Composite antibacterial agent suitable for children products, antibacterial ABS (Acrylonitrile Butadiene Styrene) resin and preparation method of antibacterial ABS resin

Abstract

The invention relates to the technical field of antibacterial agents, and particularly discloses a composite antibacterial agent suitable for children products, antibacterial ABS resin and a preparation method of the antibacterial ABS resin. The invention discloses a composite antibacterial agent for children products. The composite antibacterial agent is prepared from the following raw materials in parts by weight: 30-50 parts of modified nano chitosan quaternary ammonium salt, 10-30 parts of nano titanium dioxide, 5-10 parts of antibacterial peptide, 3-5 parts of ascorbic acid and 5-7 parts of polyvinylpyrrolidone. The modified nano chitosan quaternary ammonium salt is prepared by modifying a silane coupling agent. The antibacterial ABS resin prepared by adopting the composite antibacterial agent prepared by the invention has the highest bacteriostasis rates of 99.99% and 99.99% on staphylococcus aureus and escherichia coli, and the antibacterial property of the antibacterial ABS resin is improved. Therefore, when the composite antibacterial agent prepared by the invention is added into the common resin for the children products, the antibacterial property of the children products can be improved.

Description

Technical Field

[0001] The present application relates to the field of antibacterial agents, and more specifically, to a composite antibacterial agent applicable to children's products, an antibacterial ABS resin, and a preparation method thereof. Background Art

[0002] With the rapid development of the children's product market, plastic products are widely used in toys, tableware, stationery and other fields due to their light weight, durability and easy processing characteristics. However, traditional ABS resin materials themselves do not have antibacterial properties, and are prone to breed bacteria, molds and other microorganisms after long-term use, becoming a potential risk source threatening children's health. Especially, children's immune systems are not fully developed, and frequent contact with contaminated plastic products may cause skin infections, respiratory diseases and even cross-infection problems.

[0003] Globally, the demand for products with "antibacterial + environmental protection" dual attributes by consumers is growing rapidly. Children's products need to meet strict safety standards, including non-toxic, non-irritating, chew-resistant, etc. Traditional antibacterial agents may release harmful substances during high-temperature processing or long-term use, such as organic solvent residues or heavy metal precipitation, which do not meet the environmental protection and health requirements of children's products. In addition, children's toys and products will be used outdoors and need to be cleaned, posing a higher challenge to the long-term antibacterial performance of the materials.

[0004] Therefore, the research and development of composite antibacterial agents and antibacterial ABS resins applicable to children's products is an industrial demand for the deep integration of materials science, health needs and environmental protection concepts. Solving the defects of traditional antibacterial agents through technological innovation not only provides a safer growth environment for children, but also promotes the upgrading of the plastic industry towards high performance, multi-function and sustainability, injecting continuous impetus into children's health and industry development. Summary of the Invention

[0005] In order to improve the antibacterial property of children's products, the present application provides a composite antibacterial agent applicable to children's products, a preparation method and an application thereof.

[0006] In a first aspect, the present application provides a composite antibacterial agent applicable to children's products, which adopts the following technical solution: A composite antibacterial agent applicable to children's products, comprising the following raw materials in parts by weight: 30-50 parts of modified nano chitosan quaternary ammonium salt, 10-30 parts of nano titanium dioxide, 5-10 parts of antibacterial peptide, 3-5 parts of ascorbic acid, 5-7 parts of polyvinylpyrrolidone; the modified nano chitosan quaternary ammonium salt is prepared by modification with a silane coupling agent.

[0007] The raw materials of the composite antibacterial agent applicable to children's products include 30-50 parts of modified nano chitosan quaternary ammonium salt, 10-30 parts of nano titanium dioxide, 5-10 parts of antibacterial peptide, 3-5 parts of ascorbic acid, and 5-7 parts of polyvinylpyrrolidone. Any value within their respective ranges can be selected, and all can improve the antibacterial property of children's products to varying degrees.

