Carbon fiber cold chain air duct and preparation method thereof

Abstract

The invention relates to the technical field of air ducts, and provides a carbon fiber cold chain air duct and a preparation method thereof. The carbon fiber cold chain air duct is prepared from the following raw materials in parts by weight: 60-80 parts of carbon fibers, 25-35 parts of epoxy resin, 3-5 parts of modified hollow glass beads, 8-10 parts of a curing agent and 3-5 parts of a coupling agent, wherein the modified hollow glass beads are obtained by modifying hollow glass beads with an ethyl hydroxybenzoate compound. According to the technical scheme, the problem that in the prior art, the strength of a carbon fiber cold chain air duct is insufficient is solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of air duct, in particular, relates to a kind of carbon fiber cold chain air duct and preparation method thereof. BACKGROUND

[0002] In the air duct system of cold chain transportation and related refrigeration equipment, the performance of the material plays a crucial role in the overall efficiency of the system. Traditional air duct materials, such as aluminum plates, are too heavy, and in areas such as rail transportation where weight reduction is highly desired, they are not conducive to achieving the goal of lightweight vehicles, thus affecting energy utilization efficiency and operating costs. Carbon fiber, as a new high-performance material, is gradually being applied in the field of air ducts. Compared with traditional materials, it has outstanding advantages: low density, light weight, and air ducts made of carbon fiber can effectively reduce the weight of the system. In addition, carbon fiber has excellent thermal insulation performance, which can maintain the stability of the air temperature in the air duct, reduce the loss of cold energy, and improve the energy utilization efficiency of the cold chain system. However, carbon fiber has insufficient strength, and in special working conditions where the strength of the air duct is required, such as under high pressure, frequent airflow impact or complex mechanical vibration, the existing carbon fiber air duct may deform or even be damaged, making it difficult to fully meet the demand. Therefore, it is necessary to propose a carbon fiber cold chain air duct with high mechanical strength and a preparation method thereof. SUMMARY

[0003] The present application proposes a kind of carbon fiber cold chain air duct and preparation method thereof, solve the problem of insufficient strength of carbon fiber cold chain air duct in prior art.

[0004] The technical solutions of the present application are as follows: The present application proposes a kind of carbon fiber cold chain air duct, which comprises the following components by weight: carbon fiber 60~80 parts, epoxy resin 25~35 parts, modified hollow glass microspheres 3~5 parts, curing agent 8~10 parts, coupling agent 3~5 parts; The modified hollow glass microspheres are obtained by modifying hollow glass microspheres with hydroxybenzoic acid ethyl ester compounds.

[0005] As a further technical solution, the mass ratio of hollow glass microspheres and hydroxybenzoic acid ethyl ester compounds in the raw material of the modified hollow glass microspheres is 85:6~9.

[0006] When the mass ratio of the hollow glass microbeads and the ethyl hydroxybenzoate compound in the carbon fiber cold chain air duct is less than 85:6, the excess ethyl hydroxybenzoate compound will form an excess adsorption layer on the surface of the microbeads, which not only causes waste of the modifier, but also weakens the compatibility of the microbeads and the epoxy resin matrix.

[0007] As a further technical solution, the ethyl hydroxybenzoate compound includes one or more of 3-ethyl hydroxybenzoate, dihydroxybenzoic acid ethyl ester, and 2,4,6-trihydroxybenzoic acid ethyl ester.

[0008] As a further technical solution, the diameter of the hollow glass microbeads is 10-100 μm.

[0009] When the diameter of the hollow glass microbeads is greater than 100 μm, the dispersion difficulty in the epoxy resin matrix is significantly increased, and agglomeration is prone to occur, resulting in the formation of stress concentration points in the carbon fiber cold chain air duct composite material, and reducing the mechanical properties of the material. When the diameter of the hollow glass microbeads is less than 10 μm, the specific surface area of the microbeads is too large, and the surface energy is extremely high. In the mixing process, agglomeration is more likely to occur, and it is difficult to uniformly disperse in the matrix. The existence of the agglomerates will destroy the continuity of the carbon fiber cold chain air duct composite material, resulting in a decrease in the mechanical properties. When the diameter of the hollow glass microbeads is in the range of 10-100 μm, a certain specific surface area can be ensured to enhance the interfacial bonding with the epoxy resin matrix, and the stress can be effectively transmitted through uniform dispersion, thereby improving the mechanical properties of the carbon fiber cold chain air duct composite material.

