Composite modified Teflon coating as well as preparation method and application thereof

Abstract

The invention provides a composite modified Teflon coating as well as a preparation method and application thereof, and belongs to the technical field of coatings. The preparation method comprises the following steps: preparing a molybdenum carbide / graphite / carbon fiber composite material, siliconizing, recarburizing, modifying with oleic acid, mixing with a silane coupling agent modified ultraviolet light absorber UV-328, adding into a polytetrafluoroethylene emulsion, adding an acrylic monomer, and carrying out polymerization reaction to prepare the composite modified Teflon coating. According to the invention, an emulsion polymerization method is adopted, polytetrafluoroethylene, acrylate and a modified material are introduced for copolymerization, a series of composite emulsion coatings with different contents are prepared, the thermal stability, high temperature resistance, weather resistance, ultraviolet light aging resistance and wear resistance of the coatings are improved, the color fastness of the coatings is high, the washing resistance and the solarization resistance are good, and the service life of the coatings is prolonged. And in addition, certain hydrophobicity is achieved, and wide application prospects are achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of paint, in particular to a composite modified Teflon paint and its preparation method and application. BACKGROUND

[0002] Paint printing is a simple and fast coloring method, which has the characteristics of short process flow, simple preparation of printing paste, wide application range, energy saving and environmental protection, etc., and is one of the key development objects in the field of textile printing and dyeing. However, pigment particles lack affinity to fibers, and need to be attached to the surface of the fabric with the help of adhesives. The color fastness and light fastness of paint printed fabric are closely related to the performance of the adhesive. At present, water-based polyacrylate adhesives are used more in paint printing because of their good adhesion, bright color, low pollution and low cost. However, polyacrylate has the problems of poor water resistance, hot adhesion and cold brittleness, and the color fastness of paint printed fabric is poor, which will appear yellowing in high temperature and outdoor sunlight environment, and cannot meet the use requirements of outdoor textiles. Polytetrafluoroethylene (PTFE) has the advantages of chemical stability, corrosion resistance and weather resistance. Coating it on the surface of the fabric can improve the weather resistance and hydrophobicity of the fabric. However, there is inertia between PTFE and other materials, and the compatibility is poor, and the dispersion effect is not ideal. PTFE has poor wettability on the water contact surface due to its small surface tension, so it has no adhesion. Therefore, polytetrafluoroethylene / polyacrylate composite latex can be prepared by using polyacrylate, which can complement each other in performance, improve the dispersion and adhesion of polytetrafluoroethylene, and synthesize an ideal adhesive for paint. However, it still has poor wear resistance, and because it is mixed with polyacrylate resin, its ultraviolet resistance is reduced, and it also has poor high temperature resistance and poor thermal conductivity. SUMMARY

[0003] The purpose of the present application is to provide a composite modified Teflon paint and its preparation method and application. By using emulsion polymerization method, introducing polytetrafluoroethylene and acrylate and modified materials for copolymerization, a series of composite emulsion paint with different content is prepared, which improves the thermal stability, high temperature resistance, weather resistance, ultraviolet light aging resistance and wear resistance of the paint. The paint has high color fastness, good water washing resistance and sunlight resistance, and has certain hydrophobicity, which has wide application prospect.

[0004] The technical solution of the present application is as follows:

[0005] The present application provides a preparation method of a composite modified Teflon paint. After preparing the molybdenum carbide / graphite / carbon fiber composite material, the oil is modified, mixed with the ultraviolet absorber UV-328 modified by the silane coupling agent, added into the polytetrafluoroethylene emulsion, added with the acrylic monomer, and polymerized to prepare the composite modified Teflon paint.

[0006] As a further improvement of the present application, the following steps are included:

[0007] S1. Preparation of molybdenum carbide / graphite / carbon fiber composite: After ball milling of molybdenum carbide, expandable graphite and carbon fiber are added, and plasma-assisted ball milling is performed to obtain a composite;

[0008] S2. Carbon addition: The composite is carbonized under nitrogen protection using natural gas as the carbon source by chemical vapor deposition process to obtain a high-density composite;

[0009] S3. Silicon infiltration: The high-density composite is subjected to molten silicon infiltration, crushing, and ball milling to obtain a high-density composite molybdenum carbon ceramic material;

[0010] S4. Oleic acid modification: The high-density composite molybdenum carbon ceramic powder is mixed with oleic acid, and plasma-assisted ball milling is performed to obtain modified high-density composite molybdenum carbon ceramic powder;

[0011] S5. Modification of ultraviolet absorber UV-328: Ultraviolet absorber UV-328 is added to ethanol, and silane coupling agent KH570 is added, and heated and stirred to react to obtain modified ultraviolet absorber UV-328;

