Heat-insulating and heat-preserving waterproof coating and preparation method thereof

Abstract

The invention belongs to the technical field of coatings. The invention relates to a waterproof coating, in particular to a heat-insulating and heat-preserving waterproof coating and a preparation method thereof. The coating product is prepared from the following raw materials in parts by weight: 100 to 120 parts of hydroxy acrylic resin, 40 to 50 parts of composite reflective filler, 1 to 2 parts of dispersing agent, 30 to 40 parts of solvent propylene glycol methyl ether acetate, 10 to 12 parts of curing agent N3390, 0.3 to 0.5 part of flatting agent and 0.2 to 0.4 part of defoaming agent. The composite reflective filler comprises an inner core and a shell covering the surface of the inner core, the inner core is rutile type nano titanium dioxide; the shell is composed of aluminum oxide and silicon dioxide; the D50 of the rutile type nano titanium dioxide ranges from 260 nm to 300 nm; the average thickness of the shell is 50 to 60 nm; and in the shell, the molar ratio of the aluminum element to the silicon element is 1: (8-9).

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of coatings. More particularly, it relates to a waterproof coating for thermal insulation and a preparation method thereof. BACKGROUND

[0002] Waterproof coating for thermal insulation is a multifunctional building material that combines waterproofing, thermal insulation, and heat preservation functions. It is widely used in building roofing, exterior walls, industrial buildings, and other fields. This type of coating typically has the ability to reflect sunlight, reduce building surface temperature, and reduce heat transfer, while also effectively preventing moisture penetration.

[0003] For example, commonly used acrylic reflective coatings use acrylic resin as the base material, and reflective fillers such as titanium dioxide (TiO2), zinc oxide (ZnO), and hollow glass microbeads to improve solar reflectance (typically ≥80%). Although reflective coatings perform well in the short term, long-term exposure to outdoor environments (UV, high temperature, rain, pollution, etc.) can lead to performance degradation, with the main failure mechanisms being:

[0004] Degradation of the coating caused by UV aging: UV radiation (especially in the 280-400 nm band) can damage the molecular chain of the resin, leading to powdering, brittleness, and loss of elasticity on the surface of the coating. Titanium dioxide may undergo a photocatalytic reaction under UV irradiation, accelerating the oxidation of the resin (especially rutile titanium dioxide, which is relatively stable but still has some catalytic activity);

[0005] Coating cracking / peeling caused by thermal stress: diurnal temperature differences or seasonal temperature changes (such as -30℃-80℃) cause the coating to repeatedly expand / contract, and if the elasticity is insufficient (such as ordinary acrylic coatings with an elongation at break <150%), microcracks are easily produced.

[0006] Therefore, how to improve the weather resistance of waterproof coatings for thermal insulation and extend their service life remains one of the technical challenges faced by those skilled in the art. SUMMARY

[0007] The technical problem to be solved by the present application is to provide a waterproof coating for thermal insulation and a preparation method thereof, which addresses the problem of limited service life due to insufficient weather resistance of existing waterproof coatings for thermal insulation.

[0008] The purpose of the present application is to provide a waterproof coating for thermal insulation.

[0009] Another purpose of the present application is to provide a preparation method for a waterproof coating for thermal insulation.

[0010] The above-mentioned purposes of the present application are achieved by the following technical solutions:

[0011] A kind of heat insulation waterproof coating, comprising the following raw materials by weight fraction:

[0012] 100-120 parts of hydroxyl acrylic resin, 40-50 parts of composite reflective filler, 1-2 parts of dispersing agent, 30-40 parts of solvent propylene glycol methyl ether acetate, curing agent N3390 10-12 parts, leveling agent 0.3-0.5 parts, defoaming agent 0.2-0.4 parts;

[0013] The composite reflective filler includes a core and a shell coated on the surface of the core.

[0014] The core is rutile nano titanium dioxide, and the shell is composed of alumina and silica.

