High-absorption and high-emission composite functional film coating material and preparation method thereof

Abstract

The application discloses a high-absorption and high-emission composite functional film coating material and a preparation method thereof, relates to the technical field of flexible film material preparation, and is characterized in that multi-scale materials such as carbon materials and inorganic ceramic particles are used as main functional units, and organic fluorine-containing resin is used as a binder to prepare a precursor slurry in an organic solvent, and a composite functional film is prepared through a scraping coating, spraying or other process method, so that the process is simple, the prepared film is a flexible film type super-black material, the film can be integrated with a satellite surface through double-sided adhesive tape, dark buckle lapping or other modes, the implementation cycle of the high-absorption and high-emission composite functional material can be greatly reduced, and the problem of poor high-temperature curing adaptability of the spraying and curing type super-black coating material is solved.

Description

Technical Field

[0001] This invention relates to the field of flexible thin film material preparation technology, specifically to a high-absorption, high-emission composite functional thin film coating material and its preparation method. Background Technology

[0002] With the continuous development of international space optical surveillance systems, the on-orbit safety and survivability of satellites are facing increasingly severe threats. Therefore, research on technologies to reduce on-orbit solar radiation detection by satellites has become a trend in satellite on-orbit safety research. Currently, there are many methods to reduce satellite solar radiation, among which spraying an ultra-black coating material onto the satellite surface is a simple and effective approach.

[0003] Superblack materials are materials with a reflectivity of less than 5% and an absorptivity of more than 95% within a certain range of incident light. Due to the thermal control design constraints of satellites operating in orbit, superblack materials are required to have high infrared emissivity, thereby achieving a composite functional superblack material that reduces solar detectability while maintaining thermal compatibility. This type of coating has wide applications in many fields such as optical equipment and aerospace. For example, in the internal structure of space telescopes, the use of superblack coatings can reduce stray light reflection and improve the imaging quality of the optical system.

[0004] From a thermal management perspective, when the ultra-black coating absorbs a large amount of visible light and electromagnetic radiation from other wavelengths, this energy is converted into heat. If the heat cannot be effectively dissipated, the temperature of the coating and the object it adheres to will continuously rise. This may lead to a decline in coating performance, such as material aging and deformation, and may even affect the accuracy of some high-precision equipment. Ultra-black coatings are mainly integrated onto satellite surfaces through processes such as spraying and high-temperature curing. However, with the continuous shortening of satellite development cycles, the gradual improvement of development efficiency, and the poor high-temperature adaptability of some materials, spray-cured ultra-black coating materials have significant limitations. Summary of the Invention

[0005] Therefore, the purpose of this invention is to provide a method for preparing a high-absorption, high-emission composite functional thin film.

[0006] The objective of this invention is achieved through the following technical solution:

[0007] <First Aspect>

[0008] This invention provides a composite functional film comprising a fluorinated resin, a first filler, and a second filler, wherein the mass ratio of the three components is (0.75-6):1:(2-5); the fluorinated resin is one or more of polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene, and polyvinylidene fluoride-trifluorochloroethylene; the first filler is one or more of zirconium oxide, silicon dioxide, and hafnium boride; and the second filler is one or more of high-pigment carbon black, carbon aerogel, and carbon spheres.

[0009] As one implementation, the thickness of the composite functional film is 50–100 μm.

[0010] <Second aspect>

[0011] This invention provides a method for preparing a high-absorption, high-emission composite functional thin film, comprising the following steps:

[0012] S1. Dissolve the fluorinated resin in an organic solvent, then add the first filler and the second filler, and mix them evenly by stirring to obtain the precursor slurry;

[0013] S2. The precursor slurry is coated onto the substrate surface by scraping or spraying, and then dried to obtain the composite functional film.

[0014] As one embodiment, the fluorinated resin is one or more of polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene, and polyvinylidene fluoride-trifluorochloroethylene.

[0015] As one implementation, the first filler is one or more of zirconium oxide, silicon dioxide, and hafnium boride.

[0016] In some embodiments, the first filler is one of monoclinic zirconium oxide, amorphous silicon dioxide, and amorphous hafnium boride.

[0017] As one implementation, the particle size of the first filler does not exceed 20 μm.

[0018] In some embodiments, the particle size of the first filler does not exceed 10 μm.

[0019] As one implementation, the second filler is one or more of high-pigment carbon black, carbon aerogel, and carbon spheres.

[0020] As one implementation, the particle size of the second filler is in the nanometer range.