[0012] S6. Hydrolysis: The modified ultraviolet absorber UV-328 is added to water, the pH value of the solution is adjusted, and the solution is stirred to hydrolyze to obtain hydrolyzed modified ultraviolet absorber UV-328;

[0013] S7. Preparation of composite modified Teflon coating: Emulsifier, pH buffer, and polytetrafluoroethylene emulsion are prepared into an aqueous phase emulsion, heated and stirred to mix, long-chain alkyl acrylate, methyl methacrylate, butyl acrylate, modified high-density composite molybdenum carbon ceramic powder, and hydrolyzed modified ultraviolet absorber UV-328 are added and stirred uniformly, initiator is added, stirred to react, filtered, discharged, and composite modified Teflon coating is obtained.

[0014] As a further improvement of the present application, the mass ratio of molybdenum carbide, expandable graphite and carbon fiber in step S1 is 3-5:1-2:0.5-1, and the power parameters of the plasma are: discharge voltage 20-24kV, discharge frequency 10-15kHz.

[0015] As a further improvement of the present application, the carbon source of the chemical vapor deposition process in step S2 is natural gas or propane gas, the deposition temperature of the carbon addition is 1000-1200℃, and the time is 44-52h; the density of the composite molybdenum carbon ceramic material in step S3 is 2.3-2.5g / cm 3 .

[0016] As a further improvement of the application, the mass ratio of the high-density composite molybdenum-carbon ceramic powder and oleic acid in step S4 is 5-7:2-4, and the power parameters of the plasma are as follows: discharge voltage 20-24 kV and discharge frequency 10-15 kHz.

[0017] As a further improvement of the application, the mass ratio of the ultraviolet absorber UV-328 and the silane coupling agent KH570 in step S5 is 8-10:2-3, the temperature of the heating and stirring reaction is 50-60°C, and the time is 2-3 h.

[0018] As a further improvement of the application, the pH value of the adjusting solution in step S6 is 9-10, and the time of the stirring and hydrolysis is 7-10 h.

[0019] As a further improvement of the application, the mass ratio of the emulsifier, the pH buffer, the polytetrafluoroethylene emulsion, the long-chain alkyl acrylate, the methyl methacrylate, the butyl acrylate, the modified high-density composite molybdenum-carbon ceramic powder, the hydrolysis-modified ultraviolet absorber UV-328 and the initiator in step S7 is 0.2-0.3:0.5-1:4-6:3-5:8-10:0.5-1:2-4:0.5-1:0.001-0.0015, the emulsifier is at least one selected from the group consisting of Span-20, Span-40, Span-60, Span-80 and Span-85, the pH buffer is sodium bicarbonate or sodium carbonate, the initiator is at least one selected from the group consisting of ammonium persulfate, potassium persulfate and sodium persulfate, the long-chain alkyl acrylate is at least one selected from the group consisting of 2-ethylhexyl acrylate and lauryl acrylate, the time of the stirring reaction is 7-10 h, and the temperature of the heating is 75-80°C.

[0020] The application further protects a composite modified Teflon coating prepared by the above preparation method.

[0021] The application further protects the use of the above composite modified Teflon coating in fabric coating. Such fabrics have very high requirements for wear resistance, such as being applied to extreme sports and outdoor equipment, protective clothing, military uniforms, combat uniforms and some special functional equipment.

[0022] The application has the following beneficial effects:

[0023] In the application, molybdenum carbide, graphite and carbon fibers are mixed and ball milled to prepare a composite material. The graphite and carbon fibers wrap the molybdenum carbide into a core-shell structure composite, and the molybdenum carbide is embedded in the coating as a hard phase, which can significantly reduce the wear amount, enhance the high-temperature resistance and oxidation resistance, and improve the corrosion resistance. The plasma can generate active groups (such as hydroxyl and carboxyl) on the surface of the particles, break the molybdenum carbide agglomerates and enhance the interfacial bonding force between the molybdenum carbide, graphite and carbon fibers. Meanwhile, the uniform dispersion of the carbon fibers can construct a three-dimensional support network, which provides a mechanical enhancement basis for the subsequent coating.

[0024] Under the action of chemical vapor deposition, carbonation and densification, precise filling of pores, and under the action of silicon infiltration, silicon reacts with carbon to form SiC phase and form a "Mo2C-SiC-graphite" multi-component system with molybdenum carbide, forming a high-density composite molybdenum carbon ceramic material, which not only has good wear resistance, thermal conductivity and the advantage of reducing the friction coefficient of the coating, but also improves the high temperature resistance of the coating.

