Long-time ultraviolet radiation resistant white thermal control coating and preparation method thereof

Abstract

The invention relates to a long-time ultraviolet radiation resistant white thermal control coating and a preparation method thereof, and belongs to the technical field of thermal control coatings, the coating comprises the following raw materials: 1.5-2 parts of a white pigment, 1 part of ultraviolet radiation resistant silicon-based resin, the methyl ethyl phenyl silicone resin is prepared by taking diethyldiethoxysilane, methyltrimethoxysilane, dimethyldimethoxysilane, methylphenyl dimethoxysilane and tetraethyl orthosilicate as reaction raw materials and carrying out hydrolytic condensation under the catalysis of a hydrochloric acid catalyst; through reasonable formula design, the molecular weight and molecular weight distribution of linear polysiloxane are designed and optimized, and meanwhile, a special ethyl functional group is introduced, so that the silicon-based resin has excellent low-temperature and room-temperature toughness; by designing and optimizing the types and proportions of the T and Q type alkoxy silane in the synthetic raw materials, the silicon-based resin has excellent long-time ultraviolet radiation resistance, and the white thermal control coating is flat and compact in paint film and good in thermal control performance.

Description

Technical Field

[0001] The invention relates to a white thermal control coating resistant to long-time ultraviolet radiation and a preparation method thereof, belonging to the technical field of thermal control coatings. Background Art

[0002] At present, deep space probes are developing in the direction of lightweight and long-duration, and ultra-low-density materials are the first choice for thermal protection structures. Existing thermal control coatings are mostly silicone rubber resin matrices, which will crystallize and lose toughness in low-temperature environments. When applied to the surface of rough and porous ultra-low-density thermal protection substrates, they will crack due to mechanical and thermal mismatch, affecting the performance of the coating and thermal protection structure. In addition, as the service time increases, the space environment faced by the coating becomes more severe, especially long-term far and near ultraviolet radiation, which places higher requirements on the spatial stability of the coating. Summary of the invention

[0003] The technical problem solved by the present invention is: through the synthesis research of ultraviolet radiation-resistant silicone-based resin for space use, a space-grade silicone-based resin resistant to long-term ultraviolet radiation is prepared, which is used to replace the existing silicone rubber resin matrix, and a thermal control coating is prepared based on this, so as to achieve a balance between the low-temperature toughness and long-term ultraviolet resistance of the current thermal control coating.

[0004] The technical solution of the present invention is as follows:

[0005] A white thermal control coating resistant to long-term ultraviolet radiation, the raw materials of the coating comprising the following components in parts by mass:

[0006] 1.5-2 parts of white pigment;

[0007] 1 part of UV-resistant silicone resin;

[0008] The ultraviolet radiation resistant silicon-based resin is methylethylphenyl silicone resin, which is prepared by hydrolysis condensation under the catalysis of hydrochloric acid catalyst using diethyldiethoxysilane, methyltrimethoxysilane, dimethyldimethoxysilane, methylphenyldimethoxysilane and tetraethyl orthosilicate as reaction raw materials.

[0009] In the above-mentioned white thermal control coating resistant to long-term ultraviolet radiation, the white pigment is one of zinc oxide, titanium dioxide or zinc titanate powder.

[0010] In the above-mentioned white thermal control coating resistant to long-term ultraviolet radiation, the molecular weight of the methyl ethyl phenyl silicone resin is 1000-2000.

[0011] In the above long-term UV radiation resistant white thermal control coating, the UV radiation resistant silicone-based resin satisfies: the elongation at break at -80°C is greater than 100%, and the tensile strength at -80°C is greater than 1.0 MPa.

[0012] In the above-mentioned long-term ultraviolet radiation resistant white thermal control coating, the preparation method of the methyl ethyl phenyl silicone resin comprises:

[0013] (1) dropping a hydrochloric acid solution into a reaction kettle containing a mixed solution of diethyldiethoxysilane, methyltrimethoxysilane, dimethyldimethoxysilane, methylphenyldimethoxysilane and tetraethyl orthosilicate, and heating the mixture to perform a hydrolysis reaction; wherein the molar ratio of diethyldiethoxysilane, methyltrimethoxysilane, dimethyldimethoxysilane, methylphenyldimethoxysilane and tetraethyl orthosilicate is 1-2:1-2:2-3:1-2:1-2;

[0014] (2) transferring the product of the hydrolysis reaction to a new reactor and continuing to increase the temperature of the reaction system to carry out a condensation reaction;

[0015] (3) The product of the condensation reaction is subjected to reduced pressure distillation to separate the reaction product to obtain methyl ethyl phenyl silicone resin.

