Satellite wave-transparent thermal control film capable of preventing light pollution in space as well as preparation method and application of satellite wave-transparent thermal control film

Abstract

The invention discloses a satellite wave-transparent thermal control film capable of preventing light pollution in space and a preparation method and application thereof.The satellite wave-transparent thermal control film is of a flexible structure composed of a film system functional layer, a nanometer heat dissipation base film layer, a gum layer and a release film layer, and the film system functional layer is a multi-layer film system formed through sputtering or evaporation; the protective layer is a functional layer for preventing light pollution; the nano heat dissipation base film layer is a radiation heat dissipation functional layer and is a nano heat dissipation film formed by processing polyimide or fluororesin and nano filler; the back adhesive layer is made of an organic silicon pressure-sensitive adhesive; and the release film layer is made of a PET release film and is used for protecting the back adhesive layer. Through processing and design of the surface of the film coating, the reflection direction of sunlight is directionally changed, the effects of heat dissipation, wave transmission and space light pollution prevention are achieved, and the film is used for wave transmission, heat dissipation and light pollution protection of batched satellites.

Description

Technical Field

[0001] The present invention belongs to the technical field of satellite thermal control protection, and in particular relates to a satellite wave-transmitting thermal control film for preventing space light pollution, and a preparation method and application thereof. Background Art

[0002] At present, spacecraft in orbit need to withstand the combined effects of various extremely harsh and complex space environmental factors, which make the external heat flow environment of spacecraft constantly change, thus affecting the temperature change of spacecraft. With the development of mass satellite constellations, especially the giant constellations represented by SpaceX's Starlink in the United States, since the surface of satellites is generally white or golden, the satellites will reflect the sunlight shining on the surface of the stars to the ground and be observed by ground detectors. The launch and operation of a large number of low-orbit satellite constellations have brought great interference to ground-based astronomical observations. The British "Nature Astronomy" published a series of articles specifically exploring the impact of artificial satellites and space debris on the brightness of the night sky. The increasing cloud of "space junk" reflects light back to the earth, causing serious concerns in the astronomical community: the potential impact of light pollution and its potential interference with ground-based telescopes and space telescopes.

[0003] In January 2023, Space X reached an agreement with the National Science Foundation of the United States to try to solve the light pollution caused by Starlink satellites, such as painting the satellites black and blocking some solar energy. However, the problem has not yet been solved, and some attempts to solve the problem have been gradually abandoned in actual operation. The light pollution caused by satellites is mainly caused by the reflection of sunlight from stars to the ground. Since the surface coating of satellites is generally diffuse white, it will reflect sunlight in any direction and can be easily observed from the ground. Changing the reflective properties of the surface of the thermal control coating and adjusting the diffuse reflection properties to mirror reflection properties can achieve the purpose of directional reflection of sunlight, which can greatly reduce the sunlight reflected to the ground and reduce light pollution.

[0004] Patent document CN202210203621.4 discloses a method for manufacturing a satellite on-orbit automatic shading thermal control device and a satellite thereof, and proposes an automatically adjustable shading thermal control device, which is installed on both sides of the ground and adjusts the shading angle according to the on-orbit lighting conditions. It can reduce the reflected sunlight from the ground by more than 95%, greatly reducing the impact of light pollution, but requires a special rotating shading device, which brings a large resource overhead to the entire satellite, and the shading device is difficult to cover all areas, and the light pollution protection effect is limited. Patent document CN202011357112.4 discloses a method for preparing a high-absorption and high-emissivity ultra-black molecular adsorption coating. The average solar absorption rate of the coating is 95%, and the hemispherical emissivity is 91%, so that the surface layer has the performance of eliminating stray light, which can meet the application requirements of spacecraft and satellite imaging systems, but the ultra-black coating will cause a significant increase in temperature in the solar-exposed area of ​​the satellite, making it difficult to meet the thermal control requirements of the satellite. Summary of the invention

[0005] In view of the problem of light pollution in low-orbit mass-produced commercial satellite constellations in the prior art, the main purpose of the present invention is to provide a satellite wave-transmitting thermal control film for preventing space light pollution. Through the processing and design of the film coating surface, the reflection direction of sunlight is directionally changed to achieve the effects of heat dissipation, wave transmission and space light pollution prevention.

