Composite corrosion protection layer for pressure hull section and method of forming

Abstract

The present application relates to a kind of composite pressure cabin section corrosion protection layer and forming method;Including the following steps: composite pressure cabin section surface is coated with epoxy resin, forms waterproof layer;Polyurea resin and volatile solvent type polymerization inhibitor are mixed, obtain impregnation liquid, continuous fiber or fabric is impregnated in impregnation liquid, after impregnation, traction, winding on waterproof layer, form polyurea continuous fiber reinforced layer, heat radiation mode is used to irradiate during winding;Polyurea is sprayed on the surface of polyurea continuous fiber reinforced layer, and heated and solidified, forms polyurea layer on polyurea continuous fiber reinforced layer, by the design of the forming method of composite pressure cabin section corrosion protection layer to solve the existing polyurea protection layer in the laying / recovery and when underwater cruising may occur knock, cause polyurea protection layer peeling, damage etc., cause the connectivity failure of polyurea protection layer and composite pressure cabin section technical problem.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of composite material anticorrosion layer, in particular to a composite material pressure cabin section corrosion-resistant protective layer and forming method. BACKGROUND

[0002] At present, AUV / UUV has been widely used in ocean exploration, and composite material pressure cabin body has better weight reduction effect than metal shell and is widely used in this technical field. At present, the protective layer usually uses paint or soft polyurea as the protective layer to protect the shell, and the main purpose is to reduce the performance decline caused by water absorption of the composite material and other negative effects in seawater, such as marine organism adhesion. The paint layer generally has poor effect on preventing water absorption of the composite material, because the main component of the paint is epoxy or other types of resin, which is cured to form a relatively dense resin layer. Under long-term seawater immersion, water will spread inward through the paint layer. Polyurea protection is a kind of protective layer material more used in the field of ocean at present, and the composite material pressure shell with polyurea protective layer has been subjected to long-term sea trial and is a kind of good protective material.

[0003] However, the polyurea protective layer also has disadvantages, such as the polyurea protective layer may be knocked during deployment / recovery and underwater cruising, which may cause peeling and damage of the polyurea protective layer, resulting in delamination and debonding of the polyurea protective layer and the composite material pressure cabin section, and the protection fails. Therefore, how to effectively improve the connection performance of the polyurea protective layer and the composite material pressure cabin section is one of the main problems of research institutions at present. At present, through polyurea modification, the adhesion performance of the composite material and the polyurea protective layer can be improved to a certain extent, but it still cannot achieve the expected target.

[0004] CN205392916U discloses a kind of fiber reinforced resin-based composite material cylinder impact protection structure, including fiber reinforced resin-based composite material cylinder, bottom coating layer that is sprayed on the surface of the fiber reinforced resin-based composite material cylinder and impact protection layer that is arranged on the bottom coating layer, the impact protection layer is polyurea protective layer. By spraying polyurea coating on the outer surface of the fiber reinforced resin-based composite material cylinder, the deformation and damage problem of the cylinder when impacted can be effectively solved, and the polyurea coating has the advantages of weather resistance, ultraviolet resistance, strong adhesion, good corrosion resistance and high mechanical strength, and has a wide application in the impact protection of resin-based composite material cylinder. However, the sprayed polyurea coating is also prone to damage after being knocked, which cannot meet the long-term use underwater and may cause performance decline due to water absorption of the local material of the pressure shell.

[0005] Therefore, in view of the above problems, the present application urgently needs to provide a composite material pressure cabin section corrosion-resistant protective layer and forming method. SUMMARY

[0006] The present application aims to provide a composite pressure cabin section corrosion-resistant protective layer and a forming method, which solves the technical problem that the existing polyurea protective layer may be bumped during deployment / recovery and underwater cruising, causing the polyurea protective layer to peel and be damaged, resulting in delamination and debonding of the polyurea protective layer and the composite pressure cabin section, and protection failure.

[0007] The present application provides a composite pressure cabin section corrosion-resistant protective layer forming method, which comprises the following steps:

[0008] S1) coating epoxy resin on the surface of the composite pressure cabin section to form a waterproof layer;

[0009] S2) mixing polyurea resin and a volatile solvent type polymerization inhibitor to obtain an impregnating solution, impregnating continuous fibers or fabric in the impregnating solution, and after impregnation, pulling and winding on the waterproof layer to form a polyurea continuous fiber reinforced layer, and using heat radiation during the winding process;

[0010] S3) spraying polyurea on the surface of the polyurea continuous fiber reinforced layer and heating and curing to form a polyurea layer on the polyurea continuous fiber reinforced layer.