[0016] In the above-mentioned long-term ultraviolet radiation resistant white thermal control coating, the dripping speed of the hydrochloric acid solution in step (1) is 10-15 ml / min; the temperature of the hydrolysis reaction is 100-110° C., and the reaction time is 8-10 h; the concentration of the hydrochloric acid solution is 1000-2000 ppm.

[0017] In the above-mentioned long-term ultraviolet radiation resistant white thermal control coating, the temperature of the condensation reaction in step (2) is 150-170° C., and the reaction time is 6-8 hours.

[0018] In the above-mentioned white thermal control coating resistant to long-term ultraviolet radiation, the temperature of the reduced pressure distillation in step (3) is 180-200° C., the vacuum pressure is 0.05-0.08 MPa, and the distillation time is 2-5 hours.

[0019] The method for preparing the above-mentioned white thermal control coating resistant to long-term ultraviolet radiation comprises:

[0020] (1) uniformly mixing the white filler and the organic solution of the ultraviolet radiation resistant silicone-based resin to obtain a mixed solution;

[0021] (2) grinding and dispersing the mixed solution obtained in step (1) to a fineness of less than 60 μm by ball milling to obtain a thermal control coating;

[0022] (3) After the thermal control coating obtained in step (2) is stirred evenly, it is coated on the substrate that has been surface treated in advance, with each coat being separated by more than 15 minutes to obtain a white thermal control coating suitable for long-term ultraviolet irradiation.

[0023] In the above-mentioned method for preparing a white thermal control coating resistant to long-term ultraviolet radiation, the organic solution of the ultraviolet radiation-resistant silicon-based resin in step (1) is butyl acetate, ethyl acetate or xylene; the mass ratio of the ultraviolet radiation-resistant silicon-based resin to the organic solvent is 1:2-3; and the ball milling time in step (2) is 3-6 hours.

[0024] In the above-mentioned method for preparing the long-term ultraviolet radiation resistant white thermal control coating, the substrate in step (3) is a phenolic low-density heat-resistant substrate with a density of 0.30 to 0.8 g / cm 3 .

[0025] In the above-mentioned method for preparing the white thermal control coating resistant to long-term ultraviolet radiation, the coating method in step (3) includes brushing, scraping, spraying or roller coating.

[0026] Compared with the prior art, the present invention has at least the following beneficial effects:

[0027] (1) The embodiments of the present invention optimize the molecular weight and molecular weight distribution of linear polysiloxane by design, and introduce special ethyl functional groups at the same time, so that the silicone-based resin has excellent low-temperature and room-temperature toughness; optimize the types and proportions of T and Q alkoxysilanes in the synthetic raw materials by design, so that the silicone-based resin has excellent resistance to long-term ultraviolet radiation. By designing a reasonable reaction process, a silicone-based resin with a special structure is finally prepared, which takes into account both flexibility and resistance to long-term ultraviolet radiation.

[0028] (2) The embodiment of the present invention adopts reasonable formula design to prepare a white thermal control coating suitable for long-term ultraviolet radiation. The paint film is smooth and dense, and the thermal control performance is good. The problem of poor appearance after coating on the surface of phenolic-based low-density materials and serious degradation of absorption ratio in space ultraviolet radiation environment is solved.

[0029] (3) The long-term ultraviolet radiation resistant white thermal control coating system provided in the embodiment of the present invention is composed of a silicon-based resin and an inorganic white oxide filler. The preparation process is simple and can be cured at room temperature. After the thermal control coating based on the long-term ultraviolet radiation resistant silicon-based resin is subjected to 100 thermal cycles (-196°C to 150°C) on the surface of an ultra-low density substrate, there is no blistering, cracking, or peeling on the appearance of the thermal control coating, and it has good mechanical and thermal matching with the ultra-phenolic low-density substrate. In addition, after the coating is subjected to 5000ESH ultraviolet radiation, the change in solar absorption ratio is ≤0.2.

