Method for preparing antibacterial resin from chitosan

Abstract

The invention discloses a method for preparing antibacterial resin from chitosan. The invention discloses a chitosan nano-silver adsorbent which is prepared from the following components in parts by mass: 4 to 6 parts of chitosan, 300 to 600 parts of dilute acetic acid solution, 0.05 to 0.15 part of nano-silver particles, 0.2 to 0.4 part of thymol, 3 to 5 parts of absolute ethyl alcohol, 0.7 to 0.9 part of beta-cyclodextrin, 2 to 3 parts of glutaraldehyde, 0.1 to 0.3 part of anhydrous citric acid, 2 to 2.2 parts of sodium bicarbonate and 2100 to 2300 parts of deionized water. The invention relates to the technical field of high polymer materials. According to the preparation method for preparing the antibacterial resin by utilizing the chitosan, the chitosan has natural antibacterial property, the nano-silver can strengthen the sterilization effect by destroying microbial cell membranes, and the thymol can specifically inhibit bacterial metabolism; meanwhile, due to the inclusion effect of beta-cyclodextrin on thymol, the volatilization loss of thymol can be effectively reduced, the antibacterial aging is prolonged, the crosslinking degree of the resin is improved through the cooperation of citric acid and glutaraldehyde in the preparation process, the antibacterial component is stably fixed in the resin structure, and the situation that the antibacterial agent is separated out too fast in the use process is avoided.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, specifically to a method for preparing antibacterial resin using chitosan. Background Technology

[0002] With increasing public awareness of health and higher demands for food safety, the development of efficient, safe, and long-lasting antimicrobial materials has become a research hotspot in materials science. Antimicrobial materials have broad application prospects in medical care, food packaging, household goods, and textiles, especially naturally derived antimicrobial materials which have attracted significant attention due to their excellent biocompatibility and environmental friendliness.

[0003] Chitosan, a natural alkaline polysaccharide derived from the deacetylation of chitin, possesses excellent biocompatibility, biodegradability, and natural antibacterial properties, making it an ideal substrate for antibacterial materials. However, the antibacterial properties of pure chitosan are limited, failing to meet the antibacterial requirements in complex environments, and its mechanical properties and chemical stability need improvement. To address this issue, researchers often enhance its antibacterial effect through the use of composite antibacterial agents.

[0004] To address the aforementioned issues, developing a chitosan-based antibacterial material with synergistic antibacterial effects, long-lasting stability, safety, non-toxicity, and optimized processing has become an urgent research need. This invention aims to solve the problems of insufficient antibacterial effect, poor stability, safety risks, and low production efficiency of existing chitosan-based antibacterial materials through composite antibacterial system design, cross-linking process optimization, post-processing technology improvement, and product morphology control, thereby providing technical support for the widespread application of antibacterial materials. Summary of the Invention

[0005] To solve the above-mentioned technical problems, the present invention is implemented through the following technical solution:

[0006] An antibacterial resin, comprising the following components:

[0007] The ingredients are: 4-6 parts by weight of chitosan, 300-600 parts by weight of dilute acetic acid solution, 0.05-0.15 parts by weight of nano-silver particles, 0.2-0.4 parts by weight of thymol, 3-5 parts by weight of anhydrous ethanol, 0.7-0.9 parts by weight of β-cyclodextrin, 2-3 parts by weight of glutaraldehyde, 0.1-0.3 parts by weight of anhydrous citric acid, 2-2.2 parts by weight of sodium bicarbonate, and 2100-2300 parts by weight of deionized water.

[0008] Preferably, the dilute acetic acid solution contains 1-2% glacial acetic acid, and the anhydrous ethanol has a volume fraction of 95%.

[0009] Preferably, it is composed of the following components:

[0010] The ingredients are: 5 parts by weight of chitosan, 450 parts by weight of dilute acetic acid solution, 0.1 parts by weight of nano-silver particles, 0.3 parts by weight of thymol, 4 parts by weight of anhydrous ethanol, 0.8 parts by weight of β-cyclodextrin, 2.5 parts by weight of glutaraldehyde, 0.2 parts by weight of anhydrous citric acid, 2.1 parts by weight of sodium bicarbonate, and 2200 parts by weight of deionized water.