[0011] Preferably, in step S2, the continuous fibers or fabric after impregnation are first irradiated on the waterproof layer before winding the waterproof layer, so that the surface temperature of the waterproof layer reaches 40-50℃, and the continuous fibers or fabric are wound and heat irradiation is continuously performed.

[0012] Preferably, the pulling speed in step S2 is 0.5-1.0 m / s.

[0013] Preferably, the volatile solvent type polymerization inhibitor comprises one of ethyl acetate, acetone and anhydrous ethanol.

[0014] Preferably, the winding angle of the continuous fibers or fabric is ±45°.

[0015] Preferably, the thickness of the polyurea continuous fiber reinforced layer is 0.5-2 mm.

[0016] Preferably, the thickness of the waterproof layer is 1-2 mm, and the thickness of the polyurea layer is 0.5-2 mm.

[0017] Preferably, in step S2, after the impregnated continuous fibers or fabric are wound, the polyurea continuous fiber reinforced layer is observed, and after the surface of the polyurea continuous fiber reinforced layer is free of stickiness and impregnating solution shedding, the product is transferred to a curing oven for curing.

[0018] Preferably, the curing temperature in step S3 is 40-50℃.

[0019] The application further provides a composite pressure cabin section corrosion-resistant protective layer obtained by the composite pressure cabin section corrosion-resistant protective layer forming method.

[0020] The composite pressure cabin section corrosion-resistant protective layer and the forming method provided by the application have the following advantages compared with the prior art.

[0021] 1. By the composite pressure cabin section corrosion-resistant protective layer forming method, the polyurea and continuous fibers or other reinforcing fabrics are impregnated and wound on the outer surface of the composite pressure cabin section to form a polyurea continuous fiber reinforced layer. The polyurea continuous fiber reinforced layer formed in this way has good continuity. Even when impacted, the composite pressure cabin section is not directly exposed to the outside due to the presence of continuous reinforcement, achieving the purpose of effective protection.

[0022] 2. By the wet winding method, polyurea and solvent type polymerization inhibitor are added to the glue tank to ensure that the polyurea system in the glue tank cannot self-cure. The continuous fibers or fabrics are introduced into the glue tank through the tension roller to complete the impregnation of the continuous fibers or fabrics with polyurea. The continuous fibers or fabrics are wound on the composite pressure cabin according to the preset linear type. The polyurea continuous fiber reinforced layer has a certain thickness, usually 0.5-2mm. After winding, if the polymerization inhibitor cannot be completely volatilized, voids will be generated during the subsequent polyurea curing. The presence of these voids will cause the hardness of the polyurea to decrease, and the voids will become a weak point for water to enter the composite material through the polyurea layer. Therefore, in order to allow the polyurea to cure completely without voids, the polymerization inhibitor must be completely volatilized, and the polyurea layer has a controllable window time. In the forming process, volatile solvent type polymerization inhibitor is used. This type of polymerization inhibitor can be quickly removed from the polyurea after being heated, achieving the purpose of controllable reaction window. BRIEF DESCRIPTION OF DRAWINGS

[0023] In order to more clearly illustrate the specific embodiments of the application or the technical solutions in the prior art, the following will briefly introduce the drawings needed to be used in the specific embodiments or prior art description. Obviously, the drawings in the following description are some embodiments of the application, and those skilled in the art can also obtain other drawings according to these drawings without creative labor.

[0024] Figure 1 The composite pressure cabin section corrosion-resistant protective layer forming method described in the background art;

[0025] Figure 2 The composite pressure cabin section corrosion-resistant protective layer described in the application;

[0026] Reference numerals:

[0027] 1. composite pressure cabin section; 2. waterproof layer; 3. polyurea continuous fiber reinforced layer; 4. polyurea layer. DETAILED DESCRIPTION

[0028] The technical solutions of the present application will be described clearly and completely below in conjunction with the drawings. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0029] As shown in the drawings, the present application provides a composite pressure cabin section corrosion-resistant protective layer forming method, comprising the following steps: Figure 1

[0030] S1) coating epoxy resin on the surface of the composite pressure cabin section 1 to form a waterproof layer 2;

[0031] S2) mixing polyurea resin and volatile solvent type polymerization inhibitor to obtain an impregnating solution, impregnating continuous fibers or fabrics in the impregnating solution, after impregnation, pulling and winding on the waterproof layer 2 to form a polyurea continuous fiber reinforced layer 3, and using heat radiation to irradiate during winding;

[0032] S3) spraying polyurea on the surface of the polyurea continuous fiber reinforced layer 3, heating and curing to form a polyurea layer 4 on the polyurea continuous fiber reinforced layer.

