Aqueous teflon coating and method of making same

Abstract

The application provides a kind of water-based Teflon coating and its preparation method, belongs to the field of coating technology.P doped graphene quantum dots are deposited on Teflon microparticles, embedded in SiO2 shell, and after surface modification by polydopamine, reacted with acrylic acid, then polymerized to obtain modified polyacrylic acid resin emulsion, stirred and mixed uniformly with UiO-66@boron nitride particles, water, defoaming agent, dispersant, leveling agent, cosolvent, to obtain water-based Teflon coating.The water-based Teflon coating prepared by the application overcomes the shortcomings of traditional Teflon coating, such as easy agglomeration of polytetrafluoroethylene in water-based system, poor adhesion, insufficient hardness, poor wear resistance, poor heat dissipation, etc.The prepared water-based Teflon has good mechanical properties, wear resistance and appropriate hardness, good adhesion, good heat dissipation and thermal conductivity, good water dispersibility, easy storage and transportation, and the weather resistance of Teflon coating, with broad application prospects.

Description

Technical Field

[0001] This invention relates to the field of coating technology, specifically to a water-based Teflon coating and its preparation method. Background Technology

[0002] Organic fluorine coatings are a type of coating made by using fluoropolymers as film-forming substances and adding various pigments, fillers, and additives. They are divided into three types: powder coatings, water-based coatings, and organic solvent-dispersed coatings. Fluoropolymers possess excellent chemical and solvent resistance; superior weather resistance, stain resistance, water and oil resistance; and an extremely low coefficient of friction. They are widely used in heavy-duty anti-corrosion coatings (acid and alkali resistant, chemical resistant, and temperature resistant), ultra-weather resistant architectural coatings, anti-corrosion coatings, friction-reducing, and self-lubricating coatings. Polytetrafluoroethylene (PTFE) is the most widely used and highest-performing fluoropolymer, known as the "King of Plastics." Besides sintering, PTFE can also be used to make coatings. Currently, most Teflon coatings are water-based and generally require a two-step process: a primer followed by a coat. It has strict requirements for substrate treatment, is relatively troublesome to apply, has limited spray thickness, is prone to peeling, has high porosity, slightly poor adhesion, insufficient hardness, and poor heat dissipation. In addition, polytetrafluoroethylene particles are prone to agglomeration in water-based systems, and traditional dispersants (such as fluorinated surfactants) may introduce environmental risks. Summary of the Invention

[0003] The purpose of this invention is to propose a water-based Teflon coating and its preparation method, which overcomes the shortcomings of traditional Teflon coatings, such as easy agglomeration of polytetrafluoroethylene in water-based systems, poor adhesion, insufficient hardness, poor wear resistance, and poor heat dissipation. The resulting water-based Teflon coating has excellent mechanical properties, wear resistance, and suitable hardness, as well as good adhesion. At the same time, it has good heat dissipation and thermal conductivity, good water dispersibility, and is easy to store and transport. It also has the weather resistance characteristics of Teflon coatings and has broad application prospects.

[0004] The technical solution of this invention is implemented as follows:

[0005] This invention provides a method for preparing a water-based Teflon coating. P-doped graphene quantum dots are deposited onto Teflon microparticles, which are then embedded in a SiO2 shell. After surface modification with polydopamine, the microparticles react with acrylic acid and polymerize to obtain a modified polyacrylic acid resin emulsion. This emulsion is then mixed uniformly with UiO-66@boron nitride particles, water, defoamer, dispersant, leveling agent, and cosolvent to obtain the water-based Teflon coating.

[0006] As a further improvement to the present invention, the following steps are included:

[0007] S1. Preparation of P-doped graphene quantum dots: Citric acid and phytic acid were mixed and dissolved in water, heated to react, dialyzed, and the impurity was freeze-dried to obtain P-doped graphene quantum dots;

[0008] S2. Preparation of graphene quantum dot deposited Teflon microparticles: Teflon micro powder was ball-milled to obtain Teflon microparticles. Under aerobic conditions, the Teflon microparticles were irradiated with an electron beam generated by an accelerator or a cobalt source to obtain irradiated Teflon microparticles. P-doped graphene quantum dots were added and mixed evenly to obtain graphene quantum dot deposited Teflon microparticles.

[0009] S3. Preparation of graphene quantum dot deposited Teflon / SiO2 microcapsules: Graphene quantum dot deposited Teflon microparticles were added to dichloromethane and dispersed evenly. Composite silane was added and stirred evenly. The mixture was then added dropwise to water, heated and stirred to react, and spray-dried to obtain graphene quantum dot deposited Teflon / SiO2 microcapsules.

[0010] S4. Preparation of modified graphene quantum dot deposited Teflon / SiO2 microcapsules: Graphene quantum dot deposited Teflon / SiO2 microcapsules were added to Tris-HCl solution, dopamine hydrochloride was added, the mixture was heated and stirred to react, filtered, washed, and dried to obtain modified graphene quantum dot deposited Teflon / SiO2 microcapsules.

[0011] S5. Preparation of modified polyacrylic acid resin emulsion: Acrylic acid is added to water, NHS and EDC are added, and the mixture is stirred to activate it. Modified graphene quantum dot deposited Teflon / SiO2 microcapsules are added, and the mixture is stirred to react. After filtration, acrylic acid / modified graphene quantum dot deposited Teflon / SiO2 microcapsules are obtained. Acrylic acid / modified graphene quantum dot deposited Teflon / SiO2 microcapsules are added to water, methyl acrylate, styrene and an initiator are added, and the mixture is heated and stirred to react under an inert gas atmosphere to obtain modified polyacrylic acid resin emulsion.

[0012] S6. Preparation of UiO-66@boron nitride particles: Add boron nitride particles to ethanol, add silane coupling agent KH560, heat and stir to react, filter to obtain modified boron nitride particles, add modified boron nitride particles to acetone, add UiO-66-NH2, stir to react, filter, wash, dry to obtain UiO-66@boron nitride particles;

[0013] S7. Preparation of water-based Teflon coating: Modified polyacrylic resin emulsion, UiO-66@boron nitride particles, water, defoamer, dispersant, leveling agent and cosolvent are stirred and mixed evenly to obtain water-based Teflon coating.

