Technical Field

[0001] The present invention relates to a polypropylene non-woven fabric and a preparation method of the polypropylene non-woven fabric.

Background Art

[0002] Non-woven fabrics are moisture-proof, breathable, flexible, lightweight, flame- retardant, non-toxic, tasteless, inexpensive, and recyclable. At present, the demand for non-woven fabrics in the medical and public health fields is gradually increasing, and higher requirements are placed on the antibacterial and antiviral properties of non-woven fabrics.

[0003] At present, the methods of treating non-woven fabrics for antibacterial and antiviral functions are mainly divided into two categories: one is to load antibacterial and antiviral agents into spinning fibrils, and the other one is to make the prepared non-woven fabrics adsorb or graft the antibacterial and antiviral agents on the surface of the non-woven fabric through the subsequent chemical modifications or physical impregnation processes.

[0004] Antibacterial and antiviral agents can be mainly divided into three categories: natural agents, organically synthetic agents, and inorganic agents according to their different components. The natural antibacterial and antiviral agents have poor heat resistance and short efficacy, and have not achieved large-scale production. The organically synthesized small- molecule antibacterial and antiviral agents have poor thermal stability and low processing temperature (less than 200 degrees), and their applications are greatly limited. Among the inorganic antibacterial and antiviral agents, nano-silver or silver-loaded materials have the highest antiviral performance. However, the preparation process of nano-silver is complicated and the stability is poor. In addition, the cost of silver-carrying materials is high, and its application in non- woven fabrics is difficult to promote.

[0005] In view of the foregoing issues, it is necessary to design an antiviral nonwoven fabric with strong antiviral properties and low production costs.

Summary of the Invention [0006] One object of the present invention is to provide an antiviral polypropylene non- woven fabric with strong antiviral performance, low costs and a simple process.

[0007] The above object of the present application is achieved by the following technical solutions: an antiviral polypropylene non-woven fabric is prepared from a polypropylene antibacterial master batch and polypropylene as raw materials, wherein the polypropylene antibacterial master batch is loaded with a silver-cerium zeolite material.

[0008] A total amount of the silver-cerium zeolite material in the polypropylene antibacterial master batch is 20-30wt%.

[0009] A a mass ratio of the polypropylene antibacterial master batch to polypropylene is

3-5% : 95-97%.

[0010] Another object of the present application is to provide a method for preparing the antiviral polypropylene non-woven fabric.

[0011] Specifically, the method for preparing the antiviral polypropylene non-woven fabric comprises the following steps:

[0012] (1) Preparation of the silver-cerium zeolite material: taking a NaY-type zeolite loaded with silver ions and cerium ions to obtain the silver-cerium zeolite material.

[0013] (2) Preparation of the polypropylene antibacterial master batch: taking polypropylene and heating it to melting, adding the silver-cerium zeolite material, stirring, blending and granulating to obtain the polypropylene antibacterial master batch.

[0014] (3) Preparation of the antiviral polypropylene non-woven fabric: after uniformly mixing the polypropylene antibacterial master batch and polypropylene, melting, filtering, spinning into a web, and finally ironing by a pressure roller to make the antiviral polypropylene non-woven fabric.

[0015] In some embodiments of the present application, in step (1), the NaY-type zeolite is roasted at 280-300 degrees for 3-5 hours, dispersed in a mixed solution of silver nitrate and cerium nitrate, stirred in the dark for 1.5-2.5 hours, washed and dried, calcined, and then cooled and ground, so as to obtain the silver-cerium zeolite material.

[0016] The roasting temperature is 400-500 degrees, and the roasting time is 1-2 hours.

[0017] In the mixed solution of silver nitrate and cerium nitrate, the concentration of silver nitrate is 20-30g/L, and the concentration of cerium nitrate is 25-35g/L.

[0018] The present invention has the following beneficial effects: [0019] 1. The antiviral polypropylene (PP) non-woven fabric provided by the invention adopts silver-cerium zeolite material as its antiviral agent. It is prepared in a process firstly using a PP powder to make a polypropylene antibacterial master batch, which is then mixed with polypropylene to prepare the product by means of spinning. In the pre sent invention, the antibacterial properties of silver ions and rare earth ions are combined, which are further combined with the excellent adsorption properties of zeolite so as to synergistically improve the antiviral properties of non-woven fabrics.

