A silver ion polymer for mildew prevention and sterilization and its preparation method

Abstract

This invention belongs to the field of fine chemical technology, specifically relating to a silver ion polymer for mildew prevention and sterilization and its preparation method. The silver ion polymer for mildew prevention and sterilization comprises a hydrophilic unsaturated monomer, a hydrophobic unsaturated monomer, and silver ions; the hydrophilic unsaturated monomer and the hydrophobic unsaturated monomer form a random copolymer; the silver ions are bonded to the random copolymer via ionic bonds or chelation. The silver ion polymer of this invention exhibits significant antibacterial effects, does not precipitate or discolor after long-term storage, has low preparation cost, and is completely miscible with water or organic solvent systems, thus enabling its application in a wide range of mildew prevention and sterilization applications.

Description

Technical Field

[0001] This invention belongs to the field of fine chemical technology, specifically relating to a silver ion polymer for mildew prevention and sterilization and its preparation method. Background Technology

[0002] Silver ions are a widely used contact-type broad-spectrum antifungal and antibacterial substance. When silver ions come into contact with microorganisms such as bacteria and fungi, they can penetrate the cell membrane and enter the cell, disrupting its protein structure and interfering with the microorganism's electron transport system, respiratory system, and substance transport system, leading to cell death due to loss of reproductive capacity. Compared with general organic bactericides, its significant characteristics are: 1) Long-lasting effect: As long as silver ions are present and the surface is kept clean, the antifungal and bactericidal effect of silver ions remains effective as long as they can come into contact with bacteria; 2) Broad spectrum: Studies have reported that silver ions have bactericidal effects on about 650 kinds of bacteria, especially against Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Aspergillus niger, and Candida albicans, with a bactericidal rate of over 99%; 3) Low toxicity: Literature reports that trace amounts of silver ions have no harm to humans and animals; 4) High efficiency: When the silver ion content in the system reaches 0.3 ppm or higher, it has a good bactericidal effect.

[0003] Silver ions have many advantages as inorganic antibacterial agents, but their chemical properties are active, and they are easily transformed into brown silver oxide or reduced to black elemental silver by ultraviolet light catalysis. This not only affects the external quality of the product, but also its antibacterial properties.

[0004] The current development of silver-based antibacterial agents mainly includes three aspects: nano-metallic silver, silver-loaded antibacterial materials (including inorganic and organic types), and the combination of silver with photocatalytically active inorganic substances.

[0005] Nano-sized silver and its compounds are ideal raw materials for manufacturing antibacterial fibers (especially microfibers). The preparation techniques for nano-silver mainly include: physical methods (photoquantum reduction, laser ionization, high-voltage magnetron sputtering, sonochemical methods) and chemical methods (silver ammonia ion reduction, electrochemical reduction, reverse micelle method). A typical example of the combination of silver ions (silver metal) with photocatalytically active materials is the use of nano-titanium dioxide. This combination includes mixed use, generally using a silver-loaded antibacterial material or silver material as the core, with an outer coating or deposition of a photocatalytically active material. Both of these silver-based antibacterial agents are relatively expensive and have limitations in their applicable scenarios.

[0006] Silver-loaded antibacterial materials are broadly classified into inorganic and organic categories. Carrier-based silver antibacterial materials are among the most widely used inorganic antibacterial materials on the market. Carrier materials include zeolite, zirconium phosphate, silica gel, glass, hydroxyapatite, tobermorite, montmorillonite, palygorskite, sepiolite, fluorapatite, coral reef stone, and acrylonitrile-based carbon fibers—all inorganic materials with high specific surface area and high ion exchange capacity. The mechanism of action involves silver ions gradually dissolving from the carrier and reacting with sulfur- and ammonia-containing functional groups such as -SH and -NH₂ in bacterial and fungal cells. This reaction inhibits protein synthesis and energy sources, and disrupts the activity of enzymes in the cell membrane or protoplasm, thereby exerting antibacterial activity. They are favored by researchers due to their safety (low toxicity, non-irritating, non-carcinogenic, non-teratogenic), good sustained-release properties, excellent durability, broad-spectrum antibacterial activity, good heat resistance, and ease of processing. This series of antibacterial agents is currently the most widely used type in China. However, some problems exist in its use, such as the instability of silver ions causing discoloration in antibacterial agents, poor dispersibility in solvents, and the high cost of silver-based antibacterial agents. Furthermore, they are difficult to adhere effectively to surfaces, easily lost, leading to decreased bactericidal performance and poor antifungal and anti-mold effects. Additionally, because inorganic substances are mostly powdery and have high density, they are difficult to disperse effectively in water or organic solutions, thus limiting their use in many situations.

[0007] Organic antibacterial agents mainly involve introducing silver ions into polymers such as polypropylene grafted with sulfonated styrene, polypropylene grafted with acrylic acid, chitosan, and PET surface grafted with acrylamide or itaconic acid, thereby acquiring certain antibacterial activity. However, these antibacterial agents also have drawbacks, including the inability to achieve simultaneous dispersion in both aqueous and organic solvents, and the difficulty in achieving complete miscibility with solvents, leading to problems such as precipitation and discoloration. Summary of the Invention

[0008] The purpose of this invention is to address the aforementioned problems in the prior art by providing a silver ion polymer and its preparation method that exhibits significant antibacterial effects, does not precipitate or change color over long-term storage, has low preparation costs, is completely miscible with water or organic solvent systems, and can be used for mildew prevention and sterilization in a wide range of applications.

[0009] In a first aspect, the present invention provides a silver ion polymer for mildew prevention and sterilization, comprising a hydrophilic unsaturated monomer, a hydrophobic unsaturated monomer, and silver ions; wherein the hydrophilic unsaturated monomer and the hydrophobic unsaturated monomer form a random copolymer; and the silver ions are combined with the random copolymer by means of ionic bonds or chelation.

