Moistureproof water-based nano efficient sealant and preparation method thereof

Abstract

The invention discloses a moisture-proof water-based nano efficient sealant and a preparation method thereof, and relates to the technical field of sealants. According to the invention, nitrogen-nitrogen triple bonds are introduced to nano-silica by using 2-hydroxy-3-fluorobenzonitrile, and pi electron cloud in the nitrogen-nitrogen triple bonds can absorb ultraviolet energy, so that an anti-ultraviolet effect is achieved; secondly, a KH-570 silane coupling agent, diphenyl silanediol and p-methylphenyl silane are utilized to form silicon acyl heterocyclic molecules rich in Si = O part, and the nano silicon dioxide particles can effectively improve the hydrophobic property of the cured polyurethane sealant, so that the polyurethane sealant has a very good moisture-proof effect; the silicon acyl heterocyclic molecules can generate non-covalent interaction with amino groups in a polyurethane molecular chain, and when a polyurethane side chain is subjected to cross-linking curing, the sealing speed, the sealing effect and the anti-aging capability of the polyurethane sealant can be effectively improved. The moisture-proof water-based nano efficient sealant prepared by the invention has moisture-proof, ultraviolet-proof and anti-aging effects.

Description

Technical Field

[0001] The invention relates to the technical field of sealants, in particular to a moisture-proof water-based nano high-efficiency sealant and a preparation method thereof. Background Art

[0002] The higher the humidity, the higher the moisture content in the sealant, which will cause the viscosity of the sealant to decrease, thus affecting its fluidity and coating effect. Low-viscosity sealants may not form a uniform sealing layer, thus affecting their moisture-proof performance. For some types of sealants, such as epoxy resin mortar floor coatings, excessive humidity may cause the coating quality to deteriorate. Excessive humidity may cause condensation on the coating surface. For solvent-based amine-cured epoxy coatings, condensed water will destroy the curing agent, causing problems such as whitening, gloss loss, stickiness and back-tackiness of the coating film. In addition, excessive humidity may also make the hardening process abnormally slow, or even unable to harden completely, thus affecting the sealing of the sealant.

[0003] In a humid environment, metals and other corrosive materials are more susceptible to electrochemical corrosion. If sealants fail to effectively isolate water and moisture, these materials will accelerate corrosion, resulting in performance degradation and structural damage. Long-term exposure to a humid environment will also cause the sealant itself to age. Water and moisture will promote the decomposition and reaction of certain chemicals in the sealant, resulting in a decrease in sealant performance, such as reduced hardness and reduced elasticity. For example, the application of concrete sealers in humid weather may cause the ground to turn white and lose gloss, affecting the appearance and service life. In addition, moisture may penetrate into the structure, causing problems such as steel corrosion and reduced structural strength.

[0004] Therefore, the present invention prepares a moisture-proof water-based nano high-efficiency sealant, which has the effects of moisture-proof, UV-proof and anti-aging. Summary of the invention

[0005] The purpose of the present invention is to provide a moisture-proof water-based nano high-efficiency sealant and a preparation method thereof, so as to solve the problems existing in the prior art.

[0006] In order to solve the above technical problems, the present invention provides the following technical solutions: a moisture-proof water-based nano-efficient sealant, which is prepared by adding modified nano-silicon dioxide, diphenylsilanediol and p-tolylsilane into modified waterborne polyurethane.

[0007] Furthermore, the modified nano-silica is prepared by activating the hydroxyl activity on the surface of the nano-silica using ultraviolet rays and ozone, and then adding 2-hydroxy-3-fluorobenzonitrile.

[0008] Furthermore, the modified waterborne polyurethane is prepared by adding KH-570 silane coupling agent into waterborne polyurethane.