[0014] As a further improvement of the present invention, the mass ratio of citric acid to phytic acid in step S1 is 17-20:2-3, the heating reaction temperature is 190-210℃, the time is 22-26h, and the dialysis bag used for dialysis has a pore size of 2500-3500Da.

[0015] As a further improvement of the present invention, the Teflon microparticles in step S2 have a particle size of less than 1µm, and the content of peroxy free radicals in the irradiated Teflon microparticles is 10. 12 -10 14 The spin number / g and the mass ratio of the irradiated Teflon microparticles to the P-doped graphene quantum dots are 10:2-3.

[0016] As a further improvement of the present invention, in step S3, the mass ratio of graphene quantum dot deposition of Teflon microparticles to composite silane is 4-6:7-10, the composite silane includes fluorinated silane and amino silane in a mass ratio of 5-8:4-6, the heating and stirring reaction temperature is 40-50℃, and the time is 4-7h, the fluorinated silane is selected from 1H,1H,2H,2H-perfluorodecyltriethoxysilane, 1H,1H,2H,2H-perfluorodecyltrimethoxysilane, dodecafluoroheptylpropyltrimethoxysilane, dodecafluoroheptylpropylmethyldimethoxysilane, and 3,3,3-trifluoropropylmethyldimethoxysilane. The aminosilane is selected from at least one of 3,3,3-trifluoropropyltrimethoxysilane, 1H,1H,2H,2H-perfluorooctyltriethoxysilane, or 1H,1H,2H,2H-perfluorooctyltrimethoxysilane, wherein the aminosilane is selected from at least one of γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-β(aminoethyl)-γ-aminopropyltrimethoxysilane, N-β(aminoethyl)-γ-aminopropyltriethoxysilane, N-β(aminoethyl)-γ-aminopropylmethyldimethoxysilane, N-β(aminoethyl)-γ-aminopropylmethyldiethoxysilane, and diethylenetriaminopropyltrimethoxysilane.

[0017] As a further improvement of the present invention, the pH value of the Tris-HCl solution in step S4 is 8.5-9.5, the mass ratio of the graphene quantum dot deposition Teflon / SiO2 microcapsules to dopamine hydrochloride is 10:3-5, and the temperature of the heating and stirring reaction is 55-65℃, and the time is 3-5h.

[0018] As a further improvement of the present invention, in step S5, the mass ratio of acrylic acid, N-hydroxysuccinimide, 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride, and modified graphene quantum dot deposited Teflon / SiO2 microcapsules is 3-5:1-2:1-2:6-9; the mass ratio of acrylic acid / modified graphene quantum dot deposited Teflon / SiO2 microcapsules, methyl acrylate, styrene, and initiator is 10:3-4:2-3:0.01-0.015; the initiator is selected from at least one of sodium persulfate, potassium persulfate, and ammonium persulfate; and the heating and stirring reaction temperature is 55-65°C, and the time is 4-6 hours.

[0019] As a further improvement of the present invention, the mass ratio of boron nitride particles to silane coupling agent KH560 in step S6 is 10:1-2, the temperature of the heating and stirring reaction is 40-50℃, the time is 2-4h, and the mass ratio of modified boron nitride particles to UiO-66-NH2 is 10:5-7.

[0020] As a further improvement of the present invention, the mass ratio of the modified polyacrylic acid resin emulsion, UiO-66@boron nitride particles, water, defoamer, dispersant, leveling agent, and cosolvent in step S7 is 100:5-10:20-30:1-2:1-3:2-3:0.5-1, wherein the defoamer is defoamer BYK020, the dispersant is N,N-dimethylethanolamine, the leveling agent is BYK333, and the cosolvent is propylene glycol monomethyl ether.

[0021] This invention further protects a water-based Teflon coating prepared by the above-described preparation method.

[0022] The present invention has the following beneficial effects:

[0023] This invention utilizes citric acid and phytic acid as sources to synthesize phosphorus-doped (P-doped) graphene quantum dots in a one-step process. Phytic acid serves as both a phosphorus source and a dopant. Its polyphosphate structure allows for efficient binding with subsequent materials, providing reaction sites. It can react with irradiated Teflon microparticles that, after electron beam or cobalt source irradiation of polytetrafluoroethylene (PTFE) powder, simultaneously generate two types of long-lived free radicals on the CC backbone and CF side chains. The P-doped graphene quantum dots contain abundant sp... 2 The carbon domain and edge carboxyl / hydroxyl groups, with their π-electron system, readily undergo addition or hydrogen abstraction reactions with free radicals to form stable covalent bonds, significantly improving the dispersibility of polytetrafluoroethylene micropowder in the aqueous phase, while also providing conductive / thermal pathways.

[0024] An interfacial hydrolysis-condensation method was employed, in which graphene quantum dot-deposited Teflon microparticles were encapsulated in a SiO2 shell using composite silanes. The fluorinated silanes exhibited affinity with the Teflon microparticles, forming a silane layer on their surface. An aminosilane layer covered the outermost layer. Upon dropletization into water, the outer surface, composed of amino groups, dispersed into small droplets during stirring. As the reaction proceeded, the amino groups underwent protonation, transforming into amphiphilic molecules, which further stabilized the silane droplets. Simultaneously, the protonation of the amino groups provided an alkaline environment, catalyzing the sol-gel process of the silanes to form a silica shell on their surface, thereby improving the wear resistance and mechanical strength of the Teflon.

[0025] The surface of the graphene quantum dot-deposited Teflon / SiO2 microcapsules was modified with polydopamine, exhibiting strong adhesion and abundant reactivity, providing a "bridge" for the covalent grafting of microcapsules with acrylic resin. The modified microcapsules were then in-situ coupled with acrylic monomers, followed by copolymerization with other monomers, making the microcapsules part of the polymer network. This achieved nanoscale uniform dispersion and strong interfacial bonding, fundamentally solving the compatibility and detachment problems.

[0026] This invention grows a metal-organic framework (UiO-66-NH2) on boron nitride modified with KH560, and achieves coupling through the reaction of amino and epoxy groups, creating an "organic-inorganic" hybrid reinforcement that combines the thermal conductivity, insulation, and lubrication of boron nitride with the high specific surface area and adsorption of UiO-66. This synergistically enhances the wear resistance, corrosion resistance, and density of the coating, greatly improving the performance of the coating.

