A corrosion-resistant modified waterborne polyurethane and its preparation method and application

Abstract

The present invention belongs to the field of waterborne polyurethane materials, and specifically discloses a corrosion-resistant modified waterborne polyurethane and its preparation method and application. The raw materials for preparing the corrosion-resistant modified waterborne polyurethane of the present invention include the following components in parts by weight: 30-70 parts of carbon dioxide copolymer polyol, 30-70 parts of castor oil polyol, 30-70 parts of aliphatic diisocyanate, 1-10 parts of cross-linking agent, 4-20 parts of hydrophilic chain extender, 1-12 parts of epoxy resin, 30-60 parts of isocyanate-containing organosilicon oil, 1-15 parts of neutralizer, 100-400 parts of water, and 1-10 parts of chain extender. The present invention combines the modified isocyanate-containing organosilicon oil and anhydrous polyol mixture prepared by block copolymerization, so that the modified waterborne polyurethane exhibits more excellent corrosion resistance and adhesion.

Description

Technical Field

[0001] The invention belongs to the field of waterborne polyurethane materials, and in particular relates to corrosion-resistant modified waterborne polyurethane and a preparation method and application thereof. Background Art

[0002] Ideal sports floor materials should have good weather resistance, such as aging resistance, corrosion resistance, and wear resistance. However, in practice, polyurethane often does not have the characteristics of multiple excellent weather resistance properties. In specific application scenarios, a certain weather resistance is preferred. For outdoor floor materials made of water-based materials, there are strict requirements for their corrosion resistance. Common water-based acrylic emulsions have the defects of being hot-sticky and cold-brittle, making it difficult to take into account both hardness and toughness, and have poor adhesion. Common sports floor materials are made from polyurethane materials. Although conventional water-based polyurethanes are not easily affected by changes in hot and cold temperatures, their weather resistance, especially corrosion resistance, is relatively poor. In particular, exposure to the sun and aging will cause the chemical bonds of the water-based polyurethane to break, exacerbating the decline in the corrosion resistance, hardness and other properties of the water-based polyurethane materials. Therefore, there is still a need to develop a more corrosion-resistant water-based polyurethane coating. Summary of the Invention

[0003] In response to the above-mentioned problems in the prior art involving the corrosion resistance of water-based polyurethane topcoat for sports floors, the present invention provides a corrosion-resistant modified water-based polyurethane and its preparation method and application.

[0004] To achieve the above objectives, the following technical solutions are specifically included:

[0005] A corrosion-resistant modified waterborne polyurethane is prepared from raw materials comprising the following components in parts by weight: 30-70 parts of carbon dioxide copolymer polyol, 30-70 parts of castor oil polyol, 30-70 parts of aliphatic diisocyanate, 1-10 parts of a crosslinking agent, 4-20 parts of a hydrophilic chain extender, 1-12 parts of an epoxy resin, 30-60 parts of an isocyanate-containing organic silicone oil, 1-15 parts of a neutralizer, 100-400 parts of water, and 1-10 parts of a chain extender. The raw materials for preparing the isocyanate-containing organic silicone oil comprise the following components: 8-25 parts of an isocyanate-containing acrylate monomer and 40-80 parts of polydimethylmethylhydrogensiloxane.

[0006] As a preferred embodiment of the present invention, the weight portion of the isocyanate-containing silicone oil is 35-55 parts; the weight portion of the epoxy resin is 3-10 parts; the weight portion of the isocyanate-containing acrylate monomer is 10-20 parts; and the weight portion of the polydimethylmethylhydrogensiloxane is 50-70 parts.

[0007] As a further preferred embodiment of the present invention, 70 parts of carbon dioxide copolymer polyol, 30 parts of castor oil polyol, 45 parts of aliphatic diisocyanate, 5 parts of crosslinking agent, 15 parts of hydrophilic chain extender, 10 parts of epoxy resin, 55 parts of isocyanate-containing silicone oil, 11 parts of neutralizer, 300 parts of water, and 4 parts of chain extender; the raw materials for preparing the isocyanate-containing silicone oil include the following components: 10 parts of isocyanate-containing acrylate monomer and 50 parts of polydimethylmethylhydrogensiloxane.

