MOFs modified polypropylene melt-blown nonwoven fabric and preparation method thereof

Abstract

The present invention relates to the technical field of flame retardant and antibacterial materials, in particular to MOFs modified polypropylene melt-blown non-woven fabric and a preparation method thereof. Sodium alginate is added to deionized water and stirred at 25-80°C for 2-6 hours to dissolve to obtain a sodium alginate solution. ZIF-8 is continuously stirred and dispersed in deionized water to obtain a ZIF-8 suspension. Under stirring, the ZIF-8 suspension is added to the sodium alginate solution to uniformly disperse it. The obtained mixed solution is immersed in a calcium chloride aqueous solution and heated at 25-1 The reaction is carried out at 100°C for 2 to 8 hours, the reaction product is filtered and collected, and dried at 60 to 100°C for 3 to 24 hours to obtain CA@ZIF-8. 1 to 8 wt% calcium alginate / ZIF-8, 0.5 to 8 wt% melamine polyphosphate, and 90 to 98 wt% polypropylene are melt-mixed in a twin-screw extruder. The mixture is then fed to a spinneret via a metering pump, blown out by a fan, and laid into a net to obtain a CA@ZIF-8 / MPP / PP flame-retardant and antibacterial melt-blown non-woven fabric. The present invention is used to solve the problems of existing polypropylene materials being flammable and prone to bacterial growth during application.

Description

Technical Field

[0001] The present invention relates to the technical field of flame-retardant and antibacterial materials, and in particular to MOFs-modified polypropylene melt-blown non-woven fabric and a preparation method thereof. Background Art

[0002] Polypropylene (PP) meltblown nonwoven fabrics are often used as the core structure for preparing filter materials such as masks. They are usually made to carry a large amount of static charge through electrostatic charging or water charging to improve filtration efficiency. The limiting oxygen index of polypropylene itself is extremely low, only about 18%. The large amount of static charge carried on its surface can easily trigger fires during storage, transportation and preparation, posing a serious threat to people’s lives and property. On the other hand, while using electrostatic adsorption to improve filtration efficiency, it also allows a large number of microorganisms and bacteria to breed. These microorganisms and bacteria enter the human body directly through the respiratory tract, causing serious damage to people’s bodies. Therefore, the preparation of integrated polypropylene meltblown nonwoven fabrics with flame retardant and antibacterial functions has become a new research hotspot, which can meet the market’s important needs for safety protection and green and healthy textiles.

[0003] Traditional flame retardants are broadly classified into two categories: halogenated and halogen-free. Halogenated flame retardants are gradually being phased out due to their inherent toxicity. Among the many halogen-free flame retardants, phosphorus-nitrogen flame retardants are the most widely used in polymer plastics, thanks to their excellent flame retardancy and relatively low price. For example, invention patent CN113896987A uses pentaerythritol phosphate and melamine as flame retardant additives to prepare polypropylene flame-retardant masterbatch. At an addition level of 14-18 wt%, the flame retardancy reaches V0. However, these flame retardants generally have poor compatibility with polypropylene, and large additions can easily lead to uneven dispersion, thus affecting the material's intrinsic mechanical properties. Commonly used antimicrobial agents can be divided into inorganic and organic antimicrobial agents, with inorganic antimicrobial agents proven to have superior antimicrobial efficacy. The active ingredients of inorganic antimicrobial agents include metallic ions such as silver, zinc, and copper, which can directly interact with cells, disrupting their structure and achieving bactericidal and antimicrobial effects. However, adding metal nanoparticles directly to polymer systems can easily lead to agglomeration, which can seriously affect the material preparation process and the stability of material properties. In addition, metal ions are toxic to a certain extent, and excessive concentrations can harm human health. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide MOFs modified polypropylene melt-blown non-woven fabric and its preparation method and application, which are used to solve the problems of existing polypropylene materials being flammable and prone to bacterial growth during application.

[0005] The present invention solves the above technical problems through the following technical means:

[0006] The first aspect of the present invention is to provide a MOFs modified polypropylene melt-blown non-woven fabric, comprising the following raw materials: calcium alginate / ZIF-81-8wt%, melamine polyphosphate 0.5-8wt%, and polypropylene 90-98wt%.

[0007] In combination with the first aspect, in some embodiments, the MOFs modified polypropylene meltblown non-woven fabric includes the following raw materials: calcium alginate / ZIF-84wt%, melamine polyphosphate 4wt%, and polypropylene 92wt%.

