Automobile interior roof and method for producing the same

Abstract

The application relates to an automobile interior roof and a preparation method thereof, and relates to the technical field of automobile roof production.A kind of automobile interior roof, including base material and fabric, the preparation method of base material includes the following steps: the composite fiber web of modified bamboo fiber and modified polypropylene fiber is obtained by electrospinning and air-laid process;The fiber skeleton is obtained by microwave curing treatment to the composite fiber web;The fiber skeleton is placed in the microsphere suspension of expanded microspheres, after being completely immersed for a period of time, pass through the infrared heating zone at a certain speed, and then carry out plasma treatment, to obtain the base material;Wherein the modified bamboo fiber is obtained by hemicellulase modified bamboo fiber, and the modified polypropylene fiber is obtained by maleic anhydride grafted polypropylene fiber.The preparation process of the application does not involve the use of liquid glue, which significantly reduces the odor and weight of the automobile interior roof, and the process environment is cleaner and more hygienic, which is a sustainable green production process.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of automobile roof production, in particular to an automobile interior roof and a preparation method thereof. BACKGROUND

[0002] The automobile roof is a decorative cover installed on the top of the vehicle interior, is an important part integrating decoration and functionality, and can effectively reduce the transmission of external noise into the vehicle interior, block heat from entering the vehicle interior in summer, reduce heat loss in the vehicle interior in winter, and maintain a comfortable temperature in the vehicle interior.

[0003] At present, most of the automobile roofs on the market mainly adopt the PU structure, and the production process relies on liquid glue, which not only easily causes the production environment to be dirty and messy, increases the cleaning difficulty, but also increases the odor of the finished roof material. SUMMARY

[0004] In order to solve the problem that the automobile roof adopting the PU structure produces volatile organic compounds such as formaldehyde and benzene series due to the production process relying on liquid glue, resulting in an odor in the vehicle, the application provides an automobile interior roof and a preparation method thereof.

[0005] In a first aspect, the application provides an automobile interior roof, which adopts the following technical scheme:

[0006] An automobile interior roof comprises a base material and a fabric, and the preparation method of the base material comprises the following steps:

[0007] (1) mixing modified bamboo fibers and modified polypropylene fibers at a mass ratio of 7:3 to obtain mixed fibers, and adding part of the mixed fibers into a mixed solvent of dichloromethane and acetone to obtain a spinning solution;

[0008] (2) depositing the spinning solution in the vertical direction to form a fiber bundle by electrospinning for 5 min, uniformly spreading and depositing the mixed fibers in the horizontal direction by airflow for 3 min, and repeatedly depositing 5 times to obtain a composite fiber web;

[0009] (3) microwave curing the composite fiber web for 30-60 s to obtain a fiber skeleton;

[0010] (4) adding thermal expansion microspheres into water to uniformly disperse to form a microsphere suspension, then slowly placing the fiber skeleton into the microsphere suspension to completely immerse for a period of time to obtain a microsphere-loaded fiber skeleton;

[0011] (5) passing the microsphere-loaded fiber skeleton through an infrared heating zone at a speed of 0.1-0.2 m / min, and then performing plasma treatment to obtain the base material;

[0012] The modified bamboo fiber is obtained by treating bamboo fiber with hemicellulase, and the modified polypropylene fiber is obtained by grafting polypropylene with maleic anhydride.

[0013] By adopting the technical scheme, after the modified bamboo fiber is treated with hemicellulase, the number of surface active groups such as hydroxyl groups increases; the modified polypropylene fiber is grafted with maleic anhydride to introduce polar groups such as carboxyl anhydride, which significantly improves the compatibility between the modified bamboo fiber and the modified polypropylene fiber. Meanwhile, the microwave curing treatment promotes the molecular level combination between fibers by using the thermal effect, and the infrared heating and the plasma treatment further strengthen the bonding force between the fibers and the microspheres and between the fibers, so that the whole process does not need glue, thereby eliminating the VOCs release caused by the glue and greatly reducing the peculiar smell in the vehicle.

[0014] In the composite fiber web of the application, the mixed fiber bundles in the vertical direction provide longitudinal strength support, so that the substrate is not easy to break when subjected to external longitudinal force; the mixed fibers spread in the horizontal direction ensure that the substrate has good toughness and uniformity in the transverse direction, forming a three-dimensional fiber structure intersecting in the longitudinal and transverse directions, which can effectively improve the overall mechanical properties of the substrate.

[0015] The heat-expandable microspheres are attached to the fiber skeleton, and the density of the substrate is controlled by the temperature and time of infrared heating, so that a microcavity structure is formed in the substrate, thereby enhancing the heat and sound insulation performance of the automobile roof; at the same time, the heat-expandable microspheres can also be combined with the mechanical properties of the fiber skeleton to effectively absorb energy and provide a certain buffer when subjected to external force impact.

