A mildew-proof and antibacterial composite material and its preparation method

Abstract

This application relates to the technical field of automotive interior processing, and specifically discloses a mildew-proof and antibacterial composite material and a preparation method thereof. A mildew-proof and antibacterial composite material and a preparation method thereof include a non-woven fabric, an impregnated film, a blended fiber felt, and an impregnated film that are sequentially laminated. The blended fiber felt comprises raw materials in the following mass percentages: 40-60% sisal fiber and 40-60% modified polypropylene fiber; the impregnated film is a mildew-proof and antibacterial agent-modified polypropylene impregnated film; in addition, the preparation method of this application has the advantage of improving the mildew-proof and antibacterial properties of automotive interior materials.

Description

Technical Field

[0001] This application relates to the technical field of automotive interior processing, and more specifically, it relates to a mildew-proof and antibacterial composite material and a preparation method thereof. Background Art

[0002] With the increasingly strict environmental protection regulations and consumers' urgent need for healthy and sustainable materials, automotive interior materials are gradually transforming towards degradable and renewable directions. Although traditional polyurethane-based composite materials have excellent mechanical strength and wear resistance, they have problems of non-degradability and difficult recycling.

[0003] In recent years, natural fibers, such as hemp fibers, bamboo fibers, coconut shell fibers, etc., have been introduced into the automotive interior field due to their low carbon emissions and renewable characteristics. However, single natural fibers cannot meet the comprehensive performance requirements of automotive interior materials, and the compatibility between natural fibers and polymer polymers is poor. The obtained composite fibers are prone to drainage difficulties due to the hygroscopicity of natural fibers and the hydrophobicity of polymer polymers, and mildew is likely to occur inside the material and at the composite interface, which is not conducive to the use of the material. Summary of the Invention

[0004] In order to improve the mildew-proof and antibacterial performance of automotive interior materials, this application provides a mildew-proof and antibacterial composite material and a preparation method thereof.

[0005] In a first aspect, this application provides a mildew-proof and antibacterial composite material, adopting the following technical solution:

[0006] A mildew-proof and antibacterial composite material includes a non-woven fabric, an impregnated film, a blended fiber felt, and an impregnated film that are sequentially compounded. The blended fiber felt includes raw materials in the following mass percentages: 40 - 60% sisal fiber, 40 - 60% modified polypropylene fiber; the impregnated film is a mildew-proof and antibacterial agent-modified polypropylene impregnated film.

[0007] By adopting the above technical solution, natural fibers and modified polypropylene fibers are mixed to prepare a fiber felt, effectively reducing the water absorption performance of the blended fiber felt and the moisture content of the composite material during use, thereby improving the mildew-proof performance of the mixed material. At the same time, the modified polypropylene fiber can improve the bonding strength between the blended fiber felt and the impregnated film. The impregnated film is a mildew-proof and antibacterial agent-modified polypropylene impregnated film, which has high mildew-proof and antibacterial performance. The impregnated film has high antibacterial performance and hydrophobicity, thereby realizing the improvement of the mildew-proof and antibacterial performance of the composite material.

[0008] Preferably, the preparation method of the modified polypropylene fiber comprises the following steps: mixing the antibacterial particles with the polypropylene chips, and then performing melt spinning, with a spinneret diameter of 0.5-0.6 mm, a spinning rate of 110-120 m / min, a spinning temperature of 190-230°C, a stretching temperature of 80°C, a stretching multiple of 4-6, and a heat setting temperature of 100°C.

[0009] By adopting the above technical scheme, the antibacterial particles have good antibacterial properties and thermal stability, and can be mixed with polypropylene chips and then spun. The modified polypropylene fibers obtained by melt spinning have good strength and antibacterial properties, and are also hydrophobic. After being mixed with natural fibers, the mixed fiber felt has good antibacterial properties.

[0010] Preferably, the added amount of the antibacterial particles is 1.37-2.18wt% of the polypropylene slices, and the antibacterial particles are titanium dioxide microspheres loaded with nano zinc oxide.

