Preparation method of antibacterial and antiviral master batch

Abstract

The invention relates to a preparation method of an antibacterial and antiviral master batch, and belongs to the technical field of antibacterial master batches. The preparation method of the antibacterial and antiviral master batch comprises the following steps: mixing the nano-silver particles and the dispersing agent, adding the modified zinc oxide, uniformly stirring, adding the plastic master batch base material, mixing, and carrying out melt extrusion and granulation in a double-screw extruder to obtain the antibacterial and antiviral master batch. The antibacterial plastic master batch can directly generate an antibacterial layer on the surface of a product, so that the antibacterial and bactericidal effects are effectively exerted. Meanwhile, by means of matching of different antibacterial agents and particle size adjustment, the sterilization efficiency of the antibacterial plastic master batch is greatly improved.

Description

Technical Field

[0001] The invention belongs to the technical field of antibacterial masterbatch and relates to a method for preparing antibacterial and antiviral masterbatch. Background Art

[0002] With advancements in the plastics industry and improvements in people's living standards, items like telephones, bathtubs, toilets, toys, interior decoration materials, refrigerators, food packaging, plastic containers, and public plastic products are highly susceptible to contamination and bacterial growth, and can even grow mold in dark areas. This drive for hygiene and odor control has driven the rapid development of antimicrobial masterbatches and antimicrobial plastic products. Antimicrobial masterbatches are concentrates made by evenly dispersing multiple antimicrobial ingredients in a matrix resin. By mixing the antimicrobial masterbatch with the appropriate resin particles in a specific ratio and then processing the plastic or fiber using different molding methods, plastic parts, products, and antimicrobial fibers with antimicrobial (bactericidal and antibacterial) properties can be obtained.

[0003] Current antibacterial masterbatches usually add antibacterial agents during the preparation of plastic masterbatches. However, this preparation process causes the antibacterial agent to be wrapped by the raw materials and cannot fully exert its effect. In addition, improper selection of the antibacterial agent results in unsatisfactory antibacterial effects. Summary of the Invention

[0004] The present invention aims to provide a method for preparing an antibacterial and antiviral masterbatch. This antibacterial plastic masterbatch can directly form an antibacterial layer on the surface of the product, effectively exerting its antibacterial and bactericidal effects. Furthermore, by combining different antimicrobial agents and adjusting the particle size, the antibacterial efficacy of the antimicrobial plastic masterbatch is significantly enhanced.

[0005] The purpose of the present invention can be achieved through the following technical solutions:

[0006] A method for preparing an antibacterial and antiviral masterbatch comprises the following steps:

[0007] Step 1: mixing the nano silver particles and the dispersant, adding the modified zinc oxide and stirring evenly to obtain a mixture;

[0008] Step 2: Add the plastic masterbatch base material to the mixture and mix, then melt-extrude through a twin-screw extruder and granulate to obtain the product.

[0009] As a preferred technical solution of the present invention, in step 2, the mixing is performed at 120-140°C for 5-8 minutes, and the melt extrusion temperature is 160-180°C in zone 1, 190-200°C in zone 2, 210-220°C in zone 3, 220-240°C in zone 4, 250-280°C in zone 5, and 260-280°C in zone 6.

[0010] As a preferred technical scheme of the present application, the antibacterial and antiviral master batch comprises the following components in parts by weight: plastic master batch 40-60 parts, nano-silver particles 15-21 parts, modified zinc oxide 6-9 parts and dispersant 4-6 parts.

[0011] As a preferred technical scheme of the present application, the zinc oxide has photocatalytic activity and can release zinc ions to destroy the structure of microorganisms and generate hydroxyl radicals to oxidize and decompose microbial proteins. After modification, functional groups are introduced on the surface to improve the compatibility and antibacterial stability of the plastic matrix. In addition, the nano-silver and the modified zinc oxide synergistically exhibit antibacterial effect, and the dispersant ensures uniform dispersion of the components, ultimately realizing the antibacterial and antiviral function of the master batch.

