Ablation and heat insulation function partitioned integrated heat protection structure and preparation method thereof

Abstract

The application provides an ablation and thermal insulation function partitioned overall heat protection structure and a preparation method thereof. The preparation method comprises the following steps: S1, short-cut fiber premix of an ablation layer is loaded into a negative mold mold, and molding preforming curing is performed to obtain an ablation layer preform; S2, an inner profile of the ablation layer preform is mechanically processed; S3, low-density prepreg of a thermal insulation layer is laid on the inner profile; S4, molding preforming curing is performed to obtain a thermal insulation layer-ablation layer preform; S5, the inner profile of the thermal insulation layer is mechanically processed; and S6, demolding is performed to obtain the ablation and thermal insulation function partitioned overall heat protection structure. The preparation method adopts short-cut fiber premix to prepare the ablation layer on the outside, and the ablation layer can meet the temperature resistance requirement; the low-density prepreg is adopted to prepare the thermal insulation layer on the inside, and the thermal insulation layer can meet the load bearing structure and the working temperature requirement of the equipment in the cabin, and the light weight requirement of the heat protection structure is met.

Description

Technical Field

[0001] This invention belongs to the field of heat protection structure technology for high-speed aircraft, specifically relating to an integrated heat protection structure with ablation and heat insulation functional zones and its preparation method. Background Technology

[0002] In the field of high-speed aircraft technology, based on aerodynamics, the operating environment temperature can reach tens of thousands of degrees Celsius. Currently, no single material can withstand such high temperatures. Therefore, high-speed aircraft use a certain thickness of polymer composite material for ablation thermal protection on the equipment periphery.

[0003] Equipment in a certain engineering field encountered an external operating temperature of nearly 2000℃ and a long-term operating temperature of over 1000℃. However, the operating temperature of its load-bearing structure was required to be less than 200℃, and the operating temperature of the internal equipment was required to be less than 60℃. Moreover, the outer ablation layer needed to be integrated with other components. Therefore, the external shape of the thermal protection structure was required to be irregular.

[0004] For the design of high-speed aircraft, weight is a crucial indicator of its advanced nature, and lightweighting is a significant development direction in this field. Currently, the thermal protection layers of high-speed aircraft often employ single-layer composite ablation structures. For example, Chinese patent document CN 111114750A discloses a thermal protection device and a reentry vehicle. The thermal protection device includes a rigid or flexible heat insulation layer made of fibers; a heat-resistant cover is connected to one side of the heat insulation layer. The composite material of this aircraft's heat insulation layer can withstand high temperatures of 1760℃, and the supporting structure can withstand temperature and stress conditions of 1350–1600℃. However, to ensure the normal operation of engineering equipment under conditions where the external operating temperature is nearly 2000℃, the long-term operating temperature is above 1000℃, the operating temperature of its load-bearing structure is less than 200℃, and the operating temperature of the internal equipment is less than 60℃, the traditional single-layer composite ablation structure, while meeting the functional requirements of ablation resistance and heat insulation, cannot meet the weight requirements.

[0005] Therefore, how to manufacture a heat-resistant structure for high-speed aircraft to meet the temperature tolerance requirements of the aircraft, the operating temperature requirements of the load-bearing structure and the internal equipment, and the lightweight requirements of high-speed aircraft, while also achieving an irregularly shaped design for the thermal protection structure, is a problem that needs to be solved. Summary of the Invention

[0006] The technical problem solved by this invention is that the current heat protection structure of high-speed aircraft is difficult to simultaneously meet the requirements of temperature resistance, load-bearing structure, internal equipment operating temperature, and aircraft lightweighting. To address this, an integrated heat protection structure with ablation and heat insulation functional zones and its preparation method are provided. An ablation layer is prepared on the outside using ablation-resistant chopped fiber premix, which can meet the temperature resistance requirements. An internal heat insulation layer is prepared using low-density prepreg, which can meet the requirements of load-bearing structure, internal equipment operating temperature, and lightweighting of heat protection structure. The outer ablation layer is pre-filled with chopped fiber premix in a negative mold and pre-cured, which can realize the special irregular structure design of the outer ablation-resistant layer.

