A kind of waterborne polyurethane floor paint and preparation process thereof

Abstract

The invention discloses a waterborne polyurethane floor paint and a preparation process thereof, and relates to the technical field of floor paint. The waterborne polyurethane floor paint is prepared from the following components by weight: 60-75 parts of polyurethane resin, 15-20 parts of hydroxyethyl methacrylate, 3-15 parts of modified graphene oxide, 6-13 parts of hydroxyethyl cellulose, 15-25 parts of curing agent, 1-3 parts of dispersant, 0.5-2 parts of leveling agent, 0.5-1 parts of defoaming agent, 3-8 parts of pigment, and 10-25 parts of deionized water. The floor paint uses modified graphene oxide as a filler, which is mixed with polyurethane resin, hydroxyethyl methacrylate, and a curing agent in water, and is mutually penetrated and entangled to form a hydrogen-bonded or network-crosslinked blended polymer, which has better wear resistance and weather resistance, can protect the surface of a coated ground structure for a long time, and is more environmentally friendly than solvent-based floor paint.

Description

Technical Field

[0001] The invention relates to the technical field of floor paints, and in particular to a waterborne polyurethane floor paint and a preparation process thereof. Background Art

[0002] Floor paint is generally used for floor construction in factory workshops, laboratories and other environments. It has the advantages of being beautiful, wear-resistant, waterproof and anti-corrosive. According to the different functions of the components of floor paint, it can generally be divided into main film-forming substances, such as polyurethane resin and epoxy resin; secondary film-forming substances, such as pigments, fillers, etc.; and auxiliary film-forming substances, including plasticizers, defoamers, wetting agents, curing agents, etc. Floor paint can be mainly divided into anti-corrosion floor paint, anti-static floor paint, load-bearing floor paint, anti-slip floor paint, wear-resistant floor paint and other categories according to the different characteristics of its coating. Among them, wear-resistant floor paint has good bearing capacity and wear resistance, and is suitable for factory workshops and warehouses with load-bearing vehicles or towing processes.

[0003] At present, floor paint can be divided into solvent-based floor paint and water-based floor paint. Solvent-based floor paint has high requirements for substrate humidity and environmental humidity during construction. It contains a large amount of VOC in the paint. During use, it will emit a large amount of toxic substances, causing damage to the environment and human body. At the same time, its flame retardant and explosion-proof performance is poor, and there are certain safety hazards. Water-based floor paint does not have too many requirements for substrate and environmental humidity during construction, and its flame retardant and explosion-proof performance is good. It is safer in production, transportation, storage, construction and other environments, and because it does not add organic solvents, it is very friendly to the environment and human body. However, compared with solvent-based floor paint, water-based floor paint has the disadvantages of low film density and poor construction performance.

[0004] There are a lot of hydrogen bonds between the flexible molecular chains of polyurethane polymers. When subjected to external forces, the hydrogen bonds between the flexible molecular chains of polyurethane are destroyed; after most of the external force is consumed, the hydrogen bonds between the molecular chains of polyurethane are restored. Based on this outstanding "viscoelastic" characteristic, polyurethane floor coatings have significantly better wear resistance than epoxy floor coatings.

[0005] Chinese patent document CN107245263A discloses a waterproof and wear-resistant floor paint and a preparation method thereof, wherein the floor paint comprises the following components: waterborne polyurethane, polyvinyl alcohol, graphene oxide, sodium acrylate, hydroxymethyl cellulose, polyurethane curing agent, paraffin emulsion, filler, bactericide, defoamer, and pigment. The preparation method comprises: first preparing a bactericide, then weighing graphene oxide, and mixing it with waterborne polyurethane and polyvinyl alcohol after functional modification to prepare a graphene-modified polymer; then mixing sodium acrylate, hydroxymethyl cellulose, paraffin emulsion and defoamer with the graphene-modified polymer, adding a filler, adding a bactericide and a pigment to the mixture after shearing, and mixing and stirring to obtain the floor paint.