[0009] Furthermore, a method for preparing a moisture-proof water-based nano-efficient sealant comprises the following preparation steps:

[0010] (1) immersing silica powder with a particle size of 80 to 100 nm in an acetone solution, ultrasonically treating at 30 to 40 kHz for 30 to 40 minutes, filtering, taking out the solid, washing it with deionized water for 2 to 3 times, drying it at room temperature, 1.72 MPa and nitrogen protection for 1 to 2 hours, placing it in a piranha solution with a mass 4 to 5 times that of the silica powder for 30 to 45 minutes, filtering, taking out the solid, washing it with deionized water for 2 to 3 times, drying it at room temperature, 1.72 MPa and nitrogen protection for 1 to 2 hours, and then irradiating it with ultraviolet light at room temperature, 1.35 MPa and ozone protection to obtain hydroxylated silica powder;

[0011] (2) adding hydroxylated silica powder to 2-hydroxy-3-fluorobenzonitrile with a mass of 3 to 6 times that of the hydroxylated silica powder, heating to 50 to 60° C., stirring at 600 to 800 r / min for 8 to 10 hours, and naturally cooling to room temperature to obtain a modified nano-silica sol;

[0012] (3) Mix polytetrahydrofuran and TMP in a mass ratio of 50 to 60:1, heat to 100 to 120°C, evacuate to -0.05 to -0.1 MPa, dehydrate for 10 to 20 minutes, cool to 40 to 50°C, add isophorone diisocyanate at a mass of 0.1 to 0.2 times that of polytetrahydrofuran, add DY-20 at a mass of 0.01 to 0.05 times that of polytetrahydrofuran, heat to 70 to 80°C, react for 3 to 5 hours, cool to 50 to 55°C, add propylene glycol at a mass of 0.05 to 0.15 times that of polytetrahydrofuran, and add propylene glycol at a mass of 0.05 to 0.15 times that of polytetrahydrofuran. ketone, add butanediol in an amount of 0.1 to 0.2 times the mass of polytetrahydrofuran, add DMPA in an amount of 0.2 to 0.3 times the mass of polytetrahydrofuran, heat to 60 to 65°C for reaction for 2 to 3 hours, cool to 40°C, add triethylamine in an amount of 0.1 to 0.2 times the mass of polytetrahydrofuran, add deionized water in an amount of 3 to 5 times the mass of polytetrahydrofuran under stirring at 700 to 800 r / min, continue stirring for 10 to 15 minutes, add IPDA in an amount of 0.02 to 0.05 times the mass of polytetrahydrofuran, and disperse at high speed to obtain an aqueous polyurethane solution;

[0013] (4) The modified waterborne polyurethane solution and the modified nano-silica solution are mixed in a mass ratio of 10 to 15:1 to obtain a mixed solution, stirred at 200 to 300 r / min for 30 to 45 min, 0.1 to 0.3 times the mass of the mixed solution of the organic silicon solution is added, the mixture is heated to 40 to 50° C. and reacted for 1 to 2 h, and then naturally cooled to room temperature to obtain a moisture-proof waterborne nano-high-efficiency sealant.

[0014] Furthermore, the piranha solution in step (1) is prepared by mixing concentrated sulfuric acid and hydrogen peroxide in a volume ratio of 2 to 2.5:1.

[0015] Furthermore, in step (2), the ultraviolet light irradiation is to receive ultraviolet light with wavelengths of 185 nm and 254 nm for 3 to 6 hours.

[0016] Furthermore, in the step (3), the high-speed dispersion is performed using a 22KW high-speed disperser for 1 to 2 hours.

[0017] Furthermore, the molecular weight of the polytetrahydrofuran in step (3) is 2000-3000.

[0018] Furthermore, the modified waterborne polyurethane in step (4) is prepared by mixing the waterborne polyurethane solution and KH-570 in a mass ratio of 8 to 10:1, and stirring at 200 to 300 r / min for 30 to 60 minutes.

[0019] Furthermore, in the step (4), the organosilicon solution is prepared by mixing diphenylsilanediol and p-tolylsilane in a mass ratio of 1 to 2:1 and stirring at 200 to 300 r / min for 30 to 60 min.

[0020] Compared with the prior art, the beneficial effects achieved by the present invention are:

[0021] The invention firstly utilizes 2-hydroxy-3-fluorobenzonitrile to prepare modified nano silicon dioxide, and then adds the modified nano silicon dioxide, diphenylsilanediol and p-tolylsilane into waterborne polyurethane to obtain a moisture-proof waterborne nano high-efficiency sealant, so as to achieve moisture-proof, UV-proof and anti-aging effects.