[0010] The silver ion polymer for mildew prevention and sterilization described in this invention is a clear, transparent, colorless or pale yellow solution. It is obtained by mixing a random copolymer solution formed by dissolving a random copolymer in a solvent with a silver ion solution, and then an ion exchange reaction occurs in the system. The silver ions are fixed to the long polymer chain by ionic bonds or chelation. It has good stability and does not produce any precipitates.

[0011] The effective bactericidal component of the silver ion polymer for mildew prevention and sterilization described in this invention is silver ions rather than elemental silver or silver oxide. Therefore, it does not have the problems of biosafety and reduced specific surface area caused by precipitation and particle aggregation that often occur with nano-silver. Compared with nano-silver, it is safer, has a higher concentration of silver ions per unit area, and has a higher bactericidal efficiency.

[0012] Furthermore, the molar ratio of hydrophilic unsaturated monomers to hydrophobic unsaturated monomers in the random copolymer is 99:1 to 1:99;

[0013] When the molar ratio of hydrophilic unsaturated monomer to hydrophobic unsaturated monomer is 99:1-50:50, the random copolymer is soluble in an aqueous solution with a pH of 6-8 to form a transparent solution.

[0014] When the molar ratio of hydrophilic unsaturated monomer to hydrophobic unsaturated monomer is 49:51-1:99, the random copolymer is soluble in organic solvents to form a transparent solution.

[0015] Further, the hydrophilic unsaturated monomer is at least one selected from sodium allyl sulfonate, sodium methacrylate sulfonate, 1-vinyl-2-pyrrolidone, 2-vinyl-4,6-diaminotriazine, maleic anhydride, methacrylic acid, acrylic acid, N-(1-hydroxy-2,2-dimethoxyethyl)-2-acrylamide, and acrylamide. The molar content of the sulfonic acid monomer accounts for 0-50% of the total hydrophilic unsaturated monomers, the molar content of the carboxyl monomer accounts for 5-99% of the total hydrophilic unsaturated monomers, the molar content of the amide monomer accounts for 0-25% of the total hydrophilic unsaturated monomers, and the molar content of the amino monomer accounts for 0-20% of the total hydrophilic unsaturated monomers.

[0016] Furthermore, the hydrophobic unsaturated monomer is at least one of styrene, α-methylstyrene, methyl methacrylate, butyl acrylate, and isooctyl acrylate.

[0017] Furthermore, the silver ion content in the silver ion polymer is 0.1-5000 ppm.

[0018] Further, the organic solvent is at least one selected from dioxane, ethyl acetate, dimethyl carbonate, diethyl carbonate, N,N-dimethylformamide, and tetrahydrofuran.

[0019] A second aspect of the present invention provides a method for preparing a silver ion polymer for antifungal and antibacterial purposes. The method involves first synthesizing a random copolymer of a hydrophilic unsaturated monomer and a hydrophobic unsaturated monomer containing functional groups on the main chain using solution polymerization. Then, the polymer is reacted with silver ions to fix the silver ions onto the polymer chain via ionic bonds or chelation, resulting in a high-performance silver ion polymer for antifungal and antibacterial purposes. Specifically, the method includes the following steps:

[0020] (1) Preparation of random copolymer: The hydrophilic unsaturated monomer and the hydrophobic unsaturated monomer are mixed and stirred until the mixture is transparent to obtain a monomer mixture; the solvent, initiator and monomer mixture are mixed and heated to react. After the reaction is completed, the mixture is dried to a solid powder, washed and dried to obtain a random copolymer;

[0021] (2) Preparation of random copolymer solution: Dissolve the random copolymer obtained in step (1) in an aqueous solution or organic solvent with a pH value of 6-8, and stir until transparent to obtain random copolymer solution;

[0022] (3) Preparation of silver ion solution: Dissolve silver nitrate in deionized water and stir until transparent to obtain silver ion solution;

[0023] (4) Under stirring conditions, silver ion solution is added dropwise to random copolymer solution and stirred to react to obtain the silver ion polymer used for anti-mildew and antibacterial purposes.

[0024] Further, in step (1), the mass ratio of the hydrophilic unsaturated monomer, the hydrophobic unsaturated monomer, the solvent, and the initiator is 0.9-87.1:1-120.9:205-280:1.8-2.4; the solvent is at least one of dioxane, dimethyl carbonate, deionized water, and dimethylformamide; and the initiator is at least one of potassium persulfate, ammonium persulfate, benzoyl peroxide, and azobisisobutyronitrile.

[0025] First, the solvent and initiator are mixed and heated. When the temperature reaches 55°C, the monomer mixture is added, and the temperature is further heated to 80±1°C. The mixture is kept at this temperature for 2 hours, and then heated to 90±1°C. The mixture is kept at this temperature for 1 hour, and then the reaction is stopped. The reaction solution is dried to a solid powder using a spray dryer, washed with a 5% NaOH aqueous solution, and then dried in an oven at 120°C for 2 hours to obtain the random copolymer.

[0026] Further, in step (2), the organic solvent is at least one of dioxane, ethyl acetate, dimethyl carbonate, diethyl carbonate, N,N-dimethylformamide, and tetrahydrofuran; and the random copolymer solution has a mass percentage concentration of 1%-5% for the random copolymer.

[0027] Furthermore, in step (3), the mass percentage concentration of silver nitrate in the silver ion solution is 1%-5%.

