Multi-layer composite structure heat-proof coating for heat-proof skirt and preparation method of multi-layer composite structure heat-proof coating

Abstract

The invention provides a multi-layer composite structure heat-proof coating for a heat-proof skirt and a preparation method of the multi-layer composite structure heat-proof coating. The multi-layer composite structure heat-proof coating comprises a base cloth layer, a base layer, a middle layer and a surface layer which are sequentially stacked, the base layer is prepared from the following raw materials: 100 parts of methyl vinyl silicone rubber, 20-55 parts of a first compound halogen-free flame retardant, 0.5-5 parts of a vulcanizing agent and 2-12 parts of a first heat-resistant modifier; the middle layer is prepared from the following raw materials in parts by weight: 95-105 parts of methyl vinyl silicone rubber, 65-100 parts of a second compound halogen-free flame retardant and 5-30 parts of a second heat-resistant modifier; the surface layer is prepared from the following raw materials in parts by weight: 5-20 parts of a third heat-resistant modifier, 0.5-3 parts of zirconium oxide and 2-9 parts of aluminum oxide. The heat-proof coating adopts a multi-layer composite structure design, the rubber proportion of the base layer is larger, basic flexibility and chemical stability are provided for the coating, the proportion of the compound halogen-free flame retardant of the middle layer is larger than that of the base layer, the flame retardance and the heat insulation performance are enhanced, and the radiation heat dissipation capacity can be improved through the surface anti-radiation coating.

Description

Technical Field

[0001] The present invention belongs to the technical field of aerospace engine heat-resistant skirts, and in particular relates to a multi-layer composite structure heat-resistant coating for heat-resistant skirts and a preparation method thereof. Background Art

[0002] Heat shields play a crucial role in aerospace engine protection. Heat shields are thermal insulation components surrounding the engine, designed to block high-temperature airflow and radiant heat, protecting surrounding engine structures from thermal damage. Currently, traditional heat shields are primarily made of carbon fiber composites. While these materials offer some heat resistance, they lack flexibility and are difficult to adapt to the dynamic deformation caused by engine swings. During actual engine operation, swings subject the heat shield to various forces, such as stretching and expansion. Due to the material's poor flexibility, it is prone to cracking and damage, thus compromising its protective effectiveness. Some flexible materials, such as conventional silicone rubber-coated fabrics, are available. For example, Chinese patent publication CN109719970B discloses a heat shield and its preparation method, which utilizes glass fiber prepreg coated with liquid silicone rubber. While offering good flexibility and adapting to dynamic deformation to a certain extent, these materials have low flame retardancy. In high-temperature gas environments, these materials easily burn or decompose, failing to provide effective engine protection and posing a serious threat to safe engine operation. Furthermore, some existing flame-retardant coatings utilize halogen-containing flame retardant systems, which release toxic gases upon combustion and fail to meet environmental standards. Furthermore, many coatings exhibit poor resistance to short-term, high-temperature ablation, struggling to maintain integrity for more than 30 seconds at a heat flux of 800 kW / ㎡. These technical bottlenecks and practical application barriers restrict the development of engine protection technology, necessitating an urgent need for a new technology to address these issues. Summary of the Invention

[0003] The technical problem solved by the present invention is to provide a multi-layer composite structure heat-proof coating for heat-proof skirts and a preparation method thereof. The multi-layer composite structure design is adopted, and the base layer adopts a silicone rubber coating with a larger proportion of rubber to provide basic flexibility and chemical stability for the coating. The proportion of halogen-free flame retardant in the middle layer is higher than that in the base layer to enhance the flame retardant and thermal insulation properties. The surface layer adopts an anti-radiation coating to improve the radiation heat dissipation capacity.

[0004] In order to solve the above problems, one aspect of the present invention provides a multi-layer composite structure heat-proof coating for heat-proof skirt, comprising a base fabric layer, a foundation layer, an intermediate layer and a surface layer stacked in sequence; The raw materials for preparing the base layer include the following components in parts by mass: 100 parts of methyl vinyl silicone rubber, 20-55 parts of a first compounded halogen-free flame retardant, 0.5-5 parts of a vulcanizing agent, and 2-12 parts of a first heat-resistant modifier; The raw materials for preparing the intermediate layer include the following components in parts by mass: 95-105 parts of methyl vinyl silicone rubber, 65-100 parts of the second compounded halogen-free flame retardant, and 5-30 parts of the second heat-resistant modifier; The raw materials for preparing the surface layer include the following components in parts by mass: 5 to 20 parts of a third heat-resistant modifier, 0.5 to 3 parts of zirconium oxide, and 2 to 9 parts of aluminum oxide.

[0005] Preferably, the raw materials for preparing the base layer include the following components in parts by mass: 100 parts of methyl vinyl silicone rubber, 30-50 parts of the first compounded halogen-free flame retardant, 1-3 parts of the vulcanizing agent, and 5-10 parts of the first heat-resistant modifier; The raw materials for preparing the intermediate layer include the following components in parts by mass: 95-105 parts of methyl vinyl silicone rubber, 70-90 parts of the second compounded halogen-free flame retardant, and 10-20 parts of the second heat-resistant modifier; The raw materials for preparing the surface layer include the following components in parts by mass: 10-15 parts of a third heat-resistant modifier, 1-2 parts of zirconium oxide, and 4-7 parts of aluminum oxide.

[0006] Preferably, the raw materials for preparing the base layer further include the following components in parts by mass: 15-25 parts of fumed silica and 5-15 parts of carbon fiber chopped fibers.

[0007] Preferably, the raw materials for preparing the first compound halogen-free flame retardant and / or the second compound halogen-free flame retardant include the following components in parts by mass: 25-40 parts of intumescent flame retardant, 5-10 parts of antimony trioxide, and 3-5 parts of nano-alumina; the intumescent flame retardant is one or a combination of ammonium polyphosphate and pentaerythritol.

[0008] Preferably, the vulcanizing agent is a platinum catalyst; the first heat-resistant modifier and / or the second heat-resistant modifier and / or the third heat-resistant modifier is a polyimide resin.