[0006] This invention enhances the mechanical properties of water-based floor paint by adding graphene oxide material. However, graphene oxide has a small specific surface area and is prone to agglomeration in the paint, which affects the reinforcement efficiency. At the same time, directly adding graphene oxide material to the floor paint matrix has little effect on improving the performance of the floor paint. Summary of the invention

[0007] In order to solve the shortcomings of the prior art, the purpose of the present invention is to provide a water-based polyurethane floor paint and a preparation process thereof, wherein modified graphene oxide is used as a filler, mixed with a polyurethane resin, hydroxyethyl methacrylate, and a curing agent in water, and a hydrogen-bonded or network-crosslinked polymer is formed through mutual penetration and entanglement, so that the reinforcing effect of the filler is fully exerted. The obtained floor paint has better wear resistance and weather resistance, can protect the surface of the coated ground structure for a long time, and is more environmentally friendly than solvent-based floor paint.

[0008] In order to achieve the above object, the present invention adopts the following technical solution:

[0009] A water-based polyurethane floor paint is prepared from the following components, measured in parts by weight: 60-75 parts of polyurethane resin, 15-20 parts of hydroxyethyl methacrylate, 3-15 parts of modified graphene oxide, 6-13 parts of hydroxyethyl cellulose, 15-25 parts of curing agent, 1-3 parts of dispersant, 0.5-2 parts of leveling agent, 0.5-1 part of defoaming agent, 3-8 parts of pigment and 10-25 parts of deionized water.

[0010] Preferably, the method for preparing the modified graphene oxide comprises the following steps:

[0011] (1) dispersing graphene oxide in a sulfuric acid / nitric acid mixture, stirring for reaction, centrifuging and washing the product to obtain carboxylated graphene oxide;

[0012] (2) dispersing the carboxylated graphene oxide in DMF, adding a catalyst and stirring at room temperature to activate the carboxyl group, adding 4,4'-dithiodiphenylamine, reacting in an oil bath, centrifuging and washing the product to obtain disulfide bond-containing graphene oxide;

[0013] (3) dispersing the disulfide bond-containing graphene oxide in isopropanol, uniformly dispersing by ultrasonication, then adding oleic acid chloride, stirring for reaction, filtering, washing, and drying the product to obtain modified graphene oxide.

[0014] Preferably, in step (1), the sulfuric acid concentration in the sulfuric acid / nitric acid mixture is 60-80wt%, the nitric acid concentration is 40-60wt%, and the volume ratio of sulfuric acid to nitric acid is 2-4:1.

[0015] Preferably, in step (1), the ratio of graphene oxide to sulfuric acid / nitric acid mixture is 10 g:100 mL, and the reaction conditions are stirring and reacting at 80-100° C. for 6-10 hours.

[0016] Preferably, in step (2), the mass ratio of carboxylated graphene oxide, catalyst and 4,4'-dithiodiphenylamine is 100:3-6:5-18.

[0017] Preferably, in step (2), the catalyst is a MES buffer prepared by mixing 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and N-hydroxysuccinimide, and the molar ratio of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride to N-hydroxysuccinimide is 1:1 to 2:1.

[0018] Preferably, in step (2), the activation time of the carboxyl group is 30 to 60 minutes, and the reaction conditions are oil bath reaction at 90 to 110° C. for 8 to 12 hours.

[0019] Preferably, in step (3), the usage ratio of disulfide bond-containing graphene oxide, oleic acid chloride and isopropanol is 10 g: 2-8 g: 100 mL.

[0020] Preferably, in step (3), the reaction conditions are 15-35° C. and stirring under nitrogen atmosphere for 3-7 hours.

[0021] Preferably, the curing agent is one or more of hexamethylene diisocyanate, toluene diisocyanate or isophorone diisocyanate.

