Water-resistant and stain-resistant coating composition and application thereof in wood floor

Abstract

The invention provides a water-resistant and stain-resistant coating composition and application thereof in a wood floor, and belongs to the technical field of coating compositions. The water-resistant and stain-resistant coating composition comprises polystyrene modified carbon nanotubes, an organic fluorine modified waterborne polyurethane emulsion and an auxiliary agent, the preparation method of the polystyrene modified carbon nanotube comprises a grafting step. The grafting method comprises the following steps: mixing aminated carbon nanotubes and carboxylated polystyrene in dichloromethane, adding a catalyst N, N '-dicyclohexylcarbodiimide solution, reacting at 50-60 DEG C for 6-8 hours, and after the reaction is finished, filtering, washing and drying to obtain polystyrene modified carbon nanotubes; the coating composition prepared by the invention is free of cracks and spalling under hammering, the strength of the coating is high, the measured water contact angle of the coating is 114.2-115.5 degrees, the stain resistance is 99.3%-99.9%, and the water resistance and stain resistance of the coating are high.

Description

Technical Field

[0001] The invention provides a water-resistant and anti-fouling coating composition and application thereof in a wooden floor, belonging to the technical field of coating compositions. Background Art

[0002] Wooden flooring refers to floors made of wood. If wooden flooring is in a humid environment during daily use, it is easy to absorb moisture and expand and deform. The movement or collision of furniture or other objects can easily cause scratches or wear on wooden flooring. Daily stains such as food residues, oil stains, dust, etc. are easy to adhere to the surface of wooden flooring, which is difficult to clean and affects the appearance and hygiene. In order to reduce damage to wooden flooring, it is necessary to coat the surface of wooden flooring with water-resistant and anti-fouling coating to improve its water-resistant and anti-fouling properties, thereby avoiding such situations.

[0003] Waterborne polyurethane has been widely used in the coatings industry because it is non-toxic, environmentally friendly, and has good low-temperature resistance, wear resistance and mechanical properties. However, the waterproof performance of waterborne polyurethane materials is not ideal. In order to improve this situation, the current commonly used strategy is to introduce strong hydrophobic units, such as fluorinated compounds, into waterborne polyurethane to improve the water resistance of the coating.

[0004] CN114479641A provides a fluorine-modified waterborne polyurethane waterproof coating. The method prepares a fluorine-modified waterborne polyurethane resin by using the fluorine-containing compound octafluoropentanol. Since the surface free energy of the introduced fluorine element is low, the fluorine-containing compound migrates to the surface during drying and film formation, thereby reducing the surface energy of the coating and helping the coating to form a super-hydrophobic surface, making it difficult for water molecules to spread and penetrate thereon. The prepared fluorine-modified waterborne polyurethane resin enhances the water resistance of the coating. However, the introduction of fluorine atoms affects the continuity of the polyurethane molecular chain, changes the cross-linking density between polyurethanes, and causes the strength of the coating to decrease. In addition, the change in the cross-linking density between polyurethanes reduces the compactness of the coating, increases the tiny pores in the coating, and reduces the anti-fouling performance of the coating. Summary of the invention

[0005] In view of the deficiencies in the prior art, the present invention provides a water-resistant and anti-fouling coating composition and its application in wooden floors. The coating composition has good water-resistant and anti-fouling properties and high strength.

[0006] In order to solve the above technical problems, the present invention adopts the following technical solutions: A water-resistant and anti-fouling coating composition, comprising polystyrene-modified carbon nanotubes, organic fluorine-modified waterborne polyurethane emulsion and an auxiliary agent; The mass ratio of the polystyrene modified carbon nanotubes, the organic fluorine modified aqueous polyurethane emulsion and the auxiliary agent is 20-25:95-105:15-20; The auxiliary agent includes a thickener and a defoamer, and the mass ratio of the thickener to the defoamer is 1:0.9-1.1; The thickener is ethylene glycol distearate; The defoaming agent is ethylene oxide.