[0009] Preferably, the thickness of the base layer is 0.2-0.3 mm; the thickness of the intermediate layer is 0.3-0.5 mm; and the thickness of the surface layer is 0.1-0.2 mm.

[0010] Preferably, the upper surface of the surface layer is corrugated or wrinkled.

[0011] Another aspect of the present invention provides a method for preparing the multi-layer composite structure heat-resistant coating for the heat-resistant skirt, comprising the following steps: S1. The raw materials for preparing the base layer are mixed to obtain a base layer slurry, the base layer slurry is provided on the surface of the base fabric, and then high-temperature vulcanization is performed to form a base layer; S2. The raw materials for preparing the intermediate layer are mixed to obtain an intermediate layer slurry, and the intermediate layer slurry is disposed on the surface of the base layer to form an intermediate layer; S3. The surface preparation raw materials are mixed to obtain a surface slurry, and the surface slurry is provided on the surface of the intermediate layer to form a surface layer; S4. Pressing the obtained structure and then curing it to obtain the multi-layer composite structure heat-proof coating for the heat-proof skirt.

[0012] Preferably, before lamination, a corrugated PE film is placed on the upper surface of the surface layer, and after lamination, a corrugated shape is formed on the upper surface of the surface layer; or before lamination, a wrinkled PE film is placed on the upper surface of the surface layer, and after lamination, a wrinkled shape is formed on the upper surface of the surface layer.

[0013] Preferably, in step S1, the high-temperature vulcanization temperature is 150-180° C., and the time is 10 min.

[0014] Compared with the prior art, the present invention has the following beneficial effects: The heat-proof skirt of the present invention uses a multi-layer composite structure heat-proof coating, which adopts a multi-layer composite structure design. The base layer adopts a basic silicone rubber coating with a larger proportion of rubber to provide flexibility, which can better adapt to the dynamic deformation caused by the swing of the engine, avoid cracking due to excessive rigidity of the material, and ensure the integrity and protective performance of the heat-proof skirt in a dynamic environment. In order to solve the problem that some flexible materials have low flame retardancy, the middle layer of the multi-layer composite structure heat-proof coating adopts a flame-retardant silicone rubber matrix with a relatively large proportion of compounded halogen-free flame retardants, which enhances the flame retardant performance. Moreover, the proportion of flame retardant in the middle layer is higher than that in the base layer. Because the flame retardant is a powder, it can form a micro-nano pore structure, thereby enhancing the thermal insulation performance. In a high-temperature gas environment, it can effectively prevent the material from burning or decomposing, providing reliable protection for the engine. The existing halogen-containing flame retardant system will release toxic gases. The multi-layer composite structure heat-proof coating of the present invention adopts a halogen-free flame retardant system, which avoids the release of toxic gases during combustion, meets environmental protection requirements, and reduces harm to the environment and personnel. The zirconium oxide / aluminum oxide composite coating formed on the surface has radiation resistance and can improve the radiation heat dissipation capacity. Among them, the vulcanizing agent can promote the vulcanization reaction of the rubber, and the heat-resistant modifier can further improve the heat resistance of the coating. DETAILED DESCRIPTION

[0015] The following will clearly and completely describe the technical solutions of the present invention in conjunction with the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0016] One aspect of an embodiment of the present invention provides a multi-layer composite structure heat-resistant coating for a heat-resistant skirt, comprising a base fabric layer, a foundation layer, an intermediate layer, and a surface layer stacked in sequence; The raw materials for preparing the base layer include the following components in parts by mass: 100 parts of methyl vinyl silicone rubber, 20-55 parts of a first compounded halogen-free flame retardant, 0.5-5 parts of a vulcanizing agent, and 2-12 parts of a first heat-resistant modifier; The raw materials for preparing the intermediate layer include the following components in parts by mass: 95-105 parts of methyl vinyl silicone rubber, 65-100 parts of the second compounded halogen-free flame retardant, and 5-30 parts of the second heat-resistant modifier; The raw materials for preparing the surface layer include the following components in parts by mass: 5 to 20 parts of a third heat-resistant modifier, 0.5 to 3 parts of zirconium oxide, and 2 to 9 parts of aluminum oxide.

[0017] The heat-proof skirt of the embodiment of the present invention uses a multi-layer composite structure heat-proof coating, which adopts a multi-layer composite structure design. The base layer adopts a basic silicone rubber coating with a larger proportion of rubber to provide flexibility, which can better adapt to the dynamic deformation caused by the swing of the engine, avoid cracking due to excessive rigidity of the material, and ensure the integrity and protective performance of the heat-proof skirt in a dynamic environment. In order to solve the problem of low flame retardancy of some flexible materials, the middle layer of the multi-layer composite structure heat-proof coating adopts a flame-retardant silicone rubber matrix with a relatively large proportion of compounded halogen-free flame retardants, which enhances the flame retardancy. Moreover, the proportion of flame retardant in the middle layer is higher than that in the base layer. Because the flame retardant is a powder, it can form a micro-nano pore structure, thereby enhancing the thermal insulation performance. In a high-temperature gas environment, it can effectively prevent the material from burning or decomposing, providing reliable protection for the engine. The existing halogen-containing flame retardant system will release toxic gases. The multi-layer composite structure heat-proof coating of the present invention adopts a halogen-free flame retardant system to avoid the release of toxic gases during combustion, meet environmental protection requirements, and reduce harm to the environment and personnel. The zirconium oxide / aluminum oxide composite coating formed on the surface has radiation resistance and can improve the radiation heat dissipation capacity. Among them, the vulcanizing agent can promote the vulcanization reaction of the rubber, and the heat-resistant modifier can further improve the heat resistance of the coating.