[0011] By adopting the above technical scheme, both titanium dioxide and zinc oxide have good antibacterial properties, can interfere with the growth activities of microorganisms or bacteria under light or no light conditions, and improve the antibacterial properties of modified polypropylene fibers. At the same time, as inorganic particles, they have good thermal stability and can exist relatively stably in the preparation process of modified polypropylene fibers.

[0012] Preferably, the preparation method of the antibacterial particles comprises the following steps: mixing 85-90 mL of isopropanol with 22-25 mL of acetone, adding dropwise 2.2-2.5 mL of titanium chloride ultrasonically dispersed with nano-zinc oxide while stirring, magnetically stirring for 30 minutes, ultrasonicating for 5 minutes, performing a hydrothermal reaction at 200-220° C. for 12 hours, naturally cooling, precipitating, washing, drying, and heat treating at 550-560° C. for 2 hours to obtain the antibacterial particles.

[0013] By adopting the above technical scheme, nano-titanium dioxide microspheres with better shape and moderate size are obtained by hydrothermal method. Nano-zinc oxide is dispersed in titanium chloride. In the process of forming microspheres by hydrothermal reaction, nano-zinc oxide is fixed in the antibacterial particles along with titanium dioxide, thereby realizing the loading of nano-zinc oxide.

[0014] Preferably, the added amount of the nano zinc oxide is 15.26-20.68wt% of the titanium chloride.

[0015] By adopting the above technical scheme, the addition amount of nano zinc oxide is controlled so that the nano zinc oxide can be evenly dispersed in titanium chloride and finally evenly loaded in titanium dioxide microspheres. At the same time, zinc oxide can synergistically exert antibacterial properties with titanium dioxide, thereby improving the antibacterial properties of modified polypropylene fibers.

[0016] Preferably, the preparation method of the impregnated membrane comprises the following steps: impregnate a polypropylene membrane in an acetone solution of maleic anhydride, and after ultraviolet light irradiation, obtain a polypropylene membrane with surface photo-grafting, then immerse it in a silver nitrate solution for 50 s, rinse it with clear water for 40 s, and then immerse it in a sodium chloride solution for 50 s. Repeat the impregnation operation 8-10 times, and then obtain the impregnated membrane after natural drying.

[0017] By adopting the above technical solution, maleic anhydride is grafted onto the polypropylene membrane through ultraviolet light irradiation. The grafting of maleic anhydride can effectively improve the adhesion of the polypropylene membrane, thereby providing good deposition and adsorption conditions for silver chloride precipitation in the subsequent impregnation process, promoting the smooth and perfect deposition of the silver chloride layer on the surface of the polypropylene membrane. After the impregnated membrane is compounded with the blended fiber felt, the silver in the impregnated membrane synergistically interacts with zinc oxide and titanium dioxide in the modified polypropylene fiber, so that at the interface between the blended fiber felt and the impregnated membrane, this part where bacteria are prone to grow and mildew has higher antibacterial properties, thereby improving the overall mildew and antibacterial properties of the composite material.

[0018] Preferably, the ultraviolet light irradiation time is 160-180 s, the wavelength is 254 nm, and the intensity is 8500-9000 μW / cm 2 。

[0019] By adopting the above technical solution, the irradiation time, wavelength and intensity of ultraviolet light are controlled, so as to ensure the grafting effect and grafting amount of maleic anhydride, make the polypropylene membrane have good adhesion, and further ensure the antibacterial properties of the impregnated membrane.

[0020] In the second aspect, the present application provides a preparation method of a mildew and antibacterial composite material, adopting the following technical solution:

[0021] A preparation method of a mildew and antibacterial composite material comprises the following steps: card, mix, lay and needle sisal fiber and modified polypropylene fiber to obtain a blended fiber felt. After laminating non-woven fabric, impregnated membrane, blended fiber felt and impregnated membrane in sequence, perform plate making through a roll pressing process at 150 °C to obtain a mildew and antibacterial composite material.