[0011] A method for preparing antibacterial resin using chitosan includes the following steps:

[0012] Step A1: Raw material pretreatment;

[0013] Take chitosan, add nano-silver particles, grind in an agate mortar for 10 minutes, transfer to a vacuum drying oven to dry and sieve to obtain a chitosan-nano-silver mixture;

[0014] Step A2: Preparation of the composite antibacterial chitosan solution;

[0015] Weigh out thymol, dissolve it in anhydrous ethanol, and slowly add it dropwise into deionized water containing β-cyclodextrin. Stir magnetically for 1.5 hours to form a β-cyclodextrin-thymol inclusion complex solution.

[0016] Add the pretreated chitosan-nano silver mixture to a 1-2% dilute acetic acid solution and stir magnetically at room temperature for 3 hours. After complete dissolution, pour in the above β-cyclodextrin-thymol inclusion complex solution, continue stirring for 1 hour, and ultrasonically disperse for 15 minutes (power 300W) to obtain a transparent and uniform composite antibacterial chitosan solution.

[0017] Step A3: Preparation of composite crosslinking agent solution;

[0018] Take glutaraldehyde, dilute it with deionized water to 83 mL (mass fraction 3%), add anhydrous citric acid, and stir magnetically for 30 min until completely dissolved. Set aside. Citric acid works synergistically with glutaraldehyde to improve the crosslinking degree of the resin.

[0019] Step A4: Construction of the pre-reaction system;

[0020] Transfer the composite antibacterial chitosan solution to a three-necked flask, turn on the constant temperature magnetic stirrer at 300 r / min, control the temperature at 35℃, and add the composite crosslinking agent solution dropwise to the composite antibacterial chitosan solution at a chitosan to glutaraldehyde molar ratio of 1:0.8.

[0021] After the addition was complete, the temperature was increased to 55°C at a rate of 2°C / min, and stirred for 3 hours. Once a non-flowing gel was observed to form in the system, stirring was stopped.

[0022] Step A5: Post-processing;

[0023] Remove the gel, cut it into small pieces of 4mm×4mm-6mm×6mm, transfer it to a Buchner funnel, and sonicate it with deionized water at 200W for 15 minutes each time. Filter it three times to remove unreacted acetic acid.

[0024] Soak and wash twice with 0.5 mol / L sodium bicarbonate solution for 1.5 h each time to neutralize residual acid and prevent NaOH from damaging the nano-silver. Filter by suction.

[0025] Finally, the filtrate was ultrasonically washed with deionized water until the pH of the filtrate was 6.8±0.2, and the Schiff reagent test showed no aldehyde odor. The filtrate was then ready for use.

[0026] Step A6: Vacuum drying and molding;

[0027] The washed gel particles were transferred to a vacuum drying oven and dried at 45°C and 0.09 MPa for 10 hours until the particles reached a constant weight.

[0028] After drying, the resin is pulverized and passed through a 30-mesh sieve to obtain a light yellow powdery antibacterial resin.

[0029] Preferably, in step A1, the vacuum drying oven is set to a temperature of 65 degrees Celsius, a vacuum pressure of 0.09 MPa, and a drying time of 5 hours, and the dried product is passed through a 90-mesh sieve.

[0030] Preferably, the magnetic stirring operation in step A2 specifically adopts programmed temperature increase stirring, initially stirring at 25°C for 30 minutes, and then increasing to 35°C for 1 hour.

[0031] Preferably, in step A3, the anhydrous citric acid is pretreated before being added, specifically as follows:

[0032] Anhydrous citric acid was ground in a cryogenic grinder (-10℃) for 10 minutes and then passed through a 100-mesh sieve to obtain a fine powder. This increases the specific surface area.

[0033] Preferably, the specific steps for magnetic stirring for 30 minutes in step A3 are as follows:

[0034] Dissolve glutaraldehyde in 70% of the measured amount of deionized water to a mass fraction of 3%. Add citric acid powder and stir magnetically at 25°C for 15 minutes. Then add the remaining 30% of deionized water, raise the temperature to 30°C, and continue stirring for 15 minutes until completely dissolved. This can shorten the dissolution time to 2 / 3 of the original time and make the citric acid more evenly dispersed.

[0035] Preferably, in step A4, the composite crosslinking agent solution is slowly added to the composite antibacterial chitosan solution at a rate of 1.5 drops / second, and the addition process is continuously stirred for 1 hour. The addition position of the composite crosslinking agent solution is the center region of the vortex formed by the stir bar.

[0036] Preferably, after the non-flowing gel is formed in step A4, it is kept at 55°C for 2 hours and then cooled to room temperature for another 6 hours. This ensures that the cross-linking reaction is complete.

