A coating with the functions of invisibility, heat insulation and heat resistance, a preparation method and application thereof

Abstract

The present application relates to the field of aerospace vehicle outer heat protection stealth material, and particularly relates to a coating with stealth, heat insulation and heat protection functions, a preparation method and application thereof.The coating with stealth, heat insulation and heat protection functions comprises the following raw materials by weight: 80-100 parts of silicone rubber, 30-50 parts of core-shell filler, 5-20 parts of ablation-resistant filler, 5-15 parts of shape-retaining filler, 3-5 parts of crosslinking agent, 0.1-1 part of catalyst and 200-300 parts of diluent.Comparative tests show that the coating has high hardness, high tensile strength and high shear strength, and good comprehensive mechanical properties;at the same time, the coating has excellent ablation resistance, heat insulation performance and wave absorption performance.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of aerospace vehicle outer heat-shielding stealth materials, and particularly relates to a coating with stealth, heat insulation and heat protection functions, a preparation method and application thereof. BACKGROUND

[0002] With the development of aerospace and military industries, higher requirements are put forward for the penetration capability of military equipment, and long-range high-altitude flying weapons, hypersonic strike weapons and other equipment have become the focus of development of various countries. Under high-speed flight conditions, weapon equipment will be subjected to harsh conditions such as high-temperature airflow scouring, oxidation and gas corrosion of 800 DEG C or even above 1000 DEG C, and not only needs to have excellent high-temperature ablation resistance, but also needs to have good penetration capability. Therefore, as the "protective clothing" of the aircraft equipment, the thermal protection material on the surface of the equipment shell not only needs to have excellent heat protection and heat insulation performance, but also needs to have good stealth and wave absorption performance, and relatively low density.

[0003] At present, there are two ways to realize the stealth function of equipment in high-temperature environment: one is to use stealth patches in combination with heat protection and insulation coatings, but this method not only has a complex construction process, but also increases the negative mass of the equipment, hindering the substantial improvement of the weapon penetration capability; the other is to use stealth fillers in combination with heat protection and insulation fillers, but this way easily weakens the wave absorption function of the stealth fillers, and it is difficult to achieve the ideal stealth effect.

[0004] Therefore, based on this, the technical scheme of the present application is proposed. SUMMARY

[0005] In order to solve the problems existing in the prior art, the scheme of the present application provides a coating with stealth, heat insulation and heat protection functions, which comprises the following raw materials by weight: 80-100 parts of silicone rubber, 30-50 parts of core-shell filler, 5-20 parts of ablation-resistant filler, 5-15 parts of shape-retaining filler, 3-5 parts of crosslinking agent, 0.1-1 part of catalyst and 200-300 parts of diluent.

[0006] Preferably, the silicone rubber is one or a combination of two or more of methyl silicone rubber, vinyl silicone rubber, phenyl silicone rubber, benzene-silicone rubber and phenyl ether-silicone rubber;

[0007] And / or, the viscosity of the silicone rubber is 3000-10000 mPa.s.

[0008] Preferably, the core-shell filler takes hollow heat insulation filler as the core, phenolic resin as the first layer of shell, and polycarbosilane (or Si and C-containing polysilane organic matter) as the second layer of shell or shell.

[0009] And / or, the hollow heat insulation filler is one or a combination of two or more of hollow glass microspheres, hollow phenolic microspheres and floating beads.

[0010] Preferably, the ablation-resistant filler is one or a combination of two or more of fumed silica, diatomite, mica powder, low-melting-point glass powder, kaolin, and silicon micro powder.

[0011] Preferably, the reinforcing filler is one or a combination of two or more of chopped quartz fiber, chopped glass fiber, high-silica fiber, and mullite fiber.

[0012] Preferably, the crosslinking agent is a siloxane crosslinking agent; the siloxane crosslinking agent is one or a combination of two or more of a ketoxime silane crosslinking agent, an allyloxy silane crosslinking agent, an amido silane crosslinking agent, and an aminoxyl silane crosslinking agent.

[0013] Preferably, the catalyst is one or a combination of two or more of an organic tin catalyst, a guanidino hydroxyl alkoxyl silane catalyst, a titanate catalyst, and a titanate complex catalyst.

[0014] Preferably, the diluent is one or a combination of two or more of No. 120 solvent oil, ethyl acetate, and dimethylbenzene.