[0022] Firstly, ultraviolet rays and ozone are used to activate the activity of hydroxyl groups on the surface of nano-silica, and 2-hydroxy-3-fluorobenzonitrile is added to obtain modified nano-silica. The hydroxyl groups on 2-hydroxy-3-fluorobenzonitrile will condense with the surface active hydroxyl groups of nano-silica to introduce the nitrogen-nitrogen triple bond into the nano-silica. The π electron cloud in the nitrogen-nitrogen triple bond can absorb ultraviolet energy, thereby achieving an anti-ultraviolet effect. The introduction of benzonitrile will also improve the stability of nano-silica, improve the agglomeration effect, and thus improve the hydrophobicity of nano-silica.

[0023] Secondly, waterborne polyurethane is modified by KH-570 silane coupling agent, and modified nano-silica, diphenylsilanediol and p-tolylsilane are added at the same time. The nano-silica particles can effectively improve the hydrophobic properties of the polyurethane sealant after curing, so that the polyurethane sealant has a good moisture-proof effect. The acidity and nucleophilicity of the KH-570 coupling agent are combined with diphenylsilanediol and p-tolylsilane in turn to form silicyl heterocyclic molecules rich in Si=O parts. The silicyl heterocyclic molecules can undergo non-covalent interactions with the amino groups in the polyurethane molecular chain. When the polyurethane side chains are cross-linked and cured, the sealing speed, sealing effect and anti-aging ability of the polyurethane sealant can be effectively improved. DETAILED DESCRIPTION

[0024] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0025] In order to more clearly illustrate the method provided by the present invention, the following examples are used to describe in detail the various index testing methods of the moisture-proof water-based nano high-efficiency sealant prepared in the following examples are as follows:

[0026] Moisture-proof performance: After the moisture-proof water-based nano-high-efficiency sealants of the same mass prepared in the embodiment and the comparative example were cured, the surface water contact angle was tested.

[0027] Anti-ultraviolet performance: After the moisture-proof water-based nano high-efficiency sealants of the same mass prepared in the embodiment and the comparative example were cured, ultraviolet irradiation conditions were simulated to observe the performance changes under long-term ultraviolet irradiation, the corresponding shear strength was tested according to GB / T 7124, and the failure mode was recorded.

[0028] Anti-aging performance: After the moisture-proof water-based nano high-efficiency sealants of the same mass prepared in the embodiment and the comparative example were cured, they were placed under high temperature and high humidity and low temperature and low humidity conditions for alternating testing to simulate their aging process in a humid environment and outdoor environment, and their performance changes were observed. The corresponding shear strength was tested according to GB / T 7124, and the failure mode was recorded.

[0029] Example 1

[0030] A method for preparing a moisture-proof water-based nano high-efficiency sealant comprises the following preparation steps:

[0031] (1) concentrated sulfuric acid and hydrogen peroxide are mixed in a volume ratio of 2:1 to prepare a piranha solution;

[0032] (2) immersing silica powder with a particle size of 80 nm in an acetone solution, ultrasonically treating at 30 kHz for 30 min, filtering, taking the solid, washing it twice with deionized water, drying it for 1 h at room temperature, 1.72 MPa and nitrogen protection, placing it in a piranha solution with a mass 4 times that of the silica powder for 30 min, filtering, taking the solid, washing it twice with deionized water, drying it for 1 h at room temperature, 1.72 MPa and nitrogen protection, and then irradiating it with ultraviolet light at wavelengths of 185 nm and 254 nm for 3 h at room temperature, 1.35 MPa and ozone protection to obtain hydroxylated silica powder;

[0033] (3) adding hydroxylated silica powder to 2-hydroxy-3-fluorobenzonitrile with a mass 3 times that of the hydroxylated silica powder, heating to 50° C., stirring at 600 r / min for 8 h, and naturally cooling to room temperature to obtain a modified nano-silica sol;

[0034] (4) Mix polytetrahydrofuran (2000 molecular weight) and TMP in a mass ratio of 50:1, heat to 100°C, evacuate to -0.05 MPa, dehydrate for 10 min, cool to 40°C, add isophorone diisocyanate (0.1 times the mass of polytetrahydrofuran), add DY-20 (0.01 times the mass of polytetrahydrofuran), heat to 70°C for 3 h, cool to 50°C, add acetone (0.05 times the mass of polytetrahydrofuran), add polytetrahydrofuran, and add 1% acetone. Add 0.1 times the mass of tetrahydrofuran butanediol, 0.2 times the mass of polytetrahydrofuran DMPA, heat to 60°C for reaction for 2h, cool to 40°C, add 0.1 times the mass of polytetrahydrofuran triethylamine, add 3 times the mass of polytetrahydrofuran deionized water under stirring at 7000r / min, continue stirring for 10min, add 0.02 times the mass of polytetrahydrofuran IPDA, and disperse for 1h with a 22KW high-speed disperser to obtain an aqueous polyurethane solution;