[0006] Another object of the present invention is to provide a method for preparing the satellite wave-transmitting thermal control film.

[0007] Another object of the present invention is to provide an application of the satellite wave-transmitting thermal control film in the wave transmission, heat dissipation and light pollution protection of mass-produced satellites.

[0008] To achieve the above object, the present invention adopts the following technical solution:

[0009] The first aspect of the present invention provides a satellite wave-transmitting thermal control film for preventing space light pollution, which is a flexible structure composed of a film functional layer, a nano heat dissipation base film layer, a backing layer and a release film layer, wherein:

[0010] The film system functional layer is a multilayer film system formed by sputtering or evaporation, and is a functional layer for preventing light pollution;

[0011] The nano heat dissipation base film layer is a radiation heat dissipation functional layer, which is a nano heat dissipation film made of polyimide or fluororesin and nano fillers;

[0012] The material of the back adhesive layer is silicone pressure-sensitive adhesive;

[0013] The release film layer is made of PET release film, which is used to protect the adhesive layer.

[0014] Preferably, the film functional layer has a thickness of 0.2-2 um and is composed of a high refractive index film layer and a low refractive index film layer.

[0015] More preferably, the high refractive index film is at least one of titanium oxide, tantalum oxide, zirconium oxide, hafnium oxide, and niobium oxide; and / or the low refractive index film is at least one of silicon oxide, aluminum oxide, magnesium fluoride, and aluminum fluoride.

[0016] Preferably, the nano heat dissipation base film layer has a thickness of 50 to 200 um and is formed by melt casting of polyimide or fluororesin and nano filler.

[0017] Preferably, the nanofiller is at least one nanomaterial selected from the group consisting of titanium oxide, zinc oxide, zirconium oxide, aluminum oxide and silicon oxide.

[0018] Preferably, the back adhesive layer has a thickness of 10 to 50 um, and is coated on the nano heat dissipation base film layer by means of an organic silicon pressure-sensitive adhesive, dried, rolled up, and pasted on the release film layer.

[0019] Preferably, the thickness of the film system functional layer is 1.89 um, the thickness of the nano heat dissipation base film layer is 100 um, the thickness of the back adhesive layer is 30 um, and the thickness of the release film layer is 50 μm.

[0020] Preferably, the satellite thermal control film has a solar absorption ratio of no more than 0.10, a hemispherical emissivity of greater than 0.88, and an X (10 GHz) wave transmittance of greater than 99.0%.

[0021] A second aspect of the present invention provides a method for preparing the satellite wave-transmitting thermal control film, comprising the following steps:

[0022] (1) weighing a continuous phase fluororesin, zinc oxide, titanium oxide and a dispersant in proportion, mixing at high speed, melting and granulating the mixed particles through a twin-screw extruder, and melt-casting the obtained masterbatch through a single-screw casting machine to form a film, thereby obtaining a nano heat dissipation base film;

[0023] (2) ultrasonically cleaning the nano heat dissipation base film with ethanol and ultrapure water, and then periodically coating the surface of one side of the nano heat dissipation base film with titanium oxide and silicon oxide as targets by magnetron sputtering to form a film-based functional layer;

[0024] (3) curing the organic silicon pressure-sensitive adhesive liquid formed by condensation of silicone rubber and MQ resin on one surface of the nano heat dissipation base film on a coating machine to form a back adhesive layer;

[0025] (4) Covering the surface of the back adhesive layer with a layer of PET release film.

[0026] Preferably, in step (1), the mass percentages of the continuous phase fluororesin, zinc oxide, titanium oxide and dispersant are 50%, 45%, 4% and 1% respectively;

[0027] and / or the high-speed mixing is high-speed mixing for not less than 30 minutes at a rotation rate of not less than 1000 rpm;

[0028] and / or the melt granulation temperature is 220°C;

[0029] And / or the casting melt temperature is 230° C., and the rotation speed of the single-screw casting machine is 10 Hz.