[0028] The beneficial effects of this invention are as follows:

[0029] (1) The silver ion polymer for mildew prevention and sterilization described in this invention fixes silver ions with excellent bactericidal effects onto a long polymer chain composed of hydrophilic and hydrophobic monomers through ionic bonds or chelation. This allows silver to exist stably in ionic form for a long time and form a clear and transparent solution, effectively preventing silver ions from being easily oxidized to silver oxide or reduced to elemental silver during storage, thus avoiding aggregation and significantly reducing the specific surface area of ​​silver, leading to reduced sterilization efficiency or blackening. Therefore, at the same silver ion content, the sterilization efficiency of silver can be greatly improved, resulting in a better sterilization effect. In addition, the hydrophobic segments on the polymer chain facilitate the uniform spreading and adhesion of the silver ion polymer to the surface of objects, allowing silver ions to adhere stably to the surface of objects for a long time, effectively improving the long-lasting bactericidal performance of the silver ion polymer.

[0030] (2) The silver ion polymer for mildew prevention and sterilization described in this invention is characterized by its ease of use, clear and transparent appearance, good stability, and long-lasting broad-spectrum bactericidal effect. Spraying or applying it to the surface of various materials can effectively prevent them from becoming moldy and deteriorating. Tests have shown that objects treated with the silver ion polymer of this invention, even after being left for 6 months, still exhibit a bactericidal and antibacterial rate of over 99% against Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Aspergillus niger, and Candida albicans.

[0031] (3) The silver ion polymer for mildew prevention and sterilization described in this invention can be widely used in mildew prevention and sterilization of leather, textiles, clothing products, papermaking, footwear and sock products and other fields, and has broad application prospects. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be described in detail below. Obviously, the described embodiments are merely some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other implementation methods obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0033] This invention employs a solution method to prepare a polymer containing both hydrophilic and hydrophobic unsaturated monomers in its main chain. This polymer is then reacted with a silver ion solution, whereby the silver ions are immobilized on the polymer chain via ionic bonds or chelation, resulting in a high-performance silver ion polymer for antifungal and antibacterial purposes. The specific process conditions of this invention are further illustrated below with reference to examples. Unless otherwise stated, the polymer composition in the examples is calculated as a molar percentage, and the solution preparation is calculated as a mass percentage.

[0034] Example 1

[0035] A silver ion polymer for mildew prevention and sterilization includes a hydrophilic unsaturated monomer, a hydrophobic unsaturated monomer, and silver ions; the hydrophilic unsaturated monomer and the hydrophobic unsaturated monomer form a random copolymer; the silver ions are combined with the random copolymer by ionic bonds or chelation.

[0036] The hydrophilic unsaturated monomer is composed of the following raw materials: 0.13 mol methacrylic acid, 0.02 mol 1-vinyl-2-pyrrolidone, and 0.05 mol sodium allyl sulfonate; the hydrophobic unsaturated monomer is composed of the following raw materials: 0.2 mol styrene, 0.2 mol methyl methacrylate, and 0.3 mol butyl acrylate. The total molar ratio of the hydrophilic to the hydrophobic unsaturated monomer is 20:70.

[0037] The preparation method of the silver ion polymer for mildew prevention and sterilization described in this embodiment includes the following steps:

[0038] (1) Preparation of random copolymers: At room temperature, 11.2 g of methacrylic acid, 2.2 g of 1-vinyl-2-pyrrolidone, 7.2 g of sodium allyl sulfonate, 20.8 g of styrene, 20.0 g of methyl methacrylate, and 38.4 g of butyl acrylate were weighed and added to a 200 ml beaker. The mixture was stirred with a magnetic stirrer until the solution was clear and transparent to obtain a monomer mixture. 232 g of dioxane and 2.0 g of benzoyl peroxide were added to a 500 ml three-necked flask equipped with a thermometer, reflux condenser, and stirrer. The mixture was stirred at 350 rpm for 10 minutes. When the solution was clear and transparent, it was heated in a water bath. When the temperature reached 55 °C, the monomer mixture was added. The temperature was raised to 80 ± 1 °C and maintained at this temperature for 2 hours. The temperature was then raised to 90 ± 1 °C and maintained at this temperature for 1 hour. The reaction was then stopped. The reaction system temperature was lowered to below 35°C using a water bath. The reaction solution was then removed and dried using a spray dryer to obtain a crude solid powder polymer product. The crude product was washed three times with a 5% NaOH aqueous solution and then dried in an oven at 120°C for 2 hours to obtain a random copolymer.

[0039] (2) Preparation of random copolymer solution: At room temperature, take a beaker, weigh 5.0g of the above random copolymer, add 40.0g of ethyl acetate, 35.0g of dimethyl carbonate and 10.0g of N,N-dimethylformamide, cover with plastic wrap and tie tightly with rubber band, and dissolve under magnetic stirring until clear and transparent to obtain a random copolymer solution with a solid content of 5%.

[0040] (3) Preparation of silver ion solution: At room temperature, take a beaker, weigh 5.0g of solid silver nitrate, add it to 95.0g of deionized water, and stir magnetically until clear and transparent to obtain a silver nitrate solution with a solid content of 5%.

[0041] (4) At room temperature, take a beaker and weigh 100.0g of the above random copolymer solution. While stirring with a magnetic stirrer, slowly add 6.3g of 5% silver nitrate solution. After the addition is complete, continue stirring for 30 minutes until the solution is clear and transparent to obtain a silver ion polymer with a silver ion content of 2000ppm for mildew prevention and sterilization.

[0042] The silver ion polymer described in this embodiment, used for mold prevention and sterilization, does not separate, precipitate, or change color after two years of storage.