[0008] As a preferred embodiment of the present invention, the isocyanate group-containing acrylate monomer includes at least one of isocyanoethyl methacrylate (MOI), ethylene glycol isocyanoethyl methacrylate (MOI-EG), isocyanoethyl acrylate (AOI), and 1,1-dimethyl diacrylate-isocyanate (BEI).

[0009] As a preferred embodiment of the present invention, the carbon dioxide copolymer polyol is copolymerized by small molecule polyether, propylene oxide and carbon dioxide, and the molecular weight of the carbon dioxide copolymer polyol is 1000 g / mol-3000 g / mol and the functionality is 2-3.

[0010] As a preferred embodiment of the present invention, the number average molecular weight of the castor oil polyol is 140 g / mol-3450 g / mol.

[0011] As a preferred embodiment of the present invention, the aliphatic diisocyanate is at least one of isophorone diisocyanate, hexamethylene diisocyanate, and hydrogenated diphenylmethane diisocyanate (hydrogenated MDI).

[0012] As a preferred embodiment of the present invention, the cross-linking agent is at least one of trimethylolpropane, glucose, and glycerol.

[0013] As a preferred embodiment of the present invention, the hydrophilic chain extender is at least one of dimethylol propionic acid, dimethylol butyric acid, and sodium sulfamate aqueous solution.

[0014] As a preferred embodiment of the present invention, the sodium sulfamate aqueous solution is a sodium sulfamate aqueous solution with a mass percentage of 50%.

[0015] As a preferred embodiment of the present invention, the neutralizing agent is triethylamine.

[0016] As a preferred embodiment of the present invention, the epoxy resin is at least one of epoxy resin E44 and epoxy resin E51.

[0017] As a preferred embodiment of the present invention, the chain extender is at least one of ethylenediamine, diethylenetriamine, and isophoronediamine.

[0018] A method for preparing corrosion-resistant modified waterborne polyurethane comprises the following steps:

[0019] (1) mixing an isocyanate group-containing acrylate monomer and polydimethylmethylhydrogensiloxane, heating and reacting them in the presence of a catalyst, and separating the reaction product to obtain an isocyanate group-containing silicone oil;

[0020] (2) mixing the carbon dioxide copolymer polyol and the castor oil polyol, and heating them to perform a dehydration reaction to obtain an anhydrous polyol mixture;

[0021] (3) adding an aliphatic diisocyanate to the anhydrous polyol mixture to react;

[0022] (4) adding a cross-linking agent, a hydrophilic chain extender and an epoxy resin to react;

[0023] (5) adding the isocyanate group-containing silicone oil, solvent, neutralizing agent and water in sequence for dispersion;

[0024] (6) adding a chain extender to react, removing the solvent, and obtaining the corrosion-resistant modified waterborne polyurethane.

[0025] As a preferred embodiment of the present invention, in step (1), the hydrogen content of the polydimethylmethylhydrogensiloxane is 0.78%-0.82%.

[0026] As a preferred embodiment of the present invention, in step (1), the catalyst is chloroplatinic acid.

[0027] As a preferred embodiment of the present invention, in step (1), the mass fraction of the catalyst is 0.01-1 parts.

[0028] As a preferred embodiment of the present invention, in step (1), the reaction temperature is 70-100° C., and the reaction time is 6-10 h.

[0029] As a further preferred embodiment of the present invention, in step (1), the reaction temperature is 90° C. and the reaction time is 8 h.

[0030] As a preferred embodiment of the present invention, in step (1), the method for separating the reaction product is vacuum distillation, and the specific steps of vacuum distillation are: heating the reaction system to 100-160°C and vacuum distilling under negative pressure for 20-120 minutes.