[0037] This invention provides a method for preparing antibacterial resin using chitosan. It has the following beneficial effects:

[0038] (I) The preparation method of antibacterial resin using chitosan achieves multi-mechanism synergistic antibacterial effect through the design of a composite antibacterial system:

[0039] Chitosan itself has natural antibacterial properties, nano-silver can enhance the bactericidal effect by disrupting the cell membrane of microorganisms, and thymol can specifically inhibit bacterial metabolism; at the same time, the inclusion effect of β-cyclodextrin on thymol can effectively reduce its volatilization and loss, and prolong the antibacterial effect.

[0040] In addition, the cross-linking degree of the resin is improved by citric acid and glutaraldehyde in the preparation process, so that the antibacterial components are stably fixed in the resin structure, avoiding the antibacterial agent from precipitating out too quickly during use, and further ensuring long-term antibacterial performance, which is suitable for scenarios where the duration of antibacterial inhibition is required.

[0041] (II) The method for preparing antibacterial resin using chitosan effectively reduces the risk of potential harmful substances by specifically optimizing the residue removal process in the post-processing stage:

[0042] First, deionized water ultrasonic washing and sodium bicarbonate solution neutralization are used instead of traditional NaOH neutralization. This avoids strong alkali damaging the nano-silver structure and causing antibacterial failure, and can also completely neutralize residual acetic acid to prevent acidic substances from irritating the skin.

[0043] Secondly, Schiff reagent testing was used to ensure that there was no residual aldehyde odor, eliminating the potential toxicity of glutaraldehyde, and finally controlling the pH of the filtrate to be stable at 6.8±0.2, with no unreacted small molecule residues.

[0044] This design makes the resin significantly safer than traditional antibacterial resins, allowing it to be extended to applications involving human contact or food.

[0045] (III) This method for preparing antibacterial resin using chitosan achieves improved production efficiency and stable product quality through multi-stage process optimization:

[0046] Firstly, anhydrous citric acid is pretreated by low-temperature freeze grinding and 100-mesh sieving, and then dissolved by stepwise water addition and gradient heating and stirring, which shortens the dissolution time to 2 / 3 of the original time and makes the citric acid more uniformly dispersed.

[0047] Secondly, step A2 uses programmed temperature increase and stirring, and step A4 controls the drop rate of 1.5 drops / second, plus programmed temperature increase and aging, to ensure that the cross-linking reaction is sufficient and the system is uniform, avoiding performance differences caused by local gelation.

[0048] Third, the combination of vacuum drying and sieving enables standardized powder forming, resulting in high batch-to-batch quality consistency and reducing the defect rate in industrial production.

[0049] (iv) This method for preparing antibacterial resin using chitosan, by producing a light yellow powdered antibacterial resin as the final product, has two major application advantages:

[0050] First, the powder has a large specific surface area, making it easy to mix evenly with other substrates. It can achieve antibacterial function composites without additional complex modifications and is compatible with a variety of processing techniques.

[0051] Secondly, by controlling the gel fragment size, ultrasonic washing parameters, and drying conditions during the preparation process, the powder particles are made uniform in size and have good flowability, which is convenient for storage and transportation. The addition ratio can also be adjusted according to different needs, and the application scenarios cover multiple fields such as home furnishing, medical care, food packaging, and textiles. Detailed Implementation

[0052] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0053] Example 1: The present invention provides a technical solution:

[0054] An antibacterial resin, comprising the following components:

[0055] The ingredients are: 4 parts by weight of chitosan, 300 parts by weight of dilute acetic acid solution, 0.05 parts by weight of nano-silver particles, 0.2 parts by weight of thymol, 3 parts by weight of anhydrous ethanol, 0.7 parts by weight of β-cyclodextrin, 2 parts by weight of glutaraldehyde, 0.1 parts by weight of anhydrous citric acid, 2 parts by weight of sodium bicarbonate, and 2100 parts by weight of deionized water.

[0056] A method for preparing antibacterial resin using chitosan includes the following steps:

[0057] Step A1: Raw material pretreatment;

[0058] Take chitosan, add nano-silver particles, grind in an agate mortar for 10 minutes, transfer to a vacuum drying oven to dry and sieve. The vacuum drying oven is set at a temperature of 65 degrees Celsius, a vacuum pressure of 0.09 MPa, and a drying time of 5 hours. After drying, pass through a 90-mesh sieve to obtain a chitosan-nano-silver mixture.