[0015] The above technical solution has the following advantages:

[0016] The above technical solution uses rutile nano titanium dioxide as the core and alumina and silica to form a composite shell. Rutile nano titanium dioxide has strong reflection ability for visible light, and the shell composed of alumina and silica can enhance the scattering and interference reflection of near-infrared light (700-2500 nm) by adjusting the refractive index gradient (silica is 1.45 and alumina is 1.76). As a result, the solar reflectance (TSR) of the coating reaches more than 0.90, exceeding the basic level of 0.8 required by the national standard GB / T25261. Specifically, because alumina is white and silica is transparent, there is a difference in their optical properties. Alumina has a higher refractive index than silica, so it can increase the Fresnel reflection at the interface, especially in the ultraviolet-visible light band. In addition, alumina particles act as secondary scattering centers, enhancing Mie scattering, especially for near-infrared light.

[0017] More importantly, during the long-term use of the product, the shell coating layer can physically isolate UV light from the titanium dioxide core, reducing the generation of electron-hole pairs and significantly reducing the degradation rate of the coating due to photocatalysis.

[0018] However, the inventors found that a single silica coating layer is prone to forming pores during the coating process, which can compromise the shielding effect of the nano titanium dioxide. The presence of alumina can fill the micropores formed during the silica sol-gel process, making the coating layer more continuous and significantly reducing the number of pore defects.

[0019] Further, the D50 of the rutile nano titanium dioxide is 260-300 nm, and the average thickness of the shell is 50-60 nm.

[0020] The above technical solution has the following advantages:

[0021] By further regulating the average thickness of the shell and the particle size of the core, the reflectivity of the core and the shell to near-infrared light is further improved; specifically, the thickness of the shell can be regulated by regulating the amount of precursor when prepared by the following preparation method, or by regulating the time of the gel formation process.

[0022] Further, the sphericity of the rutile type nano-titanium dioxide is 0.8-0.9.

[0023] Further, in the shell, the molar ratio of aluminum element to silicon element is 1:8-9.

[0024] The beneficial effects of the above technical solutions are:

[0025] By regulating the molar ratio of aluminum element to silicon element, the proportion of aluminum oxide and silicon dioxide in the shell coating layer is regulated, which avoids the decrease of light transmittance caused by too high content of aluminum oxide, and the hardness of aluminum oxide is higher. If the amount of addition is too much, it will cause the shell to fall off with the change of temperature during mixing or use, thereby weakening the shielding effect of titanium dioxide after coating. Therefore, it is necessary to control it within the above reasonable range.

[0026] Further, the dispersant is polyurethane type BYK-163 dispersant; the leveling agent is silicone type BYK-331 leveling agent; and the defoaming agent is BYK-066N defoaming agent.

[0027] A preparation method of a heat-insulating waterproof coating, and the specific preparation steps include:

[0028] Preparation of the composite reflective filler:

[0029] Ethyl orthosilicate and aluminum isopropyl alcohol are used as precursors;

[0030] Ethyl orthosilicate and aluminum isopropyl alcohol are mixed and poured into anhydrous ethanol, wherein the concentration of the precursors is 0.8-1.0 mol / L;

[0031] Then, deionized water is slowly added, and the pH is adjusted to 9.0-10.0 with ammonia water, and then the mixed sol is obtained by stirring at a temperature of 40-42℃ and a stirring speed of 180-220r / min for 4-5h.

[0032] Wherein, the molar ratio of deionized water to precursor is 4:1;

[0033] The rutile type nano-titanium dioxide is dispersed in anhydrous ethanol at a solid-liquid mass ratio of 1:10 to obtain a titanium dioxide dispersion;

[0034] Then the mixed sol is added drop by drop into the titanium dioxide dispersion liquid, and after the addition is completed, heating and stirring are continued at a temperature of 40-45℃ and a stirring speed of 260-300r / min for 4-6h, and then heating is continued to 60-65℃, and aging is continued for 3-4h;

[0035] Centrifugal separation, drying, and then aging and calcining at a temperature of 480-500℃ for 2-3h, cooling, and discharging, to obtain the composite reflective filler;

[0036] Prepare each component according to the composition of the raw materials;

[0037] Divide the solvent propylene glycol methyl ether acetate into two parts;

[0038] Mix one part of the solvent with the composite reflective filler, and then add a dispersant, and then mix at a speed of 1000-1200r / min for 30-40min to obtain a composite reflective filler dispersion liquid;

[0039] Mix the other part of the solvent with the hydroxy acrylate resin at a stirring speed of 300r / min, and then add a leveling agent and a defoaming agent, and continue to mix for 30-40min to obtain a resin diluent;

[0040] Add the composite reflective filler dispersion liquid to the resin diluent, and mix at a stirring speed of 500-600r / min for 60-80min, then add a curing agent, continue to stir for 10min, and then stand for 30-45min to obtain a heat-insulating and waterproof coating.