[0008] In combination with the first aspect, in some embodiments, the raw materials for preparing the calcium alginate / ZIF-8 mainly include sodium alginate, ZIF-8, and calcium chloride, and the mass ratio of the sodium alginate, ZIF-8, and calcium chloride is 4-5:5-6.5:9-12.

[0009] The second aspect of the present invention is to provide a method for preparing a MOFs-modified polypropylene melt-blown non-woven fabric, comprising the following steps:

[0010] CA@ZIF-8 was prepared by adding sodium alginate to deionized water and stirring at 25-80°C for 2-6 hours to dissolve to obtain a sodium alginate solution. ZIF-8 was dispersed in deionized water with continuous stirring to obtain a ZIF-8 suspension. The ZIF-8 suspension was added to the sodium alginate solution under magnetic stirring to uniformly disperse the mixture. The obtained mixed solution was immersed in a calcium chloride aqueous solution and reacted at 25-100°C for 2-8 hours. The reaction product was filtered and collected, and dried at 60-100°C for 3-24 hours to obtain CA@ZIF-8.

[0011] CA@ZIF-8 / MPP / PP melt-blown non-woven fabric was prepared by melt-mixing 1-8 wt% calcium alginate / ZIF-8, 0.5-8 wt% melamine polyphosphate and 90-98 wt% polypropylene in a twin-screw extruder. The mixture was then delivered to a spinneret via a metering pump, blown out by a fan and laid into a net, and the CA@ZIF-8 / MPP / PP flame-retardant and antibacterial melt-blown non-woven fabric was collected.

[0012] In combination with the second aspect, in some embodiments, the concentration of the calcium chloride aqueous solution is 30 g / L.

[0013] In combination with the second aspect, in some embodiments, the preparation method of ZIF-8 is as follows: zinc acetate dihydrate is added to a solvent and stirred for 10 to 30 minutes until completely dissolved to obtain a zinc acetate solution, 2-methylimidazole is added to deionized water and stirred for 10 to 30 minutes until completely dissolved to obtain a methylimidazole solution, the methylimidazole solution is added to the zinc acetate solution under magnetic stirring, and then magnetically stirred at 20 to 120°C for 0.5 to 10.0 hours, and then allowed to stand for 6 to 24 hours, the precipitate is collected and dried at 60 to 100°C for 6 to 24 hours to obtain ZIF-8.

[0014] In combination with the second aspect, in some embodiments, the mass ratio of zinc acetate dihydrate to 2-methylimidazole is 0.9 to 1:2.

[0015] In combination with the second aspect, in some embodiments, the mass ratio of sodium alginate, ZIF-8, and calcium chloride is 4-5:5-6.5:9-12.

[0016] In combination with the second aspect, in some embodiments, the screw speed of the twin-screw extruder is 15-50 Hz, and the screw heating temperature is 190-240°C.

[0017] The MOFs modified polypropylene melt-blown nonwoven fabric of the present invention adds CA@ZIF-8 and melamine polyphosphate (MPP) to polypropylene, which improves the flame retardant properties of the polypropylene material while also reducing the impact of poor compatibility and other problems on the intrinsic properties of the polypropylene material. The ZIF-8 also has antibacterial and flame retardant effects. When used as an antibacterial agent, it can slowly and continuously release Zn + , preventing the harmful effects of excessive metal ion release; on the other hand, its porous structure can absorb smoke and toxic gases released during polymer combustion, and its metal ions can catalyze the decomposition of the polymer and other flame retardant components into char, forming a dense protective layer. Calcium alginate (CA) contains a large number of carboxyl and hydroxyl groups. When thermally decomposed, it dehydrates with itself and the phosphoric acid produced by the decomposition of MPP to form an ester, lowering the temperature and forming a dense char layer. It also produces CO2, reducing the concentration of oxidizing and combustible gases. Furthermore, calcium alginate itself contains a large number of phenolic and polysaccharide antimicrobial active ingredients, which can further enhance the antimicrobial properties of the composite material.

