Antibacterial polypropylene composite material, preparation method thereof and medicine bottle

Abstract

The invention belongs to the technical field of high-performance polypropylene, and discloses an antibacterial polypropylene composite material, a preparation method thereof and a medicine bottle. The antibacterial polypropylene composite material is prepared from polypropylene, composite antibacterial particles, a lubricant and the like. Wherein the polypropylene accounts for 78-87.3%, the composite antibacterial particles account for 10-18%, the lubricant accounts for 1-2%, the antioxidant accounts for 0.5-2%, the flexibilizer accounts for 1-3%, and the nucleating agent accounts for 0.2-0.3%. The antibacterial polypropylene composite material disclosed by the invention has very high antibacterial property and mechanical property. The antibacterial polypropylene composite material not only has an antibacterial effect on common bacteria such as escherichia coli and staphylococcus aureus, but also has remarkable antibacterial activity on drug-resistant bacteria such as vancomycin-resistant enterococcus faecalis (VRE) and methicillin-resistant staphylococcus aureus (MRSA), and the outstanding antibacterial characteristic of the antibacterial polypropylene composite material is shown.

Description

Technical Field

[0001] The present invention belongs to the technical field of high-performance polypropylene, and more specifically, relates to an antibacterial polypropylene composite material, a preparation method thereof, and a medicine bottle. Background Art

[0002] Polypropylene (PP), a general-purpose thermoplastic resin, offers excellent chemical stability, corrosion resistance, and processability, making it widely used in packaging, automotive, electronics, and healthcare. In particular, PP is commonly used in the manufacture of disposable medical devices, infusion sets, surgical supplies, and pharmaceutical packaging. However, because PP lacks inherent antimicrobial properties, bacteria can easily grow on its surface in humid environments or during prolonged use, posing a risk of cross-infection and limiting its application in applications requiring high hygiene and safety standards. To improve the antimicrobial properties of PP, existing techniques typically employ the addition of antimicrobial agents through blending and modification. For example, silver ion-based antimicrobial agents and quaternary ammonium salt-based antimicrobial agents have been widely studied and applied. However, these antimicrobial agents are mostly polar substances, while PP itself is a non-polar polymer. The significant polarity difference between the two leads to poor dispersion of the antimicrobial agents in the matrix, poor compatibility, and weak interfacial bonding, which in turn affects the overall mechanical properties of the material.

[0003] At the same time, drug-resistant bacterial infections in healthcare settings have become a major challenge to global public health. Superbugs such as methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococci (VRE) are particularly susceptible to conventional antibiotics, significantly increasing the difficulty of clinical treatment. These resistant bacteria are frequently detected in high-risk areas of hospital infection, such as intensive care units, and their mortality rate is 2-3 times higher than that of common strains.

[0004] On the other hand, to improve the environmental performance of polypropylene, some studies have attempted to incorporate natural wood fibers (such as wood flour) as fillers into the polypropylene matrix to reduce raw material costs and enhance the material's biodegradability. However, the addition of wood flour also presents a series of problems. First, the interfacial compatibility between wood flour and polypropylene is poor, resulting in a decrease in the mechanical properties of the composite material. Second, wood flour contains a certain amount of organic components such as sugars and hemicellulose, which are prone to thermal degradation or microbial attack during processing and use. In turn, it may become a carrier for microbial reproduction, further exacerbating the material's health and safety risks. Therefore, how to effectively improve the antimicrobial and comprehensive mechanical properties of polypropylene without sacrificing its inherent excellent properties is one of the technical challenges that need to be addressed in current polypropylene material modification research. Summary of the Invention

[0005] In order to overcome the above-mentioned defects of the prior art, the present invention provides an antibacterial polypropylene composite material.

[0006] Another object of the present invention is to provide a method for preparing an antibacterial polypropylene composite material.

[0007] Another object of the present invention is to provide an antibacterial polypropylene medicine bottle.

[0008] In order to solve the above technical problems, the technical solutions of the present invention are as follows: An antibacterial polypropylene composite material is prepared from polypropylene, composite antibacterial particles, a lubricant, an antioxidant, a toughening agent, and a nucleating agent; wherein the mass percentage of polypropylene is 78%-87.3%, the mass percentage of the composite antibacterial particles is 10%-18%, the mass percentage of the lubricant is 1%-2%, the mass percentage of the antioxidant is 0.5%-2%, the mass percentage of the toughening agent is 1%-3%, and the mass percentage of the nucleating agent is 0.2%-0.3%.

[0009] Preferably, the polypropylene is homopolypropylene.

[0010] Preferably, the polypropylene melt mass flow rate is 1.8~2.0g / min, and the melt mass flow rate is measured in accordance with GB 3682.1-2018.

