Mesoporous thermal insulation coating with infrared heat shielding function and preparation method thereof

Abstract

The invention relates to the technical field of coatings, in particular to a mesoporous thermal insulation coating with an infrared heat shielding function and a preparation method thereof. A polyurethane-organic silicon emulsion is selected as a base material of the coating, and a hydroxyl-terminated ternary flame retardant chain extender is used to extend a polyurethane prepolymer to prepare a highly flame-retardant and self-repairing polyurethane-organic silicon emulsion; hollow silica microspheres are selected as mesoporous materials, and are prepared by a two-step method of first hydrolyzing and condensing phenyltrimethoxysilane and then calcining to remove impurities; the hollow silica microspheres are modified to prepare composite hollow silica microspheres as fillers, and cesium-doped tungsten bronze nanoparticles are in situ grown on the surface of the hollow silica microspheres by a solvent thermal method to obtain pretreated hollow silica microspheres, which are treated with an epoxy silane coupling agent to obtain epoxidized hollow silica, and then the hydroxyl-terminated ternary flame retardant chain extender is grafted by an epoxy-hydroxyl reaction.

Description

Technical Field

[0001] The invention relates to the technical field of coatings, in particular to a mesoporous thermal insulation coating with infrared heat shielding function and a preparation method thereof. Background Art

[0002] At present, energy conservation and consumption reduction are important tasks for industrial enterprises, so it is very important to take thermal insulation measures for various equipment and pipelines. Existing enterprises mostly use wrapping insulation for insulation. In practical applications, most of them have problems such as high thermal conductivity, easy moisture absorption, complex process, and poor thermal insulation effect. Compared with wrapping thermal insulation materials, thermal insulation coatings with lower thermal conductivity, simple production process, significant thermal insulation effect and relatively simple construction are increasing their share in the thermal insulation market.

[0003] There are many types of thermal insulation coatings on the market, but most of them have problems such as easy falling off in high temperature environments, requiring thick coatings to achieve good thermal insulation effects, and single functions, which greatly limits the scope of use of thermal insulation coatings. Summary of the invention

[0004] The object of the present invention is to provide a mesoporous thermal insulation coating with infrared heat shielding function and a preparation method thereof, so as to solve the problems in the prior art.

[0005] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0006] A method for preparing a mesoporous thermal insulation coating having an infrared heat shielding function comprises the following steps:

[0007] S1: mixing an emulsified aqueous solution, a surfactant, γ-aminopropyltriethoxysilane, a fluorine monomer, and isobutyltriethoxysilane to obtain a solution A;

[0008] S2: Mix the polyurethane prepolymer and solution A, heat to 70-75°C and keep warm for 6-8 hours, add the chain extender, keep warm for 2-4 hours, add the emulsified aqueous solution and stir for 2-3 hours, adjust the pH to 7-8, and obtain a polyurethane-organic silicone emulsion;

[0009] S3: mixing the mesoporous material, the dispersant, anhydrous ethanol and deionized water to obtain a mesoporous slurry;

[0010] S4: hollow glass microspheres, ethanol, and deionized water are mixed, ultrasonically dispersed, mesoporous slurry, filler, calcium carbonate, and dispersant are added, ground, polyurethane-silicone emulsion is added, and then additives are added and stirred to obtain a mesoporous thermal insulation coating with infrared heat shielding function.

[0011] Furthermore, the emulsified aqueous solution is prepared by compounding an emulsifier and deionized water in a mass ratio of 1:15; in terms of mass fractions, the raw material composition of solution A is: 10-15 parts of emulsified aqueous solution, 1-3 parts of surfactant, 2-4 parts of γ-aminopropyltriethoxysilane, 1-2 parts of fluorine monomer, and 2-4 parts of isobutyltriethoxysilane.

[0012] Furthermore, the raw material composition of the polyurethane-silicone emulsion is, by weight: 12-17 parts of polyurethane prepolymer, 5-10 parts of solution A, 4-8 parts of chain extender, and 20-25 parts of emulsified aqueous solution.

[0013] Furthermore, the preparation of the polyurethane prepolymer includes the following steps: mixing polytetrahydrofuran, castor oil, and 4,4'-methylene diphenyl diisocyanate, adding polyester diol and dihydroxymethyl propionic acid, heating to 65-70°C and keeping the temperature for 8-10 hours to obtain the polyurethane prepolymer.

[0014] Furthermore, the raw material composition of the mesoporous slurry is, by weight: 5-10 parts of mesoporous material, 1-3 parts of dispersant, 10-18 parts of anhydrous ethanol, and 15-27 parts of deionized water.

[0015] Furthermore, the raw material composition of the thermal insulation coating is: 1-5 parts of hollow glass microspheres, 10-15 parts of ethanol, 20-30 parts of deionized water, 1-5 parts of mesoporous slurry, 2-10 parts of filler, 1-6 parts of calcium carbonate, 1-5 parts of dispersant, 18-24 parts of polyurethane-silicone emulsion, and 3-7 parts of additives.

[0016] Furthermore, the auxiliary agent is one or a combination of film-forming auxiliary agent, defoaming agent, anti-settling agent, leveling agent, wetting agent and pH regulator.

