanocrystal modified graphene oxide, enables the bicycle paint to exhibit excellent impact resistance and high-temperature resistance.

Description

Technical Field

[0001] This invention relates to the field of coating technology, specifically to a pure water-based high-impact, high-temperature bicycle paint and its preparation method. Background Technology

[0002] Bicycle paint is a specialized coating used to protect the metal parts of bicycles and enhance their appearance. Modern bicycle paint needs to possess properties such as weather resistance, impact resistance, and rust prevention.

[0003] Traditional bicycle coatings mostly use solvent-based paints, which often contain harmful substances such as benzene and xylene, resulting in high VOC (volatile organic compound) emissions and significant harm to the environment and human health. Water-based paints, on the other hand, use water as a diluent, contain no harmful organic solvents or heavy metals, and have extremely low VOC content, meeting national environmental protection regulations. This significantly reduces pollution during production and use, leading to their increasingly widespread application in bicycle manufacturing.

[0004] Bicycles inevitably encounter bumps and collisions during riding. The paint needs to possess good impact resistance and adhesion to prevent cracking, peeling, or scratches caused by impacts. Furthermore, bicycles used outdoors are exposed to sunlight for extended periods, which can significantly raise the surface temperature of the paint, leading to cracking, stickiness, and reduced scratch resistance. Compared to solvent-based paints, water-based paints have certain limitations in impact resistance and high-temperature resistance; their high-temperature resistance and impact resistance are generally weaker. Therefore, research is needed on the formulation of water-based paints to obtain higher-performance versions that offer superior high-temperature and impact resistance when used as bicycle paint. Summary of the Invention

[0005] The purpose of this invention is to provide a pure water-based high-impact and high-temperature resistant bicycle paint and its preparation method. By combining starch nanocrystals with graphene oxide and other materials, the bicycle paint achieves excellent impact resistance and high-temperature resistance.

[0006] To achieve the above objectives, the present invention provides the following technical solution: A water-based, high-impact, high-temperature resistant bicycle paint, characterized in that the water-based, high-impact, high-temperature resistant bicycle paint comprises component A and component B, wherein the weight ratio of component A to component B is 1:1. Component A comprises the following components in parts by weight: 100 parts of waterborne epoxy resin emulsion; Component B comprises the following components in parts by weight: 25-30 parts of water-based amine curing agent, 5.2-7.8 parts of starch nanocrystal modified reduced graphene oxide, 45-65 parts of ethylenediamine modified inorganic filler, 0.3-0.6 parts of silane coupling agent, 0-20 parts of pigment, 2-4 parts of additives, and 30-50 parts of deionized water.

[0007] Preferably, the aqueous epoxy resin emulsion is a liquid bisphenol A epoxy resin emulsion, such as aqueous epoxy resin emulsion DER-WB3002.

[0008] Preferably, the preparation method of the starch nanocrystal modified reduced graphene oxide includes the following steps: (1) A graphene oxide ethanol / water mixed dispersion with a concentration of 1~3 mg / mL was prepared by using graphene oxide, deionized water and ethanol, and then spray-dried (using nitrogen as carrier gas) at a temperature of 150~160℃ to obtain graphene oxide with a wrinkled structure. (2) Nano-silica was loaded onto graphene oxide with a wrinkled structure, and nano-silica modified reduced graphene oxide was prepared. (3) The reduced graphene oxide modified with nano-silica is modified with starch nanocrystals to obtain the reduced graphene oxide modified with starch nanocrystals.

[0009] Preferably, in step (1), the preparation method of graphene oxide ethanol / water mixed dispersion includes the following steps: adding deionized water to graphene oxide to prepare an aqueous dispersion with a concentration of 10~30mg / mL, and then adding ethanol to prepare a graphene oxide ethanol / water mixed dispersion with a concentration of 1~3mg / mL.

[0010] The diameter of the graphene oxide is 0.5~3μm.

[0011] This invention prepares graphene oxide with a wrinkled structure by low-temperature spray drying. In the above preparation process, ethanol and water evaporate rapidly, causing the volume of the droplets to shrink, thereby giving the graphene oxide a certain wrinkled structure.