[0011] Preferably, the lubricant comprises one or more of oleamide, polyethylene wax, and calcium stearate.

[0012] Preferably, the antioxidant comprises one of phenols or phosphites.

[0013] Further preferably, the antioxidant is one of antioxidant 330 (1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene), antioxidant 168 (tris(2,4-di-tert-butylphenyl)phosphite) and antioxidant 1010 pentaerythritol tetrakis(3,5-di-tert-butyl-4-hydroxyhydrocinnamate).

[0014] Preferably, the toughening agent comprises one of high-density polyethylene or low-density polyethylene.

[0015] Preferably, the nucleating agent is a sorbitol nucleating agent.

[0016] More preferably, the nucleating agent is one of 1,3:2,4-di-p-methylbenzylidene sorbitol or 1,3:2,4-di(3,4-dimethylbenzylidene)-D-sorbitol.

[0017] Furthermore, the composite antibacterial particles are prepared by the following method: S1: adding wood powder into an acetoacetic acid modified solvent for pretreatment; then washing the treated wood powder with an ethanol aqueous solution, and then drying, thereby obtaining a pretreated powder.

[0018] S2: adding the obtained pretreated powder into a metal ion aqueous solution, soaking, filtering, and obtaining a mixture.

[0019] S3: placing the above mixture in a ball mill jar for ball milling; after the grinding is completed, the obtained material is rinsed and dried, and the part with a particle size of 200 mesh to 300 mesh is screened to obtain composite antibacterial particles.

[0020] Preferably, in step S1, the wood powder is selected from one or more of fir powder, pine powder, birch powder, bamboo powder and mixtures thereof.

[0021] Preferably, the wood powder is obtained by directly crushing logs, and the 30-60 mesh portion is selected through sieving.

[0022] Preferably, the lignin content in the wood powder is not less than 25%.

[0023] Preferably, the acetoacetic acid modified solvent in step S1 consists of an acetoacetic acid ester compound and a polar aprotic solvent.

[0024] Preferably, the mass ratio of the acetoacetic acid ester compound to the polar aprotic solvent in the acetoacetic acid modified solvent is 12 to 7:1, the pretreatment temperature is 100 to 130° C., and the pretreatment time is 4 to 6 hours.

[0025] Preferably, the mass ratio of the acetoacetic acid ester compound to the polar aprotic solvent in the acetoacetic acid modified solvent is 12:1.

[0026] Preferably, the acetoacetate compound comprises one or more of tert-butyl acetoacetate, ethyl acetoacetate and methyl acetoacetate.

[0027] Preferably, the acetoacetate compound is tert-butyl acetoacetate.

[0028] Preferably, the polar aprotic solvent comprises at least one of N,N-dimethylformamide and dimethyl sulfoxide.

[0029] Preferably, the polar aprotic solvent comprises N,N-dimethylformamide.

[0030] Preferably, the mass ratio of the wood powder to the acetoacetic acid modified solvent in step S1 is 1:10-15.

[0031] Preferably, the mass percentage of the ethanol aqueous solution in step S1 is not less than 30%.

[0032] In this invention, wood flour is treated with a mixed solvent containing acetoacetate groups to achieve surface modification. This process not only increases the surface area of the wood flour while preserving its natural structure, but also increases the number of active adsorption sites. This innovative approach improves the interfacial compatibility between wood flour and polypropylene (PP) while increasing the number of adsorption sites for antimicrobial ingredients.

[0033] In the present invention, the higher lignin content in the wood powder can effectively enhance the interfacial interaction between the wood powder and the polypropylene matrix while maintaining its structural stability, thereby improving the compatibility between the two.

[0034] Furthermore, the metal ion aqueous solution in step S2 contains gallium nitrate; or, the solution contains gallium nitrate and zinc chloride; or, the solution contains gallium nitrate and copper chloride.

[0035] Preferably, the mass percentage of gallium nitrate in the metal ion aqueous solution is 1% to 2%, the mass percentage of zinc chloride is 1% to 3%, and the mass percentage of copper chloride is 1% to 3%.

[0036] Preferably, the metal ion aqueous solution contains 2% by mass of gallium nitrate and 3% by mass of zinc chloride.

[0037] Preferably, the metal ion aqueous solution contains 2% by mass of gallium nitrate and 3% by mass of copper chloride.

[0038] Preferably, the metal ion aqueous solution contains 1% by mass of gallium nitrate and 3% by mass of zinc chloride.

[0039] Preferably, the metal ion aqueous solution contains 1% by mass of gallium nitrate and 3% by mass of copper chloride.