[0025] Oleic acid is combined with the surface of high-density composite molybdenum carbon ceramic powder through a hydrophobic chain, converting the "hydrophilic surface" of inorganic powder into a "hydrophobic surface", so that it can be uniformly dispersed in the polytetrafluoroethylene water-based emulsion, avoiding the "layering and agglomeration" problem when traditional inorganic powder is mixed with organic emulsion, and improving the surface uniformity of the coating after curing.

[0026] The siloxane group of KH570 is combined with the active site of UV-328, and the double bond group can undergo copolymerization reaction with long-chain alkyl acrylate, methyl methacrylate and other monomers, so as to uniformly fix the ultraviolet absorber UV-328 in the coating crosslinking network, solve the problem of easy migration and loss of traditional UV absorber, and prolong the ultraviolet aging life of the coating. After the modified ultraviolet absorber UV-328 is hydrolyzed, the silane chain becomes a silanol structure, improving the adsorption force on the surface of the fabric, thereby improving the washing resistance and color fastness, and having the characteristics of good flexibility.

[0027] The emulsion polymerization method is adopted in the application, polytetrafluoroethylene, acrylate and modified materials are copolymerized to prepare a series of composite emulsion coatings with different contents, and the thermal stability, high temperature resistance, weather resistance, ultraviolet light aging resistance and wear resistance of the coating are improved. The coating has high color fastness, good water washing resistance and sunlight resistance, and has certain hydrophobicity, and has wide application prospect. BRIEF DESCRIPTION OF DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0029] Figure 1 TEM image of the composite modified Teflon coating prepared in Example 1. DETAILED DESCRIPTION

[0030] The technical solutions in the embodiments of the present application will be clearly and completely described below. Obviously, the described embodiments are only a part 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 efforts belong to the scope of the present application.

[0031] Embodiment 1

[0032] The embodiment provides a preparation method of a composite modified Teflon coating, comprising the following steps:

[0033] S1. Preparation of molybdenum carbide / graphite / carbon fiber composite: 3g of molybdenum carbide is ball milled for 1h, then 1g of expanded graphite and 0.5g of carbon fiber are added, and plasma-assisted ball milling is performed for 10h, with the power parameters of the plasma being: discharge voltage 20kV and discharge frequency 10kHz, to obtain a composite;

[0034] S2. Carbon increase: the composite is subjected to carbon increase by using a chemical vapor deposition process under the protection of nitrogen, with natural gas as a carbon source, the deposition temperature being 1000℃, and the time being 44h, to obtain a high-density composite;

[0035] S3. Silicon infiltration: the high-density composite is subjected to melt silicon infiltration, is crushed, and is ball milled for 6h, to obtain a high-density composite molybdenum-carbon ceramic material with a density of 2.3g / cm 3 ;

[0036] S4. Oleic acid modification: 5g of the high-density composite molybdenum-carbon ceramic powder is mixed with 2g of oleic acid, and plasma-assisted ball milling is performed for 15h, with the power parameters of the plasma being: discharge voltage 20kV and discharge frequency 10kHz, to obtain modified high-density composite molybdenum-carbon ceramic powder;

[0037] S5. Modification of ultraviolet absorber UV-328: 0.8g of ultraviolet absorber UV-328 is added into 50mL of ethanol, 0.2g of silane coupling agent KH570 is added, heating is performed to 50℃, and stirring reaction is performed for 2h, to obtain modified ultraviolet absorber UV-328;

[0038] S6. Hydrolysis: 1g of the modified ultraviolet absorber UV-328 is added into 50mL of water, the pH value of the solution is adjusted to 9, and stirring hydrolysis is performed for 7h, to obtain hydrolyzed modified ultraviolet absorber UV-328;

[0039] S7. Preparation of composite modified Teflon coating: 0.2g of Span-20, 0.5g of sodium carbonate, 4g of polytetrafluoroethylene emulsion was added to 200mL of water to prepare an aqueous emulsion, heated to 75℃, stirred and mixed, 3g of lauryl acrylate, 8g of methyl methacrylate, 0.5g of butyl acrylate, 2g of modified high-density composite molybdenum carbon ceramic powder, 0.5g of hydrolyzed modified ultraviolet absorber UV-328, stirred and mixed for 30min, 0.001g of ammonium persulfate was added, stirred and reacted for 7h, filtered, discharged, and the composite modified Teflon coating was prepared, Figure 1 The TEM image of the prepared coating shows that it has a core-shell structure and good dispersion, and no agglomeration occurs.