[0022] The present invention also claims protection for a preparation process of the waterborne polyurethane floor paint, comprising the following steps: uniformly stirring and mixing polyurethane resin, hydroxyethyl methacrylate, hydroxyethyl cellulose and deionized water by weight, then adding a dispersant, a leveling agent, a defoaming agent, a pigment, and modified graphene oxide, dispersing them uniformly, and finally adding a curing agent and mixing them uniformly to obtain the waterborne polyurethane floor paint.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] 1) The present invention provides a water-based polyurethane floor paint, which uses modified graphene oxide as a filler, is mixed with a polyurethane resin, hydroxyethyl methacrylate, and a curing agent in water, and is mutually penetrated and entangled to form a hydrogen-bonded or network-crosslinked blended polymer, which gives full play to the reinforcing effect of the filler. The obtained floor paint has better wear resistance and weather resistance, can protect the surface of the coated ground structure for a long time, and is more environmentally friendly than solvent-based floor paint.

[0025] 2) The present invention provides a preparation process of waterborne polyurethane floor paint, firstly, carboxylating graphene oxide with a concentrated sulfuric acid / concentrated nitric acid mixture to expose more reactive sites on its surface, and then, under the action of a catalyst, introducing disulfide bonds and benzene rings into the surface of graphene oxide through the amidation reaction of the amino group in 4,4'-dithiodiphenylamine with the carboxyl group on the surface of carboxylated graphene oxide to obtain disulfide bond-containing graphene oxide, the rigid benzene ring can improve the impact strength and weather resistance of the paint film, the disulfide bond will break under stress to form a sulfur free radical, and then form a thiol group, the change process will release energy, prevent the paint film from further damage, thereby improving the mechanical properties of the floor paint, in addition, the disulfide bond can still be formed again after being destroyed by external force, which can give the coating a self-healing function; finally, through the amidation reaction of the amino group in the disulfide bond-containing graphene oxide with oleic acid chloride Through chemical reaction, long-chain oleate groups are grafted onto the surface of graphene oxide to obtain modified graphene oxide, which can effectively increase the flexibility of the polyurethane resin segment. When the floor paint is impacted by external force, the flexible oleate segment can increase the impact strength of the paint film through plastic deformation, and it can synergistically improve the mechanical properties of the polyurethane floor paint with the benzene ring and disulfide bond. After modification, graphene oxide can be evenly dispersed in the polyurethane resin matrix, effectively preventing the agglomeration of nano-inorganic materials, and forming a dense physical isolation layer in the paint film through chemical cross-linking and hydrogen bonding. Due to its special lamellar structure, it can shield tiny holes on the surface of the floor paint, thereby extending the path of corrosive media such as air on the surface, and has excellent shielding effect and maze effect, which can give water-based polyurethane floor paint excellent mechanical properties, wear resistance and excellent corrosion resistance. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solution and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with embodiments. Of course, the specific embodiments described here are only used to explain the present invention and are not used to limit the present invention.

[0027] Unless otherwise specified, the chemical reagents and materials in the present invention are purchased from commercial sources or synthesized from raw materials purchased from commercial sources.

[0028] The polyurethane resin is water-based polyurethane, Wanhua Chemical;

[0029] The leveling agent is 4100 digo;

[0030] The dispersant is SW-AD-F-053 Jiangsu Shisong;

[0031] The defoamer is XP-01 Chengdu Aodefu.

[0032] A preparation process of a waterborne polyurethane floor paint comprises the following steps:

[0033] (1) dispersing 10 g of graphene oxide into 100 mL of a sulfuric acid / nitric acid mixture (sulfuric acid concentration is 60-80 wt %, nitric acid concentration is 40-60 wt %, and the volume ratio of sulfuric acid to nitric acid is 2-4:1), stirring and reacting at 80-100° C. for 6-10 h, centrifuging and washing the product to obtain carboxylated graphene oxide;

