A composite fiber material for automotive interior panels and its preparation method

Abstract

The present invention relates to a preparation method of a composite fiber material for automobile interior trim panels, which comprises the following steps: (1) uniformly mixing an olefin copolymer rich in terminal bromine, polyvinylpyrrolidone, and a solvent to obtain a spinning dope; injecting it into a hollow fiber spinning spinneret, and simultaneously extruding it and the core liquid in the spinneret central tube into an external coagulation bath to obtain hollow fiber filaments rich in terminal bromine; (2) impregnating it in a mixed solution prepared by compounding 4-(2-epoxyethyloxy)pyridine and toluene, heating and reacting it at an elevated temperature to obtain hollow fiber filaments with surface graft modification treatment; (3) compounding and blending it with modified natural plant fibers, and performing heat treatment at an elevated temperature to obtain a composite fiber material for automobile interior trim panels. The composite fiber material prepared by the present invention not only has excellent mechanical properties and antibacterial properties, but also has good properties such as high and low temperature resistance, stain and aging resistance, and flame retardancy, and can meet the requirements for manufacturing lightweight automobile parts.

Description

Technical Field

[0001] The present invention relates to the technical field of composite fiber materials, and particularly to a composite fiber material for automobile interior trim panels and a preparation method thereof. Background Art

[0002] With the rapid development of the economy and the increasing improvement of people's living standards, automobiles, as a means of transportation for people to travel, have become more and more popular. As one of the important components of automobiles, automobile interior trim panels are usually required to have characteristics such as beauty, softness, comfort, and no peculiar smell. At present, the composite substrates used for manufacturing automobile interior trim panels are gradually being replaced by natural plant fiber composite materials. In the prior art, the patent document (publication number: CN102145553A) discloses an environmentally friendly and recyclable basalt fiber and hemp fiber composite board for automobile interior trim parts, which has the advantages of light weight, low cost, high strength, good toughness, large deformability, high safety, and environmental friendliness and recyclability. However, it is difficult to simultaneously have excellent mechanical properties and antibacterial properties, as well as other comprehensive performance requirements such as high and low temperature resistance, stain resistance, and aging resistance. Summary of the Invention

[0003] In view of the above deficiencies of the prior art, on the one hand, the present invention provides a preparation method of a composite fiber material for automobile interior trim panels to solve the problem that the existing composite fiber materials for automobile interior trim panels cannot simultaneously have excellent mechanical properties and antibacterial properties, as well as other comprehensive performance requirements such as high and low temperature resistance, stain resistance, and aging resistance.

[0004] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0005] A preparation method of a composite fiber material for automobile interior trim panels, the preparation method comprising the following steps:

[0006] (1) Mix an olefin copolymer rich in terminal bromine, polyvinylpyrrolidone, and a solvent evenly, evacuate to remove the air bubbles therein to obtain a spinning dope; inject the spinning dope into a hollow fiber spinning spinneret, and simultaneously extrude the spinning dope and the core liquid in the central tube of the spinneret into an external coagulation bath to obtain hollow fiber filaments rich in terminal bromine. The hollow fiber filaments prepared by the present invention not only contribute to the development of automobile lightweight, but also improve the mechanical properties such as the impact toughness of the composite fiber material.

[0007] (2) Immerse the hollow fiber filaments rich in terminal bromine obtained in step (1) in a mixed solution composed of 4-(2-epoxyethyloxy)pyridine and toluene. After heating and reacting, hollow fiber filaments with surface graft modification treatment are obtained; the surface of the hollow fiber filaments of the present invention is rich in terminal bromine, and the terminal bromine undergoes a substitution reaction with the nitrogen on 4-(2-epoxyethyloxy)pyridine to form pyridinium salt, which helps to improve the antibacterial property of the composite fiber material. At the same time, the epoxyethyl groups carried can further form chemical bonds with the natural plant fibers modified with hydroxyl groups, thereby improving the mechanical properties such as the strength of the composite fiber material.

[0008] (3) Compound and blend the hollow fiber filaments with surface graft modification treatment obtained in step (2) with the modified natural plant fibers. After heating and heat treatment, the composite fiber material for automotive interior panels is obtained.

[0009] Preferably, the mass ratio of the olefin copolymer rich in terminal bromine, polyvinylpyrrolidone, and the solvent is 20-30:15-20:60-80.