[0040] Preferably, the metal ion aqueous solution in step S2 is a gallium nitrate aqueous solution with a concentration of 1-2%.

[0041] Preferably, the soaking time in step S2 is not less than 1 hour.

[0042] Preferably, the grinding process conditions in step S3 are: the grinding speed is controlled between 300 and 600 rpm; and the grinding time is controlled between 30 and 45 minutes.

[0043] Preferably, the rinsing in step S3 uses an ethanol aqueous solution with a mass percentage of not less than 30%.

[0044] Preferably, the drying temperature in step S3 is controlled between 30 and 60 degrees Celsius.

[0045] In the present invention, the antibacterial composite particles are prepared by mechanochemical method, and multiple modification effects are achieved by ball milling process: during the ball milling process, the antibacterial active ions (such as Ga 3+ 、Ga 3+ / Zn 2+ 、Ga 3+ / Cu 2+ ) through mechanochemical action on the acetoacetate sites of acetoacetate-modified wood powder, further forming antimicrobial nanoclusters. Simultaneously, mechanical shear force fractures the cellulose microfibrils on the wood powder surface, exposing more acetoacetate-modified sites and significantly improving interfacial properties. Furthermore, by controlling ball milling parameters, the wood powder particle size is further refined to 200-300 mesh, achieving a good match with the polypropylene matrix. This method for preparing antimicrobial composite particles combines the triple functions of nanodispersion, surface activation, and particle size regulation, providing an effective approach for preparing high-performance antimicrobial composite materials.

[0046] In the present invention, gallium nitrate can achieve antibacterial effects when used alone. When gallium metal is used in combination with zinc metal or copper ions, the antibacterial effects of zinc metal or copper ions can be significantly enhanced.

[0047] A method for preparing an antibacterial polypropylene composite material comprises the following steps: Weigh polypropylene, lubricant, composite antibacterial particles, antioxidant, toughening agent, and nucleating agent according to the formula ratio. Mix the weighed polypropylene, lubricant, antioxidant, toughening agent, nucleating agent, and composite antibacterial particles and then place them into a twin-screw extruder for melt extrusion and granulation at 160-210°C to obtain an antibacterial polypropylene composite material.

[0048] An antibacterial polypropylene medicine bottle, the preparation method of which comprises the following steps: The antibacterial polypropylene composite material is plasticized at 160-190°C and then injection-molded into a blank. Finally, the blank is initially cooled and transferred to a blow molding station for blow molding and shaping. After cooling and demoulding, the antibacterial polypropylene medicine bottle is obtained.

[0049] Preferably, the injection mold temperature is controlled at 65°C.

[0050] Compared with the prior art, the beneficial effects of the technical solution of the present invention are: By introducing high-performance composite antibacterial particles into a polypropylene matrix, the resulting polypropylene composite material achieves a synergistic improvement in both antibacterial and mechanical properties. The antibacterial polypropylene composite material provided by the present invention exhibits significant antibacterial activity against drug-resistant strains, achieving an antibacterial rate of over 98% against common Escherichia coli ATCC25922 and Staphylococcus aureus ATCC6538. Testing also reveals antibacterial rates exceeding 97% against methicillin-resistant Staphylococcus aureus (MRSA, ATCC 43300) and vancomycin-resistant Enterococci (VRE, ATCC 51299), while also achieving a tensile strength of 28.1 MPa. This excellent antibacterial performance makes it particularly suitable for use in areas with a high risk of hospital-acquired infections, particularly medical settings prone to drug-resistant infections, such as intensive care units. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 This is a diagram of the antibacterial polypropylene composite material of Example 1. DETAILED DESCRIPTION

[0052] The present invention will be further described below in conjunction with the accompanying drawings and specific examples, but the examples do not limit the present invention in any form. Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the art.

[0053] Unless otherwise specified, all reagents and materials used in the following examples were commercially available.

[0054] The raw materials used in the examples and comparative examples are described below, but are not limited to these materials: Homopolymer polypropylene, PP PPH-T03-GD / Zhenhai Refining and Chemical, melt mass flow rate 1.9 g / min, isotactic index 97.1%.

[0055] Antioxidant 330 (1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene), 99%.

[0056] Antioxidant 168, tris(2,4-di-tert-butylphenyl) phosphite, 98%.

[0057] Antioxidant 1010, pentaerythritol tetrakis(3,5-di-tert-butyl-4-hydroxyhydrocinnamate), ≥98%.

[0058] High-density polyethylene, melt index (Melting Index): 12g / 10min (190℃ / 2.16kg).

[0059] Low density polyethylene, melt index (Melting Index): 70g / 10min, particle size: 600 mesh.

[0060] Nucleating agent 3988, 1,3:2,4-bis(3,4-dimethylbenzylidene)-D-sorbitol, 99%.