[0018] Preferably, the raw materials for preparing the base layer include the following components in parts by mass: 100 parts of methyl vinyl silicone rubber, 30-50 parts of the first compounded halogen-free flame retardant, 1-3 parts of the vulcanizing agent, and 5-10 parts of the first heat-resistant modifier; The raw materials for preparing the intermediate layer include the following components in parts by mass: 95-105 parts of methyl vinyl silicone rubber, 70-90 parts of the second compounded halogen-free flame retardant, and 10-20 parts of the second heat-resistant modifier; The raw materials for preparing the surface layer include the following components in parts by mass: 10-15 parts of a third heat-resistant modifier, 1-2 parts of zirconium oxide, and 4-7 parts of aluminum oxide.

[0019] The multi-layer composite structure heat-proof coating for the heat-proof skirt of the present invention can be made to have more suitable flexibility, better flame retardant properties, better thermal insulation properties and ablation resistance by further optimizing the formula, so that the coating can maintain its integrity for ≥30 seconds under a heat flux of 800kw / ㎡, thereby improving the protective ability of the coating in extremely high temperature environments and ensuring the safe and stable operation of the engine.

[0020] Preferably, the vinyl content in the methyl vinyl silicone rubber is 0.15% to 0.3%.

[0021] Preferably, the raw materials for preparing the base layer further include the following components in parts by mass: 15-25 parts of fumed silica and 5-15 parts of carbon fiber chopped fibers.

[0022] The addition of fumed silica and carbon fiber chopped fibers can further improve the mechanical properties of the multi-layer composite structure heat-resistant coating.

[0023] Preferably, the raw materials for preparing the first compound halogen-free flame retardant and / or the second compound halogen-free flame retardant include the following components in parts by mass: 25-40 parts of intumescent flame retardant, 5-10 parts of antimony trioxide, and 3-5 parts of nano-alumina; the intumescent flame retardant is one or a combination of ammonium polyphosphate and pentaerythritol.

[0024] Intumescent flame retardants can expand at high temperatures to form a heat-insulating layer; antimony trioxide and nano-alumina are synergists that can further enhance the flame retardant effect and avoid the use of halogen-containing flame retardants.

[0025] Preferably, the vulcanizing agent is a platinum catalyst; the first heat-resistant modifier and / or the second heat-resistant modifier and / or the third heat-resistant modifier is a polyimide resin.

[0026] Preferably, the base layer has a thickness of 0.2-0.3 mm; the intermediate layer has a thickness of 0.3-0.5 mm; and the surface layer has a thickness of 0.1-0.2 mm. By further optimizing the thickness of each layer, the multi-layer composite heat-resistant coating for heat-resistant skirts of the present invention can achieve improved flexibility, flame retardancy, thermal insulation, and ablation resistance.

[0027] Preferably, the upper surface of the surface layer is corrugated or wrinkled. The corrugated or wrinkled upper surface allows the coating to maintain integrity during axial stretching and radial expansion, and adapt to deformation caused by engine swing.

[0028] Another aspect of an embodiment of the present invention provides a method for preparing the multi-layer composite structure heat-resistant coating for the heat-resistant skirt, comprising the following steps: S1. The raw materials for preparing the base layer are mixed to obtain a base layer slurry, the base layer slurry is provided on the surface of the base fabric, and then high-temperature vulcanization is performed to form a base layer; S2. The raw materials for preparing the intermediate layer are mixed to obtain an intermediate layer slurry, and the intermediate layer slurry is disposed on the surface of the base layer to form an intermediate layer; S3. The surface preparation raw materials are mixed to obtain a surface slurry, and the surface slurry is provided on the surface of the intermediate layer to form a surface layer; S4. Pressing the obtained structure and then curing it to obtain the multi-layer composite structure heat-proof coating for the heat-proof skirt.

[0029] Preferably, before lamination, a corrugated PE film is placed on the upper surface of the surface layer, and after lamination, a corrugated shape is formed on the upper surface of the surface layer; or before lamination, a wrinkled PE film is placed on the upper surface of the surface layer, and after lamination, a wrinkled shape is formed on the upper surface of the surface layer.

[0030] Preferably, in step S1, the high-temperature vulcanization temperature is 150-180° C., and the time is 10 min.

[0031] In the following examples, the platinum catalyst is the delayed-release platinum Ashby catalyst PT5000-VMC1000.

[0032] Example 1 The heat-resistant skirt of this embodiment uses a multi-layer composite structure heat-resistant coating, which includes a base fabric layer (alkali-free glass fiber cloth EW50), a foundation layer, an intermediate layer and a surface layer stacked in sequence; The base layer is made from the following components (by weight): 100 parts methyl vinyl silicone rubber (0.15% vinyl content), 30 parts first compound halogen-free flame retardant, 1 part platinum catalyst, 5 parts polyimide resin, 20 parts fumed silica, and 5 parts chopped carbon fiber. The first compound halogen-free flame retardant also contains the following components (by weight): 25 parts ammonium polyphosphate, 5 parts antimony trioxide, and 3 parts nano-alumina. The base layer is 0.2 mm thick.

[0033] The intermediate layer is made from the following components (by weight): 100 parts methyl vinyl silicone rubber (0.15% vinyl content), 80 parts a second compounded halogen-free flame retardant, and 10 parts polyimide resin. The second compounded halogen-free flame retardant also contains the following components (by weight): 25 parts ammonium polyphosphate, 5 parts antimony trioxide, and 3 parts nano-alumina. The intermediate layer is 0.3 mm thick.

[0034] The surface layer is prepared from raw materials comprising the following components by weight: 10 parts polyimide resin, 1 part zirconium oxide, and 4 parts aluminum oxide. The surface layer has a thickness of 0.1 mm and a corrugated upper surface.