[0027] The waterborne Teflon coating prepared by this invention overcomes the shortcomings of traditional Teflon coatings, such as the easy agglomeration of polytetrafluoroethylene in water-based systems, poor adhesion, insufficient hardness, poor wear resistance, and poor heat dissipation. The prepared waterborne Teflon has excellent mechanical properties, wear resistance, and suitable hardness, as well as good adhesion. At the same time, it has good heat dissipation and thermal conductivity, good water dispersibility, and is easy to store and transport. It also has the weather resistance characteristics of Teflon coatings and has broad application prospects. Detailed Implementation

[0028] The technical solutions in the embodiments of the present invention will be clearly and completely described below. 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 skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] Example 1

[0030] This embodiment provides a method for preparing a water-based Teflon coating, including the following steps:

[0031] S1. Preparation of P-doped graphene quantum dots: 17g citric acid and 2g phytic acid were mixed and dissolved in 250mL water, heated to 190℃, stirred for 22h, dialyzed for 12h using a dialysis bag with a pore size of 2500Da, and the unpermeable liquid was freeze-dried to obtain P-doped graphene quantum dots.

[0032] S2. Preparation of graphene quantum dot deposited Teflon microparticles: Teflon micro powder was ball-milled to obtain Teflon microparticles with a particle size of less than 1µm. Under aerobic conditions, the Teflon microparticles were irradiated with an electron beam generated by an accelerator to obtain irradiated Teflon microparticles. 10g of irradiated Teflon microparticles and 1g of P-doped graphene quantum dots were stirred and mixed for 20min to obtain graphene quantum dot deposited Teflon microparticles.

[0033] S3. Preparation of graphene quantum dot deposited Teflon / SiO2 microcapsules: 4g of graphene quantum dot deposited Teflon microparticles were added to 200mL of dichloromethane and ultrasonically dispersed at 1000W for 20min. 7g of composite silane was added and stirred until homogeneous. The mixture was then added dropwise to 500mL of water, heated to 40℃, stirred and reacted for 4h, and spray-dried to obtain graphene quantum dot deposited Teflon / SiO2 microcapsules.

[0034] The composite silane comprises 1H,1H,2H,2H-perfluorodecyltriethoxysilane and γ-aminopropyltrimethoxysilane in a mass ratio of 5:4.

[0035] S4. Preparation of modified graphene quantum dot deposited Teflon / SiO2 microcapsules: 10g of graphene quantum dot deposited Teflon / SiO2 microcapsules were added to 200mL of Tris-HCl solution with a pH of 8.5, 3g of dopamine hydrochloride was added, the mixture was heated to 55℃, stirred for 3h, filtered, washed, and dried to obtain modified graphene quantum dot deposited Teflon / SiO2 microcapsules;

[0036] S5. Preparation of modified polyacrylic acid resin emulsion: 3g of acrylic acid was added to 200mL of water, along with 1g of N-hydroxysuccinimide and 1g of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride. The mixture was stirred and activated at 0℃ for 30min. 6g of modified graphene quantum dot deposited Teflon / SiO2 microcapsules were added, and the mixture was stirred and reacted for 7h. After filtration, acrylic acid / modified graphene quantum dot deposited Teflon / SiO2 microcapsules were obtained. 10g of acrylic acid / modified graphene quantum dot deposited Teflon / SiO2 microcapsules were added to 100mL of water, along with 3g of methyl acrylate, 2g of styrene, and 0.01g of sodium persulfate. The mixture was heated to 55℃ under a nitrogen atmosphere and stirred and reacted for 4h to obtain the modified polyacrylic acid resin emulsion.

[0037] S6. Preparation of UiO-66@boron nitride particles: 10g of boron nitride particles were added to 150mL of ethanol, 1g of silane coupling agent KH560 was added, the mixture was heated to 40℃, stirred for 2h, filtered, and modified boron nitride particles were obtained. 10g of modified boron nitride particles were added to 150mL of acetone, 5g of UiO-66-NH2 was added, the mixture was stirred for 7h, filtered, washed, and dried to obtain UiO-66@boron nitride particles.

[0038] S7. Preparation of waterborne Teflon coating: 100g of modified polyacrylic acid resin emulsion, 5g of UiO-66@boron nitride particles, 20g of water, 1g of defoamer BYK020, 1g of N,N-dimethylethanolamine, 2g of leveling agent BYK333, and 0.5g of propylene glycol monomethyl ether are stirred and mixed evenly to obtain waterborne Teflon coating.

[0039] Example 2

[0040] This embodiment provides a method for preparing a water-based Teflon coating, including the following steps:

[0041] S1. Preparation of P-doped graphene quantum dots: 20g citric acid and 3g phytic acid were mixed and dissolved in 250mL water, heated to 210℃, stirred and reacted for 26h, dialyzed with a dialysis bag with a pore size of 3500Da for 12h, and the unpermeable liquid was freeze-dried to obtain P-doped graphene quantum dots.

[0042] S2. Preparation of graphene quantum dot deposited Teflon microparticles: Teflon micro powder was ball-milled to obtain Teflon microparticles with a particle size of less than 1µm. Under aerobic conditions, the Teflon microparticles were irradiated with a cobalt source to obtain irradiated Teflon microparticles. 10g of irradiated Teflon microparticles and 2g of P-doped graphene quantum dots were stirred and mixed for 40min to obtain graphene quantum dot deposited Teflon microparticles.

[0043] S3. Preparation of graphene quantum dot deposited Teflon / SiO2 microcapsules: 6g of graphene quantum dot deposited Teflon microparticles were added to 200mL of dichloromethane and ultrasonically dispersed at 1000W for 20min. 10g of composite silane was added and stirred until homogeneous. The mixture was then added dropwise to 500mL of water, heated to 50℃, stirred and reacted for 7h, and spray-dried to obtain graphene quantum dot deposited Teflon / SiO2 microcapsules.

[0044] The composite silane comprises 1H,1H,2H,2H-perfluorodecyltrimethoxysilane and N-β(aminoethyl)-γ-aminopropyltrimethoxysilane in a mass ratio of 8:6.