[0030] (4) The thermal control coating system provided by the embodiment of the present invention which takes into account both low temperature toughness and resistance to space ultraviolet radiation uses inorganic white oxide filler and special silicon-based resin as main raw materials, and through reasonable formula design, the solar absorption ratio (α s ) is less than 0.18, hemispherical emissivity (ε H) is greater than 0.85. After 100 thermal cycles (-196℃~150℃) on the surface of phenolic low-density substrate, the thermal control coating has no blistering, cracking or peeling. After 5000ESH ultraviolet irradiation, the change in solar absorption ratio is ≤0.2, which solves the problems of mechanical and thermal mismatch between the existing thermal control coating and the low-density carbon phenolic substrate and yellowing of the coating due to long-term ultraviolet irradiation. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is the NMR silicon spectrum of the methyl ethyl phenyl silicone resin prepared in Example 1 of the present invention;

[0032] Figure 2 This is a gel permeation chromatogram of the methylethylphenyl silicone resin prepared in Example 1 of the present invention;

[0033] Figure 3 This is the infrared spectrum of the methylethylphenyl silicone resin prepared in Example 1 of the present invention. DETAILED DESCRIPTION

[0034] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments:

[0035] The present invention provides a white thermal control coating resistant to long-term ultraviolet radiation, wherein the raw materials of the coating include the following components in parts by mass:

[0036] 1.5-2 parts of white pigment;

[0037] 1 part of UV-resistant silicone resin;

[0038] In an optional embodiment, the white pigment is one of zinc oxide, titanium dioxide or zinc titanate powder.

[0039] In an optional embodiment, the ultraviolet radiation resistant silicone-based resin is methylethylphenyl silicone resin, which is a silicone resin with excellent performance and resistance to long-term ultraviolet radiation; the methylethylphenyl silicone resin is prepared by a hydrolysis condensation method using diethyldiethoxysilane, methyltrimethoxysilane, dimethyldimethoxysilane, methylphenyldimethoxysilane, and tetraethyl orthosilicate as reaction raw materials under the catalysis of hydrochloric acid catalyst.

[0040] In an optional embodiment, the ultraviolet radiation resistant silicone-based resin meets the following requirements: the elongation at break at -80°C is greater than 100%; and the tensile strength at -80°C is greater than 1.0 MPa.

[0041] In an optional embodiment, the molecular weight of the methylethylphenyl silicone resin in the methylethylphenyl silicone resin is 1000-2000.

[0042] The method for preparing the ultraviolet radiation resistant silicone-based resin in the embodiment of the present invention comprises the following steps:

[0043] (1) dropping a hydrochloric acid solution into a reaction kettle containing a mixed solution of diethyldiethoxysilane, methyltrimethoxysilane, dimethyldimethoxysilane, methylphenyldimethoxysilane and tetraethyl orthosilicate, and heating the mixture to perform a hydrolysis reaction;

[0044] In an optional embodiment, the molar ratio of diethyldiethoxysilane, methyltrimethoxysilane, dimethyldimethoxysilane, methylphenyldimethoxysilane and tetraethyl orthosilicate is 1-2:1-2:2-3:1-2:1-2; the dropping speed of the dropping funnel is 10-15 ml / min; the temperature of the hydrolysis reaction is 100-110°C, and the reaction time is 8-10h; the concentration of the hydrochloric acid solution is 1000-2000ppm.

[0045] (2) The synthesized product in step (1) is transferred to a new reaction device, and the temperature of the reaction system is continued to be increased to carry out a condensation reaction.

[0046] In an optional embodiment, the condensation reaction temperature is 150-170° C., and the reaction time is 6-8 hours.

[0047] (3) subjecting the synthetic product in step (2) to a reduced pressure distillation operation to separate the reaction product to obtain a methyl ethyl phenyl silicone resin.

[0048] In an optional embodiment, the temperature of the reduced pressure distillation is 180-200° C., the vacuum pressure is 0.05-0.08 MPa, and the distillation time is 2-5 h.

[0049] The synthetic route of methyl ethyl phenyl silicone resin is shown below:

[0050]

[0051] The embodiment of the present invention provides a method for preparing a white thermal control coating resistant to long-term ultraviolet radiation, the method comprising the following steps:

[0052] (1) The white filler is uniformly mixed with the organic solution of the ultraviolet radiation resistant silicone-based resin to prepare a white mixed solution; in an optional embodiment, the organic solution of the ultraviolet radiation resistant silicone-based resin is butyl acetate, ethyl acetate or xylene; wherein the mass ratio of the ultraviolet radiation resistant silicone-based resin to the organic solvent is 1:2-3.

[0053] (2) The mixed solution obtained in step (1) is ground and dispersed by ball milling to a fineness of less than 60 μm to prepare a white thermal control coating; in an optional embodiment, the ball milling time is 3 to 6 hours.