[0012] Preferably, step (2) specifically includes the following steps: Deionized water and acetic acid were added to anhydrous ethanol and stirred. Then, graphene oxide with a wrinkled structure was added and ultrasonically dispersed for 1-2 hours. Tetraethyl orthosilicate was added dropwise while ultrasonically dispersing. After the addition was completed, more was added and the mixture was stirred for 1-1.5 hours. The mixture was then filtered and dried in a constant temperature drying oven to constant weight. Then, under a nitrogen atmosphere, the temperature was raised to 550-600℃ and calcined for 2-3 hours. Finally, the mixture was cooled to room temperature with the furnace to obtain nano-silica modified reduced graphene oxide.

[0013] After calcination in a nitrogen atmosphere, graphene oxide is reduced to reduced graphene oxide, which is then firmly loaded with nano-silica on its surface, thus obtaining nano-silica-modified reduced graphene oxide.

[0014] Preferably, the mass ratio of tetraethyl orthosilicate, anhydrous ethanol, deionized water, and acetic acid is 1:15~20:4~5:0.15~0.25; and the mass ratio of tetraethyl orthosilicate to graphene oxide with a wrinkled structure is 1:1~1.2.

[0015] Preferably, step (3) specifically includes the following steps: Starch nanocrystals were added to an ethanol aqueous solution with a mass fraction of 60-70%, and the solution was heated to 40-50℃ and ultrasonically treated for 1-2 hours to obtain a starch nanocrystal dispersion with a concentration of 0.2-0.5 g / 100 mL. Then, nano-silica-modified reduced graphene oxide was added to the starch nanocrystal dispersion, and the solution was continuously shaken for 5-10 hours. After filtration and drying, the solution was kept at 150-160℃ for 3-4 hours and then cooled to obtain the starch nanocrystal-modified reduced graphene oxide.

[0016] In the above method, after continuous oscillation, a certain amount of starch nanocrystals are deposited and adsorbed on the surface of nano-silica modified reduced graphene oxide. After heat treatment at 150~160℃, the carbon hydroxyl groups of the starch nanocrystals can form chemical bonds with the silanol groups on the surface of nano-silica, thereby forming a stable surface modification of starch nanocrystals.

[0017] Preferably, the ethylenediamine-modified inorganic filler is one or a combination of two of the following: ethylenediamine-modified bentonite, ethylenediamine-modified mica powder, and ethylenediamine-modified talc powder. The preparation method of the ethylenediamine modified inorganic filler includes the following steps: The inorganic filler is mixed evenly in an aqueous solution of ethylenediamine with a mass fraction of 20-30%, then placed in a reaction vessel, the reaction vessel is sealed, and the temperature is raised to 70-90℃ and held for 5-10 hours. Then it is cooled to below 50℃, filtered and dried to obtain the ethylenediamine modified inorganic filler.

[0018] Preferably, the additives include dispersants, leveling agents, and defoamers; the mass ratio of the dispersant, leveling agent, and defoamer is 1:0.2~0.6:0.1~0.2.

[0019] The leveling agent is one or more of BYK-333 and BYK-381; the defoamer is one or more of BYK-028 and BYK-016; and the dispersant is one or more of BYK-190 and BYK-191.

[0020] In addition, the pigments used in this invention may specifically be iron oxide yellow, iron oxide red, titanium dioxide, etc.

[0021] As a general inventive concept, this invention provides a method for preparing a pure water-based, high-impact, high-temperature resistant bicycle paint, comprising the following steps: The water-based amine curing agent, starch nanocrystal modified reduced graphene oxide, ethylenediamine modified inorganic filler, silane coupling agent, and deionized water are mixed and stirred evenly. Then, the remaining raw materials in component B are added, stirred and mixed, and filtered to obtain component B. When using pure water-based high-impact, high-temperature bicycle paint, mix component A and component B evenly in a 1:1 ratio before use.