[0021] As one embodiment, the organic solvent is one or more of N,N-dimethylformamide, N,N-dimethylacetamide, and butyl acetate.

[0022] In some embodiments, the organic solvent is N,N-dimethylacetamide or butyl acetate.

[0023] As one implementation, the mass ratio of the first packing material to the second packing material is 1:(2-5).

[0024] As one embodiment, the mass ratio of the fluorinated resin to the filler is 1:(1-4), and the filler is a first filler and a second filler.

[0025] As one implementation, in step S1, the stirring parameters are 300–600 r / min.

[0026] As one implementation, in step S1, the stirring process takes 1 to 4 hours.

[0027] As one implementation, in step S2, the substrate is selected as a glass substrate.

[0028] As one implementation, in step S2, the drying temperature is 50–100°C.

[0029] In one implementation scheme, the drying time in step S2 is 6 to 12 hours.

[0030] As one implementation scheme, the thickness of the prepared composite functional film is 50–100 μm.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] 1) This invention provides a method for preparing a high-absorption and high-emission composite functional film. The method uses multi-scale materials such as carbon materials and inorganic ceramic particles as the main functional units, and organic fluorinated resin as the binder. A precursor slurry is prepared in an organic solvent. The composite functional film is prepared by processes such as scraping and spraying. The process is simple. The prepared film is a flexible film-type ultra-black material that can be integrated with the satellite surface by means of double-sided tape, concealed fastening, etc. This can greatly reduce the implementation cycle of high-absorption and high-emission composite functional materials, and also solves the problem of poor high-temperature curing adaptability of spray-cured ultra-black coating materials.

[0033] 2) The high-absorption and high-emission composite functional film prepared by the present invention has a thickness of 50-100 μm, excellent thermal control performance (solar absorptivity and hemispherical emissivity), excellent vacuum degassing performance, and after undergoing 100 temperature shock tests in the temperature range of -100 to +100℃, it not only maintains its appearance but also has stable performance. It is a solar high-absorption and infrared high-emission composite functional film.

[0034] 3) From a thermal management perspective, the composite functional film prepared in this invention, after absorbing solar radiation, dissipates heat into space through enhanced infrared emission, ensuring that the satellite surface temperature remains within a suitable range. This not only guarantees the normal operation of precision instruments and equipment inside the satellite but also maintains the stability of the overall satellite structure. Furthermore, because the satellite reflects very little sunlight when facing solar radiation, the likelihood of it being detected by solar detection equipment is greatly reduced.

[0035] In summary, the high-absorption, high-emission composite functional thin film provided by this invention has excellent performance in reducing the solar detectability of satellites during on-orbit operation and being compatible with thermal control requirements. It solves the problems of poor compatibility between high-absorption solar materials for space applications and thermal control, long production cycles, and poor adaptability to high-temperature curing. Attached Figure Description

[0036] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0037] Figure 1 A flowchart illustrating the preparation method of the high-absorption, high-emission composite functional thin film provided by this invention;

[0038] Figure 2 This is a graph showing the solar absorption characteristics of the composite functional thin film prepared in Example 4 of the present invention.

[0039] Figure 3 Before the high and low temperature test of the composite functional thin film prepared in Example 4 of this invention ( Figure 3 (a) and after the experiment ( Figure 3 (b) Sample image. Detailed Implementation

[0040] The present invention will be described in detail below with reference to embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several adjustments and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0041] This specific embodiment provides a method for preparing a high-absorption, high-emission composite functional thin film, such as... Figure 1 As shown, it includes the following steps:

[0042] S1. Preparation of precursor slurry

[0043] Fluorine-containing resin is dissolved in an organic solvent, and then the first filler and the second filler are added. The mixture is stirred to make the slurry uniform, and the precursor slurry is obtained.

[0044] S2. Molding and preparing composite functional films

[0045] The precursor slurry is coated onto the substrate surface by scraping or spraying, and then dried to obtain a high-absorption and high-emission composite functional film with a thickness of 50–100 μm.

[0046] The following four examples illustrate the preparation method of high-absorption and high-emission composite functional thin films.

[0047] Example 1

[0048] In this embodiment, the substances and their amounts, by mass, are as follows:

[0049] Fluorinated resin: 3 parts polyvinylidene fluoride (PVDF);

[0050] First filler: 1 part high-pigment carbon black;

[0051] Second filler: 2 parts of monoclinic zirconium oxide with a particle size of 0.5-1μm;

[0052] Organic solvent: 3 parts N,N-dimethylacetamide.