[0035] (5) mixing the aqueous polyurethane solution and KH-570 at a mass ratio of 8:1, and stirring at 200 r / min for 30 min to obtain a modified aqueous polyurethane;

[0036] (6) mixing diphenylsilanediol and p-tolylsilane in a mass ratio of 1:1, and stirring at 200 r / min for 30 min to prepare an organosilicon solution;

[0037] (7) The modified waterborne polyurethane solution and the modified nano-silica solution were mixed in a mass ratio of 10:1 to obtain a mixed solution, and the mixture was stirred at 200 r / min for 30 min. A silicone solution with a mass of 0.1 times that of the mixed solution was added, and the mixture was heated to 40° C. for reaction for 1 h, and then naturally cooled to room temperature to obtain a moisture-proof waterborne nano-high-efficiency sealant.

[0038] Example 2

[0039] A method for preparing a moisture-proof water-based nano high-efficiency sealant comprises the following preparation steps:

[0040] (1) concentrated sulfuric acid and hydrogen peroxide were mixed in a volume ratio of 2.2:1 to prepare a piranha solution;

[0041] (2) immersing silica powder with a particle size of 90 nm in an acetone solution, ultrasonically treating at 35 kHz for 35 min, filtering, taking the solid, washing it twice with deionized water, drying it for 1.5 h at room temperature, 1.72 MPa and nitrogen protection, placing it in a piranha solution with a mass 4.5 times that of the silica powder for 40 min, filtering, taking the solid, washing it twice with deionized water, drying it for 1.5 h at room temperature, 1.72 MPa and nitrogen protection, and then irradiating it with ultraviolet light at wavelengths of 185 nm and 254 nm for 4 h at room temperature, 1.35 MPa and ozone protection to obtain hydroxylated silica powder;

[0042] (3) adding hydroxylated silica powder to 2-hydroxy-3-fluorobenzonitrile with a mass 5 times that of the hydroxylated silica powder, heating to 55° C., stirring at 700 r / min for 9 h, and naturally cooling to room temperature to obtain a modified nano-silica sol;

[0043] (4) Mix polytetrahydrofuran (PTHF) with a molecular weight of 2500 and TMP in a mass ratio of 55:1, heat to 110°C, evacuate to -0.08 MPa, dehydrate for 15 min, cool to 45°C, add isophorone diisocyanate (0.15 times the mass of PTHF), add DY-20 (0.03 times the mass of PTHF), heat to 75°C for reaction for 5 h, cool to 52°C, add acetone (0.1 times the mass of PTHF), add PTHF, and add 1% acetone. Add 0.15 times the mass of butanediol to the polytetrahydrofuran, add 0.25 times the mass of DMPA to the polytetrahydrofuran, heat to 63°C for reaction for 2h, cool to 40°C, add 0.15 times the mass of triethylamine to the polytetrahydrofuran, add 4 times the mass of deionized water to the polytetrahydrofuran under stirring at 750r / min, continue stirring for 12min, add 0.03 times the mass of IPDA to the polytetrahydrofuran, and disperse for 1h with a 22KW high-speed disperser to obtain an aqueous polyurethane solution;

[0044] (5) mixing the aqueous polyurethane solution and KH-570 at a mass ratio of 9:1, and stirring at 250 r / min for 45 min to obtain a modified aqueous polyurethane;

[0045] (6) mixing diphenylsilanediol and p-tolylsilane in a mass ratio of 1.5:1, and stirring at 250 r / min for 45 min to prepare an organosilicon solution;

[0046] (7) The modified waterborne polyurethane solution and the modified nano-silica solution were mixed in a mass ratio of 13:1 to obtain a mixed solution, which was stirred at 250 r / min for 40 min, and a silicone solution 0.2 times the mass of the mixed solution was added. The mixture was heated to 45° C. and reacted for 1.5 h, and then naturally cooled to room temperature to obtain a moisture-proof waterborne nano-high-efficiency sealant.