[0012] The preparation method of the modified zinc oxide comprises the following steps:

[0013] S1, uniformly mix zinc oxide, anhydrous ethanol and silane coupling agent, heat and stir, centrifuge, dry the centrifugal precipitate to obtain silane-modified zinc oxide;

[0014] S2, in an inert atmosphere, add the silane-modified zinc oxide into DMF, add modified salicylaldehyde and initiator, constant temperature stirring, centrifuge, wash the centrifugal precipitate, vacuum drying, to obtain intermediate;

[0015] S3, disperse the intermediate into anhydrous ethanol, add deionized water, cysteine and potassium hydroxide, heat and stir, centrifuge, wash the centrifugal precipitate, vacuum drying, to obtain modified zinc oxide.

[0016] As a preferred technical scheme of the present application, in step S1, the mass ratio of the zinc oxide, anhydrous ethanol and silane coupling agent is 15-20:260-300:5-7.

[0017] As a preferred technical scheme of the present application, in step S1, the heat and stirring treatment is stirring at a temperature of 55-62℃ for 8-10h, the temperature rise accelerates the reaction equilibrium and promotes the hydrolysis and condensation reaction of silane, the centrifugation is at a speed of 1500-1800r / min for 10-15min to separate the unreacted silane, and the drying is at a temperature of 80℃ for 6-8h, and the silane coupling agent is vinyltrimethoxysilane.

[0018] As a preferred technical scheme of the present application, in step S2, the mass ratio of the silane-modified zinc oxide, DMF, modified salicylaldehyde and initiator is 8-10:240-260:3.2-3.6:0.10-0.12, the DMF is N,N-dimethylformamide, and the initiator is ammonium persulfate.

[0019] As a preferred technical scheme of the present application, in step S2, the ammonium persulfate initiates the radical polymerization of the vinyl group on the surface of the zinc oxide and the double bond of the modified salicylaldehyde, so as to realize the grafting of the modified salicylaldehyde, wherein the constant temperature stirring treatment is stirring at 60-65℃ for 4-5h, the centrifugation is at a speed of 2000-2300r / min for 5-8min, the washing is washing with deionized water for 3 times, and the vacuum drying is at 60℃ for 8-10h.

[0020] As a preferred technical scheme of the present application, in step S3, the amino group of the cysteine reacts with the aldehyde group on the surface of the intermediate to introduce a functional group containing a mercapto group, wherein the heating stirring is stirring at 60-65℃ for 4-5h, the centrifugation is at a speed of 2000-2400r / min for 5-8min, the washing is washing with deionized water until neutral, and the vacuum drying is at 80℃ for 10-12h.

[0021] As a preferred technical scheme of the present application, in step S3, the mass ratio of the intermediate, anhydrous ethanol, deionized water, cysteine and potassium hydroxide is 50-55:120-140:20-30:2-4:8-9, preferably, the cysteine is L-cysteine.

[0022] As a preferred technical scheme of the present application, the potassium hydroxide can provide an alkaline environment, promote the deprotonation of the amino group, enhance its nucleophilicity, and accelerate the reaction with the aldehyde group, and it can also simultaneously improve the solubility of the cysteine in the ethanol / water mixed system.

[0023] As a preferred technical scheme of the present application, the preparation of the modified salicylaldehyde comprises the following steps:

[0024] Under an inert atmosphere, the methyl acryloyl chloride and dichloromethane are mixed, then the salicylaldehyde solution is slowly added and heated and stirred, and after purification, the modified salicylaldehyde is obtained.

[0025] As a preferred technical scheme of the present application, in the preparation of the modified salicylaldehyde, the inert atmosphere is a nitrogen atmosphere, the heating stirring is stirring at 35℃ for 5-6h, the amount ratio of the methyl acryloyl chloride and dichloromethane is 2.5-2.8g:10-15mL, and the salicylaldehyde solution is composed of salicylaldehyde, pyridine and dichloromethane in an amount ratio of 3.6-4.0g:1.9-2.1g:50-60mL.

[0026] The present application has the following beneficial effects:

[0027] The antimicrobial plastic masterbatch produced by this invention can directly form an antimicrobial layer on the product surface, effectively exerting its antimicrobial and bactericidal effects. Furthermore, by combining different antimicrobial agents and adjusting the particle size, the bactericidal efficacy of the antimicrobial plastic masterbatch is significantly enhanced.