[0018] The MOFs-modified polypropylene melt-blown nonwoven fabric of the present invention has excellent flame retardant properties, a limiting oxygen index of up to 30.6%, a vertical burning test (UL 94) reaching V-0 level, and an antibacterial efficiency of over 99%. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is the vertical combustion test process of the MOFs modified polypropylene melt-blown non-woven fabric prepared in Example 1;

[0020] Figure 2 This is the vertical combustion test process of the MOFs modified polypropylene melt-blown nonwoven fabric prepared in Example 2;

[0021] Figure 3 This is the vertical combustion test process of the MOFs modified polypropylene melt-blown nonwoven fabric prepared in Example 3;

[0022] Figure 4 It is a comparison chart of the inhibition zones of pure PP and MOFs modified polypropylene melt-blown non-woven fabrics prepared in Examples 1-3. DETAILED DESCRIPTION

[0023] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0024] In the following examples, if no specific conditions are specified, the experiments were carried out under conventional conditions or those recommended by the manufacturer. All raw materials, equipment, or instruments used, if the manufacturer is not specified, are commercially available conventional products.

[0025] In order to solve the problem that polypropylene materials are flammable and easy to breed bacteria during application, this application proposes a MOFs-modified polypropylene melt-blown non-woven fabric with CA@ZIF-8 and melamine polyphosphate (MPP) added to polypropylene. Under the synergistic effect of CA@ZIF-8, the amount of MPP added can be appropriately reduced, while improving the flame retardant properties of polypropylene materials, it also reduces the impact of problems such as poor compatibility on the intrinsic properties of polypropylene materials. In addition, the ZIF-8 in this application also has antibacterial and flame retardant effects. When used as an antibacterial agent, it can slowly and continuously release Zn + , preventing the harmful effects of excessive metal ion release; on the other hand, its porous structure can absorb smoke and toxic gases released during the polymer combustion process, and its metal ions can catalyze the decomposition of polymers and other flame retardant components into char, forming a dense protective layer. Calcium alginate (CA) contains a large number of carboxyl and hydroxyl groups. When thermally decomposed, it can dehydrate with itself and the phosphoric acid produced by the decomposition of MPP to form an ester, lowering the temperature and forming a dense char layer. At the same time, it produces CO2, reducing the concentration of oxidizing and combustible gases. In addition, calcium alginate itself contains a large number of phenolic and polysaccharide antimicrobial active ingredients, which can further enhance the antimicrobial properties of the composite material.

[0026] The antibacterial flame-retardant polypropylene composite fiber and its preparation method of the present invention are described in detail below through Examples 1-5:

[0027] Example 1

[0028] (1) Synthesis of ZIF-8: 4.5 g of zinc nitrate hexahydrate was added to 50 mL of solvent and stirred for 20 min until completely dissolved, designated as solution A. 10.0 g of 2-methylimidazole was added to 50 mL of deionized water and stirred for 20 min until completely dissolved, designated as solution B. Solution B was added to solution A under magnetic stirring. The mixture was then magnetically stirred at 85°C for 6 h and allowed to stand for 14 h. The precipitate was collected and dried at 100°C for 14 h to obtain the product, ZIF-8.

[0029] (2) Synthesis of CA@ZIF-8: 5.0 g of sodium alginate was dissolved in 50 mL of deionized water with stirring at 60°C for 6 h to obtain solution A. 6.5 g of ZIF-8 was dispersed in 50 mL of deionized water with continuous stirring to obtain solution B. Solution B was added to solution A under magnetic stirring to uniformly disperse the solution, obtaining solution C. Solution C was immersed in 400 mL of a 30 g / L calcium chloride aqueous solution and reacted at 60°C for 4 h. Finally, the reaction product was collected by filtration and dried at 100°C for 14 h to obtain CA@ZIF-8.

[0030] (3) Preparation of CA@ZIF-8 / MPP / PP meltblown nonwoven fabric: 2 wt% CA@ZIF-8, 6 wt% MPP, and 92 wt% PP were melt-mixed in a twin-screw extruder and pumped to a spinneret via a metering pump. The mixture was blown out by a blower and laid into a web. The resulting CA@ZIF-8 / MPP / PP flame-retardant and antibacterial meltblown nonwoven fabric was collected and designated as Sample 1. In this step, the screw speed was 20 Hz, and the screw heating temperatures were 220°C in zone 1, 225°C in zone 2, 225°C in zone 3, and 230°C in zone 4.