[0040] Example 2

[0041] The present embodiment provides a preparation method of a composite modified Teflon coating, comprising the following steps:

[0042] S1. Preparation of molybdenum carbide / graphite / carbon fiber composite: 5g of molybdenum carbide was ball milled for 1h, then 2g of expanded graphite and 1g of carbon fiber were added, and plasma assisted ball milling was performed for 12h, with the power parameters of the plasma being: discharge voltage 24kV, discharge frequency 15kHz, to obtain a composite;

[0043] S2. Carbonization: The composite was carbonized under nitrogen protection using natural gas as the carbon source by chemical vapor deposition process, with the deposition temperature being 1200℃ and the time being 52h, to obtain a high-density composite;

[0044] S3. Silicon infiltration: The high-density composite was subjected to melt silicon infiltration, crushed, and ball milled for 6h to obtain a high-density composite molybdenum carbon ceramic material with a density of 2.35g / cm 3 ;

[0045] S4. Oleic acid modification: 7g of high-density composite molybdenum carbon ceramic powder was mixed with 4g of oleic acid, and plasma assisted ball milling was performed for 25h, with the power parameters of the plasma being: discharge voltage 24kV, discharge frequency 15kHz, to obtain modified high-density composite molybdenum carbon ceramic powder;

[0046] S5. Modification of ultraviolet absorber UV-328: 1g of ultraviolet absorber UV-328 was added to 50mL of ethanol, 0.3g of silane coupling agent KH570 was added, heated to 60℃, and stirred and reacted for 3h to obtain modified ultraviolet absorber UV-328;

[0047] S6. Hydrolysis: 1g of modified ultraviolet absorber UV-328 was added to 50mL of water, the pH value of the solution was adjusted to 10, and stirred and hydrolyzed for 10h to obtain hydrolyzed modified ultraviolet absorber UV-328;

[0048] S7. Preparation of composite modified Teflon coating: 0.3g of Span-40, 1g of sodium bicarbonate, 6g of polytetrafluoroethylene emulsion was added to 200mL of water to prepare an aqueous emulsion, heated to 80℃, stirred and mixed, 5g of lauryl acrylate, 10g of methyl methacrylate, 1g of butyl acrylate, 4g of modified high-density composite molybdenum carbon ceramic powder, 1g of hydrolyzed modified ultraviolet absorber UV-328 was added, stirred and mixed for 30min, 0.0015g of potassium persulfate was added, stirred and reacted for 10h, filtered, discharged, and the composite modified Teflon coating was prepared.

[0049] Example 3

[0050] The present embodiment provides a preparation method of a composite modified Teflon coating, comprising the following steps:

[0051] S1. Preparation of molybdenum carbide / graphite / carbon fiber composite: 4g of molybdenum carbide was ball milled for 1h, then 1.5g of expanded graphite and 0.7g of carbon fiber were added, and plasma assisted ball milling was performed for 11h, with the power parameters of the plasma being: discharge voltage 22kV, discharge frequency 12kHz, to obtain a composite;

[0052] S2. Carbon addition: The composite was carbonized under nitrogen protection using natural gas as the carbon source by chemical vapor deposition process, with the deposition temperature being 1100℃ and the time being 48h, to obtain a high-density composite;

[0053] S3. Silicon infiltration: The high-density composite was subjected to melt silicon infiltration, crushed, and ball milled for 6h to obtain a high-density molybdenum carbon ceramic material with a density of 2.33g / cm 3 ;

[0054] S4. Oleic acid modification: 6g of high-density composite molybdenum carbon ceramic powder was mixed with 3g of oleic acid, and plasma assisted ball milling was performed for 20h, with the power parameters of the plasma being: discharge voltage 22kV, discharge frequency 12kHz, to obtain modified high-density composite molybdenum carbon ceramic powder;

[0055] S5. Modification of ultraviolet absorber UV-328: 0.9g of ultraviolet absorber UV-328 was added to 50mL of ethanol, 0.25g of silane coupling agent KH570 was added, heated to 55℃, and stirred and reacted for 2.5h to obtain modified ultraviolet absorber UV-328;

[0056] S6. Hydrolysis: 1g of modified ultraviolet absorber UV-328 was added to 50mL of water, the pH value of the solution was adjusted to 9.5, and stirred and hydrolyzed for 8h to obtain hydrolyzed modified ultraviolet absorber UV-328;

[0057] S7. Preparation of composite modified Teflon coating: 0.25 g of Span-85, 0.7 g of sodium bicarbonate, 5 g of polytetrafluoroethylene emulsion were added to 200 mL of water to prepare an aqueous emulsion, heated to 77°C, stirred and mixed, 4 g of lauryl acrylate, 9 g of methyl methacrylate, 0.7 g of butyl acrylate, 3 g of modified high-density composite molybdenum carbon ceramic powder, 0.7 g of hydrolyzed modified ultraviolet absorber UV-328 were added, stirred and mixed for 30 min, 0.0012 g of sodium persulfate was added, stirred and reacted for 8 h, filtered, discharged, and the composite modified Teflon coating was prepared.