[0041] Further, the slow addition of deionized water is to add deionized water at a rate of 6-8mL / min;

[0042] The dropwise addition of the mixed sol is to add the mixed sol at a rate of 4-6g / min.

[0043] Further, in the precursor, the molar ratio of aluminum element to silicon element in the tetraethyl orthosilicate and the aluminum isopropoxide is 1:8-9.

[0044] Further, the specific preparation steps further include:

[0045] Mix the tetraethyl orthosilicate and the aluminum isopropoxide into anhydrous ethanol, wherein the concentration of the precursor is 0.8-1.0mol / L;

[0046] Then, isopropyl alcohol aluminum is added in an equimolar amount of acetylacetone, after being mixed uniformly, deionized water is slowly added dropwise, after the dropwise addition is completed, the pH is adjusted to 9.0-10.0 with ammonia water, then under the condition that the temperature is 40-42℃ and the stirring speed is 180-220r / min, the stirring reaction is carried out for 4-5h, and a mixed sol is obtained. DETAILED DESCRIPTION

[0047] The application will be further described below in conjunction with specific examples, but the examples do not limit the application in any form. Unless otherwise specified, the reagents, methods and equipment used in the application are conventional reagents, methods and equipment in the technical field.

[0048] Unless otherwise specified, the reagents and materials used in the following examples are commercially available.

[0049] Example 1

[0050] Preparation of the composite reflective filler:

[0051] Ethyl orthosilicate and isopropyl alcohol aluminum are used as precursors; in the precursors, the ethyl orthosilicate and the isopropyl alcohol aluminum are dosed according to a molar ratio of aluminum element to silicon element of 1:8;

[0052] The ethyl orthosilicate and the isopropyl alcohol aluminum are mixed and poured into anhydrous ethanol, and dosed according to a total concentration of the precursors in the anhydrous ethanol of 0.8mol / L; then, isopropyl alcohol aluminum is added in an equimolar amount of acetylacetone, after the addition is completed, a continuous stirring is carried out at a stirring speed of 200r / min for 20min, and an aluminum source and silicon source precursor solution is obtained;

[0053] Then, deionized water is slowly added dropwise to the obtained aluminum source and silicon source precursor solution at a rate of 6mL / min, after the dropwise addition is completed, the pH is adjusted to 9.0 with ammonia water, then under the condition that the temperature is 40℃ and the stirring speed is 180r / min, the stirring reaction is carried out for 4h, and a mixed sol is obtained;

[0054] The molar ratio of the deionized water to the precursors is 4:1;

[0055] Rutile type nano titanium dioxide is added into anhydrous ethanol according to a solid-liquid mass ratio of 1:10, and is ultrasonically dispersed for 30min under the condition that the ultrasonic frequency is 70kHz, and a titanium dioxide dispersion liquid is obtained;

[0056] The D50 of the rutile type nano titanium dioxide is 260nm; and the sphericity of the rutile type nano titanium dioxide is 0.8;

[0057] Then the mixed sol was added dropwise into the titanium dioxide dispersion liquid at a rate of 4 g / min, after the addition was completed, the heating and stirring reaction was continued at a temperature of 40℃ and a stirring speed of 260 r / min for 4 h, then the temperature was increased to 60℃ and the aging was continued for 3 h;

[0058] After the aging was completed, centrifugal separation was performed, the filter cake was collected and washed with anhydrous ethanol for 3 times, then the washed filter cake was dried to a constant weight at a temperature of 100℃, and then calcined at a temperature of 480℃ for 2 h, the furnace was cooled to room temperature, and the product was discharged, thereby obtaining the composite reflective filler;

[0059] By controlling the above process conditions, the average thickness of the shell was regulated to be 50 nm, which was specifically measured by TEM on 10 particles at random, and then the average value was obtained;