[0015] Based on the same technical concept, another aspect of the present application provides a preparation method of a coating with the functions of stealth, heat insulation, and heat protection, the preparation method comprising the following steps:

[0016] (1) pre-mixing and grinding and dispersing silicone rubber, ablation-resistant filler, crosslinking agent, and part of diluent to obtain a first component;

[0017] (2) pre-mixing and grinding and dispersing core-shell filler, reinforcing filler, catalyst, and the rest of diluent to obtain a second component;

[0018] (3) mixing the first component and the second component uniformly to obtain the coating with the functions of stealth, heat insulation, and heat protection.

[0019] Based on the same technical concept, another aspect of the present application provides an application of the coating with the functions of stealth, heat insulation, and heat protection in a high-speed aircraft.

[0020] In order to facilitate the understanding of the present application, the principle of the present application is described:

[0021] The hollow microbead is used as the core of the core-shell filler, the closed cavity has low heat transfer characteristics; the phenolic resin is used as the first layer shell of the core-shell filler, and carbonization occurs when it undergoes a high-temperature ablation process, and the core-shell filler has a medium-high frequency wave absorption performance; the polycarbosilane is used as the second layer shell of the core-shell filler, and SiC is formed when it undergoes a high-temperature ablation process, and the core-shell filler has good high-temperature resistance; more importantly, the two-layer shell structure has different dielectric properties, can form an interface polarization effect, and thus dissipate electromagnetic wave energy. The silicone rubber has good wave-penetrating performance, can reduce the reflection of electromagnetic waves, and enhances the stealth effect of the coating. The ablation-resistant filler itself or its high-temperature reaction product has good high-temperature resistance, and together with the SiC formed in the high-temperature ablation process, forms an ablation-resistant layer, enhancing the heat-proof function of the coating. The reinforcing filler can enhance the carbonized layer, and improve the airflow scouring resistance and heat-proof function of the coating. The crosslinking agent can crosslink and solidify the silicone rubber, the catalyst can accelerate the crosslinking and solidification of the silicone rubber, and the diluent can adjust the workability of the slurry, and the three together can promote the formation of the outer heat-proof coating. In summary, the raw material components of the present application integrate the functions of stealth, heat insulation and heat resistance into one, are uniformly distributed in the outer heat-proof coating, and can also form an effective stealth structure.

[0022] The present application has the following advantages:

[0023] 1. The coating material has uniform distribution of raw material components, wherein: the core-shell filler cooperates with the silicone rubber with good wave-penetrating performance as the main component, compared with the simple mixing design of the heat-insulating and stealth integrated material in the prior art, the wave absorption performance and heat insulation performance of the coating material can be significantly improved, and the density of the coating can be reduced.

[0024] 2. In the coating material, the polysilicon carbon on the surface of the core-shell filler has high activity, compared with the prior art of directly adding Si powder and resin, carbon fiber to form SiC phase, the temperature for forming the high-temperature resistant phase in the coating is significantly reduced, and the ablation resistance of the coating material is improved.

[0025] 3. In the preparation process, the related raw materials such as the core-shell filler do not need to be subjected to high-temperature calcination treatment, but use the aerodynamic heat environment to generate the expected reaction product, thereby the cost can be significantly saved, the energy consumption is reduced, and the process flow is simplified. BRIEF DESCRIPTION OF DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor on the basis of these drawings.

[0027] Figure 1is an electron microscope image of the hollow thermal insulation filler and core-shell filler; wherein:

[0028] Figure 1 (a) in is an electron microscope image of the hollow thermal insulation filler;

[0029] Figure 1 (b) in is an electron microscope image of the core-shell filler.

[0030] Figure 2 is a comparison chart of the wave-absorbing performance of the coatings obtained in Examples 1-3 and Comparative Example 1. DETAILED DESCRIPTION

[0031] In order to make the objects, technical solutions and advantages of the present application clearer, the technical solutions of the present application will be described in detail below. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of protection of the present application.