[0043] Sterilization performance: The antibacterial rate determination in this invention was performed according to GB15979-2002. A 100cm × 100cm piece of leather was taken, and the aforementioned silver ion polymer for mildew prevention and sterilization was evenly applied to the leather surface using spraying or brushing. The surface was then placed at room temperature in the dark for 48 hours. Random samples were taken from the leather, and the antibacterial rate against *Escherichia coli*, *Staphylococcus aureus*, *Pseudomonas aeruginosa*, *Aspergillus niger*, and *Candida albicans* was measured to be over 99%. After six months of storage, the treated leather was tested again, and the antibacterial rate against *Escherichia coli*, *Staphylococcus aureus*, *Pseudomonas aeruginosa*, *Aspergillus niger*, and *Candida albicans* remained above 99%.

[0044] Example 2

[0045] A silver ion polymer for mildew prevention and sterilization includes a hydrophilic unsaturated monomer, a hydrophobic unsaturated monomer, and silver ions; the hydrophilic unsaturated monomer and the hydrophobic unsaturated monomer form a random copolymer; the silver ions are combined with the random copolymer by ionic bonds or chelation.

[0046] The hydrophilic unsaturated monomer is composed of the following raw materials: 0.4 mol methacrylic acid, 0.059 mol sodium methacrylate, and 0.051 mol 2-vinyl-4,6-diaminotriazine; the hydrophobic unsaturated monomer is composed of the following raw materials: 0.2 mol α-methylstyrene, 0.2 mol methyl methacrylate, and 0.09 mol butyl acrylate. The total molar ratio of the hydrophilic to the hydrophobic unsaturated monomer is 51:49.

[0047] The preparation method of the silver ion polymer for mildew prevention and sterilization described in this embodiment includes the following steps:

[0048] (1) Preparation of random copolymers: At room temperature, 34.4 g of methacrylic acid, 9.3 g of sodium methacrylate, 7.0 g of 2-vinyl-4,6-diaminotriazine, 23.6 g of α-methylstyrene, 20.0 g of methyl methacrylate, and 11.5 g of butyl acrylate were weighed and added to a 200 ml beaker. The mixture was stirred with a magnetic stirrer until the solution was clear and transparent to obtain a monomer mixture. 247 g of dimethyl carbonate and 2.1 g of azobisisobutyronitrile were added to a 500 ml three-necked flask equipped with a thermometer, reflux condenser, and stirrer. The mixture was stirred at 350 rpm for 10 minutes. When the solution was clear and transparent, the mixture was heated in a water bath. When the temperature reached 55 °C, the monomer mixture was added. The temperature was raised to 80 ± 1 °C and maintained at this temperature for 2 hours. The temperature was then raised to 90 ± 1 °C and maintained at this temperature for 1 hour. The reaction was then stopped. The reaction system temperature was lowered to below 35°C using a water bath. The reaction solution was then removed and dried using a spray dryer to obtain a crude solid powder polymer product. The crude product was washed three times with a 5% NaOH aqueous solution and then dried in an oven at 120°C for 2 hours to obtain a random copolymer.

[0049] (2) Preparation of random copolymer solution: At room temperature, take a beaker, weigh 1.0g of the above random copolymer, add 50.0g of ethyl acetate, 39.0g of diethyl carbonate and 10.0g of tetrahydrofuran, cover with plastic wrap and tie tightly with rubber band, and dissolve under magnetic stirring until clear and transparent to obtain a random copolymer solution with a solid content of 1%.

[0050] (3) Preparation of silver ion solution: At room temperature, take a beaker, weigh 1.0g of solid silver nitrate, add it to 99.0g of distilled water, and stir magnetically until clear and transparent to obtain a silver nitrate solution with a solid content of 1%.

[0051] (4) At room temperature, take a beaker and weigh 100.0g of the above random copolymer solution. While stirring with a magnetic stirrer, slowly add 1.6g of 1% silver nitrate solution. After the addition is complete, continue stirring for 30 minutes until the solution is clear and transparent to obtain a silver ion polymer with a silver ion content of 100ppm for mildew prevention and sterilization.

[0052] The silver ion polymer described in this embodiment, used for mold prevention and sterilization, does not separate, precipitate, or change color after two years of storage.

[0053] Sterilization performance: The antibacterial rate determination in this invention was performed according to GB15979-2002. A 100cm × 100cm piece of pure cotton fabric was taken, and the aforementioned silver ion polymer for mildew prevention and sterilization was evenly coated onto the surface of the fabric using spraying or brushing methods. The fabric was then placed at room temperature in the dark for 48 hours. Random samples were taken from the pure cotton fabric, and the antibacterial rate against *Escherichia coli*, *Staphylococcus aureus*, *Pseudomonas aeruginosa*, *Aspergillus niger*, and *Candida albicans* was measured to be over 99%. After six months of storage, the treated pure cotton fabric was tested again, and the antibacterial rate against *Escherichia coli*, *Staphylococcus aureus*, *Pseudomonas aeruginosa*, *Aspergillus niger*, and *Candida albicans* remained above 99%.

[0054] Example 3

[0055] A silver ion polymer for mildew prevention and sterilization includes a hydrophilic unsaturated monomer, a hydrophobic unsaturated monomer, and silver ions; the hydrophilic unsaturated monomer and the hydrophobic unsaturated monomer form a random copolymer; the silver ions are combined with the random copolymer by ionic bonds or chelation.

[0056] The hydrophilic unsaturated monomer is 0.01 mol of methacrylic acid; the hydrophobic unsaturated monomer is composed of the following raw materials: 0.2 mol of styrene, 0.4 mol of methyl methacrylate, 0.2 mol of butyl acrylate, and 0.19 mol of isooctyl acrylate. The total molar ratio of the hydrophilic and hydrophobic unsaturated monomers is 1:99.