[0020] With regard to the free silver ions that can be released from the non-woven fabric provided by the present invention, according to the Fenton reaction mechanism, free silver ions can interact with proteins, nucleic acid and other biological macromolecules by binding to specific sites to form complexes. In the presence of dissolved oxygen and water in a solution, this complex can undergo a continuous cyclic redox reaction. A large number of hydroxyl radicals can be generated near biological macromolecules. Hydroxyl free radicals have strong oxidizing properties, and thus have a strong destructive effect on the structures of biological macromolecules. This inactivates microorganisms such as viruses. The silver ions can chemically bond with the oxygen atom on the phosphate group in the viral nucleotide, generate a dipole moment on the phosphate group, and induce the production of cyclic phosphate. In this case, the phosphodiester bond connecting two adjacent nucleotides is broken, so that the nucleic acid chain of the virus is broken, which affects the replication of the genetic information of the virus. For DNA viruses, the silver ions can form purine/silver/pyrimidine chemical bonds in the DNA double helix structure, which can replace the hydrogen bonds between adjacent purines and pyrimidines to form a more stable helix structure. This hinders the unwinding of DNA, making it difficult for viruses to reproduce effectively. If the protein on the surface of the virus contains a sulfhydryl group, the silver ions can irreversibly bind to the sulfhydryl group, resulting in protein denaturation and inactivation.

[0021] The non-woven fabric provided by the invention can also release rare earth cerium ions, which can interact with cell walls, cell membranes, enzymes, proteins, DNAs and RNAs to inhibit the growth of microorganisms. The rare earth ions have a similar radius to a calcium ion, and their complexing ability with oxygen, sulfur, and nitrogen is greater than that of the calcium ion. Thus, they can be excellent antagonists of calcium ions. The addition of rare earth ions changes the permeability of the microbial cell membrane and also inhibits the growth of microorganisms. [0022] The composite use of silver ions and rare earth ions is employed in the present invention. When light containing ultraviolet rays is irradiated to the non-woven fabric, due to the existence of valence electrons in the outer layer, electrons and holes are generated. Most of the electrons are captured by the outer valence band of rare earth elements, and the generated electron- hole concentration is much higher than that without the introduction of rare earth. At the same time, some electrons transitioning to the valence electron band of rare earth elements are also easily captured by silver atoms to form silver negative ions. Due to the above two types of activations, the antiviral properties of the non-woven fabric can be further strengthened.

[0023] 2. The present invention adopts the NaY type zeolite as a carrier. Through an ion exchange method, the double loading of silver ions and cerium ions can be carried out with it. The prepared silver-cerium zeolite material can be used as an active antiviral element. The microporous channel structure of the zeolite can be used to effectively immobilize metal ions and combine them with silver ions and cerium ions. In addition, by means of a blending melt spinning process, the surface and interior of the non-woven fibers are modified and loaded. Thus, the prepared non- woven fabric has an efficient and durable antiviral function.

Description of the Embodiments

[0024] The present invention will be described in detail below in conjunction with the embodiment. It should be pointed out that the following examples are intended to facilitate the understanding of the present invention, but do not have any limiting effect on it.

[0025] Example 1

[0026] (1) Preparation of a silver-cerium zeolite material: the NaY zeolite of 200 meshes are roasted at 280 degrees for 5 hours, dispersed in a mixed solution of 25 g/L silver nitrate and 30 g/L cerium nitrate (solution pH=5), kept away from light and stirred for 2 hours, and then washed, dries at 450 degrees, and then roasted for 1 hour, then cooled and ground to obtain a silver- cerium zeolite material of 1250 meshes.

[0027] (2) Preparation of a polypropylene antibacterial master batch: polypropylene is heated to 200 degrees, the polypropylene is melted, the silver-cerium zeolite material is then added into the melt in an addition amount of 25wt% of the mass of the polypropylene, that is, the loading is 25wt%; next, stirring, blending and granulating are performed to obtain the polypropylene antibacterial master batch. [0028] (3) Preparation of an antiviral polypropylene non-woven fabric: the polypropylene antibacterial master batch and polypropylene are uniformly mixed in a mass ratio of 5% : 95%, the mixture is then extruded and melted to obtain a melt; the melt is filtered to remove impurities, spanned to form a web, and finally ironed by a high temperature roller to obtain an antiviral PP non-woven fabric.

[0029] The prepared non-woven fabric has been tested for its antiviral activity by the

Guangdong Microbiological Analysis and Testing Center according to ISO 18184:2019(E). The antiviral activity rate for influenza A H3N2 is 98.3%, and the antiviral activity rate for human coronavirus is 97.1%. Thus, it is proved that the prepared non-woven fabric has good antiviral properties, and can meet the demands for non-woven fabrics in the medical and public health fields. [0030] Table 1 : Results of anti-viral PP non-woven fabric against influenza A virus H3N2

[0031]

[0032] Table 2: Results of antiviral PP non-woven fabric against human coronavirus

HCoV-229E

[0033]

[0034] Example 2

[0035] Its difference from example 1 is as follows: the mass ratio of polypropylene antibacterial master batch to polypropylene is 3% : 97%. The antiviral effect of the non-woven fabric is comparable to that of Example 1.

