Waterproof coating based on cyanate ester formula and preparation method thereof

Abstract

The invention relates to the technical field of waterproof coatings, and discloses a waterproof coating based on a cyanate ester formula and a preparation method of the waterproof coating, polyurethane is used as film-forming resin to prepare a reflective thermal insulation coating, and particularly, hexamethylene diisocyanate and dicyclohexylmethane diisocyanate have stronger adhesive force, good high temperature resistance and low temperature resistance under a specific proportion, and have better thermal insulation performance. The reflective heat-insulating coating has the advantages of good mechanical properties and good flexibility, can overcome the defects of polymer emulsion, improves the effective service life of the reflective heat-insulating coating, can give consideration to the mechanical properties and self-repairing efficiency of waterproof materials, reduces the cost, does not generate harmful gases, is simple in manufacturing process, and saves the manpower and equipment cost.

Description

Technical Field

[0001] The invention relates to the technical field of waterproof coatings and discloses a waterproof coating based on a cyanate ester formula and a preparation method thereof. Background Art

[0002] With the progress of the times, the demand for multifunctional coatings has gradually increased, such as antibacterial waterproof coatings, flame retardant waterproof coatings, aging-resistant waterproof coatings and anti-corrosion waterproof coatings. Among them, for flame retardant waterproof coatings, flame retardants are usually added to waterproof coatings to achieve fireproof functions. In the research and development of flame retardant waterproof coatings, halogen flame retardants were widely used in the early stage, which have the advantages of high flame retardant efficiency, small dosage, and economical affordability. However, halogen flame retardants will release a large amount of harmful gases when burned, which endangers human health and environmental safety. In order to solve the problem of the safety of halogen flame retardants, researchers have developed inorganic flame retardants, such as aluminum hydroxide, magnesium hydroxide, expanded graphite, etc.

[0003] However, the flame retardant effect of inorganic flame retardants needs to be improved. In addition, excessive use of inorganic flame retardants in the waterproof coating composition will also affect the mechanical properties of the waterproof coating composition. Therefore, how to provide a waterproof coating composition with excellent flame retardant properties is a technical problem that needs to be urgently solved by technical personnel in this field. Summary of the invention

[0004] The following is a summary of some aspects of the present invention, but is not intended to limit the present invention. When there is a discrepancy between the disclosure of this specification and the referenced document, the disclosure of this specification shall prevail.

[0005] The present invention aims to overcome at least one defect (shortcoming) of the above-mentioned prior art and provide a polyurethane waterproof coating that can take into account both the mechanical properties and self-repair efficiency of waterproof materials, increase the effective service life of the reflective thermal insulation coating, and has low cost and does not produce harmful gases.

[0006] A waterproof coating based on a cyanate formula specifically comprises the following components in parts by weight: 7-15 parts by weight of diisocyanate, 10-30 parts by weight of diol, 10-60 parts by weight of polyether triol, 0.05-1.0 parts by weight of catalyst, 1.0-5.0 parts by weight of chain extender, 15-30 parts by weight of plasticizer, 10-30 parts by weight of solvent, 2-5 parts by weight of near-infrared reflecting titanium dioxide, and 5-15 parts by weight of thermal insulation filler.

[0007] Furthermore, the waterproof coating includes the following components in parts by weight: 12 parts by weight of diisocyanate, 24 parts by weight of diol, 11 parts by weight of polyether triol, 1.0 parts by weight of catalyst, 3.0 parts by weight of chain extender, 20 parts by weight of plasticizer, 20 parts by weight of solvent, 3 parts by weight of near-infrared reflecting titanium dioxide, and 6 parts by weight of thermal insulation filler.

[0008] Furthermore, the diisocyanate is selected from one or more of toluene diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, 4,4'-diisocyanate dicyclohexylmethane, dicyclohexylmethane diisocyanate, 1,4-cyclohexane diisocyanate, and cyclohexane dimethylene diisocyanate.