[0060] According to the weight parts, 100 parts of hydroxyl acrylic resin, 40 parts of composite reflective filler, 1 part of dispersant, 30 parts of solvent propylene glycol methyl ether acetate, 10 parts of curing agent N3390, 0.3 parts of leveling agent, and 0.2 parts of defoaming agent were taken;

[0061] The solid content of the hydroxyl acrylic resin is 50%, the dispersant is polyurethane type BYK-163 dispersant, the leveling agent is silicone type BYK-331 leveling agent, and the defoaming agent is BYK-066N defoaming agent;

[0062] The solvent propylene glycol methyl ether acetate was divided into two equal parts;

[0063] One part of the solvent was mixed with the composite reflective filler and the dispersant was added, then high-speed stirring was performed at a speed of 1000 r / min for 30 min, thereby obtaining a composite reflective filler dispersion liquid;

[0064] The other part of the solvent was mixed with the hydroxyl acrylic resin at a stirring speed of 300 r / min, and then the leveling agent and the defoaming agent were added, and the stirring and mixing were continued for 30 min, thereby obtaining a resin diluent;

[0065] The composite reflective filler dispersion liquid was added to the resin diluent, and stirring and mixing were performed at a stirring speed of 500 r / min for 60 min, then the curing agent was added, and the stirring was continued for 10 min, and then the product was left to stand for 30 min, thereby obtaining the heat-insulating and waterproof coating.

[0066] Example 2

[0067] Preparation of the composite reflective filler:

[0068] Ethyl orthosilicate and aluminum isopropoxide are used as precursors; in the precursors, the ethyl orthosilicate and the aluminum isopropoxide are proportioned according to a molar ratio of aluminum element to silicon element of 1:8.5;

[0069] The ethyl orthosilicate and the aluminum isopropoxide are mixed and poured into anhydrous ethanol, and are proportioned according to a total concentration of the precursors in the anhydrous ethanol of 0.9 mol / L; then, acetylacetone in an equimolar amount of the aluminum isopropoxide is added, and after the addition is completed, a stirrer is continuously stirred at a rotating speed of 200 r / min for 20 min to obtain an aluminum source and a silicon source precursor solution;

[0070] Further, deionized water is slowly added dropwise to the obtained aluminum source and silicon source precursor solution at a rate of 7 mL / min, and after the dropwise addition is completed, the pH is adjusted to 9.5 with ammonia water; then, under the condition that the temperature is 41℃ and the stirring rotating speed is 200 r / min, the stirring reaction is performed for 4.5 h to obtain a mixed sol;

[0071] In the formula, the molar ratio of the deionized water to the precursors is 4:1;

[0072] Rutile nano-titanium dioxide is added into anhydrous ethanol according to a solid-liquid mass ratio of 1:10, and is ultrasonically dispersed for 35 min under the condition that the ultrasonic frequency is 75 kHz to obtain a titanium dioxide dispersion liquid;

[0073] The D50 of the rutile nano-titanium dioxide is 280 nm; and the sphericity of the rutile nano-titanium dioxide is 0.85;

[0074] Further, the mixed sol is added dropwise to the titanium dioxide dispersion liquid at a rate of 5 g / min, and after the dropwise addition is completed, the heating and stirring reaction is continuously performed under the condition that the temperature is 42℃ and the stirring rotating speed is 280 r / min for 5 h, and then the heating temperature is increased to 62℃, and the aging is performed for 3.4 h;

[0075] After the aging is completed, centrifugal separation is performed, the filter cake is collected, and the filter cake is washed with anhydrous ethanol for 3 times; then, the washed filter cake is dried at a temperature of 100℃ until the weight is constant, and then the filter cake is calcined at a temperature of 490℃ for 2.3 h, and then the filter cake is cooled to room temperature in the furnace, and the product is discharged to obtain a composite reflective filler;

[0076] Through the control of the above process conditions, the average thickness of the shell is regulated to be 55 nm, and the average thickness is specifically measured by randomly selecting 10 particles by TEM, and then the average value is obtained;

[0077] According to weight parts, 110 parts of hydroxy acrylic resin, 45 parts of composite reflective filler, 1.2 parts of dispersant, 35 parts of solvent propylene glycol methyl ether acetate, 11 parts of curing agent N3390, 0.4 parts of leveling agent, and 0.3 parts of defoaming agent are taken;

[0078] The solid content of the hydroxyl acrylic resin is 50%, the dispersant is polyurethane type BYK-163 dispersant; the leveling agent is silicone type BYK-331 leveling agent; and the defoaming agent is BYK-066N defoaming agent.

