Anti-atomic oxygen protective coating for polyimide surface and preparation method of anti-atomic oxygen protective coating

Abstract

The invention discloses an anti-atomic oxygen protective coating for a polyimide surface. The anti-atomic oxygen protective coating comprises the following raw materials: organic silicon resin, polyester modified organic silicon resin, a coloring pigment, flaky nanoparticles, needle-shaped nanoparticles, micron particles, an auxiliary agent, a solvent and a curing agent, organic silicon resin and modified organic silicon resin are used as matrix resin, nano particles with different sizes and shapes and micron-sized spherical particles with different melting points are added, a curing agent is added after uniform ultrasonic dispersion, a base material is coated with the mixture through a blade coating technology, baking and curing are conducted at the temperature of 200 DEG C to form a film, and a coating obtained after film forming has excellent high and low temperature resistance; the coating has excellent adhesive force on the surface of a polyimide film, and has excellent ultraviolet radiation resistance, atomic oxygen resistance and the like.

Description

Technical Field

[0001] The invention belongs to the technical field of fine chemical coating materials and applications, and particularly relates to an antiproto-oxygen protective coating for a polyimide surface and a preparation method thereof. Background Art

[0002] Low-Earth orbit (LEO) is the primary operating zone for spacecraft, including artificial satellites, space shuttles, manned spacecraft, and space stations. The LEO environment is primarily characterized by atomic oxygen (AO), ultraviolet radiation (UV), charged particles, space debris, and a high vacuum. Atomic oxygen, formed by the dissociation of residual oxygen molecules in the LEO environment by solar ultraviolet light (wavelength <243 nm), is a highly potent oxidant (far more potent than molecular oxygen) and can react directly with materials. Furthermore, when a spacecraft encounters atomic oxygen traveling at speeds of 8 km / s, it generates collisional kinetic energy (approximately 5.3 eV). Consequently, the presence of atomic oxygen in LEO can severely abrade surface materials, leading to loss of material quality and thickness, changes in surface morphology, alterations in thermal, optical, and electrical properties, changes in structure and mechanical properties, and even failure. This poses the greatest threat to the reliable operation of long-life civilian spacecraft in LEO.

[0003] Polyimide (PI) is a type of polymer with imide aromatic heterocycles. It has excellent high and low temperature resistance and can be used for a long time at 400°C. It will not crack even in liquid helium at an extremely low temperature (-269°C). It has excellent mechanical properties, good dimensional stability, and a low dielectric constant. Therefore, it is widely used in thermal protection materials and thin film materials in the aerospace field. However, the atomic oxygen stripping rate of polyimide material is as high as 3.0×10 -24 ㎝ -3 .atom -1 Data shows that a 25μm-thick polyimide film exposed to a 400km track for approximately 10 months will be completely eroded by atomic oxygen. Therefore, protecting polyimide surfaces from atomic oxygen is an important research topic.

[0004] The main protective measures against anti-proton oxygen on the surface of polyimide are: ① New anti-proton oxygen materials, which are to introduce elements such as phosphorus (P), zirconium (Zr), and silicon (Si) into the molecular structure of PI, such as introducing cage-shaped oligomeric semisiloxane (POSS) containing Si groups into the PI structure. After contact with oxygen atoms, the Si-containing groups react with oxygen atoms to form a SiO2 passivation layer, which can effectively improve the anti-proton oxygen performance of PI; ② Use thermal spraying methods such as vacuum evaporation, plasma spraying, magnetron sputtering and physical / chemical deposition methods to form a dense metal layer, SiO2 layer and AI2O3 layer on the PI surface; ③ Coat a layer of polysiloxane organic coating on the surface of the PI film. When the spacecraft enters low orbit, the Si-containing groups in the coating react with oxygen atoms after contact with oxygen atoms to form a SiO2 passivation layer, thereby improving the anti-proton oxygen performance of the PI film.

[0005] In the above technical solutions, the new anti-oxygen materials, whether containing POSS structures in the main chain or in the side chains, can form a dense SiO2 passivation layer on the surface of the PI film after contact with atomic oxygen, showing excellent anti-oxygen properties. However, their high cost seriously restricts their large-scale engineering applications. In solution 2, a metal layer or metal oxide layer is plated on the surface of the PI film, which can also significantly improve the anti-oxygen properties of the PI film. However, such films are difficult to apply to subsequent coatings. If a coating is applied to the surface of such a film, the volume shrinkage generated during the curing of the coating can easily cause the coating to crack or fall off, reducing its anti-oxygen properties. Therefore, this method cannot impart other functions to the PI film. In solution 3, a conventional polysiloxane organic coating is used, and the SiO2 passivation layer formed has a loose and rough structure with large surface gaps. This structure increases the number of collisions between atomic oxygen and the material surface. Multiple collisions not only increase the probability of atomic oxygen reacting with the material surface, but also may cause atomic oxygen to enter the coating through the gaps and even reach the substrate, causing "erosion" and limiting its anti-oxygen protection effect. Summary of the Invention

[0006] The present invention aims to provide an antiproto-oxygen protective coating for polyimide surfaces and a method for preparing the same. The coating is prepared by adding nanoparticles of varying sizes and shapes and micron-sized spherical particles of varying melting points to a base resin of silicone resin and modified silicone resin. Ultrasonic dispersion is then performed uniformly, followed by curing with a silane coupling agent at 200°C to form a film. The resulting coating exhibits excellent high and low temperature resistance, excellent adhesion to the polyimide film surface, and excellent resistance to ultraviolet radiation and antiproto-oxygen.

