Carbon fiber foam sandwich composite flame-retardant material and preparation method thereof

Abstract

The invention relates to a carbon fiber foam sandwich composite flame-retardant material and a preparation method thereof, and belongs to the technical field of fire prevention and heat insulation. The material comprises a foam core material, a carbon fiber cloth layer is laid on the outer side of the foam core material according to a set sequence, a fireproof material layer is laid on the outer side of carbon fiber cloth according to a set sequence, and the carbon fiber cloth layer and the fireproof material layer are filled with epoxy resin. The volume ratio of the epoxy resin is 50-55%; in the carbon fiber foam sandwich composite flame-retardant material, the epoxy resin accounts for 50-55% by mass; the fireproof material comprises one or more of a fiber material and a porous material; the carbon fiber cloth layer comprises a plurality of layers of carbon fiber cloth. The fireproof fiber material layer is additionally arranged on the outer side of the carbon fiber cloth layer, so that the flame retardant grade of the product can be further improved on the premise of fully retaining the advantages of 94V0-grade epoxy resin; and the method is suitable for a VARI forming method, and efficient batch production of high-flame-retardant-grade products can be achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of fire prevention and heat insulation, and particularly relates to a carbon fiber foam sandwich composite flame retardant material and a preparation method thereof. Background Art

[0002] The information disclosed in this background technology section is only intended to enhance the understanding of the overall background of the invention, and should not necessarily be regarded as an admission or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art.

[0003] VARI (Vacuum Assisted Resin Infusion) is a composite material molding technology. This process uses the flow and penetration of resin under vacuum pressure to impregnate fibers and fabrics, and solidifies and molds under vacuum pressure. The advantage is that the product has a lower porosity and a simple manufacturing method.

[0004] Epoxy resin material with a flame retardant grade of 94V0 is a common flame retardant resin material with the advantages of good mechanical properties, low cost, and a wide range of application scenarios. It generally does not require the addition of halogen and is environmentally friendly.

[0005] Some components of rail vehicles are different from common structural reinforcements such as panels. They take into account both functionality and fire safety. For example, the flame retardant level of the driver's cab shell is required to reach the HL2 level of R17 materials in the EN45545-2 standard. The current preparation method mostly uses prepreg. If the VARI process can be used for production, the process will be significantly simplified and production efficiency will be improved. However, the VARI process faces many challenges in the preparation of these components. For example, in order to ensure the effective filling of the resin in the VARI process, the resin content in the product needs to reach 50-55%. Such a high resin content is not conducive to flame retardancy, making it difficult to achieve the set flame retardant level; if the flame retardant level is optimized by reducing the resin content, the effective infusion of the resin in the VARI process cannot be guaranteed; if the 94V0 grade epoxy resin material is improved, such as adding flame retardant particles, the viscosity of the epoxy resin will be significantly increased, not only the implementation of the VARI process cannot be guaranteed, but also the original advantages of the resin material may be lost.

[0006] Therefore, how to use the VARI process to efficiently mass-produce products with high flame retardancy is a technical problem that technicians in this field urgently need to solve. Summary of the invention

[0007] In view of the current technical status, the purpose of the present invention is to provide a carbon fiber foam sandwich composite flame retardant material and a preparation method, which can achieve the flame retardant grade requirement of EN45545 R17 HL2 by using 94V0 flame retardant epoxy resin.

[0008] In order to achieve the above object, the technical solution of the present invention is:

[0009] In a first aspect, a carbon fiber foam sandwich composite flame retardant material comprises a foam core material, a carbon fiber cloth layer is laid on the outside of the foam core material in a set order, a fireproof material layer is laid on the outside of the carbon fiber cloth in a set order, and the carbon fiber cloth layer and the fireproof material layer are filled with epoxy resin;

[0010] In the carbon fiber foam sandwich composite flame retardant material, the mass proportion of epoxy resin is 50-55%; the thickness of the fireproof material layer is 0.2-0.5 mm, and the fireproof material includes one or more of fiber materials and porous materials; the thickness of the carbon fiber cloth layer is 1.2-2.5 mm, including multiple layers of carbon fiber cloth.

[0011] Optionally, the flame retardant grade of the epoxy resin is 94V0, and the flame retardant grade of the carbon fiber foam sandwich composite flame retardant material is not lower than the HL2 grade of R17 material in the EN45545-2 standard.

[0012] Optionally, the fireproof material layer includes one or more layers of fireproof material, and the thickness of a single layer of fireproof material is 0.2 to 0.3 mm.

