阅读说明：本技术 一种有机无机杂化多级结构空气过滤防护材料 (Organic-inorganic hybrid air filtration protective material with multilevel structure ) 是由 王栋 夏明� 刘轲 朱美芳 孟哲一 程盼 于 2021-09-28 设计创作，主要内容包括：本发明提供了一种有机无机杂化多级结构空气过滤防护材料,通过将微纳尺寸的无机粒子分散于纳米纤维悬浮液中,经混合均匀后涂覆于多孔无纺布基材表面得到。如此操作,微纳尺寸的粒子与纳米纤维在无纺布表面形成了纳米纤维杂化网络结构,不仅提高了纳米纤维膜的孔隙、孔隙率、比表面积和表面粗糙度,又能赋予空气过滤防护材料杀菌消毒的作用。本发明具有制备方法简单、耗时短的特点,便于大规模制备,具有较高的经济价值,为解决熔喷驻极无纺布和静电纺丝纳米纤维膜在长期使用和存放过程中,驻极电荷和静电荷易受到外界环境如温度和湿度的影响,从而影响了其长期使用的稳定性和安全性问题,提供了一种新的解决方法和思路。(The invention provides an organic-inorganic hybrid air filtration protective material with a multilevel structure, which is obtained by dispersing inorganic particles with micro-nano sizes in a nanofiber suspension, uniformly mixing and coating the mixture on the surface of a porous non-woven fabric substrate. By the operation, the particles with the micro-nano size and the nano fibers form a nano fiber hybrid network structure on the surface of the non-woven fabric, so that the porosity, specific surface area and surface roughness of the nano fiber membrane are improved, and the air filtration protective material has the sterilization and disinfection effects. The invention has the characteristics of simple preparation method and short time consumption, is convenient for large-scale preparation, has higher economic value, and provides a new solution and thinking for solving the problems that the electret charge and the electrostatic charge are easily influenced by the external environment such as temperature and humidity in the long-term use and storage process of the melt-blown electret non-woven fabric and the electrostatic spinning nanofiber membrane, so that the long-term use stability and safety of the melt-blown electret non-woven fabric and the electrostatic spinning nanofiber membrane are influenced.)

1. The organic-inorganic hybrid air filtration protective material with the multilevel structure is characterized by comprising a porous base material and nano fibers and micro-nano particles which are coated and loaded on the surface of the porous base material by a wet method.

2. The organic-inorganic hybrid air filtration protective material with the multilevel structure according to claim 1, wherein the diameter of the nanofiber is 100-800 nm.

3. The organic-inorganic hybrid air filtration/protection material with a multilevel structure according to claim 2, wherein the nanofiber is one or more of an ethylene-vinyl alcohol copolymer nanofiber, a polyester nanofiber, a polyacrylonitrile nanofiber, a polyamide nanofiber, and a polyolefin nanofiber.

4. The organic-inorganic hybrid air filtration protective material with the multilevel structure according to claim 1, wherein the nanofibers and the micro-nano-sized particles are loaded by coating a suspension containing the nanofibers and the micro-nano-sized particles on the surface of the porous substrate by spin coating, spray coating, blade coating or dipping adsorption.

5. The organic-inorganic hybrid multilevel structure air filtration protective material of claim 4, wherein the solvent for preparing the suspension is a mixed solvent of deionized water and isopropanol.

6. The organic-inorganic hybrid multilevel structure air filtration protective material of claim 1, wherein the porous substrate is a nonwoven fabric porous substrate.

7. The organic-inorganic hybrid multilevel structure air filtration protective material according to any one of claims 1 to 6, wherein the micro-nano sized particles are flower-like, sea urchin-like, dendritic, needle-like, honeycomb-like or dumbbell-like micro-nano sized particles.

8. The organic-inorganic hybrid air filtration protective material of claim 7, wherein the micro-nano sized particles include but are not limited to one or more of zinc oxide nanoflowers, silver-doped zinc oxide nanoflowers, gold-doped zinc oxide nanoflowers, and titanium dioxide nanoflowers.

9. The organic-inorganic hybrid air filtration protective material with the multilevel structure according to claim 7, wherein the total loading amount of the nanofibers and the micro-nano-sized particles is 3-40 g/m²Said isThe ratio of the loading amount of the nanofibers to the micro-nano particles is (1-5): 1.