[0008] By adopting the above technical solution, the nano chitosan quaternary ammonium salt is positively charged, and the bacterial cell membrane is negatively charged, which can adsorb and damage the bacterial cell membrane, inhibiting the growth of bacteria on the surface of children's products. Nano titanium dioxide can destroy the cell membrane and DNA of bacteria through photocatalysis, and nano titanium dioxide can physically adsorb bacteria, increasing its contact area with bacteria, and further killing bacteria. Moreover, nano titanium dioxide is a non-releasing antibacterial component with a long-term stable antibacterial effect. The modified nano chitosan quaternary ammonium salt is a releasing antibacterial component, which binds to the microbial cell membrane by releasing quaternary ammonium cations, destroys its structure, and causes bacteria to die. The dual action mechanism can enhance the antibacterial property of children's products. Therefore, the selection of the composite use of modified nano chitosan quaternary ammonium salt and nano titanium dioxide can further improve the antibacterial effect of the composite antibacterial agent, thereby enhancing the antibacterial property of children's products.

[0009] The antibacterial peptide acts on the negative charge of the microbial cell membrane through positive charge, destroys the cell membrane structure, thereby playing a bactericidal role, and the antibacterial peptide can stably exist in children's products, providing a long-term antibacterial effect. Moreover, nano titanium dioxide can enhance the dispersibility and stability of the antibacterial peptide in children's products. Ascorbic acid can protect the antibacterial peptide from oxidative degradation during the subsequent high-temperature process, and can also improve the activity of the antibacterial peptide, thereby enhancing the antibacterial effect of the antibacterial peptide.

[0010] Secondly, polyvinylpyrrolidone is a water-soluble polymer compound with low toxicity and safety. Adding polyvinylpyrrolidone to the composite antibacterial agent can improve the interfacial compatibility between raw materials such as modified nano chitosan quaternary ammonium salt and nano titanium dioxide, ensure the uniformity and stability of the composite antibacterial agent, improve the dispersibility of the composite antibacterial agent in the raw materials of children's products, and prevent the migration of the composite antibacterial agent, thereby further enhancing the antibacterial property of children's products.

[0011] In addition, the nano chitosan quaternary ammonium salt is modified by a silane coupling agent. On the one hand, it can prevent the loss or degradation of the nano chitosan quaternary ammonium salt, enable the nano chitosan quaternary ammonium salt to maintain long-term antibacterial activity, form a stable chemical structure, and extend the antibacterial effect; on the other hand, using a silane coupling agent to modify the nano chitosan quaternary ammonium salt can also improve the dispersion effect of the nano chitosan quaternary ammonium salt among other raw materials of the composite antibacterial agent, enhance the interfacial binding force between the nano chitosan quaternary ammonium salt and common resins such as the main raw material ABS resin of children's products, thereby enhancing the antibacterial property of children's products.

[0012] Preferably: A composite antibacterial agent suitable for children's products, which comprises the following raw materials in parts by weight: 35-45 parts of modified nano-chitosan quaternary ammonium salt, 15-25 parts of nano-titanium dioxide, 7-9 parts of antibacterial peptide, 3.5-4.5 parts of ascorbic acid, and 5.5-6.5 parts of polyvinylpyrrolidone.

[0013] The composite antibacterial agent suitable for children's products in this application selects 35-45 parts of modified nano-chitosan quaternary ammonium salt, 15-25 parts of nano-titanium dioxide, 7-9 parts of antibacterial peptide, 3.5-4.5 parts of ascorbic acid, and 5.5-6.5 parts of polyvinylpyrrolidone. Any value within their respective ranges can be selected, and it can improve the antibacterial property of children's products.

[0014] Preferably: The weight ratio of the nano-titanium dioxide to the modified nano-chitosan quaternary ammonium salt is 1:(2-4).