[0022] By adopting the above technical solution, sisal fiber and modified polypropylene fiber are mixed to obtain a blended fiber felt, which reduces the water absorption performance of the blended fiber felt, thereby reducing the water absorption amount of the composite material during use, and further improving its mildew resistance. The addition of modified polypropylene fiber can improve the bonding strength between the blended fiber felt and the impregnated membrane during plate making.

[0023] To sum up, the present application has the following beneficial effects:

[0024] 1. Since this application mixes natural fibers with modified polypropylene fibers to obtain a fiber felt, it effectively reduces the water absorption performance of the blended fiber felt, decreases the moisture content of the composite material during use, thereby improving the mildew resistance of the composite material. At the same time, the modified polypropylene fiber can improve the bonding strength between the blended fiber felt and the impregnation film. The impregnation film is a polypropylene impregnation film modified with a mildew and antibacterial agent, which has high mildew and antibacterial properties. The impregnation film has high antibacterial properties and hydrophobicity, thus realizing the improvement of the mildew and antibacterial properties of the composite material.

[0025] 2. In this application, the antibacterial particles have good antibacterial properties and thermal stability, and can be mixed with polypropylene chips for spinning. The modified polypropylene fibers prepared by melt spinning have good strength and antibacterial properties, and at the same time have hydrophobicity. After being mixed with natural fibers, the blended fiber felt has good antibacterial properties.

[0026] 3. In this application, maleic anhydride is grafted onto the polypropylene film by ultraviolet light irradiation. The maleic anhydride grafting can effectively improve the adhesion of the polypropylene film, thus providing good deposition and adsorption conditions for silver chloride precipitation in the subsequent impregnation process, promoting the smooth and perfect deposition of the silver chloride layer on the surface of the polypropylene film. After the impregnation film is compounded with the blended fiber felt, the silver in the impregnation film synergizes with zinc oxide and titanium dioxide in the modified polypropylene fiber, so that at the interface between the blended fiber felt and the impregnation film, this part that is prone to mildew and bacteria growth has higher antibacterial properties, thereby improving the overall mildew and antibacterial properties of the composite material. Specific embodiments

[0027] The following further elaborates on this application in conjunction with embodiments.

[0028] Preparation examples 1 - 5 of antibacterial particles

[0029] Preparation example 1

[0030] The preparation method of antibacterial particles includes the following steps: Mix 85 mL of isopropanol with 22 mL of acetone, and while stirring, dropwise add 2.2 mL of titanium chloride ultrasonically dispersed with nano - zinc oxide. The addition amount of nano - zinc oxide is 20.68 wt% of titanium chloride. After magnetic stirring for 30 min and ultrasonic treatment for 5 min, carry out hydrothermal reaction at 200 °C for 12 h, then naturally cool, precipitate, wash, dry, and perform heat treatment at 550 °C for 2 h to obtain antibacterial particles.

[0031] Preparation example 2

[0032] Method for preparing antibacterial particles, comprising the following steps: Mix 90 mL of isopropanol with 25 mL of acetone, and while stirring, dropwise add 2.5 mL of titanium chloride ultrasonically dispersed with nano-zinc oxide. The addition amount of nano-zinc oxide is 15.26 wt% of titanium chloride. After magnetic stirring for 30 min and ultrasonic treatment for 5 min, perform hydrothermal reaction at 220 °C for 12 h, then naturally cool, precipitate, wash, dry, and perform heat treatment at 560 °C for 2 h to obtain antibacterial particles.

[0033] Preparation Example 3

[0034] The difference between Preparation Example 3 and Preparation Example 1 is that in Preparation Example 3, the addition amount of nano-zinc oxide is 5.95 wt% of titanium chloride.

[0035] Preparation Example 4

[0036] The difference between Preparation Example 4 and Preparation Example 1 is that in Preparation Example 4, the addition amount of nano-zinc oxide is 30.25 wt% of titanium chloride.

[0037] Preparation Example 5

[0038] The difference between Preparation Example 5 and Preparation Example 1 is that in Preparation Example 5, nano-zinc oxide is not added to titanium chloride.

