Flame retardant composite structure and method of manufacturing the same

Abstract

The present application belongs to the field of composite materials, and provides a flame-retardant composite material structure and a manufacturing method thereof. By reasonably selecting a high-performance flame-retardant resin, a fiber fabric and a layer design, lightweight structure can be realized while meeting the EN45545 HL3 flame-retardant fireproof grade. By using a low-cost vacuum introduction process for one-time forming, batch production is realized under the premise of ensuring the quality of the structure, the production efficiency is improved, and the manufacturing cost is reduced.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of composite materials, and particularly relates to a flame-retardant composite material structure and a manufacturing method thereof. BACKGROUND

[0002] The information disclosed in this Background section is only for the purpose of increasing the understanding of the general background of the application and does not necessarily constitute an admission by the patent applicant or the patent owner that this information constitutes prior art.

[0003] With the continuous development of rail transit equipment, composite materials have become the preferred material for lightweight design due to their light weight, high specific strength, and large specific stiffness, and are widely selected and applied in different parts of rail transit vehicles. While meeting the lightweight requirements, the rail transit industry also puts forward strict safety performance requirements such as flame retardation, low smoke, and low toxicity for composite materials. The existing patent CN212666873U discloses a fireproof structure of a fiber composite material foam sandwich panel, which wraps metal foil paper on the outer layer of the fiber composite material structure layer and the foam sandwich, which can isolate the external combustion flame propagation path, reduce the oxygen content required for internal material combustion, and achieve the effect of flame retardation or reducing the heat release rate. However, the composite material fireproof structure in this patent cannot be surface treated and is only suitable for non-decorative parts that are not visible to passengers on the vehicle. The existing patent CN110091551B discloses a rail transit interior wall decoration composite material and a preparation method thereof, and the composite material is a sandwich structure of resin-impregnated fiber cloth-composite polyimide fiber honeycomb-resin-impregnated fiber cloth. However, the composite material preparation process in this patent is divided into two steps of honeycomb and composite material forming, which is not one-step forming, and the hot press tank forming process is used, which has high manufacturing cost and is not suitable for mass production. SUMMARY

[0004] To solve the above problems, the present application provides a composite material layup structure suitable for engineering mass production, which ensures the structural performance and realizes the lightweight of the composite material. High-performance flame-retardant liquid resin is used, and the production efficiency is improved and the manufacturing cost is reduced through low-cost vacuum introduction process integrated forming. The flame-retardant performance reaches the effect of EN45545 HL3 grade. The composite material structure can be surface treated after forming to meet the artistic effect, and can be used for manufacturing various external decorative parts of urban rail transit vehicles, such as the driver's cab cover, the front cover of the vehicle head, etc.

[0005] To achieve the above purpose, the present application adopts the following technical solutions:

[0006] In a first aspect of the present application, a manufacturing method of a flame-retardant composite material structure is provided, comprising:

[0007] The fiber fabric composite layer is formed by laying, in the mold, from bottom to top, surface felt, chopped felt, square cloth, continuous felt, square cloth, chopped felt, three-axis cloth, continuous felt, square cloth, chopped felt, three-axis cloth, continuous felt, chopped felt in sequence.

[0008] The liquid resin is injected into the mold by using the vacuum infusion molding method, so that the resin is impregnated into the fiber fabric composite layer, and after the resin is cured, the mold is demolded, and the flame-retardant composite material structure is obtained.

