Antibacterial and antiviral multifunctional filter screen and preparation method thereof

Abstract

The invention relates to an antibacterial and antiviral multifunctional filter screen and a preparation method thereof, and the preparation method comprises the following steps: S1, dissolving dopamine hydrochloride in a first solvent to obtain a first mixed solution; s2, adding an antibacterial and antiviral agent into the first mixed solution to obtain a second mixed solution; and S3, immersing the polypropylene filter screen in the second mixed solution for surface deposition treatment, and drying to obtain the antibacterial and antiviral multifunctional filter screen, compared with the prior art, dopamine is adopted as a bonding layer and a wrapping layer, dopamine molecules and an antibacterial and antiviral agent are treated to the surface of a PP net through a surface deposition method, a functional agent is wrapped while dopamine forms a polymerization reaction, and a core-shell structure is formed; the adhesive has the effects of adhering, fixing and slowly releasing the functional medicament, so that the problem that the antibacterial and antiviral agent is easy to lose in the prior art is solved.

Description

Technical Field

[0001] This invention relates to the field of filter material technology, specifically to an antibacterial and antiviral multifunctional filter and its preparation method. Background Technology

[0002] With increasing demands for health and environmental protection, the need for fiber materials with antibacterial and antiviral functions is also growing. In air conditioners, filters play a crucial role in physically intercepting dust, microorganisms, and other contaminants from the air. Polypropylene (PP) filters are widely used due to their excellent mechanical properties and durability. However, PP filters have poor moisture absorption and are susceptible to microbial attack, leading to easy degradation, discoloration, and the production of unpleasant odors. Therefore, users are demanding higher antibacterial and antiviral performance from air conditioner filters.

[0003] Currently, some research involves introducing antibacterial and antiviral agents during the spinning process to improve functionality. However, this technology still has some problems, such as poor compatibility between the antibacterial and antiviral agents and the fiber substrate, insufficient antibacterial and antiviral effects, and excessive addition amounts. Other technologies use post-processing methods to introduce antibacterial and antiviral agents onto the fiber surface, but this method suffers from insufficient adhesion between the antibacterial and antiviral agents and the fiber substrate, which is generally based on physical bonding. Furthermore, since air conditioning filters require annual cleaning, their durability is challenged. Summary of the Invention

[0004] The purpose of this invention is to overcome at least one of the defects in the prior art by providing an antibacterial and antiviral multifunctional filter and its preparation method. This invention uses dopamine as both an adhesive and encapsulating layer. Dopamine molecules and antibacterial and antiviral agents are deposited onto the surface of a PP mesh using a surface deposition method. During the polymerization reaction of dopamine, the functional agents are encapsulated, forming a core-shell structure that serves both as an adhesive and a means of fixing and slowly releasing the functional agents, thereby overcoming the problem of easy loss of antibacterial and antiviral agents in the prior art.

[0005] The objective of this invention can be achieved through the following technical solutions:

[0006] One objective of this invention is a method for preparing an antibacterial and antiviral multifunctional filter, characterized by comprising the following steps:

[0007] S1. Dissolve dopamine hydrochloride in the first solvent to obtain the first mixture;

[0008] S2. Add antibacterial and antiviral agents to the first mixture to obtain the second mixture;

[0009] S3. The polypropylene (PP) filter screen is immersed in the second mixture for surface deposition treatment, and then dried to obtain an antibacterial and antiviral multifunctional filter screen.

[0010] The monofilaments in the polypropylene filter screen have a porous structure with a pore size of 1-100 μm.

[0011] Furthermore, the first solvent is a mixture of methanol and buffer solution.

[0012] Furthermore, the volume ratio of the methanol to the buffer solution is (1-3):(1-3).

[0013] Furthermore, the buffer solution is a Tris-HCl buffer solution with a pH of 8-9.

[0014] Furthermore, the active ingredient in the antibacterial and antiviral agent is one or more of zinc ions, silver ions, and copper ions. Specifically, the antibacterial and antiviral agent is zinc oxide (Zinc). One or more of the following: Z3000, silver ions (Silvadur930Flex), and copper ions (cutton1902).

[0015] Furthermore, the surface deposition temperature in S3 is 25-60℃.

[0016] Furthermore, the drying temperature in S3 is 80-130℃, and the drying time is 3-30 minutes.

[0017] Furthermore, the polypropylene filter screen satisfies at least one of the following conditions:

[0018] ①The polypropylene monofilaments in the polypropylene filter screen have a diameter of 0.08-0.20 mm and a roughness of 0.1-10 μm;

[0019] ②The polypropylene filter screen is a plain weave screen, and the warp and weft weave density can be 8-48 filaments per centimeter.

