CN116554784A - Epoxy modified methylphenyl organic silicon aerogel heat insulation coating and preparation method thereof - Google Patents

Abstract

The invention provides an epoxy modified methylphenyl organic silicon aerogel heat-insulating coating and a preparation method thereof. The epoxy modified methylphenyl organic silicon aerogel heat insulation coating is mainly prepared from the following raw materials: 20-58 parts of epoxy modified methylphenyl organic silicon resin, 2-6 parts of amino resin, 5-20 parts of aerogel composite heat insulation powder, 2-10 parts of modified aerogel, 1-10 parts of hollow glass beads, 1-5 parts of mica powder, 10-20 parts of water, 0.1-2 parts of dispersing agent, 0.1-1 part of defoaming agent, 0.1-1 part of leveling agent, 1-3 parts of silane coupling agent, 0.1-2 parts of antifreezing agent, 0.1-0.5 part of water retention agent and 0.1-0.5 part of antibacterial agent, wherein the inner layer structure of the aerogel composite heat insulation powder is that pressure-resistant silica hollow nano microspheres are filled in aerogel holes. The prepared epoxy modified methylphenyl organic silicon aerogel heat-insulating coating fully exerts the heat-insulating property of the aerogel, so that the heat-insulating property, heat resistance and adhesive force of the aerogel are good.

Description

A kind of epoxy-modified methylphenyl organosilicon airgel thermal insulation coating and preparation method thereof

technical field

The invention relates to the technical field of high temperature resistance and heat insulation of energy and chemical equipment, in particular to an epoxy-modified methylphenyl-modified organosilicon airgel heat-insulation coating and a preparation method thereof.

Background technique

The energy and chemical industry has important strategic significance to the country. Driven by "double carbon", reducing carbon emissions is imminent for the energy and chemical industry. The energy waste of some high-temperature equipment and high-temperature pipelines in the energy and chemical industry is serious. The use of heat insulation materials can effectively reduce energy waste and achieve the purpose of energy saving and carbon reduction. At present, the commonly used thermal insulation materials mainly include: glass wool, expanded perlite, airgel felt, micro-nano insulation board, rock wool and some organic foam boards. However, these materials are mostly used in regular parts of equipment, and special-shaped parts cannot be fully covered by the above materials.

The coating has the characteristics of easy construction and coating of special-shaped parts. At present, although there are related reports on heat insulation through coatings in the energy and chemical industry, the effects are not satisfactory, mainly because the performance of anti-corrosion, adhesion, high temperature resistance, heat insulation, and thermal shock resistance cannot be taken into account. Inorganic film formers have good high temperature resistance, but poor thermal shock resistance. The silicone resin in the organic film former has a certain high temperature resistance, but its adhesion is poor, and the poor adhesion will affect the service life of the prepared coating. Airgel is the filler with the best thermal insulation properties. However, airgel has a large specific surface area and unstable nanopore structure. In the coating system, it is easy to disperse unevenly, easily cause problems such as cracking and porous structure collapse. Therefore, there are few related coatings that can exert the thermal insulation performance of airgel at present. reports. Due to the rich pore structure of airgel, its thermal conductivity is as low as 0.01W/(m K), but when the pore structure is destroyed, the thermal conductivity is much greater than 0.07W/(m K), and the thermal insulation performance is greatly reduced. .

Resins are often used in the preparation of coatings. Different groups of resins have different properties, and the performance of the prepared coatings varies greatly. CN 102559048 A discloses a preparation method and product of an epoxy-modified organic silicon insulating heat-conducting and high-temperature-resistant coating, which has better insulating performance due to the introduction of epoxy resin. CN101935498A uses silicone resin, modified silicone resin, epoxy resin, phenolic resin, amino resin, etc. to prepare silicone anti-corrosion coating, which has good adhesion and corrosion resistance. CN104371506A Mix resin and silicon oxide aerogel to prepare cathodic stripping-resistant coating and coating with good adhesion. However, due to the fact that existing studies only use resins to prepare coatings or simply use a combination of resins carrying different groups to prepare coatings, this will lead to the following problems: (1) the high temperature resistance of the prepared coatings is not excellent enough; (2) the mixing of different resins Although it can increase the function of the coating, at the same time, due to the introduction of various resins, it will be difficult to mix or take a long time to mix, and the production cycle will become longer; (3) Although the introduction of airgel and other materials with better high temperature resistance to make coatings, However, the airgel is not pretreated, which makes it difficult to disperse the airgel, and in some coating systems, the pores of the airgel are easily destroyed, making it difficult to maximize its thermal insulation performance.