[0028] Figures in the specification

[0029] Figure 1 This is the FTIR spectrum of the silane-modified zinc oxide in Example 3;

[0030] Figure 2 This is the FTIR spectrum of the modified hydrotalcite in Example 3. Product a is silane-modified zinc oxide. DETAILED DESCRIPTION

[0031] In order to further illustrate the technical means and effects adopted by the present invention to achieve the predetermined purpose of the invention, the specific implementation methods, structures, features and effects of the present invention are described in detail below in combination with the embodiments.

[0032] The plastic masterbatch used in the examples and comparative examples was polypropylene, model S1003, purchased from Shanghai Secco Petrochemical Co., Ltd., the dispersant was dispersant YY-5023, and the nano-silver powder with a particle size of 20 nm and the zinc oxide with a particle size of 20 nm were both purchased from Beijing Zhongke Yannuo.

[0033] Example 1

[0034] The antibacterial and antiviral masterbatch comprises the following components by weight: 40 parts of plastic masterbatch, 15 parts of nanosilver particles, 6 parts of modified zinc oxide and 4 parts of dispersant;

[0035] The preparation method of the modified zinc oxide comprises the following steps:

[0036] S1. Mix zinc oxide, anhydrous ethanol and a silane coupling agent uniformly, stir at 55°C for 10 hours, centrifuge at 1500 rpm for 15 minutes, and dry the centrifugal precipitate at 80°C for 8 hours to obtain silane-modified zinc oxide;

[0037] The mass ratio of zinc oxide, anhydrous ethanol and silane coupling agent is 15:260:5, and the silane coupling agent is vinyltrimethoxysilane;

[0038] S2. In a nitrogen atmosphere, silane-modified zinc oxide was added to DMF, and modified salicylaldehyde and ammonium persulfate were added and mixed. The mixture was stirred at 60°C for 5 h, and centrifuged at 2000 rpm for 8 min. The centrifugal precipitate was washed three times with deionized water, and dried at 60°C for 10 h to obtain an intermediate.

[0039] The mass ratio of the silane-modified zinc oxide, DMF, modified salicylaldehyde and ammonium persulfate is 8:240:3.2:0.10;

[0040] S3. Disperse the intermediate in anhydrous ethanol, add deionized water, cysteine ​​and potassium hydroxide, and stir at 60°C for 5 hours. After completion, centrifuge at 2000 rpm for 8 minutes, take the centrifugal precipitate and wash it with deionized water until it is neutral to obtain modified zinc oxide;

[0041] The mass ratio of the intermediate, anhydrous ethanol, deionized water, cysteine ​​and potassium hydroxide is 50:120:20:2:8.

[0042] The preparation of the modified salicylaldehyde comprises the following steps:

[0043] Under a nitrogen atmosphere, methacryloyl chloride and dichloromethane were mixed, and salicylaldehyde solution was slowly added and stirred at 35°C for 6 hours. The solvent dichloromethane was evaporated off, and the residue was dissolved in ethyl acetate. The mixture was washed three times with deionized water and saturated sodium bicarbonate aqueous solution, and anhydrous magnesium sulfate (15% by weight of the organic phase) was added for dehydration for 20 minutes. The filtrate was dehydrated and filtered to obtain a crude product. The solvent ethyl acetate was evaporated off to obtain a crude product. The crude product was recrystallized from tetrahydrofuran to obtain modified salicylaldehyde.

[0044] The amount ratio of methacryloyl chloride and dichloromethane is 2.5 g:10 mL, the salicylaldehyde solution is composed of salicylaldehyde, pyridine and dichloromethane in a ratio of 3.6 g:1.9 g:50 mL, the mass ratio of the residue and ethyl acetate is 1:6, and the deionized water and saturated sodium bicarbonate aqueous solution are both 10 times the mass of the residue.

[0045] A method for preparing an antibacterial and antiviral masterbatch comprises the following steps:

[0046] Step 1: mixing the nano silver particles and the dispersant, adding the modified zinc oxide and stirring evenly to obtain a mixture;

[0047] Step 2: Add the plastic masterbatch substrate to the mixture and mix at 120°C for 8 minutes. Then, melt-extrude through a twin-screw extruder at 160°C in zone 1, 190°C in zone 2, 210°C in zone 3, 220°C in zone 4, 250°C in zone 5, and 260°C in zone 6, and granulate to obtain the antibacterial and antiviral masterbatch.