[0057] The preparation method of the silver ion polymer for mildew prevention and sterilization described in this embodiment includes the following steps:

[0058] (1) Preparation of random copolymer: At room temperature, 0.9 g of methacrylic acid, 20.8 g of styrene, 40.0 g of methyl methacrylate, 25.6 g of butyl acrylate, and 34.5 g of isooctyl acrylate were weighed and added to a 200 ml beaker. The mixture was stirred with a magnetic stirrer until the solution was clear and transparent, thus obtaining a monomer mixture. 280 g of dioxane and 2.4 g of azobisisobutyronitrile were added to a 500 ml three-necked flask equipped with a thermometer, reflux condenser, and stirrer. The mixture was stirred at 350 rpm for 10 minutes. When the solution became clear and transparent, the mixture was heated in a water bath. When the temperature reached 55 °C, the monomer mixture was added. The temperature was further increased to 80 ± 1 °C and maintained at this temperature for 2 hours. The temperature was then increased to 90 ± 1 °C and maintained at this temperature for 1 hour. The reaction was then stopped. The temperature of the reaction system was lowered to below 35 °C using a water bath. The reaction solution was removed and dried with a spray dryer to obtain a solid powder polymer crude product. The crude product was washed three times with a 5% NaOH aqueous solution and then dried in an oven at 120°C for 2 hours to obtain a random copolymer.

[0059] (2) Preparation of random copolymer solution: At room temperature, take a beaker, weigh 1.0g of the above random copolymer, add 40g of ethyl acetate, 39g of dimethyl carbonate and 10g of dioxane, cover with plastic wrap and tie tightly with rubber band, and dissolve under magnetic stirring until clear and transparent to obtain a random copolymer solution with a solid content of 1%.

[0060] (3) Preparation of silver ion solution: At room temperature, take a beaker, weigh 1g of solid silver oxide, add 10g of 5% dilute nitric acid solution, stir magnetically to dissolve until clear and transparent, add 89g of deionized water and stir evenly to obtain a silver-containing solution with a solid content of 1%.

[0061] (4) At room temperature, take a beaker and weigh 100.0g of the above random copolymer solution. While stirring with a magnetic stirrer, slowly add 5.4mg of the above solution containing silver ions. After the addition is complete, continue stirring for 30 minutes until the solution is clear and transparent to obtain a silver ion polymer with a silver ion content of 0.5ppm for mildew prevention and sterilization.

[0062] The silver ion polymer described in this embodiment, used for mold prevention and sterilization, does not separate, precipitate, or change color after two years of storage.

[0063] Sterilization performance: The antibacterial rate determination in this invention was performed according to GB15979-2002. A 100cm × 100cm piece of silk fabric was taken, and the aforementioned silver ion polymer for mildew prevention and sterilization was evenly coated onto the surface of the silk fabric using spraying or brushing methods. The fabric was placed at room temperature in the dark for 48 hours. Random samples were taken from the silk fabric, and the antibacterial rates against *Escherichia coli*, *Staphylococcus aureus*, *Pseudomonas aeruginosa*, *Aspergillus niger*, and *Candida albicans* were all determined to be above 99%, with antibacterial rates against *Aspergillus niger* and *Candida albicans* both above 90%. After six months of storage, the treated silk fabric was tested again, and the antibacterial rates against *Escherichia coli*, *Staphylococcus aureus*, *Pseudomonas aeruginosa*, *Aspergillus niger*, and *Candida albicans* were all reduced to below 90%.

[0064] Example 4

[0065] A silver ion polymer for mildew prevention and sterilization includes a hydrophilic unsaturated monomer, a hydrophobic unsaturated monomer, and silver ions; the hydrophilic unsaturated monomer and the hydrophobic unsaturated monomer form a random copolymer; the silver ions are combined with the random copolymer by ionic bonds or chelation.

[0066] The hydrophilic unsaturated monomer is composed of the following raw materials: 0.45 mol maleic anhydride and 0.05 mol acrylamide; the hydrophobic unsaturated monomer is composed of the following raw materials: 0.45 mol styrene and 0.05 mol butyl acrylate. The total molar ratio of the hydrophilic unsaturated monomer to the hydrophobic unsaturated monomer is 50:50.

[0067] The preparation method of the silver ion polymer for mildew prevention and sterilization described in this embodiment includes the following steps:

[0068] (1) Preparation of random copolymer: At room temperature, 44.1 g of maleic anhydride, 3.6 g of acrylamide, 46.8 g of styrene, and 6.4 g of butyl acrylate were weighed and added to a 200 ml beaker and mixed evenly with a magnetic stirrer to obtain a monomer mixture. 235 g of dimethyl carbonate and 2.0 g of benzoyl peroxide were added to a 500 ml three-necked flask equipped with a thermometer, reflux condenser, and stirrer. The mixture was stirred at 350 rpm for 10 minutes. When the solution became clear and transparent, it was heated in a water bath. When the temperature reached 55 °C, the monomer mixture was added, and the temperature was further increased to 80 ± 1 °C. The reaction was maintained at this temperature for 2 hours. The temperature was then increased to 90 ± 1 °C and maintained at this temperature for 1 hour. The reaction was then stopped. The temperature of the reaction system was lowered to below 35 °C using a water bath. The reaction solution was removed and dried with a spray dryer to obtain a solid powder polymer crude product. The crude product was washed three times with a 5% NaOH aqueous solution and then dried in an oven at 120°C for 2 hours to obtain a random copolymer.

[0069] (2) Preparation of random copolymer solution: At room temperature, take a beaker, weigh 5.0g of the above random copolymer, add 93.0g of deionized water and 2.0g of solid sodium hydroxide, cover with plastic wrap and tie tightly with rubber band, and dissolve under magnetic stirring until clear and transparent to obtain a random copolymer solution with a solid content of 5%.

[0070] (3) Preparation of silver ion solution: At room temperature, take a beaker, weigh 5.0g of solid silver nitrate, add it to 95.0g of distilled water, and stir magnetically until clear and transparent to obtain a 5% silver nitrate solution.