[0059] Step A2: Preparation of the composite antibacterial chitosan solution;

[0060] Weigh out thymol, dissolve it in anhydrous ethanol, and slowly add it dropwise into deionized water containing β-cyclodextrin. Stir magnetically for 1.5 hours to form a β-cyclodextrin-thymol inclusion complex solution.

[0061] The magnetic stirring operation steps specifically adopt programmed temperature rise stirring, initially stirring at 25℃ for 30 minutes, and then rising to 35℃ and stirring for 1 hour;

[0062] The pretreated chitosan-nano silver mixture was added to a 1% dilute acetic acid solution and magnetically stirred at room temperature for 3 hours. After complete dissolution, the above β-cyclodextrin-thymol inclusion complex solution was poured in and stirred for another 1 hour. The mixture was then ultrasonically dispersed for 15 minutes (300W) to obtain a transparent and uniform composite antibacterial chitosan solution.

[0063] The inclusion complexation of thymol by β-cyclodextrin can effectively reduce its volatilization and loss, and prolong its antibacterial effect.

[0064] Step A3: Preparation of composite crosslinking agent solution;

[0065] Take glutaraldehyde, dilute it with deionized water to 83 mL, its mass fraction is 3%, add anhydrous citric acid, stir magnetically for 30 min until completely dissolved, and set aside; citric acid works synergistically with glutaraldehyde to improve the crosslinking degree of the resin; before adding anhydrous citric acid, the anhydrous citric acid is pretreated, specifically: place the anhydrous citric acid in a low-temperature cryogenic grinder (-10℃) and grind for 10 min, then pass it through a 100-mesh sieve to make micro powder, thereby increasing the specific surface area.

[0066] In the preparation process, citric acid and glutaraldehyde are used to enhance the cross-linking degree of the resin, so that the antibacterial components are stably fixed in the resin structure, avoiding the rapid precipitation of antibacterial agents during use, and further ensuring long-term antibacterial performance. This method is suitable for scenarios where antibacterial duration is required.

[0067] Chitosan itself has natural antibacterial properties, nano-silver can enhance the bactericidal effect by destroying the cell membrane of microorganisms, and thymol can specifically inhibit bacterial metabolism.

[0068] The specific steps for magnetic stirring for 30 minutes until completely dissolved are as follows:

[0069] Dissolve glutaraldehyde in 70% of the measured amount of deionized water to a mass fraction of 3%. Add citric acid powder and stir magnetically at 25°C for 15 minutes. Then add the remaining 30% of deionized water, raise the temperature to 30°C, and continue stirring for 15 minutes until completely dissolved. This can shorten the dissolution time to 2 / 3 of the original time and make the citric acid more evenly dispersed.

[0070] Step A4: Construction of the pre-reaction system;

[0071] Transfer the composite antibacterial chitosan solution to a three-necked flask, turn on the constant temperature magnetic stirrer at 300 r / min, control the temperature at 35℃, and slowly add the composite crosslinking agent solution to the composite antibacterial chitosan solution at a rate of 1.5 drops / second according to the chitosan to glutaraldehyde molar ratio of 1:0.8. Continue stirring for 1 hour during the addition process. The addition position of the composite crosslinking agent solution is the center area of ​​the vortex formed by the stir bar.

[0072] After the addition is complete, the temperature is increased to 55°C at a rate of 2°C / min, and stirred at this temperature for 3 hours. Once a non-flowing gel is observed to form, stirring is stopped, and the mixture is allowed to stand at 55°C for 2 hours. Then, the temperature is lowered to room temperature and aged for another 6 hours to ensure a complete cross-linking reaction.

[0073] Step A5: Post-processing;

[0074] Remove the gel, cut it into small pieces of 4mm×4mm, transfer it to a Buchner funnel, and sonicate it with deionized water at 200W for 15 minutes each time. Filter it three times to remove unreacted acetic acid.

[0075] Soak and wash twice with 0.5 mol / L sodium bicarbonate solution for 1.5 h each time to neutralize residual acid and prevent NaOH from damaging the nano-silver. Filter by suction.

[0076] Finally, the filtrate was ultrasonically washed with deionized water until the pH of the filtrate was 6.8±0.2, and the Schiff reagent test showed no aldehyde odor. The filtrate was then ready for use.