[0058] Comparative Example 1

[0059] Compared with Example 3, the difference is that no molybdenum carbide is added in step S1.

[0060] The details are as follows:

[0061] S1. Preparation of graphite / carbon fiber composite: 1.5 g of expanded graphite and 0.7 g of carbon fiber were plasma assisted ball milled for 11 h, and the power parameters of the plasma were: discharge voltage 22 kV, discharge frequency 12 kHz, to prepare the composite.

[0062] S2. Carbonization: the composite was carbonized under nitrogen protection using natural gas as the carbon source by chemical vapor deposition process, the deposition temperature was 1100°C, and the time was 48 h, to obtain a high-density composite;

[0063] S3. Silicon infiltration: the high-density composite was subjected to melt silicon infiltration, crushed, and ball milled for 6 h to obtain a high-density composite molybdenum carbon ceramic material with a density of 2.33 g / cm 3 ;

[0064] S4. Oleic acid modification: 6 g of high-density composite molybdenum carbon ceramic powder was mixed with 3 g of oleic acid, and plasma assisted ball milled for 20 h, and the power parameters of the plasma were: discharge voltage 22 kV, discharge frequency 12 kHz, to prepare the modified high-density composite molybdenum carbon ceramic powder;

[0065] S5. Modification of ultraviolet absorber UV-328: 0.9 g of ultraviolet absorber UV-328 was added to 50 mL of ethanol, 0.25 g of silane coupling agent KH570 was added, heated to 55°C, and stirred and reacted for 2.5 h to prepare the modified ultraviolet absorber UV-328;

[0066] S6. Hydrolysis: 1 g of modified ultraviolet absorber UV-328 was added to 50 mL of water, the pH value of the solution was adjusted to 9.5, and stirred and hydrolyzed for 8 h to prepare the hydrolyzed modified ultraviolet absorber UV-328;

[0067] S7. Preparation of composite modified Teflon coating: 0.25 g of Span-85, 0.7 g of sodium bicarbonate, 5 g of polytetrafluoroethylene emulsion were added to 200 mL of water to prepare an aqueous emulsion, heated to 77°C, mixed with stirring, 4 g of lauryl acrylate, 9 g of methyl methacrylate, 0.7 g of butyl acrylate, 3 g of modified high-density composite molybdenum-carbon ceramic powder, 0.7 g of hydrolyzed modified ultraviolet absorber UV-328 were added, mixed with stirring for 30 min, 0.0012 g of sodium persulfate was added, and stirred for 8 h, filtered, discharged, and the composite modified Teflon coating was prepared.

[0068] Comparative Example 2

[0069] The difference compared with Example 3 is that step S2 is not performed.

[0070] The details are as follows:

[0071] S1. Preparation of molybdenum carbide / graphite / carbon fiber composite: 4 g of molybdenum carbide was ball milled for 1 h, then 1.5 g of expanded graphite and 0.7 g of carbon fiber were added, and plasma-assisted ball milling was performed for 11 h, with the power parameters of the plasma being: discharge voltage 22 kV, discharge frequency 12 kHz, to prepare the composite;

[0072] S2. Silicon infiltration: the composite was subjected to molten silicon infiltration, crushed, and ball milled for 6 h to obtain the composite molybdenum-carbon ceramic material;

[0073] S3. Oleic acid modification: 6 g of the composite molybdenum-carbon ceramic powder was mixed with 3 g of oleic acid, and plasma-assisted ball milling was performed for 20 h, with the power parameters of the plasma being: discharge voltage 22 kV, discharge frequency 12 kHz, to prepare the modified composite molybdenum-carbon ceramic powder;

[0074] S4. Modification of ultraviolet absorber UV-328: 0.9 g of ultraviolet absorber UV-328 was added to 50 mL of ethanol, 0.25 g of silane coupling agent KH570 was added, heated to 55°C, and stirred for 2.5 h to prepare the modified ultraviolet absorber UV-328;

[0075] S5. Hydrolysis: 1 g of the modified ultraviolet absorber UV-328 was added to 50 mL of water, the pH of the solution was adjusted to 9.5, and hydrolysis was performed with stirring for 8 h to prepare the hydrolyzed modified ultraviolet absorber UV-328;

[0076] S6. Preparation of composite modified Teflon paint: 0.25 g of Span-85, 0.7 g of sodium bicarbonate, 5 g of polytetrafluoroethylene emulsion were added to 200 mL of water to prepare an aqueous emulsion, heated to 77°C, stirred and mixed, 4 g of lauryl acrylate, 9 g of methyl methacrylate, 0.7 g of butyl acrylate, 3 g of modified composite molybdenum carbon ceramic powder, 0.7 g of hydrolyzed modified ultraviolet absorber UV-328 were added, stirred and mixed for 30 min, 0.0012 g of sodium persulfate was added, stirred and reacted for 8 h, filtered, discharged, and the composite modified Teflon paint was prepared.

