Anti-scouring material as well as preparation method and application thereof

Abstract

The invention discloses an anti-scouring material as well as a preparation method and application thereof, and belongs to the technical field of heat insulation layer materials in combustion chambers of solid rocket engines. The anti-scouring material is prepared from aramid fiber fabric, a modified ethylene propylene diene monomer base material and phenolic resin, and the modified ethylene propylene diene monomer base material is prepared from ethylene propylene diene monomer, modified ethylene propylene diene monomer, white carbon black, zinc borate, dicumyl peroxide and triallyl isocyanurate through a rubber mixing process. The anti-scouring material disclosed by the invention has lower density and lower thermal conductivity on the basis of keeping the ablation performance of a traditional material, and can reduce the negative mass of an aircraft. The internal heat insulation layer is prepared by adopting a one-time curing method, so that the production efficiency is greatly improved; meanwhile, interface cleaning and adhesive brushing which are necessary for bonding different materials are omitted, the hidden danger of interface air entrapment and bulging is eliminated, and the occurrence probability of interface debonding is greatly reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of thermal insulation layer materials in a combustion chamber of a solid rocket engine, and in particular relates to an anti-scour material and a preparation method and application thereof. Background Art

[0002] With the increasing demand for aircraft range and delivery capability, as well as the increase in charge and engine combustion time, the requirements for the ablation resistance and erosion resistance of the solid rocket engine combustion chamber insulation layer are getting higher and higher, and the traditional single rubber-based insulation layer can no longer adapt. In recent years, carbon fiber / phenolic-nitrile composite materials have been developed and used as an anti-erosion layer in the areas where the insulation layer is severely eroded, together with other rubber insulation materials, and have achieved good results.

[0003] However, during the ground ignition test of the solid rocket engine, the propellant releases a lot of heat during operation. Due to the high thermal conductivity of carbon fiber, the heat is easily transferred to the bonding interface or even the engine casing, resulting in test failure. At the same time, the relatively high density of carbon fiber will also increase the negative mass of the solid rocket engine and affect the effective range of the aircraft.

[0004] In addition, with the rapid popularization of EPDM insulation materials with excellent comprehensive performance in terms of low density and ablation resistance, more and more EPDM insulation materials, carbon fiber / phenolic-nitrile erosion-resistant materials and sandwich bonding structures of EPDM insulation materials are used in parts of solid rocket engines with severe ablation. However, the polarity of nitrile rubber and EPDM rubber in carbon fiber / phenolic-nitrile erosion-resistant materials is very different, and EPDM is weakly bonded to carbon fiber and nitrile. There are often defects such as air inclusion and bulging during use, which directly leads to the scrapping of the insulation layer in severe cases.

[0005] Furthermore, the current bonding method for carbon fiber / phenolic-nitrile composite materials and rubber insulation materials mainly adopts a secondary curing process, and the layers need to be brushed with glue. The bonding process is complicated, the production cycle is long, and there are many quality risks, which leads to an increase in the product failure rate. Summary of the invention

[0006] In view of the above-mentioned prior art, the present invention selects aramid fiber with lower thermal conductivity and density than carbon fiber to design a scouring material with low density, low thermal conductivity and good compatibility with EPDM insulation material. At the same time, a bonding method of the material is provided to solve the bonding problem of EPDM insulation material and fiber / phenolic-EPDM anti-scouring material sandwich structure, simplify the bonding process, reduce quality risks, and improve the reliability of the structure.

[0007] In order to achieve the above object, the technical solution adopted by the present invention is to provide an anti-scour material, and the raw materials for preparing the material include the following components in parts by weight: 45-55 parts of aramid fiber fabric, 20-35 parts of modified EPDM rubber matrix material and 10-35 parts of phenolic resin; The modified EPDM rubber matrix material is prepared by a rubber refining process using EPDM rubber, modified EPDM rubber, white carbon black, zinc borate, dicumyl peroxide and triallyl isocyanurate as raw materials; the mass ratio of EPDM rubber, modified EPDM rubber, white carbon black, zinc borate, dicumyl peroxide and triallyl isocyanurate is 60:40:10~2:8~10:1~4:2~5; the modified EPDM rubber includes sulfonated EPDM rubber and acrylonitrile grafted EPDM rubber.