[0054] (3) After the thermal control coating obtained in step (2) is stirred evenly, it is coated on a substrate that has been pre-surface treated, and each spraying is separated by more than 15 minutes to obtain a white thermal control coating suitable for long-term ultraviolet radiation. In an optional embodiment, the substrate is a phenolic low-density heat-resistant substrate with a density of 0.30 to 0.8 g / cm 3 The coating methods include brushing, scraping, spraying or rolling.

[0055] In the embodiment of the present invention, the thermal control coating with a long-term ultraviolet radiation-resistant silicone-based resin as the matrix is ​​subjected to 100 thermal cycles (-196°C to 150°C) on the surface of an ultra-low-density substrate. The thermal control coating has no blistering, cracking, or peeling on the surface, and has good mechanical and thermal matching with the ultra-phenolic low-density substrate. In addition, after the coating is subjected to 5000ESH ultraviolet radiation, the change in solar absorption ratio is ≤0.2. The solar absorption ratio (α s ) is less than 0.18, hemispherical emissivity (ε H ) is greater than 0.85. After 100 thermal cycles (-196℃~150℃) on the surface of phenolic low-density substrate, the thermal control coating has no blistering, cracking or peeling. After 5000ESH ultraviolet irradiation, the change in solar absorption ratio is ≤0.2.

[0056] Example 1

[0057] Diethyldiethoxysilane, methyltrimethoxysilane, dimethyldimethoxysilane, methylphenyldimethoxysilane and tetraethyl orthosilicate are mixed uniformly in a molar ratio of 2:1:2:1:2, and a diluted hydrochloric acid solution is dripped into the mixture at a uniform rate of 10 ml / min through a dropping funnel. The temperature is raised for hydrolysis reaction. The reaction temperature is 100°C and the reaction time is 8 hours. The synthesized product is transferred to a new reaction unit, and the temperature of the reaction system is continued to be raised for condensation. The reaction temperature is 150°C and the reaction time is 6 hours. The condensation product is then subjected to a reduced pressure distillation operation to separate the reaction product. The distillation temperature is 180°C and the vacuum pressure is 0.08 MPa; the distillation time is 2 hours, and a UV-resistant silicone-based resin is obtained. Figure 1 The figure shows the NMR spectrum of the methylethylphenyl silicone resin prepared in Example 1; Figure 2 This is the gel permeation chromatogram of the methylethylphenyl silicone resin prepared in Example 1; Figure 3 This is the infrared spectrum of the methylethylphenyl silicone resin prepared in Example 1.

[0058] The ZnO filler with a mass ratio of 1.5:1 is uniformly mixed with an organic solution of a UV-resistant silicone-based resin to prepare a white mixed solution; the white mixed solution is ground and dispersed to a fineness of less than 60 μm by a ball milling process to obtain a white thermal control coating.

[0059] After the obtained thermal control coating is stirred evenly, it is sprayed on the substrate that has been pre-surface treated, and each spraying is separated by more than 10 minutes to obtain a low-temperature tough thermal control coating suitable for the surface of ultra-low density materials. The thermal control coating is prepared by drying and curing at room temperature for more than 72 hours, and the basic performance is measured. The results are shown in Table 1.

[0060] Table 1 Thermal control coating properties

[0061]

[0062]

[0063] Example 2

[0064] Diethyldiethoxysilane, methyltrimethoxysilane, dimethyldimethoxysilane, methylphenyldimethoxysilane and tetraethyl orthosilicate were mixed uniformly in a molar ratio of 1:1:3:1:1, and the hydrochloric acid diluent was dripped into the mixed solution at a uniform speed of 10 ml / min through a dropping funnel, and the temperature was raised for hydrolysis reaction, the reaction temperature was 100°C, and the reaction time was 8 hours. The synthesized product was transferred to a new reaction device, and the temperature of the reaction system was continued to be raised for condensation, the reaction temperature was 150°C, and the reaction time was 6 hours. The condensation product was then subjected to a reduced pressure distillation operation to separate the reaction product, the distillation temperature was 180°C, the vacuum pressure was 0.08 MPa; the distillation time was 2 hours, and the ultraviolet radiation-resistant silicone resin was obtained.

[0065] The ZnO filler with a mass ratio of 1.5:1 is uniformly mixed with an organic solution of a UV-resistant silicone-based resin to prepare a white mixed solution; the white mixed solution is ground and dispersed to a fineness of less than 60 μm by a ball milling process to obtain a white thermal control coating.