[0061] Transparent nucleating agent 3940, D823192 1,3:2,4-di-p-methylbenzylidene sorbitol, 98%.

[0062] Example 1

[0063] An antibacterial polypropylene composite material, the specific preparation steps are as follows: (1) Preparation of composite antibacterial particles Prepare 100 g of acetoacetic acid-modified solvent (tert-butyl acetoacetate:N,N-dimethylformamide) in a 9:1 mass ratio. Add 10 g of pine wood flour with a particle size of 30-60 mesh and a lignin content of 27% to 100 g of the modified solvent and treat at 120°C for 5 hours. After the reaction is complete, wash the wood flour with a 70% ethanol solution and dry it at 60°C to obtain a pretreated powder. Add 100 g of a 1% gallium nitrate solution to the pretreated powder and soak it at room temperature for 3 hours. Then filter the mixture to obtain the antibacterial composite particles. Place the mixture in a ball mill and grind it in a planetary ball mill at 500 rpm for 45 minutes. After grinding, rinse the resulting material with a 70% ethanol solution, filter it, and dry it at 50°C. Sieve the resulting fine powder with a particle size of 200-300 mesh to obtain the antibacterial composite particles.

[0064] (2) Preparation of antibacterial polypropylene composite materials According to the weight ratio, 87.3% homopolymer polypropylene, 1% calcium stearate, 10% composite antibacterial particles, 0.5% antioxidant 330, 1% high-density polyethylene, and 0.2% nucleating agent 3940 were mixed and then put into a twin-screw extruder for melt blending. The temperature of each section of the extruder was adjusted to: 160°C in zone 1, 170°C in zone 2, 190°C in zone 3, 200°C in zone 4, 210°C in zone 5, 210°C in zone 6, 210°C in zone 7, 200°C in zone 8, and 190°C in zone 9. The screw speed was 500 r / min, and the screw aspect ratio was 45:1. The material after melt blending was extruded through an extruder head and immediately entered a cooling device for cooling and shaping. It was then stretched by a traction device and made into granules through a cutting device to finally obtain an antibacterial polypropylene composite material.

[0065] (3) Preparation of antibacterial polypropylene bottles: The antibacterial polypropylene composite material is plasticized at 160-190°C, and then injection-molded into a blank, and the injection mold temperature is controlled at 65°C; finally, the blank is initially cooled and transferred to a blow molding station for blow molding and shaping, and the antibacterial polypropylene bottle is obtained after cooling and demolding.

[0066] Example 2

[0067] This embodiment provides an antibacterial polypropylene composite material and an antibacterial polypropylene medicine bottle. The specific preparation method of the antibacterial polypropylene composite material is different from that of Example 1 in that the mass ratio of tert-butyl acetoacetate to DMF in the acetoacetic acid modified solvent in step (1) is 12:1.

[0068] Example 3

[0069] This embodiment provides an antibacterial polypropylene composite material and an antibacterial polypropylene medicine bottle. The specific preparation method of the antibacterial polypropylene composite material is different from that of Example 1 in that the mass ratio of tert-butyl acetoacetate to DMF in the acetoacetic acid modified solvent in step (1) is 7:1.

[0070] Example 4

[0071] This embodiment provides an antibacterial polypropylene composite material and an antibacterial polypropylene medicine bottle. The specific preparation method of the antibacterial polypropylene composite material is different from that of Example 1 in that the preparation of the antibacterial polypropylene composite material in step (2) contains 83.3% homopolymer polypropylene, 1% polyethylene wax, 14% composite antibacterial particles, 0.5% antioxidant 330, 1% high-density polyethylene, and 0.2% nucleating agent 3940.

[0072] Example 5

[0073] This embodiment provides an antibacterial polypropylene composite material and an antibacterial polypropylene medicine bottle. The specific preparation method of the antibacterial polypropylene composite material is different from that of Example 1 in that the preparation of the antibacterial polypropylene composite material in step (2) contains 78.3% homopolymer polypropylene, 2% polyethylene wax, 18% composite antibacterial particles, 0.5% antioxidant 330, 1% high-density polyethylene, and 0.2% nucleating agent 3940.

[0074] Example 6

[0075] This embodiment provides an antibacterial polypropylene composite material and an antibacterial polypropylene medicine bottle. The specific preparation method of the antibacterial polypropylene composite material is different from that of Example 1 in that the preparation of the antibacterial polypropylene composite material in step (2) contains 87.3% homopolymer polypropylene, 1% polyethylene wax, 10% composite antibacterial particles, 0.5% antioxidant 330, 1% high-density polyethylene, and 0.2% nucleating agent 3940.

