An antibacterial composite powder material and its preparation method

Abstract

This invention discloses an antibacterial composite powder material, which is a polyvinylpyrrolidone-silver ion-hydrogen peroxide complex prepared mainly by a complexation reaction of polyvinylpyrrolidone, silver salt, hydrogen peroxide, and a stabilizer. This antibacterial composite powder material obtains a vinylpyrrolidone-silver ion-hydrogen peroxide complex system by doubly complexing hydrogen peroxide and silver ions in a solid system with polyvinylpyrrolidone. This composite powder material can simultaneously and slowly release hydrogen peroxide and silver ions with a synergistic effect in the presence of water, exhibiting excellent antibacterial and antiviral effects. Furthermore, both silver ions and hydrogen peroxide can be stably complexed with polyvinylpyrrolidone, and the material can exist stably in an anhydrous state, exhibiting material stability and ease of storage, transportation, and use.

Description

Technical Field

[0001] This invention belongs to the field of disinfection product technology, specifically relating to an antibacterial composite powder material and its preparation method. Background Technology

[0002] Hydrogen peroxide is a common disinfectant effective against various bacteria and fungi, including spores. However, its effective concentration is relatively high, meaning its disinfection ability is relatively weak. Commonly used medical-grade hydrogen peroxide disinfectants contain up to 3% hydrogen peroxide. To be effective against spores, the concentration needs to be 5-10%, or even higher.

[0003] Furthermore, pure hydrogen peroxide is difficult to preserve and prone to explosion, thus requiring extremely stringent storage conditions. Therefore, aqueous solutions are generally used. However, aqueous solutions have a problem: hydrogen peroxide is not very stable and gradually decomposes during storage, leading to a decrease in effective concentration and consequently reducing its effectiveness.

[0004] Silver ions possess excellent antibacterial and antiviral capabilities, and are colorless, odorless, safe, and non-toxic. Furthermore, because silver ions are inorganic, they do not decompose or volatilize; in particular, they can be released after killing viruses and bacteria to continue their effects, thus exhibiting long-lasting efficacy.

[0005] Studies have shown that when silver ions are used in combination with hydrogen peroxide, they have a synergistic effect, resulting in good antibacterial and antiviral effects at extremely low concentrations of hydrogen peroxide and silver ions. However, the antibacterial effect still needs to be improved.

[0006] Currently, there are products on the market that combine silver ions and hydrogen peroxide, but they are all in the form of aqueous solutions, which also suffer from the problem of hydrogen peroxide decomposition and inactivation during storage. In addition, the storage and transportation costs of liquid materials are very high. Summary of the Invention

[0007] The purpose of this invention is to provide an antibacterial composite powder material that not only has excellent antibacterial properties but also high stability.

[0008] The following technical solutions are used to achieve the above objectives.

[0009] In a first aspect, the present invention provides an antibacterial composite powder material, wherein the antibacterial composite powder material is a polyvinylpyrrolidone-silver ion-hydrogen peroxide complex prepared mainly by a complexation reaction of polyvinylpyrrolidone, silver salt, hydrogen peroxide and stabilizer.

[0010] In some embodiments, the polyvinylpyrrolidone-silver ion-hydrogen peroxide complex prepared contains polyvinylpyrrolidone accounting for 55wt%-92.99wt% of the total amount, silver ions accounting for 0.01wt%-4wt% of the total amount, hydrogen peroxide accounting for 6wt%-35wt% of the total amount, and stabilizer accounting for 1wt%-6wt% of the total amount.

[0011] In some embodiments, the polyvinylpyrrolidone-silver ion-hydrogen peroxide complex prepared contains polyvinylpyrrolidone accounting for 62wt%-88.99wt% of the total, silver ions accounting for 0.01wt%-3wt% of the total, hydrogen peroxide accounting for 10wt%-30wt% of the total, and stabilizer accounting for 1wt%-5wt% of the total.

[0012] In some embodiments, the weight ratio of hydrogen peroxide to silver ions in the polyvinylpyrrolidone-silver ion-hydrogen peroxide complex is 10 to 1000:1.

[0013] In some embodiments, the weight ratio of hydrogen peroxide to silver ions is 15 to 1000:1.

[0014] In some embodiments, the silver salt is silver nitrate.

[0015] In some embodiments, the hydrogen peroxide is an aqueous solution of 30% and / or 50% by mass.

[0016] In some embodiments, the K value of the polyvinylpyrrolidone ranges from 30 to 100.

[0017] In some embodiments, the K value of the polyvinylpyrrolidone ranges from 30 to 50.