[0008] Based on the above technical solution, the present invention can also be improved as follows.

[0009] Further, the raw materials for preparing the anti-scour material include the following components in parts by weight: 54 parts of aramid fiber fabric, 23 parts of modified EPDM rubber matrix material and 23 parts of phenolic resin.

[0010] Furthermore, the aramid fiber fabric is an aramid fiber weft-knitted fabric with a thickness of 1 to 4 mm.

[0011] Furthermore, the phenolic resin is at least one of a thermosetting phenolic resin, a thermoplastic phenolic resin and a modified phenolic resin.

[0012] Furthermore, the phenolic resin is a barium phenolic resin.

[0013] Further, the modified EPDM rubber matrix material is prepared by the following steps: Add modified EPDM rubber, white carbon black, zinc borate, dicumyl peroxide and triallyl isocyanurate to EPDM rubber in sequence. Each time a raw material is added, pass it through the pipe 4 times. After all the raw materials have been added, pass it through the pipe 12 times to obtain the product.

[0014] Furthermore, the mass ratio of the sulfonated EPDM rubber to the acrylonitrile-grafted EPDM rubber is 1:1-3.

[0015] Further, the sulfonated EPDM rubber is prepared by the following steps: Dissolve EPDM rubber in n-heptane, then add concentrated sulfuric acid and acetic anhydride to the resulting solution, react at room temperature for 30 minutes, then add ethanol to terminate the reaction; then add an ethanol solution of metal acetate, stir, flash evaporate to remove the solvent, and dry the residue at 100°C to obtain; Acrylonitrile grafted EPDM rubber is prepared by the following steps: Dissolve EPDM rubber in n-heptane, then add a xylene solution of azobisisobutyronitrile and a xylene solution of acrylonitrile in an inert gas atmosphere; after the reaction is complete, precipitate with acetone, extract the obtained precipitate with N,N'-dimethylformamide by Soxhlet extraction, and then vacuum dry at 60°C to obtain the product.

[0016] The present invention also discloses a method for preparing the anti-scour material, comprising the following steps: S1: dissolving the modified EPDM matrix material in a mixed solvent, then adding phenolic resin to the resulting solution, stirring and dissolving completely to obtain a rubber solution; the mixed solvent is prepared by mixing n-heptane and ethyl acetate in a volume ratio of 2.5~5:2.5~4; the material-liquid ratio of the modified EPDM matrix material and the phenolic resin to the mixed solvent is 0.5g:0.5g:4~6mL; S2: using vacuum dipping to evenly distribute the glue in the aramid fiber fabric to obtain a dipped fabric; S3: The mixed solvent in the impregnated fabric is volatilized by ventilation drying, blasting or heating to obtain the fabric; the ventilation drying time is 6 to 10 hours, the blasting time is 2 to 3 hours, and the heating temperature is 40 to 60°C.

[0017] The present invention also discloses the use of the anti-scour material as a heat insulating layer in a solid rocket engine combustion chamber. The preparation method of the heat insulating layer in the solid rocket engine combustion chamber comprises the following steps: (1) According to the structural size requirements of the engine insulation layer, the EPDM sheet and the anti-scour material are cut into corresponding sizes and shapes, and the cut EPDM sheet includes a bottom EPDM sheet and a surface EPDM sheet; (2) Sandblast, clean and seal the inner surface of the engine casing, then ventilate and air dry for 2 hours; (3) Wrap the bottom EPDM sheet with an airbag and send it into the inner cavity of the shell, and hot press it with the airbag. The hot pressing temperature is 80°C, the hot pressing pressure is 1.0 MPa, and the hot pressing time is 1 hour; (4) Laying the cut anti-scour material on the surface of the bottom EPDM sheet, and hot pressing with an air bag, the hot pressing temperature is 80°C, the hot pressing pressure is 1.0 MPa, and the hot pressing time is 1.5 h; (5) Lay the surface EPDM sheet on the surface of the anti-scour material, and press it with an airbag under cold pressure. The cold pressing pressure is 0.7 MPa and the cold pressing time is 2 h. (6) Airbag pressure curing, curing temperature is 160°C, curing pressure is 1.0MPa, and curing time is 2h; (7) Cool to room temperature.

