Polyurethane waterproof coating containing diisocyanate and preparation method thereof

Abstract

The invention relates to the technical field of waterproof coatings, and discloses a polyurethane waterproof coating containing diisocyanate as well as a preparation method and application thereof, and the method comprises the following steps: (1) carrying out first contact reaction on 10-30 parts by weight of dihydric alcohol, 10-60 parts by weight of polyether triol, 7-15 parts by weight of diisocyanate and 0.05-1.0 part by weight of a polymerization catalyst to obtain a first polymer; (2) carrying out a second contact reaction on the first polymer, 1.0-5.0 parts by weight of a chain extender, 15-30 parts by weight of a plasticizer, 10-30 parts by weight of a solvent, 2-5 parts by weight of near-infrared reflection titanium dioxide and 5-15 parts by weight of a thermal insulation filler to obtain a second polymer; and (3) carrying out an emulsion reaction on the second polymer and 80-120 parts by weight of water, and carrying out defoaming treatment on a product obtained after the emulsion reaction. The polyurethane waterproof coating prepared by the method provided by the invention has good mechanical properties and good multi-time self-repairing performance at the same time.

Description

Technical Field

[0001] The invention relates to the technical field of waterproof coatings and discloses a polyurethane waterproof coating containing diisocyanate 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 method for preparing a polyurethane waterproof coating containing diisocyanate, comprising the following components in parts by weight:

[0007] (1) subjecting 10-30 parts by weight of a diol, 10-60 parts by weight of a polyether triol, 7-15 parts by weight of a diisocyanate, and 0.05-1.0 parts by weight of a polymerization catalyst to a first contact reaction to obtain a first polymer;

[0008] (2) subjecting the first polymer, 1.0-5.0 parts by weight of a chain extender, 15-30 parts by weight of a plasticizer, 10-30 parts by weight of a solvent, 2-5 parts by weight of near-infrared reflective titanium dioxide, and 5-15 parts by weight of a thermal insulation filler to a second contact reaction to obtain a second polymer;

[0009] (3) The second polymer is subjected to an emulsification reaction with 80-120 parts by weight of water, and the product obtained after the emulsification reaction is subjected to a degassing treatment.

[0010] Furthermore, a method for preparing a polyurethane waterproof coating containing diisocyanate comprises the following components in parts by weight:

[0011] (1) subjecting 24 parts by weight of a diol, 11 parts by weight of a polyether triol, 12 parts by weight of a diisocyanate, and 1.0 part by weight of a polymerization catalyst to a first contact reaction to obtain a first polymer;

[0012] (2) subjecting the first polymer, 3.0 parts by weight of a chain extender, 20 parts by weight of a plasticizer, 20 parts by weight of a solvent, 3 parts by weight of near-infrared reflective titanium dioxide, and 6 parts by weight of a thermal insulation filler to a second contact reaction to obtain a second polymer;

[0013] (3) The second polymer is subjected to an emulsification reaction with 100 parts by weight of water, and the product obtained after the emulsification reaction is subjected to a degassing treatment.

[0014] Furthermore, the diisocyanate in step 1 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.

[0015] Furthermore, the diisocyanate in step 1 is hexamethylene diisocyanate and dicyclohexylmethane diisocyanate, wherein the mass ratio of hexamethylene diisocyanate to dicyclohexylmethane diisocyanate is 2 to 5:1, and more preferably the mass ratio of hexamethylene diisocyanate to dicyclohexylmethane diisocyanate is 3:1.

[0016] Furthermore, the diol in step 1 is selected from one or more of polypropylene glycol, polytetramethylene glycol, polyester glycol, ethylene glycol, propylene glycol, 1,4-butanediol, and 1,8-octanediol.

[0017] Furthermore, the diol in step 1 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.

[0018] Furthermore, the polyether triol in step 1 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.

[0019] Furthermore, the polyether triol in step 1 is Bluestar Dongda EP-3600, and the number average molecular weight is 6000.

[0020] Furthermore, the polymerization catalyst in step 1 is selected from one or more of dibutyltin dilaurate, stannous octoate, dibutyltin diacetate, triethylamine, and triethylenediamine.

[0021] Furthermore, the polymerization catalyst in step 1 is selected from dibutyltin diacetate.

[0022] Furthermore, the chain extender in step 2 is selected from one or more of trimethylolpropane, ethylene glycol, propylene glycol, polyethylene glycol, and 1,4-butanediol.

[0023] Furthermore, the chain extender in step 2 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.

[0024] Furthermore, the plasticizer in step 2 is selected from one or more of chlorinated paraffin, dibutyl phthalate, acetyl tributyl citrate, epoxidized soybean oil, tributyl phosphate, and triethyl phosphate.

