Mildew-proof and antistatic automobile trunk inner lining plate material and preparation method thereof

Abstract

The invention relates to the field of materials, and particularly discloses a mildew-proof and antistatic automobile trunk inner lining plate material and a preparation method thereof.The mildew-proof and antistatic automobile trunk inner lining plate material is prepared by adopting flax fibers, zirconia ceramic fibers and carbon fibers to be compounded to serve as a reinforcing framework, conducting vacuum drying and activation on the reinforcing framework, pretreating graphene oxide and dispersing the graphene oxide in a fiber network; according to the present invention, the mold inhibitor and the antibacterial agent are added to form the uniform and lasting release source of the mold inhibitor and the antibacterial agent, and the composite binder and the composite auxiliary agent are adopted, and the graded pressurization cold pressing molding process is adopted so as to compact the fiber network, effectively release the internal stress, and avoid the structural damage caused by the single high pressure so as to obtain the low-porosity and high-strength compact structure; the inner supporting plate material has efficient and broad-spectrum antibacterial performance and rapid and lasting static dissipation capacity, achieves the best balance among mechanical strength, durability, mildew-proof and antistatic performance and environmental protection performance, meets the application requirements of inner lining plates of automobile trunks, and has high practical application value.

Description

Technical Field

[0001] This invention belongs to the technical field of automotive materials, specifically relating to a mildew-proof and antistatic automotive trunk lining material and its preparation method. Background Technology

[0002] The hard plastic part inside the trunk lid of a car is the lining panel. The lining panel has impact resistance and, together with the inside of the trunk lid, provides impact protection and support. As a relatively enclosed space, the trunk is used to store various items daily, and some car trunks used for transportation are frequently exposed to various goods. After storing items with high humidity or in humid climates, it is prone to mold and bacteria growth, which is troublesome to clean and harmful to human health. In dry environments, many lining panel materials are prone to static electricity and dust accumulation, attracting dust and bacteria, which is unsightly and affects the environment of the trunk. Therefore, promoting trunk lining panels with antibacterial, anti-mold, and anti-static properties can meet more needs.

[0003] Currently, trunk lining panels are made of various materials, including plastics, fiberglass composites, aluminum alloys, high-strength fiberboard, and PP wood powder boards. Among them, high-strength fiberboard is low in manufacturing cost, has excellent physical properties, is lightweight, high in strength, and uniform in quality, combining cost-effectiveness and performance. However, it has a certain odor problem. This is because the raw materials added during the manufacturing process include various chemical additives, such as adhesives, and preservatives are added to extend the service life and shelf life of the panels. Furthermore, the production process requires high temperature and high pressure molding, which can easily release irritating gases such as acetaldehyde. The resulting panels also have weak anti-mildew, antibacterial, and antistatic properties. Therefore, a lining panel that can overcome the above problems is needed to meet higher market demands. Summary of the Invention

[0004] To address the above problems, the present invention aims to provide a mildew-proof and antistatic automotive trunk lining material and its preparation method.

[0005] The technical content of this invention is as follows: This invention provides a mildew-proof and antistatic car trunk lining material, comprising the following components by weight: 2-3 parts of pretreated graphene oxide, 20-30 parts of bast fiber, 35-40 parts of zirconia ceramic fiber, 8-16 parts of carbon fiber, 8-11 parts of composite binder, 6-9 parts of stearic acid, and 3-5 parts of composite additives. The preparation of the pretreated graphene oxide includes: immersing graphene oxide in a phosphate solution containing 20-30 wt% calcium propionate at a solid-liquid ratio of (2-4):(11-15) g / mL, with a pH of 5.5-7.0; adding 10-20 wt% (of the total solution) cerium nitrate for dispersion and drying; the graphene oxide can be surface modified with phosphate to optimize its dispersibility and hygroscopicity; the calcium propionate introduces Ca... 2+ It can enhance antistatic properties and compatibility with fiber composites, and assist in antibacterial activity; and utilizes Ce in cerium nitrate. 3+ It can coordinate with oxygen-containing groups in graphene oxide to enhance antibacterial properties, improve dispersibility, and also resist oxidation to extend the functional life. The two can synergistically improve the antifungal and antistatic properties of graphene oxide.

