High-strength antibacterial polypropylene composite material and preparation method thereof

Abstract

The invention relates to the technical field of polypropylene composite materials, and discloses a high-strength antibacterial polypropylene composite material and a preparation method thereof, 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 an arginine antibacterial agent and the like. The arginine antibacterial agent has good compatibility with polypropylene and nylon 6, is uniformly dispersed in the composite material, has little influence on the mechanical properties of the material, and can maintain very high tensile strength and impact strength. A side chain of the arginine antibacterial agent contains a large number of guanidyl antibacterial groups, and the arginine antibacterial agent is good in heat resistance, not prone to thermal decomposition, uniformly dispersed in a composite material matrix and capable of effectively killing staphylococcus aureus and escherichia coli, so that the composite material has very high antibacterial performance.

Description

Technical Field

[0001] The present invention relates to the technical field of polypropylene composite materials, and specifically relates to a high-strength antibacterial polypropylene composite material and a preparation method thereof. Background Art

[0002] Antibacterial materials mainly include antibacterial plastics, antibacterial coatings, antibacterial fibers, etc. Usually, antibacterial agents are added to polymer materials to endow the materials with good antibacterial properties. Traditional antibacterial agents include inorganic antibacterial agents such as nano-titanium dioxide; organic antibacterial agents such as quaternary ammonium salts, guanidines, and amino acids. Organic antibacterial agents have certain advantages such as diverse preparation methods and good antibacterial broad-spectrum properties. Compared with small molecule compound antibacterial agents, macromolecular polymer antibacterial agents have better heat resistance, are not easily thermally decomposed, and are more widely used.

[0003] Polypropylene is light in weight, high in chemical stability, good in electrical insulation, and easy to process and form. It is widely used in kitchen utensils, plastic containers, packaging materials, automobiles, building materials, medical devices and other aspects. However, the poor antibacterial performance of polypropylene limits its actual application fields. Chinese Patent CN117487304B discloses an antibacterial masterbatch based on guanidine salt polymer and its preparation method. Using polyethylene, polypropylene, modified guanidine salt polymer, polydimethylsiloxane, hydrogenated C6-14 olefin polymer, etc. as raw materials, the prepared antibacterial masterbatch has good antibacterial performance, but this antibacterial masterbatch does not show good mechanical strength. Summary of the Invention

[0004] The present invention solves the problem of poor antibacterial performance of polypropylene nylon composites.

[0005] The technical solution of the present invention is: a high-strength antibacterial polypropylene composite material and a preparation method thereof. The composite material includes 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 performing melt blending and extrusion in a twin-screw extruder. The temperature of the first to fifth zones is 180-245 °C, the screw speed is 100-200 r / min, and pelletizing is carried out to obtain the high-strength antibacterial polypropylene composite material.

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

[0008] Further, the preparation method of the arginine antibacterial agent is:

[0009] (1) Add N,N-dimethylformamide, BOC-L-arginine, ethylenediamine, O-benzotriazol-1-yl-N,N,N',N'-tetramethyluronium hexafluorophosphate, 1-hydroxybenzotriazole, and N,N-diisopropylethylamine to a flask. Stir and react at 20 - 30 °C for 7 - 10 h under a nitrogen atmosphere. Add ethyl acetate, extract and wash with an aqueous sodium carbonate solution. Dry the ethyl acetate organic layer with anhydrous magnesium sulfate, filter, and then heat and evaporate the filtrate. Cool and crystallize, and purify by recrystallization to obtain the BOC precursor.

[0010] (2) Add an ethyl acetate solution of HCl (HCl·EtOAc) and the BOC precursor to a flask. Stir and react at 20 - 30 °C for 3 - 5 h. Extract and wash with an aqueous sodium carbonate solution. Dry the ethyl acetate organic layer with anhydrous magnesium sulfate, filter, and then rotary evaporate the filtrate. Add the product to an ethanol aqueous solution, heat and evaporate, cool and crystallize, and purify by recrystallization to obtain diaminol-arginine.