[0045] S4. Preparation of modified graphene quantum dot deposited Teflon / SiO2 microcapsules: 10g of graphene quantum dot deposited Teflon / SiO2 microcapsules were added to 200mL of Tris-HCl solution with a pH of 9.5, 5g of dopamine hydrochloride was added, the mixture was heated to 65℃, stirred for 5h, filtered, washed, and dried to obtain modified graphene quantum dot deposited Teflon / SiO2 microcapsules;

[0046] S5. Preparation of modified polyacrylic acid resin emulsion: 5g of acrylic acid was added to 200mL of water, along with 2g of N-hydroxysuccinimide and 2g of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride. The mixture was stirred and activated at 0℃ for 30min. 9g of modified graphene quantum dot deposited Teflon / SiO2 microcapsules were added and stirred for 10h. The mixture was then filtered to obtain acrylic acid / modified graphene quantum dot deposited Teflon / SiO2 microcapsules. 10g of acrylic acid / modified graphene quantum dot deposited Teflon / SiO2 microcapsules were added to 100mL of water, along with 4g of methyl acrylate, 3g of styrene, and 0.015g of ammonium persulfate. The mixture was heated to 65℃ under a nitrogen atmosphere and stirred for 6h to obtain the modified polyacrylic acid resin emulsion.

[0047] S6. Preparation of UiO-66@boron nitride particles: 10g of boron nitride particles were added to 150mL of ethanol, 2g of silane coupling agent KH560 was added, the mixture was heated to 50℃, stirred for 4h, filtered, and modified boron nitride particles were obtained. 10g of modified boron nitride particles were added to 150mL of acetone, 7g of UiO-66-NH2 was added, the mixture was stirred for 10h, filtered, washed, and dried to obtain UiO-66@boron nitride particles.

[0048] S7. Preparation of waterborne Teflon coating: 100g of modified polyacrylic acid resin emulsion, 10g of UiO-66@boron nitride particles, 30g of water, 2g of defoamer BYK020, 3g of N,N-dimethylethanolamine, 3g of leveling agent BYK333, and 1g of propylene glycol monomethyl ether are stirred and mixed evenly to obtain waterborne Teflon coating.

[0049] Example 3

[0050] This embodiment provides a method for preparing a water-based Teflon coating, including the following steps:

[0051] S1. Preparation of P-doped graphene quantum dots: 18g of citric acid and 2.5g of phytic acid were mixed and dissolved in 250mL of water, heated to 200℃, stirred and reacted for 24h, dialyzed with a dialysis bag with a pore size of 3000Da for 12h, and the unpermeated liquid was freeze-dried to obtain P-doped graphene quantum dots.

[0052] S2. Preparation of graphene quantum dot deposited Teflon microparticles: Teflon micro powder was ball-milled to obtain Teflon microparticles with a particle size of less than 1µm. Under aerobic conditions, the Teflon microparticles were irradiated with an electron beam generated by an accelerator or a cobalt source to obtain irradiated Teflon microparticles. 10g of irradiated Teflon microparticles and 1.5g of P-doped graphene quantum dots were stirred and mixed for 30min to obtain graphene quantum dot deposited Teflon microparticles.

[0053] S3. Preparation of graphene quantum dot deposited Teflon / SiO2 microcapsules: 5g of graphene quantum dot deposited Teflon microparticles were added to 200mL of dichloromethane and ultrasonically dispersed at 1000W for 20min. 8g of composite silane was added and stirred until homogeneous. The mixture was then added dropwise to 500mL of water, heated to 45℃, stirred and reacted for 5.5h, and spray-dried to obtain graphene quantum dot deposited Teflon / SiO2 microcapsules.

[0054] The composite silane comprises 1H,1H,2H,2H-perfluorooctyltrimethoxysilane and N-β(aminoethyl)-γ-aminopropylmethyldiethoxysilane in a mass ratio of 6:5.

[0055] S4. Preparation of modified graphene quantum dot deposited Teflon / SiO2 microcapsules: 10g of graphene quantum dot deposited Teflon / SiO2 microcapsules were added to 200mL of Tris-HCl solution with a pH of 9, 4g of dopamine hydrochloride was added, the mixture was heated to 60℃, stirred for 4h, filtered, washed, and dried to obtain modified graphene quantum dot deposited Teflon / SiO2 microcapsules;

[0056] S5. Preparation of modified polyacrylic acid resin emulsion: 4g of acrylic acid was added to 200mL of water, along with 1.5g of N-hydroxysuccinimide and 1.5g of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride. The mixture was stirred and activated at 0℃ for 30min. 7g of modified graphene quantum dot deposited Teflon / SiO2 microcapsules were added, and the mixture was stirred and reacted for 8h. After filtration, acrylic acid / modified graphene quantum dot deposited Teflon / SiO2 microcapsules were obtained. 10g of acrylic acid / modified graphene quantum dot deposited Teflon / SiO2 microcapsules were added to 100mL of water, along with 3.5g of methyl acrylate, 2.5g of styrene, and 0.012g of potassium persulfate. The mixture was heated to 60℃ under a nitrogen atmosphere and stirred and reacted for 5h to obtain the modified polyacrylic acid resin emulsion.

[0057] S6. Preparation of UiO-66@boron nitride particles: 10g of boron nitride particles were added to 150mL of ethanol, 1.5g of silane coupling agent KH560 was added, the mixture was heated to 45℃, stirred for 3h, filtered, and modified boron nitride particles were obtained. 10g of modified boron nitride particles were added to 150mL of acetone, 6g of UiO-66-NH2 was added, the mixture was stirred for 8h, filtered, washed, and dried to obtain UiO-66@boron nitride particles.

[0058] S7. Preparation of waterborne Teflon coating: 100g of modified polyacrylic acid resin emulsion, 7g of UiO-66@boron nitride particles, 25g of water, 1.5g of defoamer BYK020, 2g of N,N-dimethylethanolamine, 2.5g of leveling agent BYK333, and 0.7g of propylene glycol monomethyl ether are stirred and mixed evenly to obtain waterborne Teflon coating.

[0059] Comparative Example 1

[0060] The difference from Example 3 is that step S1 was not performed.