[0016] The continuous plasma treatment of the fiber surface can generate oxygen-containing polar groups, effectively improve the interfacial shear strength of the modified bamboo fiber and the modified polypropylene fiber, and further improve the mechanical properties of the substrate.

[0017] Preferably, the preparation method of the modified bamboo fiber comprises the following steps:

[0018] S1. Immersing the bamboo fiber in a buffer solution containing hemicellulase, and simultaneously applying ultrasonic waves to obtain enzyme-treated fiber;

[0019] S2. Passing the enzyme-treated fiber through a first temperature zone, a second temperature zone and a third temperature zone in sequence, and stopping at each temperature zone for a period of time to obtain initial modified bamboo fiber;

[0020] S3. Acid washing, water washing and drying the initial modified bamboo fiber in sequence to obtain the modified bamboo fiber;

[0021] The temperature of the first temperature zone is 50℃, the temperature of the second temperature zone is 75℃, and the temperature of the third temperature zone is 110℃.

[0022] By adopting the technical scheme, the ultrasonic wave accelerates the contact and reaction of the enzyme and the bamboo fiber, improves the enzymolysis efficiency, and makes the enzymolysis more sufficient and uniform. The gradient temperature treatment realizes the structure reconstruction of "drying-unwinding-crystallization": the first temperature zone removes free water in the enzymolysis fiber through low-temperature drying, avoids water from causing fiber swelling or thermal damage in high-temperature treatment, the second temperature zone further unwinds the molecular chain entanglement after enzymolysis, and improves the flexibility of the bamboo fiber, and the third temperature zone promotes the rearrangement of the disordered cellulose chains after enzymolysis, and forms a more regular crystal structure.

[0023] Preferably, the power of the ultrasonic wave in S1 is 120-150w.

[0024] By adopting the technical scheme, when the power of the ultrasonic wave is too low, the enzymolysis efficiency is relatively low, and there is hemicellulose residue; when the power of the ultrasonic wave is too high, the bamboo fiber may be excessively damaged, and the performance of the modified bamboo fiber is reduced; therefore, the applicant finally determines that the power of the ultrasonic wave in the application is above the above range.

[0025] Preferably, the time for the enzymolysis fiber to stay in each temperature zone in S2 is 8-12min.

[0026] By adopting the technical scheme, the above residence time range can ensure that the drying, unwinding, crystallization and other physical and chemical changes in each temperature zone are fully carried out, and at the same time, the performance of the bamboo fiber is prevented from being deteriorated due to excessive treatment; the total treatment time of the three temperature zones meets the thermodynamic requirements of the fiber structure reconstruction, and at the same time, the production line efficiency is prevented from being reduced due to too long time.

[0027] Preferably, when the enzymolysis fiber stays in the third temperature zone in S2, nano-silica aerogel is sprayed to the enzymolysis fiber, and after staying in the third temperature zone for a period of time, the initial modified bamboo fiber is obtained.

[0028] By adopting the technical scheme, under the third temperature zone, the cellulose chains of the bamboo fiber are in a dynamic rearrangement process, the nano-silica aerogel particles can act as "crystallization induction points", promote the ordered arrangement of the cellulose molecular chains, improve the crystallinity, and thus enhance the axial tensile strength and rigidity of the bamboo fiber.

[0029] At the same time, the silicon hydroxyl groups on the surface of the nano-silica aerogel can form hydrogen bonds with the hydroxyl groups on the surface of the bamboo fiber, and part of the silicon hydroxyl groups may also dehydrate and condense to form -Si-O-C- covalent bonds under high temperature, which significantly enhances the interfacial bonding between the aerogel and the bamboo fiber.

[0030] The nano-silica aerogel is also an excellent thermal insulation material, and its nanopores can hinder heat conduction; at the same time, its porous structure has scattering and absorption effects on sound waves, and can cooperate with the cavity structure of the thermal expansion microspheres to improve the thermal insulation and sound insulation performance of the base material.

[0031] Preferably, the heat-expandable microspheres are one of methyl methacrylate copolymer microspheres and core-shell structured hydrocarbon microspheres.

[0032] By adopting the above technical solution, the methyl methacrylate copolymer microspheres and the core-shell structured hydrocarbon microspheres both have good thermal expansion performance, and the thermal expansion temperature ranges of the two are adapted to the heating conditions in the process of preparing the base material, so that they can expand at a suitable temperature to form a stable cavity structure.

[0033] Preferably, the heat-expandable microspheres are methyl methacrylate copolymer microspheres.

[0034] Preferably, the initial particle size of the methyl methacrylate copolymer microspheres is 20-40 μm.