[0011] The reaction formula is:

[0012]

[0013] (3) Add ethanol, diaminol-arginine, and glutaraldehyde to a flask equipped with a condenser reflux tube. Stir to react, add water and dropwise add a hydrochloric acid solution. Heat and evaporate, cool and 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-benzotriazol-1-yl-N,N,N',N'-tetramethyluronium 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 diaminol-arginine to glutaraldehyde is (1.02 - 1.06):1.

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

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

[0020] Advantageous technical effects of the present invention: By subjecting BOC-L-arginine and ethylenediamine to an amidation reaction, then removing the BOC protecting group in an ethyl acetate solution of HCl, a diaminoarginine containing an amide bond is obtained. Then, a Schiff base polymerization reaction is carried out with glutaraldehyde to obtain an arginine antibacterial agent with terminal amino groups. Finally, it is melt-blended with polypropylene, nylon, and maleic anhydride-grafted polypropylene to obtain a high-strength antibacterial polypropylene composite material. This antibacterial agent contains terminal amino groups and can react with maleic anhydride-grafted polypropylene, thereby improving the compatibility between the arginine antibacterial agent and polypropylene. Moreover, the main chain of the arginine antibacterial agent contains the same amide bond as nylon 6, making the antibacterial agent also have good compatibility with nylon 6. As a result, the arginine antibacterial agent is evenly dispersed in the composite material, has little impact on the mechanical properties of the material, and the composite material can maintain high tensile strength and impact strength.

[0021] The side chain of the arginine antibacterial agent of the present invention contains 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 and extrusion process, the antibacterial agent is not easily thermally decomposed, and the arginine antibacterial agent is evenly dispersed in the composite material matrix, thereby effectively killing Staphylococcus aureus and Escherichia coli and making the composite material have strong antibacterial properties. Specific embodiments

[0022] To facilitate the understanding of the present invention, the present invention 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. On the contrary, the purpose of providing these embodiments or examples is to make the understanding of the disclosure content of the present invention more thorough and comprehensive.

[0023] The following maleic anhydride-grafted polypropylene model ZJ-900P is sourced 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-benzotriazol-1-yl-N,N,N',N'-tetramethyluronium hexafluorophosphate, 240 mmol of 1-hydroxybenzotriazole, and 300 mmol of N,N-diisopropylethylamine to a flask. Stir and react at 20 °C for 10 h under a nitrogen atmosphere. Add ethyl acetate, extract and wash with an aqueous sodium carbonate solution. Dry the ethyl acetate organic layer with anhydrous magnesium sulfate, filter, and then heat and evaporate the filtrate, and cool and crystallize to obtain 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 the flask, stir and react at 30 °C for 3 h, extract and wash with aqueous sodium carbonate solution, dry the ethyl acetate organic layer with anhydrous magnesium sulfate, filter, and then rotary evaporate the filtrate. Add the product to an ethanol aqueous solution, heat and evaporate, and cool to crystallize to obtain diaminol-arginine.

[0027] (3) Add 180 mL of ethanol, 52 mmol of diaminol-arginine, and 50 mmol of glutaraldehyde to the flask equipped with a condenser reflux tube, stir and react at 55 °C for 8 h. Add water and dropwise add a hydrochloric acid solution with a mass fraction of 10%, adjust the pH to 6, heat and evaporate, cool to crystallize, wash with ethanol after filtration, and dry to obtain the 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, melt-blend and extrude in a twin-screw extruder. The temperatures of the first to fifth zones are 180 °C, 200 °C, 235 °C, 245 °C, and 240 °C, the screw speed is 150 r / min, and pelletize to obtain the high-strength antibacterial polypropylene composite material.