[0009] Furthermore, the diisocyanate is hexamethylene diisocyanate and dicyclohexylmethane diisocyanate, wherein the mass ratio of hexamethylene diisocyanate to dicyclohexylmethane diisocyanate is 2-5:1, and more preferably the mass ratio of hexamethylene diisocyanate to dicyclohexylmethane diisocyanate is 3:1.

[0010] Furthermore, the diol is selected from one or more of polypropylene glycol, polytetramethylene glycol, polyester glycol, ethylene glycol, propylene glycol, 1,4-butanediol, and 1,8-octanediol.

[0011] Furthermore, the diol is selected from polypropylene glycol and 1,4-butanediol, wherein the mass ratio of polypropylene glycol to 1,4-butanediol is 2 to 3:1, and more preferably the mass ratio of polypropylene glycol to 1,4-butanediol is 2:1.

[0012] Furthermore, the polyether triol is selected from one or more of Dow VORANOL 4701, Dow VORANOL 4702, Bluestar Dongda EP-330N, Bluestar Dongda EP-3600, Bluestar Dongda 10LD76E, and Bluestar Dongda 10LD83E.

[0013] Furthermore, the polyether triol is Bluestar Dongda EP-3600, and the number average molecular weight is 6000.

[0014] Furthermore, the catalyst is selected from one or more of dibutyltin dilaurate, stannous octoate, dibutyltin diacetate, triethylamine, and triethylenediamine.

[0015] Furthermore, the catalyst is selected from dibutyltin diacetate.

[0016] Furthermore, the chain extender is selected from one or more of trimethylolpropane, ethylene glycol, propylene glycol, polyethylene glycol, and 1,4-butanediol.

[0017] Furthermore, the chain extender is polyethylene glycol and 1,4-butanediol, wherein the mass ratio of polyethylene glycol to 1,4-butanediol is 2 to 3:1, and more preferably the mass ratio of polyethylene glycol to 1,4-butanediol is 2:1.

[0018] Furthermore, the plasticizer is selected from one or more of chlorinated paraffin, dibutyl phthalate, acetyl tributyl citrate, epoxidized soybean oil, tributyl phosphate, and triethyl phosphate.

[0019] Furthermore, the plasticizer is selected from one or more of epoxidized soybean oil, tributyl phosphate, and triethyl phosphate, preferably epoxidized soybean oil.

[0020] Furthermore, the solvent is selected from one or more of acetone, butanone, tetrahydrofuran, ethyl acetate, propylene glycol methyl ether acetate, and butyl acetate; the near-infrared reflecting titanium dioxide is nanometer-grade; and the thermal insulation filler is selected from one or more of hollow glass microspheres, hollow ceramic microspheres, and silica aerogel.

[0021] Furthermore, the solvent is ethyl acetate; and the thermal insulation filler is silica aerogel.

[0022] A method for preparing the above waterproof coating, characterized in that it comprises the following components in parts by weight:

[0023] S1: Evenly mix the diol, polyether triol, plasticizer, near-infrared reflective titanium dioxide and thermal insulation filler, stir and heat up to 90-110°C, and dehydrate under vacuum conditions of -0.1MPa to -0.05MPa for 2-3h;

[0024] S2: Cool down to 70-80°C, add diisocyanate, catalyst, chain extender and solvent under stirring, and react for about 0.5-1h;

[0025] S3: Cooling to 50-70°C, adding catalyst and solvent under stirring, reacting for about 10-30 minutes, degassing and discharging; the amount of the catalyst added each time is 1 / 2 of the total amount, and the amount of the solvent added each time is 1 / 2 of the total amount.

[0026] Furthermore, a method for preparing a polyurethane waterproof coating containing diisocyanate is characterized by comprising the following components in parts by weight:

[0027] S1: polypropylene glycol, 1,4-butanediol, polyether triol, epoxy soybean oil, near-infrared reflective titanium dioxide, and silica aerogel are uniformly mixed, stirred and heated to 90-110°C, and dehydrated under vacuum conditions of -0.1MPa to -0.05MPa for 2-3h;

[0028] S2: Cool down to 70-80°C, add hexamethylene diisocyanate, dicyclohexylmethane diisocyanate, dibutyltin diacetate, 1,4-butanediol, polyethylene glycol and ethyl acetate under stirring, and react for about 0.5-1h;

[0029] S3: Cooling to 50-70° C., adding dibutyltin diacetate and ethyl acetate under stirring, reacting for about 10-30 minutes, and degassing and discharging the material; the amount of dibutyltin diacetate added each time is 1 / 2 of the total amount, and the amount of ethyl acetate added each time is 1 / 2 of the total amount.