[0061] Specifically as follows:

[0062] S1. Preparation of Teflon microparticles: Teflon micro powder was ball-milled to obtain Teflon microparticles with a particle size of less than 1µm;

[0063] S2. Preparation of Teflon / SiO2 microcapsules: 5g of Teflon microparticles were added to 200mL of dichloromethane and ultrasonically dispersed at 1000W for 20min. 8g of composite silane was added and stirred until uniform. The mixture was then added dropwise to 500mL of water, heated to 45℃, stirred and reacted for 5.5h, and spray-dried to obtain Teflon / SiO2 microcapsules.

[0064] The composite silane comprises 1H,1H,2H,2H-perfluorooctyltrimethoxysilane and N-β(aminoethyl)-γ-aminopropylmethyldiethoxysilane in a mass ratio of 6:5.

[0065] S3. Preparation of modified Teflon / SiO2 microcapsules: 10g of Teflon / SiO2 microcapsules were added to 200mL of Tris-HCl solution with pH 9, 4g of dopamine hydrochloride was added, the mixture was heated to 60℃, stirred for 4h, filtered, washed, and dried to obtain modified Teflon / SiO2 microcapsules.

[0066] S4. Preparation of modified polyacrylic acid resin emulsion: 4g of acrylic acid was added to 200mL of water, along with 1.5g of N-hydroxysuccinimide and 1.5g of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride. The mixture was stirred and activated at 0℃ for 30min. 7g of modified Teflon / SiO2 microcapsules were added, and the mixture was stirred and reacted for 8h. After filtration, acrylic acid / modified Teflon / SiO2 microcapsules were obtained. 10g of acrylic acid / modified graphene quantum dot-deposited Teflon / SiO2 microcapsules were added to 100mL of water, along with 3.5g of methyl acrylate, 2.5g of styrene, and 0.012g of potassium persulfate. The mixture was heated to 60℃ under a nitrogen atmosphere and stirred and reacted for 5h to obtain the modified polyacrylic acid resin emulsion.

[0067] S5. Preparation of UiO-66@boron nitride particles: 10g of boron nitride particles were added to 150mL of ethanol, 1.5g of silane coupling agent KH560 was added, the mixture was heated to 45℃, stirred for 3h, filtered, and modified boron nitride particles were obtained. 10g of modified boron nitride particles were added to 150mL of acetone, 6g of UiO-66-NH2 was added, the mixture was stirred for 8h, filtered, washed, and dried to obtain UiO-66@boron nitride particles.

[0068] S6. Preparation of water-based Teflon coating: 100g of modified polyacrylic acid resin emulsion, 7g of UiO-66@boron nitride particles, 25g of water, 1.5g of defoamer BYK020, 2g of N,N-dimethylethanolamine, 2.5g of leveling agent BYK333, and 0.7g of propylene glycol monomethyl ether are stirred and mixed evenly to obtain water-based Teflon coating.

[0069] Comparative Example 2

[0070] The difference from Example 3 is that step S3 was not performed.

[0071] Specifically as follows:

[0072] S1. Preparation of P-doped graphene quantum dots: 18g of citric acid and 2.5g of phytic acid were mixed and dissolved in 250mL of water, heated to 200℃, stirred and reacted for 24h, dialyzed with a dialysis bag with a pore size of 3000Da for 12h, and the unpermeated liquid was freeze-dried to obtain P-doped graphene quantum dots.

[0073] S2. Preparation of graphene quantum dot deposited Teflon microparticles: Teflon micro powder was ball-milled to obtain Teflon microparticles with a particle size of less than 1µm. Under aerobic conditions, the Teflon microparticles were irradiated with an electron beam generated by an accelerator or a cobalt source to obtain irradiated Teflon microparticles. 10g of irradiated Teflon microparticles and 1.5g of P-doped graphene quantum dots were stirred and mixed for 30min to obtain graphene quantum dot deposited Teflon microparticles.

[0074] S3. Preparation of modified graphene quantum dot deposited Teflon microparticles: 10g of graphene quantum dot deposited Teflon microparticles were added to 200mL of Tris-HCl solution with pH 9, 4g of dopamine hydrochloride was added, the mixture was heated to 60℃, stirred for 4h, filtered, washed, and dried to obtain modified graphene quantum dot deposited Teflon microparticles.

[0075] S4. Preparation of modified polyacrylic acid resin emulsion: 4g of acrylic acid was added to 200mL of water, along with 1.5g of N-hydroxysuccinimide and 1.5g of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride. The mixture was stirred and activated at 0℃ for 30min. 7g of modified graphene quantum dot deposited Teflon microparticles were added, and the mixture was stirred and reacted for 8h. After filtration, acrylic acid / graphene quantum dot deposited Teflon microparticles were obtained. 10g of acrylic acid / graphene quantum dot deposited Teflon microparticles were added to 100mL of water, along with 3.5g of methyl acrylate, 2.5g of styrene, and 0.012g of potassium persulfate. The mixture was heated to 60℃ under a nitrogen atmosphere and stirred and reacted for 5h to obtain the modified polyacrylic acid resin emulsion.

[0076] S5. Preparation of UiO-66@boron nitride particles: 10g of boron nitride particles were added to 150mL of ethanol, 1.5g of silane coupling agent KH560 was added, the mixture was heated to 45℃, stirred for 3h, filtered, and modified boron nitride particles were obtained. 10g of modified boron nitride particles were added to 150mL of acetone, 6g of UiO-66-NH2 was added, the mixture was stirred for 8h, filtered, washed, and dried to obtain UiO-66@boron nitride particles.

[0077] S6. Preparation of water-based Teflon coating: 100g of modified polyacrylic acid resin emulsion, 7g of UiO-66@boron nitride particles, 25g of water, 1.5g of defoamer BYK020, 2g of N,N-dimethylethanolamine, 2.5g of leveling agent BYK333, and 0.7g of propylene glycol monomethyl ether are stirred and mixed evenly to obtain water-based Teflon coating.

[0078] Comparative Example 3

[0079] The difference from Example 3 is that step S4 was not performed.