[0015] By adopting the above scheme, adjusting the weight ratio of the nano-titanium dioxide to the modified nano-chitosan quaternary ammonium salt can further improve the antibacterial effect of the composite antibacterial agent, thereby improving the antibacterial property of children's products, and further improving the antibacterial property of children's products.

[0016] Preferably: The specific modification method of the modified nano-chitosan quaternary ammonium salt is as follows: S1. Add nano-chitosan quaternary ammonium salt to 1% acetic acid solution and stir to dissolve to obtain a nano-chitosan quaternary ammonium salt solution; S2. Add a silane coupling agent and a composite catalyst to water in sequence and stir to obtain a mixed solution; S3. Add the mixed solution to the nano-chitosan quaternary ammonium salt solution and stir, heat to 60-80 °C and react for 2-4 h, adjust the pH to 4-6, precipitate, wash, and dry to obtain the modified nano-chitosan quaternary ammonium salt; The composite catalyst in step S2 is a composite of 2% acetic acid and 1% ammonia water.

[0017] Among them, the mass ratio of the nano-chitosan quaternary ammonium salt to the volume of deionized water is 1:(0.5-1.5); the volume ratio of the silane coupling agent to the mass of the nano-chitosan quaternary ammonium salt is 1:(5-10); the volume ratio of the silane coupling agent to water is 1:(3-5); the volume ratio of the composite catalyst to the silane coupling agent is 1:(0.01-0.02).

[0018] By adopting the above scheme, during the modification process, a composite catalyst composed of acetic acid and ammonia water is used. Acetic acid can accelerate the hydrolysis of the silane coupling agent, and ammonia water promotes condensation. The two are used in combination, which can improve the reaction efficiency, improve the dispersibility and interfacial bonding force of the nano-chitosan quaternary ammonium salt, and further improve the antibacterial property of children's products.

[0019] Preferably, the volume ratio of acetic acid to ammonia water is 1:(1 - 1.5).

[0020] By adopting the above technical solution, adjusting the volume ratio of acetic acid to ammonia water can further improve the reaction efficiency of the modified nano-chitosan quaternary ammonium salt, further improve the dispersibility and interfacial binding force of the nano-chitosan quaternary ammonium salt, and thus further improve the antibacterial property of children's products.

[0021] Preferably, the composite antibacterial agent applicable to children's products further comprises the following raw materials in parts by weight: 3.5 - 5 parts of polyethylene glycol.

[0022] By adopting the above technical solution, adding polyethylene glycol, the ether oxygen atoms of polyethylene glycol form a hydrogen bond network with the carbonyl group of polyvinylpyrrolidone, which can further enhance the interfacial binding force and dispersibility of the modified nano-chitosan quaternary ammonium salt and nano-titanium dioxide, and thus further improve the antibacterial property of children's products.

[0023] Preferably, the weight ratio of polyethylene glycol to polyvinylpyrrolidone is 1:(1 - 2).

[0024] By adopting the above technical solution, adjusting the weight ratio of polyethylene glycol to polyvinylpyrrolidone can further improve the interfacial binding force and dispersibility of the modified nano-chitosan quaternary ammonium salt and nano-titanium dioxide, and thus further improve the antibacterial property of children's products.

[0025] In the second aspect, the present application provides a preparation method of the composite antibacterial agent applicable to children's products as described in any one of the above, which is specifically realized through the following technical solutions: A preparation method of a composite antibacterial agent applicable to children's products, which comprises the following operating steps: Mix all the raw materials evenly to obtain a composite antibacterial agent applicable to children's products.

[0026] In the third aspect, the present application provides an antibacterial ABS resin containing the composite antibacterial agent applicable to children's products as described in any one of the above.

[0027] In the fourth aspect, the present application provides a preparation method of the above antibacterial ABS resin, which is specifically realized through the following technical solutions: A preparation method of an antibacterial ABS resin, which comprises the following operating steps: drying the ABS resin at 80 - 90 °C for 3 - 4 h, adding the composite antibacterial agent applicable to children's products as described in any one of claims 1 - 6, melting and blending, and extruding and pelletizing to obtain the antibacterial ABS resin; The dosage of the composite antibacterial agent is 3 - 5% of the dosage of the antibacterial ABS resin raw materials.