[0053] In this embodiment, a thin film is coated on the surface of the glass substrate using a scraping method.

[0054] In step S1, the stirring parameters are: rotation speed 300 r / min, stirring time 1 h.

[0055] In step S2, the drying temperature is 100℃ and the drying time is 12h.

[0056] A high-absorption, high-emission composite functional film with a thickness of 55 μm was prepared.

[0057] Example 2

[0058] In this embodiment, the substances and their amounts, by mass, are as follows:

[0059] Fluorinated resin: 2 parts polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP);

[0060] First filler: 1 part carbon aerogel;

[0061] Second filler: 3 parts of 5-8 μm amorphous silica;

[0062] Organic solvent: 3 parts N,N-dimethylacetamide.

[0063] In this embodiment, a thin film is coated on the surface of the glass substrate using a scraping method.

[0064] In step S1, the stirring parameters are: rotation speed 400 r / min, stirring time 2 h.

[0065] In step S2, the drying temperature is 80℃ and the drying time is 10 hours.

[0066] A high-absorption, high-emission composite functional film with a thickness of 73 μm was prepared.

[0067] Example 3

[0068] In this embodiment, the substances and their amounts, by mass, are as follows:

[0069] Fluoropolymer: 5 parts polyvinylidene fluoride-chlorotrifluoroethylene (P(VDF-CTFE));

[0070] First filler: 3 parts of hollow carbon nanospheres with a diameter of 100-300 nm;

[0071] Second filler: 12 parts of amorphous hafnium boride with a diameter of 1-3 μm;

[0072] Organic solvent: 10 parts butyl acetate.

[0073] In this embodiment, a thin film is coated on the surface of the glass substrate using a scraping method.

[0074] In step S1, the stirring parameters are: 500 r / min speed and 3 h stirring time.

[0075] In step S2, the drying temperature is 50℃ and the drying time is 6 hours.

[0076] A high-absorption, high-emission composite functional film with a thickness of 96 μm was prepared.

[0077] Example 4

[0078] In this embodiment, the substances and their amounts, by mass, are as follows:

[0079] Fluorinated resin: 3 parts polyvinylidene fluoride-hexafluoropropylene;

[0080] First filler: 2 parts carbon aerogel;

[0081] Second filler: 10 parts of 5-8 μm silica;

[0082] Organic solvent: 7.5 parts N,N-dimethylacetamide.

[0083] In this embodiment, a thin film is coated on the surface of the glass substrate using a scraping method.

[0084] In step S1, the stirring parameters are: 600 r / min speed and 4 h stirring time.

[0085] In step S2, the drying temperature is 60℃ and the drying time is 8 hours.

[0086] A high-absorption, high-emission composite functional film with a thickness of 87 μm was prepared.

[0087] Test methods

[0088] (I) Coating thickness test

[0089] The thickness of the composite functional film was tested using an outside micrometer manufactured by Chengdu Chengliang Tool Group Co., Ltd. The measurement range was 0–25 mm, with an error of ±5 μm. The tested composite functional film thicknesses were between 55–96 μm (as described in each embodiment), meeting the technical specification requirement of 50 μm–100 μm.

[0090] (II) Solar Absorption Ratio Test

[0091] This experiment used a PerkinElmer LAMBDA 950 spectrophotometer to measure the solar absorptivity of composite functional thin films. It can measure wavelengths from 200 nm to 2500 nm, with a resolution of 0.1 nm, bandwidth ≤ 0.05 nm, stray light ≤ 0.00008%A, noise < 0.0008A, photometer repeatability < 0.0001A, baseline drift < 0.0002A / h, baseline flatness: ±0.001A, exhibiting good stability, high baseline flatness, and extremely low stray light. The step size was set to 5 nm, and the slit width to 4 nm.

[0092] (III) Hemispherical Emissivity Test

[0093] The hemispherical emissivity of the sample in the 3–35 μm band at room temperature was measured using a TEMP 2000A emissivity meter manufactured by AZ TECHNOLOGY. Its measurement accuracy is ±3% and the full-band repeatability is ±0.5%.

[0094] (iv) Vacuum venting performance test

[0095] A vacuum venting test was conducted according to standard GJB2704A-2006. The total mass loss (TML) and condensable volatile matter (CVCM) of the material in vacuum were measured and calculated. The test conditions are as follows:

[0096] Sample pretreatment: 23℃±1℃, humidity 45%RH±10%RH, maintain for 24h; sample heating temperature 125℃±1℃; condensable volatile matter collection temperature 25℃; test pressure ≤7×10 -3 Pa; Insulation time is 24 hours;

[0097] The sensitivity of the balance test is 1 μg.