[0031] As a further preferred embodiment of the present invention, in step (1), the method for separating the reaction product is vacuum distillation, and the specific steps of vacuum distillation are: heating the reaction system to 120°C and performing vacuum distillation for 30 minutes under a negative pressure of 0.095 MPa.

[0032] As a preferred embodiment of the present invention, in step (2), the specific steps of the dehydration reaction include: performing the dehydration reaction under negative pressure and a temperature of 70-120° C. for 0.5-3 h.

[0033] As a further preferred embodiment of the present invention, in step (2), the specific steps of the dehydration reaction include: performing the dehydration reaction under the conditions of a negative pressure of 0.095 MPa and a temperature of 100° C. for 2 hours.

[0034] As a preferred embodiment of the present invention, in step (3), the reaction temperature is 75-90° C., and the reaction time is 1-4 h.

[0035] As a further preferred embodiment of the present invention, in step (3), the reaction temperature is 85° C. and the reaction time is 3 h.

[0036] As a preferred embodiment of the present invention, in step (3), the reaction is carried out under the condition of catalysis by a catalyst, and the catalyst is organic bismuth.

[0037] As a preferred embodiment of the present invention, in step (4), the reaction temperature is 60-75° C., and the reaction time is 1-3 h.

[0038] As a further preferred embodiment of the present invention, in step (4), the reaction temperature is 70° C., and the reaction time is 2 h.

[0039] As a preferred embodiment of the present invention, in step (5), the dispersion temperature is 50-80° C., and the reaction time is 5 min-60 min.

[0040] As a preferred embodiment of the present invention, in step (5), the dispersion speed is 1000-2000 rpm.

[0041] As a further preferred embodiment of the present invention, in step (5), the dispersion speed is 1500 rpm.

[0042] As a preferred embodiment of the present invention, in step (5), the solvent is acetone or butanone.

[0043] As a preferred embodiment of the present invention, in step (6), the reaction temperature is 50-80° C., and the reaction time is 10 min-5 h.

[0044] As a further preferred embodiment of the present invention, in step (6), the reaction temperature is 50° C., and the reaction time is 20 min.

[0045] As a preferred embodiment of the present invention, in step (6), the reaction speed is 1000-2000 rpm.

[0046] As a further preferred embodiment of the present invention, in step (6), the dispersion speed is 1500 rpm.

[0047] The present invention also provides an application of the corrosion-resistant modified waterborne polyurethane in preparing waterborne polyurethane coatings.

[0048] A waterborne polyurethane coating is prepared from raw materials comprising the following components in parts by weight: 80-120 parts of corrosion-resistant modified waterborne polyurethane, 10-50 parts of filler, and 0.1-5 parts of waterborne additive.

[0049] As a further preferred embodiment of the present invention, the filler is at least one of talc powder with a mesh size of 400 to 1250 mesh, heavy calcium carbonate, kaolin, and titanium dioxide.

[0050] As a preferred embodiment of the present invention, the aqueous auxiliary agent is at least one of a defoaming agent, a wetting agent, a preservative, a thickener, and a pH regulator.

[0051] The raw materials for preparing the waterborne polyurethane coating include the following components in parts by weight: 100 parts of the corrosion-resistant modified waterborne polyurethane, 15 parts of filler, 0.3 parts of dispersant, 0.4 parts of wetting agent, 0.2 parts of defoaming agent, 0.1 parts of preservative, and 1 part of thickener.

[0052] Compared with the prior art, the present invention has the following beneficial effects: the present invention uses an isocyanate-containing acrylate monomer and polydimethylmethylhydrogensiloxane to prepare an isocyanate-containing silicone oil, which is then grafted and cross-linked with a prepared epoxy-containing terminal isocyanate polyurethane prepolymer through an amine chain extender to form a silicone-modified water-based polyurethane with a specific cross-linking structure, which exhibits better corrosion resistance and adhesion. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 This is a schematic diagram of the synthesis of isocyanate-containing silicone oil in Example 1. DETAILED DESCRIPTION

[0054] In order to better illustrate the purpose, technical solutions and advantages of the present invention, the present invention will be further described below through specific embodiments.