[0039] Preparation Examples 6 - 13 of modified polypropylene fibers

[0040] Preparation Example 6

[0041] Method for preparing modified polypropylene fibers, comprising the following steps: Mix antibacterial particles with polypropylene chips. The addition amount of antibacterial particles is 1.37 wt% of polypropylene chips, perform melt spinning, the spinneret diameter is 0.5 mm, the spinning speed is 110 m / min, the spinning temperature is 190 °C, the drawing temperature is 80 °C, the drawing ratio is 4, the heat setting temperature is 100 °C, and the antibacterial particles are the antibacterial particles obtained in Preparation Example 1.

[0042] Preparation Example 7

[0043] Method for preparing modified polypropylene fibers, comprising the following steps: Mix antibacterial particles with polypropylene chips. The addition amount of antibacterial particles is 2.18 wt% of polypropylene chips, perform melt spinning, the spinneret diameter is 0.6 mm, the spinning speed is 120 m / min, the spinning temperature is 230 °C, the drawing temperature is 80 °C, the drawing ratio is 6, the heat setting temperature is 100 °C, and the antibacterial particles are the antibacterial particles obtained in Preparation Example 2.

[0044] Preparation Example 8

[0045] The difference between Preparation Example 8 and Preparation Example 6 is that in Preparation Example 8, the antibacterial particles are the antibacterial particles obtained in Preparation Example 3.

[0046] Preparation Example 9

[0047] The difference between Preparation Example 9 and Preparation Example 6 is that in Preparation Example 9, the antibacterial particles used are the antibacterial particles prepared in Preparation Example 4.

[0048] Preparation Example 10

[0049] The difference between Preparation Example 10 and Preparation Example 6 is that in Preparation Example 10, the antibacterial particles used are the antibacterial particles prepared in Preparation Example 5.

[0050] Preparation Example 11

[0051] The difference between Preparation Example 11 and Preparation Example 6 is that in Preparation Example 11, the addition amount of the antibacterial particles is 0.52 wt% of the polypropylene chips.

[0052] Preparation Example 12

[0053] The difference between Preparation Example 12 and Preparation Example 6 is that in Preparation Example 12, the addition amount of the antibacterial particles is 4.95 wt% of the polypropylene chips.

[0054] Preparation Example 13

[0055] The difference between Preparation Example 13 and Preparation Example 6 is that in Preparation Example 13, no antibacterial particles are added.

[0056] Preparation Examples 14 - 15 of the impregnated film

[0057] Preparation Example 14

[0058] The preparation method of the impregnated film includes the following steps: Immerse the polypropylene film in an acetone solution of maleic anhydride, and after ultraviolet light irradiation, obtain the polypropylene film with surface photo - grafting. The ultraviolet light irradiation time is 160 s, the wavelength is 254 nm, and the intensity is 9000 μW / cm 2 , then immerse it in a silver nitrate solution for 50 s, rinse it with clear water for 40 s, then immerse it in a sodium chloride solution for 50 s, repeat the impregnation operation 8 times, and obtain the impregnated film after natural drying.

[0059] Preparation Example 15

[0060] The preparation method of the impregnated film includes the following steps: Immerse the polypropylene film in an acetone solution of maleic anhydride, and after ultraviolet light irradiation, obtain the polypropylene film with surface photo - grafting. The ultraviolet light irradiation time is 180 s, the wavelength is 254 nm, and the intensity is 8500 μW / cm 2 , then immerse it in a silver nitrate solution for 50 s, rinse it with clear water for 40 s, then immerse it in a sodium chloride solution for 50 s, repeat the impregnation operation 10 times, and obtain the impregnated film after natural drying. Examples

[0061] Example 1

[0062] A mildew-proof and antibacterial composite material, comprising a non-woven fabric, an impregnated film, a blended fiber felt and an impregnated film which are sequentially compounded. The blended fiber felt comprises raw materials in the following mass percentages: 40% sisal fiber and 60% modified polypropylene fiber, and the modified polypropylene fiber is the modified polypropylene fiber prepared in Preparation Example 6; the impregnated film is a mildew-proof and antibacterial agent modified polypropylene impregnated film, and the impregnated film is the impregnated film prepared in Preparation Example 14.