[0071] (4) At room temperature, take a beaker and weigh 100.0g of the above random copolymer solution. While stirring with a magnetic stirrer, slowly add 15.8g of 5% silver nitrate solution. After the addition is complete, continue stirring for 30 minutes until the solution is clear and transparent to obtain a silver ion polymer with a silver ion content of 5000ppm for mildew prevention and sterilization.

[0072] The silver ion polymer described in this embodiment, used for mold prevention and sterilization, does not separate, precipitate, or change color after two years of storage.

[0073] Bactericidal performance: The antibacterial rate determination in this invention was performed according to GB15979-2002. A 100cm×100cm polyester film was taken, and the above-mentioned silver ion polymer for mildew prevention and sterilization was uniformly coated on the surface of the polyester film by spraying or brushing. The film was then placed at room temperature in the dark for 48 hours. Random samples were taken from the polyester film, and the antibacterial rate against *Escherichia coli*, *Staphylococcus aureus*, *Pseudomonas aeruginosa*, *Aspergillus niger*, and *Candida albicans* was measured to be over 99%. After six months of storage, the treated polyester film was tested again, and the antibacterial rate against *Escherichia coli*, *Staphylococcus aureus*, *Pseudomonas aeruginosa*, *Aspergillus niger*, and *Candida albicans* still exceeded 99%.

[0074] Example 5

[0075] A silver ion polymer for mildew prevention and sterilization includes a hydrophilic unsaturated monomer, a hydrophobic unsaturated monomer, and silver ions; the hydrophilic unsaturated monomer and the hydrophobic unsaturated monomer form a random copolymer; the silver ions are combined with the random copolymer by ionic bonds or chelation.

[0076] The hydrophilic unsaturated monomer is composed of the following raw materials: 0.24 mol acrylic acid, 0.3 mol sodium allyl sulfonate, 0.03 mol N-(1-hydroxy-2,2-dimethoxyethyl)-2-acrylamide, and 0.03 mol acrylamide; the hydrophobic unsaturated monomer is composed of the following raw materials: 0.2 mol methyl methacrylate and 0.2 mol butyl acrylate. The total molar ratio of the hydrophilic unsaturated monomer to the hydrophobic unsaturated monomer is 60:40.

[0077] The preparation method of the silver ion polymer for mildew prevention and sterilization described in this embodiment includes the following steps:

[0078] (1) Preparation of random copolymers: At room temperature, 17.3 g of acrylic acid, 43.2 g of sodium allyl sulfonate, 5.3 g of N-(1-hydroxy-2,2-dimethoxyethyl)-2-acrylamide, 2.1 g of acrylamide, 20.0 g of methyl methacrylate, and 25.56 g of butyl acrylate were weighed and added to a 200 ml beaker. The mixture was stirred evenly with a magnetic stirrer to obtain a monomer mixture. 170 g of deionized water, 95 g of dimethylformamide, and 2.3 g of potassium persulfate were added to a 500 ml three-necked flask equipped with a thermometer, reflux condenser, and stirrer. The mixture was stirred at 350 rpm for 10 minutes. When the solution became clear and transparent, it was heated in a water bath. When the temperature reached 55 °C, the monomer mixture was added. The temperature was raised to 80 ± 1 °C and maintained at this temperature for 2 hours. The temperature was then raised to 90 ± 1 °C and maintained at this temperature for 1 hour. The reaction was then stopped. The reaction system temperature was lowered to below 35°C using a water bath. The reaction solution was then removed and dried using a spray dryer to obtain a crude solid powder polymer product. The crude product was washed three times with a 5% NaOH aqueous solution and then dried in an oven at 120°C for 2 hours to obtain a random copolymer.

[0079] (2) Preparation of random copolymer solution: At room temperature, take a beaker, weigh 2.0g of the above random copolymer, add 97.9g of deionized water and 0.1g of solid sodium hydroxide, cover with plastic wrap and tie tightly with rubber band, and dissolve under magnetic stirring until clear and transparent to obtain a random copolymer solution with a solid content of 2%.

[0080] (3) Preparation of silver ion solution: At room temperature, take a beaker, weigh 1.0g of solid silver nitrate, add it to 99.0g of distilled water, and stir magnetically until clear and transparent to obtain a 1% silver nitrate solution.

[0081] (4) At room temperature, take a beaker and weigh 100.0g of the above random copolymer solution. While stirring with a magnetic stirrer, slowly add 0.8g of 1% silver nitrate solution. After the addition is complete, continue stirring for 30 minutes until the solution is clear and transparent to obtain a silver ion polymer with a silver ion content of 50ppm for mildew prevention and sterilization.

[0082] The silver ion polymer described in this embodiment, used for mold prevention and sterilization, does not separate, precipitate, or change color after two years of storage.

[0083] Sterilization performance: The antibacterial rate determination in this invention was performed according to GB15979-2002. A 100cm×100cm spandex fabric was taken, and the above-mentioned silver ion polymer for mildew prevention and sterilization was uniformly coated on the surface of the spandex fabric by spraying or brushing. The fabric was then placed at room temperature in the dark for 48 hours. Randomly selected points on the spandex fabric were sampled, and the antibacterial rate against Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Aspergillus niger, and Candida albicans was measured to be over 99%. After the treated spandex fabric was placed for six months, it was tested again, and the antibacterial rate against Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Aspergillus niger, and Candida albicans remained above 99%.

[0084] Example 6

[0085] A silver ion polymer for mildew prevention and sterilization includes a hydrophilic unsaturated monomer, a hydrophobic unsaturated monomer, and silver ions; the hydrophilic unsaturated monomer and the hydrophobic unsaturated monomer form a random copolymer; the silver ions are combined with the random copolymer by ionic bonds or chelation.