[0025] Furthermore, the plasticizer in step 2 is selected from one or more of epoxidized soybean oil, tributyl phosphate, and triethyl phosphate, preferably epoxidized soybean oil.

[0026] Furthermore, the solvent in step 2 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-scale; and the thermal insulation filler is selected from one or more of hollow glass microspheres, hollow ceramic microspheres, and silica aerogel.

[0027] Furthermore, the solvent in step 2 is ethyl acetate; and the thermal insulation filler is silica aerogel.

[0028] Furthermore, in step 1, the conditions of the first contact reaction include: a temperature of 85-95°C and a vacuum degree of 0.1-0.5 MPa; in step (2), the conditions of the second contact reaction at least include: a temperature of 85-95°C; in step (3), the conditions of the reaction at least include: an initial temperature of 25-35°C, a later temperature of 35-45°C, and a vacuum degree of 0.1-0.5 MPa.

[0029] The second aspect of the present invention provides a polyurethane waterproof coating containing diisocyanate prepared by the method described in the first aspect.

[0030] 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.

[0031] Beneficial technical effects of the present invention

[0032] Compared with the prior art, the technical solution of the present invention has the following advantages:

[0033] 1. The polyurethane waterproof coating prepared by the method provided by the present invention has good multiple self-repairing performance while maintaining good mechanical properties, thereby increasing the effective service life of the coating and having low cost and no harmful gas. The preparation method of the present invention has simple process, easy operation, and saves manpower and equipment costs.

[0034] 2. The present invention uses polyurethane as a film-forming resin to prepare a reflective heat-insulating coating, 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. DETAILED DESCRIPTION

[0035] 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.

[0036] Example 1

[0037] 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, 6 parts by weight of silica aerogel, and 100 parts by weight of water;

[0038] The preparation method of the polyurethane waterproof coating of this embodiment is as follows:

[0039] (1) at room temperature, polypropylene glycol, 1,4-butanediol and polyether triol Bluestar Dongda EP-3600 are contacted and mixed for 20 minutes, the temperature is raised to 90° C., hexamethylene diisocyanate, dicyclohexylmethane diisocyanate and dibutyltin diacetate are added to the product obtained after the contact and mixing to carry out a first contact reaction, the reaction is carried out for 1 to 2 hours, and a dehydration treatment is carried out at a vacuum degree of 0.1 to 0.5 MPa for 1 to 2 hours to obtain a first polymer;

[0040] (2) at 90° C., subjecting the first polymer, 1,4-butanediol, polyethylene glycol, epoxidized soybean oil, ethyl acetate, near-infrared reflective titanium dioxide, and silica aerogel to a second contact reaction for 1 to 2 hours to obtain a second polymer;

[0041] (3) At 30° C., stirring the second polymer and water at 600-800 rpm for 0.5-1 h, and then removing the solvent at 40° C. under vacuum (vacuum degree of 0.1-0.5 MPa) for 40 min to obtain a polyurethane waterproof coating.

[0042] Embodiment 2:

[0043] 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, 6 parts by weight of silica aerogel, and 80 parts by weight of water;

[0044] The preparation method of the polyurethane waterproof coating of this embodiment is as follows:

[0045] (1) At room temperature, polypropylene glycol and polyether triol Bluestar Dongda EP-3600 were contacted and mixed for 20 minutes, and the temperature was raised to 90°C. The product obtained after the contact and mixing was added Hexamethylene diisocyanate Conducting a first contact reaction with dibutyltin diacetate for 1 to 2 hours, and dehydrating for 1 to 2 hours at a vacuum degree of 0.1 to 0.5 MPa to obtain a first polymer;

[0046] (2) at 90° C., subjecting the first polymer, 1,4-butanediol, epoxy soybean oil, ethyl acetate, near-infrared reflective titanium dioxide, and silica aerogel to a second contact reaction for 1 to 2 hours to obtain a second polymer;

[0047] (3) At 30° C., stirring the second polymer and water at 600-800 rpm for 0.5-1 h, and then removing the solvent at 40° C. under vacuum (vacuum degree of 0.1-0.5 MPa) for 40 min to obtain a polyurethane waterproof coating.

[0048] Embodiment 3:

[0049] 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, 6 parts by weight of silica aerogel, and 110 parts by weight of water;

[0050] The preparation method of the polyurethane waterproof coating of this embodiment is as follows:

[0051] (1) contacting and mixing 1,4-butanediol and polyether triol Bluestar Dongda EP-3600 for 20 minutes at room temperature, heating to 90° C., adding dicyclohexylmethane diisocyanate and dibutyltin diacetate to the product obtained after the contacting and mixing to carry out a first contact reaction, reacting for 1 to 2 hours, and dehydrating for 1 to 2 hours at a vacuum degree of 0.1 to 0.5 MPa to obtain a first polymer;

[0052] (2) at 90° C., subjecting the first polymer, polyethylene glycol, epoxidized soybean oil, ethyl acetate, near-infrared reflective titanium dioxide, and silica aerogel to a second contact reaction for 1 to 2 hours to obtain a second polymer;

[0053] (3) At 30° C., stirring the second polymer and water at 600-800 rpm for 0.5-1 h, and then removing the solvent at 40° C. under vacuum (vacuum degree of 0.1-0.5 MPa) for 40 min to obtain a polyurethane waterproof coating.