[0010] Preferably, the olefin copolymer rich in terminal bromine is obtained by copolymerizing a triazine derivative containing terminal bromine and olefin with a first vinyl halide and a second vinyl halide. Specifically, the triazine derivative containing terminal bromine and olefin is uniformly dispersed in the solvent N,N-dimethylformamide, the first vinyl halide and 1 / 2 portion of the initiator are added, and after stirring and reacting for a certain time, the second vinyl halide and the remaining 1 / 2 portion of the initiator are added. After the reaction is completed, an olefin copolymer rich in terminal bromine is obtained. In the present invention, the first vinyl halide is mainly vinyl fluoride, and the second vinyl halide is vinyl bromide. Through the copolymerization reaction of the triazine derivative containing terminal bromine and olefin with the first vinyl halide and the second vinyl halide, a large number of active bromine end groups are introduced into the polymer side chain. At the same time, the introduction of the fluorine-containing chain segment helps to improve the stain resistance of the composite fiber material, and the introduction of the bromine-containing chain segment helps to improve the flame retardant property of the composite fiber material. The introduction of the triazine derivative chain segment in the present invention also helps to improve the high and low temperature resistance and aging resistance of the composite fiber material.

[0011] Preferably, the preparation method of the triazine derivative containing terminal bromine and olefin is as follows: 1,3,5-triacryloyl hexahydro-1,3,5-triazine is uniformly dispersed in the solvent N,N-dimethylformamide, and bromoolefin is added according to the molar ratio of bromoolefin to 1,3,5-triacryloyl hexahydro-1,3,5-triazine of 2:1. The temperature is raised for reaction for a period of time in an inert atmosphere. After the reaction is completed, the reaction mixture is separated to obtain the triazine derivative containing terminal bromine and olefin. In the present invention, an addition reaction is carried out between two unsaturated double bonds on 1,3,5-triacryloyl hexahydro-1,3,5-triazine and the unsaturated double bond on bromoolefin to obtain a triazine derivative grafted with two terminal bromines and one remaining olefin unsaturated double bond. Among them, the terminal bromine can undergo a substitution reaction with the nitrogen in 4-(2-epoxyethanyloxy)pyridine to obtain a pyridinium salt with epoxyethane, and the remaining one olefin unsaturated double bond can copolymerize with the first vinyl halide and the second vinyl halide.

[0012] Preferably, the bromoolefin is at least one of 4-bromo-1-butene, 3-bromopropene, 3-(2-bromoethoxy)-1-propene, and 5-bromo-1-pentene.

[0013] Preferably, the first vinyl halide is at least one of tetrafluoroethylene, trifluoroethylene, and vinylidene fluoride.

[0014] Preferably, the second vinyl halide is at least one of 1-bromo-1-chloroethylene, 1,2-dibromoethylene, vinyl bromide, and cis-1,2-dibromoethylene.

[0015] Preferably, the core liquid is an aqueous solution of polyethylene glycol with a mass concentration of 5-10%. The flow rate of the core liquid is 5-15 mL / min, the temperature of the core liquid is 20-80 °C, and the spinning speed is 6-12 m / min.

[0016] Preferably, the modification method of the modified natural plant fiber is as follows: The natural plant fiber is successively placed in hydrogen peroxide solutions with mass fractions of 3-7% and 7-15% for ultrasonic-assisted stirring reaction. The reaction temperature is 85-95 °C, and the reaction time is 30-120 min. After the reaction is completed, it is washed with water and dried to obtain a modified natural plant fiber rich in hydroxyl groups on the surface. In the present invention, the surface of the natural plant fiber is hydroxylated by hydrogen peroxide solutions with two different concentrations, high and low, to provide a modified natural plant fiber rich in hydroxyl active sites on the surface, and then through a chemical bond binding method with the surface of the hollow fiber filament subjected to surface graft modification treatment, the stable combination between the composite fibers is realized, thereby improving the service life and service performance of the automotive interior trim panel.