[0031] Example 2

[0032] (1) Synthesis of ZIF-8: 7.5 g of zinc nitrate hexahydrate was added to 80 mL of solvent and stirred for 20 min until completely dissolved, designated as solution A. 15.0 g of 2-methylimidazole was added to 100 mL of deionized water and stirred for 20 min until completely dissolved, designated as solution B. Solution B was added to solution A under magnetic stirring. The mixture was then magnetically stirred at 85°C for 6.0 h and allowed to stand for 14 h. The precipitate was collected and dried at 100°C for 14 h to obtain the final product.

[0033] (2) Synthesis of CA@ZIF-8: 8.0 g of sodium alginate was dissolved in 80 mL of deionized water with stirring at 60°C for 6 h to obtain solution A. 10 g of ZIF-8 was dispersed in 80 mL of deionized water with continuous stirring to obtain solution B. Solution B was added to solution A under magnetic stirring to uniformly disperse the solution, obtaining solution C. Solution C was immersed in 600 mL of a 30 g / L calcium chloride aqueous solution and reacted at 60°C for 4 h. Finally, the reaction product was collected by filtration and dried at 100°C for 14 h to obtain CA@ZIF-8.

[0034] (3) Preparation of CA@ZIF-8 / MPP / PP meltblown nonwoven fabric: 4 wt% CA@ZIF-8, 4 wt% MPP, and 92 wt% PP were melt-mixed in a twin-screw extruder and pumped to a spinneret via a metering pump. The mixture was blown out by a blower and laid into a web. The resulting CA@ZIF-8 / MPP / PP flame-retardant and antibacterial meltblown nonwoven fabric was collected and designated as Sample 2. In this step, the screw speed was 20 Hz, and the screw heating temperatures were 222°C in zone 1, 225°C in zone 2, 228°C in zone 3, and 230°C in zone 4.

[0035] Example 3

[0036] (1) Synthesis of ZIF-8: 9.0 g of zinc nitrate hexahydrate was added to 100 mL of solvent and stirred for 20 min until completely dissolved, designated as solution A. 20.0 g of 2-methylimidazole was added to 100 mL of deionized water and stirred for 20 min until completely dissolved, designated as solution B. Solution B was added to solution A under magnetic stirring. The mixture was then magnetically stirred at 85°C for 6.0 h and allowed to stand for 14 h. The precipitate was collected and dried at 100°C for 14 h to obtain the final product.

[0037] (2) Synthesis of CA@ZIF-8: 10.0 g of sodium alginate was dissolved in 100 mL of deionized water with stirring at 60°C for 6 h to obtain solution A. 13 g of ZIF-8 was dispersed in 100 mL of deionized water with continuous stirring to obtain solution B. Solution B was added to solution A under magnetic stirring to uniformly disperse the solution, obtaining solution C. Solution C was immersed in 800 mL of a 30 g / L calcium chloride aqueous solution and reacted at 60°C for 4 h. Finally, the reaction product was collected by filtration and dried at 100°C for 14 h to obtain CA@ZIF-8.

[0038] (3) Preparation of CA@ZIF-8 / MPP / PP meltblown nonwoven fabric: 6 wt% CA@ZIF-8, 2 wt% MPP, and 92 wt% PP were melt-mixed in a twin-screw extruder and pumped to a spinneret via a metering pump. The mixture was blown out by a blower and laid into a web. The resulting CA@ZIF-8 / MPP / PP flame-retardant and antibacterial meltblown nonwoven fabric was collected and designated as Sample 3. In this step, the screw speed was 20 Hz, and the screw heating temperatures were 221°C in zone 1, 224°C in zone 2, 226°C in zone 3, and 230°C in zone 4.

[0039] Example 4

[0040] (1) Synthesis of ZIF-8: 7.5 g of zinc nitrate hexahydrate was added to 80 mL of solvent and stirred for 10 min until completely dissolved (Solution A). 15.0 g of 2-methylimidazole was added to 100 mL of deionized water and stirred for 10 min until completely dissolved (Solution B). Solution B was added to Solution A under magnetic stirring. The mixture was then magnetically stirred at 120°C for 0.5 h and allowed to stand for 6 h. The precipitate was collected and dried at 60°C for 24 h to obtain the product ZIF-8.