[0018] The beneficial effects of the present invention are: (1) The anti-scouring material of the present invention has a lower density (less than 1.25 g / cm2) while maintaining the ablation performance of traditional materials. 3 ) and lower thermal conductivity (less than 0.04W / (K·m)), which can reduce the passive mass of the aircraft.

[0019] (2) The anti-scour material of the present invention contains sulfonated EPDM rubber and acrylonitrile-grafted EPDM rubber; among them, sulfonated EPDM rubber can increase the bonding performance between the modified EPDM rubber matrix and the aramid fabric, thereby improving the quality reliability; acrylonitrile-grafted EPDM can improve the bonding strength between the anti-scour material and other thermal insulation materials such as nitrile rubber. The composite application of the two modified EPDM materials can greatly improve the reliability of the thermal insulation structure.

[0020] (3) The anti-scour material of the present invention also contains white carbon black, zinc borate, diisopropylbenzene peroxide and triallyl isocyanurate; among them, white carbon black can enhance the strength and wear resistance of the material, and zinc borate helps to improve the flame retardancy and thermal stability of the material; diisopropylbenzene peroxide (DCP) and triallyl isocyanurate (TAIC) are used as cross-linking agents to further enhance the cross-linking density and heat resistance of the material, so that the modified EPDM rubber matrix material has higher strength and longer service life while maintaining good elasticity.

[0021] (4) The bonding method adopted by the present invention in preparing the thermal insulation layer in the combustion chamber of a solid rocket engine is changed from the traditional secondary curing to primary curing, thereby avoiding the bonding of raw and cooked interfaces, simplifying the production process, and greatly improving the production efficiency; at the same time, it saves the interface cleaning and adhesive application required for bonding different materials, eliminates the hidden dangers of air entrapment and bulging at the interface, and greatly reduces the probability of interface debonding. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 The thermal insulation layer is prepared by the process in Comparative Example 1; Figure 2 The thermal insulation layer is prepared by the process in Example 1. DETAILED DESCRIPTION

[0023] The EPDM rubber used in the embodiment of the present invention is Jilin Chemical 4045.

[0024] The sulfonated EPDM rubber used is prepared by the following steps: Dissolve EPDM in n-heptane to obtain a rubber solution with a concentration of 60 mg / 100 mL; add concentrated sulfuric acid and acetic anhydride twice the molar number of double bonds in the raw rubber to the rubber solution at room temperature, react at room temperature for 30 minutes, terminate the sulfonation reaction with ethanol, treat the sulfonated EPDM with an excess of 40 wt % zinc acetate ethanol solution, stir, flash evaporate the solvent with boiling water, and dry the precipitate at 100° C. to obtain the sulfonated EPDM.

[0025] The acrylonitrile grafted EPDM rubber used is prepared by the following steps: Add measured amounts of EPDM and n-heptane into a four-necked flask protected by nitrogen, stir at 60°C, and after all the EPDM is dissolved (the concentration of EPDM is 60 mg / 100 mL), add xylene (2.5 g / 100 mL) dissolved with azobisisobutyronitrile, and then dropwise add a xylene solution of acrylonitrile (30 g / 100 mL), and the addition is completed within 10 minutes; after the reaction is complete, precipitate the reaction product with acetone while hot, extract all the precipitates with N,N'-dimethylformamide Soxhlet, and vacuum dry at 60°C to obtain the acrylonitrile-grafted EPDM product.

[0026] The remaining raw materials are commercially available.

[0027] The specific implementation modes of the present invention are described in detail below with reference to the embodiments.

[0028] Example 1 An anti-scour material, the raw materials for its preparation include the following components in parts by weight: 52 parts of aramid fiber fabric, 24 parts of modified EPDM rubber matrix material and 24 parts of barium phenolic resin; wherein the aramid fiber fabric is a 2 mm thick aramid fiber double reverse weft knitted fabric; the modified EPDM rubber matrix material is prepared using the following raw materials in parts by mass: 60 parts of EPDM rubber, 20 parts of sulfonated EPDM rubber, 20 parts of acrylonitrile-grafted EPDM rubber, 10 parts of white carbon black, 8 parts of zinc borate, 3 parts of dicumyl peroxide (DCP), and 2 parts of triallyl isocyanurate (TAIC); the preparation method is to add the EPDM rubber into an open mixing mill, and then add the sulfonated EPDM rubber, acrylonitrile-grafted EPDM rubber, white carbon black, zinc borate, dicumyl peroxide and triallyl isocyanurate in sequence, each time adding a raw material, thin pass 4 times, and after all the raw materials are added, thin pass 12 times to obtain the product.