[0055] Raw material information of Examples and Comparative Examples:

[0056] Castor oil polyol: Vantellus GR110; dispersant: Dow dispersant 1124; wetting agent: Dow wetting agent BD109; defoaming agent: Nopco NXZ defoaming agent; preservative: Dow preservative 631; thickener: Rohm and Haas thickener 8w mix.

[0057] The carbon dioxide copolymer polyol and the polyether polyol are both made of difunctional polyol copolymers, namely, carbon dioxide copolymer diol, polybutadiene diol and polyether diol, which are commercially available. The molar fraction of the polycarbonate group in the carbon dioxide copolymer diol is 0.3.

[0058] Unless otherwise specified, the same components used in the examples and comparative examples are of the same type.

[0059] Example 1

[0060] The corrosion-resistant modified waterborne polyurethane of this embodiment includes the following raw material components in parts by weight: 30 parts of carbon dioxide copolymer polyol, 70 parts of castor oil polyol, 45 parts of aliphatic diisocyanate, 5 parts of crosslinking agent, 15 parts of hydrophilic chain extender, 10 parts of epoxy resin, 55 parts of isocyanate-containing silicone oil, 11 parts of neutralizer, 300 parts of water, and 4 parts of chain extender; the raw materials for preparing the isocyanate-containing silicone oil include the following components: 10 parts of isocyanate-containing acrylate monomer and 50 parts of polydimethylmethylhydrogensiloxane.

[0061] A method for preparing corrosion-resistant modified waterborne polyurethane comprises the following steps:

[0062] (1) Preparation of an isocyanate-containing silicone oil: 10 parts by mass of isocyanoethyl methacrylate and 50 parts of polydimethylmethylhydrogensiloxane (hydrogen content 0.78%-0.82%) were added to a reactor under stirring at 1000-2000 rpm, and then 0.25 parts of chloroplatinic acid were added. The mixture was heated to 90° C. and reacted for 8 h. After the reaction was completed, the mixture was heated to 120° C. and the reaction product was separated by vacuum distillation at a negative pressure of 0.095 MPa for 30 min to obtain the isocyanate-containing silicone oil.

[0063] (2) Add 30 parts by mass of carbon dioxide copolymer polyol (Mn = 3000 g / mol) and 70 parts of castor oil polyol (Fantrous GR110) to a reactor, heat to 100° C., and dehydrate under a negative pressure of 0.095 MPa for 2 h to obtain an anhydrous polyol mixture;

[0064] (3) adding 45 parts of isophorone diisocyanate and 0.08 parts of organic bismuth to the anhydrous polyol mixture, and reacting at 85° C. for 3 hours;

[0065] (4) The system temperature was lowered to 70°C, and 5 parts of glycerol, 15 parts of dimethylolpropionic acid, and 10 parts of epoxy resin E44 were added and reacted for 2 hours;

[0066] (5) Control the system temperature at 70°C, add 55 parts of the isocyanate-containing silicone oil prepared in step (1), cool the system temperature to 50°C, add 50 parts of acetone and 11 parts of triethylamine, add 300 parts of deionized water under high-speed stirring, and disperse at 1000-2000 rpm for 15 minutes;

[0067] (6) Add 4 parts of ethylenediamine while controlling the temperature at 50° C., stir the mixture at 1000-2000 rpm for 20 minutes, and then remove the solvent to obtain the corrosion-resistant modified waterborne polyurethane.

[0068] A method for preparing a waterborne polyurethane coating comprises the following steps: mixing, by mass, 100 parts of the corrosion-resistant modified waterborne polyurethane prepared in step (6) above, 15 parts of 1250-mesh kaolin, 0.3 parts of a dispersant, 0.4 parts of a wetting agent, 0.2 parts of a defoaming agent, 0.1 parts of a preservative and 1 parts of a thickener, and stirring the mixture to obtain a waterborne polyurethane coating.