[0063] The preparation method of the above-mentioned mildew-proof and antibacterial composite material comprises the following steps: carding, mixing, web laying and needling the sisal fiber and the modified polypropylene fiber to obtain a blended fiber felt, laminating the non-woven fabric, the impregnated film, the blended fiber felt and the impregnated film in sequence, and then performing plate making by a roll pressing process at 150 °C to obtain the mildew-proof and antibacterial composite material.

[0064] Example 2

[0065] A mildew-proof and antibacterial composite material, comprising a non-woven fabric, an impregnated film, a blended fiber felt and an impregnated film which are sequentially compounded. The blended fiber felt comprises raw materials in the following mass percentages: 60% sisal fiber and 40% modified polypropylene fiber, and the modified polypropylene fiber is the modified polypropylene fiber prepared in Preparation Example 7; the impregnated film is a mildew-proof and antibacterial agent modified polypropylene impregnated film, and the impregnated film is the impregnated film prepared in Preparation Example 15.

[0066] The preparation method of the above-mentioned mildew-proof and antibacterial composite material comprises the following steps: carding, mixing, web laying and needling the sisal fiber and the modified polypropylene fiber to obtain a blended fiber felt, laminating the non-woven fabric, the impregnated film, the blended fiber felt and the impregnated film in sequence, and then performing plate making by a roll pressing process at 150 °C to obtain the mildew-proof and antibacterial composite material.

[0067] Example 3

[0068] The difference between Example 3 and Example 1 is that in Example 3, the modified polypropylene fiber is the modified polypropylene fiber prepared in Preparation Example 8.

[0069] Example 4

[0070] The difference between Example 4 and Example 1 is that in Example 4, the modified polypropylene fiber is the modified polypropylene fiber prepared in Preparation Example 9.

[0071] Example 5

[0072] The difference between Example 5 and Example 1 is that in Example 5, the modified polypropylene fiber is the modified polypropylene fiber prepared in Preparation Example 10.

[0073] Example 6

[0074] Example 6 is different from Example 1 in that in Example 6, the modified polypropylene fiber is the modified polypropylene fiber prepared in Preparation Example 11.

[0075] Example 7

[0076] Example 7 is different from Example 1 in that in Example 7, the modified polypropylene fiber is the modified polypropylene fiber prepared in Preparation Example 12.

[0077] Example 8

[0078] Example 8 is different from Example 1 in that in Example 8, the modified polypropylene fiber is the modified polypropylene fiber prepared in Preparation Example 13. Comparative Example

[0079] Comparative Example 1

[0080] Comparative Example 1 is different from Example 1 in that in Comparative Example 1, a polypropylene film is used instead of the impregnated film.

[0081] Comparative Example 2

[0082] Comparative Example 2 is different from Example 1 in that in Comparative Example 2, in the blended fiber mat, the mass percentage of sisal fiber is 20%.

[0083] Comparative Example 3

[0084] Comparative Example 3 is different from Example 1 in that in Comparative Example 3, in the blended fiber mat, the mass percentage of sisal fiber is 80%.

[0085] Performance Detection Test

[0086] According to the preparation raw materials and preparation methods of Examples 1-8 and Comparative Examples 1-3, a mildew-proof and antibacterial composite material was prepared. The sample area was 100 mm × 100 mm. The sample was suspended in a closed test chamber. There was 200 mL of clear water placed at the bottom of the closed test chamber. The distance between the sample and the water surface was 15 cm. The temperature of the closed test chamber was 40 ± 5 °C, and the humidity was 90 ± 5%. The test time for the sample was 14 d. After the test was over, the closed test chamber was opened, and it was smelled whether there was a musty smell in the test chamber. Then, it was observed whether there was mildew growth on the surface of the non-woven fabric, and whether there was mildew growth at the interface between the blended fiber mat and the impregnated film and on the blended fiber mat. The observation results were recorded in Table 1.