[0041] (2) Synthesis of CA@ZIF-8: 8.0 g of sodium alginate was dissolved in 80 mL of deionized water with stirring at 60°C for 6 h to obtain solution A. 10 g of ZIF-8 was dispersed in 80 mL of deionized water with continuous stirring to obtain solution B. Solution B was added to solution A under magnetic stirring to uniformly disperse the solution, obtaining solution C. Solution C was immersed in 600 mL of a 30 g / L calcium chloride aqueous solution and reacted at 25°C for 8 h. Finally, the reaction product was collected by filtration and dried at 60°C for 24 h to obtain CA@ZIF-8.

[0042] (3) Preparation of CA@ZIF-8 / MPP / PP meltblown nonwoven fabric: 4 wt% CA@ZIF-8, 4 wt% MPP, and 92 wt% PP were melt-mixed in a twin-screw extruder and pumped to a spinneret via a metering pump. The mixture was blown out by a blower and laid into a web, which was then collected to obtain a flame-retardant and antibacterial CA@ZIF-8 / MPP / PP meltblown nonwoven fabric. In this step, the screw speed was 15 Hz, and the screw heating temperatures were 190°C in zone 1, 220°C in zone 2, 225°C in zone 3, and 230°C in zone 4.

[0043] Example 5

[0044] (1) Synthesis of ZIF-8: 7.5 g of zinc nitrate hexahydrate was added to 80 mL of solvent and stirred for 30 min until completely dissolved, designated as solution A. 15.0 g of 2-methylimidazole was added to 100 mL of deionized water and stirred for 30 min until completely dissolved, designated as solution B. Solution B was added to solution A under magnetic stirring. The mixture was then magnetically stirred at 20°C for 10 h and allowed to stand for 24 h. The precipitate was collected and dried at 100°C for 12 h to obtain the product, ZIF-8.

[0045] (2) Synthesis of CA@ZIF-8: 8.0 g of sodium alginate was dissolved in 80 mL of deionized water with stirring at 60°C for 6 h to obtain solution A. 10 g of ZIF-8 was dispersed in 80 mL of deionized water with continuous stirring to obtain solution B. Solution B was added to solution A under magnetic stirring to uniformly disperse the solution, obtaining solution C. Solution C was immersed in 600 mL of a 30 g / L calcium chloride aqueous solution and reacted at 100°C for 2 h. Finally, the reaction product was collected by filtration and dried at 100°C for 14 h to obtain CA@ZIF-8.

[0046] (3) Preparation of CA@ZIF-8 / MPP / PP meltblown nonwoven fabric: 4 wt% CA@ZIF-8, 4 wt% MPP, and 92 wt% PP were melt-mixed in a twin-screw extruder and pumped to a spinneret via a metering pump. The mixture was blown out by a blower and laid into a web, which was then collected to obtain a flame-retardant and antibacterial CA@ZIF-8 / MPP / PP meltblown nonwoven fabric. In this step, the screw speed was 50 Hz, and the screw heating temperatures were 222°C in zone 1, 225°C in zone 2, 235°C in zone 3, and 240°C in zone 4.

[0047] The flame retardancy of pure polypropylene (PP) and the MOFs modified polypropylene melt-blown nonwoven fabrics prepared in Examples 1-3 were tested for their flame retardancy. Considering that polypropylene shrinks when heated, it is not convenient to directly test the flame retardancy of the melt-blown fabric. Therefore, the polypropylene composite melt was prepared into a specimen and tested according to the national standards GB / T2046.2-2009 and GB / T2048-2021. The vertical combustion test process is as follows: Figure 1 The flame retardant performance test results are shown in Table 1:

[0048] Table 1

[0049] Components LOI (%) UL94 <![CDATA[pHHR((kW / m 2 )]]> <![CDATA[THR(MJ / m 2 )]]> Pure PP 18.0 none 806.3 89.8 Sample 1 28.2 V-2 467.0 69.2 Sample 2 30.6 V-0 222.6 62.2 Sample 3 29.2 V-0 248.7 64.7

[0050] The data in Table 1 show that the MOFs modified polypropylene melt-blown nonwoven fabric of the present invention has excellent flame retardant properties, and its limiting oxygen index can be as high as 30.6%. Figure 1 、 Figure 2 and Figure 3The MOFs-modified polypropylene meltblown nonwoven fabric of the present invention achieved a V-0 rating in the vertical combustion test (UL 94) using a vertical combustion process. Furthermore, a comparison of the data in Table 1 shows that the MOFs-modified polypropylene meltblown nonwoven fabric of the present invention achieves optimal flame retardancy when both CA@ZIF-8 and MPP content are 4 wt%.