[0017] Another aspect of the present invention is to provide a composite fiber material for an automotive interior trim panel, and the composite fiber material is prepared by using the preparation method of the composite fiber material for an automotive interior trim panel as described above.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0019] The composite fiber material for automotive interior panels of the present invention is obtained by heat treatment after compound spinning of hollow fiber filaments with surface graft modification treatment and modified natural plant fibers. It not only has excellent mechanical properties and antibacterial properties, but also has excellent properties such as high and low temperature resistance, stain resistance and aging resistance, and can meet the requirements for manufacturing lightweight automotive parts. Embodiment

[0020] The following description is used to disclose the present invention so that those skilled in the art can implement the present invention. The preferred embodiments in the following description are only examples, and those skilled in the art can think of other obvious variations. Example 1

[0021] The preparation method of the composite fiber material for automotive interior panels in this embodiment includes the following steps:

[0022] (1) Mix the olefin copolymer rich in terminal bromine, polyvinylpyrrolidone, and the solvent N,N-dimethylformamide evenly, evacuate to remove the bubbles therein to obtain a spinning dope; inject the spinning dope into a hollow fiber spinning nozzle, and simultaneously extrude the spinning dope and the core liquid in the central tube of the nozzle into an external coagulation bath to obtain hollow fiber filaments rich in terminal bromine; the mass ratio of the olefin copolymer rich in terminal bromine, polyvinylpyrrolidone, and N,N-dimethylformamide is 20:15:60. The core liquid is an aqueous solution of polyethylene glycol with a mass concentration of 6%. The core liquid flow rate is 10 mL / min, the core liquid temperature is 60 °C, and the spinning speed is 12 m / min. The spinning temperature of the spinning solution is 80 °C.

[0023] (2) Immerse the hollow fiber filaments rich in terminal bromine obtained in step (1) in a mixed solution composed of 4-(2-epoxyethanyloxy)pyridine and toluene, heat up and react, and the reaction temperature is 95 °C to obtain hollow fiber filaments with surface graft modification treatment; the mass ratio of the hollow fiber filaments rich in terminal bromine, 4-(2-epoxyethanyloxy)pyridine, and toluene is 20:7:100.

[0024] (3) Compound and blend the hollow fiber filaments with surface graft modification treatment obtained in step (2) with modified natural plant fibers, and heat-treat by introducing saturated steam to obtain the composite fiber material for automotive interior panels. The mass ratio of the flame-retardant hollow fiber filaments to the natural plant fiber filaments is 1:1.

[0025] The olefin copolymer rich in terminal bromine is obtained by copolymerizing a triazine derivative containing terminal bromine and olefin with tetrafluoroethylene and vinyl bromide. Specifically, 12.5 parts by weight of 1,3,5-triacryloyl hexahydro-1,3,5-triazine is uniformly dispersed in 100 parts by weight of the solvent N,N-dimethylformamide. 3-bromopropene is added according to the molar ratio of 3-bromopropene to 1,3,5-triacryloyl hexahydro-1,3,5-triazine of 2:1. The reaction is carried out by heating for a certain period of time in an inert nitrogen atmosphere. The reaction temperature is 80 °C and the reaction time is 1.5 h. After the reaction is completed, the reaction mixture is separated to obtain the triazine derivative containing terminal bromine and olefin. Then, 25 parts by weight of the triazine derivative containing terminal bromine and olefin is uniformly dispersed in 100 parts by weight of the solvent N,N-dimethylformamide. 35 parts by weight of tetrafluoroethylene and 0.7 parts by weight of the initiator ammonium persulfate are added. After stirring and reacting for a certain time, 25 parts by weight of vinyl bromide and the remaining 0.7 parts by weight of the initiator ammonium persulfate are added. After the reaction is completed, an olefin copolymer rich in terminal bromine is obtained.

[0026] The modification method of the modified natural plant fiber is as follows: The natural plant fiber is successively placed in hydrogen peroxide solutions with mass fractions of 3% and 7% for ultrasonic-assisted stirring reaction. The reaction temperature is 85 °C and the reaction time is 60 min. After the reaction is completed, it is washed with water and dried to obtain a modified natural plant fiber rich in hydroxyl groups on the surface. Example 2

[0027] The preparation method of the composite fiber material for the automotive interior panel in this example includes the following steps:

[0028] (1) The olefin copolymer rich in terminal bromine, polyvinylpyrrolidone, and the solvent N,N-dimethylformamide are compounded and mixed evenly, and the air bubbles are evacuated by vacuum to obtain a spinning dope. The spinning dope is injected into a hollow fiber spinning spinneret, and the spinning dope and the core liquid in the central tube of the spinneret are simultaneously extruded into an external coagulation bath to obtain hollow fiber filaments rich in terminal bromine. The mass ratio of the olefin copolymer rich in terminal bromine, polyvinylpyrrolidone, and N,N-dimethylformamide is 30:15:80. The core liquid is an aqueous solution of polyethylene glycol with a mass concentration of 8%. The flow rate of the core liquid is 12 mL / min, the temperature of the core liquid is 80 °C, the spinning speed is 8 m / min. The spinning temperature of the spinning solution is 90 °C.

