High-strength antibacterial polypropylene composite material and preparation method thereof

Abstract

The application relates to the technical field of polypropylene composite materials, and discloses a high-strength antibacterial polypropylene composite material and a preparation method.The polypropylene composite material comprises 60-90 parts by weight of polypropylene, 10-40 parts by weight of nylon 6, 2-8 parts by weight of maleic anhydride grafted polypropylene, 0.5-2 parts by weight of arginine antibacterial agent and the like.The arginine antibacterial agent has good compatibility with the polypropylene and the nylon 6, is uniformly dispersed in the composite material, has little influence on the mechanical properties of the material, and can maintain high tensile strength and impact strength.The side chain of the arginine antibacterial agent contains a large number of guanidine antibacterial groups, has good heat resistance, is not prone to thermal decomposition, is uniformly dispersed in the composite material matrix, effectively kills staphylococcus aureus and escherichia coli, and makes the composite material have strong antibacterial performance.

Description

Technical Field

[0001] This invention relates to the field of polypropylene composite material technology, specifically to a high-strength antibacterial polypropylene composite material and its preparation method. Background Technology

[0002] Antibacterial materials mainly include antibacterial plastics, antibacterial coatings, and antibacterial fibers. They are typically created by incorporating antibacterial agents into polymeric materials, imparting excellent antibacterial properties. Traditional antibacterial agents include inorganic agents such as nano-titanium dioxide; and organic antibacterial agents such as quaternary ammonium salts, guanidines, and amino acids. Organic antibacterial agents offer advantages such as diverse preparation methods and broad-spectrum antibacterial activity. Compared to small-molecule compound antibacterial agents, macromolecular polymer antibacterial agents have better heat resistance, are less prone to thermal decomposition, and have a wider range of applications.

[0003] Polypropylene is lightweight, chemically stable, electrically insulating, and easy to process and mold, making it widely used in kitchen utensils, plastic containers, packaging materials, automobiles, building materials, and medical devices. However, its poor antibacterial properties limit its practical applications. Chinese patent CN117487304B discloses an antibacterial masterbatch based on guanidine salt polymers and its preparation method. Using polyethylene, polypropylene, modified guanidine salt polymers, polydimethylsiloxane, and hydrogenated C6-14 olefin polymers as raw materials, the prepared antibacterial masterbatch exhibits good antibacterial properties, but it does not demonstrate good mechanical strength. Summary of the Invention

[0004] This invention solves the problem of poor antibacterial properties of polypropylene nylon composite materials.

[0005] The technical solution of the present invention is: a high-strength antibacterial polypropylene composite material and its preparation method, wherein the composite material comprises 60-90 parts by weight of polypropylene, 10-40 parts by weight of nylon 6, 2-8 parts by weight of maleic anhydride grafted polypropylene, 0.5-2 parts by weight of arginine antibacterial agent, and 0.3-0.6 parts by weight of antioxidant.

[0006] The preparation method includes: mixing polypropylene, nylon 6, maleic anhydride-grafted polypropylene, arginine antibacterial agent, and antioxidant, and then melt-blending and extruding them in a twin-screw extruder. The temperature in zones one to five is 180-245℃, the screw speed is 100-200 r / min, and the mixture is pelletized to obtain a high-strength antibacterial polypropylene composite material.

[0007] Furthermore, the antioxidant is 1010 or antioxidant 168.

[0008] Furthermore, the preparation method of arginine antibacterial agent is as follows:

[0009] (1) Add N,N-dimethylformamide, BOC-L-arginine, ethylenediamine, O-benzotriazole-tetramethylurea hexafluorophosphate, 1-hydroxybenzotriazole, and N,N-diisopropylethylamine to a flask. Stir the reaction at 20-30°C for 7-10 h under a nitrogen atmosphere. Add ethyl acetate, extract and wash with sodium carbonate aqueous solution, dry the organic layer of ethyl acetate with anhydrous magnesium sulfate, filter, heat and evaporate the filtrate, cool and crystallize, recrystallize and purify to obtain the BOC precursor.

[0010] (2) Add ethyl acetate solution of HCl (HCl·EtOAc) and BOC precursor to the flask, stir the reaction at 20-30℃ for 3-5h, extract and wash with sodium carbonate aqueous solution, dry the organic layer of ethyl acetate with anhydrous magnesium sulfate, filter and evaporate the filtrate by rotary evaporation, add the product to ethanol aqueous solution, heat to evaporate, cool to crystallize, recrystallize and purify to obtain diaminoarginine.