[0007] To address the above problems, a first aspect of the present invention provides a method for preparing an integral heat-resistant structure with ablation and heat insulation functional zones, comprising the following steps:

[0008] S1. The ablation layer chopped fiber premix is ​​loaded into the female mold and subjected to the first molding preforming and curing to obtain the ablation layer preform;

[0009] S2. Perform the first machining on the inner surface of the ablation layer preform;

[0010] S3. Lay the low-density prepreg of the heat insulation layer onto the inner surface of the ablation layer preform after the first mechanical processing to obtain the heat insulation layer paving sheet-ablation layer preform assembly;

[0011] S4. Perform a second molding preforming and curing on the heat insulation layer-ablation layer preform assembly to obtain the heat insulation layer-ablation layer preform.

[0012] S5. Perform a second machining operation on the inner surface of the insulation layer of the insulation layer-ablation layer preform;

[0013] S6. Demold the preform of the heat insulation layer-ablation layer to obtain the overall heat-proof structure of the ablation and heat insulation functional zones.

[0014] Preferably, step S1 specifically includes the following steps:

[0015] S101. The ablation layer chopped fiber premix is ​​loaded into a premix preforming container to prepare an ablation layer premix filling block;

[0016] S102. The ablation layer premix filling block is filled into the female mold, and the ablation layer premix filling block is packaged with a molding sleeve to obtain the ablation layer premix filling block-female mold packaging assembly;

[0017] S103. Vacuum the ablation layer premix filling block-vacuum mold packaging assembly;

[0018] S104. The ablation layer premix filling block-vacuum mold packaging assembly is subjected to a first molding preforming and curing to obtain the ablation layer preform.

[0019] Preferably, step S101 specifically includes the following steps: loading the ablation layer chopped fiber premix into a premix preforming container, drying it at room temperature for 24-28 hours, and then vacuum-preserving it for 1-2 hours to obtain the ablation layer premix filling block.

[0020] Preferably, in step S102, after the ablation layer premix filling block is filled into the female mold, it is vacuumed and shaped for 1-2 hours.

[0021] Preferably, step S103 specifically includes the following steps:

[0022] The ablation layer premix filling block-vacuum mold packaging assembly is stored at 90°C and below -0.08MPa for 3-4 hours.

[0023] Preferably, in step S1, the curing conditions during the first molding preforming curing are as follows: pressurize to 3.7-4 MPa at a rate of 1 MPa / 10 min; heat to 85-95°C at a rate of 5-10°C / 10 min, and hold for 180-200 min.

[0024] Preferably, step S4 specifically includes the following steps:

[0025] S401. The heat insulation layer lay-up-ablation layer preform assembly is packaged using a molding sleeve to obtain the heat insulation layer lay-up-ablation layer preform package assembly;

[0026] S402. Vacuum the heat insulation layer-ablation layer prefabricated packaging assembly;

[0027] S403. Perform a second molding preforming and curing on the heat insulation layer-ablation layer preform packaging assembly to obtain the heat insulation layer-ablation layer preform.

[0028] Preferably, in step S4, the curing conditions during the second molding preforming curing are as follows: pressurize to 3.7-4 MPa at a rate of 1 MPa / 10 min; heat to 90-100°C at a rate of 5-10°C / 10 min, hold for 60-80 min; then heat to 120-130°C at a rate of 5-10°C / 10 min, hold for 120-130 min; then heat to 150-155°C at a rate of 5-10°C / 10 min, hold for 480-500 min.

[0029] Preferably, the density of the ablation layer chopped fiber premix is ​​1400-1600 kg / m³. 3The density of the low-density prepreg fabric in the insulation layer is 800-1200 kg / m³. 3 .

[0030] A second aspect of the present invention provides an integral heat-resistant structure with ablation and heat insulation functional zones, which is prepared by the above-described preparation method.

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

[0032] The present invention discloses a method for preparing an overall heat-resistant structure with ablation and heat insulation functional zones. The heat-resistant structure is designed with functional zones. An ablation layer is prepared on the outside using ablation-resistant short-cut fiber premix. The ablation layer can meet the temperature requirements of withstanding a maximum working temperature of nearly 2000°C and a long-term working temperature of over 1000°C. An insulation layer is prepared on the inside using low-density prepreg fabric. This achieves the temperature requirements of less than 200°C for the load-bearing structure and less than 60°C for the equipment inside the cabin, while also meeting the requirement of lightweight heat-resistant structure.