[0018] In some embodiments, the stabilizer is one or more of citric acid, tartaric acid, and inositol hexaphosphate.

[0019] In a second aspect, the present invention provides a method for preparing an antibacterial composite powder material as described above, comprising the following steps:

[0020] a. Mix and dissolve polyvinylpyrrolidone and anhydrous ethanol to obtain a polyvinylpyrrolidone anhydrous ethanol solution;

[0021] b. Mix and dissolve silver ions and anhydrous ethanol to obtain a silver ion anhydrous ethanol solution;

[0022] c. Dissolve the stabilizer in hydrogen peroxide solution to obtain stabilizer-hydrogen peroxide solution;

[0023] d. Add the stabilizer-hydrogen peroxide solution dropwise to the polyvinylpyrrolidone anhydrous ethanol solution, heat and stir in a water bath at 20-50℃ and reflux to obtain a complex solution;

[0024] e. Cool the complexing solution to room temperature, add anhydrous ethanol solution of silver ions dropwise into the complexing solution and stir, and finally dry at low temperature under vacuum or freeze-dry under vacuum to obtain antibacterial composite powder.

[0025] In some embodiments, during low-temperature vacuum drying, the vacuum drying temperature is 30-60°C, the vacuum degree is -0.1atm to -1atm, and the time is 12h-36h; preferably, the vacuum drying temperature is 42-48°C, the vacuum degree is -0.4atm to -0.6atm, and the time is 18h-24h.

[0026] In some embodiments, during freeze-drying, the freezer is pre-frozen for 0.5-5 hours at a temperature of -10°C to -60°C; after pre-freezing, the freezer is then frozen for 18-72 hours at a temperature of -20°C to -80°C, with a vacuum degree of 10-100 Pa.

[0027] Preferably, during freeze-drying, the freezer is pre-frozen for 1-3 hours at a temperature of -10°C to -30°C; after pre-freezing, it is then frozen for 24-48 hours at a temperature of -40°C to -60°C; and the vacuum degree during freezing is 10-50 Pa.

[0028] In some embodiments, in step d, the water bath is heated, stirred, and refluxed for 8-24 hours; and in step e, the stirring time is 15-60 minutes, preferably 25-35 minutes.

[0029] In this invention, it was discovered that polyvinylpyrrolidone (PVP) can be used to dual complex hydrogen peroxide and silver ions in a solid system. Furthermore, by optimizing the ratio of silver ions to hydrogen peroxide and controlling the preparation process parameters, especially the drying process parameters, a stable antibacterial composite powder material with a PPVP-silver ion-hydrogen peroxide complex system can be obtained. This antibacterial composite powder material can simultaneously and slowly release hydrogen peroxide and silver ions with a synergistic effect in the presence of water, exhibiting excellent antibacterial and antiviral properties. Moreover, both silver ions and hydrogen peroxide can be stably complexed with PPVP and can exist stably in an anhydrous state, exhibiting material stability and ease of storage, transportation, and use. Attached Figure Description

[0030] Figure 1 This is a photograph of the dried bulk material of the polyvinylpyrrolidone-silver ion-hydrogen peroxide complex obtained in Example 1.

[0031] Figure 2This is a photograph of the dried polyvinylpyrrolidone-silver ion-hydrogen peroxide complex obtained in Comparative Example 1.

[0032] Figure 3 This is a photograph of the dried polyvinylpyrrolidone-silver ion-hydrogen peroxide complex obtained in Comparative Example 2. Detailed Implementation

[0033] To facilitate understanding of the present invention, a more complete description will be provided below. The present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the present invention.

[0034] Unless otherwise specified, experimental methods in the following examples are generally performed under standard conditions or as recommended by the manufacturer. All commonly used chemical reagents used in the examples are commercially available products.

[0035] Unless otherwise defined, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. The term "and / or" as used in this invention includes any and all combinations of one or more of the associated listed items.

[0036] The following are specific examples.

[0037] Example 1

[0038] The preparation method of the antibacterial composite powder material provided in this embodiment includes the following steps:

[0039] 1) Add 89g of PVP-K30 (polyvinylpyrrolidone-K30, Gongbike New Material Technology (Shanghai) Co., Ltd.) and 90ml of anhydrous ethanol to a three-necked flask and stir to dissolve to obtain anhydrous ethanol solution of polyvinylpyrrolidone.