[0007] The method for preparing polystyrene-modified carbon nanotubes comprises the steps of carbon nanotube amination, polystyrene carboxylation and grafting; The method for aminating carbon nanotubes comprises: adding carbon nanotubes to a sulfuric acid solution, reacting at a stirring speed of 300-500 r / min for 2-3 hours at room temperature, filtering, washing and drying after the reaction to obtain acid-treated carbon nanotubes, adding the acid-treated carbon nanotubes to N,N-dimethylformamide, adding ethylenediamine, controlling the reaction temperature to 70-80° C., reacting at a stirring speed of 400-500 r / min for 2-3 hours, filtering, washing and drying after the reaction to obtain aminated carbon nanotubes; The mass concentration of the sulfuric acid solution is 60-70%; The mass ratio of the carbon nanotubes to the sulfuric acid solution is 1:12-15; The mass ratio of the acid-treated carbon nanotubes, N,N-dimethylformamide and ethylenediamine is 1:60-70:8-10.

[0008] The method for carboxylating polystyrene comprises adding polystyrene and maleic anhydride to toluene, adding azobisisobutyronitrile as a free radical initiator, controlling the reaction temperature to be 110-120° C., reacting for 2-3 hours at a stirring speed of 500-600 r / min, and after the reaction is completed, precipitating, filtering, washing and drying to obtain carboxylated polystyrene; The molecular weight of the polystyrene is 8-10w; The mass ratio of the polystyrene, maleic anhydride, toluene and azobisisobutyronitrile is 1:0.4-0.6:50-60:0.04-0.06.

[0009] The grafting method comprises mixing aminated carbon nanotubes and carboxylated polystyrene in dichloromethane, adding a catalyst N,N'-dicyclohexylcarbodiimide solution, controlling the reaction temperature to 50-60°C, reacting at a stirring speed of 400-500 r / min for 6-8 hours, and filtering, washing and drying after the reaction to obtain polystyrene-modified carbon nanotubes; The mass ratio of the aminated carbon nanotubes, carboxylated polystyrene, dichloromethane and N,N'-dicyclohexylcarbodiimide solution is 1:3-5:70-80:1-2; The mass concentration of the N,N'-dicyclohexylcarbodiimide solution is 5-10%.

[0010] The method for preparing the organic fluorine-modified aqueous polyurethane emulsion comprises the steps of preparing a polyurethane prepolymer and surface modification; The method for preparing the polyurethane prepolymer comprises adding polycarbonate diol into a reaction container containing toluene diisocyanate solution, adding stannous octoate as a catalyst, controlling the reaction temperature to be 70-80° C., and the reaction time to be 4-5 hours. After the reaction is completed, the polyurethane prepolymer is generated. The mass ratio of the polycarbonate diol, toluene diisocyanate solution and stannous octoate is 1:0.9-1.1:0.03-0.05; The mass concentration of the toluene diisocyanate solution is 20-30%.

[0011] The surface modification method comprises the following steps: adding a polyurethane prepolymer to a reaction container containing deionized water, mixing the mixture evenly, adding a perfluorobutyl ethyl acrylate solution and an ammonium persulfate solution to the container, reacting the mixture under nitrogen protection, controlling the reaction temperature to be 60-70° C., reacting the mixture at a stirring speed of 600-700 r / min for 3-4 hours, and filtering and washing the mixture after the reaction to obtain an organic fluorine-modified waterborne polyurethane emulsion. The mass concentration of the perfluorobutyl ethyl acrylate solution is 5-10%, and the mass concentration of the ammonium persulfate solution is 30-40%; The mass ratio of the polyurethane prepolymer, deionized water, perfluorobutyl ethyl acrylate solution and ammonium persulfate solution is 100:70-80:20-30:1-2.

[0012] The preparation method of the water-resistant and antifouling coating composition comprises the following steps: adding polystyrene-modified carbon nanotubes, organic fluorine-modified waterborne polyurethane emulsion and auxiliary agents into a reaction container, stirring at a rotation speed of 300-500 r / min for 1-2 hours, and obtaining the water-resistant and antifouling coating composition.