[0033] The method for preparing the overall heat-resistant structure with ablation and heat insulation functional zones of the present invention involves pre-filling the outer ablation layer with short-cut fiber premixed material in a negative mold for pre-curing and molding, which can realize the special irregular structure design of the outer ablation-resistant layer.

[0034] The method for preparing the overall heat-resistant structure with ablation and heat insulation functional zones of the present invention involves two molding processes and two machining processes for the double-layer functional zone structure. This method not only allows for precise control of the thickness of each functional layer and the achievement of the optimal thickness ratio through simulation calculation to reach the ideal weight state, but also effectively achieves the integral curing of the outer ablation layer and the inner heat insulation layer by controlling the temperature, pressure and time of the two molding processes. This ensures that the inner and outer layers achieve similar curing degrees, guaranteeing the stability and safety of the heat-resistant structure during use. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of the overall heat-resistant structure with irregularly shaped ablation and heat-insulating functional zones prepared in Embodiment 1 of the present invention.

[0036] Figure 2 This is a partial enlarged view of the overall heat-resistant structure with irregularly shaped ablation and heat-insulating functional zones prepared in Embodiment 1 of the present invention.

[0037] Wherein: 1-Irregular area; 2-Ablation layer; 3-Insulation layer. Detailed Implementation

[0038] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0039] Currently, the heat shields of high-speed aircraft mostly adopt a single-layer composite ablation structure. While this structure meets the functional requirements of ablation resistance and heat insulation, it usually cannot meet the weight requirements. Furthermore, since the heat shields of high-speed aircraft need to be assembled with other components, they are usually irregularly shaped structures. In addition, how to ensure the stability of the heat shield structure and the accuracy of its thickness dimensions are also problems that need to be solved.

[0040] Therefore, a first aspect of the present invention provides a method for preparing an integral heat-resistant structure with ablation and heat insulation functional zones, comprising the following steps:

[0041] S1. The ablation layer chopped fiber premix is ​​loaded into the female mold and subjected to the first molding preforming and curing to obtain the ablation layer preform;

[0042] S2. Perform the first machining on the inner surface of the ablation layer preform;

[0043] S3. Lay the low-density prepreg of the heat insulation layer onto the inner surface of the ablation layer preform after the first mechanical processing to obtain the heat insulation layer paving sheet-ablation layer preform assembly;

[0044] S4. Perform a second molding preforming and curing on the heat insulation layer-ablation layer preform assembly to obtain the heat insulation layer-ablation layer preform.

[0045] S5. Perform a second machining operation on the inner surface of the insulation layer of the insulation layer-ablation layer preform;

[0046] S6. Demold the preform of the heat insulation layer-ablation layer to obtain the overall heat-proof structure of the ablation and heat insulation functional zones.

[0047] The method for preparing the overall heat-resistant structure with ablation and thermal insulation functional zones according to embodiments of the present invention firstly involves functional zoning design of the heat-resistant structure. An ablation layer is prepared on the outside using an ablation-resistant short-cut fiber premix, which can withstand a maximum operating temperature of nearly 2000℃ and a long-term operating temperature above 1000℃. An insulation layer is prepared on the inside using low-density prepreg, achieving the requirement that the load-bearing structure's operating temperature is less than 200℃ and the internal equipment's operating temperature is less than 60℃, while also meeting the requirement for a lightweight heat-resistant structure. Secondly, short-cut fiber premix is ​​used for the outer ablation layer... The fiber premix is ​​pre-filled into the female mold and pre-cured, which can realize the special irregular structure design of the outer ablation-resistant layer. Furthermore, the dual-layer functional partition structure is divided into two molding processes and two machining processes. This not only allows for precise control of the thickness of each functional layer and the achievement of the optimal thickness ratio through simulation calculation to achieve the ideal weight state, but also effectively realizes the integrated curing of the outer ablation layer and the inner heat insulation layer by controlling the temperature, pressure and time of the two molding processes. This ensures that the inner and outer layers achieve similar curing degrees, guaranteeing the stability and safety of the heat-resistant structure during use.