[0006] The preparation of the composite adhesive includes the following steps: 1) Hydrogenated castor oil emulsification: Hydrogenated castor oil is melted at 90-95℃, and an equal amount of alkyl glycoside and deionized water are added. The mixture is then subjected to high-speed shearing (3000-4000 rpm, 3-5 min) to form an emulsion. After cooling to room temperature, the emulsified hydrogenated castor oil is uniformly dispersed in the system, which helps improve the coatability of the binder. As a bio-based toughening agent and hydrophobic agent, its long-chain fatty acid structure acts like "rubber particles" in the material, improving its impact toughness. Simultaneously, its hydrophobic properties help reduce the water absorption rate of the material. 2) Preparation of composite colloid: Acetylated lignin, hydroxypropyl methylcellulose and sodium carboxymethylcellulose are mixed in a mass ratio of (3-4):(10-12):(2-3), and added to deionized water at a material-to-liquid ratio of 1:(2~3) mg / mL. The mixture is stirred at 60-70℃ for 30 min until completely dissolved to form a homogeneous colloid. The acetylated lignin is prepared by mixing lignin and acetic anhydride at a mass ratio of (10~15):(3~5), heating to 60~70℃ and stirring to carry out acetylation, reducing polarity and introducing ester groups, and then pulverizing after vacuum drying for later use. Lignin is rich in phenolic hydroxyl and alcoholic hydroxyl groups. The acetylation reaction replaces some of its hydroxyl groups and introduces ester groups with greater steric hindrance and weaker polarity, which greatly reduces the polarity of lignin and makes it more compatible with organic components such as hydroxypropyl methylcellulose and hydrogenated castor oil. 3) Preparation of composite binder: Keep the temperature at 70~80℃, increase the speed to 2500-3000 rpm and stir at high speed for 4-6 minutes. Through high-speed shearing, the colloidal agglomeration is destroyed, and mechanical force and heat energy are used to promote the physical entanglement and hydrogen bonding of acetylated lignin and cellulose molecular chains, thereby forming a more uniform and stable colloidal network structure. Then slowly add 6-10 wt% (of total mass) of hydrogenated castor oil emulsion, and stir at 1000-2000 rpm for 1-3 minutes to form a uniform and stable composite binder system. Cool to below 40°C and discharge.

[0007] In the preparation of the composite adhesive, hydroxypropyl methylcellulose, sodium carboxymethyl cellulose, etc. contain a large number of hydroxyl groups and ether bonds, which can adsorb trace amounts of moisture in the environment and form a thin water film, which helps to dissipate static charge. In addition, alkyl glycosides, as a natural nonionic surfactant, have certain antibacterial properties and work synergistically with the phenolic hydroxyl groups of lignin to enhance the adhesive's antifungal and antibacterial capabilities.

[0008] The composite additive comprises polylactic acid glycol and hydroxyethyl cashew nut shell oil ether in a mass ratio of 20-30:5-10. Polylactic acid glycol, as a bio-based raw material, has good environmental protection and compatibility, and can enhance the interfacial bonding force with other components (such as fibers and binders), thereby improving the overall mechanical stability of the material. The long-chain hydrophobic structure of hydroxyethyl cashew nut shell oil ether can give the material certain waterproof and stain-resistant properties, reduce liquid penetration and stain adhesion, and facilitate interior cleaning and maintenance. It also has certain weather resistance and antibacterial properties.

[0009] This invention also provides a method for preparing a mildew-resistant and antistatic automotive trunk lining material, comprising the following steps: Step 1: Vacuum dry and activate the bast fiber, zirconia ceramic fiber and carbon fiber respectively to ensure that the moisture content is ≤3% to avoid moisture affecting the bonding effect; The carbon fiber can be pre-soaked in a 5% nitric acid solution at room temperature for 30 minutes to introduce carboxyl groups to enhance compatibility with the binder, and then washed with deionized water until neutral and dried. The pretreated graphene oxide was mixed with the above three types of fibers and stirred at high speed until homogeneous. Step 2: Heat the composite adhesive to 50~60℃, add stearic acid and composite additives and mix well. Spray evenly into the mixture in Step 1), stirring while spraying to ensure that the fiber surface is evenly coated with the mixed solution. After completion, cold press molding is performed to obtain the composite fiber blank. The cold pressing temperature is 5~10℃, the pressure is 8~10MPa, and the time is 30s~1min; Step 3: Next, press the composite fiber blank into a mold. Use a press machine to hold the pressure at 6-10MPa for 10-15s, then hold the pressure at 3-4MPa for 20-30s for graded pressurization. Finally, release the pressure and perform edge trimming and polishing to obtain the inner lining material. After cold pressing, a graded pressurization process is carried out. The initial high pressure can eliminate air bubbles and allow the solvent to fully impregnate the fibers. After the pressure is reduced, there is space between the fibers and the solvent for re-pressing, which can promote the melting and cross-linking of the binder, form a uniform pore structure, improve the air permeability of the inner lining material, prevent moisture absorption and mold growth, and increase the fiber density, thereby improving its antistatic properties.