[0013] Compared with the prior art, the present invention has achieved the following beneficial effects: 1. The surface of the modified carbon nanotubes will carry polystyrene, which reduces the direct contact between the carbon nanotubes, thereby reducing the aggregation between the carbon nanotubes, making the distribution of the carbon nanotubes in the solution more uniform, thereby improving the dispersibility of the carbon nanotubes in the coating, and being able to more effectively fill the tiny pores in the coating, thereby improving the overall density of the coating, reducing the path for moisture and stains to penetrate into the coating, thereby improving the anti-fouling performance of the coating. The coating composition prepared by the present invention is applied to the upper surface of the wooden floor, and the water contact angle of the coating is measured to be 114.2°-115.5°, and the stain resistance is 99.3%-99.9%. The coating has strong water and stain resistance.

[0014] 2. The modified carbon nanotubes have extremely high mechanical strength and can significantly improve the hardness and impact strength of the coating. The coating composition prepared by the present invention is applied to the upper surface of the wooden floor. The hardness of the coating is measured to be 4H. There is no cracking or peeling under hammering, and the impact resistance is 58cm-61cm. The strength of the coating is high. DETAILED DESCRIPTION

[0015] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, the specific implementation methods of the present invention are now described. Example 1

[0016] A water-resistant and anti-fouling coating composition, comprising polystyrene-modified carbon nanotubes, organic fluorine-modified waterborne polyurethane emulsion and an auxiliary agent; The mass ratio of the polystyrene modified carbon nanotubes, the organic fluorine modified aqueous polyurethane emulsion and the auxiliary agent is 23:100:18; The auxiliary agent includes a thickener and a defoamer, and the mass ratio of the thickener to the defoamer is 1:1; The thickener is ethylene glycol distearate; The defoaming agent is ethylene oxide.

[0017] The preparation method of the polystyrene modified carbon nanotubes is as follows: (1) Amination of carbon nanotubes Dispersing carbon nanotubes in a sulfuric acid solution, reacting at room temperature at a speed of 400 r / min for 2.5 hours, filtering, washing and drying after the reaction to obtain acid-treated carbon nanotubes, adding the acid-treated carbon nanotubes to N,N-dimethylformamide, adding ethylenediamine, controlling the reaction temperature to 75°C, reacting at a stirring speed of 450 r / min for 2.5 hours, filtering, washing and drying after the reaction to obtain aminated carbon nanotubes; The mass concentration of the sulfuric acid solution is 65%; The mass ratio of the carbon nanotubes to the sulfuric acid solution is 1:13; The mass ratio of the acid-treated carbon nanotubes, N,N-dimethylformamide and ethylenediamine is 1:65:9.

[0018] (2) Carboxylation of polystyrene Add polystyrene and maleic anhydride to toluene, add azobisisobutyronitrile as a free radical initiator, control the reaction temperature to 115°C, react for 2.5 hours at a stirring speed of 550 r / min, and after the reaction is completed, precipitate, filter, wash and dry to obtain carboxylated polystyrene; The molecular weight of the polystyrene is 9w; The mass ratio of the polystyrene, maleic anhydride, toluene and azobisisobutyronitrile is 1:0.5:55:0.05.

[0019] (3) Grafting The aminated carbon nanotubes and the carboxylated polystyrene were mixed in dichloromethane, a catalyst N,N'-dicyclohexylcarbodiimide solution was added, the reaction temperature was controlled to be 55°C, and the reaction was carried out at a stirring speed of 450 r / min for 7 hours. After the reaction was completed, the polystyrene-modified carbon nanotubes were obtained by filtering, washing and drying. The mass ratio of the aminated carbon nanotubes, carboxylated polystyrene, dichloromethane and N,N'-dicyclohexylcarbodiimide solution is 1:4:75:1.5; The mass concentration of the N,N'-dicyclohexylcarbodiimide solution is 7.5%.