[0048] In some implementations, step S1 specifically includes the following steps:

[0049] S101. The ablation layer chopped fiber premix is ​​loaded into a premix preforming container to prepare an ablation layer premix filling block;

[0050] S102. The ablation layer premix filling block is filled into the female mold, and the ablation layer premix filling block is packaged with a molding sleeve to obtain the ablation layer premix filling block-female mold packaging assembly;

[0051] S103. Vacuum the ablation layer premix filling block-vacuum mold packaging assembly;

[0052] S104. The ablation layer premix filling block-vacuum mold packaging assembly is subjected to a first molding preforming and curing to obtain the ablation layer preform.

[0053] The ablation layer chopped fiber premix is ​​filled into the female mold in the form of premix filling blocks. For products with different shape requirements, the size and shape of the filling blocks can be designed to ensure that the premix of irregular female mold can be filled in place and the fiber is evenly distributed so that the shape is not prone to resin accumulation after curing.

[0054] In some embodiments, step S101 specifically includes the following steps: loading the ablation layer chopped fiber premix into a premix preforming container, air-drying it at room temperature for 24-28 hours, and then vacuum-sealing it for 1-2 hours to obtain the ablation layer premix filling block. This reduces the volatile content of the premix, thereby ensuring the release of small molecules inside the product after curing, reducing internal stress, and increasing product strength.

[0055] In some implementations, the airtightness of the female mold is also checked before step S102.

[0056] In some embodiments, a release agent is applied to the surface of the female mold before step S102.

[0057] In some embodiments, in step S102, after the ablation layer premix filling block is filled into the female mold, it is vacuum-formed for 1-2 hours. This reduces the volatile content of the premix, thereby ensuring the release of small molecules inside the product after curing, reducing internal stress, and increasing product strength.

[0058] In some implementations, step S103 specifically includes the following steps:

[0059] The ablation layer premix filling block-vacuum mold packaging assembly is stored at 90°C and below -0.08 MPa for 3-4 hours. This reduces the volatile content of the premix, thereby ensuring the release of small molecules inside the product after curing, reducing internal stress, and increasing product strength.

[0060] In some embodiments, step S104 specifically includes the following steps: after cooling the ablation layer premix filling block-vacuum mold packaging assembly, a first molding preforming and curing is performed to obtain the ablation layer preform.

[0061] In some embodiments, in step S1, the curing conditions during the first molding preforming curing are as follows: pressurize to 3.7-4 MPa at a rate of 1 MPa / 10 min; heat to 85-95°C at a rate of 5-10°C / 10 min, and hold for 180-200 min.

[0062] In some embodiments, in step S1, after the first molding preforming curing, the pre-curing degree of the obtained ablation layer preform is 50%-70%.

[0063] In some embodiments, step S2 further involves depressurizing and cooling the ablation layer preform before performing the first machining.

[0064] Furthermore, the pressure reduction cooling specifically involves cooling the ablation layer preform to below 50°C and reducing the pressure to 0 MPa.

[0065] In some embodiments, before step S3, the low-density prepreg of the insulation layer is placed in an oven at 50°C for 10 minutes for preheating.

[0066] In some embodiments, in step S3, after the low-density prepreg of the insulation layer is laid onto the inner surface of the ablation layer preform after the first machining, it is vacuum-set for 1-2 hours. This eliminates the gaps created by laying the prepreg, allowing the insulation prepreg to adhere sufficiently to the ablation layer.

[0067] In some implementations, step S4 specifically includes the following steps:

[0068] S401. The heat insulation layer lay-up-ablation layer preform assembly is packaged using a molding sleeve to obtain the heat insulation layer lay-up-ablation layer preform package assembly;

[0069] S402. Vacuum the heat insulation layer-ablation layer prefabricated packaging assembly;

[0070] S403. Perform a second molding preforming and curing on the heat insulation layer-ablation layer preform packaging assembly to obtain the heat insulation layer-ablation layer preform.

[0071] In some implementations, step S402 specifically includes the following steps:

[0072] The heat insulation layer-ablation layer preform packaging assembly is stored at 90°C and below -0.08 MPa for 3-4 hours. This reduces the volatile content of the prepreg, thereby ensuring the release of small molecules within the product after curing, reducing internal stress, and increasing product strength.

[0073] In some implementations, step S403 specifically includes the following steps:

[0074] The heat insulation layer-ablation layer preform packaging assembly is cooled to below 60°C and the pressure is reduced to 0 MPa. Then, a second molding pre-forming and curing process is performed to obtain the heat insulation layer-ablation layer preform.