[0017] Furthermore, the mesoporous material is hollow silica microspheres, and the preparation includes the following steps:

[0018] Mix nitric acid and phenyltrimethoxysilane, heat to 58-62°C and keep in a water bath for 3-5 minutes, add ammonia water, stir for 1-2 hours, centrifuge, wash, dry, heat to 200°C and keep for 2 hours, then heat to 660°C and calcine for 16 hours to obtain hollow silica microspheres.

[0019] Furthermore, the chain extender is a hydroxyl-terminated ternary flame retardant chain extender, and the preparation thereof comprises the following steps:

[0020] (1) Mixing monoethanolamine borate and anhydrous ethanol, adding 2,4-dihydroxybenzaldehyde, keeping warm at 18-25°C for 10-12 hours, filtering under reduced pressure, washing, and drying to obtain a boron-containing Schiff base compound;

[0021] (2) Mixing the boron-containing Schiff base compound and N,N-dimethylformamide, heating to 63-66°C and keeping warm for 20-30 minutes, adding DOPO, and keeping warm for 10-12 hours, rotary evaporation, washing, and recrystallization to obtain a Schiff base compound containing NPB;

[0022] (3) Mixing a Schiff base compound containing NPB and diethanolamine, keeping the mixture at 38-42°C for 1-2 hours, washing and recrystallizing, and obtaining an intermediate preparation; in a nitrogen atmosphere, mixing the intermediate preparation, 4,4'-methylenediphenyl diisocyanate, and N,N-dimethylformamide, keeping the mixture at 58-62°C for 2-3 hours, washing and recrystallizing, and obtaining a hydroxyl-terminated ternary flame retardant chain extender.

[0023] Furthermore, the filler is a composite hollow silica microsphere, and the preparation includes the following steps:

[0024] 1) Mix the hollow silica microspheres and anhydrous ethanol, perform ultrasonic dispersion for 1-2 hours, add tungstate sol, cesium carbonate solution and citric acid solution, transfer to a reaction kettle, keep at 190-200°C for 70-72 hours, wash with water, wash with alcohol, centrifuge and dry to obtain pretreated hollow silica microspheres;

[0025] 2) 3-glyceropropyltrimethoxysilane, ethanol and deionized water were mixed, and the pretreated hollow silica microspheres were added, and ultrasonic stirring was performed for 1-2 hours, and the pH value of the solution was adjusted to 4, and stirred for 22-24 hours, and centrifuged, washed and dried to obtain epoxidized hollow silica microspheres;

[0026] 3) Mix the hydroxyl-terminated ternary flame retardant chain extender, epoxidized hollow silica microspheres, chloroform, and Amberlyst-15 ion exchange resin, stir ultrasonically for 1-2 hours, heat to 55-65° C. and keep warm for 2-3 hours, filter, and rotary evaporate to obtain composite hollow silica microspheres.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] The present invention provides a mesoporous thermal insulation coating with infrared heat shielding function and a preparation method thereof. The components thereof are optimized and designed. The coating formed after the prepared thermal insulation coating is cured is a multifunctional coating with low thermal conductivity, strong infrared shielding, high flame retardancy and self-repairing properties.

[0029] In order to improve the corrosion resistance of the thermal insulation coating, the present invention selects polyurethane-organic silicon emulsion as the base material of the coating, and in order to make the coating formed by the thermal insulation coating have excellent mechanical damage resistance and flame retardancy and fire resistance, to solve the problems that the coating is easily damaged during long-term use and produces microcracks, and exposure to media such as air and moisture will accelerate the diffusion of microcracks, so that the protective performance of the coating is significantly reduced. In the present invention, a hydroxyl-terminated ternary flame retardant chain extender is used to extend the polyurethane prepolymer to prepare a highly flame retardant and self-repairing polyurethane-organic silicon emulsion, wherein the hydroxyl-terminated ternary flame retardant chain extender is made of monoethanolamine borate and 2,4-dihydroxybenzaldehyde as raw materials to obtain a boron-containing Schiff base The compound is then further reacted with DOPO to generate a Schiff base compound containing NPB, thereby greatly improving the flame retardancy and smoke suppression of the coating; then, diethanolamine and a Schiff base compound containing NPB are used as raw materials to prepare a nitrogen-boron-coordinated compound with multiple dynamic bonds at one end of an amino group and a hydroxyl group at the other end as an intermediate preparation, wherein the generated borate ester bond and multiple dynamic bonds such as Schiff base construct a complex self-healing network, thereby improving the self-healing ability of the coating; the intermediate preparation is reacted with 4,4'-methylene diphenyl diisocyanate to prepare a hydroxyl-terminated compound with multiple dynamic bonds and containing N, P, and B ternary synergistic flame retardant, namely a hydroxyl-terminated ternary flame retardant chain extender.