[0040] 2) 0.017g of silver nitrate was added to 10ml of anhydrous ethanol and stirred to dissolve, resulting in an anhydrous ethanol solution of silver ions;

[0041] 3) Add 1g of citric acid to 35g of 30% hydrogen peroxide aqueous solution (containing about 10g of hydrogen peroxide), stir to dissolve, and obtain a stable citric acid-hydrogen peroxide solution;

[0042] 4) The citric acid-hydrogen peroxide stable solution was added dropwise to the polyvinylpyrrolidone anhydrous ethanol solution, heated and stirred in a water bath at 25°C, and refluxed for 20 hours to obtain a hydrogen peroxide-polyvinylpyrrolidone complex solution.

[0043] 5) Cool the hydrogen peroxide-polyvinylpyrrolidone complex solution to room temperature, add anhydrous ethanol solution of silver ions dropwise to the hydrogen peroxide-polyvinylpyrrolidone complex solution, stir at room temperature for 30 min to obtain hydrogen peroxide-polyvinylpyrrolidone-silver ion complex solution.

[0044] 6) The obtained solution was vacuum dried in a vacuum drying oven at 45°C with a vacuum degree of -0.5 atm for 20 hours to obtain bulk material (see appendix). Figure 1 ), namely the polyvinylpyrrolidone-silver ion-hydrogen peroxide complex mentioned above.

[0045] 7) Grind the above-mentioned bulk material in a mortar to obtain an antibacterial composite powder material containing approximately 10 wt% hydrogen peroxide and approximately 0.01 wt% silver ions.

[0046] The hydrogen peroxide content was determined according to the method mentioned in Example 6, and the silver ion content was determined by flame atomic absorption spectrometry.

[0047] The steps of flame atomic absorption spectrometry are as follows:

[0048] The equipment is a Hitachi Z2000 atomic absorption spectrophotometer.

[0049] Experimental steps:

[0050] 1. Preparation of silver standard solution

[0051] 1) Dissolve 0.7875g of silver nitrate in 1% (vol) nitric acid solution, add to a volumetric flask, and dilute to 500ml with 1% nitric acid to obtain a standard solution of 1000mg / L.

[0052] 2) Plotting the standard solution curve

[0053] (1) Accurately measure 1.0, 2.0, 4.0, 8.0 and 10.0 ml of standard solution respectively, add them to 100 ml volumetric flasks respectively, and dilute to 100 ml with 1% nitric acid;

[0054] (2) Measure the absorbance of each concentration and plot the standard curve.

[0055] (3) The measured parameters are:

[0056] Wavelength: 328.1nm

[0057] Airflow rate: 6.5L / min

[0058] Acetylene flow rate: 1.0 L / min

[0059] Lamp current: 2mA

[0060] Spectral bandwidth: 0.4nm.

[0061] 3) Preparation of test solution and absorbance test

[0062] (1) Accurately measure 1g of composite powder and dissolve it in water to 10ml.

[0063] (2) Measure the absorbance of the solution according to the above parameters.

[0064] 4) Calculate the silver content

[0065] The silver content was obtained from the standard curve by plotting the absorbance of the composite powder solution on the x-axis.

[0066] Example 2

[0067] The powder material provided in this embodiment differs from that in Example 1 in that it does not contain silver ions. Its preparation method includes the following steps:

[0068] 1) Add 89g of PVP-K30 (polyvinylpyrrolidone-K30, Gongbike New Material Technology (Shanghai) Co., Ltd.) and 90ml of anhydrous ethanol to a three-necked flask and stir to dissolve to obtain anhydrous ethanol solution of polyvinylpyrrolidone.

[0069] 2) Add 1g of citric acid to 35g of 30% hydrogen peroxide aqueous solution (containing about 10g of hydrogen peroxide), stir to dissolve, and obtain a stable citric acid-hydrogen peroxide solution;

[0070] 3) The citric acid-hydrogen peroxide stable solution was added dropwise to the PVP anhydrous ethanol solution, heated and stirred in a water bath at 45°C, and refluxed for 10 hours to obtain a hydrogen peroxide-polyvinylpyrrol complex solution.

[0071] 4) The obtained solution was vacuum dried in a vacuum drying oven at 60°C with a vacuum degree of -0.1 atm for 36 hours to obtain bulk material;

[0072] 5) Grind and pulverize the above-mentioned bulk material to obtain a polyvinylpyrrolidone-hydrogen peroxide complex powder containing about 10% wt% hydrogen peroxide.

[0073] The hydrogen peroxide content was determined according to the determination method mentioned in Example 6.