[0011] The reaction formula is:

[0012]

[0013] (3) Add ethanol, diaminoarginine, and glutaraldehyde to a flask equipped with a reflux condenser, stir to allow the reaction to proceed, add water and dropwise hydrochloric acid solution, heat to evaporate, cool to crystallize, filter, wash with ethanol, and dry to obtain the arginine antibacterial agent. The reaction formula is:

[0014]

[0015] Furthermore, in (1), the molar ratio of BOC-L-arginine, ethylenediamine, O-benzotriazole-tetramethylurea hexafluorophosphate, 1-hydroxybenzotriazole, and N,N-diisopropylethylamine is (2.2-2.4):1:(2.4-2.6):(3.6-4.8):(4-6).

[0016] Furthermore, in (2), the concentration of the ethyl acetate solution of HCl is 4-5 mol / L.

[0017] Furthermore, in (3), the molar ratio of diaminoarginine to glutaraldehyde is (1.02-1.06):1.

[0018] Furthermore, (3) the reaction temperature is 55-65℃ and the reaction time is 5-8h.

[0019] Furthermore, (3) add hydrochloric acid solution to adjust the pH of the reaction solution to 5-6.

[0020] The beneficial technical effects of this invention are as follows: By performing an amidation reaction between BOC-L-arginine and ethylenediamine, followed by removal of the BOC protecting group in an ethyl acetate solution of HCl, a diaminoarginine containing amide bonds is obtained. This is then subjected to Schiff base polymerization with glutaraldehyde to obtain an amino-terminated arginine antibacterial agent. Finally, this agent is melt-blended with polypropylene, nylon, and maleic anhydride-grafted polypropylene to obtain a high-strength antibacterial polypropylene composite material. This antibacterial agent contains amino-terminated groups, allowing it to react with maleic anhydride-grafted polypropylene, thereby improving the compatibility between the arginine antibacterial agent and polypropylene. Furthermore, the main chain of the arginine antibacterial agent contains the same amide bonds as nylon 6, resulting in good compatibility between the antibacterial agent and nylon 6. This ensures that the arginine antibacterial agent is uniformly dispersed in the composite material, with minimal impact on the material's mechanical properties. The composite material maintains high tensile and impact strength.

[0021] The arginine antibacterial agent of the present invention has a large number of guanidine antibacterial groups in its side chain. At the same time, the arginine antibacterial agent is a macromolecular polymer with good heat resistance. During the high-temperature melt blending extrusion process, the antibacterial agent is not easily thermally decomposed. Furthermore, the arginine antibacterial agent is uniformly dispersed in the composite matrix, thereby effectively killing Staphylococcus aureus and Escherichia coli, giving the composite material strong antibacterial properties. Detailed Implementation

[0022] To facilitate understanding of the present invention, it will be described in more detail below. However, it should be understood that the present invention can be implemented in many different forms and is not limited to the embodiments or examples described herein. Rather, these embodiments or examples are provided to make the disclosure of the present invention more thorough and complete.

[0023] The following maleic anhydride-grafted polypropylene model ZJ-900P is from Guangzhou Zhongjie New Materials Co., Ltd.

[0024] Example 1

[0025] (1) Add 300 mL of N,N-dimethylformamide, 110 mmol of BOC-L-arginine, 50 mmol of ethylenediamine, 120 mmol of O-benzotriazole-tetramethylurea hexafluorophosphate, 240 mmol of 1-hydroxybenzotriazole, and 300 mmol of N,N-diisopropylethylamine to a flask. Stir the mixture at 20 °C for 10 h under a nitrogen atmosphere. Add ethyl acetate and extract and wash with sodium carbonate aqueous solution. Dry the organic layer of ethyl acetate with anhydrous magnesium sulfate. After filtration, heat the filtrate to evaporate and cool to crystallize, thus obtaining the BOC precursor.

[0026] (2) Add 600 mL of ethyl acetate solution with a concentration of 5 mol / L HCl and 40 g of BOC precursor to a flask, stir the reaction at 30 °C for 3 h, extract and wash with sodium carbonate aqueous solution, dry the organic layer of ethyl acetate with anhydrous magnesium sulfate, filter and evaporate the filtrate by rotary evaporation, add the product to an ethanol aqueous solution, heat to evaporate, cool and crystallize to obtain diaminoarginine.

[0027] (3) Add 180 mL of ethanol, 52 mmol of diaminoarginine and 50 mmol of glutaraldehyde to a flask equipped with a reflux condenser. Stir the reaction at 55 °C for 8 h. Add water and dropwise add 10% hydrochloric acid solution to adjust the pH to 6. Heat to evaporate, cool to crystallize, filter, wash with ethanol, and dry to obtain arginine antibacterial agent.