[0048] Example 2

[0049] The antibacterial and antiviral masterbatch comprises the following components by weight: 50 parts of plastic masterbatch, 18 parts of nanosilver particles, 8 parts of modified zinc oxide and 5 parts of dispersant;

[0050] The preparation method of the modified zinc oxide comprises the following steps:

[0051] S1, zinc oxide, absolute ethanol and silane coupling agent are mixed uniformly, stirred at 58℃ for 9h, centrifuged at 1650r / min for 12min, the centrifugal precipitate is dried at 80℃ for 7h, and silane modified zinc oxide is obtained;

[0052] The mass ratio of the zinc oxide, absolute ethanol and silane coupling agent is 18:280:6, and the silane coupling agent is vinyl trimethoxysilane.

[0053] S2, the silane modified zinc oxide is added to DMF under nitrogen atmosphere, modified salicylaldehyde and ammonium persulfate are added, stirred at 62℃ for 4.5h, centrifuged at 2150r / min for 6min, the centrifugal precipitate is washed with deionized water for 3 times, and dried at 60℃ for 9h, and an intermediate is obtained.

[0054] The mass ratio of the silane modified zinc oxide, DMF, modified salicylaldehyde and ammonium persulfate is 9:250:3.4:0.11.

[0055] S3, the intermediate is dispersed into absolute ethanol, deionized water, cysteine and potassium hydroxide are added, stirred at 62℃ for 4.5h, after completion, centrifuged at 2200r / min for 6min, the centrifugal precipitate is washed with deionized water until neutral, and modified zinc oxide is obtained.

[0056] The mass ratio of the intermediate, absolute ethanol, deionized water, cysteine and potassium hydroxide is 52:130:25:3:8.5.

[0057] The preparation of the modified salicylaldehyde comprises the following steps:

[0058] Under nitrogen atmosphere, methacryloyl chloride and dichloromethane are mixed, then salicylaldehyde solution is slowly added, stirred at 35℃ for 5.5h, dichloromethane is removed by rotary evaporation, the residue is dissolved in ethyl acetate, washed with deionized water and saturated sodium bicarbonate aqueous solution for 3 times, 15% anhydrous magnesium sulfate is added to the organic phase, dehydrated for 20min, filtered, the filtrate is obtained by removing ethyl acetate by rotary evaporation, and the modified salicylaldehyde is obtained by recrystallization of the crude product in tetrahydrofuran.

[0059] The amount ratio of the methacryloyl chloride and dichloromethane is 2.6g:12mL, the salicylaldehyde solution is composed of salicylaldehyde, pyridine and dichloromethane with the amount ratio of 3.8g:2g:55mL, the mass ratio of the residue and ethyl acetate is 1:6, and the deionized water and saturated sodium bicarbonate aqueous solution are both 10 times of the residue.

[0060] A method for preparing an antibacterial and antiviral master batch comprises the following steps:

[0061] Step 1: mixing the nano silver particles and the dispersant, adding the modified zinc oxide and stirring evenly to obtain a mixture;

[0062] Step 2: Add the plastic masterbatch base material to the mixture and mix at 130°C for 6 minutes. Then, melt-extrude through a twin-screw extruder at 170°C in zone 1, 195°C in zone 2, 215°C in zone 3, 230°C in zone 4, 265°C in zone 5, and 270°C in zone 6, and granulate to obtain the antibacterial and antiviral masterbatch.

[0063] Example 3

[0064] The antibacterial and antiviral masterbatch comprises the following components by weight: 60 parts of plastic masterbatch, 21 parts of nanosilver particles, 9 parts of modified zinc oxide and 6 parts of dispersant;

[0065] The preparation method of the modified zinc oxide comprises the following steps:

[0066] S1. Mix zinc oxide, anhydrous ethanol and a silane coupling agent uniformly, stir at 62°C for 8 hours, centrifuge at 1800 rpm for 10 minutes, and dry the centrifugal precipitate at 80°C for 6 hours to obtain silane-modified zinc oxide;

[0067] The mass ratio of zinc oxide, anhydrous ethanol and silane coupling agent is 20:300:7, and the silane coupling agent is vinyl trimethoxysilane; Figure 1 It can be seen that the zinc oxide modified by silane coupling agent (vinyl trimethoxysilane) has a peak at 1083 cm -1 , proving that the grafting was successful.