[0035] By adopting the above technical solution, the methyl methacrylate copolymer microspheres are designed by copolymerization of methyl methacrylate and other monomers to form a dense cross-linked structure, which can effectively resist hydrolysis and degradation in a high-temperature and high-humidity environment, and the hydrophobic polymer segment can reduce water penetration, thereby maintaining stable physical properties and having excellent moisture and heat resistance to continuously maintain the cavity structure for heat and sound insulation.

[0036] Meanwhile, the shell layer of the methyl methacrylate copolymer microspheres contains ester groups, and the nano-silica aerogel added in the modified bamboo fiber is rich in silicon hydroxyl groups, and hydrogen bond interaction can be formed between the two, further enhancing the overall compatibility of the three-dimensional fiber network and the microspheres.

[0037] The methyl methacrylate copolymer microspheres with an initial particle size of 20-40 μm are matched with the pore size of the composite fiber web, which can form a large enough cavity to hinder heat conduction and sound wave propagation, and will not cause deformation of the fiber skeleton due to excessive expansion.

[0038] Preferably, the preparation method of the modified polypropylene fiber comprises the following steps: blending polypropylene particles with maleic anhydride and an initiator, melt grafting at 180-200°C, and obtaining the modified polypropylene fiber after traction cooling.

[0039] By adopting the above technical solution, the modified polypropylene fiber obtained by grafting maleic anhydride on polypropylene fiber can effectively improve the compatibility between the modified polypropylene fiber and the modified bamboo fiber, thereby significantly improving the structural stability of the three-dimensional fiber structure.

[0040] In a second aspect, the application provides a preparation method of the automobile interior ceiling.

[0041] The preparation method of the automobile interior ceiling is used for preparing the automobile interior ceiling described above, and comprises the following steps.

[0042] 1) The substrate is heated to a surface temperature of 160-170°C, the sunroof reinforcing frame is placed into the corresponding pit of the lower mold by a mechanical hand, the fabric is automatically transmitted to the middle position of the upper and lower molds, the substrate is automatically transmitted to the middle position of the upper and lower molds and located below the fabric, the upper mold is automatically lowered, and the pressure forming is obtained to obtain a ceiling initial type;

[0043] 2) The ceiling initial type is placed into a punching die, and is positioned by the shape of the sunroof opening. The pressure holding pressure of the punching press is 200-220 bar, the pressure holding time is 5-7 s, the punching die has a floating pressure plate and a cold mold cold knife, and the excess edge hole is punched off by the cold mold cold knife to obtain a ceiling base type;

[0044] 3) The sunroof opening substrate and the fabric of the ceiling base type are integrally rolled and covered to obtain the automobile interior ceiling.

[0045] In summary, the present application has the following beneficial effects:

[0046] 1) The present application provides longitudinal strength support by vertically mixed fiber bundles, and forms a uniform toughness structure by horizontally mixed fibers (modified bamboo fibers and modified polypropylene fibers), constructs a three-dimensional fiber skeleton intersecting longitudinally and transversely, significantly improves the anti-fracture ability and overall structural stability of the substrate, and meets the mechanical strength requirements of automobile interiors;

[0047] 2) The present application forms a microcavity structure after infrared heating by the thermal expansion microspheres, and combines the porous properties of nano-silica aerogel to synergistically hinder heat conduction and sound wave propagation, effectively improving the sound insulation and heat insulation performance of the automobile interior ceiling;

[0048] 3) The present application realizes the reconstruction of the crystalline structure by gradient temperature treatment of the modified bamboo fibers, and enhances the rigidity of the substrate by taking nano-silica aerogel as a crystallization induction point; and the particle size of the thermal expansion microspheres is matched with the fiber pore space to maintain the long-term stability of the cavity structure;

[0049] 4) The preparation process of the present application does not involve the use of liquid glue, which significantly reduces the odor and weight of the automobile interior ceiling, and the process environment is cleaner and more sanitary, which is a sustainable green production process. DETAILED DESCRIPTION

[0050] The raw materials (except for special instructions, all are commercially available products) in the present application include the following parts:

[0051] Hemicellulase: enzyme activity is 1 U / mg;

[0052] Bamboo fiber: diameter is 15±3 mm, linear density is 25±3 tex;

[0053] Polypropylene particles: commercially available product with CAS number 9003-07-0;

[0054] Maleic anhydride: commercially available product with CAS number 108-31-6;

[0055] Nano-silica aerogel: hydrophobic type;

[0056] Methyl methacrylate copolymer microspheres: Matsumoto Japan F-30D (initial particle size 10-18 μm), F-230D (initial particle size 20-35 μm);

[0057] Core-shell structured hydrocarbon microspheres: Kureha Microsphere®;

[0058] Initiator: commercially available product using dicumyl peroxide.