[0028] (4) Mix 9 kg of polypropylene, 1 kg of nylon 6, 0.2 kg of maleic anhydride-grafted polypropylene, 50 g of arginine antibacterial agent, and 60 g of antioxidant 168, and melt-blend and extrude them in a twin-screw extruder. The temperatures of zones one to five are 180℃, 200℃, 235℃, 245℃, and 240℃, and the screw speed is 150 r / min. The mixture is then pelletized to obtain a high-strength antibacterial polypropylene composite material.

[0029] Comparative Example 1

[0030] (1) Mix 9kg of polypropylene, 1kg of nylon 6 and 60g of antioxidant 168, and melt-blend extrude in a twin-screw extruder. The temperatures of zones one to five are 180℃, 200℃, 235℃, 245℃ and 240℃, and the screw speed is 150r / min. The mixture is then pelletized to obtain a polypropylene composite material.

[0031] Comparative Example 2

[0032] (1) Mix 9kg of polypropylene, 1kg of nylon 6, 50g of arginine antibacterial agent and 60g of antioxidant 168, and melt-blend and extrude in a twin-screw extruder. The temperatures of zones one to five are 180℃, 200℃, 235℃, 245℃ and 240℃, and the screw speed is 150r / min. The mixture is then pelletized to obtain a polypropylene composite material.

[0033] Comparative Example 3

[0034] (1) Mix 9 kg of polypropylene, 1 kg of nylon 6, 0.2 kg of maleic anhydride-grafted polypropylene and 60 g of antioxidant 168, and melt-blend and extrude in a twin-screw extruder. The temperatures of zones one to five are 180℃, 200℃, 235℃, 245℃ and 240℃, and the screw speed is 150 r / min. The mixture is then pelletized to obtain a polypropylene composite material.

[0035] Comparative Example 4

[0036] (1) Mix 9 kg of polypropylene, 1 kg of nylon 6, 0.2 kg of maleic anhydride-grafted polypropylene, 50 g of L-arginine, and 60 g of antioxidant 168, and melt-blend and extrude them in a twin-screw extruder. The temperatures of zones one to five are 180℃, 200℃, 235℃, 245℃, and 240℃, and the screw speed is 150 r / min. The mixture is then pelletized to obtain a polypropylene composite material.

[0037] Comparative Example 5

[0038] (1) Add 180 mL of ethanol, 52 mmol of 1,6-hexanediamine and 50 mmol of glutaraldehyde to a flask equipped with a reflux condenser. Stir the mixture at 55 °C for 8 h. Remove the ethanol by rotary evaporation, wash with petroleum ether, and dry to obtain the Schiff base polymer.

[0039] (2) Mix 9 kg of polypropylene, 1 kg of nylon 6, 0.2 kg of maleic anhydride-grafted polypropylene, 50 g of Schiff base polymer and 60 g of antioxidant 168, and melt-blend and extrude in a twin-screw extruder. The temperatures of zones one to five are 180℃, 200℃, 235℃, 245℃ and 240℃, and the screw speed is 150 r / min. The mixture is then pelletized to obtain a polypropylene composite material.

[0040] Example 2

[0041] (1) Add 350 mL of N,N-dimethylformamide, 120 mmol of BOC-L-arginine, 50 mmol of ethylenediamine, 130 mmol of O-benzotriazole-tetramethylurea hexafluorophosphate, 180 mmol of 1-hydroxybenzotriazole, and 200 mmol of N,N-diisopropylethylamine to a flask. Stir the mixture at 30 °C for 7 h under a nitrogen atmosphere. Add ethyl acetate and extract and wash the mixture with sodium carbonate aqueous solution. Dry the organic layer of ethyl acetate with anhydrous magnesium sulfate. After filtration, heat the filtrate to evaporate it and cool to crystallize, thus obtaining the BOC precursor.

[0042] (2) Add 800 mL of ethyl acetate solution with a concentration of 4 mol / L HCl and 40 g of BOC precursor to a flask, stir the reaction at 20 °C for 5 h, extract and wash with sodium carbonate aqueous solution, dry the organic layer of ethyl acetate with anhydrous magnesium sulfate, filter and evaporate the filtrate by rotary evaporation, add the product to an ethanol aqueous solution, heat to evaporate, cool and crystallize to obtain diaminoarginine.

[0043] (3) Add 180 mL of ethanol, 51 mmol of diaminoarginine and 50 mmol of glutaraldehyde to a flask equipped with a reflux condenser. Stir the reaction at 65 °C for 5 h. Add water and dropwise add 15% hydrochloric acid solution to adjust the pH to 6. Heat to evaporate, cool to crystallize, filter, wash with ethanol, and dry to obtain arginine antibacterial agent.