[0010] The beneficial effects of this invention are as follows: This invention provides a mildew-proof and antistatic automotive trunk lining material. It utilizes a composite of flax fiber, zirconia ceramic fiber, and carbon fiber as a reinforcing skeleton, which is then vacuum-dried and activated. Graphene oxide is pretreated and dispersed within the fiber network, forming a uniform and durable source of release for both the mildew-proofing agent (calcium propionate) and the antibacterial agent (cerium nitrate). Simultaneously, composite binders and additives are used, along with a graded pressure cold-pressing molding process, to compact the fiber network and effectively release internal stress, avoiding structural damage caused by single high pressure. This results in a dense structure with low porosity and high strength. By leveraging the synergistic effects of pretreated graphene oxide (calcium propionate + cerium nitrate), alkyl glycosides, hydroxyethyl cashew nut shell oil ether, and lignin phenolic hydroxyl groups, a highly efficient, broad-spectrum, and long-lasting antifungal and antibacterial effect is achieved. A network conductive system composed of carbon fibers and pretreated graphene oxide is constructed, complementing the hygroscopic and conductive mechanism of the binder to achieve stable and rapid electrostatic dissipation. Hydrogenated castor oil emulsion and hydroxyethyl cashew nut shell oil ether together construct a hydrophobic system. Combined with the dense and breathable structure formed by graded pressurization, the material possesses low water absorption, high wear resistance, and good dimensional stability, resulting in a long service life. The combination of cold pressing and graded pressurization processes solves problems such as fiber wetting, stress release, and pore control, ensuring the uniformity and stability of product performance, making it suitable for mass production. Detailed Implementation

[0011] The present invention will be further described in detail below through specific implementation examples. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of protection of the present invention. After reading the present invention, any modifications of the present invention in various equivalent forms by those skilled in the art fall within the scope of the appended claims.

[0012] Unless otherwise specified, all raw materials and reagents used in this invention are from the conventional market.

[0013] Example 1 A method for preparing a mildew-resistant and antistatic automotive trunk lining material Step 1: Vacuum dry and activate the flax fiber (bast fiber), zirconium oxide ceramic fiber and carbon fiber respectively to ensure that the moisture content is ≤3% to avoid moisture affecting the bonding effect; The carbon fiber is pre-soaked in a 5% nitric acid solution at room temperature for 30 minutes to introduce carboxyl groups to enhance compatibility with the binder, and then washed with deionized water until neutral before drying. Mix 2.5 parts of pretreated graphene oxide with 25 parts of flax fiber, 37.5 parts of zirconium oxide ceramic fiber and 12 parts of carbon fiber, and stir until homogeneous (1500 rpm, 8 min). The preparation of the pretreated graphene oxide includes: immersing graphene oxide in a phosphate solution containing 25wt% calcium propionate at a solid-liquid ratio of 3:13 g / mL, adding 15wt% cerium nitrate for dispersion and drying; Step 2: Heat 9.5 parts of composite binder to 55°C, add 7.5 parts of stearic acid and 4 parts of composite additive (polylactic acid glycol and hydroxyethyl cashew nut shell oil ether mixed in a mass ratio of 25:8), mix well, and spray evenly onto the mixture in Step 1), stirring while spraying to ensure that the fiber surface is evenly coated with binder. After completion, perform cold pressing molding at a temperature of 7°C, a pressure of 9MPa, and a time of 45s to obtain the composite fiber preform. The preparation of the composite adhesive includes the following steps: 1) Emulsification of hydrogenated castor oil: Melt hydrogenated castor oil at 92°C, add an equal amount of alkyl glycoside and deionized water, and shear at high speed (3500 rpm, 4 min) to form an emulsion, then cool to room temperature for later use; 2) Preparation of composite colloid: Acetylated lignin, hydroxypropyl methylcellulose, and sodium carboxymethyl cellulose were added to deionized water at a mass ratio of 3.5:11:2 and a material-to-liquid ratio of 1:2.5 mg / mL. The mixture was stirred at 65°C for 30 min until completely dissolved to form a homogeneous colloid. Then, 2 wt% (based on the total mass of the aforementioned colloid) of aminosilane coupling agent (KH550) was added, and the mixture was heated to 78°C and stirred for another 25 min. The acetylated lignin is prepared by mixing lignin and acetic anhydride at a mass ratio of 12:4, heating to 65°C and stirring to acetylate, reducing polarity and introducing ester groups, and then pulverizing after vacuum drying for later use. 3) Preparation of composite binder: Keep the temperature at 75℃, increase the speed to 2800 rpm and stir at high speed for 5 minutes, then slowly add 8 wt% (total mass) hydrogenated castor oil emulsion, maintain stirring at 1500 rpm for 2 minutes to form a uniform and stable composite binder system, and cool to below 40℃ before discharging; Step 3: Next, press the composite fiber blank into a mold. Use a press machine to hold the pressure at 8MPa for 13s, and then hold the pressure at 3MPa for 25s for graded pressurization. After that, release the pressure and perform edge trimming and polishing to obtain the inner lining material.