[0020] Furthermore, the preparation method of the polypropylene filter screen is as follows: polypropylene, foaming agent, lubricating masterbatch and anti-aging masterbatch are mixed evenly, spun at 180-280℃, and then woven into a mesh to obtain a polypropylene filter screen.

[0021] The mass ratio of polypropylene, foaming agent, lubricating masterbatch, and anti-aging masterbatch is (91-98):(1-5):(0.5-2):(0.5-2).

[0022] The foaming agent is one or more of azodicarbonamide, azobisisobutyronitrile, p-toluenesulfonamide, etc.; the lubricating masterbatch is polyethylene wax; the effective components of the anti-aging masterbatch are light stabilizer UV944, antioxidant 168 and 1010.

[0023] The second objective of this invention is to provide an antibacterial and antiviral multifunctional filter, which is prepared by the method described above, wherein the surface of the monofilament of the filter has a core-shell structured dopamine coating.

[0024] Compared with the prior art, the present invention has the following advantages:

[0025] (1) This invention uses dopamine as an adhesive layer and a coating layer. Dopamine molecules and antibacterial and antiviral agents are treated onto the surface of PP mesh by surface deposition. While dopamine forms a polymerization reaction, the functional agents are encapsulated to form a core-shell structure, which plays the role of both adhesion and fixation and slow release of functional agents, thereby overcoming the problem of easy loss of antibacterial and antiviral agents in the prior art.

[0026] Because dopamine molecules contain phenolic hydroxyl and amino groups, they possess strong polarity and have a certain affinity for hydrophobic and nonpolar PP filter screens. When the PP filter screen is immersed in a weakly alkaline (pH 8.0-8.5) dopamine aqueous solution, dissolved oxygen oxidizes the dopamine into dopaquinone, which then triggers a complex oxidative self-polymerization reaction, generating a highly adhesive polydopamine film. Furthermore, the high surface roughness of the PP filter screen allows dopamine molecules to penetrate into the micropores and gaps in the filter screen, forming a mechanical anchor after curing, which significantly enhances the physical adhesion.

[0027] (2) This invention introduces a foaming agent during the spinning process of PP mesh to create a certain roughness on the surface of the filament. When dopamine molecules and antibacterial and antiviral agents penetrate into these micropores, the anchoring effect can be increased, and the adhesion between the adhesive and the agent can be improved, thus solving the problem of poor adhesion between antibacterial agents and fiber substrates in the prior art.

[0028] (3) The preparation method of the present invention is simple and feasible, and the process is controllable. Through the self-polymerization reaction of dopamine on the surface of PP filter, a core-shell structure is formed with antibacterial and antiviral agents, thereby making the prepared PP filter have good antibacterial and antiviral properties and long-term stability, effectively solving the problem of insufficient adhesion and easy loss of antibacterial and antiviral agents in the prior art.

[0029] (4) The compound antiviral and antibacterial multifunctional PP mesh prepared by the present invention has excellent antibacterial and antiviral effects, can effectively inhibit the invasion of bacteria and viruses, extend the service life of PP fibers, and does not cause secondary pollution to the living environment. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the preparation process of the antibacterial and antiviral multifunctional filter in this invention. Detailed Implementation

[0031] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are implemented based on the technical solution of the present invention, providing detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0032] Example 1

[0033] This embodiment provides a method for preparing an antibacterial and antiviral multifunctional filter. The specific process is detailed below. Figure 1 Includes the following steps:

[0034] S1: Preparation of Polypropylene (PP) Monofilament: Polypropylene raw material (T30S), PP foaming masterbatch (F-56), lubricating masterbatch (PEW-0319), and anti-aging masterbatch (JHPPFL-03) are mixed evenly at a mass ratio of 97:1:1:1. The mixture is then melt-extruded, cooled, stretched, and set using a spinning machine. The effective components in the foaming masterbatch decompose during heating to produce carbon dioxide, resulting in a microporous structure in the PP monofilament with a pore size of 25-35 μm, a surface roughness of 0.5 μm, and a filament diameter of 0.14 mm. The spinning temperature is 250℃, the cooling temperature is 30℃, the setting temperature is 140℃, the draw ratio is 5.6, and the draw temperature is 95℃.

[0035] S2: Preparation of PP filter screen: The above PP monofilaments are woven into a mesh using a shearing machine. The structure is a plain weave mesh with a weaving density of 24 filaments per centimeter in both the warp and weft directions.