[0030] Preferably, in step (2), the gas pressure is 1.5×10 -3 torr, and the cathode power is 50kW.

[0031] Preferably, in step (3), the curing temperature is 140° C. and the curing time is 3 minutes.

[0032] The third aspect of the present invention provides the application of the satellite wave-transmitting thermal control film in the wave transmission, heat dissipation and light pollution protection of mass-produced satellites.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] 1. The present invention combines the film functional layer with the nano heat dissipation base film to achieve the unification of light pollution protection, heat dissipation and wave transmission functions.

[0035] 2. The present invention adheres the film to the satellite surface without the need for a rotating mechanism, thereby reducing the complexity of the thermal control system and increasing reliability.

[0036] 3. The satellite wave-transmitting thermal control film of the present invention has a flexible structure and good adaptability. It can achieve a solar absorption ratio of no more than 0.10, a hemispheric emissivity of more than 0.88, an X (10GHz) wave transmittance of more than 99.0%, and a light pollution protection efficiency of more than 80.0%. It can be used for wave transmission, heat dissipation and light pollution protection of mass-produced satellites.

[0037] 4. The present invention forms a multilayer film system on the surface of the nano film to obtain excellent heat dissipation, wave transmission and light pollution prevention functions. The entire thermal control film adopts silicone pressure-sensitive adhesive to shorten the film-sticking cycle and has good adaptability. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 Schematic diagram of the structure of the satellite wave-transmitting thermal control film for preventing space light pollution in the embodiment.

[0039] Figure 2 It is the mirror reflection curve of the satellite wave-transmitting thermal control film in the embodiment. DETAILED DESCRIPTION

[0040] The present invention is described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those of ordinary skill in the art, several changes and improvements can also be made without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

[0041] The following embodiments provide a satellite wave-transmitting thermal control film for preventing space light pollution, which is a flexible structure composed of a film functional layer, a nano-heat dissipation base film layer, a backing layer and a release film layer, wherein:

[0042] The film system functional layer is a multilayer film system formed by sputtering or evaporation, and is a functional layer for preventing light pollution;

[0043] The nano heat dissipation base film layer is a radiation heat dissipation functional layer, which is a nano heat dissipation film made of polyimide or fluororesin and nano fillers;

[0044] The material of the back adhesive layer is silicone pressure-sensitive adhesive;

[0045] The material of the release film layer is PET release film, which is used to protect the adhesive layer.

[0046] In some embodiments, the thickness of the film functional layer is 0.2 to 2 um, and is composed of a high refractive index film layer and a low refractive index film layer; the high refractive index film is at least one of titanium oxide, tantalum oxide, zirconium oxide, hafnium oxide, and niobium oxide; the low refractive index film is at least one of silicon oxide, aluminum oxide, magnesium fluoride, and aluminum fluoride.

[0047] In some embodiments, the thickness of the nano heat dissipation base film layer is 50-200 um, and it is formed by melt casting of polyimide or fluororesin and nano filler.

[0048] In some embodiments, the nanofiller is at least one nanomaterial selected from the group consisting of titanium oxide, zinc oxide, zirconium oxide, aluminum oxide, and silicon oxide.

[0049] In some embodiments, the back adhesive layer has a thickness of 10 to 50 um, and is coated on the nano heat dissipation base film layer by means of an organic silicon pressure-sensitive adhesive, dried, rolled up, and pasted on the release film layer.

[0050] In some embodiments, the thickness of the film system functional layer is 1.89um, the thickness of the nano heat dissipation base film layer is 100um, the thickness of the back adhesive layer is 30um, and the thickness of the release film layer is 50μm.