[0076] Example 7

[0077] This embodiment provides an antibacterial polypropylene composite material and an antibacterial polypropylene medicine bottle. The specific preparation method of the antibacterial polypropylene composite material is different from that of Example 1 in that the preparation of the antibacterial polypropylene composite material in step (2) contains 85.3% homopolymer polypropylene, 3% oleamide, 10% composite antibacterial particles, 0.5% antioxidant 330, 1% high-density polyethylene, and 0.2% nucleating agent 3940.

[0078] Example 8

[0079] This embodiment provides an antibacterial polypropylene composite material and an antibacterial polypropylene medicine bottle. The specific preparation method of the antibacterial polypropylene composite material is different from that of Example 1 in that in step (1), the obtained pretreated powder is added to 100 g of an aqueous solution with a mass percentage of 2% gallium nitrate and 3% zinc chloride, and the mixture is soaked at room temperature for 3 hours, and then washed with water and filtered to obtain a mixture.

[0080] Example 9

[0081] This embodiment provides an antibacterial polypropylene composite material and an antibacterial polypropylene medicine bottle. The specific preparation method of the antibacterial polypropylene composite material is different from that of Example 1 in that in step (1), the obtained pretreated powder is added to 100 g of an aqueous solution with a mass percentage of 2% gallium nitrate and 3% copper chloride, and the mixture is soaked at room temperature for 3 hours, and then washed with water and filtered to obtain a mixture.

[0082] Example 10

[0083] This embodiment provides an antibacterial polypropylene composite material and an antibacterial polypropylene medicine bottle. The specific preparation method of the antibacterial polypropylene composite material is different from that of Example 1 in that in step (1), the obtained pretreated powder is added to 100 g of an aqueous solution of 1% gallium nitrate and 3% copper chloride by mass, and the mixture is soaked at room temperature for 3 hours, and then washed with water and filtered to obtain a mixture.

[0084] Example 11

[0085] This embodiment provides an antibacterial polypropylene composite material and an antibacterial polypropylene medicine bottle. The specific preparation method of the antibacterial polypropylene composite material is different from that of Example 1 in that in step (1), the obtained pretreated powder is added to 100 g of an aqueous solution of 1% gallium nitrate and 3% copper chloride by mass, and the mixture is soaked at room temperature for 3 hours, and then washed with water and filtered to obtain a mixture.

[0086] Example 12

[0087] This embodiment provides an antibacterial polypropylene composite material and an antibacterial polypropylene medicine bottle. The specific preparation method of the antibacterial polypropylene composite material is different from that of Example 1 in that the non-polar protic solvent in the acetoacetic acid modified solvent in step (1) is dimethyl sulfoxide; and the mixture is ground in a planetary ball mill at a speed of 500 rpm for 30 minutes.

[0088] Example 13

[0089] This embodiment provides an antibacterial polypropylene composite material and an antibacterial polypropylene medicine bottle. The specific preparation method of the antibacterial polypropylene composite material is different from that of Example 1 in that step (2) is to mix 83.7% homopolymer polypropylene, 1% calcium stearate, 10% composite antibacterial particles, 2% antioxidant 168, 3% low-density polyethylene, and 0.3% nucleating agent 3988 according to the weight ratio, and then put them into a twin-screw extruder for melt blending.

[0090] Example 14

[0091] This embodiment provides an antibacterial polypropylene composite material and an antibacterial polypropylene medicine bottle. The specific preparation method of the antibacterial polypropylene composite material is different from that of Example 1 in that step (2) is to mix 83.7% homopolymer polypropylene, 1% calcium stearate, 10% composite antibacterial particles, 2% antioxidant 1010, 3% low-density polyethylene, and 0.3% nucleating agent 3988 according to the weight ratio, and then put them into a twin-screw extruder for melt blending.

[0092] Comparative Example 1 This embodiment provides an antibacterial polypropylene composite material and a polypropylene medicine bottle. The specific preparation method of the antibacterial polypropylene composite material is different from that of Example 1 in that no wood powder is added in the preparation of the antibacterial polypropylene composite material in step (2).

[0093] Comparative Example 2 This embodiment provides an antibacterial polypropylene composite material and a polypropylene medicine bottle. The specific preparation method of the antibacterial polypropylene composite material is different from that of Example 1 in that 10% 200-300 mesh natural wood powder is added in the preparation of the antibacterial polypropylene composite material in step (2).

[0094] Comparative Example 3 This embodiment provides an antibacterial polypropylene composite material and a polypropylene medicine bottle. The specific preparation method of the antibacterial polypropylene composite material is different from that of Example 1 in that the composite antibacterial particles in step (1) are not pretreated with acetoacetic acid.