[0069] Example 2

[0070] Compared with Example 1, the difference is that, in the preparation of the isocyanate group-containing silicone oil in this example, 20 parts of isocyanoethyl methacrylate and 50 parts of polydimethylmethylhydrogensiloxane (hydrogen content 0.78%-0.82%) are used.

[0071] Example 3

[0072] Compared with Example 1, the difference is that the amount of isocyanate group-containing silicone oil added in this example is 35 parts.

[0073] Example 4

[0074] Compared with Example 1, the difference is that the amount of epoxy resin E44 added in this example is 3 parts.

[0075] Example 5

[0076] Compared with Example 1, the difference is that the amount of carbon dioxide copolymer polyol added in this example is 70 parts, and the amount of castor oil polyol added in this example is 30 parts.

[0077] Comparative Example 1

[0078] Compared with Example 1, the difference is that in step (2), 30 parts of carbon dioxide copolymer polyol and 70 parts of castor oil polyol are replaced by 100 parts of polyether polyol (Mn=2000 g / mol).

[0079] Comparative Example 2

[0080] Compared with Example 1, the difference is that in step (2), 30 parts of carbon dioxide copolymer polyol and 70 parts of castor oil polyol are replaced by 100 parts of polyester polyol PBA2000.

[0081] Comparative Example 3

[0082] Compared with Example 1, the difference is that epoxy resin E44 is not added in step (4).

[0083] Comparative Example 4

[0084] Compared with Example 1, the difference is that step (1) is not performed, and the isocyanate-containing silicone oil is replaced by an equal amount of silane coupling agent KH550.

[0085] Comparative Example 5

[0086] Compared with Example 1, the difference is that castor oil polyol is not added.

[0087] Application and testing of waterborne polyurethane coatings

[0088] The waterborne polyurethane coatings prepared in the Examples and Comparative Examples were coated onto glass plates with 5% waterborne polyurethane curing agent and dried at room temperature for 7 days before testing. Each sample was immersed in a 20% aqueous sodium hydroxide solution for 168 hours, a 10% aqueous sulfuric acid solution for 168 hours, and a 3% aqueous sodium hydroxide solution for 500 hours. The appearance of the product was then observed. The testing method followed GB / T 22374-2018. The results are shown in Table 1.

[0089] The above-mentioned water-based polyurethane curing agent is mainly prepared from the following components in parts by mass: 95-110 parts of isocyanate trimer, 1-10 parts of hydrophilic monomer, and 0-2 parts of a first neutralizer; wherein the hydrophilic monomer is at least one of polyethylene glycol monomethyl ether, cyclohexylaminopropanesulfonic acid, and cyclohexylaminoethanesulfonic acid; the first neutralizer is triethylamine; and the isocyanate trimer is hexamethylene diisocyanate trimer.

[0090] The waterborne polyurethane curing agent prepared from the above components can be used in conjunction with the waterborne polyurethane of the present invention. The resulting waterborne polyurethane product can be cured and formed at room temperature without the need for high-temperature baking, which is beneficial for expanding the application range of waterborne polyurethane products. The waterborne polyurethane curing agent controls the hydrophilic groups in the curing agent within an appropriate range through the ratio of the isocyanate trimer, the hydrophilic monomer, and the first neutralizer, thereby avoiding the reduction of the water resistance and corrosion resistance of the waterborne polyurethane product due to the introduction of a large number of hydrophilic groups. The curing agent effectively balances the number of hydrophilic groups, water resistance, and crosslinking properties.

[0091] Specifically, the preparation method of the above-mentioned water-based polyurethane curing agent is as follows: the preparation method of the polyurethane curing agent is: in a vacuum environment at 100°C, stirring cyclohexylaminopropanesulfonic acid for 3 hours for standby use; under normal temperature conditions, adding 100 parts by mass of hexamethylene diisocyanate trimer and 3 parts by mass of cyclohexylaminopropanesulfonic acid into a reactor, then heating to 40°C, stirring for 4 hours, and then cooling to 25°C, adding 1.4 parts of triethylamine, and stirring for another 0.5 hour to obtain a water-based polyurethane curing agent. The content of isocyanate groups in the curing agent is measured to be 23% by the di-n-butylamine calibration method.