[0068] S2. In a nitrogen atmosphere, silane-modified zinc oxide was added to DMF, and modified salicylaldehyde and ammonium persulfate were added and mixed. The mixture was stirred at 65°C for 4 h, and centrifuged at 2300 rpm for 5 min. The centrifugal precipitate was washed three times with deionized water, and dried at 60°C for 8 h to obtain an intermediate.

[0069] The mass ratio of the silane-modified zinc oxide, DMF, modified salicylaldehyde and ammonium persulfate is 10:260:3.6:0.12;

[0070] S3. Disperse the intermediate in anhydrous ethanol, add deionized water, cysteine ​​and potassium hydroxide, and stir at 65°C for 4 hours. After completion, centrifuge at 2400 rpm for 5 minutes, take the centrifugal precipitate and wash it with deionized water until it is neutral to obtain modified zinc oxide;

[0071] The mass ratio of the intermediate, anhydrous ethanol, deionized water, cysteine ​​and potassium hydroxide is 55:140:30:4:9;

[0072] wherein, from Figure 2 It can be seen that the modified salicylaldehyde appears C=C double bond at 1661 cm -1 , and after the reaction of the modified salicylaldehyde with the modified zinc oxide, the C=C is consumed, the peak intensity decreases, a new aldehyde group (C=O) is formed at 1715 cm -1 , finally the aldehyde group reacts with the amino group of cysteine, the C=O is consumed, the peak intensity decreases, and a C=N bond is formed at 1626 cm -1 , which proves that the amino group reacts with the aldehyde group to form a Schiff base, that is, the modified zinc oxide is successfully synthesized.

[0073] The preparation of the modified salicylaldehyde comprises the following steps:

[0074] Under a nitrogen atmosphere, the methacryloyl chloride and dichloromethane are mixed, then the salicylaldehyde solution is slowly added, stirred at 35℃ for 5h, the solvent dichloromethane is removed by rotary evaporation, the residue is dissolved in ethyl acetate, washed with deionized water and saturated sodium bicarbonate aqueous solution three times in turn, dehydrated with anhydrous magnesium sulfate in an amount of 15% of the mass of the organic phase for 20min, filtered after dehydration, and the filtrate is obtained, then the solvent ethyl acetate is removed by rotary evaporation to obtain the crude product, which is recrystallized in tetrahydrofuran to obtain the modified salicylaldehyde.

[0075] wherein, from Figure 2 It can be seen that the modified salicylaldehyde appears C=C double bond at 1661 cm -1 , the amount ratio of the methacryloyl chloride and dichloromethane is 2.8g:15mL, the salicylaldehyde solution is composed of salicylaldehyde, pyridine and dichloromethane with an amount ratio of 4.0g:2.1g:60mL, the mass ratio of the residue and ethyl acetate is 1:6, and the deionized water and saturated sodium bicarbonate aqueous solution are both 10 times the mass of the residue.

[0076] A method for preparing an antibacterial and antiviral master batch comprises the following steps:

[0077] Step one, mix the nano-silver particles and the dispersant, add the modified zinc oxide and stir uniformly to obtain a mixture;

[0078] Step two, add the plastic master batch substrate to the mixture, mix at 140℃ for 5min, then melt and extrude in a twin-screw extruder with a first zone at 180℃, a second zone at 200℃, a third zone at 220℃, a fourth zone at 240℃, a fifth zone at 280℃ and a sixth zone at 280℃, and then granulate to obtain the antibacterial and antiviral master batch.

[0079] Comparative Example 1

[0080] Comparative Example 1 is different from Example 3 in that the nano-silver particles are used instead of the modified zinc oxide, and the rest are the same.

[0081] Comparative Example 2

[0082] Comparative Example 2 differs from Example 3 in that the modified salicylaldehyde is replaced with an equivalent amount of salicylaldehyde, and the preparation method of the modified zinc oxide comprises the following steps:

[0083] S1, uniformly mix zinc oxide, anhydrous ethanol and silane coupling agent, stir at a temperature of 62°C for 8h, centrifuge at a speed of 1800r / min for 10min, take the centrifugal precipitate to dry at a temperature of 80°C for 6h, to obtain silane modified zinc oxide;

[0084] S2, disperse the silane modified zinc oxide into anhydrous ethanol in a nitrogen atmosphere, add salicylaldehyde and mix, add deionized water, cysteine and potassium hydroxide, stir at a temperature of 65°C for 4h, after completion, centrifuge at a speed of 2400r / min for 5min, take the centrifugal precipitate to wash with deionized water until neutral, to obtain modified zinc oxide;

[0085] The rest are consistent.