[0030] In order to give the coating excellent thermal insulation, hollow silica microspheres are selected as mesoporous materials in the present invention. They are prepared by a two-step method of first hydrolyzing and condensing phenyltrimethoxysilane and then calcining to remove impurities. Compared with the common double template method, the simplified process and template removal are more thorough, which is conducive to its market promotion. In order to give the coating low thermal conductivity and strong infrared shielding, the present invention modifies the hollow silica microspheres to prepare composite hollow silica microspheres as fillers, and in situ grows cesium-doped tungsten bronze nanoparticles on the surface of the hollow silica microspheres by a solvent thermal method to obtain pretreated hollow silica microspheres, thereby improving the thermal and infrared shielding effects of the coating. In order to further improve the uniformity of the dispersion of the pretreated hollow silica microspheres in the coating and improve its interface compatibility with the coating, the pretreated hollow silica microspheres are treated with an epoxy silane coupling agent to obtain epoxidized hollow silica, and then the epoxy-hydroxyl reaction is used to graft a hydroxyl-terminated ternary flame retardant chain extender, thereby greatly improving the various properties of the coating and effectively improving the service life of the coating. DETAILED DESCRIPTION

[0031] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] It should be noted that if the embodiments of the present invention involve directional indications such as up, down, left, right, front, and back, the directional indication is only used to explain a specific posture such as the relative position relationship between the components, the movement status, etc. If the specific posture changes, the directional indication will also change accordingly. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the protection scope required by the present invention.

[0033] The technical solution of the present invention is further described in detail below in conjunction with specific embodiments. It should be understood that the following embodiments are only used to explain the present invention, and are not used to limit the present invention.

[0034] Example 1: A method for preparing a mesoporous thermal insulation coating having an infrared heat shielding function, comprising the following steps:

[0035] S1: mixing an emulsified aqueous solution, a surfactant, γ-aminopropyltriethoxysilane, a fluorine monomer, and isobutyltriethoxysilane to obtain a solution A;

[0036] The emulsified aqueous solution is prepared by compounding an emulsifier and deionized water in a mass ratio of 1:15; in terms of mass fractions, the raw material composition of the solution A is: 10 parts of the emulsified aqueous solution, 1 part of a surfactant, 2 parts of γ-aminopropyltriethoxysilane, 1 part of a fluorine monomer, and 2 parts of isobutyltriethoxysilane;

[0037] S2: Mix the polyurethane prepolymer and solution A, raise the temperature to 70°C and keep the temperature for 8 hours, add the chain extender, keep the temperature for 2 hours, add the emulsified aqueous solution and stir for 2 hours, adjust the pH to 7, and obtain a polyurethane-organosilicon emulsion;

[0038] The raw material composition of the polyurethane-organic silicone emulsion is as follows: 12 parts of polyurethane prepolymer, 5 parts of solution A, 4 parts of chain extender, and 20 parts of emulsified aqueous solution, in parts by mass;

[0039] The preparation of the polyurethane prepolymer comprises the following steps: mixing 6g of polytetrahydrofuran, 4g of castor oil, and 12g of 4,4'-methylene diphenyl diisocyanate, adding 3g of polyester diol and 2g of dimethylol propionic acid, heating to 65°C and keeping the temperature for 10h to obtain a polyurethane prepolymer;

[0040] The chain extender is a hydroxyl-terminated ternary flame retardant chain extender, and the preparation thereof comprises the following steps:

[0041] (1) Mix 2.1 g of monoethanolamine borate and 50 mL of anhydrous ethanol, add 2.8 g of 2,4-dihydroxybenzaldehyde, keep warm at 18°C ​​for 12 h, filter under reduced pressure, wash, and dry to obtain a boron-containing Schiff base compound;

[0042] (2) 4.5 g of a boron-containing Schiff base compound and 400 mL of N,N-dimethylformamide were mixed, the temperature was raised to 63 °C and kept warm for 30 min, 4.3 g of DOPO was added, the temperature was kept warm for 10 h, rotary evaporation, washing, and recrystallization were performed to obtain a Schiff base compound containing NPB;

[0043] (3) 4.23 g of a Schiff base compound containing NPB and 1.05 g of diethanolamine were mixed, kept at 38° C. for 2 h, washed and recrystallized to obtain an intermediate preparation; under a nitrogen atmosphere, 4.92 g of the intermediate preparation, 5 g of 4,4'-methylenediphenyl diisocyanate, and 500 mL of N,N-dimethylformamide were mixed, kept at 58° C. for 3 h, washed and recrystallized to obtain a hydroxyl-terminated ternary flame retardant chain extender;

[0044] S3: mixing the mesoporous material, the dispersant, anhydrous ethanol and deionized water to obtain a mesoporous slurry;

[0045] The raw material composition of the mesoporous slurry is as follows: 5 parts of mesoporous material, 1 part of dispersant, 10 parts of anhydrous ethanol, and 15 parts of deionized water.

[0046] The mesoporous material is hollow silica microspheres, and the preparation thereof comprises the following steps:

[0047] 40 mL of 6.6 mmol / L nitric acid and 0.48 mL of phenyltrimethoxysilane were mixed, heated to 58°C and kept in a water bath for 5 min, 16 mL of 29% ammonia water was added, stirred for 1 h, centrifuged, washed, dried, heated to 200°C and kept for 2 h, and then heated to 660°C and calcined for 16 h to obtain hollow silica microspheres;

[0048] S4: hollow glass microspheres, ethanol, and deionized water are mixed, ultrasonically dispersed, mesoporous slurry, filler, calcium carbonate, and dispersant are added, ground, polyurethane-organic silicon emulsion is added, and then additives are added and stirred to obtain a mesoporous thermal insulation coating with infrared heat shielding function;