[0028] By adopting the above technical solution, ABS resin is a common thermoplastic with good mechanical strength, dimensional stability and easy processability, and is widely used in the production of children's products. Adding the composite antibacterial agent prepared in this application to the ABS resin endows the ABS resin with a high antibacterial effect.

[0029] In addition, the composite antibacterial agent obtained in this application is not limited to being applied to antibacterial ABS resin, and can also be added to common resins for children's products such as PC resin, PP resin, epoxy resin, and PET resin.

[0030] In summary, this application includes at least one of the following beneficial technical effects: (1) By controlling the types and dosages of raw materials of the composite antibacterial agent applicable to children's products, the antibacterial rates of the antibacterial ABS resin added with the composite antibacterial agent against Staphylococcus aureus and Escherichia coli are 99.94%-99.95% and 99.93%-99.94% respectively, improving the antibacterial property of the antibacterial ABS resin.

[0031] (2) By modifying nano-chitosan quaternary ammonium salt and adjusting the volume ratio of acetic acid to ammonia water, the antibacterial rates of the antibacterial ABS resin added with the composite antibacterial agent against Staphylococcus aureus and Escherichia coli are 99.97%-99.98% and 99.96%-99.98% respectively, further improving the antibacterial property of the antibacterial ABS resin.

[0032] (3) By adding polyethylene glycol to the raw materials of the composite antibacterial agent applicable to children's products and adjusting the weight ratio of polyethylene glycol to polyvinylpyrrolidone, the antibacterial rates of the antibacterial ABS resin added with the composite antibacterial agent against Staphylococcus aureus and Escherichia coli are 99.99% and 99.99% respectively, further improving the antibacterial property of the antibacterial ABS resin. Detailed implementation manners

[0033] The following further elaborates on this application with specific embodiments. The following raw materials in this application are all commercially available products. To fully disclose the raw materials of this application, it should not be construed as a limitation on the source of the raw materials. Specifically: nano-chitosan quaternary ammonium salt with a substitution degree of 40% and particle sizes of 25μm and 50nm; nano-titanium dioxide with a particle size of 30nm; antibacterial peptide with an effective substance content of 99%; ascorbic acid with an effective substance content of 99.8%; polyvinylpyrrolidone with an effective substance content of 99%; silane coupling agent with the model KH550; polyethylene glycol with an effective substance content of 98%.

[0034] The following is a preparation example of modified nano-chitosan quaternary ammonium salt: Preparation example 1 The modified nano chitosan quaternary ammonium salt of Preparation Example 1 was obtained through the following steps: S1. Add 1 Kg of nano chitosan quaternary ammonium salt to 1 L of deionized water and stir to dissolve to obtain a nano chitosan quaternary ammonium salt solution; S2. Add 143 mL of silane coupling agent and 4 g of composite catalyst to 572 mL of water in sequence and stir to obtain a mixed solution; S3. Add the mixed solution to the nano chitosan quaternary ammonium salt solution, stir, heat to 70 °C and react for 3 h, adjust the pH to 5, precipitate, wash, and dry at 50 °C for 12 h to obtain the modified nano chitosan quaternary ammonium salt.

[0035] Among them, the composite catalyst includes 2.67 g of 2% acetic acid and 1.33 g of 1% ammonia water.

[0036] Preparation Examples 2-5 The preparation methods of the modified nano chitosan quaternary ammonium salts in Preparation Examples 2-5 are the same as that of Preparation Example 1 and the types of raw materials are the same. The difference lies in that the dosages of 2% acetic acid and 1% ammonia water are 2 g and 2 g, 1.82 g and 2.18 g, 1.6 g and 2.4 g, 2.22 g and 1.78 g respectively, and the dosages of the remaining raw materials are the same as those in Preparation Example 1.