[0036] S3: Preparation of dopamine solution (5 mmol / L): Dopamine hydrochloride is dissolved in a mixture of methanol and buffer solution (CH3OH: buffer solution = 1:1), wherein the buffer solution is prepared using Tris and hydrochloric acid (pH 8.5). The mixture of methanol and buffer solution helps to uniformly disperse dopamine molecules in the solution, maintains the pH stability of the reaction system, and avoids uneven particle size or abnormal morphology of dopamine due to pH fluctuations during polymerization.

[0037] S4: Preparation of a mixed solution of antibacterial and antiviral agents and dopamine: Slowly add 10 L of 6 wt% silver ion solution dropwise to the 10 L of dopamine solution prepared above. The silver ion used is Silvadur 930Flex.

[0038] S5: Preparation of PP-DOPA: Immerse the PP filter screen in the above mixed solution at a temperature of 40°C. Dry the filter screen at 80°C for 3 minutes to obtain a brown PP antibacterial and antiviral filter screen with a core-shell structure and dopamine coating, abbreviated as PPK-DOPA.

[0039] Example 2

[0040] The difference from Example 1 is that in step S4, the antibacterial and antiviral agent used is zinc oxide solution, while everything else remains the same.

[0041] Comparative Example 1

[0042] Comparative Example 1 is basically the same as Example 1, except that no foaming masterbatch is added in the preparation of polypropylene (PP) monofilaments.

[0043] Comparative Example 2

[0044] This comparative example is basically the same as Example 1, except that the mixed solution in this comparative example contains only antibacterial and antiviral agents.

[0045] Comparative Example 3

[0046] This comparative example is basically the same as Example 1, except that the mixed solution in this comparative example contains only dopamine solution.

[0047] Table 1. Performance of the filters prepared in Examples 1-2 and Comparative Examples 1-3

[0048]

[0049] Note: Antibacterial rate test: The bacterial strain was Staphylococcus aureus, and the test standard was GB 21551.2;

[0050] Antiviral rate test: H1N1 influenza virus, test standard is ISO 18184:2019, time is 2 hours.

[0051] Active ingredient content testing: ICP-OES was used.

[0052] As shown in Table 1, in Example 1, dopamine encapsulates silver ions and, through its strong adhesive properties, firmly adheres to the pores and surface of the PP filter screen. Even after soaking the filter screen in water for 1 hour, the silver ion content does not decrease significantly, and the antibacterial and antiviral properties of the filter screen reach 99.99% and above, respectively, before and after soaking in water. After dopamine hydrochloride is dissolved in Tris-HCl buffer, dissolved oxygen oxidizes dopamine to dopaquinone, which then triggers an oxidative self-polymerization reaction to generate a polydopamine film. The polydopamine molecule contains phenolic hydroxyl (-OH) and amino (-NH2) groups. On the one hand, it can bind to silver ions through coordination, encapsulating the silver ions to form a core-shell structure with silver ions as the core and polydopamine as the shell, physically preventing silver ions from directly contacting water. On the other hand, the polar groups of phenolic hydroxyl and amino groups can form weak chemical bonds with the hydrophobic, nonpolar PP filter screen surface, achieving chemical adhesion between polydopamine and PP and preventing coating peeling. PP filter screens are manufactured by adding a foaming agent during spinning to form a monofilament microporous structure. During polymerization, polydopamine penetrates into the micropores and gaps in the filter screen, and after curing, it forms an interlocking mechanical anchor with the PP, meaning it doesn't just adhere to the filter screen surface. This further enhances the bonding force between the polydopamine-silver ion composite layer and the PP. Under this dual effect, even after immersion in water for 1 hour, only a slight loss of silver ions is observed, with a retention rate exceeding 95%. Furthermore, the concentration remains consistently above the threshold for disrupting bacterial cell membranes and inhibiting viral nucleic acid replication, resulting in an antibacterial rate consistently >99.99% and an antiviral rate exceeding 99%.

[0053] Compared to Example 1, in Example 2, after replacing the active ingredient silver with zinc, the antibacterial and antiviral properties of zinc are slightly weaker than those of silver ions. However, due to the presence of dopamine, the water resistance of the filter is still greatly improved, resulting in superior antibacterial properties and slightly inferior antiviral properties compared to Example 1.