[0029] (2) The hollow fiber filaments rich in terminal bromine obtained in step (1) are impregnated in a mixed solution compounded from 4-(2-epoxyethyloxy)pyridine and toluene, and after heating and reacting, the reaction temperature is 85 °C to obtain hollow fiber filaments with surface graft modification treatment. The mass ratio of the hollow fiber filaments rich in terminal bromine, 4-(2-epoxyethyloxy)pyridine, and toluene is 25:7:100.

[0030] (3) Compound and blend the surface graft-modified hollow fiber filaments obtained in step (2) with modified natural plant fibers, and after heating and treating with saturated steam, obtain the composite fiber material for the automotive interior panel. The mass ratio of the flame-retardant hollow fiber filaments to the natural plant fiber filaments is 2:3.

[0031] The olefin copolymer rich in terminal bromine is obtained by copolymerizing a triazine derivative containing terminal bromine and olefin with trifluoroethylene and 1-bromo-1-chloroethylene. Specifically, first, 12.5 parts by weight of 1,3,5-triacryloyl hexahydro-1,3,5-triazine is uniformly dispersed in 100 parts by weight of the solvent N,N-dimethylformamide, and 4-bromo-1-butene is added according to the molar ratio of 4-bromo-1-butene to 1,3,5-triacryloyl hexahydro-1,3,5-triazine of 5:2. React at an elevated temperature for a period of time in an inert nitrogen atmosphere, the reaction temperature is 80 °C, the reaction time is 2 h. After the reaction is completed, the reaction mixture is separated to obtain the triazine derivative containing terminal bromine and olefin; then, 22 parts by weight of the triazine derivative containing terminal bromine and olefin is uniformly dispersed in 100 parts by weight of the solvent N,N-dimethylformamide, 30 parts by weight of trifluoroethylene and 0.6 parts by weight of the initiator ammonium persulfate are added, and after stirring and reacting for a certain time, 30 parts by weight of 1-bromo-1-chloroethylene and the remaining 0.6 parts by weight of the initiator ammonium persulfate are added. After the reaction is completed, an olefin copolymer rich in terminal bromine is obtained.

[0032] The modification method of the modified natural plant fiber is as follows: Place the natural plant fiber in hydrogen peroxide solutions with mass fractions of 5% and 10% in sequence, and carry out ultrasonic-assisted stirring reaction. The reaction temperature is 85 °C, the reaction time is 120 min. After the reaction is completed, wash with water and dry to obtain the modified natural plant fiber rich in hydroxyl groups on the surface.

[0033] Example 3

[0034] The preparation method of the composite fiber material for the automotive interior panel in this example includes the following steps:

[0035] (1) Compound and mix the olefin copolymer rich in terminal bromine, polyvinylpyrrolidone, and the solvent N,N-dimethylformamide evenly, evacuate the air bubbles in it to obtain a spinning dope; inject the spinning dope into a hollow fiber spinning spinneret, and extrude the spinning dope and the core liquid in the central tube of the spinneret into an external coagulation bath simultaneously to obtain hollow fiber filaments rich in terminal bromine; the mass ratio of the olefin copolymer rich in terminal bromine, polyvinylpyrrolidone, and N,N-dimethylformamide is 30:15:70. The core liquid is an aqueous solution of polyethylene glycol with a mass concentration of 5%. The core liquid flow rate is 6 mL / min, the core liquid temperature is 60 °C, and the spinning speed is 6 m / min. The spinning temperature of the spinning solution is 70 °C.

[0036] (2) Immerse the hollow fiber filaments rich in terminal bromine obtained in step (1) in a mixed solution composed of 4-(2-epoxyethyloxy)pyridine and toluene. After heating and reacting at an elevated temperature, the reaction temperature is 75 °C to obtain hollow fiber filaments with surface graft modification treatment; the mass ratio of the hollow fiber filaments rich in terminal bromine, 4-(2-epoxyethyloxy)pyridine, and toluene is 30:7:100.