[0022] The technical effects of this invention are: This invention incorporates starch nanocrystal-modified reduced graphene oxide into a two-component waterborne epoxy resin bicycle paint. The main body of this starch nanocrystal-modified reduced graphene oxide is a reduced graphene oxide material with a wrinkled structure. The surface of this wrinkled reduced graphene oxide is loaded with nano-silica and further contains an appropriate amount of starch nanocrystals. By giving the reduced graphene oxide a wrinkled structure, its dispersibility in the epoxy resin paint film can be effectively improved. At the same time, the reduced graphene oxide with a wrinkled structure can form a three-dimensional network in the paint film. When the paint film is impacted, the wrinkled structure can effectively absorb and disperse energy, hindering the propagation path of cracks. Its bonding with epoxy resin is tighter, and it can enhance the bonding ability with the epoxy resin paint film, reducing the risk of peeling of the bicycle paint film under impact. Graphene materials modified with starch nanocrystals, which are hydrophilic, enhance the compatibility of graphene with water-based epoxy resins and improve their interfacial adhesion. Furthermore, the steric hindrance effect of the starch nanocrystals further enhances the dispersibility of graphene, better demonstrating its reinforcing effect and improving the impact resistance and high-temperature resistance of the coating film. Additionally, the reduced graphene oxide-loaded nano-silica strengthens the connection stability of the starch nanocrystals on the graphene surface and enhances the intercalation strength of the graphene material within the coating film.

[0023] The inorganic filler in this invention is modified with ethylenediamine, which introduces organic amine chains onto the filler surface, increases the steric hindrance effect, further enhances the dispersibility of the inorganic filler in epoxy resin, improves the interfacial adhesion between the inorganic filler and epoxy resin, strengthens the compatibility between the inorganic filler and epoxy resin, and effectively enhances the impact resistance of bicycle paint, etc.

[0024] The pure water-based, high-impact, high-temperature resistant bicycle paint of this invention has high environmental performance. By combining it with starch nanocrystals modified with graphene oxide, the bicycle paint achieves excellent impact resistance and high-temperature resistance. Detailed Implementation

[0025] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0026] In this embodiment of the invention, the waterborne epoxy resin emulsion is DER-WB3002, purchased from Dow Chemical Company, USA; the waterborne amine curing agent is EPIKURE 6870-W-53, a waterborne epoxy amine curing agent from Hansen Chemical.

[0027] Example 1: A pure water-based, high-impact, high-temperature bicycle paint, comprising component A and component B, wherein the weight ratio of component A to component B is 1:1; Component A includes the following components in parts by weight: 100 parts of waterborne epoxy resin emulsion; Component B comprises the following components by weight: 27 parts water-based amine curing agent, 7 parts starch nanocrystal modified reduced graphene oxide, 58 parts ethylenediamine modified bentonite, 0.5 parts silane coupling agent KH560, 4 parts additives, and 45 parts deionized water. The additives consist of dispersant BYK-190, leveling agent BYK-333, and defoamer BYK-028 in a mass ratio of 1:0.2:0.1.

[0028] In this embodiment, the preparation method of starch nanocrystal modified reduced graphene oxide includes the following steps: (1) Add deionized water to graphene oxide (diameter 0.5~3μm) to prepare an aqueous dispersion with a concentration of 30mg / mL, then add ethanol to prepare a graphene oxide ethanol / water mixed dispersion with a concentration of 2mg / mL; then spray dry (using nitrogen as carrier gas) at a temperature of 150℃ to obtain graphene oxide with a wrinkled structure.

[0029] (2) Add deionized water and acetic acid to anhydrous ethanol, stir and mix, then add graphene oxide with a wrinkled structure, ultrasonically disperse for 2 hours, then add tetraethyl orthosilicate dropwise while ultrasonically dispersing, and after the dropwise addition is complete, add more and continue mixing and stirring for 1 hour, then filter, and place in a constant temperature drying oven at 60°C to dry to constant weight, then heat to 580°C under nitrogen atmosphere and calcine for 2 hours, and then cool to room temperature with the furnace to obtain nano-silica modified reduced graphene oxide; The mass ratio of tetraethyl orthosilicate, anhydrous ethanol, deionized water, and acetic acid is 1:18:5:0.2; the mass ratio of tetraethyl orthosilicate to graphene oxide with a wrinkled structure is 1:1.