[0098] (V) Thermal Cycling Test

[0099] The temperature shock chamber (model ZTS010, Shanghai Zengda Environmental Testing Equipment Co., Ltd.) was used, and the test was conducted according to the requirements of GJB2704A-2006 standard, under normal atmospheric conditions, through 100 thermal cycles at temperatures ranging from -100℃ to +100℃. The test conditions are as follows:

[0100] Test temperature: 100℃ at the high temperature end and -100℃ at the low temperature end; 100 cycles; temperature control error: ±5℃ at high temperature and ±10℃ at low temperature; the thermal cycling device should have two constant temperature zones with different temperatures, and the sample should be transferred from one constant temperature zone to the other within 10 seconds; keep the sample at the high and low temperature ends for 10 minutes to ensure that the sample temperature is the same as the ambient temperature; dehumidification measures should be taken during the test to prevent frost from forming on the surface of the sample.

[0101] Test Results and Analysis

[0102] The composite functional films prepared in Examples 1, 2, 3, and 4 above were subjected to performance tests, and the test results are listed in Table 1. The solar absorption characteristic curves and sample images before and after high and low temperature tests for Example 4 are shown in the figures below. Figure 2 and Figure 3 As shown.

[0103] Table 1 Performance test data of the composite functional films prepared in each embodiment

[0104]

[0105]

[0106] As shown in Table 1, the properties of the composite functional thin film prepared by the present invention are as follows:

[0107] Appearance: Black, with a uniform coating surface;

[0108] Thickness: 50μm-100μm;

[0109] Solar absorptivity: 0.95–0.98;

[0110] Hemispherical emissivity: 0.88–0.93;

[0111] Thermal cycling test: The high-absorption and high-emission composite functional film has passed 100 high and low temperature thermal cycling tests from -100 to +100℃ and its appearance remains intact and its optical performance remains stable.

[0112] Vacuum venting performance: all meet the requirements of TML<1% and CVCM<0.1%.

[0113] It can be seen that the high-absorption and high-emission composite functional film prepared by the present invention has the advantages of simple preparation process and short integration cycle with satellite surface, while reducing the solar detectability of satellites during on-orbit operation and being compatible with thermal control performance (solar absorptivity and hemispherical emissivity). It has strong feasibility and its appearance is intact and its performance is stable after undergoing 100 temperature shock tests in the temperature range of -100 to +100℃.

[0114] The specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various modifications or variations within the scope of the claims, which do not affect the essence of the present invention.

Claims

1. A composite functional thin film, characterized in that, The material includes a fluorinated resin, a first filler, and a second filler, wherein the mass ratio of the fluorinated resin, the first filler, and the second filler is (0.75~6):1:(2~5), and the mass ratio of the fluorinated resin to the filler is 1:(1~4), wherein the filler is the first filler and the second filler. The fluorinated resin is one or more of polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene, and polyvinylidene fluoride-trifluorochloroethylene; the first filler is one or more of high-pigment carbon black, carbon aerogel, and carbon spheres; the second filler is amorphous hafnium boride; the particle size of hafnium boride is 1~3 μm; The composite functional film is a flexible film-type ultra-black material.

2. The composite functional film according to claim 1, characterized in that, The thickness of the film is 50~100 μm.

3. The method for preparing the composite functional thin film according to any one of claims 1 to 2, characterized in that, Includes the following steps: S1. Dissolve the fluorinated resin in an organic solvent, then add the first filler and the second filler, and mix them evenly by stirring to obtain the precursor slurry; S2. The precursor slurry is coated onto the substrate surface and dried to obtain the composite functional film.

4. The method for preparing the composite functional thin film according to claim 3, characterized in that, The organic solvent is one or more of N,N-dimethylformamide, N,N-dimethylacetamide, and butyl acetate.

5. The method for preparing the composite functional thin film according to claim 3, characterized in that, The stirring parameters are 300~600 r / min and the time is 1~4 h.

6. The method for preparing the composite functional thin film according to claim 3, characterized in that, The drying temperature is 50~100℃.

7. The method for preparing the composite functional thin film according to claim 3, characterized in that, In step S2, the substrate is selected as a glass substrate.

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