[0020] The preparation method of the organic fluorine-modified aqueous polyurethane emulsion is as follows: (1) Preparation of polyurethane prepolymer Add polycarbonate diol into a reaction container containing toluene diisocyanate solution, add stannous octoate catalyst, control the reaction temperature to 75°C, the reaction time to 4.5h, and after the reaction is completed, generate a polyurethane prepolymer; The mass ratio of the polycarbonate diol, toluene diisocyanate solution and stannous octoate is 1:1:0.04; The mass concentration of the toluene diisocyanate solution is 25%.

[0021] (2) Surface modification The polyurethane prepolymer is added to a reaction container containing deionized water, mixed evenly, and a perfluorobutyl ethyl acrylate solution and an ammonium persulfate solution are added to the container, and the reaction is carried out under nitrogen protection, the reaction temperature is controlled to be 65°C, and the reaction is carried out at a stirring speed of 650r / min for 3.5h. After the reaction is completed, the organic fluorine-modified waterborne polyurethane emulsion is obtained by filtering and washing. The mass concentration of the perfluorobutyl ethyl acrylate solution is 7.5%, and the mass concentration of the ammonium persulfate solution is 35%; The mass ratio of the polyurethane prepolymer, deionized water, perfluorobutyl ethyl acrylate solution and ammonium persulfate solution is 100:75:25:1.5.

[0022] The preparation method of the water-resistant and antifouling coating composition comprises the following steps: adding polystyrene-modified carbon nanotubes, organic fluorine-modified waterborne polyurethane emulsion and auxiliary agents into a reaction container, stirring at a rotation speed of 400 r / min for 1.5 hours, and obtaining the water-resistant and antifouling coating composition. Example 2

[0023] A water-resistant and anti-fouling coating composition, comprising polystyrene-modified carbon nanotubes, organic fluorine-modified waterborne polyurethane emulsion and an auxiliary agent; The mass ratio of the polystyrene modified carbon nanotubes, the organic fluorine modified aqueous polyurethane emulsion and the auxiliary agent is 20:95:15; The auxiliary agent includes a thickener and a defoamer, and the mass ratio of the thickener to the defoamer is 1:0.9; The thickener is ethylene glycol distearate; The defoaming agent is ethylene oxide.

[0024] The preparation method of the polystyrene modified carbon nanotubes is as follows: (1) Amination of carbon nanotubes Dispersing carbon nanotubes in a sulfuric acid solution, reacting at room temperature at a speed of 300 r / min for 2 hours, filtering, washing and drying after the reaction to obtain acid-treated carbon nanotubes, adding the acid-treated carbon nanotubes to N,N-dimethylformamide, adding ethylenediamine, controlling the reaction temperature to 70°C, reacting at a stirring speed of 400 r / min for 2 hours, filtering, washing and drying after the reaction to obtain aminated carbon nanotubes; The mass concentration of the sulfuric acid solution is 60%; The mass ratio of the carbon nanotubes to the sulfuric acid solution is 1:12; The mass ratio of the acid-treated carbon nanotubes, N,N-dimethylformamide and ethylenediamine is 1:60:8.

[0025] (2) Carboxylation of polystyrene Add polystyrene and maleic anhydride to toluene, add azobisisobutyronitrile as a free radical initiator, control the reaction temperature to 110°C, react for 2 hours at a stirring speed of 500 r / min, and after the reaction is completed, precipitate, filter, wash and dry to obtain carboxylated polystyrene; The molecular weight of the polystyrene is 8w; The mass ratio of the polystyrene, maleic anhydride, toluene and azobisisobutyronitrile is 1:0.4:50:0.04.

[0026] (3) Grafting The aminated carbon nanotubes and the carboxylated polystyrene were mixed in dichloromethane, a catalyst N,N'-dicyclohexylcarbodiimide solution was added, the reaction temperature was controlled to be 50°C, and the reaction was carried out at a stirring speed of 400 r / min for 6 hours. After the reaction was completed, the polystyrene-modified carbon nanotubes were obtained by filtering, washing and drying. The mass ratio of the aminated carbon nanotubes, carboxylated polystyrene, dichloromethane and N,N'-dicyclohexylcarbodiimide solution is 1:3:70:1; The mass concentration of the N,N'-dicyclohexylcarbodiimide solution is 5%.