[0079] The solvent propylene glycol methyl ether acetate is divided into two parts;

[0080] One part of the solvent is mixed with the composite reflective filler, and a dispersant is added, and then the mixture is stirred at a speed of 1100 r / min for 35 min to obtain a composite reflective filler dispersion liquid;

[0081] The other part of the solvent is mixed with the hydroxyl acrylic resin, and a leveling agent and a defoaming agent are added, and then the mixture is stirred at a speed of 300 r / min for 35 min to obtain a resin diluent;

[0082] The composite reflective filler dispersion liquid is added to the resin diluent, and the mixture is stirred at a speed of 550 r / min for 70 min, and then a curing agent is added, and the mixture is stirred for 10 min, and then it is left to stand for 35 min to obtain a waterproof thermal insulation coating.

[0083] Example 3

[0084] Preparation of the composite reflective filler:

[0085] Tetraethyl orthosilicate and aluminum isopropoxide are used as precursors; in the precursors, the tetraethyl orthosilicate and the aluminum isopropoxide are dosed according to a molar ratio of aluminum element to silicon element of 1:9;

[0086] The tetraethyl orthosilicate and the aluminum isopropoxide are mixed and poured into anhydrous ethanol, and the total concentration of the precursors in the anhydrous ethanol is 1.0 mol / L; then acetylacetone in an amount equal to that of the aluminum isopropoxide is added, and after the addition is completed, a stirrer is used to continuously stir at a speed of 200 r / min for 20 min to obtain an aluminum source and silicon source precursor solution;

[0087] Then, deionized water is slowly added to the obtained aluminum source and silicon source precursor solution at a rate of 8 mL / min, and after the addition is completed, the pH is adjusted to 10.0 with ammonia water, and then the mixture is stirred at a temperature of 42℃ and a stirring speed of 220 r / min for 5 h to obtain a mixed sol;

[0088] The molar ratio of the deionized water to the precursors is 4:1;

[0089] Rutile type nano titanium dioxide is added to anhydrous ethanol at a solid-liquid mass ratio of 1:10, and ultrasonic dispersion is performed at an ultrasonic frequency of 80 kHz for 40 min to obtain a titanium dioxide dispersion liquid;

[0090] The D50 of the rutile-type nano-titanium dioxide is 300 nm; and the sphericity of the rutile-type nano-titanium dioxide is 0.9.

[0091] Subsequently, the mixed sol is added dropwise into the titanium dioxide dispersion liquid at a rate of 6 g / min, and after the addition is completed, heating and stirring are continued at a temperature of 45℃ and a stirring speed of 300 r / min for 6 h, and then the temperature is increased to 65℃, and the aging is continued for 4 h;

[0092] After the aging is completed, centrifugal separation is performed, the filter cake is collected, and the filter cake is washed with anhydrous ethanol for 3 times, and then the washed filter cake is dried at a temperature of 100℃ until the weight is constant, and then the filter cake is calcined at a temperature of 500℃ for 3 h, and then the temperature is cooled to room temperature, and the product is discharged, thereby obtaining the composite reflective filler.

[0093] Through the control of the above process conditions, the average thickness of the shell is controlled to be 60 nm, and the average thickness is specifically measured by randomly taking 10 particles by TEM, and then the average value is obtained.

[0094] According to the weight parts, 120 parts of hydroxyl acrylic resin, 50 parts of composite reflective filler, 2 parts of dispersant, 40 parts of solvent propylene glycol methyl ether acetate, 12 parts of curing agent N3390, 0.5 parts of leveling agent, and 0.4 parts of defoaming agent are taken.

[0095] The solid content of the hydroxyl acrylic resin is 50%, the dispersant is polyurethane type BYK-163 dispersant, the leveling agent is silicone type BYK-331 leveling agent, and the defoaming agent is BYK-066N defoaming agent.