[0095] Comparative Example 4 This embodiment provides an antibacterial polypropylene composite material and a polypropylene medicine bottle. The specific preparation method of the antibacterial polypropylene composite material is different from that of Example 1 in that gallium nitrate is not added in step (1). The obtained pretreated powder is added to 100 g of a 3% by mass zinc chloride aqueous solution, soaked at room temperature for 3 hours, and then washed with water and filtered to obtain a mixture.

[0096] Comparative Example 5 This embodiment provides an antibacterial polypropylene composite material and a polypropylene medicine bottle. The specific preparation method of the antibacterial polypropylene composite material is different from that of Example 1 in that gallium nitrate is not added in step (1). The obtained pretreated powder is added to 100 g of a 3% by mass copper chloride aqueous solution, soaked at room temperature for 3 hours, and then washed with water and filtered to obtain a mixture.

[0097] Comparative Example 6 This embodiment provides an antibacterial polypropylene composite material and a polypropylene medicine bottle. The specific preparation method of the antibacterial polypropylene composite material is different from that of Example 1 in that in step (1), the obtained pretreated powder is added to 100 g of an aqueous solution with a mass percentage of 0.01% gallium nitrate and 3% zinc chloride, and the mixture is soaked at room temperature for 3 hours, and then washed with water and filtered to obtain a mixture.

[0098] Comparative Example 7 This embodiment provides an antibacterial polypropylene composite material and a polypropylene medicine bottle. The specific preparation method of the antibacterial polypropylene composite material is different from that of Example 1 in that in step (1), the obtained pretreated powder is added to 100 g of an aqueous solution of 3% by mass of gallium nitrate and 3% by mass of zinc chloride, and the mixture is soaked at room temperature for 3 hours, and then washed with water and filtered to obtain a mixture.

[0099] Comparative Example 8 This embodiment provides an antibacterial polypropylene composite material and a polypropylene medicine bottle. The specific preparation method of the antibacterial polypropylene composite material is different from that of Example 1 in that step (1) screens antibacterial particles with a size of less than 200 mesh.

[0100] Comparative Example 9 This embodiment provides an antibacterial polypropylene composite material and a polypropylene medicine bottle. The specific preparation method of the antibacterial polypropylene composite material is different from that of Example 1 in that step (1) screens antibacterial particles larger than 300 mesh.

[0101] Comparative Example 10 This embodiment provides an antibacterial polypropylene composite material and a polypropylene medicine bottle. The specific preparation method of the antibacterial polypropylene composite material is different from that of Example 1 in that no lubricant is added in step (2).

[0102] Comparative Example 11 This embodiment provides an antibacterial polypropylene composite material and a polypropylene medicine bottle. The specific preparation method of the antibacterial polypropylene composite material is different from that of Example 1 in that 7% composite antibacterial particles are added in the preparation of the antibacterial polypropylene composite material in step (2).

[0103] Comparative Example 12 This embodiment provides an antibacterial polypropylene composite material and a polypropylene medicine bottle. The specific preparation method of the antibacterial polypropylene composite material is different from that of Example 1 in that 20% composite antibacterial particles are added in the preparation of the antibacterial polypropylene composite material in step (2).

[0104] Comparative Example 13 This embodiment provides an antibacterial polypropylene composite material and a polypropylene medicine bottle. The specific preparation method of the antibacterial polypropylene composite material is different from that of Example 1 in that step (1) uses wood powder with a lignin content of 23%.

[0105] Detection method: The lignin content was determined according to GB / T 2677.8-1994, "Determination of the Acid-Insoluble Lignin Content of Papermaking Raw Materials." The resulting antibacterial polypropylene material was pressed into plastic sheets of standard dimensions. Tensile properties were tested according to GB / T 1040.2-2006. Antibacterial properties were evaluated according to ISO 22196:2011, against Escherichia coli (ATCC 25922), Staphylococcus aureus (ATCC 6538), methicillin-resistant Staphylococcus aureus (MRSA) ATCC 43300, and vancomycin-resistant Enterococcus faecalis (VRE) ATCC 51299.

[0106] The results are shown in the table below: Table 1 Test results of antibacterial polypropylene materials

[0107] Results As shown in Table 1, the results from Examples 1 to 14 demonstrate that the present invention, by incorporating composite antimicrobial particles into a polypropylene matrix and using a specific type of lubricant, results in a material that exhibits excellent antimicrobial properties not only against Escherichia coli (ATCC 25922) and Staphylococcus aureus (ATCC 6538), but also against methicillin-resistant Staphylococcus aureus (MRSA, ATCC 43300) and vancomycin-resistant Enterococcus faecalis (VRE, ATCC 51922), with antimicrobial percentages exceeding 97%. Furthermore, the composite antimicrobial particles not only impart antimicrobial properties to the material but also synergistically enhance the tensile properties of the polypropylene matrix. Testing has shown that mechanical properties, such as tensile strength, have been significantly improved, reaching levels exceeding 28 MPa, resulting in excellent overall performance.