[0047] Example 3

[0048] A method for preparing a moisture-proof water-based nano high-efficiency sealant comprises the following preparation steps:

[0049] (1) concentrated sulfuric acid and hydrogen peroxide were mixed in a volume ratio of 2.5:1 to prepare a piranha solution;

[0050] (2) immersing silica powder with a particle size of 100 nm in an acetone solution, ultrasonically treating at 40 kHz for 40 min, filtering, taking the solid, washing it with deionized water for 3 times, drying it at room temperature, 1.72 MPa and nitrogen protection for 2 h, placing it in a piranha solution with a mass 5 times that of the silica powder for 45 min, filtering, taking the solid, washing it with deionized water for 3 times, drying it at room temperature, 1.72 MPa and nitrogen protection for 2 h, and then irradiating it with ultraviolet light at wavelengths of 185 nm and 254 nm for 6 h at room temperature, 1.35 MPa and ozone protection to obtain hydroxylated silica powder;

[0051] (3) adding hydroxylated silica powder to 2-hydroxy-3-fluorobenzonitrile with a mass of 3 to 6 times that of the hydroxylated silica powder, heating to 60° C., stirring at 800 r / min for 10 h, and naturally cooling to room temperature to obtain a modified nano-silica sol;

[0052] (4) Mix polytetrahydrofuran (PTHF) with a molecular weight of 2000 to 3000 and TMP in a mass ratio of 60:1, heat to 120°C, evacuate to -0.1 MPa, dehydrate for 20 min, cool to 50°C, add isophorone diisocyanate (0.2 times the mass of PTHF), add DY-20 (0.05 times the mass of PTHF), heat to 80°C for reaction for 5 h, cool to 55°C, add acetone (0.15 times the mass of PTHF), Add 0.2 times the mass of butanediol of the polytetrahydrofuran, add 0.3 times the mass of DMPA of the polytetrahydrofuran, heat to 65°C for reaction for 3 hours, cool to 40°C, add 0.2 times the mass of triethylamine of the polytetrahydrofuran, add 5 times the mass of deionized water of the polytetrahydrofuran under stirring at 800r / min, continue stirring for 15 minutes, add 0.05 times the mass of IPDA of the polytetrahydrofuran, and disperse for 2 hours with a 22KW high-speed disperser to obtain an aqueous polyurethane solution;

[0053] (5) mixing the aqueous polyurethane solution and KH-570 at a mass ratio of 10:1, and stirring at 300 r / min for 60 min to obtain a modified aqueous polyurethane;

[0054] (6) mixing diphenylsilanediol and p-tolylsilane in a mass ratio of 2:1, and stirring at 300 r / min for 60 min to prepare an organosilicon solution;

[0055] (7) The modified waterborne polyurethane solution and the modified nano-silica solution were mixed in a mass ratio of 15:1 to obtain a mixed solution, which was stirred at 300 r / min for 45 min, and a silicone solution 0.3 times the mass of the mixed solution was added. The mixture was heated to 50° C. and reacted for 2 h, and then naturally cooled to room temperature to obtain a moisture-proof waterborne nano-high-efficiency sealant.

[0056] Comparative Example 1

[0057] The difference between Comparative Example 1 and Example 1 is that there is no step (2), and step (3) is changed to: adding silicon dioxide powder with a particle size of 80 nm to 2-hydroxy-3-fluorobenzonitrile with a mass that is 3 times that of the silicon dioxide powder, heating to 50° C., stirring at 600 r / min for 8 h, and naturally cooling to room temperature to obtain modified nano-silica sol; the remaining steps are the same as in Example 1.

[0058] Comparative Example 2

[0059] The difference between Comparative Example 2 and Example 1 is that there is no step (3), and step (7) is changed to: adding hydroxylated silica powder to deionized water with a mass of 3 times that of the hydroxylated silica powder, stirring at 600 r / min for 8 h to obtain hydroxylated silica sol, mixing the modified aqueous polyurethane solution and the hydroxylated silica solution in a mass ratio of 10:1 to obtain a mixed solution, stirring at 200 r / min for 30 min, adding 0.1 times the mass of the mixed solution of organic silicon solution, heating to 40°C for reaction for 1 h, and naturally cooling to room temperature to obtain a moisture-proof water-based nano high-efficiency sealant; the remaining steps are the same as those in Example 2.