[0029] The anti-scour material in this embodiment is prepared by the following steps: S1: dissolving the modified EPDM matrix material in a mixed solvent, then adding the barium phenolic resin to the resulting solution, stirring and dissolving completely to obtain a glue solution; wherein the mixed solvent is formed by mixing n-heptane and ethyl acetate in a volume ratio of 1:1; the material-liquid ratio of the modified EPDM matrix material and the barium phenolic resin to the mixed solvent is 0.5g:0.5g:5mL; S2: Vacuum dipping is used to evenly distribute the glue solution in the aramid fiber fabric to obtain a dipped fabric; the specific process of vacuum dipping is as follows: Place polytetrafluoroethylene debonding paper, aramid fiber fabric, guide net and demoulding cloth layer by layer on the dipping platform, reserve resin dipping tube and vacuum interface, then package the vacuum bag film, close the dipping tube valve, connect the vacuum pump to vacuumize to pressure ≤-0.09MPa, check the overall vacuum degree, keep the vacuum for 15 minutes, start to put the dipping tube into the glue solution, open the hose valve to start vacuum dipping, continue to vacuum so that the dipping liquid fully penetrates the aramid fiber fabric, stop vacuuming when the resin glue reaches the glue outlet, slowly return to normal pressure, soak for 5 minutes, and ensure that the dipping liquid is completely soaked; S3: Place the dipped fabric in a ventilated and dry place for 8 hours to allow the mixed solvent in the dipped fabric to evaporate.

[0030] The anti-scour material in this embodiment is used to prepare the thermal insulation layer in the combustion chamber of a solid rocket engine, which specifically includes the following steps: (1) According to the structural size requirements of the engine insulation layer, the EPDM sheet and the anti-scour material are cut into corresponding sizes and shapes, and the cut EPDM sheet includes a bottom EPDM sheet and a surface EPDM sheet; (2) Sandblast, clean and seal the inner surface of the engine casing, then ventilate and air dry for 2 hours; (3) Wrap the bottom EPDM sheet with an airbag and send it into the inner cavity of the shell, and hot press it with the airbag. The hot pressing temperature is 80°C, the hot pressing pressure is 1.0 MPa, and the hot pressing time is 1 hour; (4) Laying the cut anti-scour material on the surface of the bottom EPDM sheet, and hot pressing with an air bag, the hot pressing temperature is 80°C, the hot pressing pressure is 1.0 MPa, and the hot pressing time is 1.5 h; (5) Lay the surface EPDM sheet on the surface of the anti-scour material, and press it with an airbag under cold pressure. The cold pressing pressure is 0.7 MPa and the cold pressing time is 2 h. (6) Airbag pressure curing, curing temperature is 160°C, curing pressure is 1.0MPa, and curing time is 2h; (7) After cooling to room temperature in the furnace, take out the engine housing and complete the bonding of the insulation layer inside the engine.

[0031] Example 2 An anti-scour material, the raw materials for its preparation include the following components in parts by weight: 52 parts of aramid fiber fabric, 24 parts of modified EPDM rubber matrix material and 24 parts of barium phenolic resin; wherein the aramid fiber fabric is a 2 mm thick aramid fiber double reverse weft knitted fabric; the modified EPDM rubber matrix material is prepared using the following raw materials in parts by mass: 60 parts of EPDM rubber, 10 parts of sulfonated EPDM rubber, 30 parts of acrylonitrile-grafted EPDM rubber, 10 parts of white carbon black, 8 parts of zinc borate, 3 parts of dicumyl peroxide (DCP), and 2 parts of triallyl isocyanurate (TAIC); the preparation method is to add the EPDM rubber into an open mixing mill, and then add the sulfonated EPDM rubber, acrylonitrile-grafted EPDM rubber, white carbon black, zinc borate, dicumyl peroxide and triallyl isocyanurate in sequence, each time adding a raw material, thinly pass it 4 times, and after all the raw materials are added, thinly pass it 12 times to obtain the product.