10. The organic-inorganic hybrid air filtration protective material with the multilevel structure according to claim 7, wherein the average diameter of the micro-nano-sized particles is 1-6 μm.

Technical Field

The invention relates to the technical field of filtering materials, in particular to an organic-inorganic hybrid air filtering protective material with a multilevel structure.

Background

The new coronaviruses are highly contagious, mainly through respiratory droplets produced by sneezing, coughing, talking or breathing of infected persons, or aerosol particles formed with particles present in the air. The novel coronavirus can keep infectivity for at least more than 16h in the ultrafine particle aerosol, and poses serious threat to the life health of people.

In recent years, environmental monitoring center has aimed PM₁₀(respirable particles, particles having a diameter of 10 μm or less in the atmosphere) and PM_2.5(particles that can enter the lung, particles in the atmosphere having a diameter of less than or equal to 2.5 microns) are increasingly being detected. PM (particulate matter)₁₀Can be directly inhaled into respiratory tract by human and cause health hazard; PM (particulate matter)_2.5Small grain size, rich toxic and harmful substances, long retention time in the atmosphere and long conveying distance. Therefore, the air filtering material is developed, and the problem that the novel coronavirus infection and haze pollution cause interference on human health is urgently solved.

Air filtration articles such as masks, air filters, gas masks, and the like are increasingly gaining importance in maintaining human green life and physical health. The air filtering material must have the functions of intercepting the solid harmful substances in the air or generating adsorption reaction with the solid harmful substances, and the like, so that the purposes of purifying the air and ensuring the health of human beings can be achieved. The protective material for the mask in the current market is mainly melt-blown electret polypropylene non-woven fabric. The electrostatic action of electret charge is mainly utilized to adsorb ultrafine particles, and the filter has higher filtering efficiency and lower energy consumption. However, static charges and electret charges are easily affected by temperature and humidity in the external environment, and are easily attenuated during long-term storage and use, so that stability and safety of long-term use are difficult to ensure. For example, patent CN 201220687602.5 discloses a multi-layer composite air filter material for step filtration, which realizes interception filtration of particles with different diameters by arranging multiple layers of non-woven fabrics and glass fiber layers, but with the increase of filtration resistance. Patent CN201710330648.9 discloses a microfiber three-dimensional framework/polymer nanofiber composite filter material and a preparation method thereof, wherein a polymer nanofiber pre-crosslinking agent is dispersed in a solvent, then a microfiber non-woven fabric is soaked in a suspension, and the solvent is removed after freeze drying, so that a non-woven material with polymer nanofiber aerogel distributed in a gradient manner among microfiber frameworks is obtained. Although the material has higher filtering efficiency and lower pressure drop, the polymer nano-fiber is loaded on the non-woven fabric through freeze drying and crosslinking, the process is more complex and time-consuming, and the material depends on expensive equipment, is not beneficial to the large-scale production of the air filtering material, and has low economic value.

In view of the above, there is a need to design an improved organic-inorganic hybrid air filtration protective material with a multilevel structure to solve the above problems.

Disclosure of Invention

In order to overcome the defects of the prior art, the invention aims to provide an organic-inorganic hybrid air filtration protective material with a multilevel structure.

In order to achieve the aim, the invention provides an organic-inorganic hybrid air filtration protective material with a multilevel structure, which comprises a porous base material, and nano fibers and micro-nano-sized particles which are coated on the surface of the porous base material by a wet method.

As a further improvement of the invention, the diameter of the nanofiber is 100-800 nm.

As a further improvement of the invention, the nanofiber is one or more of an ethylene-vinyl alcohol copolymer nanofiber, a polyester nanofiber, a polyacrylonitrile nanofiber, a polyurethane nanofiber, a polyamide nanofiber and a polyolefin nanofiber.

As a further improvement of the invention, the nano fibers and the particles with the micro-nano sizes are loaded by coating a suspension containing the nano fibers and the particles with the micro-nano sizes on the surface of the porous substrate through spin coating, spray coating, blade coating or dipping adsorption.

As a further improvement of the invention, the solvent used for preparing the suspension is a mixed solvent of deionized water and isopropanol.