[0066] After the obtained thermal control coating is stirred evenly, it is sprayed on the substrate that has been pre-treated, and each spraying is separated by more than 10 minutes to obtain a low-temperature tough thermal control coating suitable for the surface of ultra-low density materials. The thermal control coating is prepared by drying and curing at room temperature for more than 72 hours, and the basic performance is measured. The results are shown in Table 2.

[0067] Table 2 Thermal control coating properties

[0068]

[0069]

[0070] Example 3

[0071] Diethyldiethoxysilane, methyltrimethoxysilane, dimethyldimethoxysilane, methylphenyldimethoxysilane and tetraethyl orthosilicate are mixed uniformly in a molar ratio of 2:1:3:1:1, and a hydrochloric acid diluent is dripped into the mixture at a uniform speed of 10 ml / min through a dropping funnel, and the temperature is raised for hydrolysis reaction, the reaction temperature is 100°C, and the reaction time is 8 hours. The synthesized product is transferred to a new reaction device, and the temperature of the reaction system is continued to be raised for condensation, the reaction temperature is 150-180°C, and the reaction time is 6-8 hours. The condensation product is then subjected to a reduced pressure distillation operation to separate the reaction product, the distillation temperature is 180°C, the vacuum pressure is 0.08 MPa; the distillation time is 2 hours, and a UV-resistant silicone resin is obtained.

[0072] The ZnO filler with a mass ratio of 1.5:1 is uniformly mixed with an organic solution of a UV-resistant silicone-based resin to prepare a white mixed solution; the white mixed solution is ground and dispersed to a fineness of less than 60 μm by a ball milling process to obtain a white thermal control coating.

[0073] After the obtained thermal control coating is stirred evenly, it is sprayed on the substrate that has been pre-treated, and each spraying is separated by more than 10 minutes to obtain a low-temperature tough thermal control coating suitable for the surface of ultra-low density materials. The thermal control coating is prepared by drying and curing at room temperature for more than 72 hours, and the basic performance is measured. The results are shown in Table 3.

[0074] Table 3 Thermal control coating properties

[0075] Paint film drying time ＜48h <![CDATA[Solar absorptance α s > 0.18 <![CDATA[Infrared emissivity ε H > 0.87 Coating status after 100 thermal cycles No blistering, cracking or peeling Absorption ratio change after 5000ESH 0.22

[0076] Example 4

[0077] Diethyldiethoxysilane, methyltrimethoxysilane, dimethyldimethoxysilane, methylphenyldimethoxysilane and tetraethyl orthosilicate are mixed uniformly in a molar ratio of 1:1:2:1:1, and a hydrochloric acid diluent is dripped into the mixture at a uniform speed of 10 ml / min through a dropping funnel, and the temperature is raised for hydrolysis reaction, the reaction temperature is 100°C, and the reaction time is 8 hours. The synthesized product is transferred to a new reaction device, and the temperature of the reaction system is continued to be raised for condensation, the reaction temperature is 150-180°C, and the reaction time is 6-8 hours. The condensation product is then subjected to a reduced pressure distillation operation to separate the reaction product, the distillation temperature is 180°C, the vacuum pressure is 0.08 MPa; the distillation time is 2 hours, and a UV-resistant silicone resin is obtained.

[0078] A zinc titanate filler having a mass ratio of 2:1 is uniformly mixed with an organic solution of an ultraviolet radiation-resistant silicone-based resin to prepare a white mixed solution; the white mixed solution is ground and dispersed to a fineness of less than 60 μm by a ball milling process to obtain a white thermal control coating.

[0079] After the obtained thermal control coating is stirred evenly, it is sprayed on the substrate that has been pre-surface treated, and each spraying is separated by more than 10 minutes to obtain a low-temperature tough thermal control coating suitable for the surface of ultra-low density materials. The thermal control coating is prepared by drying and curing at room temperature for more than 72 hours, and the basic performance is measured. The results are shown in Table 1.

[0080] Table 4 Low temperature toughness thermal control coating properties

[0081] Paint film drying time ＜48h <![CDATA[Solar absorptance α s > 0.18 <![CDATA[Infrared emissivity ε H > 0.87 Coating status after 100 thermal cycles No blistering, cracking or peeling Absorption ratio change after 5000ESH 0.20

[0082] The above description is only the best specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by any technician familiar with the technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

[0083] The contents not described in detail in the specification of the present invention belong to the common knowledge of the professionals in this field.