[0033] The present application proposes a composite pressure cabin section corrosion-resistant protective layer forming method, impregnates polyurea and continuous fibers or other reinforcing fabrics, and winds them on the outer surface of the composite pressure cabin section 1 to form a polyurea continuous fiber reinforced layer. The polyurea continuous fiber reinforced layer formed in this way has good continuity. Even when impacted, the composite pressure cabin section is not directly exposed to the outside due to the presence of continuous reinforcement, achieving the purpose of effective protection.

[0034] ​The present application adds polyurea into the glue groove in the wet winding mode, adds the solvent type polymerization inhibitor, ensures that the polyurea system in the glue groove cannot self-cure, introduces the continuous fiber or fabric into the glue groove through the tension roller, completes the impregnation of the continuous fiber or fabric and the polyurea, and winds the continuous fiber or fabric on the composite pressure cabin according to the preset linear type; the polyurea continuous fiber reinforced layer has a certain thickness, usually 0.5-2mm, after winding, if the polymerization inhibitor cannot be completely volatilized, voids will be generated during the subsequent polyurea curing, the existence of the voids will cause the hardness of the polyurea to be reduced, and the voids will become the weak point of water entering the composite material through the polyurea layer. Therefore, in order to make the polyurea curing complete without voids, the polymerization inhibitor must be completely volatilized, the projection window time of the polyurea layer is controllable, and in the forming process, the volatile solvent type polymerization inhibitor is used, which can be quickly removed from the polyurea after being heated, so that the reaction window is controllable.

[0035] The present application designs a specific winding angle through linear type, and recommends using ±45°, so that the impact load can be more effectively protected.

[0036] In step S2 of the present application, the impregnated continuous fiber or fabric is first irradiated before winding the waterproof layer 2, so that the surface temperature of the waterproof layer 2 reaches 40-50℃, and the continuous fiber or fabric is wound and continuously irradiated.

[0037] Polyurea is sprayed outside the polyurea continuous fiber reinforced layer, heated and cured, and a polyurea layer 4 is formed on the polyurea continuous fiber reinforced layer, which can play a waterproof effect.

[0038] The continuous fiber of the present application is carbon fiber or glass fiber, preferably glass fiber.

[0039] The thickness of the polyurea layer 4 of the present application is ≤2mm.

[0040] The pulling speed in step S2 of the present application is 0.5-1.0m / s, which can ensure that the polymerization inhibitor is fully volatilized without affecting the production efficiency.

[0041] In some embodiments, the volatile solvent type polymerization inhibitor is selected from one of ethyl acetate, acetone and anhydrous ethanol, preferably ethyl acetate.

[0042] In some embodiments, the thickness of the polyurea continuous fiber reinforced layer 3 is 0.5-2mm, preferably the thickness of the polyurea continuous fiber reinforced layer 3 is 1.0mm, which can protect the composite pressure cabin section without increasing the overall weight too much.

[0043] In some embodiments, the thickness of the waterproof layer 2 is 1-2 mm, preferably, the thickness of the waterproof layer 2 is 1.5 mm; the thickness of the polyurea layer 4 is 0.5-2 mm, preferably, the thickness of the polyurea layer is 1.0 mm.

[0044] Specifically, in step S2, after the impregnated continuous fibers or fabrics are wound, the polyurea continuous fiber reinforced layer is observed, the surface of the polyurea continuous fiber reinforced layer 3 is not sticky and no impregnating liquid is dropped, then the product is transferred to a curing oven for curing.

[0045] Specifically, the curing temperature in step S3 is 40-50℃.

[0046] The application also provides a composite pressure cabin section corrosion-resistant protective layer obtained by the forming method of the composite pressure cabin section corrosion-resistant protective layer.

[0047] The application adds the polyurea continuous fiber reinforced layer 3 between the waterproof layer 2 and the polyurea layer 4, and the existence of the continuous reinforcement can prevent the composite pressure cabin section from being directly exposed to the outside when it is impacted, thereby achieving the purpose of effective protection.