As a further improvement of the present invention, the porous substrate is a nonwoven fabric porous substrate.

As a further improvement of the invention, the micro-nano-sized particles are flower-shaped, sea urchin-shaped, dendritic, needle-shaped, honeycomb-shaped or dumbbell-shaped micro-nano-sized particles.

As a further improvement of the invention, the micro-nano-sized particles include but are not limited to one or more of zinc oxide nanoflower, silver-doped zinc oxide nanoflower, gold-doped zinc oxide nanoflower and titanium dioxide nanoflower.

As a further improvement of the invention, the total load of the nano fibers and the micro-nano particles is 3-40 g/m²And the loading ratio of the nano fibers to the micro-nano particles is (1-5): 1.

As a further improvement of the invention, the average diameter of the micro-nano particles is 1-6 μm.

The invention has the beneficial effects that:

1. according to the organic-inorganic hybrid air filtration protective material with the multilevel structure, the particles with the micro-nano size are added into the nanofiber suspension, so that the dispersibility of the nanofibers can be improved, the problem of accumulation of the nanofibers when the nanofibers are loaded on the surface of a base material is solved, the porosity and the pore diameter of a nanofiber membrane are improved, the filtration efficiency is improved, and the pressure drop is reduced.

2. According to the organic-inorganic hybrid air filtration protective material with the multilevel structure, provided by the invention, the nanofiber hybrid network with the multi-scale structure is formed on the surface of the non-woven fabric by utilizing the micro-nano particles and the nanofibers, so that the porosity can be improved, and the strength of the filter material can be improved. In particular, the non-spherical micro-nano particles with pointed or branched structures and the like are selected, so that the dispersibility of the nano fibers and the richness of the organic-inorganic hybrid multilevel structure can be obviously improved, and the comprehensive performance of the filter material can be improved. The invention has the characteristics of simple preparation method and short time consumption, is convenient for large-scale preparation, has higher economic value, and provides a new solution and thought for solving the problems of the stability and the safety of the melt-blown electret non-woven fabric and the electrostatic spinning nanofiber membrane in long-term use.

3. The organic-inorganic hybrid air filtration protective material with the multilevel structure can select micro-nano particles with an antibacterial function, improves the filtration efficiency, and can endow a filter material with the antibacterial function, so that two functions can be achieved at one time.

Drawings

Fig. 1 is a scanning electron microscope image of zinc oxide nanoflower prepared in example 1.

Fig. 2 is an X-ray diffraction pattern of zinc oxide nanoflower prepared in example 1.

In FIG. 3, a, b, c and d are scanning electron micrographs of the surface of the filter material prepared in comparative example 2 and examples 1 to 3 in this order.

FIG. 4 is a graph showing the relationship between the filtration efficiency and the pressure drop of nanofibers with different grammage loaded on the surface of a non-woven fabric and zinc oxide nanoflowers

FIG. 5 is a graph showing the filtration efficiency and pressure drop for aerosol particles of different particle sizes for filter materials prepared in comparative example 2 and examples 1-4.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in detail below with reference to specific embodiments.

It should be noted that, in order to avoid obscuring the present invention with unnecessary details, only the structures and/or processing steps closely related to the scheme of the present invention are shown in the specific embodiments, and other details not closely related to the present invention are omitted.

In addition, it is also to be noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.

The invention provides an organic-inorganic hybrid air filtration protective material with a multilevel structure, which comprises a porous base material and nano fibers and particles with micro-nano sizes, wherein the nano fibers and the particles with micro-nano sizes are coated on the surface of the porous base material by a wet method. The nanofiber and the particles with the micro-nano sizes are loaded by coating a suspension containing the nanofiber and the particles with the micro-nano sizes on the surface of the porous base material through spin coating, spray coating, blade coating or dipping adsorption.