[0054] Embodiment 4:

[0055] 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, 6 parts by weight of hollow glass microspheres, and 120 parts by weight of water;

[0056] The preparation method of the polyurethane waterproof coating of this embodiment is as follows:

[0057] (1) at room temperature, ethylene glycol and polyether triol Bluestar Dongda EP-330N are contacted and mixed for 20 minutes, the temperature is raised to 90° C., isophorone diisocyanate and stannous octoate are added to the product obtained after the contact and mixing to carry out a first contact reaction, the reaction is carried out for 1 to 2 hours, and a dehydration treatment is carried out at a vacuum degree of 0.1 to 0.5 MPa for 1 to 2 hours to obtain a first polymer;

[0058] (2) at 90° C., subjecting the first polymer, propylene glycol, tributyl phosphate, propylene glycol methyl ether acetate, near-infrared reflective titanium dioxide, and hollow glass microspheres to a second contact reaction for 1 to 2 hours to obtain a second polymer;

[0059] (3) At 30° C., stirring the second polymer and water at 600-800 rpm for 0.5-1 h, and then removing the solvent at 40° C. under vacuum (vacuum degree of 0.1-0.5 MPa) for 40 min to obtain a polyurethane waterproof coating.

[0060] Embodiment 5:

[0061] 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, 6 parts by weight of hollow glass microspheres, and 100 parts by weight of water;

[0062] The preparation method of the polyurethane waterproof coating of this embodiment is as follows:

[0063] (1) at room temperature, polyester diol, 1,4-butanediol and polyether triol Bluestar Dongda 10LD76E are contacted and mixed for 20 minutes, the temperature is raised to 90° C., 1,4-cyclohexane diisocyanate, cyclohexane dimethylene diisocyanate and triethylene diamine are added to the product obtained after the contact and mixing to carry out a first contact reaction, the reaction is carried out for 1 to 2 hours, and a dehydration treatment is carried out at a vacuum degree of 0.1 to 0.5 MPa for 1 to 2 hours to obtain a first polymer;

[0064] (2) subjecting the first polymer, polyethylene glycol, propylene glycol, dibutyl phthalate, ethyl acetate, near-infrared reflective titanium dioxide, and hollow glass microspheres to a second contact reaction at 90° C. for 1 to 2 hours to obtain a second polymer;

[0065] (3) At 30° C., stirring the second polymer and water at 600-800 rpm for 0.5-1 h, and then removing the solvent at 40° C. under vacuum (vacuum degree of 0.1-0.5 MPa) for 40 min to obtain a polyurethane waterproof coating.

[0066] Embodiment 6:

[0067] 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, 4 parts by weight of hollow glass microspheres, and 70 parts by weight of water;

[0068] The preparation method of the polyurethane waterproof coating of this embodiment is as follows:

[0069] (1) at room temperature, ethylene glycol and polyether triol Bluestar Dongda EP-330N are contacted and mixed for 20 minutes, the temperature is raised to 90° C., isophorone diisocyanate and stannous octoate are added to the product obtained after the contact and mixing to carry out a first contact reaction, the reaction is carried out for 1 to 2 hours, and a dehydration treatment is carried out at a vacuum degree of 0.1 to 0.5 MPa for 1 to 2 hours to obtain a first polymer;

[0070] (2) at 90° C., subjecting the first polymer, propylene glycol, tributyl phosphate, propylene glycol methyl ether acetate, near-infrared reflective titanium dioxide, and hollow glass microspheres to a second contact reaction for 1 to 2 hours to obtain a second polymer;

[0071] (3) At 30° C., stirring the second polymer and water at 600-800 rpm for 0.5-1 h, and then removing the solvent at 40° C. under vacuum (vacuum degree of 0.1-0.5 MPa) for 40 min to obtain a polyurethane waterproof coating.