[0049] The raw material composition of the thermal insulation coating is as follows, by weight: 1 part of hollow glass microspheres, 10 parts of ethanol, 20 parts of deionized water, 1 part of mesoporous slurry, 2 parts of filler, 1 part of calcium carbonate, 1 part of dispersant, 18 parts of polyurethane-organic silicon emulsion, and 3 parts of additives;

[0050] The filler is a composite hollow silica microsphere, and the preparation includes the following steps:

[0051] 1) 1 g of hollow silica microspheres and 32 g of anhydrous ethanol were mixed, ultrasonically dispersed for 1 h, 20 mL of 0.5 mol / L tungstate sol, 20 mL of 0.05 mol / L cesium carbonate solution, and 20 mL of 1.1 mol / L citric acid solution were added, and the mixture was transferred to a reactor, kept at 190 ° C for 72 h, washed with water, washed with alcohol, centrifuged, and dried to obtain pretreated hollow silica microspheres;

[0052] 2) Mix 2.5 mL of 3-glyceropropyltrimethoxysilane, 40 mL of ethanol, 10 mL of deionized water, and 0.6 g of pretreated hollow silica microspheres, adjust the pH value of the solution to 4, stir for 22 hours, centrifuge, wash, and dry to obtain epoxidized hollow silica microspheres;

[0053] 3) Mix 2.5 g of hydroxyl-terminated ternary flame retardant chain extender, 1.2 g of epoxidized hollow silica microspheres, 15 mL of chloroform, and 0.8 g of Amberlyst-15 ion exchange resin, stir ultrasonically, heat to 55 °C and keep warm for 3 h, filter, and rotary evaporate to obtain composite hollow silica microspheres.

[0054] Example 2: A method for preparing a mesoporous thermal insulation coating having an infrared heat shielding function, comprising the following steps:

[0055] S1: mixing an emulsified aqueous solution, a surfactant, γ-aminopropyltriethoxysilane, a fluorine monomer, and isobutyltriethoxysilane to obtain a solution A;

[0056] The emulsified aqueous solution is prepared by mixing an emulsifier and deionized water in a mass ratio of 1:15; in terms of mass fractions, the raw material composition of the solution A is: 13 parts of the emulsified aqueous solution, 2 parts of a surfactant, 3 parts of γ-aminopropyltriethoxysilane, 1.5 parts of a fluorine monomer, and 3 parts of isobutyltriethoxysilane;

[0057] S2: Mix the polyurethane prepolymer and solution A, heat to 73°C and keep the temperature for 7 hours, add the chain extender, keep the temperature for 3 hours, add the emulsified aqueous solution and stir for 2.5 hours, adjust the pH to 7.5, and obtain a polyurethane-silicone emulsion;

[0058] The raw material composition of the polyurethane-organic silicone emulsion is as follows: 15 parts of polyurethane prepolymer, 8 parts of solution A, 6 parts of chain extender, and 23 parts of emulsified aqueous solution, in parts by mass;

[0059] The preparation of the polyurethane prepolymer comprises the following steps: mixing 6g of polytetrahydrofuran, 4g of castor oil, and 12g of 4,4'-methylene diphenyl diisocyanate, adding 3g of polyester diol and 2g of dimethylol propionic acid, heating to 65°C and keeping the temperature for 10h to obtain a polyurethane prepolymer;

[0060] The chain extender is a hydroxyl-terminated ternary flame retardant chain extender, and the preparation thereof comprises the following steps:

[0061] (1) Mix 2.1 g of monoethanolamine borate and 50 mL of anhydrous ethanol, add 2.8 g of 2,4-dihydroxybenzaldehyde, keep warm at 20°C for 11 h, filter under reduced pressure, wash, and dry to obtain a boron-containing Schiff base compound;

[0062] (2) 4.5 g of a boron-containing Schiff base compound and 400 mL of N,N-dimethylformamide were mixed, the temperature was raised to 65 °C and kept warm for 25 min, 4.3 g of DOPO was added, the temperature was kept warm for 11 h, and the mixture was rotary evaporated, washed, and recrystallized to obtain a Schiff base compound containing NPB;

[0063] (3) 4.23 g of a Schiff base compound containing NPB and 1.05 g of diethanolamine were mixed, kept at 38°C for 2 h, washed and recrystallized to obtain an intermediate preparation; under a nitrogen atmosphere, 4.92 g of the intermediate preparation, 5 g of 4,4'-methylenediphenyl diisocyanate, and 500 mL of N,N-dimethylformamide were mixed, kept at 60°C for 2.5 h, washed and recrystallized to obtain a hydroxyl-terminated ternary flame retardant chain extender;

[0064] S3: mixing the mesoporous material, the dispersant, anhydrous ethanol and deionized water to obtain a mesoporous slurry;

[0065] The raw material composition of the mesoporous slurry is as follows: 7 parts of mesoporous material, 2 parts of dispersant, 15 parts of anhydrous ethanol, and 21 parts of deionized water.