[0092] Table 1 Corrosion resistance test results of coatings of Examples and Comparative Examples

[0093]

[0094]

[0095] Compared with Example 1, in the isocyanate-based silicone process in Example 2, the amount of isocyanate ethyl methacrylate is relatively large, and the amount of hydrogen-containing silicone oil is relatively small, and the reaction completeness is slightly lower. Therefore, the bonding strength of the paint coating is slightly reduced, but it does not affect its overall corrosion resistance.

[0096] Compared with Example 1, the amount of isocyanate-containing silicone in Example 3 is reduced, so there is less silicone wrapped around the resin, which reduces the protection of the resin body and has a greater impact on the strength of the paint coating after immersion in water, but does not affect its overall corrosion resistance.

[0097] Compared with Example 1, the amount of epoxy resin used in Example 4 is reduced and the degree of cross-linking is lower, so the bonding strength of the paint coating is slightly reduced, but it does not affect the overall corrosion resistance.

[0098] Compared with Example 1, the amount of carbon dioxide copolymer polyol used in Example 5 is increased, the carbonate bond content is high, the polarity is strong, and the cohesive energy is large, which can not only improve the strength of the paint coating, but also improve its bonding strength.

[0099] Compared with Example 1, the polyol in Comparative Example 1 adopts polyether, which has lower cohesive energy and poorer adhesion. Its ether bond has poor chemical corrosion resistance, and the bonding strength also decreases after being immersed in water.

[0100] Compared with Example 1, Comparative Example 2 uses polyester polyol, which has strong cohesive energy but is not resistant to hydrolysis and has poor water resistance. Therefore, the paint coating prepared therefrom has high bonding strength, but the bonding strength is greatly reduced after immersion in water, and the paint coating has poor chemical corrosion resistance.

[0101] Compared with Example 1, no epoxy resin was added in Comparative Example 3, resulting in a decrease in the crosslinking degree of the system and thus a decrease in various properties.

[0102] Compared with Example 1, the silane coupling agent used in Comparative Example 4 has a smaller molecular weight and cannot effectively wrap around the entire polyurethane resin, so various properties are poor.

[0103] Compared with Example 1, in Comparative Example 5, only carbon dioxide copolymer polyol is used without castor oil, so it has more carbonate bonds, larger cohesive energy, and better adhesion strength of the coating. However, its hydrophobicity is not as good as castor oil, so the adhesion strength of the coating after immersion in water is slightly reduced, and it contains some ether bonds, so the corrosion resistance of the coating is reduced to a certain extent.

[0104] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A method for preparing corrosion-resistant modified waterborne polyurethane, characterized in that: The raw materials for preparing the corrosion-resistant modified waterborne polyurethane include the following components in parts by weight: 30-70 parts of carbon dioxide copolymer polyol, 30-70 parts of castor oil polyol, 30-70 parts of aliphatic diisocyanate, 1-10 parts of a crosslinking agent, 4-20 parts of a hydrophilic chain extender, 1-12 parts of an epoxy resin, 30-60 parts of an isocyanate-containing silicone oil, 1-15 parts of a neutralizer, 100-400 parts of water, and 1-10 parts of a chain extender; the raw materials for preparing the isocyanate-containing silicone oil include the following components: 8-25 parts of an isocyanate-containing acrylate monomer and 40-80 parts of polydimethylmethylhydrogensiloxane; the hydrophilic chain extender is at least one of dimethylolpropionic acid, dimethylolbutyric acid, and an aqueous sodium sulfamate solution; and the chain extender is at least one of ethylenediamine, diethylenetriamine, and isophoronediamine; The steps include: (1) mixing an isocyanate group-containing acrylate monomer and polydimethylmethylhydrogensiloxane, heating them to react under a catalyst, and separating the reaction product to obtain an isocyanate group-containing silicone oil; (2) mixing the carbon dioxide copolymer polyol and the castor oil polyol, heating and performing a dehydration reaction to obtain an anhydrous polyol mixture; (3) adding an aliphatic diisocyanate to the anhydrous polyol mixture to carry out a reaction; (4) adding a cross-linking agent, a hydrophilic chain extender and an epoxy resin to react; (5) adding the isocyanate group-containing silicone oil, solvent, neutralizing agent and water in sequence for dispersion; (6) adding a chain extender to react, removing the solvent, and obtaining the corrosion-resistant modified waterborne polyurethane.