[0075] In some embodiments, step S5 further involves depressurizing and cooling the heat insulation layer-ablation layer preform before performing the second machining.

[0076] In some embodiments, in step S4, the curing conditions during the second molding preforming curing are as follows: pressurize to 3.7-4 MPa at a rate of 1 MPa / 10 min; heat to 90-100°C at a rate of 5-10°C / 10 min, hold for 60-80 min; then heat to 120-130°C at a rate of 5-10°C / 10 min, hold for 120-130 min; then heat to 150-155°C at a rate of 5-10°C / 10 min, hold for 480-500 min.

[0077] In some embodiments, the density of the ablation layer chopped fiber premix is ​​1400-1600 kg / m³. 3 The density of the low-density prepreg fabric in the insulation layer is 800-1200 kg / m³. 3 .

[0078] In some embodiments, the overall heat-resistant structure of the ablation and heat insulation functional zones obtained has a remaining uncarbonized layer of 2-3 mm in thickness.

[0079] A second aspect of the present invention provides an integral heat-resistant structure with ablation and heat insulation functional zones, which is prepared by the above-described preparation method.

[0080] Example 1

[0081] The overall heat-resistant structure with ablation and heat insulation functional zones prepared in this embodiment is as follows: Figure 1 , 2 The external surface shown is an irregularly shaped heat-resistant structure, in which, Figure 1 In the middle, 1 represents the irregular region. Figure 2 In the middle, 2 is the ablation layer and 3 is the heat insulation layer.

[0082] The method for preparing the overall heat-resistant structure with ablation and heat insulation functional zones in this embodiment includes the following steps:

[0083] S1. Preparation of ablation layer preform:

[0084] S101. The ablation layer chopped fiber premix is ​​loaded into a premix preforming container, air-dried at room temperature for 24 hours, and then vacuum-sealed for 2 hours to obtain the ablation layer premix filling block. The ablation layer chopped fiber premix is ​​a 1:1 volume mixture of chopped quartz fiber yarn and acetal resin, with a density of 1600 kg / m³. 3 ;

[0085] S102. Check the airtightness of the female mold, apply a release agent to the surface of the female mold, then fill the ablation layer premix filling block into the female mold, vacuum and shape for 1 hour, and use a special mold plastic sleeve to package the ablation layer premix filling block to obtain the ablation layer premix filling block-female mold packaging assembly.

[0086] S103. The ablation layer premix filling block-vacuum mold packaging assembly is stored at 90℃ and below -0.08MPa for 4 hours.

[0087] S104. After cooling the ablation layer premix filling block-vacuum mold packaging assembly, perform the first molding pre-forming curing. The curing conditions are: pressurize to 4MPa at a rate of 1MPa / 10min; heat to 90℃ at a rate of 8℃ / 10min and hold for 180min to obtain the ablation layer preform. The pre-curing degree of the ablation layer preform is 60%.

[0088] S2. The ablation layer preform is cooled by depressurization to below 50°C and the pressure is reduced to 0MPa. Then the inner surface of the ablation layer preform is machined for the first time.

[0089] S3. Take a low-density prepreg for the insulation layer. The low-density prepreg is a prepreg obtained by impregnating quartz cloth with low-density modified barium phenolic resin. The volume ratio of quartz cloth to low-density modified barium phenolic resin is 2:5, and the density is 800 kg / m³. 3 Cut the insulation layer into the design shape, put the low-density prepreg fabric in the oven at 50°C for 10 minutes for preheating, then lay the low-density prepreg fabric on the inner surface of the ablation layer preform after the first mechanical processing, vacuum set for 2 hours, and obtain the insulation layer paving sheet-ablation layer preform assembly.

[0090] S4. Preparation of the heat insulation layer-ablation layer preform:

[0091] S401. Use a molding sleeve to package the heat insulation layer lay-up sheet-ablation layer preform assembly to obtain the heat insulation layer lay-up sheet-ablation layer preform package assembly;

[0092] S402. The heat insulation layer paving-ablation layer prefabricated packaging assembly is stored at 90℃ and below -0.08MPa for 4 hours;

[0093] S403. Cool the heat insulation layer-ablation layer preform packaging assembly to below 60°C and reduce the pressure to 0MPa. Then, perform a second molding pre-forming curing. The curing conditions for the second molding pre-forming curing are as follows: increase the pressure to 4MPa at a rate of 1MPa / 10min; increase the temperature to 90°C at a rate of 8°C / 10min and hold for 80min; then increase the temperature to 130°C at a rate of 10°C / 10min and hold for 120min; then increase the temperature to 150°C at a rate of 10°C / 10min and hold for 500min to obtain the heat insulation layer-ablation layer preform.