[0074] Example 3

[0075] The powder material provided in this embodiment differs from that in Example 1 in that it does not contain hydrogen peroxide. Its preparation method includes the following steps:

[0076] 1) Add 100g PVP-K30 (polyvinylpyrrolidone-K30, Gongbike New Material Technology (Shanghai) Co., Ltd.) and 90ml anhydrous ethanol to a three-necked flask and stir to dissolve to obtain anhydrous ethanol solution of polyvinylpyrrolidone.

[0077] 2) Dissolve 0.017g of silver nitrate in 10ml of anhydrous ethanol by stirring to obtain an anhydrous ethanol solution of silver ions.

[0078] 3) Add silver ion anhydrous ethanol solution dropwise to polyvinylpyrrolidone anhydrous ethanol solution and stir at room temperature for 30 min to obtain polyvinylpyrrolidone-silver ion complex solution;

[0079] 4) The obtained solution was vacuum dried in a vacuum drying oven at 60°C with a vacuum degree of -1 atm for 24 hours to obtain a polyvinylpyrrolidone-silver ion complex powder material containing approximately 0.01 wt% silver ions.

[0080] The method for determining the silver ion content is the same as in Example 1.

[0081] Example 4

[0082] The powder material provided in this embodiment differs from that in Example 1 in that the content of hydrogen peroxide and silver ions in the antibacterial composite powder material is different. Its preparation method includes the following steps:

[0083] 1) Add 127g of PVP-K90 (polyvinylpyrrolidone-K90, Gongbike New Material Technology (Shanghai) Co., Ltd.) and 100ml of anhydrous ethanol to a three-necked flask and stir to dissolve to obtain anhydrous ethanol solution of polyvinylpyrrolidone.

[0084] 2) Dissolve 10.2g of silver nitrate in 300ml of anhydrous ethanol by stirring to obtain an anhydrous ethanol solution of silver ions.

[0085] 3) Add silver ion anhydrous ethanol solution dropwise to polyvinylpyrrolidone anhydrous ethanol solution and stir at room temperature for 30 min to obtain polyvinylpyrrolidone-silver ion complex solution;

[0086] 3) Add 3g of tartaric acid to 125g of 50% hydrogen peroxide aqueous solution (containing about 60g of hydrogen peroxide), stir to dissolve, and obtain a tartaric acid-hydrogen peroxide stable solution;

[0087] 4) Tartaric acid-hydrogen peroxide stable solution was added dropwise to PVP anhydrous ethanol solution, heated and stirred in a water bath at 35°C, and refluxed for 16 hours to obtain hydrogen peroxide-polyvinylpyrrolidone complex solution.

[0088] 5) Add anhydrous ethanol solution of silver ions dropwise to hydrogen peroxide-polyvinylpyrrolidone complex solution and stir at room temperature for 30 min to obtain hydrogen peroxide-polyvinylpyrrolidone-silver ion complex solution.

[0089] 6) The obtained solution was vacuum dried in a vacuum drying oven at 50°C with a vacuum degree of -0.5 atm for 20 hours to obtain a bulk material, namely the polyvinylpyrrolidone-silver ion-hydrogen peroxide complex mentioned above.

[0090] 7) Grind the above-mentioned bulk material in a mortar to obtain an antibacterial composite powder material containing approximately 30 wt% hydrogen peroxide and approximately 3 wt% silver ions.

[0091] The hydrogen peroxide content was determined according to the method mentioned in Example 6, and the silver ion content was determined according to the method in Example 1.

[0092] Example 5

[0093] The powder material provided in this embodiment differs from that in Example 1 in that the content of hydrogen peroxide and silver ions in the antibacterial composite powder material is different. Its preparation method includes the following steps:

[0094] 1) Add 75g PVP-K60 (polyvinylpyrrolidone-K30, Gongbike New Material Technology (Shanghai) Co., Ltd.) and 100ml anhydrous ethanol to a three-necked flask and stir to dissolve to obtain anhydrous ethanol solution of polyvinylpyrrolidone.

[0095] 2) 1.7g of silver nitrate was added to 100ml of anhydrous ethanol and stirred to dissolve, resulting in an anhydrous ethanol solution of silver ions;

[0096] 3) Add 10g of 50% inositol hexaphosphate to 70g of 30% hydrogen peroxide aqueous solution (containing about 20g of hydrogen peroxide), stir to dissolve, and obtain an inositol hexaphosphate-hydrogen peroxide stable solution;

[0097] 4) Tartaric acid-hydrogen peroxide stabilized solution was added dropwise to PVP anhydrous ethanol solution, heated and stirred in a 50°C water bath, and refluxed for 8 hours to obtain hydrogen peroxide-polyvinylpyrrolidone complex solution.