[0086] The hydrophilic unsaturated monomer is composed of the following raw materials: 0.8 mol methacrylic acid, 0.18 mol maleic anhydride, and 0.01 mol acrylamide; the hydrophobic unsaturated monomer is composed of the following raw material: 0.01 mol methyl methacrylate. The total molar ratio of the hydrophilic to the hydrophobic unsaturated monomer is 99:1.

[0087] The preparation method of the silver ion polymer for mildew prevention and sterilization described in this embodiment includes the following steps:

[0088] (1) Preparation of random copolymer: At room temperature, 68.8 g of methacrylic acid, 17.6 g of maleic anhydride, 0.7 g of acrylamide, and 1.0 g of methyl methacrylate were weighed and added to a 200 ml beaker. The mixture was stirred with a magnetic stirrer until the solution was clear and transparent to obtain a monomer mixture. 205 g of deionized water and 1.8 g of ammonium persulfate were added to a 500 ml three-necked flask equipped with a thermometer, reflux condenser, and stirrer. The mixture was stirred at 350 rpm for 10 minutes. When the solution became clear and transparent, it was heated in a water bath. When the temperature reached 55 °C, the monomer mixture was added. The temperature was further increased to 80 ± 1 °C and maintained at this temperature for 2 hours. The temperature was then increased to 90 ± 1 °C and maintained at this temperature for 1 hour. The reaction was then stopped. The temperature of the reaction system was lowered to below 35 °C using a water bath. The reaction solution was removed and dried with a spray dryer to obtain a solid powder polymer crude product. The crude product was washed three times with a 5% NaOH aqueous solution and then dried in an oven at 120°C for 2 hours to obtain a random copolymer.

[0089] (2) Preparation of random copolymer solution: At room temperature, take a beaker, weigh 2.0g of the above random copolymer, add 97.0g of deionized water and 1.0g of solid sodium hydroxide, cover with plastic wrap and tie tightly with rubber band, and dissolve under magnetic stirring until clear and transparent to obtain a random copolymer solution with a solid content of 2%.

[0090] (3) Preparation of silver ion solution: At room temperature, take a beaker, weigh 5g of solid silver oxide, add 30g of 5% dilute nitric acid solution, stir magnetically to dissolve until clear and transparent, add 65g of deionized water and stir evenly to obtain a silver-containing solution with a solid content of 5%.

[0091] (4) At room temperature, take a beaker and weigh 100.0g of the above random copolymer solution. While stirring with a magnetic stirrer, slowly add 6.4g of 5% silver nitrate solution. After the addition is complete, continue stirring for 30 minutes until the solution is clear and transparent to obtain a silver ion polymer with a silver ion content of 3000ppm for anti-mildew and antibacterial purposes.

[0092] The silver ion polymer described in this embodiment, used for mold prevention and sterilization, does not separate, precipitate, or change color after two years of storage.

[0093] Sterilization performance: The antibacterial rate determination in this invention was performed according to GB15979-2002. A 100cm × 100cm acrylic fabric was taken, and the aforementioned silver ion polymer for mildew prevention and sterilization was uniformly coated onto the surface of the acrylic fabric using spraying or brushing methods. The fabric was then placed at room temperature in the dark for 48 hours. Random samples were taken from the acrylic fabric, and the antibacterial rates against *Escherichia coli*, *Staphylococcus aureus*, *Pseudomonas aeruginosa*, *Aspergillus niger*, and *Candida albicans* were all determined to be above 99%. After six months of storage, the treated acrylic fabric was tested again, and the antibacterial rates against *Escherichia coli*, *Staphylococcus aureus*, *Pseudomonas aeruginosa*, *Aspergillus niger*, and *Candida albicans* remained above 99%.

[0094] Example 7

[0095] A silver ion polymer for mildew prevention and sterilization includes a hydrophilic unsaturated monomer, a hydrophobic unsaturated monomer, and silver ions; the hydrophilic unsaturated monomer and the hydrophobic unsaturated monomer form a random copolymer; the silver ions are combined with the random copolymer by ionic bonds or chelation.

[0096] The hydrophilic unsaturated monomer is composed of the following raw materials: 0.045 mol methacrylic acid, 0.12 mol sodium methacrylate, 0.06 mol 2-vinyl-4,6-diaminotriazine, and 0.075 mol acrylamide; the hydrophobic unsaturated monomer is composed of the following raw materials: 0.1 mol styrene, 0.4 mol methyl methacrylate, and 0.2 mol butyl acrylate. The total molar ratio of the hydrophilic to the hydrophobic unsaturated monomer is 30:70.

[0097] The preparation method of the silver ion polymer for mildew prevention and sterilization described in this embodiment includes the following steps:

[0098] (1) Preparation of random copolymers: At room temperature, 3.9 g of methacrylic acid, 19.0 g of sodium methacrylate, 8.2 g of 2-vinyl-4,6-diaminotriazine, 5.3 g of acrylamide, 10.4 g of styrene, 40.0 g of methyl methacrylate and 25.6 g of butyl acrylate were weighed and added to a 200 ml beaker and mixed evenly with a magnetic stirrer to obtain a monomer mixture. 260 g of dioxane and 2.2 g of azobisisobutyronitrile were added to a 500 ml three-necked flask equipped with a thermometer, reflux condenser and stirrer. The mixture was stirred at 350 rpm for 10 minutes. When the solution became clear and transparent, it was heated in a water bath. When the temperature reached 55 °C, the monomer mixture was added, and the temperature was raised to 80 ± 1 °C. The reaction was maintained at this temperature for 2 hours. The temperature was then raised to 90 ± 1 °C and maintained at this temperature for 1 hour. The reaction was then stopped. The reaction system temperature was lowered to below 35°C using a water bath. The reaction solution was then removed and dried using a spray dryer to obtain a crude solid powder polymer product. The crude product was washed three times with a 5% NaOH aqueous solution and then dried in an oven at 120°C for 2 hours to obtain a random copolymer.