Contents of the invention

The first aspect of the present invention is to provide an epoxy-modified methylphenyl silicone airgel heat-insulating coating, which is mainly made of the following raw materials: 20-58 parts of epoxy-modified methylphenyl silicone resin , 2-6 parts of amino resin, 5-20 parts of airgel composite heat insulation powder, 2-10 parts of modified airgel, 1-10 parts of hollow glass microspheres, 1-5 parts of mica powder, 10- 20 parts, 0.1-2 parts of dispersant, 0.1-1 part of defoamer, 0.1-1 part of leveling agent, 1-3 parts of silane coupling agent, 0.1-2 parts of antifreeze, 0.1-0.5 parts of water retention agent, antibacterial 0.1-0.5 parts, the inner layer structure of the airgel composite thermal insulation powder is airgel holes filled with pressure-resistant silicon dioxide hollow nanospheres.

The airgel in the airgel composite thermal insulation powder is silicon dioxide airgel modified by a methyl-containing hydrophobic modifier. Specifically, the hydrophobic modifying agent containing methyl group is one or more of trimethyldisilazane (TMCS), hexamethyldisilazane (HMDS) and hexamethyldisiloxane (HMDSO) The combination.

The airgel composite thermal insulation powder includes the following components in parts by weight: 60-80 parts of airgel and 15-25 parts of pressure-resistant silicon dioxide hollow nano microspheres.

The amounts of the raw materials added are: epoxy-modified methylphenyl silicone resin, amino resin, airgel composite heat-insulating powder, modified airgel, hollow glass microspheres, mica powder, water, dispersed agent, defoamer, leveling agent, silane coupling agent, antifreeze, water retaining agent, antibacterial agent.

In the present invention, the epoxy-modified methylphenyl silicone resin is SH-9607 from Hubei New Sihai.

The amino resin is selected from but not limited to Cytec CYMEL 325, CYMEl 380, CYMEL 303LF;

The density range of the hollow glass microspheres is but not limited to 0.15g/cm ³ to 0.6g/cm ³ ;

The particle size of the mica powder is but not limited to 500-5000 mesh;

The dispersant is selected from but not limited to sulfonate, octadecylamine acetate, polyethylene glycol polyol, phosphate ester salt type polymer, oleyl amino oleate;

The defoamer is selected from but not limited to polysiloxanes, modified polysiloxanes, higher alcohols, and polyether defoamers. The leveling agent is selected from but not limited to acrylics, silicones, and fluorocarbons.

The silane coupling agent is selected from but not limited to 3-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, 3-(2,3-glycidoxy)propyltrimethoxy Silane, γ-(methacryloyloxy)propyltrimethoxysilane.

The antifreezing agent is selected from but not limited to ethylene glycol, propylene glycol, urea, thiourea and the like.

The water retaining agent is selected from but not limited to starch, hydroxymethyl cellulose, polyvinyl alcohol, ethylene glycol, propylene glycol and the like.

The antibacterial agent is selected from but not limited to organic bromines, organic amines, and guanidine triazines.

A second aspect of the present invention provides a method for preparing an epoxy-modified methylphenyl silicone airgel heat-insulating coating, comprising the following steps:

1) Weighing epoxy-modified methylphenyl silicone resin, amino resin, dispersant, and airgel composite heat-insulating powder, adding them to water in sequence, and grinding to obtain a grinding slurry;

2) Add glass microspheres, defoamer, leveling agent, silane coupling agent successively to the grinding slurry obtained in 1), and stir and mix evenly;

3) Add modified airgel, antifreeze agent, water retaining agent, and antifungal agent to the uniformly mixed liquid in 2) and stir to prepare epoxy modified methylphenyl silicone airgel thermal insulation coating .