[0080] Specifically as follows:

[0081] S1. Preparation of P-doped graphene quantum dots: 18g of citric acid and 2.5g of phytic acid were mixed and dissolved in 250mL of water, heated to 200℃, stirred and reacted for 24h, dialyzed with a dialysis bag with a pore size of 3000Da for 12h, and the unpermeated liquid was freeze-dried to obtain P-doped graphene quantum dots.

[0082] S2. Preparation of graphene quantum dot deposited Teflon microparticles: Teflon micro powder was ball-milled to obtain Teflon microparticles with a particle size of less than 1µm. Under aerobic conditions, the Teflon microparticles were irradiated with an electron beam generated by an accelerator or a cobalt source to obtain irradiated Teflon microparticles. 10g of irradiated Teflon microparticles and 1.5g of P-doped graphene quantum dots were stirred and mixed for 30min to obtain graphene quantum dot deposited Teflon microparticles.

[0083] S3. Preparation of graphene quantum dot deposited Teflon / SiO2 microcapsules: 5g of graphene quantum dot deposited Teflon microparticles were added to 200mL of dichloromethane and ultrasonically dispersed at 1000W for 20min. 8g of composite silane was added and stirred until homogeneous. The mixture was then added dropwise to 500mL of water, heated to 45℃, stirred and reacted for 5.5h, and spray-dried to obtain graphene quantum dot deposited Teflon / SiO2 microcapsules.

[0084] The composite silane comprises 1H,1H,2H,2H-perfluorooctyltrimethoxysilane and N-β(aminoethyl)-γ-aminopropylmethyldiethoxysilane in a mass ratio of 6:5.

[0085] S4. Preparation of modified polyacrylic acid resin emulsion: 4g of acrylic acid was added to 200mL of water, and 7g of graphene quantum dot deposited Teflon / SiO2 microcapsules were added. The mixture was stirred and reacted for 8h, then filtered to obtain acrylic acid / modified graphene quantum dot deposited Teflon / SiO2 microcapsules. 10g of acrylic acid / modified graphene quantum dot deposited Teflon / SiO2 microcapsules were added to 100mL of water, and 3.5g of methyl acrylate, 2.5g of styrene and 0.012g of potassium persulfate were added. The mixture was heated to 60℃ under a nitrogen atmosphere and stirred and reacted for 5h to obtain modified polyacrylic acid resin emulsion.

[0086] S5. Preparation of UiO-66@boron nitride particles: 10g of boron nitride particles were added to 150mL of ethanol, 1.5g of silane coupling agent KH560 was added, the mixture was heated to 45℃, stirred for 3h, filtered, and modified boron nitride particles were obtained. 10g of modified boron nitride particles were added to 150mL of acetone, 6g of UiO-66-NH2 was added, the mixture was stirred for 8h, filtered, washed, and dried to obtain UiO-66@boron nitride particles.

[0087] S6. Preparation of water-based Teflon coating: 100g of modified polyacrylic acid resin emulsion, 7g of UiO-66@boron nitride particles, 25g of water, 1.5g of defoamer BYK020, 2g of N,N-dimethylethanolamine, 2.5g of leveling agent BYK333, and 0.7g of propylene glycol monomethyl ether are stirred and mixed evenly to obtain water-based Teflon coating.

[0088] Comparative Example 4

[0089] The difference from Example 3 is that in step S6, UiO-66-NH2 and boron nitride particles are simply mixed.

[0090] Specifically as follows:

[0091] S1. Preparation of P-doped graphene quantum dots: 18g of citric acid and 2.5g of phytic acid were mixed and dissolved in 250mL of water, heated to 200℃, stirred and reacted for 24h, dialyzed with a dialysis bag with a pore size of 3000Da for 12h, and the unpermeated liquid was freeze-dried to obtain P-doped graphene quantum dots.

[0092] S2. Preparation of graphene quantum dot deposited Teflon microparticles: Teflon micro powder was ball-milled to obtain Teflon microparticles with a particle size of less than 1µm. Under aerobic conditions, the Teflon microparticles were irradiated with an electron beam generated by an accelerator or a cobalt source to obtain irradiated Teflon microparticles. 10g of irradiated Teflon microparticles and 1.5g of P-doped graphene quantum dots were stirred and mixed for 30min to obtain graphene quantum dot deposited Teflon microparticles.

[0093] S3. Preparation of graphene quantum dot deposited Teflon / SiO2 microcapsules: 5g of graphene quantum dot deposited Teflon microparticles were added to 200mL of dichloromethane and ultrasonically dispersed at 1000W for 20min. 8g of composite silane was added and stirred until homogeneous. The mixture was then added dropwise to 500mL of water, heated to 45℃, stirred and reacted for 5.5h, and spray-dried to obtain graphene quantum dot deposited Teflon / SiO2 microcapsules.

[0094] The composite silane comprises 1H,1H,2H,2H-perfluorooctyltrimethoxysilane and N-β(aminoethyl)-γ-aminopropylmethyldiethoxysilane in a mass ratio of 6:5.

[0095] S4. Preparation of modified graphene quantum dot deposited Teflon / SiO2 microcapsules: 10g of graphene quantum dot deposited Teflon / SiO2 microcapsules were added to 200mL of Tris-HCl solution with a pH of 9, 4g of dopamine hydrochloride was added, the mixture was heated to 60℃, stirred for 4h, filtered, washed, and dried to obtain modified graphene quantum dot deposited Teflon / SiO2 microcapsules;

[0096] S5. Preparation of modified polyacrylic acid resin emulsion: 4g of acrylic acid was added to 200mL of water, along with 1.5g of N-hydroxysuccinimide and 1.5g of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride. The mixture was stirred and activated at 0℃ for 30min. 7g of modified graphene quantum dot deposited Teflon / SiO2 microcapsules were added, and the mixture was stirred and reacted for 8h. After filtration, acrylic acid / modified graphene quantum dot deposited Teflon / SiO2 microcapsules were obtained. 10g of acrylic acid / modified graphene quantum dot deposited Teflon / SiO2 microcapsules were added to 100mL of water, along with 3.5g of methyl acrylate, 2.5g of styrene, and 0.012g of potassium persulfate. The mixture was heated to 60℃ under a nitrogen atmosphere and stirred and reacted for 5h to obtain the modified polyacrylic acid resin emulsion.