[0030] The second aspect of the present invention provides a polyurethane waterproof coating containing diisocyanate prepared by the method described in the first aspect.

[0031] The third aspect of the present invention provides the use of the polyurethane waterproof coating containing diisocyanate described in the second aspect in waterproof materials.

[0032] Beneficial technical effects of the present invention

[0033] Compared with the prior art, the technical solution of the present invention has the following advantages:

[0034] 1. The prior art mainly uses acrylic emulsion or modified acrylic emulsion as a film-forming resin to prepare reflective thermal insulation coatings. The present invention uses polyurethane as a film-forming resin to prepare reflective thermal insulation coatings, especially hexamethylene diisocyanate and dicyclohexylmethane diisocyanate at a specific ratio, which has stronger adhesion, good temperature resistance, good mechanical properties, and good flexibility, and can overcome the shortcomings of polymer emulsions and increase the effective service life of the coating.

[0035] 2. The present invention provides a polyurethane waterproof coating that can take into account both the mechanical properties and self-repair efficiency of waterproof materials, increase the effective service life of reflective thermal insulation coatings, and has low cost and does not produce harmful gases. The preparation method of the present invention has a simple process, is easy to operate, and saves manpower and equipment costs. DETAILED DESCRIPTION

[0036] Unless otherwise indicated or there is an obvious conflict in the context, all technical and scientific terms used herein have the same meaning as those generally understood by those of ordinary skill in the art to which the invention belongs. If there is a conflict, the definitions provided in the application shall prevail. When a trade name appears in this article, it is intended to refer to the corresponding commodity or its active ingredient. All patents, published patent applications and publications cited herein are incorporated herein by reference.

[0037] Embodiment 1:

[0038] A polyurethane waterproof coating containing diisocyanate, comprising the following components in parts by weight: 9 parts by weight of hexamethylene diisocyanate, 3 parts by weight of dicyclohexylmethane diisocyanate, 16 parts by weight of polypropylene glycol, 8 parts by weight of 1,4-butanediol, 11 parts by weight of polyether triol Bluestar Dongda EP-3600, 1.0 parts by weight of dibutyltin diacetate, 1 part by weight of 1,4-butanediol, 2 parts by weight of polyethylene glycol, 20 parts by weight of epoxy soybean oil, 20 parts by weight of ethyl acetate, 3 parts of near-infrared reflective titanium dioxide, and 6 parts by weight of silica aerogel;

[0039] The polyurethane waterproof coating of this embodiment is prepared in a closed reactor, and the specific method is as follows:

[0040] S1: polypropylene glycol, 1,4-butanediol, polyether triol, epoxy soybean oil, near-infrared reflective titanium dioxide, and silica aerogel were uniformly mixed, heated to 100°C with stirring, and dehydrated for 2 hours under a vacuum condition of -0.08 MPa;

[0041] S2: Cool down to 75°C, add hexamethylene diisocyanate, dicyclohexylmethane diisocyanate, dibutyltin diacetate, 1,4-butanediol, polyethylene glycol and ethyl acetate under stirring, and react for about 0.5h;

[0042] S3: Cooling to 60° C., adding dibutyltin diacetate and ethyl acetate under stirring, reacting for about 20 minutes, and degassing and discharging the material; the amount of dibutyltin diacetate added each time is 1 / 2 of the total amount, and the amount of ethyl acetate added each time is 1 / 2 of the total amount.