[0094] S5. The heat insulation layer-ablation layer preform is subjected to depressurization and cooling, and then the inner surface of the heat insulation layer of the heat insulation layer-ablation layer preform is subjected to a second machining.

[0095] S6. Demold the prefabricated heat insulation layer-ablation layer to obtain the overall heat-proof structure with ablation and heat insulation functional zones.

[0096] Example 2

[0097] The preparation method of the overall heat-resistant structure with ablation and heat insulation functional zones in this embodiment is the same as that in Example 1 in other steps and process parameters. The difference is that in step S104, the curing conditions are: pressurize to 3.7MPa at a rate of 1MPa / 10min; heat to 95℃ at a rate of 5℃ / 10min; and hold for 180min to obtain the ablation layer preform. The pre-curing degree of the ablation layer preform is 65%.

[0098] Example 3

[0099] The preparation method of the overall heat-resistant structure with ablation and heat insulation functional zones in this embodiment is the same as that in Example 1 in other steps and process parameters. The difference is that in step S104, the curing conditions are: pressurize to 4MPa at a rate of 1MPa / 10min; heat to 85℃ at a rate of 10℃ / 10min; and hold for 200min to obtain the ablation layer preform. The pre-curing degree of the ablation layer preform is 60%.

[0100] Example 4

[0101] The preparation method of the overall heat-resistant structure with ablation and heat insulation functional zones in this embodiment is the same as that in Example 1 in other steps and process parameters. The difference is that in step S104, the curing conditions are: pressurize to 5MPa at a rate of 1MPa / 10min; heat to 110℃ at a rate of 8℃ / 10min; and hold for 180min to obtain the ablation layer preform. The pre-curing degree of the ablation layer preform is 70%.

[0102] Example 5

[0103] The preparation method of the overall heat-resistant structure with ablation and heat insulation functional zones in this embodiment is the same as that in Example 1 in other steps and process parameters. The difference is that in step S104, the curing conditions are: pressurize to 3.2 MPa at a rate of 1 MPa / 10 min; heat to 70°C at a rate of 8°C / 10 min; and hold for 200 min to obtain the ablation layer preform. The pre-curing degree of the ablation layer preform is 50%.

[0104] Example 6

[0105] The preparation method of the overall heat-resistant structure of the ablation and heat insulation functional zones in this embodiment is the same as that in Example 1 in terms of other steps and process parameters. The difference is that in step S403, the curing conditions are as follows: pressurize to 3.7 MPa at a rate of 1 MPa / 10 min; heat to 100°C at a rate of 10°C / 10 min and hold for 60 min; then heat to 120°C at a rate of 8°C / 10 min and hold for 130 min; then heat to 155°C at a rate of 5°C / 10 min and hold for 480 min.

[0106] Example 7

[0107] The preparation method of the overall heat-resistant structure with ablation and heat insulation functional zones in this embodiment is the same as that in Example 1 in terms of other steps and process parameters. The difference is that in step S403, the curing conditions are as follows: pressurize to 4MPa at a rate of 1MPa / 10min; heat to 95℃ at a rate of 5℃ / 10min and hold for 70min; then heat to 125℃ at a rate of 5℃ / 10min and hold for 130min; then heat to 155℃ at a rate of 10℃ / 10min and hold for 490min.

[0108] Example 8

[0109] The preparation method of the overall heat-resistant structure with ablation and heat insulation functional zones in this embodiment is the same as that in Example 1 in other steps and process parameters. The difference is that in step S403, the curing conditions are: pressurize to 4MPa at a rate of 1MPa / 10min; the heating process does not use gradient heating, and the heating program is: heat to 150℃ at a rate of 5℃ / 10min and hold for 600min.