[0044] (4) Mix 7.5 kg of polypropylene, 2.5 kg of nylon 6, 0.5 kg of maleic anhydride-grafted polypropylene, 120 g of arginine antibacterial agent, and 50 g of antioxidant 1010, and melt-blend and extrude them in a twin-screw extruder. The temperatures of zones one to five are 180℃, 200℃, 235℃, 245℃, and 240℃, and the screw speed is 200 r / min. The mixture is then pelletized to obtain a high-strength antibacterial polypropylene composite material.

[0045] Example 3

[0046] (1) Add 200 mL of ethanol, 53 mmol of diaminoarginine (prepared from Example 1), and 50 mmol of glutaraldehyde to a flask equipped with a reflux condenser. Stir the mixture at 65 °C for 6 h. Add water and dropwise add 15% hydrochloric acid solution to adjust the pH to 5. Heat to evaporate, cool to crystallize, filter, wash with ethanol, and dry to obtain arginine antibacterial agent.

[0047] (2) Mix 6 kg of polypropylene, 4 kg of nylon 6, 0.8 kg of maleic anhydride-grafted polypropylene, 200 g of arginine antibacterial agent, and 30 g of antioxidant 168, and melt-blend and extrude them in a twin-screw extruder. The temperatures of zones one to five are 180℃, 200℃, 235℃, 245℃, and 240℃, and the screw speed is 100 r / min. The mixture is then pelletized to obtain a high-strength antibacterial polypropylene composite material.

[0048] Polypropylene composite materials were injection molded using an injection molding machine at temperatures of 215℃, 240℃, and 240℃ in zones one to three, with a pressure of 60MPa, to produce specimens. Tensile strength was tested according to GB / T 1040.1-2018 standard. Impact strength was tested according to GB / T 1843-2008 standard.

[0049] Table 1 Mechanical property testing of polypropylene composites

[0050] Tensile strength (MPa) <![CDATA[Impact strength (kJ / m 2 )]]> Example 1 37.1 7.80 Comparative Example 1 34.8 7.17 Comparative Example 2 32.5 6.63 Comparative Example 3 37.6 7.89 Comparative Example 4 37.3 7.84 Comparative Example 5 36.5 7.66 Example 2 41.6 8.92 Example 3 43.8 8.60

[0051] After testing, the tensile strength of Comparative Example 1 was 34.8 MPa, and the impact strength was 7.17 kJ / m. 2 Compared with Comparative Example 1, Comparative Example 2 added arginine antibacterial agent, which has poor compatibility with polypropylene and will affect the mechanical properties of the composite material, resulting in a decrease in tensile strength of (34.8-32.5)÷34.8×100%=6.61% and a decrease in impact strength of (7.17-6.63)÷7.17×100%=7.53%.

[0052] The tensile strength of Comparative Example 3 was 37.6 MPa, and the impact strength was 7.89 kJ / m. 2Compared with Comparative Example 3, Example 1, which added arginine antibacterial agent, showed a decrease in tensile strength of only (37.6-37.1)÷37.6×100%=1.33% and an decrease in impact strength of only (7.89-7.80)÷7.89×100%=2.37%. This is mainly because the antibacterial agent contains terminal amino groups, which can react with maleic anhydride-grafted polypropylene, making the maleic anhydride-grafted polypropylene act as a compatibilizer and improving the compatibility between the arginine antibacterial agent and polypropylene. Furthermore, the main chain of the arginine antibacterial agent contains the same amide bonds as nylon 6, which also makes the antibacterial agent and nylon 6 have good compatibility. As a result, the arginine antibacterial agent is uniformly dispersed in the composite material, with minimal impact on the mechanical properties of the material.

[0053] Comparative Example 5 uses 1,6-hexanediamine and glutaraldehyde to carry out Schiff base polymerization. The resulting polymer does not contain amide bonds and has poor compatibility with nylon 6, which has a certain impact on the mechanical properties of the composite material, resulting in lower tensile strength and impact strength than in Example 1.

[0054] The antibacterial properties of the composite material were tested according to QB / T 2591-2003 standard, with the composite material of Comparative Example 1 used as a blank control sample. Antibacterial rate = (BC) / B × 100%. B is the average recovered bacterial count of the blank control sample, CFU / tablet. C is the average recovered bacterial count of the antibacterial plastic sample, CFU / tablet.