[0066] The mesoporous material is hollow silica microspheres, and the preparation thereof comprises the following steps:

[0067] 40 mL of 6.6 mmol / L nitric acid and 0.48 mL of phenyltrimethoxysilane were mixed, heated to 60°C and kept in a water bath for 4 min, 16 mL of 29% ammonia water was added, stirred for 1.5 h, centrifuged, washed, dried, heated to 200°C and kept for 2 h, and then heated to 660°C and calcined for 16 h to obtain hollow silica microspheres;

[0068] S4: hollow glass microspheres, ethanol, and deionized water are mixed, ultrasonically dispersed, mesoporous slurry, filler, calcium carbonate, and dispersant are added, ground, polyurethane-organic silicon emulsion is added, and then additives are added and stirred to obtain a mesoporous thermal insulation coating with infrared heat shielding function;

[0069] The raw material composition of the thermal insulation coating is as follows, by weight: 3 parts of hollow glass microspheres, 13 parts of ethanol, 25 parts of deionized water, 3 parts of mesoporous slurry, 5 parts of filler, 4 parts of calcium carbonate, 3 parts of dispersant, 20 parts of polyurethane-organic silicon emulsion, and 4 parts of additives;

[0070] The filler is a composite hollow silica microsphere, and the preparation includes the following steps:

[0071] 1) 1 g of hollow silica microspheres and 32 g of anhydrous ethanol were mixed, ultrasonically dispersed for 1.5 h, 20 mL of 0.5 mol / L tungstate sol, 20 mL of 0.05 mol / L cesium carbonate solution, and 20 mL of 1.1 mol / L citric acid solution were added, and the mixture was transferred to a reactor, kept at 195 ° C for 71 h, washed with water, washed with alcohol, centrifuged, and dried to obtain pretreated hollow silica microspheres;

[0072] 2) Mix 2.5 mL of 3-glyceropropyltrimethoxysilane, 40 mL of ethanol, 10 mL of deionized water, and 0.6 g of pretreated hollow silica microspheres, adjust the pH value of the solution to 4, stir for 23 h, centrifuge, wash, and dry to obtain epoxidized hollow silica microspheres;

[0073] 3) Mix 2.5 g of hydroxyl-terminated ternary flame retardant chain extender, 1.2 g of epoxidized hollow silica microspheres, 15 mL of chloroform, and 0.8 g of Amberlyst-15 ion exchange resin, stir ultrasonically, heat to 58 °C and keep warm for 2.5 h, filter, and rotary evaporate to obtain composite hollow silica microspheres.

[0074] Example 3: A method for preparing a mesoporous thermal insulation coating having an infrared heat shielding function, comprising the following steps:

[0075] S1: mixing an emulsified aqueous solution, a surfactant, γ-aminopropyltriethoxysilane, a fluorine monomer, and isobutyltriethoxysilane to obtain a solution A;

[0076] The emulsified aqueous solution is prepared by mixing an emulsifier and deionized water in a mass ratio of 1:15; in terms of mass fractions, the raw material composition of the solution A is: 15 parts of the emulsified aqueous solution, 3 parts of a surfactant, 4 parts of γ-aminopropyltriethoxysilane, 2 parts of a fluorine monomer, and 4 parts of isobutyltriethoxysilane;

[0077] S2: Mix the polyurethane prepolymer and solution A, heat to 75°C and keep the temperature for 6 hours, add the chain extender, keep the temperature for 4 hours, add the emulsified aqueous solution and stir for 2 hours, adjust the pH to 8, and obtain a polyurethane-organic silicone emulsion;

[0078] The raw material composition of the polyurethane-organic silicone emulsion is as follows: 17 parts of polyurethane prepolymer, 10 parts of solution A, 8 parts of chain extender, and 25 parts of emulsified aqueous solution, in parts by mass;

[0079] The preparation of the polyurethane prepolymer comprises the following steps: mixing 6g of polytetrahydrofuran, 4g of castor oil, and 12g of 4,4'-methylene diphenyl diisocyanate, adding 3g of polyester diol and 2g of dimethylol propionic acid, heating to 65°C and keeping the temperature for 10h to obtain a polyurethane prepolymer;

[0080] The chain extender is a hydroxyl-terminated ternary flame retardant chain extender, and the preparation thereof comprises the following steps:

[0081] (1) Mix 2.1 g of monoethanolamine borate and 50 mL of anhydrous ethanol, add 2.8 g of 2,4-dihydroxybenzaldehyde, keep warm at 25°C for 10 h, filter under reduced pressure, wash, and dry to obtain a boron-containing Schiff base compound;

[0082] (2) 4.5 g of a boron-containing Schiff base compound and 400 mL of N,N-dimethylformamide were mixed, the temperature was raised to 66 °C and kept warm for 20 min, 4.3 g of DOPO was added, the temperature was kept warm for 12 h, and the mixture was rotary evaporated, washed, and recrystallized to obtain a Schiff base compound containing NPB;

[0083] (3) 4.23 g of a Schiff base compound containing NPB and 1.05 g of diethanolamine were mixed, kept at 42°C for 1 h, washed and recrystallized to obtain an intermediate preparation; under a nitrogen atmosphere, 4.92 g of the intermediate preparation, 5 g of 4,4'-methylenediphenyl diisocyanate, and 500 mL of N,N-dimethylformamide were mixed, kept at 62°C for 2 h, washed and recrystallized to obtain a hydroxyl-terminated ternary flame retardant chain extender;

[0084] S3: mixing the mesoporous material, the dispersant, anhydrous ethanol and deionized water to obtain a mesoporous slurry;

[0085] The raw material composition of the mesoporous slurry is as follows: 10 parts of mesoporous material, 3 parts of dispersant, 18 parts of anhydrous ethanol, and 27 parts of deionized water.