[0010] As a further technical solution, the preparation method of the modified hollow glass microbeads includes the following steps: dispersing the ethyl hydroxybenzoate compound in anhydrous ethanol, then adding the hollow glass microbeads and mixing for 4 h, and drying to obtain the modified hollow glass microbeads; wherein the mass ratio of the hollow glass microbeads to the ethyl hydroxybenzoate compound is 85:6-9, and the mass-volume ratio of the hollow glass microbeads to the anhydrous ethanol is 1 g:7 mL.

[0011] As a further technical solution, the raw material of the carbon fiber cold chain air duct further includes 10-20 parts of a flame retardant; and the preparation method of the flame retardant includes the following steps: adding aluminum hydroxide and 3,4-dibromobenzoic acid to a solvent, mixing, and drying to obtain the flame retardant.

[0012] 3,4-dibromobenzoic acid and aluminum hydroxide are mixed and added to the carbon fiber cold chain air duct as a flame retardant, on the one hand, 3,4-dibromobenzoic acid can form a connection with aluminum hydroxide through hydrogen bonding, improving the dispersibility of aluminum hydroxide, on the other hand, the bromine element of 3,4-dibromobenzoic acid can generate bromine radicals at high temperature, capture active radicals in combustion to block the chain reaction, and also promote the carbonization of the surface of the carbon fiber cold chain air duct, physically isolate heat and oxygen, 3,4-dibromobenzoic acid and aluminum hydroxide as a flame retardant can further improve the flame retardant effect of the flame retardant, thereby further improving the flame retardant performance of the carbon fiber cold chain air duct.

[0013] As a further technical solution, the particle size of aluminum hydroxide in the raw material of the flame retardant is 10-20 μm.

[0014] As a further technical solution, the curing agent includes one or more of phthalic anhydride, maleic anhydride, and methylhexahydrophthalic anhydride.

[0015] As a further technical solution, the coupling agent includes one or more of silane coupling agent KH-560, silane coupling agent KH-570, and silane coupling agent KH-580.

[0016] The present application also proposes a preparation method of a carbon fiber cold chain air duct, comprising the following steps: S1, the components are mixed uniformly and then densified to obtain a mixture; S2, the mixture is introduced into a mold and pressure formed to obtain a carbon fiber cold chain air duct.

[0017] As a further technical solution, in step S1, the temperature during densification is 100-120℃, for example, it can be 100℃, 110℃, or 120℃, and the time is 10-15 min, for example, it can be 10 min, 13 min, or 15 min; As a further technical solution, in step S2, the pressure for pressure forming is 0.4-0.7 MPa, preferably 0.5 MPa.

[0018] The working principle and beneficial effects of the present application are: The carbon fiber cold chain air duct prepared by the application significantly improves the mechanical strength of the carbon fiber cold chain air duct by adding hollow glass microspheres modified by ethyl 3-hydroxybenzoate. In the prior art, hollow glass microspheres are often added as resin matrix reinforcing fillers to improve the mechanical strength of the carbon fiber cold chain air duct, but the hollow glass microspheres are prone to agglomeration and difficult to disperse uniformly, which leads to the failure of the reinforcing effect. The application adopts ethyl 3-hydroxybenzoate to modify the surface of the hollow glass microspheres, which effectively improves the dispersibility of the hollow glass microspheres in the resin matrix and significantly inhibits the agglomeration phenomenon. The modified hollow glass microspheres can be more uniformly distributed in the carbon fiber cold chain air duct material system, so that the reinforcing effect can be more fully exerted, and the mechanical strength of the carbon fiber cold chain air duct can be further improved. DETAILED DESCRIPTION

[0019] The technical solutions in the embodiments of the application will be clearly and completely described below with reference to the embodiments of the application. Obviously, the described embodiments are only part of the embodiments of the application, rather than all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the application.