[0027] The preparation method of the organic fluorine-modified aqueous polyurethane emulsion is as follows: (1) Preparation of polyurethane prepolymer Add polycarbonate diol into a reaction container containing toluene diisocyanate solution, add stannous octoate catalyst, control the reaction temperature to 70°C, the reaction time to 4 hours, and after the reaction is completed, generate a polyurethane prepolymer; The mass ratio of the polycarbonate diol, toluene diisocyanate solution and stannous octoate is 1:0.9:0.03; The mass concentration of the toluene diisocyanate solution is 20%.

[0028] (2) Surface modification The polyurethane prepolymer is added to a reaction container containing deionized water, mixed evenly, and a perfluorobutyl ethyl acrylate solution and an ammonium persulfate solution are added to the container, and the reaction is carried out under nitrogen protection, the reaction temperature is controlled to be 60° C., and the reaction is carried out at a stirring speed of 600 r / min for 3 hours. After the reaction is completed, the organic fluorine-modified waterborne polyurethane emulsion is obtained by filtering and washing. The mass concentration of the perfluorobutyl ethyl acrylate solution is 5%, and the mass concentration of the ammonium persulfate solution is 30%; The mass ratio of the polyurethane prepolymer, deionized water, perfluorobutyl ethyl acrylate solution and ammonium persulfate solution is 100:70:20:1.

[0029] The preparation method of the water-resistant and antifouling coating composition comprises the following steps: adding polystyrene-modified carbon nanotubes, organic fluorine-modified waterborne polyurethane emulsion and auxiliary agents into a reaction container, stirring at a rotation speed of 300 r / min for 1 hour, and obtaining the water-resistant and antifouling coating composition. Example 3

[0030] A water-resistant and anti-fouling coating composition, comprising polystyrene-modified carbon nanotubes, organic fluorine-modified waterborne polyurethane emulsion and an auxiliary agent; The mass ratio of the polystyrene modified carbon nanotubes, the organic fluorine modified aqueous polyurethane emulsion and the auxiliary agent is 25:105:20; The auxiliary agent includes a thickener and a defoamer, and the mass ratio of the thickener to the defoamer is 1:1.1; The thickener is ethylene glycol distearate; The defoaming agent is ethylene oxide.

[0031] The preparation method of the polystyrene modified carbon nanotubes is as follows: (1) Amination of carbon nanotubes Dispersing carbon nanotubes in a sulfuric acid solution, reacting at room temperature at a speed of 500 r / min for 3 hours, filtering, washing and drying after the reaction to obtain acid-treated carbon nanotubes, adding the acid-treated carbon nanotubes to N,N-dimethylformamide, adding ethylenediamine, controlling the reaction temperature to 80°C, reacting at a stirring speed of 500 r / min for 3 hours, filtering, washing and drying after the reaction to obtain aminated carbon nanotubes; The mass concentration of the sulfuric acid solution is 70%; The mass ratio of the carbon nanotubes to the sulfuric acid solution is 1:15; The mass ratio of the acid-treated carbon nanotubes, N,N-dimethylformamide and ethylenediamine is 1:70:10.

[0032] (2) Carboxylation of polystyrene Add polystyrene and maleic anhydride to toluene, add azobisisobutyronitrile as a free radical initiator, control the reaction temperature to 120°C, react for 3 hours at a stirring speed of 600 r / min, and after the reaction is completed, precipitate, filter, wash and dry to obtain carboxylated polystyrene; The molecular weight of the polystyrene is 10w; The mass ratio of the polystyrene, maleic anhydride, toluene and azobisisobutyronitrile is 1:0.6:60:0.06.