[0009] The laying mainly adopts the design of alternating felt-cloth, and the laying is as shown in the drawing. Figure 1 The surface layer adopts a layer of surface felt with uniformly dispersed fibers, so as to ensure the surface quality effect of the composite material structure, reduce the influence of the cloth pattern on the surface, and improve the surface flatness and smoothness. The chopped felt and the continuous felt are rich in a certain amount of resin, so as to enhance the interlayer force. The fibers in the square cloth and the three-axis cloth are uniformly distributed, and the square cloth and the three-axis cloth have certain gaps, high tensile strength and the characteristics of facilitating rapid resin impregnation. The alternating design of felt-cloth can ensure the close combination of the laying, and is also helpful for the rapid impregnation of the resin during the vacuum infusion molding, so as to avoid the problems of resin shortage, dry spots and insufficient mechanical properties of the composite material structure, and effectively improve the flame-retardant performance of the composite material. After the composite material structure is formed and demolded, the outer surface can be subjected to the treatment of spraying epoxy primer, scraping putty, spraying intermediate paint and spraying top paint in sequence, the surface effect is beautified according to different artistic designs, and the composite material structure is used for vehicle decoration parts.

[0010] In the second aspect of the present application, the flame-retardant composite material structure prepared by the above method is provided.

[0011] The present application provides a composite material laying structure suitable for engineering batch production, which ensures the structural performance and realizes the lightweight of the composite material.

[0012] In the third aspect of the present application, the outer surface of the flame-retardant composite material structure is subjected to the treatment of spraying epoxy primer, scraping putty, spraying intermediate paint and spraying top paint in sequence, the surface effect is beautified according to different artistic designs, and the composite material structure is used for vehicle decoration parts.

[0013] The present application provides a composite material laying structure suitable for low-cost engineering batch production and a manufacturing method, which realizes the lightweight of the composite material and has strong market applicability. The composite material structure of the present application can be used for manufacturing various external decoration parts of urban rail transit vehicles, and has strong market value.

[0014] Advantages of the present application

[0015] (1) The composite material structure of the present application adopts high-performance flame-retardant liquid resin, realizes the lightweight of the composite material through reasonable laying design, and achieves the effect of EN45545 HL3 grade in terms of flame-retardant performance.

[0016] (2) The composite material structure manufacturing adopts low-cost vacuum introduction process integrated forming, improves production efficiency, reduces manufacturing cost, and is suitable for engineering batch production.

[0017] (3) The composite material structure can be surface treated after forming to meet the artistic effect, and is suitable for external decorative parts of urban rail transit vehicles, such as driver's cabin cover, front cover of vehicle head, etc. BRIEF DESCRIPTION OF DRAWINGS

[0018] The drawings accompanying the specification of the present application serve to provide further understanding of the present application, and the exemplary embodiments of the present application and the description thereof serve to explain the present application, and do not constitute an improper limitation on the present application.

[0019] Figure 1 is a layup design drawing of the present application;

[0020] Figure 2 is a process flow chart of the present application. DETAILED DESCRIPTION

[0021] It should be noted that the following detailed description is exemplary, and is intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used in the present application have the same meaning as generally understood by those skilled in the art to which the present application belongs.

[0022] The composite material of the present application is a layered structure, the matrix uses liquid phenolic resin PF7203 with excellent flame retardant performance, and the reinforcing material uses glass fiber chopped felt, continuous felt, surface felt, square cloth, and axial fabric. The weight specifications of the used fiber fabric are 30g / m 2 , 375g / m 2 , 400g / m 2 , 450g / m 2 , and 900g / m 2 . The glass fiber fabric has high strength and modulus, which ensures the basic mechanical properties of the composite material, and has excellent permeability, which is suitable for liquid resin vacuum introduction forming.

[0023] In some embodiments, the design thickness of the composite material structure is 6mm.

[0024] In some embodiments, the mold is cleaned, waxed, and wiped clean with a soft cloth after airing for 20-30 minutes, and then used.

[0025] In some embodiments, the weight of the used fiber fabric is 30g / m 2 -900g / m 2 , and glue is used to fix the fibers between each layer of fibers.

[0026] In some embodiments, the mold edge retains 50-60 mm of material, the laying layer wrinkle is cut open with scissors, the laying layer lap joint is not more than 20 mm, the corner is compacted to avoid leaving gaps, and the corner is checked after each laying to confirm that there is no gap.

[0027] In some embodiments, after laying the fibers, a release cloth, a flow guide net and a threaded pipe are laid in turn.