[0043] Embodiment 2:

[0044] A polyurethane waterproof coating containing diisocyanate, comprising the following components in parts by weight: 12 parts by weight of hexamethylene diisocyanate, 24 parts by weight of polypropylene glycol, 11 parts by weight of polyether triol Bluestar Dongda EP-3600, 1.0 parts by weight of dibutyltin diacetate, 3 parts by weight of 1,4-butanediol, 20 parts by weight of epoxy soybean oil, 20 parts by weight of ethyl acetate, 3 parts by weight of near-infrared reflective titanium dioxide, and 6 parts by weight of silica aerogel;

[0045] The polyurethane waterproof coating of this embodiment is prepared in a closed reactor, and the specific method is as follows:

[0046] S1: polypropylene glycol, polyether triol, epoxy soybean oil, near-infrared reflective titanium dioxide and silica aerogel were uniformly mixed, heated to 90°C with stirring, and dehydrated for 2 h under a vacuum condition of -0.07 MPa;

[0047] S2: Cool down to 70°C, add hexamethylene diisocyanate, dibutyltin diacetate, 1,4-butanediol and ethyl acetate under stirring, and react for about 0.5h;

[0048] S3: Cooling to 55° C., adding dibutyltin diacetate and ethyl acetate under stirring, reacting for about 20 minutes, and degassing and discharging the material; the amount of dibutyltin diacetate added each time is 1 / 2 of the total amount, and the amount of ethyl acetate added each time is 1 / 2 of the total amount.

[0049] Embodiment 3:

[0050] A polyurethane waterproof coating containing diisocyanate, comprising the following components in parts by weight: 12 parts by weight of dicyclohexylmethane diisocyanate, 24 parts by weight of 1,4-butanediol, 11 parts by weight of polyether triol Bluestar Dongda EP-3600, 1.0 parts by weight of dibutyltin diacetate, 3 parts by weight of polyethylene glycol, 20 parts by weight of epoxy soybean oil, 20 parts by weight of ethyl acetate, 3 parts of near-infrared reflective titanium dioxide, and 6 parts by weight of silica aerogel;

[0051] The polyurethane waterproof coating of this embodiment is prepared in a closed reactor, and the specific method is as follows:

[0052] S1: 1,4-butanediol, polyether triol, epoxy soybean oil, near-infrared reflective titanium dioxide, and silica aerogel were uniformly mixed, heated to 110°C with stirring, and dehydrated for 2 hours under a vacuum condition of -0.1 MPa;

[0053] S2: Cool down to 80°C, add dicyclohexylmethane diisocyanate, dibutyltin diacetate, polyethylene glycol and ethyl acetate under stirring, and react for about 0.5h;

[0054] S3: Cooling to 70° C., adding dibutyltin diacetate and ethyl acetate under stirring, reacting for about 20 minutes, and degassing and discharging the material; the amount of dibutyltin diacetate added each time is 1 / 2 of the total amount, and the amount of ethyl acetate added each time is 1 / 2 of the total amount.

[0055] Embodiment 4:

[0056] A polyurethane waterproof coating containing diisocyanate, comprising the following components in parts by weight: 12 parts by weight of isophorone diisocyanate, 24 parts by weight of ethylene glycol, 11 parts by weight of polyether triol Bluestar Dongda EP-330N, 1.0 parts by weight of stannous octoate, 3 parts by weight of propylene glycol, 20 parts by weight of tributyl phosphate, 20 parts by weight of propylene glycol methyl ether acetate, 3 parts of near-infrared reflecting titanium dioxide, and 6 parts by weight of hollow glass microspheres;

[0057] The polyurethane waterproof coating of this embodiment is prepared in a closed reactor, and the specific method is as follows:

[0058] S1: Ethylene glycol, polyether triol, tributyl phosphate, near-infrared reflective titanium dioxide and hollow glass microspheres were uniformly mixed, heated to 100°C with stirring, and dehydrated for 2 h under a vacuum condition of -0.05 MPa;

[0059] S2: Cool down to 75°C, add isophorone diisocyanate, stannous octoate, propylene glycol and propylene glycol methyl ether acetate under stirring, and react for about 0.5h;

[0060] S3: Cooling to 60° C., adding stannous octoate and propylene glycol methyl ether acetate under stirring, reacting for about 20 minutes, and degassing and discharging the material; the amount of stannous octoate added each time is 1 / 2 of the total amount, and the amount of propylene glycol methyl ether acetate added each time is 1 / 2 of the total amount.