[0077] Comparative Example 3

[0078] The difference compared with Example 3 is that step S3 is not performed.

[0079] The details are as follows:

[0080] S1. Preparation of molybdenum carbide / graphite / carbon fiber composite: 4 g of molybdenum carbide was ball milled for 1 h, then 1.5 g of expanded graphite and 0.7 g of carbon fiber were added, and plasma assisted ball milling was performed for 11 h, with the power parameters of the plasma being: discharge voltage 22 kV, discharge frequency 12 kHz, to obtain a composite;

[0081] S2. Carbon addition: The composite was carbonized under nitrogen protection using natural gas as the carbon source by chemical vapor deposition process, with the deposition temperature being 1100°C and the time being 48 h, to obtain a high-density composite;

[0082] S3. Oleic acid modification: 6 g of high-density composite was mixed with 3 g of oleic acid, and plasma assisted ball milling was performed for 20 h, with the power parameters of the plasma being: discharge voltage 22 kV, discharge frequency 12 kHz, to obtain a modified high-density composite;

[0083] S4. Modification of ultraviolet absorber UV-328: 0.9 g of ultraviolet absorber UV-328 was added to 50 mL of ethanol, 0.25 g of silane coupling agent KH570 was added, heated to 55°C, and stirred and reacted for 2.5 h to obtain modified ultraviolet absorber UV-328;

[0084] S5. Hydrolysis: 1 g of modified ultraviolet absorber UV-328 was added to 50 mL of water, the pH value of the solution was adjusted to 9.5, and the solution was stirred and hydrolyzed for 8 h to obtain hydrolyzed modified ultraviolet absorber UV-328;

[0085] S6. Preparation of composite modified Teflon paint: 0.25 g of Span-85, 0.7 g of sodium bicarbonate, 5 g of polytetrafluoroethylene emulsion were added to 200 mL of water to prepare an aqueous emulsion, heated to 77°C, stirred and mixed, 4 g of lauryl acrylate, 9 g of methyl methacrylate, 0.7 g of butyl acrylate, 3 g of modified high-density composite, 0.7 g of hydrolyzed modified ultraviolet absorber UV-328 were added, stirred and mixed for 30 min, 0.0012 g of sodium persulfate was added, stirred and reacted for 8 h, filtered, discharged, and the composite modified Teflon paint was prepared.

[0086] Comparative Example 4

[0087] Compared with Example 3, the difference is that step S6 is not performed.

[0088] The specific process is as follows:

[0089] S1. Preparation of molybdenum carbide / graphite / carbon fiber composite: 4 g of molybdenum carbide was ball milled for 1 h, then 1.5 g of expanded graphite and 0.7 g of carbon fiber were added, and plasma assisted ball milling was performed for 11 h, with the power parameters of the plasma being: discharge voltage 22 kV, discharge frequency 12 kHz, to obtain a composite;

[0090] S2. Carbon addition: the composite was carbonized by chemical vapor deposition process under nitrogen protection using natural gas as carbon source, the deposition temperature was 1100°C, and the time was 48 h, to obtain a high-density composite;

[0091] S3. Silicon infiltration: the high-density composite was subjected to melt silicon infiltration, crushed, and ball milled for 6 h to obtain a high-density composite molybdenum carbon ceramic material with a density of 2.33 g / cm 3 ;

[0092] S4. Oleic acid modification: 6 g of high-density composite molybdenum carbon ceramic powder was mixed with 3 g of oleic acid, and plasma assisted ball milling was performed for 20 h, with the power parameters of the plasma being: discharge voltage 22 kV, discharge frequency 12 kHz, to obtain modified high-density composite molybdenum carbon ceramic powder;

[0093] S5. Modification of ultraviolet absorber UV-328: 0.9 g of ultraviolet absorber UV-328 was added to 50 mL of ethanol, 0.25 g of silane coupling agent KH570 was added, heated to 55°C, and stirred and reacted for 2.5 h to obtain modified ultraviolet absorber UV-328;

[0094] S6. Preparation of composite modified Teflon coating: 0.25g of Span-85, 0.7g of sodium bicarbonate, 5g of polytetrafluoroethylene emulsion were added to 200mL of water to prepare an aqueous emulsion, heated to 77℃, stirred and mixed, 4g of lauryl acrylate, 9g of methyl methacrylate, 0.7g of butyl acrylate, 3g of modified high-density composite molybdenum carbon ceramic powder, 0.7g of modified ultraviolet absorber UV-328 were added, stirred and mixed for 30min, 0.0012g of sodium persulfate was added, stirred and reacted for 8h, filtered, discharged, and the composite modified Teflon coating was prepared.