[0032] The anti-scour material in this embodiment is prepared by the following steps: S1: dissolving the modified EPDM matrix material in a mixed solvent, then adding the barium phenolic resin to the resulting solution, stirring and dissolving completely to obtain a glue solution; wherein the mixed solvent is formed by mixing n-heptane and ethyl acetate in a volume ratio of 1:1; the material-liquid ratio of the modified EPDM matrix material and the barium phenolic resin to the mixed solvent is 0.5g:0.5g:5mL; S2: Vacuum dipping is used to evenly distribute the glue solution in the aramid fiber fabric to obtain a dipped fabric; the specific process of vacuum dipping is as follows: Place polytetrafluoroethylene debonding paper, aramid fiber fabric, guide net and demoulding cloth layer by layer on the dipping platform, reserve resin dipping tube and vacuum interface, then package the vacuum bag film, close the dipping tube valve, connect the vacuum pump to vacuumize to pressure ≤-0.09MPa, check the overall vacuum degree, keep the vacuum for 15 minutes, start to put the dipping tube into the glue solution, open the hose valve to start vacuum dipping, continue to vacuum so that the dipping liquid fully penetrates the aramid fiber fabric, stop vacuuming when the resin glue reaches the glue outlet, slowly return to normal pressure, soak for 5 minutes, and ensure that the dipping liquid is completely soaked; S3: drying the impregnated fabric at a temperature of 50° C. to volatilize the mixed solvent in the impregnated fabric.

[0033] The anti-scour material in this embodiment is used to prepare the thermal insulation layer in the combustion chamber of a solid rocket engine, which specifically includes the following steps: (1) According to the structural size requirements of the engine insulation layer, the EPDM sheet and the anti-scour material are cut into corresponding sizes and shapes, and the cut EPDM sheet includes a bottom EPDM sheet and a surface EPDM sheet; (2) Sandblast, clean and seal the inner surface of the engine casing, then ventilate and air dry for 2 hours; (3) Wrap the bottom EPDM sheet with an airbag and send it into the inner cavity of the shell, and hot press it with the airbag. The hot pressing temperature is 80°C, the hot pressing pressure is 1.0 MPa, and the hot pressing time is 1 hour; (4) Laying the cut anti-scour material on the surface of the bottom EPDM sheet, and hot pressing with an air bag, the hot pressing temperature is 80°C, the hot pressing pressure is 1.0 MPa, and the hot pressing time is 1.5 h; (5) Lay the surface EPDM sheet on the surface of the anti-scour material, and press it with an airbag under cold pressure. The cold pressing pressure is 0.7 MPa and the cold pressing time is 2 h. (6) Airbag pressure curing, curing temperature is 160°C, curing pressure is 1.0MPa, and curing time is 2h; (7) After cooling to room temperature in the furnace, take out the engine housing and complete the bonding of the insulation layer inside the engine.

[0034] Example 3 An anti-scour material, the raw materials for its preparation include the following components in parts by weight: 54 parts of aramid fiber fabric, 23 parts of modified EPDM rubber matrix material and 23 parts of barium phenolic resin; wherein the aramid fiber fabric is a 2 mm thick aramid fiber double reverse weft knitted fabric; the modified EPDM rubber matrix material is prepared using the following raw materials in parts by mass: 60 parts of EPDM rubber, 20 parts of sulfonated EPDM rubber, 20 parts of acrylonitrile-grafted EPDM rubber, 10 parts of white carbon black, 8 parts of zinc borate, 3 parts of diisopropylbenzene peroxide (DCP), and 2 parts of triallyl isocyanurate (TAIC); the preparation method is to add the EPDM rubber into an open mixing mill, and then add the sulfonated EPDM rubber, acrylonitrile-grafted EPDM rubber, white carbon black, zinc borate, diisopropylbenzene peroxide and triallyl isocyanurate in sequence, each time adding a raw material, thinly pass it 4 times, and after all the raw materials are added, thinly pass it 12 times to obtain the product.