The airgel composite thermal insulation powder in the step 1) is prepared by the following method:

(1) Add tetraethyl orthosilicate, water, ethanol and hydrochloric acid to carry out hydrolysis, obtain tetraethyl orthosilicate hydrolyzate;

(2) Rapidly stirring and adding an alkali solution to the obtained mixed solution to adjust the pH of the system, then adding pressure-resistant silica hollow nanospheres into the mixed solution, and solidifying to obtain a composite gel;

(3) breaking the cured composite gel into small particles, and then placing it in an ethanol solvent for solvent replacement;

(4) placing the composite gel after solvent replacement in a methyl-containing hydrophobic modifier for modification;

(5) The liquid is separated, and then the composite gel is dried to prepare the airgel composite thermal insulation powder.

In the step 1), the grinding speed is 3000r/min, and the fineness of the ground slurry is below 80 μm.

The stirring speed in the step 2) and the step 3) is 300r/min, and the stirring time is 1h and 20min respectively.

The modified airgel in the step 3) is prepared by the following method:

Step 1. Add 0.1-1 part of surfactant to 70-90 parts of water, and stir to obtain a mixed solution;

Step 2, adding 10-30 parts of methyl-containing hydrophobic modifier-modified silica airgel to the above mixed solution while stirring, and stirring at a high speed to obtain an airgel dispersion;

Step 3: Spray-dry the airgel dispersion to prepare the modified airgel.

Compared with the prior art, the present invention introduces a resin with composite functions containing multiple groups, and then prepares coatings with some lightweight heat-insulating fillers and added treated aerogels. The beneficial effects are:

(1) Resins containing various groups such as epoxy groups and phenyl groups are used to overcome the problem of insufficient high temperature resistance of coatings, and the prepared coatings have better high temperature resistance, adhesion and heat insulation properties ;

(2) A kind of resin is used, which overcomes the problem that the coating is difficult to disperse during use due to uneven mixing of various resins, shortens the production cycle, improves the efficiency of preparation, and prepares uniform performance of the coating at the same time. Extend the service life of the coating;

(3) The airgel is pretreated and modified with methyl hydrophobicity, which improves the compatibility of the airgel and the coating system, and fills the airgel pores with pressure-resistant hollow nano-microspheres, which increases the airgel's Weight, the airgel can be easily dispersed in the system, reducing the dispersion time, making the prepared coating uniform in performance and short in cycle;

(4) Filling airgel pores with pressure-resistant silica hollow nanospheres with relatively small thermal conductivity can support the airgel pores, improving the mechanical strength of the airgel and improving air condensation The problem of the collapse of glue holes overcomes the problem that the airgel heat insulation performance is difficult to exert due to the large damage of the airgel structure, so that the prepared coating still has heat insulation effect at a high temperature of 450 °C.

Detailed ways

The present invention will be described in detail below in conjunction with specific embodiments. The following examples will help those skilled in the art to further understand the present invention, but do not limit the present invention in any form. It should be noted that those skilled in the art can make several modifications and improvements without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

It should be noted that, in the case of no conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other, and the parts added of all components are parts by mass unless otherwise specified.

The present invention will be further described below in conjunction with specific examples, but not as a limitation of the present invention.

Example 1

(1) Preparation of airgel composite thermal insulation powder:

1) adding tetraethyl orthosilicate, water, ethanol and hydrochloric acid at a molar ratio of 1:4:14: ^10-4 for hydrolysis to obtain tetraethyl orthosilicate hydrolyzate;

2) Rapidly stirring and adding an alkali solution to the obtained mixed solution to adjust the pH of the system to 5, then adding pressure-resistant silica hollow nanospheres into the mixed solution, and solidifying to obtain a composite gel;

3) breaking the solidified composite gel into small particles, and then placing it in an ethanol solvent for solvent replacement, repeating 4 times;

4) Place the composite gel after solvent replacement in an epoxy silane coupling agent that is 4 times the mass of the composite gel for modification for 48 hours;

5) The liquid is separated, and then the composite gel is graded and dried under nitrogen hot air to prepare an airgel composite heat-insulating powder (80 parts of airgel, 25 parts of pressure-resistant silica hollow nanospheres).