[0030] (3) Add starch nanocrystals to a 70% ethanol aqueous solution, heat to 50℃ and sonicate for 2h to obtain a starch nanocrystal dispersion with a concentration of 0.4g / 100mL; then add nano-silica modified reduced graphene oxide to the starch nanocrystal dispersion, with a mass-volume ratio of nano-silica modified reduced graphene oxide to starch nanocrystal dispersion of 1g:50mL; continue shaking for 7h, then filter and dry, then keep warm at 150℃ for 4h, and after cooling, obtain starch nanocrystal modified reduced graphene oxide.

[0031] In this embodiment, the preparation method of ethylenediamine modified bentonite includes the following steps: Bentonite was mixed evenly in a 30% (w / w) ethylenediamine aqueous solution with a mass-volume ratio of 1 g: 25 mL. The mixture was then placed in a reaction vessel, which was sealed. The temperature was raised to 70°C and held for 10 h. The mixture was then cooled to below 50°C, filtered, and dried to obtain ethylenediamine-modified bentonite.

[0032] In this embodiment, the preparation method of pure water-based high-impact and high-temperature resistant bicycle paint includes the following steps: Aqueous amine curing agent, starch nanocrystal modified reduced graphene oxide, ethylenediamine modified bentonite, silane coupling agent KH560, and deionized water were mixed and stirred evenly. Then, the additives were added, and after stirring and mixing, the mixture was filtered to obtain component B. When using pure water-based high-impact, high-temperature bicycle paint, mix component A and component B evenly in a 1:1 ratio before use.

[0033] Example 2: A pure water-based, high-impact, high-temperature bicycle paint, comprising component A and component B, wherein the weight ratio of component A to component B is 1:1; Component A includes the following components in parts by weight: 100 parts of waterborne epoxy resin emulsion; Component B comprises the following components by weight: 30 parts of water-based amine curing agent, 5.2 parts of starch nanocrystal modified reduced graphene oxide, 65 parts of ethylenediamine modified bentonite, 0.6 parts of silane coupling agent KH560, 3 parts of additives, and 50 parts of deionized water. The additives consist of dispersant BYK-190, leveling agent BYK-333, and defoamer BYK-028 in a mass ratio of 1:0.5:0.2.

[0034] In this embodiment, the preparation method of starch nanocrystal modified reduced graphene oxide includes the following steps: (1) Add deionized water to graphene oxide (diameter 0.5~3μm) to prepare an aqueous dispersion with a concentration of 30mg / mL, then add ethanol to prepare a graphene oxide ethanol / water mixed dispersion with a concentration of 3mg / mL; then spray dry (using nitrogen as carrier gas) at a temperature of 150℃ to obtain graphene oxide with a wrinkled structure.

[0035] (2) Add deionized water and acetic acid to anhydrous ethanol, stir and mix, then add graphene oxide with a wrinkled structure, ultrasonically disperse for 1 h, then add tetraethyl orthosilicate dropwise while ultrasonically dispersing, after the dropwise addition is complete, add more and continue mixing and stirring for 1.5 h, then filter, and place in a constant temperature drying oven at 60℃ to dry to constant weight, then heat to 550℃ under nitrogen atmosphere and calcine for 3 h, then cool to room temperature with the furnace to obtain nano silica modified reduced graphene oxide; The mass ratio of tetraethyl orthosilicate, anhydrous ethanol, deionized water, and acetic acid is 1:15:4:0.15; the mass ratio of tetraethyl orthosilicate to graphene oxide with a wrinkled structure is 1:1.2.

[0036] (3) Add starch nanocrystals to a 60% ethanol aqueous solution, heat to 40℃ and sonicate for 1h to obtain a starch nanocrystal dispersion with a concentration of 0.2g / 100mL; then add nano-silica modified reduced graphene oxide to the starch nanocrystal dispersion, with a mass-volume ratio of nano-silica modified reduced graphene oxide to starch nanocrystal dispersion of 1g:50mL; continue shaking for 10h, then filter, dry, and then keep warm at 160℃ for 3h. After cooling, obtain starch nanocrystal modified reduced graphene oxide.