Experiments show that the nano-sized particles are added into the nano-fiber suspension, so that the dispersibility of the nano-fibers can be improved, the problem of accumulation of the nano-fibers when the nano-fibers are loaded on the surface of a base material is solved, the porosity and the pore diameter of a nano-fiber membrane are improved, the filtration efficiency is improved, and the pressure drop is reduced. The organic-inorganic hybrid air filtration protective material provided by the invention has the highest filtration efficiency of 96.29% + -0.40 for 0.3 mu m particles, 99.08% + -0.10 for 0.5 mu m particles, 99.93% + -0.01 for 1.0 mu m particles, 99.90% + -0.06 for 2.0 mu m particles, 100% for 5.0 mu m particles and 100% for 10.0 mu m particles.

Specifically, the diameter of the nanofiber is preferably 400-800 nm.

The nano-fiber is selected from one or more of ethylene-vinyl alcohol copolymer nano-fiber, polyester nano-fiber, polyacrylonitrile nano-fiber, polyurethane nano-fiber, polyamide nano-fiber and polyolefin nano-fiber.

The solvent of the suspension is a mixed solvent of deionized water and isopropanol, and the volume ratio is about 1 (1-4).

The porous substrate is preferably a non-woven fabric porous substrate, the nano fibers can form a strong load effect with the non-woven fabric, and the nano fibers can be dispersedly adsorbed in pores of the non-woven fabric to form uniform and small pores, so that the filtering efficiency of small-particle-size particles is improved, and the pressure drop is prevented from being overlarge. In some embodiments, after the suspension is coated on the surface of the non-woven fabric by a wet method, hot pressing or cold pressing at a certain temperature can be performed, or other substances with hot-melt cohesiveness are added into the suspension, so as to improve the load fastness of the nanofibers and the particles with micro-nano sizes on the surface of the non-woven fabric.

The micro-nano-sized particles are preferably non-spherical micro-nano particles, for example, having a pointed or branched structure. The micro-nano sized particles are preferably flower-like, sea urchin-like, dendritic, needle-like, honeycomb-like or dumbbell-like micro-nano sized particles. The micro-nano particles are more beneficial to improving the dispersion and porosity of the nano fibers, and pores (such as pores formed among flower pieces of the nanoflower) are formed among dendritic structures, so that the porosity of the filter material is improved. The particles with the micro-nano size and the nano fibers form a nano fiber hybrid network with a multi-scale structure on the surface of the non-woven fabric, so that the porosity, the specific surface area and the surface roughness of the nano fiber membrane are improved, the filtering efficiency of the filtering material is improved, and the air filtering resistance is reduced.

The micro-nano-sized particles are preferably particles having an antibacterial function, for example, one or more selected from the group consisting of zinc oxide nanoflowers, silver-doped zinc oxide nanoflowers, gold-doped zinc oxide nanoflowers, and titanium dioxide nanoflowers. By selecting the micro-nano particles, the filtering efficiency is improved, and meanwhile, the antibacterial function can be given to the filtering material, so that two functions can be achieved at one time.

The total load capacity of the nanofiber and the micro-nano-sized particles is 3-40 g/m²The ratio of the loading amounts of the nanofibers and the micro-nano particles is (1-5): 1. The average diameter of the micro-nano particles is 1-6 mum。

Examples 1 to 3 and comparative examples 1 to 2

The organic-inorganic hybrid air filtration protective material with the multilevel structure provided by the embodiments 1-3 and the comparative examples 1-2 is prepared by loading zinc oxide nano-rice flower and ethylene-vinyl alcohol copolymer nano-fiber on a non-woven fabric substrate, and specifically comprises the following steps:

s1, mixing 0.035mol.l^-1Zn (CH) of₃OO)₂·2H₂O and 0.45mol.l^-1Reacting the solution with NaOH at 70 ℃ for 24 hours to obtain the zinc oxide nano-flowers. As shown in fig. 1 and 2, the successful preparation of zinc oxide nanoflower was demonstrated by the present invention.

S2, preparing pure nanofiber suspension by using 2g of nanofibers, 60g of isopropanol and 40g of deionized water, dividing 60ml of nanofiber suspension into 4 parts, and placing 15ml of each part in a 50ml beaker. Then 4 flat-bottom centrifuge tubes are prepared, 5ml of deionized water is added into each centrifuge tube, and 0.1 g, 0.3g and 0.5g of zinc oxide are added into three centrifuge tubes to prepare zinc oxide suspension liquid with uniform dispersion. And then the deionized water or the suspension in the centrifuge tube is respectively poured into a beaker filled with the nanofiber suspension, and the mixture is uniformly mixed by magnetic stirring to prepare a new mixed suspension.