[0077] Step A6: Vacuum drying and molding;

[0078] The washed gel particles were transferred to a vacuum drying oven and dried at 45°C and 0.09 MPa for 10 hours until the particles reached a constant weight.

[0079] After drying, the resin is pulverized and passed through a 30-mesh sieve to obtain a light yellow powdery antibacterial resin.

[0080] Example 2: Based on Example 1, the present invention provides a technical solution:

[0081] An antibacterial resin, comprising the following components:

[0082] The ingredients are: 6 parts by weight of chitosan, 600 parts by weight of dilute acetic acid solution, 0.15 parts by weight of nano-silver particles, 0.4 parts by weight of thymol, 5 parts by weight of anhydrous ethanol, 0.9 parts by weight of β-cyclodextrin, 3 parts by weight of glutaraldehyde, 0.3 parts by weight of anhydrous citric acid, 2.2 parts by weight of sodium bicarbonate, and 2300 parts by weight of deionized water.

[0083] A method for preparing antibacterial resin using chitosan includes the following steps:

[0084] Step A1: Raw material pretreatment;

[0085] Take chitosan, add nano-silver particles, grind in an agate mortar for 10 minutes, transfer to a vacuum drying oven to dry and sieve. The vacuum drying oven is set at a temperature of 65 degrees Celsius, a vacuum pressure of 0.09 MPa, and a drying time of 5 hours. After drying, pass through a 90-mesh sieve to obtain a chitosan-nano-silver mixture.

[0086] Step A2: Preparation of the composite antibacterial chitosan solution;

[0087] Weigh out thymol, dissolve it in anhydrous ethanol, and slowly add it dropwise into deionized water containing β-cyclodextrin. Stir magnetically for 1.5 hours to form a β-cyclodextrin-thymol inclusion complex solution.

[0088] The magnetic stirring operation steps specifically adopt programmed temperature rise stirring, initially stirring at 25℃ for 30 minutes, and then rising to 35℃ and stirring for 1 hour;

[0089] The pretreated chitosan-nano silver mixture was added to a 2% dilute acetic acid solution and magnetically stirred at room temperature for 3 hours. After complete dissolution, the above β-cyclodextrin-thymol inclusion complex solution was poured in and stirred for another 1 hour. The mixture was then ultrasonically dispersed for 15 minutes (300W) to obtain a transparent and uniform composite antibacterial chitosan solution.

[0090] The inclusion complexation of thymol by β-cyclodextrin can effectively reduce its volatilization and loss, and prolong its antibacterial effect.

[0091] Step A3: Preparation of composite crosslinking agent solution;

[0092] Take glutaraldehyde, dilute it with deionized water to 83 mL, its mass fraction is 3%, add anhydrous citric acid, stir magnetically for 30 min until completely dissolved, and set aside; citric acid works synergistically with glutaraldehyde to improve the crosslinking degree of the resin; before adding anhydrous citric acid, the anhydrous citric acid is pretreated, specifically: place the anhydrous citric acid in a low-temperature cryogenic grinder (-10℃) and grind for 10 min, then pass it through a 100-mesh sieve to make micro powder, thereby increasing the specific surface area.

[0093] In the preparation process, citric acid and glutaraldehyde are used to enhance the cross-linking degree of the resin, so that the antibacterial components are stably fixed in the resin structure, avoiding the rapid precipitation of antibacterial agents during use, and further ensuring long-term antibacterial performance. This method is suitable for scenarios where antibacterial duration is required.

[0094] Chitosan itself has natural antibacterial properties, nano-silver can enhance the bactericidal effect by destroying the cell membrane of microorganisms, and thymol can specifically inhibit bacterial metabolism.

[0095] The specific steps for magnetic stirring for 30 minutes until completely dissolved are as follows:

[0096] Dissolve glutaraldehyde in 70% of the measured amount of deionized water to a mass fraction of 3%. Add citric acid powder and stir magnetically at 25°C for 15 minutes. Then add the remaining 30% of deionized water, raise the temperature to 30°C, and continue stirring for 15 minutes until completely dissolved. This can shorten the dissolution time to 2 / 3 of the original time and make the citric acid more evenly dispersed.

[0097] Step A4: Construction of the pre-reaction system;

[0098] Transfer the composite antibacterial chitosan solution to a three-necked flask, turn on the constant temperature magnetic stirrer at 300 r / min, control the temperature at 35℃, and slowly add the composite crosslinking agent solution to the composite antibacterial chitosan solution at a rate of 1.5 drops / second according to the chitosan to glutaraldehyde molar ratio of 1:0.8. Continue stirring for 1 hour during the addition process. The addition position of the composite crosslinking agent solution is the center area of ​​the vortex formed by the stir bar.