[0037] In this embodiment, the preparation method of ethylenediamine modified bentonite includes the following steps: Bentonite was mixed evenly in a 20% (w / w) ethylenediamine aqueous solution with a mass-volume ratio of 1 g: 25 mL. The mixture was then placed in a reaction vessel, which was sealed. The temperature was raised to 90°C and held for 5 hours. The mixture was then cooled to below 50°C, filtered, and dried to obtain ethylenediamine-modified bentonite.

[0038] In this embodiment, the preparation method of the pure water-based high-impact, high-temperature bicycle paint is the same as in Example 1.

[0039] Example 3: A pure water-based, high-impact, high-temperature bicycle paint, comprising component A and component B, wherein the weight ratio of component A to component B is 1:1; Component A includes the following components in parts by weight: 100 parts of waterborne epoxy resin emulsion; Component B comprises the following components by weight: 25 parts of water-based amine curing agent, 7.8 parts of starch nanocrystal modified reduced graphene oxide, 45 parts of ethylenediamine modified bentonite, 0.3 parts of silane coupling agent KH560, 2 parts of additives, and 30 parts of deionized water. The additives consist of dispersant BYK-190, leveling agent BYK-333, and defoamer BYK-028 in a mass ratio of 1:0.6:0.2.

[0040] In this embodiment, the preparation method of starch nanocrystal modified reduced graphene oxide includes the following steps: (1) Add deionized water to graphene oxide (diameter 0.5~3μm) to prepare an aqueous dispersion with a concentration of 10mg / mL, then add ethanol to prepare a graphene oxide ethanol / water mixed dispersion with a concentration of 1mg / mL; then spray dry (using nitrogen as carrier gas) at a temperature of 160℃ to obtain graphene oxide with a wrinkled structure.

[0041] (2) Add deionized water and acetic acid to anhydrous ethanol, stir and mix, then add graphene oxide with a wrinkled structure, ultrasonically disperse for 1.5 h, then add tetraethyl orthosilicate dropwise while ultrasonically dispersing, and after the dropwise addition is complete, add more and continue mixing and stirring for 1 h, then filter, and place in a constant temperature drying oven at 60℃ to dry to constant weight, then heat to 600℃ under nitrogen atmosphere and calcine for 2 h, and then cool to room temperature with the furnace to obtain nano silica modified reduced graphene oxide; The mass ratio of tetraethyl orthosilicate, anhydrous ethanol, deionized water, and acetic acid is 1:20:5:0.25; the mass ratio of tetraethyl orthosilicate to graphene oxide with a wrinkled structure is 1:1.

[0042] (3) Add starch nanocrystals to a 70% ethanol aqueous solution, heat to 50℃ and sonicate for 1.5h to obtain a starch nanocrystal dispersion with a concentration of 0.5g / 100mL; then add nano-silica modified reduced graphene oxide to the starch nanocrystal dispersion, with a mass-volume ratio of nano-silica modified reduced graphene oxide to starch nanocrystal dispersion of 1g:50mL; continue shaking for 5h, then filter and dry, then keep warm at 150℃ for 4h, and after cooling, obtain starch nanocrystal modified reduced graphene oxide.

[0043] The preparation method of ethylenediamine modified bentonite in this embodiment is the same as that in Example 1.

[0044] In this embodiment, the preparation method of the pure water-based high-impact, high-temperature bicycle paint is the same as in Example 1.

[0045] Example 4: A pure water-based, high-impact, high-temperature bicycle paint, comprising component A and component B, wherein the weight ratio of component A to component B is 1:1; Component A includes the following components in parts by weight: 100 parts of waterborne epoxy resin emulsion; Component B comprises the following components by weight: 26 parts of water-based amine curing agent, 6 parts of starch nanocrystal modified reduced graphene oxide, 50 parts of ethylenediamine modified bentonite, 0.5 parts of silane coupling agent KH560, 3 parts of additives, and 45 parts of deionized water. The additives consist of dispersant BYK-190, leveling agent BYK-333, and defoamer BYK-028 in a mass ratio of 1:0.3:0.15.

[0046] In this embodiment, the preparation methods of starch nanocrystal modified reduced graphene oxide and ethylenediamine modified bentonite are the same as in Example 1.

[0047] The preparation method of the pure water-based high-impact, high-temperature bicycle paint in this embodiment is the same as in Example 1.