[0013] Optionally, the carbon fiber cloth includes one or more of carbon fiber unidirectional cloth and carbon fiber biaxial cloth, and the thickness of a single layer of carbon fiber cloth is 0.2-0.3 mm; the carbon fiber unidirectional cloth adopts T300-T800 unidirectional carbon fiber, and the carbon fiber biaxial cloth adopts ±45° biaxial T300-T800 carbon fiber cloth; they are common materials on the market; preferably, carbon fiber unidirectional cloth and / or carbon fiber biaxial cloth made of T300, T700 or T800 carbon fiber are selected.

[0014] Optionally, the angle difference between the ply directions of adjacent carbon fiber cloths is 45° or 90°; the high strength and light weight requirements of the product are achieved through the set plying method.

[0015] Optionally, the foam core material includes PET foam with a thickness of 10 to 20 mm; this material will also absorb epoxy resin to achieve a close connection with the external carbon fiber cloth layer to support the product shape.

[0016] Optionally, the viscosity of the epoxy resin is 300 to 800 mPa.s, including resin and curing agent in a mass ratio of (5 to 6): 1, so as to meet the requirements of the VARI process for resin viscosity; avoid problems such as incomplete wetting, bubble retention or uneven resin distribution, so as to give full play to the advantages of the VARI process and achieve efficient mass production.

[0017] There are sufficient gaps inside the fireproof material for epoxy resin to fill, so that the fireproof material and the internal carbon fiber cloth are bonded together, and the surface of the fireproof material is shaped into a smooth surface by epoxy resin, which can realize subsequent surface treatment processes; the thickness of the fireproof material layer is 0.2-0.4mm; the fireproof material layer can effectively block heat. Although it is filled with epoxy resin, the epoxy resin and the fireproof material form a composite material, which can improve the flame retardant level of the product, thereby making the flame retardant level of the product higher than the flame retardant effect of the epoxy resin; the carbon fiber cloth is used to provide the structural strength of the product, and the epoxy resin can block the contact between the carbon fiber and the air, thereby improving the performance of the carbon fiber in a high temperature environment.

[0018] In a second aspect, a method for preparing a carbon fiber foam sandwich composite flame retardant material comprises the following steps:

[0019] S1. Arrange the foam core material, lay the carbon fiber cloth, and lay the fireproof felt in the mold in the order of covering the outer side of the foam core material with the carbon fiber cloth and covering the outer side of the carbon fiber cloth with the fireproof felt;

[0020] S2. Place the mold and the prepared raw materials into a vacuum bag, evacuate the bag and maintain the pressure for 10 to 15 minutes;

[0021] S3, pouring the prepared epoxy resin into the vacuum bag at a volume ratio of 50-55%, then heating to a set temperature and keeping the temperature to cure, to obtain a product.

[0022] Optionally, in S2, the vacuum pressure after vacuuming is not less than 0.085 MPa.

[0023] Optionally, in S3, the temperature is raised to 80-85 degrees Celsius at a rate of 2°C / min, and the temperature is maintained and cured for 2-3 hours.

[0024] In a third aspect, the carbon fiber foam sandwich composite flame retardant material is used in the outer shell of a driver's cab of a rail vehicle.

[0025] The beneficial effects of the present invention are:

[0026] 1. The present invention provides a carbon fiber foam sandwich composite flame retardant material, which uses epoxy resin with good comprehensive performance and has been widely used as a raw material, adds a fireproof material layer on the outside of the carbon fiber cloth layer, and allows the epoxy resin to fully infiltrate the carbon fiber cloth layer and the fireproof material layer to form a composite material as a whole, which can further improve the flame retardant grade of the product while fully retaining the advantages of 94V0 grade epoxy resin; and is suitable for VARI molding method, and can achieve efficient mass production of high flame retardant grade products.

[0027] 2. The present invention adopts the VARI molding method, which only requires a single-sided rigid mold. It can not only manufacture a structure with uneven thickness according to the shape of the foam core material, but also the one-piece molding process further ensures the integrity of the material, making the material suitable for products with high flame retardancy such as the driver's cab shell. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0029] Figure 1 This is a flow chart of the preparation method of the carbon fiber foam sandwich composite flame retardant material in Example 1. DETAILED DESCRIPTION

[0030] It should be noted that the following detailed descriptions are exemplary and are intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0031] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0032] Example 1

[0033] A carbon fiber foam sandwich composite flame retardant material, comprising a foam core material, a carbon fiber cloth layer is laid on the outside of the foam core material in a set order, a fireproof material layer is laid on the outside of the carbon fiber cloth layer in a set order, and the carbon fiber cloth layer and the fireproof material layer are filled with epoxy resin;

[0034] In the carbon fiber foam sandwich composite flame retardant material, the epoxy resin accounts for 55% by mass;

[0035] The flame retardant grade of epoxy resin is 94V0, and the viscosity of the epoxy resin after preparation is 280mPa.s. It is a common product on the market; 94V0 is a grade in the UL94 standard and belongs to the V-0 level of the vertical burning test.