[0060] Comparative Example 3

[0061] The difference between Comparative Example 3 and Example 1 is that there is no step (5), and step (7) is changed to: the aqueous polyurethane solution and the modified nano-silica solution are mixed in a mass ratio of 10:1 to obtain a mixed solution, stirred at 200 r / min for 30 min, 0.1 times the mass of the mixed solution of the organic silicon solution is added, the temperature is raised to 40°C and reacted for 1 h, and then naturally cooled to room temperature to obtain a moisture-proof water-based nano high-efficiency sealant; the remaining steps are the same as those in Example 1.

[0062] Comparative Example 4

[0063] The difference between Comparative Example 3 and Example 1 is that there is no step (6), and step (7) is changed to mixing the modified aqueous polyurethane solution and the modified nano-silicon dioxide solution in a mass ratio of 10:1 to obtain a mixed solution, and stirring at 200 r / min for 30 min to obtain a moisture-proof water-based nano-high-efficiency sealant; the remaining steps are the same as Example 1.

[0064] Effect example

[0065] Tables 1 and 2 below show the performance analysis results of moisture-proof water-based nano high-efficiency sealants using Examples 1 to 3 of the present invention and Comparative Examples 1 to xx.

[0066] Table 1

[0067]

[0068]

[0069] Table 2

[0070]

[0071] From the comparison of the experimental data of Examples 1, 2, and 3 with Comparative Example 1, it can be found that if the activity of the hydroxyl groups on the surface of the nano-silica is not activated by ultraviolet rays and ozone, when 2-hydroxy-3-fluorobenzonitrile is added, the hydroxyl groups on it and the surface active hydroxyl groups of the nano-silica will undergo a condensation reaction, and the activity of the hydroxyl groups will be reduced, and the anti-ultraviolet effect will be reduced; from the comparison of the experimental data of Examples 1, 2, and 3 with Comparative Example 2, it can be found that if 2-hydroxy-3-fluorobenzonitrile is not added, even if the hydroxyl groups on the surface of the nano-silica are activated, the nitrogen-nitrogen triple bond cannot be introduced, and the sealant cannot have the anti-ultraviolet effect. Line performance; from the comparison of the experimental data of Examples 1, 2, and 3 with Comparative Example 3, it can be found that without using KH-570 silane coupling agent to modify the waterborne polyurethane, it is impossible to combine with diphenylsilanediol and p-tolylsilane for non-covalent interaction, and the anti-aging ability of the sealant cannot be improved; from the comparison of the experimental data of Examples 1, 2, and 3 with Comparative Example 4, it can be found that without adding diphenylsilanediol and p-tolylsilane, even if KH-570 silane coupling agent is added, it is impossible to combine with diphenylsilanediol and p-tolylsilane for non-covalent interaction, and the anti-aging ability of the sealant cannot be improved.

[0072] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations within the meaning and scope of the equivalent elements of the claims be included in the invention. Any marking in a claim should not be considered as limiting the claim to which it relates.

Claims

1. A moisture-proof water-based nano high-efficiency sealant, characterized in that: The moisture-proof water-based nanometer high-efficiency sealant is prepared by adding modified nanometer silicon dioxide, diphenylsilanediol and p-tolylsilane into modified water-based polyurethane.

2. A moisture-proof water-based nano high-efficiency sealant according to claim 1, characterized in that: The modified nano silicon dioxide is prepared by activating the hydroxyl activity on the surface of the nano silicon dioxide using ultraviolet rays and ozone, and then adding 2-hydroxy-3-fluorobenzonitrile.

3. The moisture-proof water-based nano high-efficiency sealant according to claim 1, characterized in that: The modified waterborne polyurethane is prepared by adding KH-570 silane coupling agent into waterborne polyurethane.