[0036] Example 3

[0037] Its difference from example 1 is as follows: in the mixed solution of silver nitrate and cerium nitrate, the concentration of silver nitrate is 25.5 g/L, and the concentration of cerium nitrate is 30.5 g/L of cerium nitrate. The antiviral effect of the non-woven fabric is comparable to that of Example 1.

[0038] Example 4

[0039] Its difference from example 1 is as follows: in the mixed solution of silver nitrate and cerium nitrate, the concentration of silver nitrate is 26 g/L, and the concentration of cerium nitrate is 31 g/L of cerium nitrate. The antiviral effect of the non-woven fabric is comparable to that of Example 1. [0040] Example 5

[0041] (1) Preparation of a silver-cerium zeolite material: the NaY zeolite of 200 meshes are roasted at 300 degrees for 3 hours, dispersed in a mixed solution of 25 g/L silver nitrate and 30 g/L cerium nitrate (solution pH=5), kept away from light and stirred for 2 hours, and then washed, dries at 450 degrees, and then roasted for 1 hour, then cooled and ground to obtain a silver- cerium zeolite material of 12050 meshes.

[0042] (2) Preparation of a polypropylene antibacterial master batch: polypropylene is heated to 220 degrees, the polypropylene is melted, the silver-cerium zeolite material is then added into the melt in an addition amount of 20wt% of the mass of the polypropylene, that is, the loading is 20wt%; next, stirring, blending and granulating are performed to obtain the polypropylene antibacterial master batch.

[0043] (3) Preparation of an antiviral polypropylene non-woven fabric: the polypropylene antibacterial master batch and polypropylene are uniformly mixed in a mass ratio of 5% : 95%, the mixture is then extruded and melted to obtain a melt; the melt is filtered to remove impurities, spanned to form a web, and finally ironed by a high temperature roller to obtain an antiviral PP non-woven fabric.

[0044] The antiviral effect of the non-woven fabric is comparable to that of Example 1.

[0045] Example 6

[0046] Its difference from example 6 is as follows: the mass ratio of the polypropylene antibacterial master batch to polypropylene is 4% : 96%. The antiviral effect of the non-woven fabric is comparable to that of Example 1.

[0047] Example 7

[0048] Its difference from example 6 is as follows: in the mixed solution of silver nitrate and cerium nitrate, the concentration of silver nitrate is 24.5 g/L, and the concentration of cerium nitrate is 29.5 g/L of cerium nitrate. The antiviral effect of the non-woven fabric is comparable to that of Example 1.

[0049] Example 8

[0050] Its difference from example 6 is as follows: in the mixed solution of silver nitrate and cerium nitrate, the concentration of silver nitrate is 24 g/L, and the concentration of cerium nitrate is 29 g/L of cerium nitrate. The antiviral effect of the non-woven fabric is comparable to that of Example 1. [0051] Example 9

[0052] (1) Preparation of a silver-cerium zeolite material: the NaY zeolite of 200 meshes are roasted at 280 degrees for 3 hours, dispersed in a mixed solution of 25 g/L silver nitrate and 30 g/L cerium nitrate (solution pH=5), kept away from light and stirred for 2 hours, and then washed, dries at 450 degrees, and then roasted for 1 hour, then cooled and ground to obtain a silver- cerium zeolite material of 12050 meshes.

[0053] (2) Preparation of a polypropylene antibacterial master batch: polypropylene is heated to 210 degrees, the polypropylene is melted, the silver-cerium zeolite material is then added into the melt in an addition amount of 30wt% of the mass of the polypropylene, that is, the loading is 30wt%; next, stirring, blending and granulating are performed to obtain the polypropylene antibacterial master batch.

[0054] (3) Preparation of an antiviral polypropylene non-woven fabric: the polypropylene antibacterial master batch and polypropylene are uniformly mixed in a mass ratio of 5% : 95%, the mixture is then extruded and melted to obtain a melt; the melt is filtered to remove impurities, spanned to form a web, and finally ironed by a high temperature roller to obtain an antiviral PP non-woven fabric.

[0055] The antiviral effect of the non-woven fabric is comparable to that of Example 1.

[0056] Example 10

[0057] Its difference from example 9 is as follows: in the mixed solution of silver nitrate and cerium nitrate, the concentration of silver nitrate is 24.5 g/L, and the concentration of cerium nitrate is 29.5 g/L of cerium nitrate. The antiviral effect of the non-woven fabric is comparable to that of Example 1.

[0058] Example 11

[0059] Its difference from example 9 is as follows: in the mixed solution of silver nitrate and cerium nitrate, the concentration of silver nitrate is 24 g/L, and the concentration of cerium nitrate is 29 g/L of cerium nitrate. The antiviral effect of the non-woven fabric is comparable to that of Example 1.

[0060] The above examples are only used to illustrate the technical solutions of the present invention but not to limit the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, a person skilled in the art should understand that the technical solutions of the present invention may be modified or equivalently replaced without departing from the principles and scopes of the technical solutions of the present invention.