[0048] Example 1

[0049] The forming method of the composite pressure cabin section corrosion-resistant protective layer comprises the following steps:

[0050] 101) coating epoxy resin on the surface of the composite pressure cabin section 1 to form a waterproof layer 2;

[0051] 102) mixing polyurea resin and a volatile solvent type polymerization inhibitor to obtain an impregnating liquid, impregnating continuous fibers or fabrics in the impregnating liquid, and then pulling and winding the continuous fibers or fabrics on the waterproof layer 2 to form a polyurea continuous fiber reinforced layer 3, and the winding process is performed by using heat radiation;

[0052] 103) spraying polyurea on the surface of the polyurea continuous fiber reinforced layer 3 and heating and curing to form a polyurea layer 4 on the polyurea continuous fiber reinforced layer.

[0053] In step 102, before the impregnated continuous fibers or fabrics are wound on the waterproof layer 2, the waterproof layer 2 is irradiated to make the surface temperature of the waterproof layer 2 reach 40℃, and the continuous fibers or fabrics are wound and continuously irradiated.

[0054] The continuous fibers in this embodiment are glass fibers.

[0055] The thickness of the polyurea layer 4 of the application is 2 mm.

[0056] The pulling speed in step 102 in the embodiment is 0.5 m / s.

[0057] The volatile solvent type polymerization inhibitor in the embodiment is ethyl acetate.

[0058] The thickness of the polyurea continuous fiber reinforced layer 3 in the embodiment is 2 mm.

[0059] The thickness of the waterproof layer 2 in the embodiment is 1 mm.

[0060] In step S2 in the embodiment, after the impregnated continuous fiber or fabric is wound, the polyurea continuous fiber reinforced layer is observed, and after the surface of the polyurea continuous fiber reinforced layer 3 is not sticky and no impregnation liquid falls off, the product is transferred into a curing oven for curing.

[0061] The curing temperature in step S3 in the embodiment is 40℃.

[0062] The test piece is prepared by the above method, a pendulum impact test is carried out according to the ASTM D256 standard, the pendulum energy is 120 J, the impact speed is 3.8 m / s, after 1 impact, the test piece is soaked in water for 5 days, the water absorption rate is calculated, the compression strength retention rate, the bending strength retention rate and the interlaminar shear force retention rate of the test piece after soaking for 5 days are calculated, and the surface of the test piece is observed. See Table 1.

[0063] Example Two

[0064] The difference between the embodiment and example one is step 102, in the embodiment, the impregnated continuous fiber or fabric is first irradiated before being wound on the waterproof layer 2, so that the surface temperature of the waterproof layer 2 reaches 50℃, and the continuous fiber or fabric is continuously irradiated.

[0065] The continuous fiber in the embodiment is glass fiber.

[0066] The thickness of the polyurea layer 4 of the application is 2 mm.

[0067] The pulling speed in step 102 in the embodiment is 1.0 m / s.

[0068] The volatile solvent type polymerization inhibitor in the embodiment is acetone.

[0069] The thickness of the polyurea continuous fiber reinforced layer 3 in the embodiment is 0.5 mm.

[0070] The thickness of the waterproof layer 2 in the embodiment is 2 mm.

[0071] In step S2 in the embodiment, after the impregnated continuous fiber or fabric is wound, the polyurea continuous fiber reinforced layer is observed, and after the surface of the polyurea continuous fiber reinforced layer 3 is not sticky and no impregnation liquid falls off, the product is transferred into a curing oven for curing.

[0072] The curing temperature in step S3 in this embodiment is 50℃.

[0073] The test piece is prepared according to the above method, and the test method is the same as that in Example 1, and is shown in Table 1.

[0074] Example Three

[0075] The difference between this embodiment and Example 1 is step 102. In this embodiment, the impregnated continuous fiber or fabric is first irradiated to make the surface temperature of the waterproof layer 2 reach 45℃ before being wound on the waterproof layer 2, and the continuous fiber or fabric is continuously irradiated.

[0076] The continuous fiber in this embodiment is glass fiber.

[0077] The thickness of the polyurea layer 4 of the present application is 2mm.

[0078] The pulling speed in step 102 in this embodiment is 0.75m / s.

[0079] The volatile solvent type polymerization inhibitor in this embodiment is selected to be anhydrous ethanol.