[0099] After the addition is complete, the temperature is increased to 55°C at a rate of 2°C / min, and stirred at this temperature for 3 hours. Once a non-flowing gel is observed to form, stirring is stopped, and the mixture is allowed to stand at 55°C for 2 hours. Then, the temperature is lowered to room temperature and aged for another 6 hours to ensure a complete cross-linking reaction.

[0100] Step A5: Post-processing;

[0101] Remove the gel, cut it into small pieces of 6mm×6mm, transfer it to a Buchner funnel, and sonicate it with deionized water at 200W for 15 minutes each time. Filter it three times to remove unreacted acetic acid.

[0102] Soak and wash twice with 0.5 mol / L sodium bicarbonate solution for 1.5 h each time to neutralize residual acid and prevent NaOH from damaging the nano-silver. Filter by suction.

[0103] Finally, the filtrate was ultrasonically washed with deionized water until the pH of the filtrate was 6.8±0.2, and the Schiff reagent test showed no aldehyde odor. The filtrate was then ready for use.

[0104] Step A6: Vacuum drying and molding;

[0105] The washed gel particles were transferred to a vacuum drying oven and dried at 45°C and 0.09 MPa for 10 hours until the particles reached a constant weight.

[0106] After drying, the resin is pulverized and passed through a 30-mesh sieve to obtain a light yellow powdery antibacterial resin.

[0107] Example 3: Based on Examples 1 and 2, the present invention provides a technical solution:

[0108] An antibacterial resin, comprising the following components:

[0109] The ingredients are: 5 parts by weight of chitosan, 450 parts by weight of dilute acetic acid solution, 0.1 parts by weight of nano-silver particles, 0.3 parts by weight of thymol, 4 parts by weight of anhydrous ethanol, 0.8 parts by weight of β-cyclodextrin, 2.5 parts by weight of glutaraldehyde, 0.2 parts by weight of anhydrous citric acid, 2.1 parts by weight of sodium bicarbonate, and 2200 parts by weight of deionized water.

[0110] A method for preparing antibacterial resin using chitosan includes the following steps:

[0111] Step A1: Raw material pretreatment;

[0112] Take chitosan, add nano-silver particles, grind in an agate mortar for 10 minutes, transfer to a vacuum drying oven to dry and sieve. The vacuum drying oven is set at a temperature of 65 degrees Celsius, a vacuum pressure of 0.09 MPa, and a drying time of 5 hours. After drying, pass through a 90-mesh sieve to obtain a chitosan-nano-silver mixture.

[0113] Step A2: Preparation of the composite antibacterial chitosan solution;

[0114] Weigh out thymol, dissolve it in anhydrous ethanol, and slowly add it dropwise into deionized water containing β-cyclodextrin. Stir magnetically for 1.5 hours to form a β-cyclodextrin-thymol inclusion complex solution.

[0115] The magnetic stirring operation steps specifically adopt programmed temperature rise stirring, initially stirring at 25℃ for 30 minutes, and then rising to 35℃ and stirring for 1 hour;

[0116] The pretreated chitosan-silver nano mixture was added to a 1.5% dilute acetic acid solution and magnetically stirred at room temperature for 3 hours. After complete dissolution, the above β-cyclodextrin-thymol inclusion complex solution was poured in and stirred for another hour. The mixture was then ultrasonically dispersed for 15 minutes (300W) to obtain a transparent and uniform composite antibacterial chitosan solution.

[0117] The inclusion complexation of thymol by β-cyclodextrin can effectively reduce its volatilization and loss, and prolong its antibacterial effect.

[0118] Step A3: Preparation of composite crosslinking agent solution;

[0119] Take glutaraldehyde, dilute it with deionized water to 83 mL, its mass fraction is 3%, add anhydrous citric acid, stir magnetically for 30 min until completely dissolved, and set aside; citric acid works synergistically with glutaraldehyde to improve the crosslinking degree of the resin; before adding anhydrous citric acid, the anhydrous citric acid is pretreated, specifically: place the anhydrous citric acid in a low-temperature cryogenic grinder (-10℃) and grind for 10 min, then pass it through a 100-mesh sieve to make micro powder, thereby increasing the specific surface area.