[0037] Example 1 The composite antibacterial agent applicable to children's products in Example 1 was prepared through the following steps: According to the dosages in Table 1, mix the modified nano chitosan quaternary ammonium salt, nano titanium dioxide and other raw materials evenly to obtain the composite antibacterial agent applicable to children's products.

[0038] Among them, the modified nano chitosan quaternary ammonium salt selected is the one prepared in Preparation Example 1.

[0039] Examples 2-5 The composite antibacterial agents applicable to children's products in Examples 2-5 are exactly the same as that of Example 1 in terms of preparation method and types of raw materials. The difference lies in the different dosages of the modified nano chitosan quaternary ammonium salt and nano titanium dioxide. For details, see Table 1.

[0040] Table 1 Dosages of each raw material of the composite antibacterial agents applicable to children's products in Examples 1-5 (kg) Examples 6-10 The composite antibacterial agents applicable to children's products in Examples 6-10 are exactly the same as that of Example 3 in terms of preparation method, types of raw materials and dosages. The difference lies in that the modified nano chitosan quaternary ammonium salts prepared in Preparation Examples 2-5 are selected respectively, and the dosages of the remaining raw materials are the same as those in Example 1.

[0041] Examples 11-15 The composite antibacterial agents for children's products in Examples 11 - 15 are exactly the same as those in Example 8 in terms of the preparation method and the types and dosages of raw materials, except that 5.4 kg, 6 kg, 4 kg, 3 kg, and 2.7 kg of polyethylene glycol are respectively added to the raw materials of the composite antibacterial agents.

[0042] Comparative Example 1 The composite antibacterial agent for children's products in Comparative Example 1 has the same preparation method as that in Example 1, except that the modified nano - chitosan quaternary ammonium salt in the raw materials of the composite antibacterial agent is replaced with nano - chitosan quaternary ammonium salt in equal amount, and the other raw materials and their dosages are the same as those in Example 1.

[0043] Comparative Example 2 The composite antibacterial agent for children's products in Comparative Example 2 has the same preparation method as that in Example 1, except that the modified nano - chitosan quaternary ammonium salt in the raw materials of the composite antibacterial agent is replaced with modified quaternary ammonium salt chitosan in equal amount. The preparation method of the modified quaternary ammonium salt chitosan is the same as that of the modified nano - chitosan quaternary ammonium salt, only replacing 50 nm of quaternary ammonium salt chitosan with 25 μm of quaternary ammonium salt chitosan in equal amount, and the other raw materials and their dosages are the same as those in Example 1.

[0044] Comparative Example 3 The composite antibacterial agent for children's products in Comparative Example 3 has the same preparation method as that in Example 1, except that the polyvinylpyrrolidone in the raw materials of the composite antibacterial agent is replaced with zinc stearate in equal amount, and the other raw materials and their dosages are the same as those in Example 1.

[0045] Among them, zinc stearate has a particle size of 75 μm and an active substance content of 99%.

[0046] Comparative Example 4 The composite antibacterial agent for children's products in Comparative Example 4 has the same preparation method as that in Example 1, except that the modified nano - chitosan quaternary ammonium salt in the raw materials of the composite antibacterial agent is replaced with nano - titanium dioxide in equal amount, and the types and dosages of the other raw materials are the same as those in Example 1.

[0047] Comparative Example 5 The composite antibacterial agent for children's products in Comparative Example 5 has the same preparation method as that in Example 1, except that the nano - titanium dioxide in the raw materials of the composite antibacterial agent is replaced with modified nano - chitosan quaternary ammonium salt in equal amount, and the types and dosages of the other raw materials are the same as those in Example 1.

[0048] The following are the application examples of the composite antibacterial agent for children's products in antibacterial ABS resin: Application Example 1 First, 1 kg of ABS resin was dried at 85 °C for 3 h, then 40 g of the composite antibacterial agent prepared in Example 1 and applicable to children's products was added for melt blending, and extrusion granulation was carried out at 220 °C and 350 r / min, and then dried in a constant temperature oven at 90 °C for 5 h to obtain antibacterial ABS resin.