[0087] Table 1 Mildew-proof and Antibacterial Performance Test

[0088] Project Mildew smell Surface mildew Interface mildew Fiber felt mildew Example 1 No No No No Example 2 No No No No Example 3 Yes No Yes Yes Example 4 Yes No Yes Yes Example 5 Yes No Yes Yes Example 6 Yes No Yes Yes Example 7 Yes No Yes Yes Example 8 Yes No Yes Yes Comparative Example 1 Yes No Yes No Comparative Example 2 Yes No Yes Yes Comparative Example 3 Yes No No Yes

[0089] It can be seen from Table 1, Examples 1-2 and Comparative Examples 1-3 that there was no mildew on the surface of the specimens, the blended fiber felt and the interface in Examples 1-2, and there was no musty smell inside the test chamber, indicating that the composite materials prepared in Examples 1-2 had high anti-mildew and antibacterial properties. However, mildew appeared at the interface in Comparative Example 1, mildew appeared on both the blended fiber felt and the interface in Comparative Example 2, and mildew appeared on the blended fiber felt in Comparative Example 3. In Comparative Example 1, a polypropylene film was used instead of the impregnated film, and the polypropylene film was not treated with silver chloride precipitation coating, resulting in a decrease in the anti-mildew and antibacterial properties of the composite material. At the same time, there were only antibacterial particles at the interface, and there was no synergistic antibacterial effect between silver chloride and zinc oxide and titanium dioxide, so the antibacterial property at the interface decreased compared with Examples 1-2, and mildew grew at the interface. In Comparative Examples 2-3, the mass percentages of sisal fiber and modified polypropylene fiber were changed. In Comparative Example 2, the content of sisal fiber was too high, and the content of modified polypropylene fiber decreased, resulting in a decrease in the composite strength of the blended fiber felt and the impregnated film and a decrease in the bonding degree at the interface. The water absorption was good, and too much water was absorbed and stored in the blended fiber felt during the experiment, which was easy to breed mildew. In Comparative Example 3, the content of sisal fiber decreased, the content of modified polypropylene fiber increased, the water absorption of the blended fiber felt decreased, local water storage appeared inside, and the water loss was difficult, resulting in mildew.

[0090] In Examples 1-2, antibacterial particles were added to the modified polypropylene fiber. Both zinc oxide and titanium dioxide in the antibacterial particles had good antibacterial properties, which could inhibit the growth and reproduction of molds and bacteria in the material and achieve the anti-mildew and antibacterial effect. At the same time, at the interface between the blended fiber felt and the impregnated film, the antibacterial particles could synergistically prevent mildew and antibacterial with the silver chloride layer coated on the surface of the impregnated film, further improving the anti-mildew and antibacterial properties at the interface. At the same time, the modified polypropylene fiber improved the bonding strength between the blended fiber felt and the impregnated film, improved the compatibility and bonding tightness at the interface, and reduced the water storage at the interface, thus improving the anti-mildew and antibacterial properties of the composite material.

[0091] Compared with Example 1, in Examples 3-4, when preparing the antibacterial particles, the addition amount of nano-zinc oxide was changed, and mildew appeared at the interface and on the mixed fiber felt. The addition amount of nano-zinc oxide affected the dispersion of nano-zinc oxide in titanium chloride. If the addition amount was too much, nano-zinc oxide was easily unevenly dispersed, resulting in a decrease in the loading of nano-zinc oxide on the titanium dioxide microspheres and a decrease in the content of nano-zinc oxide in the antibacterial particles, which affected the antibacterial property of the antibacterial particles. If the addition amount was too little, the synergistic antibacterial property of nano-zinc oxide, titanium dioxide and silver chloride decreased, resulting in a decrease in the anti-mildew and antibacterial properties of the composite material.

[0092] Compared with Example 1, in the preparation of the antibacterial particles in Example 5, nano-zinc oxide was not added, that is, the antibacterial particles were titanium dioxide microspheres. Mildew occurred at the interface and the blended fiber felt in Example 5, indicating that the addition of nano-zinc oxide can effectively improve the anti-mildew and antibacterial properties of the composite material. Without the addition of nano-zinc oxide, the anti-mildew and antibacterial properties of the antibacterial particles decreased, and at the same time, the synergistic effect between the antibacterial particles and the impregnated membrane weakened, thus reducing the anti-mildew and antibacterial properties at the interface and resulting in mildew.