[0059] Modified bamboo fiber:

[0060] Preparation Example 1

[0061] The preparation method of the modified bamboo fiber comprises the following steps:

[0062] S1. Dissolve hemicellulase in water, adjust the pH of the solution to 5.5 to obtain a hemicellulase-containing buffer; immerse the bamboo fiber in the hemicellulase-containing buffer, and simultaneously apply 40 kHz ultrasonic waves (power 130 W, pulse mode) to obtain an enzymatic fiber;

[0063] S2. Place the enzymatic fiber on a moving conveyor belt to sequentially pass through a first temperature zone (50°C), a second temperature zone (75°C), and a third temperature zone (110°C), and stay for 10 min in each temperature zone to obtain an initial modified bamboo fiber;

[0064] S3. Subject the initial modified bamboo fiber to acid washing (5 wt% oxalic acid solution), water washing, and drying (60°C) in sequence to obtain the modified bamboo fiber.

[0065] Preparation Example 2

[0066] The preparation method of the modified bamboo fiber differs from that of Preparation Example 1 in that the power of the ultrasonic waves in S1 is 100 W.

[0067] Preparation Example 3

[0068] The preparation method of the modified bamboo fiber differs from that of Preparation Example 1 in that the power of the ultrasonic waves in S1 is 120 W.

[0069] Preparation Example 4

[0070] The preparation method of the modified bamboo fiber differs from that of Preparation Example 1 in that the power of the ultrasonic waves in S1 is 150 W.

[0071] Preparation Example 5

[0072] The preparation method of the modified bamboo fiber differs from that of Preparation Example 1 in that the power of the ultrasonic wave in S1 is 180 W.

[0073] Preparation Example 6

[0074] The preparation method of the modified bamboo fiber differs from that of Preparation Example 1 in that the enzymatic fibers in S2 stay for 5 min in each temperature zone.

[0075] Preparation Example 7

[0076] The preparation method of the modified bamboo fiber differs from that of Preparation Example 1 in that the enzymatic fibers in S2 stay for 8 min in each temperature zone.

[0077] Preparation Example 8

[0078] The preparation method of the modified bamboo fiber differs from that of Preparation Example 1 in that the enzymatic fibers in S2 stay for 12 min in each temperature zone.

[0079] Preparation Example 9

[0080] The preparation method of the modified bamboo fiber differs from that of Preparation Example 1 in that the enzymatic fibers in S2 stay for 15 min in each temperature zone.

[0081] Preparation Example 10

[0082] The preparation method of the modified bamboo fiber differs from that of Preparation Example 1 in that the enzymatic fibers in S2 are placed on a moving conveyor belt to sequentially pass through a first temperature zone (50°C) and a second temperature zone (75°C) and stay for 10 min in each temperature zone; when the enzymatic fibers enter a third temperature zone, nano-silica aerogel is sprayed on the enzymatic fibers, and after staying for 10 min in the third temperature zone, the initial modified bamboo fiber is obtained.

[0083] Modified polypropylene fiber:

[0084] Preparation Example 11

[0085] The preparation method of the modified polypropylene fiber comprises the following steps:

[0086] The polypropylene fiber is blended with maleic anhydride, dicumyl peroxide at a mass ratio of 10:2.5:0.35, placed in a screw extruder for melt grafting at 200°C (180-200°C can be used) for 20 min, and then cooled by traction to obtain the modified polypropylene fiber.

[0087] Substrate:

[0088] Preparation Example 12

[0089] The preparation method of the substrate comprises the following steps:

[0090] (1) The modified bamboo fibers obtained in Preparation Example 1 and the modified polypropylene fibers obtained in Preparation Example 11 are mixed in a mass ratio of 7:3 to obtain mixed fibers, and part of the mixed fibers is added to a mixed solvent of dichloromethane and acetone (mass ratio of dichloromethane to acetone is 7:3) to obtain a spinning solution;

[0091] (2) The spinning solution is formed into a fiber bundle in the vertical direction by electrospinning (the spinning voltage is set to 25 kV, the receiving distance is 15 cm, and the solution is pushed at a speed of 1.0 mL / h), and after deposition for 5 min, the mixed fibers are laid on a horizontal plane by an air-laying machine and uniformly spread and deposited for 3 min, and then electrospinning is performed again, and the deposition is repeated for 5 times to obtain a composite fiber web;

[0092] (3) The composite fiber web is subjected to microwave curing treatment, the microwave frequency is set to 2.45 GHz, the power is 800 W, and the treatment is performed for 60 s (30-60 s can be used) to obtain a fiber skeleton;

[0093] (4) Methyl methacrylate copolymer microspheres (F-230D) are added to water to form a microsphere suspension, the mass fraction of the methyl methacrylate copolymer microspheres in the microsphere suspension is 10%, and then the fiber skeleton is slowly put into the microsphere suspension and completely immersed for 30 min to obtain a microsphere-loaded fiber skeleton;

[0094] (5) The microsphere-loaded fiber skeleton is passed through an infrared heating zone at a speed of 0.1 m / min (0.1-0.2 m / min can be used), the temperature of the infrared heating zone is 100°C, and then plasma treatment is performed, an atmospheric pressure helium plasma treatment system is used, the power is set to 300 W, the helium flow rate is 10 L / min, and the treatment speed is 0.5 m / min, and the base material is obtained.