[0051] Example 1

[0052] In this embodiment, a satellite wave-transmitting thermal control film for preventing space light pollution is prepared, and the steps are as follows:

[0053] Step A: Preparation of nano heat dissipation base film

[0054] Component A is a continuous phase fluororesin, with a weight ratio of 50%, component B is zinc oxide, with a weight ratio of 45%, component C is titanium oxide, with a particle size range of 200nm-2μm, and a dispersant, with a weight ratio of 1%. High-speed mixing is performed for no less than 30 minutes, and the rotation rate is no less than 1000 rpm. The mixed particles are melted and granulated by a twin-screw extruder, with a melting temperature of 220°C; the masterbatch is then melted and filmed by a single-screw casting machine, with a melting temperature of 230°C and a screw speed of 10Hz, to obtain a nano heat dissipation base film.

[0055] Step B: Preparation of membrane functional layer

[0056] The film surface was pre-treated first, and the nano heat dissipation base film was ultrasonically cleaned with ethanol and ultrapure water. Through magnetron sputtering, the target materials were titanium oxide and silicon oxide, the gas pressure was 1.5×10-3torr, and the cathode power was 50kW. The titanium oxide and silicon oxide film systems with different thicknesses were periodically plated on the base film layer. The specific thickness and number of layers are shown in Table 1.

[0057] Table 1

[0058] Film sequence Material Thickness(nm) 1 <![CDATA[SiO2]]> 77.5 2 <![CDATA[TiO2]]> 52.7 3 <![CDATA[SiO2]]> 0.0 4 <![CDATA[TiO2]]> 19.8 5 <![CDATA[SiO2]]> 8.3 6 <![CDATA[TiO2]]> 15.0 7 <![CDATA[SiO2]]> 4.6 8 <![CDATA[TiO2]]> 9.0 9 <![CDATA[SiO2]]> 2.7 10 <![CDATA[TiO2]]> 0.8 11 <![CDATA[SiO2]]> 163.6 12 <![CDATA[TiO2]]> 1.3 13 <![CDATA[SiO2]]> 3.4 14 <![CDATA[TiO2]]> 81.8 15 <![CDATA[SiO2]]> 126.2 16 <![CDATA[TiO2]]> 69.3 17 <![CDATA[SiO2]]> 110.6 18 <![CDATA[TiO2]]> 69.6 19 <![CDATA[SiO2]]> 112.2 20 <![CDATA[TiO2]]> 75.2 21 <![CDATA[SiO2]]> 106.6 22 <![CDATA[TiO2]]> 27.3 23 <![CDATA[SiO2]]> 73.3 24 <![CDATA[TiO2]]> 56.4 25 <![CDATA[SiO2]]> 91.7 26 <![CDATA[TiO2]]> 43.2 27 <![CDATA[SiO2]]> 49.5 28 <![CDATA[TiO2]]> 59.0 29 <![CDATA[SiO2]]> 32.4 30 <![CDATA[TiO2]]> 14.2 31 <![CDATA[SiO2]]> 261.9 32 <![CDATA[TiO2]]> 9.4 33 <![CDATA[SiO2]]> 69.8 Total thickness 1898.4

[0059] Step C: Pressure-sensitive adhesive coating

[0060] The silicone pressure-sensitive adhesive is mainly formed by the condensation of silicone rubber and MQ resin, and is cured with the nano heat dissipation base film on a coating machine. The curing temperature is 140°C and the curing time is 3 minutes.

[0061] Step D: Preparation of release film layer

[0062] After curing, a layer of PET release film with a thickness of 50 μm is applied on the surface coated with the pressure-sensitive adhesive to obtain the product.

[0063] After testing, the satellite wave-transmitting thermal control film prepared in this embodiment achieves a solar absorption ratio of no more than 0.09, a hemispherical emissivity of more than 0.90, a X (10GHz) wave transmittance of more than 99.0%, and a mirror reflectivity of 80.0% ( Figure 2 ), can be used for wave transmission, heat dissipation and light pollution protection of mass-produced satellites.