[0014] Example 2 A method for preparing a mildew-resistant and antistatic automotive trunk lining material Step 1: Vacuum dry and activate the flax fiber, zirconium oxide ceramic fiber and carbon fiber respectively to ensure that the moisture content is ≤3% to avoid moisture affecting the bonding effect; The carbon fiber can be pre-soaked in a 5% nitric acid solution at room temperature for 30 minutes to introduce carboxyl groups to enhance compatibility with the binder, and then washed with deionized water until neutral and dried. Mix 3 parts of pretreated graphene oxide with 30 parts of flax fiber, 40 parts of zirconium oxide ceramic fiber and 16 parts of carbon fiber, and stir until uniform. The preparation of the pretreated graphene oxide includes: immersing graphene oxide in a phosphate solution containing 20 wt% calcium propionate at a solid-liquid ratio of 2:11 g / mL, adding 10 wt% cerium nitrate for dispersion and drying; Step 2: Heat 11 parts of composite binder to 60°C, add 9 parts of stearic acid and 5 parts of composite additive (polylactic acid glycol and hydroxyethyl cashew nut shell oil ether mixed in a mass ratio of 30:10), mix well, and spray evenly into the mixture in Step 1), stirring while spraying (1500 rpm) to ensure that the fiber surface is evenly coated with binder. After completion, perform cold pressing molding at a temperature of 10°C, a pressure of 10MPa, and a time of 30s to obtain composite fiber preform; The preparation of the composite adhesive includes the following steps: 1) Emulsification of hydrogenated castor oil: Melt hydrogenated castor oil at 95°C, add an equal amount of alkyl glycoside and deionized water, and shear at high speed (4000 rpm, 3 min) to form an emulsion, then cool to room temperature for later use; 2) Preparation of composite colloid: Acetylated lignin, hydroxypropyl methylcellulose, and sodium carboxymethyl cellulose were added to deionized water at a mass ratio of 4:12:3 and a material-to-liquid ratio of 1:3 mg / mL. The mixture was stirred at 70°C for 30 min until completely dissolved to form a homogeneous colloid. Then, 3 wt% (of the total mass of the aforementioned colloid) of aminosilane coupling agent (KH550) was added, and the mixture was heated to 75°C and stirred for another 30 min. The acetylated lignin is prepared by mixing lignin and acetic anhydride at a mass ratio of 15:4, heating to 70°C and stirring to carry out acetylation, reducing polarity and introducing ester groups, and then pulverizing after vacuum drying for later use. 3) Preparation of composite binder: Keep the temperature at 75℃, increase the speed to 3000 rpm and stir at high speed for 4 minutes, then slowly add 10wt% (total mass) hydrogenated castor oil emulsion, maintain stirring at 2000 rpm for 1 minute to form a uniform and stable composite binder system, and cool to below 40℃ before discharging; Step 3: Next, press the composite fiber blank into a mold. Use a press machine to hold the pressure at 6MPa for 15s, then hold the pressure at 3MPa for 30s for graded pressure treatment. Finally, release the pressure and perform edge trimming and polishing to obtain the inner lining material.