[0095] Comparative Example 5

[0096] Compared with Example 3, the difference is that no hydrolysis modified ultraviolet absorber UV-328 is added in step S7.

[0097] Specifically as follows:

[0098] S1. Preparation of molybdenum carbide / graphite / carbon fiber composite: 4g of molybdenum carbide was ball milled for 1h, then 1.5g of expanded graphite and 0.7g of carbon fiber were added, and plasma assisted ball milling was performed for 11h, with the power parameters of the plasma being: discharge voltage 22kV, discharge frequency 12kHz, to obtain a composite;

[0099] S2. Carbon addition: the composite was carbonized under nitrogen protection by using natural gas as carbon source by chemical vapor deposition process, with the deposition temperature being 1100℃ and the time being 48h, to obtain a high-density composite;

[0100] S3. Silicon infiltration: the high-density composite was subjected to molten silicon infiltration, crushed, and ball milled for 6h to obtain a high-density molybdenum carbon ceramic material with a density of 2.33g / cm 3 ;

[0101] S4. Oleic acid modification: 6g of high-density composite molybdenum carbon ceramic powder was mixed with 3g of oleic acid, and plasma assisted ball milling was performed for 20h, with the power parameters of the plasma being: discharge voltage 22kV, discharge frequency 12kHz, to obtain modified high-density composite molybdenum carbon ceramic powder;

[0102] S5. Preparation of composite modified Teflon coating: 0.25g of Span-85, 0.7g of sodium bicarbonate, 5g of polytetrafluoroethylene emulsion were added to 200mL of water to prepare an aqueous emulsion, heated to 77℃, stirred and mixed, 4g of lauryl acrylate, 9g of methyl methacrylate, 0.7g of butyl acrylate, 3g of modified high-density composite molybdenum carbon ceramic powder, 0.7g of modified ultraviolet absorber UV-328 were added, stirred and mixed for 30min, 0.0012g of sodium persulfate was added, stirred and reacted for 8h, filtered, discharged, and the composite modified Teflon coating was prepared.

[0103] Test Example 1

[0104] The composite modified Teflon coating prepared in Examples 1-3 and Comparative Examples 1-5, water-dispersible organic pigment and thickening agent are mixed uniformly, and then stirred to a certain consistency, so as to obtain a printing paste, and a printing fabric is obtained by blade printing on a nylon cloth. The printed fabric is pre-baked at 80℃ for 5min, and then high-temperature baked at 170℃ for 3min to obtain a printing and dyeing fabric.

[0105] K / S value test: the K / S value of the printing and dyeing fabric is tested by using a UV-2600PC ultraviolet-visible spectrophotometer. The color depth of the printed fabric is compared by testing.

[0106] Water contact angle test: the water contact angle of the surface of the printing and dyeing fabric is tested by using a CA200 automatic optical contact angle measuring instrument.

[0107] Rubbing fastness test: the rubbing fastness test is tested by using a Y571B type rubbing fastness tester, and the test standard is GB / T3920-2008 "Textiles-Color fastness test-Rubbing fastness", then the printed fabric is rated by using "Gray sample card for rating staining".

[0108] Sunlight fastness test: the sunlight fastness test is tested by using a Q-UV-2000Q-SUN weathering tester. The test standard is GB / T 8427-2019 "Textiles-Color fastness test-Resistance to artificial light".

[0109] Soap washing fastness test: the test standard is GB / T 3921-2008 "Textiles-Color fastness test-Resistance to soaping".

[0110] Sweat fastness test: the test standard is GB / T 3922-2013 "Textiles-Color fastness test-Resistance to sweat".

[0111] Heat resistance test: the fabric is placed in a condition of 140℃ and humidity of 90RH%, and treated for 120h, and the dry rubbing fastness is tested.

[0112] The results are shown in Table 1.

[0113] Table 1

[0114] From the above table, it can be seen that the composite modified Teflon coating prepared in Examples 1-3 can obviously improve the rubbing resistance, washing resistance, sweat resistance and sunlight resistance of the fabric, the K / S value is high, and the water contact angle is improved.