[0086] Comparative Example 3

[0087] Comparative Example 3 differs from Example 3 in that the silane coupling agent KH560 is used instead of vinyltrimethoxysilane, and the preparation method of the modified zinc oxide comprises the following steps:

[0088] S1, uniformly mix zinc oxide, anhydrous ethanol and silane coupling agent KH560, stir at a temperature of 62°C for 8h, centrifuge at a speed of 1800r / min for 10min, take the centrifugal precipitate to dry at a temperature of 80°C for 6h, to obtain silane modified zinc oxide;

[0089] S2, disperse the silane modified zinc oxide into anhydrous ethanol in a nitrogen atmosphere, add modified salicylaldehyde and mix, add deionized water, cysteine and potassium hydroxide, stir at a temperature of 65°C for 4h, after completion, centrifuge at a speed of 2400r / min for 5min, take the centrifugal precipitate to wash with deionized water until neutral, to obtain modified zinc oxide;

[0090] The rest are consistent.

[0091] Comparative Example 4

[0092] Comparative Example 4 differs from Example 3 in that zinc oxide is used instead of modified zinc oxide, and the rest are consistent.

[0093] Comparative Example 5

[0094] Comparative Example 5 differs from Example 3 in that serine is used instead of cysteine, and the rest are consistent.

[0095] Comparative Example 6

[0096] Compared with Example 3, Comparative Example 6 is different in that cysteine ​​is not used, and the rest are the same.

[0097] The antibacterial masterbatches prepared in Examples 1-3 and Comparative Examples 1-6 were subjected to the following performance tests, and the test results are shown in Table 1.

[0098] Antibacterial performance test: according to GB / T31402-2015;

[0099] Table 1

[0100]

[0101]

[0102] From the test results in Table 1, it can be seen that compared with Comparative Examples 1-6, the antibacterial masterbatch prepared in Examples 1-3 has excellent antibacterial properties.

[0103] The present invention forms a covalent bond between the silanol group generated by the hydrolysis of vinyltrimethoxysilane and the hydroxyl group on the surface of zinc oxide. The vinyl group at the other end can interact with the organic chain segment of the polymer in the masterbatch to significantly improve the uniformity of the dispersion of zinc oxide in the masterbatch. The improved dispersibility can make the antibacterial site of zinc oxide more easily contact with bacteria, while avoiding the problem of zinc oxide agglomeration, and indirectly enhancing the overall antibacterial property of the antibacterial masterbatch. By modifying salicylaldehyde, salicylaldehyde itself has antibacterial activity, destroying cell membrane integrity, or inhibiting the activity of bacterial respiratory chain enzymes, blocking energy metabolism. The modified salicylaldehyde contains a carbon-carbon double bond, which can be introduced into the surface of zinc oxide through chemical bonding with the vinyl group of the silane coupling agent. It can serve as a new antibacterial site, enhance the inherent antibacterial property of the modified zinc oxide, and reduce shedding during the melt extrusion process by strengthening the binding force between zinc oxide and the organic matrix, thereby ensuring the long-term effectiveness of the antibacterial component. The invention forms a strong coordination bond between the thiol group of cysteine ​​and the nanosilver, thereby stabilizing the nanosilver particles, inhibiting their agglomeration during melt extrusion or storage, and maintaining the dispersibility of the nanosilver, thereby ensuring their long-term antibacterial effect.