[0035] The anti-scour material in this embodiment is prepared by the following steps: S1: dissolving the modified EPDM matrix material in a mixed solvent, then adding the barium phenolic resin to the resulting solution, stirring and dissolving completely to obtain a glue solution; wherein the mixed solvent is formed by mixing n-heptane and ethyl acetate in a volume ratio of 1:1; the material-liquid ratio of the modified EPDM matrix material and the barium phenolic resin to the mixed solvent is 0.5g:0.5g:5mL; S2: Vacuum dipping is used to evenly distribute the glue solution in the aramid fiber fabric to obtain a dipped fabric; the specific process of vacuum dipping is as follows: Place polytetrafluoroethylene debonding paper, aramid fiber fabric, guide net and demoulding cloth layer by layer on the dipping platform, reserve resin dipping tube and vacuum interface, then package the vacuum bag film, close the dipping tube valve, connect the vacuum pump to vacuumize to pressure ≤-0.09MPa, check the overall vacuum degree, keep the vacuum for 15 minutes, start to put the dipping tube into the glue solution, open the hose valve to start vacuum dipping, continue to vacuum so that the dipping liquid fully penetrates the aramid fiber fabric, stop vacuuming when the resin glue reaches the glue outlet, slowly return to normal pressure, soak for 5 minutes, and ensure that the dipping liquid is completely soaked; S3: Place the dipped fabric in a ventilated and dry place for 8 hours to allow the mixed solvent in the dipped fabric to evaporate.

[0036] The anti-scour material in this embodiment is used to prepare the thermal insulation layer in the combustion chamber of a solid rocket engine, which specifically includes the following steps: (1) According to the structural size requirements of the engine insulation layer, the EPDM sheet and the anti-scour material are cut into corresponding sizes and shapes, and the cut EPDM sheet includes a bottom EPDM sheet and a surface EPDM sheet; (2) Sandblast, clean and seal the inner surface of the engine casing, then ventilate and air dry for 2 hours; (3) Wrap the bottom EPDM sheet with an airbag and send it into the inner cavity of the shell, and hot press it with the airbag. The hot pressing temperature is 80°C, the hot pressing pressure is 1.0 MPa, and the hot pressing time is 1 hour; (4) Laying the cut anti-scour material on the surface of the bottom EPDM sheet, and hot pressing with an air bag, the hot pressing temperature is 80°C, the hot pressing pressure is 1.0 MPa, and the hot pressing time is 1.5 h; (5) Lay the surface EPDM sheet on the surface of the anti-scour material, and press it with an airbag under cold pressure. The cold pressing pressure is 0.7 MPa and the cold pressing time is 2 h. (6) Airbag pressure curing, curing temperature is 160°C, curing pressure is 1.0MPa, and curing time is 2h; (7) After cooling to room temperature in the furnace, take out the engine housing and complete the bonding of the insulation layer inside the engine.

[0037] Comparative Example 1 An anti-scour material, the composition and preparation method are the same as those in Example 1.

[0038] The anti-scour material in this comparative example is used to prepare the thermal insulation layer in the combustion chamber of a solid rocket engine, which specifically includes the following steps: (1) According to the structural size requirements of the engine insulation layer, the EPDM sheet and the anti-scour material are cut into corresponding sizes and shapes, and the cut EPDM sheet includes a bottom EPDM sheet and a surface EPDM sheet; (2) Sandblast, clean and seal the inner surface of the engine casing, then ventilate and air dry for 2 hours; (3) Wrap the bottom EPDM sheet with an airbag and send it into the inner cavity of the shell, and hot press it with the airbag. The hot pressing temperature is 80°C, the hot pressing pressure is 1.0 MPa, and the hot pressing time is 1 hour; (4) Lay the cut anti-scour material on the surface of the bottom EPDM sheet and perform hot pressing with an air bag at a temperature of 80°C, a pressure of 1.0 MPa and a time of 1.5 h. Then perform the first curing at a temperature of 160°C, a time of 2 h and a pressure of 1.0 MPa. After cooling to room temperature, remove the engine from the heating device.