And coating the composite suspension on the surface of the polypropylene non-woven fabric by a wet method to obtain the nanofiber hybrid air filtration protective material with a multi-scale structure.

Specific coating parameters are shown in table 1, wherein the grammage refers to the total loaded grammage of the nanofibers and zinc oxide nanoflowers. As shown in fig. 3, it can be seen that the surface of the non-woven fabric in embodiments 1 to 3 of the present invention successfully supports the nanofibers and the zinc oxide nanoflower hybrid network with the multi-scale structure, and the supported amount gradually increases, both of the supported amount and the supported amount are attached to the surface of the non-woven fabric to form uniform pores, which is helpful for improving the filtration efficiency. In this embodiment, the zinc oxide nanoflowers and the ethylene-vinyl alcohol copolymer nanofiber composite suspension are selected, and the large-sized zinc oxide nanoflowers have a skeleton effect, so that the nanofibers are dispersed and wound on the surface of the zinc oxide, and the pores, porosity, specific surface area and surface roughness of the nanofiber membrane are improved.

TABLE 1 preparation parameters and filtration Performance test results for examples 1-3 and comparative examples 1-2

As can be seen from table 1, the nonwoven fabric without supporting nanofibers has a low filtration efficiency for particles having a small particle size, particularly, a filtration efficiency of only 29.76% for 0.3 μm particles, although the pressure drop is small. The non-woven fabric only loading the nano fibers obviously improves the filtering efficiency of small-particle-size particles, but the pressure drop is obviously increased. After the zinc oxide nano-flowers are loaded, the pressure drop is reduced, and the filtration efficiency is improved to an unapproved degree, wherein the filtration efficiency on 0.3 mu m particles can reach 96.29 percent to the maximum, and the filtration efficiency on 0.5 mu m particles can reach 99.08 percent to the maximum, and the invention can obviously improve the filtration performance on air by adding a proper amount of zinc oxide nano-flowers into the nano-fiber suspension. When the content of the zinc oxide nano-flowers is too high, the filtration efficiency is increased, but the pressure drop is also increased, so that the addition of a proper amount of the zinc oxide nano-flowers is beneficial to improving the comprehensive performance.

Examples 4 to 6

Compared with the air filtration protective material in the embodiment 2, the organic-inorganic hybrid multi-level structure provided in embodiments 4 to 6 is different in that the micro-nano particles are shown in table 2, and the others are substantially the same as those in embodiment 1, and are not described herein again.

Table 2 preparation conditions and filtration performance test results of examples 4 to 6

It can be seen from table 2 that the addition of other types of micro-nano particles with dendritic structures, such as nano-flowers or sea urchins, to the nanofiber suspension all facilitates the uniform dispersion and deposition of nanofibers on the surface of the nonwoven fabric, thereby improving the porosity and pore size of the nanofiber membrane and improving the strength of the filter material. Therefore, the preparation method realizes the preparation of the high-function filter material through simple organic-inorganic hybridization and has higher economic value.

In conclusion, according to the organic-inorganic hybrid air filtration protective material with the multilevel structure, provided by the invention, the dispersibility of the nanofibers can be improved by adding the micro-nano-sized particles into the nanofiber suspension, so that the problem of accumulation of the nanofibers when the nanofibers are loaded on the surface of the base material is solved, the porosity and the pore diameter of the nanofiber membrane and the roughness of the surface are improved, the filtration efficiency is further improved, and the pressure drop is reduced. The nanofiber hybrid network with the multi-scale structure is formed on the surface of the non-woven fabric by utilizing the particles with the micro-nano size and the nanofibers, so that the porosity, the specific surface area and the surface roughness can be improved, the filtering efficiency of aerosol particles is improved, and the air resistance is reduced. The preparation method provided by the invention is short in time consumption, convenient for large-scale preparation and high in economic value, and provides a new solution and thought for solving the problems of stability and safety of the melt-blown electret non-woven fabric and the electrostatic spinning nanofiber membrane in long-term use.

Although the present invention has been described in detail with reference to the preferred embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the spirit and scope of the invention.