[0020] In the following examples and comparative examples, the carbon fiber has a diameter of 75 nm and a length of 6 μm, which is purchased from Henan Kleywin Nanometer Carbon Material Co., Ltd.; the epoxy resin has a model number of E-44; the hollow glass microspheres have a particle size of 20 μm; and the aluminum hydroxide has a particle size of 15 μm.

[0021] Example 1 A preparation method of a carbon fiber cold chain air duct, comprising the following steps: S1, uniformly mixing 60 parts of carbon fiber, 25 parts of epoxy resin, 3 parts of modified hollow glass microspheres, 8 parts of phthalic anhydride and 3 parts of silane coupling agent KH-560, and then densifying, wherein the temperature is 110 ℃ and the time is 13 min during the densifying to obtain a mixture; S2, introducing the mixture into a mold, and then placing the mold into a hot press tank to be press-formed under a pressure of 0.5 MPa to obtain a carbon fiber cold chain air duct; A preparation method of modified hollow glass microspheres, comprising the following steps: dispersing ethyl 3-hydroxybenzoate in anhydrous ethanol, then mixing the hollow glass microspheres for 4 h, and then drying to obtain the modified hollow glass microspheres; wherein the mass ratio of the hollow glass microspheres to ethyl 3-hydroxybenzoate is 85:6, and the mass-to-volume ratio of the hollow glass microspheres to anhydrous ethanol is 1 g:7 mL.

[0022] Example 2 The difference between Example 2 and Example 1 is that, in Example 2, the carbon fiber cold chain air duct is prepared from the following raw materials by weight: 70 parts of carbon fiber, 30 parts of epoxy resin, 4 parts of modified hollow glass microspheres (same as in Example 1), 9 parts of maleic anhydride, and 4 parts of silane coupling agent KH-570.

[0023] Example 3 The difference between Example 3 and Example 1 is that, in Example 3, the carbon fiber cold chain air duct is prepared from the following raw materials by weight: 80 parts of carbon fiber, 35 parts of epoxy resin, 5 parts of modified hollow glass microspheres (same as in Example 1), 10 parts of methylhexahydrophthalic anhydride, and 5 parts of silane coupling agent KH-580.

[0024] Example 4 The difference between Example 4 and Example 2 is that, in Example 4, ethyl 3-hydroxybenzoate is replaced with an equal amount of ethyl dihydroxybenzoate.

[0025] Example 5 The difference between Example 5 and Example 2 is that, in Example 5, ethyl 3-hydroxybenzoate is replaced with an equal amount of ethyl 2,4,6-trihydroxybenzoate.

[0026] Example 6 The difference between Example 6 and Example 4 is that, in Example 6, the mass ratio of hollow glass microspheres to ethyl dihydroxybenzoate is 85:7.

[0027] Example 7 The difference between Example 7 and Example 4 is that, in Example 7, the mass ratio of hollow glass microspheres to ethyl dihydroxybenzoate is 85:9.

[0028] Example 8 A method for preparing a carbon fiber cold chain air duct, comprising the following steps: S1, uniformly mixing 70 parts of carbon fiber, 30 parts of epoxy resin, 4 parts of modified hollow glass microspheres (same as in Example 2), 9 parts of maleic anhydride, 4 parts of silane coupling agent KH-570, and 15 parts of a flame retardant, and then densifying, with a temperature of 110°C and a time of 13 minutes, to obtain a mixture; S2, introducing the mixture into a mold, placing the mold in a hot press tank, and then pressure forming under a pressure of 0.5 MPa to obtain a carbon fiber cold chain air duct; A method for preparing a flame retardant, comprising the following steps: adding 80 parts of aluminum hydroxide and 3 parts of 3,4-dibromobenzoic acid to 100 parts of ethanol, mixing for 2.5 hours, and then drying to obtain the flame retardant.

[0029] Example 9 The difference between Example 9 and Example 8 is that only aluminum hydroxide is used as the flame retardant in this example.

[0030] Example 10 The difference between Example 10 and Example 8 is that 3,4-dibromobenzoic acid is replaced by an equal amount of silane coupling agent KH-560.