[0080] The thickness of the polyurea continuous fiber reinforced layer 3 in this embodiment is 1.0mm.

[0081] The thickness of the waterproof layer 2 in this embodiment is 1.5mm.

[0082] In step S2 in this embodiment, after the impregnated continuous fiber or fabric is wound, the polyurea continuous fiber reinforced layer is observed, and after the surface of the polyurea continuous fiber reinforced layer 3 is not sticky and no impregnating liquid is dropped, the product is transferred to a curing oven for curing.

[0083] The curing temperature in step S3 in this embodiment is 45℃.

[0084] The test piece is prepared according to the above method, and the test method is the same as that in Example 1, and is shown in Table 1.

[0085] Comparative Example 1

[0086] The difference between this embodiment and Example 1 is step 102. In this embodiment, the continuous fiber or fabric is impregnated in the polyurea resin, and after impregnation, it is pulled and wound on the waterproof layer 2 to form the polyurea continuous fiber reinforced layer 3 (without the step of irradiating the waterproof layer 2, and there is also no heat irradiation process during the winding of the polyurea continuous fiber).

[0087] The test piece is prepared according to the above method, and the test method is the same as that in Example 1, and is shown in Table 1.

[0088] Comparative Example 2

[0089] The difference between the example one and the comparative example one is the step 102, the comparative example one is to dip the continuous fiber or fabric into the polyurea resin, after the dipping, the continuous fiber or fabric is pulled and wound on the waterproof layer 2 to form the polyurea continuous fiber reinforced layer 3, and there is a heat irradiation process in the process of winding the polyurea continuous fiber, but there is no heating step for the waterproof layer 2.

[0090] The test pieces are prepared according to the above method, and the test method is the same as that of example one, and the test results are shown in table 1.

[0091] Comparative example 3

[0092] The difference between the example one and the comparative example 3 is that the pulling speed is 1.1 m / s.

[0093] The test pieces are prepared according to the above method, and the test method is the same as that of example one, and the test results are shown in table 1.

[0094] Comparative example 4

[0095] The difference between the example one and the comparative example 4 is that the pulling speed is 0.4 m / s.

[0096] The test pieces are prepared according to the above method, and the test method is the same as that of example one, and the test results are shown in table 1.

[0097] Comparative example 5

[0098] The difference between the example one and the comparative example 5 is that there is no polyurea continuous fiber reinforced layer 3, and the thickness of the polyurea layer is 4 mm.

[0099] The test pieces are prepared according to the above method, and the test method is the same as that of example one, and the test results are shown in table 1.

[0100] Table 1 Physical properties of test pieces

[0101]

[0102] The polyurea continuous fiber reinforced layer 3 is added between the waterproof layer 2 and the polyurea layer 4 through the corrosion-resistant protective layer of the composite pressure cabin section, and the existence of the continuous reinforcement can prevent the composite pressure cabin section from being directly exposed to the outside when impacted, thereby achieving the purpose of effective protection.

[0103] Compared with the example one, the water absorption of the comparative example one increases, and the compression strength retention rate, the bending strength retention rate and the interlaminar shear retention rate after soaking for 5 days decrease, which shows that the heating of the waterproof layer and the heat irradiation in the winding process have an important influence on the overall performance, the temperature does not meet the requirement, the polymerization inhibitor cannot be fully volatilized, and the overall mechanical properties of the test piece are affected, and the water absorption is high.

[0104] The waterproof layer 2 is irradiated by heat before the polyurea continuous fiber winding, and is irradiated by heat during the polyurea continuous fiber winding, so that the blocking agent is completely volatilized, no blocking agent is left when the polyurea is cured, no gap is generated, the overall strength and compactness of the polyurea continuous fiber reinforced layer 3 are ensured, and water entering the composite material through the polyurea layer can be avoided.

[0105] Compared with example one, the water absorption of comparative example 2 increases, and the compression strength retention rate, the bending strength retention rate and the interlaminar shear retention rate after soaking for 5 days decrease to some extent, so it can be seen that heating the waterproof layer during preparation has a certain influence on the overall performance of the material. If the temperature of the waterproof layer cannot reach the required temperature, the blocking agent wrapped around the waterproof layer cannot be fully volatilized, which will affect the overall mechanical properties, and at the same time, gaps will be generated in the polyurea continuous fiber reinforced layer, resulting in a high increase in water absorption.