Claims

1. A white thermal control coating resistant to long-term ultraviolet radiation, characterized in that: The raw materials of the coating include the following components in parts by weight: 1.5-2 parts of white pigment; 1 part of UV-resistant silicone resin; The ultraviolet radiation resistant silicon-based resin is methylethylphenyl silicone resin, which is prepared by hydrolysis condensation under the catalysis of hydrochloric acid catalyst using diethyldiethoxysilane, methyltrimethoxysilane, dimethyldimethoxysilane, methylphenyldimethoxysilane and tetraethyl orthosilicate as reaction raw materials.

2. The long-term ultraviolet radiation resistant white thermal control coating according to claim 1, characterized in that: The white pigment is one of zinc oxide, titanium dioxide or zinc titanate powder.

3. The long-term ultraviolet radiation resistant white thermal control coating according to claim 1, characterized in that: The molecular weight of the methylethylphenyl silicone resin is 1000-2000.

4. The long-term ultraviolet radiation resistant white thermal control coating according to claim 1, characterized in that: The ultraviolet radiation resistant silicone-based resin meets the following requirements: the elongation at break at -80°C is greater than 100%, and the tensile strength at -80°C is greater than 1.0 MPa.

5. The long-term ultraviolet radiation resistant white thermal control coating according to claim 1, characterized in that: The preparation method of the methylethylphenyl silicone resin comprises: (1) dropping a hydrochloric acid solution into a reaction kettle containing a mixed solution of diethyldiethoxysilane, methyltrimethoxysilane, dimethyldimethoxysilane, methylphenyldimethoxysilane and tetraethyl orthosilicate, and heating the mixture to perform a hydrolysis reaction; wherein the molar ratio of diethyldiethoxysilane, methyltrimethoxysilane, dimethyldimethoxysilane, methylphenyldimethoxysilane and tetraethyl orthosilicate is 1-2:1-2:2-3:1-2:1-2; (2) transferring the product of the hydrolysis reaction to a new reactor and continuing to increase the temperature of the reaction system to carry out a condensation reaction; (3) The product of the condensation reaction is subjected to reduced pressure distillation to separate the reaction product to obtain methyl ethyl phenyl silicone resin.

6. The white thermal control coating suitable for long-term ultraviolet radiation according to claim 5, characterized in that: The dripping speed of the hydrochloric acid solution in step (1) is 10-15 ml / min; the temperature of the hydrolysis reaction is 100-110° C., and the reaction time is 8-10 h; the concentration of the hydrochloric acid solution is 1000-2000 ppm.

7. The long-term ultraviolet radiation resistant white thermal control coating according to claim 5, characterized in that: The temperature of the condensation reaction in step (2) is 150-170° C., and the reaction time is 6-8 hours.

8. The long-term ultraviolet radiation resistant white thermal control coating according to claim 5, characterized in that: The temperature of the reduced pressure distillation in step (3) is 180-200° C., the vacuum pressure is 0.05-0.08 MPa, and the distillation time is 2-5 hours.

9. The method for preparing a white thermal control coating resistant to long-term ultraviolet radiation according to any one of claims 1 to 8, characterized in that: include: (1) uniformly mixing the white filler and the organic solution of the ultraviolet radiation resistant silicone-based resin to obtain a mixed solution; (2) grinding and dispersing the mixed solution obtained in step (1) to a fineness of less than 60 μm by ball milling to obtain a thermal control coating; (3) After the thermal control coating obtained in step (2) is stirred evenly, it is coated on the substrate that has been surface treated in advance, with each coat being separated by more than 15 minutes to obtain a white thermal control coating suitable for long-term ultraviolet irradiation.

10. The method for preparing a white thermal control coating resistant to long-term ultraviolet radiation according to claim 9, characterized in that: The organic solution of the ultraviolet radiation resistant silicon-based resin in step (1) is butyl acetate, ethyl acetate or xylene; the mass ratio of the ultraviolet radiation resistant silicon-based resin to the organic solvent is 1:2-3; and the ball milling time in step (2) is 3-6 hours.

11. The method for preparing a white thermal control coating resistant to long-term ultraviolet radiation according to claim 9, characterized in that: The substrate in step (3) is a phenolic low-density heat-resistant substrate with a density of 0.30 to 0.8 g / cm 3 .

12. The method for preparing a white thermal control coating resistant to long-term ultraviolet radiation according to claim 9, characterized in that: The coating method in step (3) includes brushing, scraping, spraying or roller coating.

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