[0061] Embodiment 5:

[0062] A polyurethane waterproof coating containing diisocyanate, comprising the following components in parts by weight: 9 parts by weight of 1,4-cyclohexane diisocyanate, 3 parts by weight of cyclohexane dimethylene diisocyanate, 16 parts by weight of polyester diol, 8 parts by weight of 1,4-butanediol, 11 parts by weight of polyether triol Bluestar Dongda 10LD76E, 1.0 parts by weight of triethylene diamine, 2 parts by weight of polyethylene glycol, 1 part by weight of propylene glycol, 20 parts by weight of dibutyl phthalate, 20 parts by weight of ethyl acetate, 3 parts of near-infrared reflective titanium dioxide, and 6 parts by weight of hollow glass microspheres;

[0063] The polyurethane waterproof coating of this embodiment is prepared in a closed reactor, and the specific method is as follows:

[0064] S1: Evenly mix polyester diol, 1,4-butanediol, polyether triol, dibutyl phthalate, near-infrared reflective titanium dioxide, and hollow glass microspheres, stir and heat to 100°C, and dehydrate under vacuum conditions of -0.07 MPa for 2 h;

[0065] S2: Cool down to 75°C, add 1,4-cyclohexane diisocyanate, cyclohexane dimethylene diisocyanate, triethylene diamine, polyethylene glycol, propylene glycol, and ethyl acetate under stirring, and react for about 0.5h;

[0066] S3: Cooling to 65°C, adding triethylenediamine and ethyl acetate under stirring, reacting for about 20 minutes, degassing and discharging the material; the amount of triethylenediamine added each time is 1 / 2 of the total amount, and the amount of ethyl acetate added each time is 1 / 2 of the total amount.

[0067] Embodiment 6:

[0068] A polyurethane waterproof coating containing diisocyanate, comprising the following components in parts by weight: 20 parts by weight of isophorone diisocyanate, 5 parts by weight of ethylene glycol, 5 parts by weight of polyether triol Bluestar Dongda EP-330N, 2.0 parts by weight of stannous octoate, 8 parts by weight of propylene glycol, 10 parts by weight of tributyl phosphate, 40 parts by weight of propylene glycol methyl ether acetate, 6 parts of near-infrared reflecting titanium dioxide, and 4 parts by weight of hollow glass microspheres;

[0069] The polyurethane waterproof coating of this embodiment is prepared in a closed reactor, and the specific method is as follows:

[0070] S1: Ethylene glycol, polyether triol, tributyl phosphate, near-infrared reflective titanium dioxide and hollow glass microspheres were uniformly mixed, heated to 100°C with stirring, and dehydrated for 2 h under a vacuum condition of -0.05 MPa;

[0071] S2: Cool down to 75°C, add isophorone diisocyanate, stannous octoate, propylene glycol and propylene glycol methyl ether acetate under stirring, and react for about 0.5h;

[0072] S3: Cooling to 60° C., adding stannous octoate and propylene glycol methyl ether acetate under stirring, reacting for about 20 minutes, and degassing and discharging the material; the amount of stannous octoate added each time is 1 / 2 of the total amount, and the amount of propylene glycol methyl ether acetate added each time is 1 / 2 of the total amount.

[0073] Embodiment 7:

[0074] A polyurethane waterproof coating containing diisocyanate, comprising the following components in parts by weight: 9 parts by weight of 1,4-cyclohexane diisocyanate, 3 parts by weight of cyclohexane dimethylene diisocyanate, 16 parts by weight of polyester diol, 8 parts by weight of 1,4-butanediol, 11 parts by weight of polyether triol Bluestar Dongda 10LD76E, 1.0 parts by weight of triethylene diamine, 2 parts by weight of polyethylene glycol, 1 part by weight of propylene glycol, 20 parts by weight of dibutyl phthalate, 20 parts by weight of ethyl acetate, 3 parts of near-infrared reflective titanium dioxide, and 6 parts by weight of hollow glass microspheres;