[0028] In some embodiments, the threaded pipe is used to lay a back-type closed loop on the flow guide net, the back-type threaded pipe is spaced apart by 300 mm, and the threaded pipe is spaced apart by no more than 450 mm.

[0029] In some embodiments, after laying the threaded pipe, a glue injection seat is placed, and a tee joint pipe is distributed on the front and rear edges of the mold on the mold axis.

[0030] In some embodiments, after placing the tee joint, a vacuum bag film is covered, the mold is sealed with sealing tape around the four sides, and a vacuum system is established.

[0031] In some embodiments, a vacuum operation is performed, the vacuum degree is set to -0.85 to -0.95 MPa, the phenolic resin and the matching curing agent are prepared in proportion, the viscosity of the resin is controlled to be ≤300 mPas, and then the resin is introduced into the mold by means of the vacuum system.

[0032] In some embodiments, the resin is a liquid phenolic resin PF7203.

[0033] In some embodiments, the mold in which the resin is introduced is heated and cured, the temperature is set to 40-60℃ for 4-6 hours, after curing, the mold is cooled and the composite material structure is detected for the Barus hardness before demolding, and the demolding is performed after the target hardness is reached.

[0034] The application will be further described in detail below with reference to specific embodiments, and it should be pointed out that the specific embodiments are an explanation of the application rather than a limitation.

[0035] Embodiment 1

[0036] The composite material structure manufacturing of the application adopts a low-cost vacuum introduction process integrated molding, improves the production efficiency, reduces the manufacturing cost, and is suitable for engineering batch production. The specific manufacturing steps are as follows, and the flow is as shown in Figure 2 .

[0037] 1. Mold preparation: first, use clean cotton yarn to clean the surface of the selected mold. After waxing the auxiliary tool, install it on the mold with screws. After cleaning the surface of the mold, dip the wax in the mold with the cotton yarn and move it in a circular motion from one side of the mold to the other side. The wax is evenly applied and there is no omission. After airing for 25 minutes, wipe it clean with cotton yarn.

[0038] 2. Fiber fabric laying: according to the layer design Figure 1 ), lay the fiber on the mold in order, from bottom to top, and fix the fiber between each layer of fiber using glue spraying. The edge of the mold is required to be reserved with 50 mm of material, the folded layer is cut open and laid flat using scissors, the overlap of the layer is not more than 20 mm, and the corner is compacted using a special tool to avoid leaving a gap, and the corner is checked after each layer is laid.

[0039] 3. Establishing a vacuum system: after laying the fiber in order, lay the release cloth, flow guide net and threaded pipe in sequence. The threaded pipe is used to lay a back-type closed loop on the flow guide net, and the interval between the back-type threaded pipes is 300 mm to ensure smooth flow, and in principle, the interval between the threaded pipes is not greater than 450 mm. After the threaded pipe is laid, the glue injection seat is placed, and the three-way pipe (air extraction interface) is distributed on the front and rear edges of the mold on the central axis of the mold. After placing the three-way pipe, cover the vacuum bag film, seal the mold around with sealing tape, and establish the vacuum system.

[0040] 4. Resin introduction: first, perform vacuum extraction, and set the vacuum degree to (-0.90) MPa, and the vacuum system is sealed well, has no air leakage, and has stable pressure retention. The phenolic resin and the matching curing agent are prepared in proportion, the viscosity of the resin is controlled to be ≤300 mPas, and then the resin is introduced into the mold by means of the vacuum system.

[0041] 5. Curing and demolding: the mold in which the resin is introduced is placed in a drying chamber for heating and curing, and the temperature is set to (50) ℃ for heating for (5) hours. After curing, the mold is removed for standing cooling, the Barre hardness of the composite material structure is detected before demolding, and the mold is demolded after reaching a certain hardness, and finally post-processing can be performed.

[0042] The flame retardant performance of the above-mentioned material is tested, and the results show that the EN45545 HL3 level effect can be achieved.