[0098] 5) Add anhydrous ethanol solution of silver ions dropwise to hydrogen peroxide-polyvinylpyrrolidone complex solution and stir at room temperature for 30 min to obtain hydrogen peroxide-polyvinylpyrrolidone-silver ion complex solution;

[0099] 6) The obtained solution was vacuum dried in a vacuum drying oven at 40°C with a vacuum degree of -0.5 atm for 20 hours to obtain a bulk material, namely the polyvinylpyrrolidone-silver ion-hydrogen peroxide complex mentioned above.

[0100] 7) Grind and pulverize the above-mentioned bulk material to obtain an antibacterial composite powder material containing approximately 20 wt% hydrogen peroxide and approximately 1 wt% silver ions.

[0101] The hydrogen peroxide content was determined according to the method mentioned in Example 6, and the silver ion content was determined according to the method in Example 1.

[0102] Example 6

[0103] The powder material provided in this embodiment differs from that in Example 1 in that the drying method of the complexation solution is different (freeze-vacuum drying). Its preparation method includes the following steps:

[0104] 1) Add 89g of PVP-K30 (polyvinylpyrrolidone-K30, Gongbike New Material Technology (Shanghai) Co., Ltd.) and 90ml of anhydrous ethanol to a three-necked flask and stir to dissolve to obtain anhydrous ethanol solution of polyvinylpyrrolidone.

[0105] 2) 0.017g of silver nitrate was added to 10ml of anhydrous ethanol and stirred to dissolve, resulting in an anhydrous ethanol solution of silver ions;

[0106] 3) Add 1g of citric acid to 35g of 30% hydrogen peroxide aqueous solution (containing approximately 10g of hydrogen peroxide), stir to dissolve, and obtain a stable citric acid-hydrogen peroxide solution.

[0107] 4) The citric acid-hydrogen peroxide stable solution was added dropwise to the PVP anhydrous ethanol solution, heated and stirred in a water bath at 25°C, and refluxed for 20 hours to obtain a hydrogen peroxide-polyvinylpyrrol complex solution.

[0108] 5) Add anhydrous ethanol solution of silver ions dropwise to hydrogen peroxide-polyvinylpyrrolidone complex solution and stir at room temperature for 30 min to obtain hydrogen peroxide-polyvinylpyrrolidone-silver ion complex solution.

[0109] 6) Pour the obtained solution into a pan, pre-freeze at -10℃ for 2 hours, then add it to a freeze dryer, freeze at -55℃ and vacuum at 10Pa for 24 hours to obtain the bulk material, namely the polyvinylpyrrolidone-silver ion-hydrogen peroxide complex mentioned above.

[0110] 7) Grind the above-mentioned bulk material in a mortar to obtain an antibacterial composite powder material containing approximately 10 wt% hydrogen peroxide and approximately 0.01 wt% silver ions.

[0111] The hydrogen peroxide content was determined according to the method mentioned in Example 6, and the silver ion content was determined according to the method in Example 1.

[0112] Example 7

[0113] Experimental objective: To test the stability of hydrogen peroxide and 30% hydrogen peroxide solution in the powder material of Example 4.

[0114] Experimental methods:

[0115] 1. Take 10g of the antibacterial composite powder material from Example 4 as the experimental group and 10g of 30% hydrogen peroxide solution as the control group, and add them to a 50ml beaker. Place the beaker in a water bath and control the water bath temperature at 60℃. At different time points, take 1g of antibacterial composite powder material or 1ml of hydrogen peroxide solution from the beaker and test the change in hydrogen peroxide content.

[0116] 2. Testing methods and procedures:

[0117] 1) Test reagents and samples:

[0118] (1) Standard solutions: 0.1M potassium permanganate, 3M sulfuric acid solution;

[0119] (2) Solution containing hydrogen peroxide:

[0120] Take 1g of antibacterial composite powder material from the experimental group or 1ml of 30% hydrogen peroxide solution from the control group, add water to 10ml and stir to dissolve, thus obtaining an aqueous solution containing hydrogen peroxide.

[0121] 2) Testing method:

[0122] (1) Add 4 ml of hydrogen peroxide aqueous solution to a 100 ml volumetric flask, dilute with deionized water to the mark, and shake well;

[0123] (2) Use a pipette to measure 3 ml of solution (1) and drop it into an Erlenmeyer flask;

[0124] (3) Add 10 ml of 3M sulfuric acid solution dropwise into the solution in (2);

[0125] (4) Titrate the solution in (3) with 0.1M potassium permanganate until the solution turns slightly red and the red color does not disappear within 30 seconds, then terminate the titration.