[0086] The mesoporous material is hollow silica microspheres, and the preparation thereof comprises the following steps:

[0087] 40 mL of 6.6 mmol / L nitric acid and 0.48 mL of phenyltrimethoxysilane were mixed, heated to 62°C and kept in a water bath for 3 min, 16 mL of 29% ammonia water was added, stirred for 2 h, centrifuged, washed, dried, heated to 200°C and kept for 2 h, and then heated to 660°C and calcined for 16 h to obtain hollow silica microspheres;

[0088] S4: hollow glass microspheres, ethanol, and deionized water are mixed, ultrasonically dispersed, mesoporous slurry, filler, calcium carbonate, and dispersant are added, ground, polyurethane-organic silicon emulsion is added, and then additives are added and stirred to obtain a mesoporous thermal insulation coating with infrared heat shielding function;

[0089] The raw material composition of the thermal insulation coating is as follows, by mass: 5 parts of hollow glass microspheres, 15 parts of ethanol, 30 parts of deionized water, 5 parts of mesoporous slurry, 10 parts of filler, 6 parts of calcium carbonate, 5 parts of dispersant, 24 parts of polyurethane-organic silicon emulsion, and 7 parts of additives;

[0090] The filler is a composite hollow silica microsphere, and the preparation includes the following steps:

[0091] 1) 1 g of hollow silica microspheres and 32 g of anhydrous ethanol were mixed, ultrasonically dispersed for 2 h, 20 mL of 0.5 mol / L tungstate sol, 20 mL of 0.05 mol / L cesium carbonate solution, and 20 mL of 1.1 mol / L citric acid solution were added, and the mixture was transferred to a reactor, kept at 200 ° C for 70 h, washed with water, washed with alcohol, centrifuged, and dried to obtain pretreated hollow silica microspheres;

[0092] 2) Mix 2.5 mL of 3-glyceropropyltrimethoxysilane, 40 mL of ethanol, 10 mL of deionized water, and 0.6 g of pretreated hollow silica microspheres, adjust the pH value of the solution to 4, stir for 24 hours, centrifuge, wash, and dry to obtain epoxidized hollow silica microspheres;

[0093] 3) Mix 2.5 g of hydroxyl-terminated ternary flame retardant chain extender, 1.2 g of epoxidized hollow silica microspheres, 15 mL of chloroform, and 0.8 g of Amberlyst-15 ion exchange resin, stir ultrasonically, heat to 60 °C and keep warm for 2 h, filter, and rotary evaporate to obtain composite hollow silica microspheres.

[0094] Comparative Example 1: Taking Example 3 as the control group, hollow silica microspheres were used to replace the composite hollow silica microspheres, and the other processes were normal.

[0095] Comparative Example 2: Using Example 3 as the control group, 1,4-butanediol was used to replace the hydroxyl-terminated ternary flame retardant chain extender, and other processes were normal.

[0096] The auxiliary agent used in the examples and comparative examples is a defoaming agent; the preparation of the tungstate sol in the examples and comparative examples includes the following steps:

[0097] Sodium tungstate and deionized water are mixed to prepare 0.5 mol / L sodium tungstate solution, and then passed through a cation exchange resin to obtain tungstate sol.

[0098] Sources of raw materials used (for demonstration purposes only):

[0099] Defoamer TL-J20: Shenzhen Jihechang New Materials Co., Ltd.; Emulsifier NP-10: Shandong Yukang Chemical Co., Ltd.; Surfactant JS6602, polyester diol JS0406: Hubei Jusheng Technology Co., Ltd.; Dispersant NNOT25140, γ-aminopropyl triethoxysilane S15028, fluorine monomer S49554, Amberlyst-15 ion exchange resin Y52434: Shanghai Yuanye Biotechnology Co., Ltd.; Hollow glass microspheres 002: Hebei Wensheng New Materials Technology Co., Ltd.; Monoethanolamine borate (99%): Wuhan Kanos Technology Co., Ltd.; Phenyl trimethoxysilane ZH-1104: Wuhan Beiguofeng Chemical Co., Ltd.; Isobutyl triethoxysilane I 168015, polytetrahydrofuran P118599, castor oil C110663, 4,4'-methylene diphenyl diisocyanate M106783, dihydroxymethylpropionic acid B104539, 2,4-dihydroxybenzaldehyde D106474, N,N-dimethylformamide D111999, DOPO (9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide) D102416, diethanolamine D112361, sodium tungstate S431260, cesium carbonate C105061, citric acid C639638, 3-glyceropropyltrimethoxysilane G107576: Aladdin reagent; anhydrous ethanol, nitric acid, ammonia water, calcium carbonate, chloroform, analytical grade: Sinopharm reagent.