[0075] The polyurethane waterproof coating of this embodiment is prepared in a closed reactor, and the specific method is as follows:

[0076] S1: Evenly mix polyester diol, 1,4-butanediol, polyether triol, dibutyl phthalate, near-infrared reflective titanium dioxide, and hollow glass microspheres, stir and heat to 80°C, and dehydrate under vacuum conditions of -0.01 MPa for 2 h;

[0077] S2: Cool down to 65°C, add 1,4-cyclohexane diisocyanate, cyclohexane dimethylene diisocyanate, triethylene diamine, polyethylene glycol, propylene glycol, and ethyl acetate under stirring, and react for about 0.5h;

[0078] S3: Cooling to 55° C., adding triethylenediamine and ethyl acetate under stirring, reacting for about 20 minutes, and degassing and discharging the material; the amount of triethylenediamine added each time is 1 / 2 of the total amount, and the amount of ethyl acetate added each time is 1 / 2 of the total amount.

[0079] Embodiment 8:

[0080] A polyurethane waterproof coating containing diisocyanate, comprising the following components in parts by weight: 20 parts by weight of isophorone diisocyanate, 5 parts by weight of ethylene glycol, 5 parts by weight of polyether triol Bluestar Dongda EP-330N, 2.0 parts by weight of stannous octoate, 8 parts by weight of propylene glycol, 10 parts by weight of tributyl phosphate, 40 parts by weight of propylene glycol methyl ether acetate, 6 parts of near-infrared reflecting titanium dioxide, and 4 parts by weight of hollow glass microspheres;

[0081] The polyurethane waterproof coating of this embodiment is prepared in a closed reactor, and the specific method is as follows:

[0082] S1: Ethylene glycol, polyether triol, tributyl phosphate, near-infrared reflective titanium dioxide and hollow glass microspheres were uniformly mixed, heated to 120°C with stirring, and dehydrated for 2 h under a vacuum condition of -0.05 MPa;

[0083] S2: Cool down to 85°C, add isophorone diisocyanate, stannous octoate, propylene glycol and propylene glycol methyl ether acetate under stirring, and react for about 0.5h;

[0084] S3: Cooling to 80° C., adding stannous octoate and propylene glycol methyl ether acetate under stirring, reacting for about 20 minutes, and degassing and discharging the material; the amount of stannous octoate added each time is 1 / 2 of the total amount, and the amount of propylene glycol methyl ether acetate added each time is 1 / 2 of the total amount.

[0085] Embodiment 9:

[0086] Under the conditions of 23±2°C and relative humidity of 50%, the polyurethane waterproof coating prepared in the embodiment was coated on the mold frame, and the coating was performed according to the method of national standard GB / T 19250-2013, and the coating thickness was controlled to be 1.5mm±0.2mm. The tensile strength, elongation and self-repairing efficiency of the polyurethane waterproof coating were tested. The specific test results are shown in Table 1.

[0087] The specific coating process is as follows: weigh the required amount of sample under standard test conditions, apply it to the specified thickness three times (each time with an interval of 2 hours), wait 5 minutes after coating, scrape off the bubbles on the surface and smooth the surface, cure the prepared coating under standard test conditions for 96 hours, then demold, turn the coating over and cure it under standard test conditions for 72 hours.

[0088] The tensile strength and elongation are tested according to the method specified in Chapter 9 of GB / T16777-2008;

[0089] The test method of self-healing efficiency is as follows: the coating film prepared above is cut in the middle with a knife, and then the two cross sections are bonded together. After the bonded sample is placed at 23℃±2℃ for 24 hours, the test specimen is prepared according to the method specified in GB / T19250-2013 and GB / T16777-2008, and the tensile strength of the self-healing sample is tested, and the self-healing efficiency is calculated;

[0090] The calculation formula of the self-repairing efficiency is: (tensile strength of the sample after self-repairing / initial tensile strength of the sample)×100%.