[0037] (3) Compound and blend the hollow fiber filaments with surface graft modification treatment obtained in step (2) with modified natural plant fibers. After introducing saturated steam and heating and treating at an elevated temperature, the composite fiber material for automotive interior panels is obtained. The mass ratio of the flame-retardant hollow fiber filaments to natural plant fiber filaments is 3:2.

[0038] The olefin copolymer rich in terminal bromine is obtained by copolymerization reaction of a triazine derivative containing terminal bromine and olefin with vinylidene fluoride and 1,2-dibromoethylene. Specifically, first, 12.5 parts by weight of 1,3,5-triacryloyl hexahydro-1,3,5-triazine is uniformly dispersed in 100 parts by weight of the solvent N,N-dimethylformamide. 3-(2-bromoethoxy)-1-propene is added according to the molar ratio of 3-(2-bromoethoxy)-1-propene to 1,3,5-triacryloyl hexahydro-1,3,5-triazine of 2:1. After heating and reacting for a period of time in a nitrogen inert atmosphere, the reaction temperature is 80 °C, and the reaction time is 2.5 h. After the reaction ends, the reaction mixture is separated to obtain the triazine derivative containing terminal bromine and olefin; then, 20 parts by weight of the triazine derivative containing terminal bromine and olefin is uniformly dispersed in 100 parts by weight of the solvent N,N-dimethylformamide. 25 parts by weight of vinylidene fluoride and 0.5 part by weight of the initiator ammonium persulfate are added. After stirring and reacting for a certain time, 35 parts by weight of 1,2-dibromoethylene and the remaining 0.5 part by weight of the initiator ammonium persulfate are added. After the reaction ends, an olefin copolymer rich in terminal bromine is obtained.

[0039] The modification method of the modified natural plant fiber is as follows: The natural plant fiber is successively placed in hydrogen peroxide solutions with mass fractions of 7% and 15% for ultrasonic-assisted stirring reaction. The reaction temperature is 85 °C, and the reaction time is 30 min. After the reaction ends, it is washed with water and dried to obtain modified natural plant fibers rich in hydroxyl groups on the surface.

[0040] Example 4

[0041] The preparation method of the composite fiber material for automotive interior panels in this example is basically the same as that in Example 1, except that in the preparation method of the composite fiber material in this example, trifluoroethylene is used instead of tetrafluoroethylene for the first halogenated ethylene, cis-1,2-dibromoethylene is used instead of bromoethylene for the second halogenated ethylene, and 5-bromo-1-pentene is used instead of 3-bromopropene for the bromoolefin.

[0042] Example 5

[0043] The preparation method of the composite fiber material for the automotive interior trim panel in this example is basically the same as that in Example 1, except that in the preparation method of the composite fiber material in this example, vinylidene fluoride is used instead of tetrafluoroethylene for the first halogenated ethylene, 1-bromo-1-chloroethylene is used instead of vinyl bromide for the second halogenated ethylene, and 4-bromo-1-butene is used instead of 3-bromopropene for the bromoolefin.

[0044] Example 6

[0045] The preparation method of the composite fiber material for the automotive interior trim panel in this example is basically the same as that in Example 1, except that in the preparation method of the composite fiber material in this example, trifluoroethylene is used instead of tetrafluoroethylene for the first halogenated ethylene, 1,2-dibromoethylene is used instead of vinyl bromide for the second halogenated ethylene, and 3-(2-bromoethoxy)-1-propene is used instead of 3-bromopropene for the bromoolefin.

[0046] The composite fiber materials for the automotive interior trim panel prepared in Examples 1 to 6 were subjected to performance tests, and the performance results are shown in Table 1:

[0047] Table 1

[0048]

[0049] Mechanical property test: The tensile property was tested according to the test standard of GB / T 1040.2-2006. The warp-knitted flame-retardant automotive interior trim panel composite materials prepared in Examples 1-6 were cut into specimens with dimensions of 200 mm × 10 mm × 4 mm, the tensile speed was 50 mm / min, and a CMT4101 type electronic tensile testing machine was used for the test; the notched impact strength was tested according to the test standard of GB / T1843-2008, and an XIJ-5 type simply supported beam impact testing machine was used for the test.

[0050] The antibacterial property test was carried out according to GB15981.

[0051] High and low temperature resistance test: The samples were placed in a low temperature oven at -40 °C and a high temperature oven at 85 °C for 168 h; the high and low temperature resistance performance of the samples was evaluated as qualified if the tensile strength was not less than 95% of the tensile strength of the initial sample.