[0049] Application Example 2 - 15 The preparation method of the antibacterial ABS resin in Application Example 2 - 15 is exactly the same as that in Application Example 1, the difference is that the composite antibacterial agent obtained in Examples 2 - 15 and applicable to children's products is selected, and the raw material dosage is the same as that in Application Example 1.

[0050] Application Comparative Example 1 - 5 The preparation method of the antibacterial ABS resin in Application Comparative Example 1 - 5 is exactly the same as that in Application Example 1, the difference is that the composite antibacterial agent obtained in Comparative Examples 1 - 5 and applicable to children's products is selected, and the raw material dosage is the same as that in Application Example 1.

[0051] Performance Detection The antibacterial ABS resins obtained in different Application Examples 1 - 15 and Application Comparative Examples 1 - 5 were respectively subjected to performance detection using the following detection standards or methods, and the detection results are shown in Table 2.

[0052] Tensile strength: The tensile strength of the antibacterial ABS resin was detected using GB / T 1040 - 2018 "Determination of Tensile Properties of Plastics".

[0053] Flexural strength: The flexural strength of the antibacterial ABS resin was detected using GB / T 9341 - 2008 "Determination of Flexural Properties of Plastics".

[0054] Flexural modulus: The flexural modulus of the antibacterial ABS resin was detected using GB / T 9341 - 2008 "Determination of Flexural Properties of Plastics".

[0055] Bacteriostatic rate: Using QB / T 2591 - 2003A "Test Methods for Antibacterial Properties and Antibacterial Effects of Antibacterial Plastics", the bacteriostatic rates of the antibacterial ABS resin against Staphylococcus aureus and Escherichia coli were detected.

[0056] Table 2 Performance Detection Results of Antibacterial ABS Resin The test results in Table 2 show that the highest flexural modulus, flexural strength, and tensile strength of the antibacterial ABS resin obtained in this application are 2.7 GPa, 89.5 MPa, and 52.9 MPa respectively, indicating high mechanical properties. Moreover, the antibacterial rates of the antibacterial ABS resin prepared with the composite antibacterial agent obtained in this application against Staphylococcus aureus and Escherichia coli are 99.99% and 99.99% respectively, improving the antibacterial property of the antibacterial ABS resin. It can be seen that adding the composite antibacterial agent obtained in this application to the commonly used resins for children's products can improve the antibacterial property of children's products.

[0057] In Application Examples 1 - 5, the antibacterial rates of the antibacterial ABS resins in Application Examples 2 - 4 against Staphylococcus aureus and Escherichia coli are 99.94% - 99.95% and 99.93% - 99.94% respectively, both higher than those in Application Example 1 and Application Example 5. This indicates that the weight ratio of nano-titanium dioxide to modified nano-chitosan quaternary ammonium salt of 1:(2 - 4) is more appropriate, improving the antibacterial property of the antibacterial ABS resin.

[0058] In Application Examples 6 - 10, the antibacterial rates of the antibacterial ABS resins in Application Examples 7 - 9 against Staphylococcus aureus and Escherichia coli are 99.97% - 99.98% and 99.96% - 99.98% respectively, both higher than those in Application Example 6 and Application Example 10. This indicates that when modifying nano-chitosan quaternary ammonium salt, the volume ratio of acetic acid to ammonia water of 1:(1 - 1.5) is more appropriate, improving the antibacterial property of the antibacterial ABS resin.

[0059] In Application Examples 11 - 15, the antibacterial rates of the antibacterial ABS resins in Application Examples 12 - 14 against Staphylococcus aureus and Escherichia coli are 99.99 and 99.99% respectively, both higher than those in Application Example 11 and Application Example 15. This indicates that the weight ratio of polyethylene glycol to polyvinylpyrrolidone of 1:(1 - 2) is more appropriate, improving the antibacterial property of the antibacterial ABS resin.