[0095] Preparation Example 13

[0096] The preparation method of the base material is different from that of Preparation Example 12 in that the unmodified bamboo fibers and the unmodified polypropylene fibers are mixed in a mass ratio of 7:3 in step (1) to obtain mixed fibers.

[0097] Preparation Example 14

[0098] The preparation method of the base material is different from that of Preparation Example 12 in that step (4) is not performed, and the fiber skeleton is directly passed through an infrared heating zone at a speed of 0.1 m / min.

[0099] Preparation Example 15

[0100] The preparation method of the base material is different from that of Preparation Example 12 in that the microsphere-loaded fiber skeleton is passed through an infrared heating zone at a speed of 0.1 m / min in step (5) to obtain the base material, and plasma treatment is not performed.

[0101] Preparation Example 16

[0102] The method for preparing the substrate was different from that of Preparation Example 12 in that the modified bamboo fibers obtained in Preparation Example 2 and the modified polypropylene fibers obtained in Preparation Example 11 were mixed in a mass ratio of 7:3 to obtain mixed fibers in step (1).

[0103] Preparation Example 17

[0104] The method for preparing the substrate was different from that of Preparation Example 12 in that the modified bamboo fibers obtained in Preparation Example 3 and the modified polypropylene fibers obtained in Preparation Example 11 were mixed in a mass ratio of 7:3 to obtain mixed fibers in step (1).

[0105] Preparation Example 18

[0106] The method for preparing the substrate was different from that of Preparation Example 12 in that the modified bamboo fibers obtained in Preparation Example 4 and the modified polypropylene fibers obtained in Preparation Example 11 were mixed in a mass ratio of 7:3 to obtain mixed fibers in step (1).

[0107] Preparation Example 19

[0108] The method for preparing the substrate was different from that of Preparation Example 12 in that the modified bamboo fibers obtained in Preparation Example 5 and the modified polypropylene fibers obtained in Preparation Example 11 were mixed in a mass ratio of 7:3 to obtain mixed fibers in step (1).

[0109] Preparation Example 20

[0110] The method for preparing the substrate was different from that of Preparation Example 12 in that the modified bamboo fibers obtained in Preparation Example 6 and the modified polypropylene fibers obtained in Preparation Example 11 were mixed in a mass ratio of 7:3 to obtain mixed fibers in step (1).

[0111] Preparation Example 21

[0112] The method for preparing the substrate was different from that of Preparation Example 12 in that the modified bamboo fibers obtained in Preparation Example 7 and the modified polypropylene fibers obtained in Preparation Example 11 were mixed in a mass ratio of 7:3 to obtain mixed fibers in step (1).

[0113] Preparation Example 22

[0114] The method for preparing the substrate was different from that of Preparation Example 12 in that the modified bamboo fibers obtained in Preparation Example 8 and the modified polypropylene fibers obtained in Preparation Example 11 were mixed in a mass ratio of 7:3 to obtain mixed fibers in step (1).

[0115] Preparation Example 23

[0116] The preparation method of the substrate is different from that of Preparation Example 12 in that the modified bamboo fibers obtained in Preparation Example 9 and the modified polypropylene fibers obtained in Preparation Example 11 are mixed in a mass ratio of 7:3 in step (1) to obtain mixed fibers.

[0117] Preparation Example 24

[0118] The preparation method of the substrate is different from that of Preparation Example 12 in that the modified bamboo fibers obtained in Preparation Example 10 and the modified polypropylene fibers obtained in Preparation Example 11 are mixed in a mass ratio of 7:3 in step (1) to obtain mixed fibers.

[0119] Preparation Example 25

[0120] The preparation method of the substrate is different from that of Preparation Example 12 in that the core-shell structured carbon hydrocarbon microspheres are added to water to form a microsphere suspension, the mass fraction of the methyl methacrylate copolymer microspheres in the microsphere suspension is 10%, and then the fiber skeleton is slowly placed in the microsphere suspension to be completely immersed for 30 min to obtain a microsphere-loaded fiber skeleton.

[0121] Preparation Example 26

[0122] The preparation method of the substrate is different from that of Preparation Example 12 in that the methyl methacrylate copolymer microspheres (F-30D) are added to water to form a microsphere suspension, the mass fraction of the methyl methacrylate copolymer microspheres in the microsphere suspension is 10%, and then the fiber skeleton is slowly placed in the microsphere suspension to be completely immersed for 30 min to obtain a microsphere-loaded fiber skeleton.

[0123] The application will be further described in detail below in combination with examples and comparative examples.