[0034] (2) 10 g of carboxylated graphene oxide was dispersed in 100 mL of DMF, and then 0.3-0.6 g of a catalyst (MES buffer prepared by mixing 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and N-hydroxysuccinimide, the molar ratio of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride to N-hydroxysuccinimide was 1:1-2:1) was added, and the carboxyl groups were activated at room temperature for 30-60 min, and then 0.5-1.8 g of 4,4'-dithiodiphenylamine was added, and the reaction was carried out in an oil bath at 90-110° C. for 8-12 h. The product was centrifuged and washed to obtain graphene oxide containing disulfide bonds;

[0035] (3) dispersing 10 g of disulfide bond-containing graphene oxide into 100 mL of isopropanol, uniformly dispersing by ultrasonication, then adding 2 to 8 g of oleic acid chloride, stirring and reacting at 15 to 35 ° C. under a nitrogen atmosphere for 3 to 7 hours, filtering, washing, and drying the product to obtain modified graphene oxide;

[0036] (4) 60-75 parts of polyurethane resin, 15-20 parts of hydroxyethyl methacrylate, 6-13 parts of hydroxyethyl cellulose and 10-25 parts of deionized water are stirred and mixed uniformly, and then 1-3 parts of dispersant, 0.5-2 parts of leveling agent, 0.5-1 part of defoaming agent, 3-8 parts of pigment, and 3-15 parts of modified graphene oxide are added and dispersed uniformly, and finally 15-25 parts of curing agent are added and mixed uniformly to obtain the waterborne polyurethane floor paint.

[0037] The present invention will be further described below through specific embodiments.

[0038] Example 1

[0039] A preparation process of a waterborne polyurethane floor paint comprises the following steps:

[0040] (1) dispersing 10 g of graphene oxide into 100 mL of a sulfuric acid / nitric acid mixture (sulfuric acid concentration of 80 wt %, nitric acid concentration of 60 wt %, volume ratio of sulfuric acid to nitric acid of 4:1), stirring and reacting at 100° C. for 6 h, centrifuging and washing the product to obtain carboxylated graphene oxide;

[0041] (2) 10 g of carboxylated graphene oxide was dispersed in 100 mL of DMF, and then 0.6 g of catalyst (MES buffer prepared by mixing 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and N-hydroxysuccinimide, the molar ratio of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride to N-hydroxysuccinimide was 2:1) was added, and the carboxyl groups were activated at room temperature for 60 min, and then 1.8 g of 4,4'-dithiodiphenylamine was added, and the reaction was carried out in an oil bath at 110°C for 8 h. The product was centrifuged and washed to obtain graphene oxide containing disulfide bonds;

[0042] (3) Dispersing 10 g of disulfide bond-containing graphene oxide in 100 mL of isopropanol, uniformly dispersing by ultrasonication, then adding 8 g of oleic acid chloride, stirring and reacting at 35 ° C. under a nitrogen atmosphere for 3 h, filtering, washing, and drying the product to obtain modified graphene oxide;

[0043] (4) 70 g of polyurethane resin, 18 g of hydroxyethyl methacrylate, 10 g of hydroxyethyl cellulose and 18 g of deionized water were stirred and mixed evenly, and then 2 g of dispersant, 1.5 g of leveling agent, 0.8 g of defoaming agent, 5 g of pigment and 15 g of modified graphene oxide were added and dispersed evenly, and finally 20 g of curing agent was added and mixed evenly to obtain the waterborne polyurethane floor paint.