[0039] (5) Clean the solidified flushing material with chemically pure ethyl acetate, let it stand for 1 hour, then apply CH238, and let it stand for another hour; (6) Laying the surface EPDM sheet on the surface of the anti-scour material, and laminating it by airbag pressurization and hot pressing, with a hot pressing pressure of 0.7 MPa and a hot pressing time of 2 h; (7) After hot pressing, check that there is no abnormality on the surface and then use air bag to pressurize for secondary curing. The curing temperature is 160°C, the curing pressure is 1.0 MPa, and the curing time is 2 hours; (8) After cooling to room temperature in the furnace, take out the engine casing and complete the bonding of the insulation layer inside the engine.

[0040] The difference between Comparative Example 1 and Example 1 is that, for the same anti-scour material, Example 1 adopts the one-time curing bonding of the present invention, while Comparative Example 1 adopts the traditional two-time curing bonding.

[0041] Comparative Example 2 An anti-scour material, the raw materials for its preparation include the following components in parts by weight: 52 parts of carbon fiber fabric, 24 parts of nitrile rubber and 24 parts of barium phenolic resin; wherein the carbon fiber fabric is a 2mm thick carbon fiber weft knitted fabric preform.

[0042] The anti-scour material in this comparative example is prepared by the following steps: S1: First, completely dissolve the nitrile rubber with ethyl acetate, then add the barium phenolic resin, and stir evenly to prepare a glue solution; S2: vacuum dipping is used to evenly distribute the glue in the carbon fiber weft knitted fabric preform, and the vacuum dipping process is the same as that in Example 1; S3: Place the impregnated fabric in a ventilated and dry place for 8 hours to allow the solvent in the impregnated fabric to evaporate.

[0043] The anti-scour material in this comparative example is used to prepare the thermal insulation layer in the combustion chamber of a solid rocket engine, and the specific preparation process is the same as that in Example 1.

[0044] Experimental example The materials and products obtained in the examples and comparative examples were tested by the methods described in "Determination of Density of Composite Solid Propellants, Liners and Insulation Materials" (QJ917A-97), "Hot Wire Method for Determination of Thermal Conductivity of Rubber" (GB / T 11205-2009), "Ablation Test Method for Ablative Materials" (GJB323A-96) and the method of visually observing the apparent quality of the insulation layer. The results are shown in Table 1.

[0045] Table 1 Comparison of material performance data

[0046] From the results in Table 1, it can be seen that the anti-scour materials obtained in Examples 1 to 3 have lower density and lower thermal conductivity than the anti-scour materials obtained in Comparative Example 2, but the oxyacetylene wire ablation rate is basically the same. In addition, compared with Comparative Example 1, the present invention can be directly bonded to the thermal insulation layer without interface treatment, cleaning, gluing, and secondary bonding, which not only reduces the process and production cycle and improves production efficiency, but more importantly, it eliminates the use of solvents, adhesives and other materials, reduces costs, and reduces the possibility of defects such as bulging and debonding, greatly improving the qualified rate of the product. In addition, the thermal insulation layer prepared by the traditional secondary curing bonding preparation process in Comparative Example 1 is prone to bulging ( Figure 1 ), while the thermal insulation layer prepared by the one-time curing bonding process in this application will not have bulging ( Figure 2 ) Although the specific implementation of the present invention is described in detail in conjunction with the embodiments, it should not be understood as limiting the scope of protection of this patent. Within the scope described in the claims, various modifications and variations that can be made by those skilled in the art without creative work still fall within the scope of protection of this patent.

Claims

1. An anti-scour material, characterized in that: The raw materials for preparation include the following components in parts by weight: 45-55 parts of aramid fiber fabric, 20-35 parts of modified EPDM rubber matrix material and 10-35 parts of phenolic resin; The modified EPDM rubber matrix material is prepared by a rubber refining process using EPDM rubber, modified EPDM rubber, white carbon black, zinc borate, dicumyl peroxide and triallyl isocyanurate as raw materials; the mass ratio of the EPDM rubber, modified EPDM rubber, white carbon black, zinc borate, dicumyl peroxide and triallyl isocyanurate is 60:40:10-2:8-10:1-4:2-5; the modified EPDM rubber includes sulfonated EPDM rubber and acrylonitrile-grafted EPDM rubber.

2. The anti-scour material according to claim 1, characterized in that: The raw materials for preparation include the following components in parts by weight: 54 parts of aramid fiber fabric, 23 parts of modified EPDM rubber matrix material and 23 parts of phenolic resin.