[0100] Performance test: The coatings prepared in the embodiments and comparative examples were tested:

[0101] Thermal conductivity: Tested with a thermal conductivity tester and measured using the isotropic method;

[0102] Infrared shielding property: Apply the coating to 100µm of the glass surface with specifications of 160mm in length, 200mm in width and 3mm in thickness, and cure to obtain a sample. Use a UV-visible spectrophotometer to test the transmittance at 800-1100nm;

[0103] Flame retardancy: The coating was applied to a 100µm surface of a glass surface with a specification of 160mm in length, 200mm in width and 3mm in thickness, and cured to obtain a sample, which was then subjected to the UL-94 vertical burning test for flame retardancy;

[0104] Self-healing rate: The coating was applied to a 100µm surface of a glass surface with a specification of 160mm in length, 200mm in width and 3mm in thickness, and a sample was obtained by curing. A scratch with a length of 1mm, a width of 2µm and a depth of 100µm was made on the sample, and then the sample was kept at 60℃ for 6h. The length of the scratch was observed with an electron microscope. The self-healing rate was (L 初始 -L 现有 ) / L 初始 ×100%; the results are shown in Table 1;

[0105] Table 1

[0106]

[0107] The present invention provides a mesoporous thermal insulation coating with infrared heat shielding function and a preparation method thereof. The components thereof are optimized and designed. The coating formed after the prepared thermal insulation coating is cured is a multifunctional coating with low thermal conductivity, strong infrared shielding, high flame retardancy and self-repairing properties.

[0108] By comparing Example 3 with Comparative Example 1 and Comparative Example 2, it can be seen that in order to give the coating excellent thermal insulation, hollow silica microspheres are selected as mesoporous materials in the present invention, which are prepared by a two-step method of first hydrolyzing and condensing phenyltrimethoxysilane and then calcining to remove impurities. Compared with the common double template method, the simplified process and template removal are more thorough, which is conducive to its market promotion; in order to give the coating low thermal conductivity and strong infrared shielding properties, the present invention modifies the hollow silica microspheres to prepare composite hollow silica microspheres as fillers, and adopts solvent Cesium-doped tungsten bronze nanoparticles were in situ grown on the surface of hollow silica microspheres by a thermal method to obtain pretreated hollow silica microspheres, thereby improving the heat and infrared shielding effects of the coating. In order to further improve the uniformity of dispersion of the pretreated hollow silica microspheres in the coating and improve their interfacial compatibility with the coating, they were treated with an epoxy silane coupling agent to obtain epoxidized hollow silica, and then the hydroxyl-terminated ternary flame retardant chain extender was grafted by epoxy-hydroxyl reaction, thereby greatly improving the various properties of the coating and effectively increasing the service life of the coating.

[0109] By comparing Example 3 with Comparative Example 2, it can be seen that in order to improve the corrosion resistance of the thermal insulation coating, the present invention selects a polyurethane-organic silicon emulsion as the base material of the coating, and in order to make the coating formed by the thermal insulation coating have excellent resistance to mechanical damage and flame retardancy and fire resistance, to solve the problems that the coating is easily damaged during long-term use and produces microcracks, and exposure to media such as air and moisture will accelerate the diffusion of microcracks, causing the protective performance of the coating to significantly decrease. In the present invention, a hydroxyl-terminated ternary flame retardant chain extender is used to extend the polyurethane prepolymer to prepare a highly flame retardant and self-repairing polyurethane-organic silicon emulsion, wherein the hydroxyl-terminated ternary flame retardant chain extender is made of monoethanolamine borate and 2,4-dihydroxybenzaldehyde as raw materials. , obtaining a boron-containing Schiff base compound, which is then further reacted with DOPO to generate a Schiff base compound containing NPB, thereby greatly improving the flame retardancy and smoke suppression of the coating; then, using diethanolamine and a Schiff base compound containing NPB as raw materials, a nitrogen-boron-containing internally coordinated compound with multiple dynamic bonds at one end of an amino group and a hydroxyl group at the other end is prepared as an intermediate preparation, wherein the generated borate ester bond and multiple dynamic bonds such as Schiff base construct a complex self-healing network, thereby improving the self-healing ability of the coating; the intermediate preparation is reacted with 4,4'-methylene diphenyl diisocyanate to prepare a hydroxyl-terminated compound with multiple dynamic bonds and containing N, P, and B ternary synergistic flame retardant, namely a hydroxyl-terminated ternary flame retardant chain extender.

[0110] The above descriptions are only embodiments of the present invention and are not intended to limit the patent scope of the present invention. All equivalent structural changes made using the present invention specification under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included in the patent protection scope of the present invention.

Claims

1. A method for preparing a mesoporous thermal insulation coating having an infrared heat shielding function, characterized in that: The following steps are involved: S1: mixing an emulsified aqueous solution, a surfactant, γ-aminopropyltriethoxysilane, a fluorine monomer, and isobutyltriethoxysilane to obtain a solution A; S2: Mix the polyurethane prepolymer and solution A, heat to 70-75°C and keep warm for 6-8 hours, add the chain extender, keep warm for 2-4 hours, add the emulsified aqueous solution and stir for 2-3 hours, adjust the pH to 7-8, and obtain a polyurethane-organic silicone emulsion; S3: mixing the mesoporous material, the dispersant, anhydrous ethanol and deionized water to obtain a mesoporous slurry; S4: hollow glass microspheres, ethanol, and deionized water are mixed, ultrasonically dispersed, mesoporous slurry, filler, calcium carbonate, and dispersant are added, ground, polyurethane-organic silicon emulsion is added, and then additives are added and stirred to obtain a mesoporous thermal insulation coating with infrared heat shielding function; The chain extender is a hydroxyl-terminated ternary flame retardant chain extender, and the preparation thereof comprises the following steps: (1) mixing monoethanolamine borate and anhydrous ethanol, adding 2,4-dihydroxybenzaldehyde, keeping the mixture at 18-25° C. for 10-12 hours, filtering under reduced pressure, washing, and drying to obtain a boron-containing Schiff base compound; (2) mixing a boron-containing Schiff base compound and N,N-dimethylformamide, heating to 63-66° C. and keeping the temperature for 20-30 min, adding DOPO, and keeping the temperature for 10-12 h, rotary evaporating, washing, and recrystallizing to obtain a Schiff base compound containing NPB; (3) Mixing a Schiff base compound containing NPB and diethanolamine, keeping the mixture at 38-42° C. for 1-2 hours, washing and recrystallizing the mixture to obtain an intermediate preparation; in a nitrogen atmosphere, mixing the intermediate preparation, 4,4'-methylenediphenyl diisocyanate, and N,N-dimethylformamide, keeping the mixture at 58-62° C. for 2-3 hours, washing and recrystallizing the mixture to obtain a hydroxyl-terminated ternary flame retardant chain extender.