[0124] Example 1

[0125] A preparation method of an automotive interior roof, comprising the following steps:

[0126] 1) The substrate prepared in Preparation Example 12 is heated to a surface temperature of 170°C (160-170°C can be used), the sunroof reinforcing frame is placed in the corresponding pit of the lower mold by the X direction mechanical hand, the fabric is automatically transmitted into the middle position of the upper and lower molds by the Y direction, the heated substrate is automatically transmitted into the middle position of the upper and lower molds by the -Y direction and is located below the fabric, the upper mold is automatically lowered, and the roof is formed under a molding pressure of 20°C and 40 bar for 33 s to obtain a roof prototype;

[0127] 2) Put the ceiling initial model into the punching die, and position it by the shape of the sunroof window. The holding pressure of the punching press is 210 bar (200-220 bar is also acceptable), the holding time is 7 s (5-7 s is also acceptable), the punching die has a floating pressure plate and a cold mold cold knife. After the cold mold cold knife punches off the excess edge hole, the ceiling base model is obtained;

[0128] 3) The sunroof window base material and the fabric of the ceiling base model are integrally hemmed and covered, and the automotive interior ceiling is obtained.

[0129] Comparative Examples 1-3

[0130] Comparative Example 1 is based on the preparation method of Example 1, and the base material prepared in Preparation Example 12 is replaced with the base material prepared in Preparation Example 13, and the other conditions remain unchanged.

[0131] Comparative Example 2 is based on the preparation method of Example 1, and the base material prepared in Preparation Example 12 is replaced with the base material prepared in Preparation Example 14, and the other conditions remain unchanged.

[0132] Comparative Example 3 is based on the preparation method of Example 1, and the base material prepared in Preparation Example 12 is replaced with the base material prepared in Preparation Example 15, and the other conditions remain unchanged.

[0133] Table 1 Performance test table of Example 1 and Comparative Examples 1-3

[0134]

[0135] The automotive interior ceiling of Example 1 and Comparative Examples 1-3 was subjected to the following performance tests, and the test results are shown in Table 1:

[0136] Performance test

[0137] (1) Odor test

[0138] According to the standards and regulations of PV3900, the odor grade of the automotive interior ceiling was detected.

[0139] (2) Mechanical properties

[0140] An electronic universal testing machine was used to detect the bending strength of the interior ceiling according to SMTC 5330 007-2019, and the data was recorded.

[0141] (3) Sound insulation performance

[0142] Using the sound pressure level method, the sound insulation performance of the ceiling was tested. Sound pressure level test instruments were placed on both sides of the automotive interior ceiling. Sound signals were generated on the source side, transmitted through the ceiling to the receiving side, and the sound pressure levels on both sides were recorded. The sound pressure level difference was calculated to obtain the sound absorption coefficient.

[0143] As can be seen from Table 1, the odor of Example 1 and Comparative Examples 1-3 is less, which is due to the fact that the present application uses microwave curing treatment to promote the molecular level combination between fibers, and the infrared heating and plasma treatment further strengthen the bonding force between the fibers and the microspheres, between the fibers and the fibers, and the whole process does not need glue, which greatly reduces the odor in the vehicle.

[0144] The mechanical properties of the automobile interior ceiling of Example 1 are better than those of Comparative Example 1, which is due to the fact that the bamboo fibers and polypropylene fibers in Comparative Example 1 are not modified, and the compatibility between the modified bamboo fibers and the modified polypropylene fibers in Example 1 is better, and the structure is more stable.

[0145] The sound insulation performance of the automobile interior ceiling of Example 1 is better than that of Comparative Example 2, which is due to the fact that the fiber skeleton in Comparative Example 2 is not loaded with methyl methacrylate copolymer microspheres, and the methyl methacrylate copolymer microspheres in Example 1 are attached to the fiber skeleton, and through infrared heating, a small cavity structure is formed inside the substrate, which can significantly improve the sound insulation performance of the substrate.

[0146] The mechanical properties of the automobile interior ceiling of Example 1 are better than those of Comparative Example 3, which is due to the fact that Comparative Example 3 is not subjected to plasma treatment, and the plasma continuous treatment of the fiber surface in Example 1 can generate oxygen-containing polar groups, effectively improving the interfacial shear strength of the modified bamboo fibers and the modified polypropylene fibers, and improving the mechanical properties of the substrate.

[0147] Examples 2-5

[0148] Example 2 is prepared on the basis of the preparation method of Example 1, the substrate prepared in Preparation Example 12 is replaced with the substrate prepared in Preparation Example 16, and the other conditions remain unchanged.

[0149] Example 3 is prepared on the basis of the preparation method of Example 1, the substrate prepared in Preparation Example 12 is replaced with the substrate prepared in Preparation Example 17, and the other conditions remain unchanged.