[0035] The preparation method of the multilayer composite structure heat-resistant coating for the heat-resistant skirt of the present embodiment comprises the following steps: S1. The preparation raw materials of the base layer are mixed to obtain a base layer slurry, which is uniformly coated on the surface of the base fabric by the method of blade coating, and then vulcanized at 150°C for 10 minutes to form a base layer with a thickness of 0.2mm; S2. The preparation raw materials of the intermediate layer are mixed to obtain an intermediate layer slurry, which is uniformly coated on the surface of the base layer by the method of blade coating to form an intermediate layer with a thickness of 0.3mm; S3. The preparation raw materials of the surface layer are mixed to obtain a surface layer slurry, which is coated on the surface of the intermediate layer to form a surface layer with a thickness of 0.1mm; S4. A corrugated PE film is placed on the upper surface of the surface layer, and a pressure roller with a diameter greater than 330mm is used for pressing at room temperature with a pressure of 0.3MPa. After pressing, the sample is placed at room temperature for not less than 24 hours for curing. After curing, the PE film is removed to obtain a multilayer composite structure heat-resistant coating for the heat-resistant skirt.

[0036] Example 2 The multilayer composite structure heat-resistant coating of the present embodiment comprises a base fabric layer (alkali-free glass fiber cloth EW50), a base layer, an intermediate layer and a surface layer which are sequentially stacked; The preparation raw materials of the base layer comprise the following components in mass fraction: methyl vinyl silicone rubber (vinyl content 0.2%) 100 parts, first compounded halogen-free flame retardant 40 parts, platinum catalyst 2 parts, polyimide resin 7 parts, fumed white carbon black 25 parts, and carbon fiber chopped fiber 10 parts. The preparation raw materials of the first compounded halogen-free flame retardant comprise the following components in mass fraction: ammonium polyphosphate 30 parts, antimony trioxide 7 parts, and nano-alumina 4 parts. The thickness of the base layer is 0.25mm.

[0037] The preparation raw materials of the intermediate layer comprise the following components in mass fraction: methyl vinyl silicone rubber (vinyl content 0.15%) 100 parts, second compounded halogen-free flame retardant 80 parts, and polyimide resin 10 parts. The preparation raw materials of the second compounded halogen-free flame retardant comprise the following components in mass fraction: ammonium polyphosphate 25 parts, antimony trioxide 5 parts, and nano-alumina 3 parts. The thickness of the intermediate layer is 0.4mm.

[0038] The preparation raw materials of the surface layer comprise the following components in mass fraction: polyimide resin 10 parts, zirconium oxide 1 part, and aluminum oxide 4 parts. The thickness of the surface layer is 0.15mm. The upper surface of the surface layer is corrugated.

[0039] The preparation method of the multilayer composite structure heat-resistant coating for the heat-resistant skirt of the present embodiment is the same as that of Example 1.

[0040] Example 3 The heat-resistant skirt of this embodiment uses a multi-layer composite structure heat-resistant coating, which includes a base fabric layer (alkali-free glass fiber cloth EW50), a foundation layer, an intermediate layer and a surface layer stacked in sequence; The base layer is made from the following components (by weight): 100 parts methyl vinyl silicone rubber (0.3% vinyl content), 50 parts first compound halogen-free flame retardant, 3 parts platinum catalyst, 10 parts polyimide resin, 15 parts fumed silica, and 15 parts chopped carbon fiber. The first compound halogen-free flame retardant also contains the following components (by weight): 40 parts ammonium polyphosphate, 10 parts antimony trioxide, and 5 parts nano-alumina. The base layer is 0.3 mm thick.

[0041] The intermediate layer is made from the following components (by weight): 100 parts methyl vinyl silicone rubber (0.15% vinyl content), 80 parts a second compounded halogen-free flame retardant, and 10 parts polyimide resin. The second compounded halogen-free flame retardant is made from the following components (by weight): 25 parts ammonium polyphosphate, 5 parts antimony trioxide, and 3 parts nano-alumina. The intermediate layer is 0.5 mm thick.

[0042] The surface layer is prepared from raw materials comprising the following components by weight: 10 parts polyimide resin, 1 part zirconium oxide, and 4 parts aluminum oxide. The surface layer has a thickness of 0.2 mm and a corrugated upper surface.

[0043] The preparation method of the multi-layer composite structure heat-resistant coating for the heat-resistant skirt of this embodiment is the same as that of Example 1.

[0044] Example 4 The heat-resistant skirt of this embodiment uses a multi-layer composite structure heat-resistant coating, which includes a base fabric layer (alkali-free glass fiber cloth EW50), a foundation layer, an intermediate layer and a surface layer stacked in sequence; In this embodiment, the raw material composition and proportions for the base layer and surface layer are the same as in Example 2, and the thicknesses of the base layer and surface layer are the same as in Example 2. The only difference is the raw material used to prepare the intermediate layer. The intermediate layer comprises the following components in parts by weight: 100 parts methyl vinyl silicone rubber (0.15% vinyl content), 70 parts of a second compounded halogen-free flame retardant, and 15 parts of a polyimide resin. The raw materials used to prepare the second compounded halogen-free flame retardant comprise the following components in parts by weight: 30 parts ammonium polyphosphate, 10 parts antimony trioxide, and 5 parts nano-alumina. The thickness of the intermediate layer is 0.4 mm.

[0045] The preparation method of the multi-layer composite structure heat-resistant coating for the heat-resistant skirt of this embodiment is the same as that of Example 1.

[0046] Example 5 The heat-resistant skirt of this embodiment uses a multi-layer composite structure heat-resistant coating, which includes a base fabric layer (alkali-free glass fiber cloth EW50), a foundation layer, an intermediate layer and a surface layer stacked in sequence; In this embodiment, the raw material composition and proportions for the base layer and surface layer are the same as in Example 2, and the thicknesses of the base layer and surface layer are the same as in Example 2. The only difference is the raw material used to prepare the intermediate layer. The intermediate layer comprises the following components in parts by weight: 100 parts methyl vinyl silicone rubber (0.15% vinyl content), 90 parts second compounded halogen-free flame retardant, and 20 parts polyimide resin. The raw materials used to prepare the second compounded halogen-free flame retardant comprise the following components in parts by weight: 40 parts ammonium polyphosphate, 10 parts antimony trioxide, and 3 parts nano-alumina. The thickness of the intermediate layer is 0.4 mm.

[0047] The preparation method of the multi-layer composite structure heat-resistant coating for the heat-resistant skirt of this embodiment is the same as that of Example 1.