[0060] In addition, by combining and analyzing the various index data of the antibacterial ABS resins in Application Comparative Examples 1 - 5 and Application Example 1, it is found that adding modified nano-chitosan quaternary ammonium salt, nano-titanium dioxide, and polyvinylpyrrolidone to the PA plastic raw material in this application can all improve the antibacterial property of the antibacterial ABS resin to varying degrees.

[0061] This specific embodiment is only an explanation of this application and does not limit this application. After reading this specification, those skilled in the art can make modifications to this embodiment without creative contributions as needed, but as long as it is within the scope of the claims of this application, it is protected by the patent law.

Claims

1. A composite antibacterial agent suitable for children's products, characterized in that: The invention comprises the following raw materials in parts by weight: 30-50 parts of modified nano-chitosan quaternary ammonium salt, 10-30 parts of nano-titanium dioxide, 5-10 parts of antimicrobial peptide, 3-5 parts of ascorbic acid and 5-7 parts of polyvinyl pyrrolidone; the modified nano-chitosan quaternary ammonium salt is prepared by modification with a silane coupling agent.

2. The composite antibacterial agent suitable for children's products according to claim 1, characterized in that: The invention comprises the following raw materials in parts by weight: 35-45 parts of modified nano-chitosan quaternary ammonium salt, 15-25 parts of nano-titanium dioxide, 7-9 parts of antimicrobial peptide, 3.5-4.5 parts of ascorbic acid and 5.5-6.5 parts of polyvinyl pyrrolidone.

3. The composite antibacterial agent suitable for children's products according to claim 1, characterized in that: The weight ratio of the nano titanium dioxide to the modified nano chitosan quaternary ammonium salt is 1:(2-4).

4. The composite antibacterial agent suitable for children's products according to claim 1, characterized in that: The specific modification method of the modified nano-chitosan quaternary ammonium salt is: S1, adding nano-chitosan quaternary ammonium salt to deionized water and stirring to dissolve, to obtain a nano-chitosan quaternary ammonium salt solution; S2, adding the silane coupling agent and the composite catalyst to water in sequence and stirring to obtain a mixed solution; S3, adding the mixed solution to the nano-chitosan quaternary ammonium salt solution and stirring, heating to 60-80°C for reaction for 2-4h, adjusting the pH to 4-6, precipitating, washing, and drying to obtain modified nano-chitosan quaternary ammonium salt; The composite catalyst in step S2 is a composite of 2% acetic acid and 1% ammonia water.

5. The composite antibacterial agent suitable for children's products according to claim 4, characterized in that: The volume ratio of the acetic acid to the ammonia water is 1:(1-1.5).

6. The composite antibacterial agent suitable for children's products according to claim 1, characterized in that: The composite antibacterial agent suitable for children's products further comprises the following raw materials in parts by weight: 3.5-5 parts of polyethylene glycol.

7. The composite antibacterial agent suitable for children's products according to claim 6, characterized in that: The weight ratio of the polyethylene glycol to the polyvinyl pyrrolidone is 1:(1-2).

8. A method for preparing the composite antibacterial agent suitable for children's products according to any one of claims 1 to 7, characterized in that: The method comprises the following steps: mixing the raw materials uniformly to obtain a composite antibacterial agent suitable for children's products.

9. An antibacterial ABS resin comprising the composite antibacterial agent suitable for children's products according to any one of claims 1 to 7.

10. A method for preparing the antibacterial ABS resin according to claim 9, characterized in that: The method comprises the following steps: first drying the ABS resin at 80-90° C. for 3-4 hours, then adding the composite antibacterial agent suitable for children's products according to any one of claims 1-7, melt blending, extruding granulation, and drying to obtain the antibacterial ABS resin; The dosage of the composite antibacterial agent is 3-5% of the dosage of the antibacterial ABS resin raw material.

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