(2) Preparation of modified airgel:

Step 1. Add 0.5 parts of surfactant to 70 parts of water, and stir to obtain mixed solution A1;

Step 2. Add 20 parts of methyl-containing hydrophobic modifier-modified silica airgel to the mixed solution A1 while stirring, and stir at a high speed to obtain an airgel dispersion;

Step 3: Spray-dry the airgel dispersion to prepare the modified airgel.

(3) An epoxy-modified methylphenyl silicone airgel heat-insulating coating is coated on a 15cm*7cm*0.5cm steel plate substrate, and the preparation method comprises the following steps:

1) Add 36 parts of epoxy-modified methylphenyl silicone resin, 6 parts of amino resin, 2 parts of dispersant, and 20 parts of airgel composite heat-insulating powder to 10 parts of water in sequence, grind at 3000r/min for 3 hours at high speed, Control the fineness of the grinding slurry below 80μm;

2) Add 10 parts of glass microspheres, 1 part of defoamer, 1 part of leveling agent, and 2 parts of silane coupling agent to the grinding slurry obtained in 1) in sequence, stir at 300 r/min for 1 hour, and mix well.

3) Add 10 parts of modified airgel, 1 part of antifreeze agent, 0.5 part of water retaining agent, and 0.5 part of antibacterial agent to the homogeneously mixed liquid in 2), and stir at 300r/min for 20min to prepare a sample.

Example 2

(1) Preparation of airgel composite thermal insulation powder:

1) adding tetraethyl orthosilicate, water, ethanol and hydrochloric acid at a molar ratio of 1:4:14: ^10-4 for hydrolysis to obtain tetraethyl orthosilicate hydrolyzate;

2) Add alkali solution to the obtained mixed solution with rapid stirring to adjust the pH of the system to 5, then add 20 parts of pressure-resistant silica hollow nanospheres into the mixed solution, and solidify to obtain a composite gel;

3) breaking the solidified composite gel into small particles, and then placing it in an ethanol solvent for solvent replacement, repeating 4 times;

4) Place the composite gel after solvent replacement in an epoxy silane coupling agent that is 4 times the mass of the composite gel for modification for 48 hours;

5) The liquid is separated, and then the composite gel is graded and dried under nitrogen hot air to prepare an airgel composite heat-insulating powder (80 parts of airgel, 25 parts of pressure-resistant silica hollow nanospheres).

(2) Preparation of modified airgel:

Step 1. Add 0.5 parts of surfactant to 70 parts of water, and stir to obtain mixed solution A1;

Step 2. Add 20 parts of methyl-containing hydrophobic modifier-modified silica airgel to the mixed solution A1 while stirring, and stir at a high speed to obtain an airgel dispersion;

Step 3: Spray-dry the airgel dispersion to prepare the modified airgel.

(3) An epoxy-modified methylphenyl silicone airgel heat-insulating coating is coated on a 15cm*7cm*0.5cm steel plate substrate, and the preparation method comprises the following steps:

1) Add 58 parts of epoxy-modified methylphenyl silicone resin, 2 parts of amino resin, 1 part of dispersant, and 5 parts of airgel composite heat-insulating powder to 10 parts of water in sequence, grind at 3000r/min for 3 hours, Control the fineness of the grinding slurry below 80 μm;

2) Add 10 parts of glass beads, 1 part of defoamer, 1 part of leveling agent, and 3 parts of silane coupling agent to the grinding slurry obtained in 1) in sequence, stir at 300 r/min for 1 hour, and mix well;

3) Add 7 parts of modified airgel, 1 part of antifreeze agent, 0.5 part of water retaining agent, and 0.5 part of antibacterial agent to the homogeneously mixed liquid in 2), and stir at 300r/min for 20min to prepare a sample.