[0031] Comparative Example 1 The difference between Comparative Example 1 and Example 2 is that the modified hollow glass microbeads are replaced by an equal amount of hollow glass microbeads.

[0032] The carbon fiber cold chain air ducts in Examples 1-10 and Comparative Example 1 are tested according to the following method: 1. Mechanical strength test: tensile strength test according to standard GB / T 1447-2005 "Fiber Reinforced Plastics Tensile Property Test Method"; 2. Flame retardant performance test: test according to standard TB / T3138-2018 "Flame Retardant Technical Requirements for Materials for Rolling Stock"; The test results are shown in Tables 1-2: Table 1 Mechanical strength test results of carbon fiber cold chain air duct

[0033] As shown in the data in Table 1, the carbon fiber cold chain air duct prepared by the present application has high mechanical strength. Comparative Examples 1-7 show that the addition of hydroxybenzoic acid ethyl ester modified hollow glass microbeads significantly improves the tensile strength of the carbon fiber cold chain air duct.

[0034] Table 2 Flame retardant performance test results of carbon fiber cold chain air duct

[0035] As shown in the data in Table 2, the carbon fiber cold chain air duct prepared by the present application has good flame retardant performance. Comparative Examples 2, 8-10 show that the addition of the flame retardant composed of aluminum hydroxide and 3,4-dibromobenzoic acid significantly reduces the afterburning time and burning damage length of the carbon fiber cold chain air duct, improving the flame retardant performance of the carbon fiber cold chain air duct.

[0036] The above is only a preferred embodiment of the present application and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included within the scope of protection of the present application.

Claims

1. A carbon fiber cold chain air duct, characterized by, The raw material comprises the following components by weight: carbon fiber 60-80 parts, epoxy resin 25-35 parts, modified hollow glass microbeads 3-5 parts, curing agent 8-10 parts, coupling agent 3-5 parts; The modified hollow glass microbeads are hollow glass microbeads modified by a hydroxybenzoic acid ethyl ester compound.

2. A carbon fiber cold chain air duct according to claim 1, wherein, The mass ratio of the hollow glass microbeads to the hydroxybenzoic acid ethyl ester compound in the raw material of the modified hollow glass microbeads is 85:6-9.

3. A carbon fiber cold chain air duct according to claim 1, wherein, The hydroxybenzoic acid ethyl ester compound comprises one or more of 3-hydroxybenzoic acid ethyl ester, dihydroxybenzoic acid ethyl ester, and 2,4,6-trihydroxybenzoic acid ethyl ester.

4. A carbon fiber cold chain air duct according to claim 1, wherein, The hollow glass microbeads have a diameter of 10-100 μm.

5. A carbon fiber cold chain air duct according to claim 1, wherein, The raw material of the carbon fiber cold chain air duct further comprises 10-20 parts of a flame retardant. The preparation method of the flame retardant comprises the following steps: adding aluminum hydroxide and 3,4-dibromobenzoic acid to a solvent, mixing, drying, and obtaining the flame retardant.

6. A carbon fibre cold chain air duct according to claim 5, wherein, The particle size of the aluminum hydroxide in the raw material of the flame retardant is 10-20 μm.

7. A carbon fiber cold chain air duct according to claim 1, wherein, The curing agent comprises one or more of phthalic anhydride, maleic anhydride, and methylhexahydrophthalic anhydride.

8. A carbon fiber cold chain air duct according to claim 1, wherein, The coupling agent comprises one or more of silane coupling agent KH-560, silane coupling agent KH-570, and silane coupling agent KH-580.

9. A method for producing a carbon fiber cold chain air duct, for producing the carbon fiber cold chain air duct according to any one of claims 1 to 8, characterized by, The method comprises the following steps: S1, uniformly mixing the components and then densifying to obtain a mixture; S2, introducing the mixture into a mold, and then performing pressure molding in a hot press tank to obtain the carbon fiber cold chain air duct.

10. The method for preparing a carbon fiber cold chain air duct according to claim 9, characterized in that, In step S2, the pressure of the pressure molding is 0.4-0.7 MPa.

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