[0029] Comparative Example 1

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

[0031] Comparative Example 2

[0032] (1) Mix 9 kg of polypropylene, 1 kg of nylon 6, 50 g of arginine antibacterial agent, and 60 g of antioxidant 168, melt-blend and extrude in a twin-screw extruder. The temperatures of the first to fifth zones are 180 °C, 200 °C, 235 °C, 245 °C, and 240 °C, the screw speed is 150 r / min, and pelletize to obtain the 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, melt-blend and extrude in a twin-screw extruder. The temperatures of the first to fifth zones are 180 °C, 200 °C, 235 °C, 245 °C, and 240 °C, the screw speed is 150 r / min, and pelletize to obtain the 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 the first to fifth zones are 180 °C, 200 °C, 235 °C, 245 °C, and 240 °C, the screw speed is 150 r / min, and pelletize 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 condenser reflux tube, stir and react at 55 °C for 8 h, rotary evaporate to remove ethanol, wash with petroleum ether, and dry to obtain a 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 them in a twin-screw extruder. The temperatures of the first to fifth zones are 180 °C, 200 °C, 235 °C, 245 °C, and 240 °C, the screw speed is 150 r / min, and pelletize 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. Under a nitrogen atmosphere, stir and react at 30 °C for 7 h, add ethyl acetate, extract and wash with an aqueous sodium carbonate solution, dry the ethyl acetate organic layer with anhydrous magnesium sulfate, filter, and then heat and evaporate the filtrate, cool and crystallize to obtain a BOC precursor.

[0042] (2) Add 800 mL of an ethyl acetate solution of 4 mol / L HCl and 40 g of the BOC precursor to a flask, stir and react at 20 °C for 5 h, extract and wash with an aqueous sodium carbonate solution, dry the ethyl acetate organic layer with anhydrous magnesium sulfate, filter, and then rotary evaporate the filtrate. Add the product to an ethanol-water solution, heat and 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 condenser reflux tube, stir and react at 65 °C for 5 h, add water and dropwise add a 15% hydrochloric acid solution by mass to adjust the pH to 6, heat and evaporate, cool and crystallize, filter, wash with ethanol, and dry to obtain an 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 the first to fifth zones are 180 °C, 200 °C, 235 °C, 245 °C, and 240 °C, the screw speed is 200 r / min, and pelletize to obtain a high-strength antibacterial polypropylene composite material.

[0045] Example 3

[0046] (1) Add 200 mL of ethanol, 53 mmol of diaminol-arginine (prepared in Example 1), and 50 mmol of glutaraldehyde to a flask equipped with a condensing reflux tube, stir and react at 65 °C for 6 h, add water and dropwise add a 15% hydrochloric acid solution by mass fraction to adjust the pH to 5, heat and evaporate, cool and crystallize, wash with ethanol after filtration, and dry to obtain an 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 the first to fifth zones are 180 °C, 200 °C, 235 °C, 245 °C, and 240 °C, the screw speed is 100 r / min, and pelletize to obtain a high-strength antibacterial polypropylene composite material.

[0048] Inject the polypropylene composite material through an injection molding machine. The temperatures of the first to third zones are 215 °C, 240 °C, and 240 °C, and the pressure is 60 MPa to make a specimen. Test the tensile strength according to the standard of GB / T 1040.1-2018. Test the impact strength according to the standard of GB / T 1843-2008.

[0049] Table 1 Mechanical Property Tests of Polypropylene Composite Materials

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

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

[0053] In Comparative Example 5, Schiff base polymerization reaction was carried out using 1,6 - hexanediamine and glutaraldehyde, and the resulting polymer did not contain amide bonds, having poor compatibility with nylon 6 and having a certain impact on the mechanical properties of the composite material, resulting in the tensile strength and impact strength being lower than those in Example 1.

[0054] The antibacterial properties of the composite material were tested according to the standard of QB / T 2591 - 2003, using the composite material of Comparative Example 1 as the blank control sample. Antibacterial rate = (B - C) / B×100%. B is the average number of recovered bacteria of the blank control sample, cfu / sheet. C is the average number of recovered bacteria of the antibacterial plastic sample, cfu / sheet.