[0120] In the preparation process, citric acid and glutaraldehyde are used to enhance the cross-linking degree of the resin, so that the antibacterial components are stably fixed in the resin structure, avoiding the rapid precipitation of antibacterial agents during use, and further ensuring long-term antibacterial performance. This method is suitable for scenarios where antibacterial duration is required.

[0121] Chitosan itself has natural antibacterial properties, nano-silver can enhance the bactericidal effect by destroying the cell membrane of microorganisms, and thymol can specifically inhibit bacterial metabolism.

[0122] The specific steps for magnetic stirring for 30 minutes until completely dissolved are as follows:

[0123] Dissolve glutaraldehyde in 70% of the measured amount of deionized water to a mass fraction of 3%. Add citric acid powder and stir magnetically at 25°C for 15 minutes. Then add the remaining 30% of deionized water, raise the temperature to 30°C, and continue stirring for 15 minutes until completely dissolved. This can shorten the dissolution time to 2 / 3 of the original time and make the citric acid more evenly dispersed.

[0124] Step A4: Construction of the pre-reaction system;

[0125] Transfer the composite antibacterial chitosan solution to a three-necked flask, turn on the constant temperature magnetic stirrer at 300 r / min, control the temperature at 35℃, and slowly add the composite crosslinking agent solution to the composite antibacterial chitosan solution at a rate of 1.5 drops / second according to the chitosan to glutaraldehyde molar ratio of 1:0.8. Continue stirring for 1 hour during the addition process. The addition position of the composite crosslinking agent solution is the center area of ​​the vortex formed by the stir bar.

[0126] After the addition is complete, the temperature is increased to 55°C at a rate of 2°C / min, and stirred at this temperature for 3 hours. Once a non-flowing gel is observed to form, stirring is stopped, and the mixture is allowed to stand at 55°C for 2 hours. Then, the temperature is lowered to room temperature and aged for another 6 hours to ensure a complete cross-linking reaction.

[0127] Step A5: Post-processing;

[0128] Remove the gel, cut it into 5mm×5mm pieces, transfer it to a Buchner funnel, and sonicate it with deionized water at 200W for 15 minutes each time. Filter it three times to remove unreacted acetic acid.

[0129] Soak and wash twice with 0.5 mol / L sodium bicarbonate solution for 1.5 h each time to neutralize residual acid and prevent NaOH from damaging the nano-silver. Filter by suction.

[0130] Finally, the filtrate was ultrasonically washed with deionized water until the pH of the filtrate was 6.8±0.2, and the Schiff reagent test showed no aldehyde odor. The filtrate was then ready for use.

[0131] Step A6: Vacuum drying and molding;

[0132] The washed gel particles were transferred to a vacuum drying oven and dried at 45°C and 0.09 MPa for 10 hours until the particles reached a constant weight.

[0133] After drying, the resin is pulverized and passed through a 30-mesh sieve to obtain a light yellow powdery antibacterial resin.

[0134] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0135] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An antibacterial resin, characterized by, It is composed of the following components: chitosan 4-6 parts by mass, dilute acetic acid solution 300-600 parts by mass, nano-silver particles 0.05-0.15 parts by mass, thymol 0.2-0.4 parts by mass, anhydrous ethanol 3-5 parts by mass, β-cyclodextrin 0.7-0.9 parts by mass, glutaraldehyde 2-3 parts by mass, anhydrous citric acid 0.1-0.3 parts by mass, sodium bicarbonate 2-2.2 parts by mass, and deionized water 2100-2300 parts by mass.

2. The antimicrobial resin according to claim 1, characterized in that: The acetic acid in the dilute acetic acid solution accounts for 1-2%, and the volume fraction of the anhydrous ethanol is specifically 95%.

3. The antimicrobial resin according to claim 2, wherein It is composed of the following components: chitosan 4-6 parts by mass, dilute acetic acid solution 300-600 parts by mass, nano-silver particles 0.05-0.15 parts by mass, thymol 0.2-0.4 parts by mass, anhydrous ethanol 3-5 parts by mass, β-cyclodextrin 0.7-0.9 parts by mass, glutaraldehyde 2-3 parts by mass, anhydrous citric acid 0.1-0.3 parts by mass, sodium bicarbonate 2-2.2 parts by mass, and deionized water 2100-2300 parts by mass.