[0015] Example 3 A method for preparing a mildew-resistant and antistatic automotive trunk lining material Step 1: Vacuum dry and activate the flax fiber, zirconium oxide ceramic fiber and carbon fiber respectively to ensure that the moisture content is ≤3% to avoid moisture affecting the bonding effect; The carbon fiber can be pre-soaked in a 5% nitric acid solution at room temperature for 30 minutes to introduce carboxyl groups to enhance compatibility with the binder, and then washed with deionized water until neutral and dried. Mix 2 parts of pretreated graphene oxide with 20 parts of flax fiber, 35 parts of zirconium oxide ceramic fiber and 8 parts of carbon fiber, and stir until uniform (1200 rpm, 6 min). The preparation of the pretreated graphene oxide includes: immersing graphene oxide in a phosphate solution containing 30wt% calcium propionate at a solid-liquid ratio of 4:15 g / mL, adding 20wt% cerium nitrate for dispersion and drying; Step 2: Heat 8 parts of composite binder to 50°C, add 6 parts of stearic acid and 3 parts of composite additive (polylactic acid glycol and hydroxyethyl cashew nut shell oil ether mixed in a mass ratio of 20:5), mix well, and spray evenly into the mixture in Step 1), stirring while spraying (1500 rpm) to ensure that the fiber surface is evenly coated with binder. After completion, perform cold pressing at a temperature of 5°C, a pressure of 8MPa, and a time of 1min to obtain the composite fiber preform. The preparation of the composite adhesive includes the following steps: 1) Emulsification of hydrogenated castor oil: Melt hydrogenated castor oil at 90°C, add an equal amount of alkyl glycoside and deionized water, and shear at high speed (3000 rpm, 5 min) to form an emulsion, then cool to room temperature for later use; 2) Preparation of composite colloid: Acetylated lignin, hydroxypropyl methylcellulose, and sodium carboxymethyl cellulose were added to deionized water at a mass ratio of 3:10:2 and a material-to-liquid ratio of 1:2 mg / mL. The mixture was stirred at 60°C for 30 min until completely dissolved to form a homogeneous colloid. Then, 1-3 wt% (accounting for the total mass of the aforementioned colloid) of aminosilane coupling agent (KH550) was added, and the mixture was heated to 80°C and stirred for another 20 min. The acetylated lignin is prepared by mixing lignin and acetic anhydride at a mass ratio of 10:3, heating to 60°C and stirring to carry out acetylation, reducing polarity and introducing ester groups, and then pulverizing after vacuum drying for later use. 3) Preparation of composite binder: Keep the temperature at 80℃, increase the speed to 2500 rpm and stir at high speed for 6 minutes, then slowly add 6 wt% (total mass) hydrogenated castor oil emulsion, maintain stirring at 1000 rpm for 1-3 minutes to form a uniform and stable composite binder system, and cool to below 40℃ before discharging; Step 3: Next, press the composite fiber blank into a mold. Use a press machine to hold the pressure at 10MPa for 10s, and then hold the pressure at 4MPa for 20s for graded pressurization. After that, release the pressure and perform edge trimming and polishing to obtain the inner lining material.

[0016] Example 4 A method for preparing a mildew-resistant and antistatic automotive trunk lining material Step 1: Vacuum dry and activate the flax fiber, zirconium oxide ceramic fiber and carbon fiber respectively to ensure that the moisture content is ≤3% to avoid moisture affecting the bonding effect; The carbon fiber can be pre-soaked in a 5% nitric acid solution at room temperature for 30 minutes to introduce carboxyl groups to enhance compatibility with the binder, and then washed with deionized water until neutral and dried. Mix 2.5 parts of pretreated graphene oxide with 22 parts of flax fiber, 38 parts of zirconium oxide ceramic fiber and 10 parts of carbon fiber, and stir until uniform (1400 rpm, 7 min). The preparation of the pretreated graphene oxide includes: immersing graphene oxide in a phosphate solution containing 25wt% calcium propionate at a solid-liquid ratio of 3:11 g / mL, adding 15wt% cerium nitrate for dispersion and drying; Step 2: Heat 10 parts of composite binder to 58°C, add 8 parts of stearic acid and 4.5 parts of composite additive (polylactic acid glycol and hydroxyethyl cashew nut shell oil ether mixed in a mass ratio of 26:7), mix well, and spray evenly onto the mixture in Step 1), stirring while spraying (1500 rpm) to ensure that the fiber surface is evenly coated with binder. After completion, perform cold pressing molding at a temperature of 8°C, a pressure of 9MPa, and a time of 50s to obtain composite fiber preform; The preparation of the composite adhesive includes the following steps: 1) Emulsification of hydrogenated castor oil: Melt hydrogenated castor oil at 95°C, add an equal amount of alkyl glycoside and deionized water, and shear at high speed (3800 rpm, 4 min) to form an emulsion, then cool to room temperature for later use; 2) Preparation of composite colloid: Acetylated lignin, hydroxypropyl methylcellulose, and sodium carboxymethyl cellulose were added to deionized water at a mass ratio of 4:11:3 and a material-to-liquid ratio of 1:2.5 mg / mL. The mixture was stirred at 68°C for 30 min until completely dissolved to form a homogeneous colloid. Then, 1 wt% (based on the total mass of the aforementioned colloid) of aminosilane coupling agent (KH550) was added, and the mixture was heated to 75°C and stirred for another 28 min. The acetylated lignin is prepared by mixing lignin and acetic anhydride at a mass ratio of 13:4, heating to 65°C and stirring to acetylate, reducing polarity and introducing ester groups, and then pulverizing after vacuum drying for later use. 3) Preparation of composite binder: Keep the temperature at 75℃, increase the speed to 2700 rpm and stir at high speed for 5 minutes, then slowly add 8wt% (total mass) hydrogenated castor oil emulsion, maintain stirring at 1600 rpm for 2 minutes to form a uniform and stable composite binder system, and cool to below 40℃ before discharging; Step 3: The composite fiber blank is then pressed and pressed with a press machine. First, it is held at 8MPa for 12s, and then at 3MPa for 28s for graded pressurization. After that, the pressure is released, and the edges are trimmed and polished to obtain the inner lining material.