[0055]

[0056] After testing, it was found that the composite materials in Examples 1-3 contained arginine antibacterial agent, whose molecular side chain contained a large number of guanidine antibacterial groups. At the same time, the arginine antibacterial agent is a macromolecular polymer with good heat resistance. During the high-temperature melt blending extrusion process, the antibacterial agent is not easily thermally decomposed. In addition, maleic anhydride grafted polypropylene compatibilizer was added to make the arginine antibacterial agent uniformly dispersed in the composite matrix, thereby effectively killing Staphylococcus aureus and Escherichia coli, giving the composite material a strong antibacterial property.

[0057] Comparative Example 2 did not include maleic anhydride-grafted polypropylene compatibilizer. The arginine antibacterial agent had poor compatibility with polypropylene and poor dispersion in the composite matrix, resulting in lower antibacterial performance of the composite material compared to Example 1.

[0058] Comparative Example 3 did not contain arginine antibacterial agent, and the composite material had very poor antibacterial properties.

[0059] The L-arginine added in Comparative Example 4 is a small molecule compound with poor heat resistance. It is prone to thermal decomposition during high-temperature melt blending and extrusion, resulting in a significantly lower antibacterial rate of the composite material compared to Example 1.

[0060] The Schiff base polymer in Comparative Example 5 does not contain guanidine antibacterial groups, and the composite material has very poor antibacterial properties.

[0061] The above are merely preferred embodiments of the present invention; however, the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and its improved concept, should be covered within the scope of protection of the present invention.

Claims

1. A high-strength antibacterial polypropylene composite material, characterized in that, The polypropylene composite comprises 60-90 parts by weight of polypropylene, 10-40 parts by weight of nylon 6, 2-8 parts by weight of maleic anhydride grafted polypropylene, 0.5-2 parts by weight of arginine antibacterial agent, and 0.3-0.6 parts by weight of antioxidant; The preparation method of the arginine antibacterial agent comprises the following steps: adding ethanol, diamino arginine with a molar ratio of (1.02-1.06):1 and glutaraldehyde into a flask provided with a condensation reflux pipe, stirring to react, adding water and dropwise adding hydrochloric acid solution, heating and evaporating, cooling and crystallizing, filtering and washing with ethanol, and drying to obtain the arginine antibacterial agent; The bis-amino arginine has a structural formula of .

2. The high-strength antibacterial polypropylene composite material according to claim 1, characterized in that, The antioxidant is 1010 or antioxidant 168.

3. The high-strength antibacterial polypropylene composite material according to claim 1, characterized in that, The temperature of the reaction is 55-65℃, and the reaction time is 5-8h.

4. The high-strength antibacterial polypropylene composite material according to claim 1, characterized in that, The dropwise adding of the hydrochloric acid solution adjusts the pH of the reaction solution to 5-6.

5. The high-strength antibacterial polypropylene composite material according to claim 1, characterized in that, The preparation method of the diamino arginine comprises the following steps: (1) adding N,N-dimethylformamide, BOC-L-arginine, ethylenediamine, O-benzotriazol-tetramethylurea hexafluorophosphate, 1-hydroxybenzotriazole and N,N-diisopropylethylamine into a flask, stirring to react at 20-30℃ for 7-10h, extracting, recrystallizing and purifying to obtain a BOC precursor; (2) adding a hydrochloric acid ethyl acetate solution and the BOC precursor into a flask, stirring to react at 20-30℃ for 3-5h, extracting, recrystallizing and purifying to obtain diamino arginine.

6. The high-strength antibacterial polypropylene composite material according to claim 5, characterized in that, The molar ratio of BOC-L-arginine, ethylenediamine, O-benzotriazol-tetramethylurea hexafluorophosphate, 1-hydroxybenzotriazole and N,N-diisopropylethylamine in (1) is (2.2-2.4):1:(2.4-2.6):(3.6-4.8):(4-6).

7. The high-strength antibacterial polypropylene composite material according to claim 5, characterized in that, The concentration of the hydrochloric acid ethyl acetate solution in (2) is 4-5mol / L.

8. A process for the preparation of a high-strength antibacterial polypropylene composite material as claimed in any one of claims 1 to 7, characterized in that, The preparation method comprises the following steps: mixing polypropylene, nylon 6, maleic anhydride grafted polypropylene, arginine antibacterial agent and antioxidant, melt blending and extruding in a double-screw extruder, and cutting into particles to obtain the high-strength antibacterial polypropylene composite.

9. The method for preparing the high-strength antibacterial polypropylene composite material according to claim 8, characterized in that, The temperature of the first to fifth zones of the double-screw extruder is 180-245℃, and the screw rotation speed is 100-200r / min.

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