[0036] The fireproof material layer uses two layers of fireproof fiber felt with a thickness of 0.2mm.

[0037] The carbon fiber cloth layer includes multiple layers of carbon fiber cloth, wherein the carbon fiber unidirectional cloth adopts T300 unidirectional carbon fiber cloth; and the carbon fiber biaxial cloth adopts ±45° biaxial T300 carbon fiber cloth.

[0038] The laying order of the fireproof fiber felt and the carbon fiber cloth is shown in Table 1, and a structure is formed in which the carbon fiber cloth is coated on the outside of the foam core material, and the fireproof fiber felt is coated on the outside of the carbon fiber cloth.

[0039] Table 1

[0040] Serial number Lamination angle 1 Fireproof materials / 2 Fireproof materials / 3 Carbon fiber biaxial fabric 0 4 Carbon fiber unidirectional fabric 45 5 Carbon fiber unidirectional fabric 0 6 Carbon fiber unidirectional fabric 45 7 Carbon fiber unidirectional fabric 90 8 Carbon fiber unidirectional fabric 0 9 Foam / 10 Carbon fiber unidirectional fabric 0 11 Carbon fiber unidirectional fabric 45 12 Carbon fiber unidirectional fabric 90 13 Carbon fiber unidirectional fabric 0 14 Carbon fiber unidirectional fabric 45 15 Carbon fiber biaxial fabric 0 16 Fireproof materials / 17 Fireproof materials /

[0041] The foam core material is PET foam with a thickness of 17mm and a density of 100g / cm 3 , used to support the product shape.

[0042] The preparation method of the carbon fiber foam sandwich composite flame retardant material of this embodiment is as follows Figure 1 As shown, the following steps are included:

[0043] S0. Clean the mold and apply the release agent three times on the mold surface to facilitate demolding; process the foam material into a set shape to become a foam core material; cut the carbon fiber unidirectional cloth, carbon fiber biaxial cloth and fireproof fiber felt material into a size of 850×850 (mm) as raw materials to complete the preparation work.

[0044] S1. According to the plying order and plying angle shown in Table 1, the foam core material is arranged in the mold, the carbon fiber unidirectional cloth / carbon fiber biaxial cloth is laid, and the fireproof felt is laid in the order of covering the outer side of the foam core material with the carbon fiber cloth, and covering the outer side of the carbon fiber cloth with the fireproof felt.

[0045] S2. According to the VARI molding method, lay the demoulding cloth, guide medium and vacuum mold bag on the outside of the mold and the prepared raw material, and install the required injection hose and exhaust pipe and other devices, evacuate to a vacuum pressure of about 0.085MPa and maintain the pressure for 10 to 15 minutes.

[0046] S3. Pour the prepared epoxy resin into the vacuum bag at a volume ratio of 55% to fully fill the carbon fiber material layer, the fireproof material layer and the foam core material with the epoxy resin. Then, heat it to 80°C at a rate of 2°C / min and keep it warm for 2 hours.

[0047] S4. After natural cooling, the film is removed to obtain a carbon fiber foam sandwich composite flame retardant material product.

[0048] Comparative Example 1

[0049] This comparative example provides a carbon fiber foam sandwich composite flame retardant material, comprising a foam core material, a carbon fiber cloth layer is laid on the outside of the foam core material in a set order, and the carbon fiber cloth layer is filled with epoxy resin;

[0050] In the carbon fiber cloth layer, the volume proportion of epoxy resin is 55%;

[0051] The epoxy resin is the same commercially available product as in Example 1.

[0052] The carbon fiber cloth layer includes multiple layers of carbon fiber cloth, and the specifications of the carbon fiber unidirectional cloth and the carbon fiber biaxial cloth are the same as those in Example 1.

[0053] The laying order of the carbon fiber cloth is as shown in Table 1, but the fireproof material in Table 1 is replaced by carbon fiber cloth, and the thickness of the replaced carbon fiber cloth layer is the same as that of the fireproof material layer in Example 1, so that the outer dimensions of the prepared product are the same as those in Example 1.

[0054] The difference between Comparative Example 1 and Example 1 is that no fireproof material is added, and other raw materials and preparation methods are the same as those of Example 1. Performance test

[0055] According to R17 in EN45545-2, EN 45545 is a European unified fire safety standard for rail transit vehicles, applicable to trains, subways, light rails and other vehicles. EN 45545-2 is applicable to the evaluation of the combustion performance of materials and components, including HL1, HL2 and HL3 levels. R17 indicates surface material, which is in line with the use of the driver's cab shell of rail vehicles. The test results are shown in Table 2.