[0150] Example 4 is prepared on the basis of the preparation method of Example 1, the substrate prepared in Preparation Example 12 is replaced with the substrate prepared in Preparation Example 18, and the other conditions remain unchanged.

[0151] Example 5 is prepared on the basis of the preparation method of Example 1, the substrate prepared in Preparation Example 12 is replaced with the substrate prepared in Preparation Example 19, and the other conditions remain unchanged.

[0152] The automobile interior ceiling of Examples 2-5 is subjected to the above performance detection, and the detection results are shown in Table 2.

[0153] Table 2 Performance detection table of Examples 1-5

[0154]

[0155] As can be seen from Table 2, the power of the ultrasonic waves is too low or too high, which can result in the decrease of the mechanical properties of the automobile interior roof, because when the power of the ultrasonic waves is too low, the enzymatic hydrolysis efficiency is relatively low, and there is residual hemicellulose, which can be partially degraded (such as glycosidic bond breakage) due to insufficient heat resistance in the subsequent processing process, resulting in the destruction of the structural integrity of the fiber skeleton; when the power of the ultrasonic waves is too high, the bamboo fibers can be excessively damaged, resulting in the decrease of the comprehensive performance of the modified bamboo fibers.

[0156] Example 6-9

[0157] Example 6 is based on the preparation method of Example 1, the substrate prepared in Preparation Example 12 is replaced with the substrate prepared in Preparation Example 20, and the other conditions remain unchanged.

[0158] Example 7 is based on the preparation method of Example 1, the substrate prepared in Preparation Example 12 is replaced with the substrate prepared in Preparation Example 21, and the other conditions remain unchanged.

[0159] Example 8 is based on the preparation method of Example 1, the substrate prepared in Preparation Example 12 is replaced with the substrate prepared in Preparation Example 22, and the other conditions remain unchanged.

[0160] Example 9 is based on the preparation method of Example 1, the substrate prepared in Preparation Example 12 is replaced with the substrate prepared in Preparation Example 23, and the other conditions remain unchanged.

[0161] The automobile interior roof of Examples 6-9 is subjected to the above performance detection, and the detection results are shown in Table 3.

[0162] Table 3 Performance detection table of Example 1 and Examples 6-9

[0163]

[0164] As can be seen from Table 3, the residence time of the enzymatic hydrolysis fibers in each temperature zone is too short or too long, which can result in the decrease of the mechanical properties of the automobile interior roof, because the residence time is too short, which can result in insufficient physical and chemical changes such as drying, disentangling and crystallization of the enzymatic hydrolysis fibers, and the crystallinity is too low, which can result in the decrease of the supportability of the modified bamboo fibers; the residence time is too long, which can also result in the performance degradation of the bamboo fibers due to excessive processing.

[0165] Example 10

[0166] Example 10 is based on the preparation method of Example 1, the substrate prepared in Preparation Example 12 is replaced with the substrate prepared in Preparation Example 24, and the other conditions remain unchanged.

[0167] The automobile interior roof of Example 10 was subjected to the performance test as above, and the test results are shown in Table 4.

[0168] Table 4 Performance test table of Example 1 and Example 10

[0169]

[0170] As shown in Table 4, it can be seen from the comparison between Comparative Example 1 and Example 10 that the mechanical properties and sound insulation performance of the automobile interior roof of Example 10 are superior to those of Example 1, which is because under the third temperature zone, the nano-silica aerogel particles can act as "crystallization induction points" to improve the crystallinity of the modified bamboo fibers and enhance the mechanical properties of the bamboo fibers.

[0171] Meanwhile, the nanopores of the nano-silica aerogel have scattering and absorption effects on sound waves, which can synergistically improve the sound insulation performance of the substrate together with the cavity structure of the methyl methacrylate copolymer microspheres.

[0172] Example 11

[0173] Example 11 is based on the preparation method of Example 1, and the substrate prepared in Preparation Example 12 is replaced with the substrate prepared in Preparation Example 25, and the other conditions remain unchanged.

[0174] The automobile interior roof of Example 11 was subjected to the performance test as above, and the test results are shown in Table 4.

[0175] Table 5 Performance test table of Example 1 and Example 11

[0176]

[0177] As shown in Table 5, it can be seen from the comparison between Comparative Example 1 and Example 11 that both the methyl methacrylate copolymer microspheres and the core-shell structure hydrocarbon microspheres can effectively maintain the sound insulation performance of the automobile interior roof, which is because the methyl methacrylate copolymer microspheres and the core-shell structure hydrocarbon microspheres both have good thermal expansion properties, and the thermal expansion temperature ranges of the two are suitable for the heating conditions in the substrate preparation process, and they can expand at appropriate temperatures to form stable cavity structures.

[0178] The sound insulation performance of the automobile interior roof of Example 1 is superior to that of Example 11, so the methyl methacrylate copolymer microspheres are preferred.