[0048] Example 6 The heat-resistant skirt of this embodiment uses a multi-layer composite structure heat-resistant coating, which includes a base fabric layer (alkali-free glass fiber cloth EW50), a foundation layer, an intermediate layer and a surface layer stacked in sequence; In this embodiment, the raw material compositions and quantities of the base layer and intermediate layer are the same as in Example 2, and the thicknesses of the base layer and intermediate layer are the same as in Example 2. The difference lies in the raw materials used to prepare the surface layer. The surface layer comprises the following components by weight: 15 parts polyimide resin, 2 parts zirconium oxide, and 7 parts aluminum oxide. The thickness of the surface layer is 0.15 mm. The upper surface of the surface layer is corrugated.

[0049] The preparation method of the multi-layer composite structure heat-resistant coating for the heat-resistant skirt of this embodiment is the same as that of Example 1.

[0050] Example 7 The heat-resistant skirt of this embodiment uses a multi-layer composite structure heat-resistant coating, which includes a base fabric layer (alkali-free glass fiber cloth EW50), a foundation layer, an intermediate layer and a surface layer stacked in sequence; In this embodiment, the raw material composition and the number of parts of each layer are the same as those in Example 2, except that the thickness of each layer is different from that in Example 2. In this embodiment, the base layer is 0.2 mm thick, the middle layer is 0.5 mm thick, and the surface layer is 0.1 mm thick.

[0051] The preparation method of the multi-layer composite structure heat-resistant coating for the heat-resistant skirt of this embodiment is the same as that of Example 1.

[0052] Example 8 The heat-resistant skirt of this embodiment uses a multi-layer composite structure heat-resistant coating, which includes a base fabric layer (alkali-free glass fiber cloth EW50), a foundation layer, an intermediate layer and a surface layer stacked in sequence; In this embodiment, the raw material composition and the number of parts of each layer are the same as those in Example 2, except that the thickness of each layer is different from that in Example 2. In this embodiment, the thickness of the base layer is 0.3 mm, the thickness of the middle layer is 0.3 mm, and the thickness of the surface layer is 0.2 mm.

[0053] The preparation method of the multi-layer composite structure heat-resistant coating for the heat-resistant skirt of this embodiment is the same as that of Example 1.

[0054] Example 9 The heat-resistant skirt of this embodiment uses a multi-layer composite structure heat-resistant coating, which includes a base fabric layer (alkali-free glass fiber cloth EW50), a foundation layer, an intermediate layer and a surface layer stacked in sequence; In this embodiment, the raw material composition and the number of parts of each layer are the same as those in Example 2, except that the thickness of each layer is different from that in Example 2. In this embodiment, the base layer is 0.1 mm thick, the middle layer is 0.6 mm thick, and the surface layer is 0.25 mm thick.

[0055] The preparation method of the multi-layer composite structure heat-resistant coating for the heat-resistant skirt of this embodiment is the same as that of Example 1.

[0056] Example 10 The heat-resistant skirt of this embodiment uses a multi-layer composite structure heat-resistant coating, which includes a base fabric layer (alkali-free glass fiber cloth EW50), a foundation layer, an intermediate layer and a surface layer stacked in sequence; In this embodiment, the raw material composition and number of each layer are the same as those in Example 2, except that the thickness of each layer is different from that in Example 2. In this embodiment, the base layer is 0.4 mm thick, the middle layer is 0.2 mm thick, and the surface layer is 0.05 mm thick.

[0057] The preparation method of the multi-layer composite structure heat-resistant coating for the heat-resistant skirt of this embodiment is the same as that of Example 1.

[0058] Example 11 The heat-resistant skirt of this embodiment uses a multi-layer composite structure heat-resistant coating, which includes a base fabric layer (alkali-free glass fiber cloth EW50), a foundation layer, an intermediate layer and a surface layer stacked in sequence; In this embodiment, the raw material composition and quantity of the intermediate layer and the surface layer are the same as those in Example 2, and the thickness of the intermediate layer and the surface layer is the same as that in Example 2. The difference is that the raw materials for the base layer are different. The raw materials for the base layer include the following components in parts by weight: 100 parts of methyl vinyl silicone rubber (vinyl content 0.2%), 20 parts of a first compounded halogen-free flame retardant, 5 parts of a platinum catalyst, 2 parts of a polyimide resin, 25 parts of fumed silica, and 10 parts of chopped carbon fiber. Among them, the raw materials for the first compounded halogen-free flame retardant include the following components in parts by weight: 30 parts of ammonium polyphosphate, 7 parts of antimony trioxide, and 4 parts of nano-alumina. The thickness of the base layer is 0.25 mm.

[0059] The preparation method of the multi-layer composite structure heat-resistant coating for the heat-resistant skirt of this embodiment is the same as that of Example 1.

[0060] Example 12 The heat-resistant skirt of this embodiment uses a multi-layer composite structure heat-resistant coating, which includes a base fabric layer (alkali-free glass fiber cloth EW50), a foundation layer, an intermediate layer and a surface layer stacked in sequence; In this embodiment, the raw material composition and quantity of the intermediate layer and the surface layer are the same as those in Example 2, and the thickness of the intermediate layer and the surface layer is the same as that in Example 2. The difference is that the raw materials for the base layer are different. The raw materials for the base layer include the following components in parts by mass: 100 parts of methyl vinyl silicone rubber (vinyl content 0.2%), 55 parts of a first compounded halogen-free flame retardant, 0.5 parts of a platinum catalyst, 12 parts of a polyimide resin, 25 parts of fumed silica, and 10 parts of chopped carbon fiber. Among them, the raw materials for the first compounded halogen-free flame retardant include the following components in parts by mass: 30 parts of ammonium polyphosphate, 7 parts of antimony trioxide, and 4 parts of nano-alumina. The thickness of the base layer is 0.25 mm.

[0061] The preparation method of the multi-layer composite structure heat-resistant coating for the heat-resistant skirt of this embodiment is the same as that of Example 1.