[0055]

[0056] After testing, arginine antibacterial agent was added to the composite materials of Examples 1 - 3. Its molecular side chain contained a large number of guanidine antibacterial groups. At the same time, the arginine antibacterial agent was a macromolecular polymer with good heat resistance. During the high - temperature melt blending and extrusion process, the antibacterial agent was not easily thermally decomposed. And maleic anhydride grafted polypropylene compatibilizer was added, enabling the arginine antibacterial agent to be evenly dispersed in the composite material matrix, thus effectively killing Staphylococcus aureus and Escherichia coli, making the composite material have strong antibacterial properties.

[0057] In Comparative Example 2, maleic anhydride grafted polypropylene compatibilizer was not added, and the compatibility between the arginine antibacterial agent and polypropylene was poor, with poor dispersibility in the composite material matrix, resulting in the antibacterial properties of the composite material being lower than those in Example 1.

[0058] In Comparative Example 3, arginine antibacterial agent was not added, and the antibacterial properties of the composite material were very poor.

[0059] In Comparative Example 4, the added L - arginine was a small - molecule compound with poor heat resistance and was easily thermally decomposed during the high - temperature melt blending and extrusion process, resulting in the antibacterial rate of the composite material being significantly lower than that in Example 1.

[0060] The Schiff base polymer of Comparative Example 5 does not contain a guanidine-based antibacterial group, and the antibacterial performance of the composite material is very poor.

[0061] The above are only the preferred specific embodiments of the present invention; however, the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution of the present invention and its improved concept, making equivalent substitutions or changes, should be covered by the protection scope of the present invention.

Claims

1. A high-strength antibacterial polypropylene composite material, characterized in that, 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 0.3-0.6 parts by weight of antioxidant; The preparation method of the arginine antibacterial agent is as follows: add ethanol, diaminoarginine with a molar ratio of (1.02-1.06):1, and glutaraldehyde into a flask equipped with a condensing reflux tube, stir to react, add water and dropwise add hydrochloric acid solution, heat and evaporate, cool and crystallize, wash with ethanol after filtration, and dry to obtain the arginine antibacterial agent; The structural formula of the diaminoarginine is 2. The high-strength antibacterial polypropylene composite material according to claim 1, wherein, The antioxidant is 1010 or antioxidant 168.

3. The high-strength antibacterial polypropylene composite material according to claim 1, wherein The temperature of the reaction is 55-65 °C, and the reaction time is 5-8 h.

4. The high-strength antibacterial polypropylene composite material according to claim 1, wherein The pH of the reaction solution is adjusted to 5-6 by dropwise adding hydrochloric acid solution.

5. The high-strength antibacterial polypropylene composite material according to claim 1, characterized in that The preparation method of the diaminoarginine is as follows: (1) Add N,N-dimethylformamide, BOC-L-arginine, ethylenediamine, O-benzotriazol-1-yl-N,N,N',N'-tetramethyluronium hexafluorophosphate, 1-hydroxybenzotriazole, and N,N-diisopropylethylamine into a flask, stir and react at 20-30 °C for 7-10 h in a nitrogen atmosphere, extract and purify by recrystallization to obtain the BOC precursor; (2) Add an ethyl acetate solution of HCl and the BOC precursor into a flask, stir and react at 20-30 °C for 3-5 h, extract and purify by recrystallization to obtain diaminoarginine.

6. The high-strength antibacterial polypropylene composite material according to claim 1, characterized in that, The molar ratio of BOC-L-arginine, ethylenediamine, O-benzotriazol-1-yl-N,N,N',N'-tetramethyluronium 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 1, wherein The concentration of the ethyl acetate solution of HCl in (2) is 4-5 mol / L.

8. A method for preparing a high-strength antibacterial polypropylene composite material according to any one of claims 1-7, characterized in that, The preparation method is as follows: mix polypropylene, nylon 6, maleic anhydride grafted polypropylene, arginine antibacterial agent, and antioxidant, and melt-blend and extrude in a twin-screw extruder, and pelletize to obtain a high-strength antibacterial polypropylene composite material.

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

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