Example 3

(1) Preparation of airgel composite thermal insulation powder:

1) adding tetraethyl orthosilicate, water, ethanol and hydrochloric acid at a molar ratio of 1:4:14: ^10-4 for hydrolysis to obtain tetraethyl orthosilicate hydrolyzate;

2) Add alkali solution to the obtained mixed solution with rapid stirring to adjust the pH of the system to 5, then add 20 parts of pressure-resistant silica hollow nanospheres into the mixed solution, and solidify to obtain a composite gel;

3) breaking the cured composite gel into small particles, and then placing it in an ethanol solvent for solvent replacement, repeating 4 times;

4) Place the composite gel after solvent replacement in an epoxy silane coupling agent that is 4 times the mass of the composite gel for modification for 48 hours;

5) The liquid is separated, and then the composite gel is graded and dried under nitrogen hot air to prepare an airgel composite heat-insulating powder (80 parts of airgel, 25 parts of pressure-resistant silica hollow nanospheres).

(2) Preparation of modified airgel:

Step 1. Add 0.5 parts of surfactant to 90 parts of water, and stir to obtain mixed solution A1;

Step 2. Add 20 parts of methyl-containing hydrophobic modifier-modified silica airgel to the mixed solution A1 while stirring, and stir at a high speed to obtain an airgel dispersion;

Step 3: Spray-dry the airgel dispersion to prepare the modified airgel.

(3) An epoxy-modified methylphenyl silicone airgel heat-insulating coating is coated on a 15cm*7cm*0.5cm steel plate substrate, and the preparation method comprises the following steps:

1) Add 58 parts of epoxy-modified methylphenyl silicone resin, 2 parts of amino resin, 1 part of dispersant, and 5 parts of airgel composite heat-insulating powder to 10 parts of water in sequence, grind at 3000r/min for 3 hours, Control the fineness of the grinding slurry below 80 μm;

2) Add 10 parts of glass beads, 1 part of defoamer, 1 part of leveling agent, and 3 parts of silane coupling agent to the grinding slurry obtained in 1) in sequence, stir at 300 r/min for 1 hour, and mix well;

3) Add 7 parts of modified airgel, 1 part of antifreeze agent, 0.5 part of water retaining agent, and 0.5 part of antibacterial agent to the homogeneously mixed liquid in 2), and stir at 300r/min for 20min to prepare a sample.

Example 4

(1) Preparation of airgel composite thermal insulation powder:

1) adding tetraethyl orthosilicate, water, ethanol and hydrochloric acid at a molar ratio of 1:4:14: ^10-4 for hydrolysis to obtain tetraethyl orthosilicate hydrolyzate;

2) Add alkali solution to the obtained mixed solution with rapid stirring to adjust the pH of the system to 5, then add 20 parts of pressure-resistant silica hollow nanospheres into the mixed solution, and solidify to obtain a composite gel;

3) breaking the solidified composite gel into small particles, and then placing it in an ethanol solvent for solvent replacement, repeating 4 times;

4) Place the composite gel after solvent replacement in an epoxy silane coupling agent that is 4 times the mass of the composite gel for modification for 48 hours;

5) The liquid is separated, and then the composite gel is graded and dried under nitrogen hot air to prepare an airgel composite heat-insulating powder (60 parts of airgel, 15 parts of pressure-resistant silica hollow nanospheres).

(2) Preparation of modified airgel:

Step 1. Add 0.5 parts of surfactant to 90 parts of water, and stir to obtain mixed solution A1;

Step 2. Add 20 parts of methyl-containing hydrophobic modifier-modified silica airgel to the mixed solution A1 while stirring, and stir at a high speed to obtain an airgel dispersion;

Step 3: Spray-dry the airgel dispersion to prepare the modified airgel.