[0017] Comparative Example 1 The difference between Comparative Example 1 and Example 1 is that an equal amount of untreated graphene oxide was used instead of pretreated graphene oxide, while everything else remained the same.

[0018] Comparative Example 2 The difference between Comparative Example 2 and Example 1 is that the composite colloid was prepared by mixing unacetylated lignin and sodium carboxymethyl cellulose at a mass ratio of 3.5:2, while keeping other aspects unchanged.

[0019] Comparative Example 3 The difference between Comparative Example 3 and Example 1 is that an equal amount of solid hydrogenated castor oil was used instead of hydrogenated castor oil emulsion, while everything else remained the same.

[0020] Comparative Example 4 The difference between Comparative Example 4 and Example 1 is that only polylactic acid glycol is used in the composite additive, while the others remain the same.

[0021] Comparative Example 5 The difference between Comparative Example 5 and Example 1 is that the fibers in step 1) are not vacuum dried or activated, but are simply air-dried (moisture content of about 10%), and the molding process in step 3) uses single pressure molding (single pressure holding at 8MPa for 38s) instead of graded pressure, while the others remain unchanged.

[0022] The performance of the lining materials for automobile trunks prepared in the above embodiments and comparative examples was tested as follows: I. Mechanical property testing of inner lining material Mechanical properties are key indicators for evaluating whether automotive interior materials can withstand various external forces (such as tension, bending, and compression) during assembly and use, directly affecting the structural integrity and service life of parts. This test used a universal testing machine (referring to ASTM D638 and ASTM D790 standards) to determine tensile and flexural strength; a Shore D hardness tester (referring to ASTM D2240 standard) to measure material hardness; mercury intrusion porosimetry (referring to ASTM D4404 standard) to measure volumetric porosity; and a fabric permeability tester (referring to ISO 9237 standard) to evaluate air permeability. The test results are shown in Table 1.

[0023] Table 1 Mechanical properties of lining materials

[0024] As shown in Table 1, the lining materials prepared in Examples 1-4 of this invention are significantly superior to all comparative examples in terms of key mechanical properties such as tensile strength, flexural strength, and hardness. This indicates that the formulation system (pretreated graphene oxide, composite binder, composite additives) and preparation process (such as staged pressurization) of this invention can effectively improve the mechanical properties of the material.

[0025] Furthermore, the embodiment exhibits lower volumetric porosity and moderate breathability, indicating a more dense and uniform internal structure. This ensures basic breathability while laying the foundation for excellent durability.

[0026] II. Durability Testing of Inner Lining Material Durability testing is used to evaluate the long-term performance of materials under humid, abrasive, and high-temperature environments, simulating conditions that may be encountered in real-world vehicle use, such as moisture, friction from objects, and exposure to high temperatures in summer. This test uses the immersion method (referring to ASTM D570) to measure 24-hour water absorption; abrasion resistance is evaluated using a Taber abrasion tester (referring to ASTM D4060), expressed as weight loss; and the 5% thermogravimetric analysis (TGA, referring to ISO 11358) is used to determine the 5% thermogravimetric temperature under a nitrogen atmosphere. The test results are shown in Table 2.

[0027] Table 2

[0028] As shown in Table 2, the lining material of this invention exhibits excellent durability in terms of water resistance, abrasion resistance, and thermal stability. Regarding water resistance and abrasion resistance, Example 1 shows one of the lowest 24-hour water absorption rates (<4.5%) and abrasion amounts (<12 mg). This is directly related to its dense microstructure (low porosity). The robust interface formed by the pretreated graphene oxide and the composite binder effectively blocks water penetration and resists abrasion. Comparative Examples 2, 3, and 5, due to poor compatibility or loose structure, show a sharp increase in water absorption and abrasion amounts.