[0072] Embodiment 7:

[0073] 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, 6 parts by weight of hollow glass microspheres, and 130 parts by weight of water;

[0074] The preparation method of the polyurethane waterproof coating of this embodiment is as follows:

[0075] (1) at room temperature, polyester diol, 1,4-butanediol and polyether triol Bluestar Dongda 10LD76E are contacted and mixed for 20 minutes, the temperature is raised to 80° C., 1,4-cyclohexane diisocyanate, cyclohexane dimethylene diisocyanate and triethylene diamine are added to the product obtained after the contact and mixing to carry out a first contact reaction, the reaction is carried out for 1 to 2 hours, and a dehydration treatment is carried out at a vacuum degree of 0.05 MPa for 1 to 2 hours to obtain a first polymer;

[0076] (2) subjecting the first polymer, polyethylene glycol, propylene glycol, dibutyl phthalate, ethyl acetate, near-infrared reflective titanium dioxide, and hollow glass microspheres to a second contact reaction at 80° C. for 1 to 2 hours to obtain a second polymer;

[0077] (3) At 20° C., the second polymer and water are stirred at 600-800 rpm for 0.5-1 h, and then the solvent is removed at 30° C. under vacuum (vacuum degree is 0.05 MPa) for 40 min to obtain a polyurethane waterproof coating.

[0078] Embodiment 8:

[0079] 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;

[0080] The preparation method of the polyurethane waterproof coating of this embodiment is as follows:

[0081] (1) contacting and mixing ethylene glycol and polyether triol Bluestar Dongda EP-330N for 20 minutes at room temperature, heating to 100° C., adding isophorone diisocyanate and stannous octoate to the product obtained after the contacting and mixing for a first contact reaction, reacting for 1 to 2 hours, and dehydrating for 1 to 2 hours at a vacuum degree of 0.6 MPa to obtain a first polymer;

[0082] (2) at 100° C., subjecting the first polymer, propylene glycol, tributyl phosphate, propylene glycol methyl ether acetate, near-infrared reflective titanium dioxide, and hollow glass microspheres to a second contact reaction for 1 to 2 hours to obtain a second polymer;

[0083] (3) At 40° C., stirring the second polymer and water at 600-800 rpm for 0.5-1 h, and then removing the solvent at 50° C. under vacuum (vacuum degree of 0.6 MPa) for 40 min to obtain a polyurethane waterproof coating.

[0084] Embodiment 9:

[0085] 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.

[0086] 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.

[0087] The tensile strength and elongation are tested according to the method specified in Chapter 9 of GB / T16777-2008;

[0088] 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;

[0089] The calculation formula of the self-repairing efficiency is: (tensile strength of the sample after self-repairing / initial tensile strength of the sample)×100%.

[0090] Table 1

[0091] Tensile strength, MPa Elongation, % Self-repair efficiency, % Example 1 8.7 725 96 Example 2 8.1 637 93 Example 3 7.6 586 91 Example 4 7.8 598 89 Example 5 7.5 575 92 Example 6 4.5 387 72 Example 7 4.7 362 68 Example 8 4.2 355 63

[0092] 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.

[0093] 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.

[0094] 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 method for preparing a polyurethane waterproof coating containing diisocyanate, characterized in that: The composition comprises the following components by weight: (1) subjecting 10-30 parts by weight of a diol, 10-60 parts by weight of a polyether triol, 7-15 parts by weight of a diisocyanate, and 0.05-1.0 parts by weight of a polymerization catalyst to a first contact reaction to obtain a first polymer; (2) subjecting the first polymer, 1.0-5.0 parts by weight of a chain extender, 15-30 parts by weight of a plasticizer, 10-30 parts by weight of a solvent, 2-5 parts by weight of near-infrared reflective titanium dioxide, and 5-15 parts by weight of a thermal insulation filler to a second contact reaction to obtain a second polymer; (3) The second polymer is subjected to an emulsification reaction with 80-120 parts by weight of water, and the product obtained after the emulsification reaction is subjected to a degassing treatment.

2. The method according to claim 1, wherein: In step (1), 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 method according to claim 1, wherein: In step (1), 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 method according to claim 1, wherein: In step (1), 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 method according to claim 1, wherein: In step (1), the polymerization catalyst is selected from one or more of dibutyltin dilaurate, stannous octoate, dibutyltin diacetate, triethylamine, and triethylenediamine.

6. The method according to claim 1, wherein: In step (2), the chain extender is selected from one or more of trimethylolpropane, ethylene glycol, propylene glycol, polyethylene glycol, and 1,4-butanediol.

7. The method according to claim 1, wherein: In step (2), 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 method according to claim 1, wherein: In step (2), 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.

9. The method according to claim 1, wherein: In step (1), the conditions of the first contact reaction include at least: a temperature of 85-95°C and a vacuum degree of 0.1-0.5 MPa; in step (2), the conditions of the second contact reaction include at least: a temperature of 85-95°C; in step (3), the reaction conditions include at least: an initial temperature of 25-35°C, a later temperature of 35-45°C, and a vacuum degree of 0.1-0.5 MPa.

10. A polyurethane waterproof coating containing diisocyanate prepared by the method described in any one of claims 1 to 9.