[0091] Table 1

[0092] Tensile strength, MPa Elongation, % Self-repair efficiency, % Example 1 8.6 719 95 Example 2 8.0 657 92 Example 3 7.8 592 93 Example 4 7.7 587 91 Example 5 7.6 569 90 Example 6 4.7 392 75 Example 7 4.8 377 69 Example 8 4.5 365 65

[0093] It can be seen from the results in Table 1 that the polyurethane waterproof coating prepared by the method provided by the present invention can maintain excellent mechanical properties while also having excellent self-repair efficiency.

[0094] The above is a description of a specific embodiment of the present invention. It should be understood that the present invention is not limited to the above embodiment, and the above embodiment and description are only for illustrating the principle of the present invention.

[0095] Those skilled in the art may make various non-substantial changes and improvements to the present invention without departing from the concept of the present invention, all of which fall within the scope of protection claimed by the present invention.

Claims

1. A waterproof coating based on a cyanate ester formulation, characterized in that: The invention comprises the following components in parts by weight: 7-15 parts by weight of diisocyanate, 10-30 parts by weight of diol, 10-60 parts by weight of polyether triol, 0.05-1.0 parts by weight of catalyst, 1.0-5.0 parts by weight of chain extender, 15-30 parts by weight of plasticizer, 10-30 parts by weight of solvent, 2-5 parts by weight of near-infrared reflecting titanium dioxide and 5-15 parts by weight of thermal insulation filler.

2. The waterproof coating according to claim 1, characterized in that: The diisocyanate is selected from one or more of toluene diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, 4,4'-diisocyanate dicyclohexylmethane, dicyclohexylmethane diisocyanate, 1,4-cyclohexane diisocyanate, and cyclohexane dimethylene diisocyanate.

3. The waterproof coating according to claim 1, characterized in that: The diol is selected from one or more of polypropylene glycol, polytetramethylene glycol, polyester glycol, ethylene glycol, propylene glycol, 1,4-butanediol, and 1,8-octanediol.

4. The waterproof coating according to claim 1, characterized in that: The polyether triol is selected from one or more of Dow VORANOL 4701, Dow VORANOL 4702, Bluestar Dongda EP-330N, Bluestar Dongda EP-3600, Bluestar Dongda 10LD76E, and Bluestar Dongda 10LD83E.

5. The waterproof coating according to claim 1, characterized in that: The catalyst is selected from one or more of dibutyltin dilaurate, stannous octoate, dibutyltin diacetate, triethylamine, and triethylenediamine.

6. The waterproof coating according to claim 1, characterized in that: The chain extender is selected from one or more of trimethylolpropane, ethylene glycol, propylene glycol, polyethylene glycol, and 1,4-butanediol.

7. The waterproof coating according to claim 1, characterized in that: The plasticizer is selected from one or more of chlorinated paraffin, dibutyl phthalate, acetyl tributyl citrate, epoxidized soybean oil, tributyl phosphate, and triethyl phosphate.

8. The waterproof coating according to claim 1, characterized in that: The solvent is selected from one or more of acetone, butanone, tetrahydrofuran, ethyl acetate, propylene glycol methyl ether acetate, and butyl acetate; the near-infrared reflective titanium dioxide is nanometer-grade; and the thermal insulation filler is selected from one or more of hollow glass microspheres, hollow ceramic microspheres, and silica aerogel.

9. A method for preparing the waterproof coating according to any one of claims 1 to 8, characterized in that: The composition comprises the following components by weight: S1: Evenly mix the diol, polyether triol, plasticizer, near-infrared reflective titanium dioxide and thermal insulation filler, stir and heat up to 90-110°C, and dehydrate under vacuum conditions of -0.1MPa to -0.05MPa for 2-3h; S2: Cool down to 70-80°C, add diisocyanate, catalyst, chain extender and solvent under stirring, and react for about 0.5-1h; S3: Cooling to 50-70°C, adding catalyst and solvent under stirring, reacting for about 10-30 minutes, degassing and discharging; the amount of the catalyst added each time is 1 / 2 of the total amount, and the amount of the solvent added each time is 1 / 2 of the total amount.