[0126] 3. Calculation of hydrogen peroxide (H2O2) content:

[0127] The reaction equation between H2O2 and KMnO4 is:

[0128] 2KMnO4+5H2O2+3H2SO4=2MnSO4+K2SO4+5O2+8H2O

[0129] Therefore, based on the amount of potassium permanganate solution used during the titration, the corresponding amount of hydrogen peroxide is calculated, and the content of hydrogen peroxide is calculated based on the dilution factor.

[0130] 4. Experimental results: Table 1 shows the changes in hydrogen peroxide content in Example 4 at 60℃ / 0h / 4h / 8h and in 30% hydrogen peroxide solution.

[0131] Table 1. Stability of the antibacterial composite powder material in Example 4 at 60°C with 30% hydrogen peroxide solution.

[0132]

[0133] As shown in Table 1 above, the antibacterial composite powder material of Example 4 released only 1.1% hydrogen peroxide after being heated in a water bath at 60°C for 8 hours. The release process was slow, indicating excellent stability. In contrast, the 30% hydrogen peroxide released as much as 9.7% after being heated in a water bath at 60°C for 8 hours, showing significantly lower stability compared to Example 4. This demonstrates that the antibacterial composite powder material of Example 4 is stable in an anhydrous state, facilitating storage, transportation, and use.

[0134] Example 8 (Testing antibacterial properties)

[0135] Experimental objective: To test the antibacterial properties of the antibacterial composite powder material of Example 1 against Escherichia coli, Staphylococcus aureus, and Candida albicans for 10 minutes by diluting the antibacterial composite powder material of Example 1 with water at 100 times, 1000 times, and 10000 times, respectively, and by diluting the powder materials of Examples 2 and 3 with water at 10000 times.

[0136] Experimental method: Refer to the "Disinfection Technical Specifications" (2002 edition):

[0137] (1) Preparation of test bacteria and bacterial solution

[0138] Test bacteria:

[0139] Bacteria: Staphylococcus aureus (ATCC 6538), Escherichia coli (8099 or ATCC 25922); Yeast: Candida albicans (ATCC 10231).

[0140] Preparation of contaminated sample slides: Fresh culture (18h-24h) of the nutrient agar slant from the 3rd to 14th generations of the strain was washed off with 5mL of 0.03mol / L phosphate-buffered saline (PBS). The bacterial growth was then diluted to the required concentration with the PBS. 100μl of the diluted PBS was dropped onto a sample slide (2.0cm×3.0cm) to achieve a recovered bacterial count of 1×10⁻⁶. 4 CFU / tablet ~ 9×10 4 cfu / film.

[0141] Preparation of bacterial suspension: Take fresh culture (18h-24h) of nutrient agar slant from the 3rd to 14th generation of the strain, wash off the bacterial growth with 5ml of 0.03mol / L phosphate buffer (hereinafter referred to as PBS), suspend the bacteria evenly, and then dilute with the above PBS to the required concentration.

[0142] (2) Neutralizing agent identification test: Refer to the quantitative identification test method for neutralizing agent carrier in the 2002 edition of "Disinfection Technical Specifications" - 2.1.1.5.

[0143] Bactericidal test: The quantitative bactericidal test method for carrier immersion was conducted according to the 2002 edition of the "Disinfection Technical Specifications" - 2.1.1.7.5. The specific operating steps are as follows:

[0144] (1) Wash the 24h slant culture of the test bacteria with PBS to prepare a bacterial suspension (the required concentration is: 100 μl is dropped onto the control sample, and the number of recovered bacteria is 1×10 4 cfu / slice to 9×10 4 cfu / slice).

[0145] (2) Take 4 test specimens (2.0cm×3.0cm) and 4 control specimens (material and size same as the test specimen, but without antibacterial material and sterilized), divide them into 4 groups and place them in 4 sterilized petri dishes.

[0146] (3) Take the above bacterial suspension and add 100 μl to each sample and control sample, spread evenly, start timing, and incubate for 30 min. Use sterile forceps to place the sample into a test tube containing 5 ml of the corresponding neutralizing agent, mix thoroughly, and dilute appropriately. Then take 2 to 3 dilutions, take 0.5 ml of each, place them in two petri dishes, and pour 15 ml of nutrient agar medium (bacteria) or Sabouraud agar medium (yeast) cooled to 40℃ to 45℃ into the dishes. Rotate the petri dishes to ensure even mixing. After the agar solidifies, invert the plates and incubate at 35℃ ± 2℃ for 48 h (bacteria) or 72 h (yeast). Count the viable colonies. Repeat the test 3 times and calculate the sterilization rate using the following formula:

[0147]

[0148] In the formula: X is the sterilization rate, %; N C The average colony count for the control sample is expressed as CFU / mL; N S The average colony count of the test sample is expressed in CFU / mL.