[0032] Example 1

[0033] The present embodiment provides a preparation method of a coating with the functions of stealth, thermal insulation and heat protection, which comprises the following steps:

[0034] (1) 80 g of phenyl silicone rubber, 10 g of fumed silica, 5 g of low-melting-point glass powder, 3 g of siloxane crosslinking agent and 100 g of No. 120 solvent oil are pre-mixed and ground and dispersed to obtain a first component;

[0035] (2) 30 g of core-shell filler, 5 g of chopped quartz fiber, 0.1 g of organotin catalyst and 100 g of No. 120 solvent oil are pre-mixed and ground and dispersed to obtain a second component;

[0036] (3) The first component and the second component are mixed uniformly to obtain the coating with the functions of stealth, thermal insulation and heat protection.

[0037] Example 2

[0038] The present embodiment provides a preparation method of a coating with the functions of stealth, thermal insulation and heat protection, which comprises the following steps:

[0039] (1) 100 g of methyl silicone rubber, 15 g of fumed silica, 5 g of low-melting-point glass powder, 5 g of siloxane crosslinking agent and 100 g of No. 120 solvent oil are pre-mixed and ground and dispersed to obtain a first component;

[0040] (2) 50 g core-shell filler, 5 g chopped quartz fiber, 1 g organic tin catalyst, 200 g No. 120 solvent oil are premixed and ground and dispersed to obtain a second component;

[0041] (3) The first component and the second component are uniformly mixed to obtain the coating with the functions of stealth, heat insulation and heat protection.

[0042] Example 3

[0043] The embodiment provides a preparation method of a coating with the functions of stealth, heat insulation and heat protection, and the preparation method comprises the following steps:

[0044] (1) 100 g methyl silicone rubber, 15 g fumed silica, 5 g low-melting-point glass powder, 5 g siloxane crosslinking agent, 100 g No. 120 solvent oil are premixed and ground and dispersed to obtain a first component;

[0045] (2) 50 g core-shell filler, 15 g chopped quartz fiber, 1 g organic tin catalyst, 200 g No. 120 solvent oil are premixed and ground and dispersed to obtain a second component;

[0046] (3) The first component and the second component are uniformly mixed to obtain the coating with the functions of stealth, heat insulation and heat protection.

[0047] Comparative Example 1

[0048] The comparative example provides a preparation method of a coating, and the preparation method comprises the following steps:

[0049] (1) 80 g phenyl silicone rubber, 10 g fumed silica, 5 g low-melting-point glass powder, 3 g siloxane crosslinking agent, 100 g No. 120 solvent oil are premixed and ground and dispersed to obtain a first component;

[0050] (2) 30 g hollow heat insulation filler, 5 g chopped quartz fiber, 0.1 g organic tin catalyst, 100 g No. 120 solvent oil are premixed and ground and dispersed to obtain a second component;

[0051] (3) The first component and the second component are uniformly mixed to obtain the coating with the functions of stealth, heat insulation and heat protection.

[0052] The difference between Comparative Example 1 and Example 1 lies in that in step (2), Comparative Example 1 does not use core-shell filler but uses hollow heat insulation filler (the hollow heat insulation filler is the core layer of the core-shell filler) with the same weight.

[0053] For intuitive comparison and understanding, the electron microscope image of the hollow heat insulation filler is shown in (a) of Figure 1 , and the core-shell filler is shown in (b) of Figure 1 .

[0054] Test comparison

[0055] The coatings obtained in Examples 1-3 and Comparative Example 1 were tested using the following method: when the viscosity of the corresponding coating reached about 20 seconds using a four-cup measuring cup, a small brake spraying device was used to spray the sample. The sample was considered complete after curing at room temperature for 7 days, and testing could then begin.

[0056] The mechanical properties of the corresponding coatings were tested, and the data are shown in Table 1.

[0057] Table 1

[0058]

[0059]

[0060] As shown in Table 1, compared with Comparative Example 1, replacing 30g of hollow insulating filler with filler having a core-shell structure resulted in increased coating density, hardness, and strength in Example 1. Furthermore, a comparison between Example 3 and Example 2 shows that increasing the 5g dimensional filler (short-cut quartz fiber, hereinafter the same) to 15g resulted in a slight decrease in density and strength.

[0061] The ablation resistance of the coatings obtained in Examples 1-3 and Comparative Example 1 was tested using an electric arc micro wind tunnel. The ablation amount and back temperature of the samples are shown in Table 2.