[0056] Table 2

[0057]

[0058] The results show that comparative example 1 without adding fireproof material can only reach HL1 standard, while example 1 with adding fireproof material can reach HL2 standard, which meets the flame retardant standard of driver's cab shell in rail transit field.

[0059] The results in Table 2 also show that the flame retardant properties of carbon fiber-resin composite materials are greatly affected by the resin matrix, so those skilled in the art will select a resin matrix with better flame retardant properties or reduce the resin content in order to improve the flame retardant properties of the composite material. However, the viscosity of the resin matrix with better flame retardant properties does not meet the VARI process requirements, and usually other existing 94V0-grade epoxy resins such as toughness and recyclability are sacrificed for flame retardant properties. The excellent performance reduces the comprehensive performance of the obtained product. If the resin content is reduced, it will also be difficult to prepare products with uniform performance and stable quality due to not meeting the VARI process requirements. Therefore, the present invention does not have a technical solution from the perspective of resin, but 94V0-grade epoxy resin is compounded with fireproof materials as the surface layer of carbon fiber-resin composite materials, achieving flame retardant properties better than 94V0-grade epoxy resins, without the need to additionally develop resin materials with higher fireproof grades, and with the existing VARI process requirements, the degree of adaptation is well set, and there is no need to re-explore the processability of new materials.

[0060] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A carbon fiber foam sandwich composite flame retardant material, characterized in that: It comprises a foam core material, a carbon fiber cloth layer is laid on the outside of the foam core material in a set order, a fireproof material layer is laid on the outside of the carbon fiber cloth in a set order, and the carbon fiber cloth layer and the fireproof material layer are filled with epoxy resin; In the carbon fiber foam sandwich composite flame retardant material, the volume proportion of epoxy resin is 50-55%; the thickness of the fireproof material layer is 0.2-0.5 mm, and the fireproof material includes one or more of fiber materials and porous materials; the thickness of the carbon fiber cloth layer is 1.2-2.5 mm, including multiple layers of carbon fiber cloth.

2. The carbon fiber foam sandwich composite flame retardant material according to claim 1, characterized in that: The flame retardant grade of the epoxy resin is 94V0, and the flame retardant grade of the carbon fiber foam sandwich composite flame retardant material is not lower than the HL2 grade of R17 material in the EN45545-2 standard.

3. The carbon fiber foam sandwich composite flame retardant material according to claim 1, characterized in that: The fireproof material layer includes one or more layers of fireproof material, and the thickness of a single layer of fireproof material is 0.2-0.3 mm.

4. The carbon fiber foam sandwich composite flame retardant material according to claim 1, characterized in that: The carbon fiber cloth includes one or more of carbon fiber unidirectional cloth and carbon fiber biaxial cloth; the carbon fiber unidirectional cloth adopts T300-T800 unidirectional carbon fiber, and the carbon fiber biaxial cloth adopts ±45° biaxial T300-T800 carbon fiber cloth; preferably, carbon fiber unidirectional cloth and / or carbon fiber biaxial cloth made of T300, T700 or T800 carbon fiber are selected; Alternatively, the angle difference between the ply directions of adjacent carbon fiber cloths is 45° or 90°.

5. The carbon fiber foam sandwich composite flame retardant material according to claim 1, characterized in that: The foam core material includes PET foam and has a thickness of 10 to 20 mm.

6. The carbon fiber foam sandwich composite flame retardant material according to claim 1, characterized in that: The viscosity of the epoxy resin is 300-800 mPa.s.

7. A method for preparing a carbon fiber foam sandwich composite flame retardant material as claimed in any one of claims 1 to 6, characterized in that: The following steps are involved: S1. Arrange the foam core material, lay the carbon fiber cloth and lay the fireproof material in the mold in the order of covering the outer side of the foam core material with the carbon fiber cloth and covering the outer side of the carbon fiber cloth with the fireproof felt; S2. Place the mold and the prepared raw materials into a vacuum bag, evacuate the bag and maintain the pressure for 10 to 15 minutes; S3, pouring the prepared epoxy resin into the vacuum bag at a volume ratio of 50-55%, then heating to a set temperature and keeping the temperature to cure, to obtain a product.

8. The method for preparing the carbon fiber foam sandwich composite flame retardant material according to claim 7, characterized in that: In S2, the vacuum pressure after evacuation is not less than 0.085MPa.

9. The method for preparing the carbon fiber foam sandwich composite flame retardant material according to claim 7, characterized in that: In S3, the temperature is raised to 80-85°C at a rate of 2°C / min, and the mixture is kept at this temperature for 2-3 hours for curing.

10. Use of the carbon fiber foam sandwich composite flame retardant material according to any one of claims 1 to 6 in the shell of a driver's cab of a rail vehicle.

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