[0048] Example 5: A pure water-based, high-impact, high-temperature bicycle paint, comprising component A and component B, wherein the weight ratio of component A to component B is 1:1; Component A includes the following components in parts by weight: 100 parts of waterborne epoxy resin emulsion; Component B comprises the following components by weight: 28 parts of water-based amine curing agent, 6.7 parts of starch nanocrystal modified reduced graphene oxide, 55 parts of ethylenediamine modified bentonite, 0.5 parts of silane coupling agent KH560, 2 parts of additives, and 35 parts of deionized water. The additives consist of dispersant BYK-190, leveling agent BYK-333, and defoamer BYK-028 in a mass ratio of 1:0.5:0.1.

[0049] In this embodiment, the preparation methods of starch nanocrystal modified reduced graphene oxide and ethylenediamine modified bentonite are the same as in Example 2.

[0050] The preparation method of the pure water-based high-impact, high-temperature bicycle paint in this embodiment is the same as in Example 1.

[0051] Comparative Example 1: Unlike Example 1, the preparation method of starch nanocrystal modified reduced graphene oxide includes the following steps: (1) Add deionized water and acetic acid to anhydrous ethanol, stir and mix, then add graphene oxide (0.5~3μm in diameter), ultrasonically disperse for 2h, then add tetraethyl orthosilicate dropwise while ultrasonically dispersing, and after the dropwise addition is complete, add more and continue mixing and stirring for 1h, then filter, and place in a constant temperature drying oven at 60℃ to dry to constant weight, then heat to 580℃ under nitrogen atmosphere and calcine for 2h, and then cool to room temperature with the furnace to obtain nano-silica modified reduced graphene oxide; The mass ratio of tetraethyl orthosilicate, anhydrous ethanol, deionized water, and acetic acid is 1:18:5:0.2; the mass ratio of tetraethyl orthosilicate to graphene oxide is 1:1.

[0052] (2) Add starch nanocrystals to a 70% ethanol aqueous solution and heat to 50℃ for 2 hours to obtain a starch nanocrystal dispersion with a concentration of 0.4g / 100mL. Then add nano-silica-modified reduced graphene oxide to the starch nanocrystal dispersion. The mass-volume ratio of nano-silica-modified reduced graphene oxide to starch nanocrystal dispersion is 1g:50mL. Continue shaking for 7 hours, then filter and dry. Then keep warm at 150℃ for 4 hours. After cooling, obtain starch nanocrystal-modified reduced graphene oxide.

[0053] Comparative Example 2: The difference from Example 1 is that the starch nanocrystal modified reduced graphene oxide is replaced with starch nanocrystal modified graphene oxide; The preparation method of starch nanocrystal modified graphene oxide includes the following steps: (1) Add deionized water to graphene oxide (diameter 0.5~3μm) to prepare an aqueous dispersion with a concentration of 30mg / mL, then add ethanol to prepare a graphene oxide ethanol / water mixed dispersion with a concentration of 2mg / mL; then spray dry at a temperature of 150℃ to obtain graphene oxide with a wrinkled structure.

[0054] (2) Add starch nanocrystals to a 70% ethanol aqueous solution, heat to 50℃ and sonicate for 2h to obtain a starch nanocrystal dispersion with a concentration of 0.4g / 100mL; then add graphene oxide with a wrinkled structure to the starch nanocrystal dispersion, with a mass-volume ratio of 1g:50mL of graphene oxide with a wrinkled structure to the starch nanocrystal dispersion; continue shaking for 7h, then filter, dry, and then keep warm at 150℃ for 4h. After cooling, obtain starch nanocrystal modified graphene oxide.

[0055] Comparative Example 3:

[0056] Unlike Example 1, starch nanocrystal modified reduced graphene oxide was replaced with nano-silica modified reduced graphene oxide; The preparation method of nano-silica modified reduced graphene oxide includes the following steps: (1) Add deionized water to graphene oxide (diameter 0.5~3μm) to prepare an aqueous dispersion with a concentration of 30mg / mL, then add ethanol to prepare a graphene oxide ethanol / water mixed dispersion with a concentration of 2mg / mL; then spray dry at a temperature of 150℃ to obtain graphene oxide with a wrinkled structure.