[0093] Compared with Example 1, in the preparation of the modified polypropylene fibers in Examples 6-8, the addition amount of the antibacterial particles was changed. The polypropylene fibers used in Example 8 did not contain antibacterial particles. Mildew occurred at the interface and the blended fiber felt in Examples 6-8, indicating that the addition amount of the antibacterial particles affected the antibacterial properties of the composite material. When the addition amount of the antibacterial particles was reduced or not added, the anti-mildew and antibacterial properties of the blended fiber felt decreased. When the addition amount of the antibacterial particles increased, it was easy for the antibacterial particles to be unevenly dispersed in the modified polypropylene fibers, affecting the spinning performance of the modified polypropylene fibers and at the same time affecting the anti-mildew and antibacterial properties of the modified polypropylene fibers.

[0094] This specific embodiment is only an interpretation of the present application and does not limit the present application. After reading this specification, those skilled in the art can make modifications to this embodiment without creative contributions as needed, but as long as they are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. A mold and mildew resistant and antibacterial composite material, characterized in that: It includes a non-woven fabric, an impregnated film, a blended fiber felt and an impregnated film which are compounded in sequence. The blended fiber felt comprises raw materials in the following mass percentages: 40-60% sisal fiber and 40-60% modified polypropylene fiber; The preparation method of the modified polypropylene fiber comprises the following steps: after mixing antibacterial particles with polypropylene chips, melt spinning is carried out, the spinneret diameter is 0.5-0.6 mm, the spinning rate is 110-120 m / min, the spinning temperature is 190-230 °C, the drawing temperature is 80 °C, the drawing ratio is 4-6, and the heat setting temperature is 100 °C. The impregnated film is a polypropylene impregnated film modified with a mildew-proof and antibacterial agent. The preparation method of the impregnated film comprises the following steps: impregnating a polypropylene film in an acetone solution of maleic anhydride, irradiating with ultraviolet light to obtain a surface photo-grafted polypropylene film, then immersing it in a silver nitrate solution for 50 s, rinsing with clear water for 40 s, then immersing it in a sodium chloride solution for 50 s, repeating the impregnation operation 8-10 times, and drying naturally to obtain the impregnated film.

2. The anti-mildew and antibacterial composite material according to claim 1, wherein: The addition amount of the antibacterial particles is 1.37-2.18 wt% of the polypropylene chips, and the antibacterial particles are titanium dioxide microspheres loaded with nano zinc oxide.

3. The anti-mildew and antibacterial composite material according to claim 2, characterized in that: The preparation method of the antibacterial particles comprises the following steps: mixing 85-90 mL of isopropanol with 22-25 mL of acetone, dropwise adding 2.2-2.5 mL of titanium chloride ultrasonically dispersed with nano zinc oxide while stirring, magnetically stirring for 30 min and then ultrasonically for 5 min, carrying out a hydrothermal reaction at 200-220 °C for 12 h, naturally cooling, precipitating, washing and drying, and then heat-treating at 550-560 °C for 2 h to obtain the antibacterial particles.

4. The anti-mildew and antibacterial composite material according to claim 3, characterized in that: The addition amount of the nano zinc oxide is 15.26-20.68 wt% of the titanium chloride.

5. The anti-mildew and antibacterial composite material according to claim 1, wherein: The ultraviolet light irradiation time is 160 - 180 s, the wavelength is 254 nm, and the intensity is 8500 - 9000 μW / cm 2 .

6. The preparation method of a mildew-proof and antibacterial composite material according to any one of claims 1-5, characterized in that: It includes the following steps: Combing, mixing, laying and needling the sisal fiber and the modified polypropylene fiber to obtain a blended fiber felt. After laminating the non-woven fabric, the impregnated film, the blended fiber felt and the impregnated film in sequence, plate making is carried out by a roll pressing process at 150 °C to obtain a mildew-proof and antibacterial composite material.