[0062] Table 2

[0063] Group Ablative thinning mm Windward face temperature / °C Panel back temperature / °C Comparative Example 1 1.78 812 155 Example 1 1.65 805 170 Example 2 1.80 810 185 Example 3 1.75 820 176

[0064] Analysis of the data in Table 2 shows that core-shell fillers effectively improve the ablation resistance of the coating, but increase the thermal conductivity of the material; dimensional fillers effectively improve the ablation resistance and thermal insulation performance of the material. Therefore, the coating described in this invention has good ablation resistance and thermal insulation properties.

[0065] The microwave absorption properties of the coatings obtained in Examples 1-3 and Comparative Example 1 were tested, and the results are as follows: Figure 2 As shown. By Figure 2 It can be seen that the coatings obtained in Examples 1 to 3 have a large reflection loss near 10 GHz, indicating that the core-shell filler significantly improves the microwave absorption performance of the material; the combination of the dimensional filler and the core-shell filler improves the microwave absorption performance of the material.

[0066] The above merely illustrates the specific embodiments of the present application, but the protection scope of the present application is not limited thereto, any person skilled in the art can easily think of the changes or replacements within the technical range disclosed by the present application, which should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A coating that combines stealth, heat insulation, and heat protection functions, characterized in that, The raw materials include the following parts by weight: 80-100 parts silicone rubber, 30-50 parts core-shell filler, 5-20 parts ablation-resistant filler, 5-15 parts woven filler, 3-5 parts crosslinking agent, 0.1-1 parts catalyst, and 200-300 parts diluent; The core-shell filler consists of a core, a first shell, and a second shell: a hollow thermal insulation filler is used as the core, phenolic resin is used as the first shell, and polycarbosilane is used as the second shell; the specific preparation process is as follows: a hollow thermal insulation filler is used, the surface of the hollow thermal insulation filler is wrapped with phenolic resin, and then the surface of the resin is wrapped with polycarbosilane to form a core-shell filler with a composite core-shell structure. The hollow thermal insulation filler is one or a combination of two or more of the following: hollow glass microspheres, hollow phenolic microspheres, and cenospheres. The dimensional filler is one or a combination of two or more of the following: chopped quartz fiber, chopped glass fiber, high silica fiber, and mullite fiber.

2. The coating with stealth, heat insulation, and heat protection functions according to claim 1, characterized in that, The silicone rubber is one or a combination of two or more of methyl silicone rubber, vinyl silicone rubber, phenyl silicone rubber, phenylene silicone rubber, and phenyl ether silicone rubber. And / or, the viscosity of the silicone rubber is 3000~10000 mPa·s.

3. The coating with stealth, heat insulation, and heat protection functions according to claim 1, characterized in that, The ablation-resistant filler is one or a combination of two or more of the following: fumed silica, diatomaceous earth, mica powder, low-melting-point glass powder, kaolin, and silica micropowder.

4. The coating with stealth, heat insulation, and heat protection functions according to claim 1, characterized in that, The crosslinking agent is a siloxane crosslinking agent; the siloxane crosslinking agent is one or a combination of two or more of ketoxime silane crosslinking agents, allyloxy silane crosslinking agents, and amide silane crosslinking agents.

5. The coating with stealth, heat insulation, and heat protection functions according to claim 1, characterized in that, The catalyst is one or a combination of two or more of the following: organotin catalysts, guanidine hydroxyalkoxysilane catalysts, titanate catalysts, and titanate complex catalysts.

6. The coating with stealth, heat insulation, and heat protection functions according to claim 1, characterized in that, The diluent is one or a combination of two or more of the following: No. 120 solvent oil, ethyl acetate, and xylene.

7. The method for preparing the coating with stealth, heat insulation, and heat protection functions as described in any one of claims 1 to 6, characterized in that, The preparation method includes the following steps: (1) Silicone rubber, ablation-resistant filler, crosslinking agent, and some diluent are premixed and ground to disperse to obtain the first component; (2) The core-shell packing material, the dimensional packing material, the catalyst, and the remaining diluent are premixed and ground to disperse them, thus obtaining the second component; (3) Mix the first component and the second component evenly to obtain the coating that has the functions of stealth, heat insulation and heat protection.

8. The application of the coating with stealth, heat insulation and heat protection functions as described in any one of claims 1 to 6 in high-speed aircraft.

Images