[0097] S6. Preparation of the mixture: 10g of boron nitride particles and 6g of UiO-66-NH2 were stirred and mixed to obtain the mixture;

[0098] S7. Preparation of water-based Teflon coating: 100g of modified polyacrylic acid resin emulsion, 7g of mixture, 25g of water, 1.5g of defoamer BYK020, 2g of N,N-dimethylethanolamine, 2.5g of leveling agent BYK333, and 0.7g of propylene glycol monomethyl ether are stirred and mixed evenly to obtain water-based Teflon coating.

[0099] Comparative Example 5

[0100] The difference from Example 3 is that UiO-66@boron nitride particles were not added in step S7.

[0101] Specifically as follows:

[0102] S1. Preparation of P-doped graphene quantum dots: 18g of citric acid and 2.5g of phytic acid were mixed and dissolved in 250mL of water, heated to 200℃, stirred and reacted for 24h, dialyzed with a dialysis bag with a pore size of 3000Da for 12h, and the unpermeated liquid was freeze-dried to obtain P-doped graphene quantum dots.

[0103] S2. Preparation of graphene quantum dot deposited Teflon microparticles: Teflon micro powder was ball-milled to obtain Teflon microparticles with a particle size of less than 1µm. Under aerobic conditions, the Teflon microparticles were irradiated with an electron beam generated by an accelerator or a cobalt source to obtain irradiated Teflon microparticles. 10g of irradiated Teflon microparticles and 1.5g of P-doped graphene quantum dots were stirred and mixed for 30min to obtain graphene quantum dot deposited Teflon microparticles.

[0104] S3. Preparation of graphene quantum dot deposited Teflon / SiO2 microcapsules: 5g of graphene quantum dot deposited Teflon microparticles were added to 200mL of dichloromethane and ultrasonically dispersed at 1000W for 20min. 8g of composite silane was added and stirred until homogeneous. The mixture was then added dropwise to 500mL of water, heated to 45℃, stirred and reacted for 5.5h, and spray-dried to obtain graphene quantum dot deposited Teflon / SiO2 microcapsules.

[0105] The composite silane comprises 1H,1H,2H,2H-perfluorooctyltrimethoxysilane and N-β(aminoethyl)-γ-aminopropylmethyldiethoxysilane in a mass ratio of 6:5.

[0106] S4. Preparation of modified graphene quantum dot deposited Teflon / SiO2 microcapsules: 10g of graphene quantum dot deposited Teflon / SiO2 microcapsules were added to 200mL of Tris-HCl solution with a pH of 9, 4g of dopamine hydrochloride was added, the mixture was heated to 60℃, stirred for 4h, filtered, washed, and dried to obtain modified graphene quantum dot deposited Teflon / SiO2 microcapsules;

[0107] S5. Preparation of modified polyacrylic acid resin emulsion: 4g of acrylic acid was added to 200mL of water, along with 1.5g of N-hydroxysuccinimide and 1.5g of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride. The mixture was stirred and activated at 0℃ for 30min. 7g of modified graphene quantum dot deposited Teflon / SiO2 microcapsules were added, and the mixture was stirred and reacted for 8h. After filtration, acrylic acid / modified graphene quantum dot deposited Teflon / SiO2 microcapsules were obtained. 10g of acrylic acid / modified graphene quantum dot deposited Teflon / SiO2 microcapsules were added to 100mL of water, along with 3.5g of methyl acrylate, 2.5g of styrene, and 0.012g of potassium persulfate. The mixture was heated to 60℃ under a nitrogen atmosphere and stirred and reacted for 5h to obtain the modified polyacrylic acid resin emulsion.

[0108] S6. Preparation of water-based Teflon coating: 100g of modified polyacrylic acid resin emulsion, 25g of water, 1.5g of defoamer BYK020, 2g of N,N-dimethylethanolamine, 2.5g of leveling agent BYK333, and 0.7g of propylene glycol monomethyl ether are stirred and mixed evenly to obtain water-based Teflon coating.

[0109] Test Example 1

[0110] The water-based Teflon coatings prepared in Examples 1-3 and Comparative Examples 1-5 were applied by spraying. The spraying pressure was 0.5 MPa, the spray gun nozzle diameter was 1 mm, the spraying distance was 25 cm, and the wet film was placed in an oven at 380°C for 20 min to cure. The coating thickness was 40-50 µm.

[0111] The pencil hardness test was conducted according to GB / T6739-2022, and the result was assessed as: paint film scratch.

[0112] Adhesion testing was conducted according to GB / T9286-2021, with a spacing of 1 mm.

[0113] Heat resistance was determined according to GB / T1735-2009 standard. Test conditions: 280℃×2h. Result evaluation: color difference ≤1 is qualified.

[0114] The electromagnetic heating efficiency test involves heating coated iron cookware on an induction cooker and measuring the percentage of actual output power to input power as the electromagnetic heating efficiency.

[0115] The abrasion resistance of the coating was tested using a Taber tester with a load of 1 kg, a rotation speed of 60 r / min, and a rotation number of 1000 rpm.

[0116] The lubricity of the coating was tested using an MS-M9000 reciprocating friction and wear tester with a friction load of 20 N, a sliding distance of 5 mm, a frequency of 0.5 Hz, and a friction time of 30 min.

[0117] The corrosion resistance of the coating in a neutral salt spray environment was tested using a salt spray tester.

[0118] The results are shown in Table 1.

[0119] Table 1

[0120]

[0121] As can be seen from the table above, the water-based Teflon coatings prepared in Examples 1-3 of this invention have good overall performance.