[0106] Compared with example one, the pulling speed of comparative example 3 is set to 1.1 m / s, which is higher than that of example one, but the water absorption is greater than that of example one, and the compression strength retention rate, the bending strength retention rate and the interlaminar shear retention rate after soaking for 5 days are lower than those of example one, so it can be seen that the setting of the pulling speed plays a crucial role in the compactness of the polyurea continuous fiber reinforced layer 3.

[0107] Compared with example one, the pulling speed of comparative example 4 is set to 0.4 m / s, which is lower than that of example one, and the water absorption is greater than that of example one, and the compression strength retention rate, the bending strength retention rate and the interlaminar shear retention rate after soaking for 5 days are lower than those of example one. When the pulling speed is less than 0.5 m / s, the polyurea that has been constructed is cured, and the polyurea that has not been constructed is in a semi-solid state due to the volatilization of the solvent during the process, which is attached to the surface of the composite material, which also causes a decrease in performance.

[0108] Compared with example one, comparative example 5 has no polyurea continuous fiber reinforced layer 3, and only the thickness of the polyurea layer is increased to 4 mm. Although it can ensure a good water absorption, there is no polyurea continuous fiber reinforced layer 3, and the compression strength retention rate, the bending strength retention rate and the interlaminar shear retention rate after soaking for 5 days decrease by 27%, 20% and 25% respectively (only 5-6% in example one), which indicates that simply increasing the thickness of the polyurea layer has limited effect on improving long-term mechanical properties, and after impact, the carbon fiber layer is exposed, which cannot meet the requirements of impact resistance.

[0109] Based on the above analysis, the design of the polyurea continuous fiber reinforced layer 3 of the present application plays a key role in resisting water environmental stress degradation.

[0110] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, and are not intended to limit the present application; although the present application has been described in detail with reference to the above embodiments, those skilled in the art should understand that the technical solutions recorded in the above embodiments can be modified, or some or all of the technical features can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A method of forming a corrosion protection layer for a pressure hull section of a composite material, the method comprising: It comprises the following steps: ​ S1) coating epoxy resin on the surface of the composite pressure cabin section (1) to form a waterproof layer (2); S2) mixing polyurea resin and volatile solvent type polymerization inhibitor to obtain an impregnating solution, impregnating continuous fibers or fabrics in the impregnating solution, after impregnation, pulling and winding on the waterproof layer (2) to form a polyurea continuous fiber reinforced layer (3), and irradiating by heat during winding; the impregnated continuous fibers or fabrics are heated before winding on the waterproof layer (2), and the product is cured after winding; S3) spraying polyurea on the surface of the polyurea continuous fiber reinforced layer (3) and heating and curing to form a polyurea layer (4) on the polyurea continuous fiber reinforced layer.

2. The method of claim 1, wherein: In step S2, the waterproof layer (2) is irradiated before winding on the waterproof layer (2), so that the surface temperature of the waterproof layer (2) reaches 40-50℃, and the continuous fibers or fabrics are wound and continuously irradiated by heat.

3. The method of claim 1, wherein: The pulling speed in step S2 is 0.5-1.0 m / s.

4. The method of claim 1, wherein: The volatile solvent type polymerization inhibitor comprises one of ethyl acetate, acetone and anhydrous ethanol.

5. The method of claim 1, wherein: The winding angle of the continuous fibers or fabrics is ±45°.

6. The method of claim 1, wherein: The thickness of the polyurea continuous fiber reinforced layer (3) is 0.5-2 mm.

7. The method of claim 1, wherein: The thickness of the waterproof layer (2) is 1-2 mm, and the thickness of the polyurea layer (4) is 0.5-2 mm.

8. The method of claim 1, wherein: In step S2, after winding the impregnated continuous fibers or fabrics, the polyurea continuous fiber reinforced layer is observed, and after the surface of the polyurea continuous fiber reinforced layer (3) is not sticky and the impregnating solution does not fall off, the product is transferred to the curing oven for curing.

9. The method of claim 1, wherein: The curing temperature in step S3 is 40-50℃.

10. A corrosion protection layer for a composite pressure hull section, obtained by a method according to any one of claims 1 to 9, characterized in that: The surface of the composite pressure cabin section (1) comprises, from inside to outside, the waterproof layer (2), the polyurea continuous fiber reinforced layer (3) and the polyurea layer (4).

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