[0057] (2) Add deionized water and acetic acid to anhydrous ethanol, stir and mix, then add graphene oxide with a wrinkled structure, ultrasonically disperse for 2 hours, then add tetraethyl orthosilicate dropwise while ultrasonically dispersing, and after the dropwise addition is complete, add more and continue mixing and stirring for 1 hour, then filter, and place in a constant temperature drying oven at 60°C to dry to constant weight, then heat to 580°C under nitrogen atmosphere and calcine for 2 hours, and then cool to room temperature with the furnace to obtain nano-silica modified reduced graphene oxide; The mass ratio of tetraethyl orthosilicate, anhydrous ethanol, deionized water, and acetic acid is 1:18:5:0.2; the mass ratio of tetraethyl orthosilicate to graphene oxide with a wrinkled structure is 1:1.

[0058] Comparative Example 4: Unlike Example 1, starch nanocrystals modified reduced graphene oxide was replaced with graphene oxide (0.5~3 μm in diameter).

[0059] Comparative Example 5: Unlike Example 1, in preparing starch nanocrystal-modified reduced graphene oxide, step (3) includes the following steps: adding starch nanocrystals to a 70% ethanol aqueous solution, heating to 50°C and sonicating for 2 hours to obtain a starch nanocrystal dispersion with a concentration of 1 g / 100 mL; then adding nano-silica-modified reduced graphene oxide to the starch nanocrystal dispersion, with a mass-volume ratio of nano-silica-modified reduced graphene oxide to starch nanocrystal dispersion of 1 g: 50 mL; then continuing to shake for 7 hours, then filtering and drying, and then keeping warm at 150°C for 4 hours, and after cooling, obtaining starch nanocrystal-modified reduced graphene oxide.

[0060] Performance testing: For the bicycle paints in Examples 1-5 and Comparative Examples 1-5, the impact strength was tested according to the standard GB / T 1732-2020. A fixed-mass hammer (1kg) was dropped freely, and the maximum height (in centimeters) that did not cause damage to the paint film was measured to test the impact resistance of the paint film. The paint film was then placed in an environment of 250℃ for 15 days, and the changes in the appearance of the paint film were observed to test its high-temperature resistance.

[0061] In addition, adhesion testing (cross-cut test) was conducted in accordance with GB / T 9286; and neutral salt spray resistance testing was conducted in accordance with GB / T 1771-2007.

[0062] The specific test results are shown in Table 1.

[0063] Table 1: Example 1 130 No cracks or peeling in the paint film 0 3870 Example 2 125 No cracks or peeling in the paint film 0 3770 Example 3 130 No cracks or peeling in the paint film 0 3790 Example 4 125 No cracks or peeling in the paint film 0 3820 Example 5 130 No cracks or peeling in the paint film 0 3850 Comparative Example 1 100 The paint film has a few cracks but no peeling. 1 3180 Comparative Example 2 105 The paint film has a few cracks but no peeling. 1 3310 Comparative Example 3 110 The paint film has minor cracks but no peeling. 1 3450 Comparative Example 4 80 The paint film has a few cracks and slight peeling. 1 2780 Comparative Example 5 115 No cracks or peeling in the paint film 0 3570 As shown in Table 1, the bicycle paints in the examples all exhibit excellent impact resistance, high temperature resistance, as well as excellent adhesion and corrosion resistance.

[0064] As can be seen from the comparison between Example 1 and Comparative Examples 1 to 4, if graphene oxide is not modified by wrinkling, silica, or starch nanocrystals, all properties will be reduced. In particular, if completely unmodified graphene oxide is used as a graphene reinforcing material, all properties will be significantly reduced.

[0065] The comparison between Comparative Example 1 and Comparative Example 5 shows that if the concentration of the starch nanocrystal dispersion is too high, it will also have an adverse effect on the reinforcing properties of the obtained starch nanocrystal modified reduced graphene oxide.