[0122] The above description is only a preferred embodiment of the present invention and is 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 method for preparing an aqueous Teflon coating, characterized by, The P-doped graphene quantum dots are deposited on Teflon microparticles, embedded in a SiO2 shell, and modified on the surface by polydopamine, then reacted with acrylic acid, and then polymerized to prepare a modified polyacrylic acid resin emulsion, which is uniformly mixed with UiO-66@boron nitride particles, water, a defoaming agent, a dispersing agent, a leveling agent, and a cosolvent to prepare a water-based Teflon coating. The method comprises the following steps: S1. Preparation of P-doped graphene quantum dots: citric acid and phytic acid are mixed in water, heated and reacted, dialyzed, and the undialyzed liquid is freeze-dried to obtain P-doped graphene quantum dots. S2. Preparation of graphene quantum dot-deposited Teflon microparticles: Teflon micropowder is ground by ball milling to obtain Teflon microparticles, which are irradiated with an electron beam or a cobalt source under aerobic conditions to obtain irradiated Teflon microparticles, and then P-doped graphene quantum dots are added and uniformly mixed to obtain graphene quantum dot-deposited Teflon microparticles. S3. Preparation of graphene quantum dot-deposited Teflon / SiO2 microcapsules: graphene quantum dot-deposited Teflon microparticles are added to dichloromethane, uniformly dispersed, a composite silane is added, uniformly stirred and mixed, and then water is added dropwise, heated and stirred to react, and then spray dried to obtain graphene quantum dot-deposited Teflon / SiO2 microcapsules. S4. Preparation of modified graphene quantum dot-deposited Teflon / SiO2 microcapsules: graphene quantum dot-deposited Teflon / SiO2 microcapsules are added to a Tris-HCl solution, and hydrochloric acid dopamine is added, heated and stirred to react, filtered, washed, and dried to obtain modified graphene quantum dot-deposited Teflon / SiO2 microcapsules. S5. Preparation of modified polyacrylic acid resin emulsion: acrylic acid is added to water, N-hydroxysuccinimide and 1-ethyl-(3-dimethylaminopropyl) carbonyldiimidazole hydrochloride are added, stirred and activated, modified graphene quantum dot-deposited Teflon / SiO2 microcapsules are added, stirred and reacted, filtered, and then acrylic acid / modified graphene quantum dot-deposited Teflon / SiO2 microcapsules are obtained, which are added to water, methyl acrylate, styrene, and an initiator, heated and stirred to react under an inert gas atmosphere, and then a modified polyacrylic acid resin emulsion is obtained. S6. Preparation of UiO-66@boron nitride particles: boron nitride particles are added to ethanol, silane coupling agent KH560 is added, heated and stirred to react, filtered, and then modified boron nitride particles are obtained, which are added to acetone, UiO-66-NH2 is added, stirred and reacted, filtered, washed, and dried to obtain UiO-66@boron nitride particles. S7. Preparation of water-based Teflon coating: the modified polyacrylic acid resin emulsion, UiO-66@boron nitride particles, water, defoaming agent, dispersing agent, leveling agent, and cosolvent are uniformly stirred and mixed to obtain a water-based Teflon coating.

2. The production method according to claim 1, characterized by, In step S1, the mass ratio of citric acid to phytic acid is 17-20:2-3, the temperature of the heating reaction is 190-210℃, and the time is 22-26h, and the dialysis bag has a pore size of 2500-3500Da.

3. The preparation method according to claim 1, characterized in that, The particle size of the Teflon microparticles in step S2 is less than 1 µm, and the content of the peroxide free radicals in the irradiated Teflon microparticles is 10 12 -10 14 The number of spins / g, the mass ratio of the irradiated Teflon microparticles, and the P-doped graphene quantum dots is 10:2-3.

4. The method of claim 1, wherein, The mass ratio of the graphene quantum dot deposition Teflon particles and the composite silane in step S3 is 4-6:7-10, the composite silane includes fluorine-containing silane and amino silane, the mass ratio is 5-8:4-6, the temperature of the heating and stirring reaction is 40-50℃, the time is 4-7h, the fluorine-containing silane is at least one selected from 1H,1H,2H,2H-perfluorodecyltriethoxysilane, 1H,1H,2H,2H-perfluorodecyltrimethoxysilane, dodecafluoroheptylpropyltrimethoxysilane, dodecafluoroheptylpropylmethyldimethoxysilane, 3,3,3-trifluoropropylmethyldimethoxysilane, 3,3,3-trifluoropropyltrimethoxysilane, 1H,1H,2H,2H-perfluorooctyltriethoxysilane or 1H,1H,2H,2H-perfluorooctyltrimethoxysilane, and the amino silane is at least one selected from γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-β(aminoethyl)-γ-aminopropyltrimethoxysilane, N-β(aminoethyl)-γ-aminopropyltriethoxysilane, N-β(aminoethyl)-γ-aminopropylmethyldimethoxysilane, N-β(aminoethyl)-γ-aminopropylmethyldiethoxysilane, diethylenetriaminepropyltrimethoxysilane.

5. The preparation method according to claim 1, characterized in that, The pH value of the Tris-HCl solution in step S4 is 8.5-9.5, the mass ratio of the graphene quantum dot deposition Teflon / SiO2 microcapsule and dopamine hydrochloride is 10:3-5, the temperature of the heating and stirring reaction is 55-65℃, and the time is 3-5h.

6. The method of claim 1, wherein, The mass ratio of the acrylic acid, N-hydroxysuccinimide, 1-ethyl-(3-dimethylaminopropyl) carbonyldiimidazole hydrochloride and modified graphene quantum dot deposition Teflon / SiO2 microcapsule in step S5 is 3-5:1-2:1-2:6-9, the mass ratio of the acrylic acid / modified graphene quantum dot deposition Teflon / SiO2 microcapsule, methyl acrylate, styrene and initiator is 10:3-4:2-3:0.01-0.015, the initiator is at least one selected from sodium persulfate, potassium persulfate and ammonium persulfate, the temperature of the heating and stirring reaction is 55-65℃, and the time is 4-6h.

7. The preparation method according to claim 1, characterized in that, The mass ratio of the boron nitride particles and silane coupling agent KH560 in step S6 is 10:1-2, the temperature of the heating and stirring reaction is 40-50℃, and the time is 2-4h, the mass ratio of the modified boron nitride particles and UiO-66-NH2 is 10:5-7.

8. The method of claim 1, wherein, The mass ratio of the modified polyacrylic resin emulsion, UiO-66@boron nitride particles, water, defoaming agent, dispersant, leveling agent, cosolvent in step S7 is 100:5-10:20-30:1-2:1-3:2-3:0.5-1, the defoaming agent is defoaming agent BYK020, the dispersant is N,N-dimethylethanolamine, the leveling agent is BYK333, and the cosolvent is propylene glycol monomethyl ether.

9. An aqueous Teflon coating prepared by the method of any one of claims 1-8.

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