[0110] Example 9

[0111] The preparation method of the overall heat-resistant structure of the ablation and heat insulation functional zones in this embodiment is the same as that in Example 1 in terms of other steps and process parameters. The difference is that in step S403, the curing conditions are as follows: pressurize to 4MPa at a rate of 1MPa / 10min; heat to 110℃ at a rate of 5℃ / 10min and hold for 50min; then heat to 135℃ at a rate of 5℃ / 10min and hold for 120min; then heat to 165℃ at a rate of 10℃ / 10min and hold for 450min.

[0112] Example 10

[0113] The preparation method of the overall heat-resistant structure with ablation and heat insulation functional zones in this embodiment is the same as that in Example 1 in terms of other steps and process parameters. The difference is that in step S403, the curing conditions are as follows: pressurize to 4MPa at a rate of 1MPa / 10min; heat to 80℃ at a rate of 5℃ / 10min and hold for 80min; then heat to 110℃ at a rate of 5℃ / 10min and hold for 130min; then heat to 140℃ at a rate of 10℃ / 10min and hold for 500min.

[0114] Comparative Example 1

[0115] The heat-resistant structure in this comparative example adopts a single-layer ablation layer structure, and the preparation method includes the following steps:

[0116] S101. The ablation layer chopped fiber premix is ​​loaded into a premix preforming container, air-dried at room temperature for 24 hours, and then vacuum-sealed for 2 hours to obtain the ablation layer premix filling block. The ablation layer chopped fiber premix is ​​a 1:1 volume mixture of chopped quartz fiber yarn and acetal resin, with a density of 1600 kg / m³. 3 ;

[0117] S102. Check the airtightness of the female mold, apply a release agent to the surface of the female mold, and then fill the ablation layer premix filling block into the female mold (the thickness of the ablation layer formed in the female mold is the sum of the thickness of the ablation layer and the thickness of the heat insulation layer in Example 1). Vacuum and shape for 1 hour, and use a special mold plastic sleeve to package the ablation layer premix filling block to obtain the ablation layer premix filling block-female mold packaging assembly.

[0118] S103. The ablation layer premix filling block-vacuum mold packaging assembly is stored at 90℃ and below -0.08MPa for 4 hours.

[0119] S104. After cooling the ablation layer premix filling block-vacuum mold packaging assembly, it is subjected to molding pre-forming and curing. The curing conditions are as follows: pressurize to 4MPa at a rate of 1MPa / 10min; heat to 90℃ at a rate of 8℃ / 10min and hold for 80min; then heat to 130℃ at a rate of 10℃ / 10min and hold for 120min; then heat to 150℃ at a rate of 10℃ / 10min and hold for 500min to obtain the ablation layer.

[0120] S105. The obtained ablation layer is machined to obtain a heat-resistant structure.

[0121] The weight of the heat-resistant structure obtained from the above embodiments and comparative examples, as well as the structural stability of the ablation layer and the heat insulation layer in the heat-resistant structure, were measured, and the results are shown in Table 1 below.

[0122] As shown in Table 1, Comparative Example 1, which uses a single-layer ablation layer structure, is heavier than the other examples and does not meet the lightweight requirement. All other conditions are the same across examples, the difference being the curing regime during the two curing processes. Compared to Examples 1-5, the curing regime for the first curing (ablation layer) differs, resulting in different pre-curing degrees of the ablation layer. Table 1 shows that the curing temperature and pressure of the ablation layer in Example 4 were too high, causing minor cracking in the final product's ablation layer. The curing temperature and pressure of the ablation layer in Example 5 were too low, resulting in a lower pre-curing degree. Furthermore, the curing regimes of Examples 4 and 5 were not within the optimal range, leading to a significant difference in curing degree between the ablation layer and the insulation layer, resulting in a large difference in deformation between the two layers and slight delamination between the ablation layer and the insulation layer. This resulted in the product's weather resistance and mechanical strength properties being inferior to Examples 1-3. Compared to Examples 1 and 6-10, the curing regime and pre-curing degree of the insulation layer are different. As can be seen from the data in Table 1, in Example 8, the secondary curing (insulation layer and ablation layer) did not use gradient temperature increase, which led to uncontrollable glue output during the curing process, affecting the product density and easily causing resin accumulation. Ultimately, the mechanical properties of the product were not as good as those of Examples 1, 6, and 7. In Example 9, the curing temperature of the secondary curing was higher than the preferred range, resulting in a small area of ​​cracking in the ablation layer of the final product. In Example 10, the curing temperature of the secondary curing was lower than the preferred range, resulting in a low degree of curing of the product. At the same time, the curing temperatures of the secondary curing in Examples 9 and 10 were not within the preferred range, resulting in a large difference in the degree of curing between the ablation layer and the insulation layer, and a large difference in the deformation of the two layers. Slight delamination of the ablation layer and the insulation layer occurred, resulting in the product's weather resistance and mechanical strength properties being inferior to those of Examples 1, 6, and 7.