[0062] Example 13 The heat-resistant skirt of this embodiment uses a multi-layer composite structure heat-resistant coating, which includes a base fabric layer (alkali-free glass fiber cloth EW50), a foundation layer, an intermediate layer and a surface layer stacked in sequence; In this embodiment, the raw material composition and quantity of the intermediate layer and the surface layer are the same as those in Example 2, and the thickness of the intermediate layer and the surface layer is the same as that in Example 2. The difference is that the raw materials for the base layer are different. The raw materials for the base layer include the following components in parts by mass: 100 parts of methyl vinyl silicone rubber (vinyl content 0.2%), 30 parts of a first compounded halogen-free flame retardant, 1 part of a platinum catalyst, 5 parts of a polyimide resin, 25 parts of fumed silica, and 10 parts of chopped carbon fiber. Among them, the raw materials for the first compounded halogen-free flame retardant include the following components in parts by mass: 30 parts of ammonium polyphosphate, 7 parts of antimony trioxide, and 4 parts of nano-alumina. The thickness of the base layer is 0.25 mm.

[0063] The preparation method of the multi-layer composite structure heat-resistant coating for the heat-resistant skirt of this embodiment is the same as that of Example 1.

[0064] Example 14 The heat-resistant skirt of this embodiment uses a multi-layer composite structure heat-resistant coating, which includes a base fabric layer (alkali-free glass fiber cloth EW50), a foundation layer, an intermediate layer and a surface layer stacked in sequence; In this embodiment, the raw material composition and quantity of the intermediate layer and the surface layer are the same as those in Example 2, and the thickness of the intermediate layer and the surface layer is the same as that in Example 2. The difference is that the raw materials for the base layer are different. The raw materials for the base layer include the following components in parts by weight: 100 parts of methyl vinyl silicone rubber (vinyl content 0.2%), 50 parts of a first compounded halogen-free flame retardant, 3 parts of a platinum catalyst, 10 parts of a polyimide resin, 25 parts of fumed silica, and 10 parts of chopped carbon fiber. Among them, the raw materials for the first compounded halogen-free flame retardant include the following components in parts by weight: 30 parts of ammonium polyphosphate, 7 parts of antimony trioxide, and 4 parts of nano-alumina. The thickness of the base layer is 0.25 mm.

[0065] The preparation method of the multi-layer composite structure heat-resistant coating for the heat-resistant skirt of this embodiment is the same as that of Example 1.

[0066] Example 15 The heat-resistant skirt of this embodiment uses a multi-layer composite structure heat-resistant coating, which includes a base fabric layer (alkali-free glass fiber cloth EW50), a foundation layer, an intermediate layer and a surface layer stacked in sequence; In this embodiment, the raw material composition and proportions for the base layer and surface layer are the same as in Example 2, and the thicknesses of the base layer and surface layer are the same as in Example 2. The only difference is the raw material used to prepare the intermediate layer. The intermediate layer comprises the following components in parts by weight: 95 parts methyl vinyl silicone rubber (0.15% vinyl content), 100 parts of a second compounded halogen-free flame retardant, and 30 parts of a polyimide resin. The raw materials used to prepare the second compounded halogen-free flame retardant comprise the following components in parts by weight: 25 parts ammonium polyphosphate, 5 parts antimony trioxide, and 3 parts nano-alumina. The thickness of the intermediate layer is 0.4 mm.

[0067] The preparation method of the multi-layer composite structure heat-resistant coating for the heat-resistant skirt of this embodiment is the same as that of Example 1.

[0068] Example 16 The heat-resistant skirt of this embodiment uses a multi-layer composite structure heat-resistant coating, which includes a base fabric layer (alkali-free glass fiber cloth EW50), a foundation layer, an intermediate layer and a surface layer stacked in sequence; In this embodiment, the raw material composition and proportions for the base layer and surface layer are the same as in Example 2, and the thicknesses of the base layer and surface layer are the same as in Example 2. The only difference is the raw materials for the intermediate layer. The intermediate layer comprises the following components in parts by weight: 105 parts methyl vinyl silicone rubber (0.15% vinyl content), 65 parts a second compounded halogen-free flame retardant, and 5 parts a polyimide resin. The raw materials for the second compounded halogen-free flame retardant comprise the following components in parts by weight: 25 parts ammonium polyphosphate, 5 parts antimony trioxide, and 3 parts nano-alumina. The thickness of the intermediate layer is 0.4 mm.

[0069] The preparation method of the multi-layer composite structure heat-resistant coating for the heat-resistant skirt of this embodiment is the same as that of Example 1.

[0070] Example 17 The heat-resistant skirt of this embodiment uses a multi-layer composite structure heat-resistant coating, which includes a base fabric layer (alkali-free glass fiber cloth EW50), a foundation layer, an intermediate layer and a surface layer stacked in sequence; In this embodiment, the raw material composition and proportions for the base layer and surface layer are the same as in Example 2, and the thicknesses of the base layer and surface layer are the same as in Example 2. The only difference is the raw materials for the intermediate layer. The intermediate layer comprises the following components in parts by weight: 95 parts methyl vinyl silicone rubber (0.15% vinyl content), 70 parts a second compounded halogen-free flame retardant, and 20 parts a polyimide resin. The raw materials for the second compounded halogen-free flame retardant comprise the following components in parts by weight: 25 parts ammonium polyphosphate, 5 parts antimony trioxide, and 3 parts nano-alumina. The thickness of the intermediate layer is 0.4 mm.

[0071] The preparation method of the multi-layer composite structure heat-resistant coating for the heat-resistant skirt of this embodiment is the same as that of Example 1.