[0051] Similarly, pure polypropylene (PP) was used as a comparison, and the antibacterial properties of pure PP and MOFs modified polypropylene melt-blown non-woven fabrics prepared in Examples 1-3 were tested. The test results are as follows: Figure 2 As shown in Figure 2, it was found that with the increase of CA@ZIF-8 content, the diameter of the inhibition zone of the composite material continued to increase. According to the formula Calculations show that when the CA@ZIF-8 content reaches 4 wt% or above, the antibacterial efficiency can reach more than 99%.

[0052] The above embodiments are intended only to illustrate the technical solutions of the present invention and are not intended to limit the scope of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art will appreciate that the technical solutions of the present invention may be modified or replaced with equivalents without departing from the spirit and scope of the technical solutions of the present invention, and such modifications or equivalents shall be encompassed by the claims of the present invention. Any techniques, shapes, and structures not described in detail herein are well known.

Claims

1. MOFs modified polypropylene melt-blown non-woven fabric, characterized in that: The method comprises the following raw materials: calcium alginate / ZIF-8 1-8 wt%, melamine polyphosphate 0.5-8 wt%, and polypropylene 90-98 wt%. The raw materials for preparing the calcium alginate / ZIF-8 mainly include sodium alginate, ZIF-8, and calcium chloride, and the mass ratio of the sodium alginate, ZIF-8, and calcium chloride is 4-5:5-6.5:9-12; The preparation method of MOFs modified polypropylene melt-blown non-woven fabric comprises the following steps: CA@ZIF-8 was prepared by adding sodium alginate to deionized water and stirring at 25-80°C for 2-6 hours to dissolve to obtain a sodium alginate solution. ZIF-8 was dispersed in deionized water with continuous stirring to obtain a ZIF-8 suspension. The ZIF-8 suspension was added to the sodium alginate solution under magnetic stirring to uniformly disperse the mixture. The obtained mixed solution was immersed in a calcium chloride aqueous solution and reacted at 25-100°C for 2-8 hours. The reaction product was filtered and collected, and dried at 60-100°C for 3-24 hours to obtain CA@ZIF-8. CA@ZIF-8 / MPP / PP melt-blown non-woven fabric was prepared by melt-mixing 1-8 wt% calcium alginate / ZIF-8, 0.5-8 wt% melamine polyphosphate and 90-98 wt% polypropylene in a twin-screw extruder. The mixture was then delivered to a spinneret via a metering pump, blown out by a fan and laid into a net, and the CA@ZIF-8 / MPP / PP flame-retardant and antibacterial melt-blown non-woven fabric was collected.

2. The MOFs modified polypropylene melt-blown nonwoven fabric according to claim 1, characterized in that: The MOFs modified polypropylene melt-blown non-woven fabric comprises the following raw materials: 4 wt% of calcium alginate / ZIF-8, 4 wt% of melamine polyphosphate, and 92 wt% of polypropylene.

3. The MOFs modified polypropylene melt-blown nonwoven fabric according to claim 1, characterized in that: The concentration of the calcium chloride aqueous solution is 30 g / L.

4. The MOFs modified polypropylene melt-blown nonwoven fabric according to claim 1, characterized in that: The preparation method of ZIF-8 is as follows: zinc acetate dihydrate is added to a solvent and stirred for 10 to 30 minutes until it is completely dissolved to obtain a zinc acetate solution; 2-methylimidazole is added to deionized water and stirred for 10 to 30 minutes until it is completely dissolved to obtain a methylimidazole solution; the methylimidazole solution is added to the zinc acetate solution under magnetic stirring; and then the mixture is magnetically stirred at 20 to 120° C. for 0.5 to 10.0 hours, and then allowed to stand for 6 to 24 hours. The precipitate is collected and dried at 60 to 100° C. for 6 to 24 hours to obtain ZIF-8.

5. The MOFs modified polypropylene melt-blown nonwoven fabric according to claim 4, characterized in that: The mass ratio of the zinc acetate dihydrate to 2-methylimidazole is 0.9 to 1:

2.

6. The MOFs modified polypropylene melt-blown nonwoven fabric according to claim 1, characterized in that: The screw speed of the twin-screw extruder is 15-50 Hz, and the screw heating temperature is 190-240°C.

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