[0064] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A satellite wave-transmitting thermal control film for preventing space light pollution, characterized in that: It is a flexible structure composed of a film functional layer, a nano heat dissipation base film layer, a backing layer and a release film layer, among which: The film system functional layer is a multilayer film system formed by sputtering or evaporation, and is a functional layer for preventing light pollution; The nano heat dissipation base film layer is a radiation heat dissipation functional layer, which is a nano heat dissipation film made of polyimide or fluororesin and nano fillers; The material of the back adhesive layer is silicone pressure-sensitive adhesive; The release film layer is made of PET release film, which is used to protect the adhesive layer.

2. The satellite wave-transmitting thermal control film for preventing space light pollution according to claim 1, characterized in that: The thickness of the film functional layer is 0.2-2um, and it is composed of a high refractive index film layer and a low refractive index film layer; wherein the high refractive index film layer is at least one film selected from titanium oxide, tantalum oxide, zirconium oxide, hafnium oxide, and niobium oxide; And / or the low refractive index thin film layer is at least one thin film selected from silicon oxide, aluminum oxide, magnesium fluoride and aluminum fluoride.

3. The satellite wave-transmitting thermal control film for preventing space light pollution according to claim 1, characterized in that: The thickness of the nano heat dissipation base film layer is 50-200 um, and it is formed by melt casting of polyimide or fluororesin and nano filler; wherein the nano filler is at least one nano material selected from titanium oxide, zinc oxide, zirconium oxide, aluminum oxide, and silicon oxide.

4. The satellite wave-transmitting thermal control film for preventing space light pollution according to claim 1, characterized in that: The thickness of the back adhesive layer is 10-50 um, and it is coated on the nano heat dissipation base film layer by means of organic silicon pressure-sensitive adhesive, dried, rolled up, and pasted on the release film layer.

5. The satellite wave-transmitting thermal control film for preventing space light pollution according to claim 1, characterized in that: The thickness of the film system functional layer is 1.89um, the thickness of the nano heat dissipation base film layer is 100um, the thickness of the back adhesive layer is 30um, and the thickness of the release film layer is 50μm.

6. The satellite wave-transmitting thermal control film for preventing space light pollution according to claim 1, characterized in that: The satellite thermal control film has a solar absorption ratio of no more than 0.10, a hemispherical emissivity of more than 0.88, and an X (10 GHz) wave transmittance of more than 99.0%.

7. The method for preparing the satellite wave-transmitting thermal control film according to any one of claims 1 to 6, characterized in that: The following steps are involved: (1) weighing a continuous phase fluororesin, zinc oxide, titanium oxide and a dispersant in proportion, mixing at high speed, melting and granulating the mixed particles through a twin-screw extruder, and melt-casting the obtained masterbatch through a single-screw casting machine to form a film, thereby obtaining a nano heat dissipation base film; (2) ultrasonically cleaning the nano heat dissipation base film with ethanol and ultrapure water, and then periodically coating the surface of one side of the nano heat dissipation base film with titanium oxide and silicon oxide as targets by magnetron sputtering to form a film-based functional layer; (3) curing the organic silicon pressure-sensitive adhesive liquid formed by condensation of silicone rubber and MQ resin on one surface of the nano heat dissipation base film on a coating machine to form a back adhesive layer; (4) Covering the surface of the back adhesive layer with a layer of PET release film.

8. The method for preparing the satellite wave-transmitting thermal control film according to claim 7, characterized in that: In step (1), the mass percentages of the continuous phase fluororesin, zinc oxide, titanium oxide and dispersant are 50%, 45%, 4% and 1% respectively; and / or the high-speed mixing is high-speed mixing for not less than 30 minutes at a rotation rate of not less than 1000 rpm; and / or the melt granulation temperature is 220°C; And / or the casting melt temperature is 230° C., and the rotation speed of the single-screw casting machine is 10 Hz.

9. The method for preparing the satellite wave-transmitting thermal control film according to claim 7, characterized in that: In step (2), the gas pressure is 1.5×10 -3 torr, cathode power is 50kW; And / or in step (3), the curing temperature is 140° C. and the curing time is 3 min.

10. Application of the satellite wave-transmitting thermal control film according to any one of claims 1 to 6 in wave transmission, heat dissipation and light pollution protection of mass-produced satellites.

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