[0054] Compared to Example 1, no foaming agent was added during the preparation of the filter in Comparative Example 1. The monofilaments in the resulting filter were ordinary monofilaments with no pores on the surface, resulting in slightly poorer dopamine adhesion than in Example 1. After soaking, the silver ion retention rate was 71.4%, and the antiviral rate decreased to 90%. In Comparative Example 1, the binding of dopamine to PP relied solely on chemical adhesion. Without a foaming agent, the surface of the PP monofilaments was smooth and without pores, preventing polydopamine from penetrating into the interior. It could only form a thin polymer film on the PP surface, and the bonding force was limited to the weak chemical bonds on the surface. When soaked in water, the water flow easily caused the surface polydopamine film to detach locally, leading to the loss of the encapsulated silver ions. The silver ion retention rate in Comparative Example 1 was 71.4%, far lower than the 95.4% in Example 1. Because antiviral performance is more sensitive to silver ion concentration, when the silver ion concentration is below the threshold, the antiviral rate drops from 99.5% to 90%; while antibacterial performance has relatively lower requirements for silver ion concentration, and residual silver ions can still inhibit bacterial growth, so the antibacterial rate is still >99.99%.

[0055] Compared to Example 1, the filter in Comparative Example 2 was only impregnated with antibacterial and antiviral agents. After immersion, the silver ion retention rate was only 4.5%, the antibacterial rate dropped to 24%, and the antiviral rate dropped to 10%. This is because PP is a hydrophobic nonpolar material, while silver ions are polar ions. There is no chemical interaction between the two; they only adhere to the PP surface through weak electrostatic adsorption. When immersed in water, the water flow can easily destroy this physical adsorption, resulting in a large loss of silver ions. In Comparative Example 2, the silver ion retention rate was only 4.5%, and the remaining silver ion concentration was far below the antibacterial and antiviral thresholds. Therefore, the antibacterial rate dropped from >99.99% to 24%, and the antiviral rate dropped from 99.5% to 10%.

[0056] Compared to Example 1, the filter in Comparative Example 3 was only impregnated with dopamine, and the filter never had effective antibacterial or antiviral functions.

[0057] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention in any other way. Any person skilled in the art may make changes or modifications to the above-disclosed technical content to create equivalent embodiments. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A method for preparing an antibacterial and antiviral multifunctional filter, characterized in that, Includes the following steps: S1. Dissolve dopamine hydrochloride in the first solvent to obtain the first mixture; S2. Add antibacterial and antiviral agents to the first mixture to obtain the second mixture; S3. The polypropylene filter screen is immersed in the second mixture for surface deposition treatment, and then dried to obtain an antibacterial and antiviral multifunctional filter screen. The monofilaments in the polypropylene filter screen have a porous structure with a pore size of 1-100 μm.

2. The method for preparing an antibacterial and antiviral multifunctional filter according to claim 1, characterized in that, The first solvent is a mixture of methanol and buffer solution.

3. The method for preparing an antibacterial and antiviral multifunctional filter according to claim 2, characterized in that, The volume ratio of methanol to the buffer solution is (1-3):(1-3).

4. The method for preparing an antibacterial and antiviral multifunctional filter according to claim 2, characterized in that, The buffer solution is a Tris-HCl buffer solution with a pH of 8-9.

5. The method for preparing an antibacterial and antiviral multifunctional filter according to claim 1, characterized in that, The active ingredient in the antibacterial and antiviral agent is one or more of zinc ions, silver ions, and copper ions.

6. The method for preparing an antibacterial and antiviral multifunctional filter according to claim 1, characterized in that, The surface deposition temperature in S3 is 25-60℃.

7. The method for preparing an antibacterial and antiviral multifunctional filter according to claim 1, characterized in that, The drying temperature in S3 is 80-130℃, and the time is 3-30 minutes.

8. The method for preparing an antibacterial and antiviral multifunctional filter according to claim 1, characterized in that, The polypropylene filter screen meets at least one of the following conditions: ①The polypropylene monofilaments in the polypropylene filter screen have a diameter of 0.08-0.20 mm and a roughness of 0.1-10 μm; ②The polypropylene filter screen is a plain weave screen with a warp and weft weave density of 8-48 filaments per centimeter.

9. The method for preparing an antibacterial and antiviral multifunctional filter according to claim 1, characterized in that, The polypropylene filter screen is prepared by mixing polypropylene, foaming agent, lubricating masterbatch and anti-aging masterbatch evenly, spinning at 180-280℃, and then weaving the screen to obtain the polypropylene filter screen. The mass ratio of polypropylene, foaming agent, lubricating masterbatch, and anti-aging masterbatch is (91-98):(1-5):(0.5-2):(0.5-2). The foaming agent includes one or more of azodicarbonamide, azobisisobutyronitrile, and p-toluenesulfonamide. The lubricating masterbatch includes polyethylene wax; The anti-aging masterbatch includes one or more of the light stabilizer UV944 and antioxidants 168 and 1010.

10. A multifunctional filter screen with antibacterial and antiviral properties, characterized in that, It is obtained by the preparation method described in any one of claims 1-9.

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