(3) An epoxy-modified methylphenyl silicone airgel heat-insulating coating is coated on a 15cm*7cm*0.5cm steel plate substrate, and the preparation method comprises the following steps:

1) Add 58 parts of epoxy-modified methylphenyl silicone resin, 2 parts of amino resin, 1 part of dispersant, and 5 parts of airgel composite heat-insulating powder to 10 parts of water in sequence, grind at 3000r/min for 3 hours, Control the fineness of the grinding slurry below 80 μm;

2) Add 10 parts of glass beads, 1 part of defoamer, 1 part of leveling agent, and 3 parts of silane coupling agent to the grinding slurry obtained in 1) in sequence, stir at 300 r/min for 1 hour, and mix well;

3) Add 7 parts of modified airgel, 1 part of antifreeze agent, 0.5 part of water retaining agent, and 0.5 part of antibacterial agent to the homogeneously mixed liquid in 2), and stir at 300r/min for 20min to prepare a sample.

Comparative example 1

(1) Preparation of airgel composite thermal insulation powder:

1) adding tetraethyl orthosilicate, water, ethanol and hydrochloric acid at a molar ratio of 1:4:14: ^10-4 for hydrolysis to obtain tetraethyl orthosilicate hydrolyzate;

2) Add alkali solution to the obtained mixed solution with rapid stirring to adjust the pH of the system to 5, then add 20 parts of pressure-resistant silica hollow nanospheres into the mixed solution, and solidify to obtain a composite gel;

3) breaking the cured composite gel into small particles, and then placing it in an ethanol solvent for solvent replacement, repeating 4 times;

4) Place the composite gel after solvent replacement in an epoxy silane coupling agent that is 4 times the mass of the composite gel for modification for 48 hours;

5) The liquid is separated, and then the composite gel is graded and dried under nitrogen hot air to prepare the airgel composite thermal insulation powder.

(2) A kind of pure organosilicon airgel thermal insulation coating is coated on 15cm*7cm*0.5cm steel plate base material, and preparation method comprises the following steps:

1) To 10 parts of water, add 12 parts of pure silicone resin, 6 parts of amino resin, 12 parts of epoxy resin, 12 parts of phenyl-containing resin, 2 parts of dispersant, and 20 parts of airgel composite thermal insulation powder, 3000r/min high-speed grinding for 3 hours (the resin is not mixed evenly), and the fineness of the grinding slurry is controlled below 80μm;

2) Add 10 parts of glass microspheres, 1 part of defoamer, 1 part of leveling agent, and 2 parts of silane coupling agent to the grinding slurry obtained in 1) in sequence, stir at 300 r/min for 1 hour, and mix well.

3) Add 10 parts of modified airgel, 1 part of antifreeze agent, 0.5 part of water retaining agent, and 0.5 part of antibacterial agent to the homogeneously mixed liquid in 2), and stir at 300r/min for 20min to prepare a sample.

Comparative example 2

A mixed resin airgel thermal insulation coating is coated on a 15cm*7cm*0.5cm steel plate substrate, and the preparation method comprises the following steps:

1) Add 58 parts of epoxy-modified methylphenyl silicone resin, 2 parts of amino resin, and 1 part of dispersant to 10 parts of water in sequence, grind at a high speed of 3000r/min for 3 hours, and control the fineness of the grinding slurry below 80 μm;

2) Add 10 parts of glass beads, 1 part of defoamer, 1 part of leveling agent, and 3 parts of silane coupling agent to the grinding slurry obtained in 1) in sequence, stir at 300 r/min for 1 hour, and mix well;

3) Add 12 parts of airgel, 1 part of antifreeze, 0.5 part of water retaining agent, and 0.5 part of antibacterial agent to the homogeneously mixed liquid in 2), and stir at 300r/min for 20min to prepare a sample.

The sample performance test provided in the embodiment of the present invention and comparative example 1-2 is shown in the following table:

It can be seen from the above table that the epoxy-modified methylphenyl silicone airgel heat-insulating coating provided by the present invention has better performances of high temperature resistance, adhesion, heat insulation, and thermal shock resistance.