2. The method for preparing a mesoporous thermal insulation coating having an infrared heat shielding function according to claim 1, characterized in that: The emulsified aqueous solution is prepared by compounding an emulsifier and deionized water in a mass ratio of 1:15; in terms of mass parts, the raw material composition of solution A is: 10-15 parts of emulsified aqueous solution, 1-3 parts of surfactant, 2-4 parts of γ-aminopropyltriethoxysilane, 1-2 parts of fluorine monomer, and 2-4 parts of isobutyltriethoxysilane.

3. The method for preparing a mesoporous thermal insulation coating having an infrared heat shielding function according to claim 1, characterized in that: The preparation of the polyurethane prepolymer comprises the following steps: mixing polytetrahydrofuran, castor oil and 4,4'-methylene diphenyl diisocyanate, adding polyester diol and dimethylol propionic acid, heating to 65-70° C. and keeping the temperature for 8-10 hours to obtain the polyurethane prepolymer.

4. The method for preparing a mesoporous thermal insulation coating having an infrared heat shielding function according to claim 1, characterized in that: The raw material composition of the polyurethane-silicone emulsion is, by weight, 12-17 parts of polyurethane prepolymer, 5-10 parts of solution A, 4-8 parts of chain extender, and 20-25 parts of emulsified aqueous solution; the raw material composition of the mesoporous slurry is, by weight, 5-10 parts of mesoporous material, 1-3 parts of dispersant, 10-18 parts of anhydrous ethanol, and 15-27 parts of deionized water.

5. The method for preparing a mesoporous thermal insulation coating having an infrared heat shielding function according to claim 1, characterized in that: The raw material composition of the thermal insulation coating is as follows, in parts by mass: 1-5 parts of hollow glass microspheres, 10-15 parts of ethanol, 20-30 parts of deionized water, 1-5 parts of mesoporous slurry, 2-10 parts of filler, 1-6 parts of calcium carbonate, 1-5 parts of dispersant, 18-24 parts of polyurethane-silicone emulsion, and 3-7 parts of additives.

6. The method for preparing a mesoporous thermal insulation coating having an infrared heat shielding function according to claim 1, characterized in that: The auxiliary agent is a composite of one or more of a film-forming auxiliary agent, a defoaming agent, an anti-settling agent, a leveling agent, a wetting agent, and a pH regulator.

7. The method for preparing a mesoporous thermal insulation coating having an infrared heat shielding function according to claim 1, characterized in that: The mesoporous material is hollow silica microspheres, and the preparation thereof comprises the following steps: Mix nitric acid and phenyltrimethoxysilane, heat to 58-62°C and keep in a water bath for 3-5 minutes, add ammonia water, stir for 1-2 hours, centrifuge, wash, dry, heat to 200°C and keep for 2 hours, then heat to 660°C and calcine for 16 hours to obtain hollow silica microspheres.

8. The method for preparing a mesoporous thermal insulation coating having an infrared heat shielding function according to claim 1, characterized in that: The filler is a composite hollow silica microsphere, and the preparation includes the following steps: 1) Mix the hollow silica microspheres and anhydrous ethanol, perform ultrasonic dispersion for 1-2 hours, add tungstate sol, cesium carbonate solution and citric acid solution, transfer to a reaction kettle, keep at 190-200° C. for 70-72 hours, wash with water, wash with alcohol, centrifuge and dry to obtain pretreated hollow silica microspheres; 2) 3-glyceropropyltrimethoxysilane, ethanol and deionized water are mixed, and the pretreated hollow silica microspheres are added, and ultrasonic stirring is performed for 1-2 hours, and the pH value of the solution is adjusted to 4, and stirred for 22-24 hours, and centrifuged, washed and dried to obtain epoxidized hollow silica microspheres; 3) Mix the hydroxyl-terminated ternary flame retardant chain extender, epoxidized hollow silica microspheres, chloroform, and Amberlyst-15 ion exchange resin, stir ultrasonically for 1-2 hours, heat to 55-65° C. and keep warm for 2-3 hours, filter, and rotary evaporate to obtain composite hollow silica microspheres.

9. A mesoporous thermal insulation coating with infrared heat shielding function, characterized in that: The compound is prepared by the preparation method according to any one of claims 1 to 8.

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