[0096] The solvent propylene glycol methyl ether acetate is divided into two parts;

[0097] One part of the solvent is mixed with the composite reflective filler, and the dispersant is added, and then high-speed stirring is performed at a speed of 1200 r / min for 40 min, thereby obtaining a composite reflective filler dispersion liquid.

[0098] The other part of the solvent is mixed with the hydroxyl acrylic resin at a stirring speed of 300 r / min, and then the leveling agent and the defoaming agent are added, and stirring is continued for 40 min, thereby obtaining a resin diluent.

[0099] The composite reflective filler dispersion liquid is added to the resin diluent, and stirring is performed at a stirring speed of 600 r / min for 80 min, and then the curing agent is added, and stirring is continued for 10 min, and then the product is left to stand for 45 min, thereby obtaining a heat-insulating and waterproof coating.

[0100] Example 4

[0101] The difference between this example and Example 1 is that the molar ratio of aluminum element to silicon element is 1:7, and the rest of the conditions remain unchanged.

[0102] Example 5

[0103] The difference between this example and Example 1 is that the molar ratio of aluminum element to silicon element is 1:10, and the rest of the conditions remain unchanged.

[0104] Comparative Example 1

[0105] The difference between this comparative example and Example 1 is that no aluminum isopropoxide is added, and the rest of the conditions remain unchanged.

[0106] Comparative Example 2

[0107] The difference between this comparative example and Example 1 is that no tetraethyl orthosilicate and aluminum isopropoxide are added, and it can be understood that the nano-titanium dioxide surface is not coated and is directly used in the paint.

[0108] The products obtained in the above examples and comparative examples are subjected to performance testing, and the specific testing methods and testing results are as follows:

[0109] Preparation of samples:

[0110] A circular anodized aluminum plate with a diameter of 25 mm is used as a substrate, and the substrate is wiped with acetone or ethanol to remove grease and dust, and then dried in an 80°C oven for 30 minutes to ensure no water remains; a doctor blade is used to control the gap to 100 pm, and after coating is completed, it is baked and cured at a temperature of 80°C for 1 h, and then placed at room temperature for 7 d, and then tested;

[0111] Solar reflectance test: according to standard ASTM E903, the spectral range is 300-2500 nm, the incident angle is 8°, and the reflectivity 1 is obtained by testing, and the specific test results are shown in Table 1;

[0112] After the paint is subjected to a simulated aging test, the corresponding reflectivity 2 is obtained according to the above standard, and the specific test results are shown in Table 1;

[0113] Specifically, the simulated aging test is carried out according to the following method:

[0114] First, in a constant temperature and humidity chamber, after continuous exposure at a temperature of 40°C and a humidity of 95% for 28 d, it is transferred to a high-low temperature alternating test chamber, placed at -30°C for 2 h, then placed at room temperature for 1 h, and then placed at 80°C for 2 h, and then placed at room temperature for 1 h, which is considered as one cycle, and the high-low temperature cycle is repeated 100 times.

[0115] Table 1: Product performance test results

[0116] Reflectance 1 Reflectance 2 Example 1 0.932 0.899 Example 2 0.935 0.903 Example 3 0.936 0.904 Example 4 0.911 0.870 Example 5 0.938 0.875 Comparative Example 1 0.939 0.862 Comparative Example 2 0.922 0.845

[0117] From the test results of Table 1, it can be seen that the coating product obtained by the technical scheme of the present application not only has excellent initial light reflection effect, but also can still have excellent reflectivity after aging resistance test.

[0118] The above examples are the preferred embodiments of the present application, but the embodiments of the present application are not limited by the above examples, and any changes, modifications, substitutions, combinations, simplifications made without departing from the spirit and principles of the present application should be equivalent replacement methods, and are all included in the protection scope of the present application.

Claims

1. A heat-insulating waterproof coating, characterized in that: The composition comprises the following raw materials in parts by weight: 100-120 parts of hydroxy acrylic resin, 40-50 parts of composite reflective filler, 1-2 parts of dispersant, 30-40 parts of solvent propylene glycol methyl ether acetate, 10-12 parts of curing agent N3390, 0.3-0.5 parts of leveling agent, 0.2-0.4 parts of defoaming agent; The composite reflective filler comprises a core and a shell covering the surface of the core; The core is rutile nano-titanium dioxide; the shell is composed of aluminum oxide and silicon dioxide.