[0115] The above only describes the preferred embodiments of the present application, and is not intended to limit the present application, and any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for preparing a composite modified Teflon coating, characterized in that, After the preparation of the molybdenum carbide / graphite / carbon fiber composite material, silicon infiltration, carbon increase, modification with oleic acid, mixing with ultraviolet absorber UV-328 modified by silane coupling agent, adding into polytetrafluoroethylene emulsion, adding acrylic monomer, polymerization reaction, the composite modified Teflon coating is prepared.

2. The production method according to claim 1, characterized by, The method comprises the following steps: S1. Preparation of molybdenum carbide / graphite / carbon fiber composite material: after ball milling of molybdenum carbide, expandable graphite and carbon fiber are added, and plasma assisted ball milling is performed to prepare a composite; S2. Carbon increase: the composite is carbon-increased by chemical vapor deposition process under nitrogen protection using natural gas as carbon source to obtain a high-density composite; S3. Silicon infiltration: the high-density composite is subjected to molten silicon infiltration, crushing, ball milling to obtain a high-density composite molybdenum carbon ceramic material; S4. Oleic acid modification: the high-density composite molybdenum carbon ceramic powder is mixed with oleic acid, and plasma assisted ball milling is performed to obtain modified high-density composite molybdenum carbon ceramic powder; S5. Modification of ultraviolet absorber UV-328: the ultraviolet absorber UV-328 is added into ethanol, and silane coupling agent KH570 is added, and heated and stirred to react to obtain modified ultraviolet absorber UV-328; S6. Hydrolysis: the modified ultraviolet absorber UV-328 is added into water, the pH value of the solution is adjusted, and stirring hydrolysis is performed to obtain hydrolyzed modified ultraviolet absorber UV-328; S7. Preparation of composite modified Teflon coating: emulsifier, pH buffer, polytetrafluoroethylene emulsion are prepared into an aqueous phase emulsion, heated and stirred to mix, long-chain alkyl acrylate, methyl methacrylate, butyl acrylate, modified high-density composite molybdenum carbon ceramic powder, hydrolyzed modified ultraviolet absorber UV-328 are added, stirred and mixed uniformly, initiator is added, stirred to react, filtered, discharged to obtain the composite modified Teflon coating.

3. The preparation method according to claim 2, characterized in that, The mass ratio of the molybdenum carbide, expandable graphite and carbon fiber in step S1 is 3-5:1-2:0.5-1, and the power parameters of the plasma are as follows: discharge voltage 20-24 kV and discharge frequency 10-15 kHz.

4. The preparation method according to claim 2, characterized in that, The carbon source of the chemical vapor deposition process in step S2 is natural gas or propane gas, the deposition temperature of the carburization is 1000-1200℃, and the time is 44-52h; the density of the composite molybdenum-carbon ceramic material in step S3 is 2.3-2.5g / cm 3 .

5. The preparation method according to claim 2, characterized in that, The mass ratio of the high-density composite molybdenum carbon ceramic powder and oleic acid in step S4 is 5-7:2-4, and the power parameters of the plasma are as follows: discharge voltage 20-24 kV and discharge frequency 10-15 kHz.

6. The preparation method according to claim 2, characterized in that, The mass ratio of the ultraviolet absorber UV-328 and silane coupling agent KH570 in step S5 is 8-10:2-3, the temperature of the heated stirring reaction is 50-60℃, and the time is 2-3 h.

7. The preparation method according to claim 2, characterized in that, The pH value of the solution in step S6 is adjusted to 9-10, and the stirring hydrolysis time is 7-10 h.

8. The preparation method according to claim 2, characterized in that, The mass ratio of the emulsifier, pH buffer, polytetrafluoroethylene emulsion, long-chain alkyl acrylate, methyl methacrylate, butyl acrylate, modified high-density composite molybdenum carbon ceramic powder, hydrolysis modified ultraviolet absorber UV-328 and initiator in step S7 is 0.2-0.3:0.5-1:4-6:3-5:8-10:0.5-1:2-4:0.5-1:0.001-0.0015, the emulsifier is at least one selected from Span-20, Span-40, Span-60, Span-80, Span-85, the pH buffer is sodium bicarbonate or sodium carbonate, the initiator is at least one selected from ammonium persulfate, potassium persulfate, sodium persulfate, the long-chain alkyl acrylate is at least one selected from 2-ethylhexyl acrylate, lauryl acrylate, the stirring reaction time is 7-10h, and the heating temperature is 75-80℃.

9. A composite modified Teflon coating prepared by the preparation method of any one of claims 1-8.

10. Use of the composite modified Teflon coating of claim 9 in fabric coating.

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