4. A method for preparing a moisture-proof water-based nano high-efficiency sealant, characterized in that: The method comprises the following preparation steps: (1) immersing silica powder with a particle size of 80 to 100 nm in an acetone solution, ultrasonically treating at 30 to 40 kHz for 30 to 40 minutes, filtering, taking out the solid, washing it with deionized water for 2 to 3 times, drying it at room temperature, 1.72 MPa and nitrogen protection for 1 to 2 hours, placing it in a piranha solution with a mass 4 to 5 times that of the silica powder for 30 to 45 minutes, filtering, taking out the solid, washing it with deionized water for 2 to 3 times, drying it at room temperature, 1.72 MPa and nitrogen protection for 1 to 2 hours, and then irradiating it with ultraviolet light at room temperature, 1.35 MPa and ozone protection to obtain hydroxylated silica powder; (2) adding hydroxylated silica powder to 2-hydroxy-3-fluorobenzonitrile with a mass of 3 to 6 times that of the hydroxylated silica powder, heating to 50 to 60° C., stirring at 600 to 800 r / min for 8 to 10 hours, and naturally cooling to room temperature to obtain a modified nano-silica sol; (3) Mix polytetrahydrofuran and TMP in a mass ratio of 50 to 60:1, heat to 100 to 120°C, evacuate to -0.05 to -0.1 MPa, dehydrate for 10 to 20 minutes, cool to 40 to 50°C, add isophorone diisocyanate at a mass of 0.1 to 0.2 times that of polytetrahydrofuran, add DY-20 at a mass of 0.01 to 0.05 times that of polytetrahydrofuran, heat to 70 to 80°C, react for 3 to 5 hours, cool to 50 to 55°C, add propylene glycol at a mass of 0.05 to 0.15 times that of polytetrahydrofuran, and add propylene glycol at a mass of 0.05 to 0.15 times that of polytetrahydrofuran. ketone, add butanediol in an amount of 0.1 to 0.2 times the mass of polytetrahydrofuran, add DMPA in an amount of 0.2 to 0.3 times the mass of polytetrahydrofuran, heat to 60 to 65°C for reaction for 2 to 3 hours, cool to 40°C, add triethylamine in an amount of 0.1 to 0.2 times the mass of polytetrahydrofuran, add deionized water in an amount of 3 to 5 times the mass of polytetrahydrofuran under stirring at 700 to 800 r / min, continue stirring for 10 to 15 minutes, add IPDA in an amount of 0.02 to 0.05 times the mass of polytetrahydrofuran, and disperse at high speed to obtain an aqueous polyurethane solution; (4) The modified waterborne polyurethane solution and the modified nano-silica solution are mixed in a mass ratio of 10 to 15:1 to obtain a mixed solution, stirred at 200 to 300 r / min for 30 to 45 min, 0.1 to 0.3 times the mass of the mixed solution of the organic silicon solution is added, the mixture is heated to 40 to 50° C. and reacted for 1 to 2 h, and then naturally cooled to room temperature to obtain a moisture-proof waterborne nano-high-efficiency sealant.

5. The method for preparing a moisture-proof water-based nano high-efficiency sealant according to claim 4, characterized in that: The piranha solution in step (1) is prepared by mixing concentrated sulfuric acid and hydrogen peroxide in a volume ratio of 2 to 2.5:

1.

6. The method for preparing a moisture-proof water-based nano high-efficiency sealant according to claim 4, characterized in that: The ultraviolet light irradiation in step (2) is to receive ultraviolet light with wavelengths of 185 nm and 254 nm for 3 to 6 hours.

7. The method for preparing a moisture-proof water-based nano high-efficiency sealant according to claim 4, characterized in that: The high-speed dispersion in step (3) is performed by using a 22KW high-speed disperser for 1 to 2 hours.

8. The method for preparing a moisture-proof water-based nano high-efficiency sealant according to claim 4, characterized in that: The molecular weight of the polytetrahydrofuran in the step (3) is 2000-3000.

9. The method for preparing a moisture-proof water-based nano high-efficiency sealant according to claim 4, characterized in that: The modified waterborne polyurethane in step (4) is prepared by mixing the waterborne polyurethane solution and KH-570 at a mass ratio of 8 to 10:1, and stirring at 200 to 300 r / min for 30 to 60 minutes.

10. The method for preparing a moisture-proof water-based nano high-efficiency sealant according to claim 4, characterized in that: The organosilicon solution in step (4) is prepared by mixing diphenylsilanediol and p-tolylsilane in a mass ratio of 1 to 2:1 and stirring at 200 to 300 r / min for 30 to 60 minutes.

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