[0033] (3) Grafting The aminated carbon nanotubes and the carboxylated polystyrene were mixed in dichloromethane, a catalyst N,N'-dicyclohexylcarbodiimide solution was added, the reaction temperature was controlled to be 60°C, and the reaction was carried out at a stirring speed of 500 r / min for 8 hours. After the reaction was completed, the polystyrene-modified carbon nanotubes were obtained by filtering, washing and drying. The mass ratio of the aminated carbon nanotubes, carboxylated polystyrene, dichloromethane and N,N'-dicyclohexylcarbodiimide solution is 1:5:80:2; The mass concentration of the N,N'-dicyclohexylcarbodiimide solution is 10%.

[0034] The preparation method of the organic fluorine-modified aqueous polyurethane emulsion is as follows: (1) Preparation of polyurethane prepolymer Add polycarbonate diol into a reaction container containing toluene diisocyanate solution, add stannous octoate catalyst, control the reaction temperature to 80°C, the reaction time to 5 hours, and after the reaction is completed, generate a polyurethane prepolymer; The mass ratio of the polycarbonate diol, toluene diisocyanate solution and stannous octoate is 1:1.1:0.05; The mass concentration of the toluene diisocyanate solution is 30%.

[0035] (2) Surface modification The polyurethane prepolymer is added to a reaction container containing deionized water, mixed evenly, and a perfluorobutyl ethyl acrylate solution and an ammonium persulfate solution are added to the container, and the reaction is carried out under nitrogen protection, the reaction temperature is controlled to be 70° C., and the reaction is carried out at a stirring speed of 700 r / min for 4 hours. After the reaction is completed, the organic fluorine-modified waterborne polyurethane emulsion is obtained by filtering and washing. The mass concentration of the perfluorobutyl ethyl acrylate solution is 10%, and the mass concentration of the ammonium persulfate solution is 40%; The mass ratio of the polyurethane prepolymer, deionized water, perfluorobutyl ethyl acrylate solution and ammonium persulfate solution is 100:80:30:2.

[0036] The preparation method of the water-resistant and antifouling coating composition comprises the following steps: adding polystyrene-modified carbon nanotubes, organic fluorine-modified waterborne polyurethane emulsion and auxiliary agents into a reaction container, stirring at a rotation speed of 500 r / min for 2 hours, and obtaining the water-resistant and antifouling coating composition.

[0037] Comparative Example 1 Based on Example 1, the change is that the carbon nanotubes are not modified, and in the preparation of a water-resistant and anti-fouling coating composition, ordinary carbon nanotubes are used instead of polystyrene-modified carbon nanotubes, and the other operations are the same.

[0038] The water-resistant and antifouling coating compositions prepared in Examples 1-3 and Comparative Example 1 were respectively applied to the upper surface of the wooden floor, and then dried with hot air at 100°C for 20 minutes. The coating film thickness after curing was 100 μm, thereby obtaining a wooden floor coated with the water-resistant and antifouling coating composition.

[0039] Test Example 1 Hardness Performance Test of Coating Composition According to the standard GB6739-86 "Coating Hardness Pencil Hardness Method", the wooden floor coated with the water-resistant and anti-fouling coating composition was tested. The test piece was fixed on a horizontal plane, and a sharpened pencil was held at a 45-degree angle to the coating. The pencil was pushed forward at a speed of about 1 mm per second. Starting from the hardest pencil, five 3mm marks were made for each level of pencil until a pencil with five marks that did not damage the coating was found. The hardness of this pencil represents the pencil hardness of the tested coating. The test results are shown in Table 1: Table 1 Hardness test results of coatings

[0040] Test Example 2 Impact strength performance test of coating composition Referring to "GB / T 1732-1993 Determination Method for Impact Resistance of Paint Films", place the prepared test panel with the paint film facing up flat on the anvil of the impact tester. The distance from the impacted part of the test panel to the edge shall be not less than 15 mm, and the distance between each impact point shall be not less than 15 mm. Use a 1000 g falling weight, let the falling weight freely fall from a height of 50 cm to impact the test panel, record the data of each falling weight, and the test results are shown in Table 2: Table 2 Test Results of Impact Resistance Strength of Coating