[0123] Table 1

[0124]

[0125]

[0126] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A method for preparing an integral heat-resistant structure with ablation and heat insulation functional zones, characterized in that, Includes the following steps: S1. The ablation layer chopped fiber premix is ​​loaded into the female mold and subjected to the first molding preforming and curing to obtain the ablation layer preform; S2. Perform the first machining on the inner surface of the ablation layer preform; S3. Lay the low-density prepreg of the heat insulation layer onto the inner surface of the ablation layer preform after the first mechanical processing to obtain the heat insulation layer paving sheet-ablation layer preform assembly; S4. Perform a second molding preforming and curing on the heat insulation layer-ablation layer preform assembly to obtain the heat insulation layer-ablation layer preform. S5. Perform a second machining operation on the inner surface of the insulation layer of the insulation layer-ablation layer preform; S6. Demold the heat insulation layer-ablation layer preform to obtain the overall heat-proof structure of the ablation and heat insulation functional zones; Step S1 specifically includes the following steps: S101. The ablation layer chopped fiber premix is ​​loaded into a premix preforming container to prepare an ablation layer premix filling block; S102. The ablation layer premix filling block is filled into the female mold, and the ablation layer premix filling block is packaged with a molding sleeve to obtain the ablation layer premix filling block-female mold packaging assembly; S103. Vacuum the ablation layer premix filling block-vacuum mold packaging assembly; S104. Perform a first molding preforming and curing on the ablation layer premix filling block-vacuum mold packaging assembly to obtain the ablation layer preform; In step S1, the curing conditions during the first molding pre-forming curing are as follows: pressurize to 3.7-4MPa at a rate of 1MPa / 10min; heat to 85-95℃ at a rate of 5-10℃ / 10min, and hold for 180-200min. In step S4, the curing conditions during the second molding preforming curing are as follows: pressurize to 3.7-4 MPa at a rate of 1 MPa / 10 min; heat to 90-100℃ at a rate of 5-10℃ / 10 min, hold for 60-80 min; then heat to 120-130℃ at a rate of 5-10℃ / 10 min, hold for 120-130 min; then heat to 150-155℃ at a rate of 5-10℃ / 10 min, hold for 480-500 min.

2. The preparation method according to claim 1, characterized in that: Step S101 specifically includes the following steps: the ablation layer chopped fiber premix is ​​loaded into a premix preforming container, dried at room temperature for 24-28 hours, and then vacuum-preserved for 1-2 hours to obtain the ablation layer premix filling block.

3. The preparation method according to claim 1, characterized in that: In step S102, after the ablation layer premix filling block is filled into the female mold, it is vacuumed and shaped for 1-2 hours.

4. The preparation method according to claim 1, characterized in that: Step S103 specifically includes the following steps: The ablation layer premix filling block-vacuum mold packaging assembly was stored at 90°C and -0.08MPa for 3-4 hours.

5. The preparation method according to claim 1, characterized in that: Step S4 specifically includes the following steps: S401. The heat insulation layer lay-up-ablation layer preform assembly is packaged using a molding sleeve to obtain the heat insulation layer lay-up-ablation layer preform package assembly; S402. Vacuum the heat insulation layer-ablation layer prefabricated packaging assembly; S403. Perform a second molding preforming and curing on the heat insulation layer-ablation layer preform packaging assembly to obtain the heat insulation layer-ablation layer preform.

6. The preparation method according to claim 1, characterized in that: The density of the ablation layer chopped fiber premix is ​​1400-1600 kg / m³. 3 The density of the low-density prepreg fabric in the insulation layer is 800-1200 kg / m³. 3 .

7. An integral heat-resistant structure with ablation and heat insulation functional zones, prepared by the preparation method as described in any one of claims 1-6.

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