2. The method for preparing the corrosion-resistant modified waterborne polyurethane according to claim 1, wherein: The weight portion of the isocyanate-containing silicone oil is 35-55 parts; the weight portion of the epoxy resin is 3-10 parts; the weight portion of the isocyanate-containing acrylate monomer is 10-20 parts; and the weight portion of the polydimethylmethylhydrogensiloxane is 50-70 parts.

3. The method for preparing the corrosion-resistant modified waterborne polyurethane according to claim 1, wherein: Include at least one of the following (a)-(d): (a) The carbon dioxide copolymer polyol is copolymerized by small molecule polyether, propylene oxide and carbon dioxide, and the molecular weight of the carbon dioxide copolymer polyol is 1000g / mol-3000g / mol; (b) the number average molecular weight of the castor oil polyol is 140 g / mol-3450 g / mol; (c) The aliphatic diisocyanate is at least one of isophorone diisocyanate, hexamethylene diisocyanate, and hydrogenated diphenylmethane diisocyanate; (d) The cross-linking agent is at least one of trimethylolpropane, glucose, and glycerol.

4. The method for preparing the corrosion-resistant modified waterborne polyurethane according to claim 1, wherein: The epoxy resin is at least one of epoxy resin E44 and epoxy resin E51; the isocyanate group-containing acrylate monomer includes at least one of isocyanoethyl methacrylate and isocyanoethyl acrylate.

5. The method for preparing the corrosion-resistant modified waterborne polyurethane according to claim 1, wherein: In step (1), the hydrogen content of the polydimethylmethylhydrogensiloxane is 0.78%-0.82%; in step (1), the catalyst is chloroplatinic acid.

6. The method for preparing the corrosion-resistant modified waterborne polyurethane according to claim 1, wherein: Include at least one of the following AHs: A. In step (1), the reaction temperature is 70-100°C and the reaction time is 6-10h; B. In step (1), the method for separating the reaction product is vacuum distillation, and the specific steps of vacuum distillation are: heating the reaction system to 100-160°C and vacuum distilling under negative pressure for 20-120 minutes; C. In step (2), the specific steps of the dehydration reaction include: carrying out the dehydration reaction under negative pressure and a temperature of 70-120° C. for 0.5-3 h; D. In step (3), the reaction temperature is 75-90°C and the reaction time is 1-4h; E. In step (4), the reaction temperature is 60-75°C and the reaction time is 1-3h; F. In step (5), the dispersion temperature is 50-80°C, the reaction time is 5 min-60 min, and the dispersion speed is 1000-2000 rpm; G. In step (6), the reaction temperature is 50-80°C and the reaction time is 10 min-5 h; H. In step (5), the solvent is acetone or butanone.

7. A waterborne polyurethane coating, characterized in that: The raw materials for its preparation include the following components in parts by weight: 80-120 parts of the corrosion-resistant modified waterborne polyurethane prepared by the preparation method of the corrosion-resistant modified waterborne polyurethane according to any one of claims 1-6, 10-50 parts of filler, and 0.1-5 parts of a water-based auxiliary agent.

8. The waterborne polyurethane coating according to claim 7, wherein The filler is at least one of 400-1250 mesh talc, heavy calcium carbonate, kaolin, and titanium dioxide; and the aqueous additive is at least one of a defoamer, a wetting agent, a preservative, a thickener, and a pH regulator.

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