[0041] Use a 1000 g falling weight to freely fall and let it hit the paint film. Carefully observe whether there is any damage to the paint film at the collision point. If not, change the position and increase the height. Start from 40 cm and increase by 2 cm each time until cracks or damage appear on the paint film. Record the height (cm) at this time. The test results are shown in Table 3: Table 3 Test Results of Impact Resistance Strength of Coating

[0042] Test Example 3 Test of Water and Stain Resistance Performance of Coating Composition According to the specification GB / T 30693-2014, test the water contact angle of the prepared paint film with a water droplet projection contact angle measuring instrument. Hang a water droplet at the end of the needle, raise the specimen stage to make the specimen surface contact the hanging water droplet, and then move the specimen away to complete the transfer of the water droplet. Use the measuring instrument to record the results each time. The test results are shown in Table 4: Table 4 Test Results of Water Contact Angle of Coating

[0043] According to the specification GB / T 9780-2013, test the stain resistance performance of the prepared paint film. Use a 2B pencil to draw four test areas, each test area with a width of (25±2) mm and an interval of (20±2) mm. Test the initial reflectance coefficient of the paint film in the test area with a reflectometer and record it as Y0. Cover the test area with a gauze, use blue-black ink as the liquid stain for the experiment, suck about 3 mL of the liquid stain with a pipette, drop it on the gauze in the test area, fully soak the gauze, let it stand for 2 h, then remove the gauze, clean the paint film stain in the test area, and then test the reflectance coefficient of the paint film in the test area at this time with a reflectometer and record it as Y1. The ratio of the reflectance coefficient after the test to the initial reflectance coefficient is the stain resistance, and the stain resistance formula is X = Y1 / Y0×100‰; In the above formula, X is the stain resistance of the paint film of the coating to the stain in each test area. The greater the stain resistance, the stronger the stain resistance performance of the paint film; The test results are shown in Table 5: Table 5 Test Results of Stain Resistance Performance of Coating

[0044] It can be seen from Table 1, Table 2 and Table 3 that the hardness of the coating prepared in Examples 1-3 is 4H, which is high. The impact resistance of the coating can reach 58-61cm. The strength of the coating is improved by modifying the carbon nanotubes. Comparative Example 1 uses ordinary carbon nanotubes as filler, and the prepared coating has fine cracks and poor strength.

[0045] It can be seen from Table 4 that the water contact angles of the coatings prepared in Examples 1-3 and Comparative Example 1 are high, and the coatings have good water resistance; it can be seen from Table 5 that the stain resistance of the coatings prepared in Examples 1-3 reaches 99.3-99.9%, and the coatings have strong stain resistance. Comparative Example 1 uses ordinary carbon nanotubes as fillers, and the stain resistance of the prepared coating is 80.3%, and the coating has weak stain resistance.

[0046] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention is described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A water-resistant and antifouling coating composition, characterized in that: The water-resistant and anti-fouling coating composition comprises polystyrene-modified carbon nanotubes, organic fluorine-modified waterborne polyurethane emulsion and additives; The method for preparing polystyrene-modified carbon nanotubes comprises the steps of carbon nanotube amination, polystyrene carboxylation and grafting; The method for aminating carbon nanotubes is as follows: adding the acid-treated carbon nanotubes to N,N-dimethylformamide, adding ethylenediamine, reacting at 70-80° C. for 2-3 hours, filtering, washing, and drying after the reaction to obtain aminated carbon nanotubes; The method for carboxylating polystyrene comprises adding polystyrene and maleic anhydride into toluene, adding azobisisobutyronitrile as a free radical initiator, reacting at 110-120° C. for 2-3 hours, and after the reaction, precipitating, filtering, washing and drying to obtain carboxylated polystyrene; The grafting method comprises mixing aminated carbon nanotubes and carboxylated polystyrene in dichloromethane, adding a catalyst N,N'-dicyclohexylcarbodiimide solution, reacting at 50-60°C for 6-8h, and filtering, washing and drying after the reaction to obtain polystyrene modified carbon nanotubes.