4. A method for preparing an antibacterial resin using chitosan, characterized by, It includes the following steps: Step A1, raw material pretreatment; Take chitosan, add nano-silver particles, grind in a mortar for 10 min, transfer to a vacuum drying oven, dry and sieve, to obtain a chitosan-nano-silver mixture; Step A2, preparation of a composite antibacterial chitosan solution; Weigh thymol, dissolve it in anhydrous ethanol, slowly drop it into deionized water containing β-cyclodextrin, magnetically stir for 1.5 h, and form a β-cyclodextrin-thymol inclusion solution; Add the pretreated chitosan-nano-silver mixture to a 1-2% dilute acetic acid solution, magnetically stir at room temperature for 3 h, after complete dissolution, pour it into the above-mentioned β-cyclodextrin-thymol inclusion solution, continue to stir for 1 h, and ultrasonically disperse for 15 min, to obtain a composite antibacterial chitosan solution; Step A3, preparation of a composite crosslinking agent solution; Take glutaraldehyde, dilute it with deionized water to 83 mL, its mass fraction is 3%, add anhydrous citric acid, magnetically stir for 30 min until completely dissolved, and reserve; Step A4, construction of a pre-reaction system; Transfer the composite antibacterial chitosan solution to a three-necked flask, start constant temperature magnetic stirring, the rotating speed is 300 r / min, the temperature is controlled at 35℃, according to the molar ratio of chitosan to glutaraldehyde 1:0.8, add the composite crosslinking agent solution to the composite antibacterial chitosan solution dropwise; After the dropwise addition is completed, increase the temperature to 55℃ at a rate of 2℃ / min, keep stirring for 3 h, after observing that the system forms a non-flowing gel, stop stirring; Step A5, post-treatment; Take out the gel, cut it into small pieces of 4mm×4mm-6mm×6mm, transfer it to a Buchner funnel, ultrasonically wash it with deionized water, the power is 200W, each time for 15 min, and extract it 3 times; Then use 0.5 mol / L sodium bicarbonate solution to soak and wash it 2 times, each time for 1.5 h, and extract it; Finally, ultrasonically wash it with deionized water until the filtrate pH=6.8±0.2, Schiff reagent detection has no aldehyde smell, and reserve it; Step A6, vacuum drying and molding; Transfer the washed gel particles to a vacuum drying oven, dry them under the conditions of 45℃ and 0.09 MPa for 10 h, until the particles reach a constant weight; After drying, crush them, sieve through a 30 mesh sieve, to obtain an antibacterial resin.

5. The method of claim 4, wherein the method is characterized by: The temperature of the vacuum drying oven in step A1 is set to 65 degrees Celsius, the vacuum pressure is 0.09 MPa, the drying time is 5 hours, and after drying, the product is sieved through a 90-mesh sieve.

6. The method of claim 4, wherein the method is characterized by: The magnetic stirring operation in step A2 is specifically a programmed temperature stirring operation, in which the initial stirring temperature is 25 degrees Celsius and the stirring time is 30 minutes, and then the temperature is raised to 35 degrees Celsius and the stirring time is 1 hour.

7. The method for preparing antibacterial resin using chitosan according to claim 4, characterized in that, Before adding the anhydrous citric acid in step A3, the anhydrous citric acid is pretreated as follows: The anhydrous citric acid is ground in a low-temperature cryogenic grinder (-10 degrees Celsius) for 10 minutes and sieved through a 100-mesh sieve to form a fine powder.

8. The method of claim 7, wherein the method is characterized by the steps of: The magnetic stirring operation in step A3 is as follows: 70% of the deionized water is measured and used to dissolve glutaraldehyde to a mass fraction of 3%, and then the citric acid fine powder is added, and the mixture is stirred at 25 degrees Celsius for 15 minutes; then the remaining 30% of the deionized water is added, and the temperature is raised to 30 degrees Celsius for further stirring for 15 minutes until complete dissolution.

9. The method for preparing antibacterial resin using chitosan according to claim 4, characterized in that: In step A4, the composite crosslinking agent solution is slowly added to the composite antibacterial chitosan solution at a rate of 1.5 drops per second, and the stirring process is continued for 1 hour during the addition process. The addition position of the composite crosslinking agent solution is the vortex center area formed by the stirrer.

10. A method for preparing antibacterial resin using chitosan according to claim 9, characterized in that: After the formation of the non-flowing gel in step A4, the temperature is maintained at 55 degrees Celsius for 2 hours of aging, and then the temperature is lowered to room temperature for further aging for 6 hours.