[0044] Example 2

[0045] A preparation process of a waterborne polyurethane floor paint comprises the following steps:

[0046] (1) dispersing 10 g of graphene oxide into 100 mL of a sulfuric acid / nitric acid mixture (sulfuric acid concentration of 80 wt %, nitric acid concentration of 60 wt %, volume ratio of sulfuric acid to nitric acid of 3:1), stirring and reacting at 90° C. for 8 h, centrifuging and washing the product to obtain carboxylated graphene oxide;

[0047] (2) 10 g of carboxylated graphene oxide was dispersed in 100 mL of DMF, and then 0.5 g of catalyst (MES buffer prepared by mixing 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and N-hydroxysuccinimide, the molar ratio of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride to N-hydroxysuccinimide was 1:1) was added, and the carboxyl groups were activated at room temperature for 45 min, and then 1.2 g of 4,4'-dithiodiphenylamine was added, and the mixture was reacted in an oil bath at 100 ° C for 10 h. The product was centrifuged and washed to obtain graphene oxide containing disulfide bonds;

[0048] (3) Dispersing 10 g of disulfide bond-containing graphene oxide in 100 mL of isopropanol, uniformly dispersing by ultrasonication, then adding 5 g of oleic acid chloride, stirring and reacting at 20 ° C. under a nitrogen atmosphere for 5 h, filtering, washing, and drying the product to obtain modified graphene oxide;

[0049] (4) 70 g of polyurethane resin, 18 g of hydroxyethyl methacrylate, 10 g of hydroxyethyl cellulose and 18 g of deionized water were stirred and mixed evenly, and then 2 g of dispersant, 1.5 g of leveling agent, 0.8 g of defoaming agent, 5 g of pigment and 12 g of modified graphene oxide were added and dispersed evenly, and finally 20 g of curing agent was added and mixed evenly to obtain the waterborne polyurethane floor paint.

[0050] Example 3

[0051] A preparation process of a waterborne polyurethane floor paint comprises the following steps:

[0052] (1) dispersing 10 g of graphene oxide into 100 mL of a sulfuric acid / nitric acid mixture (sulfuric acid concentration of 80 wt %, nitric acid concentration of 60 wt %, volume ratio of sulfuric acid to nitric acid of 2:1), stirring and reacting at 80° C. for 10 h, centrifuging and washing the product to obtain carboxylated graphene oxide;

[0053] (2) 10 g of carboxylated graphene oxide was dispersed in 100 mL of DMF, and then 0.3 g of catalyst (MES buffer prepared by mixing 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and N-hydroxysuccinimide, the molar ratio of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride to N-hydroxysuccinimide was 1:1) was added, and the carboxyl groups were activated at room temperature for 30 min, and then 0.5 g of 4,4'-dithiodiphenylamine was added, and the reaction was carried out in an oil bath at 90°C for 12 h. The product was centrifuged and washed to obtain graphene oxide containing disulfide bonds;

[0054] (3) Dispersing 10 g of disulfide bond-containing graphene oxide in 100 mL of isopropanol, uniformly dispersing by ultrasonication, then adding 2 g of oleic acid chloride, stirring and reacting for 7 h at 15 ° C. under a nitrogen atmosphere, filtering, washing, and drying the product to obtain modified graphene oxide;

[0055] (4) 70 g of polyurethane resin, 18 g of hydroxyethyl methacrylate, 10 g of hydroxyethyl cellulose and 18 g of deionized water were stirred and mixed evenly, and then 2 g of dispersant, 1.5 g of leveling agent, 0.8 g of defoaming agent, 5 g of pigment and 9 g of modified graphene oxide were added and dispersed evenly, and finally 20 g of curing agent was added and mixed evenly to obtain the waterborne polyurethane floor paint.

[0056] Example 4

[0057] A preparation process of a waterborne polyurethane floor paint comprises the following steps:

[0058] (1) dispersing 10 g of graphene oxide into 100 mL of a sulfuric acid / nitric acid mixture (sulfuric acid concentration of 80 wt %, nitric acid concentration of 60 wt %, volume ratio of sulfuric acid to nitric acid of 4:1), stirring and reacting at 100° C. for 6 h, centrifuging and washing the product to obtain carboxylated graphene oxide;