[0066] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A pure aqueous high-scrubbing high-temperature bicycle paint, characterized by, The pure water-based high-impact and high-temperature resistant bicycle paint includes component A and component B, and the weight ratio of component A to component B is 1:

1. Component A comprises the following components in parts by weight: 100 parts of waterborne epoxy resin emulsion; Component B comprises the following components in parts by weight: 25-30 parts of water-based amine curing agent, 5.2-7.8 parts of starch nanocrystal modified reduced graphene oxide, 45-65 parts of ethylenediamine modified inorganic filler, 0.3-0.6 parts of silane coupling agent, 0-20 parts of pigment, 2-4 parts of additives, and 30-50 parts of deionized water; The preparation method of the starch nanocrystal modified reduced graphene oxide includes the following steps: (1) Add deionized water to graphene oxide to prepare an aqueous dispersion with a concentration of 10~30 mg / mL, then add ethanol to prepare a graphene oxide ethanol / water mixed dispersion with a concentration of 1~3 mg / mL; then spray dry at a temperature of 150~160℃ to obtain graphene oxide with a wrinkled structure. (2) Add deionized water and acetic acid to anhydrous ethanol, stir and mix, then add graphene oxide with a wrinkled structure, ultrasonically disperse for 1-2 hours, then add tetraethyl orthosilicate dropwise while ultrasonically dispersing, and after the dropwise addition is complete, add more and continue mixing and stirring for 1-1.5 hours, then filter, and place in a constant temperature drying oven to dry to constant weight, then heat to 550-600℃ under a nitrogen atmosphere and calcine for 2-3 hours, and then cool to room temperature with the furnace to obtain nano-silica modified reduced graphene oxide; (3) Add starch nanocrystals to an ethanol aqueous solution with a mass fraction of 60-70%, heat to 40-50℃ and sonicate for 1-2 hours to obtain a starch nanocrystal dispersion with a concentration of 0.2-0.5 g / 100 mL; then add nano-silica modified reduced graphene oxide to the starch nanocrystal dispersion, continue to shake for 5-10 hours, then filter and dry, and then keep warm at 150-160℃ for 3-4 hours. After cooling, obtain the starch nanocrystal modified reduced graphene oxide.

2. The pure aqueous high-scrubbing high-temperature bicycle paint according to claim 1, characterized by, The aqueous epoxy resin emulsion is a liquid bisphenol A epoxy resin emulsion.

3. The water-based, high-impact, high-temperature resistant bicycle paint according to claim 1, characterized in that, In step (1), the diameter of the graphene oxide is 0.5~3μm.

4. The water-based, high-impact, high-temperature resistant bicycle paint according to claim 1, characterized in that, In step (2), the mass ratio of tetraethyl orthosilicate, anhydrous ethanol, deionized water, and acetic acid is 1:15~20:4~5:0.15~0.25; the mass ratio of tetraethyl orthosilicate to graphene oxide with a wrinkled structure is 1:1~1.

2.

5. The water-based, high-impact, high-temperature resistant bicycle paint according to claim 1, characterized in that, The ethylenediamine-modified inorganic filler is one or a combination of two of the following: ethylenediamine-modified bentonite, ethylenediamine-modified mica powder, and ethylenediamine-modified talc powder. The preparation method of the ethylenediamine modified inorganic filler includes the following steps: The inorganic filler is mixed evenly in an aqueous solution of ethylenediamine with a mass fraction of 20-30%, then placed in a reaction vessel, the reaction vessel is sealed, and the temperature is raised to 70-90℃ and held for 5-10 hours. Then it is cooled to below 50℃, filtered and dried to obtain the ethylenediamine modified inorganic filler.

6. The water-based, high-impact, high-temperature resistant bicycle paint according to claim 1, characterized in that, The additives include dispersants, leveling agents, and defoamers; the mass ratio of the dispersants, leveling agents, and defoamers is 1:0.2~0.6:0.1~0.

2.

7. A method for preparing a pure water-based high-impact, high-temperature bicycle paint according to any one of claims 1 to 6, characterized in that, Includes the following steps: The water-based amine curing agent, starch nanocrystal modified reduced graphene oxide, ethylenediamine modified inorganic filler, silane coupling agent, and deionized water are mixed and stirred evenly. Then, the remaining raw materials in component B are added, stirred and mixed, and filtered to obtain component B. When using pure water-based high-impact, high-temperature bicycle paint, mix component A and component B evenly in a 1:1 ratio before use.