Claims (8)

1. An epoxy-modified methylphenyl silicone airgel heat-insulating coating is characterized in that it is mainly made of the following raw materials: 20-58 parts of epoxy-modified methylphenyl silicone resin, amino resin 2-6 parts, 5-20 parts of airgel composite thermal insulation powder, 2-10 parts of modified airgel, 1-10 parts of hollow glass microspheres, 1-5 parts of mica powder, 10-20 parts of water, 0.1-1 part of dispersant, 0.1-1 part of defoamer, 0.1-1 part of leveling agent, 1-3 parts of silane coupling agent, 0.1-2 parts of antifreeze, 0.1-0.5 part of water retaining agent and 0.1-1 part of antibacterial agent 0.5 part; the inner layer structure of the airgel composite thermal insulation powder is that airgel holes are filled with pressure-resistant silicon dioxide hollow nano-microspheres. 2. a kind of epoxy-modified methylphenyl organosilicon airgel thermal insulation coating as claimed in claim 1, is characterized in that, the airgel in the described airgel composite thermal insulation powder is containing Silica airgel modified by methyl hydrophobic modifier. 3. A kind of epoxy-modified methylphenyl organosilicon airgel thermal insulation coating as claimed in claim 1, is characterized in that, described airgel composite thermal insulation powder comprises the following components by mass parts : 60-80 parts of airgel and 15-25 parts of pressure-resistant silica hollow nanospheres. 4. A preparation method for epoxy-modified methylphenyl organosilicon airgel heat-insulating coating, is characterized in that, comprises the following steps: 1) Weighing epoxy-modified methylphenyl silicone resin, amino resin, dispersant, and airgel composite heat-insulating powder, adding them to water in sequence, and grinding to obtain a grinding slurry; 2) Add glass microspheres, defoamer, leveling agent, silane coupling agent successively to the grinding slurry obtained in 1), and stir and mix evenly; 3) Add modified airgel, antifreeze agent, water retaining agent, and antifungal agent to the uniformly mixed liquid in 2) and stir to prepare epoxy modified methylphenyl silicone airgel thermal insulation coating . 5. the preparation method of organosilicon airgel thermal insulation coating as claimed in claim 4, is characterized in that, the preparation method of the airgel composite thermal insulation powder in described step 1) comprises the following steps: (1) Add tetraethyl orthosilicate, water, ethanol and hydrochloric acid to carry out hydrolysis, obtain tetraethyl orthosilicate hydrolyzate; (2) Rapidly stirring and adding an alkali solution to the obtained mixed solution to adjust the pH of the system, then adding pressure-resistant silica hollow nanospheres into the mixed solution, and solidifying to obtain a composite gel; (3) breaking the cured composite gel into small particles, and then placing it in an ethanol solvent for solvent replacement; (4) Place the composite gel after solvent replacement in a methyl-containing hydrophobic modifier for modification; (5) The liquid is separated, and then the composite gel is dried to prepare the airgel composite thermal insulation powder. 6. The preparation method of silicone airgel thermal insulation coating as claimed in claim 4, characterized in that, in said step 1), the grinding speed is 3000r/min, and the fineness of the ground slurry is below 80 μm. 7. the preparation method of organosilicon airgel thermal insulation coating as claimed in claim 4, is characterized in that, described step 2) and step 3) in the stirring velocity is 300r/min, and stirring time is respectively 1h and 20min. 8. the preparation method of organosilicon airgel thermal insulation coating as claimed in claim 4, is characterized in that, the preparation method of the modified airgel in described step 3) comprises the following steps: Step 1. Add 0.1-1 part of surfactant to 70-90 parts of water, and stir to obtain mixed solution A1; Step 2. Add 10-30 parts of methyl-containing hydrophobic modifier-modified silica airgel to the mixed solution A1 while stirring, and stir at a high speed to obtain an airgel dispersion; Step 3: Spray-dry the airgel dispersion to prepare the modified airgel.