[0179] Example 12

[0180] Example 12 is based on Example 1, and the substrate prepared in Preparation Example 12 is replaced with the substrate prepared in Preparation Example 26, and the other conditions remain unchanged.

[0181] The automobile interior roof of Example 12 was subjected to the performance test as above, and the test results are shown in Table 4.

[0182] Table 6 Performance test table of Example 1 and Example 12

[0183]

[0184] As shown in Table 6, it can be seen from Comparative Example 1 and Example 12 that the initial particle size of the methyl methacrylate copolymer microspheres is too small to cause the sound insulation performance of the automobile interior roof to decrease, because the initial particle size is too small to form a large enough cavity to hinder the propagation of sound waves.

[0185] The specific embodiments are only an explanation of the present application, which is not a limitation to the present application. Those skilled in the art can make modifications to the present embodiments without creative contribution after reading the present specification, but as long as the present application is within the scope of the claims, it is protected by the patent law.

Claims

1. An automotive interior headliner comprising a substrate and a facing, characterized in that, The preparation method of the substrate comprises the following steps: (1) mixing modified bamboo fibers and modified polypropylene fibers according to a mass ratio of 7:3 to obtain mixed fibers, and adding part of the mixed fibers into a mixed solvent of dichloromethane and acetone to obtain a spinning solution; (2) depositing the spinning solution in a vertical direction to form a fiber bundle for 5 min through electrospinning, and then uniformly spreading and depositing the mixed fibers in a horizontal direction through airflow for 3 min, and repeating the deposition for 5 times to obtain a composite fiber web; (3) performing microwave curing treatment on the composite fiber web for 30-60 s to obtain a fiber skeleton; (4) adding the heat-expandable microspheres into water to uniformly disperse to form a microsphere suspension, and then slowly placing the fiber skeleton into the microsphere suspension to be completely immersed for a period of time to obtain a microsphere-loaded fiber skeleton; (5) passing the microsphere-loaded fiber skeleton through an infrared heating zone at a speed of 0.1-0.2 m / min, and then performing plasma treatment to obtain the substrate; The modified bamboo fibers are obtained from hemicellulase-modified bamboo fibers, and the preparation method comprises the following steps: S1. immersing the bamboo fibers in a buffer solution containing hemicellulase, and synchronously applying ultrasonic waves to obtain enzyme-treated fibers; S2. sequentially passing the enzyme-treated fibers through a first temperature zone, a second temperature zone and a third temperature zone, and stopping at each temperature zone for 8-12 min to obtain initial modified bamboo fibers; S3. sequentially performing acid washing, water washing and drying on the initial modified bamboo fibers to obtain modified bamboo fibers; The temperature of the first temperature zone is 50℃, the temperature of the second temperature zone is 75℃, and the temperature of the third temperature zone is 110℃; In S2, when the enzyme-treated fibers stop at the third temperature zone, nano-silica aerogel is sprayed on the enzyme-treated fibers, and after stopping at the third temperature zone for 10 min, the initial modified bamboo fibers are obtained; The modified polypropylene fibers are obtained from maleic anhydride grafted polypropylene fibers, and the preparation method comprises the following steps: blending polypropylene particles with maleic anhydride and an initiator, melt grafting at 180-200℃, and then obtaining modified polypropylene fibers after traction cooling.

2. The automotive interior headliner of claim 1, wherein: The power of the ultrasonic waves in S1 is 120-150 W.

3. The automotive interior headliner of claim 1, wherein: The heat-expandable microspheres are one of methyl methacrylate copolymer microspheres and core-shell structure hydrocarbon microspheres.

4. The automotive interior headliner of claim 3, wherein: The heat-expandable microspheres are methyl methacrylate copolymer microspheres.

5. The automotive interior headliner of claim 4, wherein: The initial particle size of the methyl methacrylate copolymer microspheres is 20-40 μm.

6. The method of producing an automotive interior headliner according to any one of claims 1 to 5, characterized in that, Comprise the following steps: 1) heating the substrate to a surface temperature of 160-170℃, placing the sunroof reinforcing frame into the corresponding recesses of the lower mold by a mechanical hand, automatically transferring the fabric into the middle position of the upper and lower molds, automatically transferring the substrate into the middle position of the upper and lower molds and below the fabric, automatically lowering the upper mold, and performing pressure forming to obtain a ceiling initial type; 2) placing the ceiling initial type into a punching die, positioning by the shape of the sunroof opening, the pressure holding pressure of the punching press is 200-220 bar, the pressure holding time is 5-7 s, the punching die is provided with a floating pressure plate and a cold mold cold knife, and after punching off the excess edge hole by the cold mold cold knife, a ceiling base type is obtained; 3) integrally edge covering the sunroof opening substrate and the fabric of the ceiling base type, and the automobile interior ceiling is obtained.

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