2. A water-resistant and antifouling coating composition according to claim 1, characterized in that: In the method for amination of carbon nanotubes, the mass ratio of the acid-treated carbon nanotubes, N,N-dimethylformamide and ethylenediamine is 1:60-70:8-10; In the method for carboxylating polystyrene, the mass ratio of polystyrene, maleic anhydride, toluene and azobisisobutyronitrile is 1:0.4-0.6:50-60:0.04-0.06; The molecular weight of the polystyrene is 8-10w; In the grafting method, the mass ratio of the aminated carbon nanotubes, the carboxylated polystyrene, the dichloromethane and the N,N'-dicyclohexylcarbodiimide solution is 1:3-5:70-80:1-2; The mass concentration of the N,N'-dicyclohexylcarbodiimide solution is 5-10%.

3. A water-resistant and antifouling coating composition according to claim 1, characterized in that: The acid-treated carbon nanotubes are prepared by adding the carbon nanotubes to a sulfuric acid solution, reacting at room temperature for 2-3 hours, and filtering, washing and drying after the reaction to obtain the acid-treated carbon nanotubes; The mass concentration of the sulfuric acid solution is 60-70%; The mass ratio of the carbon nanotubes to the sulfuric acid solution is 1:12-15.

4. A water-resistant and antifouling coating composition according to claim 1, characterized in that: The method for preparing the organic fluorine-modified aqueous polyurethane emulsion comprises the steps of preparing a polyurethane prepolymer; The method for preparing the polyurethane prepolymer comprises adding polycarbonate diol into a reaction container containing toluene diisocyanate solution, adding stannous octoate as a catalyst, controlling the reaction temperature to be 70-80° C., and the reaction time to be 4-5 hours. After the reaction is completed, the polyurethane prepolymer is generated. The mass ratio of the polycarbonate diol, toluene diisocyanate solution and stannous octoate is 1:0.9-1.1:0.03-0.05; The mass concentration of the toluene diisocyanate solution is 20-30%.

5. A water-resistant and antifouling coating composition according to claim 1, characterized in that: The method for preparing the organic fluorine-modified aqueous polyurethane emulsion comprises a surface modification step; The surface modification method comprises adding a polyurethane prepolymer into deionized water, adding a perfluorobutyl ethyl acrylate solution and an ammonium persulfate solution, reacting under nitrogen protection at 60-70° C. for 3-4 hours, and filtering and washing after the reaction to obtain an organic fluorine-modified waterborne polyurethane emulsion; The mass ratio of the polyurethane prepolymer, deionized water, perfluorobutyl ethyl acrylate solution and ammonium persulfate solution is 100:70-80:20-30:1-2; The mass concentration of the perfluorobutyl ethyl acrylate solution is 5-10%, and the mass concentration of the ammonium persulfate solution is 30-40%.

6. A water-resistant and antifouling coating composition according to claim 1, characterized in that: The preparation method of the water-resistant and antifouling coating composition comprises the following steps: adding polystyrene-modified carbon nanotubes, organic fluorine-modified waterborne polyurethane emulsion and auxiliary agents into a reaction container, stirring at a rotation speed of 300-500 r / min for 1-2 hours, and obtaining the water-resistant and antifouling coating composition.

7. The water-resistant and antifouling coating composition according to claim 1, characterized in that: The mass ratio of the polystyrene modified carbon nanotubes, the organic fluorine modified aqueous polyurethane emulsion and the auxiliary agent is 20-25:95-105:15-20; The auxiliary agent includes a thickener and a defoamer, and the mass ratio of the thickener to the defoamer is 1:0.9-1.1; The thickener is ethylene glycol distearate; The defoaming agent is ethylene oxide.

8. Use of the water-resistant and antifouling coating composition according to any one of claims 1 to 7 in wooden floors.

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