3. The anti-scour material according to claim 1 or 2, characterized in that: The aramid fiber fabric is an aramid fiber weft-knitted fabric with a thickness of 1-4 mm.

4. The anti-scour material according to claim 1 or 2, characterized in that: The phenolic resin is at least one of a thermosetting phenolic resin, a thermoplastic phenolic resin and a modified phenolic resin.

5. The anti-scour material according to claim 4, characterized in that: The phenolic resin is barium phenolic resin.

6. The anti-scour material according to claim 1, characterized in that: The modified EPDM rubber matrix material is prepared by the following steps: Add modified EPDM rubber, white carbon black, zinc borate, dicumyl peroxide and triallyl isocyanurate to EPDM rubber in sequence. Each time a raw material is added, pass it through the pipe 4 times. After all the raw materials have been added, pass it through the pipe 12 times to obtain the product.

7. The anti-scour material according to claim 1, characterized in that: The mass ratio of the sulfonated EPDM rubber to the acrylonitrile-grafted EPDM rubber is 1:1-3.

8. The anti-scour material according to claim 7, characterized in that: The sulfonated EPDM rubber is prepared by the following steps: Dissolve EPDM rubber in n-heptane, then add concentrated sulfuric acid and acetic anhydride to the resulting solution, react at room temperature for 30 minutes, then add ethanol to terminate the reaction; then add an ethanol solution of metal acetate, stir, flash evaporate to remove the solvent, and dry the residue at 100°C to obtain; The acrylonitrile-grafted EPDM rubber is prepared by the following steps: Dissolve EPDM rubber in n-heptane, then add a xylene solution of azobisisobutyronitrile and a xylene solution of acrylonitrile in an inert gas atmosphere; after the reaction is complete, precipitate with acetone, extract the obtained precipitate with N,N'-dimethylformamide by Soxhlet extraction, and then vacuum dry at 60°C to obtain the product.

9. The method for preparing the anti-scour material according to any one of claims 1 to 8, characterized in that: The following steps are involved: S1: dissolving the modified EPDM matrix material in a mixed solvent, then adding phenolic resin to the resulting solution, stirring and dissolving completely to obtain a glue solution; the mixed solvent is prepared by mixing n-heptane and ethyl acetate in a volume ratio of 2.5-5:2.5-4; the material-liquid ratio of the modified EPDM matrix material and the phenolic resin to the mixed solvent is 0.5g:0.5g:4-6mL; S2: using vacuum dipping to evenly distribute the glue in the aramid fiber fabric to obtain a dipped fabric; S3: volatilize the mixed solvent in the dipped fabric by ventilation drying, blowing or heating treatment to obtain the fabric; the ventilation drying time is 6 to 10 hours, the blowing time is 2 to 3 hours, and the heating temperature is 40 to 60°C.

10. Use of the erosion-resistant material according to any one of claims 1 to 8 as a heat insulating layer in a combustion chamber of a solid rocket engine, characterized in that: The method for preparing the thermal insulation layer in the combustion chamber of a solid rocket engine comprises the following steps: (1) According to the structural size requirements of the engine insulation layer, the EPDM sheet and the anti-scour material are cut into corresponding sizes and shapes, and the cut EPDM sheet includes a bottom EPDM sheet and a surface EPDM sheet; (2) Sandblast, clean and seal the inner surface of the engine casing, then ventilate and air dry for 2 hours; (3) Wrap the bottom EPDM sheet with an airbag and send it into the inner cavity of the shell, and hot press it with the airbag. The hot pressing temperature is 80°C, the hot pressing pressure is 1.0 MPa, and the hot pressing time is 1 hour; (4) Laying the cut anti-scour material on the surface of the bottom EPDM sheet, and hot pressing with an air bag, the hot pressing temperature is 80°C, the hot pressing pressure is 1.0 MPa, and the hot pressing time is 1.5 h; (5) Lay the surface EPDM sheet on the surface of the anti-scour material, and press it with airbags under cold pressure. The cold pressing pressure is 0.7 MPa and the cold pressing time is 2 h. (6) Airbag pressure curing, curing temperature is 160°C, curing pressure is 1.0MPa, and curing time is 2h; (7) Cool to room temperature.

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