2. A heat-insulating waterproof coating according to claim 1, characterized in that: The D50 of the rutile nano-titanium dioxide is 260-300 nm; and the average thickness of the shell is 50-60 nm.

3. The heat-insulating waterproof coating according to claim 2, characterized in that: The sphericity of the rutile nano-titanium dioxide is 0.8-0.

9.

4. The heat-insulating waterproof coating according to claim 1, characterized in that: In the shell, the molar ratio of aluminum element to silicon element is 1:8-9.

5. The heat-insulating waterproof coating according to claim 1, characterized in that: The dispersant is a polyurethane BYK-163 dispersant; the leveling agent is a silicone BYK-331 leveling agent; and the defoaming agent is a BYK-066N defoaming agent.

6. A method for preparing a heat-insulating waterproof coating according to any one of claims 1 to 5, characterized in that: The specific preparation steps include: Preparation of composite reflective filler: Using tetraethyl orthosilicate and aluminum isopropoxide as precursors; Mix ethyl orthosilicate and aluminum isopropoxide and pour them into anhydrous ethanol, wherein the concentration of the precursor is 0.8-1.0 mol / L; Then, deionized water is slowly added dropwise. After the addition is complete, the pH is adjusted to 9.0-10.0 with aqueous ammonia. The mixture is then stirred at a temperature of 40-42°C and a stirring speed of 180-220 r / min for 4-5 hours to obtain a mixed sol. The molar ratio of deionized water to precursor is 4:1; Dispersing rutile nano-titanium dioxide in anhydrous ethanol at a solid-liquid mass ratio of 1:10 to obtain a titanium dioxide dispersion; Then, the mixed sol is added dropwise to the titanium dioxide dispersion. After the addition is completed, the mixture is heated and stirred at a temperature of 40-45°C and a stirring speed of 260-300 r / min for 4-6 hours, and then heated to 60-65°C and aged for 3-4 hours; Centrifugal separation, drying, and then calcining at a temperature of 480-500°C for 2-3 hours, cooling, and discharging to obtain a composite reflective filler; Prepare each component according to the raw material composition; The solvent propylene glycol methyl ether acetate was divided into two equal parts; Mix one portion of the solvent with the composite reflective filler, add a dispersant, and then stir at a high speed of 1000-1200 r / min for 30-40 minutes to obtain a composite reflective filler dispersion; Under the condition of stirring speed of 300r / min, another portion of solvent is mixed with hydroxy acrylic resin, and then leveling agent and defoaming agent are added, and stirring and mixing is continued for 30-40 minutes to obtain resin dilution; Add the composite reflective filler dispersion into the resin diluent, stir and mix for 60-80 minutes at a stirring speed of 500-600 r / min, then add the curing agent, continue stirring for 10 minutes, and let it stand and mature for 30-45 minutes to obtain the heat-insulating waterproof coating.

7. The method for preparing a heat-insulating waterproof coating according to claim 6, characterized in that: The slowly adding deionized water is as follows: adding deionized water at a rate of 6-8 mL / min; The step of adding the mixed sol dropwise is as follows: adding the mixed sol dropwise at a rate of 4-6 g / min.

8. The method for preparing a heat-insulating waterproof coating according to claim 6, characterized in that: In the precursor, the tetraethyl orthosilicate and the aluminum isopropoxide are mixed according to a molar ratio of aluminum element to silicon element of 1:8-9.

9. The method for preparing a heat-insulating waterproof coating according to claim 8, characterized in that: The specific preparation steps also include: Mix ethyl orthosilicate and aluminum isopropoxide and pour them into anhydrous ethanol, wherein the concentration of the precursor is 0.8-1.0 mol / L; Then, add acetylacetone in an amount equal to that of aluminum isopropoxide, and after mixing evenly, slowly add deionized water dropwise. After the addition is complete, adjust the pH to 9.0-10.0 with ammonia water, and then stir the reaction at a temperature of 40-42°C and a stirring speed of 180-220 r / min for 4-5 hours to obtain a mixed sol.