[0108] Comparative analysis of the test results from Example 1 and Comparative Examples 1-2 reveals that the antibacterial rates of the polypropylene material in Comparative Example 1, which lacks the composite antibacterial particles of the present invention, and the polypropylene material in Comparative Example 2, which incorporates wood powder without antibacterial modification, range from 10.1% to 15%. Although the wood powder content in Comparative Example 2 remains the same as in Example 1 (10 wt%), its tensile strength is lower than that of Example 1 due to the lack of antibacterial functionalization. In contrast, the antibacterial composite polypropylene material of the present invention exhibits superior overall performance, achieving an antibacterial rate exceeding 97% while maintaining excellent mechanical properties. Its tensile strength is 15.6% higher than that of Comparative Example 1 and 11.1% higher than that of the non-antibacterial modified wood powder in Comparative Example 2. This comparison demonstrates that the incorporation of the composite antibacterial particles in the present invention not only imparts antibacterial functionality to the material but also enhances its mechanical properties.

[0109] The test results of Examples 1-3 show that the concentration of tert-butyl acetoacetate in the pretreatment process is positively correlated with the antibacterial properties of the final product. When the mass ratio of tert-butyl acetoacetate to DMF is within the range of 7:1 to 12:1, the antibacterial rate of the product against Escherichia coli and Staphylococcus aureus reaches 99%, and the antibacterial rate against drug-resistant bacteria reaches 98%. In the preparation method of the composite antibacterial particles of the present invention, the surface modification treatment of acetoacetic acid plays an important role in improving the antibacterial effect. The test data of Comparative Example 3 show that in the sample without acetoacetic acid surface modification, the corresponding antibacterial performance is significantly reduced, and its antibacterial rate is only 23.3%-40.3%.

[0110] As shown in Examples 1, 8-11, and Comparative Examples 4-7, the use of specific gallium ions (Ga³⁺) as the antibacterial component in the metal salt solution plays a significant role in achieving the material's overall performance. Comparative Examples 4-5 show that when conventional zinc ions (Zn²⁺) or copper ions (Cu²⁺) are used instead, the product's antibacterial efficacy against common Escherichia coli ATCC 25922 and Staphylococcus aureus ATCC 6538 drops to 91.5-94.1%, while its antibacterial efficacy against drug-resistant strains (MRSA and VRE) is significantly less than 50%. Comparative Examples 6-7 show that the material performance is optimal when the gallium ion concentration is in the range of 1-2%. A concentration below 1% results in a decrease in antibacterial performance. The product has an antibacterial rate of 92.8-94.1% against common Escherichia coli ATCC 25922 and Staphylococcus aureus ATCC 6538, and an antibacterial rate of less than 50% against drug-resistant strains (MRSA and VRE). When the concentration exceeds 2%, the mechanical properties drop to 23.5 MPa.

[0111] As shown in Example 1 and Comparative Examples 8-9, the particle size range of the composite antibacterial particles has an impact on the performance of the polypropylene composite material. When using composite antibacterial particles with a mesh size of 200-300, the material exhibits the optimal combination of comprehensive properties: the tensile strength reaches 28.1 MPa, and the antibacterial rate remains above 97%. Comparative Examples 8-9 show that when the particle size exceeds this optimal range, the material performance decreases significantly: in Comparative Example 8, composite antibacterial particles with a mesh size less than 200 lead to a 27.1% decrease in tensile strength and a decrease in antibacterial performance to 90.6-93.1%; while in Comparative Example 9, composite antibacterial particles with a mesh size greater than 300 lead to a 20% decrease in tensile strength, and the antibacterial performance against drug-resistant bacteria is even lower than that in the 200-300 mesh range, falling to 95.3%-96.1%. These data fully demonstrate that controlling the particle size of the composite antibacterial particles within the 200-300 mesh range is an important technical feature for achieving an optimal balance between antibacterial and mechanical properties.

[0112] As can be seen from Example 1, Examples 6-7 and Comparative Example 10, when the present invention does not use a lubricant, the mechanical properties of the material decrease significantly by only 21.1 MPa, indicating that the lubricant of the present invention plays an important role in improving the interface compatibility of the composite material.