[0007] In order to achieve the above object, the present invention provides an antiproto-oxygen protective coating for polyimide surface, which comprises the following components in parts by weight:

[0008]

[0009] Furthermore, the silicone resin is one or a mixture of Dow's DC806A, DC805, Shin-Etsu's KR-220L, KR-311, Maitu's SR240YI, domestic Chenguangyuan 1053 and Bluestar's GSR-100.

[0010] Furthermore, the modified silicone resin is a polyester modified silicone resin

[0011] Furthermore, the coloring pigment is an inorganic pigment.

[0012] Furthermore, the flaky nanoparticles are one or a mixture of graphene, carbon nanosheets, silver nanosheets, nano-zinc oxide, nano-aluminum oxide, and nano-titanium dioxide. The addition of the flaky nanoparticles enhances the mirror effect of the coating, reduces the probability of atomic oxygen contacting the coating surface, and prevents atomic oxygen from entering the coating interior, further enhancing the overall coating's anti-oxygen properties.

[0013] Furthermore, the needle-shaped nanoparticles are selected from the group consisting of single-arm carbon nanotubes, multi-arm carbon nanotubes, silver nanoneedles, zinc oxide nanoneedles, and ferroferric oxide nanoneedles, or a mixture thereof. The addition of the needle-shaped nanoparticles enhances the antistatic properties of the coating surface, prevents energy accumulation on the coating surface, and improves the coating's anti-bending properties.

[0014] Furthermore, the spherical micron particles are a mixture of silicon-containing particles with different melting points. The addition of these spherical micron particles causes the coating to melt when subjected to atomic oxygen collisions, forming a single layer with the SiO2 passivation layer formed after the silicone resin is oxidized. This reduces the surface roughness of the coating after exposure to atomic oxygen, decreases the probability of atomic oxygen colliding with the coating surface, improves the coating's resistance to atomic oxygen, forms a denser passivation layer, and prevents the occurrence of "erosion";

[0015] Furthermore, the additive is one or a mixture of BYK163, BYK110, BYK P104, BYK P104S, BYK1790, BYK054, BYK066N, and BYK358N.

[0016] Furthermore, the solvent is xylene.

[0017] Furthermore, the curing agent is one or a mixture of KH550, KH560, and ND-42.

[0018] A second aspect of the present invention provides a method for preparing the aforementioned antiproto-oxygen protective coating for polyimide surfaces. The method comprises adding a resin, solvent, and additives to a jar of a predetermined volume, stirring at high speed for 20 minutes, then adding nanoparticles, micronized particles, and a coloring pigment. Ultrasonic dispersion is performed until the particle size is less than 10 μm. After filtration, a curing agent is added. The mixture is stirred thoroughly and then applied to the substrate by knife coating. After surface drying, the coating is then cured in a 200°C oven for 2 minutes. The knife coating process results in a coating with improved surface smoothness and gloss, and more uniform arrangement of the flaky and needle-shaped nanoparticles, further improving the coating's antiproto-oxygen properties.

[0019] The addition ratio of needle-shaped nanoparticles, flaky nanoparticles and spherical micron particles of the present invention enables the coating to have good antiproto-oxygen resistance and excellent mechanical properties; the compounding of silicone resin and modified silicone resin enables the coating to have high and low temperature resistance and antiproto-oxygen resistance while having excellent adhesion to the polyimide substrate.

[0020] Beneficial effects

[0021] The polyimide surface anti-proton oxygen protective coating prepared by the present invention has excellent high and low temperature resistance (-200 ℃ ~ 170 ℃, the coating does not crack or fall off after 10 cycles); has excellent ultraviolet radiation resistance (total radiation 364KCal / cm 2 The coating is smooth, does not crack, and does not fall off); the coating has excellent anti-atomic oxygen performance (atomic oxygen stripping rate <0.01×10 -24 cm -3 atom -1 ); At the same time, the coating has excellent adhesion on the surface of the polyimide film, with a T-bend of 0, and can be rubbed without falling off. DETAILED DESCRIPTION

[0022] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other implementation methods obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0023] Example 1:

[0024] formula:

[0025] Raw material name Addition amount (g) DC806A 20 Polyester modified silicone 16 Light chrome yellow 8 Nanosilver flakes 4 Single-arm carbon nanotubes 4 350℃ melting point silicon particles 3.6 450℃ melting point silicon particles 2.0 BYK1790 0.06 BYK110 0.06 Xylene 42.3 KH-550 1.0

[0026] Add DC806A, polyester-modified silicone resin, xylene, BYK1790, and BYK110 into a 500ml plastic jar according to the formula amount. After high-speed stirring for 20 minutes, add light chrome yellow, nanosilver flakes, single-arm carbon nanotubes, silicon-containing particles with a melting point of 350°C, and silicon-containing particles with a melting point of 450°C. Ultrasonic dispersion is carried out until the fineness is less than 10μm. After filtering, add KH-550, stir well, and apply it to the substrate. After the surface is dry, bake in a 200°C oven for 2 minutes.

[0027] The properties of the coating after baking and curing are shown in the following table:

[0028]

[0029]

[0030] Example 2:

[0031] formula:

[0032] Raw material name Addition amount (g) DC806A 22 Polyester modified silicone 20 Titanium dioxide 9 Nanosilver flakes 5 Fe3O4 nanoneedles 4 350℃ melting point silicon particles 4.6 550℃ melting point silicon particles 2.6 BYK1790 0.05 BYK110 0.08 Xylene 32.7 KH-550 1.5

[0033] Add DC806A, polyester-modified silicone resin, xylene, BYK1790, and BYK110 to a 500ml plastic jar according to the formula. After high-speed stirring for 20 minutes, add light chrome yellow, nanosilver flakes, ferroferric oxide nanoneedles, silicon-containing particles with a melting point of 350°C, and silicon-containing particles with a melting point of 550°C. Ultrasonic dispersion is carried out until the fineness is less than 10μm. After filtering, KH-550 is added, stirred well, and then applied to the substrate by scraper. After the surface is dry, it is placed in a 200°C oven for baking and curing for 2 minutes.

[0034] The properties of the coating after baking and curing are shown in the following table:

[0035]

[0036]

[0037] The present disclosure has been described using the aforementioned embodiments. However, the aforementioned embodiments are merely exemplary embodiments of the present disclosure. It should be noted that the disclosed embodiments do not limit the scope of the present disclosure. On the contrary, modifications and alterations made without departing from the spirit and scope of the present disclosure are within the scope of patent protection of the present disclosure.

Claims

1. An antiproto-oxygen protective coating for a polyimide surface, characterized in that: The raw materials are calculated by weight and consist of the following components:

2. The anti-proton oxygen protective coating for polyimide surface according to claim 1, characterized in that: The silicone resin is one or a mixture of DC806A, DC805 of Dow, KR-220L, KR-311 of Shin-Etsu, SR240YI of Momentive, domestic Chenguangyuan 1053 and GSR-100 of Bluestar.

3. The anti-proton oxygen protective coating for polyimide surface according to claim 1, characterized in that: The flaky nanoparticles are one or a mixture of graphene, carbon nanosheets, nanosilver sheets, nano zinc oxide, nano aluminum oxide, and nano titanium dioxide.

4. The anti-proton oxygen protective coating for polyimide surface according to claim 1, characterized in that: The needle-shaped nanoparticles are one or a mixture of single-arm carbon nanotubes, multi-arm carbon nanotubes, silver nanoneedles, zinc oxide nanoneedles, and ferroferric oxide nanoneedles.

5. The anti-proton oxygen protective coating for polyimide surface according to claim 1, characterized in that: The spherical micron particles are a mixture of silicon-containing particles with different melting points.

6. The anti-proton oxygen protective coating for polyimide surface according to claim 1, characterized in that: The auxiliary agent is one or a mixture of BYK163, BYK110, BYK P104, BYK P104S, BYK1790, BYK054, BYK066N, and BYK358N.

7. The anti-proton oxygen protective coating for polyimide surface according to claim 1, characterized in that: The solvent is xylene.

8. The anti-proton oxygen protective coating for polyimide surface according to claim 1, characterized in that: The curing agent is one or a mixture of KH550, KH560, and ND-42.

9. The anti-proton oxygen protective coating for polyimide surface according to claim 1, characterized in that: The coloring pigment is an inorganic pigment.

10. A method for preparing an antiproto-oxygen protective coating for a polyimide surface according to any one of claims 1 to 9, characterized in that: The method comprises the following steps: preparing materials according to a formula, adding silicone resin, polyester-modified silicone resin, solvent, and additives into a tank of a certain volume, stirring at high speed for 20 minutes, adding flaky nanoparticles, needle-shaped nanoparticles, spherical micron particles, and coloring pigments in sequence, ultrasonically dispersing the particles until the fineness is less than 10 μm, adding a curing agent after filtering, stirring evenly, and applying the mixture on a substrate by scraping. After the surface is dry, the mixture is placed in a 200°C oven for baking and curing for 2 minutes.

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