[0052] Aging resistance test: The samples were placed in a high-pressure accelerated aging test chamber at 105 ± 2 °C for 168 h; the aging resistance performance of the samples was evaluated as qualified if the tensile strength was not less than 90% of the tensile strength of the initial sample.

[0053] Thus, it can be seen that this invention patent has quite significant advantages compared with the currently used technologies. The above has shown and described the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. What is described in the above embodiments and the specification is only the principle of the present invention. Without departing from the spirit and scope of the present invention, various changes and improvements will occur to the present invention, and these changes and improvements all fall within the scope of the present invention claimed.

Claims

1. A preparation method of a composite fiber material for an automotive interior trim panel, characterized in that, the preparation method comprises the following steps: (1) Uniformly mix an olefin copolymer rich in terminal bromine, polyvinylpyrrolidone, and a solvent, evacuate to remove the air bubbles therein to obtain a spinning dope; inject the spinning dope into a hollow fiber spinning nozzle, and simultaneously extrude the spinning dope and the core liquid in the central tube of the nozzle into an external coagulation bath to obtain hollow fiber filaments rich in terminal bromine; (2) Immerse the hollow fiber filaments rich in terminal bromine obtained in step (1) in a mixed solution composed of 4-(2-epoxyethyloxy)pyridine and toluene, heat up and react to obtain hollow fiber filaments with surface graft modification treatment; (3) Compound and blend the hollow fiber filaments with surface graft modification treatment obtained in step (2) with modified natural plant fibers, heat up and perform heat treatment to obtain the composite fiber material for the automotive interior trim panel.

2. The preparation method of the composite fiber material for the automotive interior trim panel as described in claim 1, characterized in that, the mass ratio of the olefin copolymer rich in terminal bromine, polyvinylpyrrolidone, and the solvent is 20 - 30:15 - 20:60 - 80.

3. The preparation method of the composite fiber material for the automotive interior trim panel as described in claim 1, characterized in that, the olefin copolymer rich in terminal bromine is obtained by copolymerization reaction of a triazine derivative containing terminal bromine and olefins with a first vinyl halide and a second vinyl halide.

4. The preparation method of the composite fiber material for the automotive interior trim panel as described in claim 3, characterized in that, the preparation method of the triazine derivative containing terminal bromine and olefins is: uniformly disperse 1,3,5-triacryloylhexahydro-1,3,5-triazine in the solvent N,N-dimethylformamide, add a bromoolefin according to the molar ratio of bromoolefin to 1,3,5-triacryloylhexahydro-1,3,5-triazine of 2:1, heat up and react for a period of time in an inert atmosphere, and separate the reaction mixture after the reaction is completed to obtain the triazine derivative containing terminal bromine and olefins.

5. The preparation method of the composite fiber material for the automotive interior trim panel as described in claim 4, characterized in that, the bromoolefin is at least one of 4-bromo-1-butene, 3-bromopropene, 3-(2-bromoethoxy)-1-propene, 5-bromo-1-pentene.

6. The preparation method of the composite fiber material for the automotive interior trim panel as described in claim 3, characterized in that, the first vinyl halide is at least one of tetrafluoroethylene, trifluoroethylene, vinylidene fluoride.

7. The preparation method of the composite fiber material for the automotive interior trim panel as described in claim 3, characterized in that, the second vinyl halide is at least one of 1-bromo-1-chloroethylene, 1,2-dibromoethylene, vinyl bromide, cis-1,2-dibromoethylene.

8. The preparation method of the composite fiber material for the automotive interior trim panel as described in claim 1, characterized in that, the core liquid is an aqueous solution of polyethylene glycol with a mass concentration of 5 - 10%.

9. The preparation method of the composite fiber material for the automotive interior trim panel as described in claim 1, characterized in that, The modification method of the modified natural plant fiber is as follows: The natural plant fiber is successively placed in hydrogen peroxide solutions with mass fractions of 3-7% and 7-15% for ultrasonic-assisted stirring reaction. The reaction temperature is 85-95 °C, and the reaction time is 30-120 min. After the reaction, it is washed with water and dried to obtain the modified natural plant fiber rich in hydroxyl groups on the surface.

10. A composite fiber material for automotive interior panels, characterized in that, the composite fiber material is prepared by using the preparation method of the composite fiber material for automotive interior panels according to any one of claims 1-9.

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