[0029] In terms of thermal stability, Example 1 exhibited a 5% thermogravimetric temperature as high as 292°C, significantly higher than most comparative examples. This is attributed to the inherent high-temperature resistance of zirconia ceramic fibers, the thermal stabilizing effect of pretreated graphene oxide, and the good thermal stability of the composite binder system. Comparative Examples 3 and 2 showed the lowest thermal decomposition temperatures, indicating that imperfections in the binder system directly reduce the overall thermal stability of the material. Comparative Example 5 also exhibited poor thermal stability due to its porous structure.

[0030] III. Anti-mildew and antibacterial performance test of inner lining material The enclosed and humid environment of a car trunk is prone to the growth of mold and bacteria, which not only produce odors and contaminate items, but may also affect the health of passengers. Therefore, it is crucial to conduct anti-mold and antibacterial tests on interior materials. This test used the film coating method (referring to ISO 846 standard) to determine the anti-mold property against Aspergillus niger, and the film application method (referring to JIS Z 2801 standard) to determine the antibacterial property against Escherichia coli and Staphylococcus aureus, expressed as the inhibition rate; the total volatile organic compound (TVOC) content was determined using thermal desorption-gas chromatography / mass spectrometry (TD-GC / MS, referring to VDA 278 standard). The test results are shown in Table 3.

[0031] Table 3 Anti-mildew and antibacterial properties of lining materials

[0032] As shown in Table 3, the lining material of this invention possesses excellent and long-lasting antifungal and antibacterial capabilities while meeting environmental protection and low volatility requirements. Regarding antibacterial efficacy, the examples showed a 24-hour inhibition rate exceeding 96% against all three test strains, achieving a highly efficient antibacterial level. This is mainly attributed to the continuous release and synergistic effect of calcium propionate (antifungal agent) and cerium nitrate (antibacterial agent) loaded on the pretreated graphene oxide, as well as the natural antibacterial contribution of hydroxyethyl cashew nutshell oil ether in the composite additives. The inhibition rate of Comparative Example 1 (untreated graphene oxide) plummeted, demonstrating that functional pretreatment is the source of antibacterial activity. Comparative Example 5 exhibited the lowest inhibition rate because its porous structure not only provided a hiding place for microorganisms but may also have led to the loss of antibacterial components. Simultaneously, it had the highest TVOC, indicating that poor processing can cause small molecules to volatilize more easily. The antibacterial rates of Comparative Examples 2, 3, and 4 all decreased, while TVOC increased, indicating that the complete binder and additive system makes an important contribution to building a dense surface (reducing microbial adhesion) and coating low molecular weight substances (reducing VOC).

[0033] IV. Antistatic Performance Testing of Lining Material Static electricity not only attracts dust, making cleaning difficult, but can also generate electric sparks in dry environments, posing a safety hazard. Testing antistatic properties is a crucial part of evaluating automotive interior materials. This test uses a triboelectric generator (referencing ISO 18080 standard) to measure surface triboelectric voltage; a high-resistance meter (referencing IEC 61340-5-1 standard) to measure surface resistance; and a static electricity decay tester (referencing ESD STM11.13 standard) to record voltages from 10... 5 V decays to 10 3 The time required for V. The test results are shown in Table 4.

[0034] Table 4 Antistatic Performance Test of Lining Material

[0035] As shown in Table 4, the lining material of this invention exhibits rapid and durable antistatic properties, likely due to the well-developed and uniform conductive network formed within the material by the carbon fibers and pretreated graphene oxide. The pretreatment improves the dispersion of graphene oxide, which, in synergy with the carbon fibers, ensures that the charge can be rapidly conducted away.

[0036] The surface resistivity of comparative examples 1, 3, and 5 is as high as 10. 12 The attenuation time exceeded 3 seconds, indicating that graphene pretreatment, hydrogenated castor oil emulsion, and graded pressurization process are crucial for constructing an effective conductive pathway. The antistatic properties of Comparative Examples 2 and 4 were acceptable, but still inferior to the examples, demonstrating that the complete composite colloid and composite additive system contributes to the uniform distribution of conductive components on the fiber surface.