[0043] Example 2

[0044] The composite material structure manufacturing of the present application adopts a low-cost vacuum introduction process integrated molding, improves the production efficiency, reduces the manufacturing cost, and is suitable for engineering batch production. The specific manufacturing steps are as follows, and the flow is as Figure 2 shown.

[0045] 1. Mold preparation: first, clean the surface of the selected mold with clean cotton yarn. After waxing the auxiliary tool, install it on the mold with screws. After the mold surface is treated clean, dip the wax on the mold with the cotton yarn and move in a circular motion from one side of the mold to the other side, and the wax is required to be evenly applied without omission. After airing for 20 minutes, wipe clean with cotton yarn.

[0046] 2. Fiber fabric laying: According to the layup design ( Figure 1 Lay the fibers onto the mold in sequence, from bottom to top, pressing them firmly and evenly. Use adhesive spray to fix the fibers between each layer. Leave a 50mm edge on the mold. Trim and compact any wrinkles in the layers, ensuring the overlap between layers does not exceed 20mm. Use a special tool to compact the corners to avoid gaps. Check the corners after each layer to ensure there are no gaps.

[0047] 3. Establish a vacuum system: After laying the fibers in sequence, lay the release fabric, flow guide net, and threaded tubes in that order. Use the threaded tubes to lay a closed loop on the flow guide net. To ensure smooth flow, the threaded tubes should be spaced 300mm apart, and ideally, the spacing should not exceed 450mm. After laying the threaded tubes, place the injection base and distribute tee pipes (vacuum ports) along the front and rear edges of the mold along the central axis. After placing the tee pipes, cover with a vacuum bag film and seal the mold with sealing tape to establish a vacuum system.

[0048] 4. Resin Introduction: First, a vacuum operation is performed, with the vacuum negative pressure set at (-0.85) MPa. The vacuum system must be well-sealed, leak-free, and maintain stable pressure. Phenolic resin and matching curing agent are mixed in proportion, with the resin viscosity controlled at ≤300 mPas. Then, the resin is introduced into the mold using the vacuum system.

[0049] 5. Curing and Demolding: Place the mold after resin has been poured into it in a drying chamber for heating and curing. Set the temperature to (40)℃ and heat for (6) hours. After curing, remove the mold and let it cool. Before demolding, test the Barcol hardness of the composite material structure. Demold after it reaches a certain hardness. Finally, post-processing can be performed.

[0050] The flame retardant properties of the above materials were tested, and the results showed that they could achieve the EN45545 HL3 level effect.

[0051] Example 3

[0052] The composite material structure of this invention employs a low-cost vacuum induction process for integrated molding, which improves production efficiency, reduces manufacturing costs, and is suitable for engineering-scale mass production. The specific manufacturing steps are as follows: [Flowchart follows] Figure 2 As shown.

[0053] 1. Mold Preparation: First, use clean cotton yarn to clean the surface of the selected mold. After waxing the auxiliary tooling, install it onto the mold with screws. After cleaning the mold surface, use cotton yarn to apply wax evenly to the mold in a circular motion from one side to the other, ensuring even application without any omissions. Let it dry for 30 minutes, then wipe it clean with cotton yarn.

[0054] 2. Fiber fabric laying: According to the layup design (Figure 1 ), according to the order, lay the fibers on the mold, from bottom to top, and use glue to fix the fibers between each layer of fibers. The edge of the mold is required to be reserved with 50mm material, the folded layer is cut open with scissors, the overlap of the layer is not more than 20mm, the corner is pressed with a special tool to avoid leaving gaps, and the corner is checked after each layer is laid.