[0104] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been disclosed as a preferred embodiment as above, it is not intended to limit the present invention. Any person skilled in the art can make some changes or modifications to equivalent embodiments using the technical contents disclosed above without departing from the scope of the technical solution of the present invention. However, any indirect modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A method for preparing an antibacterial and antiviral masterbatch, characterized in that: The preparation method comprises the following steps: Step 1: mixing the nano silver particles and the dispersant, adding the modified zinc oxide and stirring evenly to obtain a mixture; Step 2: Add the plastic masterbatch base material to the mixture and mix, then melt-extrude through a twin-screw extruder to form pellets; The preparation method of the modified zinc oxide comprises the following steps: S1. Evenly mix zinc oxide, anhydrous ethanol and a silane coupling agent, heat and stir, centrifuge, and dry the centrifugal precipitate to obtain silane-modified zinc oxide; S2. In an inert atmosphere, silane-modified zinc oxide is added to DMF, and modified salicylaldehyde and an initiator are added and mixed. The mixture is stirred at a constant temperature and centrifuged. The centrifuged precipitate is washed and vacuum-dried to obtain an intermediate. S3. Disperse the intermediate in anhydrous ethanol, add deionized water, cysteine ​​and potassium hydroxide, heat and stir, centrifuge, take the centrifugal precipitate, wash, and vacuum dry to obtain modified zinc oxide.

2. The method for preparing an antibacterial and antiviral masterbatch according to claim 1, characterized in that: The antibacterial and antiviral masterbatch comprises the following components in parts by weight: 40-60 parts of plastic masterbatch, 15-21 parts of nano silver particles, 6-9 parts of modified zinc oxide and 4-6 parts of dispersant.

3. The method for preparing an antibacterial and antiviral masterbatch according to claim 1, wherein: In step 2, the mixing is performed at 120-140°C for 5-8 minutes, and the melt extrusion temperature is 160-180°C in zone 1, 190-200°C in zone 2, 210-220°C in zone 3, 220-240°C in zone 4, 250-280°C in zone 5, and 260-280°C in zone 6.

4. The method for preparing an antibacterial and antiviral masterbatch according to claim 1, wherein: In step S1, the mass ratio of zinc oxide, anhydrous ethanol and silane coupling agent is 15-20:260-300:5-7, the heating and stirring treatment is stirring at a temperature of 55-62°C for 8-10 hours, the centrifugation is centrifugation at a speed of 1500-1800 r / min for 10-15 minutes, the drying is drying at a temperature of 80°C for 6-8 hours, and the silane coupling agent is vinyltrimethoxysilane.

5. The method for preparing an antibacterial and antiviral masterbatch according to claim 1, wherein: In step S2, the mass ratio of the silane-modified zinc oxide, DMF, modified salicylaldehyde and initiator is 8-10:240-260:3.2-3.6:0.10-0.

12.

6. The method for preparing an antibacterial and antiviral masterbatch according to claim 1, characterized in that: In step S2, the initiator is ammonium persulfate, the constant temperature stirring treatment is stirring at 60-65°C for 4-5 hours, the centrifugation is centrifugation at 2000-2300 r / min for 5-8 minutes, the washing is washing with deionized water 3 times, and the vacuum drying is drying at 60°C for 8-10 hours.

7. The method for preparing an antibacterial and antiviral masterbatch according to claim 1, characterized in that: In step S3, the heating and stirring is stirring at 60-65°C for 4-5 hours, the centrifugation is centrifuging at 2000-2400 r / min for 5-8 minutes, the washing is washing with deionized water until neutral, and the vacuum drying is drying at 80°C for 10-12 hours.

8. The method for preparing an antibacterial and antiviral masterbatch according to claim 1, characterized in that: In step S3, the mass ratio of the intermediate, anhydrous ethanol, deionized water, cysteine ​​and potassium hydroxide is 50-55:120-140:20-30:2-4:8-9.

9. The method for preparing an antibacterial and antiviral masterbatch according to claim 1, characterized in that: The preparation of the modified salicylaldehyde comprises the following steps: Under an inert atmosphere, methacryloyl chloride and dichloromethane are mixed, and then salicylaldehyde solution is slowly added thereto, heated and stirred, and modified salicylaldehyde is obtained after purification.

10. The method for preparing an antibacterial and antiviral masterbatch according to claim 9, characterized in that: In the preparation of modified salicylaldehyde, the heating and stirring is stirring at 35°C for 5-6 hours, the usage ratio of methacryloyl chloride and dichloromethane is 2.5-2.8g:10-15mL, and the salicylaldehyde solution is composed of salicylaldehyde, pyridine and dichloromethane in a usage ratio of 3.6-4.0g:1.9-2.1g:50-60mL.

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