[0072] Example 18 The heat-resistant skirt of this embodiment uses a multi-layer composite structure heat-resistant coating, which includes a base fabric layer (alkali-free glass fiber cloth EW50), a foundation layer, an intermediate layer and a surface layer stacked in sequence; In this embodiment, the raw material composition and proportions for the base layer and surface layer are the same as in Example 2, and the thicknesses of the base layer and surface layer are the same as in Example 2. The only difference is the raw materials for the intermediate layer. The intermediate layer comprises the following components in parts by weight: 105 parts methyl vinyl silicone rubber (0.15% vinyl content), 90 parts second compounded halogen-free flame retardant, and 10 parts polyimide resin. The raw materials for the second compounded halogen-free flame retardant comprise the following components in parts by weight: 25 parts ammonium polyphosphate, 5 parts antimony trioxide, and 3 parts nano-alumina. The thickness of the intermediate layer is 0.4 mm.

[0073] The preparation method of the multi-layer composite structure heat-resistant coating for the heat-resistant skirt of this embodiment is the same as that of Example 1.

[0074] Comparative Example 1 The heat-proof skirt of this comparative example uses a multi-layer composite structure heat-proof coating, including a base fabric layer (alkali-free glass fiber cloth EW50), a foundation layer, an intermediate layer and a surface layer stacked in sequence; In this comparative example, the composition and number of raw materials for the preparation of the intermediate layer and the surface layer are the same as those in Example 2, and the thickness of the intermediate layer and the surface layer are the same as those in Example 2. The difference is that the raw materials for the preparation of the base layer are different. The raw materials for the preparation of the base layer include the following components in parts by mass: 100 parts of methyl vinyl silicone rubber (vinyl content 0.2%), 15 parts of the first compound halogen-free flame retardant, 6 parts of platinum catalyst, 1 part of polyimide resin, 25 parts of fumed silica, and 10 parts of carbon fiber chopped fibers. Among them, the raw materials for the preparation of the first compound halogen-free flame retardant include the following components in parts by mass: 30 parts of ammonium polyphosphate, 7 parts of antimony trioxide, and 4 parts of nano-alumina. The thickness of the base layer is 0.25 mm.

[0075] The preparation method of the multi-layer composite structure heat-resistant coating for the heat-resistant skirt of this comparative example is the same as that of Example 1.

[0076] Comparative Example 2 The heat-proof skirt of this comparative example uses a multi-layer composite structure heat-proof coating, including a base fabric layer (alkali-free glass fiber cloth EW50), a foundation layer, an intermediate layer and a surface layer stacked in sequence; In this comparative example, the composition and number of raw materials for the preparation of the intermediate layer and the surface layer are the same as those in Example 2, and the thickness of the intermediate layer and the surface layer are the same as those in Example 2. The difference is that the raw materials for the preparation of the base layer are different. The raw materials for the preparation of the base layer include the following components in parts by mass: 100 parts of methyl vinyl silicone rubber (vinyl content 0.2%), 60 parts of the first compound halogen-free flame retardant, 0.3 parts of platinum catalyst, 15 parts of polyimide resin, 25 parts of fumed silica, and 10 parts of carbon fiber chopped fibers. Among them, the raw materials for the preparation of the first compound halogen-free flame retardant include the following components in parts by mass: 30 parts of ammonium polyphosphate, 7 parts of antimony trioxide, and 4 parts of nano-alumina. The thickness of the base layer is 0.25 mm.

[0077] The preparation method of the multi-layer composite structure heat-resistant coating for the heat-resistant skirt of this comparative example is the same as that of Example 1.

[0078] Comparative Example 3 The heat-proof skirt of this comparative example uses a multi-layer composite structure heat-proof coating, including a base fabric layer (alkali-free glass fiber cloth EW50), a foundation layer, an intermediate layer and a surface layer stacked in sequence; In this comparative example, the raw material composition and quantity for the base layer and surface layer were the same as in Example 2, and the thickness of the base layer and surface layer was the same as in Example 2. The only difference was the raw material for the intermediate layer. The intermediate layer comprised the following components in parts by weight: 90 parts methyl vinyl silicone rubber (0.15% vinyl content), 110 parts of a second compounded halogen-free flame retardant, and 35 parts of a polyimide resin. The raw materials for the second compounded halogen-free flame retardant comprised the following components in parts by weight: 25 parts ammonium polyphosphate, 5 parts antimony trioxide, and 3 parts nano-alumina. The thickness of the intermediate layer was 0.4 mm.

[0079] The preparation method of the multi-layer composite structure heat-resistant coating for the heat-resistant skirt of this comparative example is the same as that of Example 1.

[0080] Comparative Example 4 The heat-proof skirt of this comparative example uses a multi-layer composite structure heat-proof coating, including a base fabric layer (alkali-free glass fiber cloth EW50), a foundation layer, an intermediate layer and a surface layer stacked in sequence; In this comparative example, the raw material compositions and quantities for the base layer and surface layer were the same as in Example 2, and the thicknesses of the base layer and surface layer were the same as in Example 2. The only difference was the raw materials used to prepare the intermediate layer. The intermediate layer's raw materials included the following components in parts by weight: 110 parts methyl vinyl silicone rubber (0.15% vinyl content), 60 parts of a second compounded halogen-free flame retardant, and 3 parts of a polyimide resin. The raw materials used to prepare the second compounded halogen-free flame retardant included the following components in parts by weight: 25 parts ammonium polyphosphate, 5 parts antimony trioxide, and 3 parts nano-alumina. The thickness of the intermediate layer was 0.4 mm.

[0081] The preparation method of the multi-layer composite structure heat-resistant coating for the heat-resistant skirt of this comparative example is the same as that of Example 1.

[0082] The flexibility, flame retardancy, thermal insulation performance and mechanical properties of the multi-layer composite structure thermal insulation coating for the thermal skirt of the above embodiments and comparative examples were tested, and the test results are shown in Table 1. The experimental conditions for the thermal insulation performance test are: 1) heat flux 700KW / m 2 Ablation time 40s, heat flux 200KW / m 2 Ablation time 126s, test the final temperature of the thermal protection coating back temperature. 2) Heat flux 300KW / m 2 The ablation time is 160s, and the final temperature of the back surface of the thermal protection coating is tested.