[0055] 3. Establishing a vacuum system: after laying the fibers in order, lay the release cloth, flow guide net and threaded pipe in turn. Use the threaded pipe to lay the back type closed loop on the flow guide net, and ensure the smooth flow by spacing the back type threaded pipe 300mm apart, and in principle, the spacing of the threaded pipe is not more than 450mm. After laying the threaded pipe, place the glue injection seat, and distribute the three-way pipe (air extraction interface) on the front and rear edges of the mold on the central axis of the mold. After placing the three-way pipe, cover the vacuum bag film, seal the mold with sealing tape around the four sides, and establish the vacuum system.

[0056] 4. Resin introduction: first, perform the vacuum operation, and set the vacuum degree to (-0.95) MPa. The vacuum system is sealed well, without air leakage, and the pressure is stable. Prepare the phenolic resin and the matching curing agent according to the proportion, control the viscosity of the resin to be less than or equal to 300mPas, and then introduce the resin into the mold by means of the vacuum system.

[0057] 5. Curing and demolding: place the mold with the introduced resin in the drying room for heating and curing, and set the temperature to (60) ℃ for (4) hours. After curing, remove the mold and cool it, detect the bar hardness of the composite material structure before demolding, and demold after reaching a certain hardness. Finally, post-processing can be performed.

[0058] The flame retardant performance of the above material is tested, and the results show that the EN45545 HL3 level effect can be achieved.

[0059] The above only describes the preferred embodiments of the present application and is not used to limit the present application. For those skilled in the art, the present application can have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A method for manufacturing a flame-retardant composite material structure, characterized in that, include: In the mold, surface felt, chopped strand mat, woven fabric, continuous felt, woven fabric, chopped strand mat, triaxial fabric, continuous felt, woven fabric, chopped strand mat, triaxial fabric, continuous felt, chopped strand mat, continuous felt, woven fabric, continuous felt, chopped strand mat, continuous felt, chopped strand mat, and chopped strand mat are laid sequentially from bottom to top to form a fiber fabric composite layer. Liquid resin is injected into a mold using a vacuum infusion molding method to impregnate the fiber fabric composite layer. After the resin cures, the product is demolded to obtain the final product. The weight of the fiber fabric used is 30g / m². 2 ~900g / m 2 Each layer of fiber is fixed with adhesive spray. Leave 50-60mm of material at the edge of the mold. Cut open the wrinkles of the layers with scissors and lay them firmly. The overlap of the layers should not exceed 20mm. The corners should be pressed firmly to avoid leaving gaps. Check the corners after each layer to make sure there are no gaps. The resin is liquid phenolic resin PF7203; After laying the fibers, lay the release fabric, flow guide net, and threaded pipe in sequence; Use threaded pipes to lay a loop-shaped closed loop on the guide net, with the spacing of the threaded pipes not exceeding 450mm. Alternatively, after the threaded pipe is laid, place the injection base, and distribute tee pipes along the front and rear edges of the mold on the central axis of the mold. After placing the T-connector, cover it with a vacuum bag film and seal the mold with sealing tape to establish a vacuum system. Perform a vacuuming operation, setting the vacuum negative pressure to -0.85~-0.95MPa. Mix the phenolic resin and the matching curing agent in proportion, controlling the resin viscosity to ≤300mPas. Then, use the vacuum system to introduce the resin into the mold.

2. The method for manufacturing the flame-retardant composite material structure as described in claim 1, characterized in that, Clean the mold thoroughly, wax it, let it air dry for 20-30 minutes, then wipe it clean with cotton gauze before using it.

3. The method for manufacturing a flame-retardant composite material structure as described in claim 1, characterized in that, After the resin has been poured into the mold, heat it to cure. Set the temperature to 40~60℃ and heat for 4~6 hours. After curing, let the mold cool. Before demolding, test the Barcol hardness of the composite material structure. Demolding is performed after the target hardness is reached.

4. The flame-retardant composite material structure prepared by the method according to any one of claims 1-3.

5. The flame-retardant composite material structure as described in claim 4, characterized in that, The outer surface of the flame-retardant composite material structure is sequentially coated with epoxy primer, putty, intermediate coat, and topcoat. The surface is beautified according to different artistic designs and used for vehicle decoration parts.

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