[0037] In summary, the anti-mildew and antistatic automotive trunk lining material and its preparation method of this invention achieve an optimal balance between mechanical strength, durability, anti-mildew and antistatic properties, and environmental friendliness, meeting the application requirements of automotive trunk linings. Through key component selection and a graded pressurization process, a microstructure with low porosity and high interfacial bonding strength is successfully constructed, resulting in extremely low water absorption, excellent wear resistance (no surface damage), and good thermal stability, leading to a long service life. Furthermore, the material possesses highly efficient and broad-spectrum antibacterial properties (antibacterial rate >96%) while achieving ultra-low VOC release. Based on a stable conductive network constructed from pretreated graphene oxide and carbon fibers, the material exhibits rapid and sustained electrostatic dissipation capabilities, effectively preventing dust adsorption. This invention provides a high-performance lining material with high practical application value.

Claims

1. A mildew-proof and antistatic automotive trunk lining material, characterized in that, It contains the following components by weight: 2-3 parts pretreated graphene oxide, 20-30 parts bast fiber, 35-40 parts zirconia ceramic fiber, 8-16 parts carbon fiber, 8-11 parts composite binder, 6-9 parts stearic acid, and 3-5 parts composite additives.

2. The anti-mildew and antistatic automotive trunk lining material according to claim 1, characterized in that, The preparation of the pretreated graphene oxide includes the following steps: immersing graphene oxide in a phosphate solution containing 20-30 wt% calcium propionate at a solid-liquid ratio of (2-4):(11-15) g / mL, with a pH of 5.5-7.0, adding 10-20 wt% cerium nitrate for dispersion and drying to obtain pretreated graphene oxide.

3. The anti-mildew and antistatic automotive trunk lining material according to claim 1, characterized in that, The preparation of the composite adhesive includes the following steps: 1) Hydrogenated castor oil emulsification: Hydrogenated castor oil is melted at 90-95℃, and an equal amount of alkyl glycoside and deionized water are added. The mixture is then subjected to high-speed shearing to prepare a hydrogenated castor oil emulsion, which is then cooled to room temperature for later use. 2) Preparation of composite colloid: Add acetylated lignin, hydroxypropyl methylcellulose, and sodium carboxymethyl cellulose to deionized water and stir at 60-70℃ for 30 minutes until completely dissolved to form a homogeneous colloid; 3) Preparation of composite binder: Keep the temperature at 70~80℃, increase the speed to 2500-3000 rpm and stir at high speed for 4-6 minutes. Then slowly add 6~10 wt% hydrogenated castor oil emulsion and stir at 1000~2000 rpm for 1-3 minutes. Then cool and discharge to obtain composite binder.

4. The anti-mildew and antistatic automotive trunk lining material according to claim 3, characterized in that, The acetylated lignin, hydroxypropyl methylcellulose, and sodium carboxymethyl cellulose are mixed in a mass ratio of (3-4):(10-12):(2-3) and added to deionized water at a material-to-liquid ratio of 1:(2-3) mg / mL.

5. The anti-mildew and antistatic automotive trunk lining material according to claim 1, characterized in that, The acetylated lignin is prepared by mixing lignin and acetic anhydride at a mass ratio of (10~15):(3~5), heating to 60~70℃ and stirring to carry out acetylation, and then pulverizing after vacuum drying for later use.

6. The anti-mildew and antistatic automotive trunk lining material according to claim 1, characterized in that, The composite additive comprises polylactic acid glycol and hydroxyethyl cashew nut shell oil ether in a mass ratio of 20-30:5-10.

7. A method for preparing the anti-mildew and antistatic automotive trunk lining material according to any one of claims 1-6, characterized in that, Includes the following steps: Step 1: Vacuum dry and activate the bast fiber, zirconia ceramic fiber and carbon fiber respectively to achieve a moisture content of ≤3%; The pretreated graphene oxide was mixed with the three types of fibers mentioned above and stirred at high speed until homogeneous. Step 2: Heat the composite adhesive to 50~60℃, add stearic acid and composite additives and mix well. Spray evenly onto the mixture in Step 1), stirring while spraying. After completion, cold press to form the composite fiber preform. Step 3: Next, press the composite fiber blank into a mold. Use a press machine to hold the pressure at 6-10 MPa for 10-15 seconds, then hold the pressure at 3-4 MPa for 20-30 seconds for graded pressurization. Finally, release the pressure and perform edge trimming and polishing to obtain the inner lining material.

8. The method for preparing the anti-mildew and antistatic automobile trunk lining material according to claim 7, characterized in that, The cold pressing temperature is 5~10℃, the pressure is 8~10MPa, and the time is 30s~1min.

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