[0099] (2) Preparation of random copolymer solution: At room temperature, take a beaker, weigh 1.0g of the above random copolymer, add 50.0g of ethyl acetate, 30.0g of dimethyl carbonate and 19.0g of tetrahydrofuran, cover with plastic wrap and tie tightly with rubber band, and dissolve under magnetic stirring until clear and transparent to obtain a random copolymer solution with a solid content of 1%.

[0100] (3) Preparation of silver ion solution: At room temperature, take a beaker, weigh 1.0g of solid silver nitrate, add it to 99.0g of deionized water, and stir magnetically until clear and transparent to obtain a silver nitrate solution with a solid content of 1%.

[0101] (4) At room temperature, take a beaker and weigh 100.0g of the above random copolymer solution. While stirring with a magnetic stirrer, slowly add 16.0g of 1% silver nitrate solution. After the addition is complete, continue stirring for 30 minutes until the solution is clear and transparent to obtain a silver ion polymer with a silver ion content of 1000ppm for anti-mildew and antibacterial purposes.

[0102] The silver ion polymer described in this embodiment, used for mold prevention and sterilization, does not separate, precipitate, or change color after two years of storage.

[0103] Bactericidal performance: The antibacterial rate determination in this invention was performed according to GB15979-2002. A 100cm × 100cm wood chip was taken, and the aforementioned silver ion polymer for mildew prevention and sterilization was evenly coated onto the surface of the wood chip using a spraying or brushing method. The chip was then placed at room temperature in the dark for 48 hours. Random samples were taken from the wood chip, and the antibacterial rate against *Escherichia coli*, *Staphylococcus aureus*, *Pseudomonas aeruginosa*, *Aspergillus niger*, and *Candida albicans* was measured to be over 99%. After six months of storage, the treated wood chip was tested again, and the antibacterial rate against *Escherichia coli*, *Staphylococcus aureus*, *Pseudomonas aeruginosa*, *Aspergillus niger*, and *Candida albicans* remained above 99%.

[0104] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for preparing silver ion polymers for mildew prevention and sterilization, characterized in that, Includes the following steps: (1) Preparation of solid powdered random copolymers: The hydrophilic unsaturated monomer and the hydrophobic unsaturated monomer are mixed and stirred until the mixture is transparent to obtain the monomer mixture. First, mix the solvent and initiator and heat them. When the temperature reaches 55°C, add the monomer mixture and continue heating until the reaction system temperature is 80±1°C. Keep the temperature for 2 hours and then continue heating until the reaction system temperature is 90±1°C. Keep the temperature for 1 hour and then stop the reaction. The reaction solution was dried to a solid powder using a spray dryer, washed with a 5% NaOH aqueous solution, and then dried in an oven at 120°C for 2 hours to obtain a random copolymer. The mass ratio of the hydrophilic unsaturated monomer, the hydrophobic unsaturated monomer, the solvent, and the initiator is 0.9-87.1:1-120.9:205-280:1.8-2.4; The hydrophilic unsaturated monomer is at least one of sodium allyl sulfonate, sodium methacrylate sulfonate, 1-vinyl-2-pyrrolidone, 2-vinyl-4,6-diaminotriazine, maleic anhydride, methacrylic acid, acrylic acid, N-(1-hydroxy-2,2-dimethoxyethyl)-2-acrylamide, and acrylamide. The hydrophobic unsaturated monomer is at least one of styrene, α-methylstyrene, methyl methacrylate, butyl acrylate, and isooctyl acrylate; (2) Dissolving solid powdered random copolymer in aqueous solution or organic solvent: Dissolve the random copolymer obtained in step (1) in an aqueous solution or organic solvent with a pH of 6-8 and stir until transparent to obtain a random copolymer solution; When the molar ratio of hydrophilic unsaturated monomer to hydrophobic unsaturated monomer is 99:1-50:50, the random copolymer is soluble in an aqueous solution with a pH of 6-8 to form a transparent random copolymer solution. When the molar ratio of hydrophilic unsaturated monomer to hydrophobic unsaturated monomer is 49:51-1:99, the random copolymer is soluble in organic solvents to form a transparent random copolymer solution. (3) Preparation of silver ion solution: Dissolve silver nitrate in deionized water and stir until transparent to obtain silver ion solution; (4) Under stirring conditions, silver ion solution is added dropwise to random copolymer solution and stirred to carry out reaction, thereby obtaining the silver ion polymer used for anti-mildew and antibacterial purposes.

2. The method for preparing the silver ion polymer for mildew prevention and sterilization according to claim 1, characterized in that, In step (1), the solvent is at least one of dioxane, dimethyl carbonate, deionized water, and dimethylformamide.

3. The method for preparing the silver ion polymer for mildew prevention and sterilization according to claim 1, characterized in that, The initiator is at least one of potassium persulfate, ammonium persulfate, benzoyl peroxide, and azobisisobutyronitrile.

4. The method for preparing the silver ion polymer for mildew prevention and sterilization according to claim 1, characterized in that, In step (2), the organic solvent is at least one of dioxane, ethyl acetate, dimethyl carbonate, diethyl carbonate, N,N-dimethylformamide, and tetrahydrofuran; and the random copolymer solution has a mass percentage concentration of 1%-5% for the random copolymer.

5. The method for preparing the silver ion polymer for mildew prevention and sterilization according to claim 1, characterized in that, In step (3), the mass percentage concentration of silver nitrate in the silver ion solution is 1%-5%.