[0149] (4) Evaluation criteria: sterilization rate ≥90%, the product has sterilization effect.

[0150] Experimental results:

[0151] Table 2 shows the antibacterial effect of the powder materials in Examples 1 to 3 after 10 minutes.

[0152]

[0153]

[0154] As shown in Table 2 above, the powder material of Example 1 still has excellent antibacterial effect when diluted 10,000 times, with an antibacterial effect of nearly 99% against Escherichia coli, Staphylococcus aureus, and Candida albicans. However, the effect of the same concentration of polyvinylpyrrolidone-hydrogen peroxide complex powder solution and polyvinylpyrrolidone-silver ion complex powder solution is much worse. This indicates that hydrogen peroxide and silver ions in the powder material can exert excellent antibacterial effect when they work together, and there is a synergistic effect between the two.

[0155] Comparative Example 1

[0156] The powder material provided in this embodiment differs from that in Example 1 in that the drying method of the complexation solution is different (low-temperature drying at ambient pressure). Its preparation method includes the following steps:

[0157] 1) Add 89g of PVP-K30 (polyvinylpyrrolidone-K30, Gongbike New Material Technology (Shanghai) Co., Ltd.) and 90ml of anhydrous ethanol to a three-necked flask and stir to dissolve to obtain anhydrous ethanol solution of polyvinylpyrrolidone.

[0158] 2) 0.017g of silver nitrate was added to 10ml of anhydrous ethanol and stirred to dissolve, resulting in an anhydrous ethanol solution of silver ions;

[0159] 3) Add 1g of citric acid to 35g of 30% hydrogen peroxide aqueous solution (containing approximately 10g of hydrogen peroxide), stir to dissolve, and obtain a stable citric acid-hydrogen peroxide solution.

[0160] 4) The citric acid-hydrogen peroxide stable solution was added dropwise to the PVP anhydrous ethanol solution, heated and stirred in a water bath at 25°C, and refluxed for 20 hours to obtain a hydrogen peroxide-polyvinylpyrrol complex solution.

[0161] 5) Add anhydrous ethanol solution of silver ions dropwise to hydrogen peroxide-polyvinylpyrrolidone complex solution and stir at room temperature for 30 min to obtain hydrogen peroxide-polyvinylpyrrolidone-silver ion complex solution.

[0162] 6) Pour the obtained solution into a beaker, place it in a forced-air drying oven, and dry at 60°C. The complex solution cannot be completely dehydrated, and only a viscous gel (without flowability) can be obtained, but no powder material can be obtained (see the dried product). Figure 2 )

[0163] Comparative Example 2

[0164] The powder material provided in this embodiment differs from that in Example 1 in that the drying method of the complexation solution is different (atmospheric pressure and high temperature drying). Its preparation method includes the following steps:

[0165] 1) Add 89g of PVP-K30 (polyvinylpyrrolidone-K30) and 90ml of anhydrous ethanol to a three-necked flask and stir to dissolve to obtain anhydrous ethanol solution of polyvinylpyrrolidone;

[0166] 2) 0.017g of silver nitrate was added to 10ml of anhydrous ethanol and stirred to dissolve, resulting in an anhydrous ethanol solution of silver ions;

[0167] 3) Add 1g of citric acid to 35g of 30% hydrogen peroxide aqueous solution (containing approximately 10g of hydrogen peroxide), stir to dissolve, and obtain a stable citric acid-hydrogen peroxide solution.

[0168] 4) The citric acid-hydrogen peroxide stable solution was added dropwise to the PVP anhydrous ethanol solution, heated and stirred in a water bath at 25°C, and refluxed for 20 hours to obtain a hydrogen peroxide-polyvinylpyrrol complex solution.

[0169] 5) Add anhydrous ethanol solution of silver ions dropwise to hydrogen peroxide-polyvinylpyrrolidone complex solution and stir at room temperature for 30 min to obtain hydrogen peroxide-polyvinylpyrrolidone-silver ion complex solution.

[0170] 6) Pour the obtained solution into a beaker and place it in a forced-air drying oven at 110℃. During the drying process, hydrogen peroxide decomposes, producing a large number of bubbles (see...). Figure 3 Continue drying; hydrogen peroxide completely decomposes; silver ions undergo redox reaction with PVP at high temperature, turning into a brownish-brown blocky material. Stable hydrogen peroxide-polyvinylpyrrolidone-silver ion complex powder material cannot be obtained, and the preparation fails.