[0113] The test data from Example 1, Examples 4-5, and Comparative Examples 11-12 show a significant correlation between the content of the composite antimicrobial particles in the polypropylene matrix and the material's performance. When the composite antimicrobial particle content was controlled within the range of 10-18 wt%, the material's antimicrobial performance significantly improved with increasing antimicrobial particle content. In Comparative Example 11, when the composite antimicrobial particle content was less than 10 wt%, the material's antimicrobial performance significantly decreased, with an antimicrobial rate below 95%. In Comparative Example 12, when the composite antimicrobial particle content exceeded 18 wt%, while the antimicrobial rate remained above 98%, the material's mechanical properties declined compared to Example 1, with the tensile strength decreasing by approximately 15.7%.

[0114] It can be seen from Example 1 and Comparative Example 13 that the lignin content in the raw materials of the present invention affects the product performance. The antibacterial and mechanical properties of the wood powder product with a lignin content of less than 23% are reduced, the tensile performance decreases by about 17.8%, and the antibacterial rate decreases to 87.1%-92.1%.

[0115] The above embodiments are merely examples for the purpose of clearly illustrating the present invention and are not intended to limit the embodiments of the present invention. Those skilled in the art will appreciate that other variations or modifications may be made based on the above description. It is not necessary and impossible to enumerate all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention are intended to be included within the scope of protection of the claims of the present invention.

Claims

1. An antibacterial polypropylene composite material, characterized in that: The invention is prepared from polypropylene, composite antibacterial particles, lubricant, antioxidant, toughening agent and nucleating agent; wherein the mass percentage of polypropylene is 78%-87.3%, the mass percentage of composite antibacterial particles is 10%-18%, the mass percentage of lubricant is 1%-2%, the mass percentage of antioxidant is 0.5%-2%, the mass percentage of toughening agent is 1%-3%, and the mass percentage of nucleating agent is 0.2%-0.3%.

2. The antibacterial polypropylene composite material according to claim 1, characterized in that: The composite antibacterial particles are prepared by the following method: S1: adding wood powder to an acetoacetic acid modified solvent for pretreatment; then washing the treated wood powder with an ethanol aqueous solution, and then drying to obtain a pretreated powder; S2: adding the obtained pretreated powder into a metal ion aqueous solution, soaking, and filtering to obtain a mixture; S3: placing the above mixture in a ball mill jar for ball milling; after the grinding is completed, the obtained material is rinsed and dried, and the particle size of the part with a diameter of 200-300 mesh is selected through screening to obtain composite antibacterial particles; The acetoacetic acid modified solvent consists of an acetoacetic acid ester compound and a polar aprotic solvent; The polar aprotic solvent comprises at least one of N,N-dimethylformamide and dimethyl sulfoxide.

3. The antibacterial polypropylene composite material according to claim 2, characterized in that: The lignin content in the wood powder in step S1 is not less than 25%.

4. The antibacterial polypropylene composite material according to claim 2, characterized in that: The acetoacetate ester compound includes one or more of tert-butyl acetoacetate, ethyl acetoacetate and methyl acetoacetate.

5. The antibacterial polypropylene composite material according to claim 2, characterized in that: The mass ratio of the acetoacetate compound to the polar aprotic solvent in step S1 is 12 to 7:

1.

6. The antibacterial polypropylene composite material according to claim 2, characterized in that: The metal ion aqueous solution contains gallium nitrate; or, the solution contains gallium nitrate and zinc chloride; or, the solution contains gallium nitrate and copper chloride.

7. The antibacterial polypropylene composite material according to claim 6, characterized in that: The mass percentage of gallium nitrate in the metal ion aqueous solution is 1% to 2%, the mass percentage of zinc chloride is 1% to 3%, and the mass percentage of copper chloride is 1% to 3%.

8. The antibacterial polypropylene composite material according to claim 2, characterized in that: The mass ratio of the wood powder to the acetoacetic acid modified solvent in step S1 is 1:10-15.

9. A method for preparing the antibacterial polypropylene composite material according to any one of claims 1 to 8, characterized in that: The following steps are involved: Polypropylene, lubricant, composite antibacterial particles, antioxidant, toughening agent, and nucleating agent are weighed according to the formula ratio; the weighed polypropylene, lubricant, antioxidant, toughening agent, nucleating agent, and composite antibacterial particles are mixed and put into a twin-screw extruder, and melt-extruded and granulated at 160-210° C. to obtain an antibacterial polypropylene composite material.

10. An antibacterial polypropylene medicine bottle, characterized in that: The preparation method comprises the following steps: The antibacterial polypropylene composite material according to any one of claims 1 to 8 is plasticized at 160-190° C., and then injection-molded into a blank; finally, the blank is initially cooled and transferred to a blow molding station for blow molding and shaping, and the antibacterial polypropylene medicine bottle is obtained after cooling and demoulding.

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