[0083] As can be seen from the data in Table 1, the multi-layer composite heat-resistant coatings for heat-resistant skirts in each embodiment of this application all exhibit excellent flexibility, flame retardancy, thermal insulation, and mechanical properties. The difference between Comparative Examples 1 and 2 and Example 2 is that the base layers are prepared using different raw materials. The proportions of the components in the base layers in Comparative Examples 1 and 2 are inappropriate, resulting in poor overall performance of the resulting heat-resistant coatings. In Comparative Examples 3 and 4, the proportions of the components in the intermediate layers are inappropriate, resulting in poor overall performance of the resulting heat-resistant coatings.

[0084] Compared with Examples 2, 7-10, the difference is that the thickness of each layer is different. Among them, the thickness of each layer of Examples 2, 7, and 8 is more appropriate, and the comprehensive performance of the obtained heat-resistant coating is better than that of Examples 9 and 10.

[0085] Compared with Examples 2, 11-14, the difference is that the raw materials for preparing the base layer are different. Among them, the proportion of raw materials for preparing Examples 2, 13, and 14 is more appropriate, and the comprehensive performance of the obtained heat-resistant coating is better than that of Examples 11 and 12.

[0086] Compared with Examples 2, 15-18, the difference is that the raw materials for preparing the intermediate layer are different. Among them, the proportion of raw materials for preparing Examples 2, 17 and 18 is more appropriate, and the comprehensive performance of the obtained heat-resistant coating is better than that of Examples 15 and 16.

[0087] Table 1

[0088] Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will readily appreciate that other variations or modifications based on the above descriptions are possible. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

Claims

1. A multi-layer composite structure heat-resistant coating for heat-resistant skirt, characterized by: It includes a base fabric layer, a foundation layer, an intermediate layer and a surface layer stacked in sequence; The raw materials for preparing the base layer include the following components in parts by mass: 100 parts of methyl vinyl silicone rubber, 20-55 parts of a first compounded halogen-free flame retardant, 0.5-5 parts of a vulcanizing agent, and 2-12 parts of a first heat-resistant modifier; The raw materials for preparing the intermediate layer include the following components in parts by mass: 95-105 parts of methyl vinyl silicone rubber, 65-100 parts of the second compounded halogen-free flame retardant, and 5-30 parts of the second heat-resistant modifier; The raw materials for preparing the surface layer include the following components in parts by mass: 5 to 20 parts of a third heat-resistant modifier, 0.5 to 3 parts of zirconium oxide, and 2 to 9 parts of aluminum oxide.

2. The multi-layer composite structure heat-resistant coating for heat-resistant skirt according to claim 1, characterized in that: The raw materials for preparing the base layer include the following components in parts by mass: 100 parts of methyl vinyl silicone rubber, 30-50 parts of a first compounded halogen-free flame retardant, 1-3 parts of a vulcanizing agent, and 5-10 parts of a first heat-resistant modifier; The raw materials for preparing the intermediate layer include the following components in parts by mass: 95-105 parts of methyl vinyl silicone rubber, 70-90 parts of the second compounded halogen-free flame retardant, and 10-20 parts of the second heat-resistant modifier; The raw materials for preparing the surface layer include the following components in parts by mass: 10-15 parts of a third heat-resistant modifier, 1-2 parts of zirconium oxide, and 4-7 parts of aluminum oxide.

3. The multi-layer composite structure heat-resistant coating for heat-resistant skirt according to claim 2, characterized in that: The raw materials for preparing the base layer further include the following components in parts by mass: 15 to 25 parts of fumed silica and 5 to 15 parts of carbon fiber chopped fibers.

4. The multi-layer composite structure heat-resistant coating for heat-resistant skirt according to claim 3, characterized in that: The raw materials for preparing the first compound halogen-free flame retardant and / or the second compound halogen-free flame retardant include the following components in parts by mass: 25-40 parts of intumescent flame retardant, 5-10 parts of antimony trioxide, and 3-5 parts of nano-alumina; the intumescent flame retardant is one or a combination of ammonium polyphosphate and pentaerythritol.

5. The multi-layer composite structure heat-resistant coating for heat-resistant skirt according to claim 1, characterized in that: The vulcanizing agent is a platinum catalyst; the first heat-resistant modifier and / or the second heat-resistant modifier and / or the third heat-resistant modifier is a polyimide resin.

6. The multi-layer composite structure heat-resistant coating for heat-resistant skirt according to claim 1, characterized in that: The thickness of the base layer is 0.2-0.3 mm; the thickness of the intermediate layer is 0.3-0.5 mm; and the thickness of the surface layer is 0.1-0.2 mm.

7. The multi-layer composite structure heat-resistant coating for heat-resistant skirt according to claim 1, characterized in that: The upper surface of the surface layer is corrugated or wrinkled.

8. A method for preparing a multi-layer composite structure heat-resistant coating for a heat-resistant skirt according to any one of claims 1 to 7, characterized in that: The following steps are involved: S1. The raw materials for preparing the base layer are mixed to obtain a base layer slurry, the base layer slurry is provided on the surface of the base fabric, and then high-temperature vulcanization is performed to form a base layer; S2. The raw materials for preparing the intermediate layer are mixed to obtain an intermediate layer slurry, and the intermediate layer slurry is disposed on the surface of the base layer to form an intermediate layer; S3. The surface preparation raw materials are mixed to obtain a surface slurry, and the surface slurry is provided on the surface of the intermediate layer to form a surface layer; S4. Pressing the obtained structure and then curing it to obtain the multi-layer composite structure heat-proof coating for the heat-proof skirt.

9. The preparation method according to claim 8, characterized in that: Before lamination, a corrugated PE film is placed on the upper surface of the surface layer, and after lamination, a corrugated shape is formed on the upper surface of the surface layer; or before lamination, a wrinkled PE film is placed on the upper surface of the surface layer, and after lamination, a wrinkled shape is formed on the upper surface of the surface layer.

10. The preparation method according to claim 8, characterized in that: In step S1, the high temperature vulcanization temperature is 150-180° C. and the time is 10 min.

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