[0171] As demonstrated in Examples 1 and 6, low-temperature vacuum drying or freeze-vacuum drying can ensure the stable preparation of the antibacterial composite powder material. However, in Comparative Example 1, compared to Example 1, low-temperature drying at atmospheric pressure (below 100°C) failed to completely dry the water, resulting in a viscous gel-like substance. In Comparative Example 2, compared to Example 1, high-temperature drying at atmospheric pressure (above 100°C) did yield powder, but during the drying process, H₂O₂ decomposed, generating numerous bubbles. Further heating caused silver ions to undergo a redox reaction with PVP, ultimately turning the powder into a brownish-yellow color, leading to preparation failure. This indicates that controlling the preparation process parameters, especially the drying process parameters, has a significant impact on the preparation of stable antibacterial composite powder materials.

[0172] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0173] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A method for preparing an antibacterial composite powder material, characterized in that, The antibacterial composite powder material is a polyvinylpyrrolidone-silver ion-hydrogen peroxide complex prepared by complexation reaction of polyvinylpyrrolidone, silver salt, hydrogen peroxide and stabilizer, wherein the stabilizer is one or more of citric acid, tartaric acid and inositol hexaphosphate. The preparation method of the antibacterial composite powder material includes the following steps: a. Mix and dissolve polyvinylpyrrolidone and anhydrous ethanol to obtain a polyvinylpyrrolidone anhydrous ethanol solution; b. Dissolve silver salt in anhydrous ethanol to obtain an anhydrous ethanol solution of silver ions; c. Dissolve the stabilizer in hydrogen peroxide solution to obtain stabilizer-hydrogen peroxide solution; d. Add the stabilizer-hydrogen peroxide solution dropwise to the polyvinylpyrrolidone anhydrous ethanol solution, heat and stir in a water bath at 20-50°C, and reflux to obtain a complex solution; e. Cool the complexing solution to room temperature, add anhydrous ethanol solution of silver ions dropwise into the complexing solution and stir, and finally dry under low temperature vacuum or freeze-dry under vacuum to obtain antibacterial composite powder. In the prepared polyvinylpyrrolidone-silver ion-hydrogen peroxide complex, the polyvinylpyrrolidone accounts for 55wt%-92.99wt% of the total, the silver ions account for 0.01wt%-4wt% of the total, the hydrogen peroxide accounts for 6wt%-35wt% of the total, and the stabilizer accounts for 1wt%-6wt% of the total. In the polyvinylpyrrolidone-silver ion-hydrogen peroxide complex, the weight ratio of hydrogen peroxide to silver ions is 10~1000:

1. During low-temperature vacuum drying, the temperature is 42-48°C, the vacuum degree is -0.4atm to -0.6atm, and the time is 18h-24h. When freeze-drying, pre-freeze for 0.5-5 hours at a temperature of -10°C to -60°C; then freeze for 18-72 hours at a temperature of -20°C to -80°C, with a vacuum of 10-100 Pa.

2. The method for preparing the antibacterial composite powder material as described in claim 1, characterized in that, In the prepared polyvinylpyrrolidone-silver ion-hydrogen peroxide complex, the polyvinylpyrrolidone accounts for 62wt%-88.99wt% of the total, the silver ions account for 0.01wt%-3wt% of the total, the hydrogen peroxide accounts for 10wt%-30wt% of the total, and the stabilizer accounts for 1wt%-5wt% of the total.

3. The method for preparing the antibacterial composite powder material as described in claim 1, characterized in that, The weight ratio of hydrogen peroxide to silver ions is 15~1000:

1.

4. The method for preparing the antibacterial composite powder material as described in claim 1, characterized in that, The silver salt is silver nitrate.

5. The method for preparing the antibacterial composite powder material as described in claim 1, characterized in that, The hydrogen peroxide is an aqueous solution of hydrogen peroxide with a mass fraction of 30% or 50%.

6. The method for preparing the antibacterial composite powder material as described in claim 1, characterized in that, The K value of the polyvinylpyrrolidone is in the range of 30-100.

7. The method for preparing the antibacterial composite powder material as described in claim 6, characterized in that, The K value of the polyvinylpyrrolidone is in the range of 30-50.

8. The method for preparing the antibacterial composite powder material as described in claim 1, characterized in that, When freeze-drying, pre-freeze for 1-3 hours at a temperature of -10°C to -30°C; then freeze for 24-48 hours at a temperature of -40°C to -60°C; the vacuum level during freezing is 10-50 Pa.

Images