[0059] (2) 10 g of carboxylated graphene oxide was dispersed in 100 mL of DMF, and then 0.6 g of catalyst (MES buffer prepared by mixing 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and N-hydroxysuccinimide, the molar ratio of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride to N-hydroxysuccinimide was 2:1) was added, and the carboxyl groups were activated at room temperature for 60 min, and then 1.8 g of 4,4'-dithiodiphenylamine was added, and the reaction was carried out in an oil bath at 110°C for 8 h. The product was centrifuged and washed to obtain graphene oxide containing disulfide bonds;

[0060] (3) Dispersing 10 g of disulfide bond-containing graphene oxide in 100 mL of isopropanol, uniformly dispersing by ultrasonication, then adding 8 g of oleic acid chloride, stirring and reacting at 35 ° C. under a nitrogen atmosphere for 3 h, filtering, washing, and drying the product to obtain modified graphene oxide;

[0061] (4) 70 g of polyurethane resin, 18 g of hydroxyethyl methacrylate, 10 g of hydroxyethyl cellulose and 18 g of deionized water were stirred and mixed evenly, and then 2 g of dispersant, 1.5 g of leveling agent, 0.8 g of defoaming agent, 5 g of pigment and 5 g of modified graphene oxide were added and dispersed evenly, and finally 20 g of curing agent was added and mixed evenly to obtain the waterborne polyurethane floor paint.

[0062] Comparative Example 1

[0063] A preparation process of a waterborne polyurethane floor paint comprises the following steps:

[0064] (1) dispersing 10 g of graphene oxide into 100 mL of a sulfuric acid / nitric acid mixture (sulfuric acid concentration of 80 wt %, nitric acid concentration of 60 wt %, volume ratio of sulfuric acid to nitric acid of 4:1), stirring and reacting at 100° C. for 6 h, centrifuging and washing the product to obtain carboxylated graphene oxide;

[0065] (2) 10 g of carboxylated graphene oxide was dispersed in 100 mL of DMF, and then 0.6 g of catalyst (MES buffer prepared by mixing 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and N-hydroxysuccinimide, the molar ratio of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride to N-hydroxysuccinimide was 2:1) was added, and the carboxyl groups were activated at room temperature for 60 min, and then 1.8 g of 4,4'-dithiodiphenylamine was added, and the reaction was carried out in an oil bath at 110°C for 8 h. The product was centrifuged and washed to obtain graphene oxide containing disulfide bonds;

[0066] (3) 70 g of polyurethane resin, 18 g of hydroxyethyl methacrylate, 10 g of hydroxyethyl cellulose and 18 g of deionized water were stirred and mixed evenly, and then 2 g of dispersant, 1.5 g of leveling agent, 0.8 g of defoaming agent, 5 g of pigment, and 15 g of disulfide bond-containing graphene oxide were added and dispersed evenly, and finally 20 g of curing agent was added and mixed evenly to obtain the waterborne polyurethane floor paint.

[0067] Comparative Example 2

[0068] A preparation process of a waterborne polyurethane floor paint comprises the following steps:

[0069] (1) dispersing 10 g of graphene oxide into 100 mL of a sulfuric acid / nitric acid mixture (sulfuric acid concentration of 80 wt %, nitric acid concentration of 60 wt %, volume ratio of sulfuric acid to nitric acid of 4:1), stirring and reacting at 100° C. for 6 h, centrifuging and washing the product to obtain carboxylated graphene oxide;

[0070] (2) 70 g of polyurethane resin, 18 g of hydroxyethyl methacrylate, 10 g of hydroxyethyl cellulose and 18 g of deionized water were stirred and mixed uniformly, and then 2 g of dispersant, 1.5 g of leveling agent, 0.8 g of defoaming agent, 5 g of pigment and 15 g of carboxylated graphene oxide were added and dispersed uniformly, and finally 20 g of curing agent was added and mixed uniformly to obtain the waterborne polyurethane floor paint.

[0071] The floor paints prepared in Examples 1 to 4 and Comparative Examples 1 to 2 were prepared into paint films, and the performance was tested after curing for 7 days at 25°C and 60% humidity. The 750g / 500R wear resistance data was tested with reference to GB / T 1768-2006 "Determination of abrasion resistance of paints and varnishes - rotating rubber grinding wheel method", and the adhesion was tested with reference to GB / T 1720-2020 "Paint film scratching test". The remaining properties were tested with reference to GB / T 22374-2018 "Floor coating materials". The specific data are shown in Table 1.

[0072] Table 1 Floor paint performance test results

[0073]

[0074]

[0075] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A waterborne polyurethane floor paint, characterized in that: The invention is prepared from the following components by weight: 60-75 parts of polyurethane resin, 15-20 parts of hydroxyethyl methacrylate, 3-15 parts of modified graphene oxide, 6-13 parts of hydroxyethyl cellulose, 15-25 parts of curing agent, 1-3 parts of dispersant, 0.5-2 parts of leveling agent, 0.5-1 parts of defoaming agent, 3-8 parts of pigment and 10-25 parts of deionized water; The preparation method of the modified graphene oxide comprises the following steps: (1) dispersing graphene oxide in a sulfuric acid / nitric acid mixture, stirring for reaction, centrifuging and washing the product to obtain carboxylated graphene oxide; (2) dispersing the carboxylated graphene oxide in DMF, adding a catalyst and stirring at room temperature to activate the carboxyl group, adding 4,4'-dithiodiphenylamine, reacting in an oil bath, centrifuging and washing the product to obtain disulfide bond-containing graphene oxide; (3) dispersing the disulfide bond-containing graphene oxide in isopropanol, uniformly dispersing by ultrasonication, then adding oleic acid chloride, stirring for reaction, filtering, washing, and drying the product to obtain modified graphene oxide.

2. The waterborne polyurethane floor paint according to claim 1, characterized in that: In step (1), the sulfuric acid concentration in the sulfuric acid / nitric acid mixture is 60-80wt%, the nitric acid concentration is 40-60wt%, and the volume ratio of sulfuric acid to nitric acid is 2-4:

1.

3. The waterborne polyurethane floor paint according to claim 1, characterized in that: In step (1), the amount ratio of graphene oxide to sulfuric acid / nitric acid mixture is 10 g:100 mL, and the reaction conditions are stirring reaction at 80-100° C. for 6-10 hours.

4. The waterborne polyurethane floor paint according to claim 1, characterized in that: In step (2), the mass ratio of carboxylated graphene oxide, catalyst and 4,4'-dithiodiphenylamine is 100:3-6:5-18.

5. The waterborne polyurethane floor paint according to claim 1, characterized in that: In step (2), the catalyst is a MES buffer prepared by mixing 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and N-hydroxysuccinimide, and the molar ratio of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride to N-hydroxysuccinimide is 1:1 to 2:

1.

6. The waterborne polyurethane floor paint according to claim 1, characterized in that: In step (2), the activation time of the carboxyl group is 30 to 60 minutes, and the reaction conditions are oil bath reaction at 90 to 110° C. for 8 to 12 hours.

7. The waterborne polyurethane floor paint according to claim 1, characterized in that: In step (3), the usage ratio of disulfide bond-containing graphene oxide, oleic acid chloride and isopropanol is 10 g: 2-8 g: 100 mL.

8. The waterborne polyurethane floor paint according to claim 1, characterized in that: In step (3), the reaction conditions are 15-35° C. and stirring under nitrogen atmosphere for 3-7 hours.

9. A process for preparing the waterborne polyurethane floor paint according to any one of claims 1 to 8, characterized in that: The method comprises the following steps: mixing polyurethane resin, hydroxyethyl methacrylate, hydroxyethyl cellulose and deionized water in parts by weight, adding dispersant, leveling agent, defoamer, pigment and modified graphene oxide, dispersing them evenly